Listing of Recent AOML Publications

**2010

Abdelzaher, A.M., M.E. Wright, C. Ortega, H.M. Solo-Gabriele, G. Miller, S. Elmir, X. Newman, P. Shih, J.A. Bonilla, T.D. Bonilla, C.J. Palmer, T. Scott, J. Lukasik, V.J. Harwood, S. McQuaig, C. Sinigalliano, M. Gidley, L.R.W. Plano, X. Zhu, J.D. Wang, and L.E. Fleming. Presence of pathogens and indicator microbes at a non-point source subtropical recreational marine beach. Applied and Environmental Microbiology, 76(3):724-732 (2010).

Swimming in ocean water, including ocean water at beaches not impacted by known point sources of pollution, is an increasing health concern. This study was an initial evaluation of the presence of indicator microbes and pathogens and the association among the indicator microbes, pathogens, and environmental conditions at a subtropical, recreational marine beach in south Florida impacted by non-point sources of pollution. Twelve water and eight sand samples were collected during four sampling events at high or low tide under elevated or reduced solar insolation conditions. The analyses performed included analyses of fecal indicator bacteria (FIB) (fecal coliforms, Escherichia coli, enterococci, and Clostridium perfringens), human-associated microbial source tracking (MST) markers (human polyomaviruses [HPyVs] and Enterococcus faecium esp gene), and pathogens (Vibrio vulnificus, Staphylococcus aureus, enterovirus, norovirus, hepatitis A virus, Cryptosporidium spp., and Giardia spp.). The enterococcus concentrations in water and sand determined by quantitative PCR were greater than the concentrations determined by membrane filtration measurement. The FIB concentrations in water were below the recreational water quality standards for three of the four sampling events, when pathogens and MST markers were also generally undetectable. The FIB levels exceeded regulatory guidelines during one event, and this was accompanied by detection of HPyVs and pathogens, including detection of the autochthonous bacterium V. vulnificus in sand and water, detection of the allochthonous protozoans Giardia spp. in water, and detection of Cryptosporidium spp. in sand samples. The elevated microbial levels were detected at high tide and under low-solar-insolation conditions. Additional sampling should be conducted to further explore the relationships between tidal and solar insolation conditions and between indicator microbes and pathogens in s ubtropical recreational marine waters impacted by non-point source pollution.

Aberson, S.D. Ten years of hurricane synoptic surveillance (1997-2006). Monthly Weather Review, 138(5):1536-1549 (2010).

Aberson, S.D., J. Cione, C.-C. Wu, M.M. Bell, J. Halverson, C. Fogarty, and M. Weissmann. Aircraft observations of tropical cyclones. In Global Perspectives on Tropical Cyclones: From Science to Mitigation, J.C.L. Chan and J.D. Kepert (ed.). World Scientific Publishing Company, 2nd edition, 227-240 (2010).

Nine different types of aircraft are currently in use to observe tropical cyclones and their environments for operations and research. The following is a description of those aircraft, their instrumentation, and the field programs with which they have been involved.

Aksoy, A., D.C. Dowell, and C. Snyder. A multicase comparative assessment of the ensemble Kalman filter for assimilation of radar observations, Part II: Short-range ensemble forecasts. Monthly Weather Review, 138(4):1273-1292 (2010).

The quality of convective-scale ensemble forecasts, initialized from analysis ensembles obtained through the assimilation of radar observations using an ensemble Kalman filter (EnKF), is investigated for cases whose behaviors span supercellular, linear, and multicellular organization. This work is the companion to Part I, which focused on the quality of analyses during the 60-min analysis period. Here, the focus is on 30-min ensemble forecasts initialized at the end of that period. As in Part I, the Weather Research and Forecasting (WRF) model is employed as a simplified cloud model at 2-km horizontal grid spacing. Various observation-space and state-space verification metrics, computed both for ensemble means and individual ensemble members, are employed to assess the quality of ensemble forecasts comparatively across cases. While the cases exhibit noticeable differences in predictability, the forecast skill in each case, as measured by various metrics, decays on a time scale of tens of minutes. The ensemble spread also increases rapidly but significant outlier members or clustering among members are not encountered. Forecast quality is seen to be influenced to varying degrees by the respective initial soundings. While radar data assimilation is able to partially mitigate some of the negative effects in some situations, the supercell case, in particular, remains difficult to predict even after 60 min of data assimilation.

Ali, M.M., G.J. Goni, and V. Jayaraman. Satellite-derived oceanic heat content improves cyclone predictions. Eos, Transactions, American Geophysical Union, 91(43):396 (doi:10.1029/2010EO430009) (2010).

No abstract.

Amornthammarong, N., P.B. Ortner, and J.-Z. Zhang. A simple, effective mixing chamber used in conjunction with a syringe pump for flow analysis. Talanta, 81(4-5), 1472-1476 (2010).

A simple, effective mixing chamber used in conjunction with a syringe pump for flow analysis is described and evaluated. A mixing chamber was constructed using a conventional 5 mL pipette tip and its performance compared with a widely used mixing coil. The results demonstrate that the mixing coil does not rapidly and completely mix solutions. Utilizing a configuration that reversed solution positions in the chamber with each mixing cycle, the proposed mixing chamber achieved complete mixing in a significantly shorter time than the mixing coil. The influence of injected sample volume on absorbance signals was evaluated by calculating an S_1/2 value for the system. As tested with a minimal rinse, the system has no discernable carryover. Testing this new approach in our previously described silicate measurement system resulted in a more than twofold improvement in sensitivity.

Aoyoma, M., et al., and J.-Z. Zhang. 2008 inter-laboratory comparison study of a reference material for nutrients in seawater. Meteorological Research Institute, Technical Report No 60, Tsukuba, Japan, 134 pp. (2010).

Autoclaved natural seawater collected in the North Pacific Ocean was used as a reference material for nutrients in seawater (RMNS) during an inter-laboratory comparison (I/C) study conducted in 2008. This study was a follow-up to previous studies conducted in 2003 and 2006. A set of six samples was distributed to each of 58 laboratories in 15 countries around the globe, and results were returned by 54 of those laboratories (15 countries). The homogeneities of samples used in the 2008 I/C study, based on analyses for three determinants, were improved compared to those of samples used in the 2003 and 2006 I/C studies. Results of these I/C studies indicate that most of the participating laboratories have an analytical technique for nutrients that is sufficient to provide data of high comparability. The differences between reported concentrations from the same laboratories in the 2006 and 2008 I/C studies for the same batch of RMNS indicate that most of the laboratories have been maintaining internal comparability for two years. Thus, with the current high level of performance in the participating laboratories, the use of a common reference material and the adaptation of an internationally accepted nutrient scale system would increase comparability among laboratories worldwide, and the use of a certified reference material would establish traceability. In the 2008 I/C study we observed a problem of non-linearity of the instruments of the participating laboratories similar to that observed among the laboratories in the 2006 I/C study. This problem of non-linearity should be investigated and discussed to improve comparability for the full range of nutrient concentrations. For silicate comparability in particular, we see relatively larger consensus standard deviations than those for nitrate and phosphate.

Arndt, D.S., M.O. Baringer, M. R. Johnson (editors). State of the Climate in 2009. Bulletin of the American Meteorological Society, 91(6):S1-S224 (2010).

This 20th annual State of the Climate report highlights the climate conditions that characterized 2009, including notable extreme events. In total, 37 Essential Climate Variables are reported to more completely characterize the State of the Climate in 2009.

Atlas, R. Application of remotely sensed wind measurements to ocean surface wind analyses. Proceedings, 2010 International Geoscience and Remote Sensing Symposium (IGARSS), Honolulu, HI, July 25-30, 2010. Institute of Electrical and Electronic Engineers, 3 pp. (2010).

The assimilation and validation of cross-calibrated, multi-satellite ocean surface wind data is described. The principal data set covers the global ocean for the twenty-two year period from 1987 through 2009 with six-hour and 25-km resolution. This data set is produced by combining all ocean surface wind speed observations from SSM/I, AMSR-E, and TMI, and all ocean surface wind vector observations from QuikSCAT and SeaWinds. An enhanced variational analysis method (VAM) performs quality control and combines these data with available ship and buoy data and ECMWF analyses. The VAM analyses fit the data used very closely and contain small-scale structures not present in operational analyses. Comparisons with withheld observations are also shown to be very good. These data should be extremely useful to atmospheric and oceanic research, and to air-sea interaction studies.

Atlas, R. Impact of satellite surface-wind data on weather prediction. SPIE News, doi:10.1117/2.1201007.003120, 2 pp. (2010).

Microwave remote sensing of ocean-surface winds from space enables improved quantification of their impact on weather analyses and forecasts.

Atlas, R. Review of observing system simulation experiments to evaluate the potential impact of lidar winds on weather prediction. Proceedings, 2010 International Geoscience and Remote Sensing Symposium (IGARSS), Honolulu, HI, July 25-30, 2010. Institute of Electrical and Electronic Engineers, 4 pp. (2010).

Observing System Simulation Experiments (OSSEs) are an important tool for evaluating the potential impact of proposed new observing systems, as well as for evaluating trade-offs in observing system design, and in developing and assessing improved methodology for assimilating new observations. Extensive OSSEs have been conducted at NASA/GSFC and NOAA/AOML in collaboration with Simpson Weather Associates and operational data assimilation centers over the last 25 years. These OSSEs determined correctly the quantitative potential for several proposed satellite observing systems to improve weather prediction prior to their launch, and evaluated trade-offs in orbits, coverage, and accuracy for space-based wind lidars. In this paper, we summarize OSSE methodology and present results from OSSEs to assess the potential impact of lidar winds.

Atlas, R., R.N. Hoffman, S.M. Leidner, and J. Ardizzone. Impact of satellite surface wind observations on ocean surface wind analyses and numerical weather prediction. Proceedings, SPIE Optical Engineering and Applications Conference, August 1-5, 2010, San Diego, CA. International Society of Optical Engineering, 8 pp. (2010).

Since the 1970s, an extensive series of data impact studies has been performed to evaluate and enhance the impact of satellite surface wind data on ocean surface wind analyses and fluxes, atmospheric and oceanic modeling, and weather prediction. These studies led to the first beneficial impacts of scatterometer winds on numerical weather prediction (NWP), the development of the methodology to assimilate surface wind speeds derived from passive microwave radiometry, and the operational use of satellite surface winds by marine forecasters and NWP models. In recent years, the impact of these data on NWP has decreased as more competing data have become available; however, the results of our recent experiments still show a very significant impact of satellite surface winds on ocean surface wind analyses and on the prediction of selected storms over the oceans.

Baringer, M.O., T.O. Kanzow, C.S. Meinen, S.A. Cunningham, D. Rayner, W.E. Johns, H.L. Bryden, J. J.-M. Hirschi, L.M. Beal, and J. Marotzke. The meridional overturning circulation. In State of the Climate in 2009, D.S. Arndt, M.O. Baringer, and M.R. Johnson (eds.). Bulletin of the American Meteorological Society, 91(6):66-69 (2010).

No abstract.

Bell, G.D., E.S. Blake, T.B. Kimberlain, C.W. Landsea, R.J. Pasch, J. Schemm, and S.B. Goldenberg. Atlantic basin. In State of the Climate in 2009, D.S. Arndt, M.O. Baringer, and M.R. Johnson (eds.). Bulletin of the American Meteorological Society, 91(6):84-88 (2010).

No abstract.

Bell, M.M., and M.T. Montgomery. Sheared deep vortical convection in pre-depression Hagupit during TCS08. Geophysical Research Letters, 37(6):L06802, doi:10.1029/2009GL042313 (2010).

Airborne Doppler radar observations from the recent Tropical Cyclone Structure 2008 (TCS08) field campaign in the western North Pacific reveal the presence of deep, buoyant and vortical convective features within a vertically-sheared, westward-moving pre-depression disturbance that later developed into Typhoon Hagupit. On two consecutive days, the observations document tilted, vertically coherent precipitation, vorticity, and updraft structures in response to the complex shearing flows impinging on and occurring within the disturbance near 18 north latitude. The observations and analyses herein suggest that the low-level circulation of the pre-depression disturbance was enhanced by the coupling of the low-level vorticity and convergence in these deep convective structures on the meso-gamma scale, consistent with recent idealized studies using cloud-representing numerical weather prediction models. Further examination of these new observations is needed to quantify the relative role of these vortical convection features in the tropical cyclone spin up process.

Beron-Vera, F.J., M.J. Olascoaga, and G.J. Goni. Surface ocean mixing inferred from different multisatellite altimetry measurements. Journal of Physical Oceanography, 40(11):2466-2480 (doi:10.1175/2010JPO4458.1) (2010).

Two sea surface height (SSH) anomaly fields distributed by Archiving, Validation, and Interpretation of Satellite Oceanographic (AVISO) altimetry are evaluated in terms of the effects that they produce on mixing. One SSH anomaly field, tagged REF, is constructed using measurements made by two satellite altimeters; the other SSH anomaly field, tagged UPD, is constructed using measurements made by up to four satellite altimeters. Advection is supplied by surface geostrophic currents derived from the total SSH fields resulting from the addition of these SSH anomaly fields to a mean SSH field. Emphasis is placed on the extraction from the currents of Lagrangian coherent structures (LCSs), which, acting as skeletons for patterns formed by passively advected tracers, entirely control mixing. The diagnostic tool employed to detect LCSs is provided by the computation of finite-time Lyapunov exponents. It is found that currents inferred using UPD SSH anomalies support mixing with characteristics similar to those of mixing produced by currents inferred using REF SSH anomalies. This result mainly follows from the fact that, being more easily characterized as chaotic than turbulent, mixing as sustained by currents derived using UPD SSH anomalies is quite insensitive to spatiotemporal truncations of the advection field.

Borges, A.V., S.R. Alin, F.P. Chavez, P. Vlahos, K.S. Johnson, J.T. Holt, W.M. Balch, N. Bates, R. Brainard, W.-J. Cai, C.T.A. Chen, K. Currie, M. Dai, M. DeGrandpre, B. Delille, A. Dickson, W. Evans, R.A. Feely, G.E. Friederich, G.-C. Gong, B. Hales, N. Hardman-Mountford, J. Hendee, J.M. Hernandez-Ayon, M. Hood, E. Huertas, D. Hydes, D. Ianson, E. Krasakopoulou, E. Litt, A. Luchetta, J. Mathis, W.R. McGillis, A. Murata, J. Newton, J. Olafsson, A. Omar, F.F. Perez, C. Sabine, J.E. Salisbury, R. Salm, V.V.S.S. Sarma, B. Schneider, M. Sigler, H. Thomas, D. Turk, D. Vandemark, R. Wanninkhof, and B. Ward. A global sea surface carbon observing system: Inorganic and organic carbon dynamics in coastal oceans. In OceanObs09: Sustained Ocean Observations and Information for Society (Volume 2), J. Hall, D.E. Harrison, and D. Stammer (eds.). European Space Agency Publication, WPP-306, 20 pp. (2010).

Coastal environments are an important component of the global carbon cycle, and probably more vulnerable than the open ocean to anthropogenic forcings. Due to strong spatial heterogeneity and temporal variability, carbon flows in coastal environments are poorly constrained. Hence, an integrated, international, and interdisciplinary program of ship-based hydrography, Voluntary Observing Ship (VOS) lines, time-series moorings, floats, gliders, and autonomous surface vessels with sensors for pCO₂ and ancillary variables are recommended to better understand present day carbon cycle dynamics, quantify air-sea CO₂ fluxes, and determine future long-term trends of CO₂ in response to global change forcings (changes in river inputs, in the hydrological cycle, in circulation, sea-ice retreat, expanding oxygen minimum zones, ocean acidification, ) in the coastal oceans. Integration at the international level is also required for data archiving, management, and synthesis that will require multi-scale approaches including the development of biogeochemical models and use of remotely sensed parameters. The total cost of these observational efforts is estimated at about 50 million U.S. dollars per year.

Bourassa, M.A., A. Stoffelen, H. Bonekamp, P. Chang, D.B. Chelton, J. Courtney, R. Edson, J. Figa, Y. He, H. Hersbach, K. Hilburn, Z. Jelenak, K.A. Kelly, R. Knabb, T. Lee, E.J. Lindstrom, W.T. Liu, D.G. Long, W. Perrie, M. Portabella, M.D. Powell, E. Rodriguez, D.K. Smith, V. Swail, and F.J. Wentz. Remotely sensed winds and wind stresses for marine forecasting and ocean modeling. In OceanObs09: Sustained Ocean Observations and Information for Society (Volume 2), J. Hall, D.E. Harrison, and D. Stammer (eds.). European Space Agency Publication, WPP-306, 17 pp. (2010).

No abstract.

Brainard, R.E., D. Butterfield, M. Eakin, R.A. Feely, D.K. Gledhill, E. Kehn, K. Shamberger, A.J. Sutton, O. Vetter, and C. Young. Pacific Islands region ocean acidification research implementation plan, pp. 59-76. In NOAA Ocean and Great Lakes Acidification Research and Implementation Plan, A.J. Sutton (ed.). NOAA Special Report, 143 pp. (2010).

No abstract.

Brainard, R.E., S. Bainbridge, R. Brinkman, C.M. Eakin, M. Field, J.-P. Gattuso, D. Gledhill, L. Gramer, A. Green, J. Hendee, R.K. Hoeke, S.J. Holbrook, O. Hoegh-Guldberg, M. Lammers, D. Manzello, M. McManus, R. Moffitt, M. Monaco, J.A. Morgan, D. Obura, S. Planes, R.J. Schmitt, C. Steinberg, H. Sweatman, O.J. Vetter, C. Wilkinson, and K.B. Wong. An international network of coral reef ecosystem observing systems (I-CREOS). In OceanObs09: Sustained Ocean Observations and Information for Society (Volume 2), J. Hall, D.E. Harrison, and D. Stammer (eds.). European Space Agency Publication, WPP-306, 15 pp. (2010).

Coral reefs are complex, biologically diverse, and highly valued ecosystems that are declining worldwide due to climate change and ocean acidification, overfishing, land-based sources of pollution, and other anthropogenic threats. To assist policymakers and resource managers at international, national, and local levels in effectively implementing ecosystem approaches to sustainable management and conservation of coral reefs and their biodiversity, it is necessary to have timely, unbiased integrated ecosystem observations about the conditions of coral reefs and the complex physical and biogeochemical processes supporting them. To provide these interdisciplinary ecosystem observations, an International network of Coral Reef Ecosystem Observing Systems (I-CREOS) is proposed that will organize and build upon existing coral reef observation systems being developed around the globe. This paper uses examples of some developing observation systems to demonstrate some of the approaches and technologies available for acquiring biological, physical, and geochemical observations using combinations of visual surveys, moored instrument arrays, spatial-hydrographic and water quality surveys, satellite remote sensing, and hydrodynamic and ecosystem modeling. This fledgling, and hopefully expanding, network of observing systems represents the early stages of an integrated ecosystem observing system for coral reefs capable of providing policymakers, resource managers, researchers, and other stakeholders with essential information products needed to assess various responses of coral reef ecosystems to natural variability and anthropogenic perturbations. While significant challenges and gaps in the I-CREOS network remain, it demonstrably fulfills the requirements of an operational, integrated, interdisciplinary, coastal component of GOOS. Continued support, further development, and open expansion of this emerging network are encouraged and needed to ensure the continually increasing value of the networks observational and predictive capacity. With common goals to maximize versatility, accessibility, and robustness, the existing infrastructure and capacity provide a foundation by which increased global cooperation and coordination could naturally lead to a globally comprehensive I-CREOS.

Brandt, P., V. Hormann, A. Kortzinger, M. Visbeck, G. Krahmann, L. Stramma, R. Lumpkin, and C. Schmid. Changes in the ventilation of the oxygen minimum zone of the tropical North Atlantic. Journal of Physical Oceanography, 40(8):1784-1801 (2010).

Changes in the ventilation of the oxygen minimum zone (OMZ) of the tropical North Atlantic are studied using oceanographic data from 18 research cruises carried out between 28.5° and 23°W during 1999-2008 as well as historical data referring to the period 1972-85. In the core of the OMZ at about 400-m depth, a highly significant oxygen decrease of about 15 µmol kg^-1 is found between the two periods. During the same time interval, the salinity at the oxygen minimum increased by about 0.1. Above the core of the OMZ, within the central water layer, oxygen decreased too, but salinity changed only slightly or even decreased. The scatter in the local oxygen-salinity relations decreased from the earlier to the later period, suggesting a reduced filamentation due to mesoscale eddies and/or zonal jets acting on the background gradients. Here it is suggested that latitudinally alternating zonal jets with observed amplitudes of a few centimeters per second in the depth range of the OMZ contribute to the ventilation of the OMZ. A conceptual model of the ventilation of the OMZ is used to corroborate the hypothesis that changes in the strength of zonal jets affect mean oxygen levels in the OMZ. According to the model, a weakening of zonal jets, which is in general agreement with observed hydrographic evidences, is associated with a reduction of the mean oxygen levels that could significantly contribute to the observed deoxygenation of the North Atlantic OMZ.

Braun, S.A., M.T. Montgomery, K.J. Mallen, and P.D. Reasor. Simulation and interpretation of the genesis of Tropical Storm Gert (2005) as part of the NASA Tropical Cloud Systems and Processes Experiment. Journal of the Atmospheric Sciences, 67(4):999-1025 (2010).

Several hypotheses have been put forward for the mechanisms of generation of surface circulation associated with tropical cyclones. This paper examines high-resolution simulations of Tropical Storm Gert (2005), which formed in the Gulf of Mexico during NASAs Tropical Cloud Systems and Processes Experiment, to investigate the development of low-level circulation and its relationship to the precipitation evolution. Two simulations are examined: one that better matches available observations but underpredicts the storms minimum sea level pressure and a second one that somewhat overintensifies the storm but provides a set of simulations that encapsulates the overall genesis and development characteristics of the observed storm. The roles of convective and stratiform precipitation processes within the mesoscale precipitation systems that formed Gert are discussed. During 21-25 July, two episodes of convective system development occurred. In each, precipitation system evolution was characterized by intense and deep convective upward motions followed by increasing stratiform-type vertical motions (upper-level ascent, low-level descent). Potential vorticity (PV) in convective regions was strongest at low levels while stratiform-region PV was strongest at midlevels, suggesting that convective processes acted to spin up lower levels prior to the spinup of middle levels by stratiform processes. Intense vortical hot towers (VHTs) were prominent features of the low-level cyclonic vorticity field. The most prominent PV anomalies persisted more than 6 h and were often associated with localized minima in the sea level pressure field. A gradual aggregation of the cyclonic PV occurred as existing VHTs near the center continually merged with new VHTs, gradually increasing the mean vorticity near the center. Nearly concurrently with this VHT-induced development, stratiform precipitation processes strongly enhanced the mean inflow and convergence at middle levels, rapidly increasing the midlevel vorticity. However, the stratiform vertical motion profile is such that while it increases midlevel vorticity, it decreases vorticity near the surface as a result of low-level divergence. Consequently, the results suggest that while stratiform precipitation regions may significantly increase cyclonic circulation at midlevels, convective vortex enhancement at low to mid levels is likely necessary for genesis.

Bunya, S., J.C. Dietrich, J.J. Westerink, B.A. Ebersole, J.M. Smith, J.H. Atkinson, R. Jensen, D.T. Resio, R.A. Luettich, C. Dawson, V.J. Cardone, A.T. Cox, M.D. Powell, H.J. Westerink, and H.J. Roberts. A high-resolution coupled riverine flow, tide, wind, wind wave, and storm surge model for southern Louisiana and Mississippi, Part I: Model development and validation. Monthly Weather Review, 138(2):345-377 (2010).

A coupled system of wind, wind wave, and coastal circulation models has been implemented for southern Louisiana and Mississippi to simulate riverine flows, tides, wind waves, and hurricane storm surge in the region. The system combines the NOAA Hurricane Research Division Wind Analysis System (H*WIND) and the Interactive Objective Kinematic Analysis (IOKA) kinematic wind analyses, the Wave Model (WAM) offshore and Steady-State Irregular Wave (STWAVE) nearshore wind wave models, and the Advanced Circulation (ADCIRC) basin to channel-scale unstructured grid circulation model. The system emphasizes a high-resolution (down to 50 m) representation of the geometry, bathymetry, and topography; nonlinear coupling of all processes including wind wave radiation stress-induced set up; and objective specification of frictional parameters based on land-cover databases and commonly used parameters. Riverine flows and tides are validated for no storm conditions, while winds, wind waves, hydrographs, and high water marks are validated for Hurricanes Katrina and Rita.

Cai, W.-J., X. Hu, W.-J. Huang, L.-Q. Jiang, Y. Wang, T.-H. Peng, and X. Zhang. Alkalinity distribution in the western North Atlantic Ocean margins. Journal of Geophysical Research, 115:C08014, doi:10.1029/2009JC005482, 15 pp. (2010).

Total alkalinity (TA) distribution and its relationship with salinity (S) along the western North Atlantic Ocean (wNAO) margins from the Labrador Sea to tropical areas are examined in this study. Based on the observed TA-S patterns, the mixing processes that control alkalinity distribution in these areas can be categorized into a spectrum of patterns that are bracketed by two extreme mixing types, i.e., alongshore current-dominated and river-dominated. Alongshore current-dominated mixing processes exhibit a segmented mixing line with a shared mid-salinity end-member. In such cases (i.e., Labrador Sea, Gulf of Maine, etc.), the y-intercept of the high salinity segment of the mixing line is generally higher than the local river alkalinity values, and it reflects the mixing history of the alongshore current. In contrast, in river-dominated mixing (Amazon River, Caribbean Sea, etc.), good linear relationships between alkalinity and salinity are generally observed, and the zero salinity intercepts of the TA-S regressions roughly match those of the regional river alkalinity values. TA-S mixing lines can be complicated by rapid changes in the river end-member value and by another river nearby with a different TA value (e.g., Mississippi-Atchafalaya/Gulf of Mexico). In the wNAO margins, regression intercepts and river end-members have a clear latitudinal distribution pattern, increasing from a low of ~300 µmol kg^-1 in the Amazon River plume to a high value between ~500-1100 µmol kg^-1 in the middle and high latitude margins. The highest value of ~2400 µmol kg is observed in the Mississippi River influenced areas. In addition to mixing control, biological processes such as calcification and benthic alkalinity production may also affect ocean margin alkalinity distribution. Therefore, deriving inorganic carbon system information in coastal oceans using alkalinity-salinity relationships, in particular, those of generic nature, may lead to significant errors.

Cai, W.-J., L. Chen, B. Chen, Z. Gao, S.-H. Lee, J. Chen, D. Pierrot, K. Sullivan, Y. Wang, X. Hu, W.-J. Huang, Y. Zhang, S. Xu, A. Murata, J.M. Grebmeier, E.P. Jones, and H. Zhang. Decrease in the CO₂ uptake capacity in an ice-free Arctic Ocean basin. Science, 329(5991):556-559 (2010).

It has been predicted that the Arctic Ocean will sequester much greater amounts of carbon dioxide (CO₂) from the atmosphere as a result of sea ice melt and increasing primary productivity. However, this prediction was made on the basis of observations from either highly productive ocean margins or ice-covered basins before the recent major ice retreat. We report here a high-resolution survey of sea-surface CO₂ concentration across the Canada Basin, showing a great increase relative to earlier observations. Rapid CO₂ invasion from the atmosphere and low biological CO₂ drawdown are the main causes for the higher CO₂, which also acts as a barrier to further CO₂ invasion. Contrary to the current view, we predict that the Arctic Ocean basin will not become a large atmospheric CO₂ sink under ice-free conditions.

Carsey, T.P., H. Casanova, C. Drayer, C. Featherstone, C. Fischer, K. Goodwin, J. Proni, A. Saied, C. Sinigalliano, J. Stamates, P. Swart, and J.-Z. Zhang. FACE outfalls survey cruise: October 6-19, 2006. NOAA Technical Report, OAR AOML-38, 130 pp. (CD-ROM) (2010).

In October 2006, a cruise of the Florida Area Coastal Environment (FACE) program was conducted aboard the NOAA RV Nancy Foster. The cruise visited coastal sites in the vicinity of six treated wastewater boils in south Florida. The outfalls included in this study were those for the South Central, Boca Raton, Broward, Hollywood, Miami-Dade North, and Miami-Dade Central wastewater treatment plants. The boils and associated down-current plumes were studied to produce a data set of ocean currents, ocean chemistry, and microbiology. Seawater was analyzed for nitrate + nitrite, nitrite, ammonia, orthophosphate, and silicate. Samples down-current of each boil were collected by a conductivity-temperature-depth (CTD) rosette at three depths--near-surface, mid-depth, and near-bottom--and from three transects--inshore of the boil, approximately in line with the boil, and further offshore of the boil. Overall, surface samples showed the highest nutrient concentrations versus samples taken at other depths; surface samples taken nearest the boil showed the highest nutrient concentrations in comparison to other samples collected in the vicinity of the outfall. The only exception was Si, which had a maximum observed concentration at an inlet sampling site. The outfall plume was found to be dynamic, irregular, and mainly in the upper 10 m of the water column. Samples were analyzed for a variety of microbes; the detection frequency was higher for the southern boils compared to the northern boils. The CTD data indicated a tendency toward better defined and deeper thermoclines at the 20-30 m depth in the deeper (more offshore) casts; the thermocline showed a tendency to shoal at 10-20 m and become less well defined in more inshore casts.

Coddington, O.M., P. Pilewskie, J. Redemann, S. Platnick, P.B. Russell, K.S. Schmidt, W.J. Gore, J. Livingston, G. Wind, and T. Vukicevic. Examining the impact of overlying aerosols on the retrieval of cloud optical properties from passive remote sensing. Journal of Geophysical Research, 115:D10211, doi:10.1029/2009JD012829 (2010).

Haywood et al. (2004) showed that an aerosol layer above a cloud can cause a bias in the retrieved cloud optical thickness and effective radius. Monitoring for this potential bias is difficult because space-based passive remote sensing cannot unambiguously detect or characterize aerosol above cloud. We show that cloud retrievals from aircraft measurements above cloud and below an overlying aerosol layer are a means to test this bias. The data were collected during the Intercontinental Chemical Transport Experiment (INTEX-A) study based out of Portsmouth, New Hampshire, United States, above extensive, marine stratus cloud banks affected by industrial outflow. Solar Spectral Flux Radiometer (SSFR) irradiance measurements taken along a lower level flight leg above cloud and below aerosol were unaffected by the overlying aerosol. Along upper level flight legs, the irradiance reflected from cloud top was transmitted through an aerosol layer. We compare SSFR cloud retrievals from below-aerosol legs to satellite retrievals from the Moderate Resolution Imaging Spectroradiometer (MODIS) in order to detect an aerosol-induced bias. In regions of small variation in cloud properties, we find that SSFR and MODIS-retrieved cloud optical thickness compares within the uncertainty range for each instrument while SSFR effective radius tend to be smaller than MODIS values (by 1-2 �µ) and at the low end of MODIS uncertainty estimates. In regions of large variation in cloud properties, differences in SSFR and MODIS-retrieved cloud optical thickness and effective radius can reach values of 10 and 10 µm, respectively. We include aerosols in forward modeling to test the sensitivity of SSFR cloud retrievals to overlying aerosol layers. We find an overlying absorbing aerosol layer biases SSFR cloud retrievals to smaller effective radii and optical thickness while nonabsorbing aerosols had no impact.

Conzemius, R.J., and M.T. Montgomery. Mesoscale convective vortices in multiscale, idealized simulations: Dependence on background state, interdependency with moist baroclinic cyclones, and comparison with BAMEX observations. Monthly Weather Review, 138(4):1119-1139 (2010).

A set of multiscale, nested, idealized numerical simulations of mesoscale convective systems (MCSs) and mesoscale convective vortices (MCVs) was conducted. The purpose of these simulations was to investigate the dependence of MCV development and evolution on background conditions and to explore the relationship between MCVs and larger, moist baroclinic cyclones. In all experiments, no mesoscale convective system (MCS) developed until a larger-scale, moist baroclinic system with surface pressure amplitude of at least 2 hPa was present. The convective system then enhanced the development of the moist baroclinic system by its diabatic production of eddy available potential energy (APE), which led to the enhanced baroclinic conversion of basic-state APE to eddy APE. The most rapid potential vorticity (PV) development occurred in and just behind the leading convective line. The entire system grew upscale with time as the newly created PV rotated cyclonically around a common center as the leading convective line continued to expand outward. Ten hours after the initiation of deep moist convection, the simulated MCV radii, heights of maximum winds, tangential velocity, and shear corresponded reasonably well to their counterparts in BAMEX. The increasing strength of the simulated MCVs with respect to larger values of background CAPE and shear supports the hypothesis that as long as convection is present, CAPE and shear both add to the strength of the MCV.

Cunningham, S., M. Baringer, W. Johns, J. Toole, S. Osterhus, J. Fischer, A. Piola, E. McDonagh, S. Lozier, U. Send, T. Kanzow, J. Marotzke, M. Rhein, S. Garzoli, S. Rintoul, B. Sloyan, S. Speich, L. Talley, J. Baehr, C. Meinen, A.-M. Treguier, and P. Lherminier. The present and future system for measuring the Atlantic Meridionnal Overturning circulation and heat transport. In OceanObs09: Sustained Ocean Observations and Information for Society (Volume 2), J. Hall, D.E. Harrison, and D. Stammer (eds.). European Space Agency Publication, WPP-306, 16 pp. (2010).

The Atlantic Ocean circulation redistributes up to 25% of the global combined atmosphere-ocean heat flux and so is important for the mean climate of the Atlantic sector of the Northern Hemisphere. This meridional heat flux is accomplished by both the Atlantic Meridional Overturning Circulation (AMOC) and by basin-wide horizontal gyre circulations. In the North Atlantic subtropical latitudes the AMOC dominates the meridional heat flux, while in subpolar latitudes and in the subtropical South Atlantic the gyre circulations are also important. Climate models suggest the AMOC will slow over the coming decades as the earth warms, causing widespread cooling in the Northern hemisphere and additional sea-level rise. Monitoring systems for selected components of the AMOC have been in place in some areas for decades, nevertheless the present observational network provides only a partial view of the AMOC, and does not unambiguously resolve the full variability of the circulation. Additional observations, building on existing measurements, are required to more completely quantify the Atlantic meridional heat transport. A basin-wide monitoring array along 26.5°N has been continuously measuring the strength and vertical structure of the AMOC and meridional heat transport since March 31, 2004. The array has demonstrated its ability to observe the AMOC variability at that latitude and also a variety of surprising variability that will require substantially longer time series to understand fully. Here we propose monitoring the Atlantic meridional heat transport throughout the Atlantic at selected critical latitudes that have already been identified as regions of interest for the study of deep water formation and the strength of the subpolar gyre, transport variability of the Deep Western Boundary Current (DWBC) as well as the upper limb of the AMOC, and inter-ocean and intrabasin exchanges with the ultimate goal of determining regional and global controls for the AMOC in the North and South Atlantic Oceans. These new arrays will continuously measure the full depth, basin-wide or choke-point circulation and heat transport at a number of latitudes, to establish the dynamics and variability at each latitude and then their meridional connectivity. Modeling studies indicate that adaptations of the 26.5°N type of array may provide successful AMOC monitoring at other latitudes. However, further analysis and the development of new technologies will be needed to optimize cost effective systems for providing long term monitoring and data recovery at climate time scales. These arrays will provide benchmark observations of the AMOC that are fundamental for assimilation, initialization, and the verification of coupled hindcast/forecast climate models.

Diaz, M.R., J.W. Jacobson, K.D. Goodwin, S.A. Dunbar, and J.W. Fell. Molecular detection of harmful algal blooms (HABs) using locked nucleic acids and bead array technology. Limnology and Oceanography: Methods, 8:269-284 (2010).

Harmful algal blooms (HABs) are a serious public health risk in coastal waters. As the intensity and frequency of HABs continue to rise, new methods of detection are needed for reliable identification. Herein, we developed a high-throughput, multiplex, bead array technique for the detection of the dinoflagellates Karenia brevis and Karenia mikimotoi. The method combined the Luminex detection system with two novel technologies: locked nucleic acidmodified oligonucleotides (LNA) and Mirus Label IT nucleic acid technology. To study the feasibility of the method, we evaluated the performance of modified and unmodified LNA probes with amplicon targets that were biotin labeled with two different strategies: direct chemical labeling (Mirus Label IT) versus enzymatic end-labeling (single biotinylated primer). The results illustrated that LNA probes hybridized to complementary single-stranded DNA with better affinity and displayed higher fluorescence intensities than unmodified oligonucleotide DNA probes. The latter effect was more pronounced when the assay was carried out at temperatures above 53°C degree. As opposed to the enzymatic 5' terminal labeling technique, the chemical labeling method enhanced the level of fluorescence by as much as ~83%. The detection limits of the assay, which were established with LNA probes and the Mirus Label IT system, ranged from 0.05 to 46 copies of rRNA. This high-throughput method, which represents the first molecular detection strategy to integrate Luminex technology with LNA probes and Mirus Label IT, can be adapted for the detection of other HABs and is well suited for the monitoring of red tides at pre-blooming and blooming conditions.

Dietrich, J.C., S. Bunya, J.J. Westerink, B.A. Ebersole, J.M. Smith, J.H. Atkinson, R. Jensen, D.T. Resio, R.A. Luettich, C. Dawson, V.J. Cardone, A.T. Cox, M.D. Powell, H.J. Westerink, and H.J. Roberts. A high-resolution coupled riverine flow, tide, wind, wind wave, and storm surge model for southern Louisiana and Mississippi, Part II: Synoptic description and analysis of Hurricanes Katrina and Rita. Monthly Weather Review, 138(2):378-404 (2010).

Hurricanes Katrina and Rita were powerful storms that impacted southern Louisiana and Mississippi during the 2005 hurricane season. In Part I, the authors describe and validate a high-resolution coupled riverine flow, tide, wind, wave, and storm surge model for this region. Herein, the model is used to examine the evolution of these hurricanes in more detail. Synoptic histories show how storm tracks, winds, and waves interacted with the topography, the protruding Mississippi River delta, eastwest shorelines, manmade structures, and low-lying marshes to develop and propagate storm surge. Perturbations of the model, in which the waves are not included, show the proportional importance of the wave radiation stress gradient induced setup.

Di Nezio, P.N., and G.J. Goni. Identifying and estimating biases between XBT and Argo observations using satellite altimetry. Journal of Atmospheric and Oceanic Technology, 27(1):226-240 (2010).

A methodology is developed to identify and estimate systematic biases between expendable bathythermograph (XBT) and Argo observations using satellite altimetry. Pseudoclimatological fields of isotherm depth are computed by least squares adjustment of in situ XBT and Argo data to altimetry-derived sea height anomaly (SHA) data. In regions where the correlations between isotherm depth and SHA are high, this method reduces sampling biases in the in situ observations by taking advantage of the high temporal and spatial resolution of satellite observations. Temperature profiles from deep XBTs corrected for a bias identified and adopted during the 1990s are considered in this study. The analysis shows that the pseudoclimatological isotherm depths derived from these corrected XBTs are predominantly deeper than the Argo-derived estimates during the 2000-2007 period. The XBT-minus-Argo differences increase with depth consistent with hypothesized problems in the XBT fall-rate equation. The depth-dependent XBT-minus-Argo differences suggest a global positive bias of 3% of the XBT depths. The fact that this 3% error is robust among the different ocean basins provides evidence for changes in the instrumentation, such as changes in the terminal velocity of the XBTs. The value of this error is about the inverse of the correction to the XBT fall-rate equation (FRE) implemented in 1995, suggesting that this correction, while adequate during the 1990s, is no longer appropriate and could be the source of the 3% error. This result suggests that for 2000-2007, the XBT dataset can be brought to consistency with Argo by using the original FRE coefficients without the 1995 correction.

Di Nezio, P.N., A.C. Clement, and G.A. Vecchi. Reconciling differing views of tropical Pacific climate change. Eos, Transactions, American Geophysical Union, 91(16):141-142 (2010).

No abstract.

Dohan, K., F. Bonjean, L. Centurioni, M. Cronin, G. Lagerloef, D.-K. Lee, R. Lumpkin, N.A. Maximenko, P.P. Niiler, and H. Uchida. Measuring the global ocean surface circulation with satellite and in situ observations. In OceanObs09: Sustained Ocean Observations and Information for Society (Volume 2), J. Hall, D.E. Harrison, and D. Stammer (eds.). European Space Agency Publication, WPP-306, 14 pp. (2010).

In the past two decades, the Global Drifter Program (GDP), satellite altimeter missions, precise gravity models and radiometer and scatterometer winds, have provided a detailed resolution of the global sea surface velocity (SSV) and its variability. Out of these has emerged a detailed, unprecedented, description of the surface circulation (calibrated to 15 m depth), including formerly unknown zonal features and an updated global mean dynamic topography. Using the GDP, along with long time series current meter moorings and numerous ship acoustic Doppler current profiler (ADCP) sections for calibration and validation, we can now resolve the spatial and temporal variability of the global surface currents from satellite sea surface topography and vector wind measurements. This record extends from 1993 to present and provides key dynamical insights into the tropical dynamics of ENSO and extra-tropical variations on intra-seasonal to decadal time scales. Beyond the basic oceanographic and climate research applications, the data are useful to marine applications (shipping, fishing, ocean yachting, search and rescue, pollution monitoring, etc.) This paper describes the state of the observing system, data quality and principal scientific insights during the last decade. The synergy of the satellite and in situ components of this observing system has been essential for resolving the circulation on a global synoptic basis. The future observing system requires at a minimum the continuation of these key components. The OceanObs99 GDP requirements (one measurement per month per 5 x 5 degrees) are reviewed for adequacy to define the mean circulation, seasonal to inter-annual variability, calibrate satellite SSV, resolve eddy kinetic energy, coastal processes, and deploying ancillary sensors for surface salinity and PCO₂.

Dong, S., S.T. Gille, J. Sprintall, and E.J. Fetzer. Assessing the potential of the Atmospheric Infrared Sounder (AIRS) surface temperature and specific humidity in turbulent heat flux estimates in the Southern Ocean. Journal of Geophysical Research, 115(C5):C05013, doi:10.1029/2009JC005542 (2010).

Surface air temperature (T_A), sea surface temperature (T_O), and surface specific humidity (q_a) satellite retrievals from the Atmospheric Infrared Sounder (AIRS) are compared with shipboard measurements across Drake Passage for the period from September 2002 to June 2007. The objective is to evaluate whether AIRS retrievals, in conjunction with microwave sea surface temperatures from the Advanced Microwave Scanning Radiometer (AMSRE), can provide sufficiently accurate parameters to estimate sensible and latent heat fluxes in the data-limited Southern Ocean. The collocated data show that both AIRS T_A and T_O are colder than those from shipboard measurements, with a time mean bias of -2.03°C for T_A and -0.22°C for T_O. Results show that air-sea temperature difference (T_A - T_O), q_a, and relative humidity (RH) are the major factors contributing to the differences between satellite and shipboard temperature measurements. Differences in AIRS and shipboard T_A (DELTA T_A) decrease with increasing T_A - T_O, and DELTA T_A increases with increasing RH, whereas differences in AIRS and shipboard T_O (DELTA T_O) increase with both increasing T_A - T_O and increasing q_a. The time mean q_a from AIRS is lower than the shipboard q_a by 0.69 g/kg. Statistical analyses suggest that T_A - T_O, cloud, and q_a are the major contributors to the q_a difference (DELTA q_a). DELTA q_a becomes more negative with increasing T_A - T_O and increasing cloud fraction. DELTA q_a also becomes more negative as q_a increases. Compared with T_A, T_O, and T_A - T_O, from the National Centers for Environmental Prediction/National Center for Atmospheric Research Reanalysis (NCEP), AIRS-derived and AMSRE-derived variables show more small-scale spatial structure, as is also typical of the ship observations. Although AIRS q_a gives a better representation of the full range of values of shipboard q_a, its deviation from shipboard q_a is relatively large compared to NCEP q_a. Compared with several existing gridded flux products, turbulent fluxes estimated from AIRS and AMSRE data using bulk algorithms are better able to represent the full range of flux values estimated from shipboard parameters.

Eakin, C.M., C.J. Nim, R.E. Brainard, C. Aubrecht, C. Elvidge, D.K. Gledhill, F. Muller-Karger, P.J. Mumby,W.J. Skirving, A.E. Strong, M. Wang, S. Weeks, F. Wentz, and D. Ziskin. Monitoring coral reefs from space. Oceanography, 23(4):118-133 (2010).

Coral reefs are one of the world's most biologically diverse and productive ecosystems. However, these valuable resources are highly threatened by human activities. Satellite remotely-sensed observations enhance our understanding of coral reefs and some of the threats facing them by providing global spatial and time-series data on reef habitats and the environmental conditions influencing them in near-real time. This review highlights many of the ways in which satellites are currently used to monitor coral reefs and their threats, and provides a look toward future needs and capabilities.

Eakin, C.M., J.A. Morgan, S.F. Heron, T.B. Smith, G. Liu, L. Alvarez-Filip, B. Baca, E. Bartels, C. Bastidas, C. Bouchon, M. Brandt, A.W. Bruckner, L. Bunkley-Williams, A. Cameron, B.D. Causey, M. Chiappone, T.R.L. Christensen, M.J.C. Crabbe, O. Day, E. de la Guardia, G. Diaz-Pulido, D. DiResta, D.L. Gil-Agudelo, D.S. Gilliam, R.N. Ginsburg, S. Gore, H.M. Guzman, J.C. Hendee, et al. Caribbean corals in crisis: Record thermal stress, bleaching, and mortality in 2005. PloS ONE, 5(11):e13969 (doi:10.1371/journal.pone.0013969) (2010).

The rising temperature of the worlds oceans has become a major threat to coral reefs globally as the severity and frequency of mass coral bleaching and mortality events increase. In 2005, high ocean temperatures in the tropical Atlantic and Caribbean resulted in the most severe bleaching event ever recorded in the basin. Satellite-based tools provided warnings for coral reef managers and scientists, guiding both the timing and location of researchers' field observations as anomalously warm conditions developed and spread across the greater Caribbean region from June to October 2005. Field surveys of bleaching and mortality exceeded prior efforts in detail and extent, and provided a new standard for documenting the effects of bleaching and for testing nowcast and forecast products. Collaborators from 22 countries undertook the most comprehensive documentation of basin-scale bleaching to date and found that over 80% of corals bleached and over 40% died at many sites. The most severe bleaching coincided with waters nearest a western Atlantic warm pool that was centered off the northern end of the Lesser Antilles. Thermal stress during the 2005 event exceeded any observed from the Caribbean in the prior 20 years, and regionally-averaged temperatures were the warmest in over 150 years. Comparison of satellite data against field surveys demonstrated a significant predictive relationship between accumulated heat stress (measured using NOAA Coral Reef Watchs Degree Heating Weeks) and bleaching intensity. This severe, widespread bleaching and mortality will undoubtedly have long-term consequences for reef ecosystems and suggests a troubled future for tropical marine ecosystems under a warming climate.

Elipot, S., R. Lumpkin, and G. Prieto. Modifications of inertial oscillations by the mesoscale eddy field. Journal of Geophysical Research, 115:C09010, doi:10.1029/2009JC05679, 20 pp. (2010).

The modification of near-surface near-inertial oscillations (NIOs) by the geostrophic vorticity is studied globally from an observational standpoint. Surface drifter are used to estimate NIO characteristics. Despite its spatial resolution limits, altimetry is used to estimate the geostrophic vorticity. Three characteristics of NIOs are considered: the relative frequency shift with respect to the local inertial frequency; the near-inertial variance; and the inverse excess bandwidth, which is interpreted as a decay time scale. The geostrophic mesoscale flow shifts the frequency of NIOs by approximately half its vorticity. Equatorward of 30°N and S, this effect is added to a global pattern of blue shift of NIOs. While the global pattern of near-inertial variance is interpretable in terms of wind forcing, it is also observed that the geostrophic vorticity organizes the near-inertial variance; it is maximum for near zero values of the Laplacian of the vorticity and decreases for nonzero values, albeit not as much for positive as for negative values. Because the Laplacian of vorticity and vorticity are anticorrelated in the altimeter data set, overall, more near-inertial variance is found in anticyclonic vorticity regions than in cyclonic regions. While this is compatible with anticyclones trapping NIOs, the organization of near-inertial variance by the Laplacian of vorticity is also in very good agreement with previous theoretical and numerical predictions. The inverse bandwidth is a decreasing function of the gradient of vorticity, which acts like the gradient of planetary vorticity to increase the decay of NIOs from the ocean surface. Because the altimetry data set captures the largest vorticity gradients in energetic mesoscale regions, it is also observed that NIOs decay faster in large geostrophic eddy kinetic energy regions.

Enfield, D.B., and L. Cid-Serrano. Secular and multidecadal warmings in the North Atlantic and their relationships with major hurricane activity. International Journal of Climatology, 30(2):174-184 (2010).

Analysis of recent literature finds weaknesses in arguments to the effect that the Atlantic multidecadal oscillation (AMO)--roughly 50-90 year fluctuations in North Atlantic sea surface temperatures--is externally forced by anthropogenic aerosols and greenhouse gases rather than an internal climate mode, plus indications from other sources that the contrary may be true. We are led to the conclusion that the AMO is probably comprised of both natural and anthropogenic forcing in ways that preclude a physically based separation of the two, using the limited historical data sets. A straightforward quadratic fitting of trend to temperature data accounts for some of the 20th century nonlinearity in secular warming and separates the secular and multidecadal components of variability without inherent assumptions about the nature of the multidecadal fluctuations. Doing this shows that the 20th century secular ocean warming in the North Atlantic is about equal to the peak-to-peak amplitude of the multidecadal fluctuations. However, over the last quarter-century (1975-2000) the most recent multidecadal warming has been almost three times the secular sea surface temperature (SST) increase over the main development region (MDR) for major Atlantic hurricanes. In the last quarter-century the multidecadal increase in late summer Atlantic warm pool (AWP) size (area of SSTs in excess of 28°C) has been 36%, and the secular increase, 14%. Projections to the year 2025 show that the cumulative change in summer warm pool size since 1975 will depend critically on whether a subsequent cooling in the multidecadal cycle occurs, comparable to the warming between 1975 and 2000 AD. This places a high premium on understanding to what extent the AMO is a man-made or a natural phenomenon.

Feely, R.A., R. Wanninkhof, J. Stein, M.F. Sigler, E. Jewett, F. Arzayus, and D.K. Gledhill (NOAA Ocean Acidification Steering Committee). NOAA Ocean and Great Lakes Acidification Research and Implementation Plan, A.J. Sutton (ed.). NOAA Special Report, 143 pp. (2010).

No abstract.

Feely, R.A., C.L. Sabine, R. Wanninkhof, S.R. Alin, E. Jewett, D.K. Gledhill, J. Dunne, P. McElhany, A.J. Sutton, D.S. Busch, F. Arzayus, B. Sunda, J. Geubtner, J. Hare, O. Vetter, and S. Hankin. Rationale and strategy for a national ocean acidification program, pp. 3-29. In NOAA Ocean and Great Lakes Acidification Research and Implementation Plan, A.J. Sutton (ed.). NOAA Special Report, 143 pp. (2010).

No abstract.

Fleisher, J.M., L.E. Fleming, H.M. Solo-Gabriele, J.K. Kish, C.D. Sinigalliano, L.W. Plano, S.M. Elmir, J.D. Wang, K.F. Withum, T. Shibata, M.L. Gidley, A. Abdelzaher, G. He, C. Ortega, X. Zhu, M.D. Wright, J.A. Hollenbeck, and L.C. Backer. The BEACHES Study: Health effects and exposures from nonpoint source microbial contaminants in subtropical recreational marine waters. International Journal of Epidemiology, 39(5):1291-1298 (2010).

Microbial water quality indicators, found in high concentrations in sewage, are used to determine whether water is safe for recreational purposes. Recently, concerns have been raised about the appropriate use of indicators to regulate recreational water bodies, particularly non-point source sub/tropical recreational marine waters. A group of 1303 adult regular bathers were randomly assigned to bather and non-bather groups, with subsequent follow-up for reported illness, in conjunction with an ongoing extensive environmental sampling of indicator organisms (enterococcus) and pathogens. After controlling for non-water related risk factors/possible confounders, bathers were 1.75 times (95% confidence interval = 0.94-3.26; p = 0.078) more likely to report gastrointestinal illness relative to non bathers; bathers were 4.46 times (0.99-20.97; p = 0.051) more likely to report acute febrile respiratory illness; and bathers were 5.51 times (2.68-11.36; p = 0.<0.0001) more likely to report skin illness relative to non-bathers after seven days of follow up from beach exposure. There was an apparent dose-response relationship between bather exposure to increasing levels of enterococcus and risks of reported skin and gastrointestinal illness, and some evidence of increased risk of respiratory illness among bathers relative to nonbathers. There was a possible threshold effect for gastrointestinal illness at approximately 40 CFU/100 mL of enterococcus; however, no threshold effect was observed for skin illness. Human exposures to and health risks from microbial pollution may occur even in a non-point source recreational marine environment.

Forteza, E. Analysis of governance in Coiba National Park in Panama. M.S. thesis. University of Miami, Rosenstiel School of Marine and Atmospheric Science, 61 pp. (2010).

This internship is part of a continued effort to contribute to the analysis, discussion and accomplishment of the Management Plan of Coiba National Park, which is located off the Pacific coast of Panama and was declared a UNESCO World Heritage Site in 2005. The National Assembly of Panama adopted legislation, known as Law No. 44, which established Coiba National Park and an adjacent Special Zone of Marine Protection. The Law also established a Governing Council and other working committees. This analysis of governance was based on the revision of legal documents, interviews with members of committees and a review of minutes from meetings of different committees. The analysis covered aspects of relevance as the decision-making process, the interaction between all interested institutions, the participation of the general public and the economic consequences from the establishment of the park for the region. This study revealed that the Governing Council has consolidated his position as the maximum authority in Coiba National Park and was capable of elaborating and approving a renewed Management Plan that will guide conservation goals during the next five years. The analysis also showed that the Governing Council still has many important problems to solve, such as the removal of cattle from Coiba Island, the approval of a Management Plan for the Special Zone of Marine Protection, and the elaboration of a Five-Year Scientific Plan.

Freeland, H.J., D. Roemmich, S.L. Garzoli, P.-Y. Le Traon, M. Ravichandran, S. Riser, V. Thierry, S. Wijffels, M. Belbeoch, J. Gould, F. Grant, M. Ignazewski, B. King, B. Klein, K.A. Mork, B. Owens, S. Pouliquen, A. Sterl, T. Suga, M.-S. Suk, P. Sutton, A. Troisi, P.J. Velez-Belchi, and J. Xi. ARGO: A decade of progress. In OceanObs09: Sustained Ocean Observations and Information for Society (Volume 2), J. Hall, D.E. Harrison, and D. Stammer (eds.). European Space Agency Publication, WPP-306, 13 pp. (2010).

No abstract.

Garzoli, S.L., S. Speich, A. Piola, and E. Campos. South Atlantic Meridional Overturning Circulation (SAMOC)Third workshop. CLIVAR Exchanges, 54(4):28-29 (2010).

No abstract.

Garzoli, S.L., O. Boebel, H. Bryden, R.A. Fine, M. Fukasawa, S. Gladyshev, G. Johnson, M. Johnson, A. MacDonald, C.S. Meinen, H. Mercier, A. Orsi, A. Piola, S. Rintoul, S. Speich, M. Visbeck, and R. Wanninkhof. Progressing towards global sustained deep ocean observations. In OceanObs09: Sustained Ocean Observations and Information for Society (Volume 2), J. Hall, D.E. Harrison, and D. Stammer (eds.). European Space Agency Publication, WPP-306,12 pp. (2010).

No abstract.

Gledhill, D.K., T. Goedeke, K. Helmle, J. Hendee, A. Hilting, E. Jewett, B. Keller, D. Manzello, M. Miller, E. Rule, B. Sunda, and R. Wanninkhof. Southeast Atlantic and Gulf of Mexico region ocean acidification research implementation plan, pp. 77-91. In NOAA Ocean and Great Lakes Acidification Research Implementation Plan, A.J. Sutton (ed.). NOAA Special Report, 143 pp. (2010).

No abstract.

Goni, G.J., J.A. Knaff, and I.-I. Lin. TC heat potential. In State of the Climate in 2009, D.S. Arndt, M.O. Baringer, and M.R. Johnson (eds.). Bulletin of the American Meteorological Society, 91(6):99-100 (2010).

No abstract.

Goni, G., M. DeMaria, J. Knaff, C. Sampson, J. Price, A. Mehra, I. Ginis, I.-I. Lin, P. Sandery, S. Ramos-Buarque, M.M. Ali, F. Bringas, S. Aberson, R. Lumpkin, G. Halliwell, C. Lauer, E. Chassignet, A. Mavume, and K. Kang. The ocean observing system for tropical cyclone intensification forecasts and studies. In OceanObs09: Sustained Ocean Observations and Information for Society (Volume 2), J. Hall, D.E. Harrison, and D. Stammer (eds.). European Space Agency Publication, WPP-306, 13 pp. (2010).

No abstract.

Goni, G., D. Roemmich. R. Molinari, G. Meyers, C. Sun, T. Boyer, M. Baringer, V. Gouretski, P. DI NEZIO, F. Reseghetti, G. Vissa, S. Swart, R. Keeley, S. Garzoli, T. Rossby, C. Maes, and G. Reverdin. The Ship of Opportunity Program. In OceanObs09: Sustained Ocean Observations and Information for Society (Volume 2), J. Hall, D.E. Harrison, and D. Stammer (eds.). European Space Agency Publication, WPP-306, 19 pp. (2010).

The Ship of Opportunity Program (SOOP) is an international World Meteorological Organization (WMO)-Intergovernmental Oceanographic Commission (IOC) program that addresses both scientific and operational goals to contribute to building a sustained ocean observing system. The SOOP main mission is the collection of upper ocean temperature profiles using eXpendable BathyThermographs (XBTs), mostly from volunteer vessels. The XBT deployments are designated by their spatial and temporal sampling goals or modes of deployment (Low Density, Frequently Repeated, and High Density) and sample along well-observed transects, on either large or small spatial scales, or at special locations such as boundary currents and chokepoints, all of which are complementary to the Argo global broad scale array. A multi-national review of the global upper ocean thermal networks carried out in 1999 [1] and presented at the OceanObs99 conference recommended evolving from broad-scale XBT sampling to increased spatial and temporal transect-based sampling anticipating the implementation of the Argo float network and continued satellite altimetry observations. The objective of the present manuscript is to review the present status of networks against the objectives set during OceanObs99, to present key scientific contributions of XBT observations, and to offer new perspectives for the future of the XBT network. The commercial shipping industry has changed in the past decade, toward fewer routes and more frequent changes of ships and routing impacting the temporal continuity of some XBT transects. In spite of these changes, many routes now have, in addition to XBT sampling, measurements from ThermoSalinoGraphs (TSGs), eXpendable Conductivity Temperature and Depth (XCTD), partial pressure of CO₂, Acoustic Doppler Current Profiler (ADCP), Continuous Plankton Recorders (CPR), marine meteorology, fluorescence, and radiometer sensors. In addition, recent studies of the XBT fall rate are being evaluated with the goal of optimizing the XBT historical record for climate research applications. The ongoing value of the Ship Of Opportunity networks is viewed through their extended time series and their integrative relationships with other elements of the ocean observing system including, for example, profiling floats, satellite altimetry, and air-sea flux measurements. Improved capabilities in ocean data assimilation modeling and expansion to support large scale multidisciplinary research will further enhance value in the future.

Gruskin, Z. Structure and evolution of a possible U.S. landfalling tropical cyclone in 2006. Monthly Weather Review, 138(1):265-278 (2010).

A tropical disturbance made landfall near Morehead City, North Carolina, on 27 June 2006. Surface observations, Air Force reconnaissance, and Doppler velocity data suggest that the disturbance had a closed surface circulation at landfall, with maximum 1-min surface winds >18 m s^-1, the threshold of tropical storm strength. A cyclostrophic wind calculation using Doppler velocity data and surface observations indicates that the circulation of the disturbance likely caused the tropical storm force winds observed, rather than an environmental pressure gradient or short-lived convective process. Doppler velocity cross sections of the disturbance further suggest that the disturbance was warm core, and an analysis of the disturbances environment reveals that latent heat of condensation was likely a large source of energy for the disturbance, though there was some baroclinic forcing. These observations and analyses make a compelling case for the upgrade of the disturbance to a tropical storm in the best-track database.

Hamid, S., B.M. Golam Kibria, S. Gulati, M. Powell, B. Annane, S. Cocke, J.-P. Pinelli, K. Gurley, and S.-C. Chen. Predicting losses of residential structures in the state of Florida by the public hurricane loss evaluation model. Statistical Methodology, 7(5):552-573 (2010).

As an environmental phenomenon, hurricanes cause significant property damage and loss of life in coastal areas almost every year. Although a number of commercial loss projection models have been developed to predict the property losses, only a handful of studies are available in the public domain to predict damage for hurricane prone areas. The state of Florida has developed an open, public model for the purpose of probabilistic assessment of risk to insured residential property associated with wind damage from hurricanes. The model comprises three components; viz. the atmospheric science component, the engineering component and the actuarial science component. The atmospheric component includes modeling the track and intensity life cycle of each simulated hurricane within the Florida threat area. Based on historical hurricane statistics, thousands of storms are simulated allowing determination of the wind risk for all residential zip code locations in Florida. The wind risk information is then provided to the engineering and actuarial components to model damage and average annual loss, respectively. The actuarial team finds the county-wise loss and the total loss for the entire state of Florida. The computer team then compiles all information from atmospheric science, engineering and actuarial components, processes all hurricane related data and completes the project. The model was submitted to the Florida Commission on Hurricane Loss Projection Methodology for approval and went through a rigorous review and was revised as per the suggestions of the commission. The final model was approved for use by the insurance companies in Florida by the commission. At every stage of the process, statistical procedures were used to model various parameters and validate the model. This paper presents a brief summary of the main components of the model (meteorology, vulnerability and actuarial) and then focuses on the statistical validation of the same.

Haus, B.K., D. Jeong, M.A. Donelan, J.A. Zhang, and I. Savelyev. Relative rates of sea-air heat transfer and frictional drag in very high winds. Geophysical Research Letters, 37(7):L07802, doi:10.1029/2009GL042206 (2010).

Hurricanes are fueled by evaporation and convection from the ocean and they lose energy through the frictional drag of the atmosphere on the ocean surface. The relative rates of these processes have been thought to provide a limit on the maximum potential hurricane intensity. Here we report laboratory observations of these transfers for scaled winds equivalent to a strong Category 1 hurricane (38 ms^-1). We show that the transfer coefficient ratio holds closely to a level of ~0.5 even in the highest observed winds, where previous studies have suggested there is a distinct regime change at the air-sea interface. This value is well below the expected threshold value for intense hurricanes of 0.75. Recent three-dimensional model studies also find that the coefficient ratio can be much lower than 0.75, which suggests that other factors such as eyewall and/or vortex dynamics are responsible for the formation of very strong hurricanes.

Huang, X.-L., and J.-Z. Zhang. Spatial variation in sediment-water exchange of phosphorus in Florida Bay: AMP as a model organic compound. Environmental Science and Technology, 44(20):7790-7795 (doi:10.1021/es100057r) (2010).

Dissolved organic phosphorus (DOP) has been recognized as dominant components in total dissolved phosphorus (TDP) pools in many coastal waters, and its exchange between sediment and water is an important process in biogeochemical cycle of phosphorus. Adenosine monophosphate (AMP) was employed as a model DOP compound to simulate phosphorus exchange across sediment-water interface in Florida Bay. The sorption data from 40 stations were fitted to a modified Freundlich equation and provided a detailed spatial distribution both of the sediments zero equilibrium phosphorus concentration (EPC_0-T) and of the distribution coefficient (K_d-T) with respect to TDP. The K_d-T was found to be a function of the index of phosphorus saturation (IPS), a molar ratio of the surface reactive phosphorus to the surface reactive iron oxide content in the sediment, across the entire bay. However, the EPC_0-T was found to correlate to the contents of phosphorus in the eastern bay only. Sediment in the western bay might act as a source of the phosphorus in the exchange process due to their high EPC_0-T and low K_d-T, whereas sediments in the eastern bay might act as a sink because of their low EPC_0-T and high K_d-T. These results strongly support the hypothesis that both phosphorus and iron species in calcareous marine sediments play a critical role in governing the sediment-water exchange of both phosphate and DOP in the coastal and estuarine ecosystems.

Hydes, D.J., M. Aoyama, a. Aminot, K. Bakker, S. Becker, S. Coverly, A. Daniel, A.G. Dickson, O. Grosso, R. Kerouel, J. van Ooijen, K. Sato, T. Tanhua, E.M.S. Woodward, and J.-Z. Zhang. Determination of dissolved nutrients (N, P, Si) in seawater with high precision and inter-comparability using gas-segmented continuous flow analyzers. The GO-SHIP Repeat Hydrography Manual: A Collection of Expert Reports and Guidelines, IOCCP Report No. 14, ICPO Publication Series No. 134, Version 1, 87 pp. (2010).

The Global Ocean Ship-based Hydrographic Investigations Program (GO-SHIP) brings together scientists with interests in physical oceanography, the carbon cycle, marine biogeochemistry and ecosystems, and other users and collectors of ocean interior data to develop a sustained global network of hydrographic sections as part of the Global Ocean Climate Observing System. A series of manuals and guidelines are being produced by GO-SHIP which update those developed by the World Ocean Circulation Experiment (WOCE) in the early 1990s. Analysis of the data collected in WOCE suggests that improvements are needed in the collection of nutrient data if they are to be used for determining change within the ocean interior. Production of this manual is timely as it coincides with the development of reference materials for nutrients in seawater (RMNS). These RMNS solutions will be produced in sufficient quantities and be of sufficient quality that they will provide a basis for improving the consistency of nutrient measurements both within and between cruises. This manual is a guide to suggested best practice in performing nutrient measurements at sea. It provides a detailed set of advice on laboratory practice for all the procedures surrounding the use of gas-segmented continuous flow analyzers (CFA) for the determination of dissolved nutrients (usually ammonium, nitrate, nitrite, phosphate and silicate) at sea. It does not proscribe the use of a particular instrument or related chemical method as these are well described in other publications. The manual provides a brief introduction to the CFA method, the collection and storage of samples, considerations in the preparation of reagents and the calibrations of the system. It discusses how RMNS solutions can be used to track the performance of a system during a cruise and between cruises. It provides a format for the meta-data that need to be reported alongside the sample data at the end of a cruise so that the quality of the reported data can be evaluated and set in context relative to other data sets. Most importantly the central manual is accompanied by a set of nutrient standard operating procedures (NSOPs) that provide detailed information on key procedures that are necessary if best quality data are to be achieved consistently. These cover sample collection and storage, an example NSOP for the use of a CFA system at sea, high precision preparation of calibration solutions, assessment of the true calibration blank, checking the linearity of a calibration and the use of internal and externally prepared reference solutions for controlling the precision of data during a cruise and between cruises. An example meta-data report and advice on the assembly of the quality control and statistical data that should form part of the meta-data report are also given.

Ismail, S., R.A. Ferrare, E.V. Browell, S.A. Kooi, J.P. Dunion, G. Heymsfield, A. Notari, C.F. Butler, S. Burton, M. Fenn, T.N. Krishnamurti, M.K. Biswas, G. Chen, and B. Anderson. LASE measurements of water vapor, aerosol, and cloud distributions in Saharan air layers and tropical disturbances. Journal of the Atmospheric Sciences, 67(4):1026-1047 (2010).

The Lidar Atmospheric Sensing Experiment (LASE) on board the NASA DC-8 measured high-resolution profiles of water vapor and aerosols, and cloud distributions in 14 flights over the eastern North Atlantic during the NASA African Monsoon Multidisciplinary Analyses (NAMMA) field experiment. These measurements were used to study African easterly waves (AEWs), tropical cyclones (TCs), and the Saharan air layer (SAL). These LASE measurements represent the first simultaneous water vapor and aerosol lidar measurements to study the SAL and its interactions with AEWs and TCs. Three case studies were selected for detailed analysis: (i) a stratified SAL, with fine structure and layering (unlike a well-mixed SAL), (ii) a SAL with high relative humidity (RH), and (iii) an AEW surrounded by SAL dry air intrusions. Profile measurements of aerosol scattering ratios, aerosol extinction coefficients, aerosol optical thickness, water vapor mixing ratios, RH, and temperature are presented to illustrate their characteristics in the SAL, convection, and clear air regions. LASE extinction-to-backscatter ratios for the dust layers varied from 35 ± 5 to 45 ± 5 sr, well within the range of values determined by other lidar systems. LASE aerosol extinction and water vapor profiles are validated by comparison with onboard in situ aerosol measurements and GPS dropsonde water vapor soundings, respectively. An analysis of LASE data suggests that the SAL suppresses low-altitude convection. Midlevel convection associated with the AEW and transport are likely responsible for high water vapor content observed in the southern regions of the SAL on 20 August 2008. This interaction is responsible for the transfer of about 7 x 10¹⁵ J (or 8 x 10³ J m^-2) latent heat energy within a day to the SAL. Initial modeling studies that used LASE water vapor profiles show sensitivity to and improvements in model forecasts of an AEW.

Jiang, L.-Q., W.-J. Cai, R.A. Feely, Y. Wang, X. Guo, D.K. Gledhill, X. Hu, F. Arzayus, F. Chen, J. Hartmann, and L. Zhang. Carbonate mineral saturation states along the U.S. east coast. Limnology and Oceanography, 55(6):2424-2432 (2010).

To assess the impact of ocean acidification on the carbonate chemistry of the shelf waters off the southeastern United States (South Atlantic Bight [SAB]), we measured carbonate mineral saturation states from January 2005 to May 2006. The findings reveal that aragonite (V_arag: 2.64.0) and calcite (V_cal: 4.16.0) saturation states were considerably higher than those recently reported along the West Coast of North America. Different water mass age between the Atlantic and Pacific Oceans during global ocean circulation is the primary reason for the higher carbonate mineral saturation states in the SAB than along the west coast. The contrasting water temperatures in the two coasts contribute to such differences. Both upwelling and freshwater discharge also play important roles in controlling saturation state. Carbonate mineral saturation in the surface water of the west coast is strongly controlled by the upwelling of high-salinity, low-temperature, low-oxygen, and low-pH deep water. In comparison, saturation states in the surface water of the SAB coast are rarely affected by upwelling. Instead, they are strongly influenced by the input of low-saturation-state water from rivers. Continued increases of atmospheric CO₂ under the Intergovernmental Panel on Climate Change B1 emission scenario will decrease the carbonate mineral saturation states by up to 40% by the end of this century, and aragonite will approach undersaturation near the coast.

Juranek, L.W., R.C. Hamme, J. Kaiser, R. Wanninkhof, and P.D. Quay. Evidence of O₂ consumption in underway seawater lines: Implications for air-sea O₂ and CO₂ fluxes. Geophysical Research Letters, 37:L01601, doi:10.1029/2009GL040423 (2010).

We observed O₂ deficits of 0.5 to 2.0% (1 to 4 µmol/kg) in the underway seawater lines of three different ships. Deficits in O₂/Ar and isotopic enrichments in dissolved O₂ observed in underway seawater lines indicate a respiratory removal process. A 1% respiratory bias in underway lines would lead to a 2.5-5 µatm (2.5-5 µbar) enhancement in surface water pCO₂. If an underway pCO₂ bias of this magnitude affected all measurements, the global oceanic carbon uptake based on pCO₂ climatologies would be 0.5-0.8 Pg/yr higher than the present estimate of 1.6 Pg/yr. Treatment of underway lines with bleach for several hours and thorough flushing appeared to minimize O₂ loss. Given the increasing interest in underway seawater measurements for the determination of surface CO₂ and O₂ fluxes, respiration in underway seawater lines must be identified and eliminated on all observing ships to ensure unbiased data.

Jury, M.R., and D.B. Enfield. Environmental patterns associated with active and inactive Caribbean hurricane seasons. Journal of Climate, 23(8):2146-2160 (2010).

This study of hurricanes passing through the Caribbean in the 1950-2005 period reveals that seasons with more intense hurricanes occur with the onset of Pacific La Niña events and when Atlantic SSTs west of Africa are above normal. Composites of NCEP reanalysis fields with regard to Caribbean hurricanes reveal development of an anomalous equatorial Atlantic zonal overturning circulation (upper easterly/lower westerly) that shifts toward the Caribbean coincident with a westward spread of the cold tongue in the east Pacific. Ocean-atmosphere coupling is promoted through interaction of the southern Hadley cell and the Atlantic ITCZ. A heat budget analysis suggests that evaporation governs SSTs in the major development region (MDR) and near Venezuela, but the signal is weak prior to May. Using the knowledge gained, statistical algorithms are developed to predict Caribbean hurricanes at seasonal lead times. These make use of equatorial Pacific SST, subtropical Atlantic SST, and the zonal Walker cell over the Atlantic.

Kanzow, T., S.A. Cunningham, W.E. Johns, J.J-M. Hirschi, J. Marotzke, M.O. Baringer, C.S. Meinen, M.P. Chidichimo, C. Atkinson, L.M. Beal, H.L. Bryden, and J. Collins. Seasonal variability of the Atlantic meridional overturning circulation at 26.5°N. Journal of Climate, 23(21):5678-5698 (doi:10.1175/2010JCL13389.1) (2010).

The Atlantic meridional overturning circulation (AMOC) makes the strongest oceanic contribution to the meridional redistribution of heat. Here, an observation-based, 48-month-long time series of the vertical structure and strength of the AMOC at 26.5°N is presented. From April 2004 to April 2008, the AMOC had a mean strength of 18.7 ± 2.1 Sv (1 Sv � 10⁶ m³ s^-1) with fluctuations of 4.8 Sv rms. The best guess of the peak-to-peak amplitude of the AMOC seasonal cycle is 6.7 Sv, with a maximum strength in autumn and a minimum in spring. While seasonality in the AMOC was commonly thought to be dominated by the northward Ekman transport, this study reveals that fluctuations of the geostrophic midocean and Gulf Stream transports of 2.2 and 1.7 Sv rms, respectively, are substantially larger than those of the Ekman component (1.2 Sv rms). A simple model based on linear dynamics suggests that the seasonal cycle is dominated by wind stress curl forcing at the eastern boundary of the Atlantic. Seasonal geostrophic AMOC anomalies might represent an important and previously underestimated component of meridional transport and storage of heat in the subtropical North Atlantic. There is evidence that the seasonal cycle observed here is representative of much longer intervals. Previously, hydrographic snapshot estimates between 1957 and 2004 had suggested a long-term decline of the AMOC by 8 Sv. This study suggests that aliasing of seasonal AMOC anomalies might have accounted for a large part of the inferred slowdown.

Kaplan, J., M. DeMaria, and J.A. Knaff. A revised tropical cyclone rapid intensification index for the Atlantic and eastern North Pacific basins. Weather and Forecasting, 25(1):220-241 (2010).

A revised rapid intensity index (RII) is developed for the Atlantic and eastern North Pacific basins. The RII uses large-scale predictors from the Statistical Hurricane Intensity Prediction Scheme (SHIPS) to estimate the probability of rapid intensification (RI) over the succeeding 24 h utilizing linear discriminant analysis. Separate versions of the RII are developed for the 25-, 30-, and 35-kt RI thresholds, which represent the 90th (88th), 94th (92nd), and 97th (94th) percentiles of 24-h over water intensity changes of tropical and subtropical cyclones in the Atlantic (eastern North Pacific) basins from 1989 to 2006, respectively. The revised RII became operational at the NHC prior to the 2008 hurricane season. The relative importance of the individual RI predictors is shown to differ between the two basins. Specifically, the previous 12-h intensity change, upper-level divergence, and vertical shear have the highest weights for the Atlantic basin, while the previous 12-h intensity change, symmetry of inner-core convection, and the difference in a systems current and maximum potential intensity are weighted highest in the eastern North Pacific basin. A verification of independent forecasts from the 2006 and 2007 hurricane seasons shows that the probabilistic RII forecasts are generally skillful in both basins when compared to climatology. Moreover, when employed in a deterministic manner, the RII forecasts were superior to all other available operational intensity guidance in terms of the probability of detection (POD) and false alarm ratio (FAR). Specifically, the POD for the RII ranged from 15% to 59% (53% to 73%) while the FAR ranged from 71% to 85% (53% to 79%) in the Atlantic (eastern North Pacific) basins, respectively, for the three RI thresholds studied. Nevertheless, the modest POD and relatively high FAR of the RII and other intensity guidance demonstrate the difficulty of predicting RI, particularly in the Atlantic basin.

Keeley, R., M. Pazos, and B. Bradshaw. Data management system for surface drifters. In OceanObs09: Sustained Ocean Observations and Information for Society (Volume 2), J. Hall, D.E. Harrison, and D. Stammer (eds.). European Space Agency Publication, WPP-306, 7 pp. (2010).

The large scale deployment of surface drifters has its origins in the FGGE programme in the late 1970s. Over the course of the next 25 years, surface drifters have become routinely used in all oceans so that now there are more than 1250 operating. The data management systems to handle the data returned from these platforms started with FGGE and have evolved. The main difference between the early years and now from a data system perspective is the volume and timeliness of reporting the data, though more variables are also being measured. Presently there are more than 1 million records reported in real-time and such high volumes are straining processing systems that were originally set up for fewer records and manual scrutiny of the data. The future system will need more sophisticated algorithms for automatic detection of possible errors and these must be developed in cooperation with the scientific and instrument communities. Data must move more quickly through the processing streams and become available to users. Despite the large volumes, there is high demand for on-line access to the entire archive. Strategies must be developed to meet this demand without large data requests swamping data servers. Part of this will involve providing data browse and selection tools that permit a user to refine their request to only the data of interest. Finally, there is an increasing need to use data from different sources to examine a variety of scientific and societal problems. Standard vocabularies for naming variables, instruments, methods, etc., must become widely used to allow easier interoperability of data.

Kelble, C.R. The effect of salinity on the plankton community of Florida Bay. Ph.D. thesis, University of Miami, Rosenstiel School of Marine and Atmospheric Science, 174 pp. (2010).

The greater Everglades ecosystem, including Florida Bay, has undergone significant anthropogenic manipulation over the past century. These actions resulted in a series of ecologically undesirable events in the Everglades ecosystem, prompting passage of the Comprehensive Everglades Restoration Plan (CERP). It is necessary to understand the variability in, and relationship between, salinity and ecology to fully evaluate the potential effects of CERP on Florida Bay. A seven-year dataset on surface salinity along with eleven-year and eight-year datasets on mesozooplankton and planktivorous fish were analyzed. Overall, mean Bay-wide salinity varied from a low of 24.2 just after the passing of Hurricane Irene in October 1999 to a high of 41.8 near the end of a drought period in July 2001. Bay-wide mean salinity exhibited dramatic decreases, up to 0.5 per day, whereas increases in bay-wide salinity were slower, with a maximum rate of 0.1 per day. Meteorological phenomena, such as tropical cyclones and ENSO, dramatically altered the salinity patterns of Florida Bay on interannual time scales. There was a large degree of spatial heterogeneity in salinity between sub-regions of Florida Bay due to differing freshwater sources and geomorphology. Mesozooplankton abundance displayed interannual variability and a positive correlation with salinity. Both of these features were also closely correlated with abundance of the dominant planktivorous fish, Anchoa mitchilli, indicating the importance of top-down control. The hypersaline periods appear to provide a refuge from predators, allowing mesozooplankton to increase in abundance during periods of increased physiological stress. The interaction between mesozooplankton and A. mitchilli, along with its correlation to salinity, was further investigated through the development of a mechanistic model of the populations in Florida Bay. The model indicated predation alone was insufficient to control mesozooplankton populations; rather, it was necessary to incorporate density-dependence utilizing a logistic prey population. With both mechanisms the model was able to replicate the observed interannual variability pattern and positive correlation between mesozooplankton and salinity. A preliminary management scenario evaluation suggests a two to six-fold difference in A. mitchilli and mesozooplankton populations between targeted and general salinity reductions. This suggests alternative freshwater management scenarios could produce drastically different ecological consequences.

Kelble, C.R., P.B. Ortner, G.L. Hitchcock, M.J. Dagg, and J.N. Boyer. Temporal and spatial variability of mesozooplankton in a shallow sub-tropical bay: Influence of top-down control. Estuaries and Coasts, 33(3):727-737 (2010).

Quantifying the relationship between mesozooplankton and water quality parameters identifies the factors that structure the mesozooplankton community and can be used to generate hypotheses regarding the mechanisms that control the mesozooplankton population and potentially the trophic network. To investigate this relationship, mesozooplankton and water quality data were collected in Florida Bay from 1994 to 2004. Three key characteristics were found in the mesozooplankton community structure: (1) there are significant differences between the four sub-regions of Florida Bay; (2) there is a break in May of 1997 with significant differences before and after this date; and (3) there is a positive correlation between mesozooplankton abundance and salinity. The latter two characteristics are closely correlated with predator abundance, indicating the importance of top-down control. Hypersaline periods appear to provide a refuge from predators, allowing mesozooplankton to increase in abundance despite the increased physiological stress.

Keul, N., J.W. Morse, R. Wanninkhof, D.K. Gledhill, and T.S. Bianchi. Carbonate chemistry dynamics of surface waters in the northern Gulf of Mexico. Aquatic Geochemistry, 16(3):337-351 (2010).

This paper presents the results of two cruises in the northern Gulf of Mexico in 2008 that investigated local and short-term factors influencing the carbonate chemistry dynamics and saturation state with respect to aragonite (OMEGA_aragonite) of surface seawater in this region. One cruise covered much of the northern half of the Gulf, and the other focused on the coastal zone west of the Atchafalaya Bay outlet of the Mississippi River--the region where the hypoxic dead zone occurs on the Louisiana shelf. Offshore waters (>100 m depth) exhibited only small variations in CO₂ fugacity (fCO₂), total alkalinity (TA), and OMEGA_aragonite. Values were close to those typically observed in subtropical Atlantic Ocean and Caribbean Sea waters of similar salinity. However, inner shelf waters (<50 m depth) exhibited large variations in fCO₂, TA, and OMEGA_aragonite that were not directly related to salinity or distance from the Mississippi River plume. Changes in TA values were not the result of simple mixing of end-member freshwater and seawater TA concentrations but exhibited a minimum in values near salinity of 25. This minimum could be the result of microbial recycling across salinity gradients, biological removal of alkalinity by formation of calcium carbonate or mixing of a third end-member with a low alkalinity such as Terrebonne Bay. All waters were supersaturated with respect to aragonite. Offshore waters had an average OMEGA_aragoniteof 3.86 with a standard deviation of only ±0.06 and inner shelf waters had a range in OMEGA_aragonite values from 3.9 to 9.7 with a median of 4.3. Shelf water OMEGA_aragonite values were elevated relative to the offshore as a consequence of both high TA input from Mississippi River and biological drawdown of CO₂. A dominant factor controlling OMEGA_aragonite distribution in offshore waters with relatively constant temperatures was fCO₂, with higher supersaturation occurring in areas with low fCO₂.

Kimball, S.K., M.S. Mulekar, S. Cummings, and J. Stamates. The University of South Alabama Mesonet and coastal observing system: A technical and statistical overview. Journal of Atmospheric and Oceanic Technology, 27(9):1417-1439 (2010).

The University of South Alabama Mesonet consists of 26 sites across the north-central Gulf of Mexico coast. Although the original purpose of the mesonet was monitoring landfalling tropical systems, meteorological data are collected and disseminated every 5 min year-round to serve a multitude of purposes, including weather forecasting, education, and research. In this paper a statistical analysis and like-sensor comparison demonstrates that variables, measured by different sensor types or by sensors at different heights, correlate well. The benefits of sensor redundancy are twofold, offering 1) backup sensors in the case of sensor failure during severe weather and 2) the ability to perform a large number of internal consistency checks for quality control purposes. An oceanographic compliment to the University of South Alabama Mesonet system, which was deployed by NOAAs Atlantic Oceanographic and Meteorological Laboratory (AOML) to measure surface waves and ocean currents in an area south of Mobile, Alabama, is described. A preliminary comparison of mesonet wind data and ocean wave data show good agreement, offering promising opportunities for future research.

Lee, S.-K., and C. Wang. Delayed advective oscillation of the Atlantic thermohaline circulation. Journal of Climate, 23(5):1254-1261 (2010).

A simple dynamic model is proposed to illustrate the multidecadal oscillation of the Atlantic Ocean thermohaline circulation. The proposed oscillation relies on alternating actions of positive and negative feedbacks, which are operated by a slow adjustment of the ocean circulation and the associated time delay in the advective flux response to a change in meridional density gradient. The key element of the oscillation is the time delay, which is conceptually related to the basin-crossing time of long Rossby waves in the high-latitude North Atlantic. For a sufficiently long time delay, the solution becomes unstable in some regions of model parameter space and oscillates with a period of approximately 2 times the delay time.

Lee, S.-K., C. Wang, and D.B. Enfield. On the impacts of central Pacific warming events on Atlantic tropical storm activity. Geophysical Research Letters, 37:L17702, doi:10.1029/2010GL044459, 5 pp. (2010).

A recent study by Kim et al. (2009) claim that central Pacific warming (CPW) events in 1969, 1991, 1994, 2002 and 2004 are associated with a greater-than-average frequency of tropical storms and increasing landfall potential along the Gulf of Mexico coast and Central America. Based on an independent data analysis of tropical cyclone activity in the five CPW years, it is shown here that only 1969, 2002, and 2004 were characterized with significantly greater-than-average cyclone activity in the Gulf of Mexico and Caribbean Sea, whereas 1991 and 1994 were characterized with significantly lower-than-average activity. Coincidently, the Atlantic warm pool (AWP) was significantly larger than average during 1969 and 2004, and significantly smaller than average during 1991 and 1994. By performing multiple sets of ensemble model experiments using the NCAR atmospheric general circulation model, it is shown here that the increased tropical storm frequency in 1969 and 2004 can be readily explained by a large AWP and the associated vertical wind shear reduction and enhanced moist convective instability in the main development region for Atlantic hurricanes, without invoking a remote influence from the tropical Pacific. Therefore, we conclude that it is premature to associate CPW events to an increasing frequency of cyclone activity in the Gulf of Mexico and Caribbean Sea.

Leidner, S.M., J. Ardizzone, J.C. Jusem, E. Brin, R.N. Hoffman, and R. Atlas. Ocean-surface wind impacts on hurricane forecasting: Regional and global examples. Proceedings, 14th Symposium on Integrated Observing and Assimilation Systems for the Atmosphere, Oceans, and Land Surface (IOAS-AOLS), Atlanta, GA, January 17-21, 2010. American Meteorological Society, Boston, 5 pp. (2010).

No abstract.

Levina, G.V., and M.T. Montgomery. A first examination of the helical nature of tropical cyclogenesis. Doklady Earth Sciences, 434(1):1285-1289 (2010).

No abstract.

Lorsolo, S., F.D. Marks, J.F. Gamache, and J.A. Zhang. Estimation and mapping of hurricane turbulent energy using airborne Doppler measurements. Monthly Weather Review, 138(9):3656-3670 (2010).

Hurricane turbulent kinetic energy (TKE) was computed using airborne Doppler measurements from the NOAA WP-3D tail radars and TKE data were retrieved for a variety of storms at different stages of their lifecycle. The geometry of the radar analysis coupled with the relatively small beam resolution at ranges <8 km allowed for the estimation of sub-kilometer turbulent processes. Two dimensional profiles of TKE were constructed and revealed that the strongest turbulence was in general located in convective regions such as the eyewall with magnitude often exceeding 15 m² s^-2, and in the boundary layer with values of 5-10 m² s^-2 in the lowest km. A correlation analysis showed that the strong turbulence was in general associated with strong horizontal shear of vertical and radial wind components in the eyewall and strong vertical shear of horizontal wind in the boundary layer. Mean vertical profiles of TKE decrease sharply above the hurricane boundary layer and level off at low magnitude for all regions outside the radius of maximum wind. The quality of the retrieval method was evaluated and showed very good agreement with TKE values directly calculated from the three-dimensional wind components of in-situ measurements. The method presented here provides a unique opportunity to assess hurricane turbulence throughout the storm, especially in high wind regions, and can be applied on extensive data sets of past and future airborne hurricane penetrations.

Lumpkin, R., and S. Elipot. Surface drifter pair spreading in the North Atlantic. Journal of Geophysical Research, 115:C12017, 20 pp. (doi:10.1029/2010JC006338) (2010).

This study examines spreading of surface drifter pairs deployed as part of the CLIVAR Mode Water Dynamic Experiment (CLIMODE) project in the Gulf Stream region. The spreading is resolved at hourly resolution and quantified by relative dispersion and finite-scale Lyapunov exponents. At scales from 1-3 km to 300-500 km, the dispersion follows Richardsons Law, indicating stirring by eddies comparable in scale to the pair separation distance. At larger scales, the spreading becomes a random walk described by a constant diffusivity. The behavior from 1-3 km to the local deformation radius is inconsistent with the enstrophy cascade of 2-D quasigeostrophic turbulence. To test various hypotheses for this result, drifter pair spreading is examined for pairs that were not launched together, pairs deployed in the eastern subtropical North Atlantic, and CLIMODE pairs subsampled to daily temporal resolution. Our results indicate the presence of significant energy at the submesoscale in the Gulf Stream region which flattens the wave number spectrum and dominates surface stirring at this scale range. Results in the less energetic subtropical eastern Atlantic are more equivocal.

Lumpkin, R., G. Goni, and K. Dohan. Surface currents. In State of the Climate in 2009, D.S. Arndt, M.O. Baringer, and M.R. Johnson (eds.). Bulletin of the American Meteorological Society, 91(6):65-66 (2010).

No abstract.

Luo, D., Z. Zhu, R. Ren, L. Zhong, and C. Wang. Spatial pattern and zonal shift of the North Atlantic Oscillation, Part I: A dynamical interpretation. Journal of the Atmospheric Sciences, 67(9):2805-2826 (2010).

This paper presents a possible dynamical explanation for why the North Atlantic Oscillation (NAO) pattern exhibits an eastward shift from the period 1958-77 (P1) to the period 1978-97 (P2) or 1998-2007 (P3). Firstly, the empirical orthogonal function analysis of winter-mean geopotential heights during P1, P2, and P3 reveals that the NAO dipole anomaly exhibits a northwest-southeast (NW-SE) tilting during P1, but a northeast-southwest (NE-SW) tilting during P2 (P3). The NAO pattern, especially its northern center, undergoes a more pronounced eastward shift from P1 to P2. The composite calculation of NAO events during P1 and P2 also indicates that the negative (positive) NAO phase dipole anomaly can indeed exhibit such a NW-SE (NE-SW) tilting. Secondly, a linear Rossby wave formula derived in a slowly varying basic flow with a meridional shear is used to qualitatively show that the zonal phase speed of the NAO dipole anomaly is larger (smaller) in higher latitudes and smaller (larger) in lower latitudes during the life cycle of the positive (negative) NAO phases because the core of the Atlantic jet is shifted to the north (south). Such a phase speed distribution tends to cause the different movement speeds of the NAO dipole anomaly at different latitudes, thus resulting in the different spatial tilting of the NAO dipole anomaly depending upon the phase of the NAO. The zonal displacement of the northern center of the NAO pattern appears to be more pronounced because the change of the mean flow between two phases of the NAO is more distinct in higher latitudes than in lower latitudes. In addition, a weakly nonlinear analytical solution, based on the assumption of the scale separation between the NAO anomaly and transient synoptic-scale waves, is used to demonstrate that an eastward shift of the Atlantic storm track eddy activity that is associated with the eastward extension of the Atlantic jet stream is a possible cause of the whole eastward shift of the center of action of the NAO pattern during P2 (P3).

Luo, D., L. Zhong, R. Ren, and C. Wang. Spatial pattern and zonal shift of the North Atlantic Oscillation, Part II: Numerical experiments. Journal of the Atmospheric Sciences, 67(9):2827-2853 (2010).

In this part, the spatial evolution of an initial dipole anomaly in a prescribed jet is at first investigated by numerically solving linear and nonlinear models without forcing in order to examine how the spatial pattern of a dipole anomaly depends upon the meridional distribution of a specified jet. It is shown that in a linear experiment, an initial symmetric dipole anomaly in the meridional direction can evolve into a northeast-southwest (NE-SW) or northwest-southeast (NW-SE) tilted dipole structure if the core of this jet is in higher latitudes (the north) or in lower latitudes (the south). This is in agreement with the result predicted by the linear Rossby wave theory in a slowly varying media. The conclusion is also held for the nonlinear and unforced experiment. NAO events are then reproduced in a fully nonlinear barotropic model with a wavemaker that mimics the Atlantic storm track eddy activity. In the absence of topography the spatial tilting of the eddy-driven NAO pattern is found to be independent of the NAO phase. The eddy-driven NAO pattern for the positive (negative) phase can exhibit a NE-SW (NW-SE) tilting only when the core of a prescribed jet prior to the NAO is confined in the higher (lower) latitude region. But, in the presence of the wavenumber-two topography (two oceans and continents) in the Northern Hemisphere the spatial tilting of the eddy-driven NAO dipole anomaly can be dependent on the NAO phase. Even when the specified basic flow prior to the NAO is uniform the eddy-driven positive (negative) NAO phase dipole anomaly can also show a NE-SW (NW-SE) tilting because the northward (southward) shift of the excited westerly jet can occur in the presence of topography. In addition, it is found that when the wavemaker is closer to the position of the initial NAO, the eddy-driven positive (negative) NAO phase pattern can display a whole eastward shift and a more distinct NE-SW (NW-SE) tilting. This thus explains why the first empirical orthogonal function of the NAO pattern observed during 1998-2007 exhibits a more pronounced NE-SW tilting than that during 1978-97. It appears that the latitudinal shift of the jet, the large-scale topography and the zonal position of the Atlantic storm track eddy activity are three important factors for controlling the spatial tilting and zonal shift of eddy-driven NAO dipole anomalies.

Majumdar, S.J., K.J. Sellwood, D. Hodyss, Z. Toth, and Y. Song. Characteristics of target areas selected by the Ensemble Transform Kalman Filter for medium-range forecasts of high-impact winter weather. Monthly Weather Review, 138(7):2803-2824 (2010).

The characteristics of target locations of tropospheric wind and temperature identified by a modified version of the ensemble transform Kalman filter (ETKF), in order to reduce 0-7-day forecast errors over North America, are explored from the perspective of a field program planner. Twenty cases of potential high-impact weather over the continent were investigated, using a 145-member ensemble comprising perturbations from NCEP, ECMWF, and the Canadian Meteorological Centre (CMC). Multiple targets were found to exist in the midlatitude storm track. In half of the cases, distinctive targets could be traced upstream near Japan at lead times of 4-7 days. In these cases, the flow was predominantly zonal and a coherent Rossby wave packet was present over the northern Pacific Ocean. The targets at the longest lead times were often located within propagating areas of baroclinic energy conversion far upstream. As the lead time was reduced, these targets were found to diminish in importance, with downstream targets corresponding to a separate synoptic system gaining in prominence. This shift in optimal targets is sometimes consistent with the radiation of ageostrophic geopotential fluxes and transfer of eddy kinetic energy downstream, associated with downstream baroclinic development. Concurrently, multiple targets arise due to spurious long-distance correlations in the ETKF. The targets were least coherent in blocked flows, in which the ETKF is known to be least reliable. The effectiveness of targeting in the medium range requires evaluation, using data such as those collected during the winter phase of The Observing System Research and Predictability Experiment (THORPEX) Pacific Asian Regional Field Campaign (T-PARC) in 2009.

Manzello, D.P. Coral growth with thermal stress and ocean acidification: Lessons from the eastern tropical Pacific. Coral Reefs, 29(3):749-758 (2010).

The rapid growth of scleractinian corals is responsible for the persistence of coral reefs through time. Coral growth rates have declined over the past 30 years in the western Pacific, Indian, and North Atlantic Oceans. The spatial scale of this decline has led researchers to suggest that a global phenomenon like ocean acidification may be responsible. A multi-species inventory of coral growth from Pacific Panama confirms that declines have occurred in some, but not all species. Linear extension declined significantly in the most important reef builder of the eastern tropical Pacific, Pocillopora damicornis, by nearly one-third from 1974 to 2006. The rate of decline in skeletal extension for P. damicornis from Pacific Panama (0.9% year^-1) was nearly identical to massive Porites in the Indo-Pacific over the past 20-30 years (0.89-1.23% year^-1). The branching pocilloporid corals have shown an increased tolerance to recurrent thermal stress events in Panama, but appear to be susceptible to acidification. In contrast, the massive pavonid corals have shown less tolerance to thermal stress, but may be less sensitive to acidification. These differing sensitivities will be a fundamental determinant of eastern tropical Pacific coral reef community structure with accelerating climate change that has implications for the future of reef communities worldwide.

Manzello, D.P. Ocean acidification hotspots: Spatiotemporal dynamics of the seawater CO₂-system from eastern Pacific coral reefs. Limnology and Oceanography, 55(1):239-248 (2010).

Seawater CO₂ system dynamics were assessed from eastern Pacific reef sites in Panama over five consecutive years (2003-2008) and twice in the Galapagos Islands (2003 and 2009). The seawater CO₂ system was highly variable in time and space, but was explained by physical forcing from meteorological (seasonal rainfall) and oceanographic (upwelling, tides) processes interacting with diurnal reef metabolism. Galapagos coral reef communities are naturally exposed to the highest ambient partial pressure of CO₂ (pCO₂) and lowest aragonite saturation (OMEGA_arag) values documented for any coral reef environment to date. During upwelling in the Galapagos, mean pCO₂ and mean OMEGA_arag at five different sites ranged from 53.1 to 73.5 Pa and 2.27 to 2.86, respectively. Values of pCO₂ and OMEGA_arag ranged from 21.0 to 48.7 Pa and 2.47 to 4.18, respectively, on the Saboga Reef in the seasonally upwelling Gulf of Panama, with the highest pCO₂ and lowest OMEGA_arag values occurring during upwelling. The Uva Reef, in the nonupwelling Gulf of Chiriqui of Pacific Panama, had mean OMEGA_arag values that were always significantly greater than those at the Saboga Reef. Diurnal changes in the seawater CO₂ system from reef metabolism on the Uva Reef were magnified at low tide and highly significant differences were measured over depths as shallow as 15 m because of the shallow thermocline that is pervasive throughout the eastern Pacific. These naturally high-CO₂ reefs persist near the OMEGA_arag distributional threshold for coral reefs and are thus expected to be the first and most affected by ocean acidification.

McPhaden, M.J., K. Ando, B. Bourles, H.P. Freitag, R. Lumpkin, Y. Masumoto, V.S.N. Murty, P. Nobre, M. Ravichandran, J. Vialard, D. Vousden, and W. Yu. The global tropical moored buoy array. In OceanObs09: Sustained Ocean Observations and Information for Society (Volume 2), J. Hall, D.E. Harrison, and D. Stammer (eds.). European Space Agency Publication, WPP-306, 17 pp. (2010).

This paper describes the Global Tropical Moored Buoy Array (GTMBA), which is a multi-national effort to provide data in real time for climate research and forecasting. Components of the global array include the Tropical Atmosphere Ocean/Triangle Trans-Ocean Buoy Network (TAO/TRITON) in the Pacific, the Prediction and Research Moored Array in the Tropical Atlantic (PIRATA), and the Research Moored Array for African-Asian-Australian Monsoon Analysis and Prediction (RAMA) in the Indian Ocean. The phenomena of primary interest span intraseasonal-to-decadal and longer timescales, including: (1) El Niño/Southern Oscillation and its decadal modulation in the Pacific; (2) the meridional gradient mode and equatorial warm events in the Atlantic; (3) the Indian Ocean Dipole; (4) the mean seasonal cycle, including the Asian, African, Australian, and American monsoons; (5) the intraseasonal Madden-Julian Oscillation, which originates in the Indian Ocean but affects all three ocean basins; and (6) trends that may be related to global warming. Sustained, systematic and comprehensive observations are necessary to advance knowledge of critical processes that govern climate dynamics originating in the tropics. Observations are also needed to develop, initialize, and validate climate forecast models that can be used for advance warning of natural hazards and for many other societal benefits. A global tropical perspective is required not only because of the range and complexity of tropical phenomena that affect the climate system, but also because of basin-to-basin interactions that affect the evolution of climatic fluctuations. This paper reviews expansions and enhancements of moored buoy measurement efforts in the tropics since the October 1999 OceanObs99 Conference in San Rafael, France. We will also highlight major scientific advances enabled by the Global Tropical Moored Buoy Array over the past 10 years.

Meinen, C.S., M.O. Baringer, and R.F.Garcia. Florida Current transport variability: An analysis of annual and longer period signals. Deep-Sea Research, Part I, 57(7):835-846 (2010).

More than forty years of Florida Current transport estimates are combined to study annual and longer-term variability in this important component of the MOC and subtropical gyre. A detailed analysis with error estimates illustrates the difficulties in extracting annual and longer time scale variability given the strong higher frequency energy present. The annual cycle represents less than 10% of the total Florida Current transport variance in a 16-yr segment of the record, while interannual (13-42 month) variability represents only 13% of the total and periods longer than 42 months represent less than 10% of the total. Given the observed high frequency variability of the Florida Current, in order to get a monthly mean that is accurate to within 0.5 Sv (one standard error level) more than 20 daily observations are needed. To obtain an estimate of the annual climatology that is accurate to within 20% of its own standard deviation, at least 24 yr of data are needed. More than 40 observations spread throughout a year are required to obtain an annual mean that is accurate to within 0.5 Sv. Despite these daunting data requirements, there is sufficient data now to evaluate both the annual cycle of the Florida Current transport with a high degree of accuracy and to begin to determine the longer period transport variability. Comparison of the Florida Current, NAO, and wind stress curl records shows that a recently described Sverdrup-based mechanism explains a significant fraction of the long-period variability primarily during the 1986-1998 time window, with other mechanisms clearly dominating before and after.

Metzl, N., A. Corbiere, G. Reverdin, A. Lenton, T. Takahashi, A. Olsen, T. Johannessen, D. Pierrot, R. Wanninkhof, S.R. Olafsdottir, J. Olafsson, and M. Ramonet. Recent acceleration of the sea surface fCO₂ growth rate in the North Atlantic subpolar gyre (1993-2008) revealed by winter observations. Global Biogeochemical Cycles, 24:GB4004, doi:10.1029/2009GB003658, 13 pp. (2010).

Recent studies based on ocean and atmospheric carbon dioxide (CO₂) observations, suggesting that the ocean carbon uptake has been reduced, may help explain the increase in the fraction of anthropogenic CO₂ emissions that remain in the atmosphere. Is it a response to climate change or a signal of ocean natural variability or both? Regional process analyses are needed to follow the ocean carbon uptake and to enable better attributions of the observed changes. Here, we describe the evolution of the surface ocean CO₂ fugacity (fCO₂^oc) over the period 1993-2008 in the North Atlantic subpolar gyre (NASPG). This analysis is based primarily on observations of dissolved inorganic carbon (DIC) and total alkalinity (TA) conducted at different seasons in the NASPG between Iceland and Canada. The fCO₂^oc trends based on DIC and TA data are also compared with direct fCO₂^oc measurements obtained between 2003 and 2007 in the same region. During winters 1993-2003, the fCO₂^oc growth rate was 3.7 (±0.6) µatm yr^-1, higher than in the atmosphere, 1.8 (±0.1) µatm yr^-1. This translates to a reduction of the ocean carbon uptake primarily explained by sea surface warming, up to 0.24 (±0.04) °C yr^-1. This warming is a consequence of advection of warm water northward from the North Atlantic into the Irminger basin, which occurred as the North Atlantic Oscillation (NAO) index moved into a negative phase in winter 1995/1996. In winter 2001-2008, the fCO₂^oc rise was particularly fast, between 5.8 (±1.1) and 7.2 (±1.3) µatm yr^-1 depending on the region, more than twice the atmospheric growth rate of 2.1 (±0.2) µatm yr^-1, and in the winter of 2007-2008 the area was supersaturated with CO₂. As opposed to the 1990s, this appears to be almost entirely due to changes in seawater carbonate chemistry, the combination of increasing DIC and decreasing of TA. The rapid fCO₂^oc increase was not only driven by regional uptake of anthropogenic CO₂ but was also likely controlled by a recent increase in convective processes-vertical mixing in the NASPG and cannot be directly associated with NAO variability. The fCO₂^oc increase observed in 2001-2008 leads to a significant drop in pH of -0.069 (±0.007) decade^-1.

Monteiro, P.M.S., U. Schuster, M. Hood, A. Lenton, M. Metzl, A. Olsen, K. Rogers, C. Sabine, T. Takahashi, B. Tilbrook, J. Yoder, R. Wanninkhof, and A.J. Watson. A global sea surface carbon observing system: Assessment of changing sea surface CO₂ and air-sea CO₂ fluxes. In OceanObs09: Sustained Ocean Observations and Information for Society (Volume 2), J. Hall, D.E. Harrison, and D. Stammer (eds.). European Space Agency Publication, WPP-306, 13 pp. (2010).

No abstract.

Montgomery, M.T., and R.K. Smith. On an analytical model for the rapid intensification of tropical cyclones. Quarterly Journal of the Royal Meteorological Society, 136(647):549-551 (2010).

Stimulated by recent developments in understanding tropical cyclones, we offer an evaluation of an analytical model that has been proposed to explain the rapid intensification of these storms. We articulate a number of concerns with this model, including the neglect of both the vertical momentum equation and the thermodynamic equation, and conclude that it falls a little short of achieving its stated aims.

Montgomery, M.T., Z. Wang, and T.J. Dunkerton. Coarse, intermediate, and high resolution numerical simulations of the transition of a tropical wave critical layer to a tropical storm. Atmospheric Chemistry and Physics, 10(22):10803-10827 (doi:10.5194/acp-10-10803-2010) (2010).

Recent work has hypothesized that tropical cyclones in the deep Atlantic and eastern Pacific basins develop from within the cyclonic Kelvin cat's eye of a tropical easterly wave critical layer located equatorward of the easterly jet axis. The cyclonic critical layer is thought to be important to tropical cyclogenesis because its cat's eye provides (i) a region of cyclonic vorticity and weak deformation by the resolved flow, (ii) containment of moisture entrained by the developing flow and/or lofted by deep convection therein, (iii) confinement of mesoscale vortex aggregation, (iv) a predominantly convective type of heating profile, and (v) maintenance or enhancement of the parent wave until the developing proto-vortex becomes a self-sustaining entity and emerges from the wave as a tropical depression. This genesis sequence and the overarching framework for describing how such hybrid wave-vortex structures become tropical depressions/storms is likened to the development of a marsupial infant in its mother's pouch, and for this reason has been dubbed the "marsupial paradigm." Here, we conduct the first multi-scale test of the marsupial paradigm in an idealized setting by revisiting the Kurihara and Tuleya problem examining the transformation of an easterly wave-like disturbance into a tropical storm vortex using the WRF model. An analysis of the evolving winds, equivalent potential temperature, and relative vertical vorticity is presented from coarse (28 km), intermediate (9 km), and high resolution (3.1 km) simulations. The results are found to support key elements of the marsupial paradigm by demonstrating the existence of a rotationally-dominant region with minimal strain/shear deformation near the center of the critical layer pouch that contains strong cyclonic vorticity and high saturation fraction. This localized region within the pouch serves as the "attractor" for an upscale "bottom up" development process while the wave pouch and proto-vortex move together. Implications of these findings are discussed in relation to an upcoming field experiment for the most active period of the Atlantic hurricane season in 2010 that is to be conducted collaboratively between the National Oceanic and Atmospheric Administration (NOAA), the National Science Foundation (NSF), and the National Aeronautics and Space Adminstration (NASA).

Montgomery, M.T., L.L. Lussier, R.W. Moore, and Z. Wang. The genesis of Typhoon Nuri as observed during the Tropical Cyclone Structure 2008 (TCS-08) field experimentPart 1: The role of the easterly wave critical layer. Atmospheric Chemistry and Physics, 10(20):9879-9900 (2010).

An observational and real-time model forecast study of the genesis of Typhoon Nuri during the Tropical Cyclone Structure 2008 (TCS-08) field campaign in the western North Pacific sector is presented. Analysis and observational data show that the surrounding base state is an easterly trade wind flow and the precursor disturbance to Typhoon Nuri is an easterly wave that originates in the ITCZ in the Central Pacific. This disturbance can be tracked more than 10 days prior to tropical storm formation. An overview of the field data is presented here using a newly proposed dynamical framework for tropical cyclone formation within the critical layer of an easterly wave. Despite propagating through a hostile environment ripe with strong vertical wind shear and relatively dry air, the easterly wave critical layer protects the proto-vortex and allows it to gestate until it reaches a more favorable environment. Within this protective Kelvin cats eye flow located within the waves critical layer existed a sweet spot, defined as the intersection between the wave trough and critical latitude, which is the preferred location for tropical cyclogenesis. Global Forecast System Final Analyses and IR satellite imagery, which shows convective bands wrapping around the sweet spot as genesis nears, confirm that this sweet spot is the location where Typhoon Nuri's dominant low-level circulation emerges. United States Air Force C130 and Naval Research Laboratory P3 research flights on 16 and 17 August collected flight-level, dropwindsonde, and Doppler radar data that allowed an evaluation of the dynamic and thermodynamic processes within the cats eye circulation. The dropwindsonde analyses identifies the precursor easterly wave disturbance on 16 August and identifies an area of weak low-level cyclonic circulation on 17 August. Real-time forecasts were produced using operational global prediction model data to support scientific missions during TCS-08. These forecasts were found to be useful in flight planning discussions and predicted Typhoon Nuri's eventual genesis latitude within 1.5 degrees 72 h in advance.

Munoz, E. The human side of climate change. SACNAC News, 12(2):18-19, 32 (2010).

No abstract.

Munoz, E., C. Wang, and D. Enfield. The Intra-Americas Sea springtime surface temperature anomaly dipole as fingerprint of remote influences. Journal of Climate, 23(1):43-56 (2010).

The influence of teleconnections on the Intra-Americas Sea (IAS; Gulf of Mexico and Caribbean Sea) has been mostly analyzed from the perspective of the El Niño-Southern Oscillation (ENSO) on the Caribbean Sea (the latter being an extension of the tropical North Atlantic). This emphasis has overlooked: (1) the influence of other teleconnections on the IAS; and (2) which teleconnections affect the Gulf of Mexico climate variability. In this study, we analyze the different fingerprints that major teleconnection patterns have on the IAS during boreal spring. Indices of teleconnection patterns are regressed and correlated to observations of oceanic temperature and atmospheric data from reanalyses and observational data sets. We find that the Pacific teleconnection patterns that influence the IAS SSTs do so affecting the Gulf of Mexico in an opposite manner to the Caribbean Sea. These Pacific climate patterns analyzed are the Pacific North American (PNA) teleconnection, the Pacific Decadal Oscillation (PDO), and the ENSO. The North Atlantic Oscillation (NAO) is related to a lesser degree with the north-south SST anomaly dipole than are Pacific teleconnection patterns. We also find that the IAS influence from the midlatitude Pacific affects mostly the Gulf of Mexico, whereas the influence from the tropical Pacific affects mostly the Caribbean Sea. Therefore, the combination of a warm ENSO event and a positive PNA event induces a strong IAS SST anomaly dipole between the Gulf of Mexico and the Caribbean Sea during spring. By calculating an index that represents the IAS SST anomaly dipole, we find that the dipole forms mostly in response to changes in the air-sea heat fluxes. In the Gulf of Mexico the dominant mechanisms are the air-sea differences in humidity and temperature. The changes in shortwave radiation also contribute to the dipole of net air-sea heat flux. The changes in shortwave radiation arise, in part, by the cloudiness triggered by the air-sea differences in humidity, and also by the changes in the convection cell that connects the Amazon basin to the IAS. Weaker Amazon convection (e.g., in the event of a warm ENSO event) reduces the subsidence over the IAS and henceforth the IAS cloudiness increases (and the shortwave radiation decreases). This study contributes to a greater understanding of how the IAS is influenced by different Pacific and Atlantic teleconnections.

Park, G.-H., R. Wanninkhof, and J. Trinanes. Procedures to create near real-time seasonal air-sea CO₂ flux maps. NOAA Technical Memorandum, OAR AOML-98, 14 pp. (2010).

Seasonal air-sea carbon dioxide (CO₂) flux maps were calculated from wind speed data and the difference in CO₂ partial pressure between surface seawater (pCO_2SW) and the overlying atmosphere. To infer the seasonal variability of global net air-sea CO₂ fluxes over the last three decades, we derived the optimum subannual relationships between pCO_2SW and the sea surface temperature (SST). These optimum subannual relationships accounted for the variations between pCO_2SW and SST and showed significantly better correlations than previous relationships with fixed monthly boundaries. The derived algorithms were then applied to high-resolution SST data to yield changes in pCO_2SW on a monthly basis. The pCO_2SW values were also combined with a gas transfer velocity estimate derived from high resolution wind products to estimate seasonal fluxes. The seasonal fluxes that are calculated with a three- to six-month lag from real-time can be obtained at http://cwcgom.aoml.noaa.gov/erddap/griddap/aomlcarbonfluxes.graph. Here, we describe in detail the procedures and uncertainties of this product.

Park, G.-H., R. Wanninkhof, S.C. Doney, T. Takahashi, K. Lee, R.A. Feely, C.L. Sabine, J. Trinanes, and I.D. Lima. Variability of global net sea-air CO₂ fluxes over the last three decades using empirical relationships. Tellus B, 62(5):352-368 (doi: 10.1111/j.1600-0889.2010.00498.x) (2010).

The interannual variability of net sea-air CO₂ flux for the period 1982-2007 is obtained from a diagnostic model using empirical subannual relationships between climatological CO₂ partial pressure in surface seawater (pCO_2SW) and sea surface temperature (SST), along with interannual changes in SST and wind speed. These optimum subannual relationships show significantly better correlation between pCO_2SW and SST than the previous relationships using fixed monthly boundaries. Our diagnostic model yields an interannual variability of ±0.14 PgC yr^-1 (1 sigma) with a 26-year mean of -1.48 PgC yr^-1. The greatest interannual variability is found in the equatorial Pacific, and significant variability is also found at northern and southern high-latitudes, depending in part, on which wind product is used. We provide an assessment of our approach by applying it to pCO_2SW and SST output from a prognostic global biogeochemical ocean model. Our diagnostic approach applied to this model output shows reasonable agreement with the prognostic model net sea-air CO₂ fluxes in terms of magnitude and phase of variability, suggesting that our diagnostic approach can capture much of the observed variability on regional to global scale. A notable exception is that our approach shows significantly less variability than the prognostic model in the Southern Ocean.

Peng, T.-H., and R. Wanninkhof. Increase of anthropogenic CO₂ in the Atlantic Ocean in the last two decades. Deep-Sea Research, Part I, 57(6):755-770 (2010).

Data from the first systematic survey of inorganic carbon parameters on a global scale, the GEOSECS program, are compared with those collected during WOCE/JGOFS to study the changes in carbon and other geochemical properties, and anthropogenic CO₂ increase in the Atlantic Ocean from the 1970s to the early 1990s. This first data-based estimate of CO₂ increase over this period was accomplished by adjusting the GEOSECS data set to be consistent with recent high-quality carbon data. Multiple Linear Regression (MLR) and extended Multiple Linear Regression (eMLR) analyses to these carbon data are applied by regressing DIC with potential temperature, salinity, AOU, silica, and PO₄ in three latitudinal regions for the western and eastern basins in the Atlantic Ocean. The results from MLR (and eMLR provided in parentheses) indicate that the mean anthropogenic CO₂ uptake rate in the western basin is 0.70 (0.53) mol m^-2 yr^-1 for the region north of 151°N; 0.53 (0.36) mol m^-2 yr^-1 for the equatorial region between 151°N and 151°S; and 0.83 (0.35) mol m^-2 yr^-1 in the South Atlantic south of 151°S. For the eastern basin an estimate of 0.57 (0.45) m^-2 yr^-1 is obtained for the equatorial region, and 0.28 (0.34) mol m^-2 yr^-1 for the South Atlantic south of 151°S. The results of using eMLR are systematically lower than those from MLR method in the western basin. The anthropogenic CO₂ increase is also estimated in the upper thermocline from salinity normalized DIC after correction for AOU along the isopycnal surfaces. For these depths the results are consistent with the CO₂ uptake rates derived from both MLR and eMLR methods.

Perez, R.C., M.F. Cronin, and W.S. Kessler. Tropical cells and secondary circulation near the northern front of the equatorial Pacific cold tongue. Journal of Physical Oceanography, 40(9):2091-2106 (2010).

Shipboard measurements and a model are used to describe the mean structure of meridional-vertical tropical cells (TCs) in the central equatorial Pacific, and a secondary circulation associated with the northern front of the cold tongue. The shape of the front is convoluted by the passage of tropical instability waves (TIWs). When velocities are averaged in a coordinate system centered on the instantaneous position of the northern front, the measurements show a near-surface minimum in northward flow north of the surface front (convergent flow near the front). This convergence and inferred downwelling extend below the surface mixed layer, tilt poleward with depth, and are meridionally bounded by regions of divergence and upwelling. Similarly, the model shows that on average, surface cold tongue water moves northward towards the frontal region and dives below tilted front, while subsurface water north of the front moves southward towards the front, upwells, and then moves northward in the surface mixed layer. The model is used to demonstrate that this mean quasi-adiabatic secondary circulation is not a frozen field that migrates with the front, but is instead highly dependent on the phase of the TIWs: southward-upwelling flow on the warm side of the front tends to occur when the front is displaced southward, while northward-downwelling flow on the cold side of the front occurs when the front is displaced northward. Consequently, when averaged in geographic coordinates, the observed and simulated TCs appear to be equatorially-asymmetric, and show little trace of a secondary circulation near the mean front.

Pierrot, D., P. Brown, S. Van Heuven, T. Tanhua, U. Schuster, R. Wanninkhof, and R.M. Key. CARINA TCO₂ data in the Atlantic Ocean. Earth System Science Data, 2(2):177-187 (2010).

Water column data of carbon and carbon-relevant hydrographic and hydrochemical parameters from 188 cruises in the Arctic Mediterranean Seas, Atlantic and Southern Ocean have been retrieved and merged in a new data base: the CARINA (CARbon IN the Atlantic) Project. These data have gone through rigorous quality control (QC) procedures so as to improve the quality and consistency of the data as much as possible. Secondary quality control, which involved objective study of data in order to quantify systematic differences in the reported values, was performed for the pertinent parameters in the CARINA data base. Systematic biases in the data have been tentatively corrected in the data products. The products are three merged data files with measured, adjusted and interpolated data of all cruises for each of the three CARINA regions (Arctic Mediterranean Seas, Atlantic and Southern Ocean). Ninety-eight cruises were conducted in the Atlantic defined as the region south of the Greenland-Iceland-Scotland Ridge and north of about 30°S. Here we report the details of the secondary QC which was done on the total dissolved inorganic carbon (TCO₂) data and the adjustments that were applied to yield the final data product in the Atlantic. Procedures of quality control, including crossover analysis between stations and inversion analysis of all crossover data, are briefly described. Adjustments were applied to TCO₂ measurements for 17 of the cruises in the Atlantic Ocean region. With these adjustments, the CARINA database is consistent both internally as well as with GLODAP data, an oceanographic data set based on the WOCE Hydrographic Program in the 1990s, and is now suitable for accurate assessments of, for example, regional oceanic carbon inventories, uptake rates, and model validation.

Posselt, D.J., and T. Vukicevic. Robust characterization of model physics uncertainty for simulations of deep moist convection. Monthly Weather Review, 138(5):1513-1535 (2010).

This study explores the functional relationship between model physics parameters and model output variables for the purpose of (1) characterizing the sensitivity of the simulation output to the model formulation and (2) understanding model uncertainty so that it can be properly accounted for in a data assimilation framework. A Markov chain Monte Carlo algorithm is employed to examine how changes in cloud microphysical parameters map to changes in output precipitation, liquid and ice water path, and radiative fluxes for an idealized deep convective squall line. Exploration of the joint probability density function (PDF) of parameters and model output state variables reveals a complex relationship between parameters and model output that changes dramatically as the system transitions from convective to stratiform. Persistent nonuniqueness in the parameter-state relationships is shown to be inherent in the construction of the cloud microphysical and radiation schemes and cannot be mitigated by reducing observation uncertainty. The results reinforce the importance of including uncertainty in model configuration in ensemble prediction and data assimilation, and they indicate that data assimilation efforts that include parameter estimation would benefit from including additional constraints based on known physical relationships between model physics parameters to render a unique solution.

Pouliquen, S., C. Schmid, A. Wong, S. Guinehut, and M. Belbeoch. ARGO data management. In OceanObs09: Sustained Ocean Observations and Information for Society (Volume 2), J. Hall, D.E. Harrison, and D. Stammer (eds.). European Space Agency Publication, WPP-306, 5 pp. (2010).

During the past decade Argo has revolutionized the distribution of ocean data within the research community. People used to go to sea, acquire data, process them, submit one or more publications using these data and finally submit them to their national center that periodically transfers the new data to a World Data Center. WOCE had managed to reduce this exclusivity delay to about 2 years. With Argo, it was stated since the beginning that the data will be freely accessible in real-time both on GTS and Internet to serve the meteorological and oceanographic communities in operational and research capacities. Thanks to a great collaboration between the contributing teams, Argo managed to set up efficient and homogeneous data processing in real-time and in delayed-mode, as well as easy access through two Global Data Centers located in USA and France. Similar data system organization has then been endorsed by other components of the GOOS observing system.

Powell, M.D. Observing and analyzing the near-surface wind field in tropical cyclones. In Global Perspectives on Tropical Cyclones: From Science to Mitigation, J.C.L. Chan and J.D. Kepert (eds.). World Scientific Publishing Company, 2nd edition, 177-199 (2010).

This paper describes the current state of the art in measuring and analyzing surface winds in tropical cyclones. Observing platforms and strategies will be reviewed, along with their advantages and limitations.

Powell, M.D., S.T. Murillo, P.P. Dodge, E.W. Uhlhorn, J.F. Gamache, V. Cardone, A. Cox, S. Otero, N. Carrasco, B. Annane, and R. St. Fleur. Reconstruction of Hurricane Katrina's wind fields for storm surge and wave hindcasting. Ocean Engineering, 37(1):26-36 (2010).

As the most costly U.S. natural disaster in history, Hurricane Katrina fostered the IPET forensic study to better understand the event. All available observations from several hundred space-, land-, sea-, and aircraft-based measurement platforms were gathered and processed to a common framework for height, exposure, and averaging time, to produce a series of wind field snapshots at 3 h intervals to depict the wind structure of Katrina when in the Gulf of Mexico. The stepped-frequency microwave radiometer was calibrated against GPS sondes to establish the upper range of the instrument and then used to determine the wind field in the storm's core region in concert with airborne Doppler radar winds adjusted to the surface from near the top of the PBL (500 m). The SFMR data were used to develop a method to estimate surface winds from 3 km level reconnaissance aircraft observations, taking into consideration the observed azimuthal variation of the reduction factor. The SFMR method was used to adjust reconnaissance flight-level measurements to the surface in the core region when SFMR and Doppler winds were not available. A variety of coastal and inland mesonet data were employed, including portable towers deployed by Texas Tech University, University of Louisiana at Monroe, and the Florida Coastal Monitoring Program, as well as fixed mesonet stations from Louisiana State Universities Marine Consortium, University of Southern Mississippi, and Agricultural Networks from Louisiana, Mississippi, and Alabama, and the Coastal Estuarine Network of Alabama and Mississippi. Also included were land- (WSR-88D VAD and GBVTD, ASOS, Metar, LLWAS, HANDAR), space- (QuikScat, GOES cloud drift winds, WindSat), and marine- (GPS sondes, Buoys, C-MAN, ships) platforms. The wind fields serve as an analysis of record and were used to provide forcing for wave and storm surge models to produce hindcasts of water levels in the vicinity of flood control structures.

Reed, D.A., M.D. Powell, and J.M. Westerman. Energy infrastructure damage analysis for Hurricane Rita. Natural Hazards Review, 11(3):102-109 (2010).

In 2005, Hurricane Rita caused significant damage to the energy infrastructure in the Gulf of Mexico region. In the context of this investigation, the energy infrastructure refers to the offshore oil platforms, refineries, and gasoline supply stations in the region, often referred to as the petroleum infrastructure, the natural gas supply lines, and the delivery of electric power. In this paper, we examine the structural damage to the networks as defined by restoration, resilience, and fragility with a focus on the analysis of the electric power delivery disruptions. Our concern is not on the evaluation of risk, but rather to provide those who assess hurricane risk with relevant structural damage prediction models. We provide correlations of hurricane wind speed data with outages. We conclude that high winds alone can create significant damage to the energy infrastructure system.

Riemer, M., M.T. Montgomery, and M.E. Nicholls. A new paradigm for intensity modification of tropical cyclones: Thermodynamic impact of vertical wind shear on the inflow layer. Atmospheric Chemistry and Physics, 10(7):3163-3188 (2010).

An important roadblock to improved intensity forecasts for tropical cyclones (TCs) is our incomplete understanding of the interaction of a TC with the environmental flow. In this paper, we re-visit the canonical problem of a TC in vertical wind shear on an f-plane. A suite of numerical experiments is performed with intense TCs in moderate to strong vertical shear. We employ a set of simplified model physics, a simple bulk aerodynamic boundary layer scheme and warm rain microphysics, to foster better understanding of the dynamics and thermodynamics that govern the modification of TC intensity. In all experiments the TC is resilient to shear but significant differences in the intensity evolution occur. The ventilation of the TC core with dry environmental air at mid-levels and the dilution of the upper-level warm core are two prevailing hypotheses for the adverse effect of vertical shear on storm intensity. Here we propose an alternative and arguably more effective mechanism for how cooler and drier (lower theta_e) air, anti-fuel for the TC power machine, can enter the core region of the TC. Strong and persistent, shear-induced downdrafts flux low theta_e air into the boundary layer from above, significantly depressing the theta_e values in the storm's inflow layer. Air with lower theta_e values enters the eyewall updrafts, considerably reducing eyewall theta_e values in the azimuthal mean. When viewed from the perspective of an idealized Carnot-cycle heat engine, a decrease of storm intensity can thus be expected. Although the Carnot cycle model is, if at all, only valid for stationary and axisymmetric TCs, a close association of the downward transport of low theta_e into the boundary layer and the intensity evolution offers further evidence in support of our hypothesis. The downdrafts that flush the boundary layer with low theta_e air are tied to a quasi-stationary, azimuthal wave number 1 convective asymmetry outside of the eyewall. This convective asymmetry and the associated downdraft pattern extends outwards to approximately 150 km. Downdrafts occur on the vortex scale and form when precipitation falls out from sloping updrafts and evaporates in the unsaturated air below. It is argued that, to zero order, the formation of the convective asymmetry is forced by frictional convergence associated with the azimuthal wave number 1 vortex Rossby wave structure of the outer-vortex tilt. This work points to an important connection between the thermodynamic impact in the near-core boundary layer and the asymmetric balanced dynamics governing the TC vortex evolution.

Roemmich, D., L. Boehme, H. Claustre, H. Freeland, M. Fukasawa, G. Goni, W.J. Gould, N. Gruber, M. Hood, E. Kent, R. Lumpkin, S. Smith, and P. Testor. Integrating the ocean observing system: Mobile platforms. In OceanObs09: Sustained Ocean Observations and Information for Society (Volume 2), J. Hall, D.E. Harrison, and D. Stammer (eds.). European Space Agency Publication, WPP-306, 27 pp. (2010).

No abstract.

Rogers, R.F. Convective-scale structure and evolution during a high-resolution simulation of tropical cyclone rapid intensification. Journal of the Atmospheric Sciences, 67(1):44-70 (2010).

The role of convective-scale processes in a 1.67-km mesoscale model simulation of the rapid intensification (RI) of Hurricane Dennis (2005) is presented. The structure and evolution of inner-core precipitating areas during RI, the statistical properties of precipitation during times experiencing vigorous convection (termed convective bursts here) and how they differ from nonburst times, possible differences in convective bursts associated with RI and those not associated with RI, and the impacts of precipitation morphology on the vortex-scale structure and evolution during RI are all examined. The onset of RI is linked to an increase in the areal extent of convective precipitation in the inner core, while the inner-core stratiform precipitating area remains unchanged and the intensity increases only after RI has begun. RI is not tied to a dramatic increase in the number of convective bursts nor in the characteristics of the bursts, such as burst intensity. Rather, the immediate cause of RI is a significant increase in updraft mass flux, particularly in the lowest 1.5 km. This increase in updraft mass flux is accomplished primarily by updrafts on the order of 1-2 m s^-1, representing the bulk of the vertical motion distribution. However, a period of enhanced updraft mass flux in the midlevels by moderate to strong (>5 m s^-1) updrafts located inside the radius of maximum winds occurs ~6 h prior to RI, indicating a synergistic relationship between convective bursts and the background secondary circulation prior to RI. This result supports the assertion that both buoyantly driven updrafts and slantwise near-neutral ascent are important features in eyewall structure, evolution, and intensification, including RI.

Rutherford, B., G. Dangelmayr, J. Persing, M. Kirby, and M.T. Montgomery. Lagrangian mixing in an axisymmetric hurricane model. Atmospheric Chemistry and Physics, 10(14):6777-6791 (2010).

This paper discusses the extension of established Lagrangian mixing measures to make them applicable to data extracted from a 2-D axisymmetric hurricane simulation. Because of the non-steady and unbounded characteristics of the simulation, the previous measures are extended to a moving frame approach to create time-dependent mixing rates that are dependent upon the initial time of particle integration, and are computed for nonlocal regions. The global measures of mixing derived from finite-time Lyapunov exponents, relative dispersion, and a measured mixing rate are applied to distinct regions representing different characteristic feautures within the model. It is shown that these time-dependent mixing rates exhibit correlations with maximal tangential winds during a quasi-steady state, establishing a connection between mixing and hurricane intensity.

Rutherford, B., G. Dangelmayr, J. Persing, W.H. Schubert, and M.T. Montgomery. Advective mixing in a nondivergent barotropic hurricane model. Atmospheric Chemistry and Physics, 10(2):475-497 (2010).

This paper studies Lagrangian mixing in a two-dimensional barotropic model for hurricane-like vortices. Since such flows show high shearing in the radial direction, particle separation across shear-lines is diagnosed through a Lagrangian field, referred to as R-field, that measures trajectory separation orthogonal to the Lagrangian velocity. The shear-lines are identified with the level-contours of another Lagrangian field, referred to as S-field, that measures the average shear-strength along a trajectory. Other fields used for model diagnostics are the Lagrangian field of finite-time Lyapunov exponents (FTLE-field), the Eulerian Q-field, and the angular velocity field. Because of the high shearing, the FTLE-field is not a suitable indicator for advective mixing, and in particular does not exhibit ridges marking the location of finite-time stable and unstable manifolds. The FTLE-field is similar in structure to the radial derivative of the angular velocity. In contrast, persisting ridges and valleys can be clearly recognized in the R-field, and their propagation speed indicates that transport across shear-lines is caused by Rossby waves. A radial mixing rate derived from the R-field gives a time-dependent measure of flux across the shear-lines. On the other hand, a measured mixing rate across the shear-lines, which counts trajectory crossings, confirms the results from the R-field mixing rate, and shows high mixing in the eyewall region after the formation of a polygonal eyewall, which continues until the vortex breaks down. The location of the R-field ridges elucidates the role of radial mixing for the interaction and breakdown of the mesovortices shown by the model.

Sabine, C.L., R.A. Feely, R. Wanninkhof, T. Takahashi, S. Khatiwala, and G.-H. Park. The global ocean carbon cycle. In State of the Climate in 2009, D.S. Arndt, M.O. Baringer, and M.R. Johnson (eds.). Bulletin of the American Meteorological Society, 91(6):71-75 (2010).

No abstract.

Send, U., R. Davis, J. Fischer, S. Imawaki, W. Kessler, C. Meinen, B. Owens, D. Roemmich, T. Rossby, D. Rudnick, J. Toole, S. Wijffels, and L. Beal. A global boundary current circulation observating network. In OceanObs09: Sustained Ocean Observations and Information for Society (Volume 2), J. Hall, D.E. Harrison, and D. Stammer (eds.). European Space Agency Publication, WPP-306, 16 pp. (2010).

No abstract.

Sereenonchai, K., S. Teerasong, S. Chan-Eam, P. Saetear, N. Choengchan, K. Uraisin, N. Amornthammarong, S. Motomizu, and D. Nacapricha. A low-cost method for determination of calcium carbonate in cement by membraneless vaporization with capacitively coupled contactless conductivity detection. Talanta, 81(3):1040-144 (2010).

This work presents a flow analysis method for direct quantitation of calcium carbonate in cement without pretreatment of the sample. The method is based on online vaporization of CO₂ gas following acidification of the sample inside a small chamber that has a flow of acceptor solution passing around it. Solubilization of the CO₂ gas into the acceptor stream changes the conductivity of the acceptor solution, causing an increase of signal at the capacitively coupled contactless conductivity detection (C⁴D) placed at the outlet of the vaporization chamber. This chamber is an adaption from previous work reported on membraneless vaporization (MBL-VP). The method can be used in the quality control of production of mixed cement. These cement materials usually have calcium carbonate contents at high concentration range (e.g., 33-99% (w/w) CaCO₃). Analysis of samples by this method is direct and convenient, as it requires no sample pretreatment. The method is low-cost with satisfactory accuracy and acceptable precision.

Shen, B.-W., W.-K. Tao, W.K. Lau, and R. Atlas. Predicting tropical cyclogenesis with a global mesoscale model: Hierarchical multiscale interactions during the formation of Tropical Cyclone Nargis (2008). Journal of Geophysical Research, 115:D14102, doi:10.1029/2009JD013140, 15 pp. (2010).

Very severe cyclonic storm Nargis devastated Burma (Myanmar) in May 2008, caused tremendous damage and numerous fatalities, and became one of the 10 deadliest tropical cyclones (TCs) of all time. To increase the warning time in order to save lives and reduce economic damage, it is important to extend the lead time in the prediction of TCs like Nargis. As recent advances in high-resolution global models and supercomputing technology have shown the potential for improving TC track and intensity forecasts, the ability of a global mesoscale model to predict TC genesis in the Indian Ocean is examined in this study with the aim of improving simulations of TC climate. High-resolution global simulations with real data show that the initial formation and intensity variations of TC Nargis can be realistically predicted up to 5 days in advance. Preliminary analysis suggests that improved representations of the following environmental conditions and their hierarchical multiscale interactions were the key to achieving this lead time: (1) a westerly wind burst and equatorial trough; (2) an enhanced monsoon circulation with a zero wind shear line; (3) good upper-level outflow with anti-cyclonic wind shear between 200 and 850 hPa; and (4) low-level moisture convergence.

Shibata, T., H.M. Solo-Gabriele, C.D. Sinigalliano, M.L. Gidley, L.R.W. Plano, J.M. Fleisher, J.D. Wang, S.M. Elmir, G. He, M.E. Wright, A.M. Abdelzaher, C. Ortega, D. Wanless, A.C. Garza, J. Kish, T. Scott, J. Hollenbeck, L.C. Backer, and L.E. Fleming. Evaluation of conventional and alternative monitoring methods for a recreational marine beach with nonpoint source of fecal contamination. Environmental Science and Technology, 44(21):8175-8181 (2010).

The objectives of this work were to compare enterococci (ENT) measurements based on the membrane filter, ENT(MF) with alternatives that can provide faster results including alternative enterococci methods (e.g., chromogenic substrate (CS), and quantitative polymerase chain reaction (qPCR)), and results from regression models based upon environmental parameters that can be measured in real-time. ENT(MF) were also compared to source tracking markers (Staphylococcus aureus, Bacteroidales human and dog markers, and Catellicoccus gull marker) in an effort to interpret the variability of the signal. Results showed that concentrations of enterococci based upon MF (<2 to 3320 CFU/100 mL) were significantly different from the CS and qPCR methods (p < 0.01). The correlations between MF and CS (r = 0.58, p < 0.01) were stronger than between MF and qPCR (r � 0.36, p < 0.01). Enterococci levels by MF, CS, and qPCR methods were positively correlated with turbidity and tidal height. Enterococci by MF and CS were also inversely correlated with solar radiation but enterococci by qPCR was not. The regression model based on environmental variables provided fair qualitative predictions of enterococci by MF in real-time, for daily geometric mean levels, but not for individual samples. Overall, ENT(MF) was not significantly correlated with source tracking markers with the exception of samples collected during one storm event. The inability of the regression model to predict ENT(MF) levels for individual samples is likely due to the different sources of ENT impacting the beach at any given time, making it particularly difficult to predict short-term variability of ENT(MF) for environmental parameters.

Sinigalliano, C.D., J.M. Fleisher, M.L. Gidley, H.M. Solo-Gabriele, T. Shibata, L.R.W. Plano, S.M. Elmir, D. Wanless, J. Bartkowiak, R. Boiteau, K. Withum, A.M. Abdelzaher, G. He, C. Ortega, X. Zhu, M.E. Wright, J. Kish, J. Hollenbeck, T. Scott, L.C. Backer, and L.E. Fleming. Traditional and molecular analyses for fecal indicator bacteria in non-point source subtropical recreational marine waters. Water Research, 44(13):3763-3772 (2010).

The use of enterococci as the primary fecal indicator bacteria (FIB) for the determination of recreational water safety has been questioned, particularly in sub/tropical marine waters without known point sources of sewage. Alternative FIB (such as the Bacteroidales group) and alternative measurement methods (such as rapid molecular testing) have been proposed to supplement or replace current marine water quality testing methods which require culturing enterococci. Moreover, environmental parameters have also been proposed to supplement current monitoring programs. The objective of this study was to evaluate the health risks to humans from exposure to subtropical recreational marine waters with no known point source. The study reported symptoms between one set of human subjects randomly assigned to marine water exposure with intensive environmental monitoring compared with other subjects who did not have exposure. In addition, illness outcomes among the exposed bathers were compared to levels of traditional and alternative FIB (as measured by culture-based and molecular-based methods) and compared to easily measured environmental parameters. Results demonstrated an increase in self-reported gastrointestinal, respiratory and skin illnesses among bathers versus non-bathers. Among the bathers, a dose-response relationship by logistic regression modeling was observed for skin illness, where illness was positively related to enterococci enumeration by membrane filtration (odds ratio = 1.46 [95% confidence interval = 0.97-2.21] per increasing log10 unit of enterococci exposure) and positively related to 24 hour antecedent rain fall (1.04 [1.01-1.07] per increasing millimeters of rain). Acute febrile respiratory illness was inversely related to water temperature (0.74 [0.56-0.98] per increasing degree of water temperature). There were no significant dose response relationships between report of human illness and any of the other FIB or environmental measures. Therefore, for non-point source subtropical recreational marine waters, this study suggests that humans may be at increased risk of reported illness, and that the currently recommended and investigational FIB may not track gastrointestinal illness under these conditions; the relationship between other human illness and environmental measures is less clear.

Smith, R.H. Atlantic-Caribbean exchange through Windward Passage. M.S. thesis. University of Miami, Rosenstiel School of Marine and Atmospheric Science, 130 pp. (2010).

Windward Passage, which separates the islands of Cuba and Hispaniola, has been recognized as an important inflow channel to the Caribbean Sea for nearly a century. Despite this fact, few direct measurements of the volume transport through the passage exist. In an effort to gain a more comprehensive understanding of the variability, structure, and mean transport associated with flow through Windward Passage, the University of Miamis Rosenstiel School of Marine and Atmospheric Science (RSMAS) and the National Oceanic and Atmospheric Administration (NOAA)s Atlantic Oceanographic and Meteorological Laboratory (AOML) conducted a targeted research study of the passage and surrounding region from October 2003 through February 2005. The project deployed a moored current meter array across the passage and conducted four regional hydrographic surveys. Velocity sections collected across Windward Passage during the four cruises from lowered and hull-mounted acoustic Doppler current profilers show a highly variable field dominated by small-scale eddy features and other areas of locally-intensified flow. However, when integrated horizontally across the passage, the resulting transport-per unit-depth profiles reveal a remarkably robust vertical shear structure. A net inflow of surface and thermocline waters was observed over the four cruises. Beneath these layers, a persistent outflow of intermediate water was found, intensified along the east side of the passage. Deep inflow, just above the sill depth maximum (1680 m), was observed on cruise #1 and, based on data from the moored current meter record, was determined to be a regular flow feature. Together, project velocity sections and water mass analyses of Windward and surrounding passages suggest that Surface Water (SFC), Subtropical Underwater (SUW), and Central Water (CW) primarily arrive at Windward Passage from the east via the Hispaniola Basin. A majority of SFC and SUW enters the Cayman Basin through Windward Passage, while the arriving CW bifurcates, with slightly more than half bypassing the passage and continuing westward north of Cuba. An intermediate water outflow pathway from the Cayman to the Hispaniola Basin via Windward Passage was also observed. Much of this outflow possessed a salinity signature characteristic of upstream inflow regions immediately to the east and south of the Lesser Antilles. Total Windward Passage transport, calculated from the four ship surveys, was found to be an inflow of 3.0 ± 2.8 Sverdrups (1 Sv equivalent to 10⁶ m³ s^-1). Data from the 16-month moored current meter array yielded a larger mean inflow of 5.0 ± 1.6 Sv. These numbers are lower than previous estimates based on regional passage transport differences, and suggest that more transport may be entering the Florida Current system through passages in the Bahamas (the Northwest Providence and Old Bahama Channels) than previously thought, with proportionately less flow entering the system through the Caribbean Sea.

Smith, R.K., and M.T Montgomery. Hurricane boundary-layer theory. Quarterly Journal of the Royal Meteorological Society, 136(652):1665-1670 (doi:10.1002/qj.679) (2010).

In the light of the plethora of definitions for the hurricane boundary layer, we advocate a dynamical definition based on the distribution of a gradient flow. We seek also to clarify the fundamental role of the boundary layer in the hurricane intensification process. In particular, we contrast the differences between unsteady boundary layers that are able to facilitate the spin-up of the vortex above and steady boundary layers that cannot. If slaved to the time-dependent vortex aloft, the latter can spin up the interior vortex only indirectly by changing its thermodynamic properties through vertical advection of these from below and adjustment to thermal wind balance. These differences are highlighted by an analytical demonstration that the application of a zero-vertical-gradient condition on velocity above a steady boundary layer does not provide a direct means of allowing the boundary layer to determine the flow in the interior vortex. This result assumes that frictional forces are negligible at this boundary. Finally, echoing a few previous insights, we question the applicability of conventional boundary-layer theory at radii of strong ascent into the eyewall, where the flow is akin to that of separation in aerodynamic boundary layers.

Smith, S.R., M.A. Bourassa, E.F. Bradley, C. Cosca, C.W. Fairall, G.J. Goni, J.T. Gunn, M. Hood, D.L. Jackson, E.C. Kent, G. Lagerloef, P. McGillivary, L. Petit de al Villeon, R.T. Pinker, E. Schulz, J. Sprintall, D. Stammer, A. Weill, G.A. Wick, and M.J. Yelland. Automated underway oceanic and atmospheric measurements from ships. In OceanObs09: Sustained Ocean Observations and Information for Society (Volume 2), J. Hall, D.E. Harrison, and D. Stammer (eds.), Venice, Italy, September 21-25, 2009. European Space Agency Publication, WPP-306,14 pp. (2010).

Merchant, cruise, and research vessels make unique contributions to marine data collection using automated oceanic and atmospheric monitoring systems. The programs making these observations are reviewed along with the wide range of applications to atmospheric and oceanic research and operations. A vision for the next decade outlines where incremental improvements to instruments, platforms, and data stewardship can benefit the community. A series of recommendations are made to meet the challenges of future-ocean observing.

Sun, C., A. Thresher, R. Keeley, N. Hall, M. Hamilton, P. Chinn, A. Tran, G. Goni, L. Petit de la Villeon, T. Carval, L. Cowen, G. Manzella, V. Gopalahrishna, R. Guerrero, F. Reseghetti, Y. Kanno, B. Klein, L. Rickards, A. Baldoni, S. Lin, F. Ji, and Y. Nagaya. The data management system for the Global Temperature and Salinity Profile Programme. In OceanObs09: Sustained Ocean Observations and Information for Society (Volume 2), J. Hall, D.E. Harrison, and D. Stammer (eds.). European Space Agency Publication, WPP-306, 8 pp. (2010).

No abstract.

Swart, P.K., L. Greer, B.E. Rosenheim, C.S. Moses, A.J. Waite, A. Winter, R.E. Dodge, and K. Helmle. The ¹³C Suess effect in scleractinian corals mirror changes in the anthropogenic CO₂ inventory of the surface oceans. Geophysical Research Letters, 37(5):L05604, doi:10.1029/2009GL041397 (2010).

New delta¹³C data are presented from 10 coral skeletons collected from Florida and elsewhere in the Caribbean (Dominica, Dominican Republic, Puerto Rico, and Belize). These corals range from 96 to 200 years in age and were collected between 1976 and 2002. The change in the delta¹³C of the skeletons from these corals between 1900 and 1990 has been compared with 27 other published coral records from the Atlantic, Pacific, and Indian Oceans. The new data presented here make possible, for the first time, a global comparison of rates of change in the delta¹³C value of coral skeletons. Of these records, 64% show a statistically significant (p < 0.05) decrease in delta¹³C towards the modern day (23 out of 37). This decrease is attributable to the addition of anthropogenically-derived CO₂ (¹³C Suess effect) to the atmosphere. Between 1900 and 1990, the average rate of change of the delta¹³C in all the coral skeletons living under open oceanic conditions is approximately -0.01 parts per thousand yr^-1. In the Atlantic Ocean the magnitude of the decrease since 1960, -0.019 yr^-1 ±0.015 parts per thousand, is essentially the same as the decrease in the delta¹³C of atmospheric CO₂ and the delta¹³C of the oceanic dissolved inorganic carbon (-0.023 to -0.029 parts per thousand yr^-1), while in the Pacific and Indian Oceans the rate is more variable and significantly reduced (-0.007 parts per thousand yr^-1 ±0.013). These data strongly support the notion that (i) the delta¹³C of the atmosphere controls ambient delta¹³C of the dissolved inorganic carbon which in turn is reflected in the coral skeletons, (ii) the rate of decline in the coral skeletons is higher in oceans with a greater anthropogenic CO₂ inventory in the surface oceans, (iii) the rate of delta¹³C decline is accelerating. Superimposed on these secular variations are controls on the delta¹³C in the skeleton governed by growth rate, insolation, and local water masses.

Tanhua, T., R. Steinfeldt, R.M. Key, P. Brown, N. Gruber, R. Wanninkhof, F. Perez, A. Kortzinger, A. Velo, U. Schuster, S. van Heuven, J.L. Bullister, I. Stendardo, M. Hoppema, A. Olsen, A. Kozyr, D. Pierrot, C. Schirnick, and D.W.R. Wallace. Atlantic Ocean CARINA data: Overview and salinity adjustments. Earth System Science Data, 2(1):17-34 (2010).

Water column data of carbon and carbon-relevant hydrographic and hydrochemical parameters from 188 previously non-publicly available cruise data sets in the Arctic Mediterranean Seas, Atlantic and Southern Ocean have been retrieved and merged into a new database: CARINA (CARbon dioxide IN the Atlantic Ocean). The data have gone through rigorous quality control procedures to assure the highest possible quality and consistency. The data for the pertinent parameters in the CARINA database were objectively examined in order to quantify systematic differences in the reported values, i.e., secondary quality control. Systematic biases found in the data have been corrected in the three data products: merged data files with measured, calculated, and interpolated data for each of the three CARINA regions, i.e., the Arctic Mediterranean Seas, the Atlantic and the Southern Ocean. These products have been corrected to be internally consistent. Ninety-eight of the cruises in the CARINA database were conducted in the Atlantic Ocean, defined here as the region south of the Greenland-Iceland-Scotland Ridge and north of about 30°S. Here we present an overview of the Atlantic Ocean synthesis of the CARINA data and the adjustments that were applied to the data product. We also report the details of the secondary QC (Quality Control) for salinity for this data set. Procedures of quality control, including crossover analysis between stations and inversion analysis of all crossover data, are briefly described. Adjustments to salinity measurements were applied to the data from 10 cruises in the Atlantic Ocean region. Based on our analysis we estimate the internal consistency of the CARINA-ATL salinity data to be 4.1 ppm. With these adjustments the CARINA data products are consistent both internally as well as with GLODAP data, an oceanographic data set based on the World Hydrographic Program in the 1990s, and is now suitable for accurate assessments of, for example, oceanic carbon inventories and uptake rates and for model validation.

Teerasong, S., S. Chan-Eam, K. Sereenonchai, N. Amornthammarong, N. Ratanawimarnwong, and D. Nacapricha. A reagent-free SIA module for monitoring of sugar, color, and dissolved CO₂ content in soft drinks. Analytica Chimica Acta, 668(1):47-53 (2010).

This work presents a new sequential injection analysis (SIA) method and a module for simultaneous and real-time monitoring of three key parameters for the beverage industry, i.e., the sugar content (measured in Brix), color, and dissolved CO₂. Detection of the light reflection at the liquid interface (the Schlieren effect) of sucrose and water was utilized for sucrose content measurement. A near infrared LED (890 ± 40 nm) was chosen as the light source to ensure that all the ingredients and dyes in the soft drinks did not interfere by contributing light absorption. A linear calibration was obtained for sucrose over a wide concentration range (3.1-46.5 Brix). The same module can be used to monitor the color of the soft drink, as well as the dissolved CO₂ during production. For measuring the color, the sample is segmented between air plugs to avoid dispersion. An RGB-LED was chosen as the light source in order to make this module applicable to a wide range of colored samples. The module also has a section where dissolved CO₂ is measured via vaporization of the gas from the liquid phase. Dissolved CO₂, in a flowing acceptor stream of water resulting in the change of the acceptor conductivity, is detected using an in-house capacitively coupled contactless conductivity detector (C⁴D). The module includes a vaporization unit that is also used to degas the carbonated drink, prior to the measurements of sucrose and color within the same system. The method requires no chemicals and is therefore completely friendly to the environment.

Teerasong, S., N. Amornthammarong, K. Grudpan, N. Teshima, T. Sakai, D. Nacapricha, and N. Ratanawimarnwong. A multiple processing hybrid flow system for analysis of formaldehyde contamination in food. Analytical Sciences, 26(5):629-633 (2010).

This work proposes a flow system suitable for the rapid screening of formaldehyde contaminated in food. The system is based on the concept of a flow analyzer with a Hantzsch reaction. An operating procedure was developed for multiple tasking and high sample throughput. This resulted in a significant sample throughput of 51 samples h^-1. Under the optimized conditions, linear calibration from 10 to 100 µM was obtained. The system gave a limit of detection and a limit of quantitation of 0.06 and 0.10 mg kg^-1, respectively. The system was successfully applied to rehydrated dry squids, vegetables, and mushrooms.

Testor, P., G. Meyers, C. Pattiaratchi, R. Bachmayer, D. Hayes, S. Pouliquen, L. Petit de la Villeon, T. Carval, A. Ganachaud, L. Gourdeau, L. Mortier, H. Claustre, V. Taillandier, P. Lherminier, T. Terre, M. Visbeck, J. Karstensen, G. Krahmann, A. Alvarez, M. Rixen, P.-M. Poulain, S. Osterhus, J. Tintore, S. Ruiz, B. Garau, D. Smeed, G. Griffiths, L. Merckelbach, T. Sherwin, C. Schmid, J.A. Barth. O. Schofield, S. Glenn, J. Kohut, M.J. Perry, C. Eriksen, U. Send, R. Davis, D. Rudnick, J. Sherman, C. Jones, D. Webb, C. Lee, and B. Owens. Gliders as a component of future observing systems. In OceanObs09: Sustained Ocean Observations and Information for Society (Volume 2), J. Hall, D.E. Harrison, and D. Stammer (eds.). European Space Agency Publication, WPP-306, 22 pp. (2010).

The aim of this community white paper is to make recommendations for a glider component of a global ocean observing system. We first recommend the adoption of an ARGO-like data system for gliders. Then, we argue that combining glider deployments with the other components (ships, moorings, floats and satellites) will considerably enhance our capacity for observing the ocean by filling gaps left by the other observing systems. Gliders could be deployed to sample most of the western and eastern boundary circulations and the regional seas (around 20 basins in the world) which are not well covered by the present global ocean observing system and in the vicinity of fixed point time series stations. These plans already involve people scattered around the world in Australia, Canada, Cyprus, France, Germany, Italy, Norway, Spain, UK,and the USA, and will certainly expand to many other countries. A rough estimate of resources required is about 13M$/Euro for ~20+ gliders permanently at sea during five years in the world ocean, based on present scientific infrastructures.

Tweddle, J.F., P.G. Strutton, D.G. Foley, L. O'Higgins, A.M. Wood, B. Scott, R.C. Everroad, W.T. Peterson, D. Cannon, M. Hunter, and Z. Forster. Relationships among upwelling, phytoplankton blooms, and phycotoxins in coastal Oregon shellfish. Marine Ecology Progress Series, 405:131-145 (2010).

Climatologies derived from satellite data (1998 to 2007) were used to elucidate seasonal and latitudinal patterns in winds, sea surface temperature (SST), and chlorophyll concentrations (chl) over the Oregon shelf. These were further used to reveal oceanographic conditions normally associated with harmful algal blooms (HABs) and toxic shellfish events along the Oregon coast. South of 43°N, around Cape Blanco, summer upwelling started earlier and finished later than north of 43°N. Spring blooms occur when light limitation is relieved, before the initiation of upwelling, and secondary, more intense blooms occur approximately 2 wk after upwelling is established. North of 45°N, SST and chl are heavily influenced by the Columbia River plume, which delays upwelling-driven cooling of the surface coastal ocean in spring, and causes phytoplankton blooms (as indicated by increased chl) earlier than expected. The presence of saxitoxin in coastal shellfish, which causes paralytic shellfish poisoning, was generally associated with late summer upwelling. The presence of domoic acid in shellfish, which leads to amnesic shellfish poisoning, was greatest during the transition between upwelling and downwelling regimes. This work demonstrates that satellite data can indicate physical situations when HABs are more likely to occur, thus providing a management tool useful in predicting or monitoring HABs.

Vukicevic, T., O. Coddington, and P. Pilewskie. Characterizing the retrieval of cloud properties from optical remote sensing. Journal of Geophysical Research, 115:D20211, doi:10.1029/2009JD012830, 14 pp. (2010).

This paper presents a new approach to the formal characterization of the optical retrieval of cloud optical thickness and effective droplet radius based on a nonlinear methodology that is derived from a general stochastic inverse problem formulation similar to standard Bayesian estimation theory. The methodology includes efficient use of the precomputed radiative transfer model simulations which are already available in standard retrieval algorithms. Another important property of the methodology is that it does not require performing the retrieval with actual measurements in order to characterize the retrieval results. One utility of this analysis is the quantification of information content in the standard retrieval problem, and the increase of information through adding channels (radiances at different wavelengths) to the inversion. This was demonstrated for the five-wavelength retrieval using airborne hyperspectral shortwave irradiance measurements. The ability of the method to evaluate the impact of observation and radiative transfer model uncertainties on the retrieved cloud properties is also demonstrated. Further benefits from this study will be in its application to the cloud retrieval algorithms to be developed for future space- and airborne instruments. The present study puts forth the framework necessary to quantify that increase in information and to optimize new retrieval algorithms that efficiently accommodate the enhanced measurement space.

Wang, C., and S. Dong. Is the basin-wide warming in the North Atlantic Ocean related to atmospheric carbon dioxide and global warming? Geophysical Research Letters, 37(8):L08707, doi:10.1029/2010GL042743 (2010).

A basin-wide warming in the North Atlantic Ocean has occurred since the mid-1990s; however, the cause of this basin-wide warming is controversial. Some studies argued that the warming is due to global warming in association with the secular increase of the atmospheric greenhouse gas of carbon dioxide (CO₂), while others suggested that it is caused by the Atlantic multidecadal oscillation (AMO), an oscillatory mode occurring in North Atlantic sea surface temperature. Here we show that both global warming and AMO variability make a contribution to the recent basin-wide warming in the North Atlantic and their relative contribution is approximately equal. It is further shown that after removing a linear trend and the seasonal cycle, atmospheric CO₂ measured from 1958-2008 varies approximately with the AMO. On the assumption that a linear trend can be removed from the CO₂ time series, then there are suggestive similarities between CO₂ and AMO temperature anomalies. That is, atmospheric CO₂ increases (decreases) when the AMO is in the warm (cold) phase. This would suggest that the recent basin-wide warming of the North Atlantic might contribute to global ocean warming via its associated increase of atmospheric CO₂.

Wang, C., and S.-K. Lee. Is hurricane activity in one basin tied to another? Eos, Transactions, American Geophysical Union, 91(10):93-94, doi:10.1029/2009ES002729 (2010).

No abstract.

Wang, C., S. Dong, and E. Munoz. Seawater density variations in the North Atlantic and the Atlantic meridional overturning circulation. Climate Dynamics, 34(7-8):953-968 (2010).

Seawater property changes in the North Atlantic Ocean affect the Atlantic meridional overturning circulation (AMOC), which transports warm water northward from the upper ocean and contributes to the temperate climate of Europe, as well as influences climate globally. Previous observational studies have focused on salinity and freshwater variability in the sinking region of the North Atlantic, since it is believed that a freshening North Atlantic basin can slow down or halt the flow of the AMOC. Here we use available data to show the importance of how density patterns over the upper ocean of the North Atlantic affect the strength of the AMOC. For the long-term trend, the upper ocean of the subpolar North Atlantic is becoming cooler and fresher, whereas the subtropical North Atlantic is becoming warmer and saltier. On a multidecadal timescale, the upper ocean of the North Atlantic has generally been warmer and saltier since 1995. The heat and salt content in the subpolar North Atlantic lags that in the subtropical North Atlantic by about 89 years, suggesting a lower latitude origin for the temperature and salinity anomalies. Because of the opposite effects of temperature and salinity on density for both long-term trend and multidecadal timescales, these variations do not result in a density reduction in the subpolar North Atlantic for slowing down the AMOC. Indeed, the variations in the meridional density gradient between the subpolar and subtropical North Atlantic Ocean suggest that the AMOC has become stronger over the past five decades. These observed results are supported by and consistent with some oceanic reanalysis products.

Wang, C., S.-K. Lee, and C.R. Mechoso. Interhemispheric influence of the Atlantic warm pool on the southeastern Pacific. Journal of Climate, 23(2):404-418 (2010).

The Atlantic warm pool (AWP) is a large body of warm water comprising the Gulf of Mexico, Caribbean Sea, and western tropical North Atlantic. The AWP can vary on seasonal, interannual, and multidecadal time scales. The maximum AWP size is in the boreal late summer and early fall, with the largest extent in the year being about three times the smallest one. The AWP alternates with the Amazon basin in South America as the seasonal heating source for circulations of the Hadley and Walker type in the Western Hemisphere. During the boreal summer/fall, a strong Hadley-type circulation is established, with ascending motion over the AWP and subsidence over the southeastern tropical Pacific. This is accompanied by equatorward flow in the lower troposphere over the southeastern tropical Pacific, as dynamically required by the Sverdrup vorticity balance. It is shown by analyses of observational data and NCAR community atmospheric model simulations that an anomalously large (small) AWP during the boreal summer/fall results in a strengthening (weakening) of the Hadley-type circulation with enhanced descent (ascent) over the southeastern tropical Pacific. It is further demonstratedby using a simple two-level model linearized about a specified background mean statethat the interhemispheric connection between the AWP and the southeastern tropical Pacific depends on the configuration of the background mean zonal winds in the Southern Hemisphere.

Wang, C., H. Liu, and S.-K. Lee. The record-breaking cold temperatures during in the winter of 2009/2010 in the northern hemisphere. Atmospheric Science Letters, 11(3):161-168 (2010).

In this study, we show that the record-breaking cold temperatures from North America to Europe and Asia during the period of 28 December 2009 to 13 January 2010 were associated with extremely negative values of the North Atlantic Oscillation (NAO) index, which produced northerly surface wind anomalies and caused the southward advection of cold Arctic air. Corresponding to longer-term variations of Pacific and Atlantic sea surface temperatures (SSTs), the downward trend of the NAO has occurred since the early 1990s. It is speculated that if the downward trend of the NAO continues, more frequent cold outbreaks and heavy snow are likely in the coming years.

Wang, G., C. Wang, and R.X. Huang. Interdecadal variability of the Eastward Current in the South China Sea associated with the summer Asian Monsoon. Journal of Climate, 23(22):6115-6123 (doi:10.1175/2010JCLI3607.1) (2010).

Based on the Simple Ocean Data Assimilation (SODA) dataset and three types of Sverdrup streamfunction, an interdecadal variability of the eastward current in the middle South China Sea (SCS) during summer is identified. Both the pattern and strength of the summer Asian monsoon wind stress curl over the SCS contribute to the interdecadal variability of this current. From 1960 to 1979, the monsoon intensified and the zero wind stress curl line shifted southward. Both the core of positive wind stress curl in the northern SCS and the negative curl in the southern SCS moved southward and thus induced a southward shift of both the southern anticyclonic and northern cyclonic gyres, resulting in a southward displacement of the eastward current associated with these two gyres. In the meantime, the southern (northern) SCS anticyclonic (cyclonic) ocean gyre weakened (strengthened) and therefore also induced the southward shift of the eastward current near the intergyre boundary. In contrast, the eastward current shifted northward from 1980 to 1998 because the monsoon relaxed and the zero wind stress curl line shifted northward. After 1998, the eastward jet moved southward again as the zero wind stress curl line shifted southward and the SCS monsoon strengthened. The eastward current identified from the baroclinic streamfunction moved about 1.7° more southward than that from the barotropic streamfunction, indicating that the meridional position of the eastward current is depth dependent.

Wang, Z., M.T. Montgomery, and T.J. Dunkerton. Genesis of pre-Hurricane Felix (2007), Part 1: The role of the easterly wave critical layer. Journal of the Atmospheric Sciences, 67(6):1711-1729 (2010).

The formation of pre-Hurricane Felix (2007) in a tropical easterly wave is examined in a two-part study using the Weather Research and Forecasting (WRF) model with a high-resolution nested grid configuration that permits the representation of cloud system processes. The simulation commences during the wave stage of the precursor African easterly-wave disturbance. Here the simulated and observed developments are compared, while in Part II of the study various large-scale analyses, physical parameterizations, and initialization times are explored to document model sensitivities. In this first part, the authors focus on the wave/vortex morphology, its interaction with the adjacent intertropical convergence zone complex, and the vorticity balance in the neighborhood of the developing storm. Analysis of the model simulation points to a bottom-up development process within the wave critical layer and supports the three new hypotheses of tropical cyclone formation proposed recently by Dunkerton, Montgomery, and Wang. It is shown also that low-level convergence associated with the ITCZ helps to enhance the wave signal and extend the wave pouch from the jet level to the top of the atmospheric boundary layer. The region of a quasi-closed Lagrangian circulation within the wave pouch provides a focal point for diabatic merger of convective vortices and their vortical remnants. The wave pouch serves also to protect the moist air inside from dry air intrusion, providing a favorable environment for sustained deep convection. Consistent with the authors earlier findings, the tropical storm forms near the center of the wave pouch via system-scale convergence in the lower troposphere and vorticity aggregation. Components of the vorticity balance are shown to be scale dependent, with the immediate effects of cloud processes confined more closely to the storm center than the overturning Eliassen circulation induced by diabatic heating, the influence of which extends to larger radii.

Wang, Z., M.T. Montgomery, and T.J. Dunkerton. Genesis of pre-Hurricane Felix (2007), Part 2: Warm core formation, precipitation evolution, and predictability. Journal of the Atmospheric Sciences, 67(6):1730-1744 (2010).

This is the second of a two-part study examining the simulated formation of Atlantic Hurricane Felix (2007) in a cloud-representing framework. Here several open issues are addressed concerning the formation of the storms warm core, the evolution and respective contribution of stratiform versus convective precipitation within the parent waves pouch, and the sensitivity of the development pathway reported in Part I to different model physics options and initial conditions. All but one of the experiments include ice microphysics as represented by one of several parameterizations, and the partition of convective versus stratiform precipitation is accomplished using a standard numerical technique based on the high-resolution control experiment. The transition to a warm-core tropical cyclone from an initially cold-core, lower tropospheric wave disturbance is analyzed first. As part of this transformation process, it is shown that deep moist convection is sustained near the pouch center. Both convective and stratiform precipitation rates increase with time. While stratiform precipitation occupies a larger area even at the tropical storm stage, deep moist convection makes a comparable contribution to the total rain rate at the pregenesis stage, and a larger contribution than stratiform processes at the storm stage. The convergence profile averaged near the pouch center is found to become dominantly convective with increasing deep moist convective activity there. Low-level convergence forced by interior diabatic heating plays a key role in forming and intensifying the near-surface closed circulation, while the midlevel convergence associated with stratiform precipitation helps to increase the midlevel circulation and thereby contributes to the formation and upward extension of a tropospheric-deep cyclonic vortex. Sensitivity tests with different model physics options and initial conditions demonstrate a similar pregenesis evolution. These tests suggest that the genesis location of a tropical storm is largely controlled by the parent waves critical layer, whereas the genesis time and intensity of the protovortex depend on the details of the mesoscale organization, which is less predictable. Some implications of the findings are discussed.

Wanninkhof, R., S.C. Doney, J.L. Bullister, N.M. Levine, M. Warner, and N. Gruber. Detecting anthropogenic CO₂ changes in the interior Atlantic Ocean between 1989 and 2005. Journal of Geophysical Research, 115:C11028, 25 pp. (doi:10.1029/2010JC006251) (2010).

Repeat observations along the meridional Atlantic section A16 from Iceland to 56°S show substantial changes in the total dissolved inorganic carbon (DIC) concentrations in the ocean between occupations from 1989 through 2005. The changes correspond to the expected increase in DIC driven by the uptake of anthropogenic CO₂ from the atmosphere, but the DELTA-DIC is more varied and larger, in some locations, than can be explained solely by this process. Concomitant large changes in oxygen (O₂) suggest that processes acting on the natural carbon cycle also contribute to DELTA-DIC. Precise partial pressure of CO₂ measurements suggest small but systematic increases in the bottom waters. To isolate the anthropogenic CO₂ component (DELTA-C_anthro) from DELTA-DIC, an extended multilinear regression approach is applied along isopycnal surfaces. This yields an average depth-integrated DELTA-C_anthro of 0.53 ± 0.05 mol m^-2 yr^-1 with maximum values in the temperate zones of both hemispheres and a minimum in the tropical Atlantic. A higher decadal increase in the anthropogenic CO₂ inventory is found for the South Atlantic compared to the North Atlantic. This anthropogenic CO₂ accumulation pattern is opposite to that seen for the entire Anthropocene up to the 1990s. This change could perhaps be a consequence of the reduced downward transport of anthropogenic CO₂ in the North Atlantic due to recent climate variability. Extrapolating the results for this section to the entire Atlantic basin (63°N to 56°S) yields an uptake of 5 ± 1 Pg C decade^-1, which corresponds to about 25% of the annual global ocean uptake of anthropogenic CO₂ during this period.

Zhang, J.A. Estimation of dissipative heating using low-level in-situ aircraft observations in the hurricane boundary layer. Journal of the Atmospheric Sciences, 67(6):1853-1862 (2010).

Data collected in the low-level atmospheric boundary layer in five hurricanes by NOAA research aircraft are analyzed to measure turbulence with scales small enough to retrieve the rate of dissipation. A total of 49 flux runs suitable for analysis are identified in the atmospheric boundary layer within 200 m above the sea surface. Momentum fluxes are directly determined using the eddy correlation method, and drag coefficients are also calculated. The dissipative heating is estimated using two different methods: (1) integrating the rate of dissipation in the surface layer; and (2) multiplying the drag coefficient by the cube of surface wind speed. While the latter method has been widely used in theoretical models as well as several numerical models simulating hurricanes, these analyses show that using this method would significantly overestimate the magnitude of dissipative heating. Although the dataset used in this study is limited by the surface wind speed range < 30 m s^-1, this work highlights that it is crucial to understand the physical processes related to dissipative heating in the hurricane boundary layer for implementing it into hurricane models.

Zhang, J.A. Spectral characteristics of turbulence in the hurricane boundary layer over ocean between the outer rainbands. Quarterly Journal of the Royal Meteorological Society, 136(649):918-926 (2010).

Spectra and cospectra of wind velocity, potential temperature, and humidity have been analyzed using data collected in the atmospheric boundary layer in Hurricanes Fabian (2003) and Isabel (2003) during the Coupled Boundary Layer Air- Sea Transfer (CBLAST) hurricane experiment. The spectra and cospectra are normalized following the surface layer scaling methods according to similarity theory. It is found that the CBLAST data gathered in the mixed layer between the outer rain bands below 400 m can be grouped into well-defined curves for spectra of wind velocity, potential temperature and humidity, and for cospectra of momentum and humidity flux. However, the cospectra of sensible heat flux do not exhibit well-defined universal shape. The CBLAST universal shape spectra and cospectra generally resemble the shapes of those from previous studies, but shift to higher frequencies that correspond to smaller wavelengths of turbulent eddies that contain most of the energy. This work highlights the structural difference between the hurricane boundary layer and the standard atmospheric boundary layer over land and ocean.

Zhang, J.-Z., L. Guo, and C.J. Fischer. Abundance and chemical speciation of phosphorus in sediments of the Mackenzie River Delta, the Chukchi Sea, and the Bering Sea: Importance of detrital apatite. Aquatic Geochemistry, 16(3):353-371 (2010).

Utilizing a sequential extraction technique this study provides the first quantitative analysis on the abundance of sedimentary phosphorus and its partitioning between chemically distinguishable phases in sediments of the Bering Sea, the Chukchi Sea and the Mackenzie River Delta in the western Arctic Ocean. Total sedimentary phosphorus (TSP) was fractionated into five operationally defined phases: (1) adsorbed inorganic and exchangeable organic phosphorus; (2) Fe-bound inorganic phosphorus; (3) authigenic carbonate fluorapatite, biogenic apatite, and calcium carbonate-bound inorganic and organic phosphorus; (4) detrital apatite; and (5) refractory organic phosphorus. TSP concentrations in surface sediments increased from the Chukchi Sea (18 µmol g^-1 of dried sediments) to the Bering Sea (22 µmol g^-1) and to the Mackenzie River Delta (29 µmol g^-1). Among the five pools, detrital apatite phosphorus of igneous or metamorphic origin represents the largest fraction (~43%) of TSP. The second largest pool is the authigenic carbonate fluorapatite, biogenic apatite as well as CaCO₃ associated phosphorus (~24% of TSP), followed by the Fe-bound inorganic phosphorus, representing ~20% of TSP. The refractory organic P accounts for ~10% of TSP and the readily exchangeable adsorbed P accounts for only 3.5% of TSP. Inorganic phosphorus dominates all of phosphorus pools, accounting for an average of 87% of the TSP. Relatively high sedimentary organic carbon and total nitrogen contents and low delta¹³C values in the Mackenzie River Delta together with the dominance of detrital apatite in the TSP demonstrate the importance of riverine inputs in governing the abundance and speciation of sedimentary phosphorus in the Arctic coastal sediments. **2009**

Aberson, S.D. Regimes or cycles in tropical cyclone activity in the North Atlantic. Bulletin of the American Meteorological Society, 90(1):39-43 (2009).

The important role of the correct use of statistics in the atmospheric sciences literature is once again emphasized. Despite previous work on this topic, statistical techniques, even very simple ones, continue to be misused or altogether neglected, with the inevitable result of misleading or erroneous conclusions. An example concerning the impact of global climate change and hurricane activity is presented.

Aksoy, A., D.C. Dowell, and C. Snyder. A multicase comparative assessment of the ensemble Kalman filter for assimilation of radar observations, Part I: Storm-scale analyses. Monthly Weather Review, 137(6):1805-1824 (2009).

The effectiveness of the ensemble Kalman filter (EnKF) for assimilating radar observations at convective scales is investigated for cases whose behaviors span supercellular, linear, and multicellular organization. The parallel EnKF algorithm of the Data Assimilation Research Testbed (DART) is used for data assimilation, while the Weather Research and Forecasting (WRF) Model is employed as a simplified cloud model at 2-km horizontal grid spacing. In each case, reflectivity and radial velocity measurements are utilized from a single Weather Surveillance Radar-1988 Doppler (WSR-88D) within the U.S. operational network. Observations are assimilated every 2 min for a duration of 60 min and correction of folded radial velocities occurs within the EnKF. Initial ensemble uncertainty includes random perturbations to the horizontal wind components of the initial environmental sounding. The EnKF performs effectively and with robust results across all the cases. Over the first 18-30 min of assimilation, the rms and domain-averaged prior fits to observations in each case improve significantly from their initial levels, reaching comparable values of 3-6 m s^-1 and 7-10 dBZ. Representation of mesoscale uncertainty, albeit in the simplest form of initial sounding perturbations, is a critical part of the assimilation system, as it increases ensemble spread and improves filter performance. In addition, assimilation of no precipitation observations (i.e., reflectivity observations with values small enough to indicate the absence of precipitation) serves to suppress spurious convection in ensemble members. At the same time, it is clear that the assimilation is far from optimal, as the ensemble spread is consistently smaller than what would be expected from the innovation statistics and the assumed observation-error variance.

Amornthammarong, N., and J.-Z. Zhang. Liquid-waveguide spectrophotometric measurement of low silicate in natural waters. Talanta, 79(3):621-626 (2009).

This paper describes a robust, sensitive method for measurement of low silicate in natural water. The method is based on the reaction of silicate with ammonium molybdate to form a yellow silicomolybdate complex, which is then reduced to silicomolybdenum blue by ascorbic acid. This method shows no refractive index effect and a small salinity effect that can be corrected for seawater samples. It was found that the use of poly-vinyl alcohol can prevent the precipitation formation in the ammonium molybdate solution and improve the stability of the silicomolybdenum blue complex. The sensitivity of this method is substantially enhanced by using a liquid-waveguide capillary cell. The detection limit is 0.1 �M and the working range is 0.1-10 �M for using a 2-m liquid-waveguide capillary cell (LWCC). The method can be used for both freshwater and seawater samples and has been used to study the distribution of silicate in surface seawater of Gulf Stream in the Florida Straits.

Amornthammarong, N., D. Nacapricha, K. Sereenonchai, P. Anujarawat, and P. Wilairat. Audible-wave telemetry with PC sound card for remote analysis applications. In Telemetry: Research, Technology, and Applications, D. Barculo and J. Daniels (eds.). Nova Science Publishers, New York, 205-214 (2009).

This chapter describes the development of a cost-effective telemetric system through a combination of a wireless microphone for signal transmission and a computer sound card for recording of signals in the audible range. Three common communication systems, which are normally used for voice transmission, were compared for data transmission. The final developed telemeter provides a high potential for remote monitoring up to a distance of 30 m with a sampling rate of 10 Hz and 100% accuracy with low noise. The working signal range was from 0 to o2 volts, with resolution of more than a 10 bit A/D. A satisfactorily good precision of 0.1% RSD was achieved. The system works well for wireless monitoring of output from a spectrophotometer and pH meter. This work also demonstrated successful applications of the telemetric system with various chemical analyses in our laboratory.

Ardizonne, J., R. Atlas, R.N. Hoffman, J.C. Jusem, S.M. Leidner, and D.F. Moroni. New multiplatform ocean surface wind product available. EOS, Transactions, American Geophysical Union, 90(27):231 (2009).

No abstract.

Atlas, R., R.N. Hoffmann, and J. Ardizonne. A cross-calibrated multiple platform ocean surface wind data set. In Ocean Remote Sensing: Methods and Applications, J. Frouin (ed.). Proceedings, SPIE, 7459, doi:10.1117/12.824465, 9 pp. (2009).

A cross-calibrated, multi-satellite ocean surface wind data is described. It covers the global ocean for the twenty-one year period from 1987 to 2008 with 6-hour and 25-km resolution. This data set is produced using all ocean surface wind speed observations from SSM/I, AMSR-E, and TMI, and all ocean surface wind vector observations from QuikSCAT and SeaWinds. An enhanced variational analysis method (VAM) performs quality control and combines these data with available conventional ship and buoy data and ECMWF analyses. The VAM analyses fit the data used and withheld data very closely and contain small-scale structures not present in operational analyses. These data should be extremely useful to atmospheric and oceanic research, and to air-sea interaction studies.

Atlas, R., R.N. Hoffman, J. Ardizzone, M. Leidner, and J.C. Jusem. Development of a new cross-calibrated, multi-platform (CCMP) ocean surface wind product. Preprint Volume, 13th Conference on Integrated Observing and Assimilation Systems for the Atmosphere, Oceans, and Land Surface, Phoenix, AZ, January 11-15, 2009. American Meteorological Society, Boston, 5 pp. (2009).

No abstract.

Baringer, M.O., C.S. Meinen, G.C. Johnson, T.O. Kanzow, S.A. Cunningham, W.E. Johns, L.M. Beal, J.J.-M. Hirschi, D. Rayner, H.R. Longworth, H.L. Bryden, and J. Marotzke. The meridional overturning circulation. In State of the Climate in 2008, T.C. Peterson and M.O. Baringer (eds.). Bulletin of the American Meteorological Society, 90(8):S59-S62 (2009).

No abstract.

Bell, G.D., E. Blake, S.B. Goldenberg, T. Kimberlain, C.W. Landsea, R. Pasch, and J. Schemm. Tropical cyclones: Atlantic basin. In State of the Climate in 2008, T.C. Peterson and M.O. Baringer (eds.). Bulletin of the American Meteorological Society, 90(8):S79-S83 (2009).

No abstract.

Biastoch, A., L.M. Beal, J.R.E. Lutjeharms, and T.G.D. Casal. Variability and coherence of the Agulhas Undercurrent in a high-resolution ocean general circulation model. Journal of Physical Oceanography, 39(10):2417-2435 (2009).

The Agulhas Current system has been analyzed in a nested high-resolution ocean model and compared to observations. The model shows good performance in the western boundary current structure and the transports off the South African coast. This includes the simulation of the northward-flowing Agulhas Undercurrent. It is demonstrated that fluctuations of the Agulhas Current and Undercurrent around 50-70 days are due to Natal pulses and Mozambique eddies propagating downstream. A sensitivity experiment that excludes those upstream perturbations significantly reduces the variability as well as the mean transport of the undercurrent. Although the model simulates undercurrents in the Mozambique Channel and east of Madagascar, there is no direct connection between those and the Agulhas Undercurrent. Virtual float releases demonstrate that topography is effectively blocking the flow toward the north.

Boehm, A.B., J. Griffith, C. McGee, T.A. Edge, H.M. Solo-Gabriele, R. Whitman, Y. Cao, M. Getrich, J.A. Jay, D. Ferguson, K.D. Goodwin, C.M. Lee, M. Madison, and S.B. Weisberg. Fecal indicator bacteria enumeration in beach sand: A comparison study of extraction methods in medium to coarse sands. Journal of Applied Microbiology, 107(5):1740-1750 (2009).

The absence of standardized methods for quantifying fecal indicator bacteria (FIB) in sand hinders comparison of results across studies. The purpose of the study was to compare methods for extraction of fecal bacteria from sands and recommend a standardized extraction technique. Twenty-two methods of extracting enterococci and Escherichia coli from sand were evaluated, including multiple permutations of hand shaking, mechanical shaking, blending, sonication, number of rinses, settling time, eluant-to-sand ratio, eluant composition, prefiltration and type of decantation. Tests were performed on sands from California, Florida, and Lake Michigan. Most extraction parameters did not significantly affect bacterial enumeration. ANOVA revealed significant effects of eluant composition and blending; with both sodium metaphosphate buffer and blending producing reduced counts. The simplest extraction method that produced the highest FIB recoveries consisted of 2 min of hand shaking in phosphate-buffered saline or deionized water, a 30-s settling time, one-rinse step and a 10:1 eluant volume to sand weight ratio. This result was consistent across the sand compositions tested in this study but could vary for other sand types.

Boyer, J.N., C.R. Kelble, P.B. Ortner, and D.T. Rudnick. Phytoplankton bloom status: An indicator of water quality condition in the southern estuaries of Florida, USA. Ecological Indicators, 9(6) (Suppl):S56-S67 (2009).

Altered freshwater inflows have affected circulation, salinity, and water quality patterns of Florida Bay, in turn altering the structure and function of this estuary. Changes in water quality and salinity and associated loss of dense turtle grass and other submerged aquatic vegetation (SAV) in Florida Bay have created a condition in the bay where sediments and nutrients have been regularly disturbed, frequently causing large and dense phytoplankton blooms. These algal and cyanobacterial blooms in turn often cause further loss of more recently established SAV, exacerbating the conditions causing the blooms. Chlorophyll a (CHLA) was selected as an indicator of water quality because it is an indicator of phytoplankton biomass, with concentrations reflecting the integrated effect of many of the water quality factors that may be altered by restoration activities. Overall, we assessed the CHLA indicator as being (1) relevant and reflecting the state of the Florida Bay ecosystem, (2) sensitive to ecosystem drivers (stressors, especially nutrient loading), (3) feasible to monitor, and (4) scientifically defensible. Distinct zones within the bay were defined according to statistical and consensual information. Threshold levels of CHLA for each zone were defined using historical data and scientific consensus. A presentation template of condition of the bay using these thresholds is shown as an example of an outreach product.

Bui, H.-H., R.K. Smith, M.T. Montgomery, and J. Peng. Balanced and unbalanced aspects of tropical cyclone intensification. Quarterly Journal of the Royal Meteorological Society, 135(644):1715-1731 (2009).

We investigate the extent to which the azimuthally-averaged fields from a three-dimensional, non-hydrostatic, tropical cyclone model can be captured by axisymmetric balance theory. The secondary (overturning) circulation and balanced tendency for the primary circulation are obtained by solving a general form of the Sawyer-Eliassen equation with the diabatic heating, eddy heat fluxes and tangential momentum sources (eddy momentum fluxes, boundary-layer friction and subgrid-scale diffusion) diagnosed from the model. The occurrence of regions of weak symmetric instability at low levels and in the upper-tropospheric outflow layer requires a regularization procedure so that the Sawyer-Eliassen equation remains elliptic. The balanced calculations presented capture a major fraction of the azimuthally-averaged secondary circulation of the three-dimensional simulation except in the boundary layer, where the balanced assumption breaks down and where there is an inward agradient force. In particular, the balance theory is shown to significantly underestimate the low-level radial inflow and therefore the maximum azimuthal-mean tangential wind tendency. In the balance theory, the diabatic forcing associated with the eyewall convection accounts for a large fraction of the secondary circulation. The findings herein underscore both the utility of axisymmetric balance theory and also its limitations in describing the axisymmetric intensification physics of a tropical cyclone vortex.

Burpee, R.W. The Sanders barotropic tropical cyclone track model (SANBAR). In Synoptic-Dynamic Meteorology and Weather Analysis and Forecasting: A Tribute to Fred Sanders, L.F. Bosart and H.B. Bluestein (eds.). Meteorological Monograph, Volume 33, No. 55, American Meteorological Society, 233-240 (2009).

Sanders designed a barotropic tropical cyclone (TC) track model for the North Atlantic TC basin that became known as SANBAR. It predicted the stream function of the deep layer mean winds (averaged from 1000-100 hPa) that represented the vertically averaged tropical circulations. Originally, the wind input for the operational objective analysis (OA) consisted of winds measured by radiosondes and 44 bogus winds subjectively estimated by analysts at the National Hurricane Center (NHC) that corresponded to the vertically averaged flow over sparsely observed tropical and subtropical oceanic regions. The model covered a fixed regional area and had a grid size of about 154 km. It estimated the initial storm motion solely on the basis of the prevailing flow from the OA, not taking into account the observed storm motion. During 1970, the SANBAR model became the first dynamical TC track model to be run operationally at NHC. The track forecasts of SANBAR were verified from the 1971 TC season when track model verifications began at NHC until its retirement after the 1989 season. The average annual SANBAR forecast track errors are verified relative to CLIPER, the standard no-skill track forecast. Comparison with CLIPER determines the skill of track forecast methods. Verifications are presented for two different versions of the model system used operationally from 1973-84 and 1985-89. In homogeneous comparisons for the former period, SANBARs track forecasts were slightly better than CLIPER at 24-48 h forecast intervals; however, from 1985-89, the average SANBAR track forecast errors from 24-72 h were ~10% more skillful than homogeneous CLIPER track forecasts.

Carsey, T., K.D. Goodwin, J. Hendee, J.R. Proni, C. Sinigalliano, J. Stewart, J.-Z. Zhang, N. Amornthammarong, J. Craynock, S. Cummings, P. Dammann, C. Featherstone, J. Stamates, and K. Sullivan. A glimpse of the Florida Area Coastal Environment (FACE) program. Proceedings, 11th International Coral Reef Symposium, Ft. Lauderdale, FL, July 7-11, 2008. International Society for Reef Studies, 559-563 (2009). (peer reviewed)

The Florida Area Coastal Environment (FACE) research program gathers a variety of data related to water inputs into the coastal zone of southeast Florida. The water inputs studied include treated wastewater discharges, inlet flows, and upwelling events. Measurements include currents, nutrients, microbial contaminants, and stable isotopes. This report provides a glimpse of the data collected in this program. Data collected from the Boynton inlet point to the significance of this discharge as a source of nutrient and microbiological loads to coastal waters and demonstrate the importance of accounting for all major discharges in order to fully understand the impact of land use and water management decisions on coastal resources.

Casal, T.G.D., L.M. Beal, R. Lumpkin, and W.E. Johns. Structure and downstream evolution of the Agulhas Current system during a quasi-synoptic survey in February-March 2003. Journal of Geophysical Research, 114(C3):C03001, doi:10.1029/2008JC004954 (2009).

The Agulhas Undercurrent Experiment took place in February-March 2003 off the east coast of South Africa and consisted of four sections of hydrographic and velocity data across the Agulhas Current between 30 and 36°S and connecting offshore sections that formed three closed boxes. An inverse model was applied to the quasi-synoptic data, and results show that the net mass transport at the historical 32°S section had a considerably higher transport of 100 ± 9 Sv than earlier estimates. This high transport falls within the peak-to-peak variability obtained previously from a current meter time series. Several mesoscale cyclonic eddies extending down to intermediate depths were sampled during the survey; in particular, a strong, locally formed shear edge eddy was found inshore of the Agulhas Current at 36°S. Offshore eddies were found to drive considerable onshore-offshore fluxes, resulting in highly variable Agulhas transports from one section to another. After attempting to account for and remove the influence of these eddies on the Agulhas transport, the downstream growth of the Agulhas Current is found to be consistent with the Sverdrup transport variation, within errors. To account for the total magnitude of the Agulhas transport, fluxes from both the Indonesian Throughflow and Indian Ocean overturning must also be taken into account. There is no clear evidence from this study for a significant contribution of inertial recirculation to the Agulhas within this latitude range.

Chassignet, E.P., H.E. Hurlburt, E.J. Metzger, O.M. Smedstad, J.A. Cummings, G.R. Halliwell, R. Bleck, R. Baraille, A.J. Wallcraft, C. Lozano, H.L. Tolman, A. Srinivasan, S. Hankin, P. Cornillon, R. Weisberg, A. Barth, R. He, F. Werner, and J. Wilkin. U.S. GODAE: Global Ocean Prediction with the HYbrid Coordinate Ocean Model (HYCOM). Oceanography, 22(2):64-75 (2009).

During the past five to ten years, a broad partnership of institutions under NOPP sponsorship has collaborated in developing and demonstrating the performance and application of eddy-resolving, real-time global- and basin-scale ocean prediction systems using the Hybrid Coordinate Ocean Model (HYCOM). The partnership represents a broad spectrum of the oceanographic community, bringing together academia, federal agencies, and industry/commercial entities, and spanning modeling, data assimilation, data management and serving, observational capabilities, and application of HYCOM prediction system outputs. In addition to providing real-time, eddy-resolving global- and basin-scale ocean prediction systems for the U.S. Navy and NOAA, this project also offered an outstanding opportunity for NOAA-Navy collaboration and cooperation, ranging from research to the operational level. This paper provides an overview of the global HYCOM ocean prediction system and highlights some of its achievements. An important outcome of this effort is the capability of the global system to provide boundary conditions to even higher-resolution regional and coastal models.

Chierici, M., A. Olsen, T. Johannessen, J. Trinanes, and R. Wanninkhof. Algorithms to estimate the carbon dioxide uptake in the northern North Atlantic using shipboard observations, satellite, and ocean analysis data. Deep-Sea Research, Part II, 56(8-10):630-639 (2009).

Observations of the surface-water fugacity of carbon dioxide (fCO₂^sw) measured during 2005 in the subpolar North Atlantic Ocean (58-62°N, 10-40°W) were used together with in-situ ocean data and remotely sensed data to develop algorithms to estimate fCO₂^sw. Based on multiple regression, we found that sea-surface temperature (SST), mixed-layer depth (MLD), and chlorophyll a (chl a) contributed significantly to the fit. Two algorithms were developed for periods depending on the presence of chl a data. The correlation coefficient (r²) and the root-mean-square deviation (rms) for the best fit in the period when chl a was observed (20 March-15 October) were 0.720 and ±10.8 µatm, respectively. The best fit for the algorithm for the period when no chl a was present (16 October-19 March) resulted in a r² of 0.774 and a rms of ±5.6 µatm. Based on these algorithms, we estimated seasonal fields of fCO₂^sw and the air-sea CO₂ flux. The estimated net annual CO₂ sink was 0.0058 Gt C yr^-1 or 0.6 mol C m^-2 yr^-1.

Clark, C., D.E. Harrison, M. Johnson, G. Ball, H. Freeland, G.J. Goni, M. Hood, M. McPhaden, D. Meldrum, M. Merrifield, D. Roemmich, C. Sabine, U. Send, R. Weller, S. Wilson, J. Benveniste, H. Bonekamp, C. Donlon, M. Drinkwater, J.-L. Fellous, B.S. Gohil, G. Jacobs, P.-Y. Le Traon, E. Lindstrom, L. Mingsen, K. Nakagawa, and F. Parisot. An overview of the global observing systems relevant to GODAE. Oceanography, 22(3):22-33 (2009).

A global ocean observing system for the physical climate system, comprising both in situ and satellite components, was conceived largely at the Ocean Observations conference in St. Raphael, France, in October 1999. It was recognized that adequate information was not available on the state of the world ocean or its regional variations to address a range of important societal needs. Subsequent work by the marine carbon community and others in the ocean science and operational communities led to an agreed international plan described in the Global Climate Observing System (GCOS) Implementation Plan (GCOS-92, 2004). This foundation observing system was designed to meet climate requirements, but also supports weather prediction, global and coastal ocean prediction, marine hazard warning systems, transportation, marine environment and ecosystem monitoring, and naval applications. Here, we describe efforts made to reach the goals set out in the international plan. Thanks to these efforts, most of the ice-free ocean above 2000 m is now being observed systematically for the first time, and a global repeat hydrographic survey and selected transport measurements supplement these networks. The system is both integrated and composite. It depends upon in situ and satellite networks that measure the same variable using different sensors. In this way, optimum use is made of all available platforms and sensors to maximize coverage and attain maximum accuracy. Wherever feasible, observations are transmitted in real time or near-real time to maximize their utility, from short-term ocean forecasting to estimation of century-long trends. Because our historical knowledge of oceanic variability is limited, we are learning about the sampling requirements and needed accuracies as the system is implemented and exploited. The system will evolve as technology and knowledge improve. The biggest challenge for the greater oceanographic communityincluding both research and operational componentswill be demonstrating impacts and benefits sufficient to justify the funds needed to complete the observing system, as well as to sustain its funding for the long term.

Conzemius, R.J., and M.T. Montgomery. Clarification on the generation of absolute and potential vorticity in mesoscale convective vortices. Atmospheric Chemistry and Physics, 9(19):7591-7605 (2009).

In this paper, we clarify several outstanding issues concerning the predominant mechanism of vorticity generation in mesoscale convective vortices (MCVs) in weak to modest baroclinic environments with nonzero Coriolis parameter. We examine also the corresponding diabatic heating profiles of the convective and stratiform components of the MCS and their effects on the concentration and dilution of PV substance.

Dickey, T., N. Bates, R.H. Byrne, G. Chang, F.P. Chavez, R.A. Feely, A.K. Hanson, D.M. Karl, D. Manov, C. Moore, C.L. Sabine, and R. Wanninkhof. The NOPP O-SCOPE and MOSEAN projects: Advanced sensing for ocean observing systems. Oceanography, 22(2):168-181 (2009).

The National Oceanographic Partnership Program (NOPP) consecutively sponsored the Ocean-Systems for Chemical, Optical, and Physical Experiments (O-SCOPE) and Multi-disciplinary Ocean Sensors for Environmental Analyses and Networks (MOSEAN) projects from 1998 through 2008. The O-SCOPE and MOSEAN projects focused on developing and testing new sensors and systems for autonomous, concurrent measurements of biological, chemical, optical, and physical variables from a diverse suite of stationary and mobile ocean platforms. Design considerations encompassed extended open-ocean and coastal deployments, instrument durability, biofouling mitigation, data accuracy and precision, near-real-time data telemetry, and economythe latter being critical for widespread sensor and system utilization. The complementary O-SCOPE and MOSEAN projects increased ocean sensing and data telemetry capabilities for addressing many societally relevant problems such as global climate change, ocean carbon cycling and sequestration, acidification, eutrophication, anoxia, and ecosystem dynamics, including harmful algal blooms. NOPP support enabled O-SCOPE and MOSEAN to accelerate progress in achieving multiscale, multidisciplinary, sustained observations of the ocean environment. Importantly, both programs produced value-added scientific results, which demonstrated the utility of these new technologies. The NOPP framework fostered strong collaborations among academic, commercial, and government entities, and facilitated technology transfers to the general research community and to long-term observational and observatory programs.

DiNezio, P.N., L.J. Gramer, W.E. Johns, C.S. Meinen, and M.O. Baringer. Observed interannual variability of the Florida Current: Wind forcing and the North Atlantic oscillation. Journal of Physical Oceanography, 39(3):721-736 (2009).

The role of wind stress curl (WSC) forcing in the observed interannual variability of the Florida Current (FC) transport is investigated. Evidence is provided for baroclinic adjustment as a physical mechanism linking interannual changes in WSC forcing and changes in the circulation of the North Atlantic subtropical gyre. A continuous monthly time series of FC transport is constructed using daily transports estimated from undersea telephone cables near 27°N in the Straits of Florida. This 25-yr-long time series is linearly regressed against interannual WSC variability derived from the NCEPNCAR reanalysis. The results indicate that a substantial fraction of the FC transport variability at 3-12-yr periods is explained by low-frequency WSC variations. A lagged regression analysis is performed to explore hypothetical adjustment times of the wind-driven circulation. The estimated lag times are at least 2 times faster than those predicted by linear beta-plane planetary wave theory. Possible reasons for this discrepancy are discussed within the context of recent observational and theoretical developments. The results are then linked with earlier findings of a low-frequency anticorrelation between FC transport and the North Atlantic Oscillation (NAO) index, showing that this relationship could result from the positive (negative) WSC anomalies that develop between 20° and 30°N in the western North Atlantic during high (low) NAO phases. Ultimately, the observed role of wind forcing on the interannual variability of the FC could represent a benchmark for current efforts to monitor and predict the North Atlantic circulation.

Di Nezio, P.N., A.C. Clement, G.A. Vecchi, B.J. Soden, B.P. Kirtman, and S.-K. Lee. Climate response of the equatorial Pacific to global warming. Journal of Climate, 22(18):4873-4892 (2009).

The climate response of the equatorial Pacific to increased greenhouse gases is investigated using numerical experiments from 11 climate models participating in the Intergovernmental Panel on Climate Changes Fourth Assessment Report. Multimodel mean climate responses to CO₂ doubling are identified and related to changes in the heat budget of the surface layer. Weaker ocean surface currents driven by a slowing down of the Walker circulation reduce ocean dynamical cooling throughout the equatorial Pacific. The combined anomalous ocean dynamical plus radiative heating from CO₂ is balanced by different processes in the western and eastern basins: Cloud cover feedbacks and evaporation balance the heating over the warm pool, while increased cooling by ocean vertical heat transport balances the warming over the cold tongue. This increased cooling by vertical ocean heat transport arises from increased near-surface thermal stratification, despite a reduction in vertical velocity. The stratification response is found to be a permanent feature of the equilibrium climate potentially linked to both thermodynamical and dynamical changes within the equatorial Pacific. Briefly stated, ocean dynamical changes act to reduce (enhance) the net heating in the east (west). This explains why the models simulate enhanced equatorial warming, rather than El Niño-like warming, in response to a weaker Walker circulation. To conclude, the implications for detecting these signals in the modern observational record are discussed.

Doney, S.C., I. Lima, R.A. Feely, D.M. Glover, K. Lindsay, N. Mahowald, J.K. Moore, and R. Wanninkhof. Mechanisms governing interannual variability in upper-ocean inorganic carbon system and air-sea CO₂ fluxes: Physical climate and atmospheric dust. Deep-Sea Research, Part II, 56(8-10):640-655 (2009).

We quantify the mechanisms governing interannual variability in the global, upper-ocean inorganic carbon system using a hindcast simulation (1979-2004) of an ecosystem-biogeochemistry model forced with time-evolving atmospheric physics and dust deposition. We analyze the variability of three key, interrelated metrics--air-sea CO₂ flux, surface-water carbon dioxide partial pressure pCO₂, and upper-ocean dissolved inorganic carbon (DIC) inventory--presenting for each metric global spatial maps of the root mean square (rms) of anomalies from a model monthly climatology. The contribution of specific driving factors is diagnosed using Taylor expansions and linear regression analysis. The major regions of variability occur in the Southern Ocean, tropical Indo-Pacific, and Northern Hemisphere temperate and subpolar latitudes. Ocean circulation is the dominant factor driving variability over most of the ocean, modulating surface dissolved inorganic carbon that in turn alters surface-water pCO₂ and air-sea CO₂ flux variability (global integrated anomaly rms of 0.34 Pg C yr^-1). Biological export and thermal solubility effects partially damp circulation-driven pCO₂ variability in the tropics, while in the subtropics, thermal solubility contributes positively to surface-water pCO₂ and air-sea CO₂ flux variability. Gas transfer and net freshwater inputs induce variability in the air-sea CO₂ flux in some specific regions. A component of air-sea CO₂ flux variability (global integrated anomaly rms of 0.14 Pg C yr^-1) arises from variations in biological export production induced by variations in atmospheric iron deposition downwind of dust source regions. Beginning in the mid-1990s, reduced global dust deposition generates increased air-sea CO₂ outgassing in the Southern Ocean, consistent with trends derived from atmospheric CO₂ inversions.

Dong, S., S.L. Garzoli, and M.O. Baringer. An assessment of the seasonal mixed layer salinity budget in the Southern Ocean. Journal of Geophysical Research, 114(C12):C12001, doi:10.1029/2008JC005258 (2009).

The seasonal cycle of mixed layer salinity and its causes in the Southern Ocean are examined by combining remotely sensed and in situ observations. The domain-averaged terms of oceanic advection, diffusion, entrainment, and air-sea freshwater flux (evaporation minus precipitation) are largely consistent with the seasonal evolution of mixed layer salinity, which increases from March to October and decreases from November to February. This seasonal cycle is largely attributed to oceanic advection and entrainment; air-sea freshwater flux plays only a minimal role. Both oceanic advection-diffusion and the freshwater flux are negative throughout the year, i.e., reduce mixed layer salinity, while entrainment is positive year-round, reaching its maximum in May. The advection-diffusion term is dominated by Ekman advection. Although the spatial structure of the air-sea freshwater flux and oceanic processes are similar for the steady state, the magnitude of the freshwater flux is relatively small when compared to that of the oceanic processes. The spatial structure of the salinity tendency for each month is also well captured by the sum of the contributions from the air-sea freshwater flux, advection-diffusion, and entrainment processes. However, substantial imbalances in the salinity budget exist locally, particularly for regions with strong eddy kinetic energy and sparse in situ measurements. Sensitivity tests suggest that a proper representation of the mixed layer depth, a better freshwater flux product, and an improved surface salinity field are all important for closing the mixed layer salinity budget in the Southern Ocean.

Dong, S., S.L. Garzoli, M.O. Baringer, C.S. Meinen, and G.J. Goni. Interannual variations in the Atlantic Meridional Overturning Circulation and its relationship with the net northward heat transport in the South Atlantic. Geophysical Research Letters, 36(20):L20606, doi:10.1029/2009GL039356 (2009).

Variability of the Atlantic Meridional Overturning Circulation (AMOC) and its effect on the net northward heat transport (NHT) in the South Atlantic are examined using a trans-basin expendable bathythermograph (XBT) high-density line at 35°S (AX18). The time-mean AMOC is 17.9 ± 2.2 Sv during 2002-2007. Although the geostrophic transport dominates the time-mean AMOC, both geostrophic and Ekman transports are important in explaining the AMOC variability. The contributions of geostrophic and Ekman transports to the AMOC show annual cycles, but they are out of phase, resulting in weak seasonal variability of the AMOC. The NHT variability is significantly correlated with the AMOC, where a 1 Sv increase in the AMOC would yield a 0.05 ± 0.01 PW increase in the NHT. Partition of transport into the western and eastern boundaries and interior suggests that, to quantify changes in the AMOC and NHT, it is critical to monitor all three regions.

Dunkerton, T.J., M.T. Montgomery, and Z. Wang. Tropical cyclogenesis in a tropical wave critical layer: Easterly waves. Atmospheric Chemistry and Physics, 9(15):5587-5646 (2009).

The development of tropical depressions within tropical waves over the Atlantic and eastern Pacific is usually preceded by a surface low along the wave as if to suggest a hybrid wave-vortex structure in which flow streamlines not only undulate with the waves, but form a closed circulation in the lower troposphere surrounding the low. This structure, equatorward of the easterly jet axis, resembles the familiar critical layer of waves in shear flow, a flow configuration which arguably provides the simplest conceptual framework for tropical cyclogenesis resulting from tropical waves, their interaction with the mean flow, and with diabatic processes associated with deep moist convection. The critical layer represents a sweet spot for tropical cyclogenesis in which a proto-vortex may form and grow within its parent wave. A common location for storm development within the critical layer is given by the intersection of the waves critical latitude and trough axis, with analyzed vorticity centroid nearby. The wave and vortex live together for a time, and initially propagate at approximately the same speed. In most cases this coupled propagation continues for a few days after a tropical depression is identified. For easterly waves, as the name suggests, the propagation is westward. It is shown that in order to visualize optimally this marsupial paradigm one should view the flow streamlines, or stream function, in a frame of reference translating horizontally with the phase propagation of the parent wave. This translation requires an appropriate gauge that renders translating streamlines and isopleths of translating stream function approximately equivalent to flow trajectories. In the translating frame, the closed circulation is stationary, and a dividing streamline effectively separates air within the critical layer from air outside. The critical layer equatorward of the easterly jet axis is important to tropical cyclogenesis because it provides (i) a region of cyclonic vorticity and weak deformation by the resolved flow, (ii) containment of moisture entrained by the gyre and/or lofted by deep convection therein, (iii) confinement of mesoscale vortex aggregation, (iv) a predominantly convective type of heating profile, and (v) maintenance or enhancement of the parent wave until the vortex becomes a self-sustaining entity and emerges from the wave as a tropical depression. These ideas are formulated in three new hypotheses describing the flow kinematics and dynamics, moist thermodynamics and wave/vortex interactions comprising the marsupial paradigm. A survey of 55 named tropical storms in 1998-2001 reveals that actual critical layers sometimes resemble the ideal east-west train of cats eyes, but are usually less regular, with one or more recirculation regions in the translating frame. It is shown that a wave gauge given by the translation speed of the parent wave is the appropriate choice, as well, for isolated proto-vortices carried by the wave. Some implications for entrainment/containment of vorticity and moisture in the cat's eye are discussed from this perspective, based on the observational survey.

Elipot, S., and S.T. Gille. Ekman layers in the Southern Ocean: Spectral models and observations, vertical viscosity and boundary layer depth. Ocean Science, 5(2):115-139 (2009).

Spectral characteristics of the oceanic boundary-layer response to wind stress forcing are assessed by comparing surface drifter observations from the Southern Ocean to a suite of idealized models that parameterize the vertical flux of horizontal momentum using a first-order turbulence closure scheme. The models vary in their representation of vertical viscosity and boundary conditions. Each is used to derive a theoretical transfer function for the spectral linear response of the ocean to wind stress. The transfer functions are evaluated using observational data. The ageostrophic component of near-surface velocity is computed by subtracting altimeter-derived geostrophic velocities from observed drifter velocities (nominally drogued to represent motions at 15-m depth). Then the transfer function is computed to link these ageostrophic velocities to observed wind stresses. The traditional Ekman model, with infinite depth and constant vertical viscosity is among the worst of the models considered in this study. The model that most successfully describes the variability in the drifter data has a shallow layer of depth O(30-50 m), in which the viscosity is constant and O(100-1000 m² s^-1), with a no-slip bottom boundary condition. The second best model has a vertical viscosity with a surface value O(200 m² s^-1), which increases linearly with depth at a rate O(0.1-1 cm s^-1) and a no-slip boundary condition at the base of the boundary layer of depth O(10³ m). The best model shows little latitudinal or seasonal variability, and there is no obvious link to wind stress or climatological mixed-layer depth. In contrast, in the second best model, the linear coefficient and the boundary layer depth seem to covary with wind stress. The depth of the boundary layer for this model is found to be unphysically large at some latitudes and seasons, possibly a consequence of the inability of Ekman models to remove energy from the system by other means than shear-induced dissipation. However, the Ekman depth scale appears to scale like the climatological mixed-layer depth.

Elipot, S., and S.T. Gille. Estimates of wind energy input to the Ekman layer in the Southern Ocean from surface drifter data. Journal of Geophysical Research, 114(C6):C06003, doi:10.1029/2008JC005170 (2009).

The energy input to the upper ocean Ekman layer is assessed for the Southern Ocean by examining the rotary cross spectrum between wind stress and surface velocity for frequencies between 0 and 2 cpd. The wind stress is taken from European Center for Medium-Range Weather Forecasts ERA-40 reanalysis, and drifter measurements from 15 m depth are used to represent surface velocities, with an adjustment to account for the vertical structure of the upper ocean. The energy input occurs mostly through the nonzero frequencies rather than the mean. Phenomenologically, the combination of a stronger anticyclonic wind stress forcing associated with a greater anticyclonic response makes the contribution from the anticyclonic frequencies dominate the wind energy input. The latitudinal and seasonal variations of the wind energy input to the Ekman layer are closely related to the variations of the wind stress, both for the mean and for the time-varying components. The contribution from the near-inertial band follows a different trend, increasing from 30°S to about 45°S and decreasing further south, possibly a consequence of the lack of variance in this band in the drifter and wind stress data.

Elmir, S.M., T. Shibata, H.M. Solo-Gabriele, C.D. Sinigalliano, M.L. Gidley, G. Miller, L.R.W. Plano, J. Kish, K. Withum, and L.E. Fleming. Quantitative evaluation of enterococci and bacteroidales released by adults and toddlers in marine water. Water Research, 43(18):4610-4616 (2009).

Traditionally, the use of enterococci has been recommended as the fecal indicator bacteria of choice for testing marine recreational water quality, and prior studies have shown that bathers shed large numbers of enterococci into the water. The current study expands upon prior research by evaluating shedding from both toddlers and adults, and by the expansion of measurements to include enterococci shedding via three different methods (membrane filter (MF), chromogenic substrate (CS), and quantitative polymerase chain reaction (qPCR)) and shedding of alternative fecal indicator bacteria (Bacteroidales human markers UCD and HF8 via qPCR). Two sets of experiments were conducted. The first experiment consisted of two groups of 10 adults who bathed together in a large pool. The second study consisted of 14 toddlers who bathed individually in a small pool which allowed for sand recovery. Sand recovery was used to estimate the amount of sand transported on the bodies of toddlers and to estimate the number of fecal indicator bacteria released from this sand. The numbers of estimated enterococci shed per adult ranged from 1.8 x 10⁴ to 2.8 x 10⁶ CFU, from 1.9 x 10³ to 4.5 x 10⁶ MPN, and from 3.8 x 10⁵ to 5.5 x 10⁶ GEU based on the MF, CS, and qPCR methods, respectively. The estimated numbers of Bacteroidales human markers ranged from 1.8 x 10⁴ to 1.3 x 10⁶ for UCD, and ranged from the below detection limit to 1.6 x 10⁵ for HF8. The estimated amount of sand transported per toddler (n = 14) into the water column after sand exposure was 8 ± 6 g on average. When normalizing the numbers of enterococci shed from toddlers via sand by the 3.9 body surface area ratio, the differences between toddlers and adults were insignificant. Contributions of sands to the total enterococci (MF) shed per toddler was 3.7 ± 4.4% on average. Although shedding via beach sand may contribute a small fraction of the microbial load during initial bathing, it may have a significant role if bathers go to water repetitively after sand exposure.

Enfield, D.B., C. Wang, and S.-K. Lee. Cross-hemispheric interactions between variability of the American monsoon systems regions. VAMOS Newsletter, 5:11-14 (2009).

No abstract.

Featherstone, C., J.R. Proni, T.P. Carsey, C. Brown, M. Adler, P. Blackwelder, H. Alsayegh, T. Hood, C. Piela, and D. McCorquodale. Spatial distribution of petroleum hydrocarbons in sediment cores from Blind Pass, St. Pete Beach, Florida. NOAA Technical Memorandum, OAR AOML-97, 252 pp. (CD-ROM) (2009).

One hundred and one sediment cores were collected to characterize the spatial distribution of petroleum hydrocarbons within and just outside Blind Pass, St. Pete Beach, Florida. Twenty-five percent of the cores exhibited levels of petroleum hydrocarbons above detection limits of the gas chromatograph/flame ionization detector (GC/FID) (0.01 mg/Kg), but at generally low concentrations. Petroleum hydrocarbon speciation studies of these samples (gas chromatography/mass spectroscopy [GC/MS]) indicate above-detection level (1 µg/Kg) petroleum hydrocarbons are similar to the non-volatile petroleum hydrocarbons found in a Bouchard 155 reference sample collected after the 1993 oil spill in the area, but are in a much degraded and weathered state. Individual petroleum hydrocarbons were, in all but one case, below the threshold effective level (TEL) described in the literature (MacDonald, 1994). The petroleum hydrocarbons were primarily found at 100-300 cm depth in Blind Pass cores. Above-detection level petroleum hydrocarbons were generally found in samples from cores in the center of the channel, near the edges of the shoal, and just outside of Blind Pass. A second mixture of hydrocarbons, primarily phthalates, ketones, and ether, was found at relatively shallow core depths (0-99 cm) in the Mid- and North End Channel cores. These suggest a separate source of contamination, possibly storm water runoff. The fuel fluorescence detector (FFD) probe was investigated for its ability to detect petroleum hydrocarbons in marine sediments. When analyzed with the FFD, all sediments from the cores produced peaks of fluorescence, but none above the background levels of Blind Pass native sediments. All but two samples analyzed by GC/FID were below the detection limits (100 ppm) of the FFD. These samples were found in dark-colored sediments. The combination of the detection limits of the instrument, sediment color, and the degraded nature of the heavier weight petroleum hydrocarbons may have resulted in fluorescence outputs below background levels. These studies demonstrate that the distribution of petroleum hydrocarbons within Blind Pass sediments is generally low and patchy. However, 25% of the cores exhibited levels above detection using GC/FID/MS. These cores could be subjected to individual speciation studies which indicate generally below TEL levels and an association of some, but not all, with the 1993 oil spill in Blind Pass. Appendix A provides photographs and tables for sediment subsamples which exhibited total petroleum hydrocarbon concentrations above detection limits, while Appendix B presents the results from fuel fluorescence detector probe analyses. A discussion of the results of the study in relation to sediment quality guidelines and soil cleanup target level guidance documents is included as Appendix C. Some preliminary results using the above techniques on core samples from the nearby Johns Pass are presented in Appendix D.

Fierro, A.O., R.F. Rogers, F.D. Marks, and D.S. Nolan. The impact of horizontal grid spacing on the microphysical and kinematic structures of strong tropical cyclones simulated with the WRF-ARW model. Monthly Weather Review, 137(11):3717-3743 (2009).

Using the Advanced Weather Research and Forecasting numerical model, the impact of horizontal grid spacing on the microphysical and kinematic structure of a numerically simulated tropical cyclone (TC), and their relationship to storm intensity was investigated with a set of five numerical simulations using input data for the case of Hurricane Rita (2005). The horizontal grid spacing of the parent domain was systematically changed such that the horizontal grid spacing of the inner nest varied from 1 to 5 km by an increment of 1 km, this while keeping geographical dimensions of the domains identical. Within this small range of horizontal grid spacing, the morphology of the simulated storms and the evolution of the kinematic and microphysics field showed noteworthy differences. As grid spacing increased, the model produced a wider, more tilted eyewall, a larger radius of maximum winds, and higher-amplitude, low wavenumber eyewall asymmetries. The coarser-resolution simulations also produced larger volume, areal coverage, and mass flux of updraft speeds �5 m s^-1; larger volumes of condensate and ice-phase particles aloft; larger boundary layer kinetic energy; and a stronger secondary circulation. While the contribution of updrafts �5 m s^-1 to the total updraft mass flux varied little between the five cases, the contribution of downdrafts �2 m s^-1 to the total downdraft mass flux was by far the largest in the finest-resolution simulation. Despite these structural differences, all of the simulations produced storms of similar intensity, as measured by peak 10-m wind speed and minimum surface pressure, suggesting that features in the higher-resolution simulations that tend to weaken TCs (i.e., smaller area of high surface fluxes and weaker total updraft mass flux) compensate for features that favor TC intensity (i.e., smaller-amplitude eyewall asymmetries and larger radial gradients). This raises the possibility that resolution increases in this range may not be as important as other model features (e.g., physical parameterization and initial condition improvements) for improving TC intensity forecasts.

Fierro, A.O., J. Simpson, M.A. LeMone, J.M. Straka, and B.F. Smull. On how hot towers fuel the Hadley cell: An observational and modeling study of line-organized convection in the equatorial trough from TOGA COARE. Journal of the Atmospheric Sciences, 66(9):2730-2746 (2009).

An airflow trajectory analysis was carried out based on an idealized numerical simulation of the nocturnal 9 February 1993 equatorial oceanic squall line observed over the Tropical Ocean and Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE) ship array. This simulation employed a nonhydrostatic numerical cloud model, which features a sophisticated 12-class bulk microphysics scheme. A second convective system that developed immediately south of the ship array a few hours later under similar environmental conditions was the subject of intensive airborne quad-Doppler radar observations, allowing observed airflow trajectories to be meaningfully compared to those from the model simulation. The results serve to refine the so-called hot tower hypothesis, which postulated the notion of undiluted ascent of boundary layer air to the high troposphere, which has for the first time been tested through coordinated comparisons with both model output and detailed observations. For parcels originating ahead (north) of the system near or below cloud base in the boundary layer (BL), the model showed that a majority (>62%) of these trajectories were able to surmount the 10-km level in their lifetime, with about 5% exceeding 14-km altitude, which was near the modeled cloud top (15.5 km). These trajectories revealed that during ascent, most air parcels first experienced a quick decrease of equivalent potential temperature (theta_e) below 5-km MSL as a result of entrainment of lower ambient theta_e air. Above the freezing level, ascending parcels experienced an increase in theta_e with height attributable to latent heat release from ice processes consistent with previous hypotheses. Analogous trajectories derived from the evolving observed airflow during the mature stage of the airborne radar-observed system identified far fewer (~5%) near-BL parcels reaching heights above 10 km than shown by the corresponding simulation. This is attributed to both the idealized nature of the simulation and to the limitations inherent to the radar observations of near-surface convergence in the subcloud layer. This study shows that latent heat released above the freezing level can compensate for buoyancy reduction by mixing at lower levels, thus enabling air originating in the boundary layer to contribute to the maintenance of both local buoyancy and the large-scale Hadley cell despite acknowledged dilution by mixing along updraft trajectories. A tropical hot tower should thus be redefined as any deep convective cloud with a base in the boundary layer and reaching near the upper-tropospheric outflow layer.

Gentemann, C.L., P.J. Minnett, J. Sienkiewicz, M. DeMaria, J. Cummings, Y. Jin, J.D. Doyle, L. Gramer, C.N. Barron, K.S. Casey, and C.J. Donlon. MISST: The Multi-sensor Improved Sea Surface Temperature Project. Oceanography, 22(2):76-87 (2009).

Sea surface temperature (SST) measurements are vital to global weather prediction, climate change studies, fisheries management, and a wide range of other applications. Measurements are taken by several satellites carrying infrared and microwave radiometers, moored buoys, drifting buoys, and ships. Collecting all these measurements together and producing global maps of SST has been a difficult endeavor due in part to different data formats, data location and accessibility, and lack of measurement error estimates. The need for a uniform approach to SST measurements and estimation of measurement errors resulted in the formation of the international Global Ocean Data Assimilation Experiment (GODAE) High Resolution SST Pilot Project (GHRSST-PP). Projects were developed in Japan, Europe, and Australia. Simultaneously, in the United States, the Multi-sensor Improved SST (MISST) project was initiated. Five years later, the MISST project has produced satellite SST data from nine satellites in an identical format with ancillary information and estimates of measurement error. Use of these data in global SST analyses has been improved through research into modeling of the ocean surface skin layer and upper ocean diurnal heating. These data and research results have been used by several groups within MISST to produce high-resolution global maps of SSTs, which have been shown to improve tropical cyclone prediction. Additionally, the new SSTs are now used operationally for marine weather warnings and forecasts.

Gledhill, D.K., R. Wanninkhof, and C.M. Eakin. Observing ocean acidification from space. Oceanography, 22(4):48-60 (2009).

Space-based observations provide synoptic coverage of surface ocean temperature, winds, sea surface height, and color useful to a wide range of oceanographic applications. These measurements are increasingly applied to monitor large-scale environmental and climate processes that can have an impact on important managed marine resources. From observing the development of harmful algal blooms using ocean color to tracking regions of thermal stress that can induce coral bleaching, satellites are routinely used for environmental monitoring. Here, we demonstrate an approach to monitoring changes in sea surface ocean chemistry in response to ocean acidification as applied to the greater Caribbean region. The method is based on regionally specific empirical algorithms derived from ongoing ship measurements applied to remotely sensed observables. This tool is important for exploring regional to basinwide trends in ocean acidification on seasonal to interannual time scales.

Goni, G.J., and J.A. Knaff. Tropical cyclone heat potential. In State of the Climate in 2008, T.C. Peterson and M.O. Baringer (eds.). Bulletin of the American Meteorological Society, 90(8):S54-S57 (2009).

No abstract.

Goni, G.J., M. DeMaria, J. Knaff, C. Sampson, I. Ginis, F. Bringas, A. Mavume, C. Lauer, I.-I. Lin, M.M. Ali, P. Sandery, S. Ramos-Buarque, K. Kang, A. Mehra, E. Chassignet, and G.R. Halliwell. Applications of satellite-derived ocean measurements to tropical cyclone intensity forecasting. Oceanography, 22(3):191-197 (2009).

Sudden tropical cyclone (TC) intensification has been linked with high values of upper ocean heat content contained in mesoscale features, particularly warm ocean eddies, provided that atmospheric conditions are also favorable. Although understanding of air-sea interaction for TCs is evolving, this manuscript summarizes some of the current work being carried out to investigate the role that the upper ocean plays in TC intensification and the use of ocean parameters in forecasting TC intensity.

Goodwin, K.D., and M. Pobuda. Performance of CHROMagar^TM Staph aureus and CHROMagar^TM MRSA for detection of Staphylococcus aureus in seawater and beach sand: Comparison of culture, agglutination, and molecular analyses. Water Research, 43(19):4802-4811 (2009).

Beach seawater and sand were analyzed for Staphylococcus aureus and methicillin resistant S. aureus (MRSA) for samples collected from Avalon, and Doheny Beach, CA. Membrane filtration followed by incubation on CHROMagar Staph aureus (SCA) and CHROMagar MRSA (C-MRSA) was used to enumerate S. aureus and MRSA, respectively. Media performance was evaluated by comparing identification via colony morphology and latex agglutination tests to PCR (clfA, 16S, and mecA genes). Due to background color and crowding, picking colonies from membrane filters and streaking for isolation were sometimes necessary. The specificity of SCA and C-MRSA was improved if colony isolates were identified by the presence of a matte halo in addition to mauve color; however routine agglutination testing of isolates did not appear warranted. Using the appearance of a colony on the membrane filter in conjunction with isolate appearance, the positive % agreement, the negative % agreement, and the % positive predictive accuracy for SCA was 84%, 95%, and 99% respectively, and for C-MRSA it was 85%, 98%, and 92%, respectively. Sensitivity and specificity of SCA and C-MRSA with membrane-filtered beach samples were optimized through identification experience, control of filter volume and incubation time, and isolation of colonies needing further identification. With optimization, SCA and C-MRSA could be used for enumeration of S. aureus and MRSA from samples of beach water and sand. For the sites studied here, the frequency of detection of S. aureus ranged from 60 to 76% and 53 to 79% for samples of beach seawater and sand, respectively. The frequency of detection of MRSA ranged from 2 to 9% and 0 to 12% for samples of seawater and sand, respectively.

Goodwin, K.D., L. Matragrano, D. Wanless, C.D. Sinigalliano, and M.J. LaGier. A preliminary investigation of fecal indicator bacteria, human pathogens, and source tracking markers in beach water and sand. Environmental Research Journal, 2(4):395-417 (2009).

Data suggesting that fecal indicating bacteria may persist and/or regrow in sand has raised concerns that fecal indicators may become uncoupled from sources of human fecal pollution. To investigate this possibility, wet and dry beach sand, beach water, riverine water, canal water, and raw sewage samples were screened by PCR for certain pathogenic microbes and molecular markers of human fecal pollution. The targets included in this study were human specific Bacteroides (HF8 marker), human-specific enterococci (esp gene), Staphylococcus aureus, Escherichia coli 0157:H7, Campylobacter jejuni, and adenovirus. Sewage samples were also tested for Salmonella species. The results were compared to concentrations of enterococci, Escherichia coli, and Bacteroides species, as determined by membrane filtration methods. Molecular analysis yielded positive results for human specific Bacteroides, and S. aureus, in samples of raw sewage. Two of the environmental samples were positive for human specific Bacteroides and one was positive for S. aureus. The PCR screen was negative for other samples and targets, despite exceedance of EPA single sample guidelines for recreational waters on several of the sample dates (5/11 dates). However, estimates of the number of cells delivered to the PCR reaction suggested that few of the samples met the detection limit of the PCR reaction due to a variety of factors. The analysis indicated a need to improve nucleic acid processing in order to enable better delivery of DNA to downstream molecular methods.

Gramer, L.J., E.M. Johns, J.C. Hendee, and C. Hu. Characterization of biologically significant hydrodynamic anomalies on the Florida Reef Tract. Proceedings, 11th International Coral Reef Symposium, Ft. Lauderdale, FL, July 7-11, 2008. International Society for Reef Studies, 470-474 (2009). (peer reviewed)

The U.S. National Oceanic and Atmospheric Administration (NOAA) Integrated Coral Observing Network (ICON) Project uses artificial-intelligence software to implement heuristic models of coral reef ecosystem response to physical conditions. These models use if-then rules to recognize patterns in environmental data integrated in near real-time from multiple sources. One model is described to detect episodic, biologically significant fluxes acting upon coral reefs in the Florida Reef Tract. Data are gathered from in situ sensors and satellites for three sites near the reef crest: Sombrero Key in the Middle Keys, Molasses Reef in the Upper Keys, and Fowey Rocks off Miami. The model recognizes apparent circulation changes that may impact reef ecology. Criteria are in situ sea-temperature variability at near-tidal frequencies, wind velocity variability, and color-derived satellite chlorophyll-a point data. Model ecological forecasts (ecoforecasts) are verified using secondary data not input to the model, including satellite ocean-color imagery, radar-derived ocean surface currents, and divers reports. Events are characterized as being one of wind-driven upwelling; net transport of eutrophic water from outside the FRT; and interaction of Florida Current frontal features with reef topography, possibly modulated by internal wave-breaking. Multiple events are characterized in a 42-month period in 2005-2008.

Guilyardi, E., A. Wittenberg, A. Fedorov, M. Collins, C. Wang, A. Capotondi, G.J. van Oldenborgh, and T. Stockdale. Understanding El Niño in ocean-atmosphere general circulation models: Progress and challenges. Bulletin of the American Meteorological Society, 90(3):325-340 (2009).

Determining how El Niño and its impacts may change over the next 10 to 100 years remains a difficult scientific challenge. Ocean-atmosphere coupled general circulation models (CGCMs) are routinely used both to analyze El Niño mechanisms and teleconnections and to predict its evolution on a broad range of time scales, from seasonal to centennial. The ability to simulate El Niño as an emergent property of these models has largely improved over the last few years. Nevertheless, the diversity of model simulations of present-day El Niño indicates current limitations in our ability to model this climate phenomenon and to anticipate changes in its characteristics. A review of the several factors that contribute to this diversity, as well as potential means to improve the simulation of El Niño, is presented.

Halliwell, G.R., A. Barth, R.H. Weisberg, P. Hogan, O.M. Smedstad, and J. Cummings. Impact of GODAE products on nested HYCOM simulations of the West Florida Shelf. Ocean Dynamics, 59(1):139-155 (2009).

Nested non-assimilative simulations of the West Florida Shelf for 2004-2005 are used to quantify the impact of initial and boundary conditions provided by Global Ocean Data Assimilation Experiment ocean products. Simulations are nested within an optimum interpolation hindcast of the Atlantic Ocean, the initial test of the U.S. Navy Coupled Ocean Data Assimilation system for the Gulf of Mexico, and a global ocean hindcast that used the latter assimilation system. These simulations are compared to one that is nested in a non-assimilative Gulf of Mexico model to document the importance of assimilation in the outer model. Simulations are evaluated by comparing model results to moored Acoustic Doppler Current Profiler measurements and moored sea surface temperature time series. The choice of outer model has little influence on simulated velocity fluctuations over the inner and middle shelf where fluctuations are dominated by the deterministic wind-driven response. Improvement is documented in the representation of alongshore flow variability over the outer shelf, driven in part by the intrusion of the Loop Current and associated cyclones at the shelf edge near the Dry Tortugas. This improvement was realized in the simulation nested in the global ocean hindcast, the only outer model choice that contained a realistic representation of Loop Current transport associated with basin-scale wind-driven gyre circulation and the Atlantic Meridional Overturning Circulation. For temperature, the non-assimilative outer model had a cold bias in the upper ocean that was substantially corrected in the data-assimilative outer models, leading to improved temperature representation in the simulations nested in the assimilative outer models.

Hendee, J.C., L.J. Gramer, D. Manzello, and M. Jankulak. Ecological forecasting for coral reef ecosystems. Proceedings, 11th International Coral Reef Symposium, Ft. Lauderdale, FL, July 7-11, 2008. International Society for Reef Studies, 534-538 (2009). (peer reviewed)

Assessment of coral reef ecosystems implies the acquisition of precision data and observations appropriate for answering questions about the response of multiple organisms to physical and other environmental stimuli. At the National Oceanic and Atmospheric Administrations Atlantic Oceanographic and Meteorological Laboratory, we model marine organismal response to the environment in terms of a Stimulus/Response Index (S/RI). S/RI is computed using an approach called heuristic programming, from parameters bounded in subjective terms, which are defined numerically by comparing historical data with expert opinion, so as to match research and our understanding of the process in question. The modeled organismal response is called an ecological forecast, or ecoforecast, and relative possibility and intensity of the response is reflected in a rising S/RI. We have had success to date in modeling coral bleaching response to high sea temperatures plus high irradiance and other parameters. The approach requires, a) highly robust instrumentation (in situ, satellite, or other) deployed for long periods and producing high quality data in near real-time, b) a basic understanding of the process, behavior and/or physiology being modeled, and, c) a knowledge of approximate threshold levels for single or synergistically acting environmental parameters that elicit the phenomenon in question.

Heymsfield, A.J., A. Bansemer, G. Heymsfield, and A.O. Fierro. Microphysics of maritime tropical convective updrafts at temperatures from -20° to-60°. Journal of the Atmospheric Sciences, 66(12):3530-3562 (2009).

Anvils produced by vigorous tropical convection contribute significantly to the earths radiation balance, and their radiative properties depend largely on the concentrations and sizes of the ice particles that form them. These microphysical properties are determined to an important extent by the fate of supercooled droplets, with diameters from 3 to about 20 microns, lofted in the updrafts. The present study addresses the question of whether most or all of these droplets are captured by ice particles or if they remain uncollected until arriving at the -38°C level where they freeze by homogeneous nucleation, producing high concentrations of very small ice particles that can persist and dominate the albedo. Aircraft data of ice particle and water droplet size distributions from seven field campaigns at latitudes from 25°N to 11°S are combined with a numerical model in order to examine the conditions under which significant numbers of supercooled water droplets can be lofted to the homogeneous nucleation level. Microphysical data were collected in pristine to heavily dust-laden maritime environments, isolated convective updrafts, and tropical cyclone updrafts with peak velocities reaching 25 m s^-1. The cumulative horizontal distance of in-cloud sampling at temperatures of 20°C and below exceeds 50 000 km. Analysis reveals that most of the condensate in these convective updrafts is removed before reaching the 20°C level, and the total condensate continues to diminish linearly upward. The amount of condensate in small (<50 µm in diameter) droplets and ice particles, however, increases upward, suggesting new droplet activation with an appreciable radiative impact. Conditions promoting the generation of large numbers of small ice particles through homogeneous ice nucleation include high concentrations of cloud condensation nuclei (sometimes from dust), removal of most of the water substance between cloud base and the 38°C levels, and acceleration of the updrafts at mid- and upper levels such that velocities exceed 5-7 m s^-1.

Hu, C., F. Muller-Karger, B. Murch, D. Myhre, J. Taylor, R. Luerssen, C. Moses, C. Zhang, L. Gramer, and J. Hendee. Building an automated integrated observing system to detect sea surface temperature anomaly events in the Florida Keys. IEEE Transactions on Geoscience and Remote Sensing, 47(6):1607-1620 (2009).

Satellite-derived sea surface temperature (SST) images have had limited applications in near-shore and coastal environments due to inadequate spatial resolution, incorrect geocorrection, or cloud contamination. We have developed a practical approach to remove these errors using AVHRR and MODIS 1-km resolution data. The objective was to improve the accuracy of SST anomaly estimates in the Florida Keys and to provide the best quality (in particular, high temporal and spatial resolutions) SST data products for this region. After manual navigation of over 47,000 AVHRR images collected between September 1993 and December 2005, we implemented a cloud-filtering technique that differs from previously published image processing methods. The filter used a 12-year climatology and ±3 day running SST statistics to flag cloud-contaminated pixels. Comparison with concurrent (±0.5 hour) data from the SEAKEYS in situ stations in the Florida Keys showed near-zero bias errors (<0.05°C) in the weekly anomaly for SST anomalies between -3 and 3°C, with standard deviations <0.5°C. The cloud filter was implemented using IDL for near real-time processing of AVHRR and MODIS imagery. The improved SST products were used to detect SST anomalies and to estimate degree-heating-weeks (DHWs) to assess the potential for coral reef stress. The mean, anomaly, and DHW products are updated weekly and accessible on a web site. The SST data at specific geographical locations were also automatically ingested in near real-time into NOAAs Integrated Coral Observing Network (ICON) web-based application to assist in management and decision-making through a novel expert system tool (G2) implemented at NOAA.

Huang, X.-L., and J.-Z. Zhang. Neutral persulfate digestion at sub-boiling temperature in an oven for total dissolved phosphorus determination in natural waters. Talanta, 78(3):1129-1135 (2009).

A simplified, easily performed persulfate digestion method has been developed to process a large number of water samples for routine determination of total dissolved phosphorus. A neutral potassium persulfate solution (5%, w/v, pH ~6.5) is added to the samples (at 10 mg potassium persulfate per mL of sample), which are then digested at 90°C in an oven for 16 h. This method does not require pH adjustment after digestion because neither an acid nor a base is added to the samples prior to digestion. The full color of phosphoantimonylmolybdenum blue from the digested samples develops within 8 min. Compared with the autoclave method, digestion at sub-boiling temperatures in an oven is safer, and a large number of samples can be heated overnight requiring no constant monitoring. The apparent molar absorptivity (epsilon) of nine organic phosphorus compounds and two condensed inorganic phosphates ranged from 1.17 x 10⁴ to 1.82 x 10⁴L mol^-1 cm^-1 in both distilled water and artificial seawater matrixes. The average recovery of these phosphorus compounds was 94 ± 11% for the DIW matrix and 90 ± 12% for the ASW matrix. No significant difference in molar absorptivity was observed between the undigested and digested phosphate, especially in the seawater matrix. It is, therefore, suggested that a phosphate solution be directly employed without digestion as the calibration standard for routine determination of total dissolved phosphorus. This method was used to study the spatial distribution of total dissolved phosphorus in the surface waters of Florida Bay.

Jankulak, M., J.C. Hendee, and M. Shoemaker. The instrumental architecture of a Coral Reef Early Warning System (CREWS) station. Proceedings, 11th International Coral Reef Symposium, Ft. Lauderdale, FL, July 7-11, 2008. International Society for Reef Studies, 544-548 (2009). (peer reviewed)

The Integrated Coral Observing Network (ICON) program has constructed and installed a series of Coral Reef Early Warning System (CREWS) stations which provide a wealth of high-quality meteorological and oceanographic data in near real-time. CREWS stations date back to 2001 with the deployment of an early buoy-type design in the Bahamas. Beginning in 2002, the program shifted to a pylon-type design which was reengineered in 2005, resulting in the modern CREWS stations found in the Bahamas, Puerto Rico, the U.S. Virgin Islands and Jamaica. The CREWS instrumentation architecture described herein has evolved over time into a robust package that, combined with a regimen of regular instrument cleaning and recalibration, has yielded a continuous, long-term, high-quality dataset from these harsh marine environments.

Johnson, G.C., J.M. Lyman, J.K. Willis, S. Levitus, T. Boyer, J. Antonov, C. Schmid, and G.J. Goni. Ocean heat content. In State of the Climate in 2008, T.C. Peterson and M.O. Baringer (eds.). Bulletin of the American Meteorological Society, 90(8):S49-S52 (2009).

No abstract.

Jones, R.W., H.E. Willoughby, and M.T. Montgomery. Alignment of hurricane-like vortices on f- and beta-planes. Journal of the Atmospheric Sciences, 66(6):1779-1792 (2009).

A nonlinear, two-layer, vortex-tracking semispectral model (i.e., Fourier transformed in azimuth only) is used to study the evolution of dry, but otherwise hurricane-like, initially tilted vortices in quiescent surroundings on f and beta planes. The tilt projects onto vorticity asymmetries that are dynamically vortex Rossby waves. Since the swirling wind in the principal mean vortex used here decays exponentially outside the eyewall, it has an initial potential vorticity (PV) minimum. The resulting reversal of PV gradient meets the necessary condition for inflectional (i.e., barotropic or baroclinic) instability. Thus, the vortex may be inflectionally stable or unstable. On an f plane, the tilt precesses relatively slowly because the critical radius, where the phase speeds of the waves match the mean swirling flow, is far from the center. An alternative Gaussian-like PV monopole that has a monotonic outward decrease of PV is stable to inflectional instability. It has a smaller critical radius and rapid tilt precession. Generally, vortices with fast tilt precession are more stable, as are stronger vortices in higher latitudes. On a beta plane, the interaction between the symmetric vortex and the planetary PV gradient induces beta gyres that push the vortex poleward and westward. The interaction between the beta gyres and the planetary PV gradient may either create a PV minimum or intensify a minimum inherited from the initial condition. Thus, the nonlinear beta effect reduces the ability of the vortex to recover from initial tilt, relative to the same vortex on an f plane. This result contrasts with previous studies of barotropic vortices on f planes, where the linear and nonlinear solutions were nearly identical.

Katzberg, S.J., and J.P. Dunion. Comparison of reflected GPS wind speed retrievals with dropsondes in tropical cyclones. Geophysical Research Letters, 36(17):L17602, doi:10.1029/2009GL039512 (2009).

In an earlier communication, data were presented that demonstrated that quasi-specular, L-Band reflection measurements could be used to infer ocean surface winds. Applying an indirect calibration technique, a mean square slope versus surface wind speed was developed and reported. Retrievals using this calibration showed that the resulting surface wind speeds were comparable with other measurements. This report extends the previous results by presenting direct comparisons between GPS dropwindsonde (dropsonde)-reported wind speeds and the Bi-static GPS wind speed retrievals for data sets acquired in 2008. Editing of the Bi-static GPS data will be discussed that takes into effect overland and inside-the-eye winnowing. Data will be presented with a regression line to determine the comparative relationship. It will be shown that good agreement exists between the reflected Bi-static GPS retrieved winds and those reported by the dropsondes when certain well-defined types of data are excluded.

Lee, S.-K., C. Wang, and B.E. Mapes. A simple atmospheric model of the local and teleconnection responses to tropical heating anomalies. Journal of Climate, 22(2):272-284 (2009).

A minimal complexity model of both the local and remote stationary responses of the atmosphere to tropical heating anomalies is described and demonstrated. Two levels are recast as baroclinic and barotropic components with thermal advection in the tropics neglected. The model is linearized about some idealized and realistic background wind fields and forced with a localized heating for illustration. In the tropics, the baroclinic responses are familiar from the Matsuno-Gill model; these excite barotropic responses by advective interactions with vertical background wind shear. The barotropic signals are in turn transmitted to high latitudes only in the presence of barotropic background westerly winds. For an El Niño-like equatorial heating, the barotropic response has anticyclones to the north and south of the heating reinforcing (opposing) the anticyclonic (cyclonic) baroclinic gyres in the upper (lower) troposphere. With realistic background flows, the model reproduces the hemispheric asymmetry of ENSO teleconnections. Further experiments show that the winter hemisphere is favored mainly because the summer hemispheric subtropical jet is farther from the heating latitude, suggesting that the summer hemisphere can still host robust stationary Rossby waves if the heating occurs in the vicinity of the jet. As an example, it is shown that summer heating over the Atlantic warm pool (AWP) can have a remote influence on the summer climate of North America and Europe.

Lirman, D., and D.P. Manzello. Patterns of resistance and resilience of the stress-tolerant coral Siderastrea radians (Pallas) to sub-optimal salinity and sediment burial. Journal of Experimental Marine Biology and Ecology, 369(1):72-77 (2009).

The coastal lagoons of south Florida, U.S., experience fluctuating levels of sedimentation and salinity and contain only a subset of the coral species found at the adjacent reefs of the Florida Reef Tract. The dominant species within these habitats is Siderastrea radians, which can reach densities of up to 68 colonies m^-2 and is commonly exposed to salinity extremes (< 10 psu to > 37 psu) and chronic sediment burial. In this study, we document the patterns of resistance and resilience of S. radians to sub-optimal salinity levels and sediment burial in a series of short-term, long-term, acute, chronic, single-stressor, and sequential-stressor experiments. S. radians displayed remarkable patterns of resistance and resilience, and mortality was documented only under prolonged (> 48 h) continuous exposure to salinity extremes (15 and 45 psu) and chronic sediment burial. A reduction in photosynthetic rates was documented for all salinity exposures and the decrease in photosynthesis was linearly related to exposure time. Negative impacts on photosynthetic rates were more severe under low salinity (15 psu) than under high salinity (45 psu). Corals exposed to intermediate, low-salinity levels (25 psu) exhibited initial declines in photosynthesis that were followed by temporary increases that may represent transient acclimatization patterns. The impacts of sediment burial were influenced by the duration of the burial period and ranged from a temporary reduction in photosynthesis to significant reductions in growth and tissue mortality. The maintenance of P/R ratios >1 and the rapid (<24 h) recovery of photosynthetic rates after burial periods of 2-24 h indicates that S. radians is able to resist short-term burial periods with minor physiological consequences. However, as burial periods increase and colonies become covered at multiple chronic intervals, sediment burial resulted in extended photosynthetic recovery periods, reduced growth, and mortality. Under normal conditions (i.e., no salinity stress), S. radians was very effective at clearing sediments, and >50% of the colonies surface area was cleared within 1 h. However, clearing rates were influenced by physiological status, and prior exposure to sub-optimal salinity significantly reduced the clearing rates of stressed colonies. The response of S. radians to disturbance documented in this study characterizes this species as highly stress-tolerant and provides an explanation for its present high abundance in both reef and marginal environments. Moreover, the key life-history attributes of S. radians, such as brooding reproductive strategy, small colony size, high stress-tolerance, and high recruitment rates, suggest the potential for this species to replace reef-building taxa under increased disturbance scenarios in Florida and elsewhere in the region.

Lumpkin, R., G.J. Goni, and K. Dohan. Surface current observations. In State of the Climate in 2008, T.C. Peterson and M.O. Baringer (eds.). Bulletin of the American Meteorological Society, 90(8):S57-S59 (2009).

No abstract.

Manzello, D.P. Reef development and resilience to acute (El Niño warming) and chronic (high-CO₂) disturbances in the eastern tropical Pacific: A real-world climate change model. Proceedings, 11th International Coral Reef Symposium, Ft. Lauderdale, FL, July 7-11, 2008. International Society for Reef Studies, 1299-1304 (2009). (peer reviewed)

It has been recently recognized that eastern tropical Pacific (ETP) coral reefs exist under naturally occurring high-CO₂, low carbonate saturation (OMEGA) conditions that encompass the range of expected changes for the entire tropical surface ocean with a doubling and tripling of atmospheric CO₂. Holocene reef development positively and linearly tracks OMEGA in the ETP; illustrating the real-world importance of this variable on reef building. Galapagos reef communities have been subject to the most extreme thermal anomalies associated with the El Niño-Southern Oscillation (ENSO) and also experience the lowest OMEGA levels in the ETP. Reef resilience has been so poor in Galapagos that reef structures were completely bioeroded in <10 years after the 1982-83 ENSO. The closure of the Panamanian isthmus 3-3.5 million years ago created the present-day oceanographic conditions responsible for ENSO-related warming events and the upwelling of high-CO₂ waters throughout the ETP. These combined acute (ENSO) and chronic (high-CO₂) disturbances may help explain why coral reefs are scant and many genera of corals went extinct in the ETP during the late Cenozoic; thus providing a real-world example of the combined thermal and chemical ramifications of climate change on coral reef structure, function, and resilience to disturbance over geologic time.

Manzello, D.P., and J.A. Kleypas. Reef development in a high-CO₂ world: Coral reefs of the eastern tropical Pacific. Global Change Newsletter, 73:24 (2009).

No abstract.

Manzello, D.P. M. Warner, E. Stabenau, J. Hendee, M. Lesser, and M. Jankulak. Remote monitoring of chlorophyll fluorescence in two reef corals during the 2005 bleaching event at Lee Stocking Island, Bahamas. Coral Reefs, 28(1):209-214 (2009).

Zooxanthellae fluorescence was measured in situ, remotely, and in near real-time with a pulse amplitude modulated (PAM) fluorometer for a colony of Siderastrea siderea and Agaricia tenuifolia at Lee Stocking Island, Bahamas during the Caribbean-wide 2005 bleaching event. These colonies displayed evidence of photosystem II (PS II) inactivation coincident with thermal stress and seasonally high doses of solar radiation. Hurricane-associated declines in temperature and light appear to have facilitated the recovery of maximum quantum yield of PS II within these two colonies, although both corals responded differently to individual storms. PAM fluorometry, coupled with long-term measurement of in situ light and temperature, provides much more detail of coral photobiology on a seasonal time scale and during possible bleaching conditions than sporadic, subjective, and qualitative observations. S. siderea displayed evidence of PS II inactivation over a month prior to the issuing of a satellite-based, sea surface temperature (SST) bleaching alert by the National Oceanic and Atmospheric Administration (NOAA). In fact, recovery had already begun in S. siderea when the bleaching alert was issued. Fluorescence data for A. tenuifolia were difficult to interpret because the shaded parts of a colony were monitored and thus did not perfectly coincide with thermal stress and seasonally high doses of solar radiation as in S. siderea. These results further emphasize the limitations of solely monitoring SST (satellite or in situ) as a bleaching indicator without considering the physiological status of coral-zooxanthellae symbioses.

Marshall, J., A. Andersson, N. Bates, W. Dewar, S. Doney, J. Edson, R. Ferrari, G. Forget, D. Fratantoni, M. Gregg, T. Joyce, K. Kelly, S. Lozier, R. Lumpkin, G. Maze, J. Palter, R. Samelson, K. Silverthorne, E. Skyllingstad, F. Straneo, L. Talley, L. Thomas, J. Toole, and R. Weller. The Climode field campaign: Observing the cycle of convection and restratification over the Gulf Stream. Bulletin of the American Meteorological Society, 90(9):1337-1350 (2009).

A major oceanographic field experiment is described, which is designed to observe, quantify, and understand the creation and dispersal of weakly stratified fluid known as mode water in the region of the Gulf Stream. Formed in the wintertime by convection driven by the most intense airsea fluxes observed anywhere over the globe, the role of mode waters in the general circulation of the subtropical gyre and its biogeo-chemical cycles is also addressed. The experiment is known as the CLIVAR Mode Water Dynamic Experiment (CLIMODE). Here we review the scientific objectives of the experiment and present some preliminary results.

Masutani, M., R. Atlas, et al. Expanding collaboration in joint OSSEs. Preprint Volume, 13th Conference on Integrated Observing and Assimilation Systems for the Atmosphere, Oceans, and Land Surface, Phoenix, AZ, January 11-15, 2009. American Meteorological Society, Boston, 6 pp. (2009).

No abstract.

Meinen, C.S., D.S. Luther, and M.O. Baringer. Structure, transport, and potential vorticity of the Gulf Stream at 68°W: Revisiting older data sets with new techniques. Deep-Sea Research, Part I, 56(1):41-60 (2009).

The stream-coordinates mean structure of the Gulf Stream at 68°W is derived using new methods for both defining stream coordinates and interpreting bottom pressure and inverted echo sounder travel times collected during the extensive Synoptic Ocean Prediction Experiment. These new analyses provide pictures of the vertical structure of Gulf Stream flows that are demonstrably dynamically consistent with the density field at all depths, in contrast to previous work that relies on simple vertical interpolations to fill gaps between sparse current meter measurements. This new view of the Gulf Stream suggests a slightly higher total mean transport, with the increases coming from both baroclinic and barotropic components, and slightly stronger recirculation cells, particularly on the southern side. The recirculation of the Gulf Stream appears to have a weak baroclinic component, perhaps 10% of the total. A significant advantage of the methodology is the ability to obtain sensible vertical and horizontal gradients of currents and density so that the vertical and cross-stream structures of the components of the mean potential vorticity can be clearly imaged. One new feature from this calculation is that the along-stream gradient of the cross-stream velocity, a term that is often ignored in potential vorticity analyses, is non-negligible (though small) and is asymmetric about the current axis. Both the derived structure and implied dynamics of the circulation can be significantly altered by small changes to the method of calculating daily stream coordinates, e.g., by carefully filtering out observations in rings or not. Arrays of pressure-equipped inverted echo sounders provide the opportunity (at reasonable cost) for properly defining the stream coordinates of energetic jets such as the Gulf Stream.

Montgomery, M.T., V.S. Nguyen, R.K. Smith, and J. Persing. Do tropical cyclones intensity by WISHE? Quarterly Journal of the Royal Meteorological Society, 135(644):1697-1714 (2009).

In this paper we seek and obtain a basic understanding of tropical cyclone intensification in three dimensions when precipitation and evaporative-cooling (warm rain) processes are included. Intensification with warm rain physics included is found to be dominated by highly localized deep convective structures possessing strong cyclonic vorticity in their cores, dubbed "Vortical Hot Towers" (VHTs). Unlike previous studies, the findings herein suggest an intensification pathway that is distinct from the "evaporation-wind" feedback mechanism known as wind-induced surface heat exchange (WISHE), which requires a positive feedback between the azimuthal-mean boundary-layer equivalent potential temperature and the azimuthal-mean surface wind speed underneath the eyewall of the storm. Intensification from a finite-amplitude initial vortex is shown to not require this evaporation-wind feedback process. Indeed, when the surface wind speed in the sea-to-air vapour fluxes is capped at a nominal (trade-wind) value, the vortex still intensifies by the same pathway identified in the main experiments via the generation of locally buoyant VHTs and the near-surface convergence that the VHTs induce within the boundary layer. The present findings and interpretations challenge the prevailing view that tropical cyclones are premier examples of vortical systems arising from WISHE. Given the potential significance on our understanding of the dynamics of hurricanes, and given the limitations of the present modelling framework, further tests of these predictions are advocated.

Nolan, D.S., J.A. Zhang, and D.P. Stern. Evaluation of planetary boundary layer parameterizations in tropical cyclones by comparison of in-situ observations and high-resolution simulations of Hurricane Isabel (2003), Part I: Initialization, maximum winds, and the outer core boundary layer. Monthly Weather Review, 137(11):3651-3674 (2009).

In this study, the first of two parts, the planetary boundary layer (PBL) depicted in high-resolution Weather Research and Forecast Model (WRF) simulations of Hurricane Isabel (2003) is studied and evaluated by direct comparisons with in situ data obtained during the Coupled Boundary Layer and Air-Sea Transfer Experiment (CBLAST). In particular, two boundary layer schemes are evaluated: the Yonsei University (YSU) parameterization and the Mellor-Yamada-Janjic (MYJ) parameterization. Investigation of these schemes is useful since they are available for use with WRF, are both widely used, and are based on entirely different methods for simulating the PBL. In this first part, the model domains and initialization are described. For additional realism of the low-level thermodynamic environment, a simple mixed layer ocean model is used to simulate ocean cooling. The YSU and MYJ schemes are discussed, along with some modifications. Standard measures of the accuracy of the hurricane simulations, such as track, maximum surface wind speed, and minimum surface pressure are described for a variety of parameter choices and for the two parameterizations. The effects on track and intensity of increased horizontal and vertical resolutions are also shown. A modification of the original YSU and MYJ schemes to have ocean roughness lengths more in agreement with recent studies considerably improves the results of both schemes. Instantaneous wind maxima on the innermost grid with 1.33-km resolution are shown to be an accurate representation of the simulated 1-min sustained winds. The simulated boundary layers are evaluated by direct comparison of the PBL as simulated and as observed by in situ data from the CBLAST experiment in the outer core region of the storm. The two PBL schemes and their modified counterparts reproduce the observed PBL remarkably well. Comparisons are also made to the observed vertical fluxes of momentum, heat, and moisture. In Part II, the detailed comparisons of the intensities and structures of the simulated and observed inner-core boundary layers are presented, and the reasons for the differences are discussed.

Nolan, S.D., D.P. Stern, and J.A. ZHANG. Evaluation of planetary boundary layer parameterizations in tropical cyclones by comparison of in-situ observations and high-resolution simulations of Hurricane Isabel (2003), Part II: Inner-core boundary layer and eyewall structure. Monthly Weather Review, 137(11):3675-3698 (2009).

This is the second of a two-part study of the representation of the planetary boundary layer (PBL) in high-resolution Weather Research and Forecast Model (WRF) simulations of Hurricane Isabel (2003). The Yonsei University (YSU) PBL parameterization and the Mellor-Yamada-Janjic (MYJ) PBL parameterization are evaluated by direct comparison to in situ data obtained by research aircraft. The numerical model, simulation design, details of the PBL schemes, and the representation of the boundary layer in the outer-core were presented in Part I. This part presents a detailed study of the inner-core PBL, including its axisymmetric and asymmetric structures, and comparisons to analyses of dropsonde data from previous studies. Although neither PBL scheme was designed specifically for hurricane conditions, their simulated boundary layers are reasonably good representations of the observed boundary layer. Both schemes reproduce certain unique features of the hurricane boundary layer, such as the separate depths of the well-mixed layer and the inflow layer, and the pronounced wind speed maxima near the top of the inflow layer. Modification of the original YSU and MYJ schemes to have ocean roughness lengths more in agreement with recent studies considerably improves the results of both schemes. Even with these improvements, the MYJ consistently produces larger frictional tendencies in the boundary layer than the YSU scheme, leading to a stronger low-level inflow and a stronger azimuthal wind maximum at the top of the boundary layer. For both schemes, differences in the low-level asymmetries between the simulated and observed wind fields appear to be related to eyewall asymmetries forced by environmental wind shear. The effects of varying horizontal and vertical resolutions are also considered. Increasing the vertical resolution in the PBL results in minor improvements in the inner-core structures. Increasing the horizontal resolution around the eyewall also leads to improved boundary layers, as well as an improvement of the vertical structure of the inner-core wind field. A summary and discussion of the results of both Parts I and II is provided.

Palmer, D.R. Coherent and incoherent scattering by a plume of particles advected by turbulent velocity flow. Journal of the Acoustical Society of America, 126(2):587-598 (2009).

Studies of acoustic remote sensing of the plumes that result from the injection of particulate matter in the ocean, either naturally or by dumping or dredging activities, have assumed the scattering is incoherent. These plumes are always turbulent, however. The particle density is a passive scalar that is advected by the turbulent velocity flow. The possibility exists, therefore, that the scattered waves from a significant number of particles add coherently as a result of Bragg scattering. In this paper, we investigate this possibility. We derive an expression for the ratio of the coherent intensity to the incoherent one in terms of the turbulent spectrum and the properties of the particles that make up the plume. The sonar is modeled as a high-Q, monostatic, pulsed sonar with arbitrary pulse envelope and arbitrary, but narrow, beam pattern. We apply the formalism to acoustic remote sensing of black smoker hydrothermal plumes. We find that, at most, the coherent intensity is less than 1% of the incoherent one. The implications are that Bragg scattering does not lead to a significant coherent component and in analyses of scattering from this type of plume, one can ignore the complications of turbulence altogether.

Panda, J., M. Sharan, and S.G. Gopalakrishnan. Study of regional-scale boundary layer characteristics over northern India with a special reference to the role of the Thar Desert in regional-scale transport. Journal of Applied Meteorology and Climatology, 48(11):2377-2402 (2009).

Extensive contrasts of land surface heterogeneities have a pivotal role in modulating boundary layer processes and, consequently, the regional-scale dispersion of air pollutants. The Weather Research and Forecasting (WRF) modeling system has been used to analyze the regional-scale boundary layer features over northern India. Two cases, 9-11 December 2004 and 20-22 May 2005, representing the winter and summer seasons, respectively, are chosen for the simulations. The model results have been compared with the observations from the India Meteorological Department (IMD) and Wyoming Weather Web data archive over three cities: Delhi, Ahmedabad, and Jodhpur. The simulations show that the thermal stratifications and the associated wind patterns are very well supported by land surface characteristics over the region. The results signify that the underlying land surface along with the prevailing hemispheric-scale meteorological processes (synoptic conditions) is the driver of the simulated patterns. The study implies that thermally-driven regional circulations play a major role in the transport of particulate matter from the Thar Desert to Delhi and its neighboring regions during summer.

Pandya, R.E., D.R. Smith, D.J. Charlevoix, W. Hart, M.J. Hayes, S.T. Murillo, K.A. Murphy, D.M. Stanitski, and T.M. Whittaker. A summary of the 16th Symposium on Education. Bulletin of the American Meteorological Society, 90(6):861-865 (2009).

No abstract.

Pandya, R.E., D.R. Smith, D.J. Charlevoix, S.Q. Foster, R. Hart, M.J. Hayes, M. McGuirk, S.T. Murillo, K.A. Murphy, D.M. Stanitski, and T.M. Whittaker. A summary of the 17th AMS Education Symposium. Bulletin of the American Meteorological Society, 90(10):1545-1548 (2009).

No abstract.

Peng, G., Z. Garraffo, G.R. Halliwell, O.M. Smedstad, C.S. Meinen, V. Kourafalou, and P. Hogan. Temporal variability of the Florida Current transport at 27°N. In Ocean Circulation and El Niño: New Research, J.A. Long and D.S. Wells (ed.). Nova Science Publishers, New York, 119-137 (2009).

The variability of the annual cycle of the Florida Current transport and its relationship to the variability of large-scale atmospheric forcing is examined using time series of daily Florida Current transport based on submarine cable voltage measurements from 1982 to 2005. To investigate the impact of large-scale atmospheric forcing variations represented by the North Atlantic Oscillation (NAO), two NAO regimes, strong positive and strong negative, are defined in order to isolate basic characteristics of the annual cycles of the Florida Current transport associated with those two regimes. The strong positive (negative) NAO regime is defined as being when the NAO index is greater (less) than 0.8 (-0.8). A minimum of 30.46 Sv in the Florida Current transport is found in January and a maximum of 33.71 in July with a mean of 32.12 Sv based on daily composites of all cable data, which is consistent with previous studies. A distinct difference between those two opposing NAO regimes occurs in late winter, with a minimum (maximum) for the strong positive (negative) NAOs in March. As for the summer peak, it occurs in May for the strong positive NAOs and in July for the strong negative NAOs, as in the normal year. There is a 5% fluctuation in the mean Florida Current transport values between those two strong NAO regimes. Using daily transport time series for the Florida Current calculated from various model experiments for the year 2004, along with the Florida Current transport derived from cable and in-situ measurements from research cruises, we have shown that the Florida Current transport is not sensitive to the resolution of local atmospheric forcing or to the model vertical resolution. However, the major influence on fluctuations on time scales of a few days to several weeks is found to be linked to basin-scale variability in the North Atlantic Ocean. The decadal variability of the Florida Current transport is examined using a 54-year time series of Florida Current transport anomaly from a 1/3° North Atlantic model simulation. The model Florida Current transport anomaly is found to be loosely correlated with the NAO anomaly. The time series of the sea surface height difference (sshdif) between the subtropical gyre and subpolar gyre, however, is strongly correlated with the NAO anomaly, with NAO leading by about 2.5 years. The results also show that the sshdif is well correlated with the model Florida Current transport anomaly, with sshdif leading by about 3.5 years. This suggests that the decadal variability of the Florida Current transport is largely controlled by the variability of the internal ocean dynamics forced by the NAO variability rather than by the NAO variability itself.

Perez, R.C., and W.S. Kessler. The three-dimensional structure of tropical cells in the central equatorial Pacific Ocean. Journal of Physical Oceanography, 39(1):27-49 (2009).

The shallow tropical cells (TCs) in the central equatorial Pacific Ocean are characterized by strong equatorial upwelling, near-surface wind-driven poleward flow, downwelling near the cold tongue boundaries, and equatorward flow below the surface mixed layer. Meridional and vertical velocity fluctuations associated with tropical instability waves (TIWs) in the central equatorial Pacific are much larger than those associated with the TCs and can modify the background circulation. OGCM experiments are used to simulate the spinup of the cells along 140°W in response to perturbed trade winds during various phases of the annual cycle. Equatorially modified versions of geostrophy and Ekman theory, and zonal filtering, are used to isolate the large-zonal-scale wind-driven response. Weakening of the trade winds in any season rapidly weakens the TCs, decreases the zonal current shear, and reduces the amplitude and propagation speed of the TIWs. In boreal fall and winter, when the background TCs and TIWs are seasonally strong, the ocean response is equatorially asymmetric (stronger flows north of the equator) and there is evidence of rectification by the modified TIWs onto the TCs. The linear equatorially modified Ekman solutions largely explain the meridional structure and temporal evolution of the anomalous ageostrophic response in the TCs. In fall and winter, however, deviations from the modified Ekman solutions were attributed to interactions with the background TCs and TIWs. An observing system able to quantify the relative contributions of these two processes to the seasonally varying equatorial asymmetry of background circulation would require fine meridional and temporal sampling.

Peterson, T.C., and M.O. Baringer, Editors. State of the climate in 2008. Bulletin of the American Meteorological Society, 90(8):S1-S196 (2009).

No abstract.

Peterson, T.C., and M.O. Baringer. Introduction. In State of the Climate in 2008, T.C. Peterson and M.O. Baringer (eds.). Bulletin of the American Meteorological Society, 90(8):S13-S15 (2009).

No abstract.

Pierrot, D., C. Neil, K. Sullivan, R. Castle, R. Wanninkhof, H. Lueger, T. Johannessen, A. Olsen, R.A. Feely, and C.E. Cosca. Recommendations for autonomous underway pCO₂ measuring systems and data reduction routines. Deep-Sea Research, Part II, 56(8-10):512-522 (2009).

In order to facilitate the collection of high quality and uniform surface water pCO₂ data, an underway pCO₂ instrument has been designed based on community input and is now commercially available. Along with instrumentation, agreements were reached on data reduction and quality control that can be easily applied to data from these systems by using custom-made freeware. This new automated underway pCO₂ measuring system is designed to be accurate to within 0.1 µatm for atmospheric pCO₂ measurements and to within 2 µatm for seawater pCO₂, targeted by the scientific community to constrain the regional air-sea CO₂ fluxes to 0.2 Pg C year^-1. The procedure to properly reduce the underway pCO₂ data and perform the steps necessary for calculation of the fugacity of CO₂ from the measurements is described. This system is now widely used by the scientific community on many different types of ships. Combined with the recommended data-reduction procedures, it will facilitate producing data sets that will significantly decrease the uncertainty currently present in estimates of air-sea CO₂ fluxes.

Powell, M.D., E.W. Uhlhorn, and J.D. Kepert. Estimating maximum surface winds from hurricane reconnaissance measurements. Weather and Forecasting, 24(3):868-883 (2009).

Radial profiles of surface winds measured by the Stepped Frequency Microwave Radiometer (SFMR) are compared to radial profiles of flight-level winds to determine the slant ratio of the maximum surface wind speed to the maximum flight-level wind speed, for flight altitude ranges of 2-4 km. The radius of maximum surface wind is found on average to be 0.875 of the radius of the maximum flight-level wind, and very few cases have a surface wind maximum at greater radius than the flight-level maximum. The mean slant reduction factor is 0.84 with a standard deviation of 0.09 and varies with storm-relative azimuth from a maximum of 0.89 on the left side of the storm to a minimum of 0.79 on the right side. Larger slant reduction factors are found in small storms with large values of inertial stability and small values of relative angular momentum at the flight-level radius of maximum wind, which is consistent with Keperts recent boundary layer theories. The global positioning system (GPS) dropwindsonde-based reduction factors that are assessed using this new dataset have a high bias and substantially larger RMS errors than the new technique. A new regression model for the slant reduction factor based upon SFMR data is presented, and used to make retrospective estimates of maximum surface wind speeds for significant Atlantic basin storms, including Hurricanes Allen (1980), Gilbert (1988), Hugo (1989), Andrew (1992), and Mitch (1998).

Prive, N., Y. Xie, T.W. Schlatter, M. Masutani, R. Atlas, Y. Song, J. Woollen, and S. Koch. Observing system simulation experiments for unmanned aircraft systems: Preliminary efforts. Preprint Volume, 13th Conference on Integrated Observing and Assimilation Systems for the Atmosphere, Oceans, and Land Surface, Phoenix, AZ, January 11-15, 2009. American Meteorological Society, Boston, 4 pp. (2009).

No abstract.

Reasor, P.D., M.D. Eastin, and J.F. Gamache. Rapidly intensifying Hurricane Guillermo (1997), Part I: Low-wavenumber structure and evolution. Monthly Weather Review, 137(2):603-631 (2009).

The structure and evolution of rapidly intensifying Hurricane Guillermo (1997) is examined using airborne Doppler radar observations. In this first part, the low-azimuthal-wavenumber component of the vortex is presented. Guillermo's intensification occurred in an environmental flow with 7-8 m s^-1 of deeplayer vertical shear. As a consequence of the persistent vertical shear forcing of the vortex, convection was observed primarily in the downshear left quadrant of the storm. The greatest intensification during the ~6-h Doppler observation period coincided with the formation and cyclonic rotation of several particularly strong convective bursts through the left-of-shear semicircle of the eyewall. Some of the strongest convective bursts were triggered by azimuthally propagating low-wavenumber vorticity asymmetries. Mesoscale budget analyses of axisymmetric angular momentum and relative vorticity within the eyewall are presented to elucidate the mechanisms contributing to Guillermo's structural evolution during this period. The observations support a developing conceptual model of the rapidly intensifying, vertically sheared hurricane in which shear-forced mesoscale ascent in the downshear eyewall is modulated by internally generated vorticity asymmetries yielding episodes of anomalous intensification.

Rodgers, K.B., R.M. Key, A. Gnanadesikan, J.L. Sarmiento, O. Aumont, L. Bopp, S.C. Doney, J.P. Dunne, D.M. Glover, A. Ishida, M. Ishii, A.R. Jacobson, C.L. Monaco, E. Maier-Reimer, H. Mercier, N. Metzl, F.F. Perez, A.F. Rios, R. Wanninkhof, P. Wetzel, C.D. Winn, and Y. Yamanaka. Using altimetry to help to explain patchy changes in hydrographic carbon measurements. Journal of Geophysical Research, 114(C9):C09013, doi:10.1029/2008JC005183 (2009).

Here we use observations and ocean models to identify mechanisms driving large seasonal to interannual variations in dissolved inorganic carbon (DIC) and dissolved oxygen (O₂) in the upper ocean. We begin with observations linking variations in upper ocean DIC and O₂ inventories with changes in the physical state of the ocean. Models are subsequently used to address the extent to which the relationships derived from short-timescale (6 months to 2 years) repeat measurements are representative of variations over larger spatial and temporal scales. The main new result is that convergence and divergence (column stretching) attributed to baroclinic Rossby waves can make a first-order contribution to DIC and O₂ variability in the upper ocean. This results in a close correspondence between natural variations in DIC and O₂ column inventory variations and sea surface height (SSH) variations over much of the ocean. Oceanic Rossby wave activity is an intrinsic part of the natural variability in the climate system and is elevated even in the absence of significant interannual variability in climate mode indices. The close correspondence between SSH and both DIC and O₂ column inventories for many regions suggests that SSH changes (inferred from satellite altimetry) may prove useful in reducing uncertainty in separating natural and anthropogenic DIC signals (using measurements from Climate Variability and Predictability's CO₂/Repeat Hydrography program).

Roemmich, D., G.C. Johnson, S. Riser, R. Davis, J. Gilson, W.B. Owens, S.L. Garzoli, C. Schmid, and M. Ignaszewski. The Argo Program: Observing the global ocean with profiling floats. Oceanography, 22(2):34-43 (2009).

The Argo Program has created the first global array for observing the subsurface ocean. Argo arose from a compelling scientific need for climate-relevant ocean data; it was made possible by technology development and implemented through international collaboration. The float program and its data management system began with regional arrays in 1999, scaled up to global deployments by 2004, and achieved its target of 3000 active instruments in 2007. U.S. Argo, supported by the National Oceanic and Atmospheric Administration and the Navy through the National Oceanographic Partnership Program, provides half of the floats in the international array, plus leadership in float technology, data management, data quality control, international coordination, and outreach. All Argo data are freely available without restriction, in real time and in research-quality forms. Uses of Argo data range from oceanographic research, climate research, and education, to operational applications in ocean data assimilation and seasonal-to-decadal prediction. Argos value grows as its data accumulate and their applications are better understood. Continuing advances in profiling float and sensor technologies open many exciting possibilities for Argos future, including expanding sampling into high latitudes and the deep ocean, improving near-surface sampling, and adding biogeochemical parameters.

Roemmich, D., M. Belbeoch, H. Freeland, S.L. Garzoli, W.J. Gould, F. Grant, M. Ignaszewski, B. King, B. Klein, P.-Y. Le Traon, K.A. Mork, W.B. Owens, S. Pouliquen, M. Ravichandran, S. Riser, A. Sterl, T. Suga, M.-S. Suk, P. Sutton, V. Thierry, P.J. Velez-Belchi, S. Wijffels, and J. Xu. Argo: The challenge of continuing 10 years of progress. Oceanography, 22(3):46-55 (2009).

In only 10 years, the Argo Program has grown from an idea into a functioning global observing system for the subsurface ocean. More than 3000 Argo floats now cover the world ocean. With these instruments operating on 10-day cycles, the array provides 9000 temperature/salinity/depth profiles every month that are quickly available via the Global Telecommunications System and the Internet. Argo is recognized as a major advance for oceanography, and a success for Argos parent programs, the Global Ocean Data Assimilation Experiment and Climate Variability and Predictability, and for the Global Earth Observation System of Systems. The value of Argo data in ocean data assimilation (ODA) and other applications is being demonstrated, and will grow as the data set is extended in time and as experience in using the data set leads to new applications. The spatial coverage and quality of the Argo data set are improving, with consideration being given to sampling under seasonal ice at higher latitudes, in additional marginal seas, and to greater depths. Argo data products of value in ODA modeling are under development, and Argo data are being tested to confirm their consistency with related satellite and in situ data. Maintenance of the Argo Program for the next decade and longer is needed for a broad range of climate and oceanographic research and for many operational applications in ocean state estimation and prediction.

Rogers, R.F., F.D. Marks, and T. Marchok. Tropical cyclone rainfall. In Encyclopedia of Hydrological Sciences, M.G. Anderson (ed.). John Wiley and Sons, Chicester, UK, doi:10.1002/0470848944.hsa030 (2009).

A brief survey of the relevant research of tropical cyclone (TC) rainfall is presented here. The importance of TC rainfall in global and regional rainfall budgets is discussed, as is its mean characteristics as derived from airborne and satellite observational studies. Discussion is also presented on the physical processes that can modulate TC rainfall distributions, including topography, storm motion, vertical shear, and extratropical transition. Some tools that have been developed to predict and evaluate forecasts of TC rainfall are discussed. Finally, a summary and outlook for the future is presented, including a discussion of opportunities for improving TC rainfall forecasts and conducting research into the role of TC rainfall in intensity and structure changes in TCs.

Rosario, K., E.M. Symonds, C.D. Sinigalliano, J. Stewart, and M. Breitbart. Pepper mild mottle virus as an indicator of fecal pollution. Applied and Environmental Microbiology, 75(22):7261-7267 (2009).

Accurate indicators of fecal pollution are needed in order to minimize public health risks associated with wastewater contamination in recreational waters. However, the bacterial indicators currently used for monitoring water quality do not correlate with the presence of pathogens. Here we demonstrate that the plant pathogen Pepper mild mottle virus (PMMoV) is widespread and abundant in wastewater from the United States, suggesting the utility of this virus as an indicator of human fecal pollution. Quantitative PCR was used to determine the abundance of PMMoV in raw sewage, treated wastewater, seawater exposed to wastewater, and fecal samples and/or intestinal homogenates from a wide variety of animals. PMMoV was present in all wastewater samples at concentrations greater than 1 million copies per milliliter of raw sewage. Despite the ubiquity of PMMoV in human feces, this virus was not detected in the majority of animal fecal samples tested, with the exception of chicken and seagull samples. PMMoV was detected in four out of six seawater samples collected near point sources of secondary treated wastewater off southeastern Florida, where it co-occurred with several other pathogens and indicators of fecal pollution. Since PMMoV was not found in nonpolluted seawater samples and could be detected in surface seawater for approximately 1 week after its initial introduction, the presence of PMMoV in the marine environment reflects a recent contamination event. Together, these data demonstrate that PMMoV is a promising new indicator of fecal pollution in coastal environments.

Sabine, C.L., R.A. Feely, R. Wanninkhof, and T. Takahashi. The global ocean carbon cycle. In State of the Climate in 2008, T.C. Peterson and M.O. Baringer (eds.). Bulletin of the American Meteorological Society, 90(8):S65-S68 (2009).

No abstract.

Schmid, C. National workshop on data analysis in Lagos, Nigeria. Argonautics, 11:7 (2009).

No abstract.

Schmid, C., and S.L. Garzoli. New observations of the spreading and variability of the Antarctic Intermediate Water in the Atlantic. Journal of Marine Research, 67(6):815-843 (2009).

The new and unique Argo data set currently available, in conjunction with other data previously collected, increases our understanding of the spreading of the Antarctic Intermediate Water in the southern and tropical Atlantic Ocean and to verify previous results. The combination of velocity and salinity data collected with Argo floats verified the main patterns of circulation at intermediate (800 to 1100 dbar) depths. Interesting new features in the pathways are found: (1) the existence of a new, third, branch of westward to northwestward flow that is fed by the Benguela Current; (2) two pathways through which the water from the Benguela Current Extension feeds into the Intermediate Western Boundary Current, one turns north at the western boundary while the other one turns north about 10° farther offshore; (3) the core of the South Atlantic Current is located farther north than was thought earlier (at 35 to 38°S instead of south at about 40°S); (4) significant flow of water from the South Atlantic Current to the Antarctic Circumpolar Current occurs east of the Zapiola Eddy (at about 45°S, 35°W); (5) a quite robust eastward current exists at about 20°S; and (6) there are indications, only in the salinity distribution, for southward spreading of Antarctic Intermediate Water from the equator near the eastern boundary. Transport estimates for the 800 to 1100 dbar layer show that the transports of the zonal currents in the subtropical gyre at intermediate depth increase from east to west, and that this trend is nearly linear. The transport of the South Atlantic Current near the western boundary is between 5 and 10 Sv, while it is close to 1 Sv near the eastern boundary of the Atlantic. The transport of the Benguela Current Extension is about 8 Sv near 45°W and only about 1 Sv near 14°E. It is also found that at the bifurcation of the Benguela Current Extension (at 28.5°S) about two thirds of the Antarctic Intermediate Water recirculate in the subtropical gyre, which is a smaller portion than the three quarters reported previously. Zonally integrated transports in the Antarctic Intermediate Water layer show that, as a meridional average, about 3 Sv are transported northward in the 800 to 1100 dbar layer. At 35°S this transport is 2.8 Sv, which amounts to 16% of the total northward transport of the Meridional Overturning Circulation (18 Sv). An analysis of the variability shows that the confluence of the Malvinas Current and the Brazil Current undergo seasonal variations at intermediate depth. The confluence is at its northernmost location (36°S) in July-September. On average the confluence is at 38°S. Both, the variability and the mean location of the confluence at the depth of Antarctic Intermediate Water is similar to what has been observed at the surface.

Schubert, S., D. Gutzler, H. Wang, A. Dai, T. Delworth, C. Deser, K. Findell, R. Fu, W. Higgins, M. Hoerling, B. Kirtman, R. Koster, A. Kumar, D. Legler, D. Lettenmaier, B. Lyon, V. Magana, K. Mo, S. Nigam, P. Pegion, A. Phillips, R. Pulwarty, D. Rind, A. Ruiz-Barradas, J. Schemm, R. Seager, R. Stewart, M. Suarez, J. Syktus, M. Ting, C. Wang, S. Weaver, and N. Zeng. A U.S. CLIVAR project to assess and compare the responses of global climate models to drought-related SST forcing patterns: Overview and results. Journal of Climate, 22(19):5251-5272 (2009).

The U.S. Climate Variability and Predictability (CLIVAR) working group on drought recently initiated a series of global climate model simulations forced with idealized SST anomaly patterns, designed to address a number of uncertainties regarding the impact of SST forcing and the role of landatmosphere feedbacks on regional drought. The runs were carried out with five different atmospheric general circulation models (AGCMs) and one coupled atmosphere-ocean model in which the model was continuously nudged to the imposed SST forcing. This paper provides an overview of the experiments and some initial results focusing on the responses to the leading patterns of annual mean SST variability consisting of a Pacific El Niño-Southern Oscillation (ENSO)-like pattern, a pattern that resembles the Atlantic multidecadal oscillation (AMO), and a global trend pattern. One of the key findings is that all of the AGCMs produce broadly similar (though different in detail) precipitation responses to the Pacific forcing pattern, with a cold Pacific leading to reduced precipitation and a warm Pacific leading to enhanced precipitation over most of the United States. While the response to the Atlantic pattern is less robust, there is general agreement among the models that the largest precipitation response over the United States tends to occur when the two oceans have anomalies of opposite signs. Further highlights of the response over the United States to the Pacific forcing include precipitation signal-to-noise ratios that peak in spring, and surface temperature signal-to-noise ratios that are both lower and show less agreement among the models than those found for the precipitation response. The response to the positive SST trend forcing pattern is an overall surface warming over the worlds land areas, with substantial regional variations that are in part reproduced in runs forced with a globally uniform SST trend forcing. The precipitation response to the trend forcing is weak in all of the models. It is hoped that these early results, as well as those reported in the other contributions to this special issue on drought, will serve to stimulate further analysis of these simulations, as well as suggest new research on the physical mechanisms contributing to hydroclimatic variability and change throughout the world.

Scorzetti, G., L.E. Brand, G.L. Hitchcock, K.S. Rein, C.D. Sinigalliano, and J.W. Fell. Multiple simultaneous detection of harmful algal blooms (HABs) through a high throughput bead array technology, with potential use in phytoplankton community analysis. Harmful Algae, 8(2):196-211 (2009).

As an alternative to traditional, morphology-based methods, molecular techniques can provide detection of multiple species within the HAB community and, more widely, the phytoplankton community in a rapid, accurate and simultaneous qualitative analysis. These methods require detailed knowledge of the molecular diversity within taxa in order to design efficient specific primers and specific probes able to avoid cross-reaction with non-target sequences. Isolates from Florida coastal communities were sequence-analyzed and compared with the GenBank database. Almost 44% of the genotypes obtained did not match any sequence in GenBank, showing the existence of a large and still unexplored biodiversity among taxa. Based on these results and on the GenBank database, we designed 14 species-specific probes and 4 sets of specific primers. Multiple simultaneous detection was achieved with a bead array method based on the use of a flow cytometer and color-coded microspheres, which are conjugated to the developed probes. Following a parallel double PCR amplification, which employed universal primers in a singleplex reaction and a set of species-specific primers in multiplex, detection was performed in a cost effective and highly specific analysis. This multi-format assay, which required less than 4 h to complete from sample collection, can be expanded according to need. Up to 100 different species can be identified simultaneously in a single sample, which allows for additional use of this method in community analyses extended to all phytoplankton species. Our initial field trials, which were based on the 14 species-specific probes, showed the co-existence and dominance of two or more species of Karenia during toxic blooms in Florida waters.

Shen, B.W., W.-K. Tao, J.-D. Chern, R. Atlas, and K. Palaniappan. Scalability improvements in the NASA Goddard multiscale modeling framework for tropical cyclone climate studies. Proceedings, HPC (High Performance Computing) Asia & APAN (Asia-Pacific Advanced Network) 2009 International Conference and Exhibition, March 2-5, 2009, Kaohsiung, Taiwan. National Center for High-Performance Computing, 249-256 (2009).

A current, challenging topic in tropical cyclone (TC) research is how to improve our understanding of TC interannual variability and the impact of climate change on TCs. Paired with the substantial computing power of the NASA Columbia supercomputer, the newly-developed multi-scale modeling framework (MMF) shows potential for the related studies. The MMF consists of two NASA state-of-the-art modeling components, including the finite-volume General Circulation Model (fvGCM) and the Goddard Cumulus Ensemble model (GCE). For TC climate studies, the MMFs computational issues (e.g., limited scalability) need to be addressed. By introducing a meta-grid system, we integrate the GCEs into a meta-global GCE, and apply a two-dimensional domain decomposition in this grid-point space. A prototype parallelism implementation shows very promising scalability, giving a nearly linear speedup as the number of CPUs is increased from 30 to 364. This scalability improvement makes it more feasible to study TC climate. Future work on further model improvement will be also discussed.

Sinigalliano, C.D., J. Winshell, M.A. Guerrero, G. Scorzetti, J.W. Fell, R.W. Eaton, L. Brand, and K.S. Rein. Viable cell sorting of dinoflagellates by multiparametric flow cytometry. Phycologia, 48(4):249-257 (2009).

Electronic cell sorting for isolation and culture of dinoflagellates and other marine eukaryotic phytoplankton was compared to the traditional method of manually picking cells using a micropipette. Trauma to electronically sorted cells was not a limiting factor, as fragile dinoflagellates, such as Karenia brevis (Dinophyceae), survived electronic cell sorting to yield viable cells. The rate of successful isolation of large-scale (> 4 litres) cultures was higher for manual picking than for electronic cell sorting (2% vs 0.5%, respectively). However, manual picking of cells is more labor intensive and time consuming. Most manually isolated cells required repicking, as the cultures were determined not to be unialgal after a single round of isolation; whereas, no cultures obtained in this study from electronic single-cell sorting required resorting. A broad flow cytometric gating logic was employed to enhance species diversity. The percentages of unique genotypes produced by manual picking or electronic cell sorting were similar (57% vs 54%, respectively), and each approach produced a variety of dinoflagellate or raphidophyte genera. Alternatively, a highly restrictive gating logic was successfully used to target K. brevis from a natural bloom sample. Direct electronic single-cell sorting was more successful than utilizing a pre-enrichment sort followed by electronic single-cell sorting. The appropriate recovery medium may enhance the rate of successful isolations. Seventy percent of isolated cells were recovered in a new medium (RE) reported here, which was optimized for axenic dinoflagellate cultures. The greatest limiting factor to the throughput of electronic cell sorting is the need for manual postsort culture maintenance and assessment of the large number of isolated cells. However, when combined with newly developed automated methods for growth screening, electronic single-cell sorting has the potential to accelerate the discovery of new algal strains.

Smith, R.K., M.T. Montgomery, and V.S. Nguyen. Tropical cyclone spin-up revisited. Quarterly Journal of the Royal Meteorological Society, 135(642):1321-1335 (2009).

We present numerical experiments to investigate axisymmetric interpretations of tropical cyclone spin-up in a three-dimensional model. Two mechanisms are identified for the spin-up of the mean tangential circulation. The first involves the convergence of absolute angular momentum above the boundary layer and is a mechanism to spin up the outer circulation, i.e., to increase the vortex size. The second involves the convergence of absolute angular momentum within the boundary layer and is a mechanism to spin up the inner core. It is associated with the development of supergradient wind speeds in the boundary layer. The existence of these two mechanisms provides a plausible physical explanation for certain long-standing observations of typhoons by Weatherford and Gray, which indicate that inner-core changes in the azimuthal-mean tangential wind speed often occur independently from those in the outer core. The unbalanced dynamics in the inner-core region are important in determining the maximum radial and tangential flow speeds that can be attained and are, therefore, important in determining the azimuthal-mean intensity of the vortex. We illustrate the importance of unbalanced flow in the boundary layer with a simple thought experiment. The analyses and interpretations presented are novel and support a recent hypothesis of the boundary layer in the inner-core region.

Takahashi, T., S.C. Sutherland, R. Wanninkhof, C. Sweeney, R.A. Feely, D.W. Chipman, B. Hales, G. Friederich, F. Chavez, C. Sabine, A. Watson, D.C.E. Bakker, U. Schuster, N. Metzl, H. Yoshikawa-Inoue, M. Ishii, T. Midorikawa, Y. Nojiri, A. Kortzinger, T. Steinhoff, M. Hoppema, J. Olafsson, T.S. Arnarson, B. Tilbrook, T. Johannessen, A. Olsen, R. Bellerby, C.S. Wong, B. Delille, N.R. Bates, and H.J.W. de Baar. Climatological mean and decadal change in surface ocean pCO₂ and net sea-air CO₂ flux over the global oceans. Deep-Sea Research, Part II, 56(8-10):554-577 (2009).

A climatological mean distribution for the surface water pCO₂ over the global oceans in non-El Niño conditions has been constructed with spatial resolution of 4° (latitude) x 5° (longitude) for a reference year 2000 based upon about 3 million measurements of surface water pCO₂ obtained from 1970 to 2007. The database used for this study is about 3 times larger than the 0.94 million used for our earlier paper [Takahashi et al., 2002. Global sea-air CO₂ flux based on climatological surface ocean pCO₂, and seasonal biological and temperature effects. Deep-Sea Res. II, 49, 1601-1622]. A time-trend analysis using deseasonalized surface water pCO₂ data in portions of the North Atlantic, North and South Pacific, and Southern Oceans (which cover about 27% of the global ocean areas) indicates that the surface water pCO₂ over these oceanic areas has increased on average at a mean rate of 1.5 µatm y^-1 with basin-specific rates varying between 1.2 ± 0.5 and 2.1 ± 0.4 µatm y^-1. A global ocean database for a single reference year 2000 is assembled using this mean rate for correcting observations made in different years to the reference year. The observations made during El Niño periods in the equatorial Pacific and those made in coastal zones are excluded from the database. Seasonal changes in the surface water pCO₂ and the sea-air pCO₂ difference over four climatic zones in the Atlantic, Pacific, Indian, and Southern Oceans are presented. Over the Southern Ocean seasonal ice zone, the seasonality is complex. Although it cannot be thoroughly documented due to the limited extent of observations, seasonal changes in pCO₂ are approximated by using the data for under-ice waters during austral winter and those for the marginal ice and ice-free zones. The net air-sea CO₂ flux is estimated using the sea-air pCO₂ difference and the air-sea gas transfer rate that is parameterized as a function of (wind speed)² with a scaling factor of 0.26. This is estimated by inverting the bomb ¹⁴C data using Ocean General Circulation models and the 1979-2005 NCEP-DOE AMIP-II Reanalysis (R-2) wind speed data. The equatorial Pacific (14°N-14°S) is the major source for atmospheric CO₂, emitting about +0.48 Pg-C y^-1, and the temperate oceans between 14° and 50° in the both hemispheres are the major sink zones with an uptake flux of -0.70 Pg-C y^-1 for the northern and -1.05 Pg-C y^-1 for the southern zone. The high-latitude North Atlantic, including the Nordic Seas and portion of the Arctic Sea, is the most intense CO₂ sink area on the basis of per unit area, with a mean of -2.5 tons-C month^-1 km^-2. This is due to the combination of the low pCO₂ in seawater and high gas exchange rates. In the ice-free zone of the Southern Ocean (50°-62°S), the mean annual flux is small (-0.06 Pg-C y^-1) because of a cancellation of the summer uptake CO₂ flux with the winter release of CO₂ caused by deepwater upwelling. The annual mean for the contemporary net CO₂ uptake flux over the global oceans is estimated to be -1.6 ± 0.9 Pg-C y^-1, which includes an undersampling correction to the direct estimate of -1.4 ± 0.7 Pg-C y^-1. Taking the pre-industrial steady-state ocean source of 0.4 ± 0.2 Pg-C y^-1 into account, the total ocean uptake flux including the anthropogenic CO₂ is estimated to be -2.0 ± 1.0 Pg-C y^-1 in 2000.

Tao, W.-K., J.-D. Chern, R. Atlas, D. Randall, M. Khairoutdinov, J.-L. Li, D.E. Waliser, A. Hou, X. Lin, C. Peters-Lidard, W. Lau, J. Jiang, and J. Simpson. A multiscale modeling system: Developments, applications, and critical issues. Bulletin of the American Meteorological Society, 9(4):515-534 (2009).

A multiscale modeling framework (MMF), which replaces the conventional cloud parameterizations with a cloud-resolving model (CRM) in each grid column of a GCM, constitutes a new and promising approach for climate modeling. The MMF can provide for global coverage and two-way interactions between the CRMs and their parent GCM. The CRM allows for explicit simulation of cloud processes and their interactions with radiation and surface processes, and the GCM allows for global coverage. A new MMF has been developed that is based on the NASA Goddard Space Flight Center (GSFC) finite-volume GCM (fvGCM) and the Goddard Cumulus Ensemble (GCE) model. This Goddard MMF produces many features that are similar to another MMF that was developed at Colorado State University (CSU), such as an improved surface precipitation pattern, better cloudiness, improved diurnal variability over both oceans and continents, and a stronger propagating MaddenJulian oscillation (MJO) compared to their parent GCMs using traditional cloud parameterizations. Both MMFs also produce a large and positive precipitation bias in the Indian Ocean and western Pacific during the Northern Hemisphere summer. However, there are also notable differences between the two MMFs. For example, the CSU MMF simulates less rainfall over land than its parent GCM. This is why the CSU MMF simulated less overall global rainfall than its parent GCM. The Goddard MMF simulates more global rainfall than its parent GCM because of the high contribution from the oceanic component. A number of critical issues (i.e., the CRM's physical processes and its configuration) involving the Goddard MMF are discussed in this paper.

Telszewski, M., A. Chazottes, U. Schuster, A.J. Watson, C. Moulin, D.C.E. Bakker, M. Gonzalez-Davila, T. Johannessen, A. Kortzinger, H. Lueger, A. Olsen, A. Omar, X.A. Padin, A.F. Rios, T. Steinhoff, M.Santana-Casiano, D.W.R. Wallace, and R. Wanninkhof. Estimating the monthly pCO₂ distribution in the North Atlantic using a self-organizing neural network. Biogeosciences, 6(8):1405-1421 (2009).

Here we present monthly, basin-wide maps of the partial pressure of carbon dioxide (pCO₂) for the North Atlantic on a 1° latitude by 1° longitude grid for years 2004 through 2006 inclusive. The maps have been computed using a neural network technique which reconstructs the non-linear relationships between three biogeochemical parameters and marine pCO₂. A self organizing map (SOM) neural network has been trained using 389,000 triplets of the SeaWiFS-MODIS chlorophyll-a concentration, the NCEP/NCAR reanalysis sea surface temperature, and the FOAM mixed layer depth. The trained SOM was labelled with 137,000 underway pCO₂ measurements collected in situ during 2004, 2005, and 2006 in the North Atlantic, spanning the range of 208 to 437 µatm. The root mean square error (RMSE) of the neural network fit to the data is 11.6 µatm, which equals to just above 3 per cent of an average pCO₂ value in the in situ dataset. The seasonal pCO₂ cycle as well as estimates of the interannual variability in the major biogeochemical provinces are presented and discussed. High resolution combined with basin-wide coverage makes the maps a useful tool for several applications such as the monitoring of basin-wide air-sea CO₂ fluxes or improvement of seasonal and interannual marine CO₂ cycles in future model predictions. The method itself is a valuable alternative to traditional statistical modelling techniques used in geosciences.

Vickery, P.J., F.J. Masters, M.D. Powell, and D. Wadhera. Hurricane hazard modeling: The past, present, and future. Journal of Wind Engineering and Industrial Aerodynamics, 97(7-8):392-405 (2009).

Hurricane hazard modeling has become a commonly used tool for assessing hurricane risk. The type of hurricane risk considered varies with the user and can be an economic risk, as in the case of the insurance and banking industries, a wind exceedance risk, a flood risk, etc. The most common uses for hurricane hazard models today include: (i) Simulation of wind speed and direction for use with wind tunnel test data to estimate wind loads versus return period for design of structural systems and cladding. (ii) Estimation of design wind speeds for use in buildings codes and standards. (iii) Coastal hazard risk modeling (e.g., storm surge elevations and wave heights vs. return period). (iv) Insurance loss estimation (e.g., probable maximum losses, average annual losses). This paper presents an overview of the past and present work in hurricane modeling. The wind model is the key input to each of the examples presented above and is the focus herein. We discuss the evolution and current state of wind field modeling, modeling uncertainties, and possible future directions of the hurricane risk modeling process.

Vickery, P.J., D. Wadhera, M.D. Powell, and Y. Chen. A hurricane boundary layer and wind field model for use in engineering applications. Journal of Applied Meteorology and Climatology, 48(2):381-405 (2009).

This article examines the radial dependence of the height of the maximum wind speed in a hurricane, which is found to lower with increasing inertial stability (which in turn depends on increasing wind speed and decreasing radius) near the eyewall. The leveling off, or limiting value, of the marine drag coefficient in high winds is also examined. The drag coefficient, given similar wind speeds, is smaller for smaller-radii storms; enhanced sea spray by short or breaking waves is speculated as a cause. A fitting technique of dropsonde wind profiles is used to model the shape of the vertical profile of mean horizontal wind speeds in the hurricane boundary layer, using only the magnitude and radius of the gradient wind. The method slightly underestimates the surface winds in small but intense storms, but errors are less than 5% near the surface. The fit is then applied to a slab layer hurricane wind field model, and combined with a boundary layer transition model to estimate surface winds over both marine and land surfaces.

Wang, C., and S.-K Lee. Co-variability of tropical cyclones in the North Atlantic and the eastern North Pacific. Geophysical Research Letters, 36:L24702, doi:10.1029/2009GL041469 (2009).

In the Western Hemisphere, tropical cyclones (TCs) can form and develop in both the tropical North Atlantic (NA) and eastern North Pacific (ENP) Oceans, which are separated by the narrow landmass of Central America. Here it is shown that TC activity in the NA varies out-of-phase with that in the ENP on both interannual and multidecadal timescales. That is, when TC activity in the NA increases (decreases), TC activity in the ENP decreases (increases). Our analyses show that both vertical wind shear and convective instability contribute to the out-of-phase relationship, whereas relative humidity and vorticity variations at the lower troposphere do not seem to cause the relationship. The paper also discusses its association with the Pacific and Atlantic sea surface temperatures. An implication is that seasonal hurricane outlook can be improved by considering the NA and ENP together. It is hoped that this article will stimulate more research regarding TC activity in both the NA and ENP.

Wang, C., and S.-K. Lee. Reply to comment by Joseph J. Barsugli on "Global warming and United States landfalling hurricanes." Geophysical Research Letters, 36(1):L01706, doi:10.1029/2008GL035111 (2009).

No abstract.

Wang, C., F. Kucharski, R. Barimalala, and A. Bracco. Teleconnections of the tropical Atlantic to the tropical Indian and Pacific Oceans: A review of recent findings. Meteorologische Zeitschrift, 18(4):445-454 (2009).

Recent studies found that tropical Atlantic variability may affect the climate in both the tropical Pacific and Indian Ocean basins, possibly modulating the Indian summer monsoon and Pacific ENSO events. A warm tropical Atlantic Ocean forces a Gill-Matsuno-type quadrupole response with a low-level anticyclone located over India that weakens the Indian monsoon circulation, and vice versa for a cold tropical Atlantic Ocean. The tropical Atlantic Ocean can also induce changes in the Indian Ocean sea surface temperatures (SSTs), especially along the coast of Africa and in the western side of the Indian basin. Additionally, it can influence the tropical Pacific Ocean via an atmospheric teleconnection that is associated with the Atlantic Walker circulation. Although the Pacific El Niño does not contemporaneously correlate with the Atlantic Niño, anomalous warming or cooling of the two equatorial oceans can form an inter-basin SST gradient that induces surface zonal wind anomalies over equatorial South America and other regions in both ocean basins. The zonal wind anomalies act as a bridge linking the two ocean basins, and in turn reinforce the inter-basin SST gradient through the atmospheric Walker circulation and oceanic processes. Thus, a positive feedback seems to exist for climate variability of the tropical Pacific-Atlantic Oceans and atmospheric system, in which the inter-basin SST gradient is coupled to the overlying atmospheric wind.

Wang, C., Z. Song, F. Qiao, and S. Dong. What signals are removed and retained by using an anomaly field in climatic research? International Journal of Oceanography, 2009:329754, doi:10.1155/2009/329754, 7 pp. (2009).

Signals in data are often detected by analyzing anomaly field that is calculated by subtracting the mean value over a time length from the data. Here we demonstrate that the anomaly calculation removes signals which satisfy that the ratio between the time length of the mean T and signals' period L is an integer (i.e., T/L = n where n is an integer) and retains other signals if the ratio is not an integer. In climatic and other studies, the time length of the mean is usually chosen as T=12 months from January to December and the mean is called the monthly climatology. Anomaly is calculated by subtracting the monthly climatology from data. This anomaly calculation thus removes the climatic signals with the periods of 12, 6, 4, 3, 2.4, and 2 months which correspond to (12 months)/n with n = 1, 2, 3, 4, 5, and 6, respectively, whereas it retains other signals such as those with the periods of 11, 10, 9, 8, 7, and 5 months. This paper suggests that one should be cautious when an anomaly field is used in research. The conventional notion is that the monthly anomaly calculation removes the annual cycle. However, here we show that the anomaly calculation removes all signals as long as the time length of the mean is an integer multiple of signals period.

Wang, G., Z. Ling, and C. Wang. Influence of tropical cyclones on seasonal ocean circulation in the south China Sea. Journal of Geophysical Research, 114(C10):C10022, doi:10.1029/JC005302 (2009).

The seasonal variability of South China Sea (SCS) ocean circulation influenced by tropical cyclones (TCs) is studied by using satellite QuikSCAT wind data, Sverdrup theory, and a reduced gravity model. TCs can induce a positive (negative) wind stress curl in the northwestern (southeastern) SCS in summer and a positive wind stress curl for the whole SCS in winter. With these wind stress curls induced by TCs, the cyclonic gyre in the northern SCS and the anticyclonic gyre in the southern SCS are intensified in summer. In winter, the cyclonic gyre in the northern SCS is intensified and the gyre in the southern SCS is weakened except in November and December when both gyres are enhanced. The model results show that the dipole structure off central Vietnam in summer is intensified and the eddy off northwestern Luzon Island in winter is weakened by TCs. The present paper shows that TCs can affect both large-scale and mesoscale SCS ocean circulation, suggesting that studies including the effect of TCs are necessary to help improve our understanding of SCS ocean circulation dynamics.

Wang, Z., M.T. Montgomery, and T.J. Dunkerton. A dynamically-based method for forecasting tropical cyclogenesis location in the Atlantic sector using global model products. Geophysical Research Letters, 36(2):L03801, doi:10.1029/2008GL035586 (2009).

A real-time forecast method is developed for prediction of the tropical cyclogenesis location over the Atlantic using global model operational products. The method is based on the marsupial theory for tropical cyclogenesis proposed in a recent observational study. A moisture front is usually found ahead of the precursor wave trough, which separates the relatively dry air outside of the wave pouch (a region of closed circulation) from the relatively moist air inside the wave pouch. The propagation speed of the pouch can be determined by tracking the propagation of this moisture front, and the intersection of the critical surface and the trough axis pinpoints the predicted genesis location. Using the global model operational products, the genesis location can be predicted up to three days in advance with an error less than 200 km, which can provide useful guidance for forecasters and flight planning.

Wanninkhof, R., W.E. Asher, D.T. Ho, C.S. Sweeney, and W.R. McGillis. Advances in quantifying air-sea gas exchange and environmental forcing. Annual Reviews in Marine Science, 1:213-244 (2009).

The past decade has seen a substantial amount of research on air-sea gas exchange and its environmental controls. These studies have significantly advanced the understanding of processes that control gas transfer, led to higher quality field measurements, and improved estimates of the flux of climate-relevant gases between the ocean and atmosphere. This review discusses the fundamental principles of air-sea gas transfer and recent developments in gas transfer theory, parameterizations, and measurement techniques in the context of the exchange of carbon dioxide. However, much of this discussion is applicable to any sparingly soluble, non-reactive gas. We show how the use of global variables of environmental forcing that have recently become available and gas exchange relationships that incorporate the main forcing factors will lead to improved estimates of global and regional air-sea gas fluxes based on better fundamental physical, chemical, and biological foundations.

Watson, A.J., U. Schuster, D.C.E. Bakker, N.R. Bates, A. Corbiere, M. Gonzalez-Davila, T. Friedrich, J. Hauck, C. Heinze, T. Johannessen, A. Kortzinger, N. Metzl, J. Olafsson, A. Olsen, A. Oschlies, X.A. Padin, B. Pfeil, J.M. Santana-Casiano, T. Steinhoff, M. Telszewski, A.F. Rios, D.W.R. Wallace, and R. Wanninkhof. Tracking the variable North Atlantic sink for atmospheric CO₂. Science, 326(5958):1391-1393 (2009).

The oceans are a major sink for atmospheric carbon dioxide (CO₂). Historically, observations have been too sparse to allow accurate tracking of changes in rates of CO₂ uptake over ocean basins, so little is known about how these vary. Here, we show observations indicating substantial variability in the CO₂ uptake by the North Atlantic on time scales of a few years. Further, we use measurements from a coordinated network of instrumented commercial ships to define the annual flux into the North Atlantic, for the year 2005, to a precision of about 10%. This approach offers the prospect of accurately monitoring the changing ocean CO₂ sink for those ocean basins that are well covered by shipping routes.

Wright, C.W., E.J. Walsh, W.B. Krabill, W.A. Shaffer, S.R. Baig, M. Peng, L.J. Pietrafesa, A.W. Garcia, F.D. Marks, P.G. Black, J. Sonntag, and B.D. Beckley. Measuring storm surge with an airborne wide-swath radar altimeter. Journal of Atmospheric and Oceanic Technology, 26(10):2200-2215 (2009).

Over the years, hurricane track forecasts and storm surge models, as well the digital terrain and bathymetry data they depend on, have improved significantly. Strides have also been made in the knowledge of the detailed variation of the surface wind field driving the surge. The area of least improvement has been in obtaining data on the temporal/spatial evolution of the mound of water that the hurricane wind and waves push against the shore to evaluate the performance of the numerical models. Tide gauges in the vicinity of the landfall are frequently destroyed by the surge. Survey crews dispatched after the event provide no temporal information and only indirect indications of the maximum water level over land. The landfall of Hurricane Bonnie on 26 August 1998, with a surge less than 2 m, provided an excellent opportunity to demonstrate the potential benefits of direct airborne measurement of the temporal/spatial evolution of the water level over a large area. Despite a 160-m variation in aircraft altitude, an 11.5-m variation in the elevation of the mean sea surface relative to the ellipsoid over the flight track, and the tidal variation over the 5-h data acquisition interval, a survey-quality global positioning system (GPS) aircraft trajectory allowed the NASA scanning radar altimeter carried by a NOAA hurricane research aircraft to demonstrate that an airborne wide-swath radar altimeter could produce targeted measurements of storm surge that would provide an absolute standard for assessing the accuracy of numerical storm surge models.

Wu, C.-C., J.-H. Chen, S.J. Majumdar, M.S. Peng, C.A. Reynolds, S.D. Aberson, R. Buizza, M. Yamaguchi, S.-G. Chen, T. Nakazawa, and K.-H. Chou. Inter-comparison of targeted observation guidance for tropical cyclones in the northwestern Pacific. Monthly Weather Review, 137(8):2471-2492 (2009).

This study compares six different guidance products for targeted observations over the northwest Pacific Ocean for 84 cases of 2-day forecasts in 2006 and highlights the unique dynamical features affecting the tropical cyclone (TC) tracks in this basin. The six products include three types of guidance based on total-energy singular vectors (TESVs) from different global models, the ensemble transform Kalman filter (ETKF) based on a multimodel ensemble, the deep-layer mean (DLM) wind variance, and the adjoint-derived sensitivity steering vector (ADSSV). The similarities among the six products are evaluated using two objective statistical techniques to show the diversity of the sensitivity regions in large, synoptic-scale domains and in smaller domains local to the TC. It is shown that the three TESVs are relatively similar to one another in both the large and the small domains while the comparisons of the DLM wind variance with other methods show rather low similarities. The ETKF and the ADSSV usually show high similarity because their optimal sensitivity usually lies close to the TC. The ADSSV, relative to the ETKF, reveals more similar sensitivity patterns to those associated with TESVs. Three special cases are also selected to highlight the similarities and differences among the six guidance products and to interpret the dynamical systems affecting the TC motion in the northwestern Pacific. Among the three storms studied, Typhoon Chanchu was associated with the subtropical high, Typhoon Shanshan was associated with the midlatitude trough, and Typhoon Durian was associated with the subtropical jet. The adjoint methods are found to be more capable of capturing the signal of the dynamic system that may affect the TC movement or evolution than are the ensemble methods.

Xu, Y., J. Li, and S. Dong. Ocean circulation from altimetry: Progress and challenges. In Ocean Circulation and El Niño: New Research, J.A. Long and D.S. Wells (ed.). Nova Science Publishers, New York, 71-97 (2009).

The paper provides a review of recent progresses in physical oceanography, such as results on studying ocean circulation and mesoscale ocean dynamics derived from satellite altimetry. Since 1992, satellite altimetry has provided an unprecedented 16 years monitoring of sea level and ocean circulation variations. Continuous measurements from satellites like TOPEX/Poseidon and Jason-1 help us understand and foresee the effects of the change in ocean circulation on climate and on catastrophic climate events such as El Niño and La Niña. Altimeter measurements have improved our understanding of both the dynamics and thermodynamics of western boundary currents by providing a synoptic view of the current systems and their interannual variations, and allowed scientists to quantify eddy-induced salt and heat transport and seasonal and interannual variations in eddy kinetic energy. Altimeter measurements have also been used to map eddies, quantify their amplitudes and diameters, track their trajectories, and examine eddy dynamics and their roles in the ocean processes and climate variability. Recent advances in satellite altimetry, in synergy with other remote sensing techniques, constrain the uncertainty of mechanic energy driving meridional overturning circulation which regulates climate change. Moreover, altimetry has discovered a surprising sea level anomaly propagation speed which challenges the existing linear Rossby wave theory, and revealed the presence of elusive zonal fronts and jets in the ocean. However, challenges still exist in monitoring the ocean variability from satellite altimetry. Satellite altimeters are not able to measure the time-mean geostrophic currents due to the large uncertainty in geoid. This poses challenges for deriving the absolute geostrophic flow in regions where bottom velocities are non-zero since hydrographic estimates of absolute dynamic topography are unable to capture the effects of the bottom. The uncertainties of satellite altimetry measurements have a high geographic variability. The existence of high frequency energetic barotropic motions in the ocean can lead to a large aliasing error in satellite altimetric observations. New evidences show that the combined aliasing from several neighboring and crossing tracks could produce unreal mesoscale signals in altimeter mapped product. Although satellites altimetry has improved our understanding of the climate system dramatically, it is important to keep in mind that problems still remain and new challenges will arise.

Zeng, H., J.Q. Chambers, R.I. Negron-Juarez, G.C. Hurtt, D.B. Baker, and M.D. Powell. Impacts of tropical cyclones on U.S. forest tree mortality and carbon flux from 1851 to 2000. Proceedings of the National Academy of Sciences, 106(19):7888-7892 (2009).

Tropical cyclones cause extensive tree mortality and damage to forested ecosystems. A number of patterns in tropical cyclone frequency and intensity have been identified. There exist, however, few studies on the dynamic impacts of historical tropical cyclones at a continental scale. Here, we synthesized field measurements, satellite image analyses, and empirical models to evaluate forest and carbon cycle impacts for historical tropical cyclones from 1851 to 2000 over the continental U.S. Results demonstrated an average of 97 million trees affected each year over the entire United States, with a 53-Tg annual biomass loss, and an average carbon release of 25 Tg y^-1. Over the period 1980-1990, released CO₂ potentially offset the carbon sink in forest trees by 9-18% over the entire United States. U.S. forests also experienced twice the impact before 1900 than after 1900 because of more active tropical cyclones and a larger extent of forested areas. Forest impacts were primarily located in Gulf Coast areas, particularly southern Texas and Louisiana and south Florida, while significant impacts also occurred in eastern North Carolina. Results serve as an important baseline for evaluating how potential future changes in hurricane frequency and intensity will impact forest tree mortality and carbon balance.

Zhang, H.-M., R.W. Reynolds, R. Lumpkin, R. Molinari, K. Arzayus, M. Johnson, and T.M. Smith. An integrated global observing system for sea surface temperature using satellites and in-situ data: Research to operations. Bulletin of the American Meteorological Society, 90(1):31-38 (2009).

This paper describes the optimal design and its research-to-operation transition of an integrated global observing system of satellites and in situ observations. The integrated observing system is used for climate assessment using sea surface temperature (SST). Satellite observations provide superior samplings while in situ observations provide the ground truth. Observing System Simulation Experiments (OSSEs) were used to objectively design an efficient in situ system to reduce satellite biases to a required accuracy. The system design was peer reviewed and was then transitioned into operations as a U.S. contribution to the international Global Climate Observing System (GCOS). A system performance measure was also formulated and operationally tracked under the Government Performance Results Act (GPRA). Additional OSSEs assisted the planning, programming, budgeting, and execution system at the National Oceanic and Atmospheric Administration (NOAA) to maximize design efficiency. This process of research to operation and decision making enables NOAA to strategically target its observing system investments. The principles of this specific example may have potential applicability to the other components of GCOS.

Zhang, J.A., W.M. Drennan, P.G. Black, and J.R. French. Turbulence structure of the hurricane boundary layer between the outer rain bands. Journal of the Atmospheric Sciences, 66(8):2455-2467 (2009).

As part of the Coupled Boundary Layers Air-Sea Transfer (CBLAST)-Hurricane program, flights were conducted to directly measure turbulent fluxes and turbulence properties in the high-wind boundary layer of hurricanes between the outer rainbands. For the first time, vertical profiles of normalized momentum fluxes, sensible heat and humidity fluxes, and variances of three-dimensional wind velocities and specific humidity are presented for the hurricane boundary layer with surface wind speeds ranging from 20 to 30 m s^-1. The turbulent kinetic energy budget is estimated, indicating that the shear production and dissipation are the major source and sink terms, respectively. The imbalance in the turbulent kinetic energy budget indicates that the unmeasured terms, such as horizontal advection, may be important in hurricane boundary layer structure and dynamics. Finally, the thermodynamic boundary layer height, estimated based on the virtual potential temperature profiles, is roughly half of the boundary layer height estimated from the momentum flux profiles. The latter height where momentum and humidity fluxes tend to vanish is close to that of the inflow layer and also of the maximum in the tangential velocity profiles.

Zhang, J.-Z., C.R. Kelble, C.J. Fischer, and L.D. Moore. Hurricane Katrina induced nutrient runoff from an agricultural area to coastal waters in Biscayne Bay, Florida. Estuarine, Coastal, and Shelf Science, 84(2):209-218 (2009).

Water quality surveys conducted in Biscayne Bay, Florida, indicated enhanced nutrient input coupled with increased runoff as a result of precipitation associated with Hurricane Katrina. Nutrient concentrations before Katrina ranged from 0.06-24.2 mM (mean 3.3 mM) for nitrate and 0.01-0.18 mM (mean 0.1 mM) for soluble reactive phosphate. Five days after Katrina, nitrate concentrations ranged from 0.87-80.0 mM (mean 17.0 mM), with a bay-wide mean increase of 5.2-fold over pre-hurricane levels. Soluble reactive phosphate concentrations ranged from 0.07-0.62 mM (mean 0.2 mM), with a bay-wide mean increase of 2-fold over pre-hurricane levels. The maximum concentrations for both nitrate and soluble reactive phosphate were found at a water quality monitoring station near the mouth of Mowry Canal, which drains an agricultural area in the southern Biscayne Bay watershed near Homestead, Florida. At this station, nitrate and soluble reactive phosphate concentrations increased 7- and 10-fold, respectively. Storm-induced fertilizer runoff from this agricultural area caused a bay-wide increase in nutrient concentrations after Hurricane Katrina. Nutrient concentrations in the bay returned to pre-hurricane levels within three months after Hurricane Katrina, showing the resiliency of the Biscayne Bay ecosystem.

Zipser, E.J., C.H. Twohy, S.-C. Tsay, K.L. Thornhill, S. Tanelli, R. Ross, T.N. Krishnamurti, Q. Ji, G. Jenkins, S. Ismail, N.C. Hsu, R. Hood, G.M. Heymsfield, A. Heymsfield, J. Halverson, H.M. Goodman, R. Ferrare, J.P. Dunion, M. Douglas, R. Cifelli, G. Chen, E.V. Browell, and B. Anderson. The Saharan air layer and the fate of African easterly waves: NASA's AMMA field study of tropical cyclogenesis. Bulletin of the American Meteorological Society, 90(8):1137-1156 (2009).

In 2006, NASA led a field campaign to investigate the factors that control the fate of African easterly waves (AEWs) moving westward into the tropical Atlantic Ocean. Aircraft and surface-based equipment were based on Cape Verdes islands, helping to fill some of the data void between Africa and the Caribbean. Taking advantage of the international African Monsoon Multidisciplinary Analysis (AMMA) program over the continent, the NASA-AMMA (NAMMA) program used enhanced upstream data, whereas NOAA aircraft farther west in the Atlantic studied several of the storms downstream. Seven AEWs were studied during AMMA, with at least two becoming tropical cyclones. Some of the waves that did not develop while being sampled near Cape Verde likely intensified in the central Atlantic instead. NAMMA observations were able to distinguish between the large-scale wave structure and the smaller-scale vorticity maxima that often form within the waves. A special complication of the east Atlantic environment is the Saharan air layer (SAL), which frequently accompanies the AEWs and may introduce dry air and heavy aerosol loading into the convective storm systems in the AEWs. One of the main achievements of NAMMA was the acquisition of a database of remote sensing and in-situ observations of the properties of the SAL, enabling dynamic models and satellite retrieval algorithms to be evaluated against high-quality real data. Ongoing research with this database will help determine how the SAL influences cloud micro-physics and perhaps also tropical cyclogenesis, as well as the more general question of recognizing the properties of small-scale vorticity maxima within tropical waves that are more likely to become tropical cyclones. **2008**

Aberson, S.D. An alternative tropical cyclone intensity forecast verification technique. Weather and Forecasting, 23(6):1304-1310 (2008).

The National Hurricane Center (NHC) does not verify official or model forecasts if those forecasts call for a tropical cyclone to dissipate or if the real tropical cyclone dissipates. A new technique in which these forecasts are included in a contingency table with all other forecasts is presented. Skill scores and probabilities are calculated. Forecast verifications with the currently used technique have shown a slight improvement in intensity forecasts. The new technique, taking into account all forecasts, suggests that the probability of a forecast having a large (>30 kt) error is decreasing, and the likelihood of the error being less than about 10 kt is increasing in time, at all forecast lead times except 12 h when the forecasts are already quite good.

Aberson, S.D. Large forecast degradations due to synoptic surveillance during the 2004 and 2005 hurricane seasons. Monthly Weather Review, 136(8):3138-3150 (2008).

Though operational tropical cyclone synoptic surveillance generally leads to smaller track forecast errors in the National Oceanic and Atmospheric Administration Global Forecasting System (GFS) than would occur otherwise, not every case is improved. Very large GFS forecast degradations due to surveillance are investigated. Small perturbations to model initial conditions may have a large impact locally or downstream in a short time. In these cases, the perturbations are due either to erroneous data assimilated into the models or to issues with the complex data assimilation system itself, and may have caused the forecast degradations. Investigation of forecast and observing system failures can lead to procedural changes that may eliminate some causes of future large forecast errors.

Amornthammarong, N., and J.-Z. Zhang. Shipboard fluorometric flow analyzer for high-resolution underway measurement of ammonium in seawater. Analytical Chemistry, 80(4):1019-1026 (2008).

A shipboard fluorometric flow analyzer has been developed for near-real-time, high-resolution underway measurement of ammonium in seawater. The fluorometric method is based on the reaction of ammonium with o-phthaldialdehyde (OPA) and sulfite. The reagents used in this method have been modified to suit seawater analysis. This method shows no refractive index and salinity effect from seawater samples. The potential interferences in seawater have been studied, and their effects have been reduced. The instrument response is linear over a wide range of ammonium concentration. The limit of detection of 1.1 nM was estimated in laboratory using ammonium standards prepared in distilled water. It should be noted that application of this method to low-level ammonium measurement requires a correction of interference species, such as amino acids. The sample throughput is 3600 h^-1. The system can be used for both freshwater and seawater samples and has been used to monitor the distribution of ammonium in Florida coastal waters around an oceanic wastewater outfall.

Aoyoma, M., J. Barwell-Clarke, S. Becker, M. Blum, E.S. Braga, S.C. Coverly, E. Czobik, I. Dahll�f, M. Dai, G.O. Donnell, C. Engelke, G.-C. Gong, G.-H. Hong, D.J. Hydes, M.-M. Jin, H. Kasai, R. Kerouel, Y. Kiyomono, M. Knockaert, N. Kress, K.A. Krogslund, M. Kumagai, S. Leterme, Y. Li, S. Masuda, T. Miyao, T. Moutin, A. Murata, N. Nagai, G. Nausch, M.K. Ngirchechol, A. Nybakk, H. Ogawa, J. van Ooijen, H. Ota, J.M. Pan, C. Payne, O. Pierre-Duplessix, M. Pujo-Pay, T. Raabe, K. Saito, K. Sato, C. Schmidt, M. Schuett, T.M. Shammon, J. Sun, T. Tanhua, L. White, E.M.S. Woodward, P. Worsfold, P. Yeats, T. Yoshimura, A. You�nou, and J.-Z. Zhang. 2006 inter-laboratory comparison study of a reference material for nutrients in seawater. Technical Report No 58, Meteorological Research Institute, Tsukuba, Japan, 104 pp. (2008).

Autoclaved natural seawater collected in the North Pacific Ocean was used as a reference material for analyzing nutrient concentrations in seawater during an inter-laboratory comparison study conducted in 2006; this study was a follow-up to a similar but smaller study conducted in 2003. Homogeneity of sample #2 was confirmed by the repeatability of the nutrient concentration measurements and those in terms of one sigma of standand deviation are 0.2%, 0.3%, and 0.2% for nitrate, phosphate, and silicate, respectively. Sets of six samples with concentration ranges of 0.1-42.4 µmol kg^-1 for nitrate, 0.0-0.6 µmol kg^-1 for nitrite, 0.0-3.0 µmol kg^-1 for phosphate, and 1.7-156.1 µmol kg^-1 for silicate were analyzed. A set of samples was distributed to each of 55 laboratories around the globe (20 countries), and results were returned by 52 of those laboratories (19 countries). Analytical precisions reported by the participating laboratories for all deteminands were generally lower, by at least 50%, than the consensus standard deviations of the reported concentrations. The consensus standard deviations for sample #2 for all determinands were 5 to 10 times as large as the homogeneities of sample #2 for all determinands. In some laboratories, the non-linearity of the calibration curve was not treated effectively. Our results indicate that variability in the in-house standards of the participating laboratories and the handling of the non-linearity of the calibration curve of the participating laboratories were the primary sources of inter-laboratory discrepancies. The results confirm that a certified reference material for nutrients in seawater and a common method for measuring nutrient concentrations are essential for the improvement of the global comparability of nutrient data in the worlds oceans.

Atlas, R., and G.D. Emmitt. Review of observing system simulation experiments to evaluate the potential impact of lidar winds on numerical weather prediction. ILRC24, Vol. 2 (ISBN 978-0-615-21489-4), 726-729 (2008).

Observing System Simulation Experiments (OSSEs) are an important tool for evaluating the potential impact of proposed new observing systems, as well as for evaluating trade-offs in observing system design, and in developing and assessing improved methodology for assimilating new observations. OSSEs conducted at NASA/GSFC and NOAA/AOML in collaboration with Simpson Weather Associates have indicated significant potential for space-based lidar winds to improve numerical weather prediction. In this paper, we summarize OSSE methodology and earlier OSSE results, and present methodology and results from a "QuickOSSE" designed to assess the potential impact of lidar winds on the predicted track of a specific hurricane.

Atlas, R., and L.P. Riishojgaard. Application of OSSEs to observing system design. In Remote Sensing System Engineering, P.E. Ardanuy and J.J. Puschell (eds.). Proceedings, SPIE, 7087:708707, doi:10.1117/12.795344, 9 pp. (2008).

Observing System Simulation Experiments (OSSEs) are an important tool for evaluating the potential impact of proposed new observing systems, as well as for evaluating trade-offs in observing system design, and in developing and assessing improved methodology for assimilating new observations. Extensive OSSEs have been conducted at NASA/GSFC and NOAA/AOML in collaboration with Simpson Weather Associates and operational data assimilation centers over the last 23 years. These OSSEs determined correctly the quantitative potential for several proposed satellite observing systems to improve weather analysis and prediction prior to their launch, evaluated trade-offs in orbits, coverage and accuracy for space-based wind lidars, and were used in the development of the methodology that led to the first beneficial impacts of satellite surface winds on numerical weather prediction. In this paper, we summarize OSSE methodology and earlier OSSE results, and present methodology and results from recent OSSEs.

Atlas, R., J. Ardizzone, and R.N. Hoffman. Application of satellite surface wind data to ocean wind analysis. In Remote Sensing System Engineering, P.E. Ardanuy and J.J. Puschell (eds.). Proceedings, SPIE, 7087:708707, doi:10.1117/12.795371, 7 pp. (2008).

A new set of cross-calibrated, multi-satellite ocean surface wind data is described. The principal data set covers the global ocean for the period beginning in 1987 with six-hour and 25-km resolution, and is produced by combining all ocean surface wind speed observations from SSM/I, AMSR-E, and TMI, and all ocean surface wind vector observations from QuikSCAT and SeaWinds. An enhanced variational analysis method (VAM) performs quality control and combines these data with available conventional ship and buoy data and ECMWF analyses. The VAM analyses fit the data used very closely and contain small-scale structures not present in operational analyses. Comparisons with withheld WindSat observations are also shown to be very good. These data sets should be extremely useful to atmospheric and oceanic research, and to air-sea interaction studies.

Atlas, R., R.N. Hoffman, J. Ardizzone, M. Leidner, and J.C. Jusem. A new cross-calibrated, multi-satellite ocean surface wind product. Proceedings, International Geoscience and Remote Sensing Symposium, Boston, MA, July 7-11, 2008. IEEE Geoscience and Remote Sensing Society, CD-ROM, 4 pp. (2008).

A new set of cross-calibrated, multi-satellite ocean surface wind data sets is introduced. The principal data set covers the global ocean for the period beginning in 1987 with six-hour, 25-km resolution and is produced by combining all ocean surface wind speed observations from SSM/I, AMSR-E, and TMI, and all ocean surface wind vector observations from QuikSCAT and SeaWinds. An enhanced variational analysis method quality controls and combines these data as well as available conventional ship and buoy data with ECMWF analyses. The analysis fits the data used very closely. Comparisons with withheld WindSat observations are also very good.

Baringer, M.O., and C.S. Meinen. The meridional overturning circulation. In State of the Climate in 2007, D.H. Levinson and J.H. Lawrimore (eds.). Bulletin of the American Meteorological Society, 88(7):S49-S51 (2008).

No abstract.

Bell, M.M., and M.T. Montgomery. Observed structure, evolution, and potential intensity of category 5 Hurricane Isabel (2003) from 12-14 September. Monthly Weather Review, 136(6):2023-2046 (2008).

Unprecedented observations of Hurricane Isabel (2003) at category 5 intensity were collected from 12 to 14 September. This study presents a detailed analysis of the inner-core structure, atmospheric boundary layer, sea surface temperature, and outflow layer of a superintense tropical cyclone using high-resolution in situ flight-level, NCAR GPS dropwindsonde, Doppler radar, and satellite measurements. The analysis of the dropwindsonde and in situ data includes a comprehensive discussion of the uncertainties associated with this observational dataset and provides an estimate of the storm-relative axisymmetric inner-core structure using Barnes objective analysis. An assessment of gradient and thermal wind balance in the inner core is also presented. The axisymmetric data composites presented in this study suggest that Isabel built a reservoir of high moist entropy air by sea-to-air latent heat flux inside the low-level eye that was utilized as an additional energy source to nearly maintain its extreme intensity even after crossing the cool wake of Hurricane Fabian. It is argued here that the combined mean and asymmetric eddy flux of high moist entropy air from the low-level eye into the eyewall represents an additional power source or "turbo boost" to the hurricane heat engine. Recent estimates of the ratio of sea-to-air enthalpy and momentum exchange at high wind speeds are used to suggest that Isabel utilized this extra power to exceed the previously assumed intensity upper bound for the given environmental conditions on all three days. This discrepancy between a priori potential intensity theory and observations may be as high as 35 m s^-1 on 13 September.

Bell, G.D., E. Blake, C.W. Landsea, S.B. Goldenberg, R. Pasch, and T. Kimberlain. Atlantic basin. In State of the Climate in 2007, D.H. Levinson and J.H. Lawrimore (eds.). Bulletin of the American Meteorological Society, 88(7):S68-S71 (2008).

No abstract.

Beron-Vera, F.J., M.J. Olascoaga, and G.J. Goni. Oceanic mesoscale eddies as revealed by Lagrangian coherent structures. Geophysical Research Letters, 35(8):L12603, doi:10.1029/2008GL033957 (2008).

We demonstrate the feasibility of using dynamical systems tools to unambiguously identify mesoscale oceanic eddies from surface ocean currents derived using climatological hydrography and altimetry. Specifically, our analysis is based on extracting Lagrangian coherent structures (LCSs) from finite-time Lyapunov exponent (FTLE) fields. The FTLE fields reveal with unprecedented detail an intricate tangle of LCSs, which are hidden in ocean surface topography maps but sometimes are apparent in ocean color images. These LCSs delineate fluid domains with very different advective properties, and thus their detection provides an objective (i.e., frame-independent) means of identifying eddy boundaries. The importance of considering LCSs in quantifying transport by eddies is highlighted. Such a quantification does not rely on the common assumption-which is shown to be generally not valid-that transport is largely effected by the trapping and subsequent translation of water slugs inside eddies defined as the regions enclosed by sea height (streamfunction) contours within which rotation dominates over strain. LCSs are calculated for the whole globe and compared with satellite-tracked drogue drifter trajectories within a selected region of the South Atlantic.

Bourles, B., R. Lumpkin, M.J. McPhaden, F. Hernandez, P. Nobre, E. Campos, L. Yu, S. Planton, A. Busalacchi, A.D. Moura, J. Servain, and J. Trotte. The PIRATA program: History, accomplishments, and future directions. Bulletin of the American Meteorological Society, 89(8):1111-1125 (2008).

The Pilot Research Moored Array in the tropical Atlantic (PIRATA) was developed as a multinational observation network to improve our knowledge and understanding of ocean-atmosphere variability in the tropical Atlantic. PIRATA was motivated by fundamental scientific issues and by societal needs for improved prediction of climate variability and its impact on the economies of West Africa, northeastern Brazil, the West Indies, and the United States. In this paper the implementation of this network is described, noteworthy accomplishments are highlighted, and the future of PIRATA in the framework of a sustainable tropical Atlantic observing system is discussed. We demonstrate that PIRATA has advanced beyond a Pilot program and, as such, we have redefined the PIRATA acronym to be Prediction and Research Moored Array in the Tropical Atlantic.

Collier, C., R. Ruzicka, K. Banks, L. Barbieri, J. Beal, D. Bingham, J. Bohnsack, S. Brooke, N. Craig, R. Dodge, L. Fisher, N. Gadbois, D. Gilliam, L. Gregg, T. Kellison, V. Kosmynin, B. Lapointe, E. McDevitt, J. Phipps, N. Poulos, J. Proni, P. Quinn, B. Riegl, R.Spieler, J. Walczak, B. Walker, and D. Warrick. The state of coral reef ecosystems of southeast Florida, pp. 131-159. In The State of Coral Reef Ecosystems of the United States and Pacific Freely Associated States: 2008, J.E. Waddell and A.M. Clarke (eds.). NOAA Technical Memorandum, NOAA NCCOS-73, 569 pp. (2008).

No abstract.

DeMaria, M., J.D. Hawkins, J.P. Dunion, and D.K. Smith. Tropical intensity forecasting using a satellite-based total precipitable water product. Extended Abstracts, 28th Conference on Hurricanes and Tropical Meteorology, Orlando, Florida, April 28-May 2, 2008. American Meteorological Society, Boston, 5 pp. (2008).

No abstract.

Dong, S., J. Sprintall, S.T. Gille, and L. Talley. Southern Ocean mixed-layer depth from Argo float profiles. Journal of Geophysical Research, 113(C6):C06013, doi:10.1029/2006JC004051 (2008).

Argo float profiles of temperature, salinity, and pressure are used to derive the mixed-layer depth (MLD) in the Southern Ocean. MLD is determined from individual profiles using both potential density and potential temperature criteria, and a monthly climatology is derived from individual MLDs using an objective mapping method. Quantitative data are available in the auxiliary material. The spatial structures of MLDs are similar in each month, with deep mixed layers within and just north of the Antarctic Circumpolar Current (ACC) in the Pacific and Indian oceans. The deepest mixed layers are found from June to October and are located just north of the ACC where Antarctic Intermediate Water (AAIW) and Subantarctic Mode Water (SAMW) are formed. Examination of individual MLDs indicates that deep mixed layers (MLD > 400 m) from both the density and temperature criteria are concentrated in a narrow surface density band which is within the density range of SAMW. The surface salinity for these deep mixed layers associated with the SAMW formation are slightly fresher compared to historical estimates. Differences in air-sea heat exchanges, wind stress, and wind stress curl in the Pacific and Indian oceans suggest that the mode water formation in each ocean basin may be preconditioned by different processes. Wind mixing and Ekman transport of cold water from the south may assist the SAMW formation in the Indian Ocean. In the eastern Pacific, the formation of mode water is potentially preconditioned by the relative strong cooling and weak stratification from upwelling.

Dunion, J.P., and C.S. Marron. A reexamination of the Jordan mean tropical sounding based on awareness of the Saharan air layer: Results from 2002. Journal of Climate, 21(20):5242-5253 (2008).

The Jordan mean tropical sounding has provided a benchmark for representing the climatology of the tropical North Atlantic and Caribbean Sea since 1958. However, recent studies of the Saharan air layer (SAL) have suggested that the tropical atmosphere in these oceanic regions may contain two distinct soundings (SAL and non-SAL) with differing thermodynamic and kinematic structures and that a single mean sounding like Jordans does not effectively represent these differences. This work addresses this possibility by examining over 750 rawinsondes from the tropical North Atlantic Ocean and Caribbean Sea during the 2002 hurricane season. It was found that a two-peak bimodal moisture distribution (dry SAL and moist non-SAL) exists in this region and that the Jordan sounding does not represent either distribution particularly well. Additionally, SAL soundings exhibited higher values of geopotential height, unique temperature profiles, and stronger winds (with an enhanced easterly component) compared to the moist tropical non-SAL soundings. The results of this work suggest that the Jordan mean tropical sounding may need to be updated to provide a more robust depiction of the thermodynamics and kinematics that exist in the tropical North Atlantic Ocean and Caribbean Sea during the hurricane season.

Dunkerton, T.J., M.T. Montgomery, and Z. Wang. Tropical cyclogenesis in a tropical wave critical layer: Easterly waves. Atmospheric Chemistry and Physics Discussions, 8(3):11149-11292 (2008).

Elipot, S., and R. Lumpkin. Spectral description of oceanic near-surface variability. Geophysical Research Letters, 35(2):L05606, doi:10.1029/2007GL032874 (2008).

This paper provides a spectral description of near-surface oceanic velocity variability on a global scale. Rotary spectra of drifter velocities are estimated in zonal bands of the Indian, Pacific and Atlantic Oceans. The partition of energy between cyclonic and anticyclonic frequencies clearly identifies inertial oscillations at all latitudes. The meridional distribution of near-inertial energy is described in detail. The polarization of super-inertial energy is consistent with internal waves dynamics. Thus, the distribution of super-inertial energy may be a manifestation of freely propagating near-inertial waves on the beta-plane.

Fiechter, J., B.K. Haus, N. Melo, and C.N.K. Mooers. Physical processes impacting passive particle dispersal in the upper Florida Keys. Continental Shelf Research, 28(10-11):1261-1272 (2008).

Physical processes affecting the dispersion of passive particles (e.g., coral larvae, pollutants) in the upper Florida Keys are investigated through in situ observations (acoustic Doppler current profilers and surface drifters) and numerical ocean circulation modeling (horizontal resolution: 800 m, vertical resolution: 0.1-1 m). During the study period in August 2006 (set to coincide with an annual coral spawning event), Lagrangian trajectories in the vicinity of the reef tract indicated that alongshelf advection was mainly poleward and due to the subtidal flow of the Florida Current, while cross-shelf advection was mainly onshore and due to wind-driven currents. Tidal currents resulted in predominantly alongshelf displacements, but did not contribute significantly to net passive particle transport on a weekly timescale. Typical advection distances were of the order of 10 to 50 km for pelagic durations of 1 week, with significant variability linked to geographical location. In contrast, the direction of transport from the offshore reefs remained essentially constant (i.e., potential dispersion pathways were limited). In addition, Lagrangian trajectories and progressive vector diagrams in the vicinity of the reef tract indicate that alongshelf variations in the cross-shelf velocity gradient associated with the FC are relatively weak on an alongshore scale of ca. 50 km. For August 2006, the highest particle concentrations typically occur inshore of the reef tract, thereby suggesting that onshore transport associated with wind-driven currents contributes significantly to the local retention of passive organisms (and other tracers) in the upper Florida Keys. Overall, the results illustrate the necessity of conducting targeted in situ observations and numerical model predictions to quantify the physical processes affecting reef-scale advection, especially in an effort to understand local retention and dispersion mechanisms for larval marine organisms.

Gentry, B., M. McGill, G. Schwemmer, M. Hardesty, A. Brewer, T. Wilkerson, R. Atlas, M. Sirota, S. Lindemann, and F. Hovis. New technologies for direct detection of Doppler lidar: Status of the TWiLiTE airborne molecular Doppler lidar project. ILRC24, Vol. 1 (ISBN 978-0-615-21489-4), 239-243 (2008).

The Tropospheric Wind Lidar Technology Experiment (TWiLiTE) is a three-year program to advance the technology readiness level of the key technologies and subsystems of a molecular direct detection wind lidar system by validating them, at the system level, in an integrated airborne lidar system. The TWiLiTE Doppler lidar system is designed for autonomous operation on NASA high altitude research aircraft such as the WB57 or ER-2. These aircraft are capable of flying well above the mid-latitude tropopause so the downward-looking lidar will measure complete profiles of the horizontal wind field through the lower stratosphere and the entire troposphere. The completed system will profile winds in clear air from the aircraft altitude of 18 km to the surface with 250 m vertical resolution and a velocity precision of < 3 m/s. In this paper, we will describe the new technologies developed as part of the TWiLiTE program and present an update on the status of the airborne lidar system development.

Giammanco, I.M., J.L. Schroeder, M.D. Powell, and D.A. Smith. GPS dropwindsonde observations of tropical cyclone low-level wind maxima. Extended Abstracts, 28th Conference on Hurricanes and Tropical Meteorology, Orlando, Florida, April 28-May 2, 2008. American Meteorological Society, Boston, 8 pp. (2008).

No abstract.

Gledhill, D.K., R. Wanninkhof, F.J. Millero, and M. Eakin. Ocean acidification of the greater Caribbean region, 1996-2006. Journal of Geophysical Research, 113(C10):C10031, doi:10.1029/2007JC004629 (2008).

The global oceans serve as the largest sustained natural sink for increasing atmospheric carbon dioxide (CO₂) concentrations. As this CO₂ is absorbed by seawater, it not only reacts causing a reduction in seawater pH (or acidification) but also decreases the carbonate mineral saturation state (OMEGA), which plays an important role in calcification for many marine organisms. Ocean acidification could affect some of the most fundamental biological and geochemical processes of the sea in coming decades. Observations obtained in situ from Volunteer Observing Ships and multiple geochemical surveys have been extended using satellite remote sensing and modeled environmental parameters to derive estimates of sea-surface alkalinity (A_T) and carbon dioxide partial pressure (pCO_2,sw). Pairing estimates of A_T and pCO_2,sw have permitted characterization of the changes in sea-surface OMEGA, which have transpired over the past decade throughout the Greater Caribbean Region as a consequence of ocean acidification. The results reveal considerable spatial and temporal variability throughout the region. Despite this variability, we observed a strong secular decrease in aragonite saturation state (OMEGA_arg) at a rate of approximately -0.012 � 0.001 OMEGA_arg yr^-1 (r² = 0.97, P < 0.001).

Godin, O.E., and D.R. Palmer (eds.). History of Russian Underwater Acoustics. World Scientific Publishing Company, 1211 pp. (2008).

No abstract.

Goni, G.J. Tropical cyclone heat potential. In State of the Climate in 2007, D.H. Levinson and J.H. Lawrimore (eds.). Bulletin of the American Meteorological Society, 88(7):S43-S45 (2008).

No abstract.

Goodwin, K.D., and R.W. Litaker. Emerging technologies for monitoring recreational waters for bacteria and viruses. In Oceans and Human Health: Risk and Remedies from the Seas, P.J. Walsh, S.L. Smith, W.H. Gerwick, H. Solo-Gabriele, and L.E. Fleming (eds.). Elsevier Science Publishers, New York, 381-404 (2008).

Water quality assessment involves the specific, sensitive, and rapid detection of bacterial indicators and pathogens in water samples, including viable but nonculturable (VBNC) cells. This work evaluates the specificity and sensitivity of a new method which combines a fluorescent in situ hybridization (FISH) approach with a physiological assay (direct viable count DVC) for the direct enumeration, at the single-cell level, of highly diluted viable cells of members of the family Enterobacteriaceae in freshwater and drinking water after membrane filtration. The approach (DVC-FISH) uses a new direct detection device, the laser scanning cytometer (Scan RDI). Combining the DVC-FISH method on a membrane with Scan RDI detection makes it possible to detect as few as one targeted cell in approximately 108 nontargeted cells spread over the membrane. The ability of this new approach to detect and enumerate VBNC enterobacterial cells in freshwater and drinking water distribution systems was investigated and is discussed.

Goodwin, K.D., L. Matragrano, and M.J. LaGier. The possibility of false negative results hampers the ability to elucidate the relationship between fecal indicator bacteria and human pathogens and source tracking markers in beach water and sand. In Marine Pollution: New Research, T.N. Hofer (ed.). Nova Science Publishers, Inc., New York, 255-277 (2008).

Coastal waters can become contaminated with feces through sewage spills, septic tank leaks, animal droppings, and runoff. Beach closures are regulated by testing water samples for fecal-indicating bacteria (FIB), but recent data showing persistence or regrowth of indicators in sand has raised concerns that beach sand may also harbor dangerous bacteria and viruses. Conversely, there is the possibility that regrowth of indicator bacteria in sand and resuspension to the water column may actually produce false positive results. In such a scenario, concentrations of indicator bacteria would not be correlated with human fecal pollution. In this preliminary study, beach sand (wet and dry), water (marine and river), and raw sewage samples were PCR screened for several pathogenic microbes and markers of human fecal pollution. The PCR screen consisted of human specific Bacteroides (HF8 marker), human-specific enterococci (esp gene), Campylobacter jejuni, Escherichia coli 0157:H7, Salmonella spp., Staphylococcus aureus, and adenovirus. The results were compared to concentrations of enterococci, Escherichia coli, and Bacteroides species, as determined by membrane filtration methods. Molecular analysis yielded positive results only in samples of raw sewage, despite relatively high concentrations of FIB in many of the samples. However, estimates of the number of cells delivered to the PCR reaction suggested that few of the samples met the detection limit of the PCR reaction, despite exceedance of EPA single sample guidelines for recreational waters on many of the sample dates. A variety of factors could have contributed to the relatively poor delivery of cells to the PCR reaction, and the analysis indicated a need to improve nucleic acid processing in order to enable better delivery of DNA to downstream molecular methods.

Griffa, A., R. Lumpkin, and M. Veneziani. Cyclonic and anticyclonic motion in the upper ocean. Geophysical Research Letters, 35(1):L01608, doi:10.1029/2007GL032100 (2008).

Upper ocean variability is highly energetic and contributes to key processes such as heat transport and water mass formation. Here, the distribution of ocean surface cyclonic and anticyclonic motion is computed from global drifter observations for scales from large eddies to submesoscale. Two zonal bands of small-scale motion are recovered: a known anticyclonic band at 30�-40� latitude, mostly wind-induced, and an unexpected cyclonic band at 10�-20� latitude. It is suggested that this is due to submesoscale processes related to salinity front instabilities. These results provide a first global view of the upper ocean including these motions.

Halliwell, G.R., L.K. Shay, S.D. Jacob, O.M. Smedstad, and E.W. Uhlhorn. Improving ocean model initialization for coupled tropical cyclone forecast models using GODAE nowcasts. Monthly Weather Review, 136(7):2576-2591 (2008).

To simulate tropical cyclone (TC) intensification, coupled ocean-atmosphere prediction models must realistically reproduce the magnitude and pattern of storm-forced sea surface temperature (SST) cooling. The potential for the ocean to support intensification depends on the thermal energy available to the storm, which in turn depends on both the temperature and thickness of the upper-ocean warm layer. The ocean heat content (OHC) is used as an index of this potential. Large differences in available thermal energy associated with energetic boundary currents and ocean eddies require their accurate initialization in ocean models. Two generations of the experimental U.S. Navy ocean nowcast-forecast system based on the Hybrid Coordinate Ocean Model (HYCOM) are evaluated for this purpose in the northwest Caribbean Sea and Gulf of Mexico prior to Hurricanes Isidore and Lili (2002), Ivan (2004), and Katrina (2005). Evaluations are conducted by comparison to in situ measurements, the Navy's three-dimensional Modular Ocean Data Assimilation System (MODAS) temperature and salinity analyses, microwave satellite SST, and fields of OHC and 26�C isotherm depth derived from satellite altimetry. Both nowcast-forecast systems represent the position of important oceanographic features with reasonable accuracy. Initial fields provided by the first-generation product had a large upper-ocean cold bias because the nowcast was initialized from a biased older-model run. SST response in a free-running Isidore simulation is improved by using initial and boundary fields with reduced cold bias generated from a HYCOM nowcast that relaxed model fields to MODAS analyses. A new climatological initialization procedure used for the second-generation nowcast system tended to reduce the cold bias, but the nowcast still could not adequately reproduce anomalously warm conditions present before all storms within the first few months following nowcast initialization. The initial cold biases in both nowcast products tended to decrease with time. A realistic free-running HYCOM simulation of the ocean response to Ivan illustrates the critical importance of correctly initializing both warm-core rings and cold-core eddies to correctly simulate the magnitude and pattern of SST cooling.

Hendee, J.C., L. Gramer, D.P. Manzello, and M. Jankulak. Integrating near real-time data for coral reef ecological forecasting. Proceedings of the Gulf and Caribbean Fisheries Institute, 59:525-528 (2008).

The National Oceanic and Atmospheric Administration (NOAA) has committed to integrating ocean data from a variety of sources into an Integrated Ocean Observing System, and to work towards operational ecological forecasting as part of its Ecosystem Approach to Management. Consistent with this, NOAA's Coral Reef Conservation Program has committed to integrating coral data from a variety of sources for the specific benefit of coral reef researchers and Marine Protected Area (MPA) managers; and NOAA's Atlantic Oceanographic and Meteorological Laboratory, together with its NOAA and University of Miami partners, are contributing to this goal through their Integrated Coral Observing Network (ICON) project. ICON provides Web-based software to integrate satellite, monitoring station (in situ), and radar data sources in near real-time; and utilizes an inference engine (artificial intelligence software) to provide ecological forecasts using some or all of these data. The capabilities of ICON software are currently being focused upon one area in particular, Molasses Reef in the Florida Keys National Marine Sanctuary, to provide proof-of-concept, and to provide a "discovery prototype" for consideration by the MPA managers assembled at the GCFI conference. Feedback to ICON developers from MPA managers--based upon their own specific management requirements and priorities, and knowledge of the prototype capabilities--is essential to set priorities and enable additional ICON software engineering specifically tailored to MPA managers' needs. Featured in the prototype are several levels of user access: layperson, researcher, site maintainer, MPA manager, and software developer colleague. Depending upon user access, information products can include recent and historical single-source and integrated data output, custom graphics output, and ecological forecasts for coral bleaching, coral spawning, upwelling, pollution impacts and larval drift.

Hendee, J.C., L. Gramer, J.A. Kleypas, D.P. Manzello, M. Jankulak, and C. Langdon. The Integrated Coral Observing Network (ICON): Sensor solutions for sensitive sites. Proceedings, Third International Conference on Intelligent Sensors, Sensor Networks, and Information Processing, Melbourne, Australia, December 3-6, 2007. Institute of Electrical and Electronics Engineers (IEEE), 669-673 (2008).

The National Oceanic and Atmospheric Administration's (NOAA) Integrated Coral Observing Network (ICON) has been operational since 2000 and works closely with most U.S. Government and many international environmental partners involved in coral reef research. The ICON program has pioneered the use of artificial intelligence techniques to assess near real-time data streams from environment sensor networks such as the SEAKEYS Network (Florida Keys), the Australia Institute of Marine Science Weather Network, NOAA's Coral Reef Ecosystem Division network in the Pacific, and its own Integrated Coral Observing Network (ICON) of stations in the Caribbean. Besides its innovative approach to coral monitoring station deployments, the ICON program recently pioneered techniques for the near real-time integration of satellite, in situ, and radar data sources for purposes of ecological forecasting of such events as coral bleaching, coral spawning, upwelling, and other marine behavioral or physical oceanographic events. The ICON program has also ushered in the use of Pulse-Amplitude-Modulating fluorometry to measure near real-time physiological recording of response to environmental stress during coral bleaching, thus providing even better ecological forecasting capabilities through artificial intelligence and data integrative techniques. Herewith, we describe these techniques, along with a report on new coral calcification instrumentation augmenting the ICON Network sensor array.

Hitchcock, G.L., W.S. Arnold, M. Frischer, C.R. Kelble, and R.K. Cowen. Short-term dispersal of an intentionally-released patch of larval Mercenaria Spp. In the Indian River Lagoon, Florida, USA. Bulletin of Marine Science, 82(1):41-57 (2008).

In July 1998 approximately 2.5 x 10⁸ of recently-spawned Mercenaria spp. larvae were intentionally released in the northernmost basin of the Indian River Lagoon, Florida, to characterize the initial dispersion from a point source at time scales of hours to days. Larval densities measured with a quantitative molecular method indicated ambient concentrations were enhanced by 10 larvae L^-1 near surface drifters released with the larvae. Surface distributions from samples collected near the drifters indicate that larval patches developed during the first day. diffusive processes evaluated from dye releases yield apparent diffusivity coefficients that suggest diffusive processes could spread larvae over several km² within 2 d. Our observations suggest that high-resolution methods for mapping larvae are essential to better resolve spatial distribution evolution at time scales of hours to days, and spatial scales of tens to hundreds of meters. This capability could better define the temporal evolution of larval distributions following a mass spawning event.

Huang, X.-L., and J.-Z. Zhang. Kinetic spectrophotometric determination of submicromolar orthophosphate by molybdate reduction. Microchemical Journal, 89(1):58-71 (2008).

A kinetic spectrophotometric procedure was developed for determination of submicromolar orthophosphate based on the reaction in which orthophosphate serves as a catalyst in the reduction of molybdenum, and the initial rate of molybdenum-blue formation (Lambda_max = 780 nm) is proportional to the concentration of orthophosphate in the samples. The detection limit (3 x standard deviation of blank, n = 8) was 6 nM and the linear calibration ranged from 10 to 100 nM (r² = 0.997). The precisions of this method were 3.3% at 10 nM and 5.4% at 50 nM (n = 8), respectively. Similar to other molybdate based methods, silica and arsenate in the samples can interfere with phosphate determination. The responses of silicate and arsenate were about 25% and 7% of that of orthophosphate, respectively, and their interferences were enhanced in the presence of phosphate in the samples due to the synergistic effect of phosphate with arsenate or silicate on the molybdate reagent.

Huang, X.-L., and J.-Z. Zhang. Rate of phosphoantimonylmolybdenum blue complex formation in acidic persulfate digested sample matrix for total dissolved phosphorus determination: Importance of post-digestion pH adjustment. Talanta, 77(1):340-345 (2008).

Acidic persulfate oxidation is one of the most common procedures used to digest dissolved organic phosphorus compounds in water samples for total dissolved phosphorus determination. It has been reported that the rates of phosphoantimonyl-molybdenum blue complex formation were significantly reduced in the digested sample matrix. This study revealed that the intermediate products of persulfate oxidation, not the slight change in pH, cause the slowdown of color formation. This effect can be remedied by adjusting digested samples pH to a near neural to decompose the intermediate products. No disturbing effects of chlorine on the phosphoantimonylmolybdenum blue formation in seawater were observed. It is noted that the modification of mixed reagent recipe cannot provide near neutral pH for the decomposition of the intermediate products of persulfate oxidation. This study provides experimental evidence not only to support the recommendation made in APHA standard methods that the pH of the digested sample must be adjusted to within a narrow range of sample, but also to improve the understanding of role of residue from persulfate decomposition on the subsequent phosphoantimonylmolybdenum blue formation.

Huang, X.-L., Y. Chen, and M. Shenker. Chemical fractionation of phosphorus in stabilized biosolids. Journal of Environmental Quality, 37(5):1949-1958 (2008).

Three chemicals--ferrous sulfate (FeSul), calcium oxide (CaO), and aluminum sulfate (alum)--were applied at different rates to stabilize P in fresh, anaerobically digested biosolids (FBS) obtained from an activated sewage treatment plant. A modified Hedley fractionation procedure was used to assess P forms in these sludge-borne materials and in a biosolids compost (BSC) prepared from the same FBS. Each biosolids material exhibited a unique pattern of P distribution among fractions. The most available P forms, namely: (i) water-soluble P (WSP); (ii) membrane-P; and (iii) NaHCO₃-P, were stabilized by small rates of each of the chemicals; but the P transformation into more stable forms depended on the type of chemical added. The stabilized P forms were enhanced by high rates of CaO and FeSul, but were reduced by high rates of alum. The organic P (P_o) in the first three fractions of the FeSul- and alum-stabilized biosolids was enhanced by the chemical addition, and P_o transformation from NaOH-P_o into NaHCO₃-P_o was found in calcium-stabilized biosolids. A positive relationship was found between NaHCO₃-P_o and the NaHCO₃-extracted organic C in all chemically stabilized biosolids. One-step extraction by NaHCO₃ or NaOH underestimated P extraction compared to the stepwise extraction. The reported results are consistent with solid-state P speciation reported earlier and contribute important information for optimizing biosolids stabilization to reduce P loss after incorporation in soils and for maximizing soil capacity to safely store pre-stabilized biosolids.

Jiang, L.-Q., W.-J. Cai, R. Wanninkhof, Y. Wang, and H. Lueger. Air-sea CO₂ fluxes on the U.S. South Atlantic Bight: Spatial and seasonal variability. Journal of Geophysical Research, 113(C7):C07019, doi:10.1029/2007JC004366 (2008).

The partial pressure of carbon dioxide (pCO₂) in surface seawater on the South Atlantic Bight (SAB) of the United States was measured during six cruises from January 2005 to May 2006. The high-resolution pCO₂ data allow us to create the first maps of the sea surface pCO₂ over the SAB for all seasons. Contrary to an earlier study that was based on limited spatial and seasonal coverage, this study shows that the SAB is a net sink of atmospheric CO₂ on an annual basis (-0.48 � 0.21 mol m^-2 a^-1). The inner shelf is a source of +1.20 � 0.24 mol m^-2 a^-1, while the middle and outer shelves are sinks of -1.23 � 0.19 and -1.37 � 0.21 mol m^-2 a^-1, respectively. Seasonally, the SAB shifts from a sink for atmospheric CO₂ in winter to a source in summer. The annual cycle of sea surface temperature plays a dominant role in controlling the seasonal variation of the pCO₂. Wind speeds are seasonally anti-correlated with the air-sea pCO₂ differences, and this is an important factor in contributing to the net annual air-sea CO₂ exchange. Factors related to the estimates of CO₂ fluxes in the coastal ocean, such as the choice of wind speeds, the correction of gas transfer equations with nonlinearity coefficients, the effect of diel variations of pCO₂, the spatial extrapolation of the pCO₂ to the nearshore area, and the seasonal interpolation, are also discussed.

Johns, W.E., L.M. Beal, M.O. Baringer, J.R. Molina, S.A. Cunningham, T. Kanzow, and D. Rayner. Variability of shallow and deep western boundary currents off the Bahamas during 2004-2005: Results from the 26�N RAPID-MOC array. Journal of Physical Oceanography, 38(3):605-623 (2008).

Data from an array of six moorings deployed east of Abaco, Bahamas, along 26.5�N during March 2004-May 2005 are analyzed. These moorings formed the western boundary array of a transbasin observing system designed to continuously monitor the meridional overturning circulation and meridional heat flux in the subtropical North Atlantic, under the framework of the joint U.K.-U.S. Rapid Climate Change (RAPID)-Meridional Overturning Circulation (MOC) Program. Important features of the western boundary circulation include the southward-flowing deep western boundary current (DWBC) below 1000 m and the northward-flowing "Antilles" Current in the upper 1000 m. Transports in the western boundary layer are estimated from direct current meter observations and from dynamic height moorings that measure the spatially integrated geostrophic flow between moorings. The results of these methods are combined to estimate the time-varying transports in the upper and deep ocean over the width of the western boundary layer to a distance of 500 km offshore of the Bahamas escarpment. The net southward transport of the DWBC across this region, inclusive of northward deep recirculation, is -26.5 Sv (Sv = 10⁶ m³ s^-1), which is divided nearly equally between upper (-13.9 Sv) and lower (-12.6 Sv) North Atlantic Deep Water (NADW). In the top 1000 m, 6.0 Sv flows northward in a thermocline-intensified jet near the western boundary. These transports are found to agree well with historical current meter data in the region collected between 1986 and 1997. Variability in both shallow and deep components of the circulation is large, with transports above 1000 m varying between -15 and +25 Sv and deep transports varying between -60 and +3 Sv. Much of this transport variability, associated with barotropic fluctuations, occurs on relatively short time scales of several days to a few weeks. Upon removal of the barotropic fluctuations, slower baroclinic transport variations are revealed, including a temporary stoppage of the lower NADW transport in the DWBC during November 2004.

Jones, L., P.G. Black, S.S. Chen, R.E. Hood, J.W. Johnson, C.S. Ruf, A. Mims, and C.C. Hennon. Next generation airborne Hurricane Imaging Radiometer (HIRAD): Improved forecast skill with wide field imagery. Tropical Meteorology Special Symposium, New Orleans, LA, January 20-24, 2008. American Meteorological Society, Boston, 8 pp. (2008).

No abstract.

Kanzow, T., J. J.-M. Hirschi, C.S. Meinen, D. Rayner, S.A. Cunningham, J. Marotzke, W.E. Johns, H.L. Bryden, L.M. Beal, and M.O. Baringer. A prototype system of observing the Atlantic meridional overturning circulation: Scientific basis, measurement and risk mitigation strategies, and first results. Journal of Operational Oceanography, 1(1):19-28 (2008).

The Atlantic Meridional Overturning Circulation (MOC) carries up to one quarter of the global northward heat transport in the Subtropical North Atlantic. A system monitoring the strength of the MOC volume transport has been operating since April 2004. The core of this system is an array of moored sensors measuring density, bottom pressure and ocean currents. A strategy to mitigate risks of possible partial failures of the array is presented, relying on backup and complementary measurements. The MOC is decomposed into five components, making use of the continuous moored observations, and of cable measurements across the Straits of Florida, and wind stress data. The components compensate for each other, indicating that the system is working reliably. The year-long average strength of the MOC is 18.7 � 5.6 Sv, with wind-driven and density-inferred transports contributing equally to the variability. Numerical simulations suggest that the surprisingly fast density changes at the western boundary are partially linked to westward propagating planetary waves.

Kelble, C.R., and J.N. Boyer. Southern estuaries hypothesis cluster: Water quality. Comprehensive Everglades Restoration Plan Assessment Team (eds.). Final 2007 System Status Report, 7-5-7.34 (2007).

South Floridas bays and the plants and animals that they support reflect the volume, distribution, and quality of fresh water flowing into these aquatic systems. Past changes to the quality, quantity, timing, and distribution of freshwater flow have degraded water quality and compromised estuarine community structure and function in some areas of the southern estuaries. Current water quality monitoring programs provide adequate spatial and temporal coverage throughout the southern estuaries with the possible exception of the southwest Florida shelf where the temporal variability may not be adequately captured. Chlorophyll a was selected as an indicator of water quality because its biomass is an integrator of many of the water quality factors which may be altered by CERP. There is concern that increased freshwater flow due to CERP activities may result in more frequent, intense, and persistent phytoplankton blooms in the southern estuaries. The baseline conditions indicate that most of the southern estuaries is oligotrophic with median chlorophyll a concentrations of less than or approximately 1 ppb. This baseline data was used as the reference condition to assess the 2006 southern estuaries data, and only the Barnes, Manatee, and Blackwater Sound sub-region was found to have chlorophyll a biomass significantly higher than the baseline. This algal bloom was the result of an increase in total P in this subregion from the combined effects of highway construction and hurricane impacts, including the pre-hurricane freshwater release. This phytoplankton bloom illustrates the sensitivity of the southern estuaries to small increases in nutrient loading, because it took only a small increase in TP (> 10 ppb) to trigger this large phytoplankton bloom, which continues to persist. The ability of our methodologies to adequately detect this decline in water quality due to altered environmental conditions indicates the applicability of this technique to detect changes in water quality as a result of CERP activities. Understanding how CERP affects water quality in the southern estuaries will facilitate adaptively managing and guiding restoration efforts.

Landsea, C.W., D.A. Glenn, W. Bredemeyer, M. Chenoweth, R. Ellis, J.F. Gamache, L. Hufstetler, C.J. Mock, R. Perez, R. Prieto, J. Sanchez-Sesma, D. Thomas, and L. Woolcock. A reanalysis of the 1911-1920 Atlantic hurricane database. Journal of Climate, 21(10):2138-2168 (2008).

A reanalysis of the Atlantic basin tropical storm and hurricane database ("best track") for the period of 1911-20 has been completed. This reassessment of the main archive for tropical cyclones of the North Atlantic Ocean, Caribbean Sea, and Gulf of Mexico was necessary to correct systematic biases and random errors in the data as well as to search for previously unrecognized systems. A methodology for the reanalysis process for revising the track and intensity of tropical cyclone data is provided in detail. The dataset now includes several new tropical cyclones, excludes one system previously considered a tropical storm, makes generally large alterations in the intensity estimates of most tropical cyclones (both toward stronger and weaker intensities), and typically adjusts existing tracks with minor corrections. Average errors in intensity and track values are estimated for both open ocean conditions as well as for landfalling systems. Finally, highlights are given for changes to the more significant hurricanes to impact the United States, Central America, and the Caribbean for this decade.

Lavelle, J.W., and W.C. Thacker. A pretty good sponge: Dealing with open boundaries in limited area ocean models. Ocean Modelling, 20(3):270-292 (2008).

The problem of computing within a limited domain surrounded by open boundaries is discussed within the context of the shallow-water wave equations by comparing three different treatments, all of which surround the domain by absorbing zones intended to prevent reflections of outgoing waves. The first, which has attracted a lot of attention for use in electromagnetic and aeroacoustic applications, is intended to prevent all reflections. However, it has not yet been developed to handle the second important requirement of open boundaries, namely the ability to pass information about external conditions into the domain of interest. The other two treatments, which absorb differences from a specified external solution, allow information to pass through the open boundary in both directions. One, based on the flow relaxation scheme of [Martinsen, E.A., Engedahl, H., 1987. Implementation and testing of a lateral boundary scheme as an open-boundary condition in a barotropic ocean model. Coastal Eng. 11, 603-627] and termed here the "simple sponge," relaxes all fields toward their external counterparts. The other, a simplification and generalization of the perfectly matched layer, referred to here as the "pretty good sponge," avoids absorbing the component of momentum parallel to the open boundary. Comparisons for a case that is dominated by outgoing waves shows the pretty good sponge to perform essentially as well as the perfectly matched layer and better than the simple sponge. In comparisons for a geostrophically balanced eddy passing through open boundaries, the pretty good sponge out-performed the simple sponge when the only external information available was about the advecting flow, but when information about the nature of the eddy in the sponge zones was also available, the simple sponge performed better. For the case of an equatorial soliton passing through the boundary and no information provided about its nature outside the open domain, again the pretty good sponge performed better. Proving useful for situations governed by nonlinear equations forced by external conditions and being easy to implement, the pretty good sponge should be considered for use with existing limited-area ocean models.

Lee, S.-K., and C. Wang. Tropical Atlantic decadal oscillation and its potential impact on the equatorial atmosphere-ocean dynamics: A simple model study. Journal of Physical Oceanography, 38(1):193-212 (2008).

Simple coupled atmosphere-ocean models are used to study the potential influence of the tropical Atlantic Ocean decadal oscillation on the equatorial Atlantic atmosphere-ocean dynamics. Perturbing the model tropical Atlantic at the extratropics (25�-30�) with a decadal frequency, interhemispheric SST dipole mode emerges due to the wind-evaporation-SST feedback. Near the equator, a cross-equatorial oceanic gyre develops owing to the dipole-induced wind stress curl. Once formed, this oceanic gyre transports surface water across the equator from the cold to the warm hemisphere in the western boundary region and from the warm to the cold hemisphere in the Sverdrup interior. Interestingly, this occurs during both the positive and negative phases of the dipole oscillation, thus producing a persistent positive zonal SST gradient along the equator. Bjerknes-type feedback later kicks in to further strengthen the equatorial SST anomaly. Eventually, this feature grows to a quasi-stationary stage sustaining the equatorial westerly wind anomalies, thus also causing the depression (uplift) of the equatorial thermocline in the east (west), a condition similar to the Atlantic Ni�o. The dynamic relationship between the dipole SST oscillation and the equatorial thermocline suggests that a strengthening (weakening) of the dipole mode corresponds to a weakening (strengthening) of the equatorial thermocline slope.

Lee, S.-K., D.B. Enfield, and C. Wang. Why do some El Ni�os have no impact on tropical North Atlantic SST? Geophysical Research Letters, 35(13):L16705, doi:10.1029/2008GL034734 (2008).

Warming of the Tropical North Atlantic (TNA) in boreal spring and early summer (April-June) following El Ni�o peaks in boreal winter is a well-known phenomenon that involves formation of the so-called atmospheric bridge (or teleconnection) from the Pacific. However, the existence of an El Ni�o in boreal winter does not guarantee a warm TNA in the following April-June (AMJ): for sixteen observed El Ni�o events that occurred during 1950-2005, the TNA (AMJ) remained neutral in six of them. A careful examination of the sixteen El Ni�o events leads to a hypothesis that if an El Ni�o ends before April, the TNA remains neutral. Here, we test this working hypothesis by performing multiple sets of ensemble model experiments using the NCAR atmospheric general circulation model coupled to a slab mixed layer ocean model. Analysis of the model experiments indicates that January-March (JFM) are the crucial months for the El Ni�o-induced warming of TNA. Therefore, if an El Ni�o does not continue throughout JFM, the atmospheric bridge connecting the tropical Pacific to the TNA is not persistent enough to force the TNA, thus the TNA remains neutral. Finally, our model experiments indicate even if an El Ni�o continues beyond JFM, the El Ni�o-induced warming of TNA in AMJ can be greatly reduced by Atlantic internal variability, and vice versa.

Lee, T.N., N. Melo, E. Johns, C. Kelble, R.H. Smith, and P.B. Ortner. On water renewal and salinity variability in the northeast subregion of Florida Bay. Bulletin of Marine Science, 82(1):83-105 (2008).

The northeast subregion of Florida Bay receives approximately 75% of the direct freshwater runoff to the bay, most of which is retained within the subregion and has little impact on the dilution of hypersalinity development in adjacent subregions. Using direct measurements of the volume transports through connecting channels and indirectly estimating the total transport to the subregion from mean sea level variability, we show that interior basin water exchanges are weak and controlled by local wind forcing. East-west winds produced seasonally averaged throughflows of 33 and 78 m³ s^-1 during the El Ni�o-influenced wet and dry seasons of 2002 and 2003, respectively, and resulted in a one year residence time for the northeast sub-region. The long residence time of the interior waters is due to the confining nature of the shallow banks and mangrove borders that surround the northeast subregion, as well as the lack of significant tidal exchange. Weak interbasin exchange results in the trapping of freshwater discharge from the Everglades within the northeast subregion. Development of hypersalinity within the north-central subregion of the bay has been associated with seagrass die-off and algal blooms that can cause water quality reduction in south Florida's coastal waters, including the Florida Keys reef tract. To reduce the development of hypersalinity within this region of the bay it will be necessary to divert a portion of the Everglades flow away from the northeast basin and into Whipray Basin during the dry season. Seasonal water balance estimates made for the northeast subregion and previous estimates from the north-central region indicate that groundwater inflows to Florida Bay are negligible and probably not a factor in water quality considerations.

Leidner, S.M., J. Ardizzone, J. Terry, E. Brin, and R. Atlas. Impact of satellite-derived ocean winds on hurricane forecasting at global and regional scales. 12th Symposium on Integrated Observing and Assimilation Systems for the Atmosphere, Oceans, and Land Surface (IOAS-AOLS), New Orleans, LA, January 20-24, 2008. American Meteorological Society, Boston, 5 pp. (2008).

No abstract.

Levine, N.M., S.C. Doney, R. Wanninkhof, K. Lindsay, and I.Y. Fung. Impact of ocean carbon system variability on the detection of temporal increases in anthropogenic CO₂.Journal of Geophysical Research, 113(C3):C03019, doi:10.1029/2007JC004153 (2008).

Estimates of temporal trends in oceanic anthropogenic carbon dioxide (CO₂) rely on the ability of empirical methods to remove the large natural variability of the ocean carbon system. A coupled carbon-climate model is used to evaluate these empirical methods. Both the DELTA-C* and multiple linear regression (MLR) techniques reproduce the predicted increase in dissolved inorganic carbon for the majority of the ocean and have similar average percent errors for decadal differences (24.1% and 25.5%, respectively). However, this study identifies several regions where these methods may introduce errors. Of particular note are mode and deep water formation regions, where changes in air-sea disequilibrium and structure in the MLR residuals introduce errors. These results have significant implications for decadal repeat hydrography programs, indicating the need for subannual sampling in certain regions of the oceans in order to better constrain the natural variability in the system and to robustly estimate the intrusion of anthropogenic CO₂.

Li, Q.P., D.A. Hansell, and J.-Z. Zhang. Underway monitoring of nanomolar nitrate plus nitrite and phosphate in oligotrophic seawater. Limnology and Oceanography: Methods, 6:319-326 (2008).

To study nutrient dynamics and cycling in oligotrophic open ocean environments, continuous measurements of nanomolar nitrate, nitrite, and phosphate are valuable. However, such studies are usually impeded by the detection limits of conventional nutrient-sensors and analyzers. Here, we developed a shipboard deployable underway system for simultaneously monitoring nitrate plus nitrite and phosphate at nanomolar concentrations by the coupling of an optimized flow injection analytical system with two long-path liquid waveguide capillary cells (LWCC). The detection limits are ~2 nM for nitrate plus nitrite and ~1.5 nM for phosphate, respectively. Results from realtime surveys of waters over the west Florida continental shelf and the oligotrophic Sargasso Sea are presented. This system has also been successfully used to analyze more than 1000 discrete seawater samples manually during two cruises in the North Atlantic.

Lorsolo, S., J.L. Schroeder, P.P. Dodge, and F.D. Marks. An observational study of hurricane boundary layer small-scale coherent structures. Monthly Weather Review, 136(8):2871-2893 (2008).

Data with high temporal and spatial resolution from Hurricanes Isabel (2003) and Frances (2004) were analyzed to provide a detailed study of near-surface linear structures with subkilometer wavelengths of the hurricane boundary layer (HBL). The analysis showed that the features were omnipresent throughout the data collection, displayed a horizontal and vertical coherency, and maintained an average orientation of 7� left of the low-level wind. A unique objective wavelength analysis was conducted, where wavelength was defined as the distance between two wind maxima or minima perpendicular to the features' long axis, and revealed that although wavelengths as large as 1400 m were observed, the majority of the features had wavelengths between 200 and 650 m. The assessed wavelengths differ from those documented in a recent observational study. To evaluate the correlation between the features and the underlying near-surface wind field, time and spectral analyses were completed and ground-relative frequency distributions of the features were retrieved. High-energy regions of the power spectral density (PSD) determined from near-surface data were collocated with the features' ground-relative frequency, illustrating that the features have an influence on the near-surface wind field. The additional energy found in the low-frequency range of the PSDs was previously identified as characteristic of the hurricane surface flow, suggesting that the features are an integral component of the HBL flow.

Lorsolo, S., J. Gamache, F. Marks, P. Dodge, and J.A. Zhang. Characterization of hurricane turbulence using airborne Doppler measurements. Extended Abstracts, 28th Conference on Hurricanes and Tropical Meteorology, Orlando, Florida, April 28-May 2, 2008. American Meteorological Society, Boston, 4 pp. (2008).

No abstract.

Lowag, A., M.L. Black, and M.D. Eastin. External and internal influences on structural and intensity changes of Hurricane Bret (1999), Part I: Atmospheric and oceanic influences. Monthly Weather Review, 136(11):4320-4333 (2008).

Hurricane Bret underwent a rapid intensification (RI) and subsequent weakening between 1200 UTC 21 August and 1200 UTC 22 August 1999 before it made landfall on the Texas coast 12 h later. Its minimum sea level pressure fell 35 hPa from 979 to 944 hPa within 24 h. During this period, aircraft of the National Oceanic and Atmospheric Administration (NOAA) flew several research missions that sampled the environment and inner core of the storm. These datasets are combined with gridded data from the National Centers for Environmental Prediction (NCEP) Global Model and the NCEP-National Center for Atmospheric Research (NCAR) reanalyses to document Brets atmospheric and oceanic environment as well as their relation to the observed structural and intensity changes. Brets RI was linked to movement over a warm ocean eddy and high sea surface temperatures (SSTs) in the Gulf of Mexico coupled with a concurrent decrease in vertical wind shear. SSTs at the beginning of the storms RI were approximately 29�C and steadily increased to 30�C as it moved to the north. The vertical wind shear relaxed to less than 10 kt during this time. Mean values of oceanic heat content (OHC) beneath the storm were about 20% higher at the beginning of the RI period than 6 h prior. The subsequent weakening was linked to the cooling of near-coastal shelf waters (to between 25� and 26�C) by prestorm mixing combined with an increase in vertical wind shear. The available observations suggest no intrusion of dry air into the circulation core contributed to the intensity evolution. Sensitivity studies with the Statistical Hurricane Intensity Prediction Scheme (SHIPS) model were conducted to quantitatively describe the influence of environmental conditions on the intensity forecast. Four different cases with modified vertical wind shear and/or SSTs were studied. Differences between the four cases were relatively small because of the model design, but the greatest intensity changes resulted for much cooler prescribed SSTs. The results of this study underscore the importance of OHC and vertical wind shear as significant factors during RIs; however, internal dynamical processes appear to play a more critical role when a favorable environment is present.

Lozier, S., M.O. Baringer, J. Carton, P. Chang, T. Delworth, S.Hakkinen, W. Johns, K. Kelly, T. Lee, T. Liu, J. Toole, and J. Willis (U.S. CLIVAR AMOC Science Team). Progress report for a JSOST near-term priority assessing meridional overturning circulation variability: Implications for rapid climate change. U.S. CLIVAR Report 2008-1, U.S. CLIVAR Office, Washington, DC, 22 pp. (2008).

No abstract.

Lueger, H., R. Wanninkhof, A. Olsen, J. Trinanes, T. Johannessen, D.W.R. Wallace, and A. Kortzinger. The sea-air CO₂ flux in the North Atlantic estimated from satellite and Argo profiling float data. NOAA Technical Memorandum, OAR AOML-96, 28 pp. (2008).

To improve the spatial and temporal resolution of sea-air carbon dioxide (CO₂) flux estimates in the mid-latitude North Atlantic Ocean (30°N-63°N), empirical relationships were derived between the measured fugacity of CO₂ in surface water (fCO_{2 sw}), sea surface temperature (SST), and the mixed layer depth (MLD). Satellite chlorophyll was unsuccessful as a predictive parameter. The algorithms for fCO_{2 sw} predictions were developed using Advanced Very High Resolution Radiometer (AVHRR) satellite SST and MLD data obtained from Argo floats. The root mean square (RMS) difference between the algorithms and fCO_{2 sw} data was 9-10 µatm with a precision, determined from independent data, of 9-11 µatm. This precision is close to that necessary to constrain the sea-air flux in the mid-latitude North Atlantic Ocean to 0.1 Pg C yr^-1. The algorithms were applied on high-resolution SST and MLD data to yield fCO_{2 sw} proxy data for the entire region. The proxy data served to produce seasonal CO₂ flux maps. In 2002, the mid-latitude North Atlantic was a year-round sink and took up 1.9 mol m^-2 yr^-1.

Lumpkin, R., and G.J. Goni. Surface current observations. In D.H. Levinson and J.H. Lawrimore (eds.). Bulletin of the American Meteorological Society, 88(7):S47-S49 (2008).

No abstract.

Lumpkin, R., K. Speer, and K.P. Koltermann. Transport across 48�N in the North Atlantic Ocean. Journal of Physical Oceanography, 38(4):733-752 (2008).

Transports across 48�N in the Atlantic Ocean are estimated from five repeat World Ocean Circulation Experiment (WOCE) hydrographic lines collected in this region in 1993-2000, from time-varying air-sea heat and freshwater fluxes north of 48�N, and from a synthesis of these two data sources using inverse box model methods. Results from hydrography and air-sea fluxes treated separately are analogous to recently published transport variation studies and demonstrate the sensitivity of the results to either the choice of reference level and reference velocities for thermal wind calculations or the specific flux dataset chosen. In addition, flux-based calculations do not include the effects of subsurface mixing on overturning and transports of specific water masses. The inverse model approach was used to find unknown depth-independent velocities, interior diapycnal fluxes, and adjustments to air-sea fluxes subject to various constraints on the system. Various model choices were made to focus on annually averaged results, as opposed to instantaneous values during the occupation of the hydrographic lines. The results reflect the constraints and choices made in the construction of the model. The inverse model solutions show only marginal, not significantly different temporal changes in the net overturning cell strength and heat transport across 48�N. These small changes are similar to seasonally or annually averaged numerical model simulations of overturning. Significant variability is found for deep transports and air-sea flux quantities in density layers. Put another way, if one ignores the details of layer exchanges, the model can be constrained to produce the same net overturning for each repeat line; however, constraining individual layers to have the same transport for each line fails. Diapycnal fluxes are found to be important in the mean but are relatively constant from one repeat line to the next. Mean air-sea fluxes are modified slightly but are still essentially consistent with either the NCEP data or the National Oceanography Centre, Southampton (NOC) Comprehensive Ocean-Atmosphere Data Set (COADS) within error. Modest reductions in air-sea flux uncertainties would give these constraints a much greater impact. Direct transport estimates over broader regions than the western boundary North Atlantic Current are needed to help resolve circulation structure that is important for variability in net overturning.

Mainelli, M., M. DeMaria, L.K. Shay, and G.J. Goni. Application of oceanic heat content estimation to operational forecasting of recent Atlantic category 5 hurricanes. Weather and Forecasting, 23(1):3-16 (2008).

Research investigating the importance of the subsurface ocean structure on tropical cyclone intensity change has been ongoing for several decades. While the emergence of altimetry-derived sea height observations from satellites dates back to the 1980s, it was difficult and uncertain as to how to utilize these measurements in operations as a result of the limited coverage. As the in situ measurement coverage expanded, it became possible to estimate the upper oceanic heat content (OHC) over most ocean regions. Beginning in 2002, daily OHC analyses have been generated at the National Hurricane Center (NHC). These analyses are used qualitatively for the official NHC intensity forecast, and quantitatively to adjust the Statistical Hurricane Intensity Prediction Scheme (SHIPS) forecasts. The primary purpose of this paper is to describe how upper-ocean structure information was transitioned from research to operations, and how it is being used to generate NHC's hurricane intensity forecasts. Examples of the utility of this information for recent category 5 hurricanes (Isabel, Ivan, Emily, Katrina, Rita, and Wilma from the 2003-2005 hurricane seasons) are also presented. Results show that for a large sample of Atlantic storms, the OHC variations have a small but positive impact on the intensity forecasts. However, for intense storms, the effect of the OHC is much more significant, suggestive of its importance on rapid intensification. The OHC input improved the average intensity errors of the SHIPS forecasts by up to 5% for all cases from the category 5 storms, and up to 20% for individual storms, with the maximum improvement for the 72-96-h forecasts. The qualitative use of the OHC information on the NHC intensity forecasts is also described. These results show that knowledge of the upper-ocean thermal structure is fundamental to accurately forecasting intensity changes of tropical cyclones, and that this knowledge is making its way into operations. The statistical results obtained here indicate that the OHC only becomes important when it has values much larger than that required to support a tropical cyclone. This result suggests that the OHC is providing a measure of the upper ocean's influence on the storm and improving the forecast.

Manzello, D.P. Short and long-term ramifications of climate change upon coral reef ecosystems: Case studies across two oceans. Ph.D. thesis, University of Miami, Rosenstiel School of Marine and Atmospheric Science, 82 pp. (2008).

World-wide coral reefs are in a state of decline as a result of many local and regional factors. Recent, global mass mortalities of reef corals due to record warm sea temperatures have led researchers to consider global warming as one of the most significant threats to the persistence of coral reef ecosystems over the next 100 years. It is well established that elevated sea temperatures cause widespread coral bleaching, yet confusion lingers as to what facet of extreme temperatures is most important. Utilizing long-term in situ datasets, nine thermal stress indices were calculated and their effectiveness at segregating bleaching years a posteriori for multiple reefs on the Florida Reef Tract was tested. Simple bleaching thresholds based on deviations above the climatological maximum monthly sea temperature were just as effective at identifying bleaching years as complex thermal stress indices. Near real-time bleaching alerts issued by NOAA's Integrated Coral Observing Network (ICON) are now based upon a running 30-day average SST, such that alerts are only issued when the running 30-day average SST exceeds the estimated bleaching threshold for a particular site. In addition to three widespread, mass-coral bleaching events, the Florida Reef Tract was impacted by three tropical storms and 12 hurricanes from 1997-2005. Sea surface cooling associated with the high frequency of hurricanes that impacted Florida in 2005 likely acted to ameliorate the severity and duration of bleaching. Nonetheless, hurricane-associated cooling is not expected to nullify the proposed effects of climate change on coral reefs. The role of thermal stress in coral bleaching has been extensively studied for eastern tropical Pacific (ETP) coral reefs. However, the ETP presents a unique opportunity as this region has sub-optimal conditions for coral reef development because of upwelling of carbon dioxide-enriched water along the shallow thermocline. This upwelling results in a depressed aragonite saturation state, which is likely an additional factor in the poor reef development throughout the ETP. The highest aragonite saturation states documented in this study occur in the Gulf of Chiriqu�, which corresponds with the greatest reef development of the entire ETP. Seasonal upwelling had a significant effect on the carbonate chemistry of surface waters in Pacific Panama. This regionally-depressed aragonite saturation of the ETP appears to result in corals with a less dense skeleton. Density values of poritid corals from the Galapagos, where aragonite saturation was the lowest documented in this study, were significantly less dense relative to those from Panama and the Great Barrier Reef. The density of non-living pocilloporid framework components were no different across the ETP carbonate saturation gradients. This could be a result of the activity of boring sponges removing the primary carbonate material within the dead coral skeleton, thus lowering density, albeit physical-chemical dissolution cannot be ruled out. These studies provide real-world examples of the ramifications of global climate change upon coral reef ecosystems.

Manzello, D.P., J.A. Kleypas, D.A. Budd, C.M. Eakin, P.W. Glynn, and C. Langdon. Poorly cemented coral reefs of the eastern tropical Pacific: Possible insights into reef development in a high-CO₂ world. Proceeding of the National Academy of Sciences, 105(30):10,450-10,455 (2008).

Ocean acidification describes the progressive, global reduction in seawater pH that is currently underway because of the accelerating oceanic uptake of atmospheric CO₂. Acidification is expected to reduce coral reef calcification and increase reef dissolution. Inorganic cementation in reefs describes the precipitation of CaCO₃ that acts to bind framework components and occlude porosity. Little is known about the effects of ocean acidification on reef cementation and whether changes in cementation rates will affect reef resistance to erosion. Coral reefs of the eastern tropical Pacific (ETP) are poorly developed and subject to rapid bioerosion. Upwelling processes mix cool, subthermocline waters with elevated pCO₂ (the partial pressure of CO₂) and nutrients into the surface layers throughout the ETP. Concerns about ocean acidification have led to the suggestion that this region of naturally low pH waters may serve as a model of coral reef development in a high-CO₂ world. We analyzed seawater chemistry and reef framework samples from multiple reef sites in the ETP and found that a low carbonate saturation state (Omega) and trace abundances of cement are characteristic of these reefs. These low cement abundances may be a factor in the high bioerosion rates previously reported for ETP reefs, although elevated nutrients in upwelled waters may also be limiting cementation and/or stimulating bioerosion. ETP reefs represent a real-world example of coral reef growth in low-Omega waters that provide insights into how the biological-geological interface of coral reef ecosystems will change in a high-CO₂ world.

Marks, F.D., P.G. Black, M.T. Montgomery, and R.W. Burpee. Structure of the eye and eyewall of Hurricane Hugo (1989). Monthly Weather Review, 136(4):1237-1259 (2008).

On 15 September 1989, one of NOAA's WP-3D research aircraft, N42RF [lower aircraft (LA)], penetrated the eyewall of Hurricane Hugo. The aircraft had an engine fail in severe turbulence while passing the radius of maximum wind and before entering the eye at 450-m altitude. After the aircraft returned to controlled flight within the 7-km radius eye, it gained altitude gradually as it orbited in the eye. Observations taken during this period provide an updated model of the inner-core structure of an intense hurricane and suggest that LA penetrated an intense cyclonic vorticity maximum adjacent to the strongest convection in the eyewall [eyewall vorticity maximum (EVM)]. This EVM was distinct from the vortex-scale cyclonic circulation observed to orbit within the eye three times during the 1 h that LA circled in the eye. At the time, Hugo had been deepening rapidly for 12 h. The maximum flight-level tangential wind was 89 m s^-1 at a radius of 12.5 km; however, the primary vortex peak tangential wind, derived from a 100-s filter of the flight-level data, was estimated to be 70 m s^-1, also at 12.5-km radius. The primary vortex tangential wind was in approximate gradient wind balance, was characterized by a peak in angular velocity just inside the radius of maximum wind, and had an annular vorticity structure slightly interior to the angular velocity maximum. The EVM along the aircraft's track was roughly 1 km in diameter with a peak cyclonic vorticity of 1.25 x 10^-1 s^-1. The larger circulation center, with a diameter >15 km, was observed within the eye and exhibited an average orbital period of 19 min. This period is about the same as that of the angular velocity maximum of the axisymmetric mean vortex and is in reasonable agreement with recent theoretical and model predictions of a persistent trochoidal "wobble" of circulation centers in mature hurricane-like vortices. This study is the first with in situ documentation of these vortical entities, which were recently hypothesized to be elements of a lower-tropospheric eye/eyewall mixing mechanism that supports strong storms.

Meinen, C.S. Accuracy in mooring motion temperature corrections. Journal of Atmospheric and Oceanic Technology, 25(12):2293-2303 (2008).

Moored temperature sensors, whether fixed or profiling, routinely need to be corrected to remove the signals associated with the vertical motion of the sensors when the moorings blow over in strong flow events (for profiling sensors the problems occur only at the upper end of the profiling range). Hydrographic data are used to estimate the accuracy with which moored temperature sensors in the Gulf Stream can be corrected for mooring motion aliasing using standard correction techniques, and the implications for other ocean regions are discussed. Comparison with hydrographic data and coincident inverted echo sounder (IES) data from the Synoptic Ocean Prediction Experiment (SYNOP) shows that the errors inherent in mooring motion corrected temperatures during significant pressure deflections are potentially 2-3 times as large as previous estimates based on a smaller dataset of observations in the Kuroshio at approximately the same latitude in the Pacific. For sensors with a nominal level of 400 dbar and a typical root-mean-square pressure deflection of 150 dbar, accuracy limits of up to 0.7�C on the corrected temperatures are applicable. Deeper sensors typically have smaller accuracy bounds. There is a suggestion that the presence of a mode water layer near the nominal depth of the shallowest sensor can result in much higher errors in mooring motion corrected temperature data. The accuracy estimates derived herein should apply not only to moorings deployed in the Gulf Stream but also to all currents that exhibit similar velocity amplitudes and thermal gradients such as the Agulhas or Kuroshio.

Meinen, C.S., and M.O. Baringer. Atlantic meridional overturning circulation shows significant changes in early data from international monitoring systems at 26.5�N. U.S. CLIVAR Variations, 6(1):1-3 (2008).

No abstract.

Miller, T.L., R.M. Atlas, P.G. Black, J.L. Case, S.S. Chen, R.E. Hood, J.W. Johnson, J. Jones, C.S. Ruf, and E.W. Uhlhorn. Simulation of the impact of new aircraft and satellite-based ocean surface wind measurements on H*Wind analyses. 12th Symposium on Integrated Observing and Assimilation Systems for the Atmosphere, Oceans, and Land Surface (IOAS-AOLS), New Orleans, LA, January 20-24, 2008. American Meteorological Society, Boston, 6 pp. (2008).

No abstract.

Miller, T.L., R. Atlas, P.G. Black, C.C. Hennon, S.S. Chen, R.E. Hood, J.W. Johnson, L. Jones, C.S. Ruf, and E.W. Uhlhorn. Simulation of the impact of new ocean surface wind measurements on H*Wind analyses. Extended Abstracts, 28th Conference on Hurricanes and Tropical Meteorology, Orlando, Florida, April 28-May 2, 2008. American Meteorological Society, Boston, 7 pp. (2008).

No abstract.

Molinari, R.L., Z. Garraffo, and D. Snowden. Differences between observed and coupled simulation of North Atlantic sea surface currents and temperature. Journal of Geophysical Research, 113(C9):C09011, doi:10.1029/2008JC004848 (2008).

North Atlantic sea surface temperature (SST) distributions derived from observations and a coupled model from NOAAs Geophysical Fluid Dynamics Laboratory, CM2.1, are compared to evaluate the models ability to simulate recent (1900 to the present) oceanic surface characteristics. The North Atlantic focus will limit our analyses to spatial scales less than gyre, scales usually not addressed in previous model-observation comparisons. Identifying model differences from observations at these scales will assist modelers in identifying problems to be considered and remedies to be applied. The properties compared are the mean annual SST, standard deviation, amplitude of the annual and semiannual harmonic, decadal meridional movements of the axis of the Gulf Stream, propagation of SST anomalies along the axis of the Gulf Stream, and 100-year trends in SST records. Because of the dependence of SST on surface currents, observed flow from surface drifters and simulated flow from 15 m fields are also compared. The model simulates the large-scale properties of all the variables compared. However, there are areas of differences in some variables that can be related to inadequacies in the simulated current fields. For example, the model Gulf Stream (GS) axis after separation from the western boundary is located some 100 km north of the observed axis, which contributes to an area of warmer simulated SSTs. The absence of a slope current in the same region that advects colder water from the Labrador Sea in the observations also contributes to this area of higher model SSTs. The model North Atlantic Current (NAC) is located to the east of the observed NAC contributing to a large area of SST discrepancy. The patterns of the amplitude of the annual harmonic are similar with maximum amplitude off the east coast of northern North America. The semiannual harmonic exhibits relatively large amplitudes (>1�C) north of about 55�N, a signal not found in the observations. In both the model and observations, a region of increased standard deviations encompasses the GS and NAC. The model simulates north-south migrations of the GS core but at a longer period (20 years) than observed. The model does not simulate the SST anomalies that propagate along the observed GS and NAC. The model captures both the spatial and temporal characteristics of the Atlantic Multidecadal Oscillation. Both model and observations exhibit a dipole in trends, with positive trends in the subtropical Atlantic and negative trends in the subpolar gyre. The modeled region of negative trends is limited to the western subpolar Atlantic. The observed trends extend farther to the east.

Moore, R.W., M.T. Montgomery, and H.C. Davies. The integral role of a diabatic Rossby vortex in a heavy snowfall event. Monthly Weather Review, 136(6):1878-1897 (2008).

On 24-25 February 2005, a significant east coast cyclone deposited from 4 to nearly 12 in. (~10-30 cm) of snow on parts of the northeastern United States. The heaviest snowfall and most rapid deepening of the cyclone coincided with the favorable positioning of an upper-level, short-wave trough immediately upstream of a preexisting surface cyclone. The surface cyclone in question formed approximately 15 h before the heaviest snowfall along a coastal front in a region of frontogenesis and heavy precipitation. The incipient surface cyclone subsequently intensified as it moved to the northeast, consistently generating the strongest convection to the east-northeast of the low-level circulation center. The use of potential vorticity (PV) inversion techniques and a suite of mesoscale model simulations illustrates that the early intensification of the incipient surface cyclone was primarily driven by diabatic effects and was not critically dependent on the upper-level wave. These facts, taken in conjunction with the observed structure, energetics, and Lagrangian evolution of the incipient surface disturbance, identify it as a diabatic Rossby vortex (DRV). The antecedent surface vorticity spinup associated with the DRV phase of development is found to be integral to the subsequent rapid growth. The qualitative similarity with a number of observed cases of explosive cyclogenesis leaves open the possibility that a DRV-like feature comprises the preexisting positive low-level PV anomaly in a number of cyclogenetic events that exhibit a two-stage evolution.

Munoz, E., and R. Czujko. AMS membership survey results: Profile of AMS membership residing outside the United States of America. Bulletin of the American Meteorological Society, 89(6):900-904 (2008).

No abstract.

Munoz, E., A.J. Busalacchi, S. Nigam, and A. Ruiz-Barradas. Winter and summer structure of the Caribbean low-level jet. Journal of Climate, 21(6):1260-1276 (2008).

The Caribbean region shows maxima in easterly winds greater than 12 m s^-1 at 925 hPa in July and February, herein referred to as the summer and winter Caribbean low-level jet (LLJ), respectively. It is important to understand the controls and influences of the Caribbean LLJ because other LLJs have been observed to be related to precipitation variability. The purpose of this study is to identify the mechanisms of the Caribbean LLJ formation and variability and their association to the regional hydroclimate. Climatological fields are calculated from the North American Regional Reanalysis and the 40-yr ECMWF Re-Analysis from 1979 to 2001. It is observed that the low-level (925 hPa) zonal wind over the Caribbean basin has a semiannual cycle and an interannual variability, with greater standard deviation during boreal summer. The semiannual cycle has peaks in February and July, which are regional amplifications of the large-scale circulation. High mountains to the south of the Caribbean Sea influence the air temperature meridional gradient, providing a baroclinic structure that favors a stronger easterly wind. The boreal summer strengthening of the Caribbean LLJ is associated with subsidence over the subtropical North Atlantic from the May-to-July shift of the ITCZ and the evolution of the Central American monsoon. Additionally, the midsummer minimum of Caribbean precipitation is related to the Caribbean LLJ through greater moisture flux divergence. From May to September the moisture carried by the Caribbean LLJ into the Gulf of Mexico is strongest. The summer interannual variability of the Caribbean LLJ is due to the variability of the meridional pressure gradient across the Caribbean basin, influenced by tropical Pacific variability during summer.

Murillo, S.T. Determination of the circulation center and inner core evolution of Hurricane Danny (1997) using the GBVTD-simplex algorithm. M.S. thesis, University of Hawaii at Manoa, 57 pp. (2008).

The evolution and structure of Hurricane Danny (1997) is examined via a single-Doppler radar tropical cyclone (TC) wind retrieval technique, the ground-based velocity track display (GBVTD) algorithm. The GBVTD technique is applied to 5-hours of data gathered simultaneously by two WSR-88D radars in Mobile, AL (KMOB) and Slidell, LA (KLIX) at ~6 minute intervals. The circulation centers and the primary circulations of Danny derived from these two independent radar observations (~60 volumes from each radar) are used to evaluate the accuracy of the GBVTD algorithm and the GBVTD-simplex center finding algorithm. Other observations, such as dual-Doppler analysis, dropwindsonde, and in-situ measurements from the NOAA WP-3D and the U.S. Air Force Reserve Command WC-130 (AFRC), aircraft provide independent assessments of the TC center and structure. It is found that the GBVTD-simplex derived centers, which used only the maximum mean tangential wind as the sole criterion, were unsatisfactory and unstable. An improved algorithm is proposed to seek time continuity in RMW, maximum mean tangential wind, and the center position in order to reduce the large fluctuations experienced in this study and the results are used to quantify the accuracy of the derived circulation centers. The quality of the GBVTD-derived circulation from these new centers is assessed. Danny's kinematic structure retrieved from KLIX and KMOB data using the improved sets of centers are consistent with the structures retrieved from the dual-Doppler analyses. Danny evolved from a mostly axisymmetric TC into a wave number one asymmetric TC then returned to an axisymmetric TC during this five-hour period.

Murillo, S.T., W.-C. Lee, G.M. Barnes, M.M. Bell, and F.D. Marks. Determination of the circulation center and inner core evolution of Hurricane Danny (1997) using the GBVTD-simplex algorithm. Extended Abstracts, 28th Conference on Hurricanes and Tropical Meteorology, Orlando, Florida, April 28-May 2, 2008. American Meteorological Society, 5 pp. (2008).

No abstract.

Murillo, S.T., R.E. Pandya, R.Y. Chu, J.A. Winkler, R. Czujko, and E.M.C. Cutrim. AMS membership survey results: An overview and longitudinal analysis of the demographics of the American Meteorological Society. Bulletin of the American Meteorological Society, 89(5):727-733 (2008).

The 2005 membership survey is the fifth in a series of surveys that has monitored the composition of the AMS since 1975. The responses of the 2005 survey reveal several interesting changes in the educational level, employment characteristics, and personal status of Society members. The proportion of members with Ph.D. degrees has increased with time to 46% of the regular (nonstudent) and retired members in 2005. Universities/colleges, the federal government, and radio/TV remain the three most important employers of AMS members, although their relative importance has changed with time, with universities/colleges now employing more members than the federal government. Most AMS members continue to report that they became interested in the atmospheric sciences in either elementary school or as undergraduates, although the importance of early (K-6) experiences has increased with time. The age distribution of AMS members in 2005 suggests that the gradual aging of the AMS membership reported earlier (based on the responses to the 1993 and 1999 surveys) is no longer evident. The 2005 survey results also suggest that the percentage of women in the AMS, although still small, has nearly doubled since 1999. However, there has not been comparable progress in increasing the ethnic diversity of the AMS membership. This paper is the first of a series, each focusing on a particular aspect of the survey results.

Musgrave, K.D., C.A. Davis, and M.T. Montgomery. Numerical simulations of the formation of Hurricane Gabrielle (2001). Monthly Weather Review, 136(8):3151-3167 (2008).

This study examines the formation of Hurricane Gabrielle (2001), focusing on whether an initial disturbance and vertical wind shear were favorable for development. This examination is performed by running numerical experiments using the fifth-generation Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model (MM5). Gabrielle is chosen as an interesting case to study since it formed in the subtropics only a few days before making landfall in Florida. Three simulations are run: a control run and two sensitivity experiments. The control run is compared with observations to establish the closeness of the model output to Gabrielle's observed formation. The two sensitivity experiments are designed to test the response of the developing tropical cyclone to alterations in the initial conditions. The first sensitivity experiment removes the initial (or precursor) disturbance, a midtropospheric vortex located over Florida. The second sensitivity experiment reduces the vertical wind shear over the area of formation. The control run produces a system comparable to Gabrielle. The convection in the control run is consistently located downshear of the center of circulation. In the first sensitivity experiment, with the removal of the initial disturbance, no organized system develops. This indicates the importance of the midtropospheric vortex in Gabrielle's formation. The second sensitivity experiment, which reduces the vertical wind shear over the area of Gabrielle's formation, produces a system that can be identified as Gabrielle. This system, however, is weaker than both the control run and the observations of Gabrielle. This study provides direct evidence of a favorable influence of modest vertical wind shear on the formation of a tropical cyclone in this case.

Nguyen, V.S., N., R.K. Smith, and M.T. Montgomery. Tropical cyclone intensification and predictability in three dimensions. Quarterly Journal of the Royal Meteorological Society, 134(632):563-582 (2008).

We present numerical-model experiments to investigate the dynamics of tropical-cyclone amplification and its predictability in three dimensions. For the prototype amplification problem beginning with a weak-tropical-storm-strength vortex, the emergent flow becomes highly asymmetric and dominated by deep convective vortex structures, even though the problem as posed is essentially axisymmetric. The asymmetries that develop are highly sensitive to the boundary-layer moisture distribution. When a small random moisture perturbation is added in the boundary layer at the initial time, the pattern of evolution of the flow asymmetries is changed dramatically, and a non-negligible spread in the local and azimuthally-averaged intensity results. We conclude, first, that the flow on the convective scales exhibits a degree of randomness, and only those asymmetric features that survive in an ensemble average of many realizations can be regarded as robust; and secondly, that there is an intrinsic uncertainty in the prediction of maximum intensity using either maximum-wind or minimum-surface-pressure metrics. There are clear implications for the possibility of deterministic forecasts of the mesoscale structure of tropical cyclones, which may have a major impact on the intensity and on rapid intensity changes. Some other aspects of vortex structure are addressed also, including vortex-size parameters, and sensitivity to the inclusion of different physical processes or higher spatial resolution. We investigate also the analogous problem on a beta-plane, a prototype problem for tropical-cyclone motion. A new perspective on the putative role of the wind--evaporation feedback process for tropical-cyclone intensification is offered also. The results provide new insight into the fluid dynamics of the intensification process in three dimensions, and at the same time suggest limitations of deterministic prediction for the mesoscale structure. Larger-scale characteristics, such as the radius of gale-force winds and beta-gyres, are found to be less variable than their mesoscale counterparts.

Palmer, C.J., T.D. Bonilla, J.A. Bonilla, S. Elmir, K.D. Goodwin, H.M. Solo-Gabriele, and A. Abdelzaher. The future for monitoring. In Oceans and Human Health: Risk and Remedies from the Seas, P.J. Walsh, S.L. Smith, W.H. Gerwick, H. Solo-Gabriele, and L.E. Fleming (eds.). Elsevier Science Publishers, New York, 405-429 (2008).

No abstract.

Park, G.-H., K. Lee, R. Wanninkhof, J.-Z. Zhang, D.A. Hansell, and R.A. Feely. Large, non-Redfieldian drawdown of nutrients and carbon in the extratropical North Atlantic Ocean (46�N): Evidence for dinitrogen fixation? Limnology and Oceanography, 53(5):1697-1704 (2008).

Considerable drawdown of total dissolved inorganic carbon (C_T) and oversaturation of oxygen (O₂) within a cold (15�C) oligotrophic eddy in the extratropical North Atlantic Ocean (46�N, 20.5�W) indicate that, despite the absence of nitrate (NO₃

), the eddy was highly productive. Estimates of net community production using the mass balances of C_T and O₂ were two to five times greater than those obtained using the mass balance of NO₃

. The remineralization rates obtained using the integrated rates of C_T and NO₃

accumulation and O₂ utilization for the upper thermocline waters (35-300-m depth) were in agreement with C_T- and O₂-based net community production over the same period; however, all the estimates exceeded the NO₃

-based net community production by a factor of two to five, pointing to a considerable accumulation of NO₃

in the upper thermocline in excess of changes in the mixed-layer NO₃

inventory. The amount of this excess NO₃

suggests that a considerable fraction of the net community production was not supported by the mixed-layer NO₃

inventory and that an external source of NO₃

must be present. Of the various mechanisms that might explain the inequity between NO₃

drawdown in the surface layer and NO₃

accumulation in the upper thermocline, N₂ fixation is the most viable yet surprising mechanism for producing such excess NO₃

in this oligotrophic eddy. A significant fraction of net community production in oligotrophic extratropical waters could be supported by processes that are not fully explored or to date have been considered to be insignificant.

Persing, J., and M.T. Montgomery. Isolating surface flux influences on simulated hurricane intensity. Extended Abstracts, 28th Conference on Hurricanes and Tropical Meteorology, Orlando, Florida, April 28-May 2, 2008. American Meteorological Society, Boston, 3 pp. (2008).

No abstract.

Powell, M.D., and T.A. Reinhold. Reply. Bulletin of the American Meteorological Society, 89(2):221-223 (2008).

No abstract.

Powell, M.D., and T.A. Reinhold. Reply to Hsu and Blanchards comments on "Tropical cyclone destructive potential by integrated kinetic energy." Bulletin of the American Meteorological Society, 89(10):1577 (2008).

No abstract.

Proni, J.R., S.J. Stamates, T.P. Carsey, J.-Z. Zhang, C.D. Sinigalliano, and K.F. Sullivan. Acoustic methods for water mass delineation in coastal marine ecosystems. Proceedings, Ninth European Conference on Underwater Acoustics (ECUA 2008), Paris, France, June 29-July 4, 2008. European Acoustics Association, Volume 1, 237-242 (2008).

Acoustical methods play an important role in identifying sources of nutrient to coral reef ecosystems in the South Florida coastal waters. Nutrient fluxes into the coastal ocean are associated with distinct water masses such as inlet discharge plumes, wastewater outfall discharge plumes, and up-welling of deep oceanic water. Various nutrient-bearing water masses can be identified by water column acoustic backscatter profiles, obtained via either ship-borne instrumentation or in-situ instrumentation. Such multidimensional images of water masses can be used to optimize the design of chemical and biological sampling efforts. Examples of water mass imaging will be presented as well as the use of such images in the design of water quality sampling programs.

Pu, Z., X. Li, C.S. Velden, S.D. Aberson, and W.T. Liu. The impact of aircraft dropsonde and satellite wind data on numerical simulations of two landfalling tropical storms during Tropical Cloud Systems and Processes Experiment. Weather and Forecasting, 23(1):62-79 (2008).

Dropwindsonde, Geostationary Operational Environmental Satellite-11 (GOES-11) rapid-scan atmospheric motion vectors, and NASA Quick Scatterometer (QuikSCAT) near-surface wind data collected during NASA's Tropical Cloud Systems and Processes (TCSP) field experiment in July 2005 were assimilated into an advanced research version of the Weather Research and Forecasting (WRF) model using its three-dimensional variational data assimilation (3DVAR) system. The impacts of the mesoscale data assimilation on WRF numerical simulation of Tropical Storms Cindy and Gert (2005) near landfall are examined. Sensitivity of the forecasts to the assimilation of each single data type is investigated. Specifically, different 3DVAR strategies with different analysis update cycles and resolutions are compared in order to identify the better methodology for assimilating the data from research aircraft and satellite for tropical cyclone study. The results presented herein indicate the following. (1) Assimilation of dropwindsonde and satellite wind data into the WRF model improves the forecasts of the two tropical storms up to the landfall time. The QuikSCAT wind information is very important for improving the storm track forecast, whereas the dropwindsonde and GOES-11 wind data are also necessary for improved forecasts of intensity and precipitation. (2) Data assimilation also improves the quantitative precipitation forecasts (QPFs) near landfall of the tropical storms. (3) A 1-h rapid-update analysis cycle at high resolution (9 km) provides more accurate tropical cyclone forecasts than a regular 6-h analysis cycle at coarse (27 km) resolution. The high-resolution rapidly updated 3DVAR analysis cycle might be a practical way to assimilate the data collected from tropical cyclone field experiments.

Rogers, R.F., and E.W. Uhlhorn. Observations of the structure and evolution of surface and flight-level wind asymmetries in Hurricane Rita (2005). Geophysical Research Letters, 35(21):L22811, doi:10.1029/2008GL034774 (2008).

Knowledge of the magnitude and distribution of surface winds, including the structure of azimuthal asymmetries in the wind field, are important factors for tropical cyclone forecasting. With its ability to remotely measure surface wind speeds, the stepped frequency microwave radiometer (SFMR) has assumed a prominent role for the operational tropical cyclone forecasting community. An example of this instruments utility is presented here, where concurrent measurements of aircraft flight-level and SFMR surface winds are used to document the wind field evolution over three days in Hurricane Rita (2005). The amplitude and azimuthal location (phase) of the wavenumber-1 asymmetry in the storm-relative winds varied at both levels over time. The peak was found to the right of storm track at both levels on the first day. By the third day, the peak in flight-level storm-relative winds remained to the right of storm track, but it shifted to left of storm track at the surface, resulting in a 60-degree shift between the surface and flight-level and azimuthal variations in the ratio of surface to flight-level winds. The asymmetric differences between the surface and flight-level maximum wind radii also varied, indicating a vortex whose tilt was increasing.

Rule, E. Unmanned aircraft systems for hurricane research. Earth System Monitor, 17(2):7 (2008).

No abstract.

Sabine, C.L., R.A. Feely, R. Wanninkhof, and T. Takahashi. The global ocean carbon cycle. In State of the Climate in 2007, D.H. Levinson and J.H. Lawrimore (eds.). Bulletin of the American Meteorological Society, 88(7):S52-S56 (2008).

No abstract.

Sallee, J.-B., K. Speer, R. Morrow, and R. Lumpkin. An estimate of Lagrangian eddy statistics and diffusion in the mixed layer of the Southern Ocean. Journal of Marine Research, 66(4):441-463 (2008).

A statistical analysis of surface drifter observations is used to compute eddy length and time scales and eddy diffusion in the Southern Ocean. Eddy diffusion values of the order of 10⁴ m² s^-1 are found in the energetic western boundary currents north of the Antarctic Circumpolar Current (ACC) and secondary peaks occur where the ACC negotiates topography. The diffusivity shows an increase from the Antarctic continent to the core of the ACC, then a slight decrease or a stable plateau within the ACC. North of the ACC, diffusivity generally decreases into the interior of ocean basins, except in the western boundary regions where values are maximum. Diffusivity is also calculated from simulated trajectories based on altimetric geostrophic velocities, with and without mean flow, as well as with simulated trajectories based on Ekman currents. Ekman currents at the drogue depth (15 m) have only a small impact, and the geostrophic currents dominate the eddy diffusivity. Complementary statistical analyses confirm these results. The surface drifter cross-stream eddy diffusion is used to test a simple parameterization based on satellite altimetric observations of eddy kinetic energy (EKE). For EKE � 0.015 m² s^-2, kappa = 1.35�EKE L_d m² s^-1, where L_d is the first baroclinic Rossby radius. This parameterization holds in the energetic ACC, consistent with an eddy field in the frozen field regime. Over the broader areas of weaker eddy fields, mixing is fairly uniform and stable at about kappa = 1800 � 1000 m² s^-1.

Sellwood, K.J., S. Majumdar, I. Szunyogh, and B. Mapes. Predicting the influence of observations on medium-range forecasts of atmospheric flow. Quarterly Journal of the Royal Meteorological Society, 134(637):2011-2027 (2008).

In recent years, the Ensemble Transform Kalman Filter (ETKF) has been demonstrated to be useful for identifying a priori dynamically important locations for the placement of supplementary dropwindsonde observations aimed at improving short-range (1-3 day) forecasts of high-impact winter weather. In this paper, the ability of this strategy to predict the influence (or signal) of assimilating observations into the NCEP Global Forecast System for forecasts of 200 hPa wind up to 6 days is evaluated. Using a 50-member ECMWF ensemble, the ETKF was found to exhibit significantly higher skill than a seasonal climatology of the important locations in predicting both (1) the spatial structure of signals within the storm track on a case-by-case basis; and (2) the variance of these signals over a 2-month period, within objectively chosen verification regions on synoptic scales. The verification region was selected by extracting the zonal envelope of the Rossby wave packet associated with the propagating ETKF signal variance. It is recommended that larger verification regions be used for longer lead times, due to the eastward expansion of the wave packet. The capability of the ETKF to predict signal variance out to 6 days was found to be dependent on the flow regime. The ETKF was most capable when the background flow was predominantly zonal, and least capable in instances where the observations were placed upstream of a blocking high over the north-eastern Pacific. Therefore, the ETKF is sometimes (but not always) able to predict when there exists significant potential for a particular group of observations to improve medium-range forecasts.

Serafy, J.E., C.R. Keble, T.R. Capo, S.A. Luthy and P.B. Ortner. Vertical movement rates of captive larval billfishes (Istiophoridae) collected from the Straits of Florida. Florida Scientist, 71(1):23-30 (2008).

Challenges associated with species identification, live collection and laboratory maintenance of billfish larvae have hindered research on their physiology and behavior. In the present study, short-duration neuston net tows in the Straits of Florida yielded 19 live istiophorid billfish larvae, which were immediately placed in a shipboard vertical swimming chamber to measure their vertical movement rates. After swimming trials, larvae were transferred to the laboratory where they were identified to species, classified as to flexion stage and measured for length. Mean vertical swimming speeds of captive larval sailfish (Istiophorus platypterus) and blue marlin (Makaira nigricans) ranged from 1.0 to 7.0 cm s^-1 or 1.6 to 5.6 body lengths s^-1. These rates exceed most larval fish sinking rates reported for other species and are comparable to mean larval "cruising" speeds reported for several temperate freshwater and marine fishes; however, they appear far lower than most swimming speed estimates for reef fish larvae.

Shay, L.K., and E.W. Uhlhorn. Loop Current response to Hurricanes Isidore and Lili. Monthly Weather Review, 136(9):3248-3274 (2008).

Recent hurricane activity over the Gulf of Mexico basin has underscored the importance of the Loop Current (LC) and its deep, warm thermal structure on hurricane intensity. During Hurricanes Isidore and Lili in 2002, research flights were conducted from both National Oceanic and Atmospheric Administration (NOAA) WP-3D aircraft to observe pre-, in- and poststorm ocean conditions using airborne expendable ocean profilers to measure temperature, salinity, and current structure. Atmospheric thermodynamic and wind profiles and remotely sensed surface winds were concurrently acquired as each storm moved over the LC. Observed upper-ocean cooling was about 1�C as Isidore moved across the Yucatan Straits at a speed of 4 m s^-1. Given prestorm ocean heat content (OHC) levels exceeding 100 kJ cm^-2 in the LC (current velocities >1 m s^-1), significant cooling and deepening of the ocean mixed layer (OML) did not occur in the straits. Estimated surface enthalpy flux at Isidores eyewall was 1.8 kW m^-2, where the maximum observed wind was 49 m s^-1. Spatially integrating these surface enthalpy fluxes suggested a maximum surface heat loss of 9.5 kJ cm^-2 at the eyewall. Over the Yucatan Shelf, observed ocean cooling of 4.5�C was caused by upwelling processes induced by wind stress and an offshore wind-driven transport. During Hurricane Lili, ocean cooling in the LC was ~1�C but more than 2�C in the Gulf Common Water, where the maximum estimated surface enthalpy flux was 1.4 kW m^-2, associated with peak surface winds of 51 m s^-1. Because of Lili's asymmetric structure and rapid translational speed of 7 m s^-1, the maximum surface heat loss resulting from the surface enthalpy flux was less than 5 kJ cm^-2. In both hurricanes, the weak ocean thermal response in the LC was primarily due to the lack of energetic near-inertial current shears that develop across the thin OML observed in quiescent regimes. Bulk Richardson numbers remained well above criticality because of the strength of the upper-ocean horizontal pressure gradient that forces northward current and thermal advection of warm water distributed over deep layers. As these oceanic regimes are resistive to shear-induced mixing, hurricanes experience a more sustained surface enthalpy flux compared to storms moving over shallow quiescent mixed layers. Because ocean cooling levels induced by hurricane force winds depend on the underlying oceanic regimes, features must be accurately initialized in coupled forecast models.

Smith, R.K., and M.T. Montgomery. Balanced boundary layers used in hurricane models. Quarterly Journal of the Royal Meteorological Society, 134(635):1385-1395 (2008).

We examine the formulation and accuracy of various approximations made in representing the boundary layer in simple axisymmetric hurricane models, especially those that assume strict gradient wind balance in the radial direction. Approximate solutions for a steady axisymmetric slab boundary-layer model are compared with a full model solution. It is shown that the approximate solutions are generally poor in the inner core region of the vortex, where the radial advection term in the radial momentum equation is important and cannot be neglected. These results affirm some prior work and have implications for a range of theoretical studies of vhurricane dynamics, including theories of potential intensity, that employ balanced boundary-layer formulations.

Smith, R.K., M.T. Montgomery, and S. Vogl. A critique of Emanuel's hurricane model and potential intensity theory. Quarterly Journal of the Royal Meteorological Society, 134(632):551-561 (2008).

We present a critique of Emanuel's steady-state hurricane model, which is a precursor to his theory for hurricane potential intensity (PI). We show that a major deficiency of the theory is the tacit assumption of gradient wind balance in the boundary layer, a layer that owes its existence to gradient wind imbalance in the radial momentum equation. If a more complete boundary-layer formulation is included using the gradient wind profiles obtained from Emanuel's theory, the tangential wind speed in the boundary layer becomes supergradient, invalidating the assumption of gradient wind balance. We show that the degree to which the tangential wind is supergradient depends on the assumed boundary-layer depth. The full boundary-layer solutions require a knowledge of the tangential wind profile above the boundary layer in the outer region where there is subsidence into the layer and they depend on the breadth of this profile. This effect is not considered in Emanuel's theory. We argue that a more complete theory for the steady-state hurricane would require the radial pressure gradient above the boundary layer to be prescribed or determined independently of the boundary layer. The issues raised herein highlight a fundamental problem with Emanuel's theory for PI, since that theory makes the same assumptions as in the steady-state hurricane model. Our current findings together with recent studies examining intense hurricanes suggest a way forward towards a more consistent theory for hurricane PI.

Stern, D.P., D.S. Nolan, and S.D. Aberson. Simulations and observations of extreme low-level updrafts in Hurricane Isabel. Extended Abstracts, 28th Conference on Hurricanes and Tropical Meteorology, Orlando, Florida, April 28-May 2, 2008. American Meteorological Society, Boston, 6 pp. (2008).

No abstract.

Stewart, J.R., R.J. Gast, R.S. Fujioka, H.M. Solo-Gabriele, J.S. Meschke, L.A. Amaral-Zettler, E. Del Castillo, M.F. Polz, T.K. Collier, M.S. Strom, C.D. Sinigalliano, P.D.R. Moeller, and A.F. Holland. The coastal environment and human health: Microbial indicators, pathogens, sentinels and reservoirs. Environmental Health, 7(Suppl. 2):S3, doi:10.1186/1476-069X-7-S2-S3 (2008).

Innovative research relating oceans and human health is advancing our understanding of disease-causing organisms in coastal ecosystems. Novel techniques are elucidating the loading, transport and fate of pathogens in coastal ecosystems, and identifying sources of contamination. This research is facilitating improved risk assessments for seafood consumers and those who use the oceans for recreation. A number of challenges still remain and define future directions of research and public policy. Sample processing and molecular detection techniques need to be advanced to allow rapid and specific identification of microbes of public health concern from complex environmental samples. Water quality standards need to be updated to more accurately reflect health risks and to provide managers with improved tools for decision-making. Greater discrimination of virulent versus harmless microbes is needed to identify environmental reservoirs of pathogens and factors leading to human infections. Investigations must include examination of microbial community dynamics that may be important from a human health perspective. Further research is needed to evaluate the ecology of non-enteric water-transmitted diseases. Sentinels should also be established and monitored, providing early warning of dangers to ecosystem health. Taken together, this effort will provide more reliable information about public health risks associated with beaches and seafood consumption, and how human activities can affect their exposure to disease-causing organisms from the oceans.

Swart, S., S. Speich, I.J. Ansorge, G.J. Goni, S. Gladyshev, and J.R.E. Lutjeharms. Transport and variability of the Antarctic Circumpolar Current south of Africa. Journal of Geophysical Research, 113(C9):C09014, doi:10.1029/2007JC004223 (2008).

Data from five CTD and 18 XBT sections are used to estimate the baroclinic transport (referenced to 2500 dbar) of the ACC south of Africa. Surface dynamic height is derived from XBT data by establishing an empirical relationship between vertically integrated temperature and surface dynamic height calculated from CTD data. This temperature-derived dynamic height data compare closely with dynamic heights calculated from CTD data (average RMS difference = 0.05 dyn m). A second empirical relationship between surface dynamic height and cumulative baroclinic transport is defined, allowing us to study a more extensive time series of baroclinic transport derived from upper ocean temperature sections. From 18 XBT transects of the ACC, the average baroclinic transport, relative to 2500 dbar, is estimated at 90 � 2.4 Sv. This estimate is comparable to baroclinic transport values calculated from CTD data. We then extend the baroclinic transport time-series by applying an empirical relationship between dynamic height and cumulative baroclinic transport to weekly maps of absolute dynamic topography derived from satellite altimetry, between 14 October 1992 and 23 May 2007. The estimated mean baroclinic transport of the ACC, obtained this way, is 84.7 � 3.0 Sv. These transports agree well with simultaneous in-situ estimates (RMS difference in net transport = 5.2 Sv). This suggests that sea level anomalies largely reflect baroclinic transport changes above 2500 dbar.

Tao, W.-K., D. Anderson, R. Atlas, J. Chern, P. Houser, A. Hou, S. Lang, W. Lau, C. Peters-Lidard, R. Kakar, S. Kumar, W. Lapenta, X. Li, T. Matsui, M. Rienecker, B.-W. Shen, J.J. Shi, J. Simpson, and X. Zeng. A Goddard multi-scale modeling system with unified physics. GEWEX News, 18(1):6-8 (2008).

No abstract.

Terwey, W.D., and M.T. Montgomery. Secondary eyewall formation in two idealized, full-physics modeled hurricanes. Journal of Geophysical Research, 113(D12):D12112, doi:10.1029/2007JD0088979 (2008).

Prevailing hypotheses for secondary eyewall formation are examined using data sets from two high-resolution mesoscale numerical model simulations of the long-time evolution of an idealized hurricane vortex in a quiescent tropical environment with constant background rotation. The modeled hurricanes each undergo a secondary eyewall cycle, casting doubt on a number of other authors' hypotheses for secondary eyewall formation due to idealizations present in the simulation formulations. A new hypothesis for secondary eyewall formation is proposed here and is shown to be supported by these high-resolution numerical simulations. The hypothesis requires the existence of a region with moderate horizontal strain deformation and a sufficient low-level radial potential vorticity gradient associated with the primary swirling flow, moist convective potential, and a wind-moisture feedback process at the air-sea interface to form the secondary eyewall. The crux of the formation process is the generation of a finite-amplitude lower-tropospheric cyclonic jet outside the primary eyewall with a jet width on the order of a local effective beta scale determined by the mean low-level radial potential vorticity gradient and the root-mean square eddy velocity. This jet is hypothesized to be generated by the anisotropic upscale cascade and axisymmetrization of convectively generated vorticity anomalies through horizontal shear turbulence and sheared vortex Rossby waves as well as by the convergence of system-scale cyclonic vorticity by the low-level radial inflow associated with the increased convection. Possible application to the problem of forecasting secondary eyewall events is briefly considered.

Thacker, W.C. Estimating salinity between 25�S and 45�S in the Atlantic Ocean using local regression. Journal of Atmospheric and Oceanic Technology, 25(1):114-130 (2008).

The empirical relationship between salinity and temperature in the South Atlantic is quantified with the aid of local regression. To capture the spatial character of the TS relationship, models are fitted to data for each point on a three-dimensional grid with spacing of 1� in latitude, 2� in longitude, and 25 dbar in the vertical. To ensure sufficient data for statistical reliability each fit is to data from a region extending over several grid points weighted so that more remote data exert less influence than those closer to the target grid point. Both temperature and its square are used as regressors to capture the curvature seen in TS plots, and latitude and longitude are used to capture systematic spatial variations over the fitting regions. In addition to using statistics of residuals to characterize how well the models fit the data, errors for data not used in fitting are examined to verify the models' abilities to simulate independent data. The best model overall for the entire region at all depths is quadratic in temperature and linear in longitude and latitude.

Thomas, H., A.E.F. Prowe, I.D. Lima, S.C. Doney, R. Wanninkhof, R.J. Greatbatch, U. Schuster, and A. Corbiere. Changes in the North Atlantic Oscillation influence CO₂ uptake in the North Atlantic over the past two decades. Global Biogeochemical Cycles, 22(4):GB4027, doi:10.1029/2007GB003167 (2008).

Observational studies report a rapid decline of ocean CO₂ uptake in the temperate North Atlantic during the last decade. We analyze these findings using ocean physical-biological numerical simulations forced with interannually varying atmospheric conditions for the period 1979-2004. In the simulations, surface ocean water mass properties and CO₂ system variables exhibit substantial multiannual variability on sub-basin scales in response to wind-driven reorganization in ocean circulation and surface warming/cooling. The simulated temporal evolution of the ocean CO₂ system is broadly consistent with reported observational trends and is influenced substantially by the phase of the North Atlantic Oscillation (NAO). Many of the observational estimates cover a period after 1995 of mostly negative or weakly positive NAO conditions, which are characterized in the simulations by reduced North Atlantic Current transport of subtropical waters into the eastern basin and by a decline in CO₂ uptake. We suggest therefore that air-sea CO₂ uptake may rebound in the eastern temperate North Atlantic during future periods of more positive NAO, similar to the patterns found in our model for the sustained positive NAO period in the early 1990s. Thus, our analysis indicates that the recent rapid shifts in CO₂ flux reflect decadal perturbations superimposed on more gradual secular trends. The simulations highlight the need for long-term ocean carbon observations and modeling to fully resolve multiannual variability, which can obscure detection of the long-term changes associated with anthropogenic CO₂ uptake and climate change.

Tory, K.J., and M.T. Montgomery. Tropical cyclone formation: A synopsis of the system-scale development. Extended Abstracts, 28th Conference on Hurricanes and Tropical Meteorology, Orlando, Florida, April 28-May 2, 2008. American Meteorological Society, Boston, 6 pp. (2008).

No abstract.

Uhlhorn, E.W. Gulf of Mexico Loop Current mechanical energy and vorticity response to a tropical cyclone. Ph.D. thesis, University of Miami, Rosenstiel School of Marine and Atmospheric Science, 148 pp. (2008).

The ocean mixed layer response to a tropical cyclone within, and immediately adjacent to, the Gulf of Mexico Loop Current is examined using a combination of ocean profiles and a numerical model. A comprehensive set of temperature, salinity, and current profiles acquired from aircraft-deployed expendable probes is utilized to analyze the three-dimensional oceanic energy and circulation evolution in response to Hurricane Lili's (2002) passage. Mixed-layer temperature analyses show that the Loop Current cooled <1°C in response to the storm, in contrast to typically observed larger decreases of 3-5°C. Correspondingly, vertical current shears, which are partly responsible for entrainment mixing, were found to be up to 50% weaker, on average, than observed in previous studies within the directly-forced region. The Loop Current, which separates the warmer, lighter Caribbean Subtropical water from the cooler, heavier Gulf Common water, was found to decrease in intensity by -0.18 ± 0.25 m s^-1 over an approximately 10-day period within the mixed layer. Contrary to previous tropical cyclone ocean response studies which have assumed an approximately horizontally homogeneous ocean structure prior to storm passage, a kinetic energy loss of 5.8 ± 6.3 k Jm^-2, or approximately 1 wind stress-scaled energy unit, was observed. Using near-surface currents derived from satellite altimetry data, the Loop Current is found to vary similarly in magnitude, suggesting storm-generated energy is rapidly removed by the pre-existing Loop Current. Further examination of the energy response using an idealized numerical model reveals that due to: (1) favorable coupling between the wind stress and pre-existing current vectors; and (2) wind-driven currents flowing across the large horizontal pressure gradient; wind energy transfer to mixed-layer kinetic energy can be more efficient in these regimes as compared to the case of an initially horizontally homogeneous ocean. However, nearly all of this energy is removed by advection by 2 local inertial periods after storm passage, and little evidence of the storms impact remains. Mixed-layer vorticity within the idealized current also shows a strong direct response, but little evidence of a near-inertial wave wake results.

Voss, D., H. Maring, and K.D. Goodwin. Production of salt aerosol and bioaerosol from a sea-salt aerosol generator. In Marine Pollution: New Research, T.N. Hofer (ed.). Nova Science Publishers, Inc., New York, 398-429 (2008).

No abstract.

Wang, C., and S.-K. Lee. Global warming and United States landfalling hurricanes. Geophysical Research Letters, 35(2):L02708, doi:10.1029/2007GL032396 (2008).

A secular warming of sea surface temperature occurs almost everywhere over the global ocean. Here we use observational data to show that global warming of the sea surface is associated with a secular increase of tropospheric vertical wind shear in the main development region (MDR) for Atlantic hurricanes. The increased wind shear coincides with a weak but robust downward trend in U.S. landfalling hurricanes, a reliable measure of hurricanes over the long term. Warmings over the tropical oceans compete with one another, with the tropical Pacific and Indian Oceans increasing wind shear and the tropical North Atlantic decreasing wind shear. Warmings in the tropical Pacific and Indian Oceans win the competition and produce increased wind shear which reduces U.S. landfalling hurricanes. Whether future global warming increases the vertical wind shear in the MDR for Atlantic hurricanes will depend on the relative role induced by secular warmings over the tropical oceans.

Wang, C., S.-K. Lee, and D.B. Enfield. Atlantic warm pool acting as a link between Atlantic multidecadal oscillation and Atlantic tropical cyclone activity. Geochemistry Geophysics Geosystems, 9:Q05V03, doi:10.1029/2007GC001809 (2008).

Multidecadal variability of Atlantic tropical cyclone activity is observed to relate to the Atlantic Multidecadal Oscillation (AMO), a mode manifesting primarily in sea surface temperature (SST) in the high latitudes of the North Atlantic. In the low latitudes of the North Atlantic, a large body of warm water called the Atlantic Warm Pool (AWP) comprises the Gulf of Mexico, the Caribbean Sea, and the western tropical North Atlantic. AWP variability occurs on both interannual and multidecadal timescales as well as with a secular variation. The AWP multidecadal variability coincides with the signal of the AMO; that is, the warm (cool) phases of the AMO are characterized by repeated large (small) AWPs. Since the climate response to the North Atlantic SST anomalies is primarily forced at the low latitudes and the AWP is in the path of or a birthplace for Atlantic tropical cyclones, the influence of the AMO on Atlantic tropical cyclone activity may operate through the mechanism of the AWP-induced atmospheric changes. The AWP-induced changes related to tropical cyclones that we emphasize here include a dynamical parameter of tropospheric vertical wind shear and a thermodynamical parameter of convective instability. More specifically, an anomalously large (small) AWP reduces (enhances) the vertical wind shear in the hurricane main development region and increases (decreases) the moist static instability of the troposphere, both of which favor (disfavor) Atlantic tropical cyclone activity. This is the most plausible way in which the AMO relationship with Atlantic tropical cyclones can be understood.

Wang, C., S.-K. Lee, and D.B. Enfield. Climate response to anomalously large and small Atlantic warm pools during the summer. Journal of Climate, 21(11):2437-2450 (2008).

This paper uses the NCAR Community Atmospheric Model to show the influence of Atlantic warm pool (AWP) variability on the summer climate and Atlantic hurricane activity. The model runs show that the climate response to the AWP's heating extends beyond the AWP region to other regions such as the eastern North Pacific. Both the sea level pressure and precipitation display a significant response of low (high) pressure and increased (decreased) rainfall to an anomalously large (small) AWP, in areas with two centers located in the western tropical North Atlantic and in the eastern North Pacific. The rainfall response suggests that an anomalously large (small) AWP suppresses (enhances) the midsummer drought, a phenomenon with a diminution in rainfall during July and August in the region around Central America. In response to the pressure changes, the easterly Caribbean low-level jet is weakened (strengthened), as is its westward moisture transport. An anomalously large (small) AWP weakens (strengthens) the southerly Great Plains low-level jet, which results in reduced (enhanced) northward moisture transport from the Gulf of Mexico to the United States east of the Rocky Mountains and thus decreases (increases) the summer rainfall over the central United States, in agreement with observations. An anomalously large (small) AWP also reduces (enhances) the tropospheric vertical wind shear in the main hurricane development region and increases (decreases) the moist static instability of the troposphere, both of which favor (disfavor) the intensification of tropical storms into major hurricanes. Since the climate response to the North Atlantic SST anomalies is primarily forced at low latitudes, this study implies that reduced (enhanced) rainfall over North America and increased (decreased) hurricane activity due to the warm (cool) phase of the Atlantic multidecadal oscillation may be partly due to the AWP-induced changes of the northward moisture transport and the vertical wind shear and moist static instability associated with more frequent large (small) summer warm pools.

Westerink, J.J., R.A. Luettich, J.C. Feyen, J.H. Atkinson, C. Dawson, H.J. Roberts, M.D. Powell, J.P. Dunion, E.J. Kubatko, and H. Pourtaheri. A basin- to channel-scale unstructured grid hurricane storm surge model applied to southern Louisiana. Monthly Weather Review, 136(3):833-864 (2008).

Southern Louisiana is characterized by low-lying topography and an extensive network of sounds, bays, marshes, lakes, rivers, and inlets that permit widespread inundation during hurricanes. A basin- to channel-scale implementation of the Advanced Circulation (ADCIRC) unstructured grid hydrodynamic model has been developed that accurately simulates hurricane storm surge, tides, and river flow in this complex region. This is accomplished by defining a domain and computational resolution appropriate for the relevant processes, specifying realistic boundary conditions, and implementing accurate, robust, and highly parallel unstructured grid numerical algorithms. The model domain incorporates the western North Atlantic, the Gulf of Mexico, and the Caribbean Sea so that interactions between basins and the shelf are explicitly modeled and the boundary condition specification of tidal and hurricane processes can be readily defined at the deep water open boundary. The unstructured grid enables highly refined resolution of the complex overland region for modeling localized scales of flow while minimizing computational cost. Kinematic data assimilative or validated dynamic-modeled wind fields provide the hurricane wind and pressure field forcing. Wind fields are modified to incorporate directional boundary layer changes due to overland increases in surface roughness, reduction in effective land roughness due to inundation, and sheltering due to forested canopies. Validation of the model is achieved through hindcasts of Hurricanes Betsy and Andrew. A model skill assessment indicates that the computed peak storm surge height has a mean absolute error of 0.30 m.

Zhang, J.A., P.G. Black, J.R. French, and W.M. Drennan. First direct measurements of enthalpy flux in the hurricane boundary layer: The CBLAST results. Geophysical Research Letters, 35(11):L14813, doi:10.1029/2008GL034374 (2008).

Hurricanes extract energy from the warm ocean through enthalpy fluxes. As part of the Coupled Boundary Layer Air-Sea Transfer (CBLAST) experiment, flights were conducted to measure turbulent fluxes in the high-wind boundary layer of hurricanes. Here we present the first field observations of sensible heat and enthalpy flux for 10m wind speeds to 30 m s^-1. The analyses indicate no statistically significant dependence of these bulk exchange coefficients on wind speed. As a measure of hurricane development potential, we compute the mean ratio of the exchange coefficient for enthalpy to that for momentum and find it to be significantly below the lowest threshold estimated by previous investigators. This suggests that the enthalpy flux required for hurricane development may come from sources other than turbulent fluxes, such as lateral fluxes from the vortex warm core, or sea spray. Alternatively, it demands a re-evaluation of the theoretical models used to derive the threshold.

Zhang, J.A., K.B. Katsaros, P.G. Black, S. Lehner, J.R. French, and W.M. Drennan. Effects of roll vortices on turbulent fluxes in the hurricane boundary layer. Boundary-Layer Meteorology, 128(2):173-189 (2008).

Boundary-layer secondary circulations or "roll vortices" can have a significant influence on the turbulent exchange of momentum, sensible heat and moisture throughout the hurricane boundary layer. In this study, analyses of data from a WP-3D aircraft of the National Oceanic and Atmospheric Administration (NOAA) are presented. As part of the Coupled Boundary Layer Air-Sea Transfer (CBLAST)-hurricane experiment sponsored through the Office of Naval Research and NOAA's annual hurricane research program, flights were conducted to investigate energy exchange across the air-sea interface. We present the first in-situ aircraft-based observations of rolls in the hurricane boundary layer and investigate their influence on energy and momentum exchange. The rolls detected in Hurricane Isidore (year 2002) have a characteristic wavelength of about 900 m, in good agreement with analyses of data from a synthetic aperture radar image captured by the Canadian Space Agency's RADARSAT satellite in the same storm. Our analyses of the airborne data suggest that roll vortices may be a significant factor modulating the air-sea momentum exchange. **2007**

Atlas, R., S.-J. Lin, B.-W. Shen, O. Reale, and K.-S. Yeh. Improving hurricane prediction through innovative global modeling. In Extending the Horizons: Advances in Computing, Optimization, and Decision Technologies, E.K. Baker, A. Joseph, A. Mehrotra, and M.A. Trick (eds.). Springer, 1-14 (2007).

Current global and regional models incorporating both in situ and remotely sensed observations have achieved a high degree of skill in forecasting the movement of hurricanes. Nevertheless, significant improvements in the prediction of hurricane landfall and intensification are still needed. To meet these needs, research on new observing systems, data assimilation techniques, and better models is being performed. These include the Hurricane Weather Research and Forecasting regional model development by NOAA, as well as the development of an advanced "seamless" global weather and climate model, as a collaborative project involving both NOAA and NASA. This latter model, when completed, will be used to improve short and extended range forecasts of hurricanes, as well as to determine the relationship between global climate change and long-term variations in hurricane frequency and intensity, more accurately than is possible today. As a starting point for the seamless global weather and climate model, the horizontal resolution of the previously developed finite volume General Circulation Model has been increased to 1/12° (approximately 9 km) in a series of success steps. This was made possible by advances in both computing and optimization technologies.

Atlas, R., O. Reale, J. Ardizzone, J. Terry, J.-C. Jusem, E. Brin, D. Bungato, and J.F. Le Marshall. Evaluation of WINDSAT surface wind data and its impact on ocean surface wind analyses and numerical weather prediction. Preprints, 11th Symposium on Integrated Observing and Assimilation Systems for the Atmosphere, Oceans, and Land Surface (IOAS-AOLS), San Antonio, TX, January 14-18, 2007. American Meteorological Society, Boston, CD-ROM, 6 pp. (2007).

A detailed evaluation of the latest version of WINDSAT surface wind data has recently been performed to determine the quality of these data and their usefulness for ocean surface wind analysis and numerical weather prediction. The first component of this evaluation consisted of both subjective and objective comparisons of WINDSAT wind vectors to other sources of ocean surface winds (e.g., ship and buoy observations, QuikSCAT satellite winds, or model derived wind analyses). This was followed by data impact experiments using a variational surface wind analysis, as well as an operational four-dimensional data assimilation system. The results of this evaluation demonstrate the usefulness of WINDSAT data, but also show deficiencies relative to current scatterometer measurements.

Baringer, M.O., and S.L. Garzoli. Meridional heat transport determined with expendable bathythermographs, Part I: Error estimates from model and hydrographic data. Deep-Sea Research, Part I, 54(8):1390-1401 (2007).

Heat transports estimated from CTD data collected during the World Ocean Circulation Experiment (WOCE) along the January 1993 30�S hydrographic transect (A10) and the output from a numerical model show a mean heat transport of 0.40 and 0.55�0.24 PW (standard deviation), respectively. The model shows a large annual cycle in heat transport (more than 30% of the variance) with a maximum (minimum) heat transport in July (February) of 0.68 (0.41) PW. Using these data, a method is proposed and evaluated to calculate the heat transport from temperature data obtained from a trans-basin section of expendable bathythermographs (XBTs) profiles. In this method, salinity is estimated from Argo profiles and CTD casts for each XBT temperature observation using statistical relationships between temperature, latitude, longitude, and salinity computed along constant-depth surfaces. Full-depth temperature/salinity profiles are obtained by extending the profiles to the bottom of the ocean using deep climatological data. The meridional transport is then determined by using the standard geostrophic method, applying NCEP-derived Ekman transports, and requiring that the salt flux through the Bering Straits be conserved. The results indicate that the methods described here can provide heat transport estimates with a maximum uncertainty of �0.18 PW (1 PW=10¹⁵ W). Most of this uncertainty is due to the climatology used to estimate the deep structure and issues related to not knowing the absolute velocity field and most especially characterizing barotropic motions. Nevertheless, when the methodology is applied to temperatures collected along 30�S (A10) and direct model integrations, the results are very promising. Results from the numerical model suggest that ageostrophic non-Ekman motions can contribute less than 0.05 PW to heat transport estimates in the South Atlantic.

Baringer, M.O., and C.S. Meinen. Global oceans: The meridional overturning circulation and oceanic heat transport. In State of the Climate in 2006, A. Arguez, A.M. Waple, and A.M. Sanchez-Lugo (eds.). Bulletin of the American Meteorological Society, 88(6):S38-S39 (2007).

No abstract.

Baums, I.B., K.D. Goodwin, T.L. Kiesling, D. Wanless, M.R. Diaz, and J.W. Fell. Luminex detection of fecal indicators in river samples, marine recreational water, and beach sand. Marine Pollution Bulletin, 54(5):521-536 (2007).

Research to understand and remediate coastal pollution is moving toward a multitiered approach in which traditional enumeration of fecal indicators is accompanied by molecular analysis of a variety of targets. Technology that rapidly detects multiple microbial contaminants would benefit from such an approach. The Luminex 100 system is a suspension array that assays multiple analytes rapidly in a single well of a microtiter plate. The ability of the system to simultaneously detect multiple fecal indicating bacteria in environmental samples was tested. Primer/probe sets were designed to simultaneously detect the following fecal indicators: the Bacteroides fragilis group, Enterococcus spp., Escherichia coli and Shigella spp., Bacteroides distasonis, and Ent. faecalis. Specificity and sensitivity of the Luminex probes was tested against laboratory cultures. In addition, sequencing, culture plate testing, and specificity testing with environmental isolates were steps taken to validate the function of the assay with environmental samples. Luminex response to cultures and to environmental samples was consistent with sequencing results, suggesting that the technology has the potential to simultaneously detect multiple targets for coastal water quality applications, particularly as progress is made to efficiently extract DNA from water and sediment matrices.

Bell, G.D., E. Blake, C.W. Landsea, M. Chelliah, R. Pasch, K.C. Mo, and S.B. Goldenberg. The tropics: Tropical cyclones-Atlantic basin. In State of the Climate in 2006, A. Arguez, A.M. Waple, and A.M. Sanchez-Lugo (eds.). Bulletin of the American Meteorological Society, 88(6):S48-S51 (2007).

No abstract.

Black, P.G., E.A. D'Asaro, W.M. Drennan, J.R. French, P.P. Niiler, T.B. Sanford, E.J. Terrill, E.J. Walsh, and J.A. Zhang. Air-sea exchange in hurricanes: Synthesis of observations from the Coupled Boundary Layer Air-Sea Transfer Experiment. Bulletin of the American Meteorological Society, 88(3):357-374 (2007).

The Coupled Boundary Layer Air-Sea Transfer (CBLAST) field program, conducted from 2002 to 2004, has provided a wealth of new air-sea interaction observations in hurricanes. The wind speed range for which turbulent momentum and moisture exchange coefficients have been derived based upon direct flux measurements has been extended by 30% and 60%, respectively, from airborne observations in Hurricanes Fabian and Isabel in 2003. The drag coefficient (CD) values derived from CBLAST momentum flux measurements show CD becoming invariant with wind speed near a 23 m s^-1 threshold rather than a hurricane-force threshold near 33 m s^-1. Values above 23 m s^-1 are lower than previous open-ocean measurements. The Dalton number estimates (CE) derived from CBLAST moisture flux measurements are shown to be invariant with wind speeds up to 30 m s^-1, which is in approximate agreement with previous measurements at lower winds. These observations imply a CE/CD ratio of approximately 0.7, suggesting that additional energy sources are necessary for hurricanes to achieve their maximum potential intensity. One such additional mechanism for augmented moisture flux in the boundary layer might be "roll vortex" or linear coherent features, observed by CBLAST 2002 measurements to have wavelengths of 0.9-1.2 km. Linear features of the same wavelength range were observed in nearly concurrent RADARSAT Synthetic Aperture Radar (SAR) imagery. As a complement to the aircraft measurement program, arrays of drifting buoys and subsurface floats were successfully deployed ahead of Hurricanes Fabian (2003) and Frances (2004) [16 (6) and 38 (14) drifters (floats), respectively, in the two storms]. An unprecedented set of observations was obtained, providing a four-dimensional view of the ocean response to a hurricane for the first time ever. Two types of surface drifters and three types of floats provided observations of surface and sub-surface oceanic currents, temperature, salinity, gas exchange, bubble concentrations, and surface wave spectra to a depth of 200 m on a continuous basis before, during, and after storm passage, as well as surface atmospheric observations of wind speed (via acoustic hydrophone) and direction, rain rate, and pressure. Float observations in Frances (2004) indicated a deepening of the mixed layer from 40 to 120 m in approximately 8 h, with a corresponding decrease in SST in the right-rear quadrant of 3.2�C in 11 h, roughly one-third of an inertial period. Strong inertial currents with a peak amplitude of 1.5 m s^-1 were observed. Vertical structure showed that the critical Richardson number was reached sporadically during the mixed-layer deepening event, suggesting shear-induced mixing as a prominent mechanism during storm passage. Peak significant waves of 11 m were observed from the floats to complement the aircraft-measured directional wave spectra.

Borges, A.V., and R. Wanninkhof. Preface: 37th International Liege Colloquium on Ocean Dynamics, Liege, Belgium, May 2-6, 2005, 5th International Symposium on Gas Transfer at Water Surfaces. Journal of Marine Systems, 66(1-4):1-3 (2007).

No abstract.

Bourles, B., P. Brandt, G. Caniaux, M. Dengler, Y. Gouriou, E. Key, R. Lumpkin, F. Marin, R.L. Molinari, and C. Schmid. African Monsoon Multidisciplinary Analysis (AMMA): Special measurements in the tropical Atlantic. CLIVAR Exchanges, 12(2):7-9 (2007).

No abstract.

Broecker, W.S., and R. Wanninkhof. Mono Lake radiocarbon: The mystery deepens. EOS, Transactions, American Geophysical Union, 88(12):141-142 (2007).

The ratio of carbon-14 (¹⁴C) to carbon in the dissolved inorganic carbon (SIGMA-CO₂) of California's Mono Lake has continued to rise at a rate far faster than expected from the invasion of bomb-test ¹⁴C-labeled atmospheric CO₂. Two explanations can be given. One is that the invasion rate of carbon dioxide from the atmosphere is 5 or so times higher than that for chemically inert gases. The second is that Mono Lake has been used as a site for clandestine disposal of radiocarbon.

Carrasco, H.N. Data mining assisted automated quality control of tropical cyclone wind data. M.S. thesis, University of Miami, Rosenstiel School of Marine and Atmospheric Science, 82 pp. (2007).

Meteorological observations are collected around the world in real-time to help meteorologists understand severe weather events, such as tropical cyclones. Tropical cyclones affect life on much of the world's coastlines. Data from meteorological observations are utilized by many models and analysis systems to help predict tropical cyclones and increase meteorologists' understanding of them. Data mining techniques such as clustering are useful tools that help find patterns within data. Particularly, a key aspect of most spatial clustering algorithms is their ability to detect noise. In the area of tropical cyclone quality control, this noise is the data that needs to be removed before scheduling an analysis. DBSCAN is an existing clustering algorithm that can locate patterns based on the density of observations to find complex shapes and eliminate noise, and thus is adopted in this study. In this thesis, the H*Wind-DBSCAN framework was designed and implemented to create a data mining tool that assists automated quality control within H*Wind for the various observations collected in and around tropical cyclones. H*Wind is a tool used to monitor and analyze tropical cyclone data around the globe. Combining many platforms of different observing systems, H*Wind allows meteorologists to interact with observation data. However, the quality control process is a slow and difficult task performed manually. Depending on the number of available observations the process can take from only a few minutes to sometimes over half an hour. Therefore, the H*Wind-DBSCAN framework was designed and developed using knowledge about the structure of a tropical cyclone in an attempt to efficiently and effectively cluster observations using DBSCAN. The H*Wind-DBSCAN framework flags those observations considered noise by DBSCAN and prevents them from being used in the analysis process. Typical spatial clustering routines cluster data points using the distance between two data points on a single coordinate plane. The proposed H*Wind-DBSCAN framework integrates the Cartesian Coordinate System and Cylindrical Coordinate System based on the circulation found within tropical cyclones in order to more accurately construct clusters. Several case studies were conducted, and the results demonstrate that the proposed H*Wind-DBSCAN framework improves the overall automated quality control performance as compared to using either coordinate system alone. Using the framework, the resulting flagged observations are helpful to determine areas of interest for a closer examination and to construct a decent quality controlled data set for the tropical cyclone wind analysis system.

Cerveny, R.S., J. Lawrimore, R. Edwards, and C.W. Landsea. Extreme weather records: Compilation, adjudication, and publication. Bulletin of the American Meteorological Society, 88(6):853-860 (2007).

No abstract.

Chavez, F.P., T. Takahashi, W.-J. Cai, G. Friederich, B. Hales, R. Wanninkhof, and R.A. Feely. Coastal oceans, pp. 157-166. In The First State of the Carbon Cycle Report (SOCCR): The North American Carbon Budget and Implications for the Global Carbon Cycle. Report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research, A.W. King, L. Dilling, G.P. Zimmerman, D.M. Fairman, R.A. Houghton, G. Marland, A.Z. Rose, and T.J. Wilbanks (eds.). National Oceanic and Atmospheric Administration, National Climatic Data Center, Asheville, NC, USA, 264 pp. (2007).

No abstract.

Conzemius, R.J., R.W. Moore, M.T. Montgomery, and C.A. Davis. Mesoscale convective vortex formation in a weakly sheared moist neutral environment. Journal of the Atmospheric Sciences, 64(5):1443-1466 (2007).

Idealized simulations of a diabatic Rossby vortex (DRV) in an initially moist neutral baroclinic environment are performed using the fifth-generation National Center for Atmospheric Research-Pennsylvania State University (NCAR-PSU) Mesoscale Model (MM5). The primary objective is to test the hypothesis that the formation and maintenance of midlatitude warm-season mesoscale convective vortices (MCVs) are largely influenced by balanced flow dynamics associated with a vortex that interacts with weak vertical shear. As a part of this objective, the simulated DRV is placed within the context of the Bow Echo and Mesoscale Convective Vortex Experiment (BAMEX) field campaign by comparing its tangential velocity, radius of maximum winds, CAPE, and shear with the MCVs observed in BAMEX. The simulations reveal two distinct scales of development. At the larger scale, the most rapidly growing moist baroclinic mode is excited, and exponential growth of this mode occurs during the simulation. Embedded within the large-scale baroclinic wave is a convective system exhibiting the characteristic DRV development, with a positive potential vorticity (PV) anomaly in the lower troposphere and a negative PV anomaly in the upper troposphere, and the positive/negative PV doublet tilted downshear with height. The DRV warm-air advection mechanism is active, and the resulting deep convection helps to reinforce the DRV against the deleterious effects of environmental shear, causing an eastward motion of the convective system as a whole. The initial comparisons between the simulated DRVs and the BAMEX MCVs show that the simulated DRVs grew within background conditions of CAPE and shear similar to those observed for BAMEX MCVs and suggest that the same dynamical mechanisms are active. Because the BAMEX field campaign sampled MCVs in different backgrounds of CAPE and shear, the comparison also demonstrates the need to perform additional simulations to explore these different CAPE and shear regimes and to understand their impacts on the intensity and longevity of MCVs. Such a study has the additional benefit of placing MCV dynamics in an appropriate context for exploring their relevance to tropical cyclone formation.

Cram, T.A., J. Persing, M.T. Montgomery, and S.A. Braun. A Lagrangian trajectory view on transport and mixing processes between the eye, eyewall, and environment using a high-resolution simulation of Hurricane Bonnie (1998). Journal of the Atmospheric Sciences, 64(6):1835-1856 (2007).

The transport and mixing characteristics of a large sample of air parcels within a mature and vertically sheared hurricane vortex are examined. Data from a high-resolution (2-km horizontal grid spacing) numerical simulation of real-case Hurricane Bonnie (1998) are used to calculate Lagrangian trajectories of air parcels in various subdomains of the hurricane (namely, the eye, eyewall, and near environment) to study the degree of interaction (transport and mixing) between these subdomains. It is found that: (1) there is transport and mixing from the low-level eye to the eyewall that carries air possessing relatively high values of equivalent potential temperature (theta_e), which can enhance the efficiency of the hurricane heat engine; (2) a portion of the low-level inflow of the hurricane bypasses the eyewall to enter the eye, and this air both replaces the mass of the low-level eye and lingers for a sufficient time (order 1 h) to acquire enhanced entropy characteristics through interaction with the ocean beneath the eye; (3) air in the mid- to upper-level eye is exchanged with the eyewall such that more than half the air of the eye is exchanged in 5 h in this case of a sheared hurricane; and (4) that one-fifth of the mass in the eyewall at a height of 5 km has an origin in the mid- to upper-level environment where theta_e is much less than in the eyewall, which ventilates the ensemble average eyewall theta_e by about 1 K. Implications of these findings for the problem of hurricane intensity forecasting are briefly discussed.

Cunningham, S.A., T. Kanzow, D. Rayner, M.O. Baringer, W.E. Johns, J. Marotzke, H.R. Longworth, E.M. Grant, J.J-M. Hirschi, L.M. Beal, C.S. Meinen, and L.H. Bryden. Temporal variability of the Atlantic meridional overturning circulation at 26.5�N. Science, 317(5840):935-938 (2007).

The vigor of Atlantic meridional overturning circulation (MOC) is thought to be vulnerable to global warming, but its short-term temporal variability is unknown so changes inferred from sparse observations on the decadal time scale of recent climate change are uncertain. We combine continuous measurements of the MOC (beginning in 2004) using the purposefully designed transatlantic Rapid Climate Change array of moored instruments deployed along 26.5�N, with time series of Gulf Stream transport and surface-layer Ekman transport to quantify its intra-annual variability. The year-long average overturning is 18.7 � 5.6 sverdrups (Sv) (range: 4.0 to 34.9 Sv, where 1 Sv = a flow of ocean water of 10⁶ cubic meters per second). Interannual changes in the overturning can be monitored with a resolution of 1.5 Sv.

Dong, S., S.T. Gille, and J. Sprintall. An assessment of the Southern Ocean mixed layer heat budget. Journal of Climate, 20(17):4425-4442 (2007).

The mixed layer heat balance in the Southern Ocean is examined by combining remotely sensed measurements and in situ observations from 1 June 2002 to 31 May 2006, coinciding with the period during which Advanced Microwave Scanning Radiometer-Earth Observing System (EOS) (AMSR-E) sea surface temperature measurements are available. Temperature/salinity profiles from Argo floats are used to derive the mixed layer depth. All terms in the heat budget are estimated directly from available data. The domain-averaged terms of oceanic heat advection, entrainment, diffusion, and air-sea flux are largely consistent with the evolution of the mixed layer temperature. The mixed layer temperature undergoes a strong seasonal cycle, which is largely attributed to the air-sea heat fluxes. Entrainment plays a secondary role. Oceanic advection also experiences a seasonal cycle, although it is relatively weak. Most of the seasonal variations in the advection term come from the Ekman advection, in contrast with western boundary current regions where geostrophic advection controls the total advection. Substantial imbalances exist in the regional heat budgets, especially near the northern boundary of the Antarctic Circumpolar Current. The biggest contributor to the surface heat budget error is thought to be the air-sea heat fluxes, because only limited Southern Hemisphere data are available for the reanalysis products and, hence, these fluxes have large uncertainties. In particular, the lack of in situ measurements during winter is of fundamental concern. Sensitivity tests suggest that a proper representation of the mixed layer depth is important to close the budget. Salinity influences the stratification in the Southern Ocean; temperature alone provides an imperfect estimate of mixed layer depth and, because of this, also an imperfect estimate of the temperature of water entrained into the mixed layer from below.

Dong, S., S.L. Hautala, and K.A. Kelly. Interannual variations in upper-ocean heat content and heat transport convergence in the western North Atlantic. Journal of Physical Oceanography, 37(11):2682-2697 (2007).

Subsurface temperature data in the western North Atlantic Ocean are analyzed to study the variations in the heat content above a fixed isotherm and contributions from surface heat fluxes and oceanic processes. The study region is chosen based on the data density; its northern boundary shifts with the Gulf Stream position, and its southern boundary shifts to contain constant volume. The temperature profiles are objectively mapped to a uniform grid (0.5� latitude and longitude, 10 m in depth, and 3 months in time). The interannual variations in upper-ocean heat content show good agreement with the changes in the sea surface height from the Ocean Topography Experiment (TOPEX)/Poseidon altimeter; both indicate positive anomalies in 1994 and 1998-99 and negative anomalies in 1996-97. The interannual variations in surface heat fluxes cannot explain the changes in upper-ocean heat storage rate. On the contrary, a positive anomaly in heat released to the atmosphere corresponds to a positive upper-ocean heat content anomaly. The oceanic heat transport, mainly owing to the geostrophic advection, controls the interannual variations in heat storage rate, which suggests that geostrophic advection plays an important role in the air-sea heat exchange. The 18�C isotherm depth and layer thickness also show good correspondence to the upper-ocean heat content; a deep and thin 18�C layer corresponds to a positive heat content anomaly. The oceanic transport in each isotherm layer shows an annual cycle, converging heat in winter, and diverging in summer in a warm layer; it also shows interannual variations with the largest heat convergence occurring in even warmer layers during the period of large ocean-to-atmosphere flux.

Dorst, N.M. The National Hurricane Research Project: 50 years of research, rough rides, and name changes. Bulletin of the American Meteorological Society, 88(10):1566-1588 (2007).

After the disastrous Atlantic hurricane season of 1954, the Weather Bureau created the National Hurricane Research Project (NHRP) to advance tropical cyclone science and improve forecasts. In the late 1950s, NHRP pioneered quantitative observations with instrumented aircraft and shaped the modern understanding of tropical cyclones. By the early 1960s, it was intimately involved in Project STORMFURY, the U.S. Government's hurricane modification program. During this time, it was collocated with the Miami, Florida, hurricane forecast office, and became a permanent laboratory. Its scientists became involved in international experiments and collaborated with researchers from around the world. In the 1970s, its theoretical and computer modeling work advanced, supporting STORMFURY. The project required the acquisition of new aircraft. Ironically, the improved instrumentation led to the dissolution of STORMFURY in 1983. Researchers found new avenues of investigation, including hurricane climatology, synoptic flow interaction, tropical cyclone dynamics, and improving intensity forecasts.

Dorst, N.M., and E. Rule. Fifty years of NOAA hurricane research. Mariners Weather Log, 51(1):10-13 (2007).

For over 50 years, NOAA scientists have applied theoretical studies and computer models and have flown aircraft into hurricanes, all to better understand what makes these storms tick. This research has resulted in a much deeper scientific understanding of hurricanes and improved NOAA hurricane forecasts.

Drennen, W.M., J.A. Zhang, J.F. French, C. McCormick, and P.G. Black. Turbulent fluxes in the hurricane boundary layer, Part II: Latent heat flux. Journal of the Atmospheric Sciences, 64(4):1103-1115 (2007).

As part of the recent ONR-sponsored Coupled Boundary Layer Air-Sea Transfer (CBLAST) Departmental Research Initiative, an aircraft was instrumented to carry out direct turbulent flux measurements in the high wind boundary layer of a hurricane. During the 2003 field season flux measurements were made during Hurricanes Fabian and Isabel. Here the first direct measurements of latent heat fluxes measured in the hurricane boundary layer are reported. The previous wind speed range for humidity fluxes and Dalton numbers has been extended by over 50%. Up to 30 m s^-1, the highest 10-m winds measured, the Dalton number is not significantly different from the Humidity Exchange over the Sea (HEXOS) result, with no evidence of an increase with wind speed.

Dye, J.E., M.G. Bateman, H.J. Christian, E. Defer, C.A. Grainger, W.D. Hall, E.P. Krider, S.A. Lewis, D.M. Mach, F.J. Merceret, J.C. Willett, and P.T. Willis. Electric fields, cloud microphysics, and reflectivity in anvils of Florida thunderstorms. Journal of Geophysical Research, 112(D11):D11215, doi:10.1029/2006JD007550 (2007).

A coordinated aircraft-radar project that investigated the electric fields, cloud microphysics, and radar reflectivity of thunderstorm anvils near Kennedy Space Center is described. Measurements from two cases illustrate the extensive nature of the microphysics and electric field observations. As the aircraft flew from the edges of anvils into the interior, electric fields very frequently increased abruptly from ~1 to >10 kV m¹ even though the particle concentrations and radar reflectivity increased smoothly. The abrupt increase in field usually occurred when the aircraft entered regions with a reflectivity of 10-15 dBZ. We suggest that the abrupt increase in electric field was because the charge advection from the convective core did not occur across the entire breadth of the anvil and because the advection of charge was not constant in time. Also, some long-lived anvils showed enhancement of electric field and reflectivity far downwind of the convective core. Screening layers were not detected near the edges of the anvils. Comparisons of electric field magnitude with particle concentration or reflectivity for a combined data set that included all anvil measurements showed a threshold behavior. When the average reflectivity, such as in a 3-km cube, was less than approximately 5 dBZ, the electric field magnitude was <3 kV m¹. Based on these findings, the Volume Averaged Height Integrated Radar Reflectivity (VAHIRR) is now being used by the NASA, the Air Force, the and Federal Aviation Administration in new Lightning Launch Commit Criteria as a diagnostic for high electric fields in anvils.

French, J.F., W.M. Drennan, J.A. Zhang, and P.G. Black. Turbulent fluxes in the hurricane boundary layer, Part I: Momentum flux. Journal of the Atmospheric Sciences, 64(4):1089-1102 (2007).

An important outcome from the ONR-sponsored Coupled Boundary Layer Air-Sea Transfer (CBLAST) Hurricane Program is the first-ever direct measurements of momentum flux from within hurricane boundary layers. In 2003, a specially instrumented NOAA P3 aircraft obtained measurements suitable for computing surface wind stress and ultimately estimating drag coefficients in regions with surface wind between 18 and 30 m s^-1. Analyses of data are presented from 48 flux legs flown within 400 m of the surface in two storms. Results suggest a roll-off in the drag coefficient at higher wind speeds, in qualitative agreement with laboratory and modeling studies and inferences of drag coefficients using a log-profile method. However, the amount of roll-off and the wind speed at which the roll-off occurs remains uncertain, underscoring the need for additional measurements.

Garzoli, S.L., and M.O. Baringer. Meridional heat transport determined with expendable bathythermographs, Part II: South Atlantic transport. Deep-Sea Research, Part I, 54(8):1402-1420 (2007).

Fourteen temperature sections collected between July 2002 and May 2006 are analyzed to obtain estimates of the meridional heat transport variability of the South Atlantic Ocean. The methodology proposed in Part I is used to calculate the heat transport from temperature data obtained from high-density XBT profiles taken along transects from Cape Town, South Africa to Buenos Aires, Argentina. Salinity is estimated from Argo profiles and CTD casts for each XBT temperature observation using statistical relationships between temperature, latitude, longitude, and salinity computed along constant-depth surfaces. Full-depth temperature/salinity profiles are obtained by extending the profiles to the bottom of the ocean using deep climatological data. The meridional transport is then determined by using the standard geostrophic method, applying NCEP-derived Ekman transports, and requiring that salt flux through the Bering Straits be conserved. The results from the analysis indicate a mean meridional heat transport of 0.54 PW (PW=10¹⁵ Watts) with a standard deviation of 0.11 PW. The geostrophic component of the heat flux has a marked annual cycle following the variability of the Brazil Malvinas Confluence Front, and the geostrophic annual cycle is 180° out of phase with the annual cycle observed in the Ekman fluxes. As a result, the total heat flux shows significant interannual variability with only a small annual cycle. Uncertainties due to different wind products and locations of the sections are independent of the methodology used.

Halverson, J., M.L. Black, S. Braun, D. Cecil, M. Goodman, A. Heymsfield, G. Heymsfield, R. Hood, T. Krishnamurti, G. McFarquhar, M.J. Mahoney, J. Molinari, R.F. Rogers, J. Turk, C. Velden, D.-L. Zhang, E. Zipser, and R. Kakar. NASA's Tropical Cloud Systems and Processes (TCSP) Experiment: Investigating tropical cyclogenesis and hurricane intensity change. Bulletin of the American Meteorological Society, 88(6):867-882 (2007).

In July 2005, the National Aeronautics and Space Administration investigated tropical cyclogenesis, hurricane structure, and intensity change in the eastern North Pacific and western Atlantic using its ER-2 high-altitude research aircraft. The campaign, called the Tropical Cloud Systems and Processes (TCSP) experiment, was conducted in conjunction with the National Oceanic and Atmospheric Administration/ Hurricane Research Division's Intensity Forecasting Experiment. A number of in situ and remote sensor datasets were collected inside and above four tropical cyclones representing a broad spectrum of tropical cyclone intensity and development in diverse environments. While the TCSP datasets directly address several key hypotheses governing tropical cyclone formation, including the role of vertical wind shear, dynamics of convective bursts, and upscale growth of the initial vortex, two of the storms sampled were also unusually strong, early season storms. Highlights from the genesis missions are described in this article, along with some of the unexpected results from the campaign. Interesting observations include an extremely intense, highly electrified convective tower in the eyewall of Hurricane Emily and a broad region of mesoscale subsidence detected in the lower stratosphere over landfalling Tropical Storm Gert.

Hendee, J.C. The integrated coral observing network. Earth System Monitor, 15(4):10 (2007).

No abstract.

Huang, X.-L., Y. Chen, and M. Shenker. Solid phosphorus phases in aluminum- and iron-treated biosolids. Journal of Environmental Quality, 36(2):549-556 (2007).

Stabilization of phosphorus (P) in sewage sludge (biosolids) to reduce water-soluble P concentrations is essential for minimizing P loss from amended soils and maximizing the capacity of the soil to safely serve as an outlet for this waste material. The chemical form at which P is retained in biosolids stabilized by Al2(SO4)3�18H2O (alum) or FeSO4�7H2O (FeSul) was investigated by scanning electron microscopy (SEM) equipped with energy-dispersive X-ray elemental spectrometry (EDXS) and by X-ray diffraction (XRD). Both treatments resulted in the formation of a Ca-P phase, probably brushite. Phosphorus was further retained in the alum-treated biosolids by precipitation of an Al-P phase with an Al/P molar ratio of about 1:1, while in the FeSul-treated biosolids, P was retained by both precipitation with Fe/P molar ratios of 1:1 or 1.5:1, and by adsorption onto newly formed Fe hydroxides exhibiting an Fe/P molar ratio of up to 11:1. All of these mechanisms efficiently reduced P solubility and are crucial in biosolids environmentally safe agronomic beneficial use for this waste product; however, each P phase formed may react differently in the amended soil, depending on soil properties. Thus, the proper P stabilization method would depend on the target soil.

Joiner, J., E. Brin, R. Treadon, J. Derber, P. Van Delst, A. Da Silva, J. Le Marshall, P. Poli, R. Atlas, D. Bungato, and C. Cruz. Effects of data selection and error specification on the assimilation of AIRS data. Quarterly Journal of the Royal Meteorological Society, 133(622):181-196 (2007).

The Atmospheric InfraRed Sounder (AIRS), flying aboard NASA's Aqua satellite with the Advanced Microwave Sounding Unit-A (AMSU-A) and four other instruments, has been providing data for use in numerical weather prediction and data assimilation systems for over three years. The full AIRS data set is currently not transmitted in near-real time to the prediction/assimilation centres. Instead, data sets with reduced spatial and spectral information are produced and made available within three hours of the observation time. In this paper, we evaluate the use of different channel selections and error specifications. We achieve significant positive impact from the Aqua AIRS/AMSU-A combination during our experimental time period of January 2003. The best results are obtained using a set of 156 channels that do not include any in the H₂O band between 1080 and 2100 cm^-1. The H₂O band channels have a large influence on both temperature and humidity analyses. If observation and background errors are not properly specified, the partitioning of temperature and humidity information from these channels will not be correct, and this can lead to a degradation in forecast skill. Therefore, we suggest that it is important to focus on background error specification in order to maximize the impact from AIRS and similar instruments. In addition, we find that changing the specified channel errors has a significant effect on the amount of data that enters the analysis as a result of quality control thresholds that are related to the errors. However, moderate changes to the channel errors do not significantly impact forecast skill with the 156 channel set. We also examine the effects of different types of spatial data reduction on assimilated data sets and NWP forecast skill. Whether we pick the centre or the warmest AIRS pixel in a 3×3 array affects the amount of data ingested by the analysis but does not have a statistically significant impact on the forecast skill.

Jones, TA., D.J. Cecil, and J.P. Dunion. The environmental and inner-core conditions governing the intensity of Hurricane Erin (2001). Weather and Forecasting, 22(4):708-725 (2007).

The evolution of Hurricane Erin (2001) is presented from the perspective of its environmental and inner-core conditions, particularly as they are characterized in the Statistical Hurricane Intensity Prediction Scheme with Microwave Imagery (SHIPS-MI). Erin can be described as having two very distinct periods. The first, which occurred between 1 and 6 September 2001, was characterized by a struggling tropical storm failing to intensify as the result of unfavorable environmental and inner-core conditions. The surrounding environment during this period was dominated by moderate shear and mid- to upper-level dry air, both caused in some part by the presence of a Saharan air layer (SAL). Further intensification was inhibited by the lack of sustained deep convection and latent heating near the low-level center. The authors attribute this in part to negative effects from the SAL. The thermodynamic conditions associated with the SAL were not well sampled by the SHIPS parameters, resulting in substantial overforecasting by both SHIPS and SHIPS-MI. Instead, the hostile conditions surrounding Erin caused its dissipation on 6 September. The second period began on 7 September when Erin re-formed north of the original center. Erin began to pull away from the SAL and moved over 29�C sea surface temperatures, beginning a rapid intensification phase and reaching 105 kt by 1800 UTC 9 September. SHIPS-MI forecasts called for substantial intensification as in the previous period, but this time the model underestimated the rate of intensification. The addition of inner-core characteristics from passive microwave data improved the skill somewhat compared to SHIPS, but still left much room for improvement. For this period, it appears that the increasingly favorable atmospheric conditions caused by Erin moving away from the SAL were not well sampled by SHIPS or SHIPS-MI. As a result, the intensity change forecasts were not able to take into account the more favorable environment.

Jurado, J.L., G.L. Hitchcock, and P.B. Ortner. Seasonal variability of nutrient and phytoplankton distributions on the southwest Florida inner shelf. Bulletin of Marine Science, 80(1):21-43 (2007).

Surface nutrient concentrations and phytoplankton biomass were monitored on the southwest Florida inner shelf during two years of contrasting rainfall (1999-2000) to assess potential linkages between freshwater discharge and surface phytoplankton communities. A diatom bloom began between April and June each year near Cape Sable during the period of peak freshwater discharge and maximum annual nutrient flux from the Shark River watershed. The bloom began as netplankton biomass (>5 µm size-fraction Chl a) and increased following an increase in discharge from the Shark River. Maximum phytoplankton biomass occurred in October when Rhizolosenia spp. dominated the netplankton community, and the annual maximum occurred in biogenic silica (BSiO₂) concentrations, at 10 and 20 µmol L^-1 in 1999 and 2000, respectively. Results suggest riverine discharge onto the southwest Florida inner shelf is an important nutrient source that influences the timing and distribution of annual diatom blooms. Although particulate matter composition suggests nitrogen potentially limits phytoplankton biomass during most of the year, the diatom community may be limited by silicon availability at bloom termination.

Kanzow, T., S.A. Cunningham, D. Rayner, J.J.-M. Hirschi, W.E. Johns, M.O. Baringer, H.L. Bryden, L.M. Beal, C.S. Meinen, and J. Marotzke. Observed flow compensation associated with the MOC at 26.5�N in the Atlantic. Science, 317(5840):938-941 (2007).

The Atlantic meridional overturning circulation (MOC), which provides one-quarter of the global meridional heat transport, is composed of a number of separate flow components. How changes in the strength of each of those components may affect that of the others has been unclear because of a lack of adequate data. We continuously observed the MOC at 26.5�N for 1 year using end-point measurements of density, bottom pressure, and ocean currents; cable measurements across the Straits of Florida; and wind stress. The different transport components largely compensate for each other, thus confirming the validity of our monitoring approach. The MOC varied over the period of observation by �5.7 x 10⁶ cubic meters per second, with density-inferred and wind-driven transports contributing equally to it. We find evidence for depth-independent compensation for the wind-driven surface flow.

Kelble, C.R., E.M. Johns, W.K. Nuttle, T.N. Lee, R.H. Smith, and P.B. Ortner. Salinity patterns of Florida Bay. Estuarine, Coastal, and Shelf Science, 71(1-2):318-334 (2007).

The salinity of Florida Bay has undergone dramatic changes over the past century. Salinity values reached their most extreme, up to 70, in the late 1980s, concurrent with ecological changes in Florida Bay including a mass seagrass die-off. In this study, surface salinity was measured at approximately monthly intervals between 1998 and 2004. The 7-year data set was analyzed to quantify the effects of precipitation, runoff, evaporation, and climatic variability on salinity in Florida Bay. Overall mean Bay-wide salinity varied from a low of 24.2 just after the passing of Hurricane Irene in October 1999 to a high of 41.8 near the end of a drought period in July 2001. Bay-wide mean salinity exhibited dramatic decreases, up to -0.5 per day, whereas increases were slower, with a maximum rate of 0.1 per day. The freshwater budget for Florida Bay was slightly negative on an annual basis with significant positive monthly values observed during the peak of the rainy season (August through October) and significant negative monthly values observed during the peak of the dry season (March through May). This resulted in a minimum mean monthly Bay-wide salinity in January and a maximum monthly mean in July. Mean salinity for the overall Bay and for each of its four sub-regions could be predicted with reasonable accuracy utilizing a mass balance box model. There was no monotonic trend in salinity over this 7-year study; however, meteorological phenomena, such as tropical cyclones and El Ni�o-Southern Oscillation, dramatically altered the salinity patterns of Florida Bay on interannual time scales.

LaGier, M.J., J.W. Fell, and K.D. Goodwin. Electrochemical detection of harmful algae and other microbial contaminants in coastal waters using hand-held biosensors. Marine Pollution Bulletin, 54(6):757-770 (2007).

Standard methods to identify microbial contaminants in the environment are slow, laborious, and can require specialized expertise. This study investigated electrochemical detection of microbial contaminants using commercially available, hand-held instruments. Electrochemical assays were developed for a red tide dinoflagellate (Karenia brevis), fecal-indicating bacteria (Enterococcus spp.), markers indicative of human sources of fecal pollution (human cluster Bacteroides and the esp gene of Enterococcus faecium), bacterial pathogens (Escherichia coli 0157:H7, Salmonella spp., Campylobacter jejuni, Staphylococcus aureus), and a viral pathogen (adenovirus). For K. brevis, two assay formats (Rapid PCR-Detect and Hybrid PCR-Detect) were tested and both provided detection limits of 10 genome equivalents for DNA isolated from K. brevis culture and amplified by PCR. Sensitivity with coastal water samples was sufficient to detect K. brevis that was "present" (< 1000 cells/l) without yielding false positive results and the electrochemical signal was significantly different than for samples containing cells at "medium" concentrations (100,000 to <10⁶ cells/l). Detection of K. brevis RNA was also shown. Multi-target capability was demonstrated with an 8-plex assay for bacterial and viral targets using isolated DNA, natural beach water spiked with human feces, and water and sediments collected from New Orleans, Louisiana following Hurricane Katrina. Furthermore, direct detection of dinoflagellate and bacterial DNA was achieved using lysed cells rather than extracted nucleic acids, allowing streamlining of the process. The methods presented can be used to rapidly (3-5 h) screen environmental water samples for the presence of microbial contaminants and have the potential to be integrated into semi-automated detection platforms.

Lee, S.-K., D.B. Enfield, and C. Wang. What drives the seasonal onset and decay of the western hemisphere warm pool? Journal of Climate, 20(10):2133-2146 (2007).

The annual heat budget of the Western Hemisphere warm pool (WHWP) is explored using the output of an ocean general circulation model (OGCM) simulation. According to the analysis, the WHWP cannot be considered as a monolithic whole with a single set of dominating processes that explain its behavior. The three regions considered, namely the eastern north Pacific (ENP), the Gulf of Mexico (GoM), and the Caribbean Sea (CBN), are each unique in terms of the atmospheric and oceanic processes that dominate the corresponding heat budgets. In the ENP region, clear-sky shortwave radiation flux is responsible for the growth of the warm pool in boreal spring, while increased cloud cover in boreal summer and associated reduction in solar radiation play a crucial role for the ENP warm pool's demise. Ocean upwelling in the Costa Rica Dome connected to surrounding areas by horizontal advection offers a persistent yearlong cooling mechanism. Over the Atlantic, the clear-sky radiation flux that increases monotonically from December to May and decreases later is largely responsible for the onset and decay of the Atlantic-side warm pool in boreal summer and fall. The CBN region is affected by upwelling and horizontal advective cooling within and away from the coastal upwelling zone off northern South America during the onset and peak phases, thus slowing down the warm pool's development, but no evidence was found that advective heat flux divergence is important in the GoM region. Turbulent mixing is also an important cooling mechanism in the annual cycle of the WHWP, and the vertical shear at the warm pool base helps to sustain the turbulent mixing. Common to all three WHWP regions is the reduction of wind speed at the peak phase, suggestive of a convection-evaporation feedback known to be important in the Indo-Pacific warm pool dynamics.

Lee, T.N., E. Johns, and P.B. Ortner. Physical processes, pp. 30-54. In Florida Bay Science Program: A Synthesis of Research on Florida Bay, J. Hunt and W. Nuttle (eds.). Fish and Wildlife Research Institute, FWRI Technical Report, TR-11, 148 pp. (2007).

No abstract.

Li, T., C.-Y. She, H.-L. Liu, and M.T. Montgomery. Evidence of a gravity wave breaking event and the estimation of the wave characteristics from sodium lidar observation over Fort Collins, Colorado (41�N, 105�W). Geophysical Research Letters, 34(5):L05815, doi:10.1029/2006GL028988 (2007).

On the night of December 3rd, 2004 (UT day 338), we observed a significant acceleration of horizontal wind near 100 km between 0900 and 0915 UT accompanied by a temperature cooling at the same altitude and warming below it. The Lomb spectrum analysis of the raw dataset revealed that a gravity wave with 1.5 hr period was significant between 0500 and 0900 UT, but blurred after 0900 UT, suggesting the transfer of wave energy and momentum from wave field to mean flow. Most likely, this observed phenomenon is due to the breaking of an upward propagating gravity wave with an apparent period of ~1.5 hr. Using linear saturation theory and assuming a monochromatic wave packet, we estimated the characteristics of breaking gravity wave, eddy diffusion coefficient, and a simple relation between Prandtl number and turbulence localization measure when the wave is breaking, from the experimentally determined heating rate, horizontal wind acceleration, and background temperature and winds.

Lillibridge, J., N. Shay, M. DeMaria, G. Goni, M. Mainelli, R. Scharroo, and L. Russell. Hurricane intensity forecasting at NOAA using ENVISAT altimetry. Proceeding, Envisat Symposium 2007, Montreaux, Switzerland, April 23-27, 2007. European Space Agency, SP-636 (CD-ROM), 7 pp. (2007).

NOAA's National Hurricane Center (NHC) has a number of skillful track guidance models, but only a limited number of intensity prediction schemes. The relatively low skill of intensity forecasts is due to the complexity of the problem, which involves a very wide range of scales, and interaction with the underlying ocean. The empirical Statistical Hurricane Intensity Prediction Scheme (SHIPS) provides intensity predictions with accuracy comparable to those from the coupled three-dimensional GFDL hurricane model. SHIPS was implemented at NHC in 1996, and upgraded in 2004 to include upper ocean heat content (OHC) estimated from satellite altimetry. It is believed that hurricane intensification can occur over regions where OHC values exceed 50 kJ/cm², not just in regions of high sea surface temperature. The OHC analysis presently incorporates sea surface height from Jason-1 and Geosat Follow-On. Envisat altimetry is expected to be included in the OHC analysis for the 2007 hurricane season. Efforts are underway to reduce the latency of Envisat data by including the Fast-Delivery Marine Abridged Record (FDMAR) products.

Lonfat, M., R.F. Rogers, T. Marchok, and F.D. Marks. A parametric model for predicting hurricane landfall. Monthly Weather Review, 135(9):3086-3097 (2007).

This study documents a new parametric hurricane rainfall prediction scheme, based on the rainfall climatology and persistence model (R-CLIPER) used operationally in the Atlantic Ocean basin to forecast rainfall accumulations. Although R-CLIPER has shown skill at estimating the mean amplitude of rainfall across the storm track, one underlying limitation is that it assumes that hurricanes produce rain fields that are azimuthally symmetric. The new implementations described here take into account the effect of shear and topography on the rainfall distribution through the use of parametric representations of these processes. Shear affects the hurricane rainfall by introducing spatial asymmetries, which can be reasonably well modeled to first order using a Fourier decomposition. The effect of topography is modeled by evaluating changes in elevation of flow parcels within the storm circulation between time steps and correcting the rainfall field in proportion to those changes. Effects modeled in R-CLIPER and those from shear and topography are combined in a new model called the Parametric Hurricane Rainfall Model (PHRaM). Comparisons of rainfall accumulations predicted from the operational R-CLIPER model, PHRaM, and radar-derived observations show some improvement in the spatial distribution and amplitude of rainfall when shear is accounted for and significant improvements when both shear and topography are modeled.

Lumpkin, R. Water movement and circulation. In Hidden Depths: Atlas of the Oceans, A.E. Theberge (ed.). Collins Publishers (ISBN: 9780061345142), 50-63 (2007).

No abstract.

Lumpkin, R., and G.J. Goni. Global oceans: Surface current observations. In State of the Climate in 2006, A. Arguez, A.M. Waple, and A.M. Sanchez-Lugo (eds.). Bulletin of the American Meteorological Society, 88(6):S36-S37 (2007).

No abstract.

Lumpkin, R., and M.C. Pazos. Measuring surface currents with Surface Velocity Program drifters: The instrument, its data, and some recent results. In Lagrangian Analysis and Prediction of Coastal and Ocean Dynamics, A. Griffa, A.D. Kirwan, A.J. Mariano, T. Ozgokmen, and H.T. Rossby (eds.). Cambridge University Press, 39-67 (2007).

No abstract.

Lumpkin, R., and K. Speer. Global ocean meridional overturning. Journal of Physical Oceanography, 37(10):2550-2562 (2007).

A decade-mean global ocean circulation is estimated using inverse techniques, incorporating air-sea fluxes of heat and freshwater, recent hydrographic sections, and direct current measurements. This information is used to determine mass, heat, freshwater, and other chemical transports, and to constrain boundary currents and dense overflows. The 18 boxes defined by these sections are divided into 45 isopycnal (neutral density) layers. Diapycnal transfers within the boxes are allowed, representing advective fluxes and mixing processes. Air-sea fluxes at the surface produce transfers between outcropping layers. The model obtains a global overturning circulation consistent with the various observations, revealing two global-scale meridional circulation cells: an upper cell, with sinking in the Arctic and subarctic regions and upwelling in the Southern Ocean, and a lower cell, with sinking around the Antarctic continent and abyssal upwelling mainly below the crests of the major bathymetric ridges.

Manzello, D.P., R. Berkelmans, and J.C. Hendee. Coral bleaching indices and thresholds for the Florida Reef Tract, Bahamas, and St. Croix, U.S. Virgin Islands. Marine Pollution Bulletin, 54(12):1923-1931 (2007).

It is well established that elevated sea temperatures cause widespread coral bleaching, yet confusion lingers as to what facet of extreme temperatures is most important. Utilizing long-term in situ datasets, we calculated nine thermal stress indices and tested their effectiveness at segregating bleaching years a posteriori for multiple reefs on the Florida Reef Tract. The indices examined represent three aspects of thermal stress: (1) short-term, acute temperature stress; (2) cumulative temperature stress; and (3) temperature variability. Maximum monthly sea surface temperature (SST) and the number of days >30.5�C were the most significant; indicating that cumulative exposure to temperature extremes characterized bleaching years. Bleaching thresholds were warmer for Florida than the Bahamas and St. Croix, U.S. Virgin Islands reflecting differences in seasonal maximum SST. Hindcasts showed that monthly mean SST above a local threshold explained all bleaching years in Florida, the Bahamas, and U.S. Virgin Islands.

Manzello, D.P., M. Brandt, T.B. Smith, D. Lirman, J.C. Hendee, and R.S. Nemeth. Hurricanes benefit bleached corals. Proceedings of the National Academy of Sciences, 104(29):12,035-12,039 (2007).

Recent, global mass-mortalities of reef corals due to record warm sea temperatures have led researchers to consider global warming as one of the most significant threats to the persistence of coral reef ecosystems. The passage of a hurricane can alleviate thermal stress on coral reefs, highlighting the potential for hurricane associated cooling to mitigate climate change impacts. We provide evidence that hurricane-induced cooling was responsible for the documented differences in the extent and recovery time of coral bleaching between the Florida Reef Tract and the U.S. Virgin Islands during the Caribbean-wide 2005 bleaching event. These results are the only known scenario where the effects of a hurricane can benefit a stressed marine community.

Marchok, T.P., R.F. Rogers, and R.E. Tuleya. Validation schemes for tropical cyclone quantitative precipitation forecasts: Evaluation of operational models for U.S. landfalling cases. Weather and Forecasting, 22(4):726-746 (2007).

A scheme for validating quantitative precipitation forecasts (QPFs) for landfalling tropical cyclones is developed and presented here. This scheme takes advantage of the unique characteristics of tropical cyclone rainfall by evaluating the skill of rainfall forecasts in three attributes: the ability to match observed rainfall patterns, the ability to match the mean value and volume of observed rainfall, and the ability to produce the extreme amounts often observed in tropical cyclones. For some of these characteristics, track-relative analyses are employed that help to reduce the impact of model track forecast error on QPF skill. These characteristics are evaluated for storm-total rainfall forecasts of all U.S. landfalling tropical cyclones from 1998 to 2004 by the NCEP operational models, that is, the Global Forecast System (GFS), the Geophysical Fluid Dynamics Laboratory (GFDL) hurricane model, and the North American Mesoscale (NAM) model, as well as the benchmark Rainfall Climatology and Persistence (R-CLIPER) model. Compared to R-CLIPER, all of the numerical models showed comparable or greater skill for all of the attributes. The GFS performed the best of all of the models for each of the categories. The GFDL had a bias of predicting too much heavy rain, especially in the core of the tropical cyclones, while the NAM predicted too little of the heavy rain. The R-CLIPER performed well near the track of the core, but it predicted much too little rain at large distances from the track. Whereas a primary determinant of tropical cyclone QPF errors is track forecast error, possible physical causes of track-relative differences lie with the physical parameterizations and initialization schemes for each of the models. This validation scheme can be used to identify model limitations and biases and guide future efforts toward model development and improvement.

Marks, F.D. Recent results from NOAA's hurricane Intensity Forecast Experiment (IFEX). Preprints, 11th Symposium on Integrated Observing and Assimilation Systems for the Atmosphere, Oceans, and Land Surface (IOAS-AOLS), San Antonio, TX, January 14-18, 2007. American Meteorological Society, Boston, CD-ROM, 6 pp. (2007).

No abstract.

McGillis, W.R., J.H. Dacey, J.D. Ware, D.T. Ho, J.T. Bent, W.E. Asher, C.J. Zappa, P.A. Raymond, R. Wanninkhof, and S. Komori. Air-water reconciliation between the atmospheric CO₂ profile and mass balance techniques. In Transport at the Air-Sea Interface: Measurements, Models, and Parameterizations, C.S. Garbe, R.A. Handler, and B. Jahne (eds.). Springer-Verlag, Berlin, 181-192 (2007).

Studies deploying atmospheric flux-profile techniques in laboratory wind-wave tanks have been performed to demonstrate and verify the use of air-side turbulent transport models and micrometeorological approaches to accurately determine air-water gas transfer velocities. Air-water gas transfer velocities have been estimated using the CO₂ atmospheric flux-profile technique in laboratory wind-wave tanks both at the NASA Wallops Flight Facility, USA and Kyoto University, Japan. Gas fluxes using the flux-profile and the waterside mass balance techniques have been reconciled. Air-water fluxes of H₂O and momentum were also measured simultaneously in a linear wind-wave tank. The waterside mass balances used the evasion of SF₆. The CO₂, H₂O, and momentum fluxes were calculated using the atmospheric flux-profile technique over a wind speed range of 1 to 14 m s^-1. The CO₂ and H₂O atmospheric profile model uses airside turbulent diffusivities derived from momentum fluxes. These studies demonstrate that the quantification of air-water CO₂ fluxes using the atmospheric flux-profile technique can be implemented in the laboratory. The profile technique can be used to measure an air-water flux in much less time than a mass balance. Effects of surfactants, wind speed, and wind stress on air-water transfer are also explored using the flux-profile technique. Validation of the air-water CO₂ gas exchange in laboratory wind-wave tanks provides evidence and support that this technique may be used in field studies.

Mestas-Nunez, A.M., D.B. Enfield, and C. Zhang. Water vapor fluxes over the Intra-Americas Sea: Seasonal and interannual variability and associations with rainfall. Journal of Climate, 20(9):1910-1922 (2007).

The seasonal and interannual variability of moisture transports over the Intra-Americas Sea (including the Gulf of Mexico and the Caribbean Sea) is evaluated using the NCEP-NCAR global reanalysis. The seasonal variability of these moisture transports is consistent with previous studies and shows distinctive winter and summer regimes. Boreal winter moisture is mainly delivered to the central United States from the Pacific with some contribution from the Gulf of Mexico. It is during the boreal summer that the moisture flow over the Intra-Americas Sea is most effective in supplying the water vapor to the central United States via the northern branch of the Caribbean low-level jet. The increase of intensity of this jet during July is associated with an increase in evaporation over the Intra-Americas Sea, consistent with midsummer drought conditions over this region. During both summer and winter, the interannual variability of the inflow of moisture from the Intra-Americas Sea into central United States is associated with Caribbean low-level jet variability. The source of the varying moisture is mainly the Gulf of Mexico and the North Atlantic area just east of the Bahamas Islands and the sink is precipitation over east-central United States. The main teleconnection pattern for these interannual variations appears to be the Pacific-North American, although in boreal winter ENSO and possibly the North Atlantic Oscillation may also play a role. During boreal summer, associations with ENSO mainly involve the zonal moisture exchange between the Intra-Americas Sea/tropical Atlantic and the tropical Pacific.

Moyer, A.C., J.L. Evans, and M.D. Powell. Comparison of observed gale radius statistics. Meteorology and Atmospheric Physics, 97(1-4):41-55 (2007).

Forecasts of tropical cyclone track and intensity have long been used to characterize the evolution and expected threat from a tropical storm. However, in recent years, recognition of the contributions of subtropical cyclogenesis to tropical storm formation and the process of extratropical transition to latter stages of the once-tropical storm's lifecycle have raised awareness about the importance of storm structure. Indeed, the structure of a cyclone determines the distribution and intensity of the significant weather associated with that storm. In this study, storm structure is characterized in terms of significant wind radii. The radii of tropical storm, damaging, and hurricane-force winds, as well as the radius of maximum winds are all analyzed. These wind radii are objectively derived from the H*Wind surface wind analysis system. Initially, six years of these data are examined for consistency with previous studies. Having ascertained that the H*Wind radii are realistic, detailed comparisons are performed between the H*Wind and NHC Best Track wind radii for two years (2004 and 2005) of North Atlantic tropical storm and hurricane cases. This intercomparison reveals an unexpected bias: the H*Wind radii are consistently larger than the NHC Best Track for all but the smallest and least intense storms. Further examination of the objectively-determined H*Wind tropical storm force wind radius data compared to subjectively-determined radii for the same storm times demonstrates that the objective wind radii are underestimating the extent of the tropical storm force wind area. Since the objective H*Wind radii are large compared to the NHC Best Track - and yet underestimate the area of tropical storm force winds - this argues for further examination of the methods used to ascertain these significant wind radii.

Nacapricha, D., N. Amornthammarong, K. Sereenonchai, P. Anujarawat, and P. Wilairat. Low cost telemetry with PC sound card for chemical analysis applications. Talanta, 71(2):605-609 (2007).

This work describes the development of a telemetric system in conjunction with a computer sound card for recording of signals. For signal transmission, a transmission wireless microphone was utilized, making the telemeter compatible with the sound card normally equipped inside a personal computer. The developed telemeter is a low-cost apparatus capable of remote monitoring. With the sampling rate of 10 Hz, 100% accuracy was obtained up to a distance of 30 m. The precision was good (% RSD = 0.03-0.09), with relatively low noise. The effective signal range was from 0 to 2 V, with approximately 1100 working steps (greater than 10 bit A/D). The telemetric system was shown to be suitable for wireless recording of outputs from spectrophotometer and pH meter. Potential applications in chemical analysis were demonstrated.

Pandya, R.E., D.R. Smith, D.J. Charlevoix, G.M. Fisher, S.T. Murillo, K.A. Murphy, D.M. Stanitski, and T.M. Whittaker. The 15th AMS Education Symposium. Bulletin of the American Meteorological Society, 88(1):83-85 (2007).

No abstract.

Powell, M.D., and T.A. Reinhold. Tropical cyclone destructive potential by integrated kinetic energy. Bulletin of the American Meteorological Society, 88(4):513-526 (2007).

Tropical cyclone damage potential, as currently defined by the Saffir-Simpson scale and the maximum sustained surface wind speed in the storm, fails to consider the area impact of winds likely to force surge and waves or cause particular levels of damage. Integrated kinetic energy represents a framework that captures the physical process of ocean surface stress forcing waves and surge while also taking into account structural wind loading and the spatial coverage of the wind. Integrated kinetic energy was computed from gridded, objectively analyzed surface wind fields of 23 hurricanes representing large and small storms. A wind destructive potential rating was constructed by weighting wind speed threshold contributions to the integrated kinetic energy, based on observed damage in Hurricanes Andrew, Hugo, and Opal. A combined storm surge and wave destructive potential rating was assigned according to the integrated kinetic energy contributed by winds greater than tropical storm force. The ratings are based on the familiar 1-5 range, with continuous fits to allow for storms as weak as 0.1 or as strong as 5.99.

Powell, M.D., and T.A. Reinhold. Reply to comments on "Tropical cyclone destructive potential by integrated kinetic energy." Bulletin of the American Meteorological Society, 88(11):1800-1801 (2007).

No abstract.

Reynolds, C.A., M.S. Peng, S.J. Majumdar, S.D. Aberson, C.H. Bishop, and R. Buizza. Interpretation of adaptive observing guidance for Atlantic tropical cyclones. Monthly Weather Review, 135(12):4006-4029 (2007).

Adaptive observing guidance products for Atlantic tropical cyclones are compared using composite techniques that allow one to quantitatively examine differences in the spatial structures of the guidance maps and relate these differences to the constraints and approximations of the respective techniques. The guidance maps are produced using the ensemble transform Kalman filter (ETKF) based on ensembles from the National Centers for Environmental Prediction and the European Centre for Medium-Range Weather Forecasts (ECMWF), and total-energy singular vectors (TESVs) produced by ECMWF and the Naval Research Laboratory. Systematic structural differences in the guidance products are linked to the fact that TESVs consider the dynamics of perturbation growth only, while the ETKF combines information on perturbation evolution with error statistics from an ensemble-based data assimilation scheme. The impact of constraining the SVs using different estimates of analysis error variance instead of a total-energy norm, in effect bringing the two methods closer together, is also assessed. When the targets are close to the storm, the TESV products are a maximum in an annulus around the storm, whereas the ETKF products are a maximum at the storm location itself. When the targets are remote from the storm, the TESVs almost always indicate targets northwest of the storm, whereas the ETKF targets are more scattered relative to the storm location and often occur over the northern North Atlantic. The ETKF guidance often coincides with locations in which the ensemble-based analysis error variance is large. As the TESV method is not designed to consider spatial differences in the likely analysis errors, it will produce targets over well-observed regions, such as the continental United States. Constraining the SV calculation using analysis error variance values from an operational 3D variational data assimilation system (with stationary, quasi-isotropic background error statistics) results in a modest modulation of the target areas away from the well-observed regions, and a modest reduction of perturbation growth. Constraining the SVs using the ETKF estimate of analysis error variance produces SV targets similar to ETKF targets and results in a significant reduction in perturbation growth, due to the highly localized nature of the analysis error variance estimates. These results illustrate the strong sensitivity of SVs to the norm (and to the analysis error variance estimate used to define it) and confirm that discrepancies between target areas computed using different methods reflect the mathematical and physical differences between the methods themselves.

Rogers, R.F., M.L. Black, S.S. Chen, and R.A. Black. An evaluation of microphysics fields from mesoscale model simulations of tropical cyclones, Part I: Comparisons with observations. Journal of the Atmospheric Sciences, 64(6):1811-1834 (2007).

This study presents a framework for comparing hydrometeor and vertical velocity fields from mesoscale model simulations of tropical cyclones with observations of these fields from a variety of platforms. The framework is based on the Yuter and Houze constant frequency by altitude diagram (CFAD) technique, along with a new hurricane partitioning technique, to compare the statistics of vertical motion and reflectivity fields and hydrometeor concentrations from two datasets: one consisting of airborne radar retrievals and microphysical probe measurements collected from tropical cyclone aircraft flights over many years, and another consisting of cloud-scale (1.67-km grid length) tropical cyclone simulations using the fifth-generation Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model (MM5). Such comparisons of the microphysics fields can identify biases in the simulations that may lead to an identification of deficiencies in the modeling system, such as the formulation of various physical parameterization schemes used in the model. Improvements in these schemes may potentially lead to better forecasts of tropical cyclone intensity and rainfall. In Part I of this study, the evaluation framework is demonstrated by comparing the radar retrievals and probe measurements to MM5 simulations of Hurricanes Bonnie (1998) and Floyd (1999). Comparisons of the statistics from the two datasets show that the model reproduces many of the gross features seen in the observations, though notable differences are evident. The general distribution of vertical motion is similar between the observations and simulations, with the strongest up- and downdrafts making up a small percentage of the overall population in both datasets, but the magnitudes of vertical motion are weaker in the simulations. The model-derived reflectivities are much higher than observed, and correlations between vertical motion and hydrometeor concentration and reflectivity show a much stronger relationship in the model than what is observed. Possible errors in the data processing are discussed as potential sources of differences between the observed and simulated datasets in Part I. In Part II, attention will be focused on using the evaluation framework to investigate the role that different model configurations (i.e., different resolutions and physical parameterizations) play in producing different microphysics fields in the simulation of Hurricane Bonnie. The microphysical and planetary boundary layer parameterization schemes, as well as higher horizontal and vertical resolutions, will be tested in the simulation to identify the extent to which changes in these schemes are reflected in improvements of the statistical comparisons with the observations.

Sabine, C.L., R.A. Feely, and R. Wanninkhof. Global oceans: Global ocean carbon cycle. In State of the Climate in 2006, A. Arguez, A.M. Waple, and A.M. Sanchez-Lugo (eds.). Bulletin of the American Meteorological Society, 88(6):S40-S43 (2007).

No abstract.

Schecter, D.A., and M.T. Montgomery. Waves in a cloudy vortex. Journal of the Atmospheric Sciences, 64(2):314-337 (2007).

This paper derives a system of equations that approximately govern small-amplitude perturbations in a nonprecipitating cloudy vortex. The cloud coverage can be partial or complete. The model is used to examine moist vortex Rossby wave dynamics analytically and computationally. One example shows that clouds can slow the growth of phase-locked counter-propagating vortex Rossby waves in the eyewall of a hurricane-like vortex. Another example shows that clouds can (indirectly) damp discrete vortex Rossby waves that would otherwise grow and excite spiral inertia-gravity wave radiation from a monotonic cyclone at high Rossby number.

Schmid, C., R.L. Molinari, R. Sabina, Y.-H. Daneshzadeh, X. Xia, E. Forteza, and H. Yang. The real-time data management system for Argo profiling float observations. Journal of Atmospheric and Oceanic Technology, 24(9):1608-1628 (2007).

Argo is an internationally coordinated program directed at deploying and maintaining an array of 3000 temperature and salinity profiling floats on a global 3° latitude x 3° longitude grid. Argo floats are deployed from research vessels, merchant ships, and aircraft. After launch they sink to a prescribed pressure level (typically 1000-2000 dbar), where most floats remain for 10 days. The floats then return to the surface, collecting temperature and salinity profiles. At the surface they transmit the data to a satellite and sink again to repeat the cycle. As of 10 August 2006 there are 2489 floats reporting data. The International Argo Data Management Team oversees the development and implementation of the data management protocols of Argo. Two types of data systems are active: real time and delayed mode. The real-time system receives the transmissions from the Argo floats, extracts the data, checks their quality, and makes them available to the users. The objective of the real-time system is to provide Argo profiles to the operational and research community within 24 h of their measurement. This requirement makes it necessary to control the quality of the data automatically. The delayed-mode quality control is directed at a more detailed look at the profiles using statistical methods and scientific review of the data. In this paper, the real-time data processing and quality-control methodology is described in detail. Results of the application of these procedures to Argo profiles are described.

Sereenonchai, K., P. Saetear, N. Amornthammarong, K. Uraisin, P. Wilairat, S. Motomizu, and D. Nacapricha. Membraneless vaporization unit for direct analysis of solid sample. Analytica Chimica Acta, 597(1):157-162 (2007).

A new apparatus, called "membraneless vaporization" (MBL-VP) unit was designed and developed for direct analysis of solid samples. Solid analyte was converted into a gaseous form which then reacts with an indicator reagent. Change in absorbance was used to quantitate the analyte. Stirring with a magnetic bar was employed to facilitate the evaporation of the gas. Unlike the pervaporation technique, hydrophobic membrane was not required for this MBL-VP technique. Application of the membraneless technique for direct determination of calcium carbonate in calcium supplements, has shown it to be very precise (RSD = 2.5% for 0.16 mmol CO₃^2-), with detection limit of 0.5 mg CaCO₃. Results by this method agreed well with flame atomic absorption spectrometric method. Sample throughput was 20 samples h^-1.

Sinigalliano, C.D., M.B. Gidley, T. Shibata, D. Whitman, T.H. Dixon, E. Laws, A. Hou, D. Bachoon, L. Brand, L. Amaral-Zettler, R.J. Gast, G.F. Steward, O.D. Nigro, R. Fujioka, W.Q. Betancourt, G. Vithanage, J. Mathews, L.E. Fleming, and H.M. Solo-Gabriele. Impacts of Hurricanes Katrina and Rita on the microbial landscape of the New Orleans area. Proceedings of the National Academy of Sciences, 104(21):9029-9034 (2007).

Floodwaters in New Orleans from Hurricanes Katrina and Rita were observed to contain high levels of fecal indicator bacteria and microbial pathogens, generating concern about long-term impacts of these floodwaters on the sediment and water quality of the New Orleans area and Lake Pontchartrain. We show here that fecal indicator microbe concentrations in offshore waters from Lake Pontchartrain returned to prehurricane concentrations within two months of the flooding induced by these hurricanes. Vibrio and Legionella species within the lake were more abundant in samples collected shortly after the floodwaters had receded compared with samples taken within the subsequent three months; no evidence of a long-term hurricane-induced algal bloom was observed. Giardia and Cryptosporidium were detected in canal waters. Elevated levels of fecal indicator bacteria observed in sediment could not be solely attributed to impacts from floodwaters, as both flooded and nonflooded areas exhibited elevated levels of fecal indicator bacteria. Evidence from measurements of Bifidobacterium and bacterial diversity analysis suggest that the fecal indicator bacteria observed in the sediment were from human fecal sources. Epidemiologic studies are highly recommended to evaluate the human health effects of the sediments deposited by the floodwaters.

Sweeney, C., E. Gloor, A.R. Jacobson, R.M. Key, G. McKinley, J.L. Sarmiento, and R. Wanninkhof. Constraining global air-sea gas exchange for CO₂ with recent bomb 14C measurements. Global Biogeochemical Cycles, 21(2):GB2015, doi:10.1029/2006GB002784 (2007).

The ¹⁴CO₂ released into the stratosphere during bomb testing in the early 1960s provides a global constraint on air-sea gas exchange of soluble atmospheric gases like CO₂. Using the most complete database of dissolved inorganic radiocarbon, DI¹⁴C, available to date and a suite of ocean general circulation models in an inverse mode we recalculate the ocean inventory of bomb-produced DI¹⁴C in the global ocean and confirm that there is a 25% decrease from previous estimates using older DI¹⁴C data sets. Additionally, we find a 33% lower globally averaged gas transfer velocity for CO₂ compared to previous estimates (Wanninkhof, 1992) using the NCEP/NCAR Reanalysis 1 1954-2000 where the global mean winds are 6.9 m s^-1. Unlike some earlier ocean radiocarbon studies, the implied gas transfer velocity finally closes the gap between small-scale deliberate tracer studies and global-scale estimates. Additionally, the total inventory of bomb-produced radiocarbon in the ocean is now in agreement with global budgets based on radiocarbon measurements made in the stratosphere and troposphere. Using the implied relationship between wind speed and gas transfer velocity k_s = 0.27 u₁₀² (Sc/660)^-0.5 and standard partial pressure difference climatology of CO₂ we obtain an net air-sea flux estimate of 1.3 � 0.5 PgCyr^-1 for 1995. After accounting for the carbon transferred from rivers to the deep ocean, our estimate of oceanic uptake (1.8 � 0.5 PgCyr^-1) compares well with estimates based on ocean inventories, ocean transport inversions using ocean concentration data, and model simulations.

Thacker, W.C. Data assimilation with inequality constraints. Ocean Modelling, 16(3-4):264-276 (2007).

If values of variables in a numerical model are limited to specified ranges, these restrictions should be enforced when data are assimilated. The simplest option is to assimilate without regard for constraints and then to correct any violations without worrying about additional corrections implied by correlated errors. This paper addresses the incorporation of inequality constraints into the standard variational framework of optimal interpolation with emphasis on our limited knowledge of the underlying probability distributions. Simple examples involving only two or three variables are used to illustrate graphically how active constraints can be treated as error-free data when background errors obey a truncated multi-normal distribution. Using Lagrange multipliers, the formalism is expanded to encompass the active constraints. Two algorithms are presented, both relying on a solution ignoring the inequality constraints to discover violations to be enforced. While explicitly enforcing a subset can, via correlations, correct the others, pragmatism based on our poor knowledge of the underlying probability distributions suggests the expedient of enforcing them all explicitly to avoid the computationally expensive task of determining the minimum active set. If additional violations are encountered with these solutions, the process can be repeated. Simple examples are used to illustrate the algorithms and to examine the nature of the corrections implied by correlated errors.

Thacker, W.C. Estimating salinity to complement observed temperature, Part 1: Gulf of Mexico. Journal of Marine Systems, 65(1-4):224-248 (2007).

This paper and its companion [Thacker, W.C., Sindlinger, L., 2006-this issue. Estimating salinity to complement observed temperature: 2. Northwestern Atlantic. Journal of Marine Systems, doi:10.1016/j.jmarsys.2005.06.007.] document initial efforts in a project with the goal of developing capability for estimating salinity on a region-by-region basis for the world oceans. The primary motivation for this project is to provide information for correcting salinity, and thus density, when assimilating expendable-bathythermograph (XBT) data into numerical simulations of oceanic circulation, while a secondary motivation is to provide information for calibrating salinity from autonomous profiling floats. Empirical relationships between salinity and temperature, which can be identified from archived conductivity-temperature-depth (CTD) data, provide the basis for the salinity estimates. The Gulf of Mexico was chosen as the first region to explore for several reasons: (1) It's geographical separation from the Caribbean Sea and the North Atlantic Ocean makes it a "small ocean" characterized by a deep central basin surrounded by a substantial continental shelf. (2) The archives contain a relatively large number of CTD data that can be used to establish empirical relationships. (3) The sharp fronts associated with the Loop Current and its rings, which separate water with different thermal and haline characteristics, pose a challenge for estimating salinity. In spite of the shelf and the fronts, the relationship between salinity and temperature was found to be sufficiently regular that a single empirical model could be used to estimate salinity on each pressure surface for the entire Gulf for all seasons. In and below the thermocline, root-mean-square estimation errors are small, less than 0.02 psu for pressures greater than 400 dbar, corresponding to potential density errors of less than 0.015 kg/m³. Errors for estimates nearer to the surface can be an order of magnitude larger.

Thacker, W.C., and L.R. Sindlinger. Estimating salinity to complement observed temperature, Part 2: Northwestern Atlantic. Journal of Marine Systems, 65(1-4):249-267 (2007).

This paper addresses the problem of estimating salinity for a large region in the Atlantic Ocean containing the Gulf Stream and its recirculation. Together with Part 1 [Thacker, W.C., 2006-this issue. Estimating salinity to complement observed temperature: 1. Gulf of Mexico. Journal of Marine Systems, doi:10.1016/j.jmarsys.2005.06.008.] dealing with the Gulf of Mexico, this reports on the first efforts of a project for developing world-wide capability for estimating salinity to complement expendable-bathythermograph (XBT) data. Such estimates are particularly important for this region, where the strong frontal contrasts render the task of assimilating XBT data into numerical models more sensitive to the treatment of salinity. Differences in salinity's co-variability with temperature and with longitude, latitude, and day-of-year from the northwestern part of the region with the Gulf Stream to the southeastern part more characteristic of the Sargasso Sea suggested that the region be partitioned to achieve more accurate salinity estimates. In general, accuracies were better in the southeastern sub-region than in the more highly variable northwestern sub-region with root-mean-square estimation errors of 0.15 psu at 25 dbar and 0.02 psu at 300 dbar as compared with 0.35 psu and 0.50 psu, respectively, but in the southeast there was an unexpected error maximum around 1000 dbar where estimates were slightly less accurate than in the northwest. For pressures greater than 1400 dbar root-mean-square errors in both sub-regions were less than 0.02 psu.

Tory, K.J., N.E. Davidson, and M.T. Montgomery. Prediction and diagnosis of tropical cyclone formation in an NWP system, Part III: Diagnosis of developing and nondeveloping storms. Journal of the Atmospheric Sciences, 64(9):3195-3213 (2007).

This is the third of a three-part investigation into tropical cyclone (TC) genesis in the Australian Bureau of Meteorology's Tropical Cyclone Limited Area Prediction System (TC-LAPS), an operational numerical weather prediction (NWP) forecast model. In Parts I and II, a primary and two secondary vortex enhancement mechanisms were illustrated, and shown to be responsible for TC genesis in a simulation of TC Chris. In this paper, five more TC-LAPS simulations are investigated: three developing and two nondeveloping. In each developing simulation the pathway to genesis was essentially the same as that reported in Part II. Potential vorticity (PV) cores developed through low- to middle-tropospheric vortex enhancement in model-resolved updraft cores (primary mechanism) and interacted to form larger cores through diabatic upscale vortex cascade (secondary mechanism). On the system scale, vortex intensification resulted from the large-scale mass redistribution forced by the upward mass flux, driven by diabatic heating, in the updraft cores (secondary mechanism). The nondeveloping cases illustrated that genesis can be hampered by (i) vertical wind shear, which may tilt and tear apart the PV cores as they develop, and (ii) an insufficient large-scale cyclonic environment, which may fail to sufficiently confine the warming and enhanced cyclonic winds, associated with the atmospheric adjustment to the convective updrafts. The exact detail of the vortex interactions was found to be unimportant for qualitative genesis forecast success. Instead the critical ingredients were found to be sufficient net deep convection in a sufficiently cyclonic environment in which vertical shear was less than some destructive limit. The often-observed TC genesis pattern of convection convergence, where the active convective regions converge into a 100-km-diameter center, prior to an intense convective burst and development to tropical storm intensity is evident in the developing TC-LAPS simulations. The simulations presented in this study and numerous other simulations not yet reported on have shown good qualitative forecast success. Assuming such success continues in a more rigorous study (currently under way) it could be argued that TC genesis is largely predictable provided the large-scale environment (vorticity, vertical shear, and convective forcing) is sufficiently resolved and initialized.

Uhlhorn, E.W., P.G. Black, J.L. Franklin, M. Goodberlet, J. Carswell, and A.S. Goldstein. Hurricane surface wind mesurements from an operational Stepped Frequency Microwave Radiometer. Monthly Weather Review, 135(9):3070-3085 (2007).

For the first time, the NOAA/Aircraft Operations Center (AOC) flew stepped frequency microwave radiometers (SFMRs) on both WP-3D research aircraft for operational hurricane surface wind speed measurement in 2005. An unprecedented number of major hurricanes provided ample data to evaluate both instrument performance and surface wind speed retrieval quality up to 70 m s^-1 (Saffir-Simpson category 5). To this end, a new microwave emissivity-wind speed model function based on estimates of near-surface winds in hurricanes by global positioning system (GPS) dropwindsondes is proposed. For practical purposes, utilizing this function removes a previously documented high bias in moderate SFMR-measured wind speeds (10-50 m s^-1), and additionally corrects an extreme wind speed (>60 m s^-1) underestimate. The AOC operational SFMRs yield retrievals that are precise to within ~2% at 30 m s^-1, which is a factor of 2 improvement over the NOAA Hurricane Research Division's SFMR, and comparable to the precision found here for GPS dropwindsonde near-surface wind speeds. A small (1.6 m s^-1), but statistically significant, overall high bias was found for independent SFMR measurements utilizing emissivity data not used for model function development. Across the range of measured wind speeds (10-70 m s^-1), SFMR 10-s averaged wind speeds are within 4 m s^-1 (rms) of the dropwindsonde near-surface estimate, or 5%-25% depending on speed. However, an analysis of eyewall peak wind speeds indicates an overall 2.6 m s^-1 GPS low bias relative to the peak SFMR estimate on the same flight leg, suggesting a real increase in the maximum wind speed estimate due to SFMR's high-density sampling. Through a series of statistical tests, the SFMR is shown to reduce the overall bias in the peak surface wind speed estimate by ~50% over the current flight-level wind reduction method and is comparable at extreme wind speeds. The updated model function is demonstrated to behave differently below and above the hurricane wind speed threshold (~32 m s^-1), which may have implications for air-sea momentum and kinetic energy exchange. The change in behavior is at least qualitatively consistent with recent laboratory and field results concerning the drag coefficient in high wind speed conditions, which show a fairly clear "leveling off" of the drag coefficient with increased wind speed above ~30 m s^-1. Finally, a composite analysis of historical data indicates that the earth-relative SFMR peak wind speed is typically located in the hurricane's right-front quadrant, which is consistent with previous observational and theoretical studies of surface wind structure.

Walsh, K.J.E., M. Fiorino, C.W. Landsea, and K. McInnes. Objectively determined resolution-dependent threshold criteria for the detection of tropical cyclones in climate models and reanalyses. Journal of Climate, 20(10):2307-2314 (2007).

Objectively derived resolution-dependent criteria are defined for the detection of tropical cyclones in model simulations and observationally based analyses. These criteria are derived from the wind profiles of observed tropical cyclones, averaged at various resolutions. Both an analytical wind profile model and two-dimensional observed wind analyses are used. The results show that the threshold wind speed of an observed tropical cyclone varies roughly linearly with resolution. The criteria derived here are compared to the numerous different criteria previously employed in climate model simulations. The resulting method provides a simple means of comparing climate model simulations and reanalyses.

Wang, C. Variability of the Caribbean low-level jet and its relations to climate. Climate Dynamics, 29(4):411-422 (2007).

A maximum of easterly zonal wind at 925 hPa in the Caribbean region is called the Caribbean Low-Level Jet (CLLJ). Observations show that the easterly CLLJ varies semi-annually, with two maxima in the summer and winter and two minima in the fall and spring. Associated with the summertime strong CLLJ are a maximum of sea level pressure (SLP), a relative minimum of rainfall (the mid-summer drought), and a minimum of tropical cyclogenesis in July in the Caribbean Sea. It is found that both the meridional gradients of sea surface temperature (SST) and SLP show a semi-annual feature, consistent with the semi-annual variation of the CLLJ. The CLLJ anomalies vary with the Caribbean SLP anomalies that are connected to the variation of the North Atlantic Subtropical High (NASH). In association with the cold (warm) Caribbean SST anomalies, the atmosphere shows the high (low) SLP anomalies near the Caribbean region that are consistent with the anomalously strong (weak) easterly CLLJ. The CLLJ is also remotely related to the SST anomalies in the Pacific and Atlantic, reflecting that these SST variations affect the NASH. During the winter, warm (cold) SST anomalies in the tropical Pacific correspond to a weak (strong) easterly CLLJ. However, this relationship is reversed during the summer. This is because the effects of ENSO on the NASH are opposite during the winter and summer. The CLLJ varies in phase with the North Atlantic Oscillation (NAO) since a strong (weak) NASH is associated with a strengthening (weakening) of both the CLLJ and the NAO. The CLLJ is positively correlated with the 925-hPa meridional wind anomalies from the vocean to the United States via the Gulf of Mexico. Thus, the CLLJ and the meridional wind carry moisture from the ocean to the central United States, usually resulting in an opposite (or dipole) rainfall pattern in the tropical North Atlantic Ocean and Atlantic warm pool versus the central United States.

Wang, C., and S.-K. Lee. Atlantic warm pool, Caribbean low-level jet, and their potential impact on Atlantic hurricanes. Geophysical Research Letters, 34(2):L02703, doi:10.1029/2006GL028579 (2007).

The Atlantic Warm Pool (AWP) is a large body of warm water (warmer than 28.5�C) that appears in the Gulf of Mexico, the Caribbean Sea, and the western tropical North Atlantic during the summer and fall. Located to its northeastern side is the North Atlantic Subtropical High (NASH) that produces the easterly trade winds in the tropics. The trade winds carry moisture from the tropical North Atlantic into the Caribbean Sea where the flow intensifies, forming the Caribbean Low-Level Jet (CLLJ). This paper finds that the easterly CLLJ is maximized in the summer and winter, whereas it is minimized in the fall and spring. The semi-annual feature of the CLLJ results from the semi-annual variation of sea level pressure in the Caribbean region associated with the east-west excursion of the NASH. The AWP's impact is to weaken the summertime NASH, especially at its southwestern edge and thus weaken the easterly CLLJ. The weakening of the easterly CLLJ, in conjunction with the AWP-induced change of upper-level wind, reduces the tropospheric vertical wind shear that favors hurricane formation and intensification during August-October.

Wang, C., S.-K. Lee, and D.B. Enfield. Impact of the Atlantic warm pool on the summer climate of the western hemisphere. Journal of Climate, 20(20):5021-5040 (2007).

The Atlantic warm pool (AWP) is a large body of warm water that comprises the Gulf of Mexico, the Caribbean Sea, and the western tropical North Atlantic. Located to its northeastern side is the North Atlantic subtropical high (NASH), which produces the tropical easterly trade winds. The easterly trade winds carry moisture from the tropical North Atlantic into the Caribbean Sea, where the flow intensifies, forming the Caribbean low-level jet (CLLJ). The CLLJ then splits into two branches: one turning northward and connecting with the Great Plains low-level jet (GPLLJ), and the other continuing westward across Central America into the eastern North Pacific. The easterly CLLJ and its westward moisture transport are maximized in the summer and winter, whereas they are minimized in the fall and spring. This semiannual feature results from the semiannual variation of sea level pressure in the Caribbean region owing to the westward extension and eastward retreat of the NASH. The NCAR Community Atmospheric Model and observational data are used to investigate the impact of the climatological annual mean AWP on the summer climate of the Western Hemisphere. Two groups of the model ensemble runs with and without the AWP are performed and compared. The model results show that the effect of the AWP is to weaken the summertime NASH, especially at its southwestern edge. The AWP also strengthens the summertime continental low over the North American monsoon region. In response to these pressure changes, the CLLJ and its moisture transport are weakened, but its semiannual feature does not disappear. The weakening of the easterly CLLJ increases (decreases) moisture convergence to its upstream (downstream) and thus enhances (suppresses) rainfall in the Caribbean Sea (in the far eastern Pacific west of Central America). Model runs show that the AWP's effect is to always weaken the southerly GPLLJ. However, the AWP strengthens the GPLLJ's northward moisture transport in the summer because the AWP-induced increase of specific humidity overcomes the weakening of southerly wind, and vice versa in the fall. Finally, the AWP reduces the tropospheric vertical wind shear in the main development region that favors hurricane formation and development during August-October.

Wang, Z.A., X. Liu, R.H. Byrne, R. Wanninkhof, R.E. Bernstein, E.A. Kaltenbacher, and J. Patten. Simultaneous spectrophotometric flow-through measurements of pH, carbon dioxide fugacity, and total inorganic carbon in seawater. Analytica Chimica Acta, 596(1):23-36 (2007).

An autonomous multi-parameter flow-through CO₂ system has been developed to simultaneously measure surface seawater pH, carbon dioxide fugacity (fCO₂), and total dissolved inorganic carbon (DIC). All three measurements are based on spectrophotometric determinations of solution pH at multiple wavelengths using sulfonephthalein indicators. The pH optical cell is machined from a PEEK polymer rod bearing a bore-hole with an optical pathlength of ~15 cm. The fCO₂ optical cell consists of Teflon AF 2400 (DuPont) capillary tubing sealed within the bore-hole of a PEEK rod. This Teflon AF tubing is filled with a standard indicator solution with a fixed total alkalinity, and forms a liquid core waveguide (LCW). The LCW functions as both a long pathlength (~15 cm) optical cell and a membrane that equilibrates the internal standard solution with external seawater. fCO₂ is then determined by measuring the pH of the internal solution. DIC is measured by determining the pH of standard internal solutions in equilibrium with seawater that has been acidified to convert all forms of DIC to CO₂. The system runs repetitive measurement cycles with a sampling frequency of ~7 samples (21 measurements) per hour. The system was used for underway measurements of sea surface pH, fCO₂, and DIC during the CLIVAR/CO₂ A16S cruise in the South Atlantic Ocean in 2005. The field precisions were evaluated to be 0.0008 units for pH, 0.9 µatm for fCO₂, and 2.4 µmol kg^-1 for DIC. These field precisions are close to those obtained in the laboratory. Direct comparison of our measurements and measurements obtained using established standard methods revealed that the system achieved field agreements of 0.0012 � 0.0042 units for pH, 1.0 � 2.5 µatm for fCO₂, and 2.2 � 6.0 µmol kg^-1 for DIC. This system integrates spectrophotometric measurements of multiple CO₂ parameters into a single package suitable for observations of both seawater and freshwater.

Wanninkhof, R. The impact of different gas exchange formulations and wind speed products on global air-sea CO₂ fluxes. In Transport at the Air-Sea Interface: Measurements, Models, and Parameterizations, C.S. Garbe, R.A. Handler, and B. Jahne (eds.). Springer-Verlag, 1-23 (2007).

Significant advances have been made over the last decade in estimating air-sea CO₂ fluxes over the ocean by the bulk formulation that expresses the flux as the product of the gas transfer velocity and the concentration difference of aqueous CO₂ over the liquid boundary layer. This has resulted in a believable global monthly climatology of air-sea CO₂ fluxes over the ocean on a 4� by 5� grid. It is shown here that the global air-sea CO₂ fluxes are very sensitive to estimates of gas transfer velocity and the parameterization of gas transfer with wind. Wind speeds can now be resolved at sufficient temporal and spatial resolution that they should not limit the estimates, but the absolute magnitudes of winds for different wind products differ significantly. It is recommended to use satellite-derived wind products that have the appropriate resolution instead of assimilated products that often do not appropriately resolve variability on sub-daily and sub-25-km space scales. Parameterizations of gas exchange with wind differ in functional form and magnitude but the difference between the most-used quadratic relationships is about 15%. Based on current estimates of uncertainty of the air-water CO₂ concentration differences, the winds, and the gas exchange-wind speed parameterization, each parameter contributes similarly to the overall uncertainty in the flux that is estimated at 25%.

Wanninkhof, R., A. Olsen, and J.A. Trinanes. Air-sea CO₂ fluxes in the Caribbean Sea from 2002-2004. Journal of Marine Systems, 66(1-4):272-284 (2007).

Air-sea fluxes in the Caribbean Sea are presented based on measurements of partial pressure of CO₂ in surface seawater, pCO_2sw, from an automated system onboard the cruise ship Explorer of the Seas for 2002 through 2004. The pCO_2sw values are used to develop algorithms of pCO_2sw based on sea surface temperature (SST) and position. The algorithms are applied to assimilated SST data and remotely sensed winds on a 1� by 1� grid to estimate the fluxes on weekly timescales in the region. The positive relationship between pCO_2sw and SST is lower than the isochemical trend, suggesting counteracting effects from biological processes. The relationship varies systematically with location with a stronger dependence further south. Furthermore, the southern area shows significantly lower pCO_2sw in the fall compared to the spring at the same SST, which is attributed to differences in salinity. The annual algorithms for the entire region show a slight trend between 2002 and 2004, suggesting an increase of pCO_2sw over time. This is in accord with the increasing pCO_2sw due to the invasion of anthropogenic CO₂. The annual fluxes of CO₂ yield a net invasion of CO₂ to the ocean that ranges from -0.04 to -1.2 mol m^-2 year^-1 over the three years. There is a seasonal reversal in the direction of the flux with CO₂ entering into the ocean during the winter and an evasion during the summer. Year-to-year differences in flux are primarily caused by temperature anomalies in the late winter and spring period resulting in changes in invasion during these seasons. An analysis of pCO_2sw before and after Hurricane Frances (September 4-6, 2004), and wind records during the storm suggest a large local enhancement of the flux but minimal influence on annual fluxes in the region.

Willoughby, H.E., E.N. Rappaport, and F.D. Marks. Hurricane forecasting: The state of the art. Natural Hazards Review, 8(3):45-49 (2007).

In this article, we summarize current forecasting practice, the performance of the forecasting enterprise, and the impacts of tropical cyclones from a meteorological perspective. In the past, a forecast was considered successful if it predicted the hurricane's position and intensity 12-72 h into the future. By the 1990s, forecast users came to expect more specific details such as spatial distributions of rainfall, winds, flooding, and high seas. In the early 21st century, forecasters extended their time horizons to 120 h. Meteorologists have maintained homogeneous statistics on forecast accuracy for more than 50 years. These verification statistics are reliable metrics of meteorological performance. In terms of outcomes, forecasting in the late 20th century prevented 66-90% of the hurricane-related deaths in the United States that would have resulted from techniques used in the 1950s, but it is difficult to demonstrate an effect on property damage. The economic and human consequences of the response to forecasts and warnings are also poorly known. A final key concern is how to frame forecasts to address users' needs and to elicit optimum responses.

Wu, C.-C., K.-H. Chou, P.-H. Lin, S.D. Aberson, M.S. Peng, and T. Nakazawa. The impact of dropsonde data on typhoon track forecasting in DOTSTAR. Weather and Forecasting, 22(6):1157-1176 (2007).

Starting from 2003, a new typhoon surveillance program, Dropwindsonde Observations for Typhoon Surveillance near the Taiwan Region (DOTSTAR), was launched. During 2004, 10 missions for eight typhoons were conducted successfully with 155 dropwindsondes deployed. In this study, the impact of these dropwindsonde data on tropical cyclone track forecasts has been evaluated with five models (four operational and one research models). All models, except the Geophysical Fluid Dynamics Laboratory (GFDL) hurricane model, show the positive impact that the dropwindsonde data have on tropical cyclone track forecasts. During the first 72 h, the mean track error reductions in the National Centers for Environmental Predictions (NCEP) Global Forecast System (GFS), the Navy Operational Global Atmospheric Prediction System (NOGAPS) of the Fleet Numerical Meteorology and Oceanography Center (FNMOC), and the Japanese Meteorological Agency (JMA) Global Spectral Model (GSM) are 14%, 14%, and 19%, respectively. The track error reduction in the Weather Research and Forecasting (WRF) model, in which the initial conditions are directly interpolated from the operational GFS forecast, is 16%. However, the mean track improvement in the GFDL model is a statistically insignificant 3%. The 72-h-average track error reduction from the ensemble mean of the above three global models is 22%, which is consistent with the track forecast improvement in Atlantic tropical cyclones from surveillance missions. In all, despite the fact that the impact of the dropwindsonde data is not statistically significant due to the limited number of DOTSTAR cases in 2004, the overall added value of the dropwindsonde data in improving typhoon track forecasts over the western North Pacific is encouraging. Further progress in the targeted observations of the dropwindsonde surveillances and satellite data, and in the modeling and data assimilation system, is expected to lead to even greater improvement in tropical cyclone track forecasts.

Zhang, J.-Z., and X.-L. Huang. Relative importance of solid-phase phosphorus and iron on the sorption behavior of sediments. Environmental Science and Technology, 41(8):2789-2795 (2007).

Of all the metal oxide particles, amorphous iron oxides have the greatest adsorption capacity for phosphate. Coastal sediments are often coated with terrigenous amorphous iron oxides, and those containing high iron are thought to have a high adsorption capacity. However, this conventional wisdom is based largely upon studies of phosphate adsorption on laboratory-synthesized minerals themselves containing no phosphorus. Using natural sediments that contain variable phosphorus and iron, our results demonstrate that the exchangeable phosphate rather than the iron oxides of sediments governs the overall sorption behavior. The iron oxide content becomes important only in sediments that are poor in phosphorus. A total of 40 sampling sites across the Florida Bay provide detailed spatial distributions both of the sediment's zero equilibrium phosphate concentration (EPC₀) and of the distribution coefficient (K_d) that are consistent with the distribution of the exchangeable phosphate content of the sediment. This study provides the first quantitative relationships between sorption characteristics (EPC₀ and K_d) and the exchangeable phosphate content of natural sediments. **2006**

Aberson, S.D., and B.J. Etherton. Targeting and data assimilation studies during Hurricane Humberto (2001). Journal of the Atmospheric Sciences, 63(1):175-186 (2006).

Two operational synoptic surveillance missions were conducted by the National Oceanic and Atmospheric Administration into Hurricane Humberto (2001). Forecasts from two leading dynamical hurricane track forecast models were improved substantially during the watch and warning period before a projected landfall by the assimilation of the additional dropwindsonde data. Feasibility tests with a barotropic model suggest that further improvements may be obtained by the use of the ensemble transform Kalman filter for assimilating these additional data into the model. This is the first effort to assimilate data into a hurricane model using the ensemble transform Kalman filter.

Aberson, S.D., and J.B. Halverson. Kelvin-Helmholtz billows in the eyewall of Hurricane Erin. Monthly Weather Review, 134(3):1036-1038 (2006).

A photograph of vertically aligned KelvinHelmholtz billows in the eastern eyewall of Hurricane Erin on 10 September 2001 is presented. The vertical shear instability in the horizontal winds necessary to produce the billows is confirmed with a high-altitude dropwindsonde observation. This shear instability is not known to be common in tropical cyclone eyewalls and is likely only in cases with a very large eyewall tilt. However, research and reconnaissance aircraft pilots need to be aware of the possibility of their existence, along with other types of hazardous conditions, in such rare circumstances.

Aberson, S.D., and D.P. Stern. Extreme horizontal winds measured by dropwindsondes in hurricanes. Preprints, 27th Conference on Hurricanes and Tropical Meteorology, Monterey, CA, April 24-28, 2006. American Meteorological Society, Boston, 4 pp. (CD-ROM) (2006).

No abstract.

Aberson, S.D., J.P. Dunion, and F.D. Marks. A photograph of a wavenumber-2 asymmetry in the eye of Hurricane Erin. Journal of the Atmospheric Sciences, 63(1):387-391 (2006).

A photograph of a wavenumber-2 asymmetry in the eye of Hurricane Erin taken during a NOAA WP-3D research flight during the Fourth Convection and Moisture Experiment (CAMEX-4) field program on 10 September 2001 is described. The photograph of the cloud structure within the eye is evaluated using airborne and satellite remote sensing observations, and a possible explanation for the asymmetry is presented.

Aberson, S.D., M.T. Montgomery, M.M. Bell, and M.L. Black. Hurricane Isabel (2003): New insights into the physics of intense storms, Part II: Extreme localized wind. Bulletin of the American Meteorological Society, 87(10):1349-1354 (2006).

An unprecedented dataset of category-5 Hurricane Isabel was collected on 12-14 September 2003. This two-part series focuses on novel dynamical and thermodynamical aspects of Isabel's inner-core structure on 13 September. In Part I, using a composite of dropwindsonde and in situ aircraft data, the authors suggested that the axisymmetric structure of Isabel showed that the storm was superintense. Mesocyclones seen clearly in satellite imagery within the eye of Hurricane Isabel are hypothesized to mix high-entropy air at low levels in the eye into the eyewall, stimulating explosive convective development and a concomitant local horizontal wind acceleration. Part II focuses on a unique set of observations into an extraordinary small- (miso) scale cyclonic feature inside of the inner edge of the eyewall of Hurricane Isabel. A dropwindsonde released into this feature measured the strongest known horizontal wind in a tropical cyclone. This particular observation is discussed in the context of concurrent observations from airborne Doppler radar and other airborne instruments. These observations show wind even stronger than the system-scale superintense wind suggested in Part I. Speculation on the frequency of occurrence of these "little whirls" and their potentially catastrophic impacts are presented.

Aberson, S.D., M.L. Black, R.A. Black, R.W. Burpee, J.J. Cione, C.W. Landsea, and F.D. Marks. Thirty years of tropical cyclone research with the NOAA P-3 aircraft. Bulletin of the American Meteorological Society, 87(8):1039-1055 (2006).

In 1976 and 1977, the National Oceanic and Atmospheric Administration purchased two customized WP-3D (P-3) aircraft to conduct tropical cyclone (TC) research. During their first 30 years, the P-3s have proved to be invaluable research platforms, obtaining data at the micro- to synoptic scale, with missions conducted in 134 TCs in the Atlantic and eastern Pacific Oceans and near Australia. Analyses of the observations led to many new insights about TC structure, dynamics, thermodynamics, and environmental interactions. The real-time use of the information by the National Hurricane and Environmental Modeling Centers of the National Centers for Environmental Prediction (NCEP), as well as later research, has helped to increase the accuracy of wind, flood, and storm surge forecasts and severe weather warnings and has resulted in significant improvements to operational numerical model guidance for TC-track forecasts. In commemoration of the first 30 years of research with these aircraft, this manuscript presents a brief overview of the instrumentation aboard the aircraft and the major research findings during this period.

Atlas, R., O. Reale, B.-W. Shen, and S.-J. Lin. The use of remotely sensed data and innovative modeling to improve hurricane prediction. In Algorithms and Technologies for Multispectral, Hyperspectral, and Ultraspectral Imagery XII, S.S. Shen and P.E. Lewis (eds.). Proceedings, SPIE, 6233:62330U, doi:10.1117/12.673221, 8 pp. (2006).

The assimilation of remotely sensed data from aircraft and satellites has contributed substantially to the current accuracy of operational hurricane forecasting. In the 1960s, satellite imagery revolutionized hurricane detection and forecasting. Since that time, quantitative remotely sensed data (e.g., atmospheric motion winds, passive infrared and microwave radiances or retrievals of temperature, moisture, surface wind and rain rate, active microwave measurements of surface wind and rain rate) and significant advances in modeling and data assimilation have increased the accuracy of hurricane track forecasts very significantly. The development of advanced next-generation models in combination with new types of remotely sensed observation (e.g., space-based lidar winds) should yield significant further improvements in the timing and location of landfall and in the predicted intensification of hurricanes.

Atlas, R., O. Reale, J. Ardizzone, J. Terry, J.-C. Jusem, E. Brin, D. Bungato, and P. Woiceshyn. Geophysical validation of WINDSAT surface wind data and its impact on numerical weather prediction. In Atmospheric and Environmental Remote Sensing Data Processing and Utilization II: Perspective on Calibration/Validation Initiatives and Strategies, A.H. Huang and H.J. Bloom (eds.). Proceedings, SPIE, 6301:63010C, doi:10.1117/12.680923, 7 pp. (2006).

Ayina, L.-H., A. Bentamy, A.M. Mestas-Nunez, and G. Madec. The impact of satellite winds and latent heat fluxes in a numerical simulation of the tropical Pacific Ocean. Journal of Climate, 19(22):5889-5902 (2006).

Several oceanic operational programs use remotely sensed fluxes to complement atmospheric operational analyses from major national weather prediction centers. The main goal of this study is to evaluate the ability of the ocean model (ORCA) to correctly simulate the dynamic of the tropical Pacific Ocean in 1996-98 when forced by the satellite turbulent fluxes (wind stress and latent heat fluxes). The results are compared with the oceanic response resulting from forcing the model with the European Centre for Medium-Range Weather Forecasts (ECMWF) operational analysis. Three sensitivity simulations forced with satellite and atmospheric analysis fields are performed. The control experiment is forced with the ECMWF fluxes. The solutions of these simulations are compared with data from the Tropical Atmosphere-Ocean (TAO) buoys and from sea surface temperatures analysis by Reynolds and Smith in the equatorial Pacific Ocean. The analysis results indicate that the model reproduces well the major spatial and temporal oceanic structures including the main characteristics of the 1997-98 El Ni�o. More specifically, the comparisons with buoys indicate that the experiment forced by the winds and the satellite latent heat fluxes is closer to the observations. They provide weak rms difference and strong correlations along the whole 500-m depth column. Furthermore, the correlations with the SST analysis vary between 75% and 95% compared to 65% and 77% for the experiment forced by ECMWF fluxes. The currents in the first 350 m also show a strong sensitivity to satellite turbulent fluxes.

Baringer, M.O., and C.S. Meinen. Global oceans: Thermohaline circulation. In State of the Climate in 2005, K.A. Shein, A.M. Waple, H.J. Diamond, and J.M. Levy (eds.). Bulletin of the American Meteorological Society, 87(6):S27-S28 (2006).

No abstract.

Baringer, M.O., G.J. Goni, and S.L. Garzoli. Atlantic high density XBT lines, pp. 181-182. In Annual Report on the State of the Ocean and the Ocean Observing System for Climate (FY-2005), J.M. Levy, D.M. Stanitski, and P. Arkin (eds.). NOAA Office of Climate Observation, Silver Spring, MD, 337 pp. (2006).

No abstract.

Baringer, M.O., C.S. Meinen, and S.L. Garzoli. The meridional overturning circulation and oceanic heat transport, pp. 68-73. In Annual Report on the State of the Ocean and the Ocean Observing System for Climate (FY-2005), J.M. Levy, D.M. Stanitski, and P. Arkin (eds.). NOAA Office of Climate Observation, Silver Spring, MD, 337 pp. (2006).

Coupled ocean-atmosphere models have demonstrated a strong correlation between the meridional overturning circulation (MOC) and climate variability. NOAA has a 20+ year history of making observations of some of the North Atlantic MOC components, however the first basin-wide time-series observations are now being made and a long-term monitoring system is being designed. Results from 2005 indicate little change in the Florida Current compared to the long-term mean of the transport obtained from cable data, and in the ocean interior there is little evidence of meaningful differences from the long-term averages of the limited historical data that exists for comparison.

Baringer, M.O., C.S. Meinen, and S.L. Garzoli. Western boundary time series in the Atlantic Ocean, pp. 150-158. In Annual Report on the State of the Ocean and the Ocean Observing System for Climate (FY-2005), J.M. Levy, D.M. Stanitski, and P. Arkin (eds.). NOAA Office of Climate Observation, Silver Spring, MD, 337 pp.(2006).

No abstract.

Baringer, M.O., S.L. Garzoli, G.J. Goni, W.C. Thacker, and R. Lumpkin. Quarterly reports on the state of the ocean: Meridional heat transport variability in the Atlantic Ocean, pp. 265-267. In Annual Report on the State of the Ocean and the Ocean Observing System for Climate (FY-2005), J.M. Levy, D.M. Stanitski, and P. Arkin (eds.). NOAA Office of Climate Observation, Silver Spring, MD, 337 pp. (2006).

No abstract.

Bell, G.D., E. Blake, K.C. Mo, C.W. Landsea, R. Pasch, M. Chelliah, and S.B. Goldenberg. Tropical cyclones: Atlantic basin. In State of the Climate in 2005, K.A. Shein, A.M. Waple, H.J. Diamond, and J.M. Levy (eds.). Bulletin of the American Meteorological Society, 87(6):S33-S37 (2006).

No abstract.

Bell, G.D., E. Blake, K.C. Mo, C.W. Landsea, R. Pasch, M. Chelliah, S.B. Goldenberg, and H.J. Diamond. The record breaking 2005 Atlantic hurricane season. In State of the Climate in 2005, K.A. Shein, A.M. Waple, H.J. Diamond, and J.M. Levy (eds.). Bulletin of the American Meteorological Society, 87(6):S44-S45 (2006).

No abstract.

Black, P.G., E.A. D'Asaro, J.R. French, and W.M. Drennan. Synthesis of major results from the Coupled Boundary Layer Air-Sea Transfer Experiment (CBLAST) in hurricanes (2003-2004). Preprints, 27th Conference on Hurricanes and Tropical Meteorology, Monterey, CA, April 24-28, 2006. American Meteorological Society, Boston, 8 pp. (CD-ROM) (2006).

No abstract.

Brandt, S., J.C. Hendee, P. Levin, J. Phinney, D. Scheurer, and F. Schwing. White Paper #5: Ecological forecasting, pp. 52-63. In Ecosystem Science Capabilities Required to Support NOAA's Mission in the Year 2020, S.A. Murawski and G.C. Matlock (eds.). NOAA Technical Memorandum, NMFS-F/SPO-74, 97 pp. (2006).

No abstract.

Carter, G., P. Restrepo, J. Hameedi, P.B. Ortner, C. Sellinger, J. Stein, and T. Beechie. White Paper #3: Freshwater issues, pp. 29-39. In Ecosystem Science Capabilities Required to Support NOAA's Mission in the Year 2020, S.A. Murawski and G.C. Matlock (eds). NOAA Technical Memorandum, NMFS-F/SPO-74, 97 pp. (2006).

No abstract.

Casal, T.G.D., L.M. Beal, and R. Lumpkin. A North Atlantic deep-water eddy in the Agulhas Current system. Deep-Sea Research, Part I, 53(10):1718-1728 (2006).

One hundred and twelve stations of CTDO2 and LADCP were collected in the Agulhas Current system as part of the Agulhas Undercurrent experiment (AUCE) in March 2003. Along an offshore section, at approximately 35.6°S and 27.3°E to the northwest of the tip of the Agulhas Plateau, an unusual feature was revealed between 2200 and 3500 m depth, imbedded in the northward moving NADW layer. An anomalously high salinity of 34.83, 0.03 saltier than the surrounding water, was observed. Maximums in the potential temperature and oxygen were also found, with isotherms dropping by about 250 m over 50 km and a doming of the oxygen layers. From the convex lens structure of the neutral surfaces, we conclude that we sampled an anticyclonic eddy of NADW. Since the LADCP data reveal deep velocities up to 20 cm s^-1, yet no anticyclonic circulation, whereas the geostrophic velocity referenced to the bottom shows a weak anticyclonic circulation, we inferred that we sampled the outer edge of the eddy and not its core. From an analysis of the water properties within the eddy and a comparison with known properties in the SE Atlantic Ocean and SW Indian Ocean, we conclude that the eddy was formed in the Agulhas Retroflection region. We speculate that the eddy was the result of an instability in the NADW slope current, which flows from the SE Atlantic around the Agulhas Bank. A deeply penetrating Agulhas Ring spun up the deep waters, pinching off an eddy, which later detached from the slope current and was carried southward. Once offshore, it coupled with the surface Agulhas Return Current, whose meandering path advected the eddy northeastward and ejected it over the Agulhas Plateau.

Chahine, M.T., T.S. Pagano, H.H. Aumann, R. Atlas, C. Barnet, J. Blaisdell, L. Chen, M. Divakarla, E.J. Fetzer, M. Goldberg, C. Gautier, S. Granger, S. Hannon, F.W. Irion, R. Kakar, E. Kalnay, B.H. Lambrigtsen, S.-Y. Lee, J. LeMarshall, W.W. McMillan, L. McMillin, E.T. Olsen, H. Revercomb, P. Rosenkranz,W.L. Smith, D. Staelin, L.L. Strow, J. Susskind, D. Tobin, W. Wolf, and L. Zhou. AIRS: Improving weather forecasting and providing new data on greenhouse gases. Bulletin of the American Meteorological Society, 87(7):911-926 (2006).

The Atmospheric Infrared Sounder (AIRS) and its two companion microwave sounders, AMSU and HSB, were launched into polar orbit onboard the NASA Aqua Satellite in May 2002. NASA required the sounding system to provide high-quality research data for climate studies and to meet NOAA's requirements for improving operational weather forecasting. The NOAA requirement translated into global retrieval of temperature and humidity profiles with accuracies approaching those of radiosondes. AIRS also provides new measurements of several greenhouse gases, such as CO₂, CO, CH₄, O₃, SO₂, and aerosols. The assimilation of AIRS data into operational weather forecasting has already demonstrated significant improvements in global forecast skill. At NOAA/NCEP, the improvement in the forecast skill achieved at 6 days is equivalent to gaining an extension of forecast capability of six hours. This improvement is quite significant when compared to other forecast improvements over the last decade. In addition to NCEP, ECMWF and the Met Office have also reported positive forecast impacts due AIRS. AIRS is a hyperspectral sounder with 2,378 infrared channels between 3.7 and 15.4 µm. NOAA/NESDIS routinely distributes AIRS data within 3 hours to NWP centers around the world. The AIRS design represents a breakthrough in infrared space instrumentation with measurement stability and accuracies far surpassing any current research or operational sounder. The results we describe in this paper are "work in progress," and although significant accomplishments have already been made much more work remains in order to realize the full potential of this suite of instruments.

Chen, S.S., J.A. Knaff, and F.D. Marks. Effects of vertical wind shear and storm motion on tropical cyclone rainfall asymmetries deduced from TRMM. Monthly Weather Review, 134(11):3190-3208 (2006).

Vertical wind shear and storm motion are two of the most important factors contributing to rainfall asymmetries in tropical cyclones (TCs). Global TC rainfall structure, in terms of azimuthal distribution and asymmetries relative to storm motion, has been previously described using the Tropical Rainfall Measuring Mission Microwave Imager rainfall estimates. The mean TC rainfall distribution and the wavenumber-1 asymmetry vary with storm intensity and geographical location among the six oceanic basins. This study uses a similar approach to investigate the relationship between the structure of TC rainfall and the environmental flow by computing the rainfall asymmetry relative to the vertical wind shear. The environmental vertical wind shear is defined as the difference between the mean wind vectors of the 200- and 850-hPa levels over an outer region extending from the radius of 200-800 km around the storm center. The wavenumber-1 maximum rainfall asymmetry is downshear left (right) in the Northern (Southern) Hemisphere. The rainfall asymmetry decreases (increases) with storm intensity (shear strength). The rainfall asymmetry maximum is predominantly downshear left for shear values > 7.5 m s^-1. Large asymmetries are usually observed away from the TC centers. As TC intensity increases, the asymmetry maximum shifts upwind to the left. The analysis is further extended to examine the storm motion and the vertical wind shear and their collective effects on TC rainfall asymmetries. It is found that the vertical wind shear is a dominant factor for the rainfall asymmetry when shear is >5 m s^-1. The storm motion-relative rainfall asymmetry in the outer rainband region is comparable to that of shear relative when the shear is <5 m s^-1, suggesting that TC translation speed becomes an important factor in the low shear environment. The overall TC rainfall asymmetry depends on the juxtaposition and relative magnitude of the storm motion and environmental shear vectors in all oceanic basins.

Chou, K.-H., C.-C. Wu, P.-H. Lin, S.D. Aberson, M. Peng, and T. Nakazawa. The impact of dropsonde data from DOTSTAR on tropical cyclone track forecasting. Preprints, 27th Conference on Hurricanes and Tropical Meteorology, Monterey, CA, April 24-28, 2006. American Meteorological Society, Boston, 12 pp. (CD-ROM) (2006).

No abstract.

Contreras, R.F., D. Esteban Fernandez, P.S. Chang, and P.G. Black. High resolution airborne radar measurements of Hurricane Isabel. Preprints, 27th Conference on Hurricanes and Tropical Meteorology, Monterey, CA, April 24-28, 2006. American Meteorological Society, Boston, 4 pp. (CD-ROM) (2006).

The Imaging Wind and Rain Airborne Profiler (IWRAP) is a dual-frequency, conically-scanning Doppler radar that measures high resolution profiles of rain's effective reflectivity Ze and Doppler velocity, as well as surface wind vectors via scatterometry. IWRAP was flown aboard a NOAA WP-3D aircraft during the 2002, 2003, 2004, and 2005 hurricane seasons as part of the ONR's Coupled Boundary Layers Air-Sea Transfer (CBLAST) experiment, NASA's Ocean Vector Winds research, and the NOAA/NESDIS Ocean Winds and Rain experiments. We will start with a description of IWRAP and its capabilities. Following this we will introduce a new dataset available to the CBLAST community. We will finish with high resolution radar observations of Hurricane Isabel with an emphasis on the 3-D structure of the storm, especially in the atmospheric boundary layer (ABL).

Corbosiero, K.L., J. Molinari, A.R. Aiyyer, and M.L. Black. The structure and evolution of Hurricane Elena (1985), Part II: Convective asymmetries and evidence for vortex Rossby waves. Monthly Weather Review, 134(11):3073-3091 (2006).

A portable data recorder attached to the Weather Surveillance Radar-1957 (WSR-57) in Apalachicola, Florida, collected 313 radar scans of the reflectivity structure within 150 km of the center of Hurricane Elena (in 1985) between 1310 and 2130 UTC 1 September. This high temporal and spatial (750 m) resolution dataset was used to examine the evolution of the symmetric and asymmetric precipitation structure in Elena as the storm rapidly strengthened and attained maximum intensity. Fourier decomposition of the reflectivity data into azimuthal wavenumbers revealed that the power in the symmetric (wavenumber 0) component dominated the reflectivity pattern at all times and all radii by at least a factor of 2. The wavenumber 1 asymmetry accounted for less than 20% of the power in the reflectivity field on average and was found to be forced by the environmental vertical wind shear. The small-amplitude wavenumber 2 asymmetry in the core was associated with the appearance and rotation of an elliptical eyewall. This structure was visible for nearly 2 h and was noted to rotate cyclonically at a speed equal to half of the local tangential wind. Outside of the eyewall, individual peaks in the power in wavenumber 2 were associated with repeated instances of cyclonically rotating, outward-propagating inner spiral rainbands. Four separate convective bands were identified with an average azimuthal velocity of 25 m s^-1, or ~68% of the local tangential wind speed, and an outward radial velocity of 5.2 m s^-1. The azimuthal propagation speeds of the elliptical eyewall and inner spiral rainbands were consistent with vortex Rossby wave theory. The elliptical eyewall and inner spiral rainbands were seen only in the 6-h period prior to peak intensity, when rapid spinup of the vortex had produced an annular vorticity profile, similar to those that have been shown to support barotropic instability. The appearance of an elliptical eyewall was consistent with the breakdown of eyewall vorticity into mesovortices, asymmetric mixing between the eye and eyewall, and a slowing of the intensification rate. The inner spiral rainbands might have arisen from high eyewall vorticity ejected from the core during the mixing process. Alternatively, because the bands were noted to emanate from the vertical shear-forced deep convection in the northern eyewall, they could have formed through the axisymmetrization of the asymmetric diabatically generated eyewall vorticity.

DeMaria, M., J.A. Knaff, and J. Kaplan. On the decay of tropical cyclone winds crossing narrow landmasses. Journal of Applied Meteorology and Climatology, 45(3):491-499 (2006).

A method is developed to adjust the Kaplan and DeMaria tropical cyclone inland wind decay model for storms that move over narrow landmasses. The basic assumption that the wind speed decay rate after landfall is proportional to the wind speed is modified to include a factor equal to the fraction of the storm circulation that is over land. The storm circulation is defined as a circular area with a fixed radius. Application of the modified model to Atlantic Ocean cases from 1967 to 2003 showed that a circulation radius of 110 km minimizes the bias in the total sample of landfalling cases and reduces the mean absolute error of the predicted maximum winds by about 12%. This radius is about 2 times the radius of maximum wind of a typical Atlantic tropical cyclone. The modified decay model was applied to the Statistical Hurricane Intensity Prediction Scheme (SHIPS), which uses the Kaplan and DeMaria decay model to adjust the intensity for the portion of the predicted track that is over land. The modified decay model reduced the intensity forecast errors by up to 8% relative to the original decay model for cases from 2001 to 2004 in which the storm was within 500 km from land.

DeMaster, D., M. Fogarty, D.M. Mason, G. Matlock, and A. Hollowed. White Paper #2: Management of living marine resources in an ecosystem context, pp. 15-28. In Ecosystem Science Capabilities Required to Support NOAA's Mission in the Year 2020, S.A. Murawski and G.C. Matlock (eds). NOAA Technical Memorandum, NMFS-F/SPO-74, 97 pp. (2006).

No abstract.

Dunion, J.P., J.D. Hawkins, and C.S. Velden. Hunting for Saharan air with the NOAA G-IV jet. Preprints, 27th Conference on Hurricanes and Tropical Meteorology, Monterey, CA, April 24-28, 2006. American Meteorological Society, Boston, 4 pp. (CD-ROM) (2006).

No abstract.

Eastin, M.D., P.D. Reasor, D.S. Nolan, F.D. Marks, and J.F. Gamache. Evolution of low-wavenumber vorticity during rapid intensification: A dual-Doppler analysis. Preprints, 27th Conference on Hurricanes and Tropical Meteorology, Monterey, CA, April 24-28, 2006. American Meteorological Society, Boston, 6 pp. (CD-ROM) (2006).

No abstract.

Enfield, D.B., and L. Cid-Serrano. Projecting the risk of future climate shifts. International Journal of Climatology, 27(6):885-895 (2006).

Recent research has shown that decadal-to-multidecadal (D2M) climate variability is associated with environmental changes that have important consequences for human activities, such as public health, water availability, frequency of hurricanes, and so forth. As scientists, how do we convert these relationships into decision support products useful to water managers, insurance actuaries, and others, whose principal interest lies in knowing when future climate regime shifts will likely occur that affect long-horizon decisions? Unfortunately, numerical models are far from being able to make deterministic predictions for future D2M climate shifts. However, the recent development of paleoclimate reconstructions of the Atlantic multidecadal oscillation (AMO) (Gray et al., 2004) and Pacific decadal oscillation (PDO) (MacDonald and Case, 2005) give us a viable alternative: to estimate probability distribution functions from long climate index series that allow us to calculate the probability of future D2M regime shifts. In this paper, we show how probabilistic projections can be developed for a specific climate mode--the AMO as represented by the Gray et al. (2004) tree ring reconstruction. The methods are robust and can be applied to any D2M climate mode for which a sufficiently long index series exists, as well as to the growing body of paleo-proxy reconstructions that have become available. The target index need not be a paleo-proxy calibrated against a climate index; it may profitably be calibrated against a specific resource of interest, such as stream flow or lake levels.

Enfield, D.B., S.-K. Lee, and C. Wang. How are large western hemisphere warm pools formed? Progress in Oceanography, 70(2-4):346-365 (2006).

During the boreal summer, the Western Hemisphere warm pool (WHWP) stretches from the eastern North Pacific to the tropical North Atlantic and is a key feature of the climate of the Americas and Africa. In the summers following nine El Ni�o events during 1950-2000, there have been five instances of extraordinarily large warm pools averaging about twice the climatological annual size. These large warm pools have induced a strengthened divergent circulation aloft and have been associated with rainfall anomalies throughout the western hemisphere tropics and subtropics and with more frequent hurricanes. However, following four other El Ni�o events large warm pools did not develop, such that the mere existence of El Ni�o during the boreal winter does not provide the basis for predicting an anomalously large warm pool the following summer. In this paper, we find consistency with the hypothesis that large warm pools result from an anomalous divergent circulation forced by sea surface temperature (SST) anomalies in the Pacific, the so-called atmospheric bridge. We also find significant explanations for why large warm pools do not always develop. If the El Ni�o event ends early in the eastern Pacific, the Pacific warm anomaly lacks the persistence needed to force the atmospheric bridge and the Atlantic portion of the warm pool remains normal. If SST anomalies in the eastern Pacific do not last much beyond February of the following year, then the eastern North Pacific portion of the warm pool remains normal. The overall strength of the Pacific El Ni�o does not appear to be a critical factor. We also find that when conditions favor a developing atmospheric bridge and the winter atmosphere over the North Atlantic conforms to a negative North Atlantic Oscillation (NAO) pattern (as in 1957-58 and 1968-69), the forcing is reinforced and the warm pool is stronger. On the other hand, if a positive NAO pattern develops the warm pool may remain normal even if other circumstances favor the atmospheric bridge, as in 1991-92. Finally, we could find little evidence that interactions internal to the tropical Atlantic are likely to mitigate for or against the formation of the largest warm pools, although they may affect smaller warm pool fluctuations or the warm pool persistence.

Esteban-Fernandez, D., J.R. Carswell, S. Frasier, P.S. Chang, P.G. Black, and F.D. Marks. Dual-polarized C- and Ku-band ocean backscatter response to hurricane-force winds. Journal of Geophysical Research, 111(C8):C08013, doi:10.1029/2005JC003048 (2006).

Airborne ocean backscatter measurements at C- and Ku-band wavelengths and H and V polarizations at multiple incidence angles obtained in moderate to very high wind speed conditions (25-65 m s^-1) during missions through several tropical cyclones are presented. These measurements clearly show that the normalized radar cross sections (NRCS) response stops increasing at hurricane-force winds for both frequency bands and polarizations except for high incidence angles at C-band and H polarization. The results also show the mean NRCS departing from a power law behavior for all the presented frequency bands, polarizations, and incidence angles, suggesting a reduction in the drag coefficient. The overall flattening of the azimuthal response of the NRCS is also very apparent in all cases. A new set of geophysical model functions (GMFs) at C- and Ku-band are developed from these direct ocean backscatter observations for ocean surface winds ranging from 25 to 65 m s^-1. The developed GMFs provide a much more accurate characterization of the NRCS versus wind speed and direction, and their implementation in operational retrieval algorithms from satellite-based scatterometer observations would result in better wind fields. The differences between these measurements and other currently available GMFs, such as QuikSCAT, NSCAT2, CMOD4, and CMOD5, are reported. The implementation of these GMFs in retrieval algorithms will result in better wind fields from satellite-based scatterometers measurements.

Etherton, B.J., C.-C. Wu, S.J. Majumdar, and S.D. Aberson. A comparison of targeting techniques for 2005 Atlantic tropical cyclones. Preprints, 27th Conference on Hurricanes and Tropical Meteorology, Monterey, CA, April 24-28, 2006. American Meteorological Society, Boston, 4 pp. (CD-ROM) (2006).

No abstract.

Evan, A.T., J.P. Dunion, J.A. Foley, A.K. Heidinger, and C.S. Velden. New evidence for a relationship between Atlantic tropical cyclone activity and African dust outbreaks. Geophysical Research Letters, 33(19):L19813, doi:10.1029/ 2006GL026408 (2006).

It is well known that Atlantic tropical cyclone activity varies strongly over time, and that summertime dust transport over the North Atlantic also varies from year to year, but any connection between tropical cyclone activity and atmospheric dust has been limited to a few case studies. Here we report new results that demonstrate a strong relationship between interannual variations in North Atlantic tropical cyclone activity and atmospheric dust cover as measured by satellite, for the years 1982-2005. While we cannot conclusively demonstrate a direct causal relationship, there appears to be robust link between tropical cyclone activity and dust transport over the Tropical Atlantic.

Feely, R.A., T. Takahashi, R.H. Wanninkhof, M.J. McPhaden, C.E. Cosca, S.C. Sutherland, and M.-E. Carr. Decadal variability of the air-sea CO₂ fluxes in the equatorial Pacific Ocean. Journal of Geophysical Research, 111(C8):C08S90, doi:10.1029/2005JC003129 (2006).

In order to determine the interannual and decadal changes in the air-sea carbon fluxes of the equatorial Pacific, we developed seasonal and interannual relationships between the fugacity of CO₂ (fCO₂) and sea surface temperature (SST) from shipboard data that were applied to high-resolution temperature fields deduced from satellite data to obtain high-resolution large-scale estimates of the regional fluxes. The data were gathered on board research ships from November 1981 through June 2004 between 95�W and 165�E. The distribution of fCO_2sw during five El Ni�o periods and four La Ni�a periods were documented. Observations made during the warm boreal winter-spring season and during the cooler boreal summer-fall season of each year enabled us to examine the interannual and seasonal variability of the fCO_2sw-SST relationships. A linear fit through all of the data sets yields an inverse correlation between SST and fCO_2sw, with both interannual and seasonal differences in slope. On average, the surface water fCO₂ in the equatorial region has been increasing at a rate similar to the atmospheric CO₂ increase. In addition, there appears to be a slight increase (~27%) in the outgassing flux of CO₂ after the 1997-1998 Pacific Decadal Oscillation (PDO) regime shift. Most of this flux increase is due to increase in wind speeds after the spring of 1998, although increases in fCO_2sw after 1998 are also important. These increases are coincident with the recent rebound of the shallow water meridional overturning circulation in the tropical and subtropical Pacific after the regime shift.

Feely, R.A., R. Wanninkhof, C.L. Sabine, G.C. Johnson, M.O. Baringer, J. Bullister, C.W. Mordy, and J.-Z. Zhang. Global repeat hydrographic/CO₂/tracer surveys in support of CLIVAR and global carbon cycle objectives: Carbon inventories and fluxes, pp. 196-205. In Annual Report on the State of the Ocean and the Ocean Observing System for Climate (FY-2005), J.M. Levy, D.M. Stanitski, and P. Arkin (eds.). NOAA Office of Climate Observation, Silver Spring, MD, 337 pp. (2006).

No abstract.

French, J.R., W.M. Drennan, J.A. Zhang, and P.G. Black. Direct airborne measurements of momentum flux in hurricanes. Preprints, 27th Conference on Hurricanes and Tropical Meteorology, Monterey, CA, April 24-28, 2006. American Meteorological Society, Boston, 6 pp. (CD-ROM) (2006).

No abstract.

Garzoli, S.L., R.L. Molinari, and R. Lumpkin. Surface drifter program, pp. 124-127. In Annual Report on the State of the Ocean and the Ocean Observing System for Climate (FY-2005), J.M. Levy, D.M. Stanitski, and P. Arkin (eds.). NOAA Office of Climate Observation, Silver Spring, MD, 337 pp. (2006).

No abstract.

Graber, H.C., V.J. Cardone, R.E. Jensen, D.N. Slinn, S.C. Hagen, A.T. Cox, M.D. Powell, and C. Grassl. Coastal forecasts and storm surge predictions for tropical cyclones: A timely partnership program. Oceanography, 19(1):130-141 (2006).

As more people and associated infrastructure concentrate along coastal areas, the United States is becoming more vulnerable to the impact of tropical cyclones. It is not surprising, especially after the past two hurricane seasons, that hurricanes are the costliest natural disasters because of the migration of the population towards the coast and the resulting changes in the national wealth density or revenue. A better understanding of both hurricane frequencies and intensities as they vary from year to year and their relation to changes in damages is of great interest to scientists, public and private-decision makers, and the general public. The estimation of tropical-cyclone-generated waves and surge in coastal waters and the nearshore zone is of critical importance to the timely evacuation of coastal residents, and the assessment of damage to coastal property in the event that a storm makes landfall. The model predictions of waves and storm surge in coastal waters are functionally related and both depend on the reliability of the atmospheric forcing. Hurricane Georges (1998), Ivan (2004), and Katrina and Wilma (2005) are excellent examples of intense tropical cyclones with numerous landfalls and unexpected changes in intensity and movement. Although there are no perfect predictions of the time and location of landfall and the intensity and size of the storm, we are able to forecast wind strength, storm-wave height, and surge levels that are expected along the official track from the National Hurricane Center (NHC) as well as from an ensemble of about a dozen track forecasts that would bracket the results from the least to worst conditions. The variability of these parameters, if known for different forecast tracks, could positively impact the advisories. To be effective and useful, a critical component of any forecast system is its timeliness.

Graves, L.P., J.C. McWilliams, and M.T. Montgomery. Vortex evolution due to straining: A mechanism for dominance of strong, interior anticyclones. Geophysical and Astrophysical Fluid Dynamics, 100(3):151-183 (2006).

In this article we address two questions: Why do freely evolving vortices weaken on average, even when the viscosity is very small? Why, in the fluid's interior, away from vertical boundaries and under the influence of Earth's rotation and stable density stratification, do anticyclonic vortices become dominant over cyclonic ones when the Rossby number and deformation radius are finite? The context for answering these questions is a rotating, conservative, Shallow-water model with Asymmetric and Gradient-wind Balance approximations. The controlling mechanisms are vortex weakening under straining deformation (with a weakening that is substantially greater for strong cyclones than strong anticyclones) followed by a partially compensating vortex strengthening during a relaxation phase dominated by Vortex Rossby Waves (VRWs) and their eddy-mean interaction with the vortex. The outcome is a net, strain-induced vortex weakening that is greater for cyclones than anticyclones when the deformation radius is not large compared to the vortex radius and the Rossby number is not small. Furthermore, when the exterior strain flow is sustained, the vortex changes also are sustained: for small Rossby number (i.e., the quasigeostrophic limit, QG), vortices continue to weaken at a relatively modest rate, but for larger Rossby number, cyclones weaken strongly and anticyclones actually strengthen systematically when the deformation radius is comparable to the vortex radius. The sustained vortex changes are associated with strain-induced VRWs on the periphery of the mean vortex. It therefore seems likely that, in a complex flow with many vortices, anticyclonic dominance develops over a sequence of transient mutual straining events due to the greater robustness of anticyclones (and occasionally their net strengthening).

Halliwell, G.R., L.K. Shay, E.W. Uhlhorn, S.D. Jacob, and O.M. Smedstad. Improving ocean state initialization in coupled tropical cyclone forecast models. Preprints, 27th Conference on Hurricanes and Tropical Meteorology, Monterey, CA, April 24-28, 2006. American Meteorological Society, Boston, 4 pp. (CD-ROM) (2006).

No abstract.

Hausman, S.A., K.V. Ooyama, and W.H. Schubert. Potential vorticity structure of simulated hurricanes. Journal of the Atmospheric Sciences, 63(1):87-108 (2006).

To better understand the processes involved in tropical cyclone development, the authors simulate an axisymmetric tropical-cyclone-like vortex using a two-dimensional model based on nonhydrostatic dynamics, equilibrium thermodynamics, and bulk microphysics. Sensitivity experiments reveal that the simulated cyclones are sensitive to the effects of ice, primarily through the reduced fall velocity of precipitation above the freezing level rather than through the latent heat of fusion, and to the effects of vertical entropy transport by precipitation.

Hendee, J.C., E.R. Stabenau, L. Florit, D. Manzello, and C. Jeffris. Infrastructure and capabilities of a near real-time meteorological and oceanographic in situ instrumented array and its role in marine environmental decision support. In Remote Sensing of Aquatic Coastal Ecosystem Processes, L.L. Richardson and E.F. LeDrew (eds.). Springer Verlag, Volume 9, 135-156 (2006).

No abstract.

Hendricks, E.A., and M.T. Montgomery. Rapid scan views of convectively generated mesovortices in sheared Tropical Cyclone Gustav. Weather and Forecasting, 21(6):1041-1050 (2006).

On 9-10 September 2002, multiple mesovortices were captured in great detail by rapid scan visible satellite imagery in subtropical, then later, Tropical Storm Gustav. These mesovortices were observed as low-level cloud swirls while the low-level structure of the storm was exposed due to vertical shearing. They are shown to form most plausibly via vortex tube stretching associated with deep convection; they become decoupled from the convective towers by vertical shear; they are advected with the low-level circulation; finally they initiate new hot towers on their boundaries. Partial evidence of an axisymmetrizing mesovortex and its hypothesized role in the parent vortex spinup is presented. Observations from the mesoscale and synoptic scale are synthesized to provide a multiscale perspective of the intensification of Gustav that occurred on 10 September. The most important large-scale factors were the concurrent relaxation of the 850-200 hPa-deep layer vertical wind shear from 10-15 to 5-10 m s^-1 and movement over pockets of very warm sea surface temperatures (approximately 29.5°-30.5°C). The mesoscale observations are not sufficient alone to determine the precise role of the deep convection and mesovortices in the intensification. However, qualitative comparisons are made between the mesoscale processes observed in Gustav and recent full-physics and idealized numerical simulations to obtain additional insight.

Hood, R.E., E. Zipser, G.M. Heymsfield, R. Kakar, J. Halverson, R.F. Rogers, and M.L. Black. Overview of the field phase of the NASA Tropical Cloud Systems and Processes (TCSP) Experiment. Preprints, 27th Conference on Hurricanes and Tropical Meteorology, Monterey, CA, April 24-28, 2006. American Meteorological Society, Boston, 3 pp. (CD-ROM) (2006).

No abstract.

Hood, R.E., R.J. Blakeslee, M. Goodman, D.J. Cecil, D.M. Mach, F.J. LaFontaine, G.M. Heymsfield, F.D. Marks, and E.J. Zipser. Classification of tropical oceanic precipitation using high altitude aircraft microwave and electric field measurements. Journal of the Atmospheric Sciences, 63(1):218-233 (2006).

During the 1998 and 2001 hurricane seasons of the western Atlantic Ocean and Gulf of Mexico, the Advanced Microwave Precipitation Radiometer (AMPR), the ER-2 Doppler (EDOP) radar, and the Lightning Instrument Package (LIP) were flown aboard the NASA ER-2 high-altitude aircraft as part of the Third Convection and Moisture Experiment (CAMEX-3) and the Fourth Convection and Moisture Experiment (CAMEX-4). Several hurricanes, tropical storms, and other precipitation systems were sampled during these experiments. An oceanic rainfall screening technique has been developed using AMPR passive microwave observations of these systems collected at frequencies of 10.7, 19.35, 37.1, and 85.5 GHz. This technique combines the information content of the four AMPR frequencies regarding the gross vertical structure of hydrometeors into an intuitive and easily executable precipitation mapping format. The results have been verified using vertical profiles of EDOP reflectivity and lower-altitude horizontal reflectivity scans collected by the NOAA WP-3D Orion radar. Matching the rainfall classification results with coincident electric field information collected by the LIP readily identifies convective rain regions within the precipitation fields. This technique shows promise as a real-time research and analysis tool for monitoring vertical updraft strength and convective intensity from airborne platforms such as remotely operated or uninhabited aerial vehicles. The technique is analyzed and discussed for a wide variety of precipitation types using the 26 August 1998 observations of Hurricane Bonnie near landfall.

Houze, R.A., S.S. Chen, W.-C. Lee, R.F. Rogers, J.A. Moore, G.J. Stossmeister, M.M. Bell, J.L. Cetrone, W. Zhao, and S.R. Brodzik. The Hurricane Rainband and Intensity Experiment: Observations and modeling of Hurricanes Katrina, Ophelia, and Rita (2005). Bulletin of the American Meteorological Society, 87(11):1503-1521 (2006).

The Hurricane Rainband and Intensity Change Experiment (RAINEX) used three P3 aircraft aided by high-resolution numerical modeling and satellite communications to investigate the 2005 Hurricanes Katrina, Ophelia, and Rita. The aim was to increase the understanding of tropical cyclone intensity change by interactions between a tropical cyclone's inner core and rainbands. All three aircraft had dual-Doppler radars, with the Electra Doppler Radar (ELDORA) on board the Naval Research Laboratory's P3 aircraft, providing particularly detailed Doppler radar data. Numerical model forecasts helped plan the aircraft missions, and innovative communications and data transfer in real time allowed the flights to be coordinated from a ground-based operations center. The P3 aircraft released approximately 600 dropsondes in locations targeted for optimal coordination with the Doppler radar data, as guided by the operations center. The storms were observed in all stages of development, from tropical depression to category 5 hurricane. The data from RAINEX are readily available through an online Field Catalog and RAINEX Data Archive. The RAINEX data-set is illustrated in this article by a preliminary analysis of Hurricane Rita, which was documented by multiaircraft flights on five days (1) while a tropical storm, (2) while rapidly intensifying to a category 5 hurricane, (3) during an eye-wall replacement, (4) when the hurricane became asymmetric upon encountering environmental shear, and (5) just prior to landfall.

Huang, X.-L., and J.-Z. Zhang. Surfactant-sensitized malachite green method for trace determination of orthophosphate in aqueous solution. Analytica Chimica Acta, 580(1):55-67 (2006).

A surfactant-sensitized spectrophotometric method for determination of trace orthophosphate has been developed using anion surfactant (Ultrawet 60 L) with molybdate and malachite green in low acidic medium (pH_T 1.0). The method detection limit (3x standard deviation of blank, n = 10) was 8 nM, and the calibration curve was linear over a range of 10-400 nM (r² = 0.997). The molar absorptivity was 1.26 x 10⁵ L mol^-1 cm^-1 at 600 nm with the background correction at 530 nm. The precision of method was 3.4% at 50 nM and 2.4% at 100 nM orthophosphate (n = 10). The hydrolysis of eight organic phosphorus and polyphosphate compounds was less than 2% of the total phosphorus present (5-10 µM). This method showed less arsenate interference than previous methods, with only 3% even in the presence of orthophosphate in the samples. No interference of silicate up to 40 µM was observed. Background anions (in an order of SO₄^2- > NO₃^- > Cl^-) have greater effects than cations (Ca²⁺ > Mg²⁺ > Na⁺) on the reagent blank and the molar absorptivity of the color product.

Jaimes, B., L.K. Shay, E.W. Uhlhorn, T.M. Cook, J. Brewster, G.R. Halliwell, and P.G. Black. Influence of Loop Current ocean heat content on Hurricanes Katrina, Rita, and Wilma. Preprints, 27th Conference on Hurricanes and Tropical Meteorology, Monterey, CA, April 24-28, 2006. American Meteorological Society, Boston, 4 pp. (CD-ROM) (2006).

No abstract.

Jiang, H., P.G. Black, E.J. Zipser, F.D. Marks, and E.W. Uhlhorn. Validation of rain-rate estimation in hurricanes from the Stepped Frequency Microwave Radiometer: Algorithm correction and error analysis. Journal of the Atmospheric Sciences, 63(1):252-267 (2006).

Simultaneous observations by the lower fuselage (LF) radar, the tail (TA) radar, and the Stepped Frequency Microwave Radiometer (SFMR) on board the NOAA WP-3D aircraft are used to validate the rainfall rate estimates from microwave emission measurements of SFMR in tropical cyclones. Data collected in Hurricane Bonnie (1998) and Hurricane Humberto (2001) with a total of 820 paired samples are used in the comparisons. The SFMR 10-s path-integrated rain rates are found to have an overestimate in light rain and an underestimate in heavy rain relative to radar rainfall estimates. Examination of the existing SFMR algorithm shows that the coefficient should be changed in the attenuation-rain-rate relationship used in the inversion algorithm. After this correction, a linear regression result with a correlation coefficient of 0.8 and a slope close to 1 is obtained. But an overall high bias of 5 mm h^-1 of the SFMR rainfall estimate relative to radar is also found. The error analysis shows that the bias is nearly independent of rain type, a result confirming Jorgensen and Willis' conclusion that the drop size distributions between convective and stratiform rain in hurricanes are similar. It is also shown that the bias is a weak function of wind speed, as well as a weak inverse function of radial distance to the hurricane center. Temperature dependence has been ruled out as the main explanation. After doing sensitivity tests, the authors conclude that the bias results from a combination of two factors: an underestimate of the freezing-level height and a downward increase of radar reflectivity in the high wind regions. If the true downward increase is 1-2 dBZ km^-1, a 0.5-km underestimate of the freezing-level height could account for up to a 3-5 mm h^-1 bias.

Johnson, G.C., S. Levitus, J.M. Lyman, C. Schmid, and J.K. Willis. Ocean heat content variability, pp. 74-84. In Annual Report on the State of the Ocean and the Ocean Observing System for Climate (FY-2005), J.M. Levy, D.M. Stanitski, and P. Arkin (eds.). NOAA Office of Climate Observation, Silver Spring, MD, 337 pp. (2006).

Upper ocean heat content is important in understanding and predicting climate phenomena such hurricanes, El Niño, and global warming. This quantity is estimated globally from in situ and satellite data for 2005. The results are compared against estimates from 2004, the past decade, and the past 50 years. The widespread deployment of Argo Project floats starting in 2003 greatly reduces uncertainties in global yearly averages of upper ocean heat content. Interannual variability of the seasonal cycle in mixed layer thickness and temperature (thus mixed layer heat content) is discussed in the tropical Atlantic.

Kakar, R., F.D. Marks, G. McFarquhar, and R. Hood. Preface. Journal of the Atmospheric Sciences, 63(1):3-4 (2006).

No abstract.

Kaplan, J., and M. DeMaria. Estimating the likelihood of rapid intensification in the Atlantic and east Pacific basins using SHIPS model data. Preprints, 27th Conference on Hurricanes and Tropical Meteorology, Monterey, CA, April 24-28, 2006. American Meteorological Society, Boston, 4 pp. (CD-ROM) (2006).

No abstract.

Katsaros, K.B., R.T. Pinker, A. Bentamy, J.A. Carton, W.M. Drennan, and A.M. Mestas-Nunez. Net air-sea flux estimates for the tropical and subtropical Atlantic Ocean based on satellite data. Proceedings, 3rd MSG RAO Workshop, Helsinki, Finland, June 12-16, 2006. European Space Agency, ESA SP-619, 77-82 (2006).

The objective of our work is to estimate the net heat exchange across the air-sea interface in the tropical and subtropical Atlantic Ocean using mainly satellite data. The net flux and the various terms will be used to study the processes in the upper ocean related to changes in sea surface temperature (SST). This variable influences atmospheric circulations and is indicative of upper ocean circulations in this area. We employ data from METEOSAT-7 and 8 and from the Special Sensor Microwave/Imager (SSM/I) for the shortwave and long-wave radiative fluxes and for estimates of SST. For turbulent flux calculations, we use the bulk aerodynamic method with satellite estimates for wind speed and atmospheric humidity and temperature. We expect our work to shed light on rainfall regimes in Africa and South America and on the changes and slope of the tropical thermocline structure in the Atlantic Ocean.

Kourafalou, V.H., R.S. Balotro, G. Peng, T.N. Lee, E. Johns, P.B. Ortner, A. Wallcraft, and T. Townsend. Seasonal variability of circulation and salinity around Florida Bay and the Florida Keys: SoFLA-HYCOM results and comparison to in-situ data. University of Miami Technical Report, RSMAS 2006-04, 102 pp. (2006).

No abstract.

Lavin, M.F., P.C. Fiedler, J.A. Amador, L.T. Ballance, J. Farber-Lorda, and A.M. Mestas-Nunez. A review of eastern tropical Pacific oceanography: Summary. Progress in Oceanography, 69(2-4):391-398 (2006).

The collection of articles in this volume reviewing eastern tropical Pacific oceanography is briefly summarized, and updated references are given. The region is an unusual biological environment as a consequence of physical characteristics and patterns of forcing, including a strong and shallow thermocline, the ITCZ and coastal wind jets, equatorial upwelling, the Costa Rica Dome, eastern boundary and equatorial current systems, low iron input, inadequate ventilation of subthermocline waters, and dominance of ENSO-scale temporal variability. Remaining unanswered questions are presented.

Lee, K., L.T. Tong, F.J. Millero, C.L. Sabine, A.G. Dickson, C. Goyet, G.-H. Park, R. Wanninkhof, R.A. Feely, and R.M. Key. Global relationships of total alkalinity with salinity and temperature in surface waters of the world's oceans. Geophysical Research Letters, 33(19):L19605, doi:10.1029/2006GL027207 (2006).

A simple function of sea surface salinity (SSS) and temperature (SST) in the form A_T = a + b (SSS - 35) + c (SSS - 35)² + d (SST - 20) + e (SST - 20)² fits surface total alkalinity (A_T) data for each of five oceanographic regimes within an area-weighted uncertainty of ±8.1 µmol kg^-1 (1 sigma). Globally coherent surface A_T data (n = 5,692) used to derive regional correlations of A_T with SSS and SST were collected during the global carbon survey in the 1990s. Such region-specific A_T algorithms presented herein enable the estimation of the global distribution of surface AT when observations of SSS and SST are available.

Lee, T.N., E. Johns, N. Melo, R.H. Smith, P.B. Ortner, and N. Smith. On Florida Bay hypersalinity and water exchange. Bulletin of Marine Science, 79(2):301-327 (2006).

Florida Bay is made up of a collection of shallow basins separated by mud banks and mangrove islands situated between the Florida mainland and the Florida Keys. The bay is located downstream of the Everglades discharge that has been altered over the past century due to South Florida land use practices, leading to reduced water delivery to Florida Bay and elevated salinities. The reduced freshwater flow has had the strongest impacts in the north-central region of the bay, in the vicinity of Whipray basin (WB), where extreme hypersalinity can develop along with degradation of water quality and seagrass die-off. We use direct measurement of water exchange between Whipray and surrounding regions for dry and wet seasons of 2001 together with detailed salinity surveys, sea level measurements, and freshwater flux estimates to evaluate water and salt balances, and to estimate basin water renewal rates and residence times. Water renewal of WB is strongly regulated by local wind forcing. Winds toward the east from the passage of cold fronts during the winter/spring dry season resulted in a mean eastward flow through Whipray of 11 m³ s^-1, with inflows over the wide western mud banks, and outflows through the eastern and southern channels. Conversely, winds toward the southwest and west typical of the summer/fall wet season produced a mean throughflow of 3 m³ s^-1, with inflows through the eastern channels and outflows over the western banks. The time required for complete renewal of WB waters is estimated at 6-12 mo. Water balances are used to estimate a weak seasonal average groundwater input to Whipray of 1.7 m³ s^-1 during the dry season and a negative groundwater flow or downwelling of -4.7 m³ s^-1 for the wet season. Hypersalinity development was found to be caused by the combination of reduced freshwater inputs during the dry season combined with weak basin water renewal rates. Hypersalinity development could be greatly reduced by diversion of freshwater to WB via McCormick Creek during dry seasons.

Lentini, C., G.J. Goni, and D.B. Olson. Investigation of Brazil Current rings in the confluence region. Journal of Geophysical Research, 111(C6):C06013, doi:10.1029/2005JC002988 (2006).

TOPEX/Poseidon-derived along track SHA, climatological temperature, and salinity fields were used within a two-layer scheme to estimate the depth of the 8°C isotherm in the southwestern Atlantic. These fields were used to monitor the formation and characteristics of the Brazil Current warm-core anticyclonic rings shed by the first meander trough after poleward excursions of the Brazil Current (BC). Results reveal that 40 warm-core rings were shed by the BC between January 1993 and October 1998. The observed lifetime ranges between 1 and 4 months, with a mean value of approximately 2 months. At any given time, two to three anticyclonic rings coexisted in the Brazil-Malvinas confluence region. Most of the rings drifted southward without coalescing with their parent current. Only four rings were identified as being reabsorbed by the BC front after they were shed. No evidence of propagation or absorption of these anticyclones into the eastern limb of the subtropical gyre was observed. These rings have a mean horizontal length scale of 55 km, mean upper-layer thickness of 260 m, and mean translation speed of 10 km d^-1. Volume anomaly and available potential energy computations showed a mean value of 3.6 x 10¹² m³ and 2.5 x 10¹⁵ J, respectively. The upper layer transport of the BC was also computed, and a relationship between variations in the southward transport and ring shedding activity was examined. Computation of the heat flux anomaly of the BC rings is estimated to be approximately 0.045 PW per annum. Compilation of these results indicates that warm-core rings created by meandering boundary current extensions in different regions are generally similar.

Li, Y.-H., L. Menviel, and T.-H. Peng. Nitrate deficits by nitrification and denitrification processes in the Indian Ocean. Deep-Sea Research, Part I, 53(1):94-110 (2006).

The three-end-member mixing model of Li and Peng [Latitudinal change of remineralization ratios in the oceans and its implication for nutrient cycles, Global Biogeochemical Cycles, 16:1130-1145] was applied to the World Ocean Circulation Experiment (WOCE) data from Indian Ocean to obtain additional estimates on the remineralization ratios (P\N\C_org\-O₂) of organic matter in the oxygenated regions. The results show systematic changes of the remineralization ratios with latitude and depth in the Indian Ocean. The average remineralization ratios for Indian warm water masses (potential temperature theta > ~10°C) are P\N\C_org\-O₂ = 1\(15.6±0.7)\(110±9)\(159±8). These are comparable to the traditional Redfield ratios (P\N\C_org\-O₂ = 1\16\106\138), and are in good agreement with Anderson's [On the hydrogen and oxygen content of marine phytoplankton, Deep-Sea Research, Part I, 42:1675-1680] values of P\N\C_org\-O₂ = 1\16\106\150 within the given uncertainties. Separation of nitrate deficits resulting from aerobic partial nitrification (dN) and anaerobic denitrification (dN") processes using empirical equations is shown to be useful and consistent with other observations. The dN maximum coincides with the phosphate and nitrate maximums, lies within the oxycline below the oxygen minimum zone, and is in contact with the continental slope sediments. The dN maximum lies within the oxygen minimum zone with O₂ < ~2 µmol/kg, is in contact with shelf or upper slope sediments, and is always associated with a secondary nitrite maximum in the water column. The spatial extent of dN is much larger than that of dN". The low N/P remineralization ratio (<15) for deep waters (theta < ~10°C) and the dN maximum in the lower oxycline can be best explained by the partial conversion of organic nitrogen into N₂, N₂O, and NO by yet unidentified bacteria during oxidation of organic matter. These bacteria may have evolved in a low oxygen and high nitrate environment to utilize both oxygen and nitrate as terminal electron acceptors during oxidation of organic matter (i.e., the partial nitrification hypothesis). Direct proof is urgently needed.

Lindberg, W.J., T.K. Frazer, K.M. Portier, F. Vose, J. Loftin, D.J. Murie, D.M. MasonN, B. Nagy, and M.K. Hart. Density-dependent habitat selection and performance by a large mobile reef fish. Ecological Applications, 16(2):731-746 (2006).

Many exploited reef fish are vulnerable to over-fishing because they concentrate over hard-bottom patchy habitats. How mobile reef fish use patchy habitat, and the potential consequences on demographic parameters, must be known for spatially explicit population dynamics modeling, for discriminating Essential Fish Habitat (EFH) and for effectively planning conservation measures (e.g., marine protected areas, stock enhancement and artificial reefs). Gag, Mycteroperca microlepis, is an ecologically and economically important warm-temperate grouper in the southeastern USA, with behavioral and life history traits conducive to large-scale field experiments. The Suwannee Regional Reef System (SRRS) was built of standard habitat units (SHUs) in 1991-1993 to manipulate and control habitat patchiness and intrinsic habitat quality, and thereby test predictions from habitat selection theory. Colonization of the SRRS by gag over the first 6 years showed significant interactions of SHU size, spacing and reef age; with trajectories modeled using a quadratic function for closely spaced SHUs (25 m) and a linear model for widely spaced SHUs (225 m), with larger SHUs (16 standardized cubes) accumulating significantly more gag faster than smaller 4-cube SHUs (mean = 72.5 gag/16-cube SHU at 225-m spacing by year 6, compared to 24.2 gag/4-cube SHU for same spacing and reef age). Residency times (mean = 9.8 mos.), indicative of choice and measured by ultrasonic telemetry (1995-1998), showed significant interaction of SHU size and spacing consistent with colonization trajectories. Average relative weight (W_r) and incremental growth were greater on smaller than larger SHUs (mean W_r = 104.2 versus 97.7; incremental growth differed by 15%), contrary to patterns of abundance and residency. Experimental manipulation of shelter on a subset of SRRS sites (2000-2001) confirmed our hypothesis that shelter limits local densities of gag, which, in turn, regulates their growth and condition. Density-dependent habitat selection (DDHS) for shelter and individual growth dynamics were therefore interdependent ecological processes that help to explain how patchy reef habitat sustains gag production. Moreover, gag selected shelter at the expense of maximizing their growth. Thus, mobile reef fishes could experience density-dependent effects on growth, survival, and/or reproduction (i.e., demographic parameters) despite reduced stock sizes as a consequence of fishing.

Liu, Q., M. Surgi, S. Lord, W.-S. Wu, D. Parrish, S. Gopalakrishnan, J. Waldrop, and J.F. Gamache. Hurricane initialization in HWRF model. Preprints, 27th Conference on Hurricanes and Tropical Meteorology, Monterey, CA, April 24-28, 2006. American Meteorological Society, Boston, 2 pp. (CD-ROM) (2006).

No abstract.

Lonfat, M., R.F. Rogers, F.D. Marks, T. Marchok, and A. Boissonnade. The effect of shear and topography on rainfall forecasting with R-CLIPER. Preprints, 27th Conference on Hurricanes and Tropical Meteorology, Monterey, CA, April 24-28, 2006. American Meteorological Society, Boston, 2 pp. (CD-ROM) (2006).

No abstract.

Lueger, H., R.H. Wanninkhof, D.W.R. Wallace, and A. Kortzinger. CO₂ fluxes in the subtropical and subarctic North Atlantic based on measurements from a volunteer observing ship. Journal of Geophysical Research, 111(6):C06024, doi:10.1029/2005JC003101 (2006).

Surface seawater pCO₂ and related parameters were measured at high frequency onboard the volunteer observing ship M/V Falstaff in the North Atlantic Ocean between 36° and 52°N. Over 90,000 data points were used to produce monthly CO₂ fluxes for 2002/2003. The air-sea CO₂ fluxes calculated by two different averaging schemes were compared. The first approach used gas transfer velocity determined from wind speed retrieved at the location of the ship and called colocated winds, while for the second approach a monthly averaged gas transfer velocity was calculated from the wind for each grid pixel including the variability in wind. The colocated wind speeds determined during the time of passage do not capture the monthly wind speed variability of the grid resulting in fluxes that were 47% lower than fluxes using the monthly averaged wind products. The Falstaff CO₂ fluxes were in good agreement with a climatology using averaged winds. Over the entire region they differed by 2-5%, depending on the time-dependent correction scheme to account for the atmospheric in increase in pCO₂. However, locally the flux differences between the ship measurements and the climatology were greater, especially in regions north of 45°N, like the eastern sector. A comparison of two wind speed products showed that the annual CO₂ sink is 4% less when using 6 hourly NCEP/NCAR wind speeds compared to the QuikSCAT wind speed data.

Lumpkin, R., and G.J. Goni. Evaluating the ocean observing system: Performance measurement for heat storage, pp. 263-264. In Annual Report on the State of the Ocean and the Ocean Observing System for Climate (FY-2005), J.M. Levy, D.M. Stanitski, and P. Arkin (eds.). NOAA Office of Climate Observation, Silver Spring, MD, 337 pp. (2006).

No abstract.

Lumpkin, R., and G.J. Goni. Global oceans: Surface currents. In State of the Climate in 2005, K.A. Shein, A.M. Waple, H.J. Diamond, and J.M. Levy (eds.). Bulletin of the American Meteorological Society, 87(6):S25-S26 (2006).

No abstract.

Lumpkin, R., and G.J. Goni. Surface currents, pp. 61-67. In Annual Report on the State of the Ocean and the Ocean Observing System for Climate (FY-2005), J.M. Levy, D.M. Stanitski, and P. Arkin (eds.). NOAA Office of Climate Observation, Silver Spring, MD, 337 pp. (2006).

Surface currents are measured in-situ by an array of 14 primarily tropical moored buoys and a global array of approximately 1250 drifters. Current variations can also be estimated from satellite altimetry. In 2005, westward current anomalies of nearly 20 cm/s were observed in the equatorial Pacific between 120°W and the dateline, with strong monthly anomalies in the western Pacific associated with equatorial wave passage. In the Atlantic Ocean, the Florida Current and Gulf Stream were close to their long-term climatological strengths.

Majumdar, S.J., S.D. Aberson, C.H. Bishop, R. Buizza, M.S. Peng, and C.A. Reynolds. A comparison of adaptive observing guidance for Atlantic tropical cyclones. Monthly Weather Review, 134(9):2354-2372 (2006).

Airborne adaptive observations have been collected for more than two decades in the neighborhood of tropical cyclones, to attempt to improve short-range forecasts of cyclone track. However, only simple subjective strategies for adaptive observations have been used, and the utility of objective strategies to improve tropical cyclone forecasts remains unexplored. Two objective techniques that have been used extensively for midlatitude adaptive observing programs, and the current strategy based on the ensemble deep-layer mean (DLM) wind variance, are compared quantitatively using two metrics. The ensemble transform Kalman filter (ETKF) uses ensembles from NCEP and the ECMWF. Total-energy singular vectors (TESVs) are computed by the ECMWF and the Naval Research Laboratory, using their respective global models. Comparisons of 78 guidance products for 2-day forecasts during the 2004 Atlantic hurricane season are made, on both continental and localized scales relevant to synoptic surveillance missions. The ECMWF and NRL TESV guidance identifies similar large-scale target regions in 90% of the cases, but are less similar to each other in the local tropical cyclone environment (56% of the cases) with a more stringent criterion for similarity. For major hurricanes, all techniques usually indicate targets close to the storm center. For weaker tropical cyclones, the TESV guidance selects similar targets to those from the ETKF (DLM wind variance) in only 30% (20%) of the cases. ETKF guidance using the ECMWF ensemble is more like that provided by the NCEP ensemble (and DLM wind variance) for major hurricanes than for weaker tropical cyclones. Minor differences in these results occur when a different metric based on the ranking of fixed storm-relative regions is used.

Manzello, D., J.C. Hendee, D. Ward, and Z. Hillis-Starr. An evaluation of environmental parameters coincident with the partial bleaching event in St. Croix, U.S. Virgin Islands (2003). Proceedings, 10th International Coral Reef Symposium, Okinawa, Japan, June 28-July 2, 2004. International Society for Coral Reef Studies, 709-717 (2006).

A partial bleaching event was reported in September and October 2003 in St. Croix, yet no bleaching alert was produced by the expert system software dubbed the Coral Reef Early Warning System (CREWS). This presents an opportunity for refining the modeling and predictive success of the CREWS software specifically for the St. Croix site by examination of the pertinent environmental parameters (sea temperature, wind speeds, irradiance) associated with the 2003 bleaching event. Elevated sea temperatures were likely the primary catalyst of bleaching and were coincident with dampened wind speeds. The least attenuation (greatest penetration) of UVB occurred during October when bleaching was most severe, but was variable. A nearly parallel trend with wind speed and UVB penetration was found and supports the hypothesis that the attenuation of UVB into the water column is controlled by CDOM concentrations, which are elevated due to wind-driven mixing.

Marchok, T., R.F. Rogers, and R. Tuleya. New methods for evaluating rainfall forecasts from operational models for landfalling tropical cyclones. Preprints, 27th Conference on Hurricanes and Tropical Meteorology, Monterey, CA, April 24-28, 2006. American Meteorological Society, Boston, 5 pp. (CD-ROM) (2006).

No abstract.

McArthur,C.J., S.J. Stamates, and J.R. Proni. Review of the real-time current monitoring requirement for the Miami Ocean Dredged Material Disposal Site. NOAA Technical Memorandum, OAR AOML-95, 13 pp. (2006).

The Environmental Protection Agency manages an Ocean Dredged Material Disposal Site (ODMDS) offshore Miami, Florida. To protect coral reefs west of the ODMDS, use of the disposal site is restricted during periods of reef-directed currents. In 1995, the National Oceanic and Atmospheric Administration developed a real-time current monitoring program for the Corps of Engineers for disposal of material from the Phase I Deepening Project at the Port of Miami. The program consists of a system for measuring and reporting currents at the ODMDS in real-time and a set of evaluation criteria for determining when disposal can occur. The initial system deployments resulted in three years of data from 1995 through 2000. This data is reviewed and analyzed to assess the impacts on dredging operations and the potential or disposal plume interaction with the nearby coral reefs.

McFarquhar, G.M., H. Zhang, G.M. Heymsfield, J.B. Halverson, R.E. Hood, J. Dudhia, and F.D. Marks. Factors affecting the evolution of Hurricane Erin (2001) and the distributions of hydrometeors: Role of microphysical processes. Journal of the Atmospheric Sciences, 63(1):127-150 (2006).

Fine-resolution simulations of Hurricane Erin are conducted using the fifth-generation Pennsylvania State University-NCAR Mesoscale Model (MM5) to investigate roles of thermodynamic, boundary layer, and microphysical processes on Erin's structure and evolution. Choice of boundary layer scheme has the biggest impact on simulations, with the minimum surface pressure (P_min) averaged over the last 18 h (when Erin is relatively mature) varying by over 20 hPa. Over the same period, coefficients used to describe graupel fall speeds (V_g) affect P_min by up to 7 hPa, almost equivalent to the maximum 9-hPa difference between microphysical parameterization schemes; faster V_g and schemes with more hydrometeor categories generally give lower P_min. Compared to radar reflectivity factor (Z) observed by the NOAA P-3 lower fuselage radar and the NASA ER-2 Doppler radar (EDOP) in Erin, all simulations overpredict the normalized frequency of occurrence of Z larger than 40 dBZ and underpredict that between 20 and 40 dBZ near the surface; simulations overpredict Z larger than 25 to 30 dBZ and underpredict that between 15 and 25 or 30 dBZ near the melting layer, the upper limit depending on altitude. Brightness temperatures (T_b) computed from modeled fields at 37.1- and 85.5-GHz channels that respond to scattering by graupel-size ice show enhanced scattering, mainly due to graupel, compared to observations. Simulated graupel mixing ratios are about 10 times larger than values observed in other hurricanes. For the control run at 6.5 km averaged over the last 18 simulated hours, Doppler velocities computed from modeled fields (V_dop) greater than 5 m s^-1 make up 12% of Erin's simulated area for the base simulation but less than 2% of the observed area. In the eyewall, 5% of model updrafts above 9 km are stronger than 10 m s^-1, whereas statistics from other hurricanes show that 5% of updrafts are stronger than only 5 m s^-1. Variations in distributions of Z, vertical motion, and graupel mixing ratios between schemes are not sufficient to explain systematic offsets between observations and models. A new iterative condensation scheme, used with the Reisner mixed-phase microphysics scheme, limits unphysical increases of equivalent potential temperature associated with many condensation schemes and reduces the frequency of Z larger than 50 dBZ, but has minimal effect on Z below 50 dBZ, which represent 95% of the modeled hurricane rain area. However, the new scheme changes the Erin simulations in that 95% of the updrafts are weaker than 5 m s^-1 and P_min is up to 12 hPa higher over the last 18 simulated hours.

McGillis, W.R., and R.H. Wanninkhof. Aqueous CO₂ gradients for air-sea flux estimates. Marine Chemistry, 98(1):100-108 (2006).

The concentration of gaseous carbon dioxide (CO₂) in surface seawater is a fundamental control on the CO₂ flux between the ocean and atmosphere. However, the concentration gradient in the aqueous mass boundary layer determines the magnitude and direction of the flux. The gradients of CO₂ in the aqueous mass boundary layer cannot be measured directly and are usually inferred from partial pressures or fugacities of CO₂ (fCO₂) in the air and water. In addition to the fCO₂, the temperatures at the top and bottom of the aqueous mass boundary layer must be known to determine the thermodynamic driving force of CO₂ gas transfer. Expressing the gradient in terms of the aqueous CO₂ concentration, [CO_2aq], also avoids some conceptual ambiguities. In particular, expressing the CO₂ as a fugacity, which is defined relative to the gas phase, when the gas exchange rate is controlled in the aqueous mass boundary layer often leads to errors in interpretation with respect to changes in boundary layer temperature. As a result, the enhanced CO₂ flux caused by the cool skin effect appears to be overestimated. Apart from the difficulties estimating the temperature at the top and bottom of the aqueous mass boundary layer, the temperature dependence of solubility and fugacity of CO₂ is uncertain to the degree that it can bias air-sea CO₂ flux estimates. The CO_2aq at the surface, [CO_2aq0], is at equilibrium with the atmospheric CO₂ level. As [CO_2aq0] is strongly temperature dependent, it will be significantly higher at high latitude compared to low latitude, while atmospheric CO₂ levels show much less of a gradient.

Meinen, C.S., M.O. Baringer, and S.L. Garzoli. Variability in Deep Western Boundary Current transports: Preliminary results from 26.5�N in the Atlantic. Geophysical Research Letters, 33(17):L17610, doi:10.1029/2006GL026965 (2006).

Transport fluctuations of the deep limb of the Meridional Overturning Circulation (MOC) near the western boundary are presented from a line of inverted echo sounders, bottom pressure sensors, and a deep current meter east of Abaco Island, Bahamas, at 26.5°N from September 2004 through September 2005. The mean southward flow between 800 dbar and 4800 dbar was 39 x 10⁶ m³ s^-1, with a northward recirculation of 28 x 10⁶ m³ s^-1, leaving a net southward flow of 11 x 10⁶ m³ s^-1 as the through-flow of the Deep Western Boundary Current (DWBC). The mean southward DWBC flow essentially equals previous values that were measured at the same location by arrays of current meters deployed from 1986 to 1992. DWBC transport spectra indicate that barotropic and baroclinic changes have very similar energy levels at most periods less than 10 days and that barotropic changes dominate at periods of 10-80 days.

Mestas-Nunez, A.M., and A.J. Miller. Interdecadal variability and climate change in the eastern tropical Pacific: A review. Progress in Oceanography, 69(2-4):267-284 (2006).

In this paper, we review interdecadal climatic variability in the eastern tropical Pacific Ocean. This variability dominates the climatic fluctuations in the North Pacific on scales between ENSO and the centennial trend and is commonly referred to as the Pacific Decadal Oscillation or PDO. We include a historical overview and a summary of observational work that describes the surface, tropospheric and subsurface signatures of this variability. Descriptions of interdecadal variability are incomplete at best, mostly due to limitations in the observational record. We emphasize that the well-known "ENSO-like" sea surface temperature (SST) pattern describing the PDO may not be an accurate representation. In the eastern tropical Pacific, the SST maxima are displaced north and south of the equator with larger amplitudes in the northern branch near the coast of North America, which has significant implications for the troposphere-driven circulations. Several mechanisms have been proposed to explain the PDO. We review these mechanisms and models, which capture our present level of understanding of the problem. We conclude by reporting there is little evidence of both multidecadal variability and the centennial trend in the eastern tropical Pacific. This paper is part of a comprehensive review of the oceanography of the eastern tropical Pacific.

Mestas-Nunez, A.M., A. Bentamy, and K.B. Katsaros. Seasonal and El Ni�o variability in weekly satellite evaporation over the global ocean during 1996-1998. Journal of Climate, 19(10):2025-2035 (2006).

The seasonal and anomaly variability of satellite-derived weekly latent heat fluxes occurring over the global oceans during a three-year period (January 1996-December 1998) is investigated using EOF and harmonic analyses. The seasonal cycle of latent heat flux is estimated by least squares fitting the first three (annual, semiannual, and four month) harmonics to the data. The spatial patterns of amplitudes of these harmonics agree well with the corresponding patterns for wind speed. The annual harmonic captures an oscillation that reflects high evaporation in late fall/early winter and low evaporation in late spring/early summer in both hemispheres, with larger amplitudes in the Northern Hemisphere over the western side of the oceans and significant phase differences within each hemisphere. The main feature of the semiannual harmonic is its large amplitude in the Asian monsoon region (e.g., in the Arabian Sea its amplitude is about 1.5 larger than the annual) and the out-of-phase relationship of this region with the high latitudes of the North Pacific, consistent with other studies. The third harmonic shows three main regions with relatively large amplitudes, one in the Arabian Sea and two out-of-phase regions in the central midlatitude North and South Pacific. After removing this estimate of the seasonal cycle from the data, the leading EOF of the anomalies isolates the 1997-1998 El Ni�o signal, with enhanced evaporation in the eastern tropical Pacific, around the Maritime Continent, in the midlatitude North and South Pacific, and the equatorial Indian Ocean, and reduced evaporation elsewhere around the global ocean during April 1997-April 1998. This pattern is consistent with known patterns of ENSO variability and with the "atmospheric bridge" teleconnection concept. The current study illustrates the usefulness of satellite-derived latent heat fluxes for climatic applications.

Molinari, J., P.P. Dodge, D. Vollaro, K.L. Corbosiero, and F.D. Marks. Mesoscale aspects of the downshear reformation of a tropical cyclone. Journal of the Atmospheric Sciences, 63(1):341-354 (2006).

The downshear reformation of Tropical Storm Gabrielle (2001) was investigated using radar reflectivity and lightning data that were nearly continuous in time, as well as frequent aircraft reconnaissance flights. Initially the storm was a marginal tropical storm in an environment with strong 850-200-hPa vertical wind shear of 12-13 m s^-1 and an approaching upper tropospheric trough. Both the observed outflow and an adiabatic balance model calculation showed that the radial-vertical circulation increased with time as the trough approached. Convection was highly asymmetric, with almost all radar return located in one quadrant left of downshear in the storm. Reconnaissance data show that an intense mesovortex formed downshear of the original center. This vortex was located just south of, rather than within, a strong downshear-left lightning outbreak, consistent with tilting of the horizontal vorticity associated with the vertical wind shear. The downshear mesovortex contained a 972-hPa minimum central pressure, 20 hPa lower than minimum pressure in the original vortex just 3 h earlier. The mesovortex became the new center of the storm, but weakened somewhat prior to landfall. It is argued that dry air carried around the storm from the region of upshear subsidence, as well as the direct effects of the shear, prevented the reformed vortex from continuing to intensify. Despite the subsequent weakening of the reformed center, it reached land with greater intensity than the original center. It is argued that this intensification process was set into motion by the vertical wind shear in the presence of an environment with upward motion forced by the upper tropospheric trough. In addition, the new center formed much closer to the coast and made landfall much earlier than predicted. Such vertical-shear-induced intensity and track fluctuations are important to understand, especially in storms approaching the coast.

Molinari, R.L. NOAA's XBT network, pp. 179-180. In Annual Report on the State of the Ocean and the Ocean Observing System for Climate (FY-2005), J.M. Levy, D.M. Stanitski, and P. Arkin (eds.). NOAA Office of Climate Observation, Silver Spring, MD, 337 pp. (2006).

No abstract.

Molinari, R.L., R. Lumpkin, C. Schmid, and M. McPhaden. NOAA's PIRATA northeast extension, pp. 136-137. In Annual Report on the State of the Ocean and the Ocean Observing System for Climate (FY-2005), J.M. Levy, D.M. Stanitski, and P. Arkin (eds.). NOAA Office of Climate Observation, Silver Spring, MD, 337 pp. (2006).

No abstract.

Montgomery, M.T., M.M. Bell, S.D. Aberson, and M.L. Black. Hurricane Isabel (2003): New insights into the physics of intense storms, Part I: Mean vortex structure and maximum intensity estimates. Bulletin of the American Meteorological Society, 87(10):1335-1347 (2006).

This study is an observational analysis of the inner-core structure, sea surface temperature, outflow layer, and atmospheric boundary layer of an intense tropical cyclone whose intensity and structure is consistent with recent numerical and theoretical predictions of superintense storms. The findings suggest new scientific challenges for the current understanding of hurricanes. Unprecedented observations of the category-5 Hurricane Isabel (2003) were collected during 12-14 September. This two-part article reports novel dynamic and thermodynamic aspects of the inner-core structure of Isabel on 13 September that was made possible by analysis of these data. Here, a composite of the axisymmetric structure of the inner core and environment of Isabel is estimated using global positioning system dropwindsondes and in situ aircraft data. In Part II, an extreme wind speed observation on the same day is discussed in the context of this work. The axisymmetric data composite suggests a reservoir of high-entropy air inside the low-level eye and significant penetration of inflowing near-surface air from outside. The analysis suggests that the low-level air penetrating the eye is enhanced thermodynamically by acquiring additional entropy through interaction with the ocean and replaces air mixed out of the eye. The results support the hypothesis that this high-entropy eye air "turboboosts" the hurricane engine upon its injection into the eyewall clouds. Recent estimates of the ratio of sea-to-air enthalpy and momentum exchange at high wind speeds are used to suggest that Isabel utilized this extra power to exceed the previously assumed intensity upper bound by 10-35 m s^-1 for the given environmental conditions. Additional study with other datasets is encouraged to further test the superintensity hypothesis.

Mooers, C.N.K., H.-S. Kang, I. Bang, and D.P. Snowden. Some lessons learned from comparisons of numerical simulations and observations of the JES circulation. Oceanography, 19(3):86-95 (2006).

No abstract.

Morris, V., P. Clemente-Colon, N.R. Nalli, E. Joseph, R.A. Armstrong, Y. Detres, M.D. Goldberg, P.J. Minnett, and R. Lumpkin. Measuring trans-Atlantic aerosol transport from Africa. EOS, Transactions, American Geophysical Union, 87(50):565, 571 (2006).

An estimated three billion metric tons of mineral aerosols are injected into the troposphere annually from the Saharan desert [Prospero et al., 1996]. Additionally, smoke from biomass burning sites in the savanna grasslands in sub-Saharan Africa contribute significant quantities of smaller-sized aerosols [e.g., Hobbs, 2000]. These windswept aerosols from the African continent are responsible for a variety of climate, health, and environmental impacts on both global and regional scales that span the Western Hemisphere. Unfortunately, in situ measurements of aerosol evolution and transport across the Atlantic are difficult to obtain, and satellite remote sensing of aerosols can be challenging.

Park, G.-H., K. Lee, R.H. Wanninkhof, and R.A. Feely. Empirical temperature-based estimates of variability in the oceanic uptake of CO₂ over the past two decades. Journal of Geophysical Research, 111(C7):C07S07, doi:10.1029/2005JC003090 (2006).

We infer the year-to-year variability of net global air-sea CO₂ fluxes from observed interannual changes in wind speed and estimated differences in CO₂ partial pressure between surface seawater (pCO_2SW) and the overlying atmosphere. Changes in pCO_2SW are estimated from changes in sea surface temperature via seasonal algorithms that relate pCO_2SW to sea surface temperature. Our diagnostic model yields an interannual variability of ±0.18 petagrams (1-sigma, Pg = 10¹⁵ grams) of carbon per year for the period 1982-2001. El Niño Southern Oscillation-induced changes in the equatorial efflux contribute approximately 70% of the diagnostic modeled global variability. Regional flux anomalies for areas outside the equatorial Pacific are found to neither systematically reinforce nor counteract each other during times of transition from El Niño years to normal years. The interannual variability of ±0.18 Pg C yr^-1 obtained in the present work is at the low end of previous estimates that falls in the range of ±0.2 to ±0.5 Pg C yr^-1. Of the previous estimates, lower values are generally estimated from global ocean circulation-biogeochemical models, while higher values are derived from atmospheric inversion models constrained by atmospheric CO₂ observations. Comparisons of our modeled results with two time series data sets and equatorial Pacific data suggest that our diagnostic model is not able to capture the full range of pCO_2SW variations; this is probably due to the inability of the empirical model to fully account for changes in surface pCO_2SW related to ocean biological and physical processes. The small interannual variability in our modeled fluxes suggests that observed year-to-year variations in the rate of atmospheric CO₂ increase are primarily caused by changes in the rate of CO₂ uptake by the land biosphere.

Pelegri, J.L., J.H. Churchill, A.D. Kirwan, S.-K. Lee, R.E. Munn, and N.R. Pettigrew. Gabriel T. Csanady: Understanding the physics of the ocean. Progress in Oceanography, 70(2-4):91-112 (2006).

Gabriel T. Csanady turned 80 in December 2005, and we celebrate it with this special Progress in Oceanography issue. It comprises 20 papers covering some of the many areas that Gabe contributed significantly throughout his professional career. In this introductory paper, we briefly review Gabe's career as an engineer, meteorologist and oceanographer, and highlight some of his major contributions to oceanography, both as a scientist as well as an educator. But we also use this opportunity to remember and thank Gabe, and his wife Joyce, for being such good friends and mentors to several generations of oceanographers. The authors of the collection of papers in this volume deserve special thanks for their efforts. We also are pleased to acknowledge the support of Progress in Oceanography's editor, Detlef Quadfasel, and the many anonymous reviewers who generously contributed their time and expertise.

Piekle, R.A., C.W. Landsea, M. Mayfield, J. Laver, and R. Pasch. Reply to "Hurricanes and global warming potential linkages and consequences." Bulletin of the American Meteorological Society, 87(5):628-631 (2006).

No abstract.

Plattner, S., D.M. Mason, G.A. Leshkevich, D.J. Schwab, and E.S. Rutherford. Classifying and forecasting coastal upwellings in Lake Michigan using satellite-derived temperature images and buoy data. Journal of Great Lakes Research, 32(1):63-76 (2006).

Coastal upwellings are common in the Great Lakes but have lacked enumeration and systematic classification of spatial extent, frequency, duration, and magnitude. Near real-time sea surface temperature (SST) images derived from the Advanced Very High Resolution Radiometer (AVHRR) provide indices of upwelling events, but visual inspection of daily images can be tedious. Moreover, the definition of what constitutes an upwelling from AVHRR data is subjective. We developed a semi-automated method to classify upwellings during the period of thermal stratification using daily, cloud-free surface temperature charts from AVHRR SST data. Then we statistically evaluated the location, frequency, magnitude, extent, and duration of upwelling events in Lake Michigan from 1992-2000. Further, we analyzed meteorological data from the National Data Buoy Center buoys in an attempt to improve the reliability of the classification and to provide a means for future forecast of coastal upwelling. Although variable, upwelling events along the western shoreline were preceded by four days of southerly and west-to-northwesterly winds, while upwelling events occurring along the eastern shore were preceded by four days of northerly winds. Probability of an upwelling event occurring was a function of the direction-weighted wind speed, reaching a 100% probability at direction weighted wind speeds of 11 m s^-1 for the western shore. Probability of an upwelling occurrence along the east coast reached 73% at 11 m s^-1 and 100% at 13 m s^-1. Continuous measurements of wind data with a sufficient temporal resolution are required during the entire upwelling season to improve the predictability of upwellings.

Reynolds, C.A., M.S. Peng, S.J. Majumdar, S.D. Aberson, C.H. Bishop, and R. Buizza. Interpretation of tropical cyclone targeting guidance. Preprints, 27th Conference on Hurricanes and Tropical Meteorology, Monterey, CA, April 24-28, 2006. American Meteorological Society, Boston, 10 pp. (CD-ROM) (2006).

No abstract.

Riishojgaard, L.P., R. Atlas, and G.D. Emmitt. Reply to "The impact of Doppler lidar wind observations on a single-level meteorological analysis." Journal of Applied Meteorology and Climatology, 45(6):887-888 (2006).

No abstract.

Roemmich, D.H., R.E. Davis, S.C. Riser, W.B. Owens, R.L. Molinari, S.L. Garzoli, and G.C. Johnson. The ARGO Project: Global ocean observations for understanding and prediction of climate variability, pp. 187-191. In Annual Report on the State of the Ocean and the Ocean Observing System for Climate (FY-2005), J.M. Levy, D.M. Stanitski, and P. Arkin (eds.). NOAA Office of Climate Observation, Silver Spring, MD, 337 pp. (2006).

No abstract.

Rogers, R.F., M.L. Black, F.D. Marks, K.M. Valde, and S.S. Chen. A comparison of tropical cyclone hydrometeor profiles from TRMM, airborne radar, and high-resolution simulations. Preprints, 27th Conference on Hurricanes and Tropical Meteorology, Monterey, CA, April 24-28, 2006. American Meteorological Society, Boston, 3 pp. (CD-ROM) (2006).

No abstract.

Rogers, R.F., M.L. Black, R. Hood, J. Halverson, E. Zipser, and G. Heymsfield. The Intensity Forecasting Experiment (IFEX): A NOAA multi-year field program for improving tropical cyclone intensity forecasting. Preprints, 27th Conference on Hurricanes and Tropical Meteorology, Monterey, CA, April 24-28, 2006. American Meteorological Society, Boston, 5 pp. (CD-ROM) (2006).

No abstract.

Rogers, R.F., M.L. Black, P.T. Willis, R.A. Black, A. Heymsfield, A. Bansemer, and G. Heymsfield. An evaluation of the microphysics fields of Hurricane Dennis (2005) at different stages of its lifecycle. Preprints, 27th Conference on Hurricanes and Tropical Meteorology, Monterey, CA, April 24-28, 2006. American Meteorological Society, Boston, 4 pp. (CD-ROM) (2006).

No abstract.

Rogers, R.F., S.D. Aberson, M.L. Black, P.G. Black, J.J. Cione, P.P. Dodge, J.P. Dunion, J.F. Gamache, J. Kaplan, M.D. Powell, L.N. Shay, N. Surgi, and E.W. Uhlhorn. The Intensity Forecasting Experiment: A NOAA multi-year field program for improving tropical cyclone intensity forecasts. Bulletin of the American Meteorological Society, 87(11):1523-1537 (2006).

In 2005, NOAA's Hurricane Research Division (HRD), part of the Atlantic Oceanographic and Meteorological Laboratory, began a multi-year experiment called the Intensity Forecasting Experiment (IFEX). By emphasizing a partnership among NOAA's HRD, Environmental Modeling Center (EMC), National Hurricane Center (NHC), Aircraft Operations Center (AOC), and National Environmental Satellite Data Information Service (NESDIS), IFEX represents a new approach for conducting hurricane field program operations. IFEX is intended to improve the prediction of tropical cyclone (TC) intensity change by: (1) collecting observations that span the TC life cycle in a variety of environments; (2) developing and refining measurement technologies that provide improved real-time monitoring of TC intensity, structure, and environment; and (3) improving the understanding of the physical processes important in intensity change for a TC at all stages of its life cycle. This paper presents a summary of the accomplishments of IFEX during the 2005 hurricane season. New and refined technologies for measuring such fields as surface and three-dimensional wind fields, and the use of unmanned aerial vehicles, were achieved in a variety of field experiments that spanned the life cycle of several tropical cyclones, from formation and early organization to peak intensity and subsequent landfall or extratropical transition. Partnerships with other experiments during 2005 also expanded the spatial and temporal coverage of the data collected in 2005. A brief discussion of the plans for IFEX in 2006 is also provided.

Russell, J.L., C. Sweeney, A. Gnanadesikan, R.A. Feely, and R. Wanninkhof. Optimal network design to detect spatial patterns and variability of ocean carbon sources and sinks from underway surface pCO₂ measurements, pp. 229-231. In Annual Report on the State of the Ocean and the Ocean Observing System for Climate (FY-2005), J.M. Levy, D.M. Stanitski, and P. Arkin (eds.). NOAA Office of Climate Observation, Silver Spring, MD, 337 pp. (2006).

No abstract.

Sabine, C.L., R.A. Feely, and R.H. Wanninkhof. Global oceans: Ocean carbon. In State of the Climate in 2005, K.A. Shein, A.M. Waple, H.J. Diamond, and J.M. Levy. Bulletin of the American Meteorological Society, 87(6):S29-S30 (2006).

No abstract.

Sabine, C.L., R.A. Feely, and R. Wanninkhof. The global ocean carbon cycle: Inventories, sources, and sinks, pp. 97-104. In Annual Report on the State of the Ocean and the Ocean Observing System for Climate (FY-2005), J.M. Levy, D.M. Stanitski, and P. Arkin (eds.). NOAA Office of Climate Observation, Silver Spring, MD, 337 pp. (2006).

The ocean plays a major role in the global carbon cycle. Long-term (decadal) changes in ocean carbon inventory are examined by repeating measurements that are made along specific cruise tracks at intervals of 5-15 years. Recent cruises have suggested that the relative role of the Pacific versus the Atlantic storage of CO₂ has changed over the last decade. Shorter-term (daily to inter-annual) changes in ocean carbon uptake are examined with sea-air CO₂ flux estimates from instruments deployed on ships and moorings. The growing surface CO₂ data set also indicates that there is significant interannual variability in the sea-air CO₂ flux.

Schmid, C., and G.J. Goni. Evaluating the ocean observing system: Performance measurement for heat storage, pp. 261-262. In Annual Report on the State of the Ocean and the Ocean Observing System for Climate (FY-2005), J.M. Levy, D.M. Stanitski, and P. Arkin (eds.). NOAA Office of Climate Observation, Silver Spring, MD, 337 pp. (2006).

No abstract.

Serafy, J.E., T.R. Capo, and C.R. Kelble. Live capture of larval billfishes: Design and field testing of the continuous access Neuston observation net (CANON). Bulletin of Marine Science, 79(3):853-857 (2006).

Basic research on larval billfish biology and ecology has been hampered by difficulties with species identification, the capture of live specimens, and their survival after capture (Richards, 1974; Post et al., 1997; Serafy et al., 2003). Whereas, genetic techniques are helping to resolve the identification problems (McDowell and Graves, 2002; Hyde et al., 2005; Luthy et al., 2005), obtaining live, uninjured billfish larvae for scientific study remains a serious obstacle (Idrisi et al., 2003; Serafy et al., 2003). To date, the most successful effort to collect live istiophorid larvae, and to subsequently maintain them in captivity, was conducted by Post et al. (1997). They sampled over a 2-yr period off Miami, Florida with a circular, 1 m diameter plankton net with 1 mm mesh. By limiting their Neuston tow duration to 2 min or less, overall larval istiophorid survival immediately after collection was 30%. Building on the Post et al. (1997) work, we addressed the problem of live billfish collection by developing a new Neuston gear in which tow duration can span, uninterrupted, whatever time period desired, and while underway, its cod-end contents are both viewable and immediately collectable. The rationale behind the "continuous access Neuston observation net" (CANON) design is that the key to minimizing larval injury (due to net abrasion, turbulence, and interactions with other organisms in the cod-end) lies in reducing the time larvae spend in the collection gear. Here, we describe the components, configuration, and operation of the CANON as well as provide results of its performance relative to conventional Neuston net sampling. Possible future applications for this new gear are also described.

Shay, L.K., and E.W. Uhlhorn. Loop Current interactions during Hurricanes Isidore and Lili. Preprints, 27th Conference on Hurricanes and Tropical Meteorology, Monterey, CA, April 24-28, 2006. American Meteorological Society, Boston, 4 pp. (CD-ROM) (2006).

No abstract.

Shen, B.-W., R. Atlas, J.-D. Chern, O. Reale, S.-J. Lin, T. Lee, and J. Chang. The 0.125 degree finite-volume general circulation model on the NASA Columbia supercomputer: Preliminary simulations of mesoscale vortices. Geophysical Research Letters, 33(5):L05801, doi:10.1029/2005GL024594 (2006).

The NASA Columbia supercomputer was ranked second on the TOP500 List in November 2004. Such a quantum jump in computing power provides unprecedented opportunities to conduct ultra-high resolution simulations with the finite-volume General Circulation Model (fvGCM). During 2004, the model was run in real time experimentally at 0.25 degree resolution producing remarkable hurricane forecasts (Atlas et al., 2005). In 2005, the horizontal resolution was further doubled, which makes the fvGCM comparable to the first mesoscale resolving General Circulation Model at the Earth Simulator Center (Ohfuchi et al., 2004). Nine 5-day 0.125 degree simulations of three hurricanes in 2004 are presented first for model validation. Then it is shown how the model can simulate the formation of the Catalina eddies and Hawaiian lee vortices, which are generated by the interaction of the synoptic-scale flow with surface forcing, and have never been reproduced in a GCM before.

Shen, B.-W., R. Atlas, O. Reale, S.-J. Lin, J.-D. Chern, J. Chang, C. Henze, and J.-L. Li. Hurricane forecasts with a global mesoscale-resolving model: Preliminary results with Hurricane Katrina (2005). Geophysical Research Letters, 33(13):L13813, doi:10.1029/2006GL026143 (2006).

It is known that General Circulation Models (GCMs) have insufficient resolution to accurately simulate hurricane near-eye structure and intensity. The increasing capabilities of high-end computers have changed this. The mesoscale-resolving finite-volume GCM (fvGCM) has been experimentally deployed on the NASA Columbia supercomputer, and its performance is evaluated in this study by choosing Hurricane Katrina as an example. In late August 2005, Katrina underwent two stages of rapid intensification, and became the sixth most intense hurricane in the Atlantic. Six 5-day simulations of Katrina at both 0.25° and 0.125° show comparable track forecasts but the 0.125° runs provide much better intensity forecasts, producing the center pressure with errors of only �12 hPa. In the runs examined in this study, the 0.125° simulates better near-eye wind distributions and a more realistic average intensification rate. To contribute to the ongoing research on the effects of disabling convection parameterization (CP), we present promising results by comparing 0.125° runs with disabled CPs against runs with enabled CPs.

Stabenau, E.R., J.C. Hendee, and L. Florit. Techniques for the automated assessment of intense light and high sea temperature on coral response. Proceedings, 10th International Coral Reef Symposium, Okinawa, Japan, June 28-July 2, 2004. International Society for Coral Reef Studies, 702-708 (2006).

Field observations of temperature and the intensity of light were used in concert with data from a continuously monitoring pulse amplitude modulating (PAM) fluorometer to create an expert system decision table of in hospit zooxanthellae response to high sea temperature and intense light. A diffuse attenuation based spectral slope coefficient (SKd) is developed to provide real-time enhancement of optical data from discrete detector bands to estimate the full spectra and intensity of light at a coral's surface. During studies with a PAM fluorometer, seawater temperature was increased by less than 1°C (starting temperature 29.4°C) over four days, and resulted in subtle decreases in fluorescent yield in two Montastrea faveolata ust before the onset of coral bleaching. Following this increase, cloudy conditions reduced insolation levels which lead to fluroescent yield recovery from a low night-time value of 0.56 back to an initial value of 0.61.

Stern, D., and S.D. Aberson. Extreme vertical winds measured by dropsondes in hurricanes. Preprints, 27th Conference on Hurricanes and Tropical Meteorology, Monterey, CA, April 24-28, 2006. American Meteorological Society, Boston, 5 pp. (CD-ROM) (2006).

No abstract.

Sun, W., M. Cetin, W.C. Thacker, T.M. Chin, and A.S. Willsky. Variational approaches on discontinuity localization and field estimation in sea surface temperature and soil moisture. IEEE Transactions on Geoscience and Remote Sensing, 44(2):336-350 (2006).

Some applications in remote sensing require estimating a field containing a discontinuity whose exact location is a priori unknown. Such fields of interest include sea surface temperature in oceanography and soil moisture in hydrology. For the former, oceanic fronts form a temperature discontinuity, while in the latter sharp changes exist across the interface between soil types. To complicate the estimation process, remotely sensed measurements often exhibit regions of missing observations due to occlusions such as cloud cover. Similarly, water surface and ground-based sensors usually provide only an incomplete set of measurements. Traditional methods of interpolation and smoothing for estimating the fields from such potentially sparse measurements often blur across the discontinuities in the field.

Takahashi, T., S.C. Sutherland, R.A. Feely, and R.H. Wanninkhof. Decadal change of the surface water pCO₂ in the North Pacific: A synthesis of 35 years of observations. Journal of Geophysical Research, 111(C7):C07S05, doi:10.1029/2005JC003074 (2006).

Surface water pCO₂ data observed over the three decades between 1970 and 2004 are analyzed for space and time (mean decadal) variability in 32 10° x 10° box areas over the North Pacific Ocean north of 10°N. During this period, the pCO₂ values at SST increased at a mean decadal rate of 12.0 � 4.8 µatm decade^-1 in all but four areas located in the vicinity of the Bering and Okhotsk Seas, where they decreased at a mean rate of -11.1 � 5.7 µatm decade^-1. The mean rate of increase for the open ocean areas is indistinguishable from the mean atmospheric CO₂ increase rate of 15 µatm decade^-1 (or 1.5 ppm yr^-1) suggesting that the North Pacific surface waters as a whole have been following the atmospheric CO₂ increase. However, the rate of increase varies geographically, reflecting differences in local oceanographic processes including lateral mixing of waters from marginal seas, upwelling of subsurface waters and biological activities. The decrease observed in the southern Bering Sea and the peripheries of the Okhotsk Sea may be accounted for by the combined effects of intensified biological production and changes in lateral and vertical mixing in these areas. The natural logarithm of wintertime pCO₂ values normalized to a constant temperature and salinity of 14.3°C and 34.0 (the basin mean values, respectively) is correlated with winter SST. Using this relationship, the wintertime TCO₂ in mixed layer can be expressed as a function of winter SST with a standard error of �5 µmol kg^-1.

Takahashi, T., F. Millero, R. Key, D. Chipman, E. Peltola, S. Rubin, C. Sweeney, and S. Sutherland. Determination of carbon dioxide, hydrographic, and chemical parameters during the R/V Nathaniel B. Palmer cruise in the southern Indian Ocean (WOCE section SO4I, 3 May-4 July 1996). Oak Ridge National Laboratory/Carbon Dioxide Information Analysis Center, ORNL/CDIAC-150, NDP-086, 50 pp. (2006).

This report discusses the procedures and methods used to measure total carbon dioxide (TCO₂), total alkalinity (TALK), and partial pressure of CO₂ (pCO₂) at hydrographic stations during the cruise of research vessel (R/V) Nathaniel B. Palmer in the Southern Indian Ocean on the S04I section as a part of the Joint Global Ocean Flux Study (JGOFS)/World Ocean Circulation Experiment (WOCE). The carbon-related measurements were sponsored by the U.S. Department of Energy (DOE). The expedition started in Cape Town, South Africa, on May 3, 1996, and ended in Hobart, Australia, on July 4, 1996. Instructions for accessing the data are provided. The TCO₂ was measured in discrete water samples using the Lamont-Doherty Earth Observatory (LDEO) coulomteric system with an overall precision of �1.7 µmol/kg. TALK was determined by potentiometric titration with an overall precision of �1.7 µmol/kg. During the S04I cruise pCO₂ was also measured using the LDEO equilibrator-gas chromatograph system with a precision of 0.5% (including the station-to-station reproducibility) at a constant temperature of 4.0°C. The R/V Nathaniel B. Palmer S04I data set is available free of charge as a numeric data package (NDP) from the Carbon Dioxide Information Analysis Center. The NDP consists of the oceanographic data files and this printed documentation, which describes the contents and format of all files as well as the procedures and methods used to obtain the data.

Tory, K.J., M.T. Montgomery, and N.E. Davidson. Prediction and diagnosis of tropical cyclone formation in an NWP system, Part I: The critical role of vortex enhancement in deep convection. Journal of the Atmospheric Sciences, 63(12):3077-3090 (2006).

This is the first of a three-part investigation into tropical cyclone (TC) genesis in the Australian Bureau of Meteorology's Tropical Cyclone Limited Area Prediction System (TC-LAPS), an operational numerical weather prediction (NWP) forecast model. The primary TC-LAPS vortex enhancement mechanism is presented in Part I, the entire genesis process is illustrated in Part II using a single TC-LAPS simulation, and in Part III a number of simulations are presented exploring the sensitivity and variability of genesis forecasts in TC-LAPS. The primary vortex enhancement mechanism in TC-LAPS is found to be convergence/stretching and vertical advection of absolute vorticity in deep intense updrafts, which result in deep vortex cores of 60-100 km in diameter (the minimum resolvable scale is limited by the 0.15� horizontal grid spacing). On the basis of the results presented, it is hypothesized that updrafts of this scale adequately represent mean vertical motions in real TC genesis convective regions, and perhaps that explicitly resolving the individual convective processes may not be necessary for qualitative TC genesis forecasts. Although observations of sufficient spatial and temporal resolution do not currently exist to support or refute this proposition, relatively large-scale (30 km and greater), lower- to midlevel tropospheric convergent regions have been observed in tropical oceanic environments during the Global Atmospheric Research Programme (GARP) Atlantic Tropical Experiment (GATE), the Equatorial Mesoscale Experiment (EMEX), and the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE), and regions of extreme convection of the order of 50 km are often (remotely) observed in TC genesis environments. These vortex cores are fundamental for genesis in TC-LAPS. They interact to form larger cores, and provide net heating that drives the system-scale secondary circulation, which enhances vorticity on the system scale akin to the classical Eliassen problem of a balanced vortex driven by heat sources. These secondary vortex enhancement mechanisms are documented in Part II. In some recent TC genesis theories featured in the literature, vortex enhancement in deep convective regions of mesoscale convective systems (MCSs) has largely been ignored. Instead, they focus on the stratiform regions. While it is recognized that vortex enhancement through midlevel convergence into the stratiform precipitation deck can greatly enhance midtropospheric cyclonic vorticity, it is suggested here that this mechanism only increases the potential for genesis, whereas vortex enhancement through low- to midlevel convergence into deep convective regions is necessary for genesis.

Tory, K.J., M.T. Montgomery, N.E. Davidson, and J.D. Kepert. Prediction and diagnosis of tropical cyclone formation in an NWP system, Part II: A diagnosis of Tropical Cyclone Chris formation. Journal of the Atmospheric Sciences, 63(12):3091-3113 (2006).

This is the second of a three-part investigation into tropical cyclone (TC) genesis in the Australian Bureau of Meteorology's Tropical Cyclone Limited Area Prediction System (TC-LAPS). The primary TC-LAPS vortex enhancement mechanism (convergence/stretching and vertical advection of absolute vorticity in convective updraft regions) was presented in Part I. In this paper (Part II) results from a numerical simulation of TC Chris (western Australia, February 2002) are used to illustrate the primary and two secondary vortex enhancement mechanisms that led to TC genesis. In Part III a number of simulations are presented exploring the sensitivity and variability of genesis forecasts in TC-LAPS. During the first 18 h of the simulation, a mature vortex of TC intensity developed in a monsoon low from a relatively benign initial state. Deep upright vortex cores developed from convergence/stretching and vertical advection of absolute vorticity within the updrafts of intense bursts of cumulus convection. Individual convective bursts lasted for 6-12 h, with a new burst developing as the previous one weakened. The modeled bursts appear as single updrafts, and represent the mean vertical motion in convective regions because the 0.15� grid spacing imposes a minimum updraft scale of about 60 km. This relatively large scale may be unrealistic in the earlier genesis period when multiple smaller-scale, shorter-lived convective regions are often observed, but observational evidence suggests that such scales can be expected later in the process. The large scale may limit the convection to only one or two active bursts at a time, and may have contributed to a more rapid model intensification than that observed. The monsoon low was tilted to the northwest, with convection initiating about 100-200 km west of the low-level center. The convective bursts and associated upright potential vorticity (PV) anomalies were advected cyclonically around the low, weakening as they passed to the north of the circulation center, leaving remnant cyclonic PV anomalies. Strong convergence into the updrafts led to rapid ingestion of nearby cyclonic PV anomalies, including remnant PV cores from decaying convective bursts. Thus convective intensity, rather than the initial vortex size and intensity, determined dominance in vortex interactions. This scavenging of PV by the active convective region, termed diabatic upscale vortex cascade, ensured that PV cores grew successively and contributed to the construction of an upright central monolithic PV core. The system-scale intensification (SSI) process active on the broader scale (300-500-km radius) also contributed. Latent heating slightly dominated adiabatic cooling within the bursts, which enhanced the system-scale secondary circulation. Convergence of low- to midlevel tropospheric absolute vorticity by this enhanced circulation intensified the system-scale vortex. The diabatic upscale vortex cascade and SSI are secondary processes dependent on the locally enhanced vorticity and heat respectively, generated by the primary mechanism.

Tracey, K.L., D.R. Watts, C.S. Meinen, and D.S. Luther. Synoptic maps of temperature and velocity within the Subantarctic Front south of Australia. Journal of Geophysical Research, 111(C10):C10016, doi:1029/2005JC002905 (2006).

From April 1995 to March 1997 a 450-km array of inverted echo sounders, horizontal electric field recorders, and current meters measured the horizontal and vertical structure of the current, temperature, and salinity fields associated with the Subantarctic Front (SAF) south of Australia. Synoptic maps of the temperature and velocity fields often show the SAF divided into two zonally separated jets, which are also found in the mean. These jets were in close proximity yet directed toward different azimuths. The daily maps also show that the SAF often flowed as a single strong jet, during which times it underwent vigorous meandering, with crest-to-trough meridional distances ~250 km. These meanders stalled within the array and contorted to form "S"-shaped paths. In one case a cold-core ring was formed. Propagating meanders have periods of 20-70 days, wavelengths of 240-420 km, and phase speeds of 12-6 km d^-1. Deep currents reveal strong cyclones and anticyclones propagating primarily eastward through the array beneath the meandering jet. Thus, at times the deep flow is aligned with the upper flow, whereas at other times, significant barotropic flows cross the upper front. Occasionally, the northern Polar Front was also found within the array. The observed variability illustrates how the interaction of a meandering current with transient features such as meanders and eddies makes the identification of a front difficult when a single isotherm or isopycnal is utilized as the definition.

Uhlhorn, E.W., and L.K. Shay. Mechanical energy and vorticity balances within the ocean mixed layer under tropical cyclones. Preprints, 27th Conference on Hurricanes and Tropical Meteorology, Monterey, CA, April 24-28, 2006. American Meteorological Society, Boston, 3 pp. (CD-ROM) (2006).

No abstract.

Walsh, K.J.E., M. Fiorina, C.W. Landsea, and K. McInnes. Objective detection of tropical cyclones in climate models. Preprints, 27th Conference on Hurricanes and Tropical Meteorology, Monterey, CA, April 24-28, 2006. American Meteorological Society, Boston, 2 pp. (CD-ROM) (2006).

No abstract.

Wang, C. An overlooked feature of tropical climate: Inter-Pacific Atlantic variability. Geophysical Research Letters, 33(12):LI2702, doi:10.1029/2006GL026324 (2006).

Both the tropical Pacific and Atlantic host an equatorial mode of interannual variability called the Pacific El Ni�o and the Atlantic Ni�o, respectively. Although the Pacific El Ni�o does not correlate with the Atlantic Ni�o, anomalous warming or cooling of the two equatorial oceans can form an inter-Pacific-Atlantic sea surface temperature (SST) gradient variability that induces surface zonal wind anomalies over equatorial South America and over some regions of both ocean basins. The zonal wind anomalies act to bridge the interaction of the two ocean basins, reinforcing the inter-Pacific-Atlantic SST gradient through atmospheric Walker circulations and oceanic dynamics. Thus, a positive feedback seems to exist for climate variability of the tropical Pacific-Atlantic Oceans and atmosphere system, in which the inter-basin SST gradient is coupled to the overlying atmospheric wind. Rainfall responds to the inter-Pacific-Atlantic SST gradient by showing an anti-symmetric configuration between the two equatorial oceans, suggesting that rainfall is sensitive to the equatorial inter-basin SST gradient, regardless of which ocean is anomalously warm or cold.

Wang, C., and P.C. Fiedler. ENSO variability in the eastern tropical Pacific: A review. Progress in Oceanography, 69(2-4):239-266 (2006).

El Ni�o-Southern Oscillation (ENSO) encompasses variability in both the eastern and western tropical Pacific. During the warm phase of ENSO, the eastern tropical Pacific is characterized by equatorial positive sea surface temperature (SST) and negative sea level pressure (SLP) anomalies, while the western tropical Pacific is marked by off-equatorial negative SST and positive SLP anomalies. Corresponding to this distribution are equatorial westerly wind anomalies in the central Pacific and equatorial easterly wind anomalies in the far western Pacific. Occurrence of ENSO has been explained as either a self-sustained, naturally oscillatory mode of the coupled ocean-atmosphere system or a stable mode triggered by stochastic forcing. Whatever the case, ENSO involves the positive ocean-atmosphere feedback hypothesized by Bjerknes. After an El Ni�o reaches its mature phase, negative feedbacks are required to terminate growth of the mature El Ni�o anomalies in the central and eastern Pacific. Four requisite negative feedbacks have been proposed: reflected Kelvin wave at the ocean western boundary, discharge process due to Sverdrup transport, western Pacific wind-forced Kelvin wave, and anomalous zonal advection. These negative feedbacks may work together for terminating El Ni�o, with their relative importance being time-dependent. ENSO variability is most pronounced along the equator and the coast of Ecuador and Peru. However, the eastern tropical Pacific also includes a warm pool north of the equator where important variability occurs. Seasonally, ocean advection seems to play an important role for SST variations of the eastern Pacific warm pool. Interannual variability in the eastern Pacific warm pool may be largely due to a direct oceanic connection with the ENSO variability at the equator. Variations in temperature, stratification, insolation, and productivity associated with ENSO have implications for phytoplankton productivity and for fish, birds, and other organisms in the region. Long-term changes in ENSO variability may be occurring and are briefly discussed. This paper is part of a comprehensive review of the oceanography of the eastern tropical Pacific.

Wang, W., and C. Wang. Formation and decay of the spring warm pool in the South China Sea. Geophysical Research Letters, 33(2):L02615, doi:10.1029/2005GL025097 (2006).

As part of the southeast Asian monsoon system, the South China Sea (SCS) is characterized by monsoon wind transition from northeasterly to southwesterly in the boreal spring. Correspondingly, a spring warm pool (SWP) with mixed layer temperature warmer than 29°C is formed and peaked in May over the central SCS and then decays in June. Calculations of the heat budget showed that the surface heat flux and ocean dynamics have different roles in the formation and decay of the SWP. The surface heat flux is found to play a dominant role for the formation of the SWP in May. The onset of the southwest monsoon corresponds to an increase in cloudiness and rainfall and a strong wind speed in the SCS that decrease the surface heat flux in June. Moreover, the onset of the southwest monsoon also changes oceanic circulation pattern that advects cold water from the northwest to the southeast and pumps cold water into the upper mixed layer. These cooling effects overcome the warming effect of the surface heat flux, resulting in the decay of the SWP in June.

Wang, C., D.B. Enfield, S.-K. Lee, and C.W. Landsea. Influences of the Atlantic warm pool on western hemisphere summer rainfall and Atlantic hurricanes. Journal of Climate, 19(12):3011-3028 (2006).

The Atlantic warm pool (AWP) of water warmer than 28.5°C comprises the Gulf of Mexico, the Caribbean Sea, and the western tropical North Atlantic (TNA). The AWP reaches its maximum size around September, with large AWPs being almost three times larger than small ones. Although ENSO teleconnections are influential on the AWP, about two-thirds of the large and small AWP variability appears unrelated to ENSO. The AWP is usually geographically different from the TNA; however, the AWP size is correlated with the TNA SST anomalies. During August to October, large AWPs and warm TNA are associated with increased rainfall over the Caribbean, Mexico, the eastern subtropical Atlantic, and the southeast Pacific, and decreased rainfall in the northwest United States, Great Plains, and eastern South America. In particular, rainfall in the Caribbean, Central America, and eastern South America from August to October is mainly related to the size of the AWP. Large (small) AWPs and warm (cold) TNA correspond to a weakening (strengthening) of the northward surface winds from the AWP to the Great Plains that disfavors (favors) moisture transport for rainfall over the Great Plains. On the other hand, large (small) AWPs and warm (cold) TNA strengthen (weaken) the summer regional Atlantic Hadley circulation that emanates from the warm pool region into the southeast Pacific, changing the subsidence over the southeast Pacific and thus the stratus cloud and drizzle there. The large AWP, associated with a decrease in sea level pressure and an increase in atmospheric convection and cloudiness, corresponds to a weak tropospheric vertical wind shear and a deep warm upper ocean, and thus increases Atlantic hurricane activity.

Wang, C., W. Wang, D. Wang, and Q. Wang. Interannual variability of the South China Sea associated with El Ni�o. Journal of Geophysical Research, 111(C3):C03023, doi:10.1029/2005JC003333 (2006).

Interannual sea surface temperature (SST) anomalies in the South China Sea (SCS) are largely influenced by El Ni�o through El Ni�o-driven atmospheric and oceanic changes. This paper discovers a new observed feature of the SCS SST anomalies: a double-peak evolution following an El Ni�o event. The first and second peaks occur around February and August, respectively, in the subsequent year of the El Ni�o year (denoted by February [+1] and August [+1]). During and after the mature phase of El Ni�o, a change of atmospheric circulation alters the local SCS near-surface air temperature, humidity, cloudiness, and monsoon wind. These factors influence surface heat fluxes and oceanic flows over the SCS that can either warm or cool the SCS depending upon stages of SST anomaly evolution. The shortwave radiation and latent heat flux anomalies are major contributions to the first peak of the SCS SST anomalies, although the geostrophic heat advections warm the western boundary region of the SCS. After the first peak of February [+1], both the Ekman and geostrophic heat advections, assisted with a reduction of the net heat flux anomalies, cool the SCS SST anomalies. In August [+1], the mean meridional geostrophic heat advection makes the SCS SST anomalies peak again. Then, the latent heat flux anomalies (mainly attributed to anomalous air-sea difference in specific humidity) and the mean zonal geostrophic heat advection take over for the cooling of the SCS after the second peak.

Wanninkhof, R., R.A. Feely, N.R. Bates, F.J. Millero, T. Takahashi, and S. Cook. Document ocean carbon sources and sinks: Surface water pCO₂ measurements from ships, pp. 207-215. In Annual Report on the State of the Ocean and the Ocean Observing System for Climate (FY-2005), J.M. Levy, D.M. Stanitski, and P. Arkin (eds.). NOAA Office of Climate Observation, Silver Spring, MD, 337 pp. (2006).

No abstract.

Willoughby, H.E., R.W. Darling, and M.E. Rahn. Parametric representation of the primary hurricane vortex, Part II: A new family of sectionally continuous profiles. Monthly Weather Review, 134(4):1102-1120 (2006).

For applications such as windstorm underwriting or storm-surge forecasting, hurricane wind profiles are often approximated by continuous functions that are zero at the vortex center, increase to a maximum in the eyewall, and then decrease asymptotically to zero far from the center. Comparisons between the most commonly used functions and aircraft observations reveal systematic errors. Although winds near the peak are too strong, they decrease too rapidly with distance away from the peak. Pressure-wind relations for these profiles typically overestimate maximum winds. A promising alternative is a family of sectionally continuous profiles in which the wind increases as a power of radius inside the eye and decays exponentially outside the eye after a smooth polynomial transition across the eyewall. Based upon a sample of 493 observed profiles, the mean exponent for the power law is 0.79 and the mean decay length is 243 km. The database actually contains 606 aircraft sorties, but 113 of these failed quality-control screening. Hurricanes stronger than Saffir-Simpson category 2 often require two exponentials to match the observed rapid decrease of wind with radius just outside the eye and slower decrease farther away. Experimentation showed that a fixed value of 25 km was satisfactory for the faster decay length. The mean value of the slower decay length was 295 km. The mean contribution of the faster exponential to the outer profile was 0.10, but for the most intense hurricanes it sometimes exceeded 0.5. The power-law exponent and proportion of the faster decay length increased with maximum wind speed and decreased with latitude, whereas the slower decay length decreased with intensity and increased with latitude, consistent with the qualitative observation that more intense hurricanes in lower latitudes usually have more sharply peaked wind profiles.

Yablonsky, R.M., I.Ginis, E.W. Uhlhorn, and A. Falkovich. Using AXBTs to improve the performance of coupled hurricane-ocean models. Preprints, 27th Conference on Hurricanes and Tropical Meteorology, Monterey, CA, April 24-28, 2006. American Meteorological Society, Boston, 7 pp. (CD-ROM) (2006).

No abstract.

Zhang, J.-Z. Enhanced sensitivity in flow injection analysis using a long pathlength liquid waveguide capillary flow cell for spectrophotometric detection. Analytical Sciences, 22(1):57-60 (2006).

Incorporation of a liquid waveguide capillary flow cell into a flow injection instrument enhances the sensitivity of flow injection analysis with spectrophotometric detection by two orders of magnitude. Nitrite determination at nM levels has been used to demonstrate the feasibility of this novel technique for trace analysis. Combining the long pathlength spectrophotometry with flow injection analysis, this technique has advantages of low detection limit, good precision and high sample throughput.

Zhang, J.-Z., and C.J. Fischer. A simplified resorcinol method for direct spectrophotometric determination of nitrate in seawater. Marine Chemistry, 99(1-4):220-226 (2006).

A direct, spectrophotometric method has been adapted for quantitative determination of nitrate concentrations in seawater. The method is based on nitration of resorcinol in acidified seawater, resulting in a color product. The absorption spectrum obtained for the reaction product shows a maximum absorption at 505 nm, with a molar absorptivity of 1.7 x 10⁴ L mol^-1 cm^-1. This method has a detection limit of 0.5 µM and is linear up to 400 µM for nitrate. The advantage of this method is that all reagents are in aqueous solutions without involving cadmium granules as a heterogeneous reactant, as in conventional methods, and therefore is simple to implement. Application of the resorcinol to seawater analysis demonstrated that the results obtained are in good agreement with the conventional approach involving the reduction of nitrate by cadmium followed by diazotization. **2005**

Ansorge, I., S. Speich, J. Lutjeharms, G.J. Goni, G. Rautenbach, P. Froneman, and S.L. Garzoli. Monitoring the oceanic flow between Africa and Antarctica: Report of the first Good Hope cruise. South Africa Journal of Science, 101(3-4):29-35 (2005).

No abstract.

Arnold, W.S., G.L. Hitchcock, M.E. Frischer, R. Wanninkhof, and Y.P. Sheng. Dispersal of an introduced larval cohort in a coastal lagoon. Limnology and Oceanography, 50(2):587-597 (2005).

Patterns of larval dispersal influence the structure of marine biological communities, but many aspects of larval dispersal remain poorly understood. For example, much of our present understanding of larval dispersal is based on models that integrate aspects of physical oceanography and larval biology, but the predictions of those models are generally not tested because we lack the methodology for real-time larval tracking. In the present study, we used both modeled and measured data to track an introduced larval cohort essentially from fertilization to presumed settlement. Larvae of the hard clam Mercenaria were released into a labeled water parcel in the Banana River Lagoon, Florida, within 8.5 hours of nursery production and then were tracked for the duration of their estimated 8-day pelagic life span. Comparisons of modeled versus measured larval distribution indicate that the fate of the larvae as predicted by a tracer model and by the concentration of coincidentally released sulfur hexafluoride (SF₆) did not agree with the fate of the larvae as predicted by the path of subsurface drifters and by a particle trajectory model. Thus, modeled predictions of larval dispersal must be interpreted with care. Additionally, one component of larval dispersal that was observed in the study but that was not accounted for in the model was the spread of larvae along the path of advection. That trail of larvae may have important consequences for patterns of recruitment and resultant community structure, but it is not considered in most treatments of larval dispersal.

Atlas, R. Results of recent OSSEs to evaluate the potential impact of lidar winds. In Lidar Remote Sensing for Environmental Monitoring VI, U.N. Singh (ed.). Proceedings, SPIE, 5887:118-125 (2005).

Atlas, R. The impact of AIRS on weather prediction. In Algorithms and Technologies for Multispectral, Hyperspectral, and Ultraspectral Imagery XI, S.S. Shen and P.E. Lewis (eds.). Proceedings, SPIE, 5806:599-606 (2005).

Observing system simulation experiments (OSSE) conducted prior to the launch of AIRS indicated significant potential for AIRS temperature soundings to improve numerical weather prediction (NWP), provided that cloud effects could be cleared effectively. Since the launch of AIRS aboard the AQUA satellite, a detailed geophysical validation of AIRS data has been performed. This included collocations of AIRS temperatures with in situ observations and model analyses, and observing system experiments (OSEs) to evaluate the actual impact of AIRS data on NWP. At the NASA Goddard Space Flight Center, we are evaluating AIRS data in several different forms, and are performing impact studies using multiple data assimilation systems. In general, the results of the OSE confirm the results of the earlier simulation experiments in that a meaningful positive impact of AIRS data is obtained and this impact depends strongly upon the assimilation of partially cloudy AIRS data.

Atlas, R. The impact of current and future polar-orbiting satellite data on numerical weather prediction at NASA/GSFC. In Applications with Weather Satellites, W.P. Menzel and T. Iwasaki (eds.). Proceedings, SPIE, 5658:132-143 (2005).

Satellite observations are a critical component of the global atmospheric observing system and contribute substantially to the current accuracy of numerical weather forecasts. In this paper, two types of experiments related to the effectiveness of these and other observations are described. These are: Observing System Experiments (OSEs), which are conducted to evaluate the impact of an existing observing system; and Observing System Simulation Experiments (OSSEs) which are conducted to evaluate the potential for future observing systems to improve NWP, as well as to evaluate trade-offs in observing system design, and to develop and test improved methods for data assimilation. This paper summarizes the methodology for such experiments and presents selected results from OSEs to evaluate satellite data sets that have recently become available to the global observing system, such as AIRS and SeaWinds, and results from recent OSSEs to determine the potential impact of space-based lidar winds.

Atlas, R., A.Y. Hou, and R. Oreste. Application of SeaWinds scatterometer and TMI-SSM/I rain rates to hurricane analysis and forecasting. Journal of Photogrammetry and Remote Sensing, 59(4):233-243 (2005).

Results provided by two different assimilation methodologies involving data from passive and active space-borne microwave instruments are presented. The impact of the precipitation estimates produced by the TRMM Microwave Imager (TMI) and Special Sensor Microwave/Imager (SSM/I) in a previously developed 1D variational continuous assimilation algorithm for assimilating tropical rainfall is shown on two hurricane cases. Results on the impact of the SeaWinds scatterometer on the intensity and track forecast of a mid-Atlantic hurricane are also presented. This work is the outcome of a collaborative effort between NASA and NOAA and indicates the substantial improvement in tropical cyclone forecasting that can result from the assimilation of space-based data in global atmospheric models.

Atlas, R., O. Reale, B.-W. Shen, S.-J. Lin, J.-D. Chern, W. Putman, T. Lee, K.-S. Yeh, M. Bosilovich, and J. Radakovich. Hurricane forecasting with the high-resolution NASA finite volume general circulation model. Geophysical Research Letters, 32(3):L03807, doi:10.1029/2004GL021513 (2005).

A high-resolution finite volume general circulation model (fvGCM), resulting from a development effort of more than ten years, is now being run operationally at the NASA Goddard Space Flight Center and Ames Research Center. The model is based on a finite volume dynamical core with terrain-following Lagrangian control volume discretization and performs efficiently on massive parallel architectures. The computational efficiency allows simulations at a resolution of a quarter of a degree, which is double the resolution currently adopted by most global models in operational weather centers. Such fine global resolution brings us closer to overcoming a fundamental barrier in global atmospheric modeling for both weather and climate, because tropical cyclones can be more realistically represented. In this work, preliminary results are shown. Fifteen simulations of four Atlantic tropical cyclones in 2002 and 2004, chosen because of varied difficulties presented to numerical weather forecasting, are performed. The fvGCM produces very good forecasts of these tropical systems, adequately resolving problems like erratic track, abrupt recurvature, intense extratropical transition, multiple landfall and reintensification, and interaction among vortices.

Baringer, M.O., and S.L. Garzoli. Western boundary time series in the Atlantic Ocean, pp. 90-101. In Annual Report on the State of the Ocean and Ocean Observing System for Climate (FY-2004), D.M. Stanitski (ed.). NOAA Office of Climate Observation, Silver Spring, MD, 422 pp. (2005).

No abstract.

Baringer, M.O., G.J. Goni, and S.L. Garzoli. Atlantic high density XBT lines, pp. 84-89. In Annual Report on the State of the Ocean and Ocean Observing System for Climate (FY-2004), D.M. Stanitski (ed.). NOAA Office of Climate Observation, Silver Spring, MD, 422 pp. (2005).

No abstract.

Bateman, M., D. Mach, S. Lewis, J. Dye, E. Defer, C.A. Grainger, and P.T. Willis. Comparison of in-situ electric field and radar derived parameters for stratiform clouds in central Florida. Preprints, Conference on Meteorological Applications of Lightning Data, San Diego, CA, January 9-13, 2005. American Meteorological Society, Boston, 8 pp. (2005).

No abstract.

Bell, G.D., S.B. Goldenberg, C.W. Landsea, E.S. Blake, R. Pasch, M. Chelliah, and K. Mo. Atlantic hurricane season. Bulletin of the American Meteorological Society, 86(6):S26-S29 (2005).

No abstract.

Blake, E.S., E.N. Rappaport, J.D. Jarrell, and C.W. Landsea. The deadliest, costliest, and most intense United States tropical cyclones from 1851 to 2004 (and other frequently requested hurricane facts). NOAA Technical Memorandum, NWS TPC-4, 48 pp. (2005).

This technical memorandum lists the deadliest and costliest tropical cyclones in the United States during 1851-2004. The compilation ranks damage, as expressed by monetary losses, in three ways: (1) contemporary estimates; (2) contemporary estimates adjusted by inflation to 2004 dollars; and (3) contemporary estimates adjusted for inflation and the growth of population and personal wealth (Pielke and Landsea, 1998) to 2004. In addition, the most intense (i.e., major) hurricanes to make landfall in the United States during the period are listed. Some additional statistics on United States hurricanes of this and previous centuries, and tropical cyclones in general, are also presented.

Browder, J.A., R. Alleman, S. Markeley, P.B. Ortner, and P.A. Pitts. Biscayne Bay conceptional ecological model. Wetlands, 25(4):854-869 (2005).

Biscayne Bay is a naturally clear-water bay that spans the length of Miami-Dade County, Florida, USA. It is bordered on the east by barrier islands that include Miami Beach and is an almost completely urban bay in the north and a relatively natural bay in the south. Planned water management changes in the next few years may decrease freshwater flows to the bay from present sources, while offering reclaimed wastewater in return. In addition, a project is planned to restore the former diffuse freshwater flow to the Bay through many small creeks crossing coastal wetlands by redistributing the water that now flows into the Bay through several large canals. To guide a science-based, adaptive-management approach to water-management planning, a conceptual ecological model of Biscayne Bay was developed based upon a series of open workshops involving researchers familiar with Biscayne Bay. The CEM model relates ecological attributes of the Bay to outside forcing functions, identified as water management, watershed development, and sea-level rise. The model depicts the effects of these forcing functions on the ecological attributes of the Bay through four stressors. The hypothesized pathways of these effects include salinity patterns, water quality, sediment contaminant concentrations, and physical impacts. Major research questions were identified with regard to uncertainties explicit in the model. The issues addressed include, for example: (1) the quantitative relationship between upstream water management, rainfall, and flow into Biscayne Bay; (2) the salinity gradient required to restore the historical estuarine fish community; (3) the potential effect of freshwater inputs on benthic habitats; and (4) the effect of introduced nutrient and contaminant loads, including the effects of reclaimed wastewater.

Carsey, T.P., and H.E. Willoughby. Ozone measurements from eyewall transects of two Atlantic tropical cyclones. Monthly Weather Review, 133(1):166-174 (2005).

Measurements of ozone (O₃) concentrations obtained during aircraft eyewall crossings of tropical cyclone Floyd (September 1999) and Georges (September 1998) by NOAA P-3 hurricane research aircraft showed marked changes between the intensifying and weakening stages of the storms' life cycles. Renewed deepening appeared to be underway near landfall of both storms. During intensification, ozone levels indicated that air either descended from an altitude <1 km above flight level or was strongly diluted with low-O₃ eyewall air. During weakening, ozone concentrations were low throughout the eye and eyewall, consistent with the eye's being filled with boundary layer air.

Carsey, T.P., R. Ferry, K.D. Goodwin, P.B. Ortner, J.R. Proni, P. Swart, and J.-Z. Zhang. Brevard County nearshore ocean nutrification analysis. NOAA Technical Report, OAR AOML-37 (PB2006-101563), 84 pp. (2005).

In response to public concerns regarding the possibility of elevated nutrients in the Brevard County surf zone, Brevard County and Canaveral Port Authority officials contracted the National Oceanic and Atmospheric Administration (NOAA), Atlantic Oceanographic and Meteorological Laboratory (AOML) in Miami to assemble an expert panel of scientists to critically assess the issue. The panel included scientists from AOML, the Environmental Protection Agency, and the University of Miami's Rosenstiel School for Marine and Atmospheric Science. The expert panel was charged with reviewing scientific data and literature to answer a series of questions aimed at determining the existence of elevated nutrients along Brevard County Beaches and the various impacts of elevated nutrients to near shore ecology and human health. The panel was also tasked with evaluating methods for detecting nutrient sources and the impact of cruise and gaming vessels. Lastly, the panel was asked to make recommendations for future monitoring and research. The panel found that existing data did not support the claim that nutrient levels in the surf zone along Brevard County beaches were elevated. In fact, available data indicated that the Brevard County coast had comparatively less nutrients than other observed regions on Florida's east coast. The nutrient concentrations found in the surf zone should not pose a direct risk to human health. Furthermore, there was no evidence of elevated levels of sewage-indicating bacteria in numerous samples taken within the Brevard County surf zone. There was also no scientific evidence that red tide blooms, caused by the organism Karenia brevis, were related to near shore coastal nutrients off Brevard County beaches. Even if elevated nutrients had been found, the response of near shore ecology would depend on a complex set of factors, such as naturally-occurring biological, physical, meteorological, and geochemical forces, which would need to be considered in an integrated fashion. The panel concluded that although the nitrogen isotope method may be used to help identify sources of pollution, such measurements could not be used in isolation to determine the presence of sewage pollution. Based on information from numerous peer-reviewed sources, the panel concluded that one cannot simply assign a particular value to unambiguously indicate sewage contamination. To effectively utilize this method in Brevard County, a much greater understanding of the nitrogen cycle in this particular ecosystem would be needed, including analysis of isotopes in a variety of local sources and organisms. Additional data would be needed to verify the analysis of nutrient data conducted by the panel and to establish a baseline for any future monitoring efforts. Scientifically rigorous answers to the difficult questions posed to the panel would require a comprehensive interdisciplinary program that would include nutrient and microbiological water quality monitoring, techniques to determine nutrient sources (e.g., stable isotope studies of multiple elements, biochemical sewage markers, and deliberate tracers), circulation studies, and mass-balance and numeric modeling. The scope and expense of such a program implies it would be feasible only with the leveraging that can be obtained by close cooperation and coordination with ongoing and planned federal and state programs.

Cook, S.K., and R.L. Molinari. ENSO observing system, XBT component, task-1 operations, pp. 108-110. In Annual Report on the State of the Ocean and Ocean Observing System for Climate (FY-2004), D.M. Stanitski (ed.). NOAA Office of Climate Observation, Silver Spring, MD, 422 pp. (2005).

No abstract.

Corbosiero, K.L., J. Molinari, and M.L. Black. The structure and evolution of Hurricane Elena (1985), Part 1: Symmetric intensification. Monthly Weather Review, 133(10):2905-2921 (2005).

One of the most complete aircraft reconnaissance and ground-based radar datasets of a single tropical cyclone was recorded in Hurricane Elena (1985) as it made a slow, three-day anticyclonic loop in the Gulf of Mexico. Eighty-eight radial legs and 47 vertical incidence scans were collected aboard NOAA WP-3D aircraft, and 1,142 ground-based radar scans were made of Elena's eyewall and inner rainbands as the storm intensified from a disorganized category 2 to an intense category 3 hurricane. This large amount of continuously collected data made it possible to examine changes that occurred in Elena's inner-core symmetric structure as the storm intensified. On the first day of study, Elena was under the influence of vertical wind shear from an upper-tropospheric trough to the west. The storm was disorganized, with no discernable eyewall and nearly steady values of tangential wind and relative vorticity. Early on the second day of study, a near superposition and constructive interference occurred between the trough and Elena, coincident with upward vertical velocities and the radial gradient of reflectivity becoming concentrated around the 30-km radius. Once an inner wind maximum and eyewall developed, the radius of maximum winds contracted and a sharp localized vorticity maximum emerged, with much lower values on either side. This potentially unstable vorticity profile was accompanied by a maximum in equivalent potential temperature in the eyewall, deeper and stronger inflow out to 24 km from the eyewall, and mean outflow toward the eyewall from the eye. Within 6-12 h, intensification came to an end and Elena began to slowly weaken. Vorticity and equivalent potential temperature at 850 hPa showed indications of prior mixing between the eye and eyewall. During the weakening stage, an outflow jet developed at the eyewall radius. A strong 850-hPa updraft accompanied the outflow jet, yet convection was less active aloft than before. This feature appeared to represent a shallow, outward-sloping updraft channel associated with the spindown of the storm.

DeMaria, M., M. Mainelli, L.K. Shay, J. Knaff, and J. Kaplan. Further improvements to the Statistical Hurricane Intensity Prediction Scheme (SHIPS). Weather and Forecasting, 20(4):531-543 (2005).

Modifications to the Atlantic and east Pacific versions of the operational Statistical Hurricane Intensity Prediction Scheme (SHIPS) for each year from 1997 to 2003 are described. Major changes include the addition of a method to account for the storm decay over land in 2000, the extension of the forecasts from three to five days in 2001, and the use of an operational global model for the evaluation of the atmospheric predictors instead of a simple dry-adiabatic model beginning in 2001. A verification of the SHIPS operational intensity forecasts is presented. Results show that the 1997-2003 SHIPS forecasts had statistically significant skill (relative to climatology and persistence) out to 72 h in the Atlantic, and at 48 and 72 h in the east Pacific. The inclusion of the land effects reduced the intensity errors by up to 15% in the Atlantic, and up to 3% in the east Pacific, primarily for the shorter-range forecasts. The inclusion of land effects did not significantly degrade the forecasts at any time period. Results also showed that the four to five-day forecasts that began in 2001 did not have skill in the Atlantic, but had some skill in the east Pacific. An experimental version of SHIPS that included satellite observations was tested during the 2002 and 2003 seasons. New predictors included brightness temperature information from Geostationary Operational Environmental Satellite (GOES) channel 4 (10.7 µm) imagery, and oceanic heat content (OHC) estimates inferred from satellite altimetry observations. The OHC estimates were only available for the Atlantic basin. The GOES data significantly improved the east Pacific forecasts by up to 7% at 12-72 h. The combination of GOES and satellite altimetry improved the Atlantic forecasts by up to 3.5% through 72 h for those storms west of 50°W.

Eastin, M.D., W.M. Gray, and P.G. Black. Buoyancy of convective vertical motions in the inner core of intense hurricanes, Part I: General statistics. Monthly Weather Review, 133(1):188-208 (2005).

The buoyancy of hurricane convective vertical motions is studied using aircraft data from 175 radial legs collected in 14 intense hurricanes at four altitudes ranging from 1.5 to 5.5 km. The data of each leg are initially filtered to separate convective-scale features from background mesoscale structure. Convective vertical motion events, called cores, are identified using the criteria that the convective-scale vertical velocity must exceed 1.0 m s^-1 for at least 0.5 km. A total of 620 updraft cores and 570 downdraft cores are included in the dataset. Total buoyancy is calculated from convective-scale virtual potential temperature, pressure, and liquid water content using the mesoscale structure as the reference state. Core properties are summarized for the eyewall and rainband regions at each altitude. Characteristics of core average convective vertical velocity, maximum convective vertical velocity, and diameter are consistent with previous studies of hurricane convection. Most cores are superimposed upon relatively weak mesoscale ascent. The mean eyewall (rainband) updraft core exhibits small, but statistically significant, positive total buoyancy below 4 km (between 2 and 5 km) and a modest increase in vertical velocity with altitude. The mean downdraft core not superimposed upon stronger mesoscale ascent also exhibits positive total buoyancy and a slight decrease in downward vertical velocity with decreasing altitude. Buoyant updraft cores cover less than 5% of the total area in each region but accomplish ~40% of the total upward transport. A one-dimensional updraft model is used to elucidate the relative roles played by buoyancy, vertical perturbation pressure gradient forces, water loading, and entrainment in the vertical acceleration of ordinary updraft cores. Small positive total buoyancy values are found to be more than adequate to explain the vertical accelerations observed in updraft core strength, which implies that ordinary vertical perturbation pressure gradient forces are directed downward, opposing the positive buoyancy forces. Entrainment and water loading are also found to limit updraft magnitudes. The observations support some aspects of both the hot tower hypothesis and symmetric moist neutral ascent, but neither concept appears dominant. Buoyant convective updrafts, however, are integral components of the hurricane's transverse circulation.

Eastin, M.D., W.M. Gray, and P.G. Black. Buoyancy of convective vertical motions in the inner core of intense hurricanes, Part II: Case studies. Monthly Weather Review, 133(1):209-227 (2005).

This is the second of two papers on the buoyancy of convective vertical motions in the inner core of intense hurricanes. This paper uses extensive airborne radar, dropwindsonde, and flight-level observations in Hurricanes Guillermo (1997) and Georges (1998) to illustrate typical azimuthal distribution of buoyant convection and demonstrate that the low-level eye can be an important source region for buoyant eyewall convection. In both hurricanes, eyewall vertical velocity and radar reflectivity are asymmetric and exhibit persistent relationships with the direction of the environmental vertical wind shear. Mesoscale vertical motions exhibit a wavenumber-1 structure with maximum ascent downshear and weak descent upshear. The mesoscale reflectivity maxima are located left-of-shear. Buoyant eyewall updraft cores and transient convective-scale reflectivity cells are predominantly downshear and left-of-shear. Most eyewall downdraft cores that transport significant mass downward are located upshear. Negative buoyancy was most common in left-of-shear downdrafts, with positive buoyancy dominant in upshear downdrafts. Inward-spiraling rainbands located outside the eyewall exhibit upband/downband asymmetries. Upband segments contain more convective reflectivity cells and buoyant updraft cores than the more stratiform downband segments. Equal numbers of downdraft cores are found upband and downband, but the majority exhibit negative buoyancy. Several buoyant updraft cores encountered in the midlevel eyewall exhibit equivalent potential temperatures (theta_e) much higher than the theta_e observed in the low-level eyewall, but equivalent to the theta_e observed in the low-level eye. Asymmetric low-wavenumber circulations appear responsible for exporting the high-theta_e eye air into the relatively low-theta_e eyewall and generating the locally buoyant updraft cores. Implications of these results upon conceptual models of hurricane structure are discussed. Three mechanisms, whereby an ensemble of asymmetric buoyant convection could contribute to hurricane evolution, are also discussed.

Enfield, D.B., and S.-K. Lee. The heat balance of the western hemisphere warm pool. Journal of Climate, 18(4):2662-2681 (2005).

The thermodynamic development of the western hemisphere warm pool and its four geographic subregions are analyzed. The subregional warm pools of the eastern North Pacific and equatorial Atlantic are best developed in the boreal spring, while in the Gulf of Mexico and Caribbean, the highest temperatures prevail during the early and late summer, respectively. For the defining isotherms chosen (27.5°, 28.0°, 28.5°C) the warm pool depths are similar to the mixed-layer depth (20-40 m) but are considerably less than the Indo-Pacific warm pool depth (50-60 m). The heat balance of the WHWP subregions is examined through two successive types of analysis: first by considering a changing volume ("bubble") bounded by constant temperature wherein advective fluxes disappear and diffusive fluxes can be estimated as a residual, and second by considering a slab layer of constant dimensions with the bubble diffusion estimates as an additional input and the advective heat flux divergence as a residual output. From this sequential procedure it is possible to disqualify as being physically inconsistent four of seven surface heat flux climatologies: the NCEP-NCAR reanalysis (NCEP1) and the ECMWF 15-yr global reanalysis (ERA-15) because they yield a nonphysical diffusion of heat into the warm pools from their cooler surroundings, and the unconstrained da Silva and Southampton datasets because their estimated diffusion rates are inconsistent with the smaller rates of the better understood Indo-Pacific warm pool when the bubble analysis is applied to both regions. The remaining surface flux datasets of da Silva and Southampton (constrained) and Oberhuber have a much narrower range of slab surface warming (+25 � 5 W m^-2) associated with bubble residual estimates of total diffusion of -5 to -20 W m^-2 (�5 W m^-2) and total advective heat flux divergence of -2 to -14 W m^-2 (�5 W m^-2). The latter are independently confirmed by direct estimates using wind stress data and drifters for the Gulf of Mexico and eastern North Pacific subregions.

Etherton, B.J., and S.D. Aberson. Ensemble based data assimilation of observations of Hurricane Humberto. Preprints, 9th Symposium on Integrated Observing and Assimilation Systems for the Atmosphere, Oceans, and Land Surface, San Diego, CA, January 9-13, 2005. American Meteorological Society, Boston, 5 pp. (2005).

No abstract.

Feely, R.A., and R. Wanninkhof. Global repeat hydrographic/CO₂/tracer surveys in support of CLIVAR and global carbon cycle objectives: Carbon inventories and fluxes, pp. 149-168. In Annual Report on the State of the Ocean and Ocean Observing System for Climate (FY-2004), D.M. Stanitski (ed.). NOAA Office of Climate Observation, Silver Spring, MD, 422 pp. (2005).

No abstract.

Feely, R.A., and R. Wanninkhof. The global ocean carbon cycle: Inventories, sources, and sinks, pp. 42-56. In Annual Report on the State of the Ocean and Ocean Observing System for Climate (FY-2004), D.M. Stanitski (ed.). NOAA Office of Climate Observation, Silver Spring, MD, 422 pp. (2005).

The ocean plays a major role in the global carbon cycle as it is a vast reservoir of carbon, naturally exchanges carbon with the atmosphere, and consequently takes up a substantial portion of anthropogenic carbon from the atmosphere. In response to the need for an integrated investigation of the carbon cycle in the oceans, the CLIVAR/CO₂ Repeat Hydrography and NOAA Underway pCO₂ Measurements Programs were established to document the trends in carbon uptake and transport in the global oceans. The CLIVAR/CO₂ Repeat Hydrography Program consists of a systematic re-occupation of select hydrographic sections to quantify global changes in storage and transport of heat, fresh water, carbon dioxide (CO₂), chlorofluorocarbon tracers and related parameters. Three North Atlantic cruises in 2003 marked the beginning of the U.S. effort by reoccupying selected hydrographic sections on decadal time-scales. Early results from these cruises showed significant changes in oxygen and carbon dioxide and several other measurable parameters since the last global survey in the 1990s. The increases of DIC in the Subtropical Mode waters (STMW) are greater than expected from invasion of anthropogenic CO₂ from the atmosphere and may be the result of decadal changes in the local circulation in the North Atlantic.

Feely, R.A., L.D. Talley, G.C. Johnson, C.L. Sabine, and R.H. Wanninkhof. Repeat hydrography cruises reveal chemical changes in the North Atlantic. EOS, Transactions, American Geophysical Union, 86(42):399, 404-405 (2005).

The U.S. contribution to a large international effort to document long-term trends in carbon storage and transport in the global oceans by reoccupying selected hydrographic sections on decadal timescales began with three North Atlantic cruises in 2003. The initial results from these reoccupation cruises have shown significant long-term changes in oxygen, carbon dioxide (CO₂), and several other measurable parameters since the last global survey, which occurred in 1993. The ocean has a memory of the climate system and is second only to the Sun in affecting variability in the seasons and long-term climate change. The ocean stores an estimated 1000 times more heat than the atmosphere, and 50 times more carbon. Additionally, the key to possible abrupt climate change may lie in deep-ocean circulation.

Garzoli, S.L., and R.L. Molinari. Surface drifter program, pp. 169-174. In Annual Report on the State of the Ocean and Ocean Observing System for Climate (FY-2004), D.M. Stanitski (ed.). NOAA Office of Climate Observation, Silver Spring, MD, 422 pp. (2005).

No abstract.

Goes, M., R.L. Molinari, I. da Silveira, and I. Wainer. Retroflections of the North Brazil Current during February 2002. Deep-Sea Research, Part I, 52(4):647-667 (2005).

Retroflections of the North Brazil Current (NBC) are examined using observational data collected in the western tropical Atlantic between 35°W-44°W and 11°S-7°N. Acoustic Doppler Current profiler, conductivity temperature depth oxygen and expendable bathythermograph data were obtained during a cruise conducted in February 2002. The water column was separated into two layers, the upper layer from the sea-surface to the 24.5 isopycnal and lower layer from the 24.5 to the 26.8 isopycnal. The upper layer includes the NBC, the South Equatorial Current, the North Equatorial Countercurrent (NECC) and a portion of the Equatorial Undercurrent (EUC). The lower layer includes the North Brazil Undercurrent (NBUC), the South Equatorial Undercurrent (SEUC), the North Equatorial Undercurrent (NEUC) and another portion of the EUC. With respect to earlier work, the data show that: (1) the SEUC is primarily fed by waters from a recirculation gyre on its northern boundary with some minor transport retroflecting from the NBUC; (2) the EUC is fed primarily by southern hemisphere waters that retroflect from the NBC, but there is some northern hemisphere water in the near surface flow that connects the EUC and NEUC during this cruise; (3) the NECC during this cruise has no connection to the NBC and is fed by northern hemisphere waters originating in the North Equatorial Current; and (4) the majority of the upper layer NBC that crosses 44°W does not appear to retroflect from the boundary farther north to return equatorward. New results include: (1) quantification, for this period, of the amount of transport in the single current core at 44°W that is comprised of waters from the southern (9.2 Sv) and northern hemispheres (5.2 Sv); (2) demonstration that the single core of eastward flow at 44°W and 41°W separates into the NEUC and EUC by 35°W, with the former composed of northern hemisphere waters and the latter southern hemisphere waters; (3) demonstration that the precursor to the EUC (NEUC) at 44°W and 41°W accelerates (decelerates) by 35°W; and (4) depiction of the potential vorticity (PV) field showing that the PV front at 44°W has separated into a front of higher PV values coincident with NEUC and a low PV core at 35°W coincident with the EUC.

Goodwin, K.D. Assay and remote sensor development for molecular biological water quality monitoring. Proceedings, 2004 National Beaches Conference, San Diego, CA, October 13-14, 2004. Environmental Protection Agency (EPA-823-R-05-001), 268-273 (2005).

Molecular tools are a promising means to provide rapid and accurate monitoring of coastal water quality. We are developing three nucleic acid hybridization assays to identify and monitor nuisance organisms (bacterial and algal) in coastal waters. A microplate assay returns a rapid colorimetric result and provides moderate throughput at relatively low cost. A Luminex Xmap system rapidly provides high throughput and the potential to screen for a large number of targets simultaneously. Electrochemical detection is a cutting edge technology suitable to the size, power, and cost requirements of remote sensing. An overview of the development and application of these technologies will be presented.

Goodwin, K.D., S.A. Cotton, G. Scorzetti, and J.W. Fell. A DNA hybridization assay to identify toxic dinoflagellates in coastal waters: Detection of Karenia Brevis in the Rookery Bay National Estuarine Research Reserve. Harmful Algae, 4(2):411-422 (2005).

A DNA hybridization assay was developed in microtiter plate format to detect the presence of toxic dinoflagellates in coastal waters. Simultaneous detection of multiple species was demonstrated using Karenia brevis, Karenia mikimotoi, and Amphidinium carterae. Molecular probes were designed to detect both K. brevis and K. mikimotoi and to distinguish between these two closely related species. The assay was used to detect K. brevis in coastal waters collected from the Rookery Bay National Estuarine Research Reserve. Assay results were verified by species-specific PCR and sequence analysis. The presence/absence of K. brevis was consistent with microscopic observation. Assay sensitivity was sufficient to detect K. brevis in amounts defined by a regional monitoring program as "present" (<1000 cells/L). The assay yielded quick colorimetric results, used a single hybridization temperature, and conserved the amount of genomic DNA utilized by employing one set of PCR primers. The microplate assay provides a useful tool to quickly screen large sample sets for multiple target organisms.

Goodwin, K.D., R. Tokarczyk, F.C. Stephens, and E.S. Saltzman. Description of toluene inhibition of methyl bromide biodegradation in seawater and isolation of a marine toulene oxidizer that degrades methyl bromide. Applied and Environmental Microbiology, 71(7):3495-3503 (2005).

Methyl bromide (CH₃Br) and methyl chloride (CH₃Cl) are important precursors for destruction of stratospheric ozone, and oceanic uptake is an important component of the biogeochemical cycle of these methyl halides. In an effort to identify and characterize the organisms mediating halocarbon biodegradation, we surveyed the effect of potential cometabolic substrates on CH₃Br biodegradation using a ¹³CH₃Cl incubation technique. Toluene (160 to 200 nM) clearly inhibited CH₃Br and CH₃Cl degradation in seawater samples from the North Atlantic, North Pacific, and Southern Oceans. Furthermore, a marine bacterium able to co-oxidize CH₃Br while growing on toluene was isolated from subtropical western Atlantic seawater. The bacterium, Oxy6, was also able to oxidize o-xylene and the xylene monooxygenase (XMO) pathway intermediate 3-methylcatechol. Patterns of substrate oxidation, lack of acetylene inhibition, and the inability of the toluene 4-monooxygenase (T4MO)-containing bacterium Pseudomonas mendocina KR1 to degrade CH₃Br ruled out participation of the T4MO pathway in Oxy6. Oxy6 also oxidized a variety of toluene (TOL) pathway intermediates such as benzyl alcohol, benzylaldehyde, benzoate, and catechol, but the inability of Pseudomonas putida mt-2 to degrade CH₃Br suggested that the TOL pathway might not be responsible for CH₃Br biodegradation. Molecular phylogenetic analysis identified Oxy6 to be a member of the family Sphingomonadaceae related to species within the Porphyrobacter genus. Although some Sphingomonadaceae can degrade a variety of xenobiotic compounds, this appears to be the first report of CH₃Br degradation for this class of organism. The widespread inhibitory effect of toluene on natural seawater samples and the metabolic capabilities of Oxy6 indicate a possible link between aromatic hydrocarbon utilization and the biogeochemical cycle of methyl halides.

Hankin, S.C., R.A. Feely, A. Kozyr, and T.-H. Peng. An end-to-end management system for ocean pCO₂ measurements, pp. 181-186. In Annual Report on the State of the Ocean and Ocean Observing System for Climate (FY-2004), D.M. Stanitski (ed.). NOAA Office of Climate Observation, Silver Spring, MD, 422 pp. (2005).

No abstract.

Hitchcock, G.L., T.N. Lee, P.B. Ortner, S.R. Cummings, C.R. Kelble, and E. Williams. Property fields in a Tortugas eddy in the southern Straits of Florida. Deep-Sea Research, Part I, 52(12):2195-2213 (2005).

Sea surface temperature imagery, ship-based surveys, and moored current meters described the passage of a Tortugas eddy as it moved east at ca. 6 km day^-1 through the southern Straits of Florida (SSF). In mid-April 1999, the eddy SST signature extended across half the width of the Straits. While in the western SSF, the eddy center was ca. 30 km seaward of the outer reef. The upper pycnocline, the subsurface chlorophyll a maximum (SCM), and nutricline shoaled from ca. 80 m at the eddy edge to <60 m at the center. Maximum chlorophyll-a concentrations in the SCM were highest near the eddy center, at 1 mg m^-3, although the depth-integrated concentrations (mg m^-2) were similar across the feature. Nutrient-density relationships show nitrate+nitrite, phosphate, and silicate decreased to detection limits at sigma_t <25.0; the SCM was centered near this isopycnal surface. As the Eddy passed Looe Key (81.5°W), the alongshore currents reversed to the west. During this period high-nutrient, cool waters shoaled near the bottom on the outer reef. By early May, the eddy SST signature was compressed into a thin band of cool surface waters off the middle to upper Keys. As the feature moved towards shore in the middle to upper Florida Keys, the nitrate+nitrite and chlorophyll concentrations increased in bottom waters along the outer reef. Processes such as internal tidal bores and breaking internal waves are likely responsible for delivering nutrients from Tortugas eddies to the outer reef in the middle to upper Keys.

Hu, C., J.R. Nelson, E. Johns, Z. Chen, R.H. Weisberg, and F.E. Muller-Karger. Mississippi River water in the Florida Straits and in the Gulf Stream off Georgia in summer 2004. Geophysical Research Letters, 32(14):L14606, doi:10.1029/2005GL022942 (2005).

A coherent plume from the Mississippi River was detected in MODIS imagery in July-October 2004 extending from the eastern Gulf of Mexico into the Florida Straits (FS), and reaching the Gulf Stream (GS) off Georgia. The plume was sampled from ships in the FS and the GS. In early August, the plume was about 10-20 km wide in the western FS and about 50 km wide off Georgia. The FS ship survey (16-26 August) documented a 50 km, 10-20 m deep band with anomalies in surface salinity (-0.8), temperature (0.5°C), and surface chlorophyll concentration (2x) relative to FS waters outside the plume. Nutrient concentrations were only slightly higher in the FS plume and there was no apparent increase in colored dissolved organic matter. We estimate that the plume carried some 23% (~2778 m³ s^-1) of the Mississippi River discharge between July and September 2004 into the GS.

Hu, C., F.E. Muller-Karger, C. Taylor, K.L. Carder, C. Kelble, E. Johns, and C.A. Heil. Red tide detection and tracing using MODIS fluorescence data: A regional example in southwest Florida coastal waters. Remote Sensing of Environment, 97(3):311-321 (2005).

Near real-time data from the MODIS satellite sensor was used to detect and trace a harmful algal bloom (HAB), or red tide, in southwest Florida coastal waters from October to December 2004. MODIS fluorescence line height (FLH in W m^-2 m^-1 sr^-1) data showed the highest correlation with near-concurrent in situ chlorophyll-a concentration (Chl in mg m^-3). For Chl ranging between 0.4 to 4 mg m^-3 the ratio between MODIS FLH and in situ Chl is about 0.1 W m^-2 m^-1 sr^-1 per mg m^-3 chlorophyll (Chl = 1.255 (FLH x 10)^0.86, r = 0.92, n = 77). In contrast, the band-ratio chlorophyll product of either MODIS or SeaWiFS in this complex coastal environment provided false information. Errors in the satellite Chl data can be both negative and positive (3-15 times higher than in situ Chl), and these data are often inconsistent either spatially or temporally due to interferences of other water constituents. The red tide that formed from November to December 2004 off southwest Florida was revealed by MODIS FLH imagery and was confirmed by field sampling to contain medium (10⁴ to 10⁵ cells L^-1) to high (>10⁵ cells L^-1) concentrations of the toxic dinoflagellate Karenia brevis. The FLH imagery also showed that the bloom started in mid-October south of Charlotte Harbor, and that it developed and moved to the south and southwest in the subsequent weeks. Despite some artifacts in the data and uncertainty caused by factors such as unknown fluorescence efficiency, our results show that the MODIS FLH data provide an unprecedented tool for research and managers to study and monitor algal blooms in coastal environments.

Johns, E., R.H. Smith, P.B. Ortner, T.N. Lee, C.R. Kelble, and N. Melo. Real-time oceanographic and meteorological observations in the Florida Keys National Marine Sanctuary. Proceedings, 2005 Florida Bay and Adjacent Marine Systems Science Conference, Duck Key, FL, December 11-14, 2005. University of Florida, 133-134 (2005).

No abstract.

Johns, E., R.H. Smith, P.B. Ortner, T.N. Lee, C.R. Kelble, and N. Melo. Salinity variability in south Florida coastal waters, 1995-2005. Proceedings, 2005 Florida Bay and Adjacent Marine Systems Science Conference, Duck Key, FL, December 11-14, 2005. University of Florida, 135-136 (2005).

No abstract.

Kelble, C.R., P.B. Ortner, G.L. Hitchcock, and J.N. Boyer. Attenuation of photosynthetically available radiation (PAR) in Florida Bay: Potential for light limitation of primary producers. Estuaries, 28(4):560-571 (2005).

Light attenuation in marine ecosystems can limit primary production and determine the species composition and abundance of primary producers. In Florida Bay, the importance of understanding the present light environment has heightened as major upstream water management restoration projects have been proposed and some are already being implemented. We analyzed a two-yearr (2001-2003) data set of the light attenuation coefficient (K_t) and its principal components (water, chromophoric dissolved organic matter [CDOM], tripton, phytoplankton) obtained at 40 stations within Florida Bay, calibrated synoptic underway data to produce high spatial resolution maps, examined the potential for light limitation, and quantified the individual effect of each component upon light attenuation. Tripton was the dominant component controlling light attenuation throughout Florida Bay, whereas the contribution of chlorophyll a and CDOM to K_t was much smaller in all regions of Florida Bay. It was possible to accurately estimate the light attenuation coefficient from component concentrations, using either a mechanistic or a statistical model with root mean square errors of 0.252 or 0.193 m^-1, respectively. Compared to other estuaries, Florida Bay had the lowest overall K_t and the greatest relative contribution from tripton. Comparing the recent data to a study of Florida Bay's light environment conducted in 1993-1994, we found that overall water clarity in the Bay increased significantly, indicated by a nearly three-fold decrease in K_t, as a result of lower tripton concentrations, although the percent contribution of each of the components to K_t is unchanged. Only the northwest corner of Florida Bay, an area comprised of approximately 8% of the Bay's total area, was found on average to have sufficient light attenuation to limit the growth of seagrasses. This is much less extensive than in 1993-1994, when seagrass growth was potentially limited by light at over 50% of the stations sampled.

Kelble, C.R., E.M. Johns, P.B. Ortner, W.K. Nuttle, T.N. Lee, C.D. Hittle, and R.H. Smith. Salinity patterns of Florida Bay. Proceedings, 2005 Florida Bay and Adjacent Marine Systems Science Conference, Duck Key, FL, December 11-14, 2005. University of Florida, 137-138 (2005).

No abstract.

Kim, D.-O., K. Lee, S.-D. Choi, H.-S. Kang, J.-Z. Zhang, and Y.-S. Chang. Determination of diapycnal diffusion rates in the upper thermocline in the North Atlantic Ocean using sulfur hexafluoride. Journal of Geophysical Research, 110(C10):C10010, doi:10.1029/2004JC002835 (2005).

The apparent diapycnal diffusivity below the wind-driven surface mixed layer of the ocean was determined in an anticyclonic eddy in the eastern North Atlantic using sulfur hexafluoride (SF₆) tracer data collected in June 1998. In this tracer experiment, the downward penetration of SF₆ was measured for three weeks following the deliberate injection of SF₆ in the surface mixed layer. The resulting data were used to constrain the one-dimensional Fickian diffusion model to estimate the diapycnal diffusivity. The model also includes the lateral diffusion component so that it can more accurately represent the time evolution of the SF₆ concentrations along the isopycnal surface. This affects the estimation of the diapycnal diffusivity. For the upper thermocline immediately below the surface mixed layer we estimated the diapycnal diffusivity for the three-week period as 0.3 � 0.2 cm² s-1 at a buoyancy frequency of 8.2 cph.

Knabb, R.D., J.-G. Jiing, C.W. Landsea, and W.R. Seguin. The Joint Hurricane Testbed (JHT): Progress and future plans. Preprints, 9th Symposium on Integrated Observing and Assimilation Systems for the Atmosphere, Oceans, and Land Surface, San Diego, CA, January 9-13, 2005. American Meteorological Society, Boston, 3 pp. (2005).

No abstract.

LaGier, M.J., C.A. Scholin, J.W. Fell, J. Wang, and K.D. Goodwin. An electrochemical RNA hybridization assay for detection of the fecal indicator bacterium Escherichia coli. Marine Pollution Bulletin, 50(11):1251-1261(2005).

Monitoring waters for indicator bacteria is required to protect the public from exposure to fecal pollution. Our proof-of-concept study describes a method for detecting fecal coliforms. The coliform Escherichia coli was used as a model fecal indicator. DNA probe-coated magnetic beads in combination with the electrochemical monitoring of the oxidation state of guanine nucleotides should allow for direct detection of bacterial RNA. To demonstrate this concept, we used voltammetry in connection with pencil electrodes to detect isolated E. coli 16S rRNA. Using this approach, 10⁷ cells of E. coli were detected in a quantitative, reproducible fashion in 4 h. Detection was achieved without a nucleic acid amplification step. The specificity of the assay for coliforms was demonstrated by testing against a panel of bacterial RNA. We also show that E. coli RNA can be detected directly from cell extracts. The method could be used for on-site detection and shows promise for adaptation into automated biosensors for water-quality monitoring.

Landsea, C.W. Hurricanes and global warming. Nature, 438(7071):E11-E12 (2005).

No abstract.

Lee, S.-K., D.B. Enfield, and C. Wang. Ocean general circulation model sensitivity experiments on the annual cycle of Western Hemisphere warm pool. Journal of Geophysical Research, 110(C9):C09004, doi:10.1029/2004JC002640 (2005).

A series of ocean general circulation (OGCM) model experiments is carried out using a hybrid coordinate ocean model (HYCOM) to determine the annual cycle of Western Hemisphere Warm Pool (WHWP) heat budget and to assess the appropriateness of commonly used surface flux data sets in driving HYCOM simulations of the WHWP. Among the eight surface heat flux data sets addressed in this study, we find that the simulated SST is closest to the observations when the Southampton constrained (SHC) heat flux data are used, consistent with the conclusion of the data-based study of Enfield and Lee (2005). However, the modeled thermocline water is warmer and its stratification is weaker than observed regardless of the surface heat flux data used, possibly because of the low vertical resolution of the model used in this study. A preliminary heat budget analysis suggests that the surface net heat flux serves as the dominant forcing mechanism in the WHWP regions except in the equatorial Atlantic, where advective processes associated with the equatorial cold tongue are more important. A process of winter overturning that warms the upper layer by convection marks the Gulf of Mexico, while horizontal advection is of little importance there. The eastern north Pacific and Caribbean are affected significantly by vertical and horizontal advection during the onset and peak phases, slowing down the warming considerably.

Lee, T.N., E.M. Johns, N. Melo, R.H. Smith, P.B. Ortner, D. Smith, and N. Smith. On Florida Bay hypersalinity and water exchange. Proceedings, 2005 Florida Bay and Adjacent Marine Systems Science Conference, Duck Key, FL, December 11-14, 2005. University of Florida, 123-124 (2005).

No abstract.

Legeais, J.-F., S. Speich, M. Arhan, I. Ansorge, E. Fahrbach, S.L. Garzoli, and A. Klepikov. The baroclinic transport of the Antarctic Circumpolar Current south of Africa. Geophysical Research Letters, 32(24):L24602, doi:10.1029/2005GL023271 (2005).

Five hydrographic transects at nominal longitudes 0°E and 30°E, and 14 expendable bathythermograph (XBT) sections near the former longitude are used to study the baroclinic transport of the Antarctic Circumpolar Current (ACC) between Africa and Antarctica. The bottom-referenced geostrophic transport between the Subtropical Front and the ACC Southern Boundary is 147 � 10 Sv. Estimating the transport from the XBTs using a technique previously employed south of Australia proves delicate because of an irregular bathymetry and water mass variations. It nevertheless confirms ACC transports around 150 Sv. Gathering these and other estimates from the Atlantic sector suggests that, while North Atlantic Deep Water is injected in the current west of 35°W, a partially compensating loss of Deep Circumpolar Water occurs east of this longitude. Another transport increase from 0°E to 30°E might reflect southward transfer across the Subtropical Front south of the Agulhas retroflection.

Li, J.-L., D.E. Waliser, J.H. Jiang, D.L. Wu, W. Read, J.W. Waters, A.M. Tompkins, L.J. Donner, J.-D. Chern, W.-K. Tao, R. Atlas, Y. Gu, K.N. Liou, A. Del Genio, M. Khairoutdinov, and A. Gettelman. Comparisons of EOS MLS cloud ice measurements with ECMWF analyses and GCM simulations: Initial results. Geophysical Research Letters, 32(18):L18710, doi:10.1029/2005GL023788 (2005).

To assess the status of global climate models (GCMs) in simulating upper-tropospheric ice water content (IWC), a new set of IWC measurements from the Earth Observing System's Microwave Limb Sounder (MLS) are used. Comparisons are made with ECMWF analyses and simulations from several GCMs, including two with multi-scale-modeling framework. For January 2005 monthly and daily mean values, the spatial agreement between MLS and ECMWF is quite good, although MLS estimates are higher by a factor of 2-3 over the western Pacific, tropical Africa, and South America. For the GCMs, the model-data agreement is within a factor of 2-4 with larger values of disagreement occurring over eastern Pacific and Atlantic ITCZs, tropical Africa, and South America. The implications arising from sampling and uncertainties in the observations, the modeled values, and their comparison are discussed. These initial results demonstrate the potential usefulness of this data set for evaluating GCM performance and guiding development efforts.

Li, Q.P., J.-Z. Zhang, F.J. Millero, and D.A. Hansell. Continuous colorimetric determination of trace ammonium in seawater with a long-path liquid waveguide capillary cell. Marine Chemistry, 96(1-2):73-85 (2005).

An automated method for routine determination of nanomolar ammonium in seawater has been developed using segmented flow analysis coupled with a 2-m-long liquid waveguide capillary cell. Conventional photometric detector and autosampler were modified for this method. The optimal concentrations of the reagents and parameters for the development of indophenol blue are discussed. The method has low detection limit (5 nM), high precision (5% at 10-100 nM) and the advantage of rapid analysis of a large number of samples. The method has been used to examine the distribution of ammonium in Florida Bay and Biscayne Bay.

Lumpkin, R., and Z. Garraffo. Evaluating the decomposition of tropical Atlantic drifter observations. Journal of Atmospheric and Oceanic Technology, 22(9):1403-1415 (2005).

Because the tropical Atlantic is characterized by regions of strong seasonal variability that have been sampled inhomogeneously by surface drifters, Eulerian averages of these Lagrangian observations in spatially fixed bins may be aliased. In the Pacific, this problem has been circumvented by first calculating seasonal or monthly means. In the Atlantic, such an approach is of limited value because of the relatively sparse database of drifter observations. As an alternative, a methodology is developed in which drifter-observed currents and sea surface temperatures are grouped into bins and, within each bin, simultaneously decomposed into a time-mean, annual and semiannual harmonics, and an eddy residual with a nonzero integral time scale. The methodology is evaluated using a temporally homogeneous SST product and in situ SST observations, and also using simulated drifter observations in an eddy-resolving model of the Atlantic Ocean. These analyses show that, compared to simple bin averaging, the decomposition developed herein yields significantly improved estimates of time-mean values in regions of strong seasonal variability. The methodology can also successfully estimate the distribution of the seasonal harmonics' amplitude and phase throughout much of the tropical Atlantic.

Lumpkin, R., and S.L. Garzoli. Near-surface circulation in the tropical Atlantic Ocean. Deep-Sea Research, Part I, 52(3):495-518 (2005).

A recent data set of surface drifter observations in the tropical Atlantic Ocean is analyzed with a methodology that groups the observations into bins and, within each bin, simultaneously decomposed them into a time-mean, annual and semiannual harmonics, and an eddy residual with non-zero integral time scale. Features of the time-mean circulation and its seasonal variations are resolved at unprecedented scales, for both total and Ekman-removed velocities. The drifter observations reveal the branches of the South Equatorial Current (SEC) which merge with the North Brazil Current (NBC), correlated annual fluctuations in the strengths of the NBC retroflection, western North Equatorial Countercurrent (NECC) and SEC, and flow along the Guyana coast, and strong semiannual variations in the equatorial band of the central basin. Conduits are traced which link seasonal variations of the equatorial current system's strength with the northern and southern hemisphere subtropical gyres. These findings update key results of the two decade-old SEQUAL/FOCAL programs, and allow generation of a new monthly climatology of near-surface currents in the tropical Atlantic Ocean.

Majumdar, S.J., S.D. Aberson, C.H. Bishop, R. Buizza, M.S. Peng, and C.A. Reynolds. A comparison of adaptive observing guidance for Atlantic tropical cyclones. European Centre for Medium-Range Weather Forecasts, Technical Memorandum No. 482, 24 pp. (2005).

Airborne adaptive observations have been collected for more than two decades in the neighborhood of tropical cyclones, to attempt to improve short-range forecasts of cyclone track. However, only simple subjective strategies for adaptive observations have been used, and the utility of objective strategies to improve tropical cyclone forecasts remains unexplored. Two objective techniques that have been used extensively for mid-latitude adaptive observing programs, and the current strategy based on the ensemble deep-layer mean (DLM) wind variance, are compared quantitatively using two metrics. The ensemble transform Kalman filter (ETKF) uses ensembles from NCEP and ECMWF. Total-energy singular vectors (TESVs) are computed by ECMWF and the Naval Research Laboratory, using their respective global models. Comparisons of 78 guidance products for two-day forecasts during the 2004 Atlantic hurricane season are made, on both continental and localized scales relevant to synoptic surveillance missions. The ECMWF and NRL TESV guidance identifies similar large-scale target regions in 90% of the cases, but are less similar to each other in the local tropical cyclone environment (56% of the cases) with a more stringent criterion for similarity. For major hurricanes, all techniques usually indicate targets close to the storm center. For weaker tropical cyclones, the TESV guidance selects similar targets to those from the ETKF (DLM wind Variance) in only 30% (20%) of the cases. ETKF guidance using the ECMWF ensemble is more like that provided by the NCEP ensemble (and DLM wind variance) for major hurricanes than for weaker tropical cyclones. Minor differences in these results occur when a different metric based on the ranking of fixed storm-relative regions is used.

Mason, D.M., T.B. Johnson, C.J. Harvey, J.F. Kitchell, S.T. Schram, C.R. Bronte, M.H. Hoff, S.T. Lozano, A.S. Trebitz, D.R. Schreiner, E.C. Lamon, and T. Hrabik. Hydroacoustic estimates of abundance and spatial distribution of pelagic prey fishes in western Lake Superior. Journal of Great Lakes Research, 31(4):426-438 (2005).

Lake herring (Coregonus artedi) and rainbow smelt (Osmerus mordax) are a valuable prey resource for the recovering lake trout (Salvelinus namaycush) in Lake Superior. However, prey biomass may be insufficient to support the current predator demand. In August 1997, we assessed the abundance and spatial distribution of pelagic coregonines and rainbow smelt in western Lake Superior by combining a 120 kHz split beam acoustics system with midwater trawls. Coregonines comprised the majority of the midwater trawl catches and the length distributions for trawl caught fish coincided with estimated sizes of acoustic targets. Overall mean pelagic prey fish biomass was 15.56 kg ha^-1 with the greatest fish biomass occurring in the Apostle Islands region (27.98 kg ha^-1), followed by the Duluth Minnesota region (20.22 kg ha^-1), and with the lowest biomass occurring in the open waters of western Lake Superior (9.46 kg ha^-1). Biomass estimates from hydroacoustics were typically 2-134 times greater than estimates derived from spring bottom trawl surveys. Prey fish biomass for Lake Superior is about order of magnitude less than acoustic estimates for Lakes Michigan and Ontario. Discrepancies observed between bioenergetics-based estimates of predator consumption of coregonines and earlier coregonine biomass estimates may be accounted for by our hydroacoustic estimates.

McNeil, C., D. Katz, R. Wanninkhof, and B. Johnson. Continuous shipboard sampling of gas tension, oxygen, and nitrogen. Deep-Sea Research, Part I, 52(9):1767-1785 (2005).

A novel shipboard gas tension device (GTD) that measures total dissolved air pressure in ocean surface waters is described and demonstrated. In addition, an improved method to estimate dissolved N₂ levels from simultaneous measurements of gas tension, dissolved O₂, water temperature, and salinity is described. Other than a flow-through plenum, the shipboard GTD is similar to the previously described moored-mode GTD (McNeil et al., 1995, Deep-Sea Research, Part I, 42:819-826). The plenum has an integrated water-side screen to protect the membrane and prevent the membrane from flexing in super-saturated near surface waters. The sampling scheme uses a well mixed and thermally insulated 15 L container that is flushed by the ship's seawater intake at a rate of 3-15 L min^-1. Dissolved gas sensors are placed inside this container and flushed with a small recirculation pump. Laboratory data that characterize the response of the modified GTD are presented. The modified GTD has a constant, isothermal, characteristic (e-folding) response time of typically 11�2 min at 20°C. The response time decreases with increasing temperature and varies by �35% over a temperature range of 5-35°C. Results of field measurements, collected on the R/V Brown between New York and Puerto Rico during September 2002, are presented and provide the first look at co-variability in surface ocean N₂, O₂, and CO₂ levels over horizontal length scales of several kilometers. Dissolved N₂ concentrations decreased by approximately 16% as the ship sailed from the colder northern continental shelf waters, across the Gulf Stream, and into the warmer northwestern Atlantic Ocean. Historical database measurements, buoy time series, and satellite imagery, are used to aid interpretation of the dissolved gas levels.

Meinen, C.S. Meridional extent and interannual variability of the Pacific Ocean tropical-subtropical warm water exchange. Journal of Physical Oceanography, 35(3):323-335 (2005).

Altimetric observations of sea surface height anomaly (SSHA) from the TOPEX/Poseidon and ERS satellites, hydrography, and the ECMWF and Florida State University wind products are used to track warm water (>20°C) as it is exchanged between the equatorial Pacific Ocean and the higher latitudes during 1993-2003. The large El Ni�o event of 1997-1998 resulted in a significant discharge of warm water toward the higher latitudes within the interior of the Pacific Ocean. The exchange of anomalous warm water volume with the Northern Hemisphere appears to be blocked under the intertropical convergence zone, consistent with most current ideas on the time-mean tropical-subtropical exchange. Little of the warm water discharged northward across 5° and 8°N during the 1997-1998 El Ni�o event could be traced as far as 10°N. To the south, however, these anomalous volumes of warm water were visible at least as far as 20 S, primarily in the longitudes around 130°-160°W. In both hemispheres most of the warm water appeared to flow westward before returning to the Tropics during the recharge phase of the El Ni�o-La Ni�a cycle. The buildup of warm water in the Tropics before the 199798 El Ni�o is shown to be fed primarily by warm water drawn from the region in the western Pacific within 5°S-15°N. The exchange cycle between the equatorial band and the higher latitudes north of the equator leads the cycle in the south by 6-8 months. These results are found in all three datasets used herein, hydrography, altimetric observations of SSHA, and Sverdrup transports calculated from multiple wind products, which demonstrates the robustness of the results.

Meinen, C.S. Temporal sampling: How many sections are needed to quantify the mean transport and structure of a meandering current? Journal of Atmospheric and Oceanic Technology, 22(4):476-489 (2005).

Two years of observations from an array of 16 inverted echo sounders deployed south of Australia near 51°S, 143.5°E are combined with hydrographic observations from the region to estimate the differences in baroclinic transport, as well as temperature and velocity structure, that result from trying to estimate the true mean using a limited number of snapshot sections. The results of a Monte Carlo-type simulation suggest that over a 350-km distance, completely spanning the Subantarctic Front (SAF) at most times, a minimum of six temporally independent sections would be required to determine the baroclinic transport mean (surface to 4000 db) of the observed 2-yr period to within an accuracy of 10% when the sections are averaged in either an Eulerian (geographic) or stream coordinates manner. However, even with 10 sections during a 2-yr period the details of the mean velocity and temperature structures obtained can be quite different than the "true" 2-yr mean structure, regardless of whether the sections are averaged in either Eulerian or stream coordinates. It is estimated that at least 20 independent sections would be required during a 2-yr period in order to determine the baroclinic velocity structure to within an accuracy of 10%, irrespective of whether they are averaged in Eulerian or stream coordinates. Implications for future sampling strategies and for inverse modeling analyses are discussed.

Melo, N., T.N. Lee, E. Johns, R.H. Smith, P.B. Ortner, and D. Smith. Recent measurements of salinity, flow, and sea level variability in western basins of Florida Bay-Rabbit and Twin Key Basins. Proceedings, 2005 Florida Bay and Adjacent Marine Systems Science Conference, Duck Key, FL, December 11-14, 2005. University of Florida, 141-142 (2005).

No abstract.

Mestas-Nunez, A.M., C. Zhang, and D.B. Enfield. Uncertainties in estimating moisture fluxes over the Intra-Americas Sea. Journal of Hydrometeorology, 6(5):696-709 (2005).

This study estimates discrepancies in moisture flux divergence in the Intra-Americas Sea (IAS; including the Gulf of Mexico and the Caribbean Sea) calculated using sounding observations, the NCEP Eta high-resolution regional analysis, and the NCEP-NCAR coarse-resolution global reanalysis. The main purpose of this exercise is to quantify the uncertainties in the global reanalysis when it is used to calculate annual and interannual variability of moisture flux divergence in the region. An accurate estimate of moisture flux divergence is crucial to evaluate whether the IAS serves as a water vapor source for rainfall over the adjacent land. Using the three datasets, the uncertainties of calculated moisture flux divergence due to the design of the boundary of the area, mathematical algorithms, and spatial and temporal resolutions are quantified. The results show that the large seasonal and interannual variability in moisture flux divergence estimated using the NCEP-NCAR reanalysis is not compromised by these uncertainties. Therefore, NCEP-NCAR reanalysis, with its global coverage and long-term record, can be used to provide the best estimate of short climate variability of moisture flux divergence available to date. Further comparisons are made of the moisture flux divergence based on the NCEP-NCAR reanalysis with previous estimates using single-year sounding observations, as well as with multiyear estimates based on global datasets of surface evaporation and precipitation. It is shown that the previous estimates using single-year sounding observations bear large uncertainties because of interannual variability. Large uncertainties also exist in datasets of surface global evaporation and precipitation.

Michaels, P.J., P.C. Knappenberger, and C.W. Landsea. Comments on "Impacts of CO₂-induced warming on simulated hurricane intensity and precipitation: Sensitivity to the choice of climate model and convective scheme." Journal of Climate, 18(23):5179-5182 (2005).

In a simulation of enhanced tropical cyclones in a warmer world, Knutson and Tuleya make several assumptions that are not borne out in the real world. They include an unrealistically large carbon dioxide growth rate, an overly strong relationship between sea surface temperature and hurricane intensity, and the use of a mesoscale model that has shown little to no useful skill in predicting current-day hurricane intensity. After accounting for these inaccuracies, a detectable increase in Atlantic hurricane intensity in response to growing atmospheric greenhouse gas levels during this century becomes unlikely.

Mooers, C.N.K., C.S. Meinen, M.O. Baringer, I. Bang, R. Rhodes, C.N. Barron, and F. Bub. Cross validating ocean prediction and monitoring systems. EOS, Transactions, American Geophysical Union, 86(29):269, 272-273 (2005).

With the ongoing development of ocean circulation models and real-time observing systems, routine estimation of the synoptic state of the ocean is becoming feasible for practical and scientific purposes. The models can assist in ocean monitoring and regional dynamics studies, but only after they have been validated. For the first time, beginning 1 November 2004, independent ocean model estimates of the Florida Current (FC) volume transport are available, in real time, for cross validation with observed transport variations forced by cold front passages, tropical cyclones, and other weather systems. The FC flows poleward through the Straits of Florida and ultimately becomes the Gulf Stream. The FC originates from both the large-scale, wind-driven circulation of the North Atlantic subtropical gyre and the trans-equatorial Atlantic thermohaline overturning circulation (i.e., the "global conveyor belt"). The FC is constrained by Florida to the north and/or west and by Cuba and the Bahamas to the south and east, respectively (Figure 1).

Morrison, I., S. Businger, F.D. Marks, P.P. Dodge, and J.A. Businger. An observational case for the prevalence of roll vortices in the hurricane boundary layer. Journal of the Atmospheric Sciences, 62(8):2662-2673 (2005).

Doppler velocity data from the WSR-88D radar during four hurricane landfalls are analyzed to investigate the presence of organized vortices in the hurricane boundary layer (HBL). The wavelength, depth, magnitude, and track of velocity anomalies were compiled through analysis of Doppler velocity data. The analysis reveals alternating bands of enhanced and reduced azimuthal winds that are closely aligned with the mean wind direction. Resulting statistics provide compelling evidence for the presence of organized secondary circulations or boundary layer rolls across significant areas during four hurricane landfalls. The results confirm previous observations of the presence of rolls in the HBL. A potential limitation of the study presented here is the resolution of the WSR-88D data. In particular, analysis of higher resolution data (e.g., from the Doppler on Wheels) is needed to confirm that data aliasing has not unduly impacted the statistics reported here. Momentum fluxes associated with the secondary circulations are estimated using the covariance between the horizontal and vertical components of the wind fluctuations in rolls, with resulting fluxes 2-3 times greater than estimated by parameterizations in numerical weather prediction models. The observational analysis presented here, showing a prevalence of roll vortices in the HBL, has significant implications for the vertical transport of energy in hurricanes, for the character of wind damage, and for improvements in numerical simulations of hurricanes.

Nuissier, O., R.F. Rogers, and F. Roux. A numerical simulation of Hurricane Bret on 22-23 August 1999 initialized with airborne Doppler radar and dropsonde data. Quarterly Journal of the Royal Meteorological Society, 131(605):155-194 (2005).

This study concerns the simulation of Hurricane Bret on 22-23 August 1999 with the MesoNH non-hydrostatic, two-way interactive, quadruply nested grid mesoscale model. A 30-h integration, from 0000 UTC 22 August to 0600 23 August, covers the period of maximum intensity over the Gulf of Mexico and landfall over Texas. Special attention is paid to the initial conditions from which the model is integrated. A balanced vortex, derived from airborne Doppler radar data, is used to replace the ill-defined cyclone in the large-scale analysis. In addition, the analyzed humidity field over the Gulf of Mexico is modified in accordance with specific dropsonde observations. A comparison between the simulated storm track and intensity for three different numerical experiments shows that the inclusion of the radar-derived vortex and high spatial resolution are necessary to obtain a realistic simulation. After an initial period of adjustment, the simulation with the inserted radar-derived vortex and high resolution produces a storm only 10 hPa weaker than the observation after 24 h, compared to the control run that was nearly 50 hPa weaker at the same time. The characteristics of this simulated storm at mature stage are then presented, with particular emphasis placed on the processes that modulate the intensity of the inner core region.

Olsen, A., R. Wanninkhof, J.A. Trinanes, and T. Johannessen. The effect of wind speed products and wind speed-gas exchange relationships on interannual variability of the air-sea CO₂ gas transfer velocity. Tellus B, 57(2):95-106 (2005).

The lack of a firm relationship between wind speed (U₁₀) and gas transfer velocity (k) is considered to be one of the factors that hinders accurate quantification of interannual variations of ocean-atmosphere CO₂ fluxes. In this paper, the interannual variations of k of using four different k-U₁₀ parameterizations are examined using wind speed data from the NCEP/NCAR reanalysis project. The extent to which interannual variations are faithfully reproduced in the NCEP/NCAR data is also investigated. This is carried out through comparison with QuikSCAT data. Compared with 4 years of QuikSCAT data, NCEP/NCAR data reproduce interannual k variations, although the absolute magnitude of k is underestimated. Interannual k variation shows great sensitivity to selection of k-U₁₀ parameterization, and in the Westerlies it changes by a factor of three depending on k-U₁₀ parameterization. Use of monthly mean winds speeds leads to overestimation of interannual k variations compared with k variations computed using 6-hourly wind speeds and the appropriate k-U₁₀ parameterization. Even though the effect of changing k-U₁₀ parameterization is large enough to be an issue that needs to be considered when computing interannual air-sea CO₂ flux variations through combining estimates of k with data for the air-sea CO₂ gradient, it is not sufficient to bridge the gap between such estimates and estimates based on analyses of atmospheric oxygen, CO₂, and delta¹³C data. Finally, it is shown that the ambiguity in the relationship between wind speed and k introduces an uncertainty in interannual flux variations comparable to a bias of interannual DELTApCO₂ variations of at most �5 µatm.

Palmer, D.R. Acoustical scattering from constituents of an ocean plume located near a boundary surface. IEEE Transactions on Geoscience and Remote Sensing, 43(4):770-777 (2005).

A formalism exists for estimating the intensity recorded by a sonar system due to scattering from a ocean plume of suspended, nonspherical scatterers in the Rayleigh region. In this paper we extend this framework to include the possibility that the plume is located near a planar ocean boundary. Using the theory of isoperimetric inequalities, bounds are obtained for the magnitude of the scattering amplitude that are independent of shape and the aspect of the individual plume constituents. Two examples are considered to illustrate the application of the analysis; scattering from the particulates that comprise black smoker hydrothermal plumes and scattering from bubbles.

Palmer, D.R., and P.A. Rona. Acoustical imaging of deep ocean hydrothermal flows. In Sounds in the Sea: From Ocean Acoustics to Acoustical Oceanography, H. Medwin (ed.). Cambridge University Press, 551-563 (2005).

No abstract.

Peltola, E., R. Wanninkhof, R. Feely, R. Castle, D. Greeley, J.-Z. Zhang, F. Millero, N. Gruber, J. Bullister, and T. Graham. Inorganic carbon, nutrient, and oxygen data from the R/V Ronald H. Brown Repeat Hydrography Cruise in the Atlantic Ocean: CLIVAR CO₂ section A16N_2003a (4 June-11 August 2003), A. Kozyr (ed.). Oak Ridge National Laboratory/Carbon Dioxide Information Analysis Center, ORNL/CDIAC-149, NDP-085, 36 pp. (2005).

This report presents methods and analytical and quality control procedures for nutrient, oxygen, and inorganic carbon system parameters performed during the A16N_2003a cruise, which took place from June 4 to August 11, 2003 aboard NOAA Ship R/V Ronald H. Brown under auspices of the National Oceanic and Atmospheric Administration (NOAA). The first hydrographic leg (June 19-July 10) was from Reykjavik, Iceland, to Funchal, Madeira, Portugal along the 20°W meridian, and the second leg (July 15-August 11) continued operations from Funchal, Portugal to Natal, Brazil, on a track southward and ending at 6°S, 25°W. The research was the first in a decadal series of repeat hydrography sections jointly funded by NOAA and the National Science Foundation (NSF) as part of the CLIVAR/CO₂/hydrography/tracer program. Samples were taken from up to 34 depths at 150 stations. The data presented in this report includes the analyses of water samples for total inorganic carbon (TCO₂), fugacity of CO₂ (fCO₂), total alkalinity (TALK), pH, nitrate (NO₃), nitrite (NO₂), phosphate (PO₄), silicate (SiO₄), and dissolved oxygen (O₂). The R/V Ronald H. Brown A16N_2003a data set is available free of charge as a numeric data package (NDP) from the Carbon Dioxide Information Analysis Center (CDIAC). The NDP consists of the oceanographic data files and this printed documentation, which describes the procedures and methods used to obtain the data.

Peng, T.-H. Anthropogenic CO₂ in the ocean. Scientia Marina, 69(suppl. 1):85-96 (2005).

The focus of this review article is on the anthropogenic CO₂ taken up by the ocean. There are several methods of identifying the anthropogenic CO₂ signal and quantifying its inventory in the ocean. The DELTA-C* method is most frequently used to estimate the global distribution of anthropogenic CO₂ in the ocean. Results based on analysis of the data set obtained from the comprehensive surveys of inorganic carbon distribution in the world oceans in the 1990s are given. These surveys were jointly conducted during the World Ocean Circulation Experiment (WOCE) and the Joint Global Ocean Flux Study (JGOFS). This data set consists of 9,618 hydrographic stations from a total of 95 cruises, which represents the most accurate and comprehensive view of the distribution of inorganic carbon in the global ocean available today. The increase of anthropogenic CO₂ in the ocean during the past few decades is also evaluated using direct comparison of results from repeat surveys and using the statistical method of Multi-parameter Linear Regression (MLR). The impact of increasing oceanic anthropogenic CO₂ on the calcium carbonate system in the ocean is reviewed briefly as well. Extensive studies of CaCO₃ dissolution as a result of increasing anthropogenic CO₂ in the ocean have revealed several distinct oceanic regions where the CaCO₃ undersaturation zone has expanded.

Piekle, R.A., Jr., C.W. Landsea, M. Mayfield, J. Laver, and R. Pasch. Hurricanes and global warming. Bulletin of the American Meteorological Society, 86(11):1571-1575 (2005).

This paper reviews recent research on tropical cyclones and climate change from the perspective of event riskthe physical behavior of storms; vulnerabilitythe characteristics of a system that creates the potential for impacts, but are independent of event risk; and also outcome riskthe integration of considerations of vulnerability with event risk to characterize an event that causes losses. The paper concludes that with no trend identified in various metrics of hurricane damage over the 20th century, it is exceedingly unlikely that scientists will identify large changes in historical storm behavior that have significant societal implications, though scientists may identify discernible changes in storm behavior. Looking to the future, until scientists conclude (a) that there will be changes to storms that are significantly larger than observed in the past, (b) that such changes are correlated to measures of societal impact, and (c) that the effects of such changes are significant in the context of inexorable growth in population and property at risk, then it is reasonable to conclude that the significance of any connection of human-caused climate change to hurricane impacts necessarily has been and will continue to be exceedingly small.

Powell, M.D., G.A. Soukup, S. Cocke, S. Gulati, N. Morisseau-Leroy, S. Hamid, N.M. Dorst, and L. Axe. State of Florida hurricane loss projection model: Atmospheric science component. Journal of Wind Engineering and Industrial Aerodynamics, 93(8):651-674 (2005).

The State of Florida has developed an open, public model for the purpose of probabilistic assessment of risk to insured residential property associated with wind damage from hurricanes. The model comprises atmospheric science, engineering, and financial/actuarial components and is planned for submission to the Florida Commission on Hurricane Loss Projection Methodology. The atmospheric component includes modeling the track and intensity life cycle of each simulated hurricane within the Florida threat area. When a model storm approaches within a damage threshold distance of a Florida zip code location, the wind field is computed by a slab model of the hurricane boundary layer coupled with a surface layer model based on the results of recent GPS sonde research. A time series of open terrain surface winds is then computed for each zip code in the threatened area. Depending on wind direction, an effective roughness length is assigned to each zip code based on the upstream fetch roughness as determined from remotely sensed land cover/land use products. Based on historical hurricane statistics, thousands of storms are simulated allowing determination of the wind risk for all residential zip code locations in Florida. The wind risk information is then provided to the engineering and loss models to assess damage and average annual loss, respectively.

Proni, J.R., V. Fox-Norse, S.J. Stamates, and J.F. Craynock. Innovative applications of ocean acoustics and other technologies for marine water quality monitoring and assessment: Effluent plume studies of the MWRA Outfall. Proceedings, 14th Biennial Coastal Zone Conference, New Orleans, LA, July 17-21, 2005. NOAA Coastal Services Center, CD-ROM, 7 pp. (2005).

No abstract.

Rudnick, D.T., P.B. Ortner, J.A. Browder, and S.M. Davis. A conceptual ecological model of Florida Bay. Wetlands, 25(4):870-883 (2005).

Florida Bay is a large and shallow estuary that is linked to the Everglades watershed and is a target of the Greater Everglades ecosystem restoration effort. The conceptual ecological model presented here is a qualitative and minimal depiction of those ecosystem components and linkages that are considered essential for understanding historic changes in the Bay ecosystem, the role of human activities as drivers of these changes, and how restoration efforts are likely to affect the ecosystem in the future. The conceptual model serves as a guide for monitoring and research within an adaptive management framework. Historic changes in Florida Bay that are of primary concern are the occurrence of seagrass mass mortality and subsequent phytoplankton blooms in the 1980s and 1990s. These changes are hypothesized to have been caused by long-term changes in the salinity regime of the Bay that were driven by water management. However, historic ecological changes also may have been influenced by other human activities, including occlusion of passes between the Florida Keys and increased nutrient loading. The key to Florida Bay restoration is hypothesized to be seagrass community restoration. This community is the central ecosystem element, providing habitat for upper trophic level species and strongly influencing productivity patterns, sediment resuspension, light penetration, nutrient availability, and phytoplankton dynamics. An expectation of Everglades restoration is that changing patterns of freshwater flow toward more natural patterns will drive Florida Bay's structure and function toward its pre-drainage condition. However, considerable uncertainty exists regarding the indirect effects of changing freshwater flow, particularly with regard to the potential for changing the export of dissolved organic matter from the Everglades and the fate and effects of this nutrient source. Adaptive management of Florida Bay, as an integral part of Everglades restoration, requires an integrated program of monitoring, research to decrease uncertainties, and development of quantitative models (especially hydrodynamic and water quality) to synthesize data, develop and test hypotheses, and improve predictive capabilities. Understanding and quantitatively predicting changes in the nature of watershed-estuarine linkages is the highest priority scientific need for Florida Bay restoration.

Sabine, C.L., R.M. Key, A. Kozyr, R.A. Feely, R. Wanninkhof, F.J. Millero, T.-H. Peng, J.L. Bullister, and K. Lee. Global ocean data analysis project (GLODAP): Results and data. Oak Ridge National Laboratory/Carbon Dioxide Information Analysis Center, ORNL/CDIAC-145, NDP-083, 110 pp. (2005).

During the 1990s, ocean sampling expeditions were carried out as part of the World Ocean Circulation Experiment, the Joint Global Ocean Flux Study, and the Ocean Atmosphere Carbon Exchange Study. Most of the cruises included various inorganic carbon species among the suite of routinely measured parameters. Both during and after the field work, a group of U.S. scientists collaborated to synthesize the data into easily usable and readily available products. This collaboration is known as the Global Ocean Data Analysis Project (GLODAP). Both measured results and calculated quantities were merged into common-format data sets, segregated by ocean. The carbon data were subjected to rigorous secondary quality control procedures, beyond those typically performed on individual cruise data, to eliminate systematic biases in the basin-scale compilations. For comparison purposes, each ocean data set included results from a small number of high-quality historical cruises. The calibrated 1990s data were used to estimate anthropogenic CO₂, potential alkalinity, chlorofluorocarbon (CFC) water mass ages, CFC partial pressure, bomb-produced radiocarbon, and natural radiocarbon. The calibrated-merged data were used to produce objectively gridded global property maps designed to match existing climatologies for temperature, salinity, oxygen, and nutrients. Both the data sets and the gridded products are available from the Carbon Dioxide Information Analysis Center (CDIAC). Here we summarize important details of the data assembly, calibration, calculations, and mapping. The synthesis was carried out one ocean at a time, progressing from the Indian to the Pacific and ending with the Atlantic. The entire synthesis required about five years. During that period, new methods were developed and old ones modified. At the same time, the data set itself changed and expanded. Many of the GLODAP results are already published. Rather than repeat what is published, we concentrate here on summarizing important details of the data assembly and mapping. In particular, we focus on the procedural differences that evolved as the individual basin data sets were compiled and developments in the data set that have not been covered in the individual publications. Some of the GLODAP publications are attached as appendices. The GLODAP data set described here (Gv1.1) is available free of charge as a numeric data package (NDP-83) from CDIAC. The data, and any subsequent updates, are also available through the GLODAP web site (http://cdiac.ornl.gov/oceans/glodap/Glodap_home.htm). The GLODAP bottle data files are available in flat ASCII file data format, in Ocean Data View (ODV) format, and through the CDIAC live access server (LAS); the gridded data files are available in flat ASCII and NetCDF data file formats and through CDIAC LAS.

Schmid, C. Impact of combining temperature profiles from different instruments on an analysis of mixed layer properties. Journal of Oceanic and Atmospheric Technology, 22(10):1571-1587 (2005).

For a joint analysis of temperature profiles from floats, expendable bathythermographs (XBTs), and other instruments (e.g., thermistor chains), the consistency of the profiles from the different sources needs to be ensured to avoid results with systematic errors. In this study, profiles from the different instrument types are compared after they passed through a series of quality control tests. The different methods for quality control are presented. After ensuring that only high-quality profiles remain in the dataset, a statistical analysis of the temperature differences between adjacent profiles (in space and time) is performed. Potential regional differences, as well as possible differences between the various float types, are addressed. Finally, the impact of combining the profiles from floats with those from other instruments on gridded fields of the mixed layer temperature, thickness, and heat budget is discussed. It is found that the joint analysis yields more reliable results for the gridded fields and the heat storage rate. A large part of this improvement is a result of the reduced seasonal bias.

Schmid, C., B. Bourles, and Y. Gouriou. Impact of the equatorial deep jets on estimates of zonal transport in the Atlantic. Deep-Sea Research, Part II, 52(3-4):409-428 (2005).

The structure and variability of the zonal equatorial flow in the Atlantic is studied on the basis of velocity profiles obtained with lowered Acoustic Doppler Current Profilers during multiple surveys. The vertical extent of the zonal currents is found to vary considerably. It can be as small as 100 m or as large as 1000 m. In the Atlantic, vertical scales of 400-600 m have been associated with the equatorial deep jets (they are also frequently called deep jets or stacked jets). Typical amplitudes of the zonal velocity are about 20 cm s^-1. An analysis of quasi-synoptic surveys indicates that the zonal extent of most jets is likely to be at least 27°. They can rise or deepen from west to east, although the deepening was observed more often and is often more pronounced. The west to east deepening can be as large as 320 m/10°. Basin-wide mean depth changes of the jets are mostly on the order of 50 m/10°, and the largest depth changes are typically observed between 35° and 23°W. The existence of these changes indicates that vertically propagating, equatorially trapped, waves might be one cause for the jet structure. However, the dependence of the slope on the longitude indicates that other processes must be involved as well. The typical vertical extent of the jets is small enough to result in several direction changes of the zonal flow in the Antarctic Intermediate Water (AAIW) and the North Atlantic Deep Water (NADW) layer. From transport estimates for 14 meridional sections it is found that the transport for the westward component of the flow within the AAIW layer (500-1000 m) can be as large as -24 Sv (1Sv = 10⁶ m³ s^-1) within 1° of the equator. For the eastward component of the flow in the AAIW layer the transport can be as large as 8 Sv. Adding the transport components for each section results in a range of total AAIW transports from -24 to 7 Sv. This suggest that the annual mean transport of AAIW is westward. The only months with eastward total transports are June and July. This is consistent with earlier Lagrangian and some other observations that indicated that the AAIW flow along the equator is governed by an annual cycle. In the NADW layer (1200-3900 m) the transport for the westward (eastward) flow can be as large as -25 Sv (23 Sv) within 1° of the equator. This results in a range of total NADW transports from -10 to 18 Sv. The variations of the total transports of AAIW and NADW are anti-correlated, with a correlation coefficient of -0.86. Since only eight sections reached deep enough to allow transport estimates in the NADW layer, it is more difficult to come to a conclusion about the mean transport in this layer than for the transport in the AAIW layer (for the latter layer 14 sections were available). Nevertheless, the obtained estimates suggest that the total NADW transport may be eastward.

Shaji, C., C. Wang, G.R. Halliwell, and A. Wallcraft. Simulation of tropical Pacific and Atlantic Oceans using a Hybrid Coordinate Ocean Model (HYCOM). Ocean Modelling, 9(3):253-282 (2005).

The climatological annual cycle of the tropical Pacific and Atlantic Oceans is simulated using the HYbrid Coordinate Ocean Model (HYCOM) configured in a non-uniform horizontal grid spanning 30°S-65.5°N and 102°E-15°E. The model is initialized with climatological summer temperature and salinity and is forced by climatological atmospheric fields derived from the COADS and ECMWF ERA-15 reanalysis. The model is spun up for 20 years to reach a reasonable steady state in the primary region of interest from 20°S to 20°N, and year 20 is analyzed. The COADS simulation is primarily analyzed because it is slightly better in more respects than the ECMWF simulation, particularly in the representation of upper-ocean thermal structure. The model generally reproduces the seasonal variability of major circulation features in both oceans reasonably well when compared to climatologies derived from several observational datasets (surface drifters, TAO mooring array, COADS, Levitus, Pathfinder SST), and when compared to other model simulations. Model evaluation is complicated by the fact that the different climatologies, including the atmospheric reanalysis climatologies that drive the model, are averaged over different time intervals. In the tropics, the model thermocline reproduces the observed zonal slopes and meridional ridges/troughs in the thermocline. The simulated Equatorial Undercurrent compares favorably to observations, but is slightly deeper than observed. The model overestimates temperature in the Pacific warm pool regions, both west and east, by more than 1°C when compared to all observed climatologies. The model also tends to overestimate temperature in the eastern equatorial cold tongues in both the Atlantic and Pacific, with this overestimate being confined to a very small region of the far eastern Pacific during winter. This overestimate varies substantially depending on which observed climatology is used for the comparison, so model limitations are only partly responsible for the simulated-observed temperature differences in the cold tongues.

Shoosmith, D.R., M.O. Baringer, and W.E. Johns. A continuous record of Florida Current temperature transport at 27°N. Geophysical Research Letters, 32(23):L23603, doi:10.1029/2005GL024075 (2005).

As part of a newly funded international program to monitor ocean heat transport at mid-latitudes in the North Atlantic, a continuous estimate of the temperature transport of the Florida Current is required. Since 1982, volume transports have been inferred from voltage measurements monitored by submarine telephone cables across the Straits of Florida. Electromagnetic induction theory suggests that the cable voltage should actually give a more direct measure of conductivity transport than pure volume transport. Due to the strong dependence of conductivity on temperature, this would, in theory, result in a direct and continuous estimate of the Florida Current temperature transport. This hypothesis is investigated using data from a large number of temperature and velocity sections (58) across the Florida Current at the cable location, leading to a new calibration of the voltage signal for the temperature transport of the Florida Current, crucial for trans-basin heat flux estimates.

Smith, R.H., E. Johns, P.B. Ortner, T.N. Lee, C.R. Kelble, and N. Melo. Satellite-tracked surface drifter trajectories reveal the spatial and temporal current variability of south Florida. Proceedings, 2005 Florida Bay and Adjacent Marine Systems Science Conference, Duck Key, FL, December 11-14, 2005. University of Florida, 148-149 (2005).

No abstract.

Smith, R.H., E.M. Johns, S.R. Cummings, P.B. Ortner, C.R. Kelble, N. Melo, and T.N. Lee. The influence of the 2005 hurricane season on water quality in Florida Bay and surrounding coastal waters. Proceedings, 2005 Florida Bay and Adjacent Marine Systems Science Conference, Duck Key, FL, December 11-14, 2005. University of Florida, 146-147 (2005).

No abstract.

Soneira, G. AMVER/SEAS 2000 update, June 2005. Mariners Weather Log, 49(2):8-9 (2005).

No abstract.

Susskind, J., and R. Atlas. Atmospheric soundings from AIRS/AMSU in partial cloud cover. In Algorithms and Technologies for Multispectral, Hyperspectral, and Ultraspectral Imagery XI, S.S. Shen and P.E. Lewis (eds.). Proceedings, SPIE, 5806:587-598 (2005).

Simultaneous use of AIRS/AMSU-A observations allow for the determination of accurate atmospheric soundings under partial cloud cover conditions. The methodology involves the determination of the radiances AIRS would have seen if the AIRS fields of view were clear, called clear column radiances, and use of these radiances to infer the atmospheric and surface conditions giving rise to these clear column radiances. Susskind et al. demonstrate via simulation that accurate temperature soundings and clear column radiances can be derived from AIRS/AMSU-A observations in cases of up to 80% partial cloud cover, with only a small degradation in accuracy compared to that obtained in clear scenes. Susskind and Atlas show that these findings hold for real AIRS/AMSU-A soundings as well. For data assimilation purposes, this small degradation in accuracy is more than offset by a significant increase in spatial coverage (roughly 50% of global cases were accepted, compared to 3.6% of the global cases being diagnosed as clear), and assimilation of AIRS temperature soundings in partially cloudy conditions resulted in a larger improvement in forecast skill than when AIRS soundings were assimilated only under clear conditions. Alternatively, derived AIRS clear column radiances under partial cloud cover could also be used for data assimilation purposes. Further improvements in AIRS sounding methodology have been made since the results shown in Susskind and Atlas. A new version of the AIRS/AMSU-A retrieval algorithm, Version 4.0, was delivered to the Goddard DAAC in February 2005 for production of AIRS derived products, including clear column radiances. The major improvement in the Version 4.0 retrieval algorithm is with regard to a more flexible, parameter dependent, quality control. Results are shown of the accuracy and spatial distribution of temperature-moisture profiles and clear column radiances derived from AIRS/AMSU-A as a function of fractional cloud cover using the Version 4.0 algorithm. Use of the Version 4.0 AIRS temperature profiles increased the positive forecast impact arising from AIRS retrievals relative to what was shown in Susskind and Atlas.

Velden, C., J. Daniels, D. Stettner, D. Santek, J. Key, J.P. Dunion, K. Holmlund, G. Dengel, W. Bresky, and P. Menzel. Recent innovations in deriving tropospheric winds from meteorological satellites. Bulletin of the American Meteorological Society, 86(2):205-223 (2005).

The evolving constellation of environmental/meteorological satellites and their associated sensor technology is rapidly advancing. This is providing opportunities for creatively improving satellite-derived products used in weather analysis and forecasting. For example, the retrieval methods for deriving atmospheric motion vectors (AMVs) from satellites have been expanding and evolving since the early 1970s. Contemporary AMV processing methods are continuously being updated and advanced through the exploitation of new sensor technologies and innovative new approaches. It is incumbent upon the research community working in AMV extraction techniques to ensure that the quality of the current operational products meets or exceeds the needs of the user community. In particular, the advances in data assimilation and numerical weather prediction in recent years have placed an increasing demand on data quality. To keep pace with these demands, innovative research toward improving methods of deriving winds from satellites has been a focus of the World Meteorological Organization and Coordination Group for Meteorological Satellites (CGMS) cosponsored International Winds Workshops (IWWs). The IWWs are held every tw years, and bring together AMV researchers from around the world to present new ideas on AMV extraction techniques, interpretation, and applications. The NWP community is always well represented at these workshops, which provide an important exchange of information on the latest in data assimilation issues. This article draws from recent IWWs, and describes several new advances in satellite-produced wind technologies, derivation methodologies, and products. Examples include AMVs derived from Geostationary Operational Environmental Satellite (GOES) rapid scans and the short-wave IR channel, AMVs over the polar regions from the Moderate Resolution Imaging Spectroradiometer (MODIS), improved AMV products from the new Meteosat Second Generation satellite, and new processing approaches for deriving AMVs. The article also provides a glimpse into the pending opportunities that will be afforded with emerging/anticipated new sensor technologies.

Wang, C. Subthermocline tropical cells and equatorial subsurface countercurrents. Deep-Sea Research, Part I, 52(1):123-135 (2005).

Eastward subsurface countercurrents (SSCCs) are observed in both the Pacific and Atlantic Oceans on either side of the equator, and are associated with a poleward shoaling of subthermocline isotherms at the poleward flanks of the equatorial 13°C thermostad. Observations suggest that eastward SSCCs correspond to a meridional circulation of subthermocline tropical cells (STTCs). The STTCs are below and weaker than the tropical cells, being characterized by an equatorward flow in the thermocline, an equatorial downwelling, a poleward flow in the subthermocline, and an upwelling about 3-4° from the equator. The essential dynamics of the SSCCs can be explained in terms of the conservation of absolute vorticity in the poleward flow of the lower branch of the STTCs. As a parcel within the subthermocline moves poleward, its gain of planetary vorticity is compensated by a loss of relative vorticity, resulting in the eastward SSCCs. By applying the conservation of potential vorticity, the paper also shows that the poleward shoaling of subthermocline isotherms at the poleward flanks of the thermostad can contribute to the eastward SSCCs.

Wang, D., C. Wang, X. Yang, and J. Lu. Winter northern hemisphere surface air temperature variability associated with the Arctic Oscillation and North Atlantic Oscillation. Geophysical Research Letters, 32(16):L16706, doi:10.1029/2005GL022952 (2005).

The interannual variability of winter surface air temperature (SAT) in the Northern Hemisphere (NH) associated with the Arctic Oscillation (AO) and the North Atlantic Oscillation (NAO) is studied. The AO and the NAO show different impacts on winter NH SAT variations. The AO affects the SAT over the Euro-Asian and African continents, whereas the NAO is more regional with the major effect on the SAT in the western North Africa. This discrepancy can be reflected in other atmospheric variables such as sea level pressure and geopotential height fields as well. The analyses in this paper also suggest that the AO-related signal can penetrate deeply into the stratosphere while the NAO one is largely a tropospheric phenomenon.

Wanninkhof, R., R.A. Feely, N.R. Bates, F.J. Millero, T. Takahashi, and S.K. Cook. Document ocean carbon sources and sinks, pp. 254-262. In Annual Report on the State of the Ocean and Ocean Observing System for Climate (FY-2004), D.M. Stanitski (ed.). NOAA Office of Climate Observation, Silver Spring, MD, 422 pp. (2005).

No abstract.

Wanninkhof, R.H., K.F. Sullivan, W.P. Dammann, J.R. Proni, F. Bloetscher, A.V. Soloviev, and T.P. Carsey. Farfield tracing of a point source discharge plume in the coastal ocean using sulfur hexafluoride. Environmental Science and Technology, 39(22):8883-8890 (2005).

Pathways and dilution of a point source ocean discharge in the farfield (approximately equal to 10-66 km) were measured using the deliberate tracer sulfur hexafluoride (SF₆). The injection of SF₆ was performed by bubbling the gas over a period of 6 days into an ocean outfall pipe discharging into the southeast Florida coastal ocean. The surface SF₆ concentrations show that the discharged water flowed northward parallel to the coast with a broadening of the width of the plume to about 3 km at the farthest point sampled, 66 km from the outfall. The discharge was fully mixed throughout the water column within 13 km of the outfall terminus. In the first 20 km from the outfall, SF₆ surface concentrations were highly variable, while beyond this the SF₆ concentrations decreased monotonically going northward. The currents were measured during the study with a bottom-mounted acoustic Doppler current profiler (ADCP) located 5.5 km from the outfall. Velocities were variable in magnitude and direction but showed a net northward flow during the 6-day study. Maximum concentrations decreased by about 200-fold per kilometer from the outfall to the northern end of the study area. The study shows that SF₆ is an effective method to trace point source releases far from their origin.

Wanninkhof, R.H., S.C. Doney, E. Peltola, R.D. Castle, F.J. Millero, J.L. Bullister, D.A. Hansell, M.J. Warner, C. Langdon, G.C. Johnson, and C.W. Mordy. Carbon dioxide, hydrographic, and chemical data obtained during the R/V Ronald H. Brown Repeat Hydrography Cruise in the Atlantic Ocean: CLIVAR CO₂ section A16S_2005 (11 January-24 February 2005), A. Kozyr (ed.). Oak Ridge National Laboratory/Carbon Dioxide Information Analysis Center, Oak Ridge, TN, ORNL/CDIAC-151, NDP-087, 38 pp. (2005).

This report presents methods, and analytical and quality control procedures for salinity, oxygen, nutrient, inorganic carbon, organic carbon, chlorofluorocarbon (CFC), and bomb ¹⁴C system parameters performed during the A16S_2005 cruise, which took place from January 11 to February 24, 2005, aboard research vessel (R/V) Ronald H. Brown under the auspices of the National Oceanic and Atmospheric Administration (NOAA). The R/V Ronald H. Brown departed Punta Arenas, Chile, on January 11, 2005, and ended its cruise in Fortaleza, Brazil, on February 24, 2005. The research conducted was one of a series of repeat hydrography sections jointly funded by NOAA and the National Science Foundation as part of the CLIVAR/CO₂/Repeat Hydrography/Tracer Program. Samples were taken from 36 depths at 121 stations. The data presented in this report include the analyses of water samples for total inorganic carbon (TCO₂), fugacity of CO₂ (fCO₂), total alkalinity (TALK), pH, dissolved organic carbon (DOC), CFC, ¹⁴C, hydrographic, and other chemical measurements. The R/V Ronald H. Brown A16S_2005 data set is available free of charge as a numeric data package (NDP) from the Carbon Dioxide Information Analysis Center (CDIAC). The NDP consists of the oceanographic data files and this printed documentation, which describes the procedures and methods used to obtain the data.

Wu, C.-C., P.-H. Lin, and S.D. Aberson. Typhoon surveillance in northwestern Pacific. Vaisala News, 167:24-25 (2005).

No abstract.

Wu, C.-C., P.-H. Lin, S.D. Aberson, T.-C. Yeh, W.-P. Huang, K.-H. Chou, J.-S. Hong, G.-C. Lu, C.-T. Fong, K.-C. Hsu, I.-I. Lin, P.-L. Lin, and C.-H. Liu. Dropsonde observations for typhoon surveillance near the Taiwan region (DOTSTAR): An overview. Bulletin of the American Meteorological Society, 86(6):787-790 (2005).

No abstract. **2004**

Aberson, S.D. The G-IV surveillance era, targeting, and ensemble forecasts (1997-present). Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 236-237 (2004).

No abstract.

Aberson, S.D., M.L. Black, M.T. Montgomery, and M. Bell. A record wind measurement in Hurricane Isabel: Direct evidence of an eyewall mesocyclone? Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 168-169 (2004).

No abstract.

Baringer, M.O., E. Johns, C.S. Meinen, S.L. Garzoli, and A. Flosadottir. Western boundary time series in the Atlantic Ocean, pp. 77-89. In Annual Report on the State of the Ocean and the Ocean Observing System for Climate, D.M. Stanitski (ed.). NOAA Office of Climate Observation, Silver Spring, MD, 307 pp. (2004).

No abstract.

Bell, M.M., M.T. Montgomery, M.L. Black, and S.D. Aberson. Observed vortex and thermodynamic structure of Hurricane Isabel at maximum intensity. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 196-197 (2004).

No abstract.

Bell, G.D., S.B. Goldenberg, C.W. Landsea, E. Blake, R. Pasch, M. Chelliah, and K. Mo. Atlantic hurricane season. In State of the Climate in 2003, D.H. Levinson and A.M. Waple (eds). Bulletin of the American Meteorological Society, 85(6):S20-S24 (2004).

No abstract.

Black, M.L., F.D. Marks, R.F. Rogers, L.K. Shay, B.A. Albrecht, and H.E. Willoughby. The mean structure of vertical velocities and radar reflectivities in the hurricane eyewall as they relate to environmental wind shear. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 94-95 (2004).

No abstract.

Black, M.L., J.P. Dunion, J.P. Kossin, W.H. Schubert, C.S. Velden, P.G. Black, R. Zehr, and S.D. Aberson. Mesovortices in Hurricane Isabel (2003): A comparison of satellite, radar, and photographic observations. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 128-129 (2004).

No abstract.

Black, P.G. An overview of CBLAST flights into Hurricanes Fabian and Isabel (2003). Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 1-2 (2004).

No abstract.

Black, P.G., E.W. Uhlhorn, J.F. Gamache, W.D. Ramstrom, K. Emanuel, D. Esteban-Fernandez, J. Carswell, and P.S. Chang. Eyewall boundary layer structure in Hurricanes Fabian and Isabel. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 352-353 (2004).

No abstract.

Chave, A.D., D.S. Luther, and C.S. Meinen. Correction of motional electrical field measurements for galvanic distortion. Journal of Atmospheric and Oceanic Technology, 21(2):317-330 (2004).

Interactions between motional electric fields and lateral gradients in electrical conductivity (e.g., seafloor topography) produce boundary electric charges and galvanic (i.e., noninductive) secondary electric fields that result in frequency-independent changes in the electric field direction and amplitude that are specific to a single location. In this paper, the theory of galvanic distortion of the motional electric field is developed from first principles and a procedure to correct for it is then derived. The algorithm is based on estimation of intersite transfer tensors for the horizontal electric fields at the high frequencies where external (ionospheric and magnetospheric) sources, not oceanic motionally induced electric fields, dominate. A decomposition of each measured tensor is derived that expresses it as the product of a set of distortion tensors and the underlying, undistorted transfer tensor. The algorithm may be applied simultaneously to a set of sites and assessed statistically, yielding the undistorted electric field uniquely at each site except for a single site-dependent multiplicative scalar, which must be obtained from other data. Because the distortion is frequency independent, the same tensors may be used to undistort the low-frequency, motional induction components that are of interest in oceanography. This procedure is illustrated using an electric field dataset collected in the Southern Ocean in 1995-97, which is significantly distorted by galvanic processes.

Chen, S.-C., S. Gulati, S. Hamid, X. Huang, L. Luo, N. Morriseau-Leroy, M.D. Powell, C. Zhan, and C. Zhang. A web-based distributed system for hurricane occurrence projection. Software: Practice and Experience, 34(6):549-571 (2004).

As an environmental phenomenon, hurricanes cause significant property damage and loss of life in coastal areas almost every year. Research concerning hurricanes and their aftermath is gaining more and more attention nowadays. This paper presents our work in designing and building a Web-based distributed software system that can be used for the statistical analysis and projection of hurricane occurrences. Firstly, our system is a large-scale system and can handle the huge amount of hurricane data and intensive computations in hurricane data analysis and projection. Secondly, it is a distributed system, which allows multiple users at different locations to access the system simultaneously and to share and exchange the data and data model. Thirdly, our system is a database-centered system where the Oracle database is employed to store and manage the large amount of hurricane data, the hurricane model and the projection results. Finally, a three-tier architecture has been adopted to make our system robust and resistant to the potential change in the lifetime of the system. This paper focuses on the three-tier system architecture, describing the design and implementation of the components at each layer.

Chenoweth, M., and C.W. Landsea. The San Diego hurricane of 2 October 1858. Bulletin of the American Meteorological Society, 85(11):1689-1697 (2004).

On 2 October 1858, estimated sustained hurricane-force winds produced by a tropical cyclone located a short distance offshore were felt in San Diego, California. Unprecedented damage was done in the city and was described as the severest gale ever felt to that date, and it has not been matched or exceeded in severity since. A "southeaster" and high seas from the diminishing tropical cyclone were also felt in the night of 2-3 October at San Pedro (the port serving Los Angeles), California, with shipping interests lightly damaged. The hurricane-force winds at San Diego are the first and only documented instance of winds of this strength from a tropical cyclone in the recorded history of the state. Available evidence suggests that the hurricane tracked just offshore from San Diego, without the eye coming inland, but close enough to produce damaging winds along the entire coast from San Diego to Long Beach, California. The rediscovery of this storm is relevant to climate change issues and the insurance-emergency management communities risk assessment of rare and extreme events in the region.

Coale, K.H., K.S. Johnson, F.P. Chavez, K.O. Buesseler, R.T. Barber, M.A. Brzezinski, W.P. Cochlan, F.J. Millero, P.G. Falkowski, J.E. Bauer, R.H. Wanninkhof, R.M. Kudela, M.A. Altabet, B.E. Hales, T. Takahashi, M.R. Landry, R.R. Bidigare, X. Wang, Z. Chase, P.G. Strutton, G.E. Friederich, M.Y. Gorbunov, V.P. Lance, A.K. Hilting, M.R. Hiscock, M. Demarest, W.T. Hiscock, K.F. Sullivan, S.J. Tanner, R.M. Gordon, C.N. Hunter, V.A. Elrod, S.E. Fitzwater, J.L. Jones, S. Tozzi, M. Koblizek, A.E. Roberts, J. Herndon, J. Brewster, N. Ladizinsky, G. Smith, D. Cooper, D. Timothy, S.L. Brown, K.E. Selph, C.C. Sheridan, B.S. Twining, and Z.I. Johnson. Southern Ocean Iron Enrichment Experiment: Carbon cycling in high and low Si waters. Science, 304(5669):408-414 (2004).

The availability of iron is known to exert a controlling influence on biological productivity in surface waters over large areas of the ocean and may have been an important factor in the variation of the concentration of atmospheric carbon dioxide over glacial cycles. The effect of iron in the Southern Ocean is particularly important because of its large area and abundant nitrate, yet iron-enhanced growth of phytoplankton may be differentially expressed between waters with high silicic acid in the south and low silicic acid in the north, where diatom growth may be limited by both silicic acid and iron. Two mesoscale experiments, designed to investigate the effects of iron enrichment in regions with high and low concentrations of silicic acid, were performed in the Southern Ocean. These experiments demonstrate iron's pivotal role in controlling carbon uptake and regulating atmospheric partial pressure of carbon dioxide.

Cook, S.K., and R.L. Molinari. ENSO observing system, pp. 90-93. In Annual Report on the State of the Ocean and the Ocean Observing System for Climate, D.M. Stanitski (ed.). NOAA Office of Climate Observation, Silver Spring, MD, 307 pp. (2004).

No abstract.

DeGrandpre, M.D., R.H. Wanninkhof, W.R. McGillis, and P.G. Strutton. A Lagrangian study of surface pCO₂ dynamics in the eastern equatorial Pacific Ocean. Journal of Geophysical Research, 109(C8):C08S07, doi:10.1029/2003JC002089 (2004).

We characterized pCO₂ variability on hourly to weekly time scales during the 14-day GasEx-2001 Lagrangian drifter experiment in the eastern equatorial Pacific Ocean. Underway pCO₂ was recorded at 5 m depth as the ship closely followed a drogued drifter. Dissolved O₂ (DO) was measured at 10 and 15 m depths using in situ sensors deployed on the drogue. Diel pCO₂ and DO variability is evaluated using a simple model that accounts for air-sea exchange, vertical mixing, heating, and net community metabolism. Mixed-layer depths and local (vertical) entrainment are estimated with the Price Weller Pinkel (PWP) mixed-layer model. The mean observed pCO₂ was 472.0 � 1.8 µatm with a diel increase of 2-6 µatm on most days, near coincident in time with the diel peak in temperature. The biogeochemical model reveals that heating was the primary source of diel pCO₂ variability, but net community production and depletion of CO₂ in the shallow warm layer due to air-sea gas exchange reduced the heating-driven peak by ~1-4 and 1-2 µatm each day, respectively. The same model parameterizations also accurately predict the diel DO amplitude. In the model, atmospheric exchange depletes total CO₂ and DO in the surface layer, and the depleted water is mixed with the isolated underlying water during nocturnal convection. The 10- and 15-m DO time series corroborate these predicted dynamics. Over the 14-day study, net heating offset the expected ~14 µatm decrease due to air-sea CO₂ exchange and net community production, resulting in a nearly constant mean pCO₂. Consequently, net heating acts to sustain high air-sea CO₂ fluxes in the upwelled equatorial Pacific water as the water advects westward in the South Equatorial Current.

Dodge, P.P., J.F. Gamache, E.W. Uhlhorn, D. Esteban-Fernandez, J. Carswell, and P.S. Chang. Onshore and offshore wind flow regimes at the landfall of Hurricane Isabel (2003). Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 564-565 (2004).

No abstract.

Dugdale, R.C., M. Lyle, F.P. Wilkerson, F. Chai, R.T. Barber, and T.-H. Peng. Influence of equatorial diatom processes on Si deposition and atmospheric CO₂ cycles at glacial/interglacial timescales. Paleoceanography, 19(3):PA3011, doi:10.1029/2003PA000929 (2004).

The causes of the glacial cycle remain unknown, although the primary driver is changes in atmospheric CO₂, likely controlled by the biological pump and biogeochemical cycles. The two most important regions of the ocean for exchange of CO₂ with the atmosphere are the equatorial Pacific and the Southern Ocean (SO), the former a net source and the latter a net sink under present conditions. The equatorial Pacific has been shown to be a Si(OH)₄-limited ecosystem, a consequence of the low source Si(OH)₄ concentrations in upwelled water that has its origin in the SO. This teleconnection for nutrients between the two regions suggests an oscillatory relationship that may influence or control glacial cycles. Opal mass accumulation rate (MAR) data and delta¹⁵N measurements in equatorial cores are interpreted with predictions from a one-dimensional Si(OH)₄-limited ecosystem model (CoSINE) for the equatorial Pacific. The results suggest that equatorial Pacific surface CO₂ processes are in opposite phase to that of the global atmosphere, providing a negative feedback to the glacial cycle. This negative feedback is implemented through the effect of the SO on the equatorial Si(OH)₄ supply. An alternative hypothesis, that the whole ocean becomes Si(OH)₄ poor during cooling periods, is suggested by low opal MAR in cores from both equatorial and Antarctic regions, perhaps as a result of low river input. Terminations in this scenario would result from blooms of coccolithophorids triggered by low Si(OH)₄ concentrations.

Dunion, J.P., and C.S. Velden. The impact of the Saharan air layer on Atlantic tropical cyclone activity. Bulletin of the American Meteorological Society, 85(3):353-365 (2004).

A deep well-mixed, dry adiabatic layer forms over the Sahara Desert and Shale regions of North Africa during the late spring, summer, and early fall. As this air mass advances westward and emerges from the northwest African coast, it is undercut by cool, moist low-level air and becomes the Saharan air layer (SAL). The SAL contains very dry air and substantial mineral dust lifted from the arid desert surface over North Africa, and is often associated with a midlevel easterly jet. A temperature inversion occurs at the base of the SAL where very warm Saharan air overlies relatively cooler air above the ocean surface. Recently developed multispectral Geostationary Operational Environmental Satellite (GOES) infrared imagery detects the SAL's entrained dust and dry air as it moves westward over the tropical Atlantic. This imagery reveals that when the SAL engulfs tropical waves, tropical disturbances, or preexisting tropical cyclones (TCs), its dry air, temperature inversion, and strong vertical wind shear (associated with the midlevel easterly jet) can inhibit their ability to strengthen. The SAL's influence on TCs may be a factor in the TC intensity forecast problem in the Atlantic and may also contribute to this ocean basin's relatively reduced level of TC activity.

Dunion, J.P., C.S. Velden, J.D. Hawkins, and J.R. Parrish. The Saharan air layer: Insights from the 2002 and 2003 Atlantic hurricane seasons. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 495-496 (2004).

No abstract.

Eastin, M.D., P.D. Reasor, J.F. Gamache, F.D. Marks, and M.L. Black. Observed evolution of eyewall convection and low-wavenumber flow in Hurricane Guillermo (1997). Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 445-446 (2004).

No abstract.

Esteban-Fernandez, D., S. Frasier, J. Carswell, P.S. Chang, P.G. Black, and F.D. Marks. Three-dimensional atmospheric boundary layer wind fields from Hurricanes Fabian and Isabel. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 3-4 (2004).

No abstract.

Feely, R.A., and R.H. Wanninkhof. Document ocean carbon sources and sinks, pp. 118-120. In Annual Report on the State of the Ocean and the Ocean Observing System for Climate, D.M. Stanitski (ed.). NOAA Office of Climate Observation, Silver Spring, MD, 307 pp. (2004).

No abstract.

Feely, R.A., and R.H. Wanninkhof. Global repeat hydrographic/CO₂/tracer surveys in support of CLIVAR and global carbon cycle objectives, pp. 121-129. In Annual Report on the State of the Ocean and the Ocean Observing System for Climate, D.M. Stanitski (ed.). NOAA Office of Climate Observation, Silver Spring, MD, 307 pp. (2004).

No abstract.

Feely, R.A., R.H. Wanninkhof, W.R. McGillis, M.-E. Carr, and C.E. Cosca. Effects of wind speed and gas exchange parameterizations on the air-sea CO₂ fluxes in the equatorial Pacific Ocean. Journal of Geophysical Research, 109(C8):C08S03, doi:10.1029/2003JC001896 (2004).

During the recent GasEx-2001 cruise in the equatorial Pacific aboard the NOAA ship Ronald H. Brown, carbon measurements were made in the region of 3°S, 125°W. Continuous surface water fCO₂ measurements were conducted onboard in both underway and discrete analysis modes. During the 15-day experiment, surface water fCO₂ values averaged 473 � 2 µatm, providing a constant condition of supersaturation and flux of CO₂ from the ocean to the atmosphere. The relationship of gas transfer with wind speed developed in this study is used along with regional estimates of air-water fCO₂ differences to determine CO₂ fluxes in the equatorial Pacific. The regional fCO₂ fields are estimated from algorithms developed from previous measurements collected on the Ronald H. Brown and Ka'imimoana over the past 10 years between 5°N and 10°S, 90°W and 165°E. Using the W. McGillis et al. gas transfer-wind speed relationship, we estimate an average flux of 1.5 � 0.4 mol C m^-2 yr^-1 for the study region, with a six-fold difference in the regional efflux of CO₂ between the strong El Ni�o events of 1986-1987 and 1997-1998 and the La Ni�a events of 1996 and 1999-2001 (i.e., 0.1 to 0.56 Pg C yr^-1). The combined effects of uncertainties in the gas transfer velocity and wind fields lead to average difference of 27% between the lowest and highest estimates of the CO² flux from the region. In contrast, the uncertainties in the fCO₂-SST relationships give an average difference of about 35% between the lowest and highest estimates of the CO₂ flux.

Feuer, S.E., C.W. Landsea, L. Woolcock, and J.O. Berkeley. The reanalysis of Atlantic basin tropical cyclones from the 1920s: A reexamination of three catastrophic hurricanes that impacted Florida. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 669-670 (2004).

No abstract.

Fonseca, C., G.J. Goni, W. Johns, and E. Campos. Investigation of the North Brazil Current retroflection and North Equatorial Countercurrent variability. Geophysical Research Letters, 31(21):L21304, doi:10.1029/2004GL020054 (2004).

Eight years of TOPEX/Poseidon altimeter-derived sea height anomaly and climatological hydrographic data are used to investigate the temporal and spatial variability of the North Brazil Current (NBC) retroflection and the North Equatorial Countercurrent (NECC). The NBC retroflection exhibits a mean position of 6.6°N � 2.0°, with a strong annual signal and year-to-year variability. The annual cycle of its location follows the meridional migration of the ITCZ and the strength of the wind stress curl over the equatorial Atlantic. A marked shift in the annual mean location of the NBC retroflection is observed in 1998-1999 that appears to be linked to an increase in wind stress curl during this period. The mean latitude of the NECC is estimated to be 6.0°N � 1.3°, with a semiannual cycle showing maximum northerly locations in February and August. The baroclinic transport of the NECC varies predominantly on an annual cycle with maximum transport of 12 Sv occurring in November.

Forde, E.B. Severe weather. Science Scope, 27(7):33-35 (2004).

No abstract.

Forde, E.B. Severe weather. The Science Teacher, 71(4):42-44 (2004).

No abstract.

French, J.R., and P.G. Black. Turbulent flux measurements within a hurricane boundary layer from an instrumented aircraft. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 9-10 (2004).

No abstract.

Gamache, J.F., J.S. Griffin, P.P. Dodge, and N.F. Griffin. Automatic Doppler analysis of three-dimensional wind fields in hurricane eyewalls. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 164-165 (2004).

No abstract.

Garzoli, S.L., A. Ffield, W.E. Johns, and Q. Yao. North Brazil Current retroflection and transports. Journal of Geophysical Research, 109(C1):1013, doi:10.1029/2003JC001775 (2004).

A subset of data collected as a part of a larger program, the North Brazil Current Rings (NBCR) Experiment, is analyzed to study the variability of the transport of the North Brazil Current (NBC) and its relation with the shedding of rings. It is concluded that there is a direct relation between the latitude of penetration, the number of rings shed, and the intensity of the NBC. The data set consists of dynamic height time series derived from three inverted echo sounders and a shallow pressure gauge deployed along a section perpendicular to the South American coast between the continent and 7°N, and between 48° and 45°W. Velocity and hydrographic data collected during the NBCR cruises are also analyzed and used to validate the results. The 15-month mean transport of the NBC is 16 � 2 Sv. The 18-month mean of the retroflected southeastward flow is 22 � 2 Sv. Both flows display considerable variability. The retroflected southeast flow reaches its maximum value during September 1999, near the time when the climatological North Equatorial Countercurrent (NECC) reaches its maximum strength and it is minimum when the climatological NECC reverses or is not present in the basin. The mean difference between the NBC flow and the retroflected flow during August-December 1999 when the NECC is fully established is -7 Sv. The excess in the retroflected flow is due to North Atlantic water joining the retroflected flow from the South Atlantic. The combination of both flows constitutes the NECC.

Garzoli, S.L., G.J. Goni, M.O. Baringer, and R.L. Molinari. Implementation of high density XBT lines in the Atlantic Ocean, pp. 135-143. In Annual Report on the State of the Ocean and the Ocean Observing System for Climate, D.M. Stanitski (ed.). NOAA Office of Climate Observation, Silver Spring, MD, 307 pp. (2004).

No abstract.

Garzoli, S.L., R. Lumpkin, M. Pazos, and C. Engler. Tropical and subtropical Atlantic layer studies, pp. 130-134. In Annual Report on the State of the Ocean and the Ocean Observing System for Climate, D.M. Stanitski (ed.). NOAA Office of Climate Observation, Silver Spring, MD, 307 pp. (2004).

No abstract.

Goni, G.J., M. DeMaria, J.A. Trinanes, and P.G. Black. Testing global estimates of the tropical cyclone heat potential fields to improve hurricane intensification prediction. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 7-8 (2004).

No abstract.

Goodwin, K.D., G. Scorzetti, S.A. Cotton, T.L. Kiesling, P.B. Ortner, and J.W. Fell. Detection of Karenia brevis by a microtiter plate assay. In Harmful Algae 2002, Proceedings, 10th International Conference on Harmful Algae, St. Pete Beach, FL, October 21-25, 2002, K.A. Steidinger, J.H. Landsberg, C.R. Tomas, and G.A. Vargo (eds.). Florida Fish and Wildlife Conservation Commission, Florida Institute of Oceanography, and Intergovernmental Oceanographic Commission of UNESCO, 225-227 (2004).

A new well-plate assay was developed that detects Karenia brevis and Amphidinium carterae DNA from cultures and environmental samples. Extracted DNA was amplified using universal biotinylated primers, and amplicons were hybridized to species-specific probes, which were immobilized onto well-plate surfaces. Molecular probes were based on rDNA sequences. This method yielded quick colorimetric results and conserved DNA by using only one amplification step. Detection of both toxic dinoflagellates was achieved using one hybridization condition, and K. brevis and A. carterae did not cross-react. The assay holds promise as a quick method to simultaneously test water samples for a variety of toxic organisms.

Grigorieva, N.G., G.M. Fridman, and D.R. Palmer. Investigation of near-axial interference effects for propagation in a ducted waveguide. Proceedings, Sixth International Conference on Theoretical and Computational Acoustics, Honolulu, HI, August 11-15, 2003. World Scientific Publishing, 129-134 (2004).

The observed time-of-arrival patterns from a number of long-range ocean acoustic propagation experiments show early geometrical-like arrivals followed by a crescendo of energy that propagates along the sound-channel axis and is not resolved into individual arrivals. To describe in a simple model case the interference of near-axial waves which resulted in forming the so-called axial wave and propose formulas for the axial wave in more general cases, the two-dimensional reference point source problem for the parabolic index of refraction squared is investigated. The integral representation for the exact solution is transformed in such a way to extract ray summands corresponding to rays radiated from the source at angles less than a certain angle, the axial wave, and a term corresponding to a sum of all the rays having launch angles greater than the indicated angle. Numerical results for the axial wave are obtained for parameters corresponding to long-range ocean acoustic propagation experiments.

Guo, L., J.-Z. Zhang, and C. Gueguen. Speciation and fluxes of nutrients (N, P, Si) from the upper Yukon River. Global Biogeochemical Cycles, 18(1):GB1038, doi:10.1029/2003GB002152 (2004).

Water samples were collected from the Yukon River near the Stevens Village Station from May to September 2002 and analyzed for nutrients (N, P, and Si) in dissolved, particulate, organic, and inorganic forms to examine temporal variations in nutrient concentrations, fluxes, and phase partitioning. Both NO₃ and PO₄ concentrations in the Yukon River were much lower than those of world rivers, with an average concentration of 2.43 � 0.63 µM-N and 0.053 � 0.040 µM-P, respectively. Si(OH)₄ concentrations were more comparable to those of world rivers, with an average concentration of 82 � 21 µM-Si. Integrated annual fluxes were 2.4 x 10⁸ mole-NO₃, 3.4 x 10⁶ mole-PO₄, and 8.7 x 10⁹ mole-Si(OH)₄, respectively. Nutrient discharge during the river ice open season contributed 73 to 95% of the annual flux depending on nutrient species. Within the total N pool transported by the Yukon River, dissolved inorganic N comprised 7 � 4% and particulate N made up 25 � 10%, while dissolved organic N (DON) was the dominant N species (with an average of 67 � 10%). In contrast, P was predominantly partitioned in the particulate phase (with an average of 94 � 6%), leaving 4 � 5% of the total P in the dissolved organic phase and ~2 � 1% in the dissolved inorganic phase. The partitioning of N and P indicates that the transformation between dissolved and particulate or inorganic and organic phases may play a critical role in controlling the flux of bioavailable nutrients and thus the nutrient dynamics in the Yukon River Basin and its coastal region. Nutrient specific fluxes normalized to drainage area in the Yukon River Basin were 0.57 mmole/m²/yr for NO₃, 0.012 mmole/m²/yr for PO₄, and ~19 mmole/m²/yr for Si(OH)₄, respectively. The relatively low specific fluxes of NO₃ and PO₄ in the Yukon River Basin reflect its pristine status or little anthropogenic influence, whereas cold climate in the Arctic/subarctic region may be responsible for its lower Si(OH)₄ specific flux, in agreement with a general trend of increasing Si specific flux with decreasing latitude in global river systems. A warming climate and thus deeper permafrost active layer in the Yukon River watershed would likely enhance the export flux of nutrients into the Bering Sea.

Hansell, D.A., H.W. Ducklow, A.M. Macdonald, and M.O. Baringer. Metabolic poise in the North Atlantic Ocean diagnosed from organic matter transports. Limnology and Oceanography, 49(4):1084-1094 (2004).

Recently there has been discussion about the metabolic state of the ocean, with arguments questioning whether the open ocean is net autotrophic or net heterotrophic. Accurately determining the metabolic balance of a marine system depends on fully defining the system being evaluated and on quantifying the inputs and outputs to that system. Here, a net northward transport of dissolved organic carbon (DOC) (across 24.5°N) of 3.3 � 1.9 Tmol C yr^-1 was determined using basin-wide transport estimates of DOC. This flux, coupled with DOC inputs from the Arctic Ocean (2.2 � 0.8 Tmol C yr^-1), the atmosphere (0.6 � 0.08 Tmol C yr^-1), and rivers (3.1 � 0.6 Tmol C yr^-1), indicates net heterotrophy in the North Atlantic (full depth, 24.5-72°N) of 9.2 � 2.2 Tmol C yr^-1. This rate is small (<2%) compared to autochthonous production (~494 Tmol C yr^-1) and consumption (production:respiration of 0.98), indicating that the North Atlantic is essentially metabolically balanced and that autochthonous production is remineralized within the basin. The upper layer of the subtropical gyre has previously been reported to exhibit high rates of net heterotrophy, but our analysis does not support those findings. Instead, allochthonous inputs of organic carbon to the upper subtropical gyre are an order of magnitude less than required by the elevated rates of net heterotrophy reported. We find, too, that net mineralization of allochthonous DOC within the basin could account for 10% of the preindustrial inorganic carbon exported from the basin to the south. Two factors, the import of organic matter and the unique thermohaline circulation pattern of the North Atlantic, are primary in ensuring net heterotrophy in the basin.

Harasti, P.R., C.J. McAdie, P.P. Dodge, W.-C. Lee, J. Tuttle, S.T. Murillo, and F.D. Marks. Real-time implementation of single-Doppler radar analysis methods for tropical cyclones: Algorithm improvements and use with WSR-88D display data. Weather and Forecasting, 19(2):219-239 (2004).

The NOAA/NWS/NCEP/Tropical Prediction Center/National Hurricane Center has sought techniques that use single-Doppler radar data to estimate the tropical cyclone wind field. A cooperative effort with NOAA/Atlantic Oceanographic and Meteorological Laboratory/Hurricane Research Division and NCAR has resulted in significant progress in developing a method whereby radar display data are used as a proxy for a full-resolution base data and in improving and implementing existing wind retrieval and center-finding techniques. These techniques include the ground-based velocity track display (GBVTD), tracking radar echoes by correlation (TREC), GBVTD-simplex, and the principal component analysis (PCA) methods. The GBVTD and TREC algorithms are successfully applied to the Weather Surveillance Radar-1988 Doppler (WSR-88D) display data of Hurricane Bret (1999) and Tropical Storm Barry (2001). GBVTD analyses utilized circulation center estimates provided by the GBVTD-simplex and PCA methods, whereas TREC analyses utilized wind center estimates provided by radar imagery and aircraft measurements. GBVTD results demonstrate that the use of the storm motion as a proxy for the mean wind is not always appropriate and that results are sensitive to the accuracy of the circulation center estimate. TREC results support a previous conjecture that the use of polar coordinates would produce improved wind retrievals for intense tropical cyclones. However, there is a notable effect in the results when different wind center estimates are used as the origin of coordinates. The overall conclusion is that GBVTD and TREC have the ability to retrieve the intensity of a tropical cyclone with an accuracy of ~2 m s^-1 or better if the wind intensity estimates from individual analyses are averaged together.

Hare, J.E., C.W. Fairall, W.R. McGillis, J.B. Edson, B. Ward, and R.H. Wanninkhof. Evaluation of the National Oceanic and Atmospheric Administration/Coupled-Ocean Atmospheric Response Experiment (NOAA/COARE) air-sea gas transfer parameterization using GasEx data. Journal of Geophysical Research, 109(C8):C08S11, doi:10.1029/2003JC001831 (2004).

During the two recent GasEx field experiments, direct covariance measurements of air-sea carbon dioxide fluxes were obtained over the open ocean. Concurrently, the National Oceanic and Atmospheric Administration/Coupled-Ocean Atmospheric Response Experiment air-sea gas transfer parameterization was developed to predict gas transfer velocities from measurements of the bulk state of the sea surface and atmosphere. The model output is combined with measurements of the mean air and sea surface carbon dioxide fugacities to provide estimates of the air-sea CO₂ flux, and the model is then tuned to the GasEx-1998 data set. Because of differences in the local environment and, possibly, because of weaknesses in the model, some discrepancies are observed between the predicted fluxes from the GasEx-1998 and GasEx-2001 cases. To provide an estimate of the contribution to the air-sea flux of gas due to wave-breaking processes, the whitecap and bubble parameterizations are removed from the model output. These results show that moderate (approximately 15 m s^-1) wind speed breaking wave gas transfer processes account for a fourfold increase in the flux over the modeled interfacial processes.

Hendee, J.C. The Coral Reef Early Warning System (CREWS): Marine environmental monitoring to support research and marine sanctuary management, pp. 23-25.In The Effects of Combined Sea Temperature, Light, and Carbon Dioxide on Coral Bleaching, Settlement, and Growth, J.C. Hendee (ed.). NOAA Research Special Report, Silver Spring, MD, 126 pp. (2004).

No abstract.

Hood, R.E., D. Cecil, F.J. LaFontaine, R. Blakeslee, D. Mach, G.M. Heymsfield, and F.D. Marks. Classification of tropical oceanic precipitation using high altitude aircraft microwave and electric field measurements. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 172-173 (2004).

No abstract.

Houston, S.H., and P.P. Dodge. Comparison of GPS-sonde observations and surface data: An update. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 376 (2004).

No abstract.

Howard, J.R., A.L. Doggett, R.E. Peterson, P.G. Black, J.L. Schroeder, D.A. Smith, and J.P. Dunyak. Transition in onshore hurricane boundary layer winds during the landfall of Hurricane Lili (2002). Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 526-527 (2004).

No abstract.

Hu, C., F.E. Muller-Karger, G.A. Vargo, M.B. Neely, and E. Johns. Linkages between coastal runoff and the Florida Keys ecosystem: A study of a dark plume event. Geophysical Research Letters, 31(15):L15307, doi:10.1029/2004GL020382 (2004).

Using data collected by satellite sensors, rain and river gauges, and ship surveys, we studied the development and wind-driven transport of a dark water plume from near Charlotte Harbor, Florida, to the Dry Tortugas in the Florida Keys in mid-October 2003. MODIS and SeaWiFS imagery showed that the patch contained an extensive (~5,500 km²) phytoplankton bloom that formed originally near the central coast of Florida. The data linked the bloom to high nutrient coastal runoff caused by heavy rainfall in June and August. Total N and P required for the bloom, which may contain some Karenia brevis cells, was estimated to be 2.3 x 10⁷ and 1.5 x 10⁶ moles, respectively. The dark color became increasingly dominated by colored dissolved organic matter, toward the Dry Tortugas, where CDOM absorption coefficients (0.08-0.12 m^-1 at 400 nm) were 2-3 times higher than the surrounding shelf waters, while chlorophyll and inorganic nutrients decreased to negligible levels.

Huang, W.-P., C.-C. Wu, P.-H. Lin, S.D. Aberson, and K.-C. Hsu. The preliminary analysis of the dropsonde data from DOTSTAR and their impact on the typhoon track forecasts. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 188-189 (2004).

No abstract.

Jacob, S.D., L.K. Shay, G.R. Halliwell, C.J. Koblinsky, and M.D. Powell. Surface fluxes and upper ocean budgets during 2002 Hurricanes Isidore and Lili. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 617-618 (2004).

No abstract.

Jones, R.W., and H.E. Willoughby. Vortex alignment on the f and beta plane. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 625-626 (2004).

No abstract.

Jones, S.C., C.S. Velden, S.D. Aberson, J. Abraham, and P.A. Harr. Extratropical transition and THORPEX. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 643-644 (2004).

No abstract.

Kaplan, J., and M. DeMaria. Estimating the probability of rapid intensification of tropical cyclones in the Atlantic and eastern Pacific basins. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 538-539 (2004).

No abstract.

Katsaros, K.B., and A.V. Soloviev. Reduced horizontal sea surface temperature gradients under conditions of clear sky and weak winds. Preprints, 8th Symposium on Integrated Observing and Assimilation Systems for Atmosphere, Oceans, and Land Surface, Seattle, WA, January 11-15, 2004. American Meteorological Society, Boston, 2 pp. (CD-ROM) (2004).

No abstract.

Katsaros, K.B., and A.V. Soloviev. Vanishing sea surface temperature gradients at low wind speeds. Boundary-Layer Meteorology, 112(2):381-396 (2004).

Sea surface temperature (SST) is a result of multiple interactions in air-sea processes. During days with strong insolation and low wind speed, there may be uneven net heating of the water layer near the surface of the ocean, when there are horizontal temperature gradients at the sea surface. Cooling of the water caused by evaporation, sensible, or longwave radiative heat loss would be greater from warm water compared to that from relatively colder water. As a result, under low wind speed conditions and clear skies, the horizontal SST discontinuities, occurring at fronts, eddies, or in storm wakes, may diminish or even vanish. This phenomenon is illustrated here with some field and modeling results. The dependence of the difference in warming on the cold and warm side of SST discontinuities is explored for its dependence on latitude and mean environmental conditions. The time dependence is important for the impact on remote sensing of SST, and it is found to be short enough that substantial masking of SST gradients can occur during the first six hours of the diurnal heating cycle, but the effect would continue to grow if calm and solar heating persist for several subsequent days. An integrated effect of this uneven net heating is seen in the seasonal masking of subsurface temperature gradients in the Gulf of Mexico and Florida Straits.

Key, R.M., A. Kozyr, C.L. Sabine, K. Lee, R. Wanninkhof, J.L. Bullister, R.A. Feely, F.J. Millero, C. Mordy, and T.-H. Peng. A global ocean carbon climatology: Results from Global Data Analysis Project (GLODAP). Global Biogeochemical Cycles, 18(4):GB40301, doi:10.1029/2004GB002247 (2004).

During the 1990s, ocean sampling expeditions were carried out as part of the World Ocean Circulation Experiment (WOCE), the Joint Global Ocean Flux Study (JGOFS), and the Ocean Atmosphere Carbon Exchange Study (OACES). Subsequently, a group of U.S. scientists synthesized the data into easily usable and readily available products. This collaboration is known as the Global Ocean Data Analysis Project (GLODAP). Results were merged into a common format data set, segregated by ocean. For comparison purposes, each ocean data set includes a small number of high-quality historical cruises. The data were subjected to rigorous quality control procedures to eliminate systematic data measurement biases. The calibrated 1990s data were used to estimate anthropogenic CO₂, potential alkalinity, CFC watermass ages, CFC partial pressure, bomb-produced radiocarbon, and natural radiocarbon. These quantities were merged into the measured data files. The data were used to produce objectively gridded property maps at a 1° resolution on 33 depth surfaces chosen to match existing climatologies for temperature, salinity, oxygen, and nutrients. The mapped fields are interpreted as an annual mean distribution in spite of the inaccuracy in that assumption. Both the calibrated data and the gridded products are available from the Carbon Dioxide Information Analysis Center. Here we describe the important details of the data treatment and the mapping procedure, and present summary quantities and integrals for the various parameters.

Kossin, J.P., W.H. Schubert, C.S. Velden, M.L. Black, P.G. Black, R.M. Zehr, S.D. Aberson, and J.P. Dunion. Mesovortices in Hurricane Isabel (2003). Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 447-448 (2004).

No abstract.

Landsea, C.W., C. Anderson, N. Charles, G. Clark, J.P. Dunion, J. Fernandez-Partagas, P. Hungerford, C. Neumann, and M. Zimmer. The Atlantic hurricane database re-analysis project: Documentation for the 1851-1910 alterations and additions to the HURDAT database. In Hurricanes and Typhoons: Past, Present, and Future, R.J. Murnane and K.-B. Liu (eds.). Columbia University Press (ISBN 0-231-12388-4), 177-221 (2004).

No abstract.

Landsea, C.W., J.L. Franklin, C.J. McAdie, J.L. Beven, J.M. Gross, B.R. Jarvinen, R.J. Pasch, E.N. Rappaport, J.P. Dunion, and P.P. Dodge. A reanalysis of Hurricane Andrew's intensity. Bulletin of the American Meteorological Society, 85(11):1699-1712 (2004).

Hurricane Andrew of 1992 caused unprecedented economic devastation along its path through the Bahamas, southeastern Florida, and Louisiana. Damage in the United States was estimated to be $26 billion (in 1992 dollars), making Andrew one of the most expensive natural disasters in U.S. history. This hurricane struck southeastern Florida with maximum 1-min surface winds estimated in a 1992 post-storm analysis at 125 kt (64 m s^-1). This original assessment was primarily based on an adjustment of aircraft reconnaissance flight-level winds to the surface. Based on recent advancements in the understanding of the eyewall wind structure of major hurricanes, the official intensity of Andrew was adjusted upward for five days during its track across the Atlantic Ocean and Gulf of Mexico by the National Hurricane Center Best Track Change Committee. In particular, Andrew is now assessed by the National Hurricane Center to be a Saffir-Simpson Hurricane Scale category-5 hurricane (the highest intensity category possible) at its landfall in southeastern Florida, with maximum 1-min winds of 145 kt (75 m s^-1). This makes Andrew only the third category-5 hurricane to strike the United States since at least 1900. Implications for how this change impacts society's planning for such extreme events are discussed.

Lawrence, D., M.J. Dagg, H. Liu., S.R. Cummings, P.B. Ortner, and C.R. Kelble. Wind events and benthic-pelagic coupling in a shallow subtropical bay in Florida. Marine Ecology Progress Series, 266:1-13 (2004).

During the winter months (December to April), the southeast United States is influenced by continental air masses from the north or northwest which pass at approximately 4 to 7 d intervals. These wind events can cause suspension of bottom sediments in Florida Bay. Over a 9 d period in March 2001, we examined the effects of a wind-mixing event on the pelagic system within the northwest part of Florida Bay, where water depth is 2 to 3 m. This event caused significant suspension of bottom materials, large increases in NH₄ and PO₄, smaller increases in NO₃+NO₂ and Si(OH)₄, a decrease in microzooplankton abundance, and an increase in benthic copepods in the water column. As wind speeds declined, there was a rapid decline in PO₄ concentration, gradual declines in suspended sediment, NH₄ and Si(OH)₄, an increase in chlorophyll a (chl a) stock, an increase in phytoplankton growth and productivity, an increase in microzooplankton grazing rate, and a settling of the benthic harpacticoid community. No grazing response was apparent in the mesozooplankton community. The wind event clearly injected dissolved and particulate benthic materials into the water column, where they directly stimulated the bacterioplankton, phytoplankton and microzooplankton communities within 1 to 2 d after the event. The water column was strongly net heterotrophic at this time, suggesting a large input of dissolved organic matter from the bottom. Stimulation of the pelagic food web continued at least until we completed our study 6 d after the event. By the end of our study, the water column was net autotrophic.

Lonfat, M., F.D. Marks, and S.S. Chen. Precipitation distribution in tropical cyclones using the Tropical Rainfall Measuring Mission (TRMM) microwave imager: A global perspective. Monthly Weather Review, 132(7):1645-1660 (2004).

TRMM microwave imager rain estimates are used to quantify the spatial distribution of rainfall in tropical cyclones (TCs) over the global oceans. A total of 260 TCs were observed worldwide from 1 January 1998-31 December 2000, providing 2,121 instantaneous TC precipitation observations. To examine the relationship between the storm intensity, its geographical location, and the rainfall distribution, the data set is stratified into three intensity groups and six oceanic basins. The three intensity classes used in this study are tropical storms (TSs) with winds <33 m s^-1, category 1-2 hurricane-strength systems (CAT12) with winds from 34-48 m s^-1, and category 3-5 systems (CAT35) with winds >49 m s^-1. The axisymmetric component of the TC rainfall is represented by the radial distribution of the azimuthal mean rainfall rates (R). The mean rainfall distribution is computed using 10-km annuli from the storm center to a 500-km radius. The azimuthal mean rain rates vary with storm intensity and from basin to basin. The maximum R is about 12 mm h^-1 for CAT35, but decreases to 7 mm h^-1 for CAT12, and to 3 mm h^-1 for TS. The radius from the storm center of the maximum rainfall decreases with increasing storm intensity, from 50 km for TS to 35 km for CAT35 systems. The asymmetric component is determined by the first-order Fourier decomposition in a coordinate system relative to the storm motion. The asymmetry in TC rainfall varies significantly with both storm intensity and geographic locations. For the global average of all TCs, the maximum rainfall is located in the front quadrants. The location of the maximum rainfall shifts from the front-left quadrant for TS to the front-right for CAT35. The amplitude of the asymmetry varies with intensity as well; TS shows a larger asymmetry than CAT12 and CAT35. These global TC rainfall distributions and variability observed in various ocean basins should help to improve TC rainfall forecasting worldwide.

Majumdar, S.J., S.D. Aberson, B.J. Etherton, L.D. Holland, Z. Toth, and C.H. Bishop. Targeting strategies to improve hurricane track forecasts. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 190-191 (2004).

No abstract.

Manzello, D. A decade of SEAKEYS data: SST trends and patterns, pp. 35-36. In The Effects of Combined Sea Temperature, Light, and Carbon Dioxide on Coral Bleaching, Settlement, and Growth, J.C. Hendee (ed.). NOAA Research Special Report, Silver Spring, MD, 126 pp. (2004).

No abstract.

McFarquhar, G.M., and R.A. Black. Hurricane observations of particle size and phase and their implications for mesoscale modeling of microphysical processes. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 348-349 (2004).

No abstract.

McFarquhar, G.M., and R.A. Black. Observations of particle size and phase in tropical cyclones: Implications for mesoscale modeling of microphysical processes. Journal of the Atmospheric Sciences, 61(4):422-439 (2004).

Mesoscale model simulations of tropical cyclones are sensitive to representations of microphysical processes, such as fall velocities of frozen hydrometeors. The majority of microphysical parameterizations are based on observations obtained in clouds not associated with tropical cyclones, and hence their suitability for use in simulations of tropical cyclones is not known. Here, representations of mass-weighted fall speed V_m for snow and graupel are examined to show that parameters describing the exponential size distributions and fall speeds of individual hydrometeors [through use of relations such as V(D) = aD^b are identically important for determining V_m. The a and b coefficients are determined by the composition and shape of snow and graupel particles; past modeling studies have not adequately considered the possible spread of a and b values. Step variations in these coefficients, associated with different fall velocity regimes, however, do not have a large impact on V_m for observed size distributions in tropical cyclones and the values of a and b used here, provided that coefficients are chosen in accordance with the sizes where the majority of mass occurs. New parameterizations for V_m are developed such that there are no inconsistencies between the diameters used to define the mass, number concentration, and fall speeds of individual hydrometeors. Effects due to previous inconsistencies in defined diameters on mass conversion rates between different hydrometeor classes (e.g., snow, graupel, cloud ice) are shown to be significant. In situ microphysical data obtained in Hurricane Norbert (1984) and Hurricane Emily (1987) with two-dimensional cloud and precipitation probes are examined to determine typical size distributions of snow and graupel particles near the melting layer. Although well represented by exponential functions, there are substantial differences in how the intercept and slope of these distributions vary with mass content when compared to observations obtained in other locations; most notably, the intercepts of the size distributions associated with tropical cyclones increase with mass content, whereas some observations outside tropical cyclones show a decrease. Differences in the characteristics of the size distributions in updraft and downdraft regions, when compared to stratiform regions, exist, especially for graupel. A new representation for size distributions associated with tropical cyclones is derived and has significant impacts on the calculation of V_m.

McFarquhar, G.M., H. Zhang, G.M. Heymsfield, J. Dudhia, J.B. Halverson, R.E. Hood, and F.D. Marks. A modeling and observational study of the impacts of microphysical processes on the evolution of Hurricane Erin (2001). Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 520-521 (2004).

No abstract.

McGillis, W.R., W.E. Asher, R.H. Wanninkhof, A.T. Jessup, and R.A. Feely. Introduction to special section: Air-sea exchange. Journal of Geophysical Research, 109(C8):C08S01, doi:10.1029/2004JC002605 (2004).

No abstract.

McGillis, W.R., J.B. Edson, C.J. Zappa, J.D. Ware, S.P. McKenna, E.A. Terray, J.E. Hare, C.W. Fairall, W. Drennan, M. Donelan, M.D. DeGrandpre, R.H. Wanninkhof, and R.A. Feely. Air-sea CO₂ exchange in the equatorial Pacific. Journal of Geophysical Research, 109(C8):C08S02, doi:10.1029/2003JC002256 (2004).

GasEx-2001, a 15-day air-sea carbon dioxide (CO₂) exchange study conducted in the equatorial Pacific, used a combination of ships, buoys, and drifters equipped with ocean and atmospheric sensors to assess variability and surface mechanisms controlling air-sea CO₂ fluxes. Direct covariance and profile method air-sea CO₂ fluxes were measured together with the surface ocean and marine boundary layer processes. The study took place in February 2001 near 125°W, 3°S in a region of high CO₂. The diurnal variation in the air-sea CO₂ difference was 2.5%, driven predominantly by temperature effects on surface solubility. The wind speed was 6.0 � 1.3 m s^-1, and the atmospheric boundary layer was unstable with conditions over the range -1 < z/L < 0. Diurnal heat fluxes generated daytime surface ocean stratification and subsequent large nighttime buoyancy fluxes. The average CO₂ flux from the ocean to the atmosphere was determined to be 3.9 mol m^-2 yr^-1, with nighttime CO₂ fluxes increasing by 40% over daytime values because of a strong nighttime increase in (vertical) convective velocities. The 15 days of air-sea flux measurements taken during GasEx-2001 demonstrate some of the systematic environmental trends of the eastern equatorial Pacific Ocean. The fact that other physical processes, in addition to wind, were observed to control the rate of CO₂ transfer from the ocean to the atmosphere indicates that these processes need to be taken into account in local and global biogeochemical models. These local processes can vary on regional and global scales. The GasEx-2001 results show a weak wind dependence but a strong variability in processes governed by the diurnal heating cycle. This implies that any changes in the incident radiation, including atmospheric cloud dynamics, phytoplankton biomass, and surface ocean stratification may have significant feedbacks on the amount and variability of air-sea gas exchange. This is in sharp contrast with previous field studies of air-sea gas exchange, which showed that wind was the dominating forcing function. The results suggest that gas transfer parameterizations that rely solely on wind will be insufficient for regions with low to intermediate winds and strong insolation.

McNoldy, B.D., M.D. Eastin, C.M. Rozoff, and W.H. Schubert. Multiple eyewall structure of Hurricane Juliette (2001). Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 126-127 (2004).

No abstract.

Meinen, C.S., S.L. Garzoli, W.E. Johns, and M.O. Baringer. Transport variability of the Deep Western Boundary Current and the Antilles Current off Abaco Island, Bahamas. 51(11):1397-1415 (2004).

Hydrography is combined with one-year-long Inverted Echo Sounder (IES) travel-time records and bottom pressure observations to estimate the Deep Western Boundary Current (DWBC) transport east of Abaco Island, the Bahamas (near 26.5°N); comparison of the results to a more traditional line of current meter moorings demonstrates that the IESs and pressure gauges, combined with hydrography, can accurately monitor the DWBC transport to within the accuracy of the current meter array estimate at this location. Between 800 and 4800 dbar, bounded by two IES moorings 82 km apart, the enclosed portion of the DWBC is shown to have a mean southward transport of about 25 Sv (1 SV = 10⁶ m³ s^-1) and a standard deviation of 23 Sv. The DWBC transport is primarily barotropic (where barotropic is defined as the near-bottom velocity rather than the vertical average velocity); geostrophic transports relative to an assumed level of no motion do not accurately reflect the actual absolute transport variability (correlation coefficient is 0.30). The IES-pressure gauge absolute transport within 1200-4800 dbar agrees well with the current meter absolute transports (upper integration limit based on shallowest current meter level); the standard deviation of the difference is 12 Sv and the mean difference is 0.2 Sv. The correlation coefficient between these two time series is 0.76. The northward flowing Antilles Current (AC) east of Abaco Island has a mean baroclinic transport of 6 Sv as estimated by the IESs and a standard deviation of 3 Sv. The AC variations observed during 1996-1997 are uncorrelated with the Florida Current transport variations west of Abaco Island in the Florida Straits; however, the AC transport variations bear some resemblance to the historical estimates of the AC annual cycle.

Molinari, R.L. Annual and decadal variability in the western subtropical North Atlantic: Signal characteristics and sampling methodologies. Progress in Oceanography, 62(1):33-66 (2004).

Upper ocean (above 750 m) temperature structure of the northwestern subtropical Atlantic, including the Gulf Stream and a recirculation gyre south of the Stream, is characterized using primarily bathythermograph (BT) data collected between 1950 and 2003. Geostrophic calculations, using mean temperature-salinity relationships to compute dynamic height, are used to estimate velocities and transports. The mean annual Gulf Stream transport at 72°W relative to 750 m, 36.1 Sv, is approximately equal to the sum of the transport of the Florida Current, 32.0 Sv, and a shallow recirculation gyre described by Wang and Koblinsky [Journal of Physical Oceanography, 26 (1996) 2462-2479], 5.5 Sv. The annual cycle of geostrophic transport relative to 750 m at 72°W is in phase with both an earlier published annual cycle of transport relative to 2000 m derived from hydrographic observations and the annual cycle of Florida Current transport measured indirectly by a submarine cable (i.e., maximum transports are observed in the summer and minimum in the fall, early winter). However, simple Sverdrup dynamics are inadequate to explain these cycles as maximum Sverdrup transports extend from winter to summer, while observed transports are minimum (maximum) in fall/winter (summer). The annual cycles derived from the BT data of the size of the shallow southern recirculation gyre, Gulf Stream position and upper layer transport (relative to 300 m) are in phase (maximum size, northern position and transport in fall) and consistent with the WK results derived from altimetry. However, the shallower annual cycles are out of phase with the deeper signals (i.e., maximum for the former (latter) are observed in fall (summer)). Decadal signals after 1965 in Gulf Stream position, geostrophic transport relative to 450 m, and the size of a recirculation gyre south of the Stream are approximately in phase as observed for the annual signal. This gyre and the shallow WK gyre exhibit the same horizontal structure, however, the decadal signal propagates deeper into the water column (at least to 700 m). The eastern expansion and contraction of the gyre on decadal time-scales is correlated with propagating SST signals. The sampling implications of these findings are addressed.

Murillo, S.T., P.P. Dodge, W.-C. Lee, and G.M. Barnes. Implementing a single-Doppler radar technique for tropical cyclones and integrating radar-derived wind fields into H*Wind surface analyses. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 606-607 (2004).

No abstract.

Olsen, A., J.A. Trinanes, and R. Wanninkhof. Sea-air flux of CO₂ in the Caribbean Sea estimated using in situ and remote sensing data. Remote Sensing of Environment, 89(3):309-325 (2004).

Empirical relationships between sea surface carbon dioxide fugacity (fCO₂^sw) and sea surface temperature (SST) were applied to data sets of remotely sensed SST to create fCO₂^sw fields in the Caribbean Sea. SST data sets from different sensors were used, as well as the SST fields created by optimum interpolation of bias corrected AVHRR data. Empirical relationships were derived using shipboard fCO₂^sw data, in situ SST data, and SST data from the remote sensing platforms. The results show that the application of a relationship based on shipboard SST data, on fields of remotely sensed SST yields biased fCO₂^sw values. This bias is reduced if the fCO₂^sw-SST relationships are derived using the same SST data that are used to create the SST fields. The fCO₂^sw fields found to best reproduce observed fCO₂^sw are used in combination with wind speed data from QuikSCAT to create weekly maps of the sea-air CO₂ flux in the Caribbean Sea in 2002. The region to the southwest of Cuba was a source of CO₂ to the atmosphere throughout 2002, and the region to the northeast was a sink during winter and spring and a source during summer and fall. The net uptake of CO₂ in the region was doubled when potential skin layer effects on fCO₂^sw were taken into account.

Ortner, P.B., S.R. Cummings, S.L. Smith, P. Lane, J. Lamkin, C. Yeung, and D. Jones. Abundance and diel migrations of demersal mesozooplankton and small reef fishes and their trophodynamic contribution to the coral reef ecosystem: A pilot study, pp. 27-28. In The Effects of Combined Sea Temperature, Light, and Carbon Dioxide on Coral Bleaching, Settlement, and Growth, J.C. Hendee (ed.). NOAA Research Special Report, Silver Spring, MD, 126 pp. (2004).

No abstract.

Pandya, R.E., D.R. Smith, M.K. Ramamurthy, P.J. Croft, M.J. Hayes, K.A. Murphy, J.D. Mcdonnell, R.M. Johnson, and H.A. Friedman. 11th American Meteorological Society Education Symposium. Bulletin of the American Meteorological Society, 85(3):425-430 (2004).

The 11th American Meteorological Society (AMS) Education Symposium was held from 13 to 15 January 2002 in Orlando, Florida, as part of the 82nd Annual Meeting of the AMS. The theme of the symposium was "creating opportunities in educational outreach in the atmospheric and related sciences." Drawing from traditional strengths in meteorology and numerous national recommendations, the presentations and posters of the symposium highlighted three opportunities for reform. These opportunities build on partnerships between diverse educational stakeholders, efforts to make science education more like scientific practice, and strategies that place the atmospheric sciences within a larger, multi-disciplinary context that includes oceanography, hydrology, and earth-system science.

Powell, M.D., J.D. Kepert, A. Boissonade, and P.J. Vickery. Uncertainty in hurricane winds: What do new measurements and simulations tell us about Hurricane Andrew? Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 522-523 (2004).

No abstract.

Powell, M.D., D. Bowman, D. Gilhousen, S.T. Murillo, N. Carrasco, and R. St. Fleur. Tropical cyclone winds at landfall: The ASOS-C-MAN Wind Exposure Documentation Project. Bulletin of the American Meteorological Society, 85(6):845-851 (2004).

Photographs describing the wind exposure at automatic weather stations susceptible to tropical cyclones are now available on web pages at the National Climatic Data Center and the National Data Buoy Center. Given the exposure for one of eight wind direction sectors, a user may estimate the aerodynamic roughness and correct mean wind measurements to an open-terrain exposure. The open-terrain exposure is consistent with the tropical cyclone advisories and forecasts issued by the National Weather Service, as well as building design wind load standards published by the American Society of Civil Engineers.

Rogers, R.F., M.L. Black, S.S. Chen, and R.A. Black. Evaluating microphysical parameterization schemes for use in hurricane environments. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 518-519 (2004).

No abstract.

Rogers, R.F., F.D. Marks, T.P. Marchok, and R. Tuleya. The development of a new validation technique for tropical cyclone rainfall. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 292-293 (2004).

No abstract.

Sabine, C.L., R.A. Feely, N. Gruber, R.M. Key, K. Lee, J.L. Bullister, R.H. Wanninkhof, C.S. Wong, D.W.R. Wallace, B. Tilbrook, F.J. Millero, T.-H. Peng, A. Kozyr, T. Ono, and A.F. Rios. The oceanic sink for anthropogenic CO₂. Science, 305(5682):367-371 (2004).

No abstract.

Saltzman, E.S., M. Aydin, W.J. De Bruyn, D.B. King, and S.A. Yvon-Lewis. Methyl bromide in pre-industrial air: Measurements from an Antarctic ice core. Journal of Geophysical Research, 109(D5):D05301, doi:10.1029/2003JD004157 (2004).

This paper presents the first ice core measurements of methyl bromide (CH₃Br). Samples from a shallow Antarctic ice core (Siple Dome, West Antarctica), ranging in mean gas dates from 1671 to 1942, had a mean CH₃Br mixing ratio of 5.8 ppt. These results extend the existing historical record derived from air and Antarctic firn air to about 350 years before present. Model simulations illustrate that the ice core results are consistent with estimates of the impact of anthropogenic activity (fumigation, combustion, and biomass burning) on the atmospheric CH₃Br burden, given the large current uncertainties in the modern atmospheric CH₃Br budget. A preindustrial scenario assuming no fumigation, no combustion, and a 75% reduction in biomass burning sources, yields a Southern Hemisphere mean mixing ratio of 5.8 ppt, in good agreement with the ice core results. There is a significant imbalance between the known CH₃Br sources and sinks in the modern atmospheric CH₃Br budget. The ice core data do not sufficiently constrain the model to determine how much of the "unknown source" was present in the preindustrial budget. The results do indicate that most of the southern hemispheric component of this "unknown source" is not anthropogenic.

Schneider, R., G.M. Barnes, and P.P. Dodge. Low-level kinematic, thermodynamic, and reflectivity fields of Hurricane Bonnie (1998) near landfall. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 572-573 (2004).

No abstract.

Stabenau, E.R., and R.G. Zika. Correlation of the absorption coefficient with a reduction in mean mass for dissolved organic matter in southwest Florida river plumes. Marine Chemistry, 89(1-4):55-67 (2004).

Results are presented from an investigation of the relationship between molecular mass distribution and optical properties for colored dissolved organic matter (CDOM); a complex assembly of organic macromolecules of marine and freshwater origin found throughout the surface ocean. Unique data are derived from the application of a new technique, a combination of a hydrophilic-lipophilic copolymer-based solid phase extraction (SPE) with electrospray ionization (ESI) continuous flowing ion trap mass spectrometry (cf-MS), for the direct determination of CDOM mass distribution. An evaluation of this copolymer-based extraction technique for the analysis of Suwannee River Natural Organic Matter (SRNOM) reference material revealed that the current method compares favorably with C₁₈ modified silica or XAD resin-based extraction methods reported in the literature when considering extraction efficiency or low extraction bias for CDOM. The mass distribution of CDOM in several freshwater to marine transition zones along coastal southwestern Florida has been determined with this technique. All rivers in the study region had a bimodal distribution of masses. A case study of the Caloosahatchee River outflow CDOM mass distribution data are presented as an example of the modification in mass distributions. The lower mass mode of the bimodal distribution was observed to have a relatively stable mean throughout the study region at 406�9 Da, while decreasing in concentration in a non-conservative manner with salinity. In contrast, the upper mass mode of the bimodal distribution was observed to have a variable mean, reaching 1408 Da in the least saline waters and decreasing by 174 Da through the transect toward higher salinity coastal waters. Coinciding with this reduction in mean mass for the upper distribution is a non-conservative reduction in concentration when compared with salinity. We define apparent organic carbon (AOC) as a function of the cf-MS determined total integrated area and use this value to determine concentration of the total extracted CDOM. Unique correlations between the CDOM fluorescence (350-nm excitation/450-nm emission) and the AOC for these coastal samples have been observed for each of three rivers in the study region. The steepest slope and highest correlation between optical and mass spectral properties are observed in rivers with strongly absorbing waters originating in the Florida Everglades and lowest in rivers draining clearer waters from widely variable and anthropogenic influenced regions. The trends in molecular mass distribution and corresponding optical properties support the theory that CDOM in coastal zones is environmentally processed material from terrestrial sources. Probable cause of the reduction in mean mass and suggestions for further investigation of sources and transformations of CDOM are discussed.

Stabenau, E.R., R.G. Zepp, E. Bartels, and R.G. Zika. Role of seagrass Thalassia testudinum as a source of chromophoric dissolved organic matter in coastal south Florida. Marine Ecology Progress Series, 282:59-72 (2004).

Seagrasses play a variety of important ecological roles in coastal ecosystems. Here we present evidence that seagrass detritus from the widespread species Thalassia testudinum is an important source of ocean color and a UV-protective substance in a low latitude coastal shelf region of the United States. The production and light-induced degradation of chromophoric (sunlight-absorbing) dissolved organic matter (CDOM) from T. testudinum was examined under field and controlled laboratory conditions to obtain data that could be used to estimate the contribution of seagrass-derived CDOM to the coastal pool. The laboratory studies measured the temperature dependence and photodegradation of the spectral (UV-visible, fluorescence) and molecular mass properties of CDOM produced during the degradation of T. testudinum detritus. The rate of CDOM production is temperature-dependent with rates doubling when temperature increases from 21.4 to 32.6°C. The magnitude of this increase is close to the widely observed Q₁₀ factor for microbial decomposition, indicating that the CDOM production was likely microbially mediated. The absorption coefficients and fluorescence of CDOM from T. testudinum decreased on exposure to solar UV radiation (UVR) and the wavelength dependence was determined for this photobleaching process.

Strong, A.E., G. Liu, J. Meyer, J.C. Hendee, and D. Sasko. Coral Reef Watch 2002. Bulletin of Marine Science, 75(2):259-268 (2004).

The National Oceanic and Atmospheric Administration's new Coral Reef Watch (CRW) program, led out of its National Environmental Satellite, Data, and Information Service (NESDIS) and Oceanic and Atmospheric Research (OAR) offices, will strive to fully utilize NOAA coral resources to monitor and predict changes in coral reef ecosystems worldwide. CRW inaugurated its first Coral Reef Early Warning System (CREWS) station in 2001 at "Rainbow Gardens," Lee Stocking Island, Great Exuma, Bahamas, with the installation of its first of 20 new in situ monitoring stations slated for many domestic reefs during this decade. A major objective is to discern the relationship between the magnitude and persistence of anomalously high sea surface temperatures in coral reef areas and coral reef bleaching and mortality. By coordinating both in situ point observations with the overview provided through satellite imagery, this program is designed to actively support coral reef managers and researchers through near real-time Web-access to coral reef environmental data and coral bleaching alerts.

Suvorov, A.M., V.N. Eremeev, V.N. Belokopytov, A.H. Khaliulin, E.A. Godin, A.V. Ingerov, D.R. Palmer, and S. Levitus. Digital atlas: Physical oceanography of the Black Sea. In Environmental Control Systems, V.N. Eremeev (ed.). National Academy of Science of Ukraine, Sevastopol, 125-129 (2004).

The digital atlas "Physical Oceanography of the Black Sea" resulted from a joint project between the Marine Hydrophysical Institute of the National Academy of Science of Ukraine and the NOAA/Atlantic Oceanographic and Meteorological Laboratory entitled "Rescue of Black Sea Hydrological Data for Regional Classification and Studies of Seasonal and Interannual Variability." Data from more than 104,000 Black Sea hydrographic stations were processed within the framework of the Project. From this database a climatic atlas of physical oceanographic variables was prepared. The atlas includes over 440 climatic maps. Both the atlas and database will be made available on a CD-ROM to the general user community.

Thacker, W.C., S.-K. Lee, and G.R. Halliwell. Assimilating 20 years of Atlantic XBT data into HYCOM: A first look. Ocean Modelling, 7(1-2):183-210 (2004).

Expendable bathythermographic (XBT) data for the years 1972-1991 have been assimilated into a Hybrid Coordinate Ocean Model (HYCOM) for the Atlantic Ocean. Climatological salinity profiles were combined with the observed temperature profiles to estimate companion potential-density profiles, which are used to determine the observation-based local structure of the model's hybrid layers. The model's density, temperature, and layer-interface-depth fields were corrected monthly via optimal interpolation. Preliminary results presented here show that the data have a major impact on the simulation, correcting model biases, and that the corrections persist between monthly assimilations.

Trinanes, J.A., and G.J. Goni. A web application for near real time distribution of tropical cyclone heat potential estimates. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 5-6 (2004).

No abstract.

Uhlhorn, E.W., and P.G. Black. Comparison of boundary layer profiles in Hurricanes Fabian and Isabel observed by GPS dropwindsonde and aircraft during CBLAST "stepped descents." Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 391-392 (2004).

No abstract.

Uhlhorn, E.W., and L.K. Shay. Analysis of upper-ocean thermodynamic observations forced by Hurricane Lili (2002). Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 619-620 (2004).

No abstract.

Wang, C. ENSO, Atlantic climate variability, and the Walker and Hadley circulations. In The Hadley Circulation: Present, Past, and Future, H.F. Diaz and R.S. Bradley (eds.). Kluwer Academic Publishers (ISBN 1-4020-2943-8), 173-202 (2004).

This chapter describes and discusses the Walker and Hadley circulations associated with the El Ni�o/Southern Oscillation (ENSO), the Atlantic "Ni�o", the tropical Atlantic meridional gradient variability, the Western Hemisphere warm pool (WHWP), and the North Atlantic Oscillation (NAO). During the warm phase of ENSO, the Pacific Walker circulation, the western Pacific Hadley circulation, and the Atlantic Hadley circulation are observed to be weakened, whereas the eastern Pacific Hadley circulation is strengthened. During the peak phase of the Atlantic Ni�o, the Atlantic Walker circulation weakens and extends eastward and the Atlantic Hadley circulation strengthens. The tropical Atlantic meridional gradient variability corresponds to a meridional circulation in which the air rises over the warm sea surface temperature (SST) anomaly region, flows toward the cold SST anomaly region aloft, sinks in the cold SST anomaly region, then crosses the equator toward the warm SST region in the lower troposphere. During periods when the NAO index is high, the atmospheric Ferrel and Hadley circulations are strengthened, consistent with surface westerly and easterly wind anomalies in the North Atlantic and in the middle to tropical Atlantic, respectively. The chapter also discusses a tropospheric bridge by the Walker/Hadley circulation that links the Pacific El Ni�o with warming of the tropical North Atlantic (TNA) and the WHWP.

Wang, C., and J. Picaut. Understanding ENSO physics: A review. In Earth's Climate: The Ocean-Atmosphere Interaction, C. Wang, S.-P. Xie, and J. Carton (eds.). American Geophysical Union, Geophysical Monograph Series, Volume 147 (ISBN 0-87590-412-2), 21-48 (2004).

Since the TOGA program and, in particular, the maintenance of its observing system in the tropical Pacific, significant progress has been made in the understanding of ENSO. ENSO has been viewed as a self-sustained and naturally oscillatory mode or a stable mode triggered by stochastic forcing. Whatever the case, El Ni�o involves Bjerknes' positive ocean-atmosphere feedback that culminates with warm SST anomalies in the equatorial eastern and central Pacific. After an El Ni�o reaches its mature phase, negative feedbacks are required to terminate the growth of warm SST anomalies. Four major negative feedbacks have been proposed: wave reflection at the ocean western boundary, a discharge process due to Sverdrup transport, a western Pacific wind-forced Kelvin wave of opposite sign, and anomalous zonal advection. These negative feedbacks may work in varying combinations to terminate El Ni�o, and reverse it into La Ni�a. The seasonal cycle can contribute to the irregularity and phase-locking of ENSO, and the intraseasonal variability can be a source of both ENSO's variability and irregularity. Tropical Pacific decadal-multidecadal variability and warming trends may modulate ENSO. Many mechanisms have been proposed to explain tropical Pacific decadal-multidecadal variability, and they are categorized by their tropical origins and tropical-extratropical connections. Mechanisms of tropical origins include stochastic forcing, interactions between the seasonal and interannual cycles, internal nonlinearity, asymmetry between El Ni�o and La Ni�a, and local ocean-atmosphere interaction, while those of tropical-extratropical connections involve oceanic bridges, wave propagation, and atmospheric bridges. Difficulties and uncertainties of studies on low-frequency variability and interpretation of warming trends, global warming, and ENSO are also discussed.

Wang, C., S.-P. Xie, and J.A. Carton. A Global survey of ocean-atmosphere interaction and climate variability. In Earth's Climate: The Ocean-Atmosphere Interaction, C. Wang, S.-P. Xie, and J.A. Carton (eds.). American Geophysical Union, Geophysical Monograph Series, Volume 147 (ISBN 0-87590-412-2), 1-19 (2004).

The interaction of the ocean and atmosphere plays an important role in shaping the climate and its variations. This chapter reviews the current state of knowledge of air-sea interaction and climate variations over the global ocean. The largest source of climate variability in the instrumental record is El Ni�o-Southern Oscillation (ENSO), which extends its reach globally through the ability of the atmosphere to bridge ocean basins. The growth of ENSO owes its existence to a positive ocean-atmosphere feedback mechanism (originally envisioned by J. Bjerknes) that involves the interaction of ocean dynamics, atmospheric convection, and winds in the equatorial Pacific. The Bjerknes feedback and the resultant equatorial zonal mode of climate variability are a common feature to all three tropical oceans despite differences in dimension, geometry and mean climate. In addition to this zonal mode, the tropics also support a meridional mode, whose growth is due to a thermodynamic feedback mechanism involving the interaction of the cross-equatorial gradient of properties such as sea surface temperature and displacements of the seasonal intertropical convergence zone. This meridional mode is observed in the tropical Atlantic, with some evidence of its existence in the Pacific and Indian Oceans. In the extratropics, in contrast, the sources of climate variability are more distributed. Much of climate variability may be explained by the presence of white noise due to synoptic weather disturbances whose impact on climate at longer timescales is due to the integrating effect of the ocean's ability to store and release heat. Still, there is some evidence of a more active role for the mid-latitude ocean in climate variability, especially near major ocean currents/fronts. Finally, various atmospheric and oceanic bridges that link different ocean basins are discussed, along with their implications for paleoclimate changes and the current global warming.

Wanninkhof, R.H., and R.A. Feely. Observing the global oceanic carbon cycle, pp. 12-28. In Annual Report on the State of the Ocean and the Ocean Observing System for Climate, D.M. Stanitski (ed.). NOAA Office of Climate Observation, Silver Spring, MD, 307 pp. (2004).

No abstract.

Wanninkhof, R.H., and F.J. Millero. Sea keepers network to study sea's role in absorbing greenhouse gases. Showboats International (January issue), 71 (2004).

No abstract.

Wanninkhof, R.H., K.F. Sullivan, and Z. Top. Air-sea gas transfer in the Southern Ocean. Journal of Geophysical Research, 109(C8):C08S19, doi:10.1029/2003JC001767 (2004).

Gas transfer velocities were determined in the Southern Ocean during the Southern Ocean Iron Fertilization experiment (SOFex) using the dual deliberate tracer technique. The decrease of the purposefully injected tracers, sulfur hexafluoride and helium-3, could be well described by gas exchange parameterizations with wind speed that satisfy global constraints based on bomb-¹⁴C uptake. The concentration decrease of tracers could be predicted slightly better with established relationships if gas transfer was modeled as a function of the cube rather than the square of the wind speed, particularly over a time interval with high and variable winds. However, both fits can model the concentration decrease within the uncertainty of the observations. This suggests that it will be singularly difficult to definitively determine if a quadratic or cubic dependence of gas exchange with wind is more appropriate based on deliberate tracer measurements. However, these results show that gas exchange rates in the Southern Ocean are not anomalous when compared with the rest of the ocean. Thus, this cannot account for discrepancy between observational and model-based estimates of uptake of CO₂ in the Southern Ocean. Using a high-quality wind speed field obtained from the QuikSCAT satellite Seawinds scatterometer and an established surface water pCO₂ climatology, the CO₂ uptake in the Southern Ocean (>34°S) is reassessed. The total uptake rates are similar to previous observation-based estimates, but the analysis shows that the uptake rate is sensitive to wind speed product used and the wind speed distribution.

Ward, B., R.H. Wanninkhof, P.J. Minnett, and M.J. Head. SkinDeEP: A profiling instrument for upper-decameter sea surface measurements. Journal of Atmospheric and Oceanic Technology, 21(2):207-222 (2004).

The Skin Depth Experimental Profiler (SkinDeEP) is an autonomous, self-contained, hydrodynamic instrument capable of making repeated, high-resolution profiles of temperature and conductivity within the ocean's upper decameter. Autonomous profiling operation is accomplished through SkinDeEP's ability to change its density: positive buoyancy is achieved by pumping air from inside the body of the profiler into an external, neoprene, inflatable sleeve; the instrument sinks when the sleeve is deflated by returning the air to the interior. The sensors are mounted some distance from the top endcap and data are recorded only during the ascending phase of the profile so as to minimize disruption of a naturally occurring scalar structure by the presence of the instrument. Temperature and conductivity are measured with resolutions in the submillimeter and millimeter ranges, respectively. Highly accurate and slower sensors are installed for calibration purposes. These data are used to study exchange processes at the air-sea interface and the structure of the ocean just below.

Ward, B., R.H. Wanninkhof, W.R. McGillis, A.T. Jessup, M.D. DeGrandpre, J.E. Hare, and J.B. Edson. Biases in the air-sea flux of CO₂ resulting from ocean surface temperature gradients. Journal of Geophysical Research, 109(C8):C08S08, doi:10.1029/2003JC001800 (2004).

The difference in the fugacities of CO₂ across the diffusive sublayer at the ocean surface is the driving force behind the air-sea flux of CO₂. Bulk seawater fugacity is normally measured several meters below the surface, while the fugacity at the water surface, assumed to be in equilibrium with the atmosphere, is measured several meters above the surface. Implied in these measurements is that the fugacity values are the same as those across the diffusive boundary layer. However, temperature gradients exist at the interface due to molecular transfer processes, resulting in a cool surface temperature, known as the skin effect. A warm layer from solar radiation can also result in a heterogeneous temperature profile within the upper few meters of the ocean. Here we describe measurements carried out during a 14-day study in the equatorial Pacific Ocean (GasEx-2001) aimed at estimating the gradients of CO₂ near the surface and resulting flux anomalies. The fugacity measurements were corrected for temperature effects using data from the ship's thermosalinograph, a high-resolution profiler (SkinDeEP), an infrared radiometer (CIRIMS), and several point measurements at different depths on various platforms. Results from SkinDeEP show that the largest cool skin and warm layer biases occur at low winds, with maximum biases of -4% and +4%, respectively. Time series ship data show an average CO₂ flux cool skin retardation of about 2%. Ship and drifter data show significant CO₂ flux enhancement due to the warm layer, with maximums occurring in the afternoon. Temperature measurements were compared to predictions based on available cool skin parameterizations to predict the skin-bulk temperature difference, along with a warm layer model.

White, S.R., and L.K. Shay. Modulations of surface wave energy over near-inertial time scales. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 621-622 (2004).

No abstract.

Willoughby, H.E., and M.E. Rahn. Parameteric representation of the primary hurricane vortex, Part I: Observations and evaluation of the Holland (1980) model. Monthly Weather Review, 132(12):3033-3048 (2004).

Although numerical models are essential to hurricane forecasting, many other applications require only statistical depiction of the wind distribution. In Holland's 1980 parametric profile, radius of maximum wind, maximum wind, and a measure of the profile width describe the radial variation of the axisymmetric wind. Variants of the Holland profile are used to predict insurance underwriting risk, ocean response, and storm-surge inundation. Since these calculations guide high-stakes financial and emergency management decisions, it is logical to test them against observations. The Hurricane Research Division's flight-level database archives observations were obtained by NOAA and U.S. Air Force Reserve aircraft. The data considered here are winds and geopotential heights observed during 606 lower- and midtropospheric flights into Atlantic and eastern Pacific tropical cyclones during 1977-2000. The 493 profiles that meet quality control criteria are seasonally geographically representative. Least squares fits of the Holland model to these data provide evaluation of the parameters' distributions and critical examination of the profile's realism. Individual fitted profiles differ from the observations in a consistent pattern. The areas of strong winds in the eyewall and of nearly calm winds at the vortex center are too wide. Beyond 2 or 3 times the eye radius, the wind decreases too rapidly with distance from the center. Although the average bias in fitted profiles is <1 m s^-1, the root-mean-square error is 4.2 m s^-1 (5.2 m s^-1 for independent data). Maximum winds estimated from the fitted Holland-profile height-wind relation average 2.5 m s^-1 too strong with an rms error of 6.5 m s^-1. The pattern of too strong wind spread over too much real estate exaggerates the occurrence of winds stronger than 50 m s^-1 by ~50%.

Willoughby, H.E., and M.E. Rahn. The climatology of hurricane wind profiles. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 264-265 (2004).

No abstract.

Wu, C.-C., P.-H. Lin, T.-C. Yeh, and S.D. Aberson. Dropsonde observations for typhoon surveillance near the Taiwan region (DOTSTAR): An overview. Preprints, 26th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 3-7, 2004. American Meteorological Society, Boston, 186-187 (2004).

No abstract.

Yvon-Lewis, S.A., D.B. King, R. Tokarczyk, K.D. Goodwin, E.S. Saltzman, and J.H. Butler. Methyl bromide and methyl chloride in the Southern Ocean. Journal of Geophysical Research, 109(C2):C02008, doi:10.1029/2003JC001809 (2004).

Air and water concentrations of methyl bromide (CH₃Br) and methyl chloride (CH₃Cl) were measured in the Southern Ocean (latitudes 45°S-67°S, longitudes 144°E-139°E) from late October through mid-December 2001. CH₃Br and CH₃Cl were undersaturated with mean saturation anomalies of -39�11% and -37�11% between 45°S and 65°S. The minimum degradation rate constants needed to maintain these saturation anomalies are consistent with the observed total degradation rate constants, suggesting that there is no significant production of these gases in this region. Near the Antarctic coast (south of 65°S), the saturation anomalies for both gases decreased to approximately -80%, although CFC-11 measurements suggest these extreme anomalies are associated with enhanced vertical mixing rather than degradation in the surface waters.

Zhang, J.-Z., C.J. Fischer, and P.B. Ortner. Potential availability of sedimentary phosphorus to sediment resuspension in Florida Bay. Global Biogeochemical Cycles, 18(4):GB4008, doi:10.1029/2004GB002255 (2004).

Several studies have suggested that phosphorus is a limiting nutrient for seagrass and phytoplankton growth in much of Florida Bay. In fact, soluble reactive phosphate concentrations in Florida Bay waters can be as low as a few nM. Sediments represent the largest phosphorus reservoir because Florida Bay sediments are dominated by carbonate, which has a strong capacity to retain phosphorus. The supply of phosphorus to the water column from sediment resuspension is potentially important in providing the nutrients required for phytoplankton production. Applying an improved sequential extraction technique to sediments collected from 40 geographically representative stations in Florida Bay, this study provides the first detailed spatial distribution of total sedimentary phosphorus (TSP) and its partitioning into five chemically distinguishable pools in the surface, fine-grained sediments of the bay. A strong gradient of decreasing TSP concentration was observed from the west (14.6 µmol g^-1) to east (1.2 µmol g^-1) across the central bay. The spatial pattern of TSP is consistent with distribution of both seagrass and phytoplankton that are limited by available phosphorus in Florida Bay. Among the five pools, the authigenic carbonate fluorapatite, biogenic apatite and CaCO3-bound phosphorus account for the largest fraction (45%) of TSP, of which inorganic phosphorus is the dominant form, and organic phosphorus accounts for about 30% in the western and north central regions and less than 10% in other areas of Florida Bay. The second largest pools are the refractory organic phosphorus (24% of TSP) and reductant-soluble inorganic phosphorus (19% of TSP). Readily exchangeable phosphorus accounts for 8% of TSP, of which organic phosphorus is 60%. Detrital apatite phosphorus of igneous or metamorphic origin represents the smallest fraction, only 5% of TSP. Spatial distribution of phosphorus and iron in sediments indicates that external sources of these two essential plant nutrients to Florida Bay are spatially separated with phosphorus introduced by west coast waters across the western margin of Florida Bay and iron from freshwater flow into the eastern region. **2003**

Aberson, S.D. Targeted observations to improve operational tropical cyclone track forecast guidance. Monthly Weather Review, 131(8):1613-1628 (2003).

Since 1997, the Tropical Prediction Center and the Hurricane Research Division have conducted operational synoptic surveillance missions with a Gulfstream IV-SP jet aircraft to improve numerical forecast guidance. Due to limited aircraft resources, optimal observing strategies for these missions must be developed. In the current study, the most rapidly growing modes are represented by areas of large forecast spread in the NCEP bred-vector ensemble forecasting system. The sampling strategy requires sampling of the entire target region with regularly spaced dropwindsonde observations. Three dynamical models were employed in testing the targeting and sampling strategies. With the assimilation into the numerical guidance of all the observations gathered during the surveillance missions, only the 12-h Geophysical Fluid Dynamics Laboratory Hurricane Model forecast showed statistically significant improvement. Assimilation of only the subset of data from the subjectively found fully sampled target regions produced a statistically significant reduction of the track forecast errors of up to 25% within the critical first two days of the forecast. This is comparable with the cumulative business-as-usual improvement expected over 18 yr.

Aberson, S.D., and C.R. Sampson. On the predictability of tropical cyclone tracks in the northwest Pacific basin. Monthly Weather Review, 131(7):1491-1497 (2003).

A new northwest Pacific climatology and persistence (CLIPER) model is derived with historical tropical cyclone tracks during the satellite and aircraft reconnaissance era (1970-1995). The new CLIPER extends the forecasts from three to five days and exhibits smaller forecast biases than the previous CLIPER, although forecast errors are comparable. The new model is based on more accurate historical tropical cyclone track data, and a simpler derivation of the regression equations, than is the old model. Nonlinear systems analysis shows that the predictability timescale in which the average errors increase by a factor e is just over 15 h, which is about the same as that calculated by similar methods near Australia and in the North Atlantic. This suggests that five-day tropical cyclone track forecasts may be beneficial, assuming small initial errors; therefore, a CLIPER model extended to five days is needed as a baseline to measure the forecast skill.

Ball, W.P., R.R. Dickerson, B.G. Doddridge, J.W. Stehr, T.L. Miller, D.L. Savoie, and T.P. Carsey. Bulk and size-segregated aerosol composition observed during INDOEX 1999: Overview of meteorology and continental impacts. Journal of Geophysical Research, 108(D10):8001, doi:10.1029/2002JD002467 (2003).

Bulk and size-segregated aerosol samples were collected from the NOAA R/V Ronald H. Brown as it cruised from Cape Town, South Africa, through the Indian Ocean and into the Bay of Bengal and Arabian Sea (February to April 1999; 33°S to 19°N). Throughout the Northern Hemisphere, aerosol loading was greater than in the Southern Hemisphere. Samples collected in air that had passed over India showed evidence of fossil fuel combustion, biomass burning, and eolian material, with elemental carbon (EC) dominating radiation absorption and the following relative contributions to the total mass of aerosol particles: ash 29%, nss-sulfate 22%, sea salt 15%, nitrate 9%, organic material 8%, ammonium 6%, and EC 5%. Careful examination of the coarse mode revealed substantial concentrations of nitrate, adequate to acidify sea salt aerosols north of the Intertropical Convergence Zone. Air that had passed over Arabia showed little evidence of biomass burning but had more acidity, mineral dust, and higher nitrate to sulfate ratios than air from India. High concentrations of mineral dust played a major role in radiation absorption; mean contributions to aerosol mass in Arabian air were: ash 38%, nss-sulfate 10%, sea salt 33%, nitrate 5%, organic material 4%, ammonium 1%, and EC 1%. From the ship we measured an average bulk aerosol concentration of 20 µg m^-3 in the marine boundary layer of the northern Indian Ocean.

Bentamy, A., K.B. Katsaros, A.M. Mestas-Nunez, W.M. Drennan, E.B. Forde, and H. Roquet. Satellite estimates of wind speed and latent heat flux over the global oceans. Journal of Climate, 16(4):637-656 (2003).

Surface fluxes of momentum, freshwater, and energy across the air-sea interface determine oceanic circulation and its variability at all time scales. The goal of this paper is to estimate and examine some ocean surface flux variables using satellite measurements. The remotely sensed data come from the European Remote Sensing (ERS) satellite scatterometer on ERS-2, NASA scatterometer (NSCAT), and several Defense Meteorological Satellite Program (DMSP) radiometers [Special Sensor Microwave Imager (SSM/I)] on board the satellites F10-F14. The sea surface temperature comes from daily analysis calculated from Advanced Very High Resolution Radiometer (AVHRR) measurements. This study focuses on the nine-month period (October 1996-June 1997) of the NSCAT mission. To ensure high quality of the merged surface parameter fields, comparisons between different satellite estimates for the same variable have been performed, and bias corrections have been applied so that they are compatible with each other. The satellite flux fields are compared to in situ observations from buoys and ships globally and in different regions of the ocean. It is found that the root-mean-square (rms) difference with weekly averaged wind speeds is less than 2.5 m s^-1 and the correlation coefficient is higher than 0.8. For weekly latent heat flux, the rms difference between satellite and buoys does not exceed 30 W m^-2. The comparisons with weekly ship latent heat flux estimates gives an rms difference approaching 40 W m^-2. Comparisons are also made between satellite fields and atmospheric analyses from the European Centre for Medium-Range Weather Forecasts (ECMWF) and reanalyses from the National Centers for Environmental Prediction-National Center for Atmospheric Research (NCEP-NCAR). The wind speeds and latent heat fluxes from these atmospheric analyses compare reasonably well with the satellite estimates. The main discrepancies are found in regions and seasons of large air-sea temperature difference and high wind speed, such as the Gulf Stream during the winter season.

Bitterman, D.S., R.H. Smith, W.D. Wilson, N. Melo, and T.N. Lee. Florida Bay shallow water surface drifter. Joint Conference on the Science and Restoration of the Greater Everglades and Florida Bay Ecosystem from Kissimmee to the Keys, Palm Harbor, FL, April 13-18, 2003. University of Florida Office of Conferences and Institutes, 56-58 (CD-ROM) (2003).

No abstract.

Black, M.L., F.D. Marks, R.F. Rogers, L.K. Shay, B.A. Albrecht, and H.E. Willoughby. The relationship between environmental wind shear and the distribution of vertical velocities and precipitation in the hurricane eyewall. Preprints, 31st Conference on Radar Meteorology, Seattle, WA, August 6-12, 2003. American Meteorological Society, Boston, 1016-1019 (2003).

No abstract.

Black, R.A., G.M. Heymsfield, and J. Hallett. Extra large particle images at 12 km in a hurricane eyewall: Evidence of high-altitude supercooled water? Geophysical Research Letters, 30(21):2124, doi:10.1029/2003GL017864 (2003).

The conventional wisdom about hurricanes suggests that updrafts are weak and supercooled water is scarce in the eyewall, and almost non-existent at temperatures colder than about -5°C (Black and Hallett, 1986). However, there is evidence that some hurricanes are different. Questions about the existence of high-altitude supercooled cloud water cannot be answered with only the instruments aboard the typical propeller-driven aircraft. During the summer of 1998, the NASA DC-8 aircraft made penetrations of the intensifying eyewall of Hurricane Bonnie at 12 km MSL, collecting the first truly high-altitude two-dimensional particle imagery in a hurricane. The similarity of the splash images in Hurricane Bonnie to those from raindrops obtained at higher temperatures in other hurricanes suggests that the large images obtained by the DC-8 were soft, low density graupel, rather than hard, high-density graupel particles or frozen raindrops. This implies that these particles grew to several millimeters in diameter at altitude, rather than simply advecting from lower, warmer altitudes. This growth in turn requires the presence of deeply supercooled cloud droplets. Thermal emission from supercooled water aloft increases the microwave brightness temperatures, giving a misleading impression that there is much less ice aloft than actually exists. The extra attenuation from the occasional presence of large graupel at these altitudes reduces the ability of microwave sensors to see precipitation at lower altitudes. Both of these effects impede efforts to accurately quantify condensate mass remotely from radiometric data such as that provided by the TRMM satellite.

Boebel, O., J.R.E. Lutjeharms, C. Schmid, W. Zenk, T. Rossby, and C. Barron. The Cape Cauldron: A regime of turbulent inter-ocean exchange. Deep-Sea Research, Part II, 50(1):57-86 (2003).

Combining in-situ Lagrangian intermediate depth velocity measurements from the KAPEX (Cape of Good Hope Experiments) float program with sea surface height data, this study reviews the inter-ocean exchange mechanisms around southern Africa. In the southeastern Cape Basin, a highly energetic field of coexisting anticyclonic and cyclonic eddies is documented. Agulhas rings of typically 200 km diameter are observed to merge, split, deform, and to reconnect to the Agulhas Retroflection. Concomitant, slightly smaller cyclones are observed to drift across the northwestward migration path of the Agulhas rings. These cyclones, with typical diameters of 120 km, are formed within the Cape Basin along the African shelf, inshore of the Agulhas Current, and in the subantarctic region south of Africa. The data suggest the annual formation of three to six long-lived Agulhas Rings that eventually cross 5°E longitude, while approximately twice the number of rings occur in the southeastern Cape Basin. Within this region, cyclones outnumber anticyclones by a factor of 3:2. Both cyclones and anticyclones extend through the upper thermocline into the intermediate depth layer. Mean drifts of anticyclones are 3.8 � 1.2 cm s^-1 to the northwest, while cyclones follow a west-southwestward route at 3.6 � 0.8 cm s^-1. Transport estimates suggest that the intermediate depth layer in the southeastern Cape Basin is primarily supplied from the east (approximately 9 Sv), with minor direct inflow from the Atlantic to the west and south. Cyclone/anticyclone interaction is surmised to result in vigorous stirring and mixing processes in the southeastern Cape Basin, which necessitates a review of the traditional concept of Indo-Atlantic inter-ocean exchange. We propose to limit the concept of "isolated Agulhas Rings embedded in a sluggish Benguela Drift" to the northwestern Cape Basin and beyond, while linking this regime to the Agulhas Retroflection proper through a zone of turbulent stirring and mixing in the southeastern Cape Basin, named for the first time the "Cape Cauldron" hereinafter.

Brenes, C.L., J.E. Coen, D.B. Chelton, D.B. Enfield, S. Leon, and D. Ballestero. Wind driven upwelling in the Gulf of Nicoya, Costa Rica. International Journal of Remote Sensing, 24(5):1127-1133 (2003).

Using satellite sensor data and information from local meteorological stations, a transient upwelling event in the Gulf of Nicoya, Costa Rica, has been observed during the period 6-8 March 1997 in coincidence with strong upwelling in the Gulf of Papagayo. Strong north-easterlies funneled through two mountain passes are responsible for this feature, observed intermittently between November and March.

Burkert, J., M.D. Andres-Hernandez, L. Reichert, J. Meyer-Arnek, B. Doddridge, R.R. Dickerson, J. Muhle, A. Zahn, T.P. Carsey, and J.P. Burrows. Trace gas and radical diurnal behavior in the marine boundary layer during INDOEX 1999. Journal of Geophysical Research, 108(D8):8000, doi:10.1029/2002JD002790 (2003).

Selected trace gas mixing ratios (i.e., peroxy radicals (RO*₂ = HO₂ + SIGMA-RO₂), nonmethane hydrocarbons (NMHCs), O₃, CO, HCHO, and NO) and photolysis rate coefficients of j(NO₂) and j(O(¹D)) were measured in the marine boundary layer (MBL) over the Indian Ocean. The measurements were performed during February, March, and April 1999 as a part of the Indian Ocean Experiment (INDOEX) on board the research vessel R/V Ronald H. Brown. During the campaign, air parcels having different origins and consequently variable compositions were encountered, but all air masses, including those heavily polluted with NMHCs and aerosols, were in the regime of rapid photochemical ozone destruction. The influence of aerosols on the photolysis frequencies was investigated by comparison of measurements and results from the radiative transfer model PHOTOST: the high optical depth (up to 0.6) and low single scattering albedo of the aerosol reduces the UV flux at the surface substantially downwind of India and Arabia causing, for instance, a reduction in j(O(¹D)) by up to 40%. The diurnal behavior of the trace gases and parameters in the MBL has been investigated by using a time-dependent zero-dimensional chemical model. Significant differences between the diurnal behavior of RO*₂ derived from the model and observed in measurements were identified. The measured HCHO concentrations differed from the model results and are best explained by some missing chemistry involving low amounts of Cl. Other possible processes describing these two effects are presented and discussed.

Burpee, R.W. Characteristics of African easterly waves. In A Half Century of Progress in Meteorology: A Tribute to Richard Reed, R.H. Johnson and R.A. Houze, Jr. (eds.). American Meteorological Society, Meteorological Monograph, Volume 31, Number 53 (ISBN 1-878220-58-6), 91-108 (2003).

No abstract.

Chung, S.-N., K. Lee, R.A. Feely, C.L. Sabine, F.J. Millero, R.H. Wanninkhof, J.L. Bullister, R.M. Key, and T.-H. Peng. Calcium carbonate budget in the Atlantic Ocean based on water column inorganic carbon chemistry. Global Biogeochemical Cycles, 17(4):1093, doi:10.1029/2002GB002001 (2003).

Recent independent lines of evidence suggest that the dissolution of calcium carbonate (CaCO₃) particles is substantial in the upper ocean above the calcite 100% saturation horizon. This shallow-water dissolution of carbonate particles is in contrast with the current paradigm of the conservative nature of pelagic CaCO₃ at shallow water depths. Here we use more than 20,000 sets of carbon measurements in conjunction with CFC and ¹⁴C data from the WOCE/JGOFS/OACES global CO₂ survey to estimate in-situ dissolution rates of CaCO₃ in the Atlantic Ocean. A dissolution rate is estimated from changes in alkalinity as a parcel of water ages along an isopycnal surface. The in-situ CaCO₃ dissolution increases rapidly at the aragonite 100% saturation horizon. Estimated dissolution rates north of 40°N are generally higher than the rates to the south, which is partly attributable to the production of exported CaCO₃ being higher in the North Atlantic than in the South Atlantic. As more CaCO₃ particles move down the water column, more particles are available for in-situ dissolution. The total water column CaCO₃ dissolution rate in the Atlantic Ocean is determined on an annual basis by integrating estimated dissolution rates throughout the entire water column and correcting for alkalinity input of approximately 5.6 x 10¹² mol C yr^-1 from CaCO₃-rich sediments. The resulting water column dissolution rate of CaCO₃ for the Atlantic Ocean is approximately 11.1 x 10¹² mol C yr^-1. This corresponds to about 31% of a recent estimate (35.8 x 10¹² mol C yr^-1) of net CaCO₃ production by Lee (2001) for the same area. Our calculation using a large amount of high-quality water column alkalinity data provides the first basin-scale estimate of the CaCO₃ budget for the Atlantic Ocean.

Cione, J.J., and E.W. Uhlhorn. Sea surface temperature variability in hurricanes: Implications with respect to intensity change. Monthly Weather Review, 131(8):1783-1796 (2003).

Scientists at NOAA's Hurricane Research Division recently analyzed the inner-core upper-ocean environment for 23 Atlantic, Gulf of Mexico, and Caribbean hurricanes between 1975 and 2002. The interstorm variability of sea surface temperature (SST) change between the hurricane inner-core environment and the ambient ocean environment ahead of the storm is documented using airborne expendable bathythermograph (AXBT) observations and buoy-derived archived SST data. The authors demonstrate that differences between inner-core and ambient SST are much less than poststorm, "cold wake" SST reductions typically observed (i.e., 0-2°C versus 4-5°C). These findings help define a realistic parameter space for storm-induced SST change within the important high-wind, inner-core hurricane environment. Results from a recent observational study yielded estimates of upper-ocean heat content, upper-ocean energy extracted by the storm, and upper-ocean energy utilization for a wide range of tropical systems. Results from this analysis show that, under most circumstances, the energy available to the tropical cyclone is at least an order of magnitude greater than the energy extracted by the storm. This study also highlights the significant impact that changes in inner-core SST have on the magnitude of air-sea fluxes under high-wind conditions. Results from this study illustrate that relatively modest changes in inner-core SST (order 1°C) can effectively alter maximum total enthalpy (sensible plus latent heat) flux by 40% or more. The magnitude of SST change (ambient minus inner core) was statistically linked to subsequent changes in storm intensity for the 23 hurricanes included in this research. These findings suggest a relationship between reduced inner-core SST cooling (i.e., increased inner-core surface enthalpy flux) and tropical cyclone intensification. Similar results were not found when changes in storm intensity were compared with ambient SST or upper-ocean heat content conditions ahead of the storm. Under certain circumstances, the variability associated with inner-core SST change appears to be an important factor directly linked to the intensity change process.

Crusius, J., and R.H. Wanninkhof. Gas transfer velocities measured at low wind speed over a lake. Limnology and Oceanography, 48(3):1010-1017 (2003).

The relationship between gas transfer velocity and wind speed was evaluated at low wind speeds by quantifying the rate of evasion of the deliberate tracer, SF₆, from a small oligotrophic lake. Several possible relationships between gas transfer velocity and low wind speed were evaluated by using 1-min-averaged wind speeds as a measure of the instantaneous wind speed values. Gas transfer velocities in this data set can be estimated virtually equally well by assuming any of three widely used relationships between k₆₀₀ and winds referenced to 10-m height, U₁₀: (1) a bilinear dependence with a break in the slope at ~3.7 m s^-1, which resulted in the best fit; (2) a power dependence; and (3) a constant transfer velocity for U₁₀ < ~3.7 m s^-1, with a linear dependence on wind speed at higher wind speeds. The lack of a unique relationship between transfer velocity and wind speed at low wind speeds suggests that other processes, such as convective cooling, contribute significantly to gas exchange when the wind speeds are low. All three proposed relationships clearly show a strong dependence on wind for winds >3.7 m s^-1 which, coupled with the typical variability in instantaneous wind speeds observed in the field, leads to average transfer velocity estimates that are higher than those predicted for steady wind trends. The transfer velocities predicted by the bilinear steady wind relationship for U₁₀ < ~3.7 m s^-1 are virtually identical to the theoretical predictions for transfer across a smooth surface.

Darrow, B.P., J.J. Walsh, G.A. Vargo, R.T. Masserini, K.A. Fanning, and J.-Z. Zhang. A simulation study of the growth of benthic microalgae following the decline of a surface phytoplankton bloom. Continental Shelf Research, 23(14-15):1265-1283 (2003).

The West Florida continental shelf is an oligotrophic system for most of the year. An episodic chlorophyll plume has previously been observed in satellite imagery on the northern portion of the shelf during the spring months. The fate of the plume upon its decline in the late spring and early summer is unknown. Decreased chlorophyll levels and sustained nutrient stocks may be explained by sediment/water-column interactions, including the presence of benthic microalgae. A one-dimensional model, consisting of 16 state variables, is constructed to simulate the decline of a surface chlorophyll bloom in the northeastern Gulf of Mexico as measured during the Florida Shelf Lagrangian Experiment (FSLE). Results from a baseline simulation of two FSLE studies suggest that remineralized nutrients from the declining bloom are taken up by heterotrophic bacteria in the water-column and by benthic microalgae in the sediments. Perturbation experiments imply that low light levels, due to increased CDOM, do not have significant effects on the benthic microfloral community at mid-shelf locations.

Dunion, J.P., C.W. Landsea, S.H. Houston, and M.D. Powell. A reanalysis of the surface winds for Hurricane Donna of 1960. Monthly Weather Review, 131(9):1992-2011 (2003).

Hurricane Donna, the only major hurricane to strike the United States during the 1960 Atlantic hurricane season, passed over the middle Florida Keys near Sombrero Key before making landfall southeast of Naples, near Goodland, Florida, on 10 September at approximately 1600 UTC. This study makes detailed retrospective surface wind analyses of Hurricane Donna utilizing the National Oceanic and Atmospheric Administration (NOAA) Hurricane Research Division's (HRD) H*Wind surface wind analysis system. Analyses were produced at intervals of 6 h between 1800 UTC 9 September and 1200 UTC 11 September 1960 while the hurricane was close to and over Florida. These analyses depict the storm track as well as the distribution and extent of tropical storm force, 50 kt (25.7 m s^-1), and the hurricane-force wind radii throughout this time period and include new methodologies for adjusting aircraft flight-level data to the surface in the tropical cyclone core environment. Algorithms were developed to account for the effects of eyewall tilt and the warm core structure typical of tropical cyclones. Additional methods were developed using global positioning system (GPS) dropwindsondes (sondes) to more accurately adjust boundary layer winds to equivalent surface winds. The Kaplan-DeMaria Inland Wind Decay Model was also used for the first time to adjust landfall data being input into the H*Wind system. These data were used to generate low-weighted background fields that helped generate postlandfall wind field analyses of Hurricane Donna. Finally, swaths of peak winds, duration of hurricane- and major hurricane-force winds, and wind steadiness were produced to facilitate damage assessment. The information provided by these objective analyses is significantly more detailed than the more limited descriptions of peak winds, storm position, and minimum central pressure available in the National Hurricane Center's (NHC) hurricane database archive (HURDAT).

Esenkov, O.E., D.B. Olson, and R. Bleck. A study of the circulation and salinity budget of the Arabian Sea with an isopycnic coordinate ocean model. Deep-Sea Research, Part II, 50(12-13):2091-2110 (2003).

The evolution of surface circulation and salinity budget are studied with the open-boundary version of the Miami Isopycnic Coordinate Ocean Model (MICOM) that uses a global MICOM simulation as a boundary condition. Under climatological wind and thermodynamic forcing, the model develops solutions that are in good agreement with the climatologically forced global MICOM results and with observations. When the observed winds force the model, interannual variability of the surface fields increases significantly. However, coalescence of the two large eddies off Somalia in the end of the summer monsoon suggested in earlier observations does not occur in the model. To identify what processes facilitate or restrict the merger, a series of experiments was performed with modified model parameters and forcing fields. The eddies coalesced when half-slip, rather than no-slip, boundary conditions were used. In this case, less positive vorticity was produced at the coast, resulting in reduced blocking effect on the propagation of the southern eddy. The Socotra Island, which is submerged in the standard model, hinders a northward movement of the Great Whirl, leading to a stronger interaction between the eddies, which results in their subsequent merging. A more realistic coalescence occurs in an experiment where winds are held constant after reaching the peak summer value. Freshwater fluxes from the east and south are important for the salinity budget in the Arabian Sea, where evaporation exceeds precipitation. The only significant cross-equatorial transport of low-salinity water occurs in the upper 400 m in the model. Most of this water is advected below the surface mixed layer at the western boundary. The strongest interaction between the mixed layer and the oceanic interior occurs during the summer in the coastal upwelling regions off Somalia. Almost half of all upwelled water comes from depths between 100 and 200 m, thus signifying the importance of mid-depth circulation and water mass distribution for the surface processes.

Fox-Norse, V., and J.R. Proni. Innovative applications of advanced ocean acoustics, optics, and other supporting technologies for marine water quality monitoring and assessment: New national guidance tools to address ongoing and emerging coastal management issues. Proceedings, 13th Biennial Coastal Zone Conference, Baltimore, MD, July 13-17, 2003. NOAA Coastal Services Center, CD-ROM, 20322-CD (2003).

No abstract.

Fram, M.S., B.A. Bergamaschi, K.D. Goodwin, R. Fujii, and J.F. Clark. Processes affecting the trihalomethane concentrations associated with the third injection, storage, and recovery test at Lancaster, Antelope Valley, California, March 1998 through April 1999. U.S. Geological Survey, Water-Resources Investigations Report 03-4062, 72 pp. (2003).

The formation and fate of trihalomethanes (THM) during the third injection, storage, and recovery test at Lancaster, Antelope Valley, California, were investigated as part of a program to assess the long-term feasibility of using injection, storage, and recovery as a water-supply method and as a way to reduce water-level declines and land-subsidence in the Antelope Valley. The program was conducted by the U.S. Geological Survey in cooperation with the Los Angeles County Department of Public Works and the Antelope Valley-East Kern Water Agency. The water used for injection, storage, and recovery must be disinfected before injection and thus contains THMs and other disinfection byproducts. THMs (chloroform, CHCl₃, bromodichloromethane, CHCl₂Br, dibromochloromethane, CHClBr₂, and bromoform, CHBr₃) are formed by reaction between natural dissolved organic carbon that is present in water and chlorine that is added during the disinfection step of the drinking water treatment process. THMs are carcinogenic compounds, and their concentrations in drinking water are regulated by the U.S. Environmental Protection Agency. During previous cycles of the Lancaster program, extracted water still contained measurable concentrations of THMs long after continuous pumping had extracted a greater volume of water than had been injected. This raised concerns about the potential long-term effect of injection, storage, and recovery cycles on ground-water quality in Antelope Valley aquifers. The primary objectives of this investigation were to determine (1) what controlled continued THM formation in the aquifer after injection, (2) what caused the persistence of THMs in the extracted water, even after long periods of pumping, (3) what controlled the decrease of THM concentrations during the extraction period, and (4) the potential for natural attenuation of THMs in the aquifer.

Franca, C., I. Wainer, A.R. de Mesquita, and G.J. Goni. Planetary equatorial trapped waves in the Atlantic Ocean from TOPEX/Poseidon altimetry. In Interhemispheric Water Exchange in the Atlantic Ocean, G.J. Goni and P. Malanotte-Rizzoli (eds.). Elsevier Oceanography Series, 68 (ISBN 0444512675), 213-232 (2003).

Planetary equatorial waves are important mechanisms for the adjustment of the tropical oceans. The identification and role of planetary equatorial waves in the tropical Atlantic is investigated by taking advantage of unprecedented accuracy, coverage and resolution of the TOPEX/POSEIDON altimeter data, from 1992 to 1999. This is accomplished by projecting the sea level height anomalies, obtained from the altimetry for the tropical Atlantic basin onto the linear equatorial meridional waves, first baroclinic mode. Results presented here show the existence of equatorial Kelvin and Rossby modes, as well as their significant reflection off the African coast.

Franklin, J.L., M.L. Black, and K. Valde. GPS dropwindsonde wind profiles in hurricanes and their operational implications. Weather and Forecasting, 18(1):32-44 (2003).

The recent development of the global positioning system (GPS) dropwindsonde has allowed the wind and thermodynamic structure of the hurricane eyewall to be documented with unprecedented accuracy and resolution. In an attempt to assist operational hurricane forecasters in their duties, dropwindsonde data have been used in this study to document, for the first time, the mean vertical profile of wind speed in the hurricane inner core from the surface to the 700-hPa level, the level typically flown by reconnaissance aircraft. The dropwindsonde-derived mean eyewall wind profile is characterized by a broad maximum centered 500 m above the surface. In the frictional boundary layer below this broad maximum, the wind decreases nearly linearly with the logarithm of the altitude. Above the maximum, the winds decrease because of the hurricane's warm core. These two effects combine to give a surface wind that is, on average, about 90% of the 700-hPa value. The dropwindsonde observations largely confirm recent operational practices at the National Hurricane Center for the interpretation of flight-level data. Hurricane wind profiles outside of the eyewall region are characterized by a higher level of maximum wind, near 1 km, and a more constant wind speed between 700 hPa and the top of the boundary layer. Two factors that likely affect the eyewall profile structure are wind speed and vertical motion. A minimum in surface wind adjustment factor (i.e., relatively low surface wind speeds) was found when the wind near the top of the boundary layer was between 40 and 60 m s^-1. At higher wind speeds, the fraction of the boundary layer wind speed found at the surface increased, contrary to expectation. Low-level downdrafts and enhanced vertical motion generally were also associated with higher relative surface winds. These results may be of interest to engineers concerned with building codes, to emergency managers who may be tempted to use high-rise buildings as a "refuge of last resort" in coastal areas, and to those people on locally elevated terrain. The top of a 25-story coastal high-rise in the hurricane eyewall will experience a mean wind that is about 17% higher (or one SaffirSimpson hurricane-scale category) than the surface or advisory value. For this reason, residents who must take refuge in coastal high-rises should generally do so at the lowest levels necessary to avoid storm surge.

Garraffo, Z.D., W.E. Johns, E.P. Chassignet, and G.J. Goni. North Brazil Current rings and transport of southern waters in a high resolution numerical simulation of the North Atlantic. In Interhemispheric Water Exchange in the Atlantic Ocean, G.J. Goni and P. Malanotte-Rizzoli (eds.). Elsevier Oceanography Series, 68 (ISBN 0444512675), 375-409 (2003).

Output from a very high resolution (1/12 deg.) North Atlantic simulation with the Miami Isopycnic Coordinate Ocean Model (MICOM) is analyzed in a region of the Tropical Atlantic characterized by the presence of the North Brazil Current (NBC) retroflection and North Brazil Current rings. The model mean and seasonal circulations present a good qualitative agreement with observations. Quantitatively, the modeled NBC in summer and fall does not completely retroflect into the North Equatorial Counter Current, and the model upper 100 m NBC is more intense than the observed values by 3-4 Sv. The modeled NBC generates a variety of rings, which we classify as "shallow," "intermediate," "deep," and "subsurface." An average of 8.3 rings of all types are generated per year, of which 6 are surface intensified, in good agreement with altimetry (5.7 rings per year, Goni and Johns, 2001). The transport of southern origin water by the rings was estimated using two methods. First, the transport was computed kinematically from the rings' volume, resulting in an average transport of 6.6 Sv. Second, an estimation of southern water transport based on an explicit calculation of water mass content was done, resulting in an average transport of 7.5 Sv. The rings' contribution represents ~40% of the total meridional transport from the surface to the intermediate water layers. Possible mechanisms operating in the model ring generation are briefly discussed.

Garrison, L.P., S.L. Swartz, A. Martinez, C. Burks, and S.J. Stamates. A marine mammal assessment survey of the southeast U.S. continental shelf: February-April 2002. NOAA Technical Memorandum, NMFS SEFSC-492 (PB2003-103332), 70 pp. (2003).

To augment information on the winter spatial distribution and abundance of marine mammals in the mid-Atlantic region, the NOAA Fisheries SEFSC conducted a population assessment survey covering continental shelf and inner slope waters from northern Florida to Delaware Bay during February-April 2002 that included both visual and passive hydroacoustic surveys. The survey was conducted under an agency agreement between NOAA Fisheries and the U.S. Navy that recognizes the need of both agencies for accurate information on the abundance and seasonal spatial distribution of marine mammal stocks. The primary objectives of the winter 2002 survey were to: (1) conduct a visual line transect survey of the mid-Atlantic continental shelf and inner slope waters from northern Florida to Delaware Bay to determine the abundance and spatial distribution of marine mammals; (2) continue the development and application of passive hydroacoustic methods to detect marine mammals and augment visual observations; and (3) opportunistically collect skin biopsy samples with particular focus on Atlantic bottlenose dolphin.

Garzoli, S.L., and J. Servain. CLIVAR workshop on tropical Atlantic variability. Geophysical Research Letters, 30(5):8001, doi:10.1029/2002GL016823 (2003).

No abstract.

Garzoli, S.L., A. Ffield, and Q. Yao. North Brazil Current rings and the variability in the latitude of the retroflection. In Interhemispheric Water Exchange in the Atlantic Ocean, G.J. Goni and P. Malanotte-Rizzoli (eds.). Elsevier Oceanography Series, 68 (ISBN 0444512675), 357-373 (2003).

An array of 14 inverted echo sounders (IES) were deployed as part of the North Brazil Current Rings (NBCR) experiment to study the dynamics of the ocean in the region. Synoptic maps of dynamic height were produced from the data collected with the IES. After validating these maps with hydrographic data collected during the four NBCR cruises, they were analyzed to determine the variability of the latitude of retroflection of the North Brazil Current (NBC) and the number of rings shed during this process. Results from this analysis indicate that there is no obvious seasonality in the variability of the latitude of penetration of the NBC and, with the exception of one event, each time that the NBC reaches its northward position a ring is shed at the retroflection. A total of 11 rings were shed during the period of the observations November 1998 to June 2000. The mean diameter of the rings was estimated to be approximately 390 km, and the mean speed of propagation 12.4 km/day. The rings transported an average of 8 Sv (1 Sv = 10⁶ m³ s^-1) of water and 0.54 PW of heat per year. These estimates are much larger than previous results, both in the number of rings shed per year and in the contribution of the rings to the inter-hemispheric exchange of mass and heat.

Gedzelman, S., E. Hindman, X. Zhang, J. Lawrence, J.F. Gamache, M.L. Black, R.A. Black, J.P. Dunion, and H.E. Willoughby. Probing hurricanes with stable isotopes of rain and water vapor. Monthly Weather Review, 131(6):1112-1127 (2003).

Rain and water vapor were collected during flights in Hurricanes Olivia (1994), Opal (1995), Marilyn (1995), and Hortense (1995) and analyzed for their stable isotopic concentrations, or ratios, H₂¹⁸O:H₂O and HDO:H₂O. The spatial patterns and temporal changes of isotope ratios reflect details of a hurricane's structure, evolution, microphysics, and water budget. At all flight levels over the sea (850-475 hPa) the lowest isotope ratios occur in or near regions of stratiform rains between about 50 and 250 km from the eye. Isotope ratios are higher in the eyewall and were particularly high in the crescent-shaped eyewall of Hurricane Opal at a time when no rain was falling over a large area near the storm center. In Hurricane Olivia, isotope ratios decreased from 24 to 25 September after vertical and radial circulation weakened. A two-layer isotope model of a radially symmetric hurricane simulates these features. The low isotope ratios are caused by fractionation in extensive, thick, precipitating clouds with predominantly convergent low-level flow accompanied by removal of heavy isotopes by falling raindrops. Evaporation and isotope equilibration of sea spray increase isotope ratios of the ambient vapor and produce a deuterium excess or enrichment of D relative to ¹⁸O that increases with decreasing relative humidity and increasing wind speed. Model results show that sea spray supplies the eyewall with up to 50% of its water vapor and is largely responsible for its high isotope ratios.

Goni, G.J., and W.E. Johns. Synoptic study of warm rings in the North Brazil Current retroflection region using satellite altimetry. In Interhemispheric Water Exchange in the Atlantic Ocean, G.J. Goni and P. Malanotte-Rizzoli (eds.). Elsevier Oceanography Series, 68 (ISBN 0444512675), 335-356 (2003).

Ten years of altimeter data are used in conjunction with temperature and salinity data within a two-layer reduced gravity approximation to investigate the shedding and translation of North Brazil Current rings. Space-time diagrams of sea height anomalies and residues along the altimeter groundtracks show large seasonal and interannual variability. Results presented here confirm previous estimates that indicate a shedding rate of 3 to 7 rings per year with no marked seasonal variability but with very strong year-to-year variability. Additionally, eddies not shed by the retroflection travel through the region as well. Most of the rings pass very near of Barbados, affecting the environment in the region, of which seven rings during the study period are seen to enter into the Caribbean Sea. A link is found in this study between long-term surface temperature changes in the tropical Atlantic and the number of rings shed at the NBC retroflection, where periods of time with warmer surface temperatures are associated to a higher number of rings shed.

Goni, G.J., and J.A. Trinanes. Ocean thermal structure monitoring could aid in the intensity forecast of tropical cyclones. EOS, Transactions, American Geophysical Union, 84(51):573-578 (2003).

Accurate prediction of the track and intensity of tropical cyclones is highly important for planning the evacuation of densely populated coastal areas and for impact assessment. Though forecasts of Atlantic hurricane tracks have improved greatly during recent years, large errors in intensity forecasts still remain. Dynamical and statistical models are currently being used, with a different range of success, to predict the location of tropical cyclone intensity changes. Statistical prediction models attempt to quantify the relationship between tropical cyclone intensification and variables that can be estimated or observed in real time. Some examples of these variables, referred to as predictors, are initial maximum wind speed, wind shear, latitude of the tropical cyclones, and sea surface temperature (SST). The subsurface ocean thermal structure is also being considered as a predictor among several other thermodynamic variables that could further enhance our knowledge of the role of the ocean in tropical cyclone intensification. Results from a methodology for estimating the oceanic tropical cyclone heat potential (TCHP) are now being used to aid in the investigation of intensity changes in tropical cyclones, and to improve current models for operational prediction. Global estimates of this parameter are posted daily at www.aoml.noaa.gov/phod/cyclone/data.

Goni, G.J., P.G. Black, and J.A. Trinanes. Using satellite altimetry to identify regions of hurricane intensification. AVISO Newsletter, 9:19-20 (2003).

No abstract.

Halliwell, G.R., R.H. Weisberg, and D.A. Mayer. A synthetic float analysis of upper-limb meridional overturning circulation interior ocean pathways in the tropical/subtropical Atlantic. In Interhemispheric Water Exchange in the Atlantic Ocean, G.J. Goni and P. Malanotte-Rizzoli (eds.). Elsevier Oceanography Series, 68 (ISBN 0444512675), 93-136 (2003).

Synthetic floats are released in an ocean general circulation model to study fluid pathways followed by the upper limb of the meridional overturning circulation from the subtropical South Atlantic to the subtropical North Atlantic. The floats are designed to track this fundamentally three-dimensional, non-isentropic flow while sampling water properties and all terms of the equation governing the vertical component of relative vorticity. The low-resolution ocean simulations demonstrate how upper-limb flow navigates the complex, time-dependent system of wind-driven gyres. Pathways that extend into the interior North Atlantic before entering the Caribbean Sea are emphasized over the more direct western boundary route. A large number of floats are released in the southern hemisphere to verify the importance of such interior pathways in the model and document key events that occur along them. Upper limb water first approaches the equator in a modified inertial western boundary layer. Equatorial processes (visco-inertial boundary layer dynamics, upwelling, heating) are necessary to reset water properties and permit fluid to permanently cross the equator, typically requiring eastward retroflection into the EUC. After upwelling at the equator, fluid that does not advect northward or southward into the interior returns to the western boundary and turns northward in a frictional western boundary layer. The generation of negative relative vorticity by planetary vorticity advection can break the boundary layer constraint and permit retroflection into the NECC near 5°N from late spring through fall. Once in the interior, this fluid advects northward into the southern subtropical gyre in a flow governed by Ekman dynamics. There the fluid subducts and advects southwestward to enter the Caribbean Sea under the influence of layered thermocline dynamics. The importance of interior pathways is confirmed, although we note that fluid parcels generally take complex paths and frequently make multiple attempts to enter the northern hemisphere or multiple treks around gyres.

Hendee, J.C., and R. Berkelmans. Expert system generated coral bleaching alerts for Myrmidon and Agincourt reefs, Great Barrier Reef, Australia. Proceedings, 9th International Coral Reef Symposium, Bali, Indonesia, October 23-27, 2000. International Society for Coral Reefs, 1099-1104 (2003).

An expert system, termed the Coral Reef Early Warning System (CREWS), was employed at NOAA's Atlantic Oceanographic and Meteorological Laboratory (AOML) in Miami, Florida, USA, to provide interpretations of combinations of near real-time meteorological and oceanographic data, thought to be conducive to coral bleaching. These data were collected via HF radio from automatic weather stations operated by the Australian Institute of Marine Science at Myrmidon and Agincourt Reefs in the central Great Barrier Reef. At Myrmidon Reef, CREWS was useful in "predicting" coral bleaching during the end of January and early February 2000. This prediction was verified in the field with observations of low level bleaching for a few species of Acropora (especially Acropora gemmifera and A. digitifera) on the reef flat at Myrmidon Reef. In February 2000, alerts were produced and sent for Agincourt Reef, 330 km north of Myrmidon Reef, but field observations showed that bleaching did not occur. These results suggest that CREWS may be fine-tuned to predict bleaching in thermally sensitive species or genera at individual locations.

Houston, S.H., and M.D. Powell. Surface wind fields for Florida Bay hurricanes. Journal of Coastal Research, 19(3):503-513 (2003).

The surface wind fields of several tropical cyclones which impacted Florida Bay and the surrounding coastal areas were reconstructed by the Hurricane Research Division (HRD) of the national Oceanographic and Atmospheric Administration. These cyclones provided the forcing for significant changes in water levels, waves, and currents, resulting in sediment transport, deposition, and other physical processes affecting the Bay. In addition, tropical cyclones had direct and indirect effects on plant and animal life in the Bay and the surrounding coastal areas, such as the Florida Keys and Everglades. The HRD wind fields are being made available in gridded form for use in hindcasts, which may help researchers to estimate the potential impacts of future tropical cyclones on the south Florida ecosystem, especially in relation to Florida Bay. The tropical cyclones investigated represent vastly different scenarios for the type of events that might be expected over extreme south Florida. The reconstructed storms range in intensity from Tropical Storm Gordon of 1994 to the Labor Day Hurricane of 1935 (the United States' most intense hurricane at landfall). This paper summarizes the methods used to reconstruct tropical cyclone surface wind fields and provides examples of their circulation features and wind swaths. Comparisons of winds to observed damage are also presented for three major hurricanes. The wind fields for all of these tropical cyclones are being made available to researchers as graphical products and gridded data sets on a Web site maintained by HRD (www.aoml.noaa.gov/hrd).

Jiang, M.-S., F. Chai, R.C. Dugdale, F.P. Wilkerson, T.-H. Peng, and R.T. Barber. A nitrate and silicate budget in the equatorial Pacific Ocean: A coupled physical-biological model study. Deep-Sea Research, Part II, 50(22-26):2971-2996 (2003).

A coupled physical-biological model was developed to simulate the low-silicate, high-nitrate, and low-chlorophyll (LSHNLC) conditions in the equatorial Pacific Ocean and used to compute a detailed budget in the Wyrtki box (5°N-5°S, 180-90°W) for the major sources and cycling of nitrogen and silicon in the equatorial Pacific. With the incorporation of biogenic silicon dissolution, NH₄ regeneration from organic nitrogen and nitrification of ammonia in the model, we show that silicon recycling in the upper ocean is less efficient than nitrogen. As the major source of nutrients to the equatorial Pacific, the Equatorial Undercurrent provides slightly less Si(OH)₄ than NO₃ to the upwelling zone, which is defined as 2.5°N-2.5°S. As a result, the equatorial upwelling supplies less Si(OH)₄ than NO₃ into the euphotic zone in the Wyrtki box, having a Si/N supply ratio of about 0.85 (2.5 vs. 2.96 mmol m^-2 day^-1). More Si(OH)⁴ than NO³ is taken up with a Si/N ratio of 1.17 (2.72 vs. 2.33 mmol m^-2 day^-1) within the euphotic zone. The difference between upwelling supply and biological uptake is balanced by nutrient regeneration and horizontal advection. Excluding regeneration, the net silicate and nitrate uptakes are nearly equal (1.76 vs. 1.84 mmol m^-2 day^-1). However, biogenic silica export production is slightly higher than organic nitrogen (1.74 vs. 1.59 mmol m^-2 day^-1) following a 1.1 Si/N ratio. In the central equatorial Pacific, low silicate concentrations limit diatom growth; therefore, non-diatom new production accounts for most of the new production. Higher silicate supply in the east maintains elevated diatom growth rates and new production associated with diatoms dominate upwelling zone. In contrast, the new production associated with small phytoplankton is nearly constant or decreases eastward along the equator. The total new production has a higher rate in the east than in the west, following the pattern of surface silicate. This suggests that silicate regulates the diatom production, total new production, and thereby carbon cycle in this area. The modeled mean primary production is 48.4 mmol Cm^-2 day^-1, representing the lower end of direct field measurements, while new production is 15.0 mmol Cm^-2 day^-1, which compares well with previous estimates.

Johns, E., P.B. Ortner, R.H. Smith, C.R. Kelble, S.R. Cummings, J.C. Hendee, N. Melo, T.N. Lee, and E.J. Williams. New interdisciplinary oceanographic observations in the coastal waters adjacent to Florida Bay. Joint Conference on the Science and Restoration of the Greater Everglades and Florida Bay Ecosystem from Kissimmee to the Keys, Palm Harbor, FL, April 13-18, 2003. University of Florida Office of Conferences and Institutes, 45-47 (CD-ROM) (2003).

No abstract.

Johns, W.E., R.J. Zantopp, and G.J. Goni. Cross-gyre transport by North Brazil Current rings. In Interhemispheric Water Exchange in the Atlantic Ocean, G.J. Goni and P. Malanotte-Rizzoli (eds.). Elsevier Oceanography Series, 68 (ISBN 0444512675), 411-441 (2003).

Recent observations collected as part of the North Brazil Current Rings Experiment are used to assess the role played by NBC rings in tropical to subtropical cross-gyre transport in the Atlantic Ocean. During the course of the 20 month experiment, four different NBC Rings were surveyed by ships and 12 additional rings were identified by moored current meters and temperature/salinity recorders. Of the total of 16 rings observed, four were subsurface-intensified rings with little or no surface signal. Except for these subsurface rings, generally good agreement was found in the identification of NBC rings during the experiment by various techniques including satellite altimetry, ocean color, and inverted echo sounders. The observations of water properties in the ring cores provided by the in-situ temperature and salinity measurements are used to estimate the trapped core volumes of South Atlantic water in the rings. Based on these new measurements we estimate a ring formation rate of 8-9 rings per year, with no apparent seasonal variation in the formation rate. However, the surface rings show a seasonal cycle in their vertical penetration and associated trapped core volumes. Deeper rings tend to occur in fall and early winter, while shallower rings occur in spring and summer. The subsurface rings are usually smaller in diameter than the surface rings (average radius of maximum velocity 100 km versus 130 km), but have a thicker layer of trapped South Atlantic water and consequently a larger transport per ring. The average ring-induced transport including all ring types is about 1.1 Sv per ring, leading to an estimate of 9.3 Sv for the total annualized ring transport. This value is nearly twice that of most previous estimates, and suggests that NBC rings could account for more than half of the northward transport in the warm limb of the Atlantic meridional overturning cell.

Jurado, J.L., G.L. Hitchcock, and P.B. Ortner. The roles of freshwater discharge, advective processes, and silicon cycling in the development of diatom blooms in coastal waters of the southwestern Florida Shelf and northwestern Florida Bay (1999-2001). Joint Conference on the Science and Restoration of the Greater Everglades and Florida Bay Ecosystem from Kissimmee to the Keys, Palm Harbor, FL, April 13-18, 2003. University of Florida Office of Conferences and Institutes, 119-121 (CD-ROM) (2003).

No abstract.

Kaplan, J., and M. DeMaria. Large-scale characteristics of rapidly intensifying tropical cyclones in the North Atlantic basin. Weather and Forecasting, 18(6):1093-1108 (2003).

The National Hurricane Center (NHC) and Statistical Hurricane Intensity Prediction Scheme (SHIPS) databases are employed to examine the large-scale characteristics of rapidly intensifying Atlantic basin tropical cyclones. In this study, rapid intensification (RI) is defined as approximately the 95th percentile of over-water 24-h intensity changes of Atlantic basin tropical cyclones that developed from 1989 to 2000. This equates to a maximum sustained surface wind speed increase of 15.4 m s^-1 (30 kt) over a 24-h period. It is shown that 31% of all tropical cyclones, 60% of all hurricanes, 83% of all major hurricanes, and all category 4 and 5 hurricanes underwent RI at least once during their lifetimes. The mean initial (t = 0 h) conditions of cases that undergo RI are compared to those of the non-RI cases. These comparisons show that the RI cases form farther south and west and have a more westward component of motion than the non-RI cases. In addition, the RI cases are typically intensifying at a faster rate during the previous 12 h than the non-RI cases. The statistical analysis also shows that the RI cases are further from their maximum potential intensity and form in regions with warmer SSTs and higher lower-tropospheric relative humidity than the non-RI cases. The RI cases are also embedded in regions where the upper-level flow is more easterly and the vertical shear and upper-level forcing from troughs or cold lows is weaker than is observed for the non-RI cases. Finally, the RI cases tend to move with the flow within a higher layer of the atmosphere than the non-RI cases. A simple technique for estimating the probability of RI is described. Estimates of the probability of RI are determined using the predictors for which statistically significant differences are found between the RI and non-RI cases. Estimates of the probability of RI are also determined by combining the five predictors that had the highest individual probabilities of RI. The probability of RI increases from 1% to 41% when the total number of thresholds satisfied increases from zero to five. This simple technique was used in real time for the first time during the 2001 Atlantic hurricane season as part of the Joint Hurricane Testbed (JHT).

Katsaros, K.B. Book review, Atmosphere-Ocean Interactions, Volume 1, W. Perrie (ed.). Oceanography, 16(4):106-108 (2003).

No abstract.

Katsaros, K.B. Satellite versus in-situ measurements at the air-sea interface. In Handbook of Weather, Climate and Water: Dynamics, Climate, Physical Meteorology, Weather Systems, and Measurements, T.D. Potter and B.R. Colman (eds.). John Wiley and Sons, 885-893 (2003).

In this chapter we explore the trade-offs in selecting surface in-situ versus satellite platforms to measure properties near or at the air-sea interface. The most obvious difference between the two observing platforms is sampling coverage in time and space. A surface platform can obtain continuous measurements at a point, while a polar-orbiting satellite instrument samples, at most, twice per day depending on the swath width of the sensor. A geostationary satellite can sample the surface as frequently as every 15 minutes (once per hour is typical), but the high altitude (38,000 km) limits the resolution that is achievable for some sensors. To focus the discussion, we compare the following two variables commonly measured by both in-situ and satellite systems: the sea surface temperature (SST) and surface wind speed, U, or wind vector, [overline] U.

Katsaros, K.B., A.M. Mestas-Nunez, A. Bentamy, and E.B. Forde. Wind bursts and enhanced evaporation in the tropical and subtropical Atlantic Ocean. In Interhemispheric Water Exchange in the Atlantic Ocean, G.J. Goni and P. Malanotte-Rizzoli (eds.). Elsevier Oceanography Series, 68 (ISBN 0444512675), 463-474 (2003).

Satellite-derived estimates of weekly latent heat flux for the tropical and subtropical Atlantic Ocean (40°S to 40°N) were calculated for a one-year period from September 30, 1996 to September 28, 1997 (52 weeks). The oceanic variables required to estimate evaporation (sea surface temperature, surface wind speed, and surface air humidity) were obtained from sensors on several polar-orbiting satellites including the European Remote Sensing satellite 2 (ERS-2), the NASA scatterometer (NSCAT), and the Special Sensor Microwave/Imager (SSM/I). During this period, high values of the weekly satellite estimates of wind speed and latent heat flux were found over the northeast and southeast trade wind regions. In these regions, the 52-week average fields showed wind speeds greater than about 7 m s^-1 and associated evaporation rates greater than 120 W m^-2. The annual cycle dominates the temporal evolution of sea surface temperature but is hardly noticeable in wind speed and latent heat flux, which are dominated by large 3-4 week fluctuations. The most significant event during our period of study was a strong northeast trade wind burst that originated near the northwest African coast in early February 1997. It persisted for five weeks as it crossed the North Atlantic Ocean and finally dissipated in the Caribbean Sea in early March 1997. In the southeast trade region, a similar but less intense period of higher flux was observed during July 1997. These large-scale wind bursts illustrate the strong role that the Atlantic trade winds play in enhancing evaporation.

Kelble, C.R., G.L. Hitchcock, P.B. Ortner, and J.N. Boyer. A recent study of the light environment in Florida Bay. Joint Conference on the Science and Restoration of the Greater Everglades and Florida Bay Ecosystem from Kissimmee to the Keys, Palm Harbor, FL, April 13-18, 2003. University of Florida Office of Conferences and Institutes, 48-50 (CD-ROM) (2003).

No abstract.

Knaff, J.A., N. Wang, M. DeMaria, M. Zehr, J.S. Griffin, and F.D. Marks. A demonstration of real-time transmission and display of GOES imagery aboard the NOAA P-3 aircraft during the 2002 hurricane season. Preprints, 12th Conference on Satellite Meteorology and Oceanography and 3rd Conference on Artificial Intelligence Applications to Environmental Science, Long Beach, CA, February 8-13, 2003. American Meteorological Society, Boston, 5 pp. (CD-ROM) (2003).

No abstract.

Kollias, P., B.A. Albrecht, and F.D. Marks. Cloud radar observations of vertical drafts and microphysics in convective rain. Journal of Geophysical Research, 108(D2):4053, doi:10.1029/2001JD002033 (2003).

Observations of convective precipitation using a 94-GHz cloud radar are presented. Due to Mie scattering, the Doppler power spectra collected at vertical incidence contains characteristics of the scatterers (hydrometeors). These characteristics are used for the retrieval of the vertical air motion and the associated raindrop size distribution in an attempt to accurately map the time-height structure of the vertical air motion and raindrop fields within intense convective precipitation. The data provide strong evidence of the interaction between draft intensity and raindrop size distribution and highlight the variability of convective precipitation at small scales. Horizontal sorting of the raindrops caused by the air motion is documented. Signal attenuation measured at 94 GHz is shown to be well correlated to rainfall rates. The observations demonstrate the capability of 94-GHz cloud radars for studies of precipitation processes at low altitudes even under intense convective conditions.

Landsea, C.W., C. Anderson, N. Charles, G. Clark, J.P. Dunion, J. Fernandez-Partagas, P. Hungerford, C. Neumann, and M. Zimmer. The Atlantic hurricane database re-analysis project: Results for the first 60 years, 1851-1910. Preprints, 14th Symposium on Global Change and Climate Variations, Long Beach, CA, February 9-13, 2003. American Meteorological Society, Boston, 36 pp. (CD reprint) (2003).

No abstract.

Langdon, C., W.S. Broecker, D.E. Hammond, E. Glenn, K. Fitzsimmons, S.G. Nelson, T.-H. Peng, I. Hajdas, and G. Bonani. Effect of elevated CO₂ on the community metabolism of an experimental coral reef. Global Biogeochemical Cycles, 17(1):1011, doi:10.1029/2002GB001941 (2003).

The effect of elevated pCO₂ on the metabolism of a coral reef community dominated by macroalgae has been investigated utilizing the large 2650 m³ coral reef mesocosm at the Biosphere-2 facility near Tucson, Arizona. The carbonate chemistry of the water was manipulated to simulate present-day and a doubled CO₂ future condition. Each experiment consisted of a one-two month preconditioning period followed by a seven-nine day observational period. The pCO₂ was 404 � 63 µatm during the present-day pCO₂ experiment and 658 � 59 µatm during the elevated pCO₂ experiment. Nutrient levels were low and typical of natural reefs waters (NO₃^- 0.5-0.9 µM, NH₄⁺ 0.4 µM, PO₄^3- 0.07-0.09 µM). The temperature and salinity of the water were held constant at 26.5 � 0.2°C and 34.4 � 0.2 ppt. Photosynthetically available irradiance was 10 � 2 during the present-day experiment and 7.4 � 0.5 mol photons m^-2 d^-1 during the elevated pCO₂ experiment. The primary producer biomass in the mesocosm was dominated by four species of macroalgae: Haptilon cubense, Amphiroa fragillisima, Gelidiopsis intricata, and Chondria dasyphylla. Algal biomass was 10.4 mol C m^-2 during the present-day and 8.7 mol C m^-2 and during the elevated pCO₂ experiments. As previously observed, the increase in pCO₂ resulted in a decrease in calcification from 0.041 � 0.007 to 0.006 � 0.003 mol CaCO₃ m^-2 d^-1. Net community production (NCP) and dark respiration did not change in response to elevated pCO₂. Light respiration measured by a new radiocarbon isotope dilution method exceeded dark respiration by a factor of 1.2 � 0.3 to 2.1 � 0.4 on a daily basis and by 2.2 � 0.6 to 3.9 � 0.8 on an hourly basis. The 1.8-fold increase with increasing pCO₂ indicates that the enhanced respiration in the light was not due to photorespiration. Gross production (GPP) computed as the sum of NCP plus daily respiration (light + dark) increased significantly (0.24 � 0.03 vs. 0.32 � 0.04 mol C m^-2 d^-1). However, the conventional calculation of GPP based on the assumption that respiration in the light proceeds at the same rate as the dark underestimated the true rate of GPP by 41-100% and completely missed the increased rate of carbon cycling due to elevated pCO₂. We conclude that under natural, undisturbed, nutrient-limited conditions elevated CO₂ depresses calcification, stimulates the rate of turnover of organic carbon, particularly in the light, but has no effect on net organic production. The hypothesis that an increase pCO₂ would produce an increase in net production that would counterbalance the effect of decreasing saturation state on calcification is not supported by these data.

Lee, K., S.-D. Choi, G.-H. Park, R.H. Wanninkhof, T.-H. Peng, R.M. Key, C.L. Sabine, R.A. Feely, J.L. Bullister, F.J. Millero, and A. Kozyr. An updated anthropogenic CO₂ inventory in the Atlantic Ocean. Global Biogeochemical Cycles, 17(4):1116, doi:10.1029/2003GB002067 (2003).

This paper presents a comprehensive analysis of the basin-wide inventory of anthropogenic CO₂ in the Atlantic Ocean based on high-quality inorganic carbon, alkalinity, chlorofluorocarbon, and nutrient data collected during the World Ocean Circulation Experiment (WOCE) Hydrographic Program, the Joint Global Ocean Flux Study (JGOFS), and the Ocean-Atmosphere Carbon Exchange Study (OACES) surveys of the Atlantic Ocean between 1990 and 1998. Anthropogenic CO₂ was separated from the large pool of dissolved inorganic carbon using an extended version of the DELTA-C* method originally developed by Gruber et al. (1996). The extension of the method includes the use of an optimum multiparameter analysis to determine the relative contributions from various source water types to the sample on an isopycnal surface. Total inventories of anthropogenic CO₂ in the Atlantic Ocean are highest in the subtropical regions at 20°-40°, whereas anthropogenic CO₂ penetrates the deepest in high-latitude regions (>40°N). The deeper penetration at high northern latitudes is largely due to the formation of deep water that feeds the Deep Western Boundary Current, which transports anthropogenic CO₂ into the interior. In contrast, waters south of 50°S in the Southern Ocean contain little anthropogenic CO₂. Analysis of the data collected during the 1990-1998 period yielded a total anthropogenic CO₂ inventory of 28.4 � 4.7 Pg C in the North Atlantic (equator-70°N) and of 18.5 � 3.9 Pg C in the South Atlantic (equator-70°S). These estimated basin-wide inventories of anthropogenic CO₂ are in good agreement with previous estimates obtained by Gruber (1998), after accounting for the difference in observational periods. Our calculation of the anthropogenic CO₂ inventory in the Atlantic Ocean, in conjunction with the inventories calculated previously for the Indian Ocean (Sabine et al., 1999) and for the Pacific Ocean (Sabine et al., 2002), yields a global anthropogenic CO₂ inventory of 112 � 17 Pg C that has accumulated in the world oceans during the industrial era. This global oceanic uptake accounts for approximately 29% of the total CO₂ emissions from the burning of fossil fuels, land-use changes, and cement production during the past 250 years.

Lee, T.N., E. Williams, E. Johns, R.H. Smith, and N. Melo. Circulation and exchange processes within Florida Bay interior basins. Joint Conference on the Science and Restoration of the Greater Everglades and Florida Bay Ecosystem from Kissimmee to the Keys, Palm Harbor, FL, April 13-18, 2003. University of Florida Office of Conferences and Institutes, 26-28 (CD-ROM) (2003).

No abstract.

Lee, W.-C., F.D. Marks, and C. Walther. Airborne Doppler radar data analysis workshop. Bulletin of the American Meteorological Society, 84(8):1063-1075 (2003).

The Airborne Doppler Radar Data Analysis Workshop, sponsored by the Atmospheric Technology Division (ATD) of the National Center for Atmospheric Research (NCAR), was the first to focus on analyzing airborne Doppler radar data. The workshop (held 13-16 March 2000 at NCAR) aimed to (1) summarize the current airborne Doppler radar data analysis techniques, and (2) promote the use of airborne Doppler radar data in the atmospheric sciences community. The workshop also intended to encourage new users to analyze this Doppler data and to provide a forum for experienced users to exchange ideas and discuss problems related to analyzing the data. It also provided a forum to train the users in planning future airborne Doppler radar programs. Graduate students, recent PhDs, faculty and researchers participantsthe leading experts in the fieldcovered the theory of airborne Doppler radar, experiment design, standard data analysis procedures and software, and recently developed analysis techniques. Eight working groups were organized among the participants to analyze preselected airborne Doppler radar datasets collected in past experiments using the standard software available from NCAR. Each working group used standard data analysis procedures to obtain dual-Doppler radar winds from raw airborne Doppler radar data.

Lirman, D., B. Orlando, S. Macia, D. Manzello, L. Kaufman, P. Biber, and T. Jones. Coral communities of Biscayne Bay, Florida and adjacent offshore areas: Diversity, abundance, distribution, and environmental correlates. Aquatic Conservation: Marine and Freshwater Ecosystems, 13(2):121-135 (2003).

Hardbottom habitats of Biscayne Bay, a shallow lagoon adjacent to the city of Miami, Florida, contain a limited number of coral species that represent a small subset of the species found at nearby offshore hardbottom and reef habitats of the Florida Reef Tract. Although the physical characteristics of this basin make it a marginal environment for coral growth, the presence of dense populations of Siderastrea radians and Porites furcata indicate that these, as well as other corals that are found at lower densities, are able to tolerate extreme and fluctuating conditions. Three factors, temperature, sedimentation, and salinity, appear to limit coral abundance, diversity, and distribution within Biscayne Bay. Temperatures exhibit high frequencies of extreme high and low values known to cause coral stress and mortality elsewhere. Similarly, sedimentation rates are very high and sediment resuspension caused by currents, storms, and boating activities commonly bury corals under sediment layers. Sediment burial was shown experimentally to influence growth and mortality of S. radians. The salinity of Biscayne Bay is influenced by freshwater inputs from canal, sheetflow, and groundwater sources that create a near-shore environment with low mean salinity and high salinity fluctuation. Coral communities along this western margin have the lowest coral density and species richness. Chronic exposure to low salinity was shown experimentally to cause a decrease in the growth of S. radians. The location of Biscayne Bay, downstream of a large restoration effort planned for the Everglades watershed, highlights the need to understand the relationship between the physical environment and the health of benthic communities. The data presented here provide the type of scientific information needed so that management decisions can take into account the potential impacts of human activities on the health of coral populations that are already near their tolerance limits for temperature, salinity, and sedimentation.

Liu, K.-K., T.-H. Peng, P.-T. Shaw, and F.-K. Shiah. Circulation and biogeochemical processes in the East China Sea and the vicinity of Taiwan: An overview and a brief synthesis. Deep-Sea Research, Part II, 50(6-7):1055-1064 (2003).

The East China Sea shelf (including the Yellow Sea and the Bohai Sea) is a very challenging system for hydrodynamic and biogeochemical studies due to its complicated physical and chemical forcing. It receives much attention because of its capacity for absorbing atmospheric CO₂ in spite of large riverine fluxes of terrigenous carbon. This volume reports field observations and modeling studies during the Kuroshio Edge Exchange Processes and ensuing projects, which are a part of the continental margins study in the Joint Global Ocean Flux Study. A three-dimensional numerical model has been developed to simulate the climatological circulation in the East China Sea. The model result is supported by observations in the seas around Taiwan. The significance of inflow from the Taiwan Strait is emphasized. Geochemical tracers prove useful in understanding the water and material transport. Biogeochemical studies suggest very efficient recycling of organic carbon by bacterial and protozoan consumption in the shelf water, but a finite amount of particulate organic carbon with a significant terrigenous fraction is exported from the shelf. The fine-grained sediments in the inner shelf appear to be an important source of organic carbon for export. Future studies are needed to improve our understanding of key physical and biogeochemcial processes, to develop coupled physical-biogeochemical models, and to catch and survey the elusive spring algal bloom. A tantalizing goal of our ongoing effort is to document or even to predict future changes in the East China Sea shelf caused by the operation of the Three-Gorge Dam, which is under construction in the middle reach of the Yangtze River.

Lumpkin, R. Decomposition of surface drifter observations in the Atlantic Ocean. Geophysical Research Letters, 30(14):1753, doi:10.1029/2003GL017519 (2003).

Surface drifter observations are decomposed into mean, seasonal (annual and semiannual), and eddy components via Gauss-Markov estimation. This approach helps separate seasonal fluctuations and mean values in the observationally-sparse tropical and South Atlantic, where monthly mean values cannot be calculated at the spatial scale of the major currents. In some regions, large differences are found between these means and those obtained by simple binned averaging. The differences are attributed to inhomogeneous sampling of seasonal variability, and to the inherent bias of Lagrangian observations towards periods of low velocity. The analysis reveals strong seasonal variations of some surface currents, including a significant late spring reversal of the western North Equatorial Counter-Current.

Lumpkin, R., and K. Speer. Large-scale vertical and horizontal circulation in the North Atlantic Ocean. Journal of Physical Oceanography, 33(9):1902-1920 (2003).

Observations of large-scale hydrography, air-sea forcing, and regional circulation from numerous studies are combined by inverse methods to determine the basin-scale circulation, average diapycnal mixing, and adjustments to air-sea forcing of the North Atlantic Ocean. Dense overflows through the Denmark Strait and Faroe Bank channels are explicitly included and are associated with strong vertical and lateral circulation and mixing. These processes in the far northern Atlantic play a fundamental role in the meridional overturning circulation for the entire ocean, accompanied by an upper cell of mode-water and intermediate-water circulation. The two cells converge roughly at the mean depth of the midocean ridge crest. The Labrador Sea Water layer lies within this convergence. South of the overflow region, model-derived mean diapycnal diffusivities are O(10^-5 m² s^-1) or smaller at the base of the thermocline, and diapycnal advection is driven primarily by air-sea transformation on outcropping layers.

Macdonald, A.M., M.O. Baringer, R. Wanninkhof, K. Lee, and D.W.R. Wallace. A 1998-1992 comparison of inorganic carbon and its transport across 24.5°N in the Atlantic. Deep-Sea Research, Part II, 50(22-26):3041-3064 (2003).

In January and February 1998, when an unprecedented fourth repetition of the zonal hydrographic transect at 24.5°N in the Atlantic was undertaken, carbon measurements were obtained for the second time in less than a decade. The field of total carbon along this section is compared to that provided by a 1992 cruise which followed a similar path (albeit in a different season). Consistent with the increase in atmospheric carbon levels, an increase in anthropogenic carbon concentrations of 8 ± 3 mol kg^-1 was found in the surface layers. Using an inverse analysis to determine estimates of absolute velocity, the flux of inorganic carbon across 24.5° is estimated to be -0.74 ± 0.91 and -1.31 ± 0.99 Pg Cyr^-1 southward in 1998 and 1992, respectively. Estimates of total inorganic carbon flux depend strongly upon the estimated mass transport, particularly of the Deep Western Boundary Current. The 1998 estimate reduces the large regional divergence in the meridional carbon transport suggested by previous studies and brings into question the idea that the tropical Atlantic constantly outgasses carbon, while the subpolar Atlantic sequesters it. Uncertainty in the carbon transports themselves, dominated by the uncertainty in the total mass transport estimates, are a hindrance to determining the "true" picture. The flux of anthropogenic carbon (C*_ANTH) across the two transects is estimated as northward at 0.20 ± 0.08 and 0.17 ± 0.06 Pg Cyr^-1 for the 1998 and 1992 sections, respectively. The net transport of C*_ANTH across 24.5°N is strongly affected by the difference in concentrations between the northward flowing shallow Florida Current and the mass balancing, interior return flow. The net northward transport of C*_ANTH is opposite the net flow of total carbon and suggests, as has been found by others, that the pre-industrial southward transport of carbon within the Atlantic was stronger than it is today. Combining these flux results with estimates of atmospheric and riverine inorganic carbon input, it is determined that today's oceanic carbon system differs from the pre-industrial system in that today there is an uptake of anthropogenic carbon to the south that is advected northward and stored within the North Atlantic basin.

Manzello, D., and D. Lirman. The photosynthetic resilience of Porites furcata to salinity disturbance. Coral Reefs, 22(4):537-540 (2003).

No abstract.

Marks, F.D. Hurricanes. In Encyclopedia of Atmospheric Sciences, Elsevier Science Ltd., London, UK, 942-966 (2003).

No abstract.

Marks, F.D. Hurricanes. In Handbook of Weather, Climate and Water: Dynamics, Climate, Physical Meteorology, Weather Systems, and Measurements, T.D. Potter and B.R. Colman (eds.). John Wiley and Sons, 641-676 (2003).

No abstract.

Marks, F.D. State of the science: Radar view of tropical cyclones. In Radar and Atmospheric Science: A Collection of Essays in Honor of David Atlas, R.M. Wakimoto and R.C. Srivastava (eds.). Meteorological Monograph, Volume 30, No. 52, American Meteorological Society, Boston, 33-74 (2003).

No abstract.

Mayer, D.A., M.O. Baringer, and G.J. Goni. Comparison of hydrographic and altimeter based estimates of sea level height variability in the Atlantic Ocean. In Interhemispheric Water Exchange in the Atlantic Ocean, G.J. Goni and P. Malanotte-Rizzoli (eds.). Elsevier Oceanography Series, 68 (ISBN 0444512675), 23-48 (2003).

Our ability to understand the means by which mass and heat are exchanged between the tropics and subtropics is seriously compromised when using only sea level data because the exchange processes span a wide range of variability across the different dynamical regimes in our domain. Expendable bathythermograph (XBT) profiles and TOPEX/Poseidon (T/P) altimeter data are compared to temperature anomalies (TA) and to dynamic height anomalies (DHA) for the period 1993 through 1997 to determine how much can be inferred about the internal field of mass from sea level changes. Our focus is on the annual cycle along two well-sampled XBT sections on the western and eastern sides of the Atlantic Ocean from 10°S to 40°N. XBT profiles were matched (time/location) to Sea height anomalies (SHA) derived from T/P data, converted into DHA using TS relationships and then binned monthly into 2° of latitude by 4° of longitude boxes. The vertical mass distribution cannot always be inferred from SHA alone, unless there is a strong relationship between SHA and DHA and an understanding of the details of how temperature variability affects DHA. These relationships can be problematic if SHA are small. This occurs in zones of transition in the vicinity of troughs where small fluctuations in SHA belie the true nature of water column variability. These areas separate the mid-latitudes where surface buoyancy fluxes dominate from those in the equatorial region where ocean dynamics cause thermocline effects that dominate the forcing of sea level. Thus, the variability of SHA in transition regions tends to be small because both surface and thermocline variability may be significant but compensating in nature. This emphasizes how important direct observations (in-situ data) can be in interpreting SHA correctly. Strong relationships between SHA and DHA are suggested where more than half of the SHA variance in the annual cycle can be accounted for by DHA (approximately 30% of the positions along the two XBT sections). These relationships between SHA and DHA for residual variability (obtained by removing the annual cycle) are weak. The exceptions are in two areas of large sea height variability in the western basin where there is significant interannual variability. The first is in the tropics in the vicinity of the tropical gyre trough near 50°W, 8°N. The second is in the Gulf Stream near 70°W, 38°N. An analysis of Panulirus data at (32.2°N, 64.5°W) suggests that in-situ data may be needed down to at least 1000 m where interannual variability accounts for about 40% of the SHA variance.

McGillis, W.R., and R.H. Wanninkhof. SOLAS (Surface Ocean Lower Atmosphere Study) holds first international summer school. U.S. JGOFS Newsletter, 12(3):14-15(2003).

No abstract.

Meinen, C.S., and D.S. Luther. Comparison of methods of estimating mean synoptic current structure in "stream coordinates" reference frames with an example from the Antarctic Circumpolar Current. Deep-Sea Research, Part I, 50(2):201-220 (2003).

Stream coordinates techniques, that is, methods of deriving the mean "synoptic" structures of narrow meandering ocean currents from Eulerian measurements, have been in use for nearly two decades and have resulted in improvements in our understanding of the dynamics and transports of such currents. A two-year experiment in the Sub-Antarctic Front (SAF) southwest of Tasmania, involving overlapping arrays of inverted echo sounders and horizontal electric field recorders, has provided an opportunity to test various stream coordinates methods. The methods differ significantly in how well, or even if, they can reveal divergence or convergence of the meandering current, and whether they accurately reproduce the current's horizontal structure and transport. Cross-stream distance was determined either via a frozen-field assumption or as the distance to an optimally interpolated (OI) origin contour; downstream direction was determined either as the local direction which maximized the vertical shear of horizontal velocity or as the tangent line to the OI mapped core contour. All combinations of these distance and direction definitions were tested. The use of a frozen field assumption in determining cross-stream distance yields overly smooth along-stream velocity cross-sections and overestimated transports. The vertical shear definition of downstream direction results in a false rotation of cross-stream flows into along-stream flows near the flanks of the current. The preferred methods define the horizontal location of the front with two-dimensional arrays of instruments (e.g., inverted echo sounders or moored current meters). Methods employing the assumptions of a meandering "frozen-field" baroclinic structure or the use of the local vertical shear of the horizontal velocity to determine the downstream direction should be avoided, if possible, particularly in the SAF.

Meinen, C.S., D.S. Luther, D.R. Watts, A.D. Chave, and K.L. Tracey. Mean stream coordinates structure of the Subantarctic Front: Temperature, salinity, and absolute velocity. Journal of Geophysical Research, 108(C8):3263, doi:10.1029/2002JC001545 (2003).

The mean synoptic structure of the northern, strongest branch of the Antarctic Circumpolar Current southwest of Tasmania, at the Subantarctic Front (SAF), is estimated by a stream coordinates analysis of data from overlapping arrays of Inverted Echo Sounders (IESs) and Horizontal Electric Field Recorders deployed during the 1995-1997 Sub-Antarctic Flux and Dynamics Experiment. The stream coordinates are derived from a daily objective mapping of the temperature field obtained from combining the IES travel time measurements with an empirical look-up table constructed from the extensive hydrography acquired during WOCE. Full-water-column stream-coordinates sections of temperature, salinity, and absolute velocity are presented and compared with prior observations. The along-stream current has a single peak with surface velocities reaching about 50 cm s^-1. The vertical structure of the along-stream velocity is roughly consistent with a combined external and first internal normal mode description that is adapted to the buoyancy frequency as it varies across the front, although there are some significant differences. The cross-stream structure of along-stream velocity is very nearly symmetric about the jet axis, but the lateral shear magnitude is slightly larger on the cold side of the SAF. Separating the baroclinic and barotropic currents reveals that the SAF currents are diffluent, primarily baroclinically, in the cross-stream direction. Baroclinic cross-stream diffluence of approximately 0.23 Sv per km (Sv = 10⁶ m³ s^-1), or about 16 Sv per degree of longitude at 51°S. The 2-year mean total SAF transport is 75 Sv (for a 220 km width); the barotropic contribution is small (8 Sv) but not negligible.

Melo, N., T.N. Lee, E.J. Williams, D. Smith, M. Framinan, R.H. Smith, and E. Johns. A movie of Florida Bay sea level response to local wind forcing. Joint Conference on the Science and Restoration of the Greater Everglades and Florida Bay Ecosystem from Kissimmee to the Keys, Palm Harbor, FL, April 13-18, 2003. University of Florida Office of Conferences and Institutes, 59-60 (CD-ROM) (2003).

No abstract.

Mo, Q., A.G. Detwiler, J. Hallett, and R.A. Black. Horizontal structure of the electric field in the stratiform region of an Oklahoma mesoscale convective system. Journal of Geophysical Research, 108(D7):4225, doi:10.1029/2001JD001140 (2003).

This analysis combines vertical electric field components E_z observed by two research aircraft flying horizontally at two levels, with vertical soundings of thermodynamic parameters and E_z made by five balloons, to produce a quasi-three-dimensional view of the space charge distribution in the trailing stratiform cloud region behind a mesoscale convective system (MCS) that developed in central Oklahoma late in the afternoon of 2 June 1991. The balloons were launched serially at one-hour intervals from two sites separated by 80 km along a north-south line as the MCS moved eastward, yielding two east-west time-height cross-sections of the E_z structure within the quasi-steady state trailing stratiform region behind the MCS. The balloon measurements are consistent with a vertical stack of five rearward- and downward-sloping horizontal sheets of charge of alternating polarity, beginning at the bottom with a negative charge layer below the 0°C level and a positive layer near the 0°C level. This structure persisted for more than 2 hours. The two aircraft flew back and forth along a north-south line through the balloon launch sites during the balloon launch period. Aircraft measurements demonstrated that the vertical electric field (E_z) at constant altitude varied in the north-south direction. The peak magnitudes of E_z deduced from the airborne instrument systems agreed with the magnitudes deduced from the balloon measurements at the aircraft altitudes of 4.5 km and 5.8 km AGL. Rapid reversals in polarity of E_z with peak magnitude >50 kV m^-1 observed by the aircraft at 4.5 km, just above the 0°C level, confirms the thin concentrated positive charge layer observed there by balloons and suggests that this charge layer is undulating above and below 4.5 km altitude, at least in the north-south direction. Microphysically, this layer contained large aggregates and pockets of low cloud liquid water concentration. At the 5.8 km level, the polarity of E_z was always positive but the magnitude varied from zero to 25 kV m^-1. Aircraft-observed E_z at both altitudes varied on horizontal scales of ~10 km or greater at both levels, suggesting that the charge density derived using the one-dimensional infinite-layer Gauss's law approximation applied to the balloon soundings of E_z is valid in this study. These observations show that layers of charge can persist for hours as they advect rearward in a storm-relative sense, possibly due to continuing in situ charge separation, and/or due to weak dispersion, slow recombination, and slow settling of charge attached to low mobility low terminal velocity ice hydrometeors.

Molinari, R.L., and A.M. Mestas-Nunez. North Atlantic decadal variability and the formation of tropical storms and hurricanes. Geophysical Research Letters, 30(10):1541, doi:10.1029/200GL016462 (2003).

Both the annual number of Atlantic tropical storms forming south of 23.5°N and of Atlantic major hurricanes increased between the 1970s-1980s and 1995-2000. These increases are coincident with a multi-decadal warming in North Atlantic SST, suggesting that the high activity of 1995-2000 may persist for the next ~10 to 40 years. However, during 1950-2000 strong decadal oscillations are superimposed on the multi-decadal changes in both SST and tropical storms (positive SST anomalies, increased storm activity). We appear to be entering a negative phase of the decadal SST signal implying that tropical storm and, most likely, major hurricane activity may be reduced in the next several years rather than remain at the very high 1995-2000 level when both signals were in their positive phase. Tropical storm activity during 2001 and 2002 is less than expected only from the multi-decadal signal but for 2002 the main cause may be El Ni�o.

Molinari, R.L., S. Bauer, D.P. Snowden, G.C. Johnson, B. Bourles, Y. Gouriou, and H. Mercier. A comparison of kinematic evidence for tropical cells in the Atlantic and Pacific Oceans. In Interhemispheric Water Exchange in the Atlantic Ocean, G.J. Goni and P. Malanotte-Rizzoli (eds.). Elsevier Oceanography Series, 68 (ISBN 0444512675), 269-286 (2003).

Kinematic evidence for the existence of Tropical Cells (TC) in the Atlantic Ocean is offered. Mean sections of meridional velocity, its horizontal divergence and vertical velocity are estimated from 12 available sections centered at about 35°W. Of the 12 sections, six were occupied in March and April, thus there is a boreal spring bias to the observations. Equatorial upwelling and off-equatorial downwelling, between 3°N and 6°N, represent the southern and northern boundaries of a northern hemisphere TC. Uncertainties for the estimates of average quantities are large. However, favorable comparisons with observational representations of Pacific TCs provide support for the existence of a northern hemisphere Atlantic TC.

Owens, B.F., and C.W. Landsea. Assessing the skill of operational Atlantic seasonal tropical cyclone forecasts. Weather and Forecasting, 18(1):45-54 (2003).

Since 1984, William Gray of Colorado State University and a team of researchers have been issuing seasonal tropical cyclone forecasts for the North Atlantic Ocean. Prior to this, little work had been done in the area of long-term tropical cyclone forecasting because researchers saw minimal potential skill in any prediction models and no obvious benefits to be gained. However, seasonal forecasts have been attracting more attention as economic and insured losses from hurricane-related catastrophes rose sharply during recent decades. Initially, the forecasts issued by Gray consisted of output from simple statistical prediction models. Over time, the models became increasingly more complex and sophisticated, with new versions being introduced in 1992, 1993, 1994, 1996, and 1997. In addition, based on a combination of experience with the statistical models and other qualitative considerations such as examinations of analog years, the statistical forecasts were modified to create adjusted seasonal forecasts. This analysis assessed the skill demonstrated, if any, of both the statistical and adjusted forecasts over the benchmarks of climatology and persistence and examined whether the adjusted forecasts were more accurate than the statistical forecasts. The analysis indicates that, over the past 18 years, both the statistical and adjusted forecasts demonstrated some skill over climatology and persistence. There is also evidence to suggest that the adjusted forecast was more skillful than the statistical model forecast.

Palmer, D.R. On the interpretation of measurements of acoustic backscatter from dredged-material plumes. Journal of Marine Environmental Engineering, 7(2):125-152 (2003).

During the Mobile, Alabama Field Data Collection Project (MFDCP), a barge repeatedly released dredging material at an ocean dumpsite near Mobile Bay while a research ship tracked the resulting underwater plumes. This ship was equipped with high-frequency sonar systems and equipment for measuring water properties and collecting sediment and water samples. Ogushwitz has presented an analysis of the relationship between particle concentration in the plumes, as measured from water sampling, and sonar echo strength. To explain the great variability in echo strength measurements, Ogushwitz listed a number of possible sources of variability which we group into four categories: experimental design, plume characteristics, ambient ocean conditions, and instrumentation effects. Ogushwitz argued that one of these sources of variability, the tumbling of the irregularly shaped particles that comprised the plumes, could result in up to 7 dB variability in echo strength. The argument is based on the short-wavelength or geometrical acoustics result that the backscattered intensity is proportional to the geometrical area of the target particle as seen by the incident sonar beam. This argument is somewhat inconsistent, however, since it is known that the scattering took place in the long-wavelength or Rayleigh region. New analytic techniques have been developed since the publication of Ogushwitz's results that allow us to obtain a more accurate determination of the maximum variability in echo strength that can be attributed to particle shape. In this paper, we develop a formalism for applying these techniques to MFDCP. We find tumbling of irregularly shaped particles in the plume can only lead to a variability in the backscattered intensity of from 0.9 dB below the intensity for scattering from spheres to 3.8 dB above the intensity for spheres. We also use this formalism to discuss several of the sources of variability in Ogushwitz's list and their significance for estimating particle concentration from backscattered intensity. The discussion is framed in terms of the insonified volume determined by the sonar characteristics and defined such that at any specific time the received pressure field is the sum of the fields scattered by particles in this volume. The random distribution of the particles in the insonified volume leads to a Rayleigh distribution for the backscattered intensity. Ping-to-ping variability of the mean concentration of particles in the insonified volume can be used to characterize plume type. For dredging material plumes, this variability makes it very difficult, if not impossible, to obtain quality estimates of particle concentration based on knowledge of the acoustic intensity. In addition to this inverse scattering problem, we discuss the value of the images of plumes obtained from single-ping data or data averaged over a few pings. Despite their qualitative nature, these images have several valuable uses. We point out that quantitative plume images would have additional uses and that there does not seem to be any obstacle in developing, for a given experimental situation, a formalism for creating them.

Peng, T.-H., R. Wanninkhof, and R.A. Feely. Increase of anthropogenic CO₂ in the Pacific Ocean over the last two decades. Deep-Sea Research, Part II, 50(22-26):3065-3082 (2003).

The multiple-parameter linear regression method (Monitoring global ocean carbon inventories, Ocean Observing System Development Panel, Texas A&M University, College Station, TX, 1995, 54 pp; Global Biogeochem. Cycles, 13 (1999) 179) is used to compare inorganic carbon data from the GEOSECS CO₂ survey in the Pacific Ocean in 1973 to the WOCE/JGOFS global CO₂ survey in the 1990s. A model of total dissolved inorganic carbon (DIC) as a function of five variables (AOU, theta, S, Si, and PO₄) has been developed from the recent CO₂ survey data (namely CGC91 and CGC96) in the Pacific Ocean. After correcting for a systematic DIC offset of -30.3 ± 7 mol kg^-1 from the GEOSECS data, the residual DIC based on this model as computed from GEOSECS data has been used to estimate the anthropogenic CO₂ penetration in the Pacific Ocean. In the Northeast Pacific, we obtained an increase of CO₂ of 21.3 ± 7.9 mol m^-2 over the period from GEOSECS in 1973 to CGC91 in 1991. This gives a mean anthropogenic CO₂ uptake rate of 1.3 ± 0.5 mol m^-2 yr^-1 over this 17 year time period. In the South Pacific, north of 50°S between 180° and 120°W region, the integrated anthropogenic CO₂ inventory is estimated to be 19.7 ± 5.7 mol m^-2 over the period from GEOSECS in 1974 to CGC96 in 1996. The equivalent mean CO₂ uptake rate is estimated to be 0.9 ± 0.3 mol m^-2 yr^-1 over the 22 years. These results are compared with the isopycnal method (Nature, 396 (1998) 560) to estimate the anthropogenic CO₂ signal in the Northeast Pacific (30°N, 152°W) at the crossover region between CGC91 and GEOSECS. The results of the isopycnal method are consistent with those derived from the MLR method. Both methods show an increase in anthropogenic CO₂ inventory in the ocean over two decades that is consistent with the increase expected if the ocean uptake has kept pace with the atmospheric CO₂ increase.

Pielke, R.A., J. Rubiera, C. Landsea, M.L. Fernandez, and R. Klein. Hurricane vulnerability in Latin America and the Caribbean: Normalized damage and loss potentials. Natural Hazards Review, 4(3):101-114 (2003).

In late October 1998, the remnants of Hurricane Mitch stalled over Honduras and Nicaragua, killing more than 10,000 people and causing as much as $8.5 billion in damage. While Central America and the Caribbean have a history of natural disasters, the fatalities and destruction caused by Mitch were the greatest in at least several decades, prompting many questions including: What accounts for the extent of these losses? Is Mitch a harbinger of future disasters in the region? and What might be done in response? This paper seeks to shed light on these questions by examining the historical and geographic context of hurricane vulnerability in Latin America and the Caribbean. The paper examines trends in economic and other societal factors that increase vulnerability to hurricanes in Central America and the Caribbean and includes a case study of normalized hurricane losses in Cuba made possible by newly collected damage data published herein. The paper places its findings into the context of policies related to climate change and natural hazards.

Powell, M.D., P.J. Vickery, and T.A. Reinhold. Reduced drag coefficient for high wind speeds in tropical cyclones. Nature, 422:279-283 (2003).

The transfer of momentum between the atmosphere and the ocean is described in terms of the variation of wind speed with height and a drag coefficient that increases with sea surface roughness and wind speed. But direct measurements have only been available for weak winds; momentum transfer under extreme wind conditions has therefore been extrapolated from these field measurements. Global Positioning System sondes have been used since 1997 to measure the profiles of the strong winds in the marine boundary layer associated with tropical cyclones. Here we present an analysis of these data, which show a logarithmic increase in mean wind speed with height in the lowest 200 m, maximum wind speed at 500 and a gradual weakening up to a height of 3 km. By determining surface stress, roughness length, and neutral stability drag coefficient, we find that surface momentum flux levels off as the wind speeds increase above hurricane force. This behavior is contrary to surface flux parameterizations that are currently used in a variety of modeling applications, including hurricane risk assessment and prediction of storm motion, intensity, waves, and storm surges.

Proni, J.R., and R.I. McMillen. Distinguishing ambient sediments at sensitive coastal oceans. In Coastal Engineering VI: Computer Modelling and Experimental Measurements of Seas and Coastal Regions, C.A. Brebbia, D. Almorza, and F. Lopez-Aguayo (eds.). WIT Press, Southampton, 377-386 (2003).

Often during dredging, beach renourishment, or other coastal engineering activities, questions arise as to whether those activities are causing unintended, unexpected, deleterious environmental impacts. A typical question arising during dredged material disposal operations in a coastal zone is whether any of the discharged dredged material is being transported out of the designated disposal site to a sensitive coastal ocean site of concern. In Florida (USA), and in the Caribbean, a sensitive coastal ocean site of concern is typically a coral reef location. In dredging operations in Ft. Pierce, Florida, local citizens expressed concern about a "muck-like" substance, observed covering a coral site, and if it originated from the designated dredged-material disposal site. To address this concern, a long-term monitoring program has been undertaken to determine the following: (1) what other potential sources, besides the discharged dredged material, of the "muck-like" material may exist; (2) what are the biological, chemical, and sedimentary characteristics of the "muck-like" material; (3) do any of the other potential sources of material have similar characteristics; (4) do oceanographic and meteorological conditions favor the transport of dredged material from the disposal site to coastal site(s) of concern; and (5) what is the chronological history of the appearance of muck-like material at the site of concern? In this paper, a discussion of results obtained to date is presented. Potential other sources of the "muck-like" material are identified and discussed, which include upwelled Atlantic ocean water, flood control releases from canals and bays, and dredging site transport (in contrast to transport from the dredged-material disposal site). Oceanic current observations are presented together with a discussion of potential sediment transport pathways. Potential effects of meteorological phenomena on coastal sediments are also discussed. Statistical cluster analysis of biological parameters suggests an ability to distinguish dredging site-related organisms from coastal shelf organisms.

Richardson, P.L., and S.L. Garzoli. Characteristics of intermediate water flow in the Benguela Current as measured with RAFOS floats. Deep-Sea Research, Part II, 50(1):87-118 (2003).

Seven floats (not launched in rings) crossed over the mid-Atlantic Ridge in the Benguela extension with a mean westward velocity of around 2 cm/s between 22°S and 35°S. Two Agulhas rings crossed over the mid-Atlantic Ridge with a mean velocity of 5.7 cm/s toward 285°. This implies they translated at around 3.8 cm/s through the background velocity field near 750 m. The boundaries of the Benguela Current extension were clearly defined from the observations. At 750 m, the Benguela extension was bounded on the south by 35°S and the north by an eastward current located between 18°S and 21°S. Other recent float measurements suggest that this eastward current originates near the Trindade Ridge close to the western boundary and extends across most of the South Atlantic, limiting the Benguela extension from flowing north of around 20°S. The westward transport of the Benguela extension was estimated to be 15 Sv by integrating the mean westward velocities from 22°S to 35°S and multiplying by the 500 m estimated thickness of intermediate water. Roughly 1.5 Sv of this are transported by the ~3 Agulhas rings that cross the mid-Atlantic Ridge each year (as observed with altimetry). This value of the Benguela extension transport is the first one to have been obtained from long-term (two-year) observations and across the full width of the Benguela extension.

Rogers, R.F., S. Chen, J. Tenerelli, and H.E. Willoughby. A numerical study of the impact of vertical shear on the distribution of rainfall in Hurricane Bonnie (1998). Monthly Weather Review, 131(8):1577-1599 (2003).

Despite the significant impacts of torrential rainfall from tropical cyclones at landfall, quantitative precipitation forecasting (QPF) remains an unsolved problem. A key task in improving tropical cyclone QPF is understanding the factors that affect the intensity and distribution of rainfall around the storm. These include the storm motion, topography, and orientation of the coast, and interactions with the environmental flow. The combination of these effects can produce rainfall distributions that may be nearly axisymmetric or highly asymmetric and rainfall amounts that range from 1 or 2 cm to >30 cm. This study investigates the interactions between a storm and its environmental flow through a numerical simulation of Hurricane Bonnie (1998) that focuses on the role of vertical wind shear in governing azimuthal variations of rainfall. The simulation uses the high-resolution nonhydrostatic fifth-generation Pennsylvania State University-NCAR Mesoscale Model (MM5) to simulate the storm between 0000 UTC 22 August and 0000 UTC 27 August 1998. During this period significant changes in the vertical shear occurred in the simulation. It changed from strong west-southwesterly, and across track, to much weaker south-southwesterly, and along track. Nearly concurrently, the azimuthal distribution of convection changed from a distinct wavenumber-1 pattern to almost azimuthally symmetric by the end of the time period. The strongest convection in the core was generally located on the downshear left side of the shear vector when the shear was strong. The azimuthal distributions and magnitudes of low-level radial inflow, reflectivity, boundary layer divergence, and low-level vertical motion all varied consistently with the evolution of the vertical shear. Additionally, the vortex showed a generally downshear tilt from the vertical. The magnitude of the tilt correlated well with changes in magnitude of the environmental shear. The accumulated rainfall was distributed symmetrically across the track of the storm when the shear was strong and across track, and it was distributed asymmetrically across the track of the storm when the shear was weak and along track.

Sandrik, A., and C.W. Landsea. Chronological listing of tropical cyclones affecting north Florida and coastal Georgia, 1565-1899. NOAA Technical Memorandum, NWS SR-244 (PB2003-104513), 74 pp. (2003).

This chronology is a portion of an ongoing re-analysis project for tropical cyclone events along the Georgia and northeast Florida coasts, including inland north Florida and southeast Georgia. The domain for this study ranges from Savannah, Georgia in the north to Flagler Beach, Florida in the south, the adjacent coastal waters, the inland cities (and their surrounding areas) of Palatka, Gainesville, and Lake City in Florida and Waycross, Georgia. The number of hurricanes and principle areas affected after 1900 are considered to be fairly accurate, but are the subject of a reevaluation by the Hurricane Research Division (HRD) in Miami, Florida (Landsea et al., 1999, 2003). The intention of this study is to accurately extend the historical hurricane landfall data base for the study area back as far as possible, but at a minimum to 1800.

Schmid, C., Z.D. Garraffo, E. Johns, and S.L. Garzoli. Pathways and variability at intermediate depths in the tropical Atlantic. In Interhemispheric Water Exchange in the Atlantic Ocean, G.J. Goni and P. Malanotte-Rizzoli (eds.). Elsevier Oceanography Series, 68 (ISBN 0444512675), 233-268 (2003).

Oceanographic and meteorological data, as well as model results, are analyzed to study the pathways and the temporal variability of the intermediate depth (800-1100 m) flow in the tropical Atlantic (9°S to 7°N). The mean flow is dominated by zonal currents which interact with the western boundary current. These currents frequently experience reversals of the zonal and meridional flow. The primary focus in the analysis of the variability is on the region around 6°S. The observations reveal temporal variability on mesoscale, annual, and interannual time scales. Several westward propagating signals can be identified, with propagation velocities between 5 and 7 cm s^-1. Two zonal length scales (500-700 km and more than 2000 km) are observed. It is hypothesized that these are due to planetary waves. A comparative analysis of observations and model velocities reveals striking similarities in their time and length scales. Sample spectra of the model velocities show a dominant peak of the spectral energy density at a wave length between 500 km and 1100 km. Additionally, a longer wave with a zonal wave length of about 5000 km is present, which can not be resolved by the spectral analysis. In the time space the spectral analysis for the zonal and meridional velocity reveals coinciding peaks at periods of 45 days, 66 days, and one year. For the latter two periods, the energy for the two velocity components are quite similar. An analytical planetary wave solution shows that a superposition of a mesoscale and an annual planetary wave in sufficient to reproduce a large part of the variability found in the observations and the model. The wave with an annual period is most likely due to the annual cycle of the wind field.

Schmid, C., O. Boebel, W. Zenk, J.R.E. Lutjeharms, S.L. Garzoli, P.L. Richardson, and C. Barron. Early evolution of an Agulhas ring. Deep-Sea Research, Part II, 50(1):141-166 (2003).

Rings shed at the Agulhas retroflection are an integral part of interoceanic exchange south of Africa. There is clear evidence of westward ring translation from the northern Cape Basin across the South Atlantic Ocean. Early ring development and translation from the southern to the northern Cape Basin, however, are obscured by an intensely variable kinematic field close to the spawning site. In this study, unique in-situ observations, obtained in March to September 1997, are analyzed to improve the understanding of the early development of a juvenile Agulhas ring. In March, the ring was surveyed near 37°S, 16°E, approximately four months after its generation. Its strength and size were in the upper range typical for Agulhas rings, and its trapping depth extended down to at least 1600 dbar according to geostrophic velocities and RAFOS trajectories in the ring. Between March and September, the ring propagated in a general northwestward direction; however, RAFOS trajectories and MODAS sea-surface steric height fields revealed a large variability of the translation speed (3 cm s^-1 to more than 20 cm s^-1) and direction. In September 1997, the mature ring was examined near 31°S, 9°E. By this time, its available heat and salt anomaly were reduced by about 30% and its available potential energy was reduced by about 70%. This indicates that a significant loss of the ring characteristics occurred on the way from the southern to the northern Cape Basin. One-third of this loss is due to changes at intermediate depth (between 800 and 1600 m).

Schott, F.A., M. Dengler, P. Brandt, K. Affler, J. Fischer, B. Bourles, Y. Gouriou, R.L. Molinari, and M. Rhein. The zonal currents and transports at 35 W in the tropical Atlantic. Geophysical Research Letters, 30(7):1349, doi:10.1029/2002GL016849 (2003).

The total of 13 existing cross-equatorial shipboard current profiling sections taken during the WOCE period between 1990 and 2002 along 35°W are used to determine the mean meridional structure of the zonal top-to-bottom circulation between the Brazilian coast, near 5°S, and 5°N and to estimate mean transports of the individual identified shallow, intermediate and deep current branches. One of the results is that, on the equator, a mean westward Equatorial Intermediate Current below the Equatorial Undercurrent exists.

Snowden, D.P., and R.L. Molinari. Subtropical cells in the Atlantic Ocean: An observational summary. In Interhemispheric Water Exchange in the Atlantic Ocean, G.J. Goni and P. Malanotte-Rizzoli (eds.). Elsevier Oceanography Series, 68 (ISBN 0444512675), 287-312 (2003).

In this paper, we survey the observational literature pertaining to the shallow meridional overturning circulation cells connecting the subduction regions of the subtropical North and South Atlantic Ocean with the upwelling regions on and near the equator. These subtropical cells (STCs) exist in both hemispheres, but they are not symmetric about the equator. The southern hemisphere STC has a structure consistent with the cannonical feature (i.e., subduction in the southern hemisphere subtropics, transport of the subducted water to the Equatorial Undercurrent, upwelling on the equator, and return of the upwelled water to the subtropics). However, there is no clear evidence to indicate that water subducted in the northern hemisphere subtropics reaches the equator. Rather, pathways of water subducted in the subtropical North Atlantic have been observed to the North Equatorial Countercurrent. Upwelling regions for these northern hemisphere water masses are not yet defined. Characteristics of the STCs which must be more fully explored (e.g., temporal variability, transports, mixing) in order to understand their impacts on the regional climate variability of the tropical Atlantic Ocean are identified.

Thacker, W.C. Data-model-error compatibility. Ocean Modelling, 5(3):233-247 (2003).

During data assimilation, differences between observations and their model counterparts should be consistent with the error statistics that govern how the model is to be corrected. The concept of incompatibility distance between observations and their model counterparts is introduced as a way of detecting inconsistencies, and formulae are presented for estimating the probability of encountering greater incompatibility. Observations can be examined one-by-one to insure that their confidence intervals are not widely separated from those of the model counterparts. They can be further examined in pairs to detect whether contrasts across fronts are consistent with assumptions about error correlations.

Tokarczyk, R., K.D. Goodwin, and E.S. Saltzman. Methyl chloride and methyl bromide degradation in the Southern Ocean. Geophysical Research Letters, 30(15):1808, doi:10.1029/2003GL017459 (2003).

This study presents shipboard measurements of the loss rate constants of methyl bromide and methyl chloride in surface seawater in the Southern Ocean, using a ¹³C stable isotope incubation technique. The measurements were made during October-December 2001, on a cruise track extending from Hobart, Tasmania to Buchanan Bay (Mertz Glacier) at the coast of Antarctica (46-67°S, 138-145°E). Significant loss rates were measured for both compounds, even in very cold waters where chemical loss rates were negligible. These observations are attributed to biological uptake, and they explain the tendency for high latitude waters to be undersaturated with respect to atmospheric methyl bromide and methyl chloride. These observations are the first open ocean measurements demonstrating the biological degradation of methyl chloride.

Tokarczyk, E.S. Saltzman, R.M. Moore, and S.A. Yvon-Lewis. Biological degradation of methyl chloride in coastal seawater. Global Biogeochemical Cycles, 17(2):1057, doi:10.1029/2002GB001949 (2003).

Methyl chloride (CH₃Cl) is the most abundant halocarbon in the atmosphere, and constitutes a significant fraction of the total atmospheric halogen burden. Chemical reactions of CH₃Cl in seawater are slow, and it has been believed that the oceans are not an important sink for this compound. However, direct measurements of CH₃Cl degradation rates in coastal seawater (Bedford Basin, Nova Scotia), using a stable isotope incubation technique, indicate rapid loss attributed to microbial activity. A series of weekly measurements from March 2000 to May 2001 yielded degradation rates ranging from 0-30% d^-1, with an annual mean of 7.4% d^-1. If biological uptake of CH₃Cl occurs throughout the oceans at similar rates, the mean partial atmospheric lifetime of CH₃Cl with respect to oceanic removal could be a few years, rather than several decades as previously thought. This rapid removal would make the oceans a major sink for CH₃Cl and lower the overall atmospheric lifetime of CH₃Cl from the current estimate of 1.3 to about 1.0 years. Measurements of the degradation rate of CH₃Cl in open ocean waters are needed in order to quantify the oceanic uptake rate.

Trinanes, J.A., and G.J. Goni. A web application to distribute and visualize altimeter-related products. AVISO Newsletter, 9:21-22 (2003).

No abstract.

Trinanes, J.A., and G.J. Goni. Implementation of a multi-scale system for environmental data distribution. In Remote Sensing of Fisheries and Prediction of Toxic Tides, F. Pose (ed.). Institute of University Studies, Spain, 79-111 (2003).

No abstract.

Uhlhorn, E.W., and P.G. Black. Verification of remotely sensed sea surface winds in hurricanes. Journal of Atmospheric and Oceanic Technology, 20(1):99-116 (2003).

Surface winds in hurricanes have been estimated remotely using the Stepped-Frequency Microwave Radiometer (SFMR) from the NOAA WP-3D aircraft for the past 15 years. Since the use of the GPS dropwindsonde system in hurricanes was first initiated in 1997, routine collocated SFMR and GPS surface wind estimates have been made. During the 1998, 1999, and 2001 hurricane seasons, a total of 249 paired samples were acquired and compared. The SFMR equivalent 1-min mean, 10-m level neutral stability winds were found to be biased high by 2.3 m s^-1 relative to the 10-m GPS winds computed from an estimate of the mean boundary layer wind. Across the range of wind speeds from 10 to 60 m s^-1, the rms was 3.3 m s^-1. The bias was found to be dependent on storm quadrant and independent of wind speed, a result that suggests a possible relationship between microwave brightness temperatures and surface wave properties. Tests of retrieved winds' sensitivities to sea surface temperature, salinity, atmospheric thermodynamic variability, and surface wind direction indicate wind speed errors of less than 1 m s^-1 above 15 m s^-1.

Wallace, D.W.R., and R.H. Wanninkhof. Ocean-atmosphere exchange and earth-system biogeochemistry. In Marine Science Frontiers for Europe, G. Wefer, F. Lamy, and F. Mantoura (eds.). Springer, Berlin, 107-129 (2003).

No abstract.

Wang, C., and D.B. Enfield. A further study of the tropical Western Hemisphere warm pool. Journal of Climate, 16(10):1476-1493 (2003).

Variability of the tropical Western Hemisphere warm pool (WHWP) of water warmer than 28.5°C, which extends seasonally over parts of the eastern North Pacific, the Gulf of Mexico, the Caribbean, and the western tropical North Atlantic (TNA), was previously studied by Wang and Enfield using the da Silva data from 1945-1993. Using additional datasets of the NCEP-NCAR reanalysis field and the NCEP SST from 1950-1999, and the Levitus climatological subsurface temperature, the present paper confirms and extends the previous study of Wang and Enfield. The WHWP alternates with northern South America as the seasonal heating source for the Walker and Hadley circulations in the Western Hemisphere. During the boreal winter a strong Hadley cell emanates northward from the Amazon heat source with subsidence over the subtropical North Atlantic north of 20°N, sustaining a strong North Atlantic anticyclone and associated northeast (NE) trade winds over its southern limb in the TNA. This circulation, including the NE trades, is weakened during Pacific El Ni�o winters and results in a spring warming of the TNA, which in turn induces the development of an unusually large summer warm pool and a wetter Caribbean rainy season. As the WHWP develops in the late boreal spring, the center of tropospheric heating and convection shifts to the WHWP region, whence the summer Hadley circulation emanates from the WHWP and forks into the subsidence regions of the subtropical South Atlantic and South Pacific. During the summers following El Ni�o, when the warm pool is larger than normal, the increased Hadley flow into the subtropical South Pacific reinforces the South Pacific anticyclone and trade winds, probably playing a role in the transition back to the cool phase of ENSO. Seasonally, surface heat fluxes seem to be primarily responsible for warming of the WHWP. Interannually, all of the data sets suggest that a positive ocean-atmosphere feedback through longwave radiation and associated cloudiness seems to operate in the WHWP. During the winter preceding a large warm pool, there is a strong weakening of the Hadley cell that serves as a "tropospheric bridge" for transferring El Ni�o effects to the Atlantic sector and inducing warming of the warm pool. Associated with the warm SST anomalies is a decrease in sea level pressure anomalies and an anomalous increase in atmospheric convection and cloudiness. The increase in convective activity and cloudiness results in less longwave radiation loss from the sea surface, which then reinforces SST anomalies. This data-inferred hypothesis of the longwave radiation feedback process needs to be further investigated for its validation in the WHWP.

Wanninkhof, R.H., T.-H. Peng, B. Huss, C.L. Sabine, and K. Lee. Comparison of inorganic carbon system parameters measured in the Atlantic Ocean from 1990 to 1998 and recommended adjustments. Oak Ridge National Laboratory Data Report, ORNL/CDIAC-140, 43 pp. (2003).

As part of the global synthesis effort sponsored by the Global Carbon Cycle project of the National Oceanic and Atmospheric Administration (NOAA) and U.S. Department of Energy, a comprehensive comparison was performed of inorganic carbon parameters measured on oceanographic surveys carried out under the auspices of the Joint Global Ocean Flux Study and related programs. Many of the cruises were performed as part of the World Hydrographic Program of the World Ocean Circulation Experiment and the NOAA Ocean-Atmosphere Carbon Exchange Study. Total dissolved inorganic carbon (DIC), total alkalinity (TAlk), fugacity of CO₂, and pH data from 23 cruises were checked to determine whether there were systematic offsets of these parameters between cruises. The focus was on the DIC and TAlk state variables. Data quality and offsets of DIC and TAlk were determined by using several different techniques. One approach was based on crossover analyses, where the deep-water concentrations of DIC and TAlk were compared for stations on different cruises that were within 100 km of each other. Regional comparisons were also made by using a multiple-parameter linear regression technique in which DIC or TAlk was regressed against hydrographic and nutrient parameters. When offsets of greater than 4 µmol/kg were observed for DIC and/or 6 µmol/kg were observed for TAlk, the data taken on the cruise were closely scrutinized to determine whether the offsets were systematic. Based on these analyses, the DIC data and TAlk data of three cruises were deemed of insufficient quality to be included in the comprehensive basinwide data set. For several of the cruises, small adjustments in TAlk were recommended for consistency with other cruises in the region. After these adjustments were incorporated, the inorganic carbon data from all cruises, along with hydrographic, chlorofluorocarbon, and nutrient data, were combined as a research-quality product for the scientific community.

Willoughby, H.E. A century of progress in tracking and warning: Improvements in observations, models, and forecasts. In Hurricane! Coping with Disaster: Progress and Challenges since Galveston, 1900, R.H. Simpson, R.A. Anthes, M. Garstang, and J. Simpson (eds.). American Geophysical Union, Special Publication Series 55 (ISBN 0-87590-297-9), 205-216 (2003).

No abstract. **2002**

Aberson, S.D. Operational targeting of hurricane tracks in the Atlantic: Processes and procedures. Proceedings, Second Workshop on Landfalling Typhoons in the Taiwan Area, Taipei, Taiwan, April 25-26, 2002. National Science Council, 53-67 (2002).

NOAA has been conducting operational targeting of dropwindsonde observations to improve tropical cyclone track forecasts since 1997. During the first two years, however, the impact of the observations was minimal, with only a slight improvement in track forecasts. However, with improvements to models, data assimilation, and targeting techniques, the forecasts for Hurricane Michelle in late 2001 were improved by 45 to 60% in the NCEP global model. This talk will present the basic premise behind targeting and the various targeting techniques available, and the process used in the U.S. to accomplish the targeting missions.

Aberson, S.D. Tropical cyclone track predictability limits. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 220-221 (2002).

No abstract.

Aberson, S.D. Two years of operational hurricane synoptic surveillance. Weather and Forecasting, 17(5):1101-1110 (2002).

In 1997, the National Hurricane Center and the Hurricane Research Division began operational synoptic surveillance missions with the Gulfstream IV-SP jet aircraft to improve the numerical guidance for hurricanes that threaten the continental United States, Puerto Rico, the Virgin Islands, and Hawaii. During the first two years, 24 missions were conducted. Global positioning system dropwindsondes were released from the aircraft at 150-200 km intervals along the flight track in the environment of each tropical cyclone to obtain profiles of wind, temperature, and humidity from flight level (nearly 150 hPa) to the surface. The observations were processed and formatted aboard the aircraft and sent to NCEP to be ingested into the Global Data Assimilation System, which subsequently served as initial and boundary conditions for a number of numerical models that forecast the track and intensity of tropical cyclones. The current study is an attempt to mimic this process to assess the impact of these operational missions on the numerical guidance. Although the small number of missions flown in 1997 showed error reductions of as much as 32%, the improvements seen in the two-year sample are not promising. The additional dropwindsonde data from the synoptic surveillance missions provided statistically significant improvements in the GFDL forecasts only at 12 h. The "VBAR" and Global Forecast System (AVN) forecasts were not significantly improved at any forecast time. Further examination suggests that the AVN synthetic vortex procedure, combined with difficulty in the quantification of the current storm-motion vector operationally, may have caused the mediocre improvements. Forecast improvements of 14-24% in GFDL forecasts are shown in the subset of cases in which the synthetic vortex data do not seem to be a problem. Improvements in the landfall forecasts are also seen in this subset of cases. A reassessment of tropical cyclone vortex initialization schemes used by forecast centers and numerical modelers may be necessary.

Asher, W., J. Edson, W.R. McGillis, R.H. Wanninkhof, D.T. Ho, and T. Litchendorf. Fractional area whitecap coverage and air-sea gas transfer velocities measured during GasEx-98. In Gas Transfer at Water Surfaces, M.A. Donelan, W.M. Drennan, E.S. Saltzman, and R.H. Wanninkhof (eds.). AGU Geophysical Series, Volume 127 (ISBN 0875909868), 199-203 (2002).

GasEx-98 was an air-sea exchange process cruise conducted aboard the NOAA ship Ronald H. Brown in the North Atlantic during May and June of 1998. During the cruise, air-sea gas transfer velocities for carbon dioxide were measured using the direct-covariance method. Because the sampling times for the covariance method are on the same order as the time scales of changes in meteorological forcing, the GasEx-98 results provide a unique data set for investigating whether changes in different forcing mechanisms correlate with changes in gas transfer. In particular, fractional area whitecap coverage, W_C, was measured during daylight hours using a dual-camera video system mounted on a bow tower. Several high wind speed events occurred during the cruise, and the resulting correlation between wind speed and W_C is consistent with previous oceanic measurements. The whitecap coverage data were combined with the wind speed records and these data were used in a parameterization of whitecap-mediated gas transfer to predict transfer velocities. These predicted transfer velocities are in good agreement with the transfer velocities derived from the direct-covariance data.

Atlas, D., C.W. Ulbrich, and F.D. Marks. Reply to comment by S.E. Yuter and R.A. Houze, Jr. "On partitioning tropical oceanic convective and stratiform rains by draft strength." Journal of Geophysical Research, 107(D1):4006, doi:10.1029/2001JD000658 (2002).

No abstract.

Bauer, S., M.S. Swenson, and A. Griffa. Eddy mean flow decomposition and eddy diffusivity estimates in the tropical Pacific Ocean: 2. Results. Journal of Geophysical Research, 107(C10):3154, doi:10.1029/2000JC000613 (2002).

Eddy diffusivity of the surface velocity field in the tropical Pacific Ocean was estimated using satellite-tracked drifting buoys (1979 through mid-1996). The tropical Pacific surface current system is characterized by nonstationarity, strong meridional shear, and an energetic mesoscale velocity field. Eddy diffusivity may be defined as the integral of the autocovariance of Lagrangian eddy velocities, requiring both stationary and homogeneous statistics of the eddy field. Eddy velocities were obtained by removing a splined mean field to eliminate mean shear from observations binned (1) spatially to group data that have similar dispersion characteristics and (2) temporally to create stationary eddy statistics. Zonal diffusivity estimates are up to seven times larger than meridional diffusivity estimates in the high eddy energy regions. This anisotropy is associated with the meridional mesoscale wave motion (i.e., by equatorial and tropical instability waves) that increases eddy variance but does not lead to a proportional increase in water parcel diffusion because of the coherent character of the trajectory motion, at least for initial time lags. Simple autoregressive models of first and second order are used to describe and classify the resulting eddy statistics. An independent confirmation of the diffusivity estimate in the central/eastern Pacific was obtained by comparing tracer flux divergence computed from a parameterization using diffusivity estimates of our analysis with that from direct eddy Reynolds stress flux divergence. Our results show that diffusivity can be estimated for regions not considered previously either because of sparse data or the complexities of the velocity field.

Bender, M., S. Doney, R.A. Feely, I. Fung, N. Gruber, D.E. Harrison, R. Keeling, J.K. Moore, J. Sarmiento, E. Sarachik, B. Stephens, T. Takahashi, P. Tans, and R.H. WANNINKHOF. A large-scale CO₂ observing plan: In situ oceans and atmosphere (LSCOP). NOAA/OAR Special Report (PB2003-100377), 201 pp. (2002).

This report recommends a strategy for making observations of carbon dioxide (CO₂) and related properties in the atmosphere and oceans, over large spatial scales and long timescales. It also recommends process studies of air-sea gas exchange, in order to obtain more accurate estimates of CO₂ transfer between the atmosphere and oceans. Models are essential tools for understanding the distributions and fluxes of CO₂ in the atmosphere and oceans. We recommend observations and modeling efforts to enhance the skills of models used for this purpose. An ultimate product of the observations, modeling efforts, and complementary process studies will be improved projections of the trajectory of the atmospheric CO₂ increase. The report's recommendations are summarized in Table E-1. These recommendations are prepared in the context of the U.S. Carbon Cycle Science Plan (CCSP), with the goal of advancing our ability to address the two fundamental questions that the CCSP posed: (1) what has happened to the carbon dioxide that has already been emitted by human activities (past anthropogenic CO₂); and (2) what will be the future atmospheric CO₂ concentration trajectory resulting from both past and future emissions? The importance of answering these questions is evident. A recent National Research Council report, Climate Change Science, documents the consensus scientists have reached that human emissions of greenhouse gases are increasingly affecting world climate. The President's speech to the nation on global climate change expressed concern about greenhouse warming at the highest levels of government and committed the United States to confront the issue. These documents recommend conducting the research necessary to understand the environmental behavior of biogenic greenhouse gases, of which carbon dioxide is the most significant. This research will lead toward the knowledge required to accurately project carbon removal rates from the atmosphere to the land biosphere and the oceans. This report presents a plan for large-scale U.S.-sponsored observations of CO₂ in the oceans and atmosphere. This plan represents an implementation plan for the CO₂ observations component of the CCSP. We recommend observations to track the fate of fossil fuel-derived CO₂, to characterize fluxes of CO₂ from the atmosphere to the land biosphere and oceans over large scales of space and time, and to achieve process-level understanding of physical and biological controls on those fluxes now and in the future. Complementary small-scale process studies of the land and ocean biospheres are needed for a comprehensive understanding of carbon fluxes and distributions. No specific recommendations for such programs are offered here, because they are being planned independently.

Bentamy, A., K.B. Katsaros, W.M. Drennan, and E.B. Forde. Daily surface wind fields produced by merged satellite data. In Gas Transfer at Water Surfaces, M.A. Donelan, W.M. Drennan, E.S. Saltzman, and R.H. Wanninkhof (eds.). AGU Geophysical Monograph Series, Volume 127 (ISBN 0875909868), 343-349 (2002).

Surface wind speed is the dominant variable over most of the ocean for the magnitude of air-sea exchange of trace gases, as well as wind stress, heat, and water vapor. Satellite data of surface winds are now produced routinely by scatterometers and radiometers on several satellites. Employing surface wind data from these various sensors and the Kriging technique with its associated variograms, which consider both space and time wind vector structures, we have produced 1° latitude by 1° longitude gridded wind fields over the global ocean on a daily basis. The present data set covers the period of the NASA scatterometer (NSCAT), September 1996 through June 1997. NSCAT data is merged with scatterometer data from the European Remote Sensing (ERS) satellite 2, and the wind speeds from two of the Special Sensor Microwave/Imagers (SSM/I) operating during that period. The accuracy of the resulting daily wind fields is determined by comparisons with moored-buoy wind speed and direction measurements, which are deployed and maintained by four different institutions in the Atlantic and Pacific Oceans. The root-mean-square (rms) difference values are less than 1.5 m/s. No significant difference was found between statistical parameters estimated over the equatorial zone and middle latitudes. To investigate the global patterns of these new satellite wind fields, comparisons with the National Environmental Prediction Center's (NCEP) re-analysis products have been carried out. The satellite data and the NCEP products have similar statistical error structure, but the merged wind fields provide complete coverage at much higher spatial resolution.

Berkelmans, R., J.C. Hendee, P.A. Marshall, P.V. Ridd, A.R. Orpin, and D. Irvine. Automatic weather stations: Tools for managing and monitoring potential impacts to coral reefs. Marine Technology Society Journal, 36(1):29-38 (2002).

With recent technological advances and a reduction in the cost of automatic weather stations and data buoys, the potential exists for significant advancement in science and environmental management using high-resolution, near real-time data to predict biological and/or physical events. However, real-world examples of how this potential wealth of data has been used in environmental management are few and far between. We describe in detail two examples where near real-time data are being used for the benefit of science and management. These include a prediction of coral bleaching events using temperature, light, and wind as primary predictor variables, and the management of coastal development where dynamic discharge quality limits are maintained with the aid of wind data as a proxy for turbidity in receiving waters. We argue that the factors limiting the use of near real-time environmental data in management are frequently not the availability of the data, but the lack of knowledge of the quantitative relationships between biological/physical processes or events and environmental variables. We advocate renewed research into this area and an integrated approach to the use of a wide range of data types to deal with management issues in an innovative, cost-effective manner.

Black, M.L., J.F. Gamache, F.D. Marks, C.E. Samsury, and H.E. Willoughby. Eastern Pacific Hurricanes Jimena of 1991 and Olivia of 1994: The effect of vertical shear on structure and intensity. Monthly Weather Review, 130(9):2291-2312 (2002).

Shear is a key inhibitor of tropical cyclone intensification. Although its signature is readily recognized in satellite imagery and theoretical or modeling studies provide some insight, detailed observations have been limited. Airborne radar and in-situ observations in Hurricanes Jimena of 1991 and Olivia of 1994 are a step toward better understanding. Each storm was observed on two consecutive days. Initially, both had small eyes, 16-18 km radius, and maximum winds of 57 m s^-1 over sea surface temperatures (SST) >28°C in easterly environmental shear. Jimena maintained constant intensity or weakened gradually for 2 days in 13-20 m s^-1 easterly shear. Olivia intensified in 8 m s^-1 shear on the first day. Overnight, the shear diminished to reverse and became westerly. On the second day, Olivia weakened as the shear increased to >15 m s^-1 from the west, the storm moved over cooler SST, and became surrounded by dryer air. As convection weakened and the outer rainbands ceased to be effective barriers, relative flow due to the environmental shear penetrated more deeply into the vortex core. In both storms, shear controlled the convective structure. Convection organized itself into axisymmetric rings as Olivia intensified in weak shear. When both storms encountered stronger shear, radar reflectivity and vertical motion had strong wavenumber-1 components. Highest reflectivity lay generally to the left of the shear. Most radar echoes and updrafts formed in the downshear quadrant of the storm and advected around the eye with 60-80% of the swirling wind, consistent with vortex Rossby wave propagation. The buoyant updrafts accelerated and reflectivity increased as they passed through the left-of-shear semicircle. On the upshear side, the updrafts rose through the 0°C isotherm, and hydrometeors fell out or froze. Reflectivity declined as the echoes transformed into lower-tropospheric downdrafts overlain by glaciated upper-tropospheric updrafts in the right-of-shear semicircle. In relatively weak shear, clusters of echoes could be tracked completely around the eye. Each time the clusters passed through the downshear and left-of-shear quadrants, new echoes would form. In strong shear, all echoes were short lived, and none could be tracked around the eye. Echoes appeared downshear of the center and completed their life cycles on the left side of the shear vector where the composite reflectivities were greatest.

Black, M.L., E.W. Uhlhorn, S.E. Feuer, W.P. Barry, and L.K. Shay. The relationship between GPS dropsonde wind profiles and sea-surface temperature in Hurricane Bret (1999). Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 551-552 (2002).

No abstract.

Black, R.A., and G.M. Heymsfield. Extra large particle images at 40,000 ft in a hurricane eyewall: Evidence of partially frozen raindrops? Preprints, 11th Conference on Cloud Physics, Ogden, UT, June 3-7, 2002. American Meteorological Society, Boston, 3 pp. (2002).

No abstract.

Bosart, L.F., P.G. Black, J.L. Evans, J.E. Molinari, C.S. Velden, and M.J. Dickinson. The double transition of Hurricane Michael (2000): Baroclinic to tropical to baroclinic. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 503-504 (2002).

No abstract.

Burpee, R.W., and P.G. Black. Ocean mixed layer thermal changes induced by moving tropical cyclones, Part I: Analyses of inner core observations obtained by research aircraft. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 571-572 (2002).

No abstract.

Cecil, D.J., G.M. Heymsfield, F.J. LaFontaine, M.G. Bateman, E.J. Zipser, and F.D. Marks. Precipitation structures observed in CAMEX hurricanes. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 63-65 (2002).

No abstract.

Chai, F., R.C. Dugdale, T.-H. Peng, F.P. Wilkerson, and R.T. Barber. One-dimensional ecosystem model of the equatorial Pacific upwelling system. Part I: Model development and silicon and nitrogen cycle. Deep-Sea Research, Part II, 49(13-14):2713-2745 (2002).

A one-dimensional ecosystem model was developed for the equatorial Pacific upwelling system, and the model was used to study the nitrogen and silicon cycle in the equatorial Pacific. The ecosystem model consisted of 10 components (nitrate, silicate, ammonium, small phytoplankton, diatom, micro- and meso-zooplankton, detrital nitrogen and silicon, and total CO₂). The ecosystem model was forced by the area-averaged (5°S-5°N, 90°W-180°, the Wyrtki Box) annual mean upwelling velocity and vertical diffusivity obtained from a three-dimensional circulation model. The model was capable of reproducing the low-silicate, high-nitrate, and low-chlorophyll (LSHNLC) conditions in the equatorial Pacific. The linkage to carbon cycle was through the consumption of assimilated nitrate and silicate (i.e., new productions). Model simulations demonstrated that low-silicate concentration in the equatorial Pacific limits production of diatoms, and it resulted in low percentage of diatoms, 16%, in the total phytoplankton biomass. In the area of 5°S-5°N and 90°W-180°, the model produced an estimated sea-to-air CO₂ flux of 4.3 mol m^-2 yr^-1, which is consistent with the observed results ranging of 1.0-4.5 mol m^-2 yr^-1. The ammonium inhibition played an important role in determining the nitrogen cycle in the model. The modeled surface nitrate concentration could increase by a factor of 10 (from 0.8 to 8.0 mmol m^-3) when the strength of the ammonium inhibition increased from psi = 1.0 to 10.0 (mmol m^-3)^-1. The effects of both micro- and meso-zooplankton grazing were tested by varying the micro- and meso-zooplankton maximum grazing rates, G1_max and G2_max. The modeled results were quite sensitive to the zooplankton grazing parameters. The current model considered the role of iron implicitly through the parameters that determine the growth rate of diatoms. Several iron-enrichment experiments were conducted by changing the parameter alpha (the initial slope of the photosynthetic rate over irradiance at low irradiance), K_Si(OH)4 (half-saturation concentration of silicate uptake by diatom), and µ2_max (the potential maximum specific diatom growth rate) in the regulation terms of silicate uptake by diatom. Within the first five days in the modeled iron-enrichment experiment, the diatom biomass increased from 0.08 to 2.5 mmol m^-3, more than a factor of 30 increase. But the diatom populations crashed two weeks after the experiment started, due to exhaustion of available silicate and increased mesozooplankton population. The modeled iron-enrichment experiments produced several ecological behaviors similar to these observed during the IronEx-2.

Chereskin, T.K., W.D. Wilson, and L.M. Beal. The Ekman temperature and salt fluxes at 8°30'N in the Arabian Sea during the 1995 southwest monsoon. Deep-Sea Research, Part II, 49(7-8):1211-1230 (2002).

The Arabian Sea Ekman transport is an important component of the meridional overturning circulation of the Indian Ocean. Chereskin et al. (Geophys. Res. Lett., 24 (1997), 2541) presented direct estimates of the Ekman transport across latitude 8°30'N in the Arabian Sea for June and September during the 1995 southwest monsoon. In this paper, we use these measurements to determine the Ekman depth and the resultant heat and salt fluxes. In June, at the monsoon onset, the Ekman temperature and salt fluxes were estimated to be southward, 2.4 ± 0.4 PW and 0.71 ± 0.1 × 10⁹ kgs^-1. The transport-weighted Ekman temperature and salinity were 29.0 ± 0.5°C and 35.31 ± 0.03 psu, not significantly different from surface values, 29.2°C and 35.28 psu, respectively. In September at the end of the monsoon, the Ekman temperature and salt fluxes had decreased in magnitude but were still southward, 0.77 ± 0.4PW and 0.27 ± 0.1 × 10⁹ kgs^-1. The transport-weighted temperature, 25.8 ± 0.5°C, was 1.1°C colder than the surface value, and the transport-weighted salinity, 35.83 ± 0.03 psu, was not significantly different from the surface value of 35.86 psu. For this pair of sections, the top of the pycnocline appeared to be a better approximation for the Ekman depth than either the mixed layer or a fixed depth, and our estimates of the Ekman heat and salt fluxes were integrated from the surface to the top of the pycnocline. Although uncertainty in the Ekman mass transport dominates the error in the Ekman heat and salt fluxes, determining the Ekman depth is also important in estimating the Ekman contribution to the heat budget of the tropical Indian Ocean. A decrease in Ekman temperature by 1.1°C resulted in a 5% decrease in the temperature transport estimated for September.

Cione, J.J., and E.W. Uhlhorn. Upper ocean heat content and energy extracted by the storm: Analytical look. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 631-632 (2002).

No abstract.

Cook, T.M., L.K. Shay, S.D. Jacob, C.W. Wright, P.G. Black, and E.W. Uhlhorn. Surface wave effects on the ocean mixed layer response to Hurricane Bonnie. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 633-634 (2002).

No abstract.

Dodge, P.P., M.L. Black, J.L. Franklin, J.F. Gamache, and F.D. Marks. High-resolution observations of the eyewall in an intense hurricane: Bret on 21-22 August 1999. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 607-608 (2002).

No abstract.

Donelan, M.A., and R.H. Wanninkhof. Gas transfer at water surfaces: Concepts and issues. In Gas Transfer at Water Surfaces, M.A. Donelan, W.M. Drennan, E.S. Saltzman, and R.H. Wanninkhof (eds.). AGU Geophysical Monograph Series, Volume 127 (ISBN 0875909868), 1-10 (2002).

This introductory paper puts the technical articles to follow in the context of the need to understand gas transfer at water surfaces and to apply improved methods to the estimation of the exchange of gases between air and water. We summarize the physical and chemical background to processes of interfacial gas transfer, discuss field and laboratory approaches to measuring the gas exchange rate, and to elucidating its causes. Finally, we illustrate the application of acquired understanding in gas transfer to the global flux of carbon dioxide. This issue is of societal relevance in predicting and possibly reducing anthropogenic causes of climate change.

Dugdale, R.C., R.T. Barber, F. Chai, T.-H. Peng, and F.P. Wilkerson. One-dimensional ecosystem model of the equatorial Pacific upwelling system. Part II: Sensitivity analysis and comparison with JGOFS EqPac data. Deep-Sea Research, Part II, 49(13-14):2747-2768 (2002).

A one-dimensional model of the equatorial Pacific upwelling ecosystem that incorporates two phytoplankton components, two grazers, and three nutrients, Si(OH)₄, NO₃, and NH₄ (Chai et al., Deep-Sea Res., II (2002) 2713-2745), was designed to consider the effects of Si(OH)₄ limitation on the diatom growth and ecosystem functioning. Model output was obtained for a range of source concentrations of Si(OH)₄, 3-15 mmol m^-3, coinciding with the range measured at 120 m depth during JGOFS EqPac. NO₃ was held at 12 mmol m^-3, reflecting the relatively greater concentrations of NO³ compared to Si(OH)₄ in the JGOFS data. The model was shown to function as a chemostat-like system with the loss rates, provided largely from zooplankton grazing, controlling growth rates of the phytoplankton. When different source concentrations of Si(OH)₄ were applied, surface concentrations of Si(OH)₄ varied within a narrow range compared to NO₃ as would occur in a chemostat with limiting Si(OH)₄ and non-limiting NO₃ in the feed water. Vertical profiles of nutrients compared well with field data. Model results are compared with field data for new and total nitrogen production and export of N, Si, and C, and with other models, although none consider Si(OH)₄ specifically. The model suggests that the stability of the equatorial system with its narrow range of biological and chemical variables is conferred by the action of diatoms providing food for mesozooplankton whose grazing also depletes the picoplankton. Diatoms increase with source Si(OH)₄ concentrations, and picoplankton population and NO₃ consumption decrease, resulting in a maximum surface TCO₂ and increased CO₂ flux to the atmosphere at intermediate source Si(OH)₄ concentrations. Diatoms function in the equatorial system as a silica pump to export silica. This means that sedimented biogenic silica under the equatorial upwelling area should be viewed as an amplifier of changes in surface properties, with important consequences to paleoequatorial productivity.

Dugdale, R.C., A.G. Wischmeyer, F.P. Wilkerson, R.T. Barber, F. Chai, M.-S. Jiang, and T.-H. Peng. Meridional asymmetry of source nutrients to the equatorial Pacific upwelling ecosystem and its potential impact on ocean-atmosphere CO₂ flux: A data and modeling approach. Deep-Sea Research, Part II, 49(13-14):2513-2531 (2002).

Si(OH)₄, NO₃, and TCO₂ are shown to be distributed asymmetrically in a north/south direction about the equatorial Pacific using data from WEPOCS III and JGOFS EqPac cruises. Equatorial SiOH₄ concentrations are shown to be the product of both geochemical and physical interactions with chemical processes occurring in at least three regions remote from the equatorial Pacific, and physical delivery processes from the equatorial undercurrent (EUC) to the surface layer varying over a range of time scales. The EUC was partitioned into upper and lower portions, the upper providing source water to the central upwelling area and the lower crossing the Pacific without upwelling and thought to reenter the surface along the coast of Peru and to the eastern equatorial upwelling area. The source waters from the North Pacific, the north equatorial countercurrent (NECC) and from the South Pacific, the New Guinea coastal undercurrent (NGCUC) also were partitioned according to source for the upper and lower EUC. Mean concentrations and ranges of nutrients for each source partition were obtained from field data. Current flow and advective data output from a three-dimensional physical model were used with the field nutrient data to calculate nutrient fluxes into the EUC. Although the inflow of water from the north and south were approximately equal, the stronger asymmetric distribution of Si(OH)₄ compared to NO₃ resulted in identifying the South Pacific source as only 30% of the total supply of Si(OH)₄ to the EUC and the cause of a low Si(OH)₄:NO₃ condition. These results suggest a coupling between Southern Ocean productivity, equatorial productivity, and the efflux of CO₂ to the atmosphere from the equatorial upwelling system.

Dunion, J.P., and M.D. Powell. Improvements to the NOAA Hurricane Research Division's surface reduction algorithm for inner core aircraft flight-level winds. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 581-582 (2002).

No abstract.

Dunion, J.P., and C.S. Velden. Application of surface-adjusted GOES low-level cloud-drift winds in the environment of Atlantic tropical cyclones. Part I: Methodology and validation. Monthly Weather Review, 130(5):1333-1346 (2002).

Beginning with the 1997 hurricane season, the Cooperative Institute for Meteorological Satellite Studies at the University of Wisconsin-Madison began demonstrating the derivation of real-time Geostationary Operational Environmental Satellite (GOES) low-level cloud-drift winds in the vicinity of Atlantic tropical cyclones. The winds are derived from tracking low-level clouds in sequential, high-resolution GOES visible channel imagery. Since then, these data have been provided to the National Oceanic and Atmospheric Administration (NOAA) Hurricane Research Division (HRD) for evaluation in their real-time tropical cyclone surface wind objective analyses (H*Wind) that are disseminated to forecasters at the NOAA National Hurricane Center on an experimental basis. These wind analyses are proving useful as guidance to support forecasters' tropical cyclone advisories and warnings. The GOES satellite wind observations often provide essential near-surface coverage in the outer radii of the tropical cyclone circulation where conventional in-situ observations (e.g., ships and buoys) are frequently widely spaced or nonexistent and reconnaissance aircraft do not normally fly. The GOES low-level cloud-tracked winds are extrapolated to the surface using a planetary boundary layer model developed at HRD for hurricane environments. In this study, the unadjusted GOES winds are validated against wind profiles from the newly deployed global positioning system dropwindsondes, and the surface-adjusted winds are compared with collocated in-situ surface measurements. The results show the ability of the GOES winds to provide valuable quantitative data in the periphery of tropical cyclones. It is also shown that the current scheme employed to extrapolate the winds to the surface results in small biases in both speed and direction. Nonlinear adjustments to account for these biases are presented.

Dunion, J.P., and C.S. Velden. Satellite applications for tropical wave/tropical cyclone tracking. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 132-133 (2002).

No abstract.

Dunion, J.P., and C.S. Velden. Satellite applications for tropical wave/tropical cyclone tracking. Preprints, 11th Conference on Satellite Meteorology and Oceanography, Madison, WI, April 29-May 3, 2002. American Meteorological Society, Boston, 314-317 (2002).

No abstract.

Dunion, J.P., S.H. Houston, C.S. Velden, and M.D. Powell. Application of surface adjusted GOES low-level cloud-drift winds in the environment of Atlantic tropical cyclones. Part II: Integration into surface wind analyses. Monthly Weather Review, 130(5):1347-1355 (2002).

The Cooperative Institute for Meteorological Satellite Studies at the University of Wisconsin-Madison recently (1997 season) began providing real-time Geostationary Operational Environmental Satellite (GOES) low-level cloud-drift winds in the vicinity of tropical cyclones on an experimental basis to the National Oceanic and Atmospheric Administration's (NOAA) Hurricane Research Division (HRD). The cloud-drift winds are derived from s equential high-resolution GOES visible channel imagery. These data were included in many of HRD's real-time tropical cyclone surface wind objective analyses, which were sent to NOAA's National Hurricane Center and the Central Pacific Hurricane Center on an experimental basis during the 1997-2001 hurricane seasons. These wind analyses were used to support the forecasters' tropical cyclone advisories and warnings. The satellite wind observations provide essential low-level coverage in the periphery of the tropical cyclone circulation where conventional in-situ observations (e.g., ships, buoys, and Coastal-Marine Automated Network stations) are often widely spaced or nonexistent and reconnaissance aircraft do not normally fly. Though winds derived from microwave channels on polar-orbiting satellites provide valuable surface wind data for HRD surface wind analyses, their swath coverage and orbital passes are limited spatially and temporally. GOES low-level visible (GLLV) winds offer nearly continuous spatial and temporal coverage in the western Atlantic and eastern Pacific basins. The GLLV winds were extrapolated to the surface using a planetary boundary layer model developed at HRD. These surface-adjusted satellite data were used in real-time surface wind analyses of 1998 Hurricane Georges, as well as in post-storm analyses of 1996 Hurricane Lili and 1997 Tropical Storm Claudette. The satellite observations often helped to define the spatial extent of the 17.5 m s^-1 (34 kt) surface wind radii and also redefined the 25.7 m s^-1 (50 kt) wind radius for one case. Examples of the impact of these data on real-time hurricane surface wind fields provided to the NHC will be discussed.

Eastin, M.D., P.G. Black, and W.M. Gray. Flight-level thermodynamic instrument wetting errors in hurricanes. Part I: Observations. Monthly Weather Review, 130(4):825-841 (2002).

Flight-level thermodynamic errors caused by the wetting of temperature and moisture sensors immersed within the airstream are studied using data from 666 radial legs collected in 31 hurricanes at pressure levels ranging from 850 to 500 mb. Concurrent measurements from a modified Barnes radiometer and a Rosemount 102 immersion thermometer are compared to identify regions, called instrument wetting events (IWE), in which Rosemount temperatures are significantly cooler than radiometer-derived temperatures by a specified amount. A total of 420 IWE are identified in the data set. Roughly 50% of the radial legs contain at least one instrument wetting event. More than 90% of IWE are associated with updrafts containing cloud water and are confined to scales less than 10 km. IWE are also found to be more frequent in eyewalls and intense hurricanes. Thermodynamic errors within IWE and convective updrafts and downdrafts are summarized as distributions of average temperature, specific humidity, virtual potential temperature, and equivalent potential temperature error. Distributions are skewed toward larger error values at all levels. Median average errors within IWE indicate that the thermodynamic quantities are typically too low by ~1°C, 1 g kg^-1, ~1.5 K, and ~5 K, respectively. The largest errors (>90% of the distribution) are nearly twice the median values. Error magnitudes tend to increase with height, but rarely achieve theoretical predictions. In addition, more than 65% of updrafts and 35% of downdrafts are found to contain significant thermodynamic errors. A correction method used in earlier studies was found to be inadequate at removing the majority of errors, but reduced the errors by 30%V50% on average.

Eastin, M.D., P.G. Black, and W.M. Gray. Flight-level thermodynamic instrument wetting errors in hurricanes. Part II: Implications. Monthly Weather Review, 130(4):842-851 (2002).

The implications of flight-level instrument wetting error removal upon the mean thermodynamic structure across the eyewall, buoyancy of rainband vertical motions, and vertical energy fluxes near the top of the inflow layer, are studied. Thermodynamic quantities across the mean eyewall are found to increase at all levels. As a result, maximum radial gradients of each quantity are shifted from the center of the eyewall cloud toward the outer edge. The increase in equivalent potential temperature lifts eyewall values to comparable magnitudes observed in the eye. The mean virtual potential temperature deviation of rainband updrafts increases from slightly negative to slightly positive. This increase and shift in sign are more pronounced in stronger updrafts. The mean deviation in rainband downdrafts decreases slightly toward neutral conditions. Vertical sensible heat fluxes near the top of the inflow layer are found to shift from downward to upward. Upward latent heat fluxes increase. Implications of these results upon hurricane structure and evolution are discussed.

Esenkov, O.E., and D.B. Olson. A numerical study of the Somali coastal undercurrents. Deep-Sea Research, Part II, 49(7-8):1253-1277 (2002).

Subsurface circulation in the western Arabian Sea is studied with an open boundary version of the Miami Isopycnic Coordinate Ocean Model (MICOM). The model solution demonstrates a strong annual cycle and significant alongshore variability of subsurface circulation. Based on the dynamics and water properties, three regions are identified along the coast. A cross-equatorial current, which exists throughout the year, carries low-salinity water northwards. Comparison of the model results with observations in the equatorial region demonstrates that the model reproduces the annual cycle and transport of the currents remarkably well. Although it underestimates the speed of the undercurrent core by about a factor of two, increasing the horizontal resolution from 0.35° to 0.225° improves agreement with the measurements. A spring southward undercurrent between 5°N and the equator owes its existence to the wind forcing in the Arabian Sea. Water with higher salinity values, found in the coastal region north of 5°N, is advected by a southward undercurrent that is present between October and March. The existence of the undercurrent is caused by flows from the east and northeast. The latter originates in the Persian Gulf and provides about 75% of water for the coastal undercurrent. The annual Rossby wave generated in the interior of the domain contributes to the formation of the current in the fall. The third region is an area near 4°N, where the southward undercurrent separates, as velocity and salinity fields suggest. Subsurface circulation north of 5°N is disconnected from flows near the equator during most of the year. The model circulation is not sensitive to the details of coastal bottom topography. In contrast, the presence of the Socotra Island, which is absent in the model, leads to a more realistic solution in that the southward undercurrent north of 5°N is present throughout the spring. Interannual variability of the model subsurface fields increases significantly when observed, rather than climatological, wind forcing is used. The most dramatic changes occur in the coastal and equatorial regions.

Etherton, B.J., and S.D. Aberson. Assimilation of GPS dropwindsonde data using a VICBAR ensemble. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 218-219 (2002).

No abstract.

Evans, J.L., C.S. Velden, L.F. Bosart, J.E. Molinari, and P.G. Black. Hurricane Michael: The "two-way TC." Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 505-506 (2002).

No abstract.

Feely, R.A., R.H. Wanninkhof, D.A. Hansell, M.F. Lamb, D. Greeley, and K. Lee. Water column CO₂ measurements during the GasEx-98 Expedition. In Gas Transfer at Water Surfaces, M.A. Donelan, W.M. Drennan, E.S. Saltzman, and R.H. Wanninkhof (eds.). AGU Geophysical Monograph Series, Volume 127 (ISBN 0875909868), 173-180 (2002).

During the recent GasEx-98 cruise in the North Atlantic aboard the NOAA ship Ronald H. Brown, carbon measurements were performed in the areas of 46°N, 20.5°W. This process study followed a warm core ring tagged with the deliberately introduced tracer, SF₆. Continuous surface water measurements were combined with vertical profiles sampled daily to depths up to 1000 m for carbon mass balance studies. Dissolved inorganic carbon (DIC) and fCO₂ measurements were conducted onboard in both underway and discrete analysis modes. During the 25-day experiment in the tagged patch surface water, fCO₂ values averaged 275 ± 9 µatm, providing a constant condition of undersaturation and flux of CO₂ into the ocean. Using the Wanninkhof (1992) exchange coefficient, the estimated CO₂ flux ranged from approximately 1-27 mol m^-2 yr^-1. The largest CO₂ flux occurred during a large wind event beginning on June 6. After the event, DIC and fCO₂ values decreased for a few days, as a result of increased productivity associated with the strong mixing event. The DIC results were combined with the TOC, TON, and nutrient data to provide a mass balance for carbon within the patch. The results for the 25-day period indicate DIC increases in the mixed layer ranging from 0.2-1.8 µmol kg^-1 d^-1 due to gas exchange.

Feely, R.A., C.L. Sabine, K. Lee, F.J. Millero, M.F. Lamb, D. Greeley, J.L. Bullister, R.M. Key, T.-H. Peng, A. Kozyr, T. Ono, and C.S. Wong. In-situ calcium carbonate dissolution in the Pacific Ocean. Global Biogeochemical Cycles, 16(4):1144, doi:10.1029/2002GB001866 (2002).

Over the past several years, researchers have been working to synthesize the WOCE/JGOFS global CO₂ survey data to better understand carbon cycling processes in the oceans. The Pacific Ocean data set has over 35,000 sample locations with at least two carbon parameters, oxygen, nutrients, CFC tracers, and hydrographic parameters. In this paper, we estimate the in-situ CaCO₃ dissolution rates in the Pacific Ocean water column. Calcium carbonate dissolution rates ranging from 0.01-1.1 mol kg^-1 yr^-1 are observed in intermediate and deep water beginning near the aragonite saturation horizon. In the North Pacific Intermediate Water between 400 and 800 m, CaCO₃ dissolution rates are more than seven times faster than observed in middle and deep water depths (average = 0.051 mol kg^-1 yr^-1). The total amount of CaCO₃ that is dissolved within the Pacific is determined by integrating excess alkalinity throughout the water column. The total inventory of CaCO₃ added by particle dissolution in the Pacific Ocean, north of 40°S, is 157 Pg C. This amounts to an average dissolution rate of approximately 0.31 Pg C yr^-1. This estimate is approximately 74% of the export production of CaCO₃ estimated for the Pacific Ocean. These estimates should be considered to be upper limits for in situ carbonate dissolution in the Pacific Ocean, since a portion of the alkalinity increase results from inputs from sediments.

Feely, R.A., J. Boutin, C.E. Cosca, Y. Dandonneau, J. Etcheto, H.Y. Inoue, M. Ishii, C. Le Quere, D.J. Mackey, M. McPhaden, N. Metzl, A. Poisson, and R.H. Wanninkhof. Seasonal and interannual variability of CO₂ in the equatorial Pacific. Deep-Sea Research, Part II, 49(13-14):2443-2469 (2002).

As part of the JGOFS field program, extensive CO₂ partial-pressure measurements were made in the atmosphere and in the surface waters of the equatorial Pacific from 1992 to 1999. For the first time, we are able to determine how processes occurring in the western portion of the equatorial Pacific impact the sea-air fluxes of CO₂ in the central and eastern regions. These eight years of data are compared with the decade of the 1980s. Over this period, surface-water pCO₂ data indicate significant seasonal and interannual variations. The largest decreases in fluxes were associated with the 1991-1994 and 1997-1998 El Ni�o events. The lower sea-air CO₂ fluxes during these two El Ni�o periods were the result of the combined effects of interconnected large-scale and locally forced physical processes: (1) development of a low-salinity surface cap as part of the formation of the warm pool in the western and central equatorial Pacific; (2) deepening of the thermocline by propagating Kelvin waves in the eastern Pacific; and (3) the weakening of the winds in the eastern half of the basin. These processes serve to reduce pCO₂ values in the central and eastern equatorial Pacific towards near-equilibrium values at the height of the warm phase of ENSO. In the western equatorial Pacific there is a small but significant increase in seawater pCO₂ during strong El Ni�o events (i.e., 1982-1983 and 1997-1998) and little or no change during weak El Ni�o events (1991-1994). The net effect of these interannual variations is a lower-than-normal CO₂ flux to the atmosphere from the equatorial Pacific during El Ni�o. The annual average fluxes indicate that during strong El Ni�os the release to the atmosphere is 0.2-0.4 Pg Cyr^-1 compared to 0.8-1.0 Pg Cyr^-1 during non-El Ni�o years.

Feuer, S.E., J.F. Gamache, M.L. Black, F.D. Marks, and J.B. Halverson. A multiple aircraft experiment in Hurricane Humberto (2001), Part I: Wind fields. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 206-207 (2002).

No abstract.

Fram, M.S., J.K. Berghouse, B.A. Bergamaschi, R. Fujii, K.D. Goodwin, and J.F. Clark. Water-quality monitoring and studies of the formation and fate of trihalomethanes during the third injection, storage, and recovery test at Lancaster, Antelope Valley, California, March 1998 through April 1999. U.S. Geological Survey, Open-File Report 02-102, 48 pp. (2002).

The U.S. Geological Survey, in cooperation with the Los Angeles County Department of Public Works and the Antelope Valley-East Kern Water Agency, conducted three cycles of injection, storage, and recovery tests to evaluate the feasibility of artificially recharging ground water in the Lancaster area of Antelope Valley, California. During the third cycle (March 1998 through April 1999), the tests included investigations of the formation and fate of trihalomethanes in the aquifer. Trihalomethanes are disinfection by-products formed by reaction between natural dissolved organic carbon that is present in water and chlorine that is added during the drinking-water-treatment process. This report includes a discussion of the design of the investigation; descriptions of the sampling, analytical, and experimental methods used in the investigation; and a presentation of the data collected. During the third cycle, 60 million gallons of chlorinated water was injected into the aquifer through well 7N/12W-27P2 in the Los Angeles County Department of Public Works well field in Lancaster between April 15 and June 16, 1998. One hundred fifty million gallons of water was extracted from the same well between June 30, 1998, and April 29, 1999. Water-quality samples were collected during the entire cycle from the well and from a nearby set of nested piezometers, and were analyzed for residual chlorine, dissolved organic carbon, trihalomethane, major anion, and dissolved solid concentrations; ultraviolet absorbance spectra; and a number of field water-quality parameters. A statistical analysis was done to evaluate the analytical precision of the residual chlorine, dissolved organic carbon, trihalomethane, and ultraviolet absorbance measurements on these samples. The formation of trihalomethanes in the injection water was examined in laboratory experiments: Trihalomethane concentrations in samples of injection water were monitored during a storage period, and trihalomethane formation potential in the presence of excess chlorine was measured. The role of mixing between injection water and ground water and the conservative or non-conservative behavior of trihalomethanes was studied by adding a conservative tracer, sulfur hexafluoride, to the injection water and monitoring its concentration in the extraction water. The potential for biodegradation of trihalomethanes by aquifer bacteria was assessed in laboratory experiments: Microcosms containing ground water or extraction water and sediment or concentrated bacteria were spiked with trihalomethanes, and the amount of trihalomethanes was monitored during an incubation period. The potential for sorption of trihalomethanes to aquifer sediments was assessed in laboratory experiments: Mixtures of sediment and water were spiked with trihalomethanes, and then the trihalomethane concentrations were measured after an equilibration period.

Gamache, J.F., P.D. Reasor, H.E. Willoughby, M.L. Black, and F.D. Marks. Observations of the evolution of precipitation and kinematic structure in a hurricane as it encountered strong westerly shear. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 547-548 (2002).

No abstract.

Goni, G.J., and M.O. Baringer. Surface currents in the tropical Atlantic across high density XBT line AX08. Geophysical Research Letters, 29(24):2218, doi:10.1029/2002GL015873 (2002).

Three temperature sections that cross the tropical Atlantic obtained from high density XBT transects are used to identify the major surface currents and to compute their water mass transports. The dynamic heights are computed using XBT temperature profiles with salinity derived from historical T-S relationships. The values of dynamic height estimated from altimeter data used in conjunction with climatological dynamic height fields are within 3 cm of the XBT-derived values. The error in XBT-derived dynamic height introduced by using historical T-S relationships instead of actual salinity values are estimated to be of the order of 1.5 cm. Dynamic height estimates using the actual salinity values underestimate those obtained using historical T-S relationships. The structure exhibited in the dynamic height and altimeter-derived sea height fields do not reveal all the upper ocean currents, making these temperature sections presented here critical for computing transports and identifying currents in this region.

Goni, G.J., P.G. Black, J.J. Cione, and L.K. Shay. Use of satellite altimetry to identify regions of hurricane intensification. Proceedings, 7th International Conference on Remote Sensing for Marine and Coastal Environments, Miami, FL, May 20-22, 2002. Veridian, Ann Arbor, MI, CD-ROM, 4 pp. (2002).

No abstract.

Harasti, P.R., W.-C. Lee, J.D. Tuttle, C.J. McAdie, P.P. Dodge, S.T. Murillo, and F.D. Marks. Operational implementation of single-Doppler radar algorithms for tropical cyclones. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 487-488 (2002).

No abstract.

Hendee, J.C., G. Liu, A. Strong, J. Sapper, D. Sasko, and C. Dahgren. Near real-time validation of satellite sea surface temperature products at Rainbow Gardens Reef, Lee Stocking Island, Bahamas. Proceedings, Seventh International Conference on Remote Sensing for Marine and Coastal Environments, Miami, FL, May 20-22, 2002. Veridian Systems Division, CD-ROM, 9 pp. (2002).

The National Oceanic and Atmospheric Administration's (NOAA) Coral Reef Watch program is installing in-situ monitoring stations at strategic coral reef areas for purposes of establishing long-term data sets, providing near real-time information products, and surface-truthing NOAA satellite sea surface temperature (SST) products used for coral bleaching predictions ("hot spots"). The suite of stations, which transmit data hourly, together with custom artificial intelligence software that analyzes the data, is called the Coral Reef Early Warning System (CREWS) network. At each CREWS station, local maintenance and calibration of the sea temperature sensor ensures high quality data. Local collaborators also provide feedback on the presence and progress of coral bleaching and thus validate coral bleaching predictions made by HotSpot and CREWS information products. Near Rainbow Gardens Reef, where the first CREWS station was installed, additional in-situ data loggers were deployed to compare with CREWS and satellite SST data for both the relatively shallow Great Bahama Bank and much deeper Exuma Sound. During summer 2001, CREWS successfully transmitted daily email satellite SST and in-situ temperature comparisons, which showed good agreement. Logger data were used to validate and interpret the satellite SST and CREWS station readings.

Heymsfield, G.M., J.B.Halverson, M.L. Black, F.D. Marks, E.J. Zipser, L. Tian, L. Belcher, P. Bui, and E. Im. Structure of the highly sheared Tropical Storm Chantal during CAMEX-4. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 202-203 (2002).

No abstract.

Hitchcock, G.L., P. Lane, S. Smith, J. Luo, and P.B. Ortner. Zooplankton spatial distributions in coastal waters of the northern Arabian Sea, August 1995. Deep-Sea Research, Part II, 49(12):2403-2423 (2002).

The spatial distribution of zooplankton biomass was surveyed in coastal waters of the northern Arabian Sea during the 1995 Southwest Monsoon (August) on cruise MB 95-06 of the NOAA Ship Malcolm Baldrige. Vertical patterns of displacement volumes from a limited set of paired day-night MOCNESS tows suggest there was little diel vertical migration in the coastal waters off the southern Arabian Peninsula. Zooplankton biomass varied from 5.2 to 15.1 gdwm^-2 (178-517 mMC m^-2) in the upper 200-300 m of Omani coastal waters. Distributions of acoustic backscatter were mapped in eight daytime acoustic Doppler current profiler transects in coastal waters off Oman and Somalia. Several transects contained maxima in acoustic backscatter that coincided with cool, fresh surface features that were several tens of kilometers wide. Although there was considerable scatter in the relationship between acoustically determined biomass (ADB) of zooplankton and surface temperature, there was a trend of increased biomass in the cool surface temperatures of the Omani upwelling zone. Acoustic transects crossed two filaments that extended seaward from upwelling centers off Oman and Somalia. Estimated zooplankton ADB exported from the upwelling zones in the surface features was on the order of 300 kgdws^-1. The physical and biological characteristics of filaments maintain zooplankton associated with upwelling areas, such as Calanoides carinatus, as they are advected offshore from coastal upwelling zones.

Houston, S.H., and M.D. Powell. Sensitivity study of HRD's H*WIND surface wind analyses for tropical cyclones. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 583-584 (2002).

No abstract.

Jiang, H., P.G. Black, E.W. Uhlhorn, P.A. Leighton, E.J. Zipser, and F.D. Marks. Optimal rain rate estimation in tropical cyclones: Validation of SFMR remote sensing rain rates. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 475-476 (2002).

No abstract.

Johns, W.E., T.L. Townsend, D.M. Fratantoni, and W.D. Wilson. On the Atlantic inflow to the Caribbean Sea. Deep-Sea Research, Part I, 49(2):211-243 (2002).

New observations are summarized that lead to the first comprehensive description of the mean inflow distribution in the passages connecting the Atlantic Ocean with the Caribbean Sea. The total Caribbean inflow of 28 Sv is shown to be partitioned approximately equally between the Windward Islands Passages (~10 Sv), Leeward Islands Passages (~8 Sv), and the Greater Antilles Passages (~10 Sv). These results are compared to a numerical model study using a six-layer, 1/4° resolution Atlantic Basin version of the NRL Layered Ocean Model. Results from two simulations are described, including a purely wind-forced model driven by Hellerman and Rosenstein (J. Phys. Oceanogr., 13:1093-1104, 1983) monthly winds, and a model with an additional 14 Sv meridional overturning cell driven by inflow/outflow ports at the northern (65°N) and southern (20°S) model boundaries. The purely wind-driven version of the model exhibits a total Caribbean inflow of 17 Sv, consistent with expectations from steady, non-topographic Sverdrup theory. Nearly all of the wind-driven inflow occurs north of Martinique at latitude ~15°N. The net transport through the Lesser Antilles passages south of 15°N (Grenada, St. Vincent, and St. Lucia passages) is nearly zero when the model is forced by winds alone. The addition of a 14 Sv meridional cell in the model increases the net Caribbean inflow to 28 Sv, with nearly all of the additional 11 Sv of inflow entering through the southern Lesser Antilles passages. The modeled inflow distribution resulting from the combined wind and overturning forced experiment is found to compare favorably with the observations. The seasonal cycle of the total inflow in the combined forcing experiment has a mixed annual/semiannual character with maximum in spring and summer and minimum in fall, with a total range of about 4 Sv. The seasonal cycle of the Florida Current resulting from this inflow variation is in good qualitative agreement with observations. Most of the seasonal inflow variation occurs through the Windward Islands passages in the far southern Caribbean, whose annual cycle slightly leads that of the Florida and Yucatan Currents. Variability of the modeled inflow on shorter time scales shows a dramatic change in character moving northward along the Antilles arc. The southern passages exhibit large fluctuations on 30-80 day time scales, which decay to very small amplitudes north of Dominica. Much of this variability is caused by North Brazil Current Rings that propagate northwestward from the equatorial Atlantic and interact with the abrupt island arc topography. The total range of transport variability in individual passages predicted by the model is consistent with observations. However, observations are presently too limited to confirm the seasonal cycles or variability spectra in the Caribbean passages.

Jones, R.W., and H.E. Willoughby. Nonlinear motion of a two-layer baroclinic hurricane in shear. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 134-135 (2002).

No abstract.

Jury, M.R., D.B. Enfield, and J.-L. Melice. Tropical monsoons around Africa: Stability of El Ni�o-Southern Oscillations associations and links with continental climate. Journal of Geophysical Research, 107(C10):3151, doi:10.1029/2000JC000507 (2002).

Interannual fluctuations of monsoons around Africa and the stability of associations with the El Ni�o-Southern Oscillation (ENSO) and African rainfall are studied. The statistical analysis employs sea surface temperature (SST), surface and upper winds, and surface pressure averaged over key monsoon areas of the tropical Atlantic and Indian Oceans. The time series span the period 1958-1998, and wavelet analysis is applied to localize relationships in time, as well as in frequency, and enable us to examine how the amplitude and time delay at interannual scales varies through the record. Comparisons are made with Ni�o3 SST and other known ENSO signals in the African hemisphere. It is found that upper zonal winds over the tropical Atlantic are an integral part of the global ENSO. Zonal winds are associated with SST changes in the equatorial east Atlantic, which are antiphase to those in the west-central Indian Ocean. A composite analysis of warm and cool events in the Indian Ocean reveals that evaporation, radiative fluxes, and wind curl interact constructively. Anticyclonic curl (depression of isotherms) leads warm events, while cool events may initiate from oceanic advection and are sustained by evaporative fluxes. Rainfall fluctuations across Africa are analyzed, and three coherent areas are identified: West (Sahel-Guinea), Southern (Kalahari-Zambezi), and East (Kenya-Tanzania). Multivariate regression algorithms are fitted to the continuous filtered rainfall series over the period 1958-1988. Using three monsoon indices in a multivariate model, about 40% of the variance is explained at zero lag. An influential variable for most African rainfall areas is the zonal wind over the tropical Atlantic. The north-south SST gradient in the tropical Atlantic modulates rainfall in West Africa as expected. At six-month lead, surface pressure in the north Indian Ocean is a key determinant for West African climate. For southern African rainfall, SST in the southwest Indian Ocean and monsoon indices in the west-central Indian Ocean play significant roles. East African rainfall fluctuations are linked with zonal winds in the east Indian Ocean. The findings address current Climate Variability and Predictability program (CLIVAR) priorities for understanding how continental climate interacts with ENSO and other regional modes of variability.

Kaplan, J., and M. DeMaria. Estimating the probability of rapid intensification using the SHIPS model output: Some preliminary results. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 124-125 (2002).

No abstract.

Katsaros, K.B. Hurricane research inside the storm. Atmosph�riques, 13:22-23 (2002).

No abstract.

Katsaros, K.B., E.B. Forde, A.M. Mestas-Nunez, and A. Bentamy. Wind and evaporation patterns in the tropical Pacific Ocean from satellite data. Proceedings, Sixth Pan Ocean Remote Sensing Conference (PORSEC), Bali, Indonesia, September 3-6, 2002. Agency for Marine and Fisheries Research, Volume 2, 527-533 (2002).

Using one year (October 1996-September 1997) of weekly sea surface temperatures (SSTs) determined from Advanced Very High Resolution Radiometer (AVHRR) data, gridded surface wind fields based on several satellite sensors, and estimates of surface humidity based on the Special Sensor Microwave/Imager (SSM/I), we examine the patterns of variability in wind and evaporation rate in the tropical Pacific Ocean during the months preceding the 1997-1998 El Ni�o. Enhanced surface wind and associated evaporation rates were found to occur for periods of a few weeks in the northern hemisphere trade wind region. The developing warming in the eastern Pacific Ocean eliminated the cool tongue gradually, such that it disappeared by July 2, 1997, and there was no longer a minimum in evaporation in that region. The enhanced strong evaporation associated with the Indian monsoon is clearly seen in the Bay of Bengal and the Arabian Sea during the week of June 16, 1997.

Katsaros, K.B., P.W. Vachon, W.T. Liu, and P.G. Black. Microwave remote sensing of tropical cyclones from space. Journal of Oceanography, 58:137-151 (2002).

This article reviews several microwave instruments employed in research and analysis of tropical cyclones (TCs), typhoons, and hurricanes. The instruments discussed include scatterometers, microwave radiometers, synthetic aperture radars (SAR), and rain radar from space. Examples of the particular contribution by one or more of these instruments in analysis of several storms illustrate the comprehensive new views provided by the SeaWinds scatterometers, the detailed high-resolution wind field provided by RADARSAT SAR, particularly inside and in the vicinity of hurricane "eyes," and the presence of secondary flows in the region between rainbands in TCs. The high spatial resolution of precipitation data from the Tropical Rainfall Measuring Mission's rain radar, combined with scatterometer or SAR data, give a significant improvement in the details that can be seen from space, at the surface, and in the precipitating areas of TCs. The microwave instruments provide the penetrating view below the upper level cirrus clouds.

Kiesling, T.L., E. Wilkinson, J. Rabalais, P.B. Ortner, M.M. McCabe, and J.W. Fell. Rapid identification of adult and naupliar stages of copepods using DNA hybridization methodology. Marine Biotechnology, 4(1):30-39 (2002).

Larval stages of common marine invertebrates and their ecological roles within their respective communities are frequently ignored because they are hard to identify. Morphological characters are often insufficient to differentiate between genera, much less species. To overcome the obstacles associated with species identification of copepod larvae, we developed a microtiter plate-based hybridization assay. Species-specific probes based on rDNA sequences were bound to microplates and used to capture target DNA. A novel method of linking the probes to the plate with poly-T tail ensured the probes were positioned above the plate surface and available for hybridization; this significantly increased the sensitivity of the assay. Target DNA extracted from individual copepods was amplified with biotin-labeled primers. The labeled target DNA bound to the probe specific for that species and produced a colorimetric change in the assay. The assay can be rapidly performed on freshly caught or ethanol preserved samples and the results visually interpreted.

King, D.B., J.H. Butler, S.A. Yvon-Lewis, and S.A. Cotton. Predicting oceanic methyl bromide saturation from SST. Geophysical Research Letters, 29(24):2199, doi:10.1029/2002GL016091 (2002).

Data collected from the North Pacific Ocean during September and October 1999 were combined with data from other cruises to assess seasonal differences in the relationships between sea surface temperature (SST) and methyl bromide (CH₃Br) saturation. We now are able to reproduce observed saturation anomalies substantially better with the revised, seasonal CH₃Br-SST equations than with those that were independent of season. The effect is most noticeable in temperate waters where data combined on an annual basis proved insufficient. The estimated, net global air-sea flux of CH₃Br remains negative at -10 to -18 Gg yr^-1, which is consistent with extrapolations from observations.

Kollias, P., B.A. Albrecht, and F.D. Marks. Why Mie? Bulletin of the American Meteorological Society, 83(10):1471-1483 (2002).

This article demonstrates an innovative method for the observation of vertical air motion and raindrop size distribution in precipitation using a 94-GHz Doppler radar. The method is particularly appealing since it is based on fundamental physics, the scattering of microwave radiation by large particles (Mie scattering). The technique was originally proposed in 1988 by Dr. Roger Lhermitte, who ironically pioneered the development of 94-GHz Doppler radars for the study of nonprecipitating clouds. Since then, no real effort for the evaluation and demonstration of the technique was undertaken. In this article, observations from stratiform rain are presented to illustrate the potential and accuracy of the method. The retrievals from this technique provide vertical air motion to an accuracy of 5-10 cm s^-1. Despite attenuation, the Doppler velocity measurements remain unbiased and the data revealed high-resolution kinematical and microphysical structures within the stratiform precipitation for the first time. This article will hopefully expose the potential of this technique to the meteorological community and will serve as another example of the visionary contributions that Dr. Lhermitte has made to radar meteorology.

Lamb, M.F., C.L. Sabine, R.A. Feely, R.H. Wanninkhof, R.M. Key, G.C. Johnson, F.J. Millero, K. LEE, T.-H. PENG, A. Kozyr, J.L. Bullister, D. Greeley, R.H. Byrne, D.W. Chipman, A.G. Dickson, C. Goyet, P.R. Guenther, M. Ishii, K.M. Johnson, C.D. Keeling, T. Ono, K. Shitashima, T. Tilbrook, T. Takahashi, D.W.R. Wallace, Y.W. Watanabe, C. Winn, and C.S. Wong. Consistency and synthesis of Pacific Ocean CO₂ survey data. Deep-Sea Research, Part II, 49(1-3):21-58 (2002).

Between 1991 and 1999, carbon measurements were made on 25 WOCE/JGOFS/OACES cruises in the Pacific Ocean. Investigators from 15 different laboratories and four countries analyzed at least two of the four measurable ocean carbon parameters (DIC, TAlk, fCO₂, and pH) on almost all cruises. The goal of this work is to assess the quality of the Pacific carbon survey data and to make recommendations for generating a unified data set that is consistent between cruises. Several different lines of evidence were used to examine the consistency, including comparison of calibration techniques, results from certified reference material analyses, precision of at-sea replicate analyses, agreement between shipboard analyses and replicate shore-based analyses, comparison of deep water values at locations where two or more cruises overlapped or crossed, consistency with other hydrographic parameters, and internal consistency with multiple carbon parameter measurements. With the adjustments proposed here, the data can be combined to generate a Pacific Ocean data set, with over 36,000 unique sample locations analyzed for at least two carbon parameters in most cases. The best data coverage was for DIC, which has an estimated overall accuracy of ~3 µmol kg^-1. TAlk, the second most common carbon parameter analyzed, had an estimated overall accuracy of ~5 µmol kg^-1. To obtain additional details on this study, including detailed crossover plots and information on the availability of the compiled, adjusted data set, visit the Global Data Analysis Project web site at http://cdiac.esd.ornl.gov/oceans/glodap.

Landsea, C.W., C. Anderson, N. Charles, G. Clark, J.P. Dunion, J. Fernandez-Partagas, P. Hungerford, C. Neumann, and M. Zimmer. The Atlantic hurricane database re-analysis project documentation for the 1851-1910 alterations and additions to the HURDAT database. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 460-461 (2002).

No abstract.

Lawrence, J.R., S.D. Gedzelman, J.F. Gamache, and M.L. Black. Stable isotope ratios: Hurricane Olivia. Journal of Atmospheric Chemistry, 41(1):67-82 (2002).

The oxygen and hydrogen isotopic compositions of rains from Hurricane Olivia (1994) in the eastern Pacific were measured. The rains were collected on 24 and 25 September during airplane flights conducted at an elevation of 3 km. Hurricane Olivia peaked in intensity to a category-4 storm between the two dates. Isotope ratios of rains from Hurricane Olivia were markedly lower (delta¹⁸O = -13.9 parts per thousand to -28.8 parts per thousand) than that of rain collected from a thunderstorm at an elevation of 2.3 km outside the influence of Olivia (delta¹⁸O = -3.8 parts per thousand). A distinct decrease in isotope ratios from the first day to the next (delta¹⁸O = -18.4 parts per thousand to V21.9 parts per thousand) in Hurricane Olivia was attributed to decreased updraft velocities and outflow aloft. This shifted the isotopic water mass balance so that fewer hydrometeors were lifted and more ice descended to flight level. A decrease in the average deuterium excess from the first day to the next (delta = 15.5 to 7.1 parts per thousand) was attributed to an increase in the relative humidity of the water vapor "source" area. We hypothesize that the "source" region for the rain was in the boundary layer near the storm center and that because the hurricane was at peak intensity prior to the second day the relative humidity was higher.

Lee, K., D.M. Karl, R. Wanninkhof, and J.-Z. Zhang. Global estimates of net carbon production in the nitrate-depleted tropical and subtropical oceans. Geophysical Research Letters, 29(19):1907, doi:10.1029/2001GL014198 (2002).

Nitrate availability is generally considered to be the limiting factor for oceanic new production and this concept is central in our observational and modeling efforts. However, recent time-series observations off Bermuda and Hawaii indicate a significant removal of total dissolved inorganic carbon (C_T) in the absence of measurable nitrate. Here we estimate net carbon production in nitrate-depleted tropical and subtropical waters with temperatures higher than 20°C from the decrease in the salinity normalized C_T inventory within the surface mixed layer. This method yields a global value of 0.8 � 0.3 petagrams of carbon per year (Pg C yr^-1, Pg = 10¹⁵ grams), which equates to a significant fraction (20-40%) of the recent estimates (20-4.2 Pg C yr^-1) of total new production in the tropical and subtropical oceans (Emerson et al., 1997; Lee, 2001). The remainder is presumably supported by upward flux of nutrients into the euphotic zone via eddy diffusion and turbulent mixing processes or lateral exchange. Our calculation provides the first global-scale estimate of net carbon production in the absence of measurable nitrate. We hypothesize that it is attributable to dinitrogen (N₂) fixing microorganisms, which can utilize the inexhaustible dissolved N₂ pool and thereby bypass nitrate limitation.

Li, Y.-H., and T.-H. Peng. Latitudinal change of remineralization ratios in the oceans and its implication for nutrient cycles. Global Biogeochemical Cycles, 16(4):1130, doi:10.1029/2001GB001828 (2002).

A new three-end-member mixing model is introduced to obtain remineralization ratios of organic matter in the water column. Remineralization ratios (P/N/C_org/-O₂) of organic matter in the deep water column change systematically from the northern Atlantic to the Southern Oceans, then to the equatorial Indian and the northern Pacific oceans, more or less along the global ocean circulation route of deep water. Average remineralization ratios of organic matter for the northern Atlantic Ocean are P/N/C_org/-O₂ = 1/(16 � 1)/(73 � 8)/(137 � 7), and for the Southern Oceans P/N/C_org/-O₂ = 1/(15 � 1)/(80 � 3)/(133 � 5). Those values are similar to the traditional Redfield ratios of P/N/C_org/-O₂ = 1/16/106/138 for marine plankton, except for the low C_org/P ratio. Average remineralization ratios for the equatorial Indian Ocean are P/N/C_org/-O₂ = 1/(10 � 1)/(94 � 5)/(130 � 7), and for the northern Pacific Ocean P/N/C_org/-O₂ = 1/(13 � 1)/(124 � 11)/(162 � 11). The apparent low N/P ratio for both ocean basins suggests that organic nitrogen was converted partly into gaseous N₂O and N₂ by bacteria through nitrification/denitrification processes in a low-oxygen or reducing microenvironment of organic matter throughout the oxygenated water column. The actual N/P ratio of remineralized organic matter is probably around 15 � 1. The -O₂/C_org ratio of remineralized organic matter also decreases systematically along the global ocean circulation route of deep water, indicating changes in relative proportions of biomolecules such as lipids, proteins, nucleic acids, and carbohydrates. No temporal trends of remineralization ratios are detected when comparing the results obtained by GEOSECS and WOCE data sets.

Lirman, D., D. Manzello, and S. Macia. Back from the dead: The resilence of Siderastrea radians to severe stress. Coral Reefs, 21(3):291-292 (2002).

No abstract.

Liu, Q., S.J. Lord, N. Surgi, H.L. Pan, and F.D. Marks. Hurricane initialization using reconnaissance data in GFDL hurricane forecast model. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 267-268 (2002).

No abstract.

Macdonald, A.M., M.O. Baringer, K. Lee, D.W. Wallace, and R.H. Wanninkhof. Subtropical Atlantic carbon transport. International WOCE Newsletter, 42:14-19 (2002).

No abstract.

Macdonald, A.M., R.H. Wanninkhof, M.O. Baringer, P.E. Robbins, and D.W. Wallace. Oceanic biogeochemical fluxes: A summary of the JGOFS portion of the WOCE/JGOFS Transport Workshop, Southampton, June 25-29, 2001. International WOCE Newsletter, 42:20-21 (2002).

No abstract.

Marks, F.D., G. Kappler, and M. DeMaria. Development of a tropical cyclone rainfall climatology and persistence (R-CLIPER) model. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 327-328 (2002).

No abstract.

Mayrinck, C.E., P.P. Dodge, F.D. Marks, S.H. Houston, and J.F. Gamache. Evolution of the coastal windfield during the landfall of Hurricane Floyd (1999). Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 337-338 (2002).

No abstract.

Meinen, C.S., D.S. Luther, D.R. Watts, K.L. Tracey, A.D. Chave, and J. Richman. Combining inverted echo sounder and horizontal electric field recorder measurements to obtain absolute velocity profiles. Journal of Atmospheric and Oceanic Technology, 19(10):1653-1644 (2002).

Profiles of absolute velocity are difficult to obtain in the ocean, especially over long periods of time at the same location. This paper presents a method of estimating full water column absolute horizontal velocity profiles as a function of time by combining historical hydrography with the measurements from two separate instruments, the inverted echo sounder (IES) and the horizontal electric field recorder (HEFR). Hydrography is used to construct temperature, salinity, and specific volume anomaly characteristics as functions of the independent variables pressure and seafloor-to-sea-surface round-trip acoustic travel time (tau). Each IES measured tau is combined with these two-dimensional characteristics to estimate the profile of specific volume anomaly, which then is integrated vertically to obtain profiles of geopotential height anomaly (DELTA-phi). Profiles of DELTA-phi from adjacent IES sites are differenced to yield vertical profiles of relative geostrophic velocity. Horizontal electric fields arising from the vertically averaged horizontal water velocity provide the requisite referencing of the IES-derived relative velocities. Comparisons are presented between HEFR+IES absolute velocities in the Southern Ocean near 51°S, 143.5°E and absolute velocities determined via hydrography, acoustic Doppler current profiler, and current meter.

Miller, L.G., and K.D. Goodwin. Halocarbon biogeochemistry. Biogeochemistry, 60(2):119-120 (2002).

No abstract.

Millero, F.J., D. Pierrot, K. Lee, R. Wanninkhof, R.A. Feely, C.L. Sabine, R.M. Key, and T. Takahashi. Dissociation constants for carbonic acid determined from field measurements. Deep-Sea Research, Part I, 49(10):1705-1723 (2002).

A number of workers have recently shown that the thermodynamic constants for the dissociation of carbonic acid in seawater of Mehrbach et al. are more reliable than measurements made on artificial seawater. These studies have largely been confined to looking at the internal consistency of measurements of total alkalinity (TA), total inorganic carbon dioxide (TCO₂) and the fugacity of carbon dioxide (fCO₂). In this paper, we have examined the field measurements of pH, fCO₂, TCO₂, and TA on surface and deep waters from the Atlantic, Indian, Southern and Pacific oceans to determine the pK₁, pK₂, and pK₂-pK₁. These calculations are possible due to the high precision and accuracy of the field measurements. The values of pK₂ and pK₂-pK₁ over a wide range of temperatures (-1.6-38°C) are in good agreement (within �0.005) with the results of Mehrbach et al. The measured values of pK₁ at 4°C and 20°C are in reasonable agreement (within �0.01) with all the constants determined in laboratory studies. These results indicate, as suggested by internal consistency tests, that the directly measured values of pK₁+pK₂ of Mehrbach et al. on real seawater are more reliable than the values determined for artificial seawater. It also indicates that the large differences of pK₂-pK₁ (0.05 at 20°C) in real and artificial seawater determined by different investigators are mainly due to differences in pK₂. These differences may be related to the interactions of boric acid with the carbonate ion. The values of pK₂-pK₁ determined from the laboratory measurements of Lee et al. and Lueker et al. at low fCO₂ agree with the field-derived data to �0.016 from 5°C to 25°C. The values of pK₂-pK₁ decrease as the fCO₂ or TCO₂ increases. This effect is largely related to changes in the pK₂ as a function of fCO₂ or TCO₂. The values of fCO₂ calculated from an input of TA and TCO₂, which require reliable values of pK₂-pK₁, also vary with fCO₂. The field data at 20°C has been used to determine the effect of changes of TCO₂ on pK₂ giving an empirical relationship: pK₂^TCO2 = pK₂-1.6 x 10^-4 (TCO₂-2050) which is valid at TCO₂ > 2050 µmol kg^-1. This assumes that the other dissociation constants such as K_B for boric acid are not affected by changes in TCO₂. The slope is in reasonable agreement with the laboratory studies of Lee et al. and Lueker et al. (-1.2 x 10^-4 to -1.9 x 10^-4). This equation eliminates the dependence of the calculated fCO₂ on the level of fCO₂ or TCO₂ in ocean waters (sigma = 29.7 µatm in fCO₂). An input of pH and TCO₂ yields values of fCO₂ and TA that are in good agreement with the measured values (�22.3 µatm in fCO₂ and �4.3 µmol kg^-1 in TA). The cause of the decrease in pK₂ at high fCO₂ is presently unknown. The observed inconsistencies between the measured and computed fCO₂ values may be accounted for by adding the effect of organic acid (~8 µmol kg^-1) to the interpretation of the TA. Further studies are needed to elucidate the chemical reactions responsible for this effect.

Molinari, R.L., R. Lusic, S.L. Garzoli, M.O. Baringer, and G.J. Goni. Benchmarks for Atlantic Ocean circulation. CLIVAR Exchanges, 7(3/4):6-9 (2002).

No abstract.

Mooers, C.N.K., L. Gao, W.D. Wilson, W.E. Johns, K.D. Leaman, H.E. Hurlburt, and T. Townsend. Initial concepts for IAS-GOOS. In Operational Oceanography: Implementation at the European and Regional Scales, N.C. Flemming, S. Vallerga, N. Pinardi, H.W.A. Behrens, G. Manzella, D. Prandle, and J.H. Stel (eds.). Elsevier, New York, 379-390 (2002).

The Intra-Americas Sea (IAS) (Caribbean Sea, Gulf of Mexico, Straits of Florida, and adjacent waters) is a semi-enclosed sea dominated by the throughflow of the Gulf Stream system that serves to link the physics, chemistry, ecology, and fisheries of the region. A regional GOOS, IAS-GOOS, has been conceived that exploits the geography and dynamics of the region. Euro-GOOS could play a role in the development of IAS-GOOS, as well as with IOCARIBE-GOOS and individual national coastal GOOS activities in the IAS.

Morrison, I.J., F.D. Marks, and S. Businger. WSR-88D observations of boundary layer rolls during hurricane landfall. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 341-342 (2002).

No abstract.

Murillo, S.T., W.-C. Lee, F.D. Marks, and P.P. Dodge. Examining structural changes and circulation center of Hurricane Danny (1997) using a single-Doppler radar wind retrieval technique. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 485-486 (2002).

No abstract.

Nogues-Paegle, J., C.R. Mechoso, R. Fu, E.H. Berbery, W.C. Chao, T.-C. Chen, K. Cook, A.F. Diaz, D.B. Enfield, R. Ferreira, A.M. Grimm, V. Kousky, B. Liebmann, J. Marengo, K. Mo, J.D. Neelin, J. Paegle, A.W. Robertson, A. Seth, C.S. Vera, and J. Zhou. Progress in Pan American CLIVAR research: Understanding the South American monsoon. Meteorologica, 27(1-2):3-32 (2002).

A review of recent findings on the South American Monsoon System (SAMS) is presented. SAMS develops over a large extension of land mass crossed by the equator with surface conditions that vary from the world's largest tropical forest in Amazonia to a high desert in the Altiplano. The high Andes mountains to the west effectively block air exchanges with the Pacific Ocean, but plentiful moisture transport from the Atlantic maintains intense precipitation that is strongest over central Brazil. There is also abundant precipitation over the subtropical plains of South America in association with moisture transport from tropical latitudes. Furthermore, midlatitude systems are important modulators of the tropical precipitation. The combination of all these factors results in a unique seasonal evolution of convection and rainfall. The findings presented emphasize the system's complexity, and highlight the importance of the South American continent as the core of atmospheric linkages with the adjacent oceans. A discussion on directions for research on SAMS is also presented. There are still outstanding questions on the relative roles played on the system evolution by the orography, local and remote heat sources, and sea surface temperature anomalies. Other remaining questions address the impact of Amazon-deforestation on water and energy cycles over the two largest river basins of South America (Amazon and La Plata).

Nuissier, O., R.F. Rogers, and F. Roux. An initialization technique using airborne Doppler radar observations for numerical simulations of Hurricane Bret (21-23 August 1999). Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 403-404 (2002).

No abstract.

Ooyama, K.V. The cubic-spline transform method: Basic definitions and tests in a 1D single domain. Monthly Weather Review, 130(10):2392-2415 (2002).

The purpose of the paper is to describe the technical details of a numerical method that combines the cubic-spline representation of spatial variables in a finite domain with the logistics of the spectral transform method for the time integration of nonlinear meteorological equations. The reason for developing the method lies in its application to two-way interacting nested models of the atmosphere. When compared with the gridpoint representation, the cubic-spline representation allows direct evaluation of derivatives in the model equations, and leads to a substantial reduction of shortwave dispersion of advecting and propagating waves. When compared with the Fourier spectral representation, the cubic B-splines as basis functions provide simple but exact means of implementing a variety of boundary conditions that are needed at the domain interfaces, as well as at natural boundaries. A sharp (sixth order) low-pass filter, which is built into the cubic-spline transform, effectively eliminates adverse nonlinear accumulation of small-scale errors near the resolution limit. These features, critically important to noise-free nesting, are defined and analyzed in this paper in the simpler context of a single 1D domain. The actual procedures for two-way interactive nesting will be presented in a subsequent paper.

Palmer, D.R. A parabolic approximation method with application to global wave propagation. Journal of Mathematical Physics, 43(4):1875-1905 (2002).

Motivated by the difficulty in using the splitting matrix method to obtain parabolic approximations to complicated wave equations, we have developed an alternative method. It is three dimensional, does not a priori assume a preferred direction or path of propagation in the horizontal, determines spreading factors, and results in equations that are energy conserving. It is an extension of previous work by several authors relating parabolic equations to the horizontal ray acoustics approximation. Unlike previous work, it applies the horizontal ray acoustics approximation to the propagator rather than to the Green's function or the homogenous field. The propagator is related to the Green's function by an integral over the famous "fifth parameter" of Fock and Feynman. Methods for evaluating this integral are equivalent to narrow-angle approximations and their wide-angle improvements. When this new method is applied to simple problems, it gives the standard results. In this paper, it is described by applying it to a problem of current interest: the development of a parabolic approximation for modeling global underwater and atmospheric acoustic propagation. The oceanic or atmospheric waveguide is on an Earth that is modeled as an arbitrary convex solid of revolution. The method results in a parabolic equation that is energy conserving and has a spreading factor that describes field intensification for antipodal propagation. Significantly, it does not have the singularities in its range-sliced version possessed by many parabolic equations developed for global propagation. We then discuss two extensions of the method; first to propagation along refracted geodesics and second to a description involving discrete, local, normal modes.

Peterson, R.E., P.G. Black, and V. Pudov. Russian/FSU tropical cyclone research: The last 25 years. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 513-514 (2002).

No abstract.

Powell, M.D., and S.D. Aberson. Accuracy of United States tropical cyclone landfall forecasts in the Atlantic basin, 1976-2001. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 301-302 (2002).

No abstract.

Reasor, P.D., and M.T. Montgomery. Understanding the dynamics of vertically sheared hurricanes. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 317-318 (2002).

No abstract.

Roemmich, D., Y. Desaubies, H. Freeland, R. Keeley, K. Kim, B. King, P.-Y. LeTraon, R.L. Molinari, B. Owens, S. Pouliquen, K. Radhakrishnan, S. Riser, U. Send. P. Sutton, K. Takeuchi, J. Xu, and S. Wijffels (Argo Science Team). Implementing Argo, the global profiling array. Proceedings, En Route to GODAE International Symposium, Biarritz, France, June 13-15, 2002. CNES, 7 pp. (2002).

The Argo Project (Argo Science Team, 2001) has entered its implementation phase, with over 400 active floats now in the water, and committed funding for 1500 floats. Emphasis is shifting from motivating and planning Argo to deploying floats, providing data to users, and demonstrating the value of the array while it grows. Challenges remain associated with the production and deployment of a global 3000 float array. Argo requires strong collaboration across its national programs, and the involvement of many additional nations in float deployment and utilization of Argo data. The long-term engagement of scientific expertise in Argo is also needed, along with a strong partnership between scientific and operational participants. The vast extent of the southern hemisphere oceans, where most of the floats will be distributed, is a further challenge. Argo was initiated under the joint auspices of CLIVAR and GODAE, to produce unprecedented broad-scale measurements of temperature, salinity, and ocean circulation for climate and other applications. The import of Argos simple premise that Global Ocean Data Assimilation requires global ocean data is about to be demonstrated.

Rogers, R.F., R.A. Black, and D.-L. Zhang. A preliminary investigation of a common microphysical parameterization and its applicability to tropical cyclone simulations. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 436-437 (2002).

No abstract.

Rogers, R.F., S.D. Aberson, J. Kaplan, and S.B. Goldenberg. A pronounced upper-tropospheric warm anomaly encountered by the NOAA Gulfstream-IV aircraft in the vicinity of deep convection. Monthly Weather Review, 130(1):180-187 (2002).

Recent flights near deep convection by the National Oceanic and Atmospheric Administration's Gulfstream-IV surveillance aircraft have occasionally experienced significant positive temperature anomalies that sometimes impact the aircraft performance. One such event occurred over the Bahamas on 23 August 1999. During a 20-s time period, when the plane was cruising at an altitude of 175 hPa, the flight-level ambient temperature rose 15°C and returned to ambient values, concurrent with significant fluctuations in the horizontal and vertical winds. Large temperature anomalies such as that reported here can cause the avionics on the aircraft to compensate with a sudden decrease in air speed and a loss of altitude. Possible explanations for this anomaly include instrument error and convectively forced gravity waves or upper-level subsidence.

Rogers, R.F., S. Chen, J.E. Tenerelli, and H.E. Willoughby. The role of vertical shear in determining the distribution of accumulated rainfall in high-resolution numerical simulations of tropical cyclones. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 319-320 (2002).

No abstract.

Rona, P.A., D.R. Jackson, K.G. Bemis, C.D. Jones, K. Mitsuzawa, D.R. Palmer, and D. Silver. Acoustic advances study of sea floor hydrothermal flow. EOS, Transactions, American Geophysical Union, 83(44):497, 501-502 (2002).

No abstract.

Sabine, C.L., R.A. Feely, R.M. Key, J.L. Bullister, F.J. Millero, K. Lee, T.-H. Peng, B. Tilbrook, T. Ono, and C.S. Wong. Distribution of anthropogenic CO₂ in the Pacific Ocean. Global Biogeochemical Cycles, 16(4):1083, doi:10.1029/2001GB001639 (2002).

This work presents an estimate of anthropogenic CO₂ in the Pacific Ocean based on measurements from the WOCE/JGOFS/OACES global CO₂ survey. These estimates used a modified version of the DELTA C* technique. Modifications include a revised preformed alkalinity term, a correction for denitrification, and an evaluation of the disequilibrium terms using an optimum multiparameter analysis. The total anthropogenic CO₂ inventory over an area from 120°E to 70°W and 70°S to 65°N (excluding the South China Sea, the Yellow Sea, the Japan/East Sea, and the Sea of Okhotsk) was 44.5 ± 5 Pg C in 1994. Approximately 28 Pg C was located in the Southern Hemisphere and 16.5 Pg C was located north of the equator. The deepest penetration of anthropogenic CO₂ is found at about 50°S. The shallowest penetration is found just north of the equator. Very shallow anthropogenic CO₂ penetration is also generally observed in the high-latitude Southern Ocean. One exception to this is found in the far southwestern Pacific where there is evidence of anthropogenic CO₂ in the northward moving bottom waters. In the North Pacific, a strong zonal gradient is observed in the anthropogenic CO₂ penetration depth with the deepest penetration in the western Pacific. The Pacific has the largest total inventory in all of the southern latitudes despite the fact that it generally has the lowest average inventory when normalized to a unit area. The lack of deep and bottom water formation in the North Pacific means that the North Pacific inventories are smaller than the North Atlantic.

Schaefer, J.K., K.D. Goodwin, I.R. McDonald, J.C. Murrell, and R.S. Oremland. Leisingera methylohalidivorans gen. nov., sp. nov., a marine methylotroph that grows on methyl bromide. International Journal of Systematic and Evolutionary Microbiology, 52(3):851-859 (2002).

A marine methylotroph, designated strain MB2T, was isolated for its ability to grow on methyl bromide as a sole carbon and energy source. Methyl chloride and methyl iodide also supported growth, as did methionine and glycine betaine. A limited amount of growth was observed with dimethylsulfide. Growth was also noted with unidentified components of the complex media marine broth 2216, yeast extract, and casamino acids. No growth was observed on methylated amines, methanol, formate, acetate, glucose, or a variety of other substrates. Growth on methyl bromide and methyl iodide resulted in their oxidation to CO₂ with stoichiometric release of bromide and iodide, respectively. Strain MB2T exhibits growth optima at NaCl and Mg₂⁺ concentrations similar to that of seawater. Phylogenetic analysis of the 16S rDNA sequences placed this strain in the alpha subgroup of the Proteobacteria in proximity with the Ruegeria and Roseobacter genera. We propose that strain MB2T be designated Leisingera methylohalidivorans, gen. nov., sp. nov. (ATCC accession number BAA-92).

Schecter, D.A., M.T. Montgomery, and P.D. Reasor. A theory for the vertical alignment of a quasigeostrophic vortex. Journal of the Atmospheric Sciences, 59(2):150-168 (2002).

This article presents a new theory for the rate at which a quasigeostrophic vortex realigns, under conservative dynamics, after being tilted by an episode of external vertical shear. The initial tilt is viewed as the excitation of a three-dimensional "vortex Rossby mode." This mode, that is, the tilt, decays exponentially with time during its early evolution. The decay rate, gamma, is proportional to the potential vorticity gradient at a critical radius, where the fluid rotation is resonant with the mode. The decay rate gamma also depends on the internal Rossby deformation radius l_R, which is proportional to the stratification strength of the atmospheric or oceanic layer containing the vortex. The change of gamma with l_R is sensitive to the form of the vortex. For the case of a "Rankine-with-skirt" vortex, the magnitude of gamma increases (initially) with increasing l_R. On the other hand, for the case of a "Gaussian" vortex, the magnitude of gamma decreases with increasing l_R. The relevance of this theory to tropical cyclogenesis is discussed.

Schecter, D.A., M.T. Montgomery, and P.D. Reasor. The vertical alignment of an incipient tropical cyclone. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 399-400 (2002).

No abstract.

Seki, M.P., R. Lumpkin, and P. Flament. Hawaii cyclonic eddies and blue marlin catches: The case study of the 1995 Hawaiian International Billfish Tournament. Journal of Oceanography, 58(5):739-745 (2002).

The combination of prevailing northeasterly tradewinds and island topography results in the formation of vigorous, westward propagating cyclonic eddies in the lee of the Hawaiian Islands on time scales of 50-70 days. These mesoscale (~10² km) features are nowhere more conspicuous or spin up more frequently than in the Alenuihaha Channel between the Island of Maui and the Big Island of Hawaii. Cyclonic eddies in subtropical waters such as those around Hawaii vertically displace the underlying nutricline into the overlying, nutrient-depleted euphotic zone creating localized biologically enhanced patches. Insight into how these eddies may directly influence pelagic fish distribution is provided by examination of recreational fish catch data coinciding with the presence of eddies on the fishing grounds. We highlight the 1995 Hawaii International Billfish Tournament in which a cyclonic eddy dominated the ocean conditions during the week-long event and the fish catch distribution differed significantly from the average historical tournament catch patterns. On the tournament fishing grounds, well-mixed surface layers and strong current flows induced by the eddy's presence characterized the inshore waters where the highest catches of the prized Pacific blue marlin (Makaira mazara) occurred, suggesting possible direct (e.g., physiological limitations) or indirect (e.g., prey availability) biological responses of blue marlin to the prevailing environment.

Sharp, R.J., M.A. Bourassa, J.J. O'Brien, K.B. Katsaros, and E.B. Forde. Early detection of tropical cyclones using SeaWinds-derived vorticity for the 2001 hurricane season. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 401-402 (2002).

No abstract.

Shay, L.K., S.D. Jacob, T.M. Cook, M.M. Mainelli, S.R. White, P.G. Black, G.J. Goni, and R.E. Cheney. Hurricane heat potential variability from in-situ and radar altimetry measurements. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 575-576 (2002).

No abstract.

Soloviev, A., J. Edson, W.R. McGillis, P. Schluessel, and R.H. Wanninkhof. Fine thermohaline structure and gas exchange in the near-surface layer of the ocean during GasEx-98. In Gas Transfer at Water Surfaces, M.A. Donelan, W.M. Drennan, E.S. Saltzman, and R.H. Wanninkhof (eds.). AGU Geophysical Monograph Series, Volume 127 (ISBN 0875909868), 181-185 (2002).

During the GasEx-98 field campaign, observations of the upper ocean structure were performed to identify relationships between the fine thermohaline structure, turbulence, and gas exchange in the near-surface layer of the ocean. The upper ocean dynamics were then simulated using a one-dimensional mixed layer model with the mixing parameterization developed during the TOGA Coupled Ocean-Atmosphere Response Experiment (COARE). The model was initialized with the temperature, salinity, and velocity profiles in the upper 50 m thick layer of the ocean obtained from the conductivity-temperature-depth (CTD) and acoustic Doppler current profiler (ADCP) measurements and was forced with the air-sea heat and momentum fluxes measured by Edson et al. (1999). The model produced a set of parameters, including the time and depth dependent mixing coefficient and the depth of the mixed layer. The simulated mixed layer depth is consistent with the depth of the actively mixed layer determined from the turbulence profiles taken occasionally during GasEx-98 Leg 2 with a free-rising profiler. Moderate wind speed conditions prevailed during GasEx-98 Leg 2 with several storms and a few periods of calm weather. Both the modeling and experimental results demonstrate that under conditions of low wind speed, the surface-generated turbulence is constrained within a relatively thin surface layer of the ocean. In the near-surface layer, appreciable temperature, salinity, and gas concentration differences are formed because of diurnal warming or precipitation effects. These results are applied to the estimation of the effect of mixed layer processes on the bulk-flux formulation for the air-sea exchange of gases.

Stamates, S.J. Predicting total suspended material concentration in the Chesapeake Bay estuary using a calibrated acoustic Doppler current profiler. M.S. thesis, University of Miami/Rosenstiel School of Marine and Atmospheric Studies, 54 pp. (2002).

Techniques recently published Deines (1999) indicate that the RD instruments broad-band acoustic Doppler current profiler received signal strength data can be calibrated in units of scattering volume (Sv). This calibration procedure is performed and described. Data collected from a field study conducted in Chesapeake Bay are used to develop several models relating total suspended materials as measured by calibrated optical devices to scattering volume as measured by a calibrated ADCP. The models are optimized using statistical methods and their performance is evaluated.

Suvorov, A.M., A.Kh. Khaliulin, E.A. Godin, and D.R. Palmer. An evaluation of the influence of interannual variability on climate analysis. Second International Conference on Oceanography of the Eastern Mediterranean and Black Sea, Ankara, Turkey, October 14-18, 2002. Middle East Technical University Publication, 444-445 (2002).

Most of the existing methods for calculating climate products from temperature and salinity data do not take into account interannual variability. As an illustration, most of the existing temperature and salinity data for the Black Sea were collected in the period from 1900 to 1995. In fact, more than 50% of these data were collected in the 1970s and 1980s. Without taking into account interannual variability, climate products calculated from these data can only reflect conditions during this brief period. For five areas of the Black Sea where existing data are plentiful, we have analyzed data for four levels below the cold intermediate layer where seasonal variability can be ignored. The analysis shows the existence of a pronounced interannual variability. Our results illustrate a dependence of the obtained results upon the method used for calculating the climate products.

Takahashi, T., S.C. Sutherland, C. Sweeney, A. Poisson, N. Metzl, B. Tillbrook, N. Bates, R.H. Wanninkhof, R.A. Feely, C.L. Sabine, J. Olafsson, and Y. Nojiri. Global sea-air CO₂ flux based on climatological surface ocean pCO₂ and seasonal biological and temperature effects. Deep-Sea Research, Part II, 49(9-10):1601-1622 (2002).

Based on about 940,000 measurements of surface-water pCO₂ obtained since the International Geophysical Year of 1956-1959, the climatological, monthly distribution of pCO₂ in the global surface waters representing mean non-El Ni�o conditions has been obtained with a spatial resolution of 4° × 5° for a reference year 1995. The monthly and annual net sea-air CO₂ flux has been computed using the NCEP/NCAR 41-year mean monthly wind speeds. An annual net uptake flux of CO₂ by the global oceans has been estimated to be 2.2 (+22% or 19%) Pg Cyr^-1 using the (wind speed)² dependence of the CO₂ gas transfer velocity of Wanninkhof (J. Geophys. Res. 97 (1992) 7373). The errors associated with the wind-speed variation have been estimated using one standard deviation (about ±2 m s^-1) from the mean monthly wind speed observed over each 4° × 5° pixel area of the global oceans. The new global uptake flux obtained with the Wanninkhof (wind speed)² dependence is compared with those obtained previously using a smaller number of measurements, about 250,000 and 550,000, respectively, and are found to be consistent within ±0.2 Pg Cyr^-1. This estimate for the global ocean uptake flux is consistent with the values of 2.0 ± 0.6 Pg Cyr^-1 estimated on the basis of the observed changes in the atmospheric CO₂ and oxygen concentrations during the 1990s (Nature 381 (1996) 218; Science 287 (2000) 2467). However, if the (wind speed)³ dependence of Wanninkhof and McGillis (Geophys. Res. Lett. 26 (1999) 1889) is used instead, the annual ocean uptake as well as the sensitivity to wind-speed variability is increased by about 70%. A zone between 40° and 60° latitudes in both the northern and southern hemispheres is found to be a major sink for atmospheric CO₂. In these areas, poleward-flowing warm waters meet and mix with the cold subpolar waters rich in nutrients. The pCO₂ in the surface water is decreased by the cooling effect on warm waters and by the biological drawdown of pCO₂ in subpolar waters. High wind speeds over these low pCO₂ waters increase the CO₂ uptake rate by the ocean waters. The pCO₂ in surface waters of the global oceans varies seasonally over a wide range of about 60% above and below the current atmospheric pCO₂ level of about 360 µatm. A global map showing the seasonal amplitude of surface-water pCO₂ is presented. The effect of biological utilization of CO₂ is differentiated from that of seasonal temperature changes using seasonal temperature data. The seasonal amplitude of surface-water pCO₂ in high-latitude waters located poleward of about 40° latitude and in the equatorial zone is dominated by the biology effect, whereas that in the temperate gyre regions is dominated by the temperature effect. These effects are about six months out of phase. Accordingly, along the boundaries between these two regimes, they tend to cancel each other, forming a zone of small pCO₂ amplitude. In the oligotrophic waters of the northern and southern temperate gyres, the biology effect is about 35 µatm on average. This is consistent with the biological export flux estimated by Laws et al. (Glob. Biogeochem.Cycles 14 (2000) 1231). Small areas such as the northwestern Arabian Sea and the eastern equatorial Pacific, where seasonal upwelling occurs, exhibit intense seasonal changes in pCO₂ due to the biological drawdown of CO₂.

Taylor, M.A., E.B. Enfield, and A.A. Chen. Influence of the tropical Atlantic versus the tropical Pacific on Caribbean rainfall. Journal of Geophysical Research, 107(C9):3127, doi:10.1029/2001JC001097 (2002).

The Caribbean rainfall season runs from May through November and is distinctly bimodal in nature. The bimodality allows for a convenient division into an early season (May-June-July) and a late season (August-September-October). Evidence suggests that interannual variability in the early season is influenced strongly by anomalies in the sea surface temperatures of the tropical North Atlantic, with positive anomalies over a narrow latitudinal band (0°-20 N) being associated with enhanced Caribbean rainfall. The coincidence of this band with the main development region for tropical waves suggests a modification of the development of the waves by the warmer tropical Atlantic. The strong influence of the tropical North Atlantic wanes in the late season, with the equatorial Pacific and equatorial Atlantic becoming more significant modulators of interannual variability. The spatial pattern of significant correlation suggests strongly the influence of the El Ni�o/La Ni�a phenomenon, with a warm Pacific associated with a depressed late season and vice versa. There additionally seems to be a robust relationship between late season Caribbean rainfall and an east-west gradient of sea surface temperature (SST) between the two equatorial oceanic basins. Oppositely signed SST anomalies in the NINO3 region and the central equatorial Atlantic (0°-15°W, 5°S-5°N) are well correlated with Caribbean rainfall for this period.

Thacker, W.C., and O.E. Esenkov. Assimilating XBT data into HYCOM. Journal of Atmospheric and Oceanic Technology, 19(5):709-724 (2002).

A scheme is presented for assimilating expendable bathythermographic data into HYCOM, an oceanic circulation model featuring a hybrid vertical coordinate. The scheme is fully multivariate, using observations of temperature to correct density, pressure, salinity, and momentum, in addition to temperature. Central to the scheme is the estimation of companion profiles of salinity and potential density. The potential density profiles are used to estimate the thicknesses of the model's layers, so that layer-averaged values of potential density and potential temperature can be computed. These derived data and the derived layer thicknesses are assimilated via optimal interpolation. Salinity corresponding to the corrected potential density and potential temperature fields is determined by the equation of state of seawater, and corrections to the momentum field are computed geostrophically from the corrections to the pressure field. The scheme is illustrated using data from March 1995 in the Atlantic Ocean.

Uhlhorn, E.W., and J.J. Cione. Real-time simulation of hurricane inner-core ocean cooling as a gauge for intensity change. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 658-659 (2002).

No abstract.

Walsh, E.J., C.W. Wright, D. Vandemark, L.F. Bliven, E.W. Uhlhorn, P.G. Black, and F.D. Marks. Rain rate measurements in Hurricane Humberto using the airborne NASA scanning radar altimeter. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 208-209 (2002).

No abstract.

Walsh, E.J., C.W. Wright, D. Vandemark, W.B. Krabill, A.W. Garcia, S.H. Houston, S.T. Murillo, M.D. Powell, P.G. Black, and F.D. Marks. Hurricane directional wave spectrum spatial variation at landfall. Journal of Physical Oceanography, 32(6):1667-1684 (2002).

The NASA Scanning Radar Altimeter (SRA) flew aboard one of the NOAA WP-3D hurricane research aircraft to document the sea surface directional wave spectrum in the region between Charleston, South Carolina, and Cape Hatteras, North Carolina, as Hurricane Bonnie was making landfall near Wilmington, North Carolina, on 26 August 1998. Two days earlier, the SRA had documented the hurricane wave field spatial variation in open water when Bonnie was 400 km east of Abaco Island, Bahamas. Bonnie was similar in size during the two flights. The maximum wind speed was lower during the landfall flight (39 m s^-1) than it had been during the first flight (46 m s^-1). Also, Bonnie was moving faster prior to landfall (9.5 m s^-1) than when it was encountered in the open ocean (5 m s^-1). The open ocean wave height spatial variation indicated that Hurricane Bonnie would have produced waves of 10 m height on the shore northeast of Wilmington had it not been for the continental shelf. The gradual shoaling distributed the wave energy dissipation process across the shelf so that the wavelength and wave height were reduced gradually as the shore was approached. The wave height 5 km from shore was about 4 m. Despite the dramatic differences in wave height caused by shoaling and the differences in the wind field and forward speed of the hurricane, there was a remarkable agreement in the wave propagation directions for the various wave components on the two days. This suggests that, in spite of its complexity, the directional wave field in the vicinity of a hurricane may be well behaved and lend itself to be modeled by a few parameters, such as the maximum wind speed, the radii of the maximum and gale force winds, and the recent movement of the storm.

Wang, C. Atlantic climate variability and its associated atmospheric circulation cells. Journal of Climate, 15(13):1516-1536 (2002).

Phenomena important for Atlantic climate variability include the Atlantic zonal equatorial mode, the tropical Atlantic meridional gradient mode, and the North Atlantic Oscillation (NAO). These climate phenomena and their associated atmospheric circulation cells are described and discussed using the NCEPVNCAR reanalysis field and the NCEP sea surface temperature (SST) from January 1950 to December 1999. Atmospheric divergent wind and vertical motion are used for the identification of atmospheric circulation cells. During the peak phase of the Atlantic equatorial mode, the Atlantic Walker circulation weakens and extends eastward, which results in surface westerly wind anomalies in the equatorial western Atlantic. These westerly wind anomalies are partly responsible for warming in the equatorial eastern Atlantic that occurs in the second half of the year. The Atlantic equatorial mode involves a positive ocean-atmosphere feedback associated with the Atlantic Walker circulation, similar to the Pacific El Ni�o. The tropical Atlantic meridional gradient mode is characterized by a strong SST gradient between the tropical North Atlantic (TNA) and the tropical South Atlantic. Corresponding to the meridional gradient mode is an atmospheric meridional circulation cell in which the air rises over the warm SST anomaly region, flows toward the cold SST anomaly region aloft, sinks in the cold SST anomaly region, then crosses the equator toward the warm SST region in the lower troposphere. The analysis presented here suggests that the Pacific El Ni�o can affect the TNA through the Walker and Hadley circulations, favoring the TNA warming in the subsequent spring of the Pacific El Ni�o year. The NAO, characterized by strong westerly airflow between the Icelandic low and the Azores high, is also related to an atmospheric meridional circulation. During the high NAO index, the atmospheric Ferrel and Hadley cells are strengthened, consistent with surface westerly and easterly wind anomalies in the North Atlantic and in the mid-to-tropical Atlantic, respectively.

Wang, C. Atmospheric circulation cells associated with the El Ni�o-Southern Oscillation. Journal of Climate, 15(4):399-419 (2002).

Atmospheric circulation cells associated with the El Ni�o-Southern Oscillation (ENSO) are described and examined using the NCEP-NCAR reanalysis field and the NCEP sea surface temperatures (SST) from January 1950 to December 1999. The divergent wind and pressure vertical velocity are employed for the identification of atmospheric circulation cells. The warm phase of ENSO shows positive SST anomalies in the equatorial eastern Pacific and along the east coast of Asia and the west coast of North America, and negative SST anomalies in the off-equatorial western Pacific and in the central North Pacific. Associated with this SST anomaly distribution are variations of atmospheric zonal and meridional circulation cells over the Pacific. The equatorial zonal Walker circulation cell is weakened, consistent with previous schematic diagrams. The anomalous meridional Hadley circulation cell in the eastern Pacific shows the air rising in the tropics, flowing poleward in the upper troposphere, sinking in the subtropics, and returning back to the tropics in the lower troposphere. The anomalous Hadley cell in the western Pacific is opposite to that in the eastern Pacific. The divergent wind and vertical velocity also show a midlatitude zonal cell (MZC) over the North Pacific. The mean MZC is characterized by the air rising in the central North Pacific, flowing westward and eastward in the upper troposphere, descending in the east coast of Asia and the west coast of North America, then returning back to the central North Pacific in the lower troposphere. The anomalous MZC during the mature phase of El Ni�o shows an opposite rotation to the mean MZC, indicating a weakening of the MZC.

Wang, C. ENSO and atmospheric circulation cells. CLIVAR Exchanges, 7:9-11 (2002).

No abstract.

Wanninkhof, R.H., S.C. Doney, T. Takahashi, and W.R. McGillis. The effect of using time-averaged winds on regional air-sea CO₂ fluxes. In Gas Transfer at Water Surfaces, M.A. Donelan, W.M. Drennan, E.S. Saltzman, and R.H. Wanninkhof (eds.). AGU Geophysical Monograph Series, Volume 127 (ISBN 0875909868), 351-356 (2002).

Gas transfer velocities are frequently related to wind speeds in order to estimate air-sea gas fluxes on regional and global scales. Since the gas exchange-wind speed relationships are non-linear, the wind speed distribution will have an effect on the fluxes if time-averaged winds are used. Commonly, a Weibull distribution is assumed for monthly or yearly averaged wind speeds. Although this is a reasonable assumption for global winds, significant regional deviations from this distribution exist. For areas with steady winds such as the trade wind regions and Westerlies in the Southern Ocean, the Weibull assumption will overestimate the long-term gas transfer velocities. Using regional wind speed distribution patterns based on 6-hour NCEP re-analysis winds instead of a Weibull distribution, the global oceanic CO₂ uptake estimate decreases by 5% if a quadratic dependence with wind speed is assumed and by 26% if a cubic dependence of gas exchange with wind speed is used.

Ward, B., and P.J. Minnett. An autonomous profiler for near surface temperature measurements. In Gas Transfer at Water Surfaces, M.A. Donelan, W.M. Drennan, E.S. Saltzman, and R.H. Wanninkhof (eds.). AGU Geophysical Monograph Series, Volume 127 (ISBN 0875909868), 167-172 (2002).

This paper describes the profiling instrument SkinDeEP (Skin Depth Experimental Profiler), which measures the temperature of the water column from a depth of about 6 m to the surface with high resolution thermometers. The instrument operates in an autonomous mode as it has the capability to change buoyancy by inflating a neoprene bladder attached to the body of the profiler. Measurements are recorded only during the ascending phase of the profile so as to minimize disturbances at the surface. Results from deployment of the profiler show strong temperature gradients within the bulk waters under conditions of high insolation. These data were compared to the skin temperatures as measured by the M-AERI (Marine-Atmospheric Emitted Radiance Interferometer), a high accuracy infrared spectroradiometer. The corresponding bulk-skin temperature differences, DELTA-T, were shown to have strong dependence on the depth of the bulk measurement during the daytime with low wind speeds, but at higher wind speeds, the depth dependence vanishes. One set of profiles under nighttime conditions is also presented, showing the presence of overturning and thus a heterogeneous temperature structure within the bulk.

Watlington, R.A., W.D. Wilson, W.E. Johns, and C. Nelson. Updated bathymetric survey of Kick-'em-Jenny submarine volcano. Marine Geophysical Researches, 23(3):271-276 (2002).

High-resolution bathymetric data obtained in July 1996 during a survey of the Kick-'em-Jenny submarine volcano north of Grenada in the Lesser Antilles revealed changes in the structure of the volcanic edifice compared to previously available surveys. The volcano's summit, at 178 m below sea level, was found to be approximately 18 m farther from the surface than was reported by Bouysse et al. (1988) and others. No dome was observed. Instead, an open crater, surrounded by walls that dropped significantly in elevation from one side to the opposite, suggest that eruptions, earthquakes, rockfalls, or explosions may have altered the structure since the last detailed survey. The deepest contour of the volcano's crater was found 106 m below the summit.

White, S.R., M.M. Mainelli, S.D. Jacob, and L.K. Shay. Hurricane heat potential estimates from monthly versus seasonal temperature and salinity data. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 128-129 (2002).

No abstract.

Willoughby, H.E. Aircraft observations of Hurricane Floyd. Proceedings, Second Workshop on Landfalling Typhoons in the Taiwan Area, Taipei, Taiwan, April 25-26, 2002. National Science Council, 35-51 (2002).

The 1995 through 2001 hurricane seasons produced 27 "major" hurricanes, in categories 3, 4, or 5 on the Saffir-Simpson scale. Only three of the major hurricanes that formed during the last six seasons reached U.S. shores with category 3 or greater intensity. This experience contrasts with a long-term expectation that about a third of Atlantic major hurricanes (i.e., 9 of the 27) would make U.S. landfall. Hurricane Floyd of 1999 is representative of the anticlimatic late 20th century major hurricanes. Like most of these storms, it formed from an African Wave. It intensified rapidly east of the Bahamas, reaching a minimum central pressure of 921 hPa on 13 September 1999. This pressure was nearly in equilibrium with the actual ocean surface temperature under the storm at that time. Subsequently, Floyd weakened through a concentric eyewall replacement, reintensified somewhat, and then weakened as a result of large-scale shear and less favorable thermodynamic conditions to category 2 before landfall in eastern North Carolina. Floyd's most serious impact was torrential rainfall that claimed 75 lives through drowning in the northeastern U.S., the largest mortality in a hurricane since Agnes in 1972. Intensive observations from instrumented aircraft, including flight-level data, radar, dropsondes, and air-expendable bathythermographs are the key to understanding of the factors that caused Floyd's rapid intensification and more gradual weakening.

Willoughby, H.E., and M.E. Rahn. A new parametric model of hurricane wind profiles. Preprints, 25th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, April 29-May 3, 2002. American Meteorological Society, Boston, 553-554 (2002).

No abstract.

Wilson, D.W., W.E. Johns, and S.L. Garzoli. Velocity structure of North Brazil Current rings. Geophysical Research Letters, 29(8):10.1029/2001GL013869 (2002).

High-resolution shipboard surveys of four North Brazil Current rings are presented, which are the first such dedicated surveys to be made of these features. Of the four rings surveyed, three fundamentally different types of ring structures are found: (1) a shallow, surface-trapped structure with velocities confined to the top 200 m (two rings); (2) a deep-reaching structure with significant swirl velocities (~0.2 m/s) extending to 2000 m (one ring); and (3) a thermocline-intensified structure with almost no detectable surface signature (one ring). The results of this study indicate that North Brazil Current rings can have highly variable vertical structures, and that assessing their overall role in cross gyre exchange in the tropical Atlantic will require a careful combination of remote sensing and in-situ observations.

Yvon-Lewis, S.A., and J.H. Butler. Effect of oceanic uptake on atmospheric lifetimes of selected trace gases. Journal of Geophysical Research, 107(D20):4414, doi:10.1029/2001JD001267 (2002).

We have calculated from a 2° x 2° grid of oceanic properties the contribution of oceanic loss to the overall lifetimes of a number of anthropogenic and naturally produced trace gases involved in global warming and stratospheric ozone depletion. The model, originally developed for atmospheric methyl bromide, can be used for any well-mixed trace gas where the seawater degradation rate constants and solubilities are known. Of the gases tested, it is clear that known oceanic chemical degradation processes alone are not significant sinks for most HFCs and HCFCs. Chemical degradation in the oceans is a substantial sink for COS (28%) and COCl₂ (8%) and a minor sink for CH₃Cl (<2%) and CH₃I (2.5%), and it should be considered when determining atmospheric lifetimes and sink strengths for these gases. Biological degradation processes are likely to increase the oceanic uptake rates of many gases.

Yvon-Lewis, S.A., J.H. Butler, E.S. Saltzman, P.A. Matrai, D.B. King, R. Tokarczyk, R.M. Moore, and J.-Z. Zhang. Methyl bromide cycling in a warm-core eddy of the North Atlantic. Global Biogeochemical Cycles, 16(4):1141, doi:10.1029/2002GB001898 (2002).

We conducted a detailed investigation of the evolution of methyl bromide concentrations, degradation rates, and ventilation rates for 26 days in a naturally contained, warm-core eddy of the North Atlantic Ocean. This is the first study of the oceanic cycling of methyl bromide in a natural, contained system with a complete suite of supporting measurements of physical and chemical variables. Methyl bromide concentrations in the mixed layer ranged from 2.3 to 4.2 nmol m^-3, degradation rates ranged from 0.1 to 0.9 nmol m^-3 d^-1, net sea-to-air exchange rates ranged from 0 to 0.5 nmol m^-3 d^-1, and net loss rates through the thermocline were less than 0.1 nmol m^-3 d^-1. From a mass balance for methyl bromide in the mixed layer, we calculated production rates ranging from <0.1 to 1.3 nmol m^-3 d^-1. The median of this range, 0.48 nmol m^-3 d^-1, is higher than the ~0.15 nmol m^-3 d^-1 necessary to maintain the reported global oceanic emission of 56 Gg yr^-1. This is reasonable, because our study area was supersaturated in methyl bromide, whereas the ocean as a whole is undersaturated.

Zhang, J.-Z., and J. Chi. Automated analysis of nanomolar concentrations of phosphate in natural waters with liquid waveguide. Environmental Science and Technology, 36(5):1048-1053 (2002).

Concentrations of phosphate in natural waters are often below the detection limits of conventional nutrient auto-analyzers by either gas-segmented continuous flow analysis or flow injection analysis. A liquid waveguide capillary flow cell has been used to extend the sensitivity of a conventional auto-analyzer for automated analysis of nanomolar concentrations of phosphate in natural waters. Total reflection of light can be achieved within the liquid core of the flow cell, as the refractive index of cell wall coated with Teflon 1600 is lower than water. This property allows the manufacturers to construct long liquid waveguide capillary flow cells in a helical, rather than linear shape, with compact dimensions. A small sample volume is required because the internal volume of a 2-m long capillary flow cell is only approximately 0.5 cm³. Adaptation of this long flow cell to auto-analyzers significantly enhances the sensitivity of automated colorimetric analysis of phosphate with molybdenum blue method, allowing for accurate and precise determination of nanomolar concentrations of phosphate in natural waters. The advantages of this technique are a low detection limit (0.5 nM), small sample volume (2 mL), high precision (2% at 10 nM levels), and automation for rapid analysis of a large number of samples.

Zhang, J.-Z., and F.J. Millero. Comment on "A kinetic study of the oxidation of S(IV) in seawater." Environmental Science and Technology, 36(4):817 (2002).

No abstract.

Zhang, J.-Z., G.A. Berberian, and R. Wanninkhof. Long-term storage of natural water samples for dissolved oxygen determination. Water Research, 36(16):4165-4168 (2002).

A method for preserving natural water samples for dissolved oxygen analysis is recommended. The conventional method of using greased glass stoppers has been found to cause a 12% increase in oxygen concentration over a one-month period as a result of evaporation of water sample through micro-gaps and concurrent intrusion of air into the water sample bottles. Sealing the sample bottles with water has been found to be the optimal storage method. It permits a 100.2 ± 0.3% recovery of dissolved oxygen concentration from storage seawater samples over four months. **2001**

Aberson, S.D. The ensemble of tropical cyclone track forecasting models in the North Atlantic Basin (1976-2000). Bulletin of the American Meteorological Society, 82(9):1895-1904 (2001).

The suite of tropical cyclone track forecast models in the Atlantic basin from the 1976 to 2000 hurricane seasons are treated as a forecast ensemble. The 12-h ensemble mean forecast, adjusted for forecast difficulty, has improved at a rate of just under 1% per year, and the improvement rate increases to almost 2.4% per year for the 72-h forecasts. The average size of the 72-h (48-h) error in 1976 is less than the average size of the 48-h (36-h) error in 2000. The average 36-h forecast error in 2000 is comparable to the 24-h forecast error in 1976. The ensemble currently spans the true path of the tropical cyclone in the cross-track direction more than 90% of the time and in the alongtrack direction between 60% and 90% of the time depending on the forecast lead time. The ensemble spread is unable to provide estimates of individual forecast reliability, likely making probabilistic landfall forecasts from this ensemble unreliable. The reliability of the spread in the cross-track direction suggests the possibility of limiting hurricane watch and warning regions depending upon the ensemble spread at landfall.

Aberson, S.D., S.J. Majumdar, and C.H. Bishop. A real-time ensemble for the prediction of hurricane tracks in the Atlantic basin. Preprints, 18th Conference on Weather Analysis and Forecasting and 14th Conference on Numerical Weather Prediction, Fort Lauderdale, FL, July 30-August 2, 2001. American Meteorological Society, Boston, 456-457 (2001).

No abstract.

Alvarez-Zarikian, C.A., P.L. Blackwelder, T. Hood, H.R. Wanless, T.A. Nelsen, and C. Featherstone. Impact on the sedimentary record derived from micropaleontological data. Proceedings, 2001 Florida Bay and Adjacent Marine Systems Science Conference, Key Largo, FL, April 23-26, 2001. University of Florida, 58-59 (2001).

Hurricanes are the strongest force causing immediate and long-term environmental changes to coastal areas in the lower Everglades and Florida Bay, and their sedimentary record. Hurricane-induced sediment erosion and deposition, and bi-directional sediment transport, can disrupt the sediment record, blending the signature of other ecological factors (i.e., salinity fluctuations) and leaving behind a complex overprint of natural and anthropogenic influences. Their frequency is also a potential mechanism for carbon storage and removal. Paleohurricane impact in the stratigraphic record is marked by abrupt changes in microfaunal abundance and community structure, as well as in quantitative and qualitative organic carbon content and sediment texture. Hurricane signatures, verifiable by offsets in ²¹⁰Pb-geochronology data, are found in sediment cores recovered from Florida and Oyster Bays. Sediment core location controls the magnitude of variations in the sediment record. Semi-protected areas such as Oyster Bay exhibit the least amount of sediment disruption during and following the Labor Day Hurricane of 1935 and Hurricane Donna in 1960, whereas unprotected or less protected areas such as the First National Bank and Jimmy Key in western and central Florida Bay, respectively, experience the greatest effects.

Alvarez-Zarikian, C.A., P.K. Swart, T. Hood, P.L. Blackwelder, T.A. Nelsen, and C. Featherstone. A century of environmental variability in Oyster Bay using ostracode ecological and isotopic data as paleoenvironmental tools. Bulletin of American Paleontology, 361:133-143 (2001).

Stable isotopic analysis (delta¹⁸O and delta¹³C) and characterization of the ostracode community structure were carried out from a high-resolution sediment core recovered from Oyster Bay in the west of the Everglades National Park. Because of its location between Shark River Slough (SRS) and the Gulf of Mexico, the Oyster Bay core locality experiences extreme salinity fluctuations due to the interaction of freshwater run-off, precipitation, and marine water inputs. Ostracode population dynamics and isotopic variability over the 20th century are linked to natural and anthropogenic forces that affect the south Florida coastal ecosystem on interannual to decadal time scales. Three ostracode assemblages can be recognized within the 100 year sediment-core record: the first extending from the turn of the century to about 1950; the second, from the early 1950s to the late 1970s; and the third to core recovery in 1995. An abrupt decrease in ostracode abundance, species diversity, and shifts in species dominance occurred in the mid-1980s and reflects episodes of environmental stress. Markedly enriched delta¹⁸O values from the ostracode Peratocytheridea setipunctata and the benthic foraminifer Ammonia parkinsoniana typica at this time are concurrent with a major regional drought in south Florida, as well as with documented algal blooms and major die-off of sea grasses in Florida Bay. In addition, the timing of these events is contemporaneous to the onset of the South Florida Water Management District "Rainfall Plan" and the closing of the Buttonwood Canal. Higher ostracode abundance and species richness occurs between the late 1950s and late 1970s. Stable isotopic data and ostracode assemblage characteristics suggest a period of relative environmental stability and possibly improved water circulation in Whitewater Bay and Oyster Bay. Fluctuations in community structure during this time are most systematic and appear to be temporally correlated to rainfall variability patterns. Water management policies at this time are also discernable from the microfaunal and isotopic record, particularly the Congressionally mandated Monthly Minimum Allocation Plan of water supply to SRS. Before 1950, hurricane events and their effects are the major cause for immediate modifications within the ostracode community, although our data show that ostracode populations are capable of rapid recovery. Over the complete record of the last century, the effects of water management practices can be assessed from information embedded in the ostracode record. Nevertheless, the effects of natural climatic variability in Oyster Bay appear to outweigh the impact of anthropogenic forces.

Baringer, M.O., and J.C. Larsen. Sixteen years of Florida Current transport at 27°N. Geophysical Research Letters, 28(16):3179-3182 (2001).

Daily transports of the Florida Current have been inferred since 1982 through the use of submerged submarine telephone cables that measure the voltage difference across the Straits of Florida. Using all 16 years of data, the annual cycle ranges from a minimum of 30 Sv in January to a maximum of 33.5 Sv in July. The annual cycle is not stable throughout the entire period, however; the first eight years show a slightly larger peak-to-peak annual range of 5 Sv, while the second eight years have a semi-annual cycle with a distinct minimum in July and peak-to-peak range of 4 Sv. Filtered Florida Current transports contain a two to three year variation between 2 and 3 Sv in amplitude and a decadal variation of about �2 Sv. The decadal changes in the Florida Current transport are significantly correlated (R = 0.75 at 95% significance) to the North Atlantic Oscillation Index.

Bentamy, A., K.B. Katsaros, A.M. Mestas-Nunez, E.B. Forde, W.M. Drennan, and H. Roquet. Latent heat fluxes over the ocean from merged satellite data. Proceedings, Intercomparison and Validation of Ocean-Atmosphere Flux Fields Workshop, Potomac, MD, May 21-24, 2001. WCRP-115-WMO/TD-No. 1083, 205-208 (2001).

The specific objectives of this paper emphasize estimation of global latent heat flux over the oceans with high spatial and temporal resolution using satellite radar and radiometer measurements. Consistency of the same surface parameters retrieved from several satellites is assured. The flux fields are compared to in-situ observations and atmospheric analysis fields globally and in different regions of the ocean with particular focus on the tropical oceans.

Brenner, R.J., M.J. Dagg, and P.B. Ortner. Growth, grazing, distribution, and carbon demand in the plankton of Florida Bay. Proceedings, 2001 Florida Bay and Adjacent Marine Systems Science Conference, Key Largo, FL, April 23-26, 2001. University of Florida, 103-104 (2001).

The zooplankton community of Florida Bay was examined over four years from September 1994 through November 1998 to determine zooplankton distribution and abundance and to allow calculation of community metabolic demands. Net zooplankton were collected at 10 sites within the Bay on a bimonthly basis using a 64 µm net, and copepod nauplii were collected from the surface at each site using a 10L bucket and 20 µm mesh. The net zooplankton were split into four functional groups: copepods, copepods nauplii, meroplanktonic larvae, and "others." The microplankton community was also investigated using the dilution technique of Landry and Hassett (1982). Microphytoplankton growth and microzooplankton grazing rates were determined fluorometrically at four sites, one in each region, from May 1997 through September 1998. Community structure within the microphytoplankton was determined using HPLC analysis. All data were used to determine if the four regions of Phlips et al. (1995), which were established based on primarily physical characteristics of the waters within each region, were applicable to the zooplankton community of Florida Bay. The copepod community was typically dominated by three genera--Acartia, Oithona, and Paracalanus--though other genera occasionally constituted >20% of the copepod stock. The "others" category was typically composed of chaetognaths, larvaceans, medusae, isopods, flatworms, and polychaetes, with distributions and abundances varying with no obvious seasonality. Copepods and their nauplii dominated the net zooplankton numerically and in terms of biomass and metabolic demands. Seasonal trends were apparent for most parameters within each group, with maxima occurring most frequently during the summer or fall and minima in the winter.

Broecker, W.S., C. Langdon, T. Takahasi, and T.-H. Peng. Factors controlling the rate of CaCO₃ precipitation on Great Bahama Bank. Global Biogeochemical Cycles, 15(3):589-596 (2001).

Measurements by Langdon et al. (2000) in the man-made mesocosm coral reef at Biosphere 2's ocean reveal a strong dependence of calcification rate on the degree of supersaturation of CaCO₃ in seawater. A similar trend was previously encountered on the Bahama Banks, where Halimeda and other calcifiers are likely responsible for aragonite precipitation (Broecker and Takahashi, 1966). In this paper, we compare these two sets of results and conclude that the dependence on saturation state is significant but less strong in the Bahamas. However, it must be kept in mind that to some extent, the reduction of CaCO₃ precipitation on the Bahama Banks may be due to impact of higher salinity on the growth of the calcifying algae. However, if, as many sedimentologists are convinced, the precipitation of CaCO₃ on the Bahama Banks is inorganic (Macintyre and Reid, 1992; Milliman et al., 1993), then the comparison of the Bahamas and Biosphere 2 results for dependence of calcification rate on saturation state is telling us something quite different.

Campos, E., A. Busalacchi, S.L. Garzoli, J. Lutjeharms, R. Matano, P. Nobre, D. Olson, A. Piola, C. Tanajura, and I. Wainer. Important aspects of the South Atlantic to the understanding of the global climate. In Observing the Oceans in the 21st Century: A Strategy for Global Ocean Observations, C.J. Koblinsky and N.R. Smith (eds.). GODAE Project Office, 20 pp. (2001).

Important aspects of the South Atlantic physical oceanography are discussed, and an attempt is made to identify key processes and areas which need to be monitored in order to understand the role of that part of the ocean in the global climate variability. Given the importance of the South Atlantic, it becomes crucial that variables such as sea surface temperature, currents, and surface fluxes be monitored on a continuous basis if one wishes to determine and predict the relationship between oceanic variability in the South Atlantic and global or regional climate. Thus, we understand that efforts should be concentrated in the study of the air-sea-land interactions leading to sea surface temperature variability, and the processes associated with the inter-hemispheric exchange of mass and heat by the Atlantic Meridional Overturning Cell. The knowledge of long-term variations of the Atlantic thermohaline circulation and how these variations lead to changes in SST and oceanic heat transports are key issues to be addressed. With regard to the thermohaline circulation, we identify some key locations where very important processes occur, and need to be monitored. These are the Brazil-Malvinas Confluence, the Agulhas Retroflection, the Benguela Current, and the bifurcation of the South Equatorial Current (SEC). Based on the topics discussed in this article, a sustainable observational program in the South Atlantic is proposed, based on a combination of ship-based hydrographic samplings, moored arrays of current meters and other profiling instruments, satellite-tracked drifters and ARGO floats, repeat cruises and SOOP XBT lines, acoustic measurements, surface flux measurements, and remote sensing. Contribution of the South American oceanographic community would be of great interest in the monitoring of the Brazil-Malvinas Confluence and South Equatorial Current Bifurcation regions. Cooperation with the African community would be desirable for the surveys in the Agulhas Retroflection and the Benguela Current.

Daly, K.L., W.O. Smith, G.C. Johnson, G.R. DiTullio, D.R. Jones, C.W. Mordy, R.A. Feely, D.A. Hansell, and J.-Z. Zhang. Hydrography, nutrients, and carbon pools in the Pacific sector of the Southern Ocean: Implications for carbon flux. Journal of Geophysical Research, 106(C4):7107-7124 (2001).

We investigated the hydrography, nutrients, and dissolved and particulate carbon pools in the western Pacific sector of the Antarctic Circumpolar Current (ACC) during austral summer 1996 to assess the region's role in the carbon cycle. Low fCO₂ values along two transects indicated that much of the study area was a sink for atmospheric CO₂. The fCO₂ values were lowest near the Polar Front (PF) and the Subtropical Front (STF), concomitant with maxima of chlorophyll a and particulate and dissolved organic carbon. The largest biomass accumulations did not occur at fronts, which had high surface geostrophic velocities (20-51 cm s^-1), but in relatively low velocity regions near fronts or in an eddy. Thus, vertical motion and horizontal advection associated with fronts may have replenished nutrients in surface waters but also dispersed phytoplankton. Although surface waters north of the PF have been characterized as a "high nutrient-low chlorophyll" region, low silicic acid (Si) concentrations (2-4 µM) may limit production of large diatoms and, therefore, the potential carbon flux. Low concentrations (4-10 µM Si) at depths of winter mixing constrain the level of Si replenishment to surface waters. It has been suggested that an increase in aeolian iron north of the PF may increase primary productivity and carbon export. Our results, however, indicate that while diatom growth and carbon export may be enhanced, the extent ultimately would be limited by the vertical supply of Si. South of the PF, the primary mechanism by which carbon is exported to deep water appears to be through diatom flux. We suggest that north of the PF, particulate and dissolved carbon may be exported primarily to intermediate depths through subduction and diapycnal mixing associated with Subantarctic Mode Water and Antarctic Intermediate Water formation. These physical-biological interactions and Si dynamics should be included in future biogeochemical models to provide a more accurate prediction of carbon flux.

Dunion, J.P., C.S. Velden, and J.R. Rhome. Satellite applications for tropical wave/tropical cyclone tracking. Preprints, 18th Conference on Weather Analysis and Forecasting, Ft. Lauderdale, FL, July 30-August 2, 2001. American Meteorological Society, Boston, 436-438 (2001).

No abstract.

Enfield, D.B. Changes in sea surface temperatures influence rain patterns. Environmental Review, 8(11):1-8 (2001).

No abstract.

Enfield, D.B. Evolution and historical perspective of the 1997-1998 El Ni�o-Southern Oscillation event. Bulletin of Marine Science, 69(1):7-25 (2001).

The ocean thermal history of the 1997-98 El Ni�o episode is described in detail, with emphasis on developments along the equator and eastern Pacific coastlines. The temporal evolution of the warming and its causes are traced from the western Pacific, past the Galapagos Islands, and on to the subpolar gyres off North and South America. Along the equator, the event was characterized by a subsurface warm anomaly that slowly made its way from west to east across the Pacific from mid-1996 until early 1997, whence it triggered the onset of surface anomalies at the eastern terminus of the equatorial waveguide. The thermocline depression off Ecuador intensified from mid-1997 through the end of the year, culminating in a mature phase with maximum sea surface temperature anomalies (SSTA) around November-December 1997. The event gradually abated thereafter until the beginning of the subsequent cool phase (La Ni�a) was detected in July 1998. Following their arrivals at the eastern boundary, equatorial Kelvin waves proceeded poleward into both hemispheres as coastal trapped waves, carrying the thermocline depression signal with them along with associated nutrient deficiencies and ecosystem impacts. The poleward propagation of SSTA was more uniform and faster south of the equator, reaching south-central Chile with amplitudes of 2°C or greater. North of the equator the propagation was discontinuous, with decreased anomalies south of 20°N and a revival of SSTA in excess of 2°C, north of there, but with considerably larger time lags than observed off Chile. The possible reasons for these interhemispheric differences are discussed. The magnitude of the event is also discussed in an historical context, with emphasis on comparisons to the El Ni�o of 1982-83. Each of the two events, in its own way, set records. However, the two events are generally comparable in their magnitudes and the extent of their impacts, while both are top-ranked events for the period after 1950. In the centennial context, however, these events are not unprecedented, considering that they were probably enhanced by strong decadal warming during the 1980s and 1990s. An attempt is made to assess the accuracy of model forecasts of the 1997-1998 event. Two recent studies are discussed which generally agree that statistical and dynamical models under-predicted the equatorial warming prior to its onset and failed to capture the strong, early onset at all. Predictions of the late-1997 climax, with shorter lead times, improved once the data showing large mid-1997 anomalies were ingested into the models. However, the revised predictions were not in time to guide the successful atmospheric climate outlook for North America, which was issued in June 1997 on the basis of observed strong anomalies on the equator.

Enfield, D.B., A.M. Mestas-Nunez, and P.J. Trimble. The Atlantic multidecadal oscillation and its relation to rainfall and river flows in the continental U.S. Geophysical Research Letters, 28(10):2077-2080 (2001).

North Atlantic sea surface temperatures for 1856-1999 contain a 65-80 year cycle with a 0.4°C range, referred to as the Atlantic Multidecadal Oscillation (AMO) by Kerr (2000). AMO warm phases occurred during 1860-180 and 1940-1960, and cool phases during 1905-1925 and 1970-1990. The signal is global in scope, with a positively correlated co-oscillation in parts of the North Pacific, but it is most intense in the North Atlantic and covers the entire basin there. During AMO warmings, most of the United States sees less than normal rainfall, including Midwest droughts in the 1930s and 1950s. Between AMO warm and cool phases, Mississippi River outflow varies by 10% while the inflow to Lake Okeechobee, Florida varies by 40%. The geographical pattern of variability is influenced mainly by changes in summer rainfall. The winter patterns of interannual rainfall variability associated with El Ni�o-Southern Oscillation are also significantly changed between AMO phases.

Feely, R.A., C.L. Sabine, T. Takahashi, and R. Wanninkhof. Uptake and storage of carbon dioxide in the ocean: The global CO₂ survey. Oceanography, 14(4):18-32 (2001).

No abstract.

Fine, R.A., K.A. Maillet, K.F. Sullivan, and D. Willey. Circulation and ventilation flux of the Pacific Ocean. Journal of Geophysical Research, 106(C10):22,159-22,178 (2001).

The flux of water from the mixed layer into the thermocline/intermediate layers of the Pacific Ocean is quantified using chlorofluorocarbon (CFC) and hydrographic data. The total ventilation flux of at least 123 Sv for the South Pacific (SP) only slightly exceeds that of at least 111 Sv for the North Pacific (NP). Although the overall ventilation flux (to 27.3 sigma_theta) is similar in the NP and SP, the partitioning amongst the water masses is markedly different. In the NP, the partitioning is equal between the wind-driven (< 26.5 sigma_theta) and thermohaline (>26.5-27.3 sigma_theta) layers. While in the SP, the ventilation flux of the thermohaline layers exceeds by nearly 2:1 the wind-driven layers. The wind-driven subtropical gyre thermocline ventilation flux for the NP (41 Sv) exceeds the SP (25 Sv), and both agree well with literature estimates of Sverdrup transports. The ventilated volumes and ages are related to the wind stress curl and surface buoyancy fluxes. In the thermocline, ventilation of Shallow Salinity Minimum Water (22 m yr^-1 in the NP, 15 m yr^-1 in the SP) and Subtropical Mode Water is more effective in the NP than in the SP. In contrast, in the thermohaline layers direct air-sea exchange during convective formation of Subantarctic Mode and Antarctic Intermediate Water is more effective in ventilating the SP than processes in the NP. These same differences are also used to explain the larger volume of the shadow zone in the NP. In the subpolar regions, the ventilation fluxes can be used to infer formation rates of 8 Sv for the NP Intermediate Water and 9 Sv for the Subantarctic Mode Water. Into the tropical Pacific there is a substantial flux of 35 Sv of extratropical water for the wind-driven layers and 36 Sv for the thermohaline layers. The relatively young CFC-derived ages (5-20 years increasing with increasing density) show that a climate anomaly introduced into the subtropical thermocline could be transported into the tropics relatively quickly.

Fine, R.A., L. Merlivat, W. Roether, P. Schlosser, W.M. Smethie, Jr., and R. Wanninkhof. Observing tracers and the carbon cycle. In Observing the Oceans in the 21st Century: A Strategy for Global Ocean Observations, C.J. Koblinsky and N.R. Smith (eds.). GODAE Project Office and Bureau of Meteorology, Melbourne, Australia, 361-375 (2001).

No abstract.

Garzoli, S.L. CLIVAR workshop on tropical Atlantic variability. CLIVAR Exchanges, 6(4):33-35 (2001).

No abstract.

Garzoli, S.L., and R.L. Molinari. Ageostrophic transport in the upper layers of the tropical Atlantic Ocean. Geophysical Research Letters, 28(24):4619-4622 (2001).

A test of the theoretical Ekman relation in the tropical Atlantic Ocean is performed by comparing estimated Ekman transport with observations collected along two transects symmetric about the equator (6°N and 6°S). Ekman transport is calculated theoretically using ship winds and climatological data. Total ageostrophic transport is obtained by subtracting the observed geostrophic transports from the measured total transports using the data collected along the two transects. Along 6°S, both the zonal mean ageostrophic transport and its variability with longitude can be accounted for by the theoretical Ekman transport. Along 6°N, the total ageostrophic and Ekman transports agree, but significant differences are found in the cumulative transport curves between the African coast and about 40°W. These departures from theory may be related to the effect of advective terms in the Ekman relation and/or other ageostrophic motion at the reference depth for the comparisons.

Goldenberg, S.B., C.W. Landsea, A.M. Mestas-Nunez, and W.M. Gray. The recent increase in Atlantic hurricane activity: Causes and implications. Science, 293(5529):474-479 (2001).

The years 1995 to 2000 experienced the highest level of North Atlantic hurricane activity in the reliable record. Compared with the generally low activity of the previous 24 years (1971 to 1994), the last six years have seen a doubling of overall activity for the whole basin, a 2.5-fold increase in major hurricanes (>50 m/s), and a fivefold increase in hurricanes affecting the Caribbean. The greater activity is caused by simultaneous increases in North Atlantic sea-surface temperatures and decreases in vertical wind shear, both of which are known to favor hurricane formation. Because these changes exhibit a multidecadal time scale, the present high level of hurricane activity is likely to persist for an additional 10 to 40 years. The shift in climate calls for a reevaluation of preparedness and mitigation strategies.

Goni, G.J., and W.E. Johns. A census of North Brazil Current rings observed from TOPEX/POSEIDON altimetry: 1992-1998. Geophysical Research Letters, 28(1):1-4 (2001).

Six years of TOPEX/POSEIDON altimeter data are used to investigate the formation of rings and eddies shed by the North Brazil Current. Upper layer thickness maps were used to identify 34 of these features formed in the North Brazil Current retroflection region, an average of more than five rings and eddies per year. The ensemble of ring trajectories closely parallels the 500 m isobath, and one out of six rings penetrate into the Caribbean Sea through the southern Lesser Antilles. The rest of the rings and eddies follow a northern trajectory past Barbados once they reach 58°W. Their estimated mean translation speed is 14 km/day and their mean length scale is approximately 100 km. Our results suggest that the formation rate of NBC rings and eddies is nearly twice that previously thought, and that they may account for more than one-third of the interhemispheric transport within the Atlantic meridional overturning cell.

Goni, G.J., and I. Wainer. Brazil Current front dynamics from altimeter data. Journal of Geophysical Research, 106(C12):31,117-31,128 (2001).

The southwestern Atlantic is characterized by the confluence of the Brazil and Malvinas Currents forming very strong surface and subsurface fronts which can be detected from hydrographic and remote sensing procedures. Three data sets, consisting of TOPEX/Poseidon-derived sea height anomalies and the climatologically-derived depth of the 10°C isotherm and reduced gravity, are used within a two-layer dynamical ocean model context to monitor the Brazil Current front and to investigate its variability during a six-year period (1993 through 1998). Results reveal that the fronts exhibit motions that are larger zonally than meridionally, showing strong interannual variability with annual mean amplitudes that range from 1 to 6 degrees. The annual and semiannual components account for more than 75% of the variability of the frontal oscillations. In the annual cycle, the frontal motions appear to be closely related to fluctuations in the baroclinic transport of the Brazil Current and are only influenced by the Malvinas Current when the Brazil Current transport is very small.

Goodwin, K.D., R.K. Varner, P.M. Crill, and R.S. Oremland. Consumption of tropospheric levels of methyl bromide by C1 bacteria and comparison to saturation kinetics. Applied and Environmental Microbiology, 67(12):5437-5443 (2001).

Pure cultures of methylotrophs and methanotrophs are known to oxidize methyl bromide (MeBr); however, their ability to oxidize tropospheric concentrations (parts per trillion by volume [pptv]) has not been tested. Methylotrophs and methanotrophs were able to consume MeBr provided at levels that mimicked the tropospheric mixing ratio of MeBr (12 pptv) at equilibrium with surface waters (~2 pM). Kinetic investigations using picomolar concentrations of MeBr in a continuously stirred tank reactor (CSTR) were performed using strain IMB-1 and Leisingeria methylohalidivorans strain MB2^T, terrestrial and marine methylotrophs capable of halorespiration. First-order uptake of MeBr with no indication of threshold was observed for both strains. Strain MB2^T displayed saturation kinetics in batch experiments using micromolar MeBr concentrations, with an apparent K_s of 2.4 µM MeBr and a V_max of 1.6 nmol h^-1 (10⁶ cells)^-1. Apparent first-order degradation rate constants measured with the CSTR were consistent with kinetic parameters determined in batch experiments, which used 35- to 1 x 10⁷-fold higher MeBr concentrations. Ruegeria algicola (a phylogenetic relative of strain MB2^T), the common heterotrophs Escherichia coli and Bacillus pumilus, and a toluene-oxidizer, Pseudomonas mendocina KR1, were also tested. These bacteria showed no significant consumption of 12 pptv MeBr; thus, the ability to consume ambient mixing ratios of MeBr was limited to C₁-oxidizing bacteria in this study. Aerobic C₁ bacteria may provide model organisms for the biological oxidation of tropospheric MeBr in soils and waters.

Hare, J.A., D.E. Hoss, A.B. Powell, M. Konieczna, D.S. Peters, S.R. Cummings, and R. Robbins. Larval distribution and abundance of the family Scombridae and Scombrolabracidae in the vicinity of Puerto Rico and the Virgin Islands. Bulletin of the Sea Fisheries Institute, 2(153):13-29 (2001).

Fishes of the family Scombridae are important recreational and commercial species throughout the western Central Atlantic Ocean. There remain, however, many questions regarding the biology of these fishes that are crucial for the protection of sustainable fisheries. To provide some basic information, this study examines larval distribution and abundance in the vicinity of Puerto Rico and the Virgin Islands, an area of sparse information compared to the Gulf of Mexico and the southeastern United States coast. Seasonal, horizontal, and vertical distributions were examined and species-specifics patterns were described. Thunnus atlanticus and Katsuwonus pelamis were abundant during a November/December cruise, while Thunnus atlanticus, Katsuwonus pelamis and Euthynnus alletteratus were abundant during a May cruise. Regional differences were found in the distribution of some species and species specific vertical distributions were identified. Thunnus atlanticus was more surface oriented than Euthynnus alletteratus and Katsuwonus pelamis. These results are discussed relative to prior work in the region.

Hendee, J.C., E. Mueller, C. Humphrey, and T. Moore. A data-driven expert system for producing coral bleaching alerts at Sombrero Reef in the Florida Keys. Bulletin of Marine Science, 69(2):673-684 (2001).

A computer expert system shell was employed to provide interpretations of near real-time acquired combinations of meteorological and oceanographic parameters from a SEAKEYS (Sustained Ecological Research Related to Management of the Florida Keys Seascape) station at Sombrero Reef. When environmental conditions were conducive to coral bleaching, according to different models, alerts were automatically posted to the World-Wide Web and emailed to researchers so they could verify and study bleaching events as they might happen. The models were refined using feedback from field data on bleaching recorded after alerts from the expert system. The expert system was programmed to produce alerts when sea temperatures over 30°C occurred, or when temperatures of 30°C occurred concomitant with low winds. Alerts were produced in June 1998 when these conditions were met, but bleaching did not occur. Reconfiguration of the system, which included a point system for three models (high sea temperature only, high sea temperature plus low winds, high sea temperature plus low winds plus low tide), resulted in the transmittal of alerts which coincided with bleaching during early August 1998. Bleaching occurred after sea temperature reached an average of 31.5°C over a period of three days, with excursions over 31.8°C occurring over 15 times during those three days. High sea temperatures, low wind speeds, and a very low tide occurred coincident to the time of bleaching, but it was not possible to tell if these were factors acting synergistically.

Hood, E.M., R.H. Wanninkhof, and L. Merlivat. Short time scale variations of fCO₂ in a North Atlantic warm-core eddy: Results from the GASEX-98 carbon interface ocean atmosphere (CARIOCA) buoy data. Journal of Geophysical Research, 106(C2):2561-2572 (2001).

During a Lagrangian deliberate tracer study in the North Atlantic, the 1998 Gas Exchange Experiment (GASEX-98), hourly measurements of wind speed, sea surface temperature, fCO₂, and fluorescence were made from two carbon interface ocean atmosphere (CARIOCA) drifting buoys in a warm-core eddy near 46°N and 21.5°W over a period of approximately 20 days. Shipboard measurements of fCO₂ near the buoys were used to verify the buoy operation, calibrate the buoy measurements, and assess the performance of the fCO₂ sensor. The strong air-sea fCO₂ gradient in the eddy and intense atmospheric forcing during the experiment provided ideal conditions for demonstrating the potential of autonomous drift buoy measurements for studies of surface ocean biogeochemistry, where changes of fCO₂ were rapid and large. During the experiment, a storm occurred with wind speeds reaching as high as 16-17 m s^-1, leading to a sharp decrease in sea surface temperature and an increase in fCO₂ of ~30 µatm. The magnitude of this sudden change in fCO₂ is equal to approximately half of the annual range of fCO₂ in this area. The air-sea flux estimate for the ~20 day experiment using the Wanninkhof (1992) gas transfer velocity formulation was -0.012 mol m^-2 d^-1 and using the Liss and Merlivat (1986) formulation was -0.007 mol m^-2 d^-1. The storm event, lasting three to four days, accounted for ~38% of the flux over this period. Approximately 16 hours after the onset of the storm, there was an increase in surface fluorescence coincident with the initial increase in fCO₂. Nitrate measurements made from the ship in the eddy show a sharp peak in surface concentrations ~24 hours after the increase in winds and ~6-8 hours after the increase in surface fluorescence. After the upwelling of the NO₃ the fluorescence increases more sharply while the fCO₂ decreases, consistent with biological productivity. The surface fluorescence measurements remain higher than prestorm conditions for ~5 days after the NO₃ has disappeared.

Humphrey, J.C., J. Absten, S.L. Vargo, J.C. Ogden, J.C. Hendee, T.A. Nelsen, D. Danaher, C.L. Jeffris, and D. Burwell. SEAKEYS: Florida Keys monitoring initiative. Proceedings, 2001 Florida Bay and Adjacent Marine Systems Science Conference, Key Largo, FL, April 23-26, 2001. University of Florida, 87-88 (2001).

The Sustained Ecological Research Related to the Management of the Florida Keys Seascape (SEAKEYS) program was organized in 1991 by the Florida Institute of Oceanography with initial funding from the John D. and Catherine T. MacArthur Foundation, and has been maintained through continuing support provided by the South Florida Ecosystem Restoration, Prediction and Monitoring program, administered by the National Oceanic and Atmospheric Administration (NOAA). The SEAKEYS environmental monitoring program was designed to provide data for a long-term database of meteorological and oceanographic data from the Florida Straits and Florida Bay. The SEAKEYS network provides wind speed, wind gust, air temperature, barometric pressure, sea temperature, and salinity for all stations; and tide level, precipitation, photosynthetically active radiation, fluorometry, and transmissometry for selected stations. These data are transmitted hourly to a GOES satellite, and from there are downloaded for data and information management purposes. SEAKEYS data have been used to characterize the dynamics of several hurricanes since 1992, and have been of great benefit to hurricane forecasters at the National Weather Service and at AOML's Hurricane Research Division in Miami, Florida. Daily data are posted to NOAA's Coral Health and Monitoring Program Web site (http://www.coral.noaa.gov), while historical data are available at http://www.neptune.noaa.gov. These data have also allowed researchers to correlate meteorological and hydrographic dynamics, e.g., El Ni�o/La Ni�a conditions, with environmental changes in Florida Bay and the Florida Keys National Marine Sanctuary.

Jarrell, J.D., M. Mayfield, E.N. Rappaport, and C.W. Landsea. Deadliest, costliest, and most intense United States hurricanes from 1900 to 2000 (and other frequently requested hurricane facts), updated October 2001. NOAA Technical Memorandum, NWS TPC-3 (PB2002-100134), 44 pp. (2001).

This version of the "Deadliest, Costliest, and Most Intense United States Hurricanes from 1900 to 2000" extends the work of Herber et al. (1997) through the 2000 season. It also includes an estimate of the monetary loss that historical hurricanes could exact on the current property-at-risk in the same location.

Johns, E., R.H. Smith, W.D. Wilson, T.N. Lee, and E. Williams. Influence of hurricanes, tropical storms, and cold fronts on south Florida coastal waters. Proceedings, 2001 Florida Bay and Adjacent Marine Systems Science Conference, Key Largo, FL, April 23-26, 2001. University of Florida, 14-15 (2001).

The south Florida climate is characterized by a tropical dry season/wet season pattern, with a wet season typically beginning in June with the onset of summer rainy conditions, and much drier conditions from November to April. The regional climate is also affected in late summer by the passage of tropical cyclones, and in the winter by the passage of cold fronts. These extreme weather events are evident not only in the standard meteorological measurements such as barometric pressure, wind speed and direction, air temperature, and precipitation, but are also manifested in such oceanographic variables as sea surface temperature, sea surface height, current speed and direction, sea surface salinity, and water column turbidity. As part of a joint University of Miami/NOAA project entitled Circulation and exchange of Florida Bay and connecting waters of the Gulf of Mexico and the Florida Keys, a variety of observations have been collected beginning in December 1995. These measurements, which were expanded in scope beginning in September 1997, now include bimonthly interdisciplinary shipboard surveys of salinity, temperature, fluorescence, and nutrients, as well as satellite-tracked surface drifters and moored arrays of currents, temperature, and conductivity. The study area extends from Florida Bay north to Naples, Florida, southwest to the Dry Tortugas, east to Key West and then northeast to Miami, Florida. In addition to the bimonthly surveys, observations are obtained monthly within Florida Bay using a shallow draft catamaran equipped with a continuous flow-through thermosalinograph system. Since 1995, a number of tropical cyclones have come close enough to affect south Florida environmental conditions by means of extreme wind, rain, or both. Although none of these recent tropical cyclones have come close to matching the historically most severe events of the region (e.g., the well-known Labor Day hurricane in 1935, Hurricane Donna in 1960, and Hurricane Andrew in 1992), they still influenced the regional meteorological and oceanographic climate.

Johns, E., P.B. Ortner, R.H. Smith, W.D. Wilson, T.N. Lee, and E. Williams. Salinity variability in Florida Bay from monthly high resolution surveys. Proceedings, 2001 Florida Bay and Adjacent Marine Systems Science Conference, Key Largo, FL, April 23-26, 2001. University of Florida, 16-17 (2001).

As part of NOAA's South Florida Ecosystem Restoration, Prediction and Modeling (SFERPM) program, a time series of high resolution salinity maps of Florida Bay has been obtained using a shallow draft catamaran equipped with a continuous flow-through thermosalinograph system. Each survey is completed within two consecutive days. These maps, produced at an approximately monthly interval from March 1997 to the present, cover the three major subdivisions of Florida Bay, i.e., the northeast Bay, the central Bay, and the western Bay. The three Bay regions respond differently to meteorological and other forcing mechanisms due to their differing degrees of isolation from other coastal waters. For example, the northeast Bay is relatively isolated by the geometry of its coastlines and the shallow mud banks which separate it from the central Bay. The northeast Bay is subject to time-varying inputs of fresh water from the rivers and canals of the Taylor Slough and, as a result, has an extremely large salinity variability related to seasonal and interannual precipitation patterns, as well as to water management practices. On the other hand, the central region of Florida Bay, although also fairly isolated in terms of its topography (except at its southern border where exchange of water with the Atlantic occurs through a few narrow tidal channels between the Florida Keys), has few direct sources of fresh water. Thus, the salinity of the central Bay exhibits a different pattern of variability, responding to the changing balance between local evaporation and precipitation which regularly produces periods of hypersalinity interspersed with much lower salinity periods on a timescale of several months or longer. The persistence of these high or low salinity periods is indicative of long residence times for these basins. Western Florida Bay, on the other hand, has an open western boundary and thus is subject to open exchange of water with the eastern Gulf of Mexico and the southwest Florida shelf. The numerous rivers of the southwest Florida coast, such as the Shark, Broad, and Lostmans Rivers, contribute a time-varying source of fresh water from the Shark River Slough area of the Everglades which at times can flow around Cape Sable and interact with western Florida Bay, providing another source of salinity variability there. Due to the more open exchange with the surrounding Gulf of Mexico and southwest Florida shelf waters, the salinity of the western part of the Bay does not exhibit the long residence times of the northeast and central Bay, but instead can change rather rapidly when influenced by tropical storms, the passage of cold fronts, and other extreme forcing events. Determination of the rates and pathways of exchange between the interior basins of Florida Bay and with the southwest Florida shelf is a critical need for predicting the effects of modifying the fresh water supply to the Everglades as part of the Everglades restoration effort. At present, it is not understood how the proposed changes in water delivery, with increased fresh water flows to the Shark River and Taylor Slough, will affect salinity variability within Florida Bay. However, it is generally agreed that the large seasonal and longer period variations of salinity within the Bay have significant impacts on the sea grass and plankton communities within the Bay, and possibly also with adjacent marine ecosystems of the southwest Florida shelf and the Florida Keys National Marine Sanctuary due to transport processes linking the regions.

Kaplan, J., and M. DeMaria. On the decay of tropical winds after landfall in the New England area. Journal of Applied Meteorology, 40(2):280-286 (2001).

A version of the Kaplan and DeMaria empirical model for predicting the decay of tropical cyclone 1-min maximum sustained surface winds after landfall is developed for the New England region. The original model was developed from the National Hurricane Center (NHC) best-track wind estimates for storms that made landfall in the United States south of 37°N from 1967 to 1993. In this note, a similar model is developed for U.S. storms north of 37°N, which primarily made landfall in New York or Rhode Island and then moved across New England. Because of the less frequent occurrence of New England tropical cyclones, it was necessary to include cases back to 1938 to obtain a reasonable sample size. In addition, because of the faster translational speed and the fairly rapid extratropical transition of the higher-latitude cases, it was necessary to estimate the wind speeds at 2-h intervals after landfall, rather than every 6 h, as in the NHC best track. For the model development, the estimates of the maximum sustained surface winds of nine landfalling storms (seven hurricanes and two tropical storms) at 2-h intervals were determined by an analysis of all available surface data. The wind observations were adjusted to account for variations in anemometer heights, averaging times, and exposures. Results show that the winds in the northern model decayed more (less) rapidly than those of the southern model, when the winds just after landfall are greater (less) than 33 knots. It is hypothesized that this faster rate of decay is due to the higher terrain near the coast for the northern sample and to the more hostile environmental conditions (e.g., higher vertical wind shear). The slower decay rate when the winds fall below 33 knots in the northern model might be due to the availability of a baroclinic energy source as the storms undergo extratropical transition.

Katsaros, K.B. Basin boundaries. In Wind Stress Over the Ocean, I.S.F. Jones and Y. Toba (eds.). Cambridge University Press, 270-275 (2001).

No abstract.

Katsaros, K.B. Evaporation and humidity. In Encyclopedia of Ocean Sciences, J.H. Steele, S.A. Thorpe, and K.K. Turekian (eds.). Academic Press, London, 870-877 (2001).

No abstract.

Katsaros, K.B. Sensors for mean meteorology. In Encyclopedia of Ocean Sciences, J.H. Steele, S.A. Thorpe, and K.K. Turekian (eds.). Academic Press, London, 2744-2751 (2001).

No abstract.

Katsaros, K.B., E.B. Forde, P. Chang, W.T. Liu. QuikSCAT facilitates early identification of tropical depressions in 1999 hurricane season. Geophysical Research Letters, 28(6):1043-1046 (2001).

Far from land and surface ship observations, most tropical depressions are identified by examining images from geostationary satellites for the presence of rotation of the convective cloud masses. During the 1999 hurricane season, surface wind maps obtained by the SeaWinds scatterometer for the tropical Atlantic and Caribbean Sea were examined to test the hypotheses that tropical depressions (TDs) could be observed with this satellite sensor, before identification by the traditional means. SeaWinds was able to detect the presence of tropical depressions by early observations of a closed circulation in the surface winds. The satellite's unprecedented large swath width of 1800 km allows twice a day observation of most of the tropical oceans.

Katzberg, S.J., R.A. Walker, J.H. Roles, T. Lynch, and P.G. Black. First GPS signals reflected from the interior of a tropical storm: Preliminary reults from Hurricane Michael. Geophysical Research Letters, 28(10):1981-1984 (2001).

Using GPS signals reflected from the ocean surface is developing into a simple technique for measuring sea-state and inferring surface wind speeds. Theoretical models have been developed which are considered valid to approximately 24 m/s. The GPS reflection technique has an obvious extension to extremely high sea states, cyclones, and extra-tropical storms. In October 2000, a GPS system mounted in a NOAA hurricane hunter research aircraft was flown into Hurricane Michael off the South Carolina coast. The first acquisition of GPS signals reflected from the sea surface inside tropical cyclones was accomplished. This paper presents some examples of the data sets, as well as early wind speed retrieval results using direct extensions of current models. Data from the GPS wind speed retrievals, as well as from direct aircraft measurements, are compared and discussed.

Knaff, J.A., and C.W. Landsea. Application of the El Ni�o-Southern Oscillation CLImatology and PERsistence (CLIPER) forecasting scheme. Experimental Long-Lead Forecast Bulletin, 10(2):31-34 (2001).

No abstract.

Kollias, P., B.A. Albrecht, and F.D. Marks. Raindrop sorting induced by vertical drafts in convective clouds. Geophysical Research Letters, 28(14):2787-2790 (2001).

Evidence of raindrop sorting by a convective updraft is presented. Using a vertically pointing 94-GHz Doppler radar (lambda = 3.2 mm) and capitalizing on the resonant nature of the backscattering cross-section as a function of the raindrop size (Mie scattering), the vertical air motions to an accuracy of 0.1 m s^-1, and the shape of the raindrop size distribution are retrieved from the Doppler spectra. The interaction of vertical drafts and raindrops is documented for the first time by high resolution radar data. The updraft structure clearly causes horizontal and vertical sorting of the raindrops. In the updraft core, small raindrops (D < 1.7 mm) that have terminal velocities less than the updraft velocities (6-7 m s^-1) and a clear absence of drops > 3 mm are observed. Towards the updraft periphery, a gradual increase in the raindrop sizes is documented where large raindrops (D > 3 mm) are observed. The observations demonstrate the importance of updrafts in distributing the raindrops in space.

Landsea, C.W. Comment on "Changes in the rates of North Atlantic major hurricane activity during the 20th century." Geophysical Research Letters, 28(14):2871-2872 (2001).

No abstract.

Landsea, C.W., and J.A. Knaff. Application of the El Ni�o-Southern Oscillation CLImatology PERsistence (CLIPER) forecasting scheme. Experimental Long-Lead Forecast Bulletin, 10(1):31-33 (2001).

No abstract.

Landsea, C.W., and J.A. Knaff. Application of the El Ni�o-Southern Oscillation CLImatology and PERsistence (CLIPER) forecasting scheme. Experimental Long-Lead Forecast Bulletin, 10(4):41-43 (2001).

No abstract.

Lee, K. Global net community production estimated from the annual cycle of surface water total dissolved inorganic carbon. Limnology and Oceanography, 46(6):1287-1297 (2001).

Global net community production is determined, for the first time, from the decrease in salinity (S)-normalized total dissolved inorganic carbon (NC_T = C_T x 35/S) inventory in the surface mixed layer corrected for changes due to net air-sea CO₂ exchange and diffusive carbon flux from the upper thermocline. Changes in the mixed layer NC_T inventory are estimated using a derived annual cycle of NC_T and global records of the mixed layer depth. The annual NC_T cycle is deduced from regional algorithms relating NC_T to sea surface temperature (SST) and nitrate (NO₃^-), along with global records of seasonal mean SST and NO₃^-, and from the monthly mean surface partial pressure of CO₂ and total alkalinity fields using thermodynamic models. The two methods show similar regional trends and yield global net community production estimates of 6.7 and 8.0 Gt C (1 Gt C = 1 x 10¹² kg carbon), respectively. The two global estimates are not significantly different and represent an eight-month period of 1990 (warming period) during which the mixed layer NC_T concentration decreases. However, the estimates do not account for net community production during a four-month cooling period. Ratios of net community production during the warming and cooling periods are estimated from multiyear sediment trap data at the Hawaii Ocean Time-series (228N, 1588W) and Ocean Weather Station P (50°N, 145°W) sites. Global extrapolation of these ratios yields annual rates of net community production of 9.1 ± 2.7 and 10.8 ± 2.7 Gt C yr^-1.

Lee, T.N., E. Williams, E. Johns, W.D. Wilson, and N.P. Smith. Transport processes linking south Florida coastal ecosystems. In The Everglades, Florida Bay, and Coral Reefs of the Florida Keys: An Ecosystem Sourcebook, K.G. Porter and J.W. Porter (eds.). CRC Press (ISBN 0849320267), 309-342 (2001).

No abstract.

Lindeman, K.C., T.N. Lee, W.D. Wilson, R. Claro, and J.S. Ault. Transport of larvae originating in southwest Cuba and the Dry Tortugas: Evidence for partial retention in grunts and snappers. Proceedings of the Gulf and Caribbean Fisheries Institute, 52:732-747 (2001).

New and existing information was assembled to parameterize forthcoming models examining transport scenarios of larvae spawned within and outside of protected areas of the lower Florida Keys and southwest Cuba. This information suggests that in some valuable fish families, partial retention of larvae frequently occurs in areas often assumed to primarily export spawning products. Four categories of biotic variables were emphasized: locations and timing of spawning, larval durations, growth rates, and larval behaviors. Over 30 spawning aggregation sites for eight snapper species have been tentatively identified. Based on otolith increment counts, mean larval durations ranged from 31-42 d post-fertilization in six snapper species (Lutjanus and Ocyurus) and from 13-20 d in four grunt species (Haemulon and Anisotremus). Behaviors that foster retention may influence recruitment more than larval durations, and vertical and horizontal distributional patterns differ markedly between grunts and snappers. Snapper larvae occur offshore while grunt larvae are rare in offshore or inshore surface waters despite often gregarious settlement events. Based on these information sets, grunt populations my be less subject to advection than snappers. Off southwest Cuba and within the Yucatan channel, many cyclonic and anticyclonic eddies have been recently identified by satellite-tracked drifters and over the horizon radar. Gyres associated with the Dry Tortugas and the Pourtales platform can also be present during spawning seasons. All of these recirculation systems can have residence times exceeding known larval durations. At least four sets of evidence can favor larval retention: (1) the larval biology of grunts practically precludes long-distance transport; (2) the numerous long-term eddy systems off of southwest Cuba; (3) the semi-continuous eddy system in the eastern margin of the Yucatan in the Gulf of Mexico.

Liu, W.T., and K.B. Katsaros. Air-sea fluxes from satellite data. In Ocean Circulation and Climate: Observing and Modeling the Global Ocean, G. Siedler, J. Church, and J. Gould (eds.). Academic Press, 173-180 (2001).

No abstract.

Macdonald, A.M., M.O. Baringer, and A. Ganachaud. Heat transport and climate. In Encyclopedia of Ocean Sciences, J.H. Steele, S.A. Thorpe, and K.K. Turekian (eds), London, Academic Press, Vol. 2, 1195-1206 (2001).

No abstract.

Marks, F.D. Quantitative precipitation forecasting in hurricanes: Issues and opportunities. Preprints, Symposium on Precipitation Extremes: Prediction, Impacts, and Responses, Albuquerque, NM, January 14-19, 2001. American Meteorological Society, Boston, 293-296 (2001).

No abstract.

Mayer, D.A., R.L. Molinari, M.O. Baringer, and G.J. Goni. Transition regions and their role in the relationship between sea surface height and subsurface temperature structure in the Atlantic Ocean. Geophysical Research Letters, 28(20):3943-3946 (2001).

Expendable bathythermograph (XBT) profiles and TOPEX/Poseidon altimeter data (T/P) are compared for the years 1993 through 1997 to determine how much can be understood about water column variability from XBTs given only sea height anomalies (SHA) from T/P. Our focus is on the annual cycle along two well sampled XBT sections in the Atlantic Ocean from 10°S to 40°N. Regions of transition are identified that separate the mid-latitudes where surface buoyancy fluxes dominate the forcing of sea level, from those in the equatorial region where thermocline effects dominate. Zones of transition occur in the vicinity of troughs where small fluctuations in SHA belie the true nature of water column variability. Here, surface and thermocline variability tend to cancel each other. Thus, the character of SHA in transition regions emphasizes how important direct observations can be in interpreting satellite altimetric observations correctly when both surface and thermocline variability are important but are compensating in nature.

McAdie, C.J., P.R. Harasti, P.P. Dodge, W.-C. Lee, S.T. Murillo, and F.D. Marks. Real-time implementation of tropical cyclone-specific radar data processing algorithms. Preprints, 30th International Conference on Radar Meteorology, Munich, Germany, July 19-24, 2001. American Meteorological Society, Boston, 466-468 (2001).

No abstract.

McGillis, W.R., J.B. Edson, J.D. Ware, J.W.H. Dacey, J.E. Hare, C.W. Fairall, and R.H. Wanninkhof. Carbon dioxide flux techniques performed during GasEx-98. Marine Chemistry, 75(4):267-280 (2001).

A comprehensive study of air-sea interactions focused on improving the quantification of CO₂ fluxes and gas transfer velocities was performed within a large open ocean CO₂ sink region in the North Atlantic. This study, GasEx-98, included shipboard measurements of direct covariance CO₂ fluxes, atmospheric CO₂ profiles, atmospheric DMS profiles, water column mass balances of CO₂, and measurements of deliberate SF₆^-3He tracers, along with air-sea momentum, heat, and water vapor fluxes. The large air-sea differences in partial pressure of CO₂ caused by a springtime algal bloom provided high signals for accurate CO₂ flux measurements. Measurements were performed over a wind speed range of 1-16 m s^-1 during the three-week process study. This first comparison between the novel air-side and more conventional water column measurements of air-sea gas transfer show a general agreement between independent air-sea gas flux techniques. These new advances in open ocean air-sea gas flux measurements demonstrate the progress in the ability to quantify air-sea CO₂ fluxes on short time scales. This capability will help improve the understanding of processes controlling the air-sea fluxes which, in turn, will improve our ability to make regional and global CO₂ flux estimates.

Mestas-Nunez, A.M., and D.B. Enfield. Eastern equatorial Pacific SST variability: ENSO and non-ENSO components and their climatic associations. Journal of Climate, 14(3):391-402 (2001).

Using an updated Kaplan et al. global SST anomaly (SSTA) dataset (1870-1999), we construct a canonical representation of El Ni�o-Southern Oscillation (ENSO). When this canonical ENSO is subtracted from the data, we are left with a residual (non-ENSO) dataset for SSTA that includes inter-seasonal to multi-decadal variability. Over the eastern equatorial Pacific (NINO3), the canonical ENSO accounts for about 79% of the total SSTA variability, while the residual, dominated by decadal time scales, accounts for the rest. In particular, about 40-50% of the amplitudes of the strong 1982-1983 and 1997-1998 El Ni�o events were accounted for by the residual variability. The non-ENSO variability is characterized by the known shift from cold to warm in the eastern tropical Pacific in the mid to late 1970s, as well as by a non-stationary interannual variance increase during the 1980s and 1990s. Composite maps of surface (SST, sea level pressure, and winds) and tropospheric (divergent winds, velocity potential, and vertical velocity) variables are used to compare the spatial patterns characterizing the canonical ENSO and the residual components of the NINO3 variability. We find that the residual composites only share large amplitude fluctuations of SST anomalies in the equatorial Pacific east of the dateline. When these composites are separated into decadal and interannual components, the decadal part resembles closely the structure of the Pacific Decadal Oscillation (PDO). The major patterns of tropospheric variability associated with the ENSO and decadal non-ENSO components are quite different. At low latitudes, they imply nearly opposite impacts on far-field regional climates, based on their respective warming (or cooling) phases within the NINO3 region. This unexpected result for low latitude climate associations runs contrary to the naive expectation (recently shown to be true for North America) that a decadally warm tropical east Pacific will reinforce the climate effects associated with ENSO alone. This indicates that in the tropics climate outlooks may be more accurate if based on separately analyzed relationships between these SSTA components and their associated climate fluctuations.

Mestas-Nunez, A.M., D.B. Chelton, and D.B. Enfield. North Pacific circulation variability from TOPEX/POSEIDON sea level observations. Proceedings, 5th Pacific Ocean Remote Sensing Conference (PORSEC), Goa, India, December 5-8, 2000. National Institute of Oceanography, Vol. 1, 263-267 (2001).

We analyze seven years (October 1992-October 1999) of sea level observations from the TOPEX/POSEIDON (T/P) satellite altimeter data to investigate the large-scale ocean circulation variability of the North Pacific from seasonal to interannual time scales. We focus in the mid-latitude western regions and use the T/P observations to estimate the barotropic volume transport variability of the Kuroshio, Oyashio, and Kuroshio Extension currents. We base our transport variability estimates on altimetric sea level differences, and our results agree well with simple wind-driven Sverdrup theory and with a global numerical ocean model simulation.

Michaels, M., M. Shepard, S.D. Aberson, H.A. Friedman, and K. Murphy. Survey results of Society membership: The face of our profession at the threshold of the new millennium. Bulletin of the American Meteorological Society, 82(7):1331-1352 (2001).

In the spring of 1999, the American Meteorological Society surveyed its membership in order to update demographic information on the Society and to gain a more detailed perspective on the workplace. The survey was sent out with the dues statement and was solicited on a separate form returned independently to protect privacy and maintain anonymity. The responses were captured in a newly employed, machine-readable format to provide an ease of statistical analysis and data compilation not available in prior survey analysis. This data collection and subsequent demographic analysis represents the first attempt to update information regarding the membership since the 1993 survey results were published by Zevin and Seitter. The format of the 1999 survey was designed to logically follow and expand upon the historical data of the membership collected at varying intervals since 1975. The 1999 survey was broken into six parts. The sections on demographics, education, and current employment closely followed the previous surveys from 1993 and 1990 to facilitate direct comparisons between historical datasets whenever possible. The last three sections were reworked to elicit more declarative responses regarding personal circumstances, workplace circumstances, and additional issues concerning career choice and AMS membership, respectively. An additional space was provided for narrative comments regarding opportunities for women and minorities in the AMS-related sciences. Some 10,000 members were sent the 1999 dues statement and enclosed survey questionnaire. A total of 4,669 members responded. The following is a detailed analysis of the data collected from the 1999 membership survey.

Mikhin, D. Energy-conserving and reciprocal solutions for higher-order parabolic equations. Journal of Computational Acoustics, 9(1):183-203 (2001).

The energy conservation law and the flow reversal theorem are valid for underwater acoustic fields. In media at rest the theorem transforms into well-known reciprocity principle. The presented parabolic equation (PE) model strictly preserves these important physical properties in the numerical solution. The new PE is obtained from the one-way wave equation by Godin via Pade approximation of the square root operator and generalized to the case of moving media. The PE is range-dependent and explicitly includes range derivatives of the medium parameters. Implicit finite difference scheme solves the PE written in terms of energy flux. Such formalism inherently provides simple and exact energy-conserving boundary condition at vertical interfaces. The finite-difference operators, the discreet boundary conditions, and the self-starter are derived by discretization of the differential PE. Discreet energy conservation and flow reversal theorem are rigorously proved as mathematical properties of the finite-difference scheme and confirmed by numerical modeling. Numerical solution is shown to be reciprocal with accuracy of 10-12 decimal digits, which is the accuracy of round-off errors. Energy conservation and wide-angle capabilities of the model are illustrated by comparison with two-way normal mode solutions including the ASA benchmark wedge.

Millero, F.J., W.T. Hiscock, F. Huang, M. Roche, and J.-Z. Zhang. Seasonal variation of the carbonate system in Florida Bay. Bulletin of Marine Science, 68(1):101-123 (2001).

The carbonate system has been studied in the Florida Bay from 1997 to 2000. Measurements of pH, total alkalinity (TA), and total inorganic carbon dioxide (TCO₂) were made from 20 stations in the Bay and used to calculate the partial pressure of carbon dioxide (pCO₂) and the saturation states of aragonite (OMEGA_Arg) and calcite (OMEGA_Cal). The results were found to correlate with the salinity. The pH was low and the pCO₂ was high for the freshwater input from the mangrove fringe due to the photochemical and biological oxidation of organic material. The TA and TCO₂ for the freshwater input are higher than seawater due to the low values of pH and OMEGA. The pH was high and the pCO₂ was low in November in regions where the chlorophyll is high due to biological production. During the summer when the salinity is the highest, the normalized values of TA and TCO₂ were lower than average seawater, due to the inorganic precipitation of CaCO₃ caused by the resuspension of sediments or the biological loss by macroalgae. A transect across the mangrove fringe near the outflow of Taylor Slough shows that PO₄ and TA increases as the freshwater enters the Bay. This is thought to be due to the dissolution of CaCO₃ in the low pH waters from the bacterial and photo oxidation of plant material.

Millero, F.J., F. Huang, X. Zhu, X. Liu, and J.-Z. Zhang. Adsorption and desorption of phosphate on the calcite and aragonite in seawater. Aquatic Geochemistry, 7(1):33-56 (2001).

The adsorption and desorption of phosphate on calcite and aragonite were investigated as a function of temperature (5-45°C) and salinity (0-40) in seawater pre-equilibrated with CaCO₃. An increase in temperature increased the equilibrium adsorption; whereas an increase in salinity decreased the adsorption. Adsorption measurements made in NaCl were lower than the results in seawater. The higher values in seawater were due to the presence of Mg²⁺ and Ca²⁺ ions. The increase was five times greater for Ca²⁺ than Mg²⁺. The effects of Ca²⁺ and Mg²⁺ are diminished with the addition of SO₄^2-, apparently due to the formation of MgSO₄ and CaSO₄ complexes in solution and/or SO₄^2- adsorption on the surface of CaCO₃. The adsorbed Ca²⁺ and Mg²⁺ on CaCO₃ (at carbonate sites) may act as bridges to PO₄^3- ions. The bridging effect of Ca²⁺ is greater than Mg²⁺, apparently due to the stronger interactions of Ca²⁺ with PO₄^3-. The apparent effect of salinity on the adsorption of PO₄ was largely due to changes in the concentration of HCO₃^- in the solutions. An increase in the concentration of HCO₃^- caused the adsorption of phosphate to decrease, especially at low salinities. The adsorption at the same level of HCO₃^- (2 mM) was nearly independent of salinity. All of the adsorption measurements were modeled empirically using a Langmuir-type adsorption isotherm [[PO₄]_ad = K_m C_m [PO₄]_T /(1 + K_m [PO₄]_T)], where [PO₄]_ad and [PO₄]_T are the adsorbed and total dissolved phosphate concentrations, respectively. The values of C_m (the maximum monolayer adsorption capacity, mol/g) and K_m (the adsorption equilibrium constant, g/(mol)) over the entire temperature (t, °C) and salinity (S) range were fitted to [C_m = 17.067 + 0.1707t - 0.4693S + 0.0082S² (sigma = 0.7)] [ln K_m = -2.412 + 0.0165t - 0.0004St - 0.0008S² (sigma = 0.1)]. These empirical equations reproduce all of our measurements of [PO₄]_ad up to 14 µmol/g and within �0.7 µmol/g. The kinetic data showed that the phosphate uptake on carbonate minerals appears to be a multi-step process. Both the adsorption and desorption were quite fast in the first stage (less than 30 min) followed by a much slower process (lasting more than one week). Our results indicate that within 24 hours aragonite has a higher sorption capacity than calcite. The differences between calcite and aragonite become smaller with time. Consequently, the mineral composition of the sediments may affect the short-term phosphate adsorption and desorption on calcium carbonate. Up to 80% of the adsorbed phosphate is released from calcium carbonate over one day. The amount of PO₄ left on the CaCO₃ is close to the equilibrium adsorption. The release of PO₄ from calcite is faster than from aragonite. Measurements with Florida Bay sediments produced results between those for calcite and aragonite. Our results indicate that the calcium carbonate can be both a sink and source of phosphate in natural waters.

Morisseau-Leroy, N., M.K. Solomon, and G.P. Momplaisir. Oracle 9i SQLI Programming. McGraw-Hill (ISBN 0072190930), 687 pp. (2001).

No abstract.

Murillo, S.T., W.-C. Lee, F.D. Marks, and P.P. Dodge. Using a single-Doppler radar wind retrieval technique to examine structural changes in Hurricane Danny (1997). Preprints, 30th International Conference on Radar Meteorology, Munich, Germany, July 19-24, 2001. American Meteorological Society, Boston, 148-149 (2001).

No abstract.

Nelsen, T.A., G. Garte, C. Featherstone, H.R. Wanless, J.H. Trefry, W.-J. Kang, S. Metz, C. Alvarez-Zarikian, T. Hood, P. Swart, G. Ellis, P. Blackwelder, L. Tedesco, C. Slouch, J.F. Pachut, and M. O'Neal. Linkages between the south Florida peninsula and coastal zone: A sediment-based history of natural and anthropogenic influences. In The Everglades, Florida Bay, and Coral Reefs of the Florida Keys: An Ecosystem Sourcebook, K.G. Porter and J.W. Porter (eds.). CRC Press (ISBN 0849320267), 415-449 (2001).

No abstract.

Ochoa, J., J. Sheinbaum, A. Badan, J. Candela, and W.D. Wilson. Geostrophy via potential vorticity inversion in the Yucatan Channel. Journal of Marine Research, 59(5):725-747 (2001).

It has become common practice to measure ocean current velocities together with the hydrography by lowering an ADCP on typical CTD casts. The velocities and densities thus observed are considered to consist mostly of a background contribution in geostrophic balance, plus internal waves and tides. A method to infer the geostrophic component by inverting the linearized potential vorticity (P_V) provides plausible geostrophic density and velocity distributions. The method extracts the geostrophic balance closest to the measurements by minimizing the energy involved in the difference, supposed to consist of P_V-free anomalies. The boundary conditions and the retention of P_V by the geostrophic estimates follow directly from the optimization, which is based on simple linear dynamics and avoids both the use of the thermal wind equation on the measured density, and the classical problem of a reference velocity. By construction, the transport in geostrophic balance equals the measured one. Tides are the largest source of error in the calculation. The method is applied to six ADCP/CTD surveys made across the Yucatan Channel in the springs of 1997 and 1998 and in the winter of 1998-1999. Although the time interval between sections is sometimes close to one inertial period, large variations on the order of 10% are found from one section to the next. Transports range from 20 to 31 Sv with a net average close to 25 Sv, consisting of 33 Sv of inflow into the Gulf of Mexico and 8 Sv of outflow into the Caribbean Sea. The highest velocities are 2.0 m sec^-1 into the Gulf of Mexico near the surface on the western side of the channel, decreasing to 0.1 m sec^-1 by 400 to 500 m depth. Beneath the core of the Yucatan Current a countercurrent, with speeds close to 0.2 m sec^-1 and an average transport of 2 Sv, hugs the slopes of the channel from 500 to 1500 m depth. Our data show an additional 6 Sv of return flow within the same depth range over the abrupt slope near Cuba, which is likely to be the recirculating fraction of the Yucatan Current deep extension, unable to outflow through the Florida Straits. The most significant southerly flows do not occur in the deepest portion of the channel, but at depths around 1000 m.

Ooyama, K.V. A dynamic and thermodynamic foundation for modeling the moist atmosphere with parameterized microphyics. Journal of the Atmospheric Sciences, 58(15):2073-2102 (2001).

Moist convection is an exquisite yet powerful participant in the creation of weather on our planet. To facilitate numerical modeling of weather systems in a moist atmosphere, a direct and consistent application of dynamic and thermodynamic principles, in conjunction with parameterized microphysics, is proposed. An earlier formulation of reversible thermodynamics, in terms of the mass of air and water substance and the total entropy, is now extended to include the irreversible process of precipitation through parameterized microphysics. The dynamic equations are also formulated to account consistently for the mass and momentum of precipitation. The theoretical proposal is tested with a two-dimensional model that utilizes a versatile and accurate spectral method based on a cubic-spline representation of the spatial fields. In order to allow a wide range of scale interactions, the model is configured on multiply-nested domains of outwardly decreasing resolution, with noise-free, two-way interfaces. The semi-implicit method provides efficient time integration for the nested spectral model. The tests performed are the simulation of the growth of single-cell clouds and also the generation of self-sustaining multicell squall lines, and the effects of various resolutions on the simulations are examined. The results favorably compare with similar results found in the literature, but also offer new insights into the interplay between dynamics and precipitation.

Ortner, P.B., L.C. Hill, M.J. Dagg, J. Rabelais, and G. Thayer. Mesozooplankton abundance variability within Florida Bay (1994-2000). Proceedings, 2001 Florida Bay and Adjacent Marine Systems Science Conference, Key Largo, FL, April 23-26, 2001. University of Florida, 195-196 (2001).

Since 1994, NOAA's South Florida Ecosystem Restoration Prediction and Modeling (SFERPM) program has supported regular monitoring of plankton populations in Florida Bay and adjacent coastal waters along the west Florida shelf and seaward of the Florida Keys. One reason is that the zooplankton of Florida Bay had received comparatively little attention prior to this work with not a single published report quantitatively characterizing the resident population. Another impetus for doing so was the relationship between zooplankton grazing and phytoplankton blooms. However, bloom incidence might be but one aspect of a more general phenomenon, ecosystem shift, and habitat change. A change of state in the Bay ecosystem could have enormous consequence to the commercially and recreationally significant living resources to which the Bay represents a nursery ground and was, therefore, a particularly important issue to NOAA. Initial results supported this notion. However, as additional data have accumulated, we now have little doubt that these initial hypotheses were over simplified. The ecosystem in Florida Bay does not appear to be undergoing a monotonic change to a more pelagic state. In this respect, the results appear consistent with the SERC surveys indicating that over the same time period plankton blooms have, in general, not systematically increased throughout Florida Bay. By coincidence, we may have initiated our study close to the apex of phytoplankton bloom intensity. Based on enumerations from 64 µm net tows, the abundance of copepods and other holoplanktonic macroplankton was moderate in the fall of 1994 through mid-winter 1995 but declined markedly thereafter to exceedingly low levels until ca. spring 1996 when it returned to similar levels. Thereafter to the present, it has increased markedly. Taxa vary but values more than five times higher than those present in 1994 have become common. The increase has occurred without any apparent increase in their apparent food source, the phytoplankton. This is not surprising, however. In shallow subtropical estuaries such as Florida Bay, a substantial fraction of the trophic base supporting zooplankton populations may be derived from primary production by seagrass and benthic algae rather than phytoplankton, vitiating any direct positive relationship between the abundances of zooplankton and phytoplankton. Interestingly, a similar trend was observed in the western, central, and eastern regions of the Bay despite their systematic differences in salinity, water column chlorophyll, bloom incidence, etc. In contrast, the abundance of a dominant water column planktivore, Anchovia mitchelli, the bay anchovy, varied almost inversely with the abundance of its prey. Bay anchovy abundance in the same regions was high until 1996, when it dominated the forage fish community, but has declined precipitously thereafter to levels observed during the mid-1980s. However, sampling has been insufficient to provide rigorous estimates of bay anchovy abundance. Concentrations sufficient to appreciably reduce zooplankton numbers were observed with some regularity. In short, the recent history of phytoplankton, zooplankton, and planktivorous fish abundance provides little or no support for the concept of a fundamental persistent Bay shift from a demersal benthic production-based ecosystem to a pelagic water column production-based ecosystem.

Peltola, E., K. Lee, R.H. Wanninkhof, R. Feely, M. Roberts, D. Greeley, M.O. Baringer, G. Johnson, J. Bullister, C. Mordy, J.-Z. Zhang, P. Quay, F. Millero, D. Hansell, and P. Minnett. Chemical and hydrographic measurements on a Climate and Global Change Cruise along 24°N in the Atlantic Ocean WOCE Section A5R (repeat) during January-February 1998. NOAA Data Report, OAR AOML-41 (PB2001-107645), 210 pp. (2001).

This document contains data and metadata from a zonal cruise along nominally 24.5°N in the Atlantic Ocean from Las Palmas, Canary Islands in Spain to Miami, Florida. The cruise took place from January 23 to February 24, 1998 aboard the NOAA Ship Ronald H. Brown under auspices of the National Oceanic and Atmospheric Administration (NOAA). This report presents the analytical and quality control procedures performed during the cruise and bottle data from the cruise. The research was sponsored by the NOAA Climate and Global Change Program under: (i) The Ocean-Atmosphere Carbon Exchange Study (OACES); and (ii) the World Ocean Circulation Experiment (WOCE) repeat hydrography program. Samples were taken from up to 36 depths at 130 stations. The data presented in this report includes the analyses of water samples for: salinity, nutrients, total dissolved inorganic carbon dioxide (DIC), fugacity of carbon dioxide (fCO₂), total alkalinity (TA), pH, total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), chlorofluorocarbons, and stable carbon isotopic ratio of DIC (¹³C/¹²C). Basic hydrographic parameters, pressure, CTD salinity, temperature and the calculated potential temperature, and potential density are included as well.

Phoebus, P.A., D.R. Smith, P.J. Croft, H.A. Friedman, M.C. Hayes, K.A. Murphy, M.K. Ramamurthy, B. Watkins, and J.W. Zeitler. Meeting summary: Ninth AMS symposium of education. Bulletin of the American Meteorological Society, 82(2):295-303 (2001).

The American Meteorological Society held its Ninth Symposium on Education in conjunction with the 80th Annual Meeting in Long Beach, California. The theme of this year's symposium was "Atmospheric and Oceanographic Education-Expanding our Vision for the New Millennium." Thirty-five oral presentations and 53 poster presentations summarized a variety of educational programs or examined educational issues for both the precollege and university levels. There was a special session reporting on a recent survey conducted by the Board on Women and Minorities, as well as a special session on the educational applications of satellite meteorology and oceanography. Over 200 people representing a wide spectrum of the Society attended one or more of the sessions in this two-day conference. The program for the Ninth Symposium on Education can be viewed in the October 1999 issue of the Bulletin.

Pinker, R.T., K.B. Katsaros, and B. Zhang. Prospects for satellite estimates of net air-sea flux. Proceedings, Intercomparison and Validation of Ocean-Atmosphere Flux Fields Workshop, Potomac, MD, May 21-24, 2001. WCRP-115-WMO/TD-No. 1083, 223-227 (2001).

No abstract.

Powell, M.D., and S.D. Aberson. Accuracy of United States tropical cyclone landfall forecasts in the Atlantic Basin (1976-2000). Bulletin of the American Meteorological Society, 82(12):2749-2768 (2001).

About 13% of all Atlantic basin tropical cyclone forecasts issued from 1976 to 2000 are for landfalls along the United States coastline, and 2% more are for storms forecast to make landfall in the United States but that remain at sea. Landfall position and time forecasts are skillful at all forecast time periods and are more skillful than Atlantic basin track forecasts as a whole, but within 30 h of predicted landfall, timing errors demonstrate an early bias of 1.5-2.5 h. Landfall forecasts are most accurate for storms moving at oblique or normal angles to the coastline and slow-moving storms. During the last quarter century, after adjustment for forecast difficulty, no statistically significant improvement or degradation is noted for landfall position forecasts. Time of landfall forecasts indicate no degradation at any period and significant improvement for the 19-30 h period. The early bias and lack of improvement are consistent with a conservative or "least regret" forecast and warning strategy to account for possible storm accelerations. Landfall timing uncertainty is ~11 h at 24 and 36 h, which suggests that hurricane warnings could be disseminated about 12 h earlier (at 36 h, rather than 24 h, before predicted landfall) without substantial loss of lead time accuracy (although warning areas necessarily would be larger). Reconsideration of the National Weather Service Strategic Plan and United States Weather Research Program track forecast goals is recommended in light of these results.

Reasor, P.D., and M.T. Montgomery. Three-dimensional alignment and corotation of weak, TC-like vortices via linear vortex Rossby waves. Journal of the Atmospheric Sciences, 58(16):2306-2330 (2001).

The vertical alignment of an initially tilted geostrophic vortex is shown here to be captured by linear vortex Rossby wave dynamics when the vortex cores at upper and lower levels overlap. The vortex beta Rossby number, defined as the ratio of nonlinear advection in the potential vorticity equation to linear radial advection, is less than unity in this case. A useful means of characterizing a tilted vortex flow in this parameter regime is through a wave-mean flow decomposition. From this perspective, the alignment mechanism is elucidated using a quasigeostrophic model in both its complete and linear equivalent barotropic forms. Attention is focused on basic-state vortices with continuous and monotonically decreasing potential vorticity profiles. For internal Rossby deformation radii larger than the horizontal scale of the tilted vortex, an azimuthal wavenumber 1 quasi mode exists. The quasi mode is characterized by its steady cyclonic propagation, long lifetime, and resistance to differential rotation, behaving much like a discrete vortex Rossby wave. The quasi mode traps disturbance energy, causing the vortex to precess, or corotate, and thus prevents alignment. For internal deformation radii smaller than the horizontal vortex scale, the quasi mode disappears into the continuous spectrum of vortex Rossby waves. Alignment then proceeds through the irreversible redistribution of potential vorticity by the sheared vortex Rossby waves. Further decreases in the internal deformation radius result in a decreased dependence of vortex evolution on initial tilt magnitude, consistent with a reduction of the vortex beta Rossby number. These results are believed to have relevance to the problem of tropical cyclone (TC) genesis. Cyclogenesis initiated through the merger and alignment of low-level convectively generated positive potential vorticity within a weak incipient vortex is captured by quasi-linear dynamics. A potential dynamical barrier to TC development in which the quasi mode frustrates vertical alignment can be identified using the linear alignment theory in this case.

Reasor, P.D., M.T. Montgomery, F.D. Marks, and J.G. Gamache. Studies of tropical cyclone vorticity dynamics using airborne Doppler-derived wind fields. Preprints, 30th International Conference on Radar Meteorology, Munich, Germany, July 19-24, 2001. American Meteorological Society, Boston, 142-144 (2001).

No abstract.

Rizzoli, P., A. Busalacchi, R. Fine, J. McCreary, R.L. Molinari, and F. Schott. Meeting summary: CLIVAR workshop on shallow tropical-subtropical overturning cells (STCs) and their interaction with the atmosphere: Venice, Italy, 9-13 October 2000. Bulletin of the American Meteorological Society, 82(12):2815-2816 (2001).

No abstract.

Roemmich, D., O. Boebel, Y. Desaubies, H. Freeland, K. Kim, B. King, P.-Y. LeTraon, R.L. Molinari, W.B. Owens, S. Riser, U. Send, K. Takeuchi, and S. Wijffels (Argo Science Team). Argo: The global array of profiling floats. In Observing the Oceans in the 21st Century, C.J. Koblinsky and N. Smith (eds.). Australian Bureau of Meteorology, 248-258 (2001).

The Argo network of autonomous profiling floats will provide the first global views of the time-varying temperature (T) and salinity (S) fields of the upper ocean. Argo will serve a broad community of scientific and operational users, with objectives falling into several categories. It will provide a quantitative description of the evolving physical state of the upper ocean and the patterns of ocean climate variability, including heat and freshwater storage and transport. The data will enhance the value of the Jason altimeter through measurement of the subsurface vertical structure of T and S, plus reference velocity, with sufficient coverage and resolution for interpreting altimetric sea surface height variability. Argo data will be used for initializing ocean and coupled forecast models, for data assimilation and for dynamical model testing. A primary focus of Argo is seasonal-to-decadal climate variability and predictability, but many applications for high-quality global ocean analyses are anticipated. The initial design of the Argo network is based on experience from the present observing system, on newly gained knowledge of variability from the TOPEX/Poseidon altimeter, and on estimated requirements for climate and high-resolution ocean models. Argo will provide 100 000 T-S profiles and reference velocity measurements per year from about 3000 floats distributed over the global oceans at 3-degree spacing. Floats will cycle to 2000 m depth every 10 days, with a 4-5 year lifetime for individual instruments. All Argo data will be publicly available in near real-time via the Global Telecommunications System (GTS), and in scientifically quality-controlled form with a few months delay. Global coverage will be achieved during the Global Ocean Data Assimilation Experiment (GODAE, 2003-2005), which together with the Climate Variability and Predictability Programme (CLIVAR) and the Global Climate Observing System/Global Ocean Observing System (GCOS/GOOS), provide the major scientific and operational impetus for Argo.The design emphasizes the need to integrate Argo within the overall framework of a comprehensive ocean observing system. International planning for Argo, including sampling and technical issues, is coordinated by the Argo Science Team (www-argo.ucsd.edu). Nations presently having Argo plans that include float procurement or production include Australia, Canada, China, France, Denmark, Germany, India, Japan, the Republic of Korea, New Zealand, Spain, the UK, and the USA, plus a European Union proposal. Combined deployments from these nations may exceed 700 floats per year as early as 2003. Broad participation in Argo by many nations is anticipated and encouraged either through float procurement, logistical support for float deployment, or through analysis and assimilation of Argo data.

Rogers, R.F., and J.M. Fritsch. Surface cyclogenesis from convectively-driven amplification of mid-level mesoscale convective vortices. Monthly Weather Review, 129(4):605-637 (2001).

Mesoscale convective vortices (MCVs) are mid-tropospheric warm-core cyclonic circulations that often develop in the stratiform region of mesoscale convective systems. Typically, divergent, anticyclonically-circulating, mesoscale cold anomalies appear both above and below the MCV. The upper level cold anomaly is usually found near the tropopause while the low-level anomaly is surface-based and exhibits locally higher pressure. One aspect of MCVs that has received much attention recently is the role that they may play in tropical cyclogenesis. Of special interest is how an MCV amplifies when deep convection redevelops within the borders of its mid-level cyclonic circulation and how the amplified MCV transforms the divergent surface-based cold pool with anomalously high surface pressure into a convergent cyclonic circulation with anomalously low pressure. The Pennsylvania State University/National Center for Atmospheric Research mesoscale model MM5 is used to simulate an MCV that was instrumental in initiating, within the borders of the mid-level vortex's circulation, several successive cycles of convective development and decay over a two-day period. After each cycle of convection, both the horizontal size of the cyclonic circulation and the magnitude of the potential vorticity associated with the vortex were observed to increase. The simulation reproduces the development and evolution of the MCV and associated convective cycles. Mesoscale features responsible for the initiation of convection within the circulation of the vortex and the impact of this convection on the structure and evolution of the vortex are investigated. A conceptual model is presented to explain how convective redevelopment within the MCV causes low-level heights to fall and cyclonic vorticity to grow downward to the surface. Applying this conceptual model to a tropical marine environment is also considered.

Rogers, R.F., S.S. Chen, J.E. Tenerelli, and H.E. Willoughby. A numerical study of the impact of vertical shear on the distribution of rainfall in Hurricane Bonnie (1998). Preprints, Ninth Conference on Mesoscale Processes, Ft. Lauderdale, FL, July 30-August 2, 2001. American Meteorological Society, Boston (2001).

No abstract.

Sainz-Trapaga, S.M., G.J. Goni, and T. Sugimoto. Identification of the Kuroshio Extension, its bifurcation and northern branch from altimetry and hydrographic data during October 1992-August 1999: Spatial and temporal variability. Geophysical Research Letters, 28(9):1759-1762 (2001).

A methodology is proposed using altimeter-derived upper layer thickness and baroclinic transport to identify the Kuroshio Extension, the Bifurcation Point, and the Northern Branch, by combining TOPEX/POSEIDON altimeter and climatological data within a two-layer reduced gravity model. Results obtained from the Japanese coast to 175°W show that the location of the Bifurcation Point presents interannual variability that is related with upstream conditions. The longitude of the Bifurcation Point ranged from 147 to 160°E. Estimates of baroclinic transport at the Kuroshio Extension and its Northern Branch decrease steadily to the east trough, the region of study from 35 to 11 and from 10 to 3 Sv, respectively.

Schmid, C., R.L. Molinari, and S.L. Garzoli. New observations of the intermediate depth circulation in the tropical Atlantic. Journal of Marine Research, 59(2):281-312 (2001).

The intermediate depth (around 1000 m) circulation in the interior tropical Atlantic has been described as several narrow flow bands. Due to a lack of data, these currents have previously only been poorly resolved in space and time. Recent observations, obtained during the mid-1997 Seward Johnson cruise and from PALACE floats which cover the period summer 1997 to spring 2000, allow a more detailed description of the intermediate depth circulation in the tropical Atlantic. The PALACE trajectories display several well defined currents between the equator and 4°N at 800 to 1100 m. Two regimes separated by the eastern edge of the Mid-Atlantic Ridge seem to exist at these latitudes. Velocities in the eastern regime are lower than in the western regime and, at some latitudes, the zonal flow in the two regimes is going in opposite directions. Farther south, between 4°S and 2°S, westward velocities of the central South Equatorial Current dominate the circulation. The flow north of 4°N and south of 4°S is governed by up to several month-long periods of eastward or westward flow, with only weak preferences for either direction. The southern region is characterized by the (meandering) transition between the central South Equatorial Current and the South Equatorial Countercurrent. It has been proposed earlier that these two currents do not extend eastward beyond about 10°W, and that the intermediate water follows a cyclonic path east of 10°W between about 5°S and 25°S. This could be interpreted as an intermediate expression of the Angola Gyre. Such a circulation is not found in the present data set. It is also noted that no significant cross-equatorial flow is found in the PALACE data.

Schubert, W.H., S.A. Hausman, M. Garcia, K.V. Ooyama and H.-C. Kuo. Potential vorticity in a moist atmosphere. Journal of the Atmospheric Sciences, 58(21):3148-3157 (2001).

The potential vorticity principle for a nonhydrostatic, moist, precipitating atmosphere is derived. An appropriate generalization of the well-known (dry) Ertel potential vorticity is found to be P = rho^-1 (2OMEGA + gradient x u) • gradient theta_rho, where rho is the total density, consisting of the sum of the densities of dry air, airborne moisture (vapor and cloud condensate), and precipitation; u is the velocity of the dry air and airborne moisture; and theta_rho = T_rho (p₀/p)^Ra/CPa is the virtual potential temperature, with T_rho = p/(rho R_a) the virtual temperature, p the total pressure (the sum of the partial pressures of dry air and water vapor), p₀ the constant reference pressure, R_a the gas constant for dry air, and C_Pa the specific heat at constant pressure for dry air. Since theta_rho is a function of total density and total pressure only, its use as the thermodynamic variable in P leads to the annihilation of the solenoidal term, that is, gradient theta_rho • (gradient_rho × gradient_p) = 0. In the special case of an absolutely dry atmosphere, P reduces to the usual (dry) Ertel potential vorticity. For balanced flows, there exists an invertibility principle that determines the balanced mass and wind fields from the spatial distribution of P. It is the existence of this invertibility principle that makes P such a fundamentally important dynamical variable. In other words, P (in conjunction with the boundary conditions associated with the invertibility principle) carries all the essential dynamical information about the slowly evolving balanced part of the flow.

Smith, D.R., M.C. Hayes, M.K. Ramamurthy, J.W. Zeitler, K.A. Murphy, P.J. Croft, J.M. Nese, H.A. Friedman, H.W. Robinson, C.D. Thormeyer, P.A. Ruscher, and R.E. Pandya. Meeting summary: 10th AMS symposium on education. Bulletin of the American Meteorological Society, 82(12):2817-2824 (2001).

The American Meteorological Society held its 10th Symposium on Education in conjunction with the 82nd Annual Meeting in Albuquerque, New Mexico. The theme of 2001's symposium was "enhancing public awareness of the atmospheric and oceanic environments." Thirty-six oral presentations and 38 poster presentations summarized a variety of educational programs or examined educational issues at both the precollege and university levels. There was a special session on increasing awareness of meteorology and oceanography through popular and informal educational activities, as well as a joint session with the 17th International Conference on Interactive Information and Processing Systems (IIPS) for Meteorology, Oceanography, and Hydrology on using the World Wide Web to deliver information pertaining to the atmosphere, oceans, and coastal zone. Over 200 people representing a wide spectrum of the Society attended one or more of the sessions in this two-day conference. The program for the 10th Symposium on Education can be viewed in the November 2000 issue of the Bulletin.

Smith, R.H., E. Johns, W.D. Wilson, T.N. Lee, and E. Williams. Moored observations of salinity variability in Florida Bay and south Florida coastal waters on daily to interannual time scales. Proceedings, 2001 Florida Bay and Adjacent Marine Systems Science Conference, Key Largo, FL, April 23-26, 2001. University of Florida, 42-43 (2001).

In support of the South Florida Ecosystem Restoration, Prediction, and Modeling Program (SFERPM), a three year, physical oceanographic study of the connectivity between Florida Bay and the surrounding waters of the Gulf of Mexico, the southwest Florida shelf, and the Atlantic Ocean was conducted. The field survey included a moored array equipped with current meters, bottom pressure sensors, and conductivity/temperature sensors, satellite-tracked surface drifters, and bimonthly interdisciplinary shipboard surveys with continuous underway thermosalinograph observations of surface salinity, temperature, and fluorescence. The moored conductivity/temperature array consists of 21 sensors positioned from the Florida Keys reef tract, through western Florida Bay and around Cape Sable, extending northward off the mouths of the Shark, Broad, and Lostmans Rivers, to Indian Key just south of Marco Island, Florida. Salinity time series collected from this array are affected by the local precipitation/evaporation balance, riverine discharge from the Everglades which is, in turn, influenced by precipitation as well as anthropogenic factors, fluctuations in the Gulf of Mexico Loop Current, meteorological forcing events such as hurricanes and tropical storms in the summer and cold fronts in the winter, and interannual meteorological events such as El Ni�o. Though the bulk of the array was deployed in late 1997, the effects of the 1997/1998 El Ni�o on the climate patterns of south Florida can be seen throughout the salinity time series. A wet season/dry season reversal is evident in 1998 with salinity minima occurring at our moorings in April (traditionally the most saline period of the year due to dryer, winter weather) and maxima prevalent in late summer (contradictory to typical wet season conditions).

Testud, J., S. Oury, R.A. Black, P. Amayenc, and X. Dou. The concept of "normalized" distribution to describe raindrop spectra: A tool for cloud physics and cloud remote sensing. Journal of Applied Meteorology, 40(6):1118-1140 (2001).

The shape of the drop size distribution (DSD) reflects the physics of rain. The DSD is the result of the microphysical processes that transform the condensed water into rain. The question of the DSD is also central in radar meteorology, because it rules the relationships between the radar reflectivity and the rainfall rate R. Normalizing raindrop spectra is the only way to identify the shape of the distribution. The concept of normalization of DSD developed in this paper is founded upon two reference variables, the liquid water content LWC and the mean volume diameter D_m. It is shown mathematically that it is appropriate to normalize by N₀* proportional to LWC/D_m⁴ with respect to particle concentration and by D_m with respect to drop diameter. Also, N₀* may be defined as the intercept parameter that would have an exponential DSD with the same LWC and D_m as the real one. The major point of the authors' approach is that it is totally free of any assumption about the shape of the DSD. This new normalization has been applied to the airborne microphysical data of the Tropical Ocean and Global Atmosphere-Coupled Ocean Atmosphere Response Experiment (TOGA-COARE) collected by the National Center for Atmospheric Research Electra aircraft. The classification of the TOGA-COARE raindrop spectra into four categories (one stratiform, and three convective [0-10, 10-30, and 30-100 mm h^-1]) allowed the following features to be identified. (1) There is a distinct behavior of N₀* between stratiform and convective rains; typical values are 2.2 × 10⁶ m⁴ for stratiform and 2 × 10⁷ m⁴ for convective. (2) In convective rain, there is a clear trend for D_m to increase with R, but there is no correlation between N₀* and R. (3) The "average" normalized shape of the DSD is remarkably stable among the four rain categories. This normalized shape departs from the exponential, but also from all the analytical shapes considered up to now (e.g., gamma, lognormal, modified gamma). The stability of the normalized DSD shape and the physical variability of N₀* and D_m are discussed in respect to the equilibrium theory of List et al. The stability of the shape implies that two parameters (and only two) are needed to describe the DSD. This stability supports the robustness of rain relations parameterized by N₀*. The same TOGA-COARE dataset is used to check that the rain relations parameterized by N₀* are much less dispersed than the classical ones, even after rain-type classification.

Tokarczyk, R., K.D. Goodwin, and E.S. Saltzman. Methyl bromide loss rate constants in the North Pacific Ocean. Geophysical Research Letters, 28(23):4429-4432 (2001).

The degradation rate constant of CH₃Br in the North Pacific Ocean was measured in surface seawater between September and October 1999, using the stable isotope (¹³CH₃Br) incubation technique. Total degradation rate constants ranged from 0.02-0.43 d^-1, decreasing in colder waters as a result of the temperature-dependence of chemical losses. Biological rate constants ranged from 0.01-0.20 d^-1. In subtropical waters (13-20°N), biological loss rate constants were small compared to chemical loss rate constants. North of Hawaii, biological processes played an increasingly significant role in CH₃Br degradation. In subpolar waters (40-58°N), biological losses dominated the removal of methyl bromide. Comparison of the measured loss rate constants with surface water CH₃Br concentrations suggest that the CH₃Br production rate is higher in warm, low latitude waters than in cold subpolar waters at this time of year. Diel studies revealed a midday maximum in biological degradation of methyl bromide.

Van de Kreeke, M., A.M. Brun, and T.A. Nelsen. Sediment exchange and sources of beach sediment, Costa Banderas, Mexico. Shore and Beach, 69(4):19-24 (2001).

Sediment exchange and sand sources for the beaches at Costa Banderas, Mexico are discussed. The shoreline of Costa Banderas consists of several littoral cells divided by protruding cliffs. Overall, the beach sand is comprised of equal fractions of carbonate and clastic sediment. Little sediment exchanges between adjacent cells. Small streams discharge in many of the littoral cells. At the landward side, cliffs bound many of the cells. Based on analysis of composition and grain size (clastic fraction only) of a large number of sediment samples, it is shown that both streams and cliffs contribute to the clastic fraction of the beach sand. In determining sediment pathways of the clastic sediment from grain-size distributions, use is made of distribution component analysis (DCA). The carbonate sand derives from offshore. Because of their contribution to the beach sediment in developing the upland, attention should be given not to eliminate the supply of sediment by the streams.

Wang, C. A unified oscillator model for the El Ni�o-Southern Oscillation. Journal of Climate, 14(1):98-115 (2001).

The delayed oscillator, the western Pacific oscillator, the recharge-discharge oscillator, and the advective-reflective oscillator have been proposed to interpret the oscillatory nature of the El Ni�o-Southern Oscillation (ENSO). All of these oscillator models assume a positive ocean-atmosphere feedback in the equatorial eastern and central Pacific. The delayed oscillator assumes that the western Pacific is an inactive region and wave reflection at the western boundary provides a negative feedback for the coupled system to oscillate. The western Pacific oscillator emphasizes an active role of the western Pacific in ENSO. The recharge-discharge oscillator argues that discharge and recharge of equatorial heat content cause the coupled system to oscillate. The advective-reflective oscillator emphasizes the importance of zonal advection associated with wave reflection at both the western and eastern boundaries. Motivated by the existence of these different oscillator models, a unified oscillator model is formulated and derived from the dynamics and thermodynamics of the coupled ocean-atmosphere system. Consistent with ENSO anomaly patterns observed in the tropical Pacific, this oscillator model considers sea surface temperature anomalies in the equatorial eastern Pacific, zonal wind stress anomalies in both the equatorial central Pacific and the equatorial western Pacific, and thermocline depth anomalies in the off-equatorial western Pacific. If the western Pacific wind-forced response is neglected, thermocline and zonal wind stress anomalies in the western Pacific are decoupled from the coupled system, and the unified oscillator reduces to the delayed oscillator. If wave reflection at the western boundary is neglected, the unified oscillator reduces to the western Pacific oscillator. The mathematical form of the recharge-discharge oscillator can also be derived from this unified oscillator. Most of the physics of the advective-reflective oscillator are implicitly included in the unified oscillator, and the negative feedback of wave reflection at the eastern boundary is added to the unified oscillator. With appropriate model parameters chosen to be consistent with those of previous oscillator models, the unified oscillator model oscillates on interannual time scales.

Wang, C. On the ENSO mechanisms. Advances in Atmospheric Sciences, 18(5):674-691 (2001).

The El Ni�o-Southern Oscillation (ENSO) is an interannual phenomenon involved in the tropical Pacific Ocean-atmosphere interactions. The oscillatory nature of ENSO requires both positive and negative ocean-atmosphere feedbacks. The positive feedback is dated back to Bjerknes' hypothesis in the 1960s, and different negative feedbacks have been proposed since the 1980s associated with the delayed oscillator, the western Pacific oscillator, the recharge-discharge oscillator, and the advective-reflective oscillator. The delayed oscillator assumes that wave reflection at the western boundary provides a negative feedback for the coupled system to oscillate. The western Pacific oscillator emphasizes equatorial wind in the western Pacific that provides a negative feedback for the coupled system. The recharge-discharge oscillator argues that discharge and recharge of equatorial heat content causes the coupled system to oscillate. The advective-reflective oscillator emphasizes the importance of zonal advection associated with wave reflection at both the western and eastern boundaries. All of these physics are summarized in a unified ENSO oscillator. The delayed oscillator, the western Pacific oscillator, the recharge-discharge oscillator, and the advective-reflective oscillator can be extracted as special cases of the unified oscillator. As suggested by this unified oscillator, all of the previous ENSO oscillator mechanisms may be operating in nature.

Wang, C., and D.B. Enfield. The tropical Western Hemisphere warm pool. Geophysical Research Letters, 28(8):1635-1638 (2001).

The Western Hemisphere warm pool (WHWP) of water warmer than 28.5°C extends from the eastern North Pacific to the Gulf of Mexico and the Caribbean, and at its peak, overlaps with the tropical North Atlantic. It has a large seasonal cycle and its interannual fluctuations of area and intensity are significant. Surface heat fluxes warm the WHWP through the boreal spring to an annual maximum of SST and areal extent in the later summer/early fall, associated with eastern North Pacific and Atlantic hurricane activities and rainfall from northern South America to the southern tier of the United States. SST and area anomalies occur at high temperatures where small changes can have a large impact on tropical convection. Observations suggest that a positive ocean-atmosphere feedback operating through longwave radiation and associated cloudiness is responsible for the WHWP SST anomalies. Associated with an increase in SST anomalies is a decrease in atmospheric sea level pressure anomalies and an anomalous increase in atmospheric convection and cloudiness. The increase in convective activity and cloudiness results in less longwave radiation loss from the surface, which then reinforces SST anomalies.

Wang, C., and R.H. Weisberg. Ocean circulation influences on sea surface temperature in the equatorial central Pacific. Journal of Geophysical Research, 106(C9):19,515-19,526 (2001).

Velocity data from an array of acoustic Doppler current profilers moored about 0, 140°W from May 1990 through June 1991 during the Tropical Instability Wave Experiment are used in conjunction with Tropical Atmosphere Ocean array data and a blended sea surface temperature (SST) product to study the processes that control SST variations. The horizontal velocity data allow us to calculate the vertical velocity component by vertically integrating the continuity equation. Given the three-dimensional temperature flux divergence, we examine the role of the ocean circulation on SST. Upwelling and downwelling are found to be associated with cooling and warming, respectively, suggesting that a vertical velocity component of either sign affects SST. Both the temperature flux divergence and advective formulations for the ocean circulations influence in the temperature budget show times when the ocean circulation appears to provide the primary control on SST and times when this is not the case, with the flux divergence formulation performing better than the advective formulation. Statistically, within a bandwidth encompassing the tropical instability waves and the intraseasonal variations, roughly half of the SST variation is accounted for by the ocean circulation. These results are encouraging, given that data sets with different spatial and temporal scales have been used. They suggest that future field experimentation which utilizes a flux divergence array with velocity and temperature data sampled at the same spatial and temporal scales will yield quantitatively improved results. The analyses also show that the ocean circulation on average provides a cooling effect requiring the net surface heat flux to be positive on average to maintain the mean background state. The cooling effect is mainly controlled by mean ocean circulation and temperature fields.

Wanninkhof, R.H., and P. Liss. SOLAS requirements for the improvement of ocean-atmosphere flux fields. Proceedings, Intercomparison and Validation of Ocean-Atmosphere Flux Fields Workshop, Potomac, MD, May 21-24, 2001. WCRP-115-WMO/TD-No. 1083, 8-9 (2001).

No abstract.

Waworuntu, J.M., S.L. Garzoli, and D.B. Olson. Dynamics of the Makassar Strait. Journal of Marine Research, 59(2):313-325 (2001).

Data collected as part of the Arlindo Project ("Arlindo" is an acronym for Arus Lintas Indonen, meaning "throughflow" in Bahasa Indonesia) from October 1996 through March 1998 are analyzed to study the characteristics of the flow through the the Makassar Strait. Analysis of inverted echo sounders (IES) and bottom pressure data (PIES), combined with TOPEX/POSEIDON satellite-derived sea height anomaly, suggest that a minimum of three-layer approximation is necessary to explain the dynamics of the flow in the Makassar Strait. The simple two-layer model used in several studies of the throughflow is rejected based on total incompatibility with the data sets. A three-layer model with significant contributions by the middle layer provides a consistent interpretataion of PIES and satellite data. Results are interpreted in the framework of the large-scale circulation.

Wilkerson, J.C., and J.R. Proni. Underwater acoustical measurement of wind and rainfall in the Bahamas during Hurricane Irene. Proceedings, 17th International Congress on Acoustics, Rome, Italy, September 2-7, 2001. International Commission for Acoustics, CD-ROM (2001).

Underwater acoustic measurements of wind and rainfall were recorded during passage of Hurricane Irene through the Bahamas using an array of bottom-mounted hydrophones at a depth of 1.5 km. Sound spectrum levels were measured in the range extending from a few tenths of a kilohertz to approximately 50 kHz. Rainfall spectra associated with rain bands in the hurricane were observed to display the same acoustic/dropsize cycle response as reported in the literature for subtropical mesoscale convective systems in coastal ocean regions. Observations from the hydrophone array provided high resolution time series data of both wind and rain fields from which information on the life cycles of wind-rain systems and on the extent of their formation was obtained.

Willoughby, H.E., and R.W. Jones. Nonlinear motion of a barotropic vortex in still air and in an environmental zonal flow. Journal of the Atmospheric Sciences, 58(14):1907-1923 (2001).

This study employs a Vortex Tracking Semispectral (VTSS) model cast in cylindrical coordinates that move with the vortex. Variables are represented spectrally in azimuth only, so that the model becomes a set of linear equations for each azimuthal wavenumber component, forced by the environmental flow and coupled by wave-wave interactions that account for all of the nonlinearity. The vortex is advected by the surrounding wind and propagates when potential vorticity (PV) gradients due to the surrounding flow or the beta effect force wavenumber one (WN1) asymmetries. Nonlinearity generally plays a dissipative role. Although propagation is faster in stronger PV gradients, nonlinear interactions cause the motions due to superposed PV gradients to be slower than the sum of their individual motions. In still air or uniform wind on a beta plane, the wave energy spectrum falls off rapidly with wavenumber. For most situations, the calculations converge for truncation at WN6 on a 4000-km domain. In an anticyclonically sheared environmental zonal flow, the spectrum of asymmetric energy narrows because the WN2 asymmetry is forced directly by the environmental deformation. The deformation-induced asymmetry interferes destructively with WN2 due to internal wave-wave interaction. In a cyclonically sheared zonal flow, the deformation-induced and nonlinearly-induced asymmetries interfere constructively, resulting in a broader spectrum. Energy cascades from WN2 to wavenumbers >2. A reverse cascade also carries energy to WN1, changing the beta gyres and the motion. Consequent perturbation of WN1 leads to slow convergence of the predicted vortex position after 10 simulated days with increasing spectral resolution. When imposed mass sources and sinks are used to supply energy directly to the asymmetries in the middle of the spectrum, similar wave-wave interactions force WN1, leading to a trochoidal vortex track.

Wright, C.W., E.J. Walsh, D. Vandemark, W.B. Krabill, A.W. Garcia, S.H. Houston, M.D. Powell, P.G. Black, and F.D. Marks. Hurricane directional wave spectrum spatial variation in the open ocean. Journal of Physical Oceanography, 31(8):2472-2488 (2001).

The sea surface directional wave spectrum was measured for the first time in all quadrants of a hurricane's inner core over open water. The NASA airborne Scanning Radar Altimeter (SRA) carried aboard one of the NOAA WP-3D hurricane research aircraft at 1.5-km height acquired the open-ocean data on 24 August 1998 when Bonnie, a large hurricane with 1-min sustained surface winds of nearly 50 m s^-1, was about 400 km east of Abaco Island, Bahamas. The NOAA aircraft spent more than five hours within 180 km of the eye and made five eye penetrations. Grayscale coded images of Hurricane Bonnie wave topography include individual waves as high as 19 m peak to trough. The dominant waves generally propagated at significant angles to the downwind direction. At some positions, three different wave fields of comparable energy crossed each other. Partitioning the SRA directional wave spectra enabled determination of the characteristics of the various components of the hurricane wave field and mapping of their spatial variation. A simple model was developed to predict the dominant wave propagation direction.

Zhang, J.-Z. Oxidation of hydrogen sulfide by various oxidants in natural waters. Trends in Geochemistry, 1(2000):53-68 (2001).

This article reviews the literature on the oxidation of H₂S by various oxidants, including oxygen, hydrogen peroxide, iodate, chromate, ferrate, Fe(III) hydroxides, and Mn(IV) oxides, in natural waters. The rates of H₂S oxidation increased with oxidants in an order of chromate, oxygen, hydrogen peroxide, iodate, Fe(III) hydroxides, Mn(IV) oxides, and ferrate. Effect of pH on the rates of oxidation by various oxidants indicated that HS^- is a reactive species while H₂S is less reactive or, in some cases, non-reactive. The oxidation by oxygen has been a subject of extensive studies and its rates have been measured over a wide range of environmental conditions such as pH, temperature, and salinity. Dissolved and particulate metals have a significant effect on the rates of oxidation and the product formation. The reaction conditions and resulting product formation (S, S_n^2-, SO₃^2-, S₂O₃^2- and SO₄^2-) were examined to unravel the reaction pathway.

Zhang, J.-Z., and C.J. Fischer. The role of sediment resuspension in the phosphorus cycle in Florida Bay. Proceedings, 2001 Florida Bay and Adjacent Marine Systems Science Conference, Key Largo, FL, April 23-26, 2001. University of Florida, 98-99 (2001).

The mass mortality of sea grass and frequent algal blooms in Florida Bay are a result of eutrophication. Existing data indicate that phosphorus is the limiting nutrient, while nitrogen is abundant. Therefore, the supply of phosphorus is critical to the onset and persistence of phytoplankton blooms in Florida Bay. Biogenic calcium carbonates are major components of the sediments (>90%) in the Florida Bay. Our studies have shown that phosphorus is strongly adsorbed on the surface of calcium carbonate sediment. Sediments in Florida Bay can easily be suspended by storms and tidal mixing due to shallow water depth (~3 m). Phosphorus cycling processes such as release from adsorption to and coprecipitation with suspended sediment may play an important role in the supply phosphorus to phytoplankton bloom. Our project has been focused on the following three aspects: (1) The time scales of phosphate availability through sediment resuspension in Florida Bay water and kinetic of interaction of sedimentary phosphorus with seawater; (2) the distribution coefficients for phosphorus partitioning between sediment/seawater in Florida Bay; and (3) the reactivity and partitioning of various pools of sedimentary phosphorus in Florida Bay surface sediments.

Zhang, J.-Z., C.J. Fischer, and P.B. Ortner. Continuous flow analysis of phosphate in natural waters using hydrazine as a reductant. International Journal of Environmental Analytical Chemistry, 80(1):61-73 (2001).

The use of hydrazine to reduce 12-molybdophosphoric acid to phosphomolybdenum blue in continuous flow analysis of phosphate in natural water samples is characterized. Using hydrazine in gas-segmented continuous flow phosphate analysis minimizes coating and silicate interference in comparison with using ascorbic acid. The addition of Sb to the molybdate reagent increases sensitivity at temperatures greater than 50°C but causes severe additional coating. The degree of coating was found to be a function of pH. Minimal coatings were achieved at a final solution pH of 0.5. Silicate interference was found to increase dramatically with color development temperature. At room temperature no detectable silicate interference was found. We recommend hydrazine in preference to ascorbic acid for gas-segmented continuous flow phosphate analysis with optimal reaction conditions of room temperature color development and a final solution pH of 0.5.

Zhang, J.-Z., C.R. Kelble, and F.J. Millero. Gas-segmented continuous flow analysis of iron in water with a long liquid waveguide capillary flow cell. Analytica Chimica Acta, 438(1-2):49-57 (2001).

A long liquid waveguide capillary flow cell has been successfully adapted to a gas-segmented continuous flow auto-analyzer for trace analysis of iron in water. The flow cell was made of new material, Teflon AF-2400, which has a refractive index (1.29) lower than water (1.33). Total reflection of light can be achieved provided that the incident angle at each reflection on the water/Teflon interface is greater than the critical angle. Teflon AF-2400 is superior to currently used materials in both refractivity and mechanical stability. This allows for construction of a long liquid waveguide capillary flow cell in a helical, rather than linear shape, with compact dimensions. Since the internal volume of a 2 m-long, 550 µm ID liquid waveguide capillary flow cell is only approximately 0.5 cm³, a small sample volume is required. Utilization of this long flow cell significantly enhances the sensitivity of automated colorimetric analysis of iron by the ferrozine method, allowing for accurate determination of nanomolar concentrations of iron in natural waters. The advantages of this technique are low detection limit (0.1 nM), small sample volume (2 ml), high precision (1%), and automation for rapid analysis of a large number of samples. This technique is applicable to any gas-segmented continuous flow analysis or flow injection analysis with spectrophotometric detection.

Zhang, J.-Z., R.H. Wanninkhof, and K. Lee. Enhanced new production observed from the diurnal cycle of nitrate in an oligotrophic anticyclonic eddy. Geophysical Research Letters, 28(8):1579-1582 (2001).

A diurnal study in an anticyclonic eddy provides the first evidence of nutrient dynamics consistent with the observed trends in solar radiation, oxygen concentration changes, and estimates of the eddy diffusive flux of nitrate from nitracline. A new production rate of 24 mmol C m^-2 d^-1 was determined from nitrate inventory changes at nM levels in the mixed layer using a liquid waveguide technique combined with eddy diffusion estimates across the base of the mixed layer from temporal changes in the vertical penetration of SF₆. The new production supported by nitrate from deepening of the mixed layer after storm events is two times larger than that from the daily diffusive flux. Our results demonstrate that new production in the oligotrophic ocean can be enhanced by a supply of nitrate through the eddy turbulence-induced diffusive flux and entrainment during storms. **2000**

Aberson, S.D. The first three years of operational targeting with the NOAA Gulfstream-IV. Preprints, 4th Symposium on Integrated Observing Systems, Long Beach, CA, January 9-14, 2000. American Meteorological Society, Boston, 198-199 (2000).

No abstract.

Aberson, S.D. Three years of tropical cyclone synoptic surveillance in the Atlantic basin. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 108-109 (2000).

Since 1997, NOAA has performed more than 50 synoptic surveillance missions in the core and environments of tropical cyclones threatening the United States mainland, Puerto Rico, and the Virgin Islands with their G-IV and P3 aircraft. GPS dropwindsonde observations are taken approximately every 250 km along the flight tracks and sent to the National Centers for Environmental Prediction and the National Hurricane Center for incorporation in numerical guidance and for subjective evaluation. The impact of these data on both track and intensity forecasts will be presented. Since small differences in initial conditions are known to grow in the numerical models at different rates, targeting the fastest growing modes has been studied. Results of such targeting, including methods to find target locations and sampling strategies, will be presented.

Aberson, S.D. Woman and minorities in meteorology since 1950. Program of the 80th Annual Meeting and Exhibition, Long Beach, CA, January 9-14, 2000. American Meteorological Society, Boston, 70-71 (2000).

No abstract.

Aberson, S.D. Women's trends: The changing status of women in the profession/society. Preprints, 9th Symposium on Education, Long Beach, CA, January 9-14, 2000. American Meteorological Society, Boston, 70-71 (2000).

No abstract.

Aberson, S.D., and K. Bedka. The operational ensemble of tropical cyclone track guidance at the National Hurricane Center (1976-1998). Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 177-178 (2000).

A suite of operational track forecast models has been run at NHC in support of NHC s task to provide tropical cyclone track forecasts. Official NHC forecasts have improved at a rate faster than 1% during the 1990s, suggesting substantial improvements to the numerical guidance. This operational ensemble since 1976 has been analyzed as a set to mark the improvements of the guidance with time. The improvements in the ability of the guidance to span the actual track of tropical cyclones, the performance of the ensemble mean with time, and changes in individual model performance are to be presented.

Alvarez Zarikian, C.A., P.L. Blackwelder, T. Hood, T.A. Nelsen, and C. Featherstone. Ostracodes as indicators of natural and anthropogenically-induced changes in coastal marine ecosystems. Proceedings, 17th International Conference of the Coastal Society: Coasts at the Millenium, Portland, Oregon, July 9-12, 2000. The Coastal Society, 896-905 (2000).

No abstract.

Atlas, D., C.W. Ulbrich, F.D. Marks, R.A. Black, E. Amitai, P.T. Willis, and C.E. Samsury. Partitioning tropical oceanic convective and stratiform rains by draft strength. Journal of Geophysical Research, 105(D2):2259-2267 (2000).

The discrimination of convective from stratiform tropical oceanic rains by conventional radar-based textural methods is problematic because of the small size and modest horizontal reflectivity gradients of the oceanic convective cells. In this work, the vertical air motion measured by an aircraft gust probe is used as a discriminator which is independent of the textural methods. A threshold draft magnitude approximately equal to 1 m s^-1 separates the two rain types. Simultaneous airborne in-situ observations of drop size distributions (DSD) made during the Tropical Ocean-Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE) were used to compute Z, R, and other integral parameters. The data were quality controlled to minimize misclassifications. The convective and stratiform rains, observed just below the melting level but adjusted to surface air density, are characterized by power law Z-R relations (Z = 129R^1.38 [convective]) and 224R^1.28 [stratiform]). However, at R < 10 mm h^-1, the convective population is essentially coincident with the small-drop size, small-Z portion of the stratiform population. Tokay and Short (1996) found a similar result when their algorithm did not separate the rain types unambiguously at R < 10 mm h^-1. The physical reasons for the wide variability of the drop size spectra and Z-R points in stratiform rain and their overlap with that of convective rain are proposed. The subtle distinctions in the microphysical properties and the Z-R relations by rain type could not be found by Yuter and Houze using the same airborne DSD data set as that in this work and a radar-based textural classification algorithm.

Beal, L.M., R.L. Molinari, T.K. Chereskin, and P.E. Robbins. Reversing bottom circulation in the Somali Basin. Geophysical Research Letters, 27(16):2565-2568 (2000).

Two sets of direct velocity measurements were taken, concurrent with hydrographic data, in the bottom waters of the northern Somali Basin in June and September 1995. The velocities indicate a temporal flow reversal in the bottom circulation, which is consistent with the changing density structure between the sections. In June, there is evidence of a southward Deep Western Boundary Current with a transport of 5 Sv. By September, flow close to the boundary is northward, with a transport of 2.6 Sv. Furthermore, the deep density gradient across the interior of the Somali Basin also changes between occupations, implying a cyclonic circulation in June and anticyclonic flow in September. Rossby wave activity is high in this region during the southwest monsoon, yet there is also evidence of a strong barotropic component to the Great Whirl in September, which may cause the reversal in the abyssal circulation.

Bentamy, A., P. Flament, Y. Quilfen, K.B. Katsaros, and H. Roquet. Analysis of ocean surface winds derived from ERS-1, ERS-2, and NSCAT measurements. CERSAT News, Issue No. 11, 2 pp. (2000).

No abstract.

Black, M.L., and J.L. Franklin. GPS dropsonde observations of the wind structure in convective and non-convective regions of the hurricane eyewall. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 448-449 (2000).

GPS dropsonde observations in the inner core regions of tropical cyclones have shown remarkable vertical variation in the wind structure. Vertical profiles from sondes released in the convective portions of the hurricane eyewall frequently exhibit multiple low to mid-level wind maxima. These maxima may contain peak winds significantly higher than those measured at typical reconnaissance altitudes (3 km). Convective mixing is thought to be a mechanism that may bring this high momentum air to altitudes at or near the sea-surface. In non-convective regions, both outside and within the eyewall, however, the wind profiles typically do not have the large low-level wind maxima and the wind speed frequently decreases rapidly toward the surface in the boundary layer. Preliminary analyses of dropsonde wind profiles have suggested systematic differences in the shape of these soundings. An important result from these analyses is that the surface wind speed is a substantially higher fraction of the wind at altitude in convective regions than in non-convective or stratiform regions. We plan on classifying several hundred dropsonde observations according to the convective environment they fall through. The classifications will be based upon simultaneous radar observations from NOAA P-3 research flights into tropical cyclones in various stages of development. Individual profiles from convective and non-convective regions of the storms will be presented to highlight some of the observed differences in wind structure. A brief statistical analyses is planned to describe the variance in the mean structure derived from these classifications. A discussion of some of the possible physical mechanisms for the difference in the observed wind profiles will be discussed.

Black, M.L., A.B. Damiano, and S.R. White. The first eyewall penetration by the NOAA G-IV aircraft. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 175-176 (2000).

On August 9, 1999, NOAA's Aircraft Operations Center (AOC) was tasked by the Tropical Prediction Center/National Hurricane Center and the Central Pacific Hurricane Center (CPHC) to deploy the NOAA Gulfstream G-IV jet aircraft and crew to Honolulu, Hawaii for synoptic surveillance missions around Hurricanes Eugene and Dora. Both of these storms had tracked westward across the eastern Pacific basin into the area of responsibility of CPHC (west of 140°W) and posed potential threats to Hawaii. After a successful G-IV mission around Hurricane Eugene on 12 August, a similar flight-track was designed to collect synoptic data from GPS dropsondes around Hurricane Dora on 14 August. At the time, Dora was steadily weakening from a peak intensity of 120 kts on 13 August with maximum sustained surface winds forecast to be 70 kts during the mission. Dora was a compact hurricane with a circular, well-defined eye and had only a couple of weak rainbands outside of the central dense overcast. A deviation from the proposed flight track was planned to fly the G-IV on a heading towards the eye during the closest approach to Hurricane Dora. The maneuver's purpose was to observe the structure of a hurricane at altitudes >40,000 feet with the aircraft's nose radar system. During the flight, the G-IV crew observed that Hurricane Dora was closer to the flight track than was forecast, so that when the aircraft turned toward the south side of the storm, the eyewall was approximately 80 nmi away. After a brief discussion of the structure of Dora and safety considerations, the flight director and aircraft commander decided to fly into the eye before heading back to the original track. This represented the first time that the G-IV would penetrate the eyewall of a hurricane, and would do so at an altitude of 45,000 feet (~145 mb). The aircraft flew through a thick cirrus cloud cover in the eyewall and that thinned while in the eye. Two GPS dropsondes were released while in (above) the eye of Hurricane Dora, and a third sonde was dropped just outside of the southwest eyewall while the G-IV was exiting the storm. Both of the eye drops drifted near or into the eyewall as they descended and one of them showed winds in excess of 80 kts at altitudes below 3000 ft. During the penetration, wind speeds at a flight level of 45,000 feet were approximately 5 kts and the wind direction showed anticyclonic flow.

Black, P.G., E.W. Uhlhorn, M.D. Powell, and J. Carswell. A new era in hurricane reconnaissance: Real-time measurement of surface wind structure and intensity via microwave remote sensing. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 199-200 (2000).

No abstract.

Black, P.G., E.W. Uhlhorn, J.J. Cione, G.J. Goni, L.K. Shay, S.D. Jacob, E.J. Walsh, and E.A. D'Asaro. Hurricane intensity change modulated by air-sea interaction effects based on unique airborne measurements during the 1998-1999 hurricane seasons. Proceedings, 10th Conference on Interaction of the Sea and Atmosphere, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, J7-J8 (2000).

No abstract.

Boebel, O., S. Anderson-Fontana, C. Schmid, I. Ansorge, P. Lazarevich, J.R.E. Lutjeharms, M. Prater, T. Rossby, and W. Zenk. KAPEX RAFOS float data report, 1997-1999. Part A: The Agulhas and South Atlantic Current components. GSO Technical Report 2000-2, UCT Oceanography Report 2000-1, 194 pp. (2000).

No abstract.

Bosart, L.F., W.E. Bracken, J. Molinari, C.S. Velden, and P.G. Black. Environmental influences on the rapid intensification of Hurricane Opal (1995) over the Gulf of Mexico. Monthly Weather Review, 128(2):322-352 (2000).

Hurricane Opal intensified rapidly and unexpectedly over the Gulf of Mexico between 1800 UTC 3 October 1995 and 1000 UTC 4 October 1995. During this period, the storm central pressure decreased from 963 to 916 hPa and sustained winds reached 68 m s-1. Analyses that include high-resolution GOES-8 water vapor winds and European Centre for Medium-Range Weather Forecasts (ECMWF) and National Centers for Environmental Prediction (NCEP) gridded datasets are employed to examine the rapid intensification phase of Opal. Opal first reached tropical storm strength on 29V30 September 1995 as it interacted with a trough while situated over the Yucatan Peninsula. Opal deepened moderately (20 hPa) in the 24 h ending 1200 UTC 2 October as it achieved minimal hurricane strength and as it turned northeastward. The deepening occurred in conjunction with an environmental flow interaction as determined by an Eliassen balanced vortex outflow calculation. As Opal accelerated toward the Gulf coast by 1200 UTC 3 October, it approached the equatorward jet-entrance region of a progressive synoptic-scale trough. The trough tail extended southwestward toward the lower Texas coast. As the poleward portion of the trough moved eastward, the equatorward end of the trough lagged behind, stretched meridionally, and partially fractured as it encountered a deformation region over the northwest Gulf. Enhanced outflow and increased divergence in the upper troposphere poleward of Opal was associated with the deformation zone and the partially fractured trough tail. An analysis of the 300-200-hPa layer-averaged divergence and 6-h divergence change based on an analysis of the water vapor winds shows a significant increase in the magnitude and equatorward extension of the divergence core toward Opal that begins at 1200 UTC 3 October and is most apparent by 1800 UTC 3 October and 0000 UTC 4 October. This divergence increase is shown to precede convective growth in the eyewall and the onset of rapid intensification and is attributed to a jet-trough-hurricane interaction in a low-shear environment. Calculations of balanced vortex outflow based on the ECMWF and NCEP gridded datasets confirms this interpretation. A crucial finding of this work is that the jet-trough-hurricane interaction and explosive intensification of Opal begins near 0000 UTC 4 October when the storm is far from its maximum potential intensity (MPI), and the 850-200-hPa shear within 500 km of the center is weak (2-3 m s^-1). In this first stage of rapid intensification, the winds increase by almost 15 m s^-1 to 52 m s^-1 prior to the storm reaching an oceanic warm-core eddy. The second stage of rapid intensification occurs between 0600 and 1000 UTC 4 October when Opal is over the warm-core eddy and sustained winds increase to 68 m s^-1. During this second stage, conditions are still favorable for a jet-trough-hurricane interaction as demonstrated by the balanced vortex outflow calculation. Opal weakens rapidly after 1200 UTC 4 October when the storm is near its MPI, the shear is increasing, and the eye is leaving the warm-core eddy. This weakening occurs as Opal moves closer to the trough. It is suggested that an important factor in determining whether a storm-trough interaction is favorable or unfavorable for intensification is how far a storm is from its MPI. The results suggest that a favorable storm-trough interaction ("good trough") can occur when a storm is far from its MPI. It is suggested that although the ECMWF (and to lesser extent NCEP) analyses reveal the trough-jet-hurricane interaction through the balanced vortex outflow calculation, that the failure of the same models to predict the rapid intensification of Opal can be attributed to the inability of the model to resolve the eye and internal storm structure and the associated influence of the trough-jet-hurricane interaction on the diabatically driven storm secondary circulation. The analyses also indicate that the high spatial and temporal resolution of the GOES-8 water vapor winds reveal important mesoscale details of the trough-jet-hurricane interaction that would otherwise be hidden.

Cione, J.J., P.G. Black, and S.H. Houston. Surface observations in the hurricane environment. Monthly Weather Review, 128(5):1550-1561 (2000).

Composite analyses of marine surface observations from 37 hurricanes between 1975 and 1998 show that the difference between the sea surface temperature and the surface air temperature significantly increases just outside the hurricane inner core. This increase in the sea-air contrast is primarily due to a reduction in surface air temperature and is more likely to occur when sea temperatures are at least 27°C. Results show that 90% of the observed cooling occurs 3.25°-1.25° latitude from the hurricane center, well outside the region of strongest surface winds. Since surface pressure only decreases 3 mb over this interval, the 2°C drop in air temperature is not a result of adiabatic expansion. For the subset of observations that contained moisture measurements, surface specific humidity decreased 1.2 g kg^-1 4.5°-1.75° latitude from the storm center. This finding suggests that the observed reduction in surface air temperature is not simply a result of near-surface evaporation from sea spray or precipitation. An alternate explanation may be that outside the hurricane inner core, unsaturated convective downdrafts act to dry and evaporatively cool the near-surface environment. Between 3.25° and 1.25° radius, composite analyses show that low-level inflow is not isothermal, surface moisture is not constant, and the near-surface environment is not in thermodynamic equilibrium with the sea. Calculations based on these observations show that theta_e decreases between 4.0° and 1.25° radius and then quickly rises near the inner core as surface pressures fall and specific humidity increases. Surface fluxes of heat and moisture are also observed to significantly increase near the inner core. The largest increase in surface sensible heat flux occurs radially inward of 1.5°, where surface winds are strong and sea-air temperature contrasts are greatest. As a result, the average Bowen ratio is 0.20°-0.5° radius from the composite storm center. This increase in sensible heat flux (in conjunction with near-saturated conditions at low to midlevels) may help explain why average surface air temperatures inside 1.25° radius remain relatively constant, despite the potential for additional cooling from evaporation and adiabatic expansion within the high wind inner core.

Cione, J.J., E.W. Uhlhorn, and P.G. Black. Atmospheric boundary layer and upper ocean structure observed in Hurricane Erika (1997). Proceedings, 10th Conference on Interaction of the Sea and Atmosphere, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, J70-J71 (2000).

No abstract.

Cione, J.J., P. Molina, J. Kaplan, and P.G. Black. SST time series directly under tropical cyclones: Observations and implications. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 1-2 (2000).

No abstract.

Cook, T.M., L.K. Shay, P.G. Black, G.J. Goni, M.M. Huber, S.D. Jacob, and J.J. Cione. Coupled air-sea interactions during Hurricane Bonnie. Proceedings, 10th Conference on Interaction of the Sea and Atmosphere, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, J68-J69 (2000).

No abstract.

Cushman-Roisin, B., O.E. Esenkov, and B.J. Mathias. A particle-in-cell-method for the solution of two-layer shallow-water equations. International Journal of Numerical Methods in Fluids, 32(5):515-543 (2000).

A particle-in-cell (PIC) numerical method developed for the study of shallow-water dynamics, when the moving fluid layer is laterally confined by the intersection of its top and bottom surfaces, is described. The effect of ambient rotation is included for application to geophysical fluids, particularly open-ocean buoyant vortices in which the underlying density interface outcrops to the surface around the rim of the vortex. Extensions to include the dynamical effect of a second moving layer (baroclinicity) and the presence of a lateral rigid boundary (sidewall) are also described. Although the method was developed for oceanographic investigations, applications to other fluid mechanics problems would be straightforward.

D'Asaro, E.A., and P.G. Black. Turbulence in the ocean boundary layer below Hurricane Dennis. Proceedings, 10th Conference on Interaction of the Sea and Atmosphere, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, J62-J63 (2000).

No abstract.

Dodge, P.P., S.M. Spratt, F.D. Marks, D.W. Sharp, and J.F. Gamache. Dual-Doppler analyses of mesovortices in a hurricane rainband. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 302-303 (2000).

The U.S. Weather Research Program identified landfalling tropical cyclones as a major focus for research in the coming years. In 1998, the Hurricane Research Division (HRD) of NOAA's Atlantic Oceanographic and Meteorological Laboratory coordinated experiments with other agencies and university groups in Hurricanes Bonnie, Earl, and Georges. On these flights, airborne Doppler radar data were collected to combine with WSR-88D radar data in three-dimensional analyses to document evolution of tropical cyclones as they make landfall, and to provide data for testing WSR-88D tropical cyclone algorithms. Hurricane Bonnie made landfall in near Wilmington, North Carolina as a Category 2 hurricane on 26 August. There were two HRD missions near the time of landfall. The first flight concentrated on examining the structure of the spiral rainbands and the second flight surveyed the hurricane as it interacted with the coast. During the flights, there was a vigourous rainband ~180 km northeast of the center with several mesocyclones (as identified on the Morehead City WSR-88D) that later produced confirmed tornadoes on land. Both NOAA aircraft had to deviate around strong cells in this band, between 1540 and 1830 UTC, and those deviations resulted in small Doppler analysis boxes enclosing some of the mesocyclones. A companion paper (Spratt et al.) uses dropsondes and adjacent radiosondes to describe the local environment in which the Bonnie mesocylones were embedded, and in this paper we will present windfield analyses, from combining WSR-88D and airborne Doppler radar data, that provide the three dimensional structure of the mesocyclones. The Doppler data are too coarse to resolve actual tornadoes, but the parent mesoscale circulations are clearly resolved.

Dunion, J.P., S.H. Houston, M.D. Powell, C.S. Velden, and P.G. Black. Using surface adjusted GOES low-level cloud-drift winds to improve the estimation of tropical cyclone outer wind radii. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 488-489 (2000).

No abstract.

Enfield, D.B., and A.M. Mestas-Nunez. Global modes of ENSO and non-ENSO SST variability and their associations with climate. In: El Niño and the Southern Oscillation: Multiscale Variability and Global and Regional Impacts, H.F. Diaz and V. Markgraf (eds.). Cambridge University Press (ISBN 0521621380), 89-112 (2000).

In this chapter we review much of the recent work by others regarding the nature of the global modes of sea surface temperature (SST) variability and the SST involvement in interannual to multidecadal climate variability. We also perform our own analysis of global SST so as to describe and separate the SST variability associated with El Niño-Southern Oscillation (ENSO) from the low-frequency modes not associated with ENSO (non-ENSO). ENSO is a global phenomenon with significant phase propagation between basins, which we preserve and describe using complex empirical orthogonal function (CEOF) analysis, and subsequently remove from the global SST data. A second CEOF analysis of the residuals reveals three non-ENSO modes of low-frequency variability that are identified with and related to signals described in the reviewed literature: (1) a secular trend representing the global warming signal with associated superimposed decadal variability; (2) an interdecadal mode with maximal realization in the extratropical North Pacific; and (3) a multidecadal mode with maximal realization in the extratropical North Atlantic. Regression- and SVD-based analyses of the relationships between the SST data and a high-quality precipitation data set demonstrate for the interannual-to-decadal time scales of the western hemisphere tropics that (a) tropical Atlantic SSTA is comparable to the Pacific ENSO in its relevance to regional rainfall and is not redundant with respect to ENSO; and (b) non-ENSO variability explains a significant fraction of the total covariance between the two variables. We are led to conclude that present operational climate predictions can be significantly improved by extending numerical SST predictions from the Pacific to the world ocean and by enabling these models to emulate the observed non-ENSO modes of global variability.

Enfield, D.B., and A.M. Mestas-Nunez. Interannual to multidecadal climate variability and its relationship to global sea surface temperatures. In Interhemispheric Climate Linkages, V. Markgraf (ed.). Academic Press (ISBN 0124726704), 17-29 (2000).

As a benchmark to help profile paleoclimates across the Americas we develop an overview of what is known of modern climate variability on a planetary scale, with emphasis on climate manifestations in the Western Hemisphere. From instrumental observations taken as early as the mid-19th century, we look at both atmospheric and oceanic variables and consider their relationships on timescales ranging from interannual to multidecadal. We focus on three of the most important climate modes: the interannual El Niño-Southern Oscillation (ENSO), the interdecadal Pacific Decadal Oscillation (PDO), and the multidecadal North Atlantic Oscillation (NAO). The variable of greatest interest is sea surface temperature (SST) because it is arguably the least understood of the atmospheric boundary conditions for prehistoric climates and yet one of the most critical for effecting atmospheric model simulations of those climates. The analysis begins by computing a global distribution of the trend in SST, which turns out to be highly non-uniform, with characteristics that may reflect low-frequency changes in shallow water mass formation. We then compute a global, canonical mode for ENSO that preserves the amplitude and phase structures of interannual ENSO variability worldwide. The ranking of the modal amplitudes of ENSO events differs from the absolute amplitudes obtained by indexing SST data directly. This reflects the importance of the (non-ENSO) decadal-multidecadal climate modes in modifying the intensity of ENSO-related ocean warmings. Comparing the global mode between the ends of the 19th and 20th centuries, we see essentially no difference in amplitudes and frequency of ENSO on the global warming timescale, although such changes have occurred on shorter, multidecadal timescales. Upon removal of the global ENSO mode from the data, the residual variability is subjected to two different analyses that extract very similar spatio-temporal patterns of SST for the PDO- and NAO-like climate modes. The climate variations with longer timescales (PDO, NAO) together account for about the same amount of variance as ENSO, globally, and in some regions, e.g., the northeastern North Pacific, may rival ENSO in their climate and marine impacts. The NAO, in particular, involves an Atlantic-Pacific connection that may arise through fluctuations in the polar vortex, an aspect which may also characterize previous climates. In our discussion, we speculate on what might be learned from the instrumental record regarding possible characteristics of ancient climates, especially regarding the possibility that ENSO may have been considerably different or even absent in the mid-Holocene.

Enfield, D.B., and A.M. Mestas-Nunez. Tropospheric direct circulations associated with the climatic components of SST variability in the equatorial Pacific. Proceedings, 10th Conference on Interaction of the Sea and Atmosphere, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, J49-J50 (2000).

No abstract.

Esenkov, O.E. A numerical study of the dynamics of the Somali Current system. Ph.D. thesis, University of Miami, Rosenstiel School of Marine and Atmospheric Science, 140 pp. (2000).

The evolution of surface circulation, salinity budget, and processes at intermediate depth in the northwestern Indian Ocean were studied with the open boundary version of the Miami Isopycnic Coordinate Ocean Model (MICOM). Under climatological wind and thermodynamic forcing, the model develops solutions that are in good agreement with global MICOM results and with observations. When the observed winds (Legler et al., 1989) force the model, interannual variability of the surface fields increases significantly. However, coalescence of the two large eddies in the end of the summer monsoon, which was observed in some years, does not occur in the model. To identify what processes facilitate the merger, a series of experiments was performed with modified model parameters and forcing fields. The eddies coalesced when half-slip, rather than no-slip, boundary conditions were used. In this case, less positive vorticity was produced at the coast, resulting in a reduced blocking effect on the propagation of the southern eddy. Socotra Island, which is submerged in the standard model, hinders movement of the northern anticyclone, leading to stronger interaction between the eddies and their subsequent merging. A more realistic coalescence occurs in an experiment where winds are held constant after reaching the peak summer value. Freshwater fluxes from the east and south were previously considered important for the salinity budget in the Arabian Sea, where evaporation exceeds precipitation; however, the model demonstrated that only cross-equatorial transport of low-salinity water in the upper 400 m is essential. About 86% of this water is advected below the surface layer at the western boundary. The strongest interaction between the mixed layer and the oceanic interior occurs during the summer in the coastal upwelling regions off Somalia. Forty-three percent of all upwelled water comes from depths between 100 m and 200 m, thus signifying the importance of mid-depth circulation and water mass distribution for the surface processes. Both observations and model solutions demonstrate strong annual cycle and alongshore variability of coastal subsurface circulation. A cross-equatorial northward flow below the surface, which exists throughout the year, is disconnected from currents farther north. A southward undercurrent north of 5°N is present during the winter monsoon. Water for the current is supplied by flows from the north and northeast. The former originates in the Persian Gulf and carries higher-salinity water, while the latter contribution is mainly from the Gulf of Aden. Separation of the southward undercurrent near 4°N is not caused by its interaction with a topographical ridge, as was previously suggested. Agreement with the observations north of 5°N improves when Socotra Island is present in the model.

Feuer, S.E., M.L. Black, and J.L. Franklin. The asymmetric wind structure of tropical cyclones in various shear environments. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 450-451 (2000).

No abstract.

Ffield, A., K. Vranes, A.L. Gordon, R.D. Susanto, and S.L. Garzoli. Temperature variability within the Makassar Strait. Geophysical Research Letters, 27(2):237-240 (2000).

Recent mooring observations of ocean temperature provide the first high-resolution, long-term record of temperature variability in the Makassar Strait of the Indonesian Seas. The mooring observation span the entire cycle of the strong 1997/1998 El Ni�o. A high correlation (r = 0.67) is found between variability in the average thermocline temperature, to variability in the southward Makassar volume transport: during high (low) volume transport, the average temperature of the thermocline is also high (low). In addition, from nearly 15 years of XBT data, the Makassar thermocline temperature is shown to be highly correlated (r = 0.77) to SOI. This reveals that the Makassar temperature field, when coupled with the throughflow, transmits the equatorial Pacific El Ni�o and La Ni�a temperature fluctuations into the Indian Ocean. The ENSO variability in the internal energy transport is calculated: 0.63 PW during the La Ni�a months of December 1996 through February 1997, and 0.39 PW during the El Ni�o months of December 1997 through February 1998.

Fleurant, C.I., W.D. Wilson, W. Johns, S.L. Garzoli, R.H. Smith, D. Fratantoni, P. Richardson, and G.J. Goni. CTD/O₂, LADCP, and XBT measurements collected aboard the R/V Seward Johnson, February-March 1999: North Brazil Current Rings Experiment, cruise 2 (NBC-2). NOAA Data Report, OAR AOML-37 (PB2001-100485), 298 pp. (2000).

Summaries of conductivity-temperature-depth (CTD/O₂), lowered acoustic Doppler current profiler (LADCP), and expendable bathythermograph (XBT) measurements and hydrographic data acquired on an oceanographic research cruise during the winter of 1999 aboard the Harbor Branch Oceanographic Institution ship R/V Seward Johnson are presented. Data acquisition and processing systems are described, and calibration procedures are documented. Station location, CTD/O₂, LADCP, XBT summary data listings, and profiles are included for each station.

Fleurant, C.I., W.D. Wilson, W. Johns, S.L. Garzoli, R.H. Smith, D. Fratantoni, P. Richardson, and G.J. Goni. CTD/O₂, LADCP, and XBT measurements collected aboard the R/V Seward Johnson, February-March 2000: North Brazil Current Rings Experiment, cruise 3 (NBC-3). NOAA Data Report, OAR AOML-38 (PB2001-100486), 258 pp. (2000).

Summaries of conductivity-temperature-depth (CTD)/O₂, lowered acoustic Doppler current profiler (LADCP) measurements, and hydrographic data acquired on an oceanographic research cruise during the winter of 2000 aboard the Harbor Branch Oceanographic Institution ship R/V Seward Johnson are presented. Data acquisition and processing systems are described, and calibration procedures are documented. Station location, CTD/O₂, LADCP summary data listings, and profiles are included for each station.

Fleurant, C.I., W.D. Wilson, W. Johns, S.L. Garzoli, R.H. Smith, D. Fratantoni, P. Richardson, and G.J. Goni. CTD/O₂, LADCP, and XBT measurements collected aboard the R/V Seward Johnson, November-December 1998: North Brazil Current Rings Experiment, cruise 1 (NBC-1). NOAA Data Report, OAR AOML-39 (PB2001-101653), 276 pp. (2000).

Summaries of conductivity-temperature-depth (CTD/O₂), lowered acoustic Doppler current profiler (LADCP), expendable bathythermograph (XBT) measurements, and hydrographic data acquired on an oceanographic research cruise during the fall of 1998 aboard the Harbor Branch Oceanographic Institution ship R/V Seaward Johnson are presented. Data acquisition and processing systems are described, and calibration procedures are documented. Station location, CTD/O₂, LADCP, XBT summary data listings, and profiles are included for each station.

Franklin, J.L., M.L. Black, and K. Valde. Eyewall wind profiles in hurricanes determined by GPS dropwindsondes. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 446-447 (2000).

No abstract.

Gamache, J.F., M.L. Black, and H.E. Willoughby. Radial variation of azimuthally averaged flow across the hurricane core as observed with airborne Doppler radar. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 416-417 (2000).

No abstract.

Garzoli, S.L., and G.J. Goni. Combining altimeter observations and oceanographic data for ocean circulation and climate studies. In Satellites, Oceanography, and Society, D. Halpern (ed.). Elsevier Oceanographic Series (ISBN 0444505016), 63, 79-95 (2000).

Calibrating Topography Experiment (TOPEX)/Poseidon (T/P) altimeter data to inverted echo sounder measurements is one of the methodologies developed to advance the study of the South Atlantic Ocean. The mass transport of the main boundary currents can be monitored using dynamic height time series obtained from altimeter-derived sea surface height anomalies. A two-layer model yields upper-layer thickness and surface dynamic height of the ocean in areas of strong vertical stratification to identify and track anticyclonic rings, such as those shed from the Agulhas retroflection, which play an important role in the interocean exchange of heat and mass. Interannual variability of boundary currents, derived from analysis of the first five years of T/P data, is discussed. A combination of T/P data and in-situ observations provides significant contributions to the study of ocean dynamics for climate applications.

Godin, O.A., D. Yu Mikhin, and D.R. Palmer. Monitoring of ocean currents in the coastal zone. Izvestiya Atmospheric and Oceanic Physics, 36(1):131-142 (2000).

A method proposed recently for remote monitoring of currents in coastal regions of the ocean is discussed and compared to alternative approaches. The new method, which is referred to as the method of matched nonreciprocity (MMN), represents further development of conventional acoustic tomography of currents as applied to shallow-sea conditions. In measurements of currents, low-frequency acoustic waves are employed as sounding signals. The MMN makes it possible to obtain real-time current charts in a region extending horizontally to tens or hundreds of kilometers and covering the whole depth of the water from the surface of the ocean to its bottom. Such charts are important in solving major scientific problems, in particular, monitoring of climate changes and verification of global-circulation models. It is shown that the MMN is free of limitations inherent in the monitoring methods proposed previously. The MMN is based on recent advances in the theory and mathematical modeling of acoustic propagation in inhomogeneous moving media and also in the use of the matched-field method for solving tomographic inverse problems. The physical basis of the MMN is a choice of an acoustic-field characteristic for measurements, which must be sensitive to current profiles and insensitive to both acoustic-speed variations and bottom topography. As a result, the MMN leads to a stable solution of the inverse problem for the vertical distribution of current velocity. The development of methods for current acoustic tomography is considered from the standpoint of their applicability to monitoring ocean dynamics in coastal regions. Possible applications of the MMN to solving other oceanographic problems are also discussed.

Goldenberg, S.B. Intraseasonal predictability of Atlantic basin hurricane activity. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 59-60 (2000).

No abstract.

Goldenberg, S.B., C.W. Landsea, and G.D. Bell. Summary of the 1999 Atlantic hurricane season: A climatic perspective. Proceedings, 24th Annual Climate Diagnostics and Prediction Workshop, Tucson, AZ, November 1-5, 1999. National Weather Service, 1-4 (2000).

No abstract.

Goni, G.J., L.K. Shay, P.G. Black, S.D. Jacob, T.M. Cook, J.J. Cione, and E.W. Uhlhorn. Role of the upper ocean structure on the intensification of Hurricane Bret from satellite altimetry. Proceedings, 10th Conference on Interaction of the Sea and Atmosphere, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, J5-J6 (2000).

No abstract.

Hendee, J.C. A data-driven soft real-time expert system for producing coral bleaching alerts. Ph.D. thesis, Nova Southeastern University, 131 pp. (2000).

In the Florida Keys there are many physical, chemical, and biological events of interest and concern to personnel of the Florida Keys National Marine Sanctuary, marine biologists, oceanographers, fishermen, and divers. Large volumes of continuously-generated meteorological and oceanographic data from instruments in the SEAKEYS (Sustained Ecological Research Related to Management of the Florida Keys Seascape) network help to understand these events. However, since no one has the time to look at every printout of data from every station, every day, seven days a week, it is highly desirable to have an automated system that can monitor parameters of interest and produce specialized alerts of specific events, as indicated by prescribed or abnormal ranges, or combinations of parameters. A soft real-time expert system was developed to produce such alerts based on data input from the SEAKEYS network. The prototype system collected data from the Sombrero Reef station in the network and produced automated e-mail and World-Wide Web alerts when conditions were thought to be conducive to, or predictive of, coral bleaching, which occurs under environmental conditions stressful to corals. Configuration of the system included a point system for three coral bleaching models (high sea temperature only, high sea temperature plus low winds, high sea temperature plus low winds plus low tide). The approach is an important development in the use of knowledge-based systems to solve environmental problems, as it provides for knowledge synthesis (in the form of data summaries) from any environmental ASCII data stream or table, be it real-time or not.

Hendee, J.C. An environmental information synthesizer for expert systems: A framework for use in near real-time detection of harmful algal blooms. Proceedings, 17th International Conference of The Coastal Society: Coasts at the Millennium, Portland, OR, July 9-12, 2000. The Coastal Society, 233-241 (2000).

As an enhancement to the SEAKEYS environmental monitoring network in the Florida Keys National Marine Sanctuary, software called the Environmental Information Synthesizer for Expert Systems (EISES) has been utilized together with a specially developed expert system to model and report the near real-time sensing of environmental conditions conducive to the onset of a harmful algal bloom (HAB, e.g., "red tide"). Actual near real-time in-situ fluorometry data was matched with wind speeds and photosynthetically active radiation at the Long Key SEAKEYS station in Florida Bay to simulate the onset of an HAB. These incidences were e-mailed to the knowledge engineer as they occurred, and could in the future be e-mailed to regulatory agencies, or posted to a Web site, as is done with a similarly developed expert system for coral bleaching. This approach shows promise with the future remote detection of HAB pigment data via in-situ or satellite sensors.

Hood, T., C.A. Alvarez Zarikian, P.L. Blackwelder, T.A. Nelsen, and C. Featherstone. Identifying multiple stressors in the coastal ocean: The role of microfauna in discriminating between natural and anthropogenic influences. Proceedings, 17th International Conference of the Coastal Society: Coasts at the Millenium, Portland, Oregon, July 9-12, 2000. The Coastal Society, 697-704 (2000).

No abstract.

Jacob, S.D., L.K. Shay, P.G. Black, and S.H. Houston. Upper ocean response to hurricane wind asymmetries. Proceedings, 10th Conference on Interaction of the Sea and Atmosphere, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, J66-J67 (2000).

No abstract.

Jacobs, S.D., L.K. Shay, A.J. Mariano, and P.G. Black. The 3D oceanic mixed layer response to Hurricane Gilbert. Journal of Physical Oceanography, 30(6):1407-1429 (2000).

Upper-ocean heat and mass budgets are examined from three snapshots of data acquired during and after the passage of Hurricane Gilbert in the western Gulf of Mexico. Measurements prior to storm passage indicated a warm core eddy in the region with velocities of O(1) m s^-1. Based upon conservation of heat and mass, the three-dimensional mixed layer processes are quantified from the data. During and subsequent to hurricane passage, horizontal advection due to geostrophic velocities is significant in the eddy regime, suggesting that prestorm oceanic variability is important when background flows have the same magnitude as the mixed layer current response. Storm-induced near-inertial currents lead to large vertical advection magnitudes as they diverge from and converge toward the storm track. Surface fluxes, estimated by reducing flight-level winds to 10 m, indicate a maximum wind stress of 4.2 N m^-2 and a heat flux of 1200 W m^-2 in the directly forced region. The upward heat flux after the passage of the storm has a maximum of 200 W m^-2 corresponding to a less than 7 m s^-1 wind speed. Entrainment mixing across the mixed layer base is estimated using three bulk entrainment closure schemes that differ in their physical basis of parameterization. Entrainment remains the dominant mechanism in controlling the heat and mass budgets irrespective of the scheme. Depending on the magnitudes of friction velocity, surface fluxes and/or shear across the mixed layer base, the pattern and location of maximum entrainment rates differ in the directly forced region. While the general area of maximum entrainment is in the right-rear quadrant of the storm, the shear-induced entrainment scheme predicts a narrow region of cooling compared to the stress-induced mixing scheme and observed SST decreases. After storm passage, the maximum contribution to the mixed layer dynamics is associated with shear-induced entrainment mixing forced by near-inertial motions up to the third day as indicated by bulk Richardson numbers that remained below criticality. Thus, entrainment based on a combination of surface fluxes, friction velocity, and shear across the entrainment zone may be more relevant for three-dimensional ocean response studies.

Jones, R.W., and H.E. Willoughby. Linear motion of a two-layer baroclinic hurricane in shear. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 83-84 (2000).

No abstract.

Kang, W.-J., J.H. Trefy, T.A. Nelsen, H.R. Wanless. Direct atmospheric inputs versus runoff fluxes of mercury to the lower Everglades and Florida Bay. Environmental Science and Technology, 34(19):4058-4063 (2000).

Age-dated sediments from the lower Everglades and Florida Bay provide a record of inputs of excess Hg from direct atmospheric input versus runoff. Direct atmospheric fluxes of excess Hg to sediments in the lower Everglades and Florida Bay, calculated using a mass balance model for excess ²¹⁰Pb, currently average 24 ± 9 µg m^-2 yr^-1 and are comparable with recent results from bulk atmospheric deposition. In contrast, present-day runoff fluxes of excess Hg to area sediments are variable, ranging from about 4-160 µg m^-2 yr^-1. The runoff flux now carries 60-80% of the total flux of excess Hg to the sediments in areas near river sloughs but less than 20% of the total flux of excess Hg in more remote areas of Florida Bay. These results show the greater importance of runoff relative to direct atmospheric deposition for Hg inputs to many areas of the lower Everglades and immediately adjacent Florida Bay. Thus, the choice of future water management strategies can play an important role in controlling Hg inputs to the lower Everglades and portions of Florida Bay.

Kaplan, J., and M. DeMaria. Large-scale characteristics of rapidly intensifying tropical cyclones in the North Atlantic basin. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 232-233 (2000).

No abstract.

Katsaros, K.B. The paradigm for research on atmosphere-ocean interaction at the cusp between the 20th and 21st centuries. Bulletin of the American Meteorological Society, 81(4):837-838 (2000).

No abstract.

Katsaros, K.B., and R.T. Pinker. Algorithm improvement for novel applications in earth science research. Proceedings, First Meteosat Second Generation Research Announcement of Opportunity Workshop, Bologna, Italy, May 17-19, 2000. European Space Agency, ESA SP-452, 103-106 (2000).

No abstract.

Katsaros, K.B., P. Vachon, P.G. Black, P.P. Dodge, and E.W. Uhlhorn. Wind fields from SAR: Could they improve our understanding of storm dynamics? John Hopkins APL Technical Digest, 21(1):86-93 (2000).

Four hurricane images obtained by RADARSAT are examined for what they reveal about the storms. Features seen include strong variations in backscatter from the surface in and around convective cells associated with rain cells and rainbands, coupled with increased backscatter in regions of high wind outflow. Long linear features of scale 3-6 km are observed in three of the four hurricanes, probably from secondary circulations in the atmospheric boundary layer (roll vortices). They occur between convective rainbands, where the descending motion could produce a well-defined boundary layer. Although the origins of and the mechanisms producing the features are still not clear, the high resolution, wide-swath coverage modes of synthetic aperture radar provide new observations and present important questions for further research.

Kelly, P.S., K.M.M. Lwiza, R.K. Cowen, and G.J. Goni. Low-salinity pools at Barbados, West Indies: Their origin, frequency, and variability. Journal of Geophysical Research, 105(C8):19,699-19,708 (2000).

A vertical array of conductivity-temperature sensors moored off the west coast of Barbados, West Indies, from May 1996 to November 1997 revealed a heterogeneous and variable salinity pattern punctuated by six intrusions of low-salinity water (<34.5 psu) into the region. A typical intrusion extended to 30 m depth and lasted ~25 days, although one intrusion extended to 47 m and lasted 94 days. Water samples taken during an intrusion in May 1997 have Radium 228/226 activity ratios of approximately 1, consistent with previous measurements in Barbados of water that originated in the Amazon River mixing zone. The Amazon water likely was translated to Barbados in rings spawned from the North Brazil Current. Analysis of sea height anomaly derived from the TOPEX/Poseidon satellite supports this conclusion and reveals that, contrary to previous studies, rings are shed throughout the year, mostly during spring. The intrusions of low-salinity water and their associated velocities dramatically changed the already variable flow in our study area. We believe the complex salinity and flow we observed represented the disorganized remnants of rings that were at or near the ends of their lives. The changes we observed in the velocity and water structure are interesting in their own right as evidence of the Barbados region as a mixing zone and for their influence on recruitment of larval fishes to the reef along the island's west coast.

King, D.B., J.H. Butler, S.A. Montzka, S.A. Yvon-Lewis, and J.W. Elkins. Implications of methyl bromide supersaturations in the temperate North Atlantic Ocean. Journal of Geophysical Research, 105(D15):19,763-19,769 (2000).

Methyl bromide saturation anomalies measured in the springtime North Atlantic and summertime North Pacific Oceans during 1998 revealed persistent supersaturations in the temperate waters of the northeastern Atlantic but undersaturtions in tropical waters of both oceans. A comparison of data from this study with those from a previous cruise to the northeastern Atlantic suggests that methyl bromide is cycled seasonally in these waters and perhaps in all temperate open-ocean waters. This means that the calculated net flux of methyl bromide into the oceans is slightly less negative than previously reported. With these new insights we estimate that the global air-sea flux of methyl bromide ranges from -11 to -20 Gg yr^-1. Data combined from this and three previous cruises support a flux dependence upon sea surface temperature, as reported recently by Groszko and Moore (1998). Whereas sea surface temperature can account for 40-70% of the observed variability in methyl bromide globally, it is able to reproduce only a small fraction of the observed seasonal cycle in the temperate northeastern Atlantic. The development of reliable predictions of air-sea fluxes of methyl bromide will require information on additional variables as well.

King, D.B., J.H. Butler, S.A. Montzka, S.A. Yvon-Lewis, and J.W. Elkins. Correction to "Implications of methyl bromide supersaturations in the temperate North Atlantic Ocean." Journal of Geophysical Research, 105(D20):24,713-24,714 (2000).

No abstract.

Knaff, J.A., and Landsea, C.W. Application of the El Ni�o-Southern Oscillation CLImatology and PERsistence (CLIPER) forecasting scheme. Experimental Long-Lead Forecast Bulletin, 9(3):48-50 (2000).

No abstract.

Landsea, C.W. Climate variability of tropical cyclones: Past, present, and future. In Storms (Volume 1), R.A. Pielke, Sr. and R.A. Pielke, Jr. (eds.). Routledge, New York (ISBN 041517239X), 220-241 (2000).

No abstract.

Landsea, C.W. El Ni�o-Southern Oscillation and the seasonal predictability of tropical cyclones. In El Ni�o and the Southern Oscillation: Multiscale Variability and Global and Regional Impacts, H.F. Diaz and V. Markgraf (eds). Cambridge University Press (ISBN 0521621380), 149-181 (2000).

Perhaps the most dramatic effect that El Ni�o has upon the climate system is in changing tropical cyclone characteristics around the world. This chapter reviews how tropical cyclone frequency, intensity, and areas of occurrence are altered in all of the cyclone basins by the phases of El Ni�o-Southern Oscillation (ENSO). In addition to ENSO, other global (such as the stratospheric Quasi-Biennial Oscillation) and local factors (such as sea surface temperature, monsoon intensity and rainfall, sea level pressures, and tropospheric vertical shear) can also help modulate tropical cyclone ariability. Understanding how these various factors relate to tropical cyclone activity can be challenging due to the fairly short (on the scale of only tens of years) record of reliable data. Despite this limitation, many of the factors that have been linked to tropical cyclones, the foremost of which being ENSO, have substantial lead relationships and can be utilized to provide seasonal forecasts of tropical cyclones. Details of methodologies that have been developed for the North Atlantic, northwest Pacific, south Pacific and Australian basin tropical cyclones are presented, as well as the real-time forecasting performance of Atlantic hurricanes as issued by Professor William Gray.

Landsea, C.W., and J.A. Knaff. Application of the El Niño-Southern Oscillation CLImatology and PERsistence (CLIPER) forecasting scheme. Experimental Long-Lead Forecast Bulletin, 9(1):32-34 (2000).

No abstract.

Landsea, C.W., and J.A. Knaff. Application of the El Niño-Southern Oscillation CLImatology and PERsistence (CLIPER) forecasting scheme. Experimental Long-Lead Forecast Bulletin, 9(2):31-33 (2000).

No abstract.

Landsea, C.W., and J.A. Knaff. Application of the El Ni�o-Southern Oscillation CLImatology PERsistence (CLIPER) forecasting scheme. Experimental Long-Lead Forecast Bulletin, 9(4):48-50 (2000).

No abstract.

Landsea, C.W., and J.A. Knaff. How much "skill" is there in forecasting El Ni�o? Weatherzine, 23:2-4 (2000).

No abstract.

Landsea, C.W., and J.A. Knaff. How much "skill" was there in forecasting the strong 1997-1998 El Ni�o and 1998-2000 La Ni�a events? Proceedings, 25th Annual Climate Diagnostics and Prediction Workshop, Palisades, NY, October 23-27, 2000. NOAA/Climate Prediction Center and the International Research Institute for Climate Prediction, 4-7 (2000).

No abstract.

Landsea C.W., and J.A. Knaff. How much skill was there in forecasting the very strong 1997-1998 El Ni�o? Bulletin of the American Meteorological Society, 81(9):2107-2120 (2000).

The very strong 1997-1998 El Ni�o was the first major event in which numerous forecasting groups participated in its real-time prediction. A previously developed simple statistical tool, the El Ni�o-Southern Oscillation Climatology and Persistence (ENSO-CLIPER) model, is utilized as a baseline for determination of skill in forecasting this event. Twelve statistical and dynamical models were available in real time for evaluation. Some of the models were able to outperform ENSO-CLIPER in predicting either the onset or the decay of the 1997-1998 El Ni�o, but none were successful at both for a medium-range two season (6-8 months) lead time. There were no models, including ENSO-CLIPER, able to anticipate even one-half of the actual amplitude of the El Ni�o's peak at medium-range (6-11 months) lead. In addition, none of the models showed skill (i.e., lower root-mean-square error than ENSO-CLIPER) at the zero season (0-2 months) through the two season (6-8 months) lead times. No dynamical model and only two of the statistical models (the canonical correlation analysis [CCA] and the constructed analog [ANALOG]) outperformed ENSO-CLIPER by more than 5% of the root-mean-square error at the three season (9-11 months) and four season (12-14 months) lead time. El Ni�o impacts were correctly anticipated by national meteorological centers one-half year in advance, because of the tendency for El Ni�o events to persist into and peak during the boreal winter. Despite this, the zero to two season (0-8 month) forecasts of the El Ni�o event itself were no better than ENSO-CLIPER and were in that sense, not skillful, a conclusion that remains unclear to the general meteorological and oceanographic communities.

Landsea, C.W., C. Anderson, N. Charles, G. Clark, J. Fernandez-Partagas, P. Hungerford, C. Neumann, and M. Zimmer. The Atlantic hurricane database re-analysis project: Results for 1851-1885. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 542-543 (2000).

No abstract.

Lawrence, J.R., S.D. Gedzelman, and J.F. Gamache. Tropical cyclogenesis and stable isotope ratios of water. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 260-261 (2000).

No abstract.

Lee, K., F.J. Millero, R.H. Byrne, R.A. Feely, and R. Wanninkhof. The recommended dissociation constants for carbonic acid seawater. Geophysical Research Letters, 27(2):229-232 (2000).

A coherent representation of carbonate dissociation constants and measured inorganic carbon species is essential for a wide range of environmentally important issues such as oceanic uptake of anthropogenic CO₂ and carbon cycle depictions in ocean circulation models. Previous studies have shown varying degrees of discordance between calculated and measured CO₂-system parameters. It is unclear if this is due to errors in thermodynamic models or in measurements. In this work, we address this issue using a large field data set (15,300 water samples) covering all ocean basins. Our field data, obtained using laboratory-calibrated measurement protocols, are most consistent with calculated parameters using the dissociation constants of Mehrbach et al. (1973) as refit by Dickson and Millero (1987). Thus, these constants are recommended for use in the synthesis of the inorganic carbon data collected during the global CO₂ survey during the 1990s and for characterization of the carbonate system in seawater.

Lee, K., R.H. Wanninkhof, R.A. Feely, F.J. Millero, and T.-H. Peng. Global relationships of total inorganic carbon with temperature and nitrate in surface seawater. Global Biogeochemical Cycles, 14(3):979-994 (2000).

High quality total inorganic carbon (C_T) measurements made in the major ocean basins as part of the Joint Global Ocean Flux Study (JGOFS), the National Oceanic and Atmospheric Administration/Ocean Atmosphere Carbon Exchange Study (NOAA/OACES), and the Department of Energy/World Ocean Circulation Experiment (DOE/WOCE) programs are related to sea surface temperature (SST) and nitrate (NO₃^-). A simple two-parameter function with SST and NO₃^- of the form NC_T = a + b SST + c SST² + d NO₃^- fits salinity (S)-normalized surface C_T (NC_T = C_T × 35/S) data for different parts of the oceans within an area-weighted error of ±7 µmol kg^-1 (1 sigma). Estimated values of NC_T using the derived algorithms with NO₃^- and SST are compared with values calculated from the surface partial pressure of CO₂ (pCO_2SW) (Takahashi et al., 1997) and total alkalinity (A_T) (Millero et al., 1998) fields using thermodynamic models. Comparisons of the estimated values of NC_T with measurements not used to derive the same algorithms, and comparisons with the values calculated from global A_T and pCO_2SW fields, give a realistic uncertainty of ±15 µmol kg^-1 in estimated C_T. The derived correlations of NC_T with SST and NO₃^- presented here make it possible to estimate surface C_T over the ocean from climatological SST, S, and NO₃^- fields.

Lee, W.-C., and F.D. Marks. An objective method to determine tropical cyclone center near landfall from WSR-88D data: The GBVTD-simplex algorithm. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 310-311 (2000).

No abstract.

Lee, W.-C., and F.D. Marks. Tropical cyclone kinematic structure retrieved from single Doppler radar observations, Part II: The GBVTD-simplex center finding algorithm. Monthly Weather Review, 128(6):1925-1936 (2000).

This paper is the second of a series and focuses on developing an algorithm to objectively identify tropical cyclone (TC) vorticity centers using single-Doppler radar data. The first paper dealt with the formulation of a single-Doppler radar TC wind retrieval technique, the ground-based velocity-track-display (GBVTD), and the results are verified using analytical TCs. It has been acknowledged that the quality of the GBVTD-retrieved TC circulation strongly depends on accurately knowing its center position. However, existing single-Doppler radar center finding algorithms are limited to estimate centers for axisymmetric TCs. The proposed algorithm uses a simplex method to objectively estimate the TC vorticity center by maximizing GBVTD-retrieved mean tangential wind. When tested with a number of axisymmetric and asymmetric analytical TCs, the accuracy of the TC centers estimated by the GBVTD-simplex algorithm is approximately equal to 340 m from the true center. When adding 5 m s^-1 random noise to the Doppler velocities, the accuracy of the TC centers is nearly unchanged at 350 m. When applying the GBVTD-simplex algorithm to Typhoon Alex (1987), the estimated uncertainty varies between 0.1 and 2 km. When the overall velocity gradient is weak, the uncertainties in the retrieved TC centers are usually large. The GBVTD-simplex algorithm sometimes has problems finding a solution when a large sector of Doppler radar data is missing in conjunction with weak velocity gradients. The GBVTD-simplex algorithm significantly reduces the uncertainties in estimating TC center position compared with existing methods and improves the quality of the GBVTD-retrieved TC circulation. The GBVTD-simplex algorithm is computationally efficient and can be easily adapted for real-time applications.

Lee, W.-C., B. J.-D. Jou, P.-L. Chang, and F.D. Marks. Tropical cyclone kinematic structure retrieved from single-Doppler radar observations. Part III: Evolution and structures of Typhoon Alex (1987). Monthly Weather Review, 128(12):3982-4001 (2000).

This paper is the third of a series that focuses on the applications of the ground-based velocity track display (GBVTD) technique and the GBVTD-simplex center finding algorithm developed in the previous two papers to a real tropical cyclone (TC). The evolution and structure of Typhoon Alex (1987), including full tangential winds, mean radial winds, one component of the mean flow, and their derived axisymmetric angular momentum and perturbation pressure fields are reconstructed from 16 volume scans (6.5 h of data with a 2-h gap) from the Civil Aeronautic Administration (CAA) Doppler radar while Typhoon Alex moved across the mountainous area in northern Taiwan. This analysis retrieves a plausible and physically consistent three-dimensional primary circulation of a landfalling TC using a single ground-based Doppler radar. Highly asymmetric wind structures were resolved by the GBVTD technique where the maximum relative tangential wind at z = 2 km evolved from 52 m s^-1 (before landfall), to less than 40 m s^-1 (after landfall), to less than 35 m s^-1 (entering the East China Sea). Alex's eye began to fill with precipitation while its intensity decreased rapidly after landfall, a characteristic of circulations disrupted by terrain. The mean radial wind field revealed a layer of low-level inflow in agreement with past TC observations. The outward slope of the eyewall reflectivity maximum was consistent with the constant angular momentum contours within the eyewall. After Alex entered the East China Sea, its circulation became more axisymmetric. The axisymmetric perturbation pressure field was retrieved using the gradient wind approximation which, when used in conjunction with one or more surface pressure measurements within the analysis domain, can estimate the central pressure. The retrieved perturbation pressure fields at two time periods were compared with surface pressures reported in northern Taiwan. Considering the assumptions involved and the influence of terrain, good agreement (only 1V2-mb deviation) was found between them. This agreement indicates the relative quality of the GBVTD-retrieved axisymmetric circulation and suggests GBVTD-retrieved quantities can be useful in operational and research applications.

Lonfat, M., F.D. Marks, and S. Chen. A study of the rain distribution in tropical cyclones using TRMM/TMI. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 480-481 (2000).

No abstract.

Luo, J., P.B. Ortner, D. Forcucci, and S.R. Cummings. Diel vertical migration of zooplankton and mesopelagic fish in the Arabian Sea. Deep-Sea Research, Part II, 47(7-8):1451-1473 (2000).

Acoustic (153 kHz ADCP and 12 kHz hull-mounted transducers) data and MOCNESS (MOC01 and MOC10) net tow samples collected in the Arabian Sea during the Spring Intermonsoon (April/May) and Southwest Monsoon (August) in 1995 documented substantial diel migrations of fish and zooplankton despite the year-round presence of an oxygen minimum (<0.2 ml l^-1 at 125-150 m). Fish and zooplankton layers were distinguished by comparing 12 kHz sonar and 153 kHz ADCP backscatter data, which indicated that the strongly migrating layers were predominantly composed of fishes. Fish vertical migration speeds were independently estimated from the slopes of the volume scattering layers and from the vertical velocity components of the ADCP, yielding average speeds of 4 and 3 cm s^-1 and maximum speeds of 13 and 10 cm s^-1, respectively. A few migrating zooplankton layers were identified with an average speed of about 2 cm s^-1 and maximum speeds as high as 8 cm s^-1. Migration depths for both zooplankton and fish differed somewhat amongst stations and appeared to be related to local hydrographic conditions (principally the vertical gradients in DO and water temperature). Zooplankton displacement volumes at individual sites suggested that zooplankton biomass during the Southwest Monsoon could be as much as fivefold greater than during the Spring Intermonsoon. This observation was confirmed for the region in general by first deriving a relationship between ADCP backscatter intensity and daytime zooplankton biomass and then comparing the latter between cruises using daytime ADCP data taken along a 1500 km transect that extended from the coast of Somalia to the center of the northern basin.

Marks, F.D., L. Selevan, and J.F. Gamache. WSR-88D derived rainfall distributions in Hurricane Danny (1997). Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 298-299 (2000).

No abstract.

McAdie, C.J., and P.P. Dodge. Maximum sustained winds in Hurricane Irene as measured by the Miami WSR-88D. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 212-213 (2000).

No abstract.

McArthur, C., R. Ferry, and J.R. Proni. Amenities monitoring for dredged material disposal management. Proceedings, 17th International Conference of the Coastal Society: Coasts at the Millennium, Portland OR, July 9-12, 2000. The Coastal Society, 6 pp. (2000).

Valuable amenities are present throughout U.S. coastal waters, from coral reefs, to oyster beds, to coastal fisheries. In essentially every case in which navigation and/or maintenance dredging is contemplated, the issues of potential impact of dredging activities on nearby amenities arise. In order to evaluate that potential impact, long-term monitoring of amenities is required. Key management issues related to amenities include: (1) reduction or elimination of dredging impacts; (2) scheduling ("windows") for dredging and dredged material disposals; (3) monitoring of transport to, and effects upon amenities; and (4) compliance with defined procedures for dredging activities. While the data needed for management decisions may vary from location to location, certain basic measurement needs appear almost universally: (1) characterization and quantification of dredged sediments arriving at amenities sites; (2) determination of "natural" sediment ranges at amenities sites; (3) photosynthetic light reductions; (4) sediment resuspension and transport; and (5) other sources of materials of potential impact to amenities sites. Dredging and disposal must also be considered in the context of temporal "windows." In the Miami Offshore Disposal Site project, data for management of dredging activities is coordinated between the disposal and amenities (coral reef) sites where dumping windows are determined by realtime current meter data, indicating potential transport to the reef site. In the Pacific Northwest, "curtains" of dredge-related sediment may inhibit upstream spawning activities of valued fisheries resources and thus they are subject to similar temporal windows.

Mestas-Nunez, A.M. Orthogonality properties of rotated empirical modes. International Journal of Climatology, 20(12):1509-1516 (2000).

The properties (spatial orthogonality and temporal uncorrelatedness) of orthogonally-rotated empirical modes depend on the normalization of the modes prior to rotation. It is shown here that these properties also depend on how the empirical modes are formulated. The preferred convention is one that allows us to reconstruct the data from the unrotated or rotated modes. When the empirical modes are normalized so that the spatial eigenvectors are unit length (i.e., EOFs), the rotated modes preserve spatial orthogonality but are no longer temporally uncorrelated. Relaxing the temporal orthogonality in this way does not prejudice conclusions that can be inferred regarding the temporal couplings of the rotated modes.

Mestas-Nunez, A.M., and D.B. Enfield. El Ni�o-Southern Oscillation: Canonical and non-canonical aspects. Proceedings, 24th Annual Climate Diagnostics and Prediction Workshop, Tucson, AZ, November 1-5, 1999. National Weather Service, 111-114 (2000).

The main goal of this paper is to investigate and compare the atmospheric signatures associated with the canonical ENSO and residual components of the SST anomaly variability in the eastern tropical Pacific. An expanded version of this paper will appear in the Journal of Climate (Mestas-Nu�ez and Enfield, 2001).

Molinari, R.L., and J.F. Festa. Effect of subjective choices on the objective analysis of sea surface temperature data in the tropical Atlantic and Pacific Oceans. Oceanologica Acta, 23(1):3-14 (2000).

Many subjective choices are required to perform an objective interpolation (OI) analysis of environmental variables. Herein, we consider the effects on the statistical analysis of sea surface temperature (SST) using (1) a structure function or covariance analysis, (2) different analytical expressions to represent the statistics of the raw data, and (3) different historical SST data sets. The historical data sets are the well-sampled Comprehensive OceanAtmospheric Data Set (COADS) and the poorly sampled historical expendable bathythermograph (XBT) data set. Results from these analyses are used to generate error maps for a poorly-sampled, two month XBT array and a proposed well-sampled profiling float array. For the relatively data-rich COADS analysis, decorrelation scales are the same using either the structure function or covariance analyses. Results differ for the data-poor XBT analysis. Representative decorrelation scales in the Pacific (Atlantic) are about 11-14 (6-10) degrees in the zonal direction and 4-7 (3-6) degrees in the meridional direction. As COADS SST data are less precise than XBT SST data, error and signal variances are greater for the former. The choice of analytical fit to the raw data (needed to generate error maps) has a dramatic effect on the resulting uncertainty fields. Gaussian fits, because of their parabolic shape near the origin, result in smaller errors than exponential fits for the same observing array. Finally, the proposed float array can achieve the accuracies needed to resolve satisfactory upper layer heat content changes over larger areas than the present XBT network.

Morisseau-Leroy, N., M.K. Solomon, and J. Basu. Oracle 8i: Java Component Programming. Osborne McGraw-Hill (ISBN 0072127376), 697 pp. (2000).

No abstract.

Murillo, S.T., W.-C. Lee, and F.D. Marks. Evaluating the GBVTD-tropical center finding simplex algorithm. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 312-313 (2000).

The GBVTD simplex algorithm has been tested using axisymmetric and asymmetric analytic tropical cyclones by Lee et al. (1999). The algorithm objectively identifies the tropical cyclone center by maximizing the GBVTD-derived mean tangential wind field. Lee and Marks (1999) applied the GBVTD simplex algorithm to Typhoon Alex (1987). However, a true center was not available to verify the accuracy of the algorithm. This study applies the GBVTD simplex algorithm to Hurricane Danny (1997). The estimated storm track derived by the algorithm is compared to radar and aircraft storm fixes. The derived track is in good agreement with the true storm track within 2 km. Results will be presented that show how the GBVTD simplex algorithm improves the quality of the GBVTD retrieved wind analysis.

Murnane, R.J., C. Barton, E. Collins, J. Donnelly, J. Elsner, K. Emanuel, I. Ginis. S. Howard, C.W. Landsea, K. Liu, D. Malmquist, M. McKay, A. Michaels, N. Nelson, J. O'Brien, D. Scott, and T. Webb. Model estimates of hurricane wind speed probabilities. EOS, Transactions, American Geophysical Union, 81(38):433, 438 (2000).

No abstract.

Nelsen, T.A., S.J. Stamates, B.J. Elkind, W.P. Dammann, and J.R. Proni. Field evaluation of the temporal and spatial variations in total suspended matter and current fields at Chesapeake Bay Site 104 and contiguous areas. Final Report, U.S. Army Corps of Engineers, MIPR No. W81W3@00604995, 47 pp. (2000).

No abstract.

Nolan, D.S., M.T. Montgomery, and P.D. Reasor. Studies of the wavenumber one instability in hurricane-like vortices. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 29-30 (2000).

No abstract.

Ooyama, K.V. A dynamic and thermodynamic foundation for modeling the moist atmosphere with classical thermodynamics and parameterized microphysics. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 561-562 (2000).

No abstract.

Otero, S., N. Morisseau-Leroy, N. Carrasco, and M.D. Powell. A distributed real-time hurricane wind analysis system. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 197-198 (2000).

No abstract.

Parrish, J.R., M.L. Black, S.H. Houston, P.P. Dodge, and J.J. Cione. The structure of Hurricane Irene over South Florida. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 456-457 (2000).

No abstract.

Peng, T.-H., and F. Chai. Modeling the carbon cycle in the equatorial Pacific Ocean. Proceedings, Marine Environment: The Past, Present, and Future, Kaohsiung, Taiwan, January 26-28, 1999. Sueichan Press, 240-255 (2000).

An ocean ecosystem model of the equatorial Pacific Ocean has been developed with new and export productivity regulated by Si and Fe to synthesize and analyze data collected during the JGOFS process-study-oriented survey cruises in 1992. The data also include those obtained by NOAA/OACES cruises in concert with the JGOFS EqPac process study. The circulation model is based on the Modular Ocean Model of the NOAA/GFDL ocean general circulation model. The ecosystem model is originally formulated by Chai et al. (1996), and is now expanded to consist of nine components describing two sizes of phytoplankton, two sizes of zooplankton, two detritus pools, and three dissolved nutrients: silicate, nitrate, and ammonium. The carbonate chemistry is parameterized in the model to evaluate the variations of pCO₂ and, hence, the CO₂ flux across the air-sea interface. At this initial stage, a test case by using a 1D model is performed to simulate low-silicate, high-nitrate, and low-chlorophyll conditions in the equatorial Pacific, and to investigate how the carbon system behaves in this ecosystem structure. The model includes the vertical upwelling and diffusion processes. The modeled upwelling rate and vertical diffusivity, from a 3D circulation model, were initially averaged for the region with latitudes 5°S to 5°N, and longitude 180° to 90°W, the "cold tongue" of the equatorial Pacific. Temperature is used to calibrate model upwelling and vertical diffusion rates. Comparison of model results with the observations made during the NOAA/OACES EqPac 1992 expeditions indicates that the vertical profiles of DIC, NO₃, and Si(OH)₄ are consistent with the measurements made in the fall season when the ocean was in a normal non-El Ni�o condition. A tight fit of profiles between model and observation is not possible because of spatial variations of the observed values. A 3D simulation is required, which is in progress. The 1D model CO₂ evasion rate is estimated to be 2.9 mol/m²/yr, which is consistent with the range of estimates from measurements made during non-El Ni�o conditions.

Powell, M.D. Tropical cyclones during and after landfall. In Storms (Volume 1), R. Pielke, Sr. and R. Pielke, Jr. (eds.). Routledge, New York (ISBN 041517239X), 196-219 (2000).

No abstract.

Proni, J.R. Using acoustical methods to study and monitor the discharge of sewage and dredged-material in the coastal ocean. Proceedings, Fifth European Conference on Underwater Acoustics (ECUA 2000), Lyon, France, July 10-13, 2000. European Acoustics Association, Volume 1, 755-760 (2000).

Acoustical backscatter has been shown to be very effective in the study and monitoring of sewage efffluent and dredged material released into the coastal waters. Acoustical detection of a detrainment phenomenon in discharge plumes shows the extreme sensitivity of effluent distributions to small water column density changes. Acoustic measurements, as part of an ensemble of sensor systems, reveal turbidity changes occurring at environmentally valuable biological communities such as coral reefs and oyster beds. Examples of acoustic observations are presented.

Protat, A., Y. Lemaitre, D. Bouniol, and R.A. Black. Microphysical observations during FASTEX from airborne Doppler radar and in-situ measurements. Physics and Chemistry of the Earth, Part B: Hydrology, Oceans, and Atmosphere, 25(10-12):1097-1102 (2000).

A major objective of FASTEX is to document the three-dimensional dynamic and microphysical structure of the North-Atlantic frontal cyclones in their mature stage at different scales of motion. In this paper, we combine the airborne Doppler radar and microphysical 2D-C and 2D-P probes data to recover the 3D microphysical and radiative properties of the IOP16 and IOP12 frontal cyclones (terminal fall velocity, cloud and precipitation water contents, precipitation fall rate, effective radius). The first step is to derive statistical relationships between the microphysical quantities and reflectivity from the 2D-P and 2D-C probes. Then, the Doppler-derived 3D reflectivity field is combined with these statistical relationships to access the 3D microphysical fields.

Quilfen Y., A. Bentamy, P. Delecluse, K.B. Katsaros, and N. Grima. Prediction of sea level anomalies using ocean circulation model forced by scatterometer wind and validation using TOPEX/Poseidon data. IEEE Transactions on Geoscience and Remote Sensing, 38(4):1871-1884 (2000).

Uncertainties in the surface wind field have long been recognized as a major limitation in the interpretation of results obtained by oceanic circulation models. It is especially true in the tropical oceans, where the response to wind forcing is very strong on short time scales. The purpose of this paper is to show that these uncertainties can be greatly reduced by using spaceborne wind sensors that provide accurate measurements on a global basis. Surface winds over the global oceans have been measured by scatterometry since the launch of the European Remote Sensing Satellite (ERS-1) in August 1991 by the European Space Agency, Noordwijk, The Netherlands, and is currently provided by ERS-2, launched in April 1995. The ground-track wind vectors are processed to compute mean weekly surface winds onto a 1° square grid at the Institut Francais de Recherche pour l'Exploitation de la Mer (IFREMER), Plouzane, France. These winds are validated by comparison with the buoy array in the tropical Pacific Ocean, showing good agreement. In order to further evaluate this wind field, the three-dimensional ocean model OPA7 developed at Laboratoire d'Oc�anographie Dynamique et de Climatologie, Paris, France, is forced over the tropical oceans by the ERS-derived wind stress fields and by fields from the atmospheric model "Arpege/Climat." Selected ocean parameters are defined in order to validate the ocean model results with measurements of the tropical ocean and global atmosphere (TOGA) buoys in the Pacific Ocean. The ability of the model to describe the short scale (a few weeks to a few years) oceanic variability is greatly enhanced when the satellite-derived surface forcing is used. In this paper, we present further comparison of the ocean model results with the TOPEX-Poseidon altimeter measurements. Simulated and measured sea level variability are described over the three tropical oceans. The annual and semi-annual signals, as well as the interannual variability, partly linked to the El Ni�o-Southern Oscillation (ENSO) phenomenon, are well simulated by the OPA7 model when the satellite winds are used. Furthermore, it shows that the objective method, kriging technique, used to interpolate the mean ERS wind fields, dramatically reduces the effects of the satellite bandlike sampling. In the last part of this paper, we focus on the relationship between the wind stress anomalies and the sea level anomalies in the case of the 1997-1998 El Ni�o event. It clearly shows that sea level anomalies in the eastern and western parts of the Pacific are strongly linked to wind stress anomalies in the central Pacific. The forthcoming scatterometers aboard the METOP and ADEOS satellites will provide a much better coverage. It will enable the wind variability spatial and temporal scales to be resolved better, in order that wind uncertainties no longer blur the interpretation of ocean circulation numerical model results.

Reasor, P.D., and M.T. Montgomery. 3D alignment and co-rotation of weak, TC-like vortices via linear vortex Rossby waves. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 268-269 (2000).

No abstract.

Reasor, P.D., M.T. Montgomery, F.D. Marks, and J.F. Gamache. Low-wavenumber structure and evolution of the hurricane inner core observed by airborne dual-Doppler radar. Monthly Weather Review, 128(6):1653-1680 (2000).

The asymmetric dynamics of the hurricane inner-core region is examined through a novel analysis of high temporal resolution, three-dimensional wind fields derived from airborne dual-Doppler radar. Seven consecutive composites of Hurricane Olivia's (1994) wind field with 30-min time resolution depict a weakening storm undergoing substantial structural changes. The symmetric and asymmetric mechanisms involved in this transformation are considered separately. To zeroth order the weakening of the primary circulation is consistent with the axisymmetric vortex spindown theory of Eliassen and Lystad for a neutrally-stratified atmosphere. Vertical shear, however, increased dramatically during the observation period, leading to a strong projection of the convection onto an azimuthal wavenumber 1 pattern oriented along the maximum vertical shear vector. Recent theoretical ideas elucidating the dynamics of vortices in vertical shear are used to help explain this asymmetry. The role of asymmetric vorticity dynamics in explaining some of the physics of hurricane intensity change motivates a special focus on Olivia's vorticity structure. It is found that an azimuthal wavenumber 2 feature dominates the asymmetry in relative vorticity below 3-km height. The characteristics of this asymmetry deduced from reflectivity and wind composites during a portion of the observation period show some consistency with a wavenumber 2 discrete vortex Rossby edge wave. Barotropic instability is suggested as a source for the wavenumber 2 asymmetry through a series of barotropic numerical simulations. Trailing bands of vorticity with radial wavelengths of 5-10 km are observed in the inner core approximately 20 km from the storm center, and may be symmetrizing vortex Rossby waves. Elevated reflectivity bands with radial scales comparable to those of the vorticity bands, also near 20-25-km radius, may be associated with these vorticity features.

Rogers, R.F. Surface-based modification of convectively-generated mesovortices and its implications for tropical cyclogenesis. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 151-152 (2000).

No abstract.

Rogers, R.F., J.M. Fritsch, and W.C. Lambert. A simple technique for using radar data in the dynamic initialization of a mesoscale model. Monthly Weather Review, 128(7):2560-2574 (2000).

A simple technique for using radar reflectivity to improve model initialization is presented. Unlike previous techniques, the scheme described here does not infer rain rates and heating profiles from assumed relationships between remotely-sensed variables and precipitation rates. Rather, the radar data are only used to tell the model when and where deep moist convection is occurring. This information is then used to activate the model's convective parameterization scheme in the grid elements where convection is observed. This approach has the advantage that the convective precipitation rates and heating profiles generated by the convective parameterization are compatible with the local (grid element) environment. The premise is that if convection is forced to develop when and where it is observed during a data assimilation period, convectively-forced modifications to the environment will be in the correct locations at the model initial forecast time and the resulting forecast will be more accurate. Three experiments illustrating how the technique is applied in the simulation of deep convection in a warm-season environment are presented: a control run in which no radar data are assimilated, and two additional runs where radar data are assimilated for 12 h in one run and 24 h in the other. The results indicate that assimilating radar data can improve a model's description of the mesoscale environment during the pre-forecast time period, thereby resulting in an improved forecast of precipitation and the mesoscale environment.

Rogers, R.F., S.S. Chen, J.E. Tenerelli, and M. Lonfat. A numerical study of the distribution of precipitation in Hurricane Bonnie (1998). Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 408-409 (2000).

No abstract.

Sabine, C.L., R.H. Wanninkhof, R.M. Key, C. Goyet, and F.J. Millero. Seasonal CO₂ fluxes in the tropical and subtropical Indian Ocean. Marine Chemistry, 72(1):33-53 (2000).

Improved estimates of the variability in air-sea CO₂ fluxes on seasonal and interannual time scales are necessary to help constrain the net partitioning of CO₂ between the atmosphere, oceans, and terrestrial biosphere. Few direct measurements of the carbon system have been made in the main Indian Ocean basin. In the mid 1990s, several global carbon measurement programs focused on the Indian Ocean, greatly increasing the existing carbon database for this basin. This study examines the combined surface CO₂ measurements from three major U.S. programs in the Indian Ocean: the global carbon survey cruises, conducted in conjunction with the World Ocean Circulation Experiment (WOCE); the NOAA Ocean-Atmosphere Carbon Exchange Study (OACES) Indian Ocean survey; and the Joint Global Ocean Flux Study (JGOFS) Arabian Sea Process Study. These data are fit with multiparameter linear regressions as a function of commonly-measured hydrographic parameters. These fits are then used with NCEP/NCAR reanalysis and Levitus 94 gridded values to evaluate the seasonal variability of surface seawater CO₂ in the tropical and subtropical Indian Ocean and to estimate the magnitude of the Indian Ocean as a net sink for atmospheric CO₂. The net annual flux for the Indian Ocean (north of 36°S) was -12.4 � 0.5 × 10¹² mol of carbon (equivalent to -0.15 Pg C) in 1995. The relatively small net flux results from the very different surface water pCO₂ distributions and seasonal variations in the northern and southern Indian Ocean. The equatorial and northern hemisphere regions have values that are generally above atmospheric values. During the southwest monsoon, pCO₂ values in the Arabian Sea coastal upwelling region are among the highest observed in the oceans. The upwelling is seasonal in nature, however, and only affects a relatively small area. The Indian Ocean equatorial region generally has values slightly above atmospheric. Unlike the Pacific and Atlantic Oceans, however, no clear equatorial upwelling signature was observed in 1995. The Southern Hemisphere Indian Ocean, which represents the largest region by area, generally has values below atmospheric. The strongest undersaturations are observed in the austral winter, with summer values reaching near or slightly above atmospheric.

Sabine, C.L., M.F. Lamb, J.L. Bullister, R.A. Feely, G.L. Johnson, R.M. Key, A. Kozyr, K. Lee, F.J. Millero, T.-H. Peng, and R.H. Wanninkhof. U.S. JGOFS team examines Pacific Ocean CO₂ data quality. International WOCE Newsletter, 38:10-14 (2000).

No abstract.

Sandrik, A., C.W. Landsea, and B. Jarvinen. The North Florida hurricane of 29 September 1896: A historical case of extreme inland high winds. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 547-548 (2000).

No abstract.

Schmid, C., G. Siedler, and W. Zenk. Dynamics of intermediate water circulation in the subtropical South Atlantic. Journal of Physical Oceanography, 30(12):3191-3211 (2000).

The circulation of the low-salinity Antarctic Intermediate Water in the South Atlantic and the associated dynamical processes are studied, using recent and historical hydrographic profiles, Lagrangian and Eulerian current measurements as well as wind stress observations. The circulation pattern inferred for the Antarctic Intermediate Water supports the hypothesis of an anticyclonic basin-wide recirculation of the intermediate water in the subtropics. The eastward current of the intermediate anticyclone is fed mainly by water recirculated in the Brazil Current and by the Malvinas Current. An additional source region is the Polar Frontal Zone of the South Atlantic. The transport in the meandering eastward current ranges from 6 Sv to 26 Sv (1 Sv = 10⁶ m³ s^-1). The transport of the comparably uniform westward flow of the gyre varies between 10 Sv and 30 Sv. Both transports vary with longitude. At the western boundary near 28°S, in the Santos Bifurcation, the westward current splits into two branches. About three quarters of the 19 Sv at 40°W go south as an intermediate western boundary current. The remaining quarter flows northward along the western boundary. Simulations with a simple model of the ventilated thermocline reveal that the wind-driven subtropical gyre has a vertical extent of over 1200 m. The transports derived from the simulations suggest that about 90% of the transport in the westward branch of the intermediate gyre and about 50% of the transport in the eastward branch can be attributed to the wind-driven circulation. The structure of the simulated gyre deviates from observations to some extent. The discrepancies between the simulations and the observations are most likely caused by the interoceanic exchange south of Africa, the dynamics of the boundary currents, the nonlinearity, and the seasonal variability of the wind field. A simulation with an inflow/outflow condition for the eastern boundary reduces the transport deviations in the eastward current to about 20%. The results support the hypothesis that the wind field is of major importance for the subtropical circulation of Antarctic Intermediate Water followed by the interoceanic exchange. The simulations suggest that the westward transport in the subtropical gyre undergoes seasonal variations. The transports and the structure of the intermediate subtropical gyre from the Parallel Ocean Climate Model (Semtner/Chervin model) agree better with observations.

Schott, F., C. Boning, H. Bryden, R.L. Molinari, P. Schlosser, C. Wunsch, and L. Stramma. 2000 Report of the WOCE North Atlantic Workshop. WOCE Report No. 169/2000, 110 pp. (2000).

No abstract.

Schubert, W.H., S.A. Hausman, M. Garcia, K.V. Ooyama, and H.-C. Kuo. Potential vorticity in a moist atmosphere. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 563-564 (2000).

No abstract.

Shay, L., G.J. Goni, and P.G. Black. Effects of a warm oceanic feature on Hurricane Opal. Monthly Weather Review, 128(5):1366-1383 (2000).

On 4 October 1995, Hurricane Opal deepened from 965 to 916 hPa in the Gulf of Mexico over a 14-h period upon encountering a warm core ring (WCR) in the ocean shed by the Loop Current during an upper-level atmospheric trough interaction. Based on historical hydrographic measurements placed within the context of a two-layer model and surface height anomalies (SHA) from the radar altimeter on the TOPEX mission, upper-layer thickness fields indicated the presence of two warm core rings during September and October 1995. As Hurricane Opal passed directly over one of these WCRs, the 1-min surface winds increased from 35 to more than 60 m s^-1, and the radius of maximum wind decreased from 40 to 25 km. Pre-Opal SHAs in the WCR exceeded 30 cm where the estimated depth of the 20°C isotherm was located between 175 and 200 m. Subsequent to Opal's passage, this depth decreased approximately 50 m, which suggests upwelling underneath the storm track due to Ekman divergence. The maximum heat loss of approximately 24 Kcal cm^-2 relative to depth of the 26°C isotherm was a factor of 6 times the threshold value required to sustain a hurricane. Since most of this loss occurred over a period of 14 h, the heat content loss of 24 Kcal cm^-2 equates to approximately 20 kW m^-2. Previous observational findings suggest that about 10%-15% of upper-ocean cooling is due to surface heat fluxes. Estimated surface heat fluxes based upon heat content changes range from 2000 to 3000 W m^-2 in accord with numerically simulated surface heat fluxes during Opal's encounter with the WCR. Composited AVHRR-derived SSTs indicated a 2°-3°C cooling associated with vertical mixing in the along-track direction of Opal except over the WCR where AVHRR-derived and buoy-derived SSTs decreased only by about 0.5°-1°C. Thus, the WCR's effect was to provide a regime of positive feedback to the hurricane rather than negative feedback induced by cooler waters due to upwelling and vertical mixing as observed over the Bay of Campeche and north of the WCR.

Shay, L.K., G.J. Goni, P.G. Black, S.D. Jacob, J.J. Cione, and E.W. Uhlhorn. Global analogues of deep warm upper ocean layers: Hurricane heat potential estimates. Proceedings, 10th Conference on Interaction of the Sea and Atmosphere, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, J3-J4 (2000).

No abstract.

Spratt, S.M., F.D. Marks, P.P. Dodge, and D.W. Sharp. Examining the pre-landfall environment of mesovortices within a Hurricane Bonnie (1998) outer rainband. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 300-301 (2000).

No abstract.

Tenerelli, J.E., S.S. Chen, M. Lonfat, R. Foster, and R.F. Rogers. Surface winds in Hurricane Floyd: A comparison between numerical simulations, aircraft data, and QuikScat satellite data. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 418-419 (2000).

No abstract.

Uhlhorn, E.W., K.B. Katsaros, and M.D. Powell. Assimilation of scatterometer-derived winds into real-time tropical cyclone surface wind analyses. Preprints, 10th Conference on Satellite Meteorology and Oceanography, Long Beach, CA, January 9-14, 2000. American Meteorological Society, Boston, 214-215 (2000).

No abstract.

Uhlhorn, E.W., P.G. Black, L.K. Shay, J.J. Cione, S.D. Jacob, and G.J. Goni. Warm core ocean features in the central and eastern Gulf of Mexico. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 147-148 (2000).

No abstract.

Wainer, I., P. Gent, and G.J. Goni. Annual cycle of the Brazil-Malvinas confluence region in the National Center for Atmospheric Research climate system model. Journal of Geophysical Research, 105(C11):26,167-26,177 (2000).

The objective of this study is to compare the mean and seasonal variability of the circulation in the southwest Atlantic with observations. The results used in the comparison are from the last 200 years of a 300-year control integration of the Climate System Model (CSM). The area of study includes the confluence region between the subtropical and subpolar waters represented by the Brazil and Malvinas Currents. The seasonal variation of transport and its relationship to changes in the wind stress forcing and in the sea surface temperature are examined and compared to available oceanographic observations. This study shows that a coarse resolution climate model, such as the CSM, can successfully reproduce major characteristics of the Brazil-Malvinas confluence seasonality, although the mesoscale features involving recirculation and meander dynamics are not resolved. The CSM transport values in the region of 38°S are consistent with hydrographically-derived values. The transport of the CSM Brazil Current is higher during austral summer and smaller during austral winter. Conversely, the Malvinas Current transport is weaker during austral summer and stronger during austral winter. This is also consistent with observations. The CSM seasonal cycle in transport associated with both the Brazil and Malvinas Currents and its meridional displacement is closely linked to the seasonal variations in the local wind stress curl. However, the displacement is much smaller in the model than in observations. The CSM results show that the latitudinal displacement of the 24°C and 17°C at the South American coast between austral summer and winter is 20° and 12°, respectively. This is very similar to the displacement seen in observations.

Walsh, E.J., C.W. Wright, D.C. Vandemark, W.B. Krabill, A.W. Garcia, S.H. Houston, M.D. Powell, P.G. Black, and F.D. Marks. Hurricane directional wave spectrum spatial variation at landfall. Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 327-328 (2000).

No abstract.

Wang, C. A unified theory for the El Ni�o-Southern Oscillation. Proceedings, 10th Conference on Interaction of the Sea and Atmosphere, Ft. Lauderdale, Florida, May 29-June 2, 2000. American Meteorological Society, Boston, J42-J43 (2000).

No abstract.

Wang, C. On the atmospheric responses to tropical Pacific heating during the mature phase of El Ni�o. Journal of the Atmospheric Sciences, 57(22):3767-3781 (2000).

The atmospheric heating and sea surface temperature (SST) anomalies during the mature phase of El Ni�o are observed to show both eastern and western Pacific anomaly patterns, with positive anomalies in the equatorial eastern/central Pacific and negative anomalies in the off-equatorial western Pacific. The detailed spatial patterns of the heating anomalies differ from the SST anomalies. The heating anomalies are more equatorially confined than the SST anomalies, and maxima of positive and negative heating anomalies are located farther to the west than the SST anomalies. The Gill/Zebiak atmospheric model assumes that the atmospheric initial heating has the same spatial patterns as the SST anomalies. This assumption results in some unrealistic model simulations for El Ni�o. When the model heating anomaly forcing is modified to resemble the observed heating anomalies during the mature phase of El Ni�o, the model simulations have been improved to: (1) successfully simulate equatorial easterly wind anomalies in the western Pacific; (2) correctly simulate the position of maximum westerly wind anomalies; and (3) reduce unrealistic easterly wind anomalies in the off-equatorial eastern Pacific. This paper shows that off-equatorial western Pacific negative atmospheric heating (or cold SST) anomalies are important in producing equatorial easterly wind anomalies in the western Pacific. These off-equatorial cold SST anomalies in the western Pacific also contribute to equatorial westerly wind anomalies observed in the central Pacific during the mature phase of El Ni�o. Although off-equatorial cold SST anomalies in the western Pacific are smaller than equatorial positive SST anomalies in the eastern Pacific, they are enough to produce atmospheric responses of comparable magnitude to the equatorial eastern Pacific. This is because the atmospheric mean state is convergent in the western Pacific and divergent in the equatorial eastern Pacific. By either removing the atmospheric mean convergence or removing off-equatorial cold SST anomalies in the western Pacific, the atmospheric responses show no equatorial easterly wind anomalies in the western Pacific. In the Gill/Zebiak model, the mean wind divergence field is an important background state, whereas the mean SST is secondary.

Wang, C., and R.H. Weisberg. The 1997-1998 El Ni�o evolution relative to previous Ni�o events. Journal of Climate, 13(2):488-501 (2000).

The evolution of the 1997-1998 El Ni�o is described using NCEP sea surface temperature (SST) and outgoing longwave radiation (OLR) data, NCEP-NCAR reanalysis sea level pressure (SLP) fields, and FSU surface wind data. From November 1996 to January 1997, the eastern Pacific is characterized by equatorial cold SST and high SLP anomalies, while the western Pacific is marked by off-equatorial warm SST anomalies and off-equatorial anomalous cyclones. Corresponding to this distribution are high OLR anomalies in the equatorial central Pacific and low OLR anomalies in the off-equatorial far western Pacific. The off-equatorial anomalous cyclones in the western Pacific are associated with a switch in the equatorial wind anomalies over the western Pacific from easterly to westerly. These equatorial westerly anomalies then appear to initiate early SST warmings around the date line in January/February 1997 and around the far eastern Pacific in March 1997. Subsequently, both the westerly wind and warm SST anomalies, along with the low OLR anomalies, grow and progress eastward. The eastward propagating warm SST anomalies merge with the slower westward spreading warm SST anomalies from the far eastern Pacific to form large-scale warming in the equatorial eastern and central Pacific. The anomaly patterns in the eastern and central Pacific continue to develop, reaching their peak values around December 1997. In the western Pacific, the off-equatorial SST anomalies reverse sign from warm to cold. Correspondingly, the off-equatorial SLP anomalies in the western Pacific also switch sign from low to high. These off-equatorial high SLP anomalies initiate equatorial easterly wind anomalies over the far western Pacific. Like the equatorial westerly wind anomalies that initiate the early warming, the equatorial easterly wind anomalies over the far western Pacific appear to have a cooling effect in the east and, hence, help facilitate the 1997-1998 El Ni�o decay. The paper also compares the 1997-1998 El Ni�o with previous warm events, and discusses different ENSO mechanisms relevant to the 1997-1998 El Ni�o.

Wilkerson, J.C., and J.R. Proni. Monitoring tropical and subtropical rainfall over the ocean using underwater acoustic techniques. Proceedings, Fifth European Conference on Underwater Acoustics (ECUA 2000), Lyon, France, July 10-13, 2000. European Acoustics Association, Volume 1, 741-746 (2000).

Measurements of underwater sound produced by rain were made at three U.S. coastal sites to determine feasibility and limitations of acoustic detection and classification of rainfall over water. In the study, concurrent radar observations were used to identify convective and stratiform regions of the precipitating clouds overhead. Acoustic-derived classifications of rain type, based on information in the 4-30 kHz frequency band, were in general agreement with radar-derived classifications. A correlation of 0.9 was found to exist between sound spectrum levels (in decibels) in the 4-10 kHz frequency band and rain rate, suggesting the use of acoustical methods for rainfall estimation. Testing of the acoustic technique in deep water is currently underway at the U.S. Navy Atlantic Undersea Test and Evaluation Center, Bahamas. Examples of acoustic spectra are presented.

Willoughby, H.E. and R.W. Jones. Are the beta gyres really normal modes? Preprints, 24th Conference on Hurricanes and Tropical Meteorology, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, 187-188 (2000).

No abstract.

Wilson, W.D., and K.D. Leaman. Transport pathways through the Caribbean: The tropical origins of the Gulf Stream. Journal of Marine Education, 16(1):14-18 (2000).

No abstract.

Wright, C.W., E.J. Walsh, D.C. Vandemark, W.B. Krabill, A.W. Garcia, S.H. Houston, M.D. Powell, P.G. Black, and F.D. Marks. Hurricane directional wave spectrum spatial variation in the open ocean. Proceedings, 10th Conference on Interaction of the Sea and Atmosphere, Ft. Lauderdale, FL, May 29-June 2, 2000. American Meteorological Society, Boston, J1-J2 (2000).

No abstract.

Yao, Q., S.L. Garzoli, R. Zantopp, and W.E. Johns. North Brazil Current Rings Experiment: Time series data report. NOAA Data Report (PB2001-106244), OAR AOML-40, 104 pp. (2000).

This data report presents the data collected through moored instrumentation during the North Brazil Current Rings Experiment, a joint effort between the University of Miami's Rosenstiel School of Marine and Atmospheric Science, NOAA's Atlantic Oceanographic and Meteorological Laboratory, the Woods Hole Oceanographic Institution, and Columbia University's Lamont Doherty Earth Observatory. The program is funded by the National Science Foundation (NSF) and the National Oceanic and Atmospheric Administration (NOAA). The main goal of this program is to study the contribution of the North Brazil Current (NBC) rings to inter-hemispheric exchange of heat and salt and to determine their role in climate.

Yvon-Lewis, S.A. Methyl bromide in the atmosphere and ocean. IGACtivities Newsletter, 19:9-12 (2000).

No abstract.

Zhang, J.-Z. Shipboard automated determination of trace concentrations of nitrite and nitrate in oligotrophic water by gas-segmented continuous flow analysis with a liquid waveguide capillary flow cell. Deep-Sea Research, Part I, 47(6):1157-1171 (2000).

Incorporation of a liquid waveguide capillary flow cell to a gas-segmented continuous flow auto-analyzer significantly enhances the sensitivity of automated colorimetric analysis. Nanomolar concentrations of nitrite and nitrate in oligotrophic surface seawater can be accurately determined. The advantages of this technique are low detection limit, high precision, and automation for rapid analysis of a large number of samples. This technique has been successfully used on shipboard measurements of about 1000 seawater samples during a one-month cruise in North Atlantic.

Zhang, J.-Z. The use of pH and buffer intensity to quantify the carbon cycle in the ocean. Marine Chemistry, 70(1-3):121-131 (2000).

The pH of seawater is governed by the content of total carbon dioxide and ionic equilibra between hydrogen ions and various inorganic carbon species in seawater. Buffer intensity is defined as a measure of the ability of seawater to accommodate the addition of acid or base without appreciable pH change. It can be calculated from pH and total carbon dioxide of seawater. pH data in conjunction with buffer intensity can be used to quantify the carbon cycle in the ocean. The total amount of acid that has been released or consumed by any biogeochemical processes can be calculated from the change in pH multiplied by buffer intensity of seawater, dC_H = d(beta-pH). This approach has been used to quantify the remineralization process in the Antarctic Intermediate Water in the South Pacific. Based on the observational data (pH, total carbon dioxide, O₂, and nutrient measurements on P18 cruise), calculated elemental remineralization ratios are 173, 107, and 14.3 for O/P, C/P and N/P, respectively. The dissolution of calcium carbonate accounts for 21.5% of carbon increased from the remineralization in the Antarctic Intermediate Water.

Zhang, J.-Z., C.J. Fischer, and P.B. Ortner. Comparison of open tubular cadmium reactors and packed cadmium columns in automated gas-segmented continuous flow nitrate analysis. International Journal of Environmental Analytical Chemistry, 76(2):99-113 (2000).

Detailed procedures are provided for preparing packed cadmium columns to reduce nitrate to nitrite. Experiments demonstrated the importance of conditioning both open tubular cadmium reactor (OTCR) and packed copper-coated cadmium columns to achieve 100% reduction efficiency. The effects of segmentation bubbles in the OTCR upon reduction efficiency and baseline noise in nitrate analysis are investigated using an auto-analyzer. Metal particles derived from segmentation bubbles in OTCR result in i nterference with continuous flow analyses. Therefore, packed columns are recommended for determination of low level nitrate in natural waters.

Zhang, J.-Z., R.H. Wanninkhof, and K. Lee. New production in oligotrophic waters: Estimation based on diel cycle of nitrate. Proceedings, Joint Global Ocean Flux Study (JGOFS) Open Science Conference, Bergen, Norway, April 13-17, 2000. JGOFS International Project Office, 76-77 (2000).

New production can be estimated from accurate measurements of inventory change in nitrate at nM levels in the photic zone. A strong diel cycle was observed in nitrate concentrations in response to photosynthesis in the eastern North Atlantic during the GASEX-98 cruise. During a diel study, nitrate concentration was 92 nM in the morning and decreased to 12 nM by 6 p.m. It increased after dark, presumably due to the diffusive flux from the nitracline. Oxygen showed a similar diel cycle with a change in concentration of about 2 µM. The vertical eddy diffusivity was derived from temporal changes in concentrations of a deliberate tracer, SF6, below the mixed layer. Together with vertical nitrate distributions, the nitrate flux from nitracline throughout the nighttime can account for a nitrate concentration of 102 nM by morning, which is in good agreement with measured nitrate of 92 nM at 6 a.m. The new production estimated from changes of nitrate inventory in the photic zone during the day was 28 mmole C/m² d. Increases in the mixed layer nitrate were observed during storm events that deepened the mixed layer and brought the nitrate to the surface. The storm-induced nitrate disappeared within two days, indicating a rapid uptake by phytoplankton. The relative importance of sporadic storm events versus daily diffusive flux in supply nitrate to new production can be estimated based on nitrate inventory changes in the photic zone.

Zhang, J.-Z., C.W. Mordy, L.I. Gordon, A. Ross, and H.E. Garcia. Temporal trends in deep ocean Redfield ratios. Science, 289(5486):1839 (2000).

No abstract. **1999**

Aberson, S.D. Ensemble-based products to improve tropical cyclone forecasting. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 843-844 (1999).

No abstract.

Aberson, S.D. Targeting and sampling strategies to improve hurricane forecasts. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 105-107 (1999).

No abstract.

Aberson, S.D., and J.L. Franklin. Impact on hurricane track and intensity forecasts of GPS dropwindsonde observations from the first-season flights of the NOAA Gulfstream-IV jet aircraft. Bulletin of the American Meteorological Society, 80(3):421-428 (1999).

In 1997, the Tropical Prediction Center (TPC) began operational Gulfstream-IV jet aircraft missions to improve the numerical guidance for hurricanes threatening the continental United States, Puerto Rico, and the Virgin Islands. During these missions, the new generation of Global Positioning System dropwindsondes were released from the aircraft at 150-200-km intervals along the flight track in the environment of the tropical cyclone to obtain profiles of wind, temperature, and humidity from flight level to the surface. The observations were ingested into the global model at the National Centers for Environmental Prediction, which subsequently served as initial and boundary conditions to other numerical tropical cyclone models. Because of a lack of tropical cyclone activity in the Atlantic basin, only five such missions were conducted during the inaugural 1997 hurricane season. Due to logistical constraints, sampling in all quadrants of the storm environment was accomplished in only one of the five cases during 1997. Nonetheless, the dropwindsonde observations improved mean track forecasts from the Geophysical Fluid Dynamics Laboratory hurricane model by as much as 32%, and the intensity forecasts by as much as 20% during the hurricane watch period (within 48 h of projected landfall). Forecasts from another dynamical tropical cyclone model (VICBAR) also showed modest improvements with the dropwindsonde observations. These improvements, if confirmed by a larger sample, represent a large step toward the forecast accuracy goals of TPC. The forecast track improvements are as large as those accumulated over the past 20-25 years, and those for forecast intensity provide further evidence that better synoptic-scale data can lead to more skillful dynamical tropical cyclone intensity forecasts.

Albrecht, B., T. Faber, A. Savtchenko, D. Churchill, F.D. Marks, and P.G. Black. Surface-based remote sensing of a landfalling tropical storm. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 489-492 (1999).

No abstract.

Alfaro, E.J., and D.B. Enfield. The rainy season in Central America: An initial success in prediction. IAI Newsletter, 20:21-22 (1999).

No abstract.

Amat, L.R., M.D. Powell, and S.H. Houston. A real-time, Internet-based application for the archival, quality control, and analysis of hurricane surface wind observations. Preprints, 15 International Conference on Interactive Information and Processing Systems for Meteorology, Oceanography, and Hydrology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 573-576 (1999).

No abstract.

Atlas, D., C.W. Ulbrich, F.D. Marks, E. Amitai, and C.R. Williams. Systematic variation of drop size and radar-rainfall relations. Journal of Geophysical Research, 104(D6):6155-6169 (1999).

Time histories of the characteristics of the drop size distribution of surface disdrometer measurements collected at Kapingamarangi Atoll were partitioned for several storms using rain rate, R, reflectivity factor Z, and median diameter of the distribution of water content D₀. This partitioning produced physically based systematic variations of the drop size distribution (DSD) and Z-R relations in accord with the precipitation types viewed simultaneously by a collocated radar wind profiler. These variations encompass the complete range of scatter around the mean Z-R relations previously reported by Tokay and Short (1996) for convective and stratiform rain and demonstrate that the scatter is not random. The systematic time or space variations are also consistent with the structure of mesoscale convective complexes with a sequence of convective, transition, and stratiform rain described by various authors. There is a distinct inverse relation between the coefficient A and the exponent of the Z-R relations which has been obscured in prior work because of the lack of proper discrimination of the rain types. Contrary to previous practice, it is evident that there is also a distinct difference in the DSD and the Z-R relations between the initial convective and the trailing transition zones. The previously reported Z-R relation for convective rain is primarily representative of the transition rain that was included in the convective class. The failure of present algorithms to distinguish between the initial convective and the trailing transition rains causes an erroneous apportionment of the diabatic heating and cooling and defeats the primary intent of discriminating stratiform from convective rains.

Baringer, M.O., and R.L. Molinari. Atlantic Ocean baroclinic heat flux at 24-26°N. Geophysical Research Letters, 26(3):353-356 (1999).

The spatially varying, interior geostrophic baroclinic heat flux component of the total meridional oceanic heat flux near 24°N in the Atlantic Ocean is examined using four transatlantic hydrographic sections including the October 1957 Discovery II IGY section, the September 1981 Atlantis section, the August 1992 Hesperides section, t he February 1998 Ronald H. Brown section and the 1982 Levitus and the Lozier, Owens, Curry climatologies. The 1992 section is complemented by shorter western boundary sections obtained concurrently during the Trident cruise. We find an average southward baroclinic heat flux of 0.9 0.3 PW with an annual cycle amplitude of 0.3 PW. More than 90% of the annual cycle is captured within 30° of the western boundary.

Baringer, M.O., and J.F. Price. A review of the physical oceanography of the Mediterranean Outflow. Marine Geology, 155(1-2):63-82 (1999).

The physical oceanography of the Mediterranean Sea is reviewed with particular emphasis on the Mediterranean outflow in the Gulf of Cadiz. In this region the dense Mediterranean water forms a high velocity bottom current that interacts strongly with the sea floor. The major energy source for the plume comes from the release of potential energy as the plume descends the continental slope, and the major energy sink is work against bottom stress, which is as large as 4 Pa where the plume begins to descend the continental slope. In this region the current makes a nearly inertial turn that would otherwise appear to be steered by the underlying topography. The Mediterranean plume entrains the overlying North Atlantic Central Water and thereby loses much of its density anomaly. The mixed Mediterranean water becomes neutrally buoyant in the lower portion of the North Atlantic thermocline near Cape St. Vincent. There are then two preferred transport modes having somewhat different temperature and salinity whose distinct characteristics can be found far into the open North Atlantic. The temperature, salinity and volume of the Mediterranean water in the Strait of Gibraltar and in the Gulf of Cadiz appear to be roughly constant since modern measurements have been made. The estimated westward transport of Mediterranean water has gone down considerably as direct measurement techniques have been applied. A recent estimate is that the westward transport of pure Mediterranean water is only about a half a Sv (1 Sv = 10⁶ m³/s); the transport of mixed Mediterranean water in the western Gulf of Cadiz is larger by about a factor of three or four because of the entrainment of North Atlantic water.

Bentamy, A.P., P. Queffeulou, Y. Quilfen, and K.B. Katsaros. Ocean surface wind fields estimated from satellite active and passive microwave instruments. IEEE Transactions on Geoscience and Remote Sensing, 37(5):2469-2486 (1999).

This study examines the consistency of surface wind speeds estimated from the European Remote Sensing Satellite (ERS-1) scatterometer, ERS-1 altimeter, and the special sensor microwave/imager (SSM/I). The goal is to combine these wind estimates to produce surface wind fields. With this in mind, a comparison with buoy wind measurements and comparison among the three sensors is performed. According to the in-situ data, the rms errors of the three wind estimates are all within 2 m/s. The differences between the remotely-sensed and buoy wind speeds are studied according to atmospheric and oceanic variables, and their impact is shown. A large data base is obtained from the comparisons among the three sensor winds. The rms values of the differences between the scatterometer and the altimeter and between the scatterometer and the SSM/I are 1.67 and 1.45 m/s, respectively. There is no global bias between the scatterometer and the SSM/I, but between the scatterometer and the altimeter wind speeds, the bias is about 0.3 m/s. Furthermore, it is shown that the difference between the scatterometer and the altimeter wind estimates is dependent on the significant wave height, while the difference between the scatterometer and the SSM/I winds is dependent on the integrated water vapor content. The comparison enables some corrections to be made for consistency and combining products. The use of combining scatterometer, altimeter, and SSM/I wind estimates is illustrated by two examples.

Berberian, G.A., and A.Y. Cantillo. Oceanographic conditions in the Gulf of Mexico and Straits of Florida: Fall 1976. NOAA Data Report, OAR AOML-36 (PB2000-106209), 64 pp. (1999).

NOAA conducted an investigation in the Gulf of Mexico and the Straits of Florida of oceanographic conditions and nutrients and trace metal levels in seawater during September and October 1976 aboard the NOAA Ship Researcher. This report lists the chemical data obtained from 118 stations. Collection and analyses methodologies, as well as results, are described.

Bishop, C.H., S. Majumdar, I. Szunyogh, Z. Toth, and S.D. Aberson. Using ensembles to simulate the impact of targeted observations. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 117-118 (1999).

No abstract.

Black, M.L. Recent observations of the hurricane eyewall: Unusual and complex structure. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 313-316 (1999).

No abstract.

Black, M.L., and J.L. Franklin. Recent observations of the convective structure associated with low-level wind maxima in the hurricane eyewall. Preprints, 29th International Conference on Radar Meteorology, Montreal, Quebec, Canada, July 12-16, 1999. American Meteorological Society, Boston, 370-373 (1999).

No abstract.

Black, R.A., and J. Hallett. Electrification of the hurricane. Journal of the Atmospheric Sciences, 56(12):2004-2028 (1999).

A survey of reports of electrical activity in hurricanes and typhoons from flight notes and personal experience (18 years, >230 eyewall penetrations for R. A. Black; ~20 years for J. Hallett, plus that of others at the Hurricane Research Division), and perusal of flight notes dating from 1980, show that lightning in and within 100 km or so of the eyewall is usually sparse. However, occasionally, significant electrical activity (>one flash per minute) occurs in or near the eyewall. National Oceanic and Atmospheric Administration WP-3D aircraft penetrations through a number of storms relate the lightning occurrence to strong vertical velocity (>10 m s^-1) and the presence of supercooled liquid cloud droplets extending to temperatures below 20°C. Specific measurements of cloud properties during eyewall penetrations show that the supercooled cloud water content increases with upward velocities > ~5.0 m s^-1, as does the presence of large (>2 mm) supercooled drops. Measurements at temperatures >-13°C show that the transition of supercooled cloud water to ice along an outward radial in all systems is associated with local electric fields (occasionally >20 kV m^-1) and negative charge above positive charge. In systems with stronger vertical velocity there is a larger region of supercooled cloud extending to lower temperatures where charge separation may occur, as judged by the presence of regions containing graupel, small ice, and cloud droplets. The ratio of ice to supercooled water increases radially outward from the eyewall and depends upon altitude (temperature). The spatial distribution of charge is further influenced by the relation of vertical velocity to the radial flow, with the upper charge regions tending to be advected outward. In symmetrical, mature hurricanes, supercooled water usually occurs only in regions at temperatures above about -5°C. The upward transport of supercooled cloud water is limited by a balance between water condensed in the eyewall updraft and its erosion by ice in downdrafts descending in the outward regions of the eyewall. This ice originates from both primary and secondary ice nucleation in the updraft. This is consistent with an exponential increase in ice concentration, as the rate at which the ice particle concentrations increase depends on the production of secondary particles by preexisting graupel, some of which ultimately grow into new graupel, and its outward transport in the anvil flow aloft. Penetrations at temperatures as low as -15°C show the presence of electric fields consistent with specific laboratory-derived criteria for charge separated during ice-graupel collisions, given that a liquid water-dependent sign reversal temperature may occur. Such a reversal may result from either a changing temperature in the vertical, a changing cloud liquid water content in the horizontal, or a combination of the two. Since cloud-to-ground (CG) lightning can be observed with remote detection networks that provide the polarity and frequency of CG lightning, there is potential that hurricane evolution may be detected remotely and that lightning may be usable as an indicator of a change in the storm intensity and/or track.

Boebel, O., C. Schmid, and W. Zenk. Kinematic elements of Antarctic Intermediate Water in the western South Atlantic. Deep-Sea Research, Part II, 46(1-2):355-392 (1999).

The northward flowing Antarctic Intermediate Water (AAIW) is a major contributor to the large-scale meridional circulation of water masses in the Atlantic. Together with bottom and thermocline water, AAIW replaces North Atlantic Deep Water that penetrates into the South Atlantic from the north. On the northbound propagation of AAIW from its formation area in the southwestern region of the Argentine Basin, the AAIW progresses through a complex spreading pattern at the base of the main thermocline. This paper presents trajectories of 75 subsurface floats, seeded at AAIW depth. The floats were acoustically tracked, covering a period from December 1992 to October 1996. Discussions of selected trajectories focus on mesoscale kinematic elements that contribute to the spreading of AAIW. In the equatorial region, intermittent westward and eastward currents were observed, suggesting a seasonal cycle of the AAIW flow direction. At tropical latitudes, just offshore the intermediate western boundary current, the southward advection of an anticyclonic eddy was observed between 5°S and 11°S. Farther offshore, the flow lacks an advective pattern and is governed by eddy diffusion. The westward subtropical gyre return current at about 28°S shows considerable stability with the mean kinetic energy to eddy kinetic energy ratio being around one. Farther south, the eastward deeper South Atlantic Current is dominated by large-scale meanders with particle velocities in excess of 60 cm s^-1. At the Brazil-Falkland Current Confluence Zone, a cyclonic eddy near 40°S, 50°W seems to act as injector of freshly mixed AAIW into the subtropical gyre. In general, much of the mixing of the various blends of AAIW is due to the activity of mesoscale eddies, which frequently reoccupy similar positions.

Boebel O., C. Schmid, G. Podesta, and W. Zenk. Intermediate water in the Brazil-Malvinas Confluence Zone: A Lagrangian view. Journal of Geophysical Research, 104(C9):21,063-21,082 (1999).

The subsurface flow within the subantarctic and subtropical regions around the Brazil-Malvinas Confluence Zone is studied, using daily hydrographic and kinematic data from four subsurface floats and a hydrographic section parallel to the South American shelf. The trajectories are mapped against sea-surface flow patterns as visible in concurrent satellite sea-surface temperature images, with focus on the November 1994 and October/November periods. The unprecedented employment of Lagrangian-S diagrams enables us to trace the advection of patches of fresh Antarctic Intermediate Water (AAIW) from the Confluence Zone into the subtropical region. The fresh AAIW consists of a mixture of subtropical AAIW and Malvinas Current core water. Within the subtropical gyre, these patches are discernible for extended periods and drift over long distances, reaching north to 34.26°S and east to 40.26°W. The cross-frontal migration of quasi-isobaric floats across the Confluence Zone from the subtropical to the subantarctic environment is observed on three occasions. The reverse process, float migration from a subpolar to a subtropical environment was observed once. These events were located near 40.26°S, 50.26°W, the site of a reoccurring cold core feature. Subsurface float and SST data comparison reveals similarities with analogous observations made in the Gulf Stream (Rossby, 1996) where cross-frontal processes were observed close to meander crests. The limited number of floats of this study and the complex structure of the Brazil-Malvinas Confluence Zone, however, restricts the analysis to a description of two events.

Boebel, O., R.E. Davis, M. Ollitrault, R.G. Peterson, P.L. Richardson, C. Schmid, and W. Zenk. Direct observations of the western South Atlantic intermediate depth circulation. Geophysical Research Letters, 26(21):3329-3332 (1999).

The subsurface oceanic circulation is an important part of the Earth climate system. Subsurface currents traditionally are inferred indirectly from distributions of temperature and dissolved substances, occasionally supplemented by current meter measurements. Neutrally-buoyant floats, however, now enable us to obtain for the first time directly measured intermediate depth velocity fields over large areas such as the western South Atlantic. Here, our combined data set provides unprecedented observations and quantification of key flow patterns, such as the Subtropical Gyre return flow (12 Sv; 1 Sverdrup = 10⁶ m³ s^-1), its bifurcation near the Santos Plateau and the resulting continuous narrow and swift northward intermediate western boundary current (4 Sv). This northward flowing water passes through complex equatorial flows and finally enters into the North Atlantic.

Bosart, L.F., W.E. Bracken, J. Molinari, C.S. Velden, and P.G. Black. Environmental influences on the rapid intensification of Hurricane Opal (1995) over the Gulf of Mexico. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 983-984 (1999).

No abstract.

Bourles, B., R.L. Molinari, E. Johns, W.D. Wilson, and K.D. Leaman. Upper layer currents in the western tropical North Atlantic (1989-1991). Journal of Geophysical Research, 104(C1):1361-1376 (1999).

Shipboard Acoustic Doppler Current Profiler (ADCP) measurements and hydrographic observations of temperature, salinity, and dissolved oxygen are used to examine the upper water column flow field in the North Brazil Current (NBC) retroflection region of the western tropical Atlantic Ocean. Observations are presented from six cruises, one conducted in August 1989 and the other five conducted during the Western Tropical Atlantic Experiment (WESTRAX) between January 1990 and September 1991. The upper water column is divided into two layers, an upper thermocline layer located between the surface and the 24.5 sigma theta isopycnal surface, and a lower subthermocline layer located between the 24.5 and 26.75 isopycnals. In the upper layer the NBC retroflects north of the equator to form the eastward flowing North Equatorial Counter Current (NECC). During the six cruises the retroflection appeared complete. However, data coverage did not extend shoreward of the 200 m isobath, so the possibility of a continuous flow over the shelf still remains. There were also indications of several NBC rings which had apparently separated from the NBC retroflection and drifted to the northwest towards the eastern Caribbean Sea. North of the NBC retroflection and the NECC, the North Equatorial Current (NEC) flows west as the southern limb of the subtropical gyre. Part of the NEC is observed to retroflect cyclonically to join the eastward NECC flow. In the lower layer, beneath the NBC, the North Brazil Undercurrent (NBUC) retroflects to feed the eastward North Equatorial Undercurrent (NEUC). To the north, a deeper component of the NEC recurves to also contribute to the NEUC.

Boutin, J., J. Etcheto, Y. Dandonneau, D.C.E. Bakker, R.A. Feely, H.Y. Inoue, M. Ishii, R.D. Ling, P.D. Nightingale, N. Metzl, and R.H. Wanninkhof. Satellite sea surface temperature: A powerful tool for interpreting in-situ pCO₂ measurements in the equatorial Pacific Ocean. Tellus B, 51(2):490-508 (1999).

In order to determine the seasonal and interannual variability of the CO₂ released to the atmosphere from the equatorial Pacific, we have developed pCO₂-temperature relationships based upon shipboard oceanic CO₂ partial pressure measurements, pCO₂, and satellite sea surface temperature, SST, measurements. We interpret the spatial variability in pCO₂ with the help of the SST imagery. In the eastern equatorial Pacific, at 5°S, pCO₂ variations of up to 100 µatm are caused by undulations in the southern boundary of the equatorial upwelled waters. These undulations appear to be periodic with a phase and a wavelength comparable to tropical instability waves, TIW, observed at the northern boundary of the equatorial upwelling. Once the pCO₂ signature of the TIW is removed from the Alize II cruise measurements in January 1991, the equatorial pCO₂ data exhibit a diel cycle of about 10 µatm with maximum values occurring at night. In the western equatorial Pacific, the variability in pCO₂ is primarily governed by the displacement of the boundary between warm pool waters, where air-sea CO₂ fluxes are weak, and equatorial upwelled waters which release high CO₂ fluxes to the atmosphere. We detect this boundary using satellite SST maps. East of the warm pool, DELTA-P is related to SST and SST anomalies. The 1985-1997 CO₂ flux is computed in a 5° wide latitudinal band as a combination of DELTA-P and CO₂ exchange coefficient, K, deduced from satellite wind speed, U. It exhibits up to a factor 2 seasonal variation caused by K-seasonal variation and a large interannual variability, a factor 5 variation between 1987 and 1988. The interannual variability is primarily driven by displacements of the warm pool that makes the surface area of the outgassing region variable. The contribution of DELTA-P to the flux variability is about half of the contribution of K. The mean CO₂ flux computed using either the Liss and Merlivat (1986) or the Wanninkhof (1992) K-U parameterization amounts to 0.11 GtC yr^-1 or to 0.18 GtC yr^-1, respectively. The error in the integrated flux, without taking into account the uncertainly on the K-U parameterization, is less than 31%.

Bove, M.C., J.B. Elsner, C.W. Landsea, X. Niu, and J.J. O'Brien. Effect of El Ni�o on U.S. landfalling hurricanes, revisited. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 278-281 (1999).

No abstract.

Broecker, W.S., S. Sutherland, and T.-H. Peng. A possible 20th-century slowdown of Southern Ocean deep water formation. Science, 286(5442):1132-1135 (1999).

Chlorofluorocarbon-11 inventories for the deep Southern Ocean appear to confirm physical oceanographic and geochemical studies in the Southern Ocean, which suggests that no more than 5 × 10⁶ cubic meters per second of ventilated deep water is currently being produced. This result conflicts with conclusions based on the distributions of the carbon-14/carbon ratio and a quasi-conservative property, PO₄, in the deep sea, which seem to require an average of about 15 × 10⁶ cubic meters per second of Southern Ocean deep ventilation over about the past 800 years. A major reduction in Southern Ocean deep water production during the 20th century (from high rates during the Little Ice Age) may explain this apparent discordance. If this is true, a seesawing of deep water production between the northern Atlantic and Southern Oceans may lie at the heart of the 1500-year ice-rafting cycle.

Broecker, W.S., E. Clark, D.C. McCorkle, T.-H. Peng, I. Hajdas, and G. Bonani. Evidence for a reduction in the carbonate ion content of the deep sea during the course of the Holocene. Paleoceanography, 14(6):744-752 (1999).

The paleo carbonate ion proxy proposed by Broecker et al. (1999) is applied in a search for trends in the Holocene acidity of waters in the transition zone between North Atlantic Deep Water (NADW) and Antarctic Bottom Water (AABW). A clear signal emerges that the carbonate ion content of waters in this zone declined during the last 8000 years. In order to determine whether this decline represents a strengthening of the northward penetrating tongue of low CO₃ content AABW or a global reduction of CO₃ ion, measurements were made on a core from the Ontong Java Plateau in the western equatorial Pacific. Evidence for a similar decline in CO₃ ion over the course of the Holocene was obtained, lending support of the latter explanation. Such a drop is consistent with the recent finding by Indermuhle et al. (1999) that the CO₂ content of the atmosphere (as recorded in the Taylor Dome Antarctica ice core) rose by 20 to 25 ppm during the last 8000 years.

Campos, E., A. Busalacchi, S.L. Garzoli, J. Lutjeharms, R. Matano, P. Nobre, D.B. Olson, A. Piola, C. Tanajura, and I. Wainer. The South Atlantic and the climate. OCEANOBS99: International Conference on the Ocean Observing System for Climate, Saint Raphael, France, October 18-22, 1999. Centre National d'Etudes Spatiales, Vol. 1, 16 pp. (1999).

As a contribution to the OCEANOBS99 objectives, we give a brief description of the present knowledge of the South Atlantic and identify some key processes and areas which need to be monitored in order to understand the role of that part of the ocean in the global climate. Included are suggestions of strategies for a first approximation towards an ocean climate monitoring system in the South Atlantic.

Checkley, D.M., P.B. Ortner, F.E. Werner, L.R. Settle, and S.R. Cummings. Spawning habitat of the Atlantic menhaden in Onslow Bay, North Carolina. Fisheries Oceanography, 8(2):22-36 (1999).

The Continuous, Underway Fish Egg Sampler (CUFES) was used to sample pelagic eggs of the Atlantic menhaden (Brevoortia tyrannus) from a 3-m depth off North Carolina in winter 1993-1994 and 1994-1995. Simultaneous measurements were made of temperature, salinity, and the concentration of chlorophyll a. The maximal concentration of eggs was 346 eggs m^-3. Eggs were highly aggregated in patches which occurred between the Gulf Stream and mid-shelf fronts (17-23°C, 36.0-36.4 ppm). Unexpectedly, eggs were found almost exclusively in water of 20-60 m (mode 20 m) bottom depth. Thus, spawning appears related to bathymetry as well as hydrography. Variograms for egg concentration indicated a mean (± SE) patch scale of 3.6 ± 1.7 km and a high degree of spatial variance explained by CUFES sampling. Lagrangian modeling of particles moving in response to tides, winds, and a prescribed flow from the north indicated that the region of observed, maximal occurrence of eggs is favorable for the retention of eggs and larvae on the shelf adjacent to inlets used to enter nursery areas.

Cione, J.J., P.G. Black, and S.H. Houston. Cooling and drying within the hurricane near-surface environment? Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 1027-1030 (1999).

No abstract.

DeMaria, M., and J. Kaplan. An updated Statistical Hurricane Intensity Prediction Scheme (SHIPS) for the Atlantic and eastern North Pacific basins. Weather and Forecasting, 14(3):326-337 (1999).

Updates to the Statistical Hurricane Intensity Prediction Scheme (SHIPS) for the Atlantic basin are described. SHIPS combines climatological, persistence, and synoptic predictors to forecast intensity changes using a multiple regression technique. The original version of the model was developed for the Atlantic basin and was run in near-real time at the Hurricane Research Division beginning in 1993. In 1996, the model was incorporated into the National Hurricane Center operational forecast cycle, and a version was developed for the eastern North Pacific basin. Analysis of the forecast errors for the period 1993-1996 shows that SHIPS had little skill relative to forecasts based upon climatology and persistence. However, SHIPS had significant skill in both the Atlantic and east Pacific basins during the 1997 hurricane season. The regression coefficients for SHIPS were rederived after each hurricane season since 1993 so that the previous season's forecast cases were included in the sample. Modifications to the model itself were also made after each season. Prior to the 1997 season, the synoptic predictors were determined only from an analysis at the beginning of the forecast period. Thus, SHIPS could be considered a "statistical-synoptic" model. For the 1997 season, methods were developed to remove the tropical cyclone circulation from the global model analyses and to include synoptic predictors from forecast fields, so the current version of SHIPS is a "statistical-dynamical" model. It was only after the modifications for 1997 that the model showed significant intensity forecast skill.

Dickerson, R.R., K.P. Rhoads, T.P. Carsey, S.J. Oltmans, J.P. Burrows, and P.J. Crutzen. Ozone in the remote marine boundary layer: A possible role for halogens. Journal of Geophysical Research, 104(D17):21,385-21,395 (1999).

On the spring 1995 cruise of the National Oceanic and Atmospheric Administration research vessel Malcolm Baldrige, we measured very large diurnal variations in ozone concentrations in the marine boundary layer. Average diurnal variations of about 32% of the mean were observed over the tropical Indian Ocean. We simulated these observations with the Model of Chemistry in Clouds and Aerosols, a photochemical box model with detailed aerosol chemistry. The model was constrained with photolysis rates, humidity, aerosol concentrations, NO, CO, and O₃ specified by shipboard observations and ozonesondes. Conventional homogeneous chemistry, where ozone photolysis to O(¹D) and HO_x chemistry dominate ozone destruction, can account for a diurnal variation of only about 12%. On wet sea-salt aerosols (at humidities above the deliquesence point), absorption of HOBr leads to release of BrCl and Br₂, which photolyze to produce Br atoms that may provide an additional photochemical ozone sink. After eight days of simulation, these Br atoms reach a peak concentration of 1.2 × 10⁷ cm^-3 at noon and destroy ozone through a catalytic cycle involving BrO and HOBr. Reactive Br lost to HBr can be absorbed into the aerosol phase and reactivated. The model predicts a diurnal variation in O₃ of 22% with aerosol-derived Br reaction explaining much, but not all, of the observed photochemical loss. The lifetime of ozone under these conditions is short, about two days. These results indicate that halogens play an important role in oxidation processes and the ozone budget in parts of the remote marine boundary layer.

Digby, S., T. Antczak, R. Leben, G. Born, S. Barth, R. Cheney, D. Foley, G.J. Goni, G. Jacobs, and L. Shay. Altimeter data for operational use in the marine environment. Proceedings, Oceans '99 MTS/IEEE Conference, Seattle, WA, September 13-16, 1999. Marine Technology Society, 605-613 (1999).

TOPEX/Poseidon has been collecting altimeter data continuously since October 1992. Altimeter data have been used to produce maps of sea surface height, geostrophic velocity, significant wave height, and wind speed. This information is of proven use to mariners as well as to the scientific community. Uses of the data include commercial and recreational vessel routing, ocean acoustics, input to geographic information systems developed for the fishing industry, identification of marine mammal habitats, fisheries management, and monitoring ocean debris. As with sea surface temperature data from the Advanced Very High Resolution Radiometer (AVHRR) in the late 1980s and early 1990s, altimeter data from TOPEX/Poseidon and ERS-1 and -2 are in the process of being introduced to the marine world for operational maritime use. It is anticipated that over the next few years companies that specialize in producing custom products for shipping agencies, fisheries, and yacht race competitors will be incorporating altimeter data into their products. The data are also being incorporated into weather and climate forecasts by operational agencies both in the United States and Europe. This paper will discuss these products, their uses, operational demonstrations, and means of accessing the data.

Dodge, P.P., R.W. Burpee, and F.D. Marks. The kinematic structure of a hurricane with sea-level pressure less than 900 mb. Monthly Weather Review, 127(6):987-1004 (1999).

A National Oceanic and Atmospheric Administration aircraft recorded the first Doppler radar data in a tropical cyclone with a minimum sea level pressure (MSLP) <900 mb during a reconnaissance mission in Hurricane Gilbert on 14 September 1988, when its MSLP was ~895 mb. A previous mission had found an MSLP of 888 mb, making Gilbert the most intense tropical cyclone yet observed in the Atlantic basin. Radar reflectivity identified the hurricane eye, inner and outer eyewalls, a stratiform region between the eyewalls, and an area outside the outer eyewall that contained a few rainbands but that had mostly stratiform rain. Pseudo-dual Doppler analyses depict the three-dimensional kinematic structure of the inner eyewall and a portion of the outer eyewall. The vertical profiles of tangential wind and reflectivity maxima in the inner eyewall are more erect than in weaker storms, and winds >50 m s^-1 extended to 12 km, higher than has been reported in previous hurricanes. The inner eyewall contained weak inflow throughout most of its depth. In contrast, the portion of the outer eyewall described here had shallow inflow and a broad region of outflow. The stratiform region between the two eyewalls had lower reflectivities and was the only region where the vertically incident Doppler radar data seemed to show downward motion below the freezing level. Gilbert's structure is compared with other intense Atlantic and eastern North Pacific hurricanes with MSLP >900 mb. Storms with lower MSLP have higher wind speeds in both inner and outer eyewalls, and wind speeds >50 m s^-1 extend higher in storms with lower MSLP. Hurricanes Gilbert and Gloria (1985), the strongest Atlantic hurricanes yet analyzed by the Hurricane Research Division, had different outer eyewall structures. Gloria's outer eyewall had a deep region of inflow, while Gilbert's inflow layer was shallow. This may explain differences in the subsequent evolution of the two storms.

Dodge, P.P., J.F. Gamache, S.H. Houston, and F.D. Marks. Windfields in landfalling hurricanes from multiple Doppler radar data: The 1998 hurricane season. Preprints, 29th International Conference on Radar Meteorology, Montreal, Quebec, Canada, July 12-16, 1999. American Meteorological Society, Boston, 273-275 (1999).

No abstract.

Dodge, P.P., S.H. Houston, W.-C. Lee, J.F. Gamache, and F.D. Marks. Windfields in Hurricane Danny (1997) at landfall from combined WSR-88D and airborne Doppler radar data. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 61-62 (1999).

No abstract.

Donnelly, W.J., J.R. Carswell, R.E. McIntosh, P.S. Chang, J.C. Wilkerson, F.D. Marks, and P.G. Black. Revised ocean backscatter models at C and Ku-bands under high wind conditions. Journal of Geophysical Research, 104(C5):11,485-11,498 (1999).

A series of airborne scatterometer experiments designed to collect C and Ku-band ocean backscatter data in regions of high ocean surface winds has recently been completed. Over 100 hours of data were collected using the University of Massachusetts C and Ku-band scatterometers, CSCAT and KUSCAT. These instruments measure the full azimuthal normalized radar cross section (NRCS) of a common surface area of the ocean simultaneously at four incidence angles. Our results demonstrate limitations of the current empirical models, CMOD4, SASSII and NSCAT1, that relate ocean backscatter to the near surface wind at high wind speeds. The discussion focuses on winds in excess of 15 m/sec in clear atmospheric conditions. The scatterometer data is collocated with measurements from ocean data buoys and GPS dropsondes, and a Fourier analysis is performed as a function of wind regime. A three-term Fourier series is fit to the backscatter data, and a revised set of coefficients is tabulated. These revised models, CMOD4HW and KUSCAT1, are the basis for a discussion of the NRCS at high wind speeds. Our scatterometer data show a clear over prediction of the derived NRCS response to high winds based on the CMOD4, SASSII and NSCAT1 models. Furthermore, saturation of the NRCS response begins to occur above 15 m/sec. Sensitivity of the upwind and crosswind response is discussed with implications towards high wind speed retrieval. wind speed retrieval.

Ellsberry, R.L., and F.D. Marks. The Hurricane Landfall Workshop summary. Bulletin of the American Meteorological Society, 80(4):683-685 (1999).

No abstract.

Enfield, D.B., and E.J. Alfaro. The dependence of Caribbean rainfall on the interaction of tropical Atlantic and Pacific Oceans. Journal of Climate, 12(7):2093-2103 (1999).

Seasonally-stratified analyses of rainfall anomalies over the Intra-Americas Sea and surrounding land areas and of onset and end dates of the Central American rainy season show that the variability of the tropical Atlantic sea surface temperature anomaly (SSTA) is more strongly associated with rainfall over the Caribbean and Central America than is tropical eastern Pacific SSTA. Seasonal differences include the importance of antisymmetric configurations of tropical Atlantic SSTA in the dry season but not in the rainy season. Both oceans are related to rainfall, but the strength of the rainfall response appears to depend on how SSTA in the tropical Atlantic and eastern Pacific combine. The strongest response occurs when the tropical Atlantic is in the configuration of a meridional dipole (antisymmetric across the ITCZ) and configuration of a meridional dipole (antisymmetric across the ITCZ) and the eastern tropical Pacific is of opposite sign to the tropical North Atlantic. When the tropical North Atlantic and tropical Pacific are of the same sign, the rainfall response is weaker. The rainy season in lower Central America tends to start early and end late in years that begin with warm SSTs in the tropical North Atlantic, and the end dates are also delayed when the eastern equatorial Pacific is cool. This enhancement of date departures for zonally antisymmetric configurations of SSTA between the North Atlantic and Pacific is qualitatively consistent with the results for rainfall anomalies.

Enfield, D.B., and A.M. Mestas-Nunez. Multiscale variabilities in global sea surface temperatures and their relationships with tropospheric climate patterns. Journal of Climate, 12(9):2719-2733 (1999).

El Niño-Southern Oscillation (ENSO) is a global phenomenon with significant phase propagation within and between basins. We capture and describe this in the first mode of a complex empirical orthogonal function (CEOF) analysis of sea surface temperature anomaly (SSTA) from the mid-19th century through 1991. We subsequently remove the global ENSO from the SSTA data, plus a linear trend everywhere, in order to consider other global modes of variability uncontaminated by the intra- and inter-basin effects of ENSO. An ordinary EOF analysis of the SSTA residuals reveals three non-ENSO modes of low-frequency variability that are related to slow oceanic and climate signals described in the literature. The first two modes have decadal-to-multidecadal time scales with high loadings in the Pacific. They bear some spatial similarities to the ENSO pattern but are broader, more intense at high latitudes, and differ in the time domain. A CEOF analysis confirms that they are not merely the phase-related components of a single mode and that all three modes are without significant phase propagation. The third mode is a multidecadal signal with maximal realization in the extratropical North Atlantic southeast of Greenland. It is consistent with studies that have documented connections between North Atlantic SSTA and the tropospheric North Atlantic Oscillation (NAO). All three SSTA modes have mid-tropospheric associations related to previously classified Northern Hemisphere teleconnection patterns. The relationships between SSTA modes and tropospheric patterns are consistent with the ocean-atmosphere interactions discussed in previous studies to explain low-frequency climate oscillations in the North Pacific and North Atlantic sectors. The first three leading modes of non-ENSO SSTA are most related, respectively, to the tropospheric patterns of the Pacific North American (PNA), the North Pacific (NP) and the Arctic Oscillations (AO), respectively. The 500 hPa pattern associated with the third SSTA mode also bears similarities to the NAO in its Atlantic sector. This North Atlantic mode has a region of high, positive SSTA loadings in the Gulf of Alaska, which appear to be connected to the North Atlantic SSTA by a tropospheric bridge effect in the AO.

Enfield, D.B., A.M. Mestas-Nunez, D.A. Mayer, and L. Cid-Serrano. How ubiquitous is the dipole relationship in tropical Atlantic sea surface temperatures? Journal of Geophysical Research, 104(C4):7841-7848 (1999).

Several kinds of analysis are applied to the departures of sea surface temperatures from climatology (SSTA, 1856-1991) to determine the degree to which SSTA of opposite sign in the tropical North and South Atlantic occur. Antisymmetric ("dipole") configurations of SSTA on basin scales are not ubiquitous in the tropical Atlantic. Unless the data are stratified by both season and frequency, inherent dipole behavior cannot be demonstrated. Upon removing the global ENSO signal in SSTA (which is symmetric between the North and South Atlantic) from the data, the regions north or south of the intertropical convergence zone have qualitatively different temporal variabilities and are poorly correlated. Dipole configurations do occur infrequently (12-15% of the time), but no more so than expected by chance for stochastically-independent variables. Non-dipole configurations that imply significant meridional SSTA gradients occur much more frequently, nearly half of the time. Cross-spectral analysis of seasonally averaged SSTA indices for the North and South Atlantic show marginally significant coherence with antisymmetric phase in two period bands: 8-12 years for the boreal winter-spring, and 2.3 years for the boreal summer-fall. Antisymmetric coherence is optimal for a small sub-region west of Angola in the South Atlantic, with respect to SSTA of basin scale in the tropical North Atlantic. Dipole variability, even where optimal, explains only a small fraction of the total variance in tropical Atlantic SSTA (<7%).

Enfield, D.B., A.M. Mestas-Nunez, D.A. Mayer, and L. Cid-Serrano. The dipole in tropical Atlantic SST: Common? Random? Intrinsic? Proceedings, 23rd Annual Climate Diagnostics and Prediction Workshop, Miami, Florida, October 26-30, 1998. National Weather Service, 223-226 (1999).

In this paper we clarify the confusing and apparently contradictory views regarding tropical Atlantic dipole variability. The issue is revisited by using a recently reconstructed 136-year SST anomaly (SSTA) analysis for the globe (Kaplan et al., 1998; henceforth, K98). An expanded analysis will appear in the Journal of Geophysical Research-Oceans (Enfield et al., 1999).

Esenkov, O.E., and B. Cushman-Roisin. Modeling of two-layer eddies and coastal flows with a particle method. Journal of Geophysical Research, 104(C5):10,959-10,980 (1999).

An existing particle-in-cell (PIC) numerical code is applied to lens-like anticyclonic vortices and buoyant coastal currents. A first series of experiments with initially elongated eddies reveals that motions induced in the lower layer act to increase the rate of rotation of the structure; eccentricity reduction, if any, produces a final vortex of aspect ratio between 1.8 and 1.9, in accordance with a theoretical prediction. A second series of experiments determines the maximal separation distance that can exist between two identical and circular vortices before they spontaneously merge; this distance is a function of the vortex size and ambient stratification. In a third series of experiments, vortex interactions across layers are considered; results similar to those obtained with two-layer point vortices (hetons) are obtained. Finally, the PIC method is generalized to simulate the finite-amplitude instability of a buoyant geostrophic current flowing along a vertical coastal wall.

Etcheto, J., J. Boutin, Y. Dandonneau, D.C.E. Bakker, R.A. Feely, R.D. Ling, P.D. Nightingale, and R.H. Wanninkhof. Air-sea CO₂ flux variability in the equatorial Pacific Ocean near 100°W. Tellus B, 51(3):734-747 (1999).

The interannual variability of the CO₂ partial pressure (pCO₂) in the surface layer of the east equatorial Pacific Ocean near 100°W is studied and compared with the sea surface temperature (SST) monitored from satellites. This variability is shown to be correlated with the SST anomaly rather than with the temperature itself. The pCO_2OC variability is related to the variability of the upwelling systems (the equatorial upwelling and the upwelling along the American coast), the main influence being from the coastal upwelling via the surface water advected from the east. A method is derived to interpolate the pCO_2OC measurements using the SST satellite measurements. By combining the result with the exchange coefficient (K) deduced from the wind speed provided by satellite-borne instruments, we deduce the air-sea CO₂ flux and, for the first time, we continuously monitor its temporal variation. The variability of this flux is mainly due to the variability of K, with a clear seasonal variation. The flux obtained using the Liss and Merlivat (1986) relationship averaged from April 1985 to June 1997 in the region 97.5°-107.5°W, 0-5°S is 1.67 mole m^-2 yr^-1 of CO₂, leaving the ocean with an estimated accuracy of 30%.

Etcheto, J., J. Boutin, D.C.E. Bakker, Y. Dandonneau, R.A. Feely, H.Y. Inoue, M. Ishii, R.D. Ling, L. Merlivat, P.D. Nightingale, N.Metzl, and R.H. Wanninkhof. pCO₂ in the equatorial Pacific and Atlantic Oceans: Determination of air-sea CO₂ flux using satellite-borne instruments. Proceedings, Second International Symposium on CO₂ in the Oceans, Tsukuba, Japan, January 18-22, 1999. Center for Global Environmental Research (CGER-I037-99), 119-125 (1999).

No abstract.

Feely, R.A., M.F. Lamb, D.J. Greeley, and R.H. Wanninkhof. Comparison of the carbon system parameters at the global CO₂ survey crossover locations in the North and South Pacific Ocean between 1990-1996. Technical Report, ORNL/CDIAC-115, Oak Ridge National Laboratory/Carbon Dioxide Information Analysis Center, 73 pp. (1999).

As a collaborative program to measure global ocean carbon inventories and provide estimates of the anthropogenic carbon dioxide (CO₂) uptake by the oceans, the National Oceanic and Atmospheric Administration and the U.S. Department of Energy have sponsored the collection of ocean carbon measurements as part of the World Ocean Circulation Experiment and Ocean-Atmosphere Carbon Exchange Study cruises. The cruises discussed here occurred in the North and South Pacific from 1990 through 1996. The carbon parameters from these 30 crossover locations have been compared to ensure a consistent global data set emerges from the survey cruises. The results indicate that for dissolved inorganic carbon, fugacity of CO₂, and pH, the agreement at most crossover locations are well within the design specifications for the global CO₂ survey, whereas in the case of total alkalinity, the agreement between crossover locations is not as close.

Feely, R.A., C.L. Sabine, R.M. Key, and T.-H. Peng. CO₂ survey synthesis results: Estimating the anthropogenic carbon dioxide sink in the Pacific Ocean. U.S. JGOFS News, 9(4):1-4 (1999).

Our results to date suggest that the cumulative amount of anthropogenic CO₂ in the global ocean is somewhere between 105 and 118 PgC through the year 1996. These results can be utilized as a constraint on other global carbon model simulations, similar to Princeton/Geophysical Fluid Dynamics Laboratory Ocean Biogeochemical Model and National Center for Atmospheric Research model simulations. As we refined and complete the estimates of the oceanic uptake of anthropogenic CO₂, the results will be compared to CO₂ uptake estimates for the atmosphere and terrestrial biosphere.

Feely, R.A., R.H. Wanninkhof, T. Takahashi, and P. Tans. Influence of El Ni�o on the equatorial Pacific contribution to atmospheric CO₂ accumulation. Nature, 398(6728):597-601 (1999).

The equatorial ocean is an important CO₂ source to the atmosphere, contributing annually 0.7-1.5 Pg of carbon as CO₂, as much as 80% of which is attributed to the equatorial Pacific. This source is known to change significantly by ENSO events. To better understand the regional and interannual variability of CO₂ fluxes from the equatorial Pacific, field measurements of the partial pressure of CO₂ (pCO₂) have been made in the equatorial Pacific region since 1992. Here, we report that during the 1991-1994 ENSO period the net annual sea-to-air flux of CO₂ was 0.3 PgC from the fall of 1991 to the fall of 1992, 0.6 PgC in 1993, and 0.7 PgC in 1994. These fluxes are 30%-80% of the 0.9 PgC observed during the non-El Ni�o year of 1996. The total reduction of the sea-to-air CO₂ flux during the 1991-1994 El Ni�o is estimated to be 0.8-1.2 PgC, which accounts for 16-36% of the atmospheric anomaly (the difference between the annual atmospheric CO₂ increase in PgC yr^-1 and the long-term average increase of 3.18 PgC yr^-1) observed over the same period.

Feely, R.A., C.L. Sabine, R.M. Key, T.-H. Peng, and R.H. Wanninkhof. The U.S. global CO₂ survey in the North and South Pacific Ocean. Preliminary synthesis results. Proceedings, Second International Symposium on CO₂ in the Oceans, Tsukuba, Japan, January 18-22, 1999. Center for Global Environmental Research (CGER-I037-99), 193-198 (1999).

As a collaborative program to measure global ocean carbon inventories and provide estimates of the anthropogenic CO₂ uptake in the oceans, the National Oceanic and Atmospheric Administration, the U.S. Department of Energy, and the National Science Foundation have co-sponsored the collection of ocean carbon measurements as part of the World Ocean Circulation Experiment (WOCE) and Ocean-Atmospheric Carbon Exchange Study (OACES). The cruises discussed here occurred in the North and South Pacific from 1990 through 1996. The new estimates for anthropogenic CO₂, employing the DELTA-C* method of Gruber et al. (1996), indicate that the largest buildup of anthropogenic CO₂ occurs in subtropical waters. Along 155°W, anthropogenic CO₂ penetrates to a maximum depth of 900 m at about 37°N in the North Pacific and 1300 m at about 48°S in the South Pacific. Strong shoaling of anthropogenic CO₂ occurs southward of 50°S and northward of 48°N. The anthropogenic CO₂ inventories from the observations are smaller than the Princeton Ocean Biogeochemical Model (POBM) model estimates, primarily because the Princeton model produces too much deep convective mixing of anthropogenic CO₂ in the Southern Ocean. The NCAR Climate System Ocean model, which has very different physics and biological parameterizations, appears to do a better job of reproducing the general patterns in the data-based section.

Fine, R.A., L. Merlivat, W. Roether, W.M. Smethie, and R.H. Wanninkhof. Observing tracers and the carbon cycle. OCEANOBS99: International Conference on the Ocean Observing System for Climate, Saint Raphael, France, October 18-22, 1999. Centre National d'Etudes Spatiales, Vol. 1, 14 pp. (1999).

A program for repeated sampling of tracers and variables essential for quantitative understanding of the carbon cycle is recommended within CLIVAR/GOOS. The program is critical to our monitoring and understanding of climate change, both natural and anthropogenic. The objectives are: quantification of changes in the rates and spatial patterns of oceanic carbon uptake, fluxes, and storage of anthropogenic CO₂; detection and possible quantification of changes in water mass renewal and mixing rates; and provision of a stringent test of the time integration of models' natural and anthropogenic climate variability. The strategy is to put in place a global observing network for tracers and CO₂ to document the continuing large-scale evolution of these fields. Hydrographic lines are advocated, although it is realized that there has to be a limit on these observations due to logistical and resource constraints. Thus, there is the need to supplement these observations with time series and autonomous measurements to provide detail in the temporal evolution of the fields.

Franklin, J.F., M.L. Black, and S.E. Feuer. Wind profiles in hurricanes determined by GPS dropwindsondes. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 167-168 (1999).

No abstract.

Gamache, J.F. Airborne Doppler observations of intensity change in eastern Pacific Hurricane Guillermo. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 325-328 (1999).

No abstract.

Garzoli, S.L., P.L. Richardson, C.M. Dumcombe Rae, D.M. Fratantoni, G.J. Goni, and A.J. Roubicek. Three Agulhas rings observed during the Benguela Current Experiment. Journal of Geophysical Research, 104(C9):20,971-20,986 (1999).

A field program to study the circulation of the Benguela Current and its extension into the southeastern Atlantic Ocean has completed the survey and instrument deployment phase. We report here new observations of three Agulhas rings north and west of Cape Town, South Africa. Three mesoscale anticyclonic rings initially identified by means of TOPEX/POSEIDON altimetry were surveyed with expendable bathythermographs (XBTs), conductivity-temperature-depth-oxygen (CTDO) profiles, direct current measurements from a lowered acoustic Doppler current profiler (LADCP), a hull-mounted acoustic Doppler current profiler (ADCP), and satellite-tracked surface drifters. Characteristics of the rings are presented and their origins are discussed. Two are typical Agulhas rings surveyed at different times after their generation; the third Agulhas ring has an anomalous watermass structure whose most likely origin is the Subtropical Front.

Garzoli, S.L., D.B. Enfield, G. Reverdin, G. Mitchum, R.H. Weisberg, P. Chang, and J. Carton. COSTA: A Climate Observing System for the Tropical Atlantic. OCEANOBS99: International Conference on the Ocean Observing System for Climate, Saint Raphael, France, October 18-22, 1999. Centre National d'Etudes Spatiales, Vol. 1, 19 pp. (1999).

This paper summarizes the discussions that took place during the COSTA (Climate Observing System for the Tropical Atlantic) workshop held in Miami, Florida during May 1999. The main objective of the workshop was to coordinate the present efforts in the region and to set the scientific basis for an extended and more permanent observing system. The intent of the COSTA workshop, based in the CLIVAR (global) and ACVE (basin) experience, was to formulate the basis for an extended and more permanent (regional) tropical Atlantic observing system, building on the present existing monitoring programs and process studies, and the current scientific underlayment. The first part of this paper establishes the importance and the role of the tropical Atlantic in climate fluctuations and their impact in society. This is followed by a description of the climate variability in the Atlantic sector, its relationship to tropical Atlantic variability, especially sea surface temperature (SST), and to the North Atlantic Oscillation and meridional overturning circulation. The possible mechanisms behind tropical Atlantic SST fluctuations and their relation to climate is also discussed, highlighting, in particular, the role of surface fluxes in the off-equatorial regions, the equatorial ocean-atmosphere interactions, and their relationships to movements of the Inter-Tropical Convergence Zone. The second part of this paper summarizes the scientific discussions and recommendations from the working groups who centered their discussions in the following themes: (1) SST and surface fluxes; (2) sea level and subsurface structure; (3) circulation; and (4) modeling and data assimilation. Finally, the present status of the observing system and a summary of recommendations is presented.

Goldenberg, S.B., and C.W. Landsea. Relationships between decadal-scale fluctuations in vertical shear from NCEP/NCAR reanalysis data and Atlantic basin tropical cyclone activity. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 1089-1091 (1999).

No abstract.

Goni, G.J. Transport estimates of the Kuroshio Current from satellite altimeter data. In Ecosystem Dynamics of the Kuroshio Oyashio Transition Region, M. Terazaki, K. Ohtani, T. Sugimoto, and Y. Watanabe (eds.). Japan Marine Science Foundation, Tokyo, 1-8 (1999).

The Kuroshio, together with the Gulf Stream, its counterpart in the North Atlantic, are the two major western boundary currents in the northern hemisphere. These currents have been viewed as the principal channel of water exchange between the equatorial regions, where heat is added to the oceans to be later removed in the polar regions. The transport of the Kursohio current remains one of the largest uncertainties in the meridional heat flux estimate across the North Pacific subtropical gyre. Estimates of the Kuroshio mean transports vary from 21 Sv to 33 Sv (1 S v =10⁶ m³ s^-1). Some characteristics of the dynamics of this current and its variability will be also briefly addressed in this work. One very important issue in ocean dynamics is to constantly monitor the subsurface thermal structure and transport of a western boundary current. This work presents a methodology that uses a combination of satellite altimetry-derived sea height anomaly and inverted echosounder-derived hydrographic data to estimate the thickness of the ocean upper layer and baroclinic transport. The estimates reveal that during the end of 1996 and beginning of 1997 the Kuroshio Current presents an anomalous behavior.

Goni, G.J., M.M. Huber, and L.K. Shay. TOPEX/POSEIDON-derived Atlantic Ocean hurricane heat content estimates. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, American Meteorological Society 79th Annual Meeting, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 1037-1042 (1999).

No abstract.

Graber, H.C., M.A. Donelan, S. Atakturk, W.M. Drennan, and K.B. Katsaros. Marine flux-profile relations from an air-sea interaction spar buoy. Proceedings, Symposium on the Wind-Driven, Air-Sea Interface, Sydney, Australia, January 10-15, 1999, M. Banner (ed.). The University of New South Wales, 317-324 (1999).

The Air-Sea Interaction Spar (ASIS) is a new autonomous spar buoy designed to permit long-term measurements of processes at the air-sea interface. During a two-month deployment in the Gulf of Mexico in April/May 1997, the buoy recorded waves as high as 3.5 m and wind speeds up to 20 m/s. The ASIS buoy was instrumented to measure high resolution wave directional properties, wind stress, and four level profiles of wind speed, temperature, and humidity. These data are used to examine marine flux-profile relations and to explore the effect of a thick wave boundary layer on the validity of Monin-Obukhov similarity theory.

Gray, J. National Oceanic and Atmospheric Administration research and operation priorities. In Proceedings, South Florida Measurement Center Workshop: Establishment of a Center for Innovative Oceanography in the 21st Century, Dania, FL, February 24-26, 1999. National Science Foundation, 207-213 (1999).

No abstract.

Grima, N., A. Bentamy, K.B. Katsaros, Y. Quilfen, P. Delecluse, and C. Levy. Sensitivity of an oceanic general circulation model forced by satellite wind stress fields. Journal of Geophysical Research, 104(C4):7967-7989 (1999).

Satellite wind and wind stress fields at the sea surface, derived from the scatterometers on European Remote Sensing satellites 1 and 2 (ERS-1 and ERS-2) are used to drive the ocean general circulation model (OGCM) "OPA" in the tropical oceans. The results of the impact of ERS winds are discussed in terms of the resulting thermocline, current structures, and sea level anomalies. Their adequacy is evaluated on the one hand by comparison with simulations forced by the Arpege-Climat model and on the other hand by comparison with measurements of the Tropical Atmosphere-Ocean (TAO) buoy network and of the TOPEX/Poseidon altimeter. Regarding annual mean values, the thermal and current responses of the OGCM forced by ERS winds are in good agreement with the TAO buoy observations, especially in the central and eastern Pacific Ocean. In these regions the South Equatorial Current, the Equatorial Undercurrent, and the thermocline features simulated by the OGCM forced by scatterometer wind fields are described. The impact of the ERS-1 winds is particularly significant to the description of the main oceanic variability. Compared to the TAO buoy observations, the high-frequency (a few weeks) and the low-frequency of the thermocline and zonal current variations are described. The correlation coefficients between the time series of the thermocline simulated by ERS winds and that observed by the TAO buoy network are highly significant; their mean value is 0.73, over the whole basin width, while it is 0.58 between Arpege model simulation and buoy observations. At the equator the time series of the zonal current simulated by the ERS winds, at three locations (110°W, 140°W, and 165°E) and at two depths, are compared to the TAO current meter and acoustic Doppler current profiler (ADCP) measurements. The mean value of the significant correlation coefficients computed with the in-situ measurements in 0.72 for ERS, while it is 0.51 for the Arpege-Climat model. Thus, ERS wind fields through the OGCM generate more realistic current variations than those obtained with Arpege climate winds, and they are particularly efficient in capturing abrupt changes ("wind bursts") which may be important regarding ocean dynamics.

Hansen, D.V., and W.C. Thacker. Estimation of salinity profiles in the upper ocean. Journal of Geophysical Research, 104(C4):7921-7934 (1999).

A new algorithm is presented for estimating salinity profiles in the upper ocean from measurements of temperature profiles and surface salinity. In application to the eastern tropical Pacific the method replicates a large fraction of the variability of salinity in the upper few tens of meters and provides modest to substantial improvement at nearly all levels. Estimated salinity profiles are able to characterize barrier layers, regions formed by a halocline within the thermal mixed layer. The rms error of geopotential-height calculations based on estimated salinity profiles is reduced more than 50 percent by this method relative to methods not using surface salinity. Even without the surface salinity measurement some reduction of error in geopotential heights can be obtained relative to previous methods.

Hellin, J., M. Haig, and F.D. Marks. Rainfall characteristics of Hurricane Mitch. Nature, 399(6734):316 (1999).

No abstract.

Hock, T.F., and J.L. Franklin. The NCAR GPS dropwindsonde. Bulletin of the American Meteorological Society, 80(3):407-420 (1999).

The National Center for Atmospheric Research (NCAR), in a joint effort with the National Oceanic and Atmospheric Administration (NOAA) and the German Aerospace Research Establishment, has developed a dropwindsonde based on the Global Positioning System (GPS) satellite navigation. The NCAR GPS dropwindsonde represents a major advance in both accuracy and resolution for atmospheric measurements over data-sparse oceanic areas of the globe, providing wind accuracies of 0.52 m s^-1 with a vertical resolution of ~5 m. One important advance over previous generations of sondes is the ability to measure surface (10 m) winds. The new dropwindsonde has already been used extensively in one major international research field experiment (Fronts and Atlantic Storm Track Experiment), in operational and research hurricane flights from NOAA's National Weather Service and Hurricane Research Division, during NCAR's SNOWBAND experiment, and in recent CALJET and NORPEX El Ni�o experiments. The sonde has been deployed from a number of different aircraft, including NOAA's WP-3Ds and new Gulfstream IV jet, the Air Force C-130s, NCAR's Electra, and a leased Lear-36. This paper describes the characteristics of the new dropwindsonde and its associated aircraft data system, details the accuracy of its measurements, and presents examples from its initial applications.

Houston, S.H., and M.D. Powell. Hurricanes and tropical storms in Florida Bay. Florida Sea Grant College Program, FLSGP-G-99-016, 2 pp. (1999).

No abstract.

Houston, S.H., W.A. Shaffer, M.D. Powell, and J. Chen. Comparisons of HRD and SLOSH surface wind fields in hurricanes: Implications for storm surge modeling. Weather and Forecasting, 14(5):671-686 (1999).

Surface wind observations analyzed by the Hurricane Research Division (HRD) were compared to those computed by the parametric wind model used in the National Weather Service Sea, Lake, and Overland Surges from Hurricanes (SLOSH) model's storm surge computations for seven cases in five recent hurricanes. In six cases, the differences between the SLOSH and HRD surface peak wind speeds were 6% or less, but in one case (Hurricane Emily of 1993) the SLOSH computed peak wind speeds were 15% less than the HRD. In all seven cases, statistics for the modeled and analyzed wind fields showed that for the region of strongest winds, the mean SLOSH wind speed was 14% greater than that of the HRD and the mean inflow angle for SLOSH was 19° less than that of the HRD. The radii beyond the region of strongest winds in the seven cases had mean wind speed and inflow angle differences that were very small. The SLOSH computed peak storm surges usually compared closely to the observed values of storm surge in the region of the maximum wind speeds, except Hurricane Emily where SLOSH underestimated the peak surge. HRD's observation-based wind fields were input to SLOSH for storm surge hindcasts of Hurricanes Emily and Opal (1995). In Opal, the HRD input produced nearly the same computed storm surges as those computed from the SLOSH parametric wind model, and the calculated surge was insensitive to perturbations in the HRD wind field. For Emily, observation-based winds produced a computed storm surge that was closer to the peak observed surge, confirming that the computed surge in Pamlico Sound was sensitive to atmospheric forcing. Using real-time, observation-based winds in SLOSH would likely improve storm surge computations in landfalling hurricanes affected by synoptic and mesoscale factors that are not accounted for in parametric models (e.g., a strongly sheared environment, convective asymmetries, and stably stratified boundary layers). An accurate diagnosis of storm surge flooding, based on the actual track and wind fields, could be supplied to emergency management agencies, government officials, and utilities to help with damage assessment and recovery efforts.

Houston, S.H., G. Forbes, A. Chiu, W.-C. Lee, and P.P. Dodge. Super Typhoon Paka's (1997) surface winds. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 1032-1033 (1999).

No abstract.

Huang, H., R.E. Fergen, J.J. Tsai, and J.R. Proni. Evaluation of mixing zone models: CORMIX, PLUMES, and OMZA with field data from two Florida ocean outfalls. Proceedings, Second International Symposium on Environmental Hydraulics, Hong Kong, China, December 16-18, 1998. Environmental Hydraulics, pp. 249-254 (1999).

This paper presents an evaluation of three mixing zone models: CORMIX, PLUMES, and OMZA using field data from two Florida ocean outfalls: Hollywood and Miami-Central outfalls. The hollywood outfall has a single port outlet and the Miami-Central outfall has a multiport diffuser. Both outfalls discharge secondary effluent. For the nearfield, all of the three models predict realistic initial dilutions for the tests at the outfall except three cases in CORMIX predictions and two cases in PLUMES predictions (out of 20 cases). For the nearfield and farfield combined, CORMIX significantly overestimates dye concentrations for the tests at the Hollywood outfall but underestimates dye concentrations within the 300 m to 400 m range for the tests at the Miami-Central outfall. PLUMES predictions agree reasonably well with the filed data for the range from 300 m to 800 m but do not agree well within the 300 m range for the tests at both outfalls. OMZA predictions agree well with the field data within the 800 m range for the test at both outfalls.

Huber, M.M., L.K. Shay, and G.J. Goni. The Atlantic Ocean's role on intensity change. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, American Meteorological Society 79th Annual Meeting, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 36-39 (1999).

No abstract.

Humphrey, J.C., S.L. Vargo, J.C. Ogden, and J.C. Hendee. SEAKEYS 1999: Florida Keys monitoring initiative. 1999 Florida Bay and Adjacent Marine Systems Science Conference, Program and Abstracts, Key Largo, FL, November 1-5, 1999. University of Florida Sea Grant Program, 240-241 (1999).

The Sustained Ecological Research Related to the Management of the Florida Keys Seascape (SEAKEYS) program was organized in 1991 by the Florida Institute of Oceanography (FIO) with initial funding from the John D. and Catherine T. MacArthur Foundation, and continuing funding from the South Florida Ecosystem Restoration, Prediction and Monitoring (SFERPM) program, administered by the National Oceanic and Atmospheric Administration (NOAA). The SEAKEYS environmental monitoring program, which is basically an oceanographic extension to the meteorologically-oriented Coastal-Marine Automated Network of NOAA, has accumulated an unparalleled long-term database of meteorological and oceanographic data from the Florida Straits and Florida Bay. During 1998, the SEAKEYS network was upgraded with more precise oceanographic sensors, and selected stations were augmented with fluorometers, transmissometers, and water-level sensing equipment. A seventh monitoring station, a cooperative effort between FIO and the University of South Florida's Department of Marine Science (USF/DMS), was completed in Northwest Florida Bay at 25°05'00"N, 81°05'30"W during summer, 1998. This station also contains a full suite of meteorological and oceanographic instrumentation and also transmits its data hourly via a NOAA GOES satellite. The Northwest Florida Bay station is the northwestern most station in the SEAKEYS network, as well as the southernmost link in the West Florida Coastal Ocean Monitoring and Prediction System of USF/DMS. Turbulent weather was prominent during 1998 in the Florida Keys. Severe conditions reported by the SEAKEYS stations included the Ground Hog Day Storm, Hurricane Georges, and Tropical Storm Mitch. In most cases the SEAKEYS stations contained the only instruments to measure the meteorological and oceanographic measurements accompanying these events in the Florida Keys. The Long Key station measured the highest winds (119 mph) in South Florida during the Ground Hog Day Storm of February 2, 1998. On September 25, 1998 the eye of Hurricane Georges passed over Key West at 1150 EDT as wind speeds dropped from 85.2 mph to 9.6 mph. The eye moved across the Dry Tortugas station at 1610 EDT with barometric pressures dropping to 974.4 mb. Winds gusted to hurricane force only after the eye passed at 2100 EDT. Georges' most severe winds in the Florida Keys gusted to 113 mph at Sombrero Reef, with a sustained wind speed of 94 mph. Long Key, Molasses Reef, and Fowey Rocks received gusts of tropical storm force. The tide station at Sombrero Reef reported a storm water level of 2.87 feet above mean lower low water. This contrasted with below normal levels reported at a station on Florida Bay. Hurricane Mitch passed northwest of the Florida Keys on the evening of November 4, 1998, bringing peak winds of 62.4 mph at Molasses Reef and sustained gale force winds until the following afternoon. Numerous localized tornadoes spawned by this storm caused extensive damage in the Upper Keys. Daily near real-time SEAKEYS data are available to researchers via NOAA's Coral Health and Monitoring Program (CHAMP) Web site at http://www.coral.noaa.gov, while historical data are available at http://www.neptune.noaa.gov. The Coral Reef Early Warning System (CREWS), which utilizes the near real-time data from six SEAKEYS stations, is an online expert system which monitors environmental conditions on the reef that are theoretically conducive to coral bleaching. If these conditions occur, alerts are sent via email to researchers and posted to the Web at http://www.coral.noaa.gov/sferpm/seakeys/es.

Jodoin, C. Detection of direct-sequence spread-spectrum signals in a multipath fading environment. M.S. thesis, Florida Atlantic University, Boca Raton, FL, 120 pp. (1999).

In this thesis, we study the effect of Rice fading on the performance of Global Positioning System (GPS) receivers. The field-theoretic foundation of pseudo-random-noise (PRN) codes, their implementation, and their use in generating unique navigation messages in the GPS receiver is reviewed. The processing of the spread-spectrum signals within the digital delay locked loop (DDLL) in the receiver is also considered. In particular, we derive numerical expressions that can be easily evaluated for the probability error and the mean-time to lose-lock, for a DDL operating in an additive white Gaussian noise (AWGN) channel in the presence of Rice fading. The results obtained generalize results in the literature for the Rayleigh fading environment.

Johns, E., W.D. Wilson, and T.N. Lee. Surface salinity variability of Florida Bay and southwest Florida coastal waters. 1999 Florida Bay and Adjacent Marine Systems Science Conference, Programs and Abstracts, Key Largo, FL, November 1-5, 1999. University of Florida Sea Grant Program, 169-171 (1999).

No abstract.

Johns, E., W.D. Wilson, and R.L. Molinari. Direct observations of velocity and transport in the passages between the Intra-Americas Sea and the Atlantic Ocean, 1984-1996. Journal of Geophysical Research, 104(C11):25,805-25,820 (1999).

Shipboard acoustic Doppler current profiler observations of the velocity in the upper 200 m of the water column collected during 1984-1996 using the National Oceanic and Atmospheric Administration R/V Malcolm Baldrige are used to examine the velocity structure and transport in the passages between the Atlantic Ocean and the Intra-Americas Sea (IAS). Data were colected during 23 cruises along the following sections: across the Straits of Florida, in the Northwest Providence Channel (NWPC), across the northern passages into the Caribbean Sea (Windward, Mona, and Anegada), across the eastern Caribbean along 63°30'W, thereby forming a closed quadrangle, and in the Grenada Passage. The Florida Current, the eastern Caribbean, and the Grenada Passage share a similar mean velocity structure characterized by high-velocity, surface intensified flows with strong vertical and horizontal shears. The northern Caribbean passages (NWPC, Windward, Mona, and Anegada) share a different common mean velocity structure, with subsurface velocity maxima directed into the IAS, and surface-intensified counterflows along one side of each paassage. On average, there is a transport balance in the upper 200 m between waters entering and exiting the IAS, with the 16.5 ± 2.4 Sv (1 Sv = 10⁶ m³ s^-1) transport of the Florida Current at 27°N comprised of 0.4 ± 0.8 Sv from the NWPC, 2.2 ± 1.5 Sv from the Windward Passage, 2.8 ± 2.1 and 2.4 ± 2.8 Sv from the Mona and Anegada passages, respectively, and 9.5 ± 4.7 Sv across the eastern Caribbean, for a total of 17.3 Sv. The four passages north of 17°N (from NWPC to Anegada Passage) have a combined transport of 7.8 Sv, nearly half of the transport of the Florida Current in the upper 200 m. Of the 9.5 Sv flowing through the eastern Caribbean between 11°N and 17°N, 4.9 ± 2.6 Sv, or more than half, come from the Grenada Passage. This is significant to the subject of cross-equatorial exchange of mass, heat, and salt, as the Grenada Passage is where the highest transport of waters originating in the southern hemisphere is thought to enter the Caribbean.

Jones, R.W., and M. DeMaria. Further studies of the optimization of a hurricane track prediction model using the adjoint equations. Monthly Weather Review, 127(7):1586-1598 (1999).

The method of model fitting, or adjoint method, is applied to a barotropic hurricane track forecast model described by DeMaria and Jones using a large sample of forecast cases. The sample includes all Atlantic tropical cyclones that reached hurricane intensity during the 1989-1993 hurricane seasons (141 72-h forecasts of 17 storms). The cases considered by DeMaria and Jones are a subset of the present sample. Model-fitting calculations using strong, weak, strong followed by weak, or weak followed by strong model constraints are discussed for data assimilation periods varying from 6 to 72 h. Generally, the best track forecasts occur for shorter assimilation periods and for weak constraints, although only the 12-h assimilation with the weak constraint has less track error than the control forecast without assimilation, and only for the 12-h forecast. The principle reason for this lack of improvement is that the fit of the model to the observed track is good at the middle of the assimilation period, but not very good at the end where the forecast begins. When a future track position at 6 h is included in the assimilation, in order to improve the track fit at the synoptic data time, the resulting track errors average about 10% smaller than the control forecast. The control forecast may also be improved in the same way. In that case, the best assimilation forecasts have 2.5% smaller track errors than the modified control forecasts.

Jones, R.W., and H.E. Willoughby. Results of generalizing a semispectral shallow-water barotropic hurricane tracking model into a two-layer baroclinic model. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 747-750 (1999).

No abstract.

Kaplan, J., and M. DeMaria. Climatological and synoptic characteristics of rapidly intensifying tropical cyclones in the North Atlantic basin. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 592-595 (1999).

No abstract.

Landsea, C.W., R.A. Pielke, A.M. Mestas-Nunez, and J.A. Knaff. Atlantic basin hurricanes: Indices of climatic changes. Climatic Change, 42(1):89-129 (1999).

Accurate records of basin-wide Atlantic and U.S. landfalling hurricanes extend back to the mid 1940s and the turn of the century, respectively, as a result of aircraft reconnaissance and instrumented weather stations along the U.S. coasts. Such long-term records are not exceeded elsewhere in the tropics. The Atlantic hurricanes, U.S. landfalling hurricanes, and U.S. normalized damage time series are examined for interannual trends and multidecadal variability. It is found that only weak linear trends can be ascribed to the hurricane activity and that multidecadal variability is more characteristic of the region. Various environmental factors including Caribbean sea level pressures and 200 mb zonal winds, the stratospheric Quasi-Biennial Oscillation, the El Niño-Southern Oscillation, African West Sahel rainfall, and Atlantic sea surface temperatures, are analyzed for interannual links to the Atlantic hurricane activity. All show significant, concurrent relationships to the frequency, intensity, and duration of Atlantic hurricanes. Additionally, variations in the El Niño-Southern Oscillation are significantly linked to changes in U.S. tropical cyclone-caused damages. Finally, much of the multidecadal hurricane activity can be linked to the Atlantic Multidecadal Mode, an empirical orthogonal function pattern derived from a global sea surface temperature record. Such linkages may allow for prediction of Atlantic hurricane activity on a multidecadal basis. These results are placed into the context of climate change and natural hazards policy.

Landsea, C.W., C.A. Anderson, G. Clark, J. Fernandez-Partagas, P. Hungerford, C. Neumann, and M. Zimmer. The Atlantic hurricane database re-analysis project. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 394-397 (1999).

No abstract.

Lapitan, R.L., R.H. Wanninkhof, and A.R. Mosier. Methods for stable gas flux determination in aquatic and terrestrial systems. In Approaches to Scaling of Trace Gas Fluxes in Ecosystems, A.F. Bouwman (ed.), Elsevier, Amsterdam, 27-66 (1999).

A general description of the current approaches for measuring trace gas fluxes in aquatic and terrestrial systems is presented in this paper. Our aim is to provide an overview of the current methodologies employed in trace gas flux measurements and the most recent advancements made; with emphasis on the uncertainties observed and potential areas for future developments required to further minimize these uncertainties brought about by spatial and temporal variabilities of fluxes in the field. The increase in sensitivity and improved response time of analytical devices for measuring trace gases within the last five years, such as advancements in laser spectroscopy, have significantly improved the effectiveness of the current methods of measuring these gases in aquatic and terrestrial systems. Systematic errors in trace gas flux estimates have also been reduced with the refinements in estimates of the gas transfer velocity,k, through the use of tracers in the two systems. Footprint corrections of micrometeorological flux measurements in terrestrial systems have provided a better means of identifying the spatial sources of trace gases, and thus, have increased the scope of inference from trace gas flux measurements. Despite these improvements, however, flux measurement errors still remain high. Experimental and sampling designs that can efficiently and effectively deal with the spatial and temporal variabilities in trace gas flux measurements to the minimum are of utmost priority. The same can be said of the modeling procedures; that is, there is a need for an effective method that can reduce instead of propagate potential errors in scaling from field plot to regional or global scales.

Lee, K., R.H. Wanninkhof, R.A. Feely, F.J. Millero, and T.-H. Peng. Global distribution of total inorganic carbon in surface water. Proceedings, Second International Symposium on CO₂ in the Oceans, Tsukuba, Japan, January 18-22, 1999. Center for Global Environmental Research (CGER-I037-99), 493-496 (1999).

No abstract.

Lee, K., R.H. Wanninkhof, T. Takahashi, S.C. Doney, and R.A. Feely. Interannual variations in oceanic uptake of anthropogenic carbon dioxide for the period of 1982-1995. Proceedings, Second International Symposium on CO₂ in the Oceans, Tsukuba, Japan, January 18-22, 1999. Center for Global Environmental Research (CGER-I037-99), 31-34 (1999).

No abstract.

Lee, T.N., E. Williams, E. Johns, and W.D. Wilson. First year results from enhanced observations of circulation and exchange processes in western Florida Bay and connecting coastal waters, including effects of El Ni�o and Hurricane Georges. 1999 Florida Bay and Adjacent Marine System Science Conference, Programs and Abstracts, Key Largo, FL, November 1-5, 1999. University of Florida Sea Grant Program, 145-147 (1999).

No abstract.

Majumdar, S.J., S.D. Aberson, C.H. Bishop, and Z. Toth. Real time hurricane track targeting using a VICBAR ensemble. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 755-756 (1999).

No abstract.

Marks, F.D., P.P. Dodge, and C. Sandin. WSR-88D observations of hurricane atmospheric boundary layer structure at landfall. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 1051-1054 (1999).

No abstract.

Marks, F.D., P.P. Dodge, and C. Sandin. WSR-88D observations of hurricane atmospheric boundary layer structure at landfall. Preprints, 29th International Conference on Radar Meteorology, Montreal, Quebec, Canada, July 12-16, 1999. American Meteorological Society, Boston, 374-377 (1999).

No abstract.

McGillis, W., J. Edson, and R.H. Wanninkhof. Direct air-sea flux measurements of carbon dioxide over the North Atlantic Ocean and the comparison to indirect methods. Proceedings, Second International Symposium on CO₂ in the Oceans, Tsukuba, Japan, January 18-22,1999. Center for Global Environmental Research (CGER-I037-99), 367-377 (1999).

To date, large uncertainties in the extent of the CO₂ flux between the atmosphere and ocean have prevented us from accurately quantifying how the increasing atmospheric CO₂ burden partitions between the ocean and the terrestrial biosphere. This limits our ability to accurately predict future atmospheric CO₂ levels. We have recently designed a direct CO₂ flux measurement system that considerably improves our estimates of air-sea gas exchange. The system measures the direct air-sea flux of CO₂ in the atmospheric boundary layer using eddy correlation (direct covariance). It was successfully deployed during the large scale experiment to study air-sea gas fixes, GASES98, which was conducted in the CO₂ sink region of the North Atlantic during May/June of 1998. The seasonal algal bloom caused air-sea pCO₂ differences of between -80 to ~100 µatm. This large concentration gradient generated large signals for accurate measurement of the CO₂ flux using a close path CO₂ sensor. In addition to the CO₂ gas flux, the comprehensive atmospheric flux measurement suite included momentum, heat, and moisture fluxes. Atmospheric flux and air-sea gas concentration measurements were performed for over 500 hours, providing more than 1000 observations. Wind speeds between 1 and 16 m/s were experienced over the range of these observations. Preliminary flux estimates from our system compare extremely well with previous estimates of the gas transfer velocity for wind speeds below 7 m/s. At higher wind speeds, the transfer velocities obtained from our system are as much as 20-50% higher than those estimated by empirical relationships. Based on accurate air-sea CO₂ coefficients obtained by our investigation and atmospheric and surface ocean pCO₂ data obtained to date, estimates of the global ocean CO₂ sink are now feasible. Our findings will also provide better predictions of the seasonal and interannual variability of sea-air CO₂ flux observed in various global regions.

McPhaden, M.J., T. Delcroix, K. Hanawa, Y. Kuroda, G. Meyers, J. Picaut, and M.S. Swenson. The ENSO observing system. OCEANOBS99: International Conference on the Ocean Observing System for Climate, Saint Raphael, France, October 18-22, 1999. Centre National d'Etudes Spatiales, Vol. 1, 14 pp. (1999).

This paper reviews the status of the ENSO (El Ni�o-Southern Oscillation) observing system, with emphasis on the Pacific Ocean during the recent 1997-1998 El Ni�o and subsequent La Ni�a. Contributions of this system to detection, monitoring, forecasting, and understanding of ENSO-related climate swings will be described. Recommended enhancements and extensions to the observing system will also be presented.

McTaggart, K.E., G.C. Johnson, C.I. Fleurant, and M.O. Baringer. CTD/O₂ measurements collected on a Climate and Global Change cruise along 24°N in the Atlantic Ocean (WOCE section A6) during January-February 1998. NOAA Data Report, ERL PMEL-68 (PB99-155194), 368 pp. (1999).

Summaries of CTD/O₂ measurements and hydrographic data acquired on a Climate and Global Change cruise during the winter of 1998 aboard the NOAA ship Ronald H. Brown are presented. The majority of these data were collected along 24.5°N from 23.5°W to 69°W. Completing the transatlantic section are data collected along a northeast-southwest dogleg off the coast of Africa, and along a second, short, zonal section along 26.5°N off the coast of Abaco Island from 69°W to 77°W, jogging north along 27°N in the Straits of Florida to 80°W. Data acquisition and processing systems are described and calibration procedures are documented. Station location, meteorological conditions, CTD/O₂ summary data listings, profiles, and potential temperature-salinity diagrams are included for each cast. Section plots of oceanographic variables and hydrographic data listings are also given.

Mestas-Nunez, A.M., and D.B. Enfield. Rotated global modes of non-ENSO sea surface temperature variability. Journal of Climate, 12(9):2734-2746 (1999).

A varimax rotation was applied to the EOF modes of global SST derived by Enfield and Mestas-Nuñez (1999). The SST anomaly record is more than a century long, with a global complex EOF representation of ENSO and a linear trend removed at every grid point. The rotated EOF modes capture localized centers of variability that contribute to the larger scale spatial patterns of the unrotated modes. The first rotated EOF represents a multidecadal signal with larger response in the North Atlantic. The second rotated EOF represents an interdecadal uctuation with larger response in the eastern North Pacific and out of phase fluctuations of smaller amplitude in the central North Pacific. The third rotated EOF captures interdecadal fluctuations in the eastern tropical Pacific with a dominant peak that coincides with the 1982-83 ENSO. The fourth rotated EOF has an interdecadal to multidecadal nature with larger response in the central equatorial Pacific and quasi-symmetric out of phase response in the western North and South Pacific. The fifth mode represents multidecadal fluctuations with large response at about 40°N in the North Pacific. The sixth mode has interannual to interdecadal time scales with largest response confined to the South Atlantic. Our rotated modes are dominated by intra- rather than interocean uctuations supporting the hypothesis that the non-ENSO variability is more regional than global in nature. Analyses of sea level pressure and surface wind stress show that in general the non-ENSO rotated EOFs are consistent with an ocean response to local atmospheric forcing. An exception is the eastern tropical Pacific mode which is more consistent with an atmospheric response to changes in the ocean SST.

Mestas-Nunez, A.M., and D.B. Enfield. Rotated global modes of non-ENSO sea surface temperature. Proceedings, 23rd Annual Climate Diagnostics and Prediction Workshop, Miami, Florida, October 26-30, 1998. National Weather Service, 162-165 (1999).

No abstract.

Molinari, R.L. Lessons learned from operating global ocean observing networks. Bulletin of the American Meteorological Society, 80(7):1413-1420 (1999).

The Global Ocean Observing System Center (GOOSC) at the National Oceanic and Atmospheric Administration's (NOAA) Atlantic Oceanographic and Meteorological Laboratory operates two global observing networks, a drifting buoy array, and a Voluntary Observing Ship network. The arrays provide in real time surface atmospheric and subsurface oceanographic data needed by NOAA weather and climate forecasters. The data are used in delayed mode to verify model simulations of the ocean and atmosphere, to provide in situ calibration/validation data for remote sensing observations, and to increase understanding of the dynamics of the ocean and atmosphere. The operational and research lessons learned in the operation of the GOOSC are reviewed. Operationally, it was learned that, because of costs, international participation is required to maintain global networks; data management methodology is a critical component of operations; and integrated observing systems using multiple platforms provide more accurate products. Scientifically, it was learned, for example, that accurate characterizations of the salinity field must be available in model simulations. As more data become available it is found that scales of important phenomena such as equatorial upwelling are smaller, and high-frequency signals can impact on the mean structure of the upper ocean. These findings must be considered when designing effective sampling strategies.

Molinari, R.L., S.L. Garzoli, and R.W. Schmitt. Equatorial currents at 1000 m in the Atlantic Ocean. Geophysical Research Letters, 26(3):361-364 (1999).

Twenty-seven Profiling ALACE (PALACE) floats were deployed in the equatorial Atlantic during July-August 1997. The floats were ballasted to drift at 1000 m for 10 to 14 days, return to the surface while obtaining a temperature profile, transmit data via satellite, and then after one day return to 1000 m. One-year float paths are now available. Floats deployed on the equator were launched into a deep westward jet. The jet extends some 1-2° north of the equator, with eastward motion observed in floats to the north of 2°N. The equatorial current reverses in the central basin to the east in mid-October and then back to the west in mid-February. Flow to the north also reverses. The short space and time scales contrast with earlier work based on fewer floats that inferred space scales of some 5 -10 in latitude and time scales greater than one year. The new results are consistent with models that indicate that equatorial Rossby waves are the cause of the reversing currents.

Morisseau-Leroy, N., M.K. Solomon, G.P. Momplaisir, T. Kurian, and E. Griffin. Oracle 8I SQLJ Programming. Osborne McGraw-Hill (ISBN 0072121602), 557 pp. (1999).

No abstract.

Murillo, S.T., and J.J. O'Brien. The influence of ENSO on eastern Pacific tropical cyclones. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 437-438 (1999).

No abstract.

Murillo, S.T., P.P. Dodge, W.-C. Lee, and F.D. Marks. Using the GBVTD technique in nowcasting hurricane windfields using the WSR-88D. Preprints, 29th International Conference on Radar Meteorology, Montreal, Quebec, Canada, July 12-16, 1999. American Meteorological Society, Boston, 276-277 (1999).

No abstract.

Murillo, S.T., W.-C. Lee, K. Hondl, P.P. Dodge, C. McAdie, and F.D. Marks. Implementation of the GBVTD technique in nowcasting hurricane wind fields using the WSR-88D. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 311-312 (1999).

No abstract.

Nelsen, T.A., and J.R. Proni. Distribution and movement of discharged dredged material at the San Juan Ocean Disposal site. Final Report to the U.S. Army Corps of Engineers, MIPR No. W32CS580843181, 57 pp. (1999).

No abstract.

Nelsen, T.A., and J.R. Proni. Signatures contained in suspended particulate matter with application to coastal-ocean environmental studies. In Coastal Engineering and Marine Developments, C. Brebbia and P Anagnostopoulos (eds.). WIT Press, Southampton, 328-346 (1999).

Suspended particulate matter (SPM) samples from the New York Bight Apex collected during a sewage-dump experiment were analyzed for chemical as well as physical parameters such as particle-size distributions. The latter provided a signature of the SPMs' sewage component that allowed differentiation from other components. These results were applied to a series of eight Water Column Characterization (WCC) cruises in this area. Co-analysis of WCC and sewage dump particle-size distributions by factor analysis and Distribution Component Analysis revealed patterns that allowed differentiation of sewage-derived components for all WCC samples. From this, a long-termed budget of SPM components, including sewage-derived materials, was constructed. Given this, we conclude that useful tools are available for developing signatures of anthropogenic components of SPM plumes which are independent of study sites or subject materials. These signatures can be applied to understand the sources, pathways, and sinks of such materials in the coastal ocean, as well as constructing long-termed budgets thereof. Ultimately such estimates can be critical to waste management strategies and decisions in an ever more anthropogenically-impacted coastal ocean.

Nelsen, T.A., G. Garte, C.M. Featherstone, P.L. Blackwelder, T. Hood, C. Alvarez-Zarikian, P. Swart, H.R. Wanless, L. Tedesco, C. Souch, J. Pachut, and J. Arthur. Understanding long-term rainfall, freshwater flow, and salinity patterns with concomitant responses of benthic microfauna, stable isotopes, and pollen in Oyster and Florida Bays. 1999 Florida Bay and Adjacent Marine Systems Science Conference, Programs and Abstracts, Key Largo, FL, November 1-5, 1999. University of Florida Sea Grant Program, 189-190 (1999).

Salinity records exhibited variability from the decadal scale to the monthly scale that can be accounted for by changing patterns in regional rainfall. Changes in salinity, both near the outflow of the Shart River Slough at Oyster Bay, and in central Florida Bay near Jimmy Key, show a direct response to regional rainfall on these time scales. Moreover, regional rainfall, represented by the 80+ year record at Homestead, Florida, proved representative of the study area and indicated high correlation with flow into Shark River Slough prior to major watershed construction instigated in the early 1960s. During subsequent periods of water management strategies, enacted from the mid-1960s to present, results indicate essentially no correlation between regional ranfall and flow during the Monthly Allocation Plan. In contrast, correlations most closely paralleled pre-construction, apparently more natural condtions, during the Rainfall Plan. Investigated characteristics for the benthic microfaunal community (foraminifers and ostracods) such as stable isotopes, abundance, and community diversity, exhibited changes and trends that apparently more closely paralleled natural rather than anthropogenic influences over the whole period of record. At both Jimmy Key and Oyster Bay, foraminifer and ostracod data indicate direct correlation to rainfall patterns for temporal scales ranging from decadal down to the limit-of-resolution of our geochronology. An exception to this natural influence was observed from the late-1940s to mid-1950s during which time a dual transition occurred in the sediments adjacent to the Shark River Slough in Oyster Bay. Organic carbon content permanently declined from above- to below-average with concurrent onset of major increases in foraminifer and ostracod abundances. These events temporally conicided with the construction of the Everglades Agricultural Area, which impounded 700,000 acres of organic-rich swampland. These effects were not observed for sediments representing the same time period at Jimmy Key. Stable isotope (delta ¹⁸O, delta ¹³O) trends alone for ostracods and foraminifers at Oyster Bay and Jimmy Key showed mixed signals, with most data suggesting upcore trends to less fresh, more marine conditions. However, when long-term trends for relative abundance of salinity-sensitive species were examined, for the same time periods and locations, they confirmed a statistically valid upcore trend toward less fresh, more marine conditions at both Oyster and Florida Bay study sites. This trend was coincident with a weak decline in regional rainfall over the same time span. Changes in the stable isotopic values of these microfauna indicated, to the limits of our geochronology, direct responses to regional rainfall. Such responses more closely paralleled rainfall than freshwater runoff, even adjacent to the outflow of the Shark River Slough. At Oyster Bay, istracod stable isotope (delta¹⁸O) trends correlated better with variabions in regional rainfall than with freshwater outflow from the adjacent Shark River Slough. Crashes in microfaunal abundances at Oyster Bay and more gradual declines at Jimmy Key were salinity related. This abundance drop was concurrent with an equally dramatic drop in community diversity. The latter was characterized by survivor-mode dominance by two microfaunal species and occurred over a period of drought at both sites and the related reduced flow from Shart River Slough. A non-traditional use of pollen allowed evaluation of the degree of paleo-flushing from Shark River Slough that not only correlated well with existing flow and rainfall records but suggests validity as a flushing proxy for pre-record eras. Analysis of regional pollen indicated taxa associations that allowed discrimination of pollen zonations from coastal mangrove to upland slough environments. This, in turn, allowed reconstruction in the sediment record of historical periods of major to minor flushing from Shark River Slough.

Ooyama, K.V. Boundary-layer parameterization in a cloud-resolving model using the radical thermodynamic formulation. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 150-152 (1999).

No abstract.

Ortner, P.B., L.B. Crowder, and D.E. Hoss. The South Atlantic Bight Recruitment Experiment: Introduction and overview. Fisheries Oceanography, 8(2):1-6 (1999).

The South Atlantic Bight Recruitment Experiment (SABRE) brought together an interdisciplinary team of scientists to conduct research to enhance our understanding of the relationship between variation in environmental factors and the variable recruitment of "estuarine dependent" fishes within the South Atlantic Bight. The project sought to develop a new fusion of government and academic scientists, each possessing unique skills, to address the difficult problem of recruitment variability in fishes. This fusion required the development of appropriate and, at that time, novel management and administrative strategies. SABRE initially focused on recruitment dynamics of Atlantic menhaden, Brevoortia tyrannus, in the South Atlantic Bight, but expanded over time to include several estuarine-dependent species and much of the Middle Atlantic Bight as well. The project was conducted from 1991 to 1997 and resulted in a substantial improvement in our understanding of the life history and ecology of Atlantic menhaden and the potential constraints upon its recruitment. SABRE also contributed to our understanding of the physical oceanography of the western North Atlantic shelf and adjacent coastal inlets and the implications of physical dynamics upon the potential pathways for larval transport.

Ortner, P.B., M.J. Dagg, G.S. Kleppel, and C.R. Tomas. Grazing by zooplankton in Florida Bay waters. Florida Sea Grant College Program, FLSGP-G-99-012, 2 pp. (1999).

No abstract.

Palmer, D.R. Parabolic approximations for global acoustic propagation modeling. NOAA Technical Memorandum, ERL AOML-94 (PB99-171571), 54 pp. (1999).

Motivated by the difficulty in using the splitting matrix method to obtain parabolic approximations to complicated wave equations, we have developed an alternative method. It is three-dimensional, does not a priori assume a preferred direction or path of propagation in the horizontal, determines spreading factors, and results in equations that are energy conserving. It is an extension of previous work by several authors relating parabolic equations to the horizontal ray acoustics approximation. Unlike previous work, it applies the horizontal ray acoustics approximation to the propagator rather than to the Green's function or the homogenous field. The propagator is related to the Green's function by an integral over the famous "fifth parameter" of Fock and Feynman. Methods for evaluating this integral are equivalent to narrow-angle approximations and their wide-angle improvements. When this new method is applied to simple problems, it gives the standard results. In this paper, it is described by applying it to a problem of current interest: the development of a parabolic approximation for modeling global underwater and atmospheric acoustic propagation. The oceanic or atmospheric waveguide is on an Earth (or other heavenly body) that is modeled as an arbitrary convex solid of revolution. The method results in a parabolic equation that is energy conserving and has a spreading factor that describes field intensification for antipodal propagation. Significantly, it does not have the singularities in its range-sliced version possessed by many parabolic equations developed for global propagation. The work is generalized to allow for refracted geodetics and the possibility that the depth dependence of the pressure field can be described by adiabatic normal modes.

Peng, T.-H., and F. Chai. Modeling the carbon cycle in the equatorial Pacific Ocean. Proceedings, Second International Symposium on CO₂ in the Ocean, Tsukuba, Japan, January 18-22, 1999. Center for Global Environmental Research (CGER-I037-99), 183-189 (1999).

As part of the U.S. JGOFS SMP program, we have developed an ocean ecosystem model of the equatorial Pacific Ocean with new and export productivity regulated by Si and Fe to synthesize and to analyze data collected during the process-study-oriented survey cruises in 1992. The circulation model is based on the Modular Ocean Model of the NOAA/GFDL ocean general circulation model. The ecosystem model consists of nine components describing two size phytoplankton, two size zooplankton, two detritus pool, and three dissolved nutrients: silicate, nitrate, and ammonium. The carbonate chemistry is parameterized in the model to evaluate the variations of pCO₂, and hence the CO₂ flux across the air-sea interface. At this initial stage, a test case by using a 1D model is performed to simulate low-silicate, high-nitrate, and low-chlorophyll conditions in the equatorial Pacific, and to investigate how the carbon system behaves in this ecosystem structure. The model includes the vertical upwelling and diffusion processes. The upwelling rate and vertical diffusivity were initially averaged for the region 5°S to 5°N, 180°W to 90°W, the "cold tongue" of the equatorial Pacific from the parameter values of 3D model simulations. Temperature is used to calibrate model upwelling and vertical diffusion rates. Comparison of model results with the observations made during the NOAA/OACES EqPac 1992 expeditions indicates that the vertical profiles of DIC, NO₃ and Si(OH)₄ are consistent with the measurements made in the fall season when the ocean was in a normal non-El Niño condition. A tight fit of profiles between model and observation is not possible because of spatial variations of the observed values. A 3D simulation is required, which is in progress. The 1D model CO₂ evasion rate is estimated to be 2.9 mol/m²/yr, which is within the range of estimates from measurements made during non-El Niño conditions.

Peng, T.-H., J.-J. Hung, R.H. Wanninkhof, and F.J. Millero. Carbon budget in the East China Sea in spring. Tellus B, 51(2):531-540 (1999).

Results of total dissolved inorganic carbon (DIC) and total alkalinity (TA) measurements made in the East China Sea (ECS) during a geochemical expedition of KEEP (Kuroshio Edge Exchange Processes) program in May of 1996 show that ECS is a CO₂ sink during the spring season. The mean difference of fCO₂ (fugacity of CO₂) between the atmosphere and surface water is calculated to be 28 µatm, and the resulting net CO₂ invasion flux is 2.1 mol/m²/yr, which gives about 0.03 GtC/yr of CO₂ uptake in this continental shelf in spring. This study supports the notion that shelf regions can be a significant CO₂ sink. The riverine alkalinity, which discharges into ECS, is estimated to be 1,743 µmol/kg on the basis of a linear relationship between TA and salinity. The observed salinity-normalized alkalinity in ECS is higher than that in the open sea, and this excess alkalinity is estimated to be 42 µmol/kg. With the known rate of the Changjiang discharge, this excess TA gives a mean residence time of 1.2 years for the continental shelf water in the ECS. The DIC in the ECS is also found to be higher than that in the open sea. This excess DIC is estimated to be about 76 ± 70 µmol/kg, which is equal to a net carbon input to ECS of 3.9 ± 3.6 mol/m²/yr. Based on the riverine alkalinity input, the equivalent riverine carbon flux from Changjiang discharge is estimated to be about 1.8 mol/m²/yr. With net CO₂ invasion flux of 2.1 ± 2.8 mol/m²/yr, the remaining 0 ± 4.6 mol/m²/yr could come from remineralization of organic matter derived from biological pump in the shelf or terrestrial sources. Although this preliminary carbon budget implies that gas exchange and riverine input are the main sources of excess carbon in ECS, the contribution of biological carbon flux can not be ruled out because of the large uncertainty associated with these estimates.

Pielke, R.A., and C.W. Landsea. La Ni�a, El Ni�o, and Atlantic hurricane damages in the United States. Bulletin of the American Meteorological Society, 80(10):2027-2034 (1999).

Hurricanes result in considerable damage in the United States. Previous work has shown that Atlantic hurricane landfalls in the United States have a strong relationship with the El Ni�o-Southern Oscillation phenomena. This paper compares the historical record of La Ni�a and El Ni�o events defined by eastern Pacific sea surface temperature with a data set of hurricane losses normalized to 1997 values. A significant relationship is found between the ENSO cycle and U.S. hurricane losses, with La Ni�a years exhibiting much more damage. Used appropriately, this relationship is of potential value to decision makers who are able to manage risk based on probabilistic information.

Pielke, R.A., C.W. Landsea, R.T. Musulin, and M. Downton. Evaluation of catastrophe models using a normalized historical record: Why it is needed and how to do it. Journal of Risk and Insurance, 18(2):177-194 (1999).

This article explains the role of catastrophe simulation models in managing exposures to hurricane losses. The credibility and accuracy of these models have been called into question by consumer groups and regulators. This paper suggests a practical method for establishing a baseline to test the skill of these models in estimating catastrophe losses. In establishing a baseline for model evaluation, performance can be measured quantitatively. Given the vast exposure of society to the impacts of catastrophic events, it is imperative that the financial markets of the world develop effective strategies to manage risk. It follows that such strategies will be more effective to the degree that they are based on reliable and publicly understood estimates of future risk. Finally, the transparent nature of the proposed methodology, in contrast to the complex and often proprietary structure of the computer models, highlights the societal factors underlying the sharp increase in catastrophic loss exposure.

Powell, M.D. Hurricanes at landfall. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 107-108 (1999).

No abstract.

Powell, M.D., and S.H. Houston. Comments on "A multiscale numerical study of Hurricane Andrew (1992). Part I: Explicit simulation and verification." Monthly Weather Review, 127(7):1706-1710 (1999).

No abstract.

Powell, M.D., T.A. Reinhold, and R.D. Marshall. GPS sonde insights on boundary layer wind structure in hurricanes. Proceedings, 10th Conference on Wind Engineering, Copenhagen, Denmark, June 21-24, 1999. ICWE, 307-314 (1999).

No abstract.

Powell, M.D., P.G. Black, S.H. Houston, and T.A. Reinhold. GPS sonde insights on boundary layer structure in hurricanes. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 881-884 (1999).

No abstract.

Proni, J.R., and T.A. Nelsen. Integrated measurements of sewage effluent and dredged material discharges. In Coastal Engineering and Marine Developments, C. Brebbia and P Anagnostopoulos (eds.). WIT Press, Southampton, 368-379 (1999).

A series of measurements to characterize sewage effluent discharge plumes and dredged material discharge plumes were carried out in coastal ocean waters off the coast of Puerto Rico in April 1998. A multiple sensor suite including an acoustic backscatter profiler, a towed optical backscatter containing CTD device, a vertical cast CTD having an optical transmissometer and oxygen sensors, and an acoustic Doppler current profiler (ADCP) was utilized to determine the subsurface plume spatial distribution and dilution. The sewage effluent plumes resulted from discharges at several diffusers located approximately one or more miles from the coastline. Using the multiple sensor systems listed above, it was possible to relate measurements made at water locations distant from the diffuser to plumes emanating from various parts of the diffuser under study. That is, a "connectivity" was established so that quantities inherent in the effluent discharge could be used for dilution calculations. Typical "initial" dilutions observed were on the order of 60:1. Using inherent tracers, such as plume salinity, effluent plume distributions were determined out to several hundred meters from the diffuser. "Macro" scale comparisons of multiple sensor outputs were carried out with good general agreement on plume distributions. Comparisons between in-situ "contact" sensors, e.g., temperature and salinity probes, and in-situ remote sensor probes, e.g., optical and acoustic backscatter, optical transmissivity (transmissometry), were made with good agreement resulting.

Proni, J.R., and T.A. Nelsen. Puerto Rico outfall/dredged material disposal studies: April 13-26, 1998. Contract EPA/IAG DW13937869-01-04 (Final report). U.S. Environmental Protection Agency, 74 pp. (1999).

No abstract.

Quilfen, Y., A. Bentamy, K.B. Katsaros, and G. Lorand. Estimation of ocean-atmosphere turbulent fluxes from satellite measurements. Proceedings, 1999 International Geoscience and Remote Sensing Symposium (IGARSS '99), Hamburg, Germany, June 28-July 2, 1999. Institute of Electrical and Electronic Engineers, 2 pp. (1999).

No abstract.

Reasor, P.D., M.T. Montgomery, and F.D. Marks. The asymmetric structure of Hurricane Olivia's inner core. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 301-304 (1999).

No abstract.

Rodbell, D.T., G.O. Seltzer, D.M. Anderson, M.B. Abbott, D.B. Enfield, and J.H. Newman. A high-resolution ~15,000 year record of El Niño driven alluviation in southwestern Ecuador. Science, 283(5401):516-520 (1999).

Debris flows have deposited inorganic laminae in an alpine lake 75 kilometers east of the Pacific Ocean, in Ecuador. These storm-induced events are dated by radiocarbon, and the age of laminae that are less than 200 years old matches the historic record of El Niño events. From about 15,000 to about 7,000 calendar years before the present, the periodicity of clastic deposition is greater than or equal to 15 years; thereafter, there is a progressive increase in frequency to periodicities of 2-8.5 years. This is the modern El Niño periodicity, which was established about 5,000 calendar years before present. This may reflect the onset of a steeper zonal sea surface temperature gradient, which was driven by enhanced trade winds.

Roemmich, D., O. Boebel, Y. Desaubies, H. Freeland, B. King, P.-Y. Le Traon, R.L. Molinari, W.B. Owens, S. Riser, U. Send, K. Takeuchi, and S. Wijffels. Argo: The global array of profiling floats. OCEANOBS99: International Conference on the Ocean Observing System for Climate, Saint Raphael, France, October 18-22, 1999. Centre National d'Etudes Spatiales, Vol. 1, 12 pp. (1999).

A broad-scale global array of temperature/salinity (T/S) profiling floats, known as Argo, is planned as a major component of the ocean observing system, with deployment scheduled to begin in 2000. Conceptually, Argo builds on the existing upper-ocean thermal networks, extending their spatial and temporal coverage, depth range and accuracy, and enhancing them through addition of salinity and velocity measurements. The name Argo is chosen to emphasize the strong complementary relationship of the global float array with the Jason altimeter mission. For the first time, the physical state of the upper ocean will be systematically measured and assimilated in near real time. Objectives of Argo fall into several categories. Argo will provide a quantitative description of the evolving state of the upper ocean and the patterns of ocean climate variability, including heat and freshwater storage and transport. The data will enhance the value of the Jason altimeter through measurement of subsurface vertical structure (T(z), S(z)) and reference velocity, with sufficient coverage and resolution for interpretation of altimetric sea surface height variability. Argo data will be used for initialization of ocean and coupled forecast models, data assimilation, and dynamical model testing. A primary focus of Argo is seasonal to decadal climate variability and predictability, but a wide range of applications for high-quality global ocean analyses is anticipated. The initial design of the ARGO network is based on experience from the present observing system, on newly gained knowledge of variability from the TOPEX/Poseidon altimeter, and on estimated requirements for climate and high-resolution ocean models. Argo will provide 100,000 T/S profiles and reference velocity measurements per year from about 3000 floats distributed over the global oceans at 3-degree spacing. Floats will cycle to 2000 m depth every 10 days, with a 4-5 year lifetime for individual instruments. All Argo data will be publicly available in near real-time via the GTS, and in scientifically quality-controlled form with a few months delay. Global coverage should be achieved during the Global Ocean Data Assimilation Experiment, which together with CLIVAR and GCOS/GOOS, provide the major scientific and operational impetus for Argo. The design emphasizes the need to integrate Argo within the overall framework of the global ocean observing system. International planning for Argo, including sampling and technical issues, is coordinated by the Argo Science Team. Nations presently having Argo plans that include float procurement or production include Australia, Canada, France, Germany, Japan, the U.K., and the U.S.A., plus a European Union proposal. Combined deployments from these nations may exceed 700 floats per year as early as 2001. Broad participation in Argo by many nations is anticipated and encouraged either through float procurement, logistical support for float deployment, or through analysis and assimilation of Argo data.

Roemmich, D., O. Boebel, H. Freeland, B. King. P.-Y. LeTraon, R.L. MOLINARI, W.B. Owens, S. Riser, U. Send, K. Takeuchi, and S. Wijffels. On the design and implementation of Argo: An initial plan for a global array of profiling floats. International CLIVAR Project Office Report 21, GODAE Report 5. GODAE International Project Office, Melbourne, Australia, 32 pp. (1999).

No abstract.

Rogers, R.F. Amplification of warm-core vortices by convective redevelopment: A key component of tropical cyclogenesis. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 929-932 (1999).

No abstract.

Rogers, R.F., and J.M. Fritsch. Amplification of warm-core vortices by convective redevelopment: A key component of tropical cyclogenesis. Preprints, Eighth Conference on Mesoscale Processes, Boulder, CO, June 28-July 1, 1999. American Meteorological Society, Boston, 55-60 (1999).

No abstract.

Shapiro, L.J., and J.L. Franklin. Potential vorticity asymmetries and tropical cyclone motion. Monthly Weather Review, 127(1):124-131 (1999).

A set of nine synoptic-flow cases, incorporating Omega dropwindsonde observations for six tropical storms and hurricanes, is used to deduce the three-dimensional distribution of potential vorticity (PV) that contributed to the deep-layer mean (DLM) wind that steered the cyclones. A piecewise inversion technique, the same as that previously applied by Shapiro to Hurricane Gloria of 1985, is used to derive the DLM wind induced by pieces of anomalous PV restricted to cylinders of different radii centered on each cyclone. The cylinder of PV that induces a DLM wind that best matches the observed DLM wind near the center of each cyclone is evaluated. It is found that the results can be loosely placed into two categories describing the spatial scale of the PV anomalies that influenced the cyclone's motion. Four of the cases, including Hurricane Gloria, had "local" control, with a good match (to within 40%) between the observed DLM wind near the cyclone center and the DLM wind attributable to a cylinder of PV with a given radius of 1500 km. Further decomposition of the PV anomaly into upper (400 mb and above) and lower levels (500 mb and below) indicates the dominance of upper-level features in steering two of the cyclones (Hurricanes Gloria of 1985 and Andrew of 1992), while Hurricane Debby of 1982 was steered by more barotropic features. These results supplement those found in other studies. Five of the cases, by contrast, had "large-scale" control, with no cylinder of radius 2000 km having a good match between the induced and observed DLM wind. Hurricanes Emily of 1987 and 1993 fell into this category, as did Hurricane Josephine of 1984. Implications of the results for guiding in-situ wind measurements to improve hurricane track forecasts are discussed.

Smith, N.R., D.E. Harrison, R. Bailey, O. Alves, T. Delcroix, K. Hanawa, B. Keeley, G. Meyers, R.L. Molinari, and D. Roemmich. The role of XBT sampling in the ocean thermal network. OCEANOBS99: International Conference on the Ocean Observing System for Climate, Saint Raphael, France, October 18-22, 1999. Centre National d'Etudes Spatiales, Vol. 1, 26 pp. (1999).

This paper evaluates the present role of the XBT program and proposes a strategy for the future under the assumption that there are other direct and indirect contributions to sampling the temperature and salinity of the ocean. Since the focus is on XBT sampling, the paper restricts its scope to the upper ocean, mostly above 1000 m. The conclusions of the paper are based on a study and workshop that were convened specifically to look at the design of the ship-of-opportunity network and to look at options for its implementation in the future under the assumption that Argo happens. The paper also addresses issues related to data distribution and management. The primary conclusion is that the network of the future should place greatest emphasis on line sampling, at intermediate to high densities, and assume that a proposed profiling float array, Argo, will largely take over the role formerly occupied by area (broadcast) sampling. It is argued that line sampling exclusively addresses several needs of the ocean observing system that cannot easily be addressed by other forms of sampling. Further, it is argued that such a mode complements other in-situ components such as moorings and floats, as well as remotely-sensed surface topography. A new network is outlined with a strategy for implementation that ensures continuity between existing and planned networks. We conclude the data management system that was established around the SOOP program requires substantial renovation if it is to adequately address the needs of the data gatherers and suppliers, and the data users (modelers, scientists, operational applications).

Smith, R.H. IASlinks.org: Online management and distribution of oceanographic and meteorological data for the Gulf of Mexico and Caribbean Sea. Proceedings, First Biennial Intra-Americas Sea Initiative (IASI) Science Meeting, Panama City, Panama, November 9-11, 1999. University of Miami, 41-42 (1999).

There is a growing recognition of the connectivity among oceanic processes within the Gulf of Mexico and Caribbean Sea region (Intra-Americas Sea). Recent technological breakthroughs in communication, specifically the Internet, provide a common denominator for scientific collaboration and data exchange among the region's institutions and government agencies that collect data and utilize data products. The growing need for regional scale models requires that interaction between research endeavors take place, enabling the creation of larger, regional data sets and a more unified approach to understanding the oceanography, climate, and ecology of the Intra-Americas Sea. The Internet web site, http://IASlinks.org, hosted by NOAA/AOML in Miami, Florida, has been developed to facilitate the sharing of resources, results, and data sets relevant to research conducted throughout the Intra-Americas Sea region. The site is presently designed with indices describing the different types of research and the different institutions, agencies, and personnel involved, with regular highlights of specific regional research topics; it is our hope that the site will continue to expand, becoming a more complete representation of observational programs presently underway in and around the Gulf of Mexico and Caribbean Sea. The usefulness of a venue such as IASlinks.org will continue to be realized as scientists and operational observing systems throughout the Intra-Americas Sea make more of their data available over the Internet. In particular, the Internet as a medium for data exchange will play a pivotal role in the forthcoming IOCARIBE-GOOS regional observing system. IASlinks will complement the IASI web site, which will emphasize research programs, education, and training. This collaborative atmosphere, where scientific information and resources are shared with one another, will provide investigators working in the region the ability to tackle larger questions regarding climate, circulation, the propagation of species, and the connectivity of regional marine environments.

Swenson, M.S., and D.V. Hansen. Tropical Pacific Ocean mixed-layer budget: The Pacific cold tongue. Journal of Physical Oceanography, 29(1):69-82 (1999).

Data from satellite-tracked drifting buoys and VOS/XBT profiles for the years 1979-1995 were used to evaluate the seasonal cycle of how major oceanic processes redistribute heat in the cold tongue region of the tropical Pacific. The most active processes for the annual cycle are local heat storage and heat export by entrainment of upwelling and by mean meridional advection. Heat export by zonal advection, however, is not negligible, and meridional eddy heat fluxes associated with tropical instability waves effect a negative feedback that offsets a considerable fraction of that produced by the mean meridional advection. All of these processes mimic the essentially one cycle per year of the surface wind stress, as do those of the depths of both the bottom of the surface mixed layer and the thermocline. Because it is associated with poleward Ekman transports, upwelling, and baroclinic adjustment near the equator, the zonal wind stress component appears to be the more important. The meridional wind stress, while weaker in the annual mean, has a larger annual variation and, therefore, has equal influence on the annual variation of the scalar stress and perhaps the mixed layer thickness. The Monin-Obukov length is found to underestimate the mixed layer thickness very considerably. Finally, we produce the first estimates of the seasonal cycle of eddy heat flux convergence, which plays a significant role in the evolution of the cold tongue, and show that the eddy heat flux convergence can be quantitatively modeled as eddy diffusion with a diffusivity derived from single-particle buoy statistics.

Takahashi, T., R.H. Wanninkhof, R.A. Feely, R.F. Weiss, D.W. Chipman, N. Bates, J. Olafsson, C.Sabine, and S.C. Sutherland. Net sea-air CO₂ flux over the global oceans: An improved estimate based on the sea-air pCO₂ difference. Proceedings, Second International Symposium on CO₂ in the Oceans, Tsukuba, Japan, January 18-22, 1999. Center for Global Environmental Research (CGER-I037-99), 9-15 (1999).

No abstract.

Tedesco, L.P., C. Souch, J. Pachut, J.A. Arthur, H.R. Wanless, P.L. Blackwelder, T. Hood, C. Alvarez-Zarikian, J. Trefry, W.J. Kang, S. Metz, and T.A. Nelsen. The signature of hurricane sedimentation in the lower Everglades/Florida Bay ecosystem: Recognition of sedimentologic, geochemical, and microfaunal indicators. 1999 Florida Bay and Adjacent Marine Systems Science Conference, Programs and Abstracts, Key Largo, FL, November 1-5, 1999. University of Florida Sea Grant Program, 194-195 (1999).

Winter storm and hurricane resuspension and transport processes are responsible for building the bulk of the sediment sequence in the accreting bank flanks in both northwest Oyster Bay (Whitewater Bay) and Florida Bay. Repetitive resuspension by winter storms provides fine silt-sized carbonate, siliceous and organic laminae as thin event laminae, mostly a millimeter or less in thickness. As these repetitive winter storms produce similar wind and transport sequences in an area, the constituent composition and mineralogy of the laminae are similar. Vertical profiles of excess ²¹⁰Pb activity in sediments from northwest Oyster Bay, Jimmy Key, and First National Bank showed that sedimentation at these sites has been in steady state during the last 40 years. However, two to three discontinuities of short duration (<2 years) in the decay profiles of excess ²¹⁰Pb activities were observed in the sedimentary records from northwest Oyster Bay, Jimmy Key, and First National Bank. Based on excess 210Pb-based ages, the discontinuities occurred at about 1960, 1948, and 1935, dates coincident with major hurricanes passing through Florida Bay: Donna in September 1960 (category 4); an unnamed hurricane in September 1948 (category 3); and the Great Labor Day Hurricane in September 1935 (category 5). Hurricane layers from 1935, 1948, 1960 (Donna), and 1992 (Andrew) in Oyster Bay are identified by a sharp surface on which sand-sized shell, carbonate peloids, and organic detritus are concentrated and overlain by a white, fine sand to silt layer, 0.5-2 cm in thickness. Sedimentologic and geochemical data on discontinuity surfaces show that the base of each hurricane layer is an erosional surface from which several centimeters of sediment was eroded. This is expected as the upper 3-10 cm of the sediment in these accreting flanks is a very soft zone with as much as 80% water content that could easily be removed. Discontinuities of ²¹⁰Pb profiles and, therefore, erosion were more pronounced in open water sites such as Jimmy Key and First National Bank (3-20 cm thick) relative to the more protected, mangrove coastline surrounded environment of northwest Oyster Bay (~2 cm thick). Major hurricanes (categories 4 and 5) are devastating to the red and black mangrove communities, causing destruction to 50-100% of the forest in the eye wall of the storm. This loss is reflected in the organic detritus content of sediments in cores from northwest Oyster Bay and other areas surrounded by extensive mangrove coastlines. Prior to a major hurricane, the macro-organic detritus is mainly partly decayed fragments of mangrove leaves released from the adjacent forests. Defoliation, uprooting, and death of the forest during and following the storm result in a change in the amount and composition of organic detritus in sediments. Organic detritus is composed of fine root hairs for a period of 5-10 years following the event. This reflects an extended period of erosion and release of root-hair detritus from the disrupted and decaying mangrove peat substrate. Organic detritus gradually decreases and becomes dominated by leaf detritus as the forest recovers. Hurricane-related signals in the microfaunal assemblage data (benthic ostracods and foraminifers) are both site- and event-specific. The two hurricanes that significantly modified the microfaunal assemblages from Jimmy Key and northwest Oyster Bay are the Labor Day Hurricane of 1935 and Hurricane Donna (1960). Hurricane Donna resulted in peaks in relative abundance of atypical benthic foraminifer species at both sites. At Jimmy Key, the species comprising this peak were derived from elsewhere within Florida Bay. In contrast, in northwest Oyster Bay, species were comprised of continental shelf species transported from the Gulf of Mexico by Donna's last winds. An example of hurricane-specific effects can be seen in the differing signals recorded by the 1935 and 1960 hurricanes at Jimmy Key. The 1960 hurricane left a distinct lag-type deposit, whereas the 1935 hurricane sediments were essentially barren of microfauna. High organic carbon influx and subsequent oxygen depletion associated with these hurricane events appear to be recorded in the microfaunal assemblages as well.

Thacker, W.C. Principal predictors. International Journal of Climatology, 19(8):821-834 (1999).

Principal predictors are linear combinations of variables from one set that efficiently describe the collective variability of those from a second set. Their defining eigenproblem is similar to that of canonical-correlation analysis, and when the two sets are taken to be the same, principal predictors reduce to principal components. Within the context of a forecast model for the circulation in the Gulf of St. Lawrence, they are shown to be capable of providing a low-dimensional characterization of high-resolution model dynamics.

Uhlhorn, E.W., P.G. Black, and A.F. Hasler. Evolution of mesoscale flow in a mature tropical cyclone as determined from satellite imagery. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 200-203 (1999).

No abstract.

Vachon, P.W., and K.B. Katsaros. Atmospheric cyclones from spaceborne SAR. Backscatter, 10(4):14-19 (1999).

No abstract.

Vachon, P.W., K.B. Katsaros, P.G. Black, and P.P. Dodge. RADARSAT synthetic aperture radar measurements of some 1998 hurricanes. Proceedings, 1999 International Geoscience and Remote Sensing Symposium (IGARSS '99), Hamburg, Germany, June 28-July 2, 1999. Institute of Electrical and Electronic Engineers, 1631-1633 (1999).

The RADARSAT synthetic aperture radar (SAR) acquired C-band and HH polarization images over four 1998 hurricanes: Bonnie, Danielle, Georges, and Mitch. We present the SAR images and discuss their quantitative use in understanding hurricane morphology. The SAR provides a complementary "view from below" that is most beneficial when considered in the context of more conventional hurricane observations.

Wang, C., R.H. Weisberg, and J.I. Virmani. Western Pacific interannual variability associated with the El Ni�o-Southern Oscillation. Journal of Geophysical Research, 104(C3):5131-5149 (1999).

Observations of sea surface temperature (SST), sea level pressure (SLP), surface wind, and outgoing longwave radiation (OLR) show that the El Ni�o-Southern Oscillation (ENSO) displays western Pacific anomaly patterns in addition to eastern Pacific anomaly patterns. During the warm phase of ENSO, warm SST and low SLP anomalies in the equatorial eastern Pacific and low OLR anomalies in the equatorial central Pacific are accompanied by cold SST and high SLP anomalies in the off-equatorial western Pacific and high OLR anomalies in the off-equatorial far western Pacific. Also, while the zonal wind anomalies over the equatorial central Pacific are westerly, those over the equatorial far western Pacific are easterly. The nearly out-of-phase behavior between the eastern and western tropical Pacific is also observed during the cold phase of ENSO, but with anomalies of opposite sign. These western Pacific interannual anomaly patterns are robust features of ENSO, independent of data sets. It is argued that equatorial easterly (westerly) wind anomalies over the far western Pacific during the warm (cold) phase of ENSO are initiated by off-equatorial western Pacific cold (warm) SST anomalies, and that these winds are important for the evolution of ENSO. An atmosphere model is employed to demonstrate that small off-equatorial western Pacific cold (warm) SST anomalies (compared to those in the east) are sufficient to produce equatorial easterly (westerly) wind anomalies as observed over the far western Pacific. The coupled ocean-atmosphere model of Zebiak and Cane is then modified to investigate the evolution of the western Pacific interannual anomaly patterns in a coupled ocean-atmosphere system, by including a meridional structure to the subsurface temperature parameterization in the western Pacific. The modified model produces both western and eastern Pacific interannual anomaly patterns.

Wang, C., R.H. Weisberg, and H. Yang. Effects of the wind speed-evaporation-SST feedback on the El Ni�o-Southern Oscillation. Journal of the Atmospheric Sciences, 56(10):1391-1403 (1999).

The thermodynamical process of latent heat flux is added to an analogical delayed oscillator model of the El Ni�o-Southern Oscillation (ENSO) that mainly considers equatorial ocean dynamics and produces regular, non-phase-locked oscillations. Latent heat flux affects the model sea surface temperature (SST) variations by a positive feedback between the surface wind speed and SST operating through evaporation which is called the wind speed-evaporation-SST feedback. The wind speed-evaporation-SST feedback in which the atmosphere interacts thermodynamically with the ocean through surface heat flux differs from the conventional zonal wind stress-SST feedback in which the atmosphere interacts dynamically with the ocean through momentum flux. The combination of equatorial ocean dynamics and thermodynamics produces relatively more realistic model oscillations. When the annual cycle amplitude of the zonal wind in the wind speed-evaporation-SST feedback is gradually increased, the model solution undergoes a transition from periodic to chaotic and then to periodic oscillations for some ranges of the parameters, whereas for other ranges of the parameters the transition goes from periodic to quasi-periodic and then to periodic oscillations. The route to chaos is the intermittency route. Along with such irregularity, the nonlinear interactions between the annual and interannual cycles operating through the wind speed-evaporation-SST feedback also produce a phase-locking of ENSO to the seasonal cycle. The model ENSO onset and peak occur in the boreal winter and spring, respectively, consistent with the observed phase-locking of ENSO in the far eastern Pacific. It is shown that ENSO decadal or interdecadal variability may result from the nonlinear interactions between the annual and interannual cycles in the tropics.

Wanninkhof, R.H. Recent advances in determining air-sea CO₂ fluxes. Proceedings, Second International Symposium on CO₂ in the Oceans, Tsukuba, Japan, January 18-22, 1999. Center for Global Environmental Research (CGER-I037-99), 101-104 (1999).

Uncertainties in inverse calculations to determine regional carbon fluxes between the atmospheric, oceanic, and terrestrial reservoirs (Fan et al., 1998) have clearly indicated the need to improve our oceanic carbon flux estimate. There have been significant advances in several aspects of air-sea flux determinations to address this question, including direct estimates of fluxes by co-variance and gradient measurements in the air-boundary layer, extrapolation routines using remote sensing products, and a rapidly increasing observational database of air-sea partial pressure differences. The gas fluxes are commonly expressed as F = k s DELTA-pCO₂ where F is the air-sea flux CO₂ (mol m^-2 day^-1), k is the gas transfer velocity (m day^-1), s is the solubility (mol m³ µatm^-1) and DELTA-pCO₂ is the air-water partial pressure difference (µatm). This overview discusses recent research aimed at improving estimates of F, k, and DELTA-pCO₂.

Wanninkhof, R.H., and W.M. McGillis. A cubic relationship between air-sea CO₂ and wind speed. Geophysical Research Letters, 26(13):1889-1892 (1999).

Using recent laboratory and field results we explore the possibility of a cubic relationship between gas exchange and instantaneous (or short-term) wind speed, and its impact on global air-sea fluxes. The theoretical foundation for such a dependency is based on retardation of gas transfer at low to intermediate winds by surfactants, which are ubiquitous in the world's oceans, and bubble-enhanced transfer at higher winds. The proposed cubic relationship shows a weaker dependence of gas transfer at low wind speed and a significantly stronger dependence at high wind speed than previous relationships. A long-term relationship derived from such a dependence, combined with the monthly CO₂ climatology of Takahashi (1997), leads to an increase in the global annual oceanic CO₂ uptake from 1.4 Gigaton C yr^-1 to 2.2 Gigaton C yr^-1. Although a cubic relationship fits within global bomb-¹⁴C oceanic uptake constraints, additional checks are warranted, particularly at high wind speeds where the enhancement is most pronounced.

Wanninkhof, R.H., E. Lewis, R.A. Feely, and F.J. Millero. The optimal carbonate dissociation constants for determining pCO₂ from alkalinity and total inorganic carbon. Marine Chemistry, 65(3-4):291-301 (1999).

In many numerical ocean chemistry models total dissolved inorganic carbon (DIC) and total alkalinity (TA) are transported between subsurface boxes, and partial pressure pCO₂ is calculated from TA and DIC in the surface box in order to account for air-sea exchange of carbon dioxide. The conversion is commonly performed by solving the thermodynamic relationships for equilibria between carbonate, bicarbonate, and aqueous CO₂ using apparent carbonate dissociation constants. Four independent determinations of the constants have been performed for seawater in the past 50 years. These results have been corrected, refit, and combined by others, creating a virtual cottage industry of laboratory and field verification and cross checks. Here we show that, based on extensive field observations in three major ocean basins, the calculated surface pCO₂ from TA and DIC corresponds best with the measured pCO₂ of the constants proposed by Mehrbach et al.

Wanninkhof, R.H., S. Doney, T.-H. Peng, J.L. Bullister, K. Lee, and R.A. Feely. Comparison of methods to determine the anthropogenic CO₂ invasion into the Atlantic Ocean. Tellus B, 51(2):511-530 (1999).

A comparison of different methods of estimating anthropogenic CO₂ into the Atlantic Ocean through the center of the basin between 62°N and 42°S is performed using referenced high quality total dissolved inorganic carbon (DIC) data. The specific anthropogenic input is determined utilizing analytical procedures as described in Gruber et al. (1996), and Chen and Millero (1979) to correct for remineralization and to estimate preanthropogenic endmembers. These estimates are compared with results of the Princeton ocean biogeochemical model (OBM). The results show the specific inventories of anthropogenic carbon agreeing to within 20% but with different uptake patterns. The differences are largely caused by differing assumptions about mixing and winter outcrop endmembers. The same photosynthetic quotients (Redfield ratios) were used each methods. Varying these constants within the range of literature values causes changes in specific inventories of similar magnitude as the different methodologies. Comparison of anthropogenic CO₂ uptake and chlorofluorocarbon ages, and preanthropogenic photosynthetic quotients utilizing the analytical methods suggest that anthropogenic CO₂ penetration is too shallow following the procedure according to Gruber et al. (1996), and too deep using those of Chen and Millero (1979) in the North Atlantic. The results support previous observations that the uptake of CO₂ in the North Atlantic is disproportionate to its surface area. This is caused by a combination of deep water formation and deep winter mixed layers.

Watson, A.I., K.M. Stellman, K.J. Gould, and P.P. Dodge. Local applications of the WSR-88D hourly digital precipitation product at the National Weather Service office in Tallahassee, Florida. Preprints, 29th International Conference on Radar Meteorology, Montreal, Quebec, Canada, July 12-16, 1999. American Meteorological Society, Boston, 232-235 (1999).

No abstract.

Willis, P.T. The WSR-88D tropical Z-R relationship in south Florida. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 237-240 (1999).

No abstract.

Willoughby, H.E. Hurricane heat engines. Nature, 401(6754):649-650 (1999).

No abstract.

Willoughby, H.E. Vortex tracking semispectral hurricane models. Preprints, 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 10-15, 1999. American Meteorological Society, Boston, 662-665 (1999).

No abstract.

Wilson, W.D. Atlantic western boundary currents. Proceedings, South Florida Measurement Center Workshop: Establishment of a Center for Innovative Oceanography in the 21st Century, Dania, FL, February 24-26, 1999. National Science Foundation, 131-140 (1999).

No abstract.

Wilson, W.D., E. Johns, R.H. Smith, T.N. Lee, and E. Williams. Interaction of freshwater riverine discharges from the Everglades with the Gulf of Mexico and Florida Bay: Preliminary results from a moored array and shipboard surveys. 1999 Florida Bay and Adjacent Marine Systems Science Conference, Programs and Abstracts, Key Largo, FL, November 1-5, 1999. University of Florida Sea Grant Program, 175-177 (1999).

No abstract.

Zhang, J.-Z., C.J. Fischer, and P.B. Ortner. Laboratory glassware as a contaminant in silicate analysis of natural water samples. Water Research, 33(12):2879-2883 (1999).

When glassware is used for the storage of water samples, reagents, and standard solutions, dissolution of silicate from the glass containers can contaminate the samples. Experimental results demonstrate that dissolution from glassware can introduce micromolar silicate within a few hours. The extent of dissolution depends upon contact time, salinity, and pH of the solution, and the size and shape of the containers.

Zhang, J.-Z., C.J. Fischer, and P.B. Ortner. Optimization of performance and minimization of silicate interference in continuous flow phosphate analysis. Talanta, 49(2):293-304 (1999).

Specific reaction conditions for automated continuous flow analysis of phosphate are optimized in regard to minimizing coating and silicate interference, while maintaining high sensitivity. Use of Sb in the reagent increases sensitivity and yields absorbances with little temperature dependence. Coating can be minimized by using a final solution at a pH >0.5. At final pH of 0.78, there is maximum interference from silicate in the sample. We recommend, therefore, as an optimal reaction condition with minimal silicate interference, the use of Sb, a final solution pH of 1.00, room temperature for the reaction, and a [H+]/Mo ratio of 70. An equation is provided to correct silicate interference in high precision phosphate determination. **1998**

Aberson, S.D. Five-day tropical cyclone track forecasts in the North Atlantic basin. Weather and Forecasting, 13(4):1005-1015 (1998).

Statistical analyses of the most recent 40 years of hurricane tracks (1956-1995) are presented, leading to a version of the North Atlantic climatology and persistence (CLIPER) model that exhibits much smaller forecast biases but similar forecast errors compared to the previously used version. Changes to the model involve the inclusion of more accurate historical tropical cyclone track data and a simpler derivation of the regression equations. Nonlinear systems analysis shows that the predictability timescale in which the average errors increase by a factor e is approximately 2.5 days in the Atlantic basin, which is larger than that found by similar methods near Australia. This suggests that five-day tropical cyclone track forecasts may have some benefit, and, therefore, a version of CLIPER extended to five days to be used as a baseline to measure this skill is needed.

Aberson, S.D., M.A. Bender, and R.E. Tuleya. Ensemble forecasting of tropical cyclone intensity. Preprints, Symposium on Tropical Cyclone Intensity Change, Phoenix, AZ, January 11-16, 1998. American Meteorological Society, Boston, 150-153 (1998).

No abstract.

Aberson, S.D., M.A. Bender, and R.E. Tuleya. Ensemble forecasting of tropical cyclone tracks. Preprints, 12th Conference on Numerical Weather Prediction, Phoenix, AZ, January 11-16, 1998. American Meteorological Society, Boston, 290-292 (1998).

No abstract.

Alfaro, E., L. Cid, and D.B. Enfield. Relationships between the start and end date of the rainy season in Central America and the tropical Atlantic and Pacific Oceans. Investigaciones Marinas, 26:59-69 (1998).

In recent years, several studies have shown that anomalies in the sea surface temperature of the tropical Atlantic and Pacific Oceans are related to variations in the intensity and timing of the rainy season in Central America. In order to study anomalous behavior of the rainy season over Central America, tropical Atlantic and Pacific Oceans indices are used to produce correlation series with the starting and ending date (IELL and TELL) of the rainy season. The North Atlantic (ATN) and SOI-Niño3 indices show the main correlations with the IELL and the TELL respectively.

Amat, L.R., M.D. Powell, and S.H. Houston. WANDA: HRD's real-time tropical cyclone "Wind Analysis Distributed Application." Preprints, 16th Conference on Weather Analysis and Forecasting and Symposium on the Research Foci of the U.S. Weather Research Program, Phoenix, AZ, January 11-16, 1998. American Meteorological Society, Boston, J29-J31 (1998).

No abstract.

Asher, W.E., and R.H. Wanninkhof. The effect of bubble-mediated gas transfer on purposeful dual gaseous-tracer experiments. Journal of Geophysical Research, 103(C5):10,555-10,560 (1998).

For air-water gas exchange across unbroken surfaces, the only gas-dependent parameter affecting the transfer velocity is the molecular diffusivity of the transferring species. In contrast, bubble-mediated transfer processes can cause the transfer velocity to depend on both molecular diffusivity and aqueous-phase solubility. This can complicate the analysis of data from dual-gaseous tracer gas transfer experiments. Bubble effects also complicate the estimation of transfer velocities for other gases from the transfer velocity calculated using the dual-tracer data. Herein, a method for incorporating the effects of bubble-mediated gas transfer processes on the transfer velocity is presented. This new procedure is used to analyze the data from two recent dual-tracer gas transfer experiments. Transfer velocities that include the effect of bubbles are calculated using the data from two previous oceanic dual-gaseous tracer experiments. Comparing these transfer velocities with transfer velocities calculated by neglecting the effect of bubbles shows that bubble-mediated transfer increased the transfer velocity of helium 3 by 5% at a wind speed of 10.6 m s^-1. However, when using the transfer velocities form helium 3 to calculate transfer velocities for carbon dioxide under the same conditions, including the effect of bubbles, decreases the transfer velocity of carbon dioxide by 18%. This shows that bubble-mediated transfer does not have a large effect on the analysis of dual-tracer data, but it is important in relating transfer velocities determined using helium 3 and sulfur hexafluoride to transfer velocities of more soluble gases at wind speeds above 10 m s^-1.

Asher, W.E., and R.H. Wanninkhof. Transient tracers and air-sea gas transfer. Journal of Geophysical Research, 103(C8):15,939-15,958 (1998).

This paper provides a review of the physics and chemistry associated with air-sea gas transfer of transient atmospheric trace gases and the available laboratory and field measurement techniques used to study air-water gas transfer. The mechanistic principals and their relation to the measurement techniques are used to show that the error associated with estimating air-sea transfer velocities of transient tracers from transfer velocities measured using proxy tracers can be significant if an incorrect dependence of the transfer velocity on molecular diffusivity is assumed. Bubble-mediated transfer processes are also demonstrated to have a significant effect on the parameterization of the transfer velocity.

Atakturk, S.S., and K.B. Katsaros. Estimates of surface humidity and wind speed obtained from satellite data in the stratocumulus regime in the Azores region. In Remote Sensing of the Pacific Ocean by Satellites, R.A. Brown (ed.). Southwood Press, Marrickville, Australia, 16-22 (1998).

No abstract.

Bauer, S., M.S. Swenson, A. Griffa, A.J. Mariano, and K. Owens. Eddy-mean flow decomposition and eddy-diffusivity estimates in the equatorial Pacific. Journal of Geophysical Research, 103(C13):30,855-30,872 (1998).

The ocean-atmospheric dynamics of the tropical Pacific Ocean create longitudinally coherent zonal flow () with strong meridional shear () in the large-scale mean and energetic mesoscale (O(100 km)) component. Parameterization of the effects of the mesoscale field depends on the separation of the large-scale mean and mesoscale eddy components in order to compute meaningful eddy diffusivity estimates in flow regimes that demonstrate strong currents and strong shear. Large gradients in the large-scale mean have precluded diffusivity estimation by traditional binning techniques. In this first of two publications, a method is developed for using Lagrangian data to estimate the diffusivity addressing the inhomogeneity of the mean flow. The spatially dependent estimate of the mean field is computed with a least squares bicubic smoothing spline interpolation scheme with an optimized roughness parameter which guarantees minimum energy in the fluctuation field at low frequencies. Numerical simulations based on a stochastic model of a turbulent shear flow are used to validate our approach in a conceptually simple but realistic scenario. The technique is applied to near-surface drifter observations obtained from 1979-1996 from two dynamically distinct time-space regions of the tropical Pacific Ocean. The first region, in the SEC, is characterized by a linear zonal shear mean flow and an approximately exponential autocovariance structure in the residuals. The residual velocity variance is s² ~ 130 cm² s^-2 for both components and horizontal diffusivities are 7 × 10⁷ cm² s^-1, and 3 × 10 cm² s^-1. The second region, in the NECC and the NEC, has a mean flow with a strong zonal shear and a weak northward velocity. The autocovariance is approximately exponential for the zonal component while the meridional component has a negative lobe at about 10 days probably due to the presence of instability waves. The variance is approximately tripled compared to the SEC region estimate while the meridional diffusivity estmate is nearly the same magnitude. The zonal diffusivity is estimated to be 15 × 10⁷ cm² s^-1.

Black, P.G., and L.K. Shay. Observations of tropical cyclone intensity change due to air-sea interaction processes. Preprints, Symposium on Tropical Cyclone Intensity Change, Phoenix, AZ, January 11-16, 1998. American Meteorological Society, Boston, 161-168 (1998).

No abstract.

Boebel, O., C. Duncombe Rae, S.L. Garzoli, J. Lutjeharms, P. Richardson, T. Rossby, C. Schmid, and W. Zenk. Float experiment studies interocean exchanges at the tip of Africa. EOS, Transactions, American Geophysical Union, 79(1):7-8 (1998).

No abstract.

Bosart, L.F., W.E. Bracken, J. Molinari, C.S. Velden, and P.G. Black. Environmental influences on the rapid intensification stage of Hurricane Opal (1995) over the Gulf of Mexico. Preprints, Symposium on Tropical Cyclone Intensity Change, Phoenix, AZ, January 11-16, 1998. American Meteorological Society, Boston, 105-112 (1998).

No abstract.

Bove, M.C., J.J. O'Brien, J.B. Eisner, C.W. Landsea, and X. Niu. Effect of El Niño on U.S. landfalling hurricanes, revisited. Bulletin of the American Meteorological Society, 79(11):2477-2482 (1998).

Changes in the frequency of U.S. landfalling hurricanes with respect to the El Niño-Southern Oscillation (ENSO) cycle are assessed. Ninety-eight years (1900-1997) of U.S. landfalling hurricanes are classified, using sea surface temperature anomaly data from the equatorial Pacific Ocean, as occurring during an El Niño (anomalously warm tropical Pacific waters), La Niña (anomalously cold tropical Pacific waters), or neither (neutral). The mean and variance of U.S. landfalling hurricanes are determined for each ENSO phase. Each grouping is then tested for Poisson distribution using a chi-squared test. Resampling using a "bootstrap" technique is then used to determine the 5% and 95% confidence limits of the results. Last, the frequency of major U.S. landfalling hurricanes (sustained winds of 96 kt or more) with respect to ENSO phase is assessed empirically. The results indicated that El Niño events show a reduction in the probability of a U.S. landfalling hurricane, while La Ni�a shows an increase in the chance of a U.S. hurricane strike. Quantitatively, the probability of two or more landfalling U.S. hurricanes during an El Niño is 28%, of two or more landfalls during neutral conditions is 48%, and of two or more landfalls during La Ni�a is 66%. The frequencies of landfalling major hurricanes show similar results. The probability of one or more major hurricane landfall during El Niño is 23% but is 58% during neutral conditions and 63% during La Niña.

Broecker, W.S., and T.-H. Peng. Greenhouse Puzzles. Eldigio Press, Palisades, New York, 278 pp. (1998).

No abstract.

Broecker, W.S., S.L. Peacock, S. Walker. R. Weiss, E. Fahrbach, M. Schroeder, U. Mikolajewicz, C. Heinze, R. Key, T.-H. Peng, and S. Rubin. How much deep water is formed in the Southern Ocean? Journal of Geophysical Research, 103(C8):15,833-15,843 (1998).

Three tracers are used to place constraints on the production rate of ventilated deep water in the Southern Ocean. The distribution of the water mass tracer PO₄* ("phosphate star") in the deep sea suggests that the amount of ventilated deep water produced in the Southern Ocean is equal to or greater than the outflow of North Atlantic Deep Water from the Atlantic. Radiocarbon distributions yield an export flux of water from the North Atlantic which has averaged about 15 Sv over the last several hundred years. CFC inventories are used as a direct indicator of the current production rate of ventilated deep water in the Southern Ocean. Although coverage is as yet sparse, it appears that the CFC inventory is not inconsistent with the deep water production rate required by the distributions of PO₄* and radiocarbon. It has been widely accepted that the major part of the deep water production in the Southern Ocean takes place in the Weddell Sea. However, our estimate of the Southern Ocean ventilated deep water flux is in conflict with previous estimates of the flux of ventilated deep water from the Weddell Sea, which lie in the range 1-5 Sv. Possible reasons for this difference are discussed.

Bryan, G.H., R.F. Rogers, and J.M. Fritsch. Cloud-scale resolution simulations in moist absolutely unstable layers. Preprints, Eighth Pennsylvania State University/National Center for Atmospheric Research's Mesoscale Model Users Workshop, Boulder, CO. National Center for Atmospheric Research, 59-62 (1998).

No abstract.

Butler, J.H., J.W. Elkins, S.A. Montzka, T.M. Thompson, T.H. Swanson, A.D. Clarke, F.L. Moore, D.F. Hurst, P.A. Romashkin, S.A. Yvon-Lewis, J.M. Lobert, M. Dicorleto, G.S. Dutton, L.T. Lock, D.B. King, R.E. Dunn, E.A Ray, M. Pender, P.R. Wamsley, and C. M. Volk. Nitrous oxide and halocompounds. In Climate Monitoring and Diagnostics Laboratory Summary Report No. 24 (1996-1997), D.J. Hofmann, J.T. Peterson, and R.M. Rosson (eds.). NOAA Environmental Research Laboratories, Boulder CO, 91-121 (1998).

No abstract.

Castle, R.D., R.H. Wanninkhof, J.L. Bullister, S.C. Doney, R.A. Feely, B.E. Huss, E. Johns, F.J. Millero, K. Lee, D. Frazel, D. Wisegarver, D. Greeley, F. Menzia, M. Lamb, G. Berberian, and L.D. Moore. Chemical and hydrographic profiles and underway measurements from the eastern North Atlantic during July and August of 1993. NOAA Data Report, ERL AOML-32 (PB98-131865), 82 pp. (1998).

From July 4-August 30, 1993, the National Oceanic and Atmospheric Administration's (NOAA) Ocean-Atmosphere Carbon Exchange Study (OACES) and Radiatively Important Trace Species (RITS) programs participated in an oceanographic research cruise aboard the NOAA ship Malcolm Baldrige. The objectives of the OACES component were to determine the source and sink regions of CO₂ in the equatorial and North Atlantic during the summer and to establish a baseline of total carbon inventory in the region. Data were collected from 5°S to Iceland along a nominal longitude of 20°W. This report presents only the OACES-related data from legs 1, 2A, and 2B, including hydrography, nutrients, carbon species, dissolved oxygen, total inorganic carbon, chlorofluorocarbons, total alkalinity, pH, and salinity. Included are contour plots of the various parameters and descriptions of the sampling techniques and analytical methods used in data collection.

Chen, G., B. Chapron, J. Tournadre, K.B. Katsaros, and D. Vandemark. A new look at the diurnal variation of global oceanic precipitation from the ocean TOPography EXperiment (TOPEX) and the TOPEX Microwave Radiometer (TMR). International Journal of Remote Sensing, 19(1):171-180 (1998).

New results on the diurnal variation of global oceanic precipitation are obtained by using one year's TOPEX (ocean TOPography EXperiment) and TMR (TOPEX Microwave Radiometer) data, derived from the dual-frequency (Ku and C band) capacity of the altimeter and the non-Sun-synchronous orbit of the satellite. The diurnal variation is characterized by a three-maximum structure which peaks at 00:00, 08:00, and 16:00 local time. The midnight-morning-afternoon maxima and dawn-noon-evening minima pattern seems to correlate with the results of most previous studies and to offer a unified picture of the diurnal variation of oceanic rainfall. A slight daytime (06:00-18:00) preference of oceanic precipitation appears to be significant in all seasons with the day/night ratio varying from 1.032 to 1.141 and the annual mean being 1.082. Examination of the geographical distribution of the timing of diurnal variation shows that the majority of the world oceans favor an afternoon maximum and an evening minimum. Moreover, the northern hemisphere is more coherent in reaching its maximum, while the southern hemisphere in reaching its minimum. In addition, the mechanisms responsible for the diurnal variations are discussed.

Chen, G., B. Chapron, J. Tournadre, K.B. Katsaros, and D. Vandemark. Identification of possible wave damping by rain using TOPEX and TMR data. Remote Sensing of Environment, 63(1):40-48 (1998).

A global picture of wave damping by rain (WDBR), a phenomenon familiar to seafarers for centuries, has been so far unavailable owing to the fact that neither rules nor tools exist for its systematic measurement. The situation has changed following the launch of the first dual-frequency (5.3 GHz and 13.6 GHz) radar altimeter TOPEX, along with the three-frequency (18 GHz, 21 GHz, and 37 GHz) radiometer TMR (TOPEX Microwave Radiometer). In this study, a scheme for detecting possible WDBR using TOPEX/TMR data is proposed. The geographical distribution of identified WDBR is consistent with the simultaneous presence of high sea state and intensive rainfall. Frequent occurrences of WDBR are observed in the midlatitude of the two hemispheres, particularly in the Pacific Ocean. In contrast, WDBR rarely occurs in the majority of the tropical and subtropical oceans. The global seasonality of WDBR is found to be weak as a result of the hemispheric phase opposition of sea state and rainfall in their annual variations. Knowledge of spatial distribution and temporal variation of WDBR is useful in dealing with potential systematic biases in satellite wind and wave measurements due to rain/sea interaction. It would have been interesting to compare the WDBR with coincident estimates of global rainfall from the SSM/I (Special Sensor Microwave/Imager).

Cione, J.J., and P.G. Black. Surface thermodynamic observations within the tropical cyclone inner core. Preprints, Symposium on Tropical Cyclone Intensity Change, Phoenix, AZ, January 11-16, 1998. American Meteorological Society, Boston, 141-145 (1998).

No abstract.

Cione, J.J., R.A. Neuherz, S. Raman, L.J. Pietrafesa, K. Keeter, and X. Li. The use of pre-storm boundary-layer baroclinicity in determining and operationally implementing the Atlantic Surface Cyclone Intensification Index. Boundary-Layer Meteorology, 89(2):211-224 (1998).

The lateral motion of the Gulf Stream off the eastern seaboard of the United States during the winter season can act to dramatically enhance the low level baroclinicity within the coastal zone during periods of offshore cold advection. The relative close proximity of the Gulf Stream current off the mid-Atlantic coast can result in the rapid and intense destabilization of the marine atmospheric boundary layer directly above and shoreward of the Gulf Stream within this region. This airmass modification period oftentimes precedes either wintertime coastal cyclogenesis or the cyclonic re-development of existing mid-latitude cyclones. A climatological study investigating the relationship between the severity of the pre-storm, cold advective period, and subsequent cyclogenic intensification was undertaken by Cione et al. in 1993. Findings from this study illustrate that the thermal structure of the continental airmass, as well as the position of the Gulf Stream front relative to land during the pre-storm period (i.e., 24-48 h prior to the initial cyclonic intensification), are linked to the observed rate of surface cyclonic deepening for storms that either advected into or initially developed within the Carolina-southeast Virginia offshore coastal zone. It is a major objective of this research to test the potential operational utility of this pre-storm low level baroclinic linkage to subsequent cyclogenesis in an actual National Weather Service (NWS) coastal winter storm forecast setting. The ability to produce coastal surface cyclone intensity forecasts recently became available to North Carolina State University researchers and NWS forecasters. This statistical forecast guidance utilizes regression relationships derived from a nine-season (January 1982- April 1990), 116-storm study conducted by Cione et al. (1993). During the period between February 1994 and February 1996, the Atlantic Surface Cyclone Intensification Index (ASCII) was successfully implemented in an operational setting by the NWS at the Raleigh-Durham forecast office for 10 winter storms. Analysis of these ASCII forecasts will be presented.

Doney, S.C., J.L. Bullister, and R.H. Wanninkhof. Climatic variability in upper ocean ventilation rates diagnosed using chlorofluorocarbons. Geophysical Research Letters, 25(9):1399-1402 (1998).

The chlorofluorocarbon CFC-12 (CCl₂-F₂) distributions from two occupations of a meridional hydrographic section in the eastern North Atlantic are used to describe the oceanic penetration of CFCs and change in the integrated ventilation patterns over the five years from 1988 to 1993. The CFC-12 water-column inventories increased by 30-40%, despite a slowing atmospheric growth rate (14%), because of continuing uptake by undersaturated subsurface water masses whose response is lagged by the ventilation time-scales. After removing the long-term CFC temporal trend using a tracer age based normalization technique, we observe a distinct dipole pattern in upper ocean ventilation, with reduced convection in the subpolar gyre and enhanced production of saline subtropical underwater in 1993. These differences are discussed in relation to interannual variability in atmospheric surface forcing, upper ocean anomalies, and convection patterns associated with the North Atlantic Oscillation.

Durand, P., H. Dupuis, D. Lambert, B. Bénech, A. Druilhet, K.B. Katsaros, P.K. Taylor, and A. Weill. Comparison of sea surface flux measured by instrumented aircraft and ship during SOFIA and SEMAPHORE experiments. Journal of Geophysical Research, 103(C11):25,125-25,136 (1998).

Two major campaigns (Surface of the Oceans, Fluxes and Interactions with the Atmosphere (SOFIA) and Structure des Echanges Mer-Atmosph�re, Propri�t�s des H�t�rog�n�it�s Oc�aniques: Recherche Exp�rimentale (SEMAPHORE)) devoted to the study of ocean-atmosphere interaction were conducted in 1992 and 1993, respectively, in the Azores region. Among the various platforms deployed, instrumented aircraft and ship allowed the measurement of the turbulent flux of sensible heat, latent heat, and momentum. From coordinated missions we can evaluate the sea surface fluxes from (1) bulk relations and mean measurements performed aboard the ship in the atmosphere surface layer and (2) turbulence measurements aboard aircraft, which allowed the flux profiles to be estimated through the whole atmospheric boundary layer and therefore to be extrapolated toward the sea surface level. Continuous ship fluxes were calculated with bulk coefficients deduced from inertial-dissipation measurements in the same experiments, whereas aircraft fluxes were calculated with eddy-correlation technique. We present a comparison between these two estimations. Although momentum flux agrees quite well, aircraft estimations of sensible and latent heat flux are lower than those of the ship. This result is surprising, since aircraft momentum flux estimates are often considered as much less accurate than scalar flux estimates. The various sources of errors on the aircraft and ship flux estimates are discussed. For sensible and latent heat flux, random errors on aircraft estimates, as well as variability of ship flux estimates, are lower than the discrepancy between the two platforms, whereas the momentum flux estimates cannot be considered as significantly different. Furthermore, the consequence of the high-pass filtering of the aircraft signals on the flux values is analyzed; it is weak at the lowest altitudes flown and cannot therefore explain the discrepancies between the two platforms but becomes considerable at upper levels in the boundary layer. From arguments linked to the imbalance of the surface energy budget, established during previous campaigns performed over land surfaces with aircraft, we conclude that aircraft heat fluxes are probably also underestimated over the sea.

Eads, L.J., H.A. Friedman, and D.J. Garcia. From humble beginnings as the Inner City Marine Project to selection as a National School of Excellence. Preprints, Seventh Symposium on Education, Phoenix, AZ, January 11-16, 1998. American Meteorological Society, Boston, 162-165 (1998).

The evolution of the MAST Academy (Maritime and Science Technology High School), a Dade County Magnet School of Choice, from its predecessor, the Inner City Marine Project (ICMP), is described. ICMP originated after Dade County experienced civil unrest in the Black community in 1984. At that time, Dr. Linda J. Eads, currently MAST Academy's principal, was assigned to design a program in maritime education which emphasized career exploration for minorities. The ICMP operated from the District Office of the Dade County Public Schools and targeted elementary and middle schools in the inner city with high minority populations. When the MAST Academy opened its doors in 1991, the ICMP became the MAST Academy Outreach Department which continued to provide programs for the targeted schools. The MAST Academy presently carries on the tradition of the ICMP by providing high school students with specialized marine-theme science and technology courses. In 1996, the MAST Academy was selected as a U.S. Department of Education National Blue Ribbon School of Excellence.

Ellis, G., P. Swart, M. Lutz, C. Alvarez-Zarikian, P. Blackwelder, T.A. Nelsen, H. Wanless, and J. Trefry. The stable isotope composition of foraminifera, ostracods, and organic material in a dated core from Whitewater Bay. Proceedings, 1998 Florida Bay Science Conference, Miami, Florida, May 12-14, 1998. Florida Sea Grant College Program, 2 pp. (1998).

No abstract.

Ellsberry, R.L., and F.D. Marks. U.S. Weather Research Program Hurricane Landfall Workshop Report. Technical Note, NCAR/TN-442 (National Center for Atmospheric Research, Boulder, CO), 40 pp. (1998).

No abstract.

Feely, R.A., R.H. Wanninkhof, H.B. Milburn, C.E. Cosca, M. Stapp, and P.P. Murphy. A new automated underway system for making high precision pCO₂ measurements onboard research ships. Analytica Chimica Acta, 377(2-3):185-191 (1998).

We have developed a new temperature-controlled, automated underway system for making atmospheric and surface ocean pCO₂ measurements onboard research vessels equipped with an uncontaminated seawater intake system. Uncontaminated seawater is supplied to a showerhead plexiglass equilibrator at the rate of approximately 50 liters/minute. After about 3 minutes, the air trapped in the equilibrator is equilibrated with seawater. This air is sampled six times per hour. In addition, atmospheric air is sampled three times per hour from the intake on the bow flagstaff through 3/8" Dekabon^TM tubing to the underway system. The CO₂ measurements are made with a differential, non-dispersive, infrared analyzer LiCor^TM (model 6252). The underway system operates on an hourly cycle with the first quarter of each hour devoted to calibration with three CO₂ standards, each measured for 5 minutes. A second order polynomial calibration curve is calculated from the voltage values of the standards. The remaining time in each hour is used to measure equilibrator air (15 min), bow air (15 min), and equilibrator air once again (15 min). To date, we have successfully used the underway pCO₂ system on 12 cruises of the NOAA Ship Ka'imimoana in the equatorial Pacific. The analytical precision of the system is approximately 0.3-0.4 ppm for seawater and for air.

Ffield, A., C.I. Fleurant, R.L. Molinari, and W.D. Wilson. NOAA Ship Malcolm Baldrige 1995 cruises: MB95-02, MB95-04, and MB95-07 hydrographic data. Technical Report, Lamont-Doherty Earth Observatory, LDEO-98-1, 310 pp. (1998).

No abstract.

Fleurant, C.I., and R.L. Molinari. Comparison of bottle salinity and bottle oxygen values from WHP repeat lines I7N, I1W, I8N, and I8S. International WOCE Newsletter, 33:27-29 (1998).

No abstract.

Friedman, H.A., and D.J. Garcia. Tropical cyclone public awareness programmes: Preparing for the twenty-first century. Preprints, Seventh Symposium on Education, Phoenix, AZ, January 11-16, 1998. American Meteorological Society, Boston, 166-168 (1998).

No abstract.

Garcia, D.J., H.A. Friedman, and L.J. Eads. MAST Academy outreach: Serving the community with marine theme programs. Preprints, Seventh Symposium on Education, Phoenix, AZ, January 11-16, 1998. American Meteorological Society, Boston, 169-171 (1998).

No abstract.

Godin, O.A., D. Yu. Mikhin, and D.R. Palmer. Ocean current monitoring in the coastal zone. NOAA Technical Memorandum, ERL AOML-93 (PB99-120255), 26 pp. (1998).

A new technique has recently been put forward for real-time monitoring of ocean currents in the coastal zone. The acoustic technique, called matched non-reciprocity tomography (MNT), is being developed to extend traditional ocean acoustic tomography to the coastal zone. It should provide maps of the current field extending out tens of kilometers in range and throughout the water column. These maps will have applications to several important scientific problems such as measuring ocean circulation and upwelling and monitoring global climate change. Alternative approaches for monitoring currents in the coastal zone are surveyed and their limitations when compared with the MNT approach are discussed. Non-reciprocity tomography is based on recent progress in the theory of acoustic propagation in moving media and in the use of matched-field processing to solve tomographic inverse problems. The MNT technique can be viewed as an application of matched-field processing to a judiciously selected acoustic observable that is sensitive to flow velocity, but insensitive to sound speed and bathymetric variations, and leads to robust inversions for the depth-dependence of the velocity. The development of non-reciprocity tomography is reviewed in this article in the context of extended opportunities the technique offers in monitoring ocean dynamics in the coastal zone by acoustic means. Applications of the MNT technique to problems not directly related to coastal current monitoring are also noted.

Goodwin, K.D., J.K. Schaefer, and R.S. Oremland. Bacterial oxidation of dibromomethane and methyl bromide in natural waters and enrichment cultures. Applied and Environmental Microbiology, 64(12):4629-4636 (1998).

Bacterial oxidation of ¹⁴CH₂Br₂ and ¹⁴CH₃Br was measured in freshwater, estuarine, seawater, and hypersaline-alkaline samples. In general, bacteria from the various sites oxidized similar amounts of ¹⁴CH₂Br₂ and comparatively less ¹⁴CH₃Br. Bacterial oxidation of ¹⁴CH₃Br was rapid in freshwater samples compared to bacterial oxidation of ¹⁴CH₃Br in more saline waters. Freshwater was also the only site in which methyl fluoride-sensitive bacteria (e.g., methanotrophs or nitrifiers) governed brominated methane oxidation. Half-life calculations indicated that bacterial oxidation of CH₂Br₂ was potentially significant in all of the waters tested. In contrast, only in freshwater was bacterial oxidation of CH₃Br as fast as chemical removal. The values calculated for more saline sites suggested that bacterial oxidation of CH₃Br was relatively slow compared to chemical and physical loss mechanisms. However, enrichment cultures demonstrated that bacteria in seawater can rapidly oxidize brominated methanes. Two distinct cultures of nonmethanotrophic methylotrophs were recovered; one of these cultures was able to utilize CH₂Br₂ as a sole carbon source, and the other was able to utilize CH₃Br as a sole carbon source.

Gray, J. Commentary: Major ocean programs, National Oceanic and Atmospheric Administration. Marine Technology Society Journal, 32(3):85-87 (1998).

Ocean researchers from academia and federal agencies were called together by the National Academy of Sciences (NAS)/National Research Council (NRC) to think about the large ocean research programs that exist today, their history, lessons learned, and advice for future ocean research endeavors. As a scientist and manager with the National Oceanic and Atmospheric Administration (NOAA), I was asked to contribute my thoughts regarding NOAA's role and benefits of such research programs as the World Ocean Circulation Experiment (WOCE), Joint Global Ocean Flux Study (JGOFS), GLOBal ocean ECosystem dynamics (GLOBEC), Ocean Drilling Program (ODP), Tropical Ocean and Global Atmospheric/Tropical Atmosphere Ocean array (TOGA/TAO), CLImate VARiability and predictability (CLIVAR), Ridge Interdisciplinary Global Experiment (RIDGE), Earth Sciences History (ESH), and ARCtic System Science (ARCSS). I encourage everyone to read the NAS/NRF report.

Hasler, A.F., K. Palaniappan, C. Kambhammetu, P.G. Black, E.W. Uhlhorn, and D. Chesters. High-resolution wind fields within the inner core and eye of a mature tropical cyclone from GOES 1-min images. Bulletin of the American Meteorological Society, 79(11):2483-2496 (1998).

Mesoscale wind fields have been determined for a mature hurricane with high spatial and temporal resolution, continuity, and coherency. These wind fields, near the tropopause in the inner core and at low levels inside the eye, allow the evolution of mesoscale storm features to be observed. Previously, satellite-derived winds near hurricanes have been determined only at some distance from the eye over a typical time period of 1V2 h. Hurricane reconnaissance aircraft take 30 min to 1 h to complete an inner-core pattern. With the long observation periods of these previous methods, steady-state conditions must be assumed to give a complete description of the observed region. With the advent of 1-min interval imagery, and fourfold improvement of image dynamic range from NOAA's current generation of GOES satellites, there is a new capability to measure inner-core tropical cyclone wind fields near the tropopause and within the eye, enabling mesoscale dynamical processes to be inferred. These measurements give insights into the general magnitude and structure of the hurricane vortex, along with very detailed measurements of the cloud-top wind's variations in response to convective outbursts. This paper describes the new techniques used to take advantage of the GOES satellite improvements that, in turn, allowed the above innovations to occur. The source of data for this study is a nearly continuous 12-h sequence of 1-min visible images from NOAA GOES-9 on 6 September 1995. These images are centered on Hurricane Luis with maximum winds of 120 kt (CAT4) when it was 250 km northeast of Puerto Rico. A uniform distribution of long-lived cirrus debris with detailed structure is observed in the central dense overcast (CDO), which has been tracked using the 1-min images. The derived wind field near the tropopause at approximately 15 km in the CDO region has a strong closed circulation with speeds up to 25 m s^-1, which pulses in response to the convective outbursts in the eyewall. Cloud displacements are computed at every pixel in every image, resulting in a quarter-million uVv winds in each of 488 hurricane images observed at 1- to 4-min intervals over 12 h. For analysis and presentation, these ultradense wind fields are reduced to 8- or 16-km grids using a 7-min time base by smoothing displacement vectors in space and time. Cloud structures were tracked automatically on a massively parallel processing computer, but with manual spot-checking. Manual tracking has been used to follow CDO structure over long time periods, up to 90 min for a small test sample. Cloud tracking for the wind fields presented here is accomplished using a Massively Parallel Semi-Fluid Motion Analysis (MPSMA) automatic technique. This robust deformable surface-matching algorithm has been implemented on the massively parallel Maspar supercomputer. MPSMA automatic tracking typically follows a feature for 7 min. For this time base the error of these winds is estimated to be 1.5 m s^-1. However, systematic navigation and height assignment errors in the moderately sheared hurricane environment must still be considered. Spatial and temporal smoothing of the wind field have been performed to reduce systematic navigation errors and small-scale turbulent noise. The synthesis used here to compute the wind fields gives an order of magnitude reduction in the amount of data presented compared to the amount of data processed. Longer tracking could give higher accuracy but would smooth out the smaller-scale spatial and temporal features that appear dynamically significant. The authors believe that the techniques described in this paper have great potential for further research on tropical cyclones and severe weather as well as in operational use for nowcasting and forecasting. United States and foreign policymakers are urged to augment the GOES, GMS, FY2, and Meteosat geostationary satellite systems with dual imaging systems such that 1-min observations are routinely taken.

Hendee, J.C. An expert system for marine environmental monitoring in the Florida Keys National Marine Sanctuary and Florida Bay. Proceedings, 2nd International Conference on the Coastal Environment, Cancun, Mexico, September 8-10, 1998. Computational Mechanics Publications/WIT Press, Southampton, 57-66 (1998).

The National Oceanic and Atmospheric Administration's (NOAA, U.S. Department of Commerce) Atlantic Oceanographic and Meteorological Laboratory (AOML) works cooperatively with the Florida Institute of Oceanography (FIO) in the implementation of the SEAKEYS (Sustained Ecological Research Related to Management of the Florida Keys Seascape) network, which is situated along 220 miles of coral reef tract within the Florida Keys National Marine Sanctuary (FKNMS). This network is itself actually an enhanced framework of seven Coastal-Marine Automated Network (C-MAN) stations for long-term monitoring of meteorological parameters (wind speed, wind gusts, air temperature, barometric pressure, relative humidity). To the C-MAN network, SEAKEYS adds oceanographic parameters (sea temperature, photosynthetically active radiation, salinity, fluorometry, optical density) to the stations. As a recent enhancement to the SEAKEYS network, an expert system shell is being employed to provide daily interpretations of near real-time acquired data for the benefit of scientists, fishermen, and skin divers. These interpretations are designed to be automatically emailed to Sanctuary managers and to the FIO maintainers of the network. The first set of interpretations include those dealing with environmental conditions conducive to coral bleaching. Other marine environmental interpretations are slated to follow.

Hendee, J.C., C. Humphrey, and T. Moore. A data-driven expert system for producing coral bleaching alerts. Proceedings, 7th International Conference on the Development and Application of Computer Techniques to Environmental Studies, Las Vegas, Nevada, November 10-12, 1998. Computational Mechanics Publications/WIT Press, Southampton, 139-147 (1998).

As a recent enhancement to the SEAKEYS (Sustained Ecological Research Related to Management of the Florida Keys Seascape) environmental monitoring network, an expert system shell was employed to provide daily interpretations of near real-time acquired combinations of meteorological and oceanographic parameters as they meet criteria generally thought to be conducive to coral bleaching. These interpretations were automatically posted to the World-Wide Web and emailed to Florida Keys National Marine Sanctuary managers and scientists so they could witness and study bleaching events as they might happen, and so that a model could be developed with greater precision in identifying physical factors conducive to coral bleaching. The expert system, as a model, was successful in showing that certain assumptions by experts regarding coral bleaching apparently do not hold at Sombrero Reef.

Henderson-Sellers, A., H. Zhang, G. Berz, K. Emanuel, W. Gray, C.W. Landsea, G. Holland, J. Lighthill, S.-L. Shieh, P. Webster, and K. McGuffie. Tropical cyclones and global climate change: A post-IPCC assessment. Bulletin of the American Meteorological Society, 79(1):19-38 (1998).

The very limited instrumental record makes extensive analyses of the natural variability of global tropical cyclone activities difficult in most of the tropical cyclone basins. However, in the two regions where reasonably reliable records exist (the North Atlantic and the western North Pacific), substantial multidecadal variability (particularly for intense Atlantic hurricanes) is found, but there is no clear evidence of long-term trends. Efforts have been initiated to use geological and geomorphological records and analysis of oxygen isotope ratios in rainfall recorded in cave stalactites to establish a paleoclimate of tropical cyclones, but these have not yet produced definitive results. Recent thermodynamical estimation of the maximum potential intensities (MPI) of tropical cyclones shows good agreement with observations. Although there are some uncertainties in these MPI approaches, such as their sensitivity to variations in parameters and failure to include some potentially important interactions such as ocean spray feedbacks, the response of upper-oceanic thermal structure and eye and eyewall dynamics do appear to be an objective tool with which to predict present and future maxima of tropical cyclone intensity. Recent studies indicate the MPI of cyclones will remain the same or undergo a modest increase of up to 10%-20%. These predicted changes are small compared with the observed natural variations and fall within the uncertainty range in current studies. Furthermore, the known omissions (ocean spray, momentum restriction, and possibly also surface to 300-hPa lapse rate changes) could all operate to mitigate the predicted intensification. A strong caveat must be placed on analysis of results from current GCM simulations of the "tropical-cyclone-like" vortices. Their realism, and hence prediction skills (and also that of "embedded" mesoscale models), is greatly limited by the coarse resolution of current GCMs and the failure to capture environmental factors that govern cyclone intensity. Little, therefore, can be said about the potential changes of the distribution of intensities as opposed to maximum achievable intensity. Current knowledge and available techniques are too rudimentary for quantitative indications of potential changes in tropical cyclone frequency. The broad geographic regions of cyclogenesis and, therefore, also the regions affected by tropical cyclones are not expected to change significantly. It is emphasized that the popular belief that the region of cyclogenesis will expand with the 26 C SST isotherm is a fallacy. The very modest available evidence points to an expectation of little or no change in global frequency. Regional and local frequencies could change substantially in either direction, because of the dependence of cyclone genesis and track on other phenomena (e.g., ENSO) that are not yet predictable. Greatly improved skills from coupled global ocean-atmosphere models are required before improved predictions are possible.

Hitchcock, G., G.A. Vargo, T. Lee, E. Johns, E. Williams, and J. Jurado. The influence of circulation on nutrient distributions in western Florida Bay. Proceedings, 1998 Florida Bay Science Conference, Miami, Florida, May 12-14, 1998. Florida Sea Grant College Program, 98-99 (1998).

No abstract.

Hood, T., C. Alvarez-Zarikian, P. Blackwelder, P. Swart, T.A. Nelsen, H.R. Wanless, J.H. Trefry, and L. Tedesco. The sediment record as a monitor of natural and anthropogenic changes in the lower Everglades/Florida Bay ecosystem. Proceedings, 1998 Florida Bay Science Conference, Miami, Florida, May 12-14, 1998. Florida Sea Grant College Program, 33-34 (1998).

No abstract.

Houston, S.H., and M.D. Powell. Reconstruction of surface wind fields for hurricanes affecting Florida Bay. Preprints, Second Conference on Coastal Atmospheric and Oceanic Prediction and Processes, Phoenix, AZ, January 11-16, 1998. American Meteorological Society, Boston, 241-244 (1998).

No abstract.

Houston, S.H., and M.D. Powell. Surface wind fields in hurricanes. Proceedings, Third International Symposium, Waves '97, Virginia Beach, VA, November 3-7, 1997. American Society of Civil Engineers (ASCE), 1391-1399 (1998).

No abstract.

Houston, S.H., M. Lawrence, S. Spisak, and S.T. Murillo. A verification of National Hurricane Center forecasts of surface wind speed radii in hurricanes. Preprints, Symposium on Tropical Cyclone Intensity Change, Phoenix, AZ, January 11-16, 1998. American Meteorological Society, Boston, 139-140 (1998).

No abstract.

Huang, H., R.E. Fergen, J.R. Proni, and J.J. Tsai. Initial dilution equations for buoyancy-dominated jets in current. Journal of Hydraulic Engineering, 124(1):105-108 (1998).

Initial dilution of submerged, single, round, buoyancy-dominated jets in a current is considered. Two simple semi-empirical equations, one for centerline dilution and the other for minimum surface dilution, are presented. These equations are derived based on the continuity equation for the buoyant jet flow with a hypothesis that shear entrainment and forced entrainment can be added. Available laboratory and field data are used to determine the constants in the equations. Unlike asymptotic equations which apply for the limiting flow regimes, the proposed equations span all flow regimes, from the buoyancy-dominated near field (BDNF), to the transition, and to the buoyancy-dominated far field (BDFF), providing continuous predictions for dilutions.

Jameson, A.R., A.B. Kostinski, and R.A. Black. The texture of clouds. Journal of Geophysical Research, 103(D6):6211-6220 (1998).

Using a precise definition of clustering, it is shown that in two tropical cumulus clouds, droplets appear to be bunched over distances ranging from at least a kilometer or more down to several centimeters. A statistical framework is proposed for quantifying clustering in terms of a Poisson probability mixture. While these observations require further substantiation in many different clouds, droplet clustering may play a role in diverse phenomena from the coalescence growth of raindrops to the scattering of radiation by clouds.

Kaplan, J., and M. DeMaria. Climatological and synoptic characteristics of rapidly intensifying tropical cyclones in the North Atlantic basin. Preprints, Symposiuim on Tropical Cyclone Intensity Change, Phoenix, AZ, January 11-16, 1998. American Meteorological Society, Boston, 119-123 (1998).

No abstract.

Katsaros, K.B. Microwave remote sensing with radiometers. In Remote Sensing of the Pacific Ocean by Satellites, R.A. Brown (ed.). Southwood Press, Marrickville, Australia, 13-15 (1998).

No abstract.

Landsea, C.W., and R.A. Pielke. Trends in U.S. hurricane losses, 1925-1995. Preprints, Ninth Symposium on Global Change Studies, Phoenix, AZ, January 11-16, 1998. American Meteorological Society, Boston, 210-212 (1998).

No abstract.

Landsea, C.W., J. Kaplan, and M. DeMaria. The differing roles of the large-scale environment in the intensity changes of recent Atlantic hurricanes. Preprints, Symposium on Tropical Cyclone Intensity Change, Phoenix, AZ, January 11-16, 1998. American Meteorological Society, Boston, 113-114 (1998).

No abstract.

Landsea, C.W., N. Nicholls, and J. Gill. Australian region tropical cyclones: Recent trend and interannual predictions. Preprints, Ninth Conference on Interaction of the Sea and Atmosphere, Phoenix, AZ, January 11-16, 1998. American Meteorological Society, Boston, 1-4 (1998).

No abstract.

Landsea, C.W., G.D. Bell, W.M. Gray, and S.B. Goldenberg. The extremely active 1995 Atlantic hurricane season: Environmental conditions and verification of seasonal forecasts. Monthly Weather Review, 126(5):1174-1193 (1998).

The 1995 Atlantic hurricane season was a year of near-record hurricane activity with a total of 19 named storms (average is 9.3 for the base period 1950-1990) and 11 hurricanes (average is 5.8), which persisted for a total of 121 named storm days (average is 46.6) and 60 hurricane days (average is 23.9), respectively. There were five intense (or major) Saffir-Simpson category 3, 4, or 5 hurricanes (average is 2.3 intense hurricanes) with 11.75 intense hurricane days (average is 4.7). The net tropical cyclone activity, based upon the combined values of named storms, hurricanes, intense hurricanes and their days present, was 229% of the average. Additionally, 1995 saw the return of hurricane activity to the deep tropical latitudes: seven hurricanes developed south of 25°N (excluding all of the Gulf of Mexico) compared with just one during all of 1991-1994. Interestingly, all seven storms that formed south of 20°N in August and September recurved to the northeast without making landfall in the United States. The sharply increased hurricane activity during 1995 is attributed to the juxtaposition of virtually all of the large-scale features over the tropical North Atlantic that favor tropical cyclogenesis and development. These include extremely low vertical wind shear, below-normal sea level pressure, abnormally warm ocean waters, higher than average amounts of total precipitable water, and a strong west phase of the stratospheric quasi-biennial oscillation. These various environmental factors were in strong contrast to those of the very unfavorable conditions that accompanied the extremely quiet 1994 hurricane season. The favorable conditions for the 1995 hurricane season began to develop as far back as the previous winter. Their onset well ahead of the start of the hurricane season indicates that they are a cause of the increased hurricane activity, and not an effect. The extreme duration of the atmospheric circulation anomalies over the tropical North Atlantic is partly attributed to a transition in the equatorial Pacific from warm episode conditions (El Ni�o) to cold episode conditions (La Ni�a) prior to the onset of the hurricane season. Though the season as a whole was extremely active, 1995's Atlantic tropical cyclogenesis showed a strong intraseasonal variability with above-normal storm frequency during August and October and below normal for September. This variability is likely attributed to changes in the upper-tropospheric circulation across the tropical North Atlantic, which resulted in a return to near-normal vertical shear during September. Another contributing factor to the reduction in tropical cyclogenesis during September may have been a temporary return to the near-normal SSTs across the tropical and subtropical North Atlantic, caused by the enhanced tropical cyclone activity during August. Seasonal hurricane forecasts for 1995 issued at Colorado State University on 30 November 1994, 5 June 1995, and 4 August 1995 correctly anticipated an above-average season, but underforecast the extent of the extreme hurricane activity.

Lee, K., and W.M. Sackett. The high temperature titration of biogenic silica. Deep-Sea Research, Part I, 45(6):1015-1028 (1998).

A new method has been developed for measuring biogenic silica (amorphous) in marine sediments. It is based on the Hogbom-Urey reaction CaCO₃+SiO₂ (biogenic silica)->CaSiO₃ (wollastonite)+CO₂. The reaction is carried out in evacuated sealed glass tubes with added excess reagent grade calcite at 500°C for 3 d. The product CO₂ is measured in a calibrated manometer. The dependence of the reaction on time, temperature, product CO₂ pressure, and other factors is examined.

Lee, K., R.H. Wanninkhof, T. Takahashi, S.C. Doney, and R.A. Feely. Low interannual variability in recent oceanic uptake of atmospheric carbon dioxide. Nature, 396(6707):155-158 (1998).

An improved understanding of the partitioning of carbon between the atmosphere, terrestrial biosphere, and ocean allows for more accurate predictions of future atmospheric CO₂ concentrations under various fossil-fuel CO₂ emission scenarios. One of the more poorly quantified relevant processes is the interannual variability in the uptake of fossil-fuel CO₂ from the atmosphere by the terrestrial biosphere and ocean. Existing estimates, based on atmospheric measurements, indicate that the oceanic variability is large. Here we estimate the interannual variability in global net air-sea CO₂ flux using changes in the observed wind speeds and the partial pressure of CO₂ (pCO₂) in surface seawater and the overlying air. Changes in seawater pCO₂ are deduced from interannual anomalies in sea surface temperature and the regionally and seasonally varying temperature-dependence of seawater pCO₂, assuming that variations in sea surface temperature reflect seawater pCO₂ changes caused by thermodynamics, biological processes, and water mixing. The calculated interannual variability in oceanic CO₂ uptake of 0.4 Gt C yr^-1(2 sigma) is much less than that inferred from the analysis of atmospheric measurements. Our results suggest that variable sequestration of carbon by the terrestrial biosphere is the main cause of observed year-to-year variations in the rate of atmospheric CO₂ accumulation.

Lee, T.N., E. Johns, W.D. Wilson, and E. Williams. Florida Bay circulation and exchange study. Proceedings, 1998 Florida Bay Science Conference, Miami, Florida, May 12-14, 1998. Florida Sea Grant College Program, 43-44 (1998).

No abstract.

Marks, F.D., and L.K. Shay. Landfalling tropical cyclones: Forecast problems and associated research opportunities. Preprints, 16th Conference on Weather Analysis and Forecasting and Symposium on the Research Foci of the U.S. Weather Research Program, Phoenix, AZ, January 11-16, 1998. American Meteorological Society, Boston, 520-523 (1998).

No abstract.

Marks, F.D., and L.K. Shay (and the Fifth Prospectus Development Team [PDF-5]: G. Barnes, P. Black, M. DeMaria, J. Dungan, B. McCaul, J. Molinari, M. Montgomery, M. Powell, R. Tuleya, G. Tripoli, L. Xie, and R. Zehr). Landfalling tropical cyclones: Forecast problems and associated research opportunities. Report of the Fifth Prospectus Development Team to the U.S. Weather Research Program. Bulletin of the American Meteorological Society, 79(2):305-323 (1998).

The Fifth Prospectus Development Team of the U.S. Weather Research Program was charged to identify and delineate emerging research opportunities relevant to the prediction of local weather, flooding, and coastal ocean currents associated with landfalling U.S. hurricanes specifically, and tropical cyclones in general. Central to this theme are basic and applied research topics, including rapid intensity change, initialization of and parameterization in dynamical models, coupling of atmospheric and oceanic models, quantitative use of satellite information, and mobile observing strategies to acquire observations to evaluate and validate predictive models. To improve the necessary understanding of physical processes and provide the initial conditions for realistic predictions, a focused, comprehensive mobile observing system in a translating storm-coordinate system is required. Given the development of proven instrumentation and improvement of existing systems, three-dimensional atmospheric and oceanic data sets need to be acquired whenever major hurricanes threaten the United States. The spatial context of these focused three-dimensional data sets over the storm scales is provided by satellites, aircraft, expendable probes released from aircraft, and coastal (both fixed and mobile), moored, and drifting surface platforms. To take full advantage of these new observations, techniques need to be developed to objectively analyze these observations, and initialize models aimed at improving prediction of hurricane track and intensity from global-scale to mesoscale dynamical models. Multinested models allow prediction of all scales from the global, which determine long-term hurricane motion to the convective scale, which affect intensity. Development of an integrated analysis and model forecast system optimizing the use of three-dimensional observations and providing the necessary forecast skill on all relevant spatial scales is required. Detailed diagnostic analyses of these data sets will lead to improved understanding of the physical processes of hurricane motion, intensity change, the atmospheric and oceanic boundary layers, and the air-sea coupling mechanisms. The ultimate aim of this effort is the construction of real-time analyses of storm surge, winds, and rain, prior to and during landfall, to improve warnings and provide local officials with the comprehensive information required for recovery efforts in the hardest hit areas as quickly as possible.

Mayer, D.A., and R.H. Weisberg. El Niño-Southern Oscillation-related ocean-atmosphere coupling in the western equatorial Pacific. Journal of Geophysical Research, 103(C9):18,635-18,648 (1998).

Using 43 years of Comprehensive Ocean-Atmosphere Data Set (COADS) and related data for the period 1950-1992, an examination is made into the regional dependence of ocean-atmosphere coupling in relation to the El Niño-Southern Oscillation (ENSO). The cross correlation between sea surface temperature (SST) and sea level pressure (SLP) anomalies over the global tropics shows two patterns of significant negative correlation consistent with a local hydrostatic response of SLP to SST: (1) the eastern Pacific, where the correlation is symmetric about and largest on the equator; and (2) the western Pacific, where symmetric regions of negative correlation are found off the equator, separated by a region of positive correlation on the equator. Anomalies within these two patterns vary out of phase with each other. While the SLP anomalies on both sides of the basin are of similar magnitude, the SST anomalies in the east are much larger than those in the west. Despite this disparity in the SST anomaly magnitudes between the eastern and western Pacific, we argue that the ocean-atmosphere couplings in the western and west-central Pacific are important for ENSO. The off-equator SST anomalies in the west enhance the SLP anomalies there and they appear to initiate easterly wind anomalies over the far western Pacific during the peak El Niño phase of ENSO. As these easterlies evolve, their effect upon the ocean tends to oppose that of the westerly wind anomalies found over the west-central Pacific. These competing effects suggest a mechanism that may contribute to coupled ocean-atmosphere system oscillations. The west-central equatorial Pacific (the region separating the eastern and western patterns), while exhibiting large momentum and heat flux exchanges, shows minimum correlation between SST and SLP. Thus, neither the SST and SLP anomaly magnitudes nor the correlation between them are alone indicative of ocean-atmosphere coupling, and the regional dependence for such coupling in relation to ENSO appears more complicated than mechanistic interpretations of ENSO would suggest.

Mayer, D.A., R.L. Molinari, and J.F. Festa. The mean and annual cycle of upper layer temperature fields in relation to Sverdrup dynamics within the gyres of the Atlantic Ocean. Journal of Geophysical Research, 103(C9):18,545-18,566 (1998).

Using 28 years of expendable bathythermograph data (1967-1994), we describe the mean and annual cycle of the upper ocean temperature fields in the Atlantic from 30°S to 50°N in the context of the basin-scale wind-driven gyres (Sverdrup stream function field) which provide a framework for describing the oceanographic measurements. We examine the circulation field implied by the temperature distributions which are used as a proxy for the field of mass. Similarities between the temperature and stream function fields increase with depth. In the lower to subthermocline depths of the tropical and equatorial gyres, the zonal currents form a closed circulation. A Southeastward Boundary Current is suggested near and below 150 m that provides closure for the tropical gyre, and the equatorial gyre axis is southward of that suggested by the stream function field. Higher in the water column, the North Equatorial Countercurrent (NECC) may be a surface manifestation of the North Equatorial Undercurrent (NEUC) where the latter can be interpreted as the southern limb of the tropical gyre. Because there are large vertical shears in the tropics, the equatorial gyre is not clearly indicated in the vertically integrated temperature field but appears below about 200 m. Here, the South Equatorial Undercurrent (SEUC) can be interpreted as the eastward flowing northern limb of the equatorial gyre and is opposite in direction to the westward flowing South Equatorial Current above. Both the NEUC and SEUC are analagous to currents in the Pacific that are governed by non-Sverdrup dynamics. Despite the shortcomings of the data, the mean annual cycle appears to be relatively stable, and we have discounted the possibility that in regions where it represents a significant percentage of the total variance, it is changing slowly over the 28 years of record. The wind-forcing fields, which undergo large meridional movements (5-6 of latitude) during their annual cycle, with some exceptions, have essentially no counterpart in gyre movements between their seasonal extremes. Most of the variability associated with the annual cycle is confined to the upper 300 m. Greatest variability, where ranges exceed 6°C, occurs in the northwestern Atlantic in late winter and early spring. During this time of year south of the Gulf Stream and below about 100 m, water temperatures exhibit a systematic phase lag with depth. The next largest area of variability, where ranges can also exceed 6°C, resides in the tropical western basin between the equator and 10°N just below 100 m. In the eastern basin, ranges decrease and shoal. Additionally, the phase fields are consistent with the intensification and relaxation of the tropical ridge-trough system where the NECC disappears in March in the west but the NECC/NEUC complex is strongest in September.

McElligott, S., R.H. Byrne, K. Lee, R.H. Wanninkhof, F.J. Millero, and R.A. Feely. Discrete water column measurements of CO₂ fugacity and pHT in seawater: A comparison of direct measurements and thermodynamic calculations. Marine Chemistry, 60(1-2):63-73 (1998).

The NOAA Equatorial Pacific CO₂ system data set (~2500 water samples) has been evaluated to assess the internal consistency of measurements and calculations involving CO₂ fugacity and pH_T. This assessment represents the first large scale field comparison of pH_T and fCO₂ data. Comparisons of direct discrete CO₂ fugacity (fCO₂) measurements with CO₂ fugacity calculated from total inorganic carbon (C_T), total alkalinity (A_T), and spectrophotometric pH (pH_T = -log[H⁺]_T) indicate that a variety of improvements are needed in the parameter measurements and thermodynamic relationships used to relate fCO₂, C_T, A_T, and pH_T in seawater. CO₂ fugacity calculated from C_T and pH_T or A_T and pH_T agree with direct measurements to no better than 1%. Comparisons of measured fugacity, fCO₂ (measured), and CO₂ fugacity calculated from C_T and pH_T, fCO₂ (C_T, pH_T), indicate that the precision of fCO₂ calculations is good relative to direct measurements. In contrast, due to the extreme sensitivity of fCO₂ and [H⁺]_T calculations to relatively small errors in both C_T and A_T, CO₂ fugacity, as well as [H⁺]_T, calculated from C_T and A_T are very imprecise and render comparisons with direct measurements of little use. Consequently, precise calculations of fCO₂ require the use of direct pH_T measurements.

Millero, F.J., K. Lee, and M. Roche. Distribution of alkalinity in the surface waters of the major oceans. Marine Chemistry, 60(1-2):111-130 (1998).

In recent years the total alkalinity (TA) of seawater has been measured with high precision (~ �2 µmol kg^-1) in the Atlantic, Pacific, and Indian oceans. In this paper, we have analyzed the surface alkalinity of the major ocean basins using these measurements as well as those obtained during the GEOSECS and TTO studies. The salinity normalized alkalinity (NTA=TA x 35/S) in subtropical gyres between 30°S and 30°N is remarkably invariable except in upwelling areas (e.g., the eastern equatorial Pacific). The NTA increases toward high latitudes (>40°) and is inversely proportional to sea surface temperature (SST). This increase in NTA with latitude (or decreasing temperature) is attributed to the upward transport of deep waters with higher NTA due to the dissolution of CaCO₃(s). The distribution of surface NTA in the major ocean basins shows that the major basins can be divided into regions where different trends of NTA are observed and boundaries between the regions are similar to those of the major ocean currents. The linear behavior of NTA (~ �5 µmol kg^-1) with respect to SST makes it possible to provide regional maps of NTA. These maps can be used to estimate TA in surface waters in large areas of the ocean from values of SST and salinity (S). By combining the estimates of TA using SST and S (from the Climatological Atlas of the World Ocean) with underway fCO₂ measurements (by ships, moorings, and satellites), it is possible to map the detailed distribution of TCO₂ for surface waters over a large area of the ocean. Calculations of TCO₂ from measurements of fCO₂, SST, and S in the subtropical Pacific Ocean agree with the coulometrically measured values to �5 µmol kg^-1.

Millero, F.J., W. Yao, K. Lee, J.-Z. Zhang, and D.M. Campbell. Carbonate system in the waters near the Galapagos Islands. Deep-Sea Research, Part II, 45(6):1115-1134 (1998).

During the IRONEX cruise in the equatorial Pacific Ocean, the carbonate parameters TA (total alkalinity), TCO₂ (total inorganic carbon), pH, and fCO₂ (fugacity of CO₂), were determined both in a small (8 × 8 km) patch of water fertilized with Fe and in the waters around the Galapagos Islands. The CO₂ parameters, along with hydrographic properties, were found to be uniform in the surface waters of the study area before the addition of iron. A significant decrease of the surface TCO₂ (7 �mol kg^-1) and fCO₂ (11 �atm) in the patch was detected within 48 h of the iron release. This decrease, however, did not continue and was lower than expected from the complete utilization of NO₃^- due to the addition of iron. The shipboard iron a ddition experiments (3 nM fe) resulted in a continual decrease of TCO₂ (up to 48 �mol kg^-1) and complete consumption of the nutrients. A good correlation was found between TCO₂, pH, and fCO₂ with temperature in the surface waters around the Galapagos Islands. The salinity (S = 35) normalized alkalinities were quite uniform (NTA = 2310 � 9 mol kg^-1) throughout the region. The effect of high primary production on the CO₂ system in the downstream plume is overshadowed by the upwelling waters with high CO₂.

Millero, F.J., D.G. Purkerson, P. Steinberg, E. Peltola, K. Lee, C. Edwards, J. Goen, and M.P. Roche. The carbon dioxide system in the Ross Sea during the JGOFS Southern Ocean Process Study. University of Miami Technical Report, RSMAS-98-001, 159 pp. (1998).

In the austral summer of 1996 and austral fall of 1997, we participated in the Joint Global Ocean Flux Study (JGOFS) supported by the National Science Foundation (NSF) in the Southern Ocean aboard the R/V Nathaniel B. Palmer. The first cruise was a survey across the Antarctic Convergence Zone from Port Lyttelton, New Zealand to the Ross Sea and back. The Process 1 and 3 cruises were in the Ross Sea. The first process cruise originated in Port Lyttelton, New Zealand and ended in McMurdo Station, Antarctica. The third process cruise originated and ended in Port Lyttelton, New Zealand. This report gives the results of our pH, total alkalinity (TA), and total inorganic carbon dioxide (TCO₂) measurements made during these cruises. The pH, TCO₂, and TA results were obtained by potentiometric titration of seawater samples with hydrochloric acid (HCl), while the TCO₂ was determined by coulometry. Spectroscopic pH measurements were also made. Measurements of pH, TA, and TCO₂ were made on certified reference material (CRM) throughout the cruises to assess the quality of the measurements. The reproducibility of these CRM measurements by potentiometric titration were ±1.6 µmol kg^-1 in TA, ±2.2 µmol kg^-1 in TCO₂, and ±0.005 in pH. The reproducibility in TCO₂ by coulometry were ±1 µmol kg^-1 and ±0.001 in the spectroscopic values of pH. The at sea measurements agreed with the assigned values of ±2 µmol kg^-1 in TA, ±5 µmol kg^-1 in TCO₂, and ±0.002 in pH. All the measurements done at sea were adjusted for these differences. The values of pH, TA, and TCO₂ for the measurements in the Ross Sea are examined for the process studies along with surface nutrients and pCO₂.

Millero, F.J., A.G. Dickson, G. Eischeid, C. Goyet, P. Guenther, K.M. Johnson, R.M. Key, K. Lee, D. Purkerson, C.L. Sabine, R.G. Schottle, D.R.W. Wallace, E. Lewis, and C.D. Winn. Assessment of the quality of the shipboard measurements of total alkalinity on the WOCE hydrographic program Indian Ocean CO₂ survey cruises, 1994-1996. Marine Chemistry, 63(1-2):9-20 (1998).

In 1995, we participated in a number of WOCE Hydrographic Program cruises in the Indian Ocean as part of the Joint Global Ocean Flux Study (JGOFS) CO₂ survey sponsored by the Department of Energy (DOE). Two titration systems were used throughout this study to determine the pH, total alkalinity (TA), and total inorganic carbon dioxide (TCO₂) of the samples collected during these cruises. The performance of these systems was monitored by making closed cell titration measurements on Certified Reference Materials (CRMs). A total of 962 titrations were made on six batches of CRMs during the cruises. The reproducibility calculated from these titrations was ±0.007 in pH, ±4.2 µmol kg^-1 in TA, and ±4.1 µmol kg^-1 in TCO₂. The at-sea measurements on the CRMs were in reasonable agreement with laboratory measurements made on the same batches. These results demonstrate that the CRMs can be used as a reference standard for TA and to monitor the performance of titration systems at sea. Measurements made on the various legs of the cruise agreed to within 6 µmol kg^-1 at the 15 crossover points. The overall mean and standard deviation of the differences at all the crossovers are 2.1 ± 2.1 µmol kg^-1. These crossover results are quite consistent with the overall reproducibility of the CRM analyses for TA (±4 µmol kg^-1) over the duration of the entire survey. The TA results for the Indian Ocean cruises provide a reliable data set that, when combined with TCO₂ data, can completely characterize the carbonate system.

Molinari, J., S. Skubis, D. Vollaro, F. Alsheimer, and H.E. Willoughby. Potential vorticity analysis of tropical cyclone intensification. Journal of the Atmospheric Sciences, 55(6):2632-2644 (1998).

The interaction of marginal Tropical Storm Danny (1985) with an upper-tropospheric positive potential vorticity anomaly was examined. The intensification mechanism proposed earlier for mature Hurricane Elena appears to be valid for Danny as well, despite significant differences in the synoptic-scale environment and in the stage of the tropical cyclone prior to the interaction. Both storms experienced rapid pressure falls as a relatively small-scale positive upper potential vorticity anomaly began to superpose with the low-level tropical cyclone center. The interaction is described in terms of a complex interplay between vertical wind shear, diabatic heating, and mutual advection among vortices at and below the level of the outflow anticyclone. Despite this complexity, the superposition principle appears to be conceptually useful to describe the intensification of tropical cyclones during such interactions.

Molinari, R.L., H.F. Bezdek, M. Latif, and A. Groetzner. A comparison of modeled and observed mean and decadal time-scale Atlantic air-sea structure. Proceedings, Atlantic Climate Variability Meeting, Palisades, New York, September 24-26, 1997. University Corporation for Atmospheric Research, 78-79 (1998).

No abstract.

Molinari, R.L., R.A. Fine, W.D. Wilson, R.G. Curry, J. Abell, and M.S. McCartney. The arrival of recently formed Labrador Sea Water in the Deep Western Boundary Current at 26.5°N. Geophysical Research Letters, 25(13):2249-2252 (1998).

The Deep Western Boundary Current (DWBC) of the North Atlantic is a principal conduit between the formation region for Labrador Sea Water (LSW) and the oceanic interior to the south. Time series (1985-1997) of hydrographic properties obtained in the DWBC at 26.5°N show that prior to 1994, temperature, salinity, and transient tracer properties within the LSW density range showed little indication of recently formed parcels. Properties characteristic of a newer version of LSW (cooler, fresher, and higher tracer concentrations) were observed beginning in 1994 and continuing through 1997. Longer time series of temperature and salinity, developed from a regional data base, show both the 1994 and a 1980-1981 event in the Abaco region. Both events are consistent with anomalies in the Labrador Sea that occurred some 10 years earlier. The 10-year transit time from the Labrador Sea to 26.5°N is less than the 18-year transit time inferred from earlier studies.

Montgomery, M.T., and J.L. Franklin. An assessment of the balance approximation in hurricanes. Journal of the Atmospheric Sciences, 55(12):2193-2200 (1998).

The validity of the traditional balance approximation for the asymmetric flow above the boundary layer generally in hurricanes is examined here. Scaling considerations of the divergence equation show that the validity of the balance approximation hinges on the smallness of the nondimensional product. The first term represents the ratio of asymmetric horizontal divergence to asymmetric vertical vorticity for azimuthal wavenumber, n, while the second term represents a Rossby number based upon the azimuthal mean tangential wind and absolute vertical vorticity of the hurricane vortex. Wind observations of Hurricane Gloria (1985) indicate that this product is not at all small in the near-vortex region (several hundred kilometers beyond the radius of maximum tangential winds) where asymmetric convergence forced by surface friction and cumulus convection is typically large. Although the Gloria observations represent only a single case, there are dynamical reasons to expect this product to be 0(1) just above the hurricane boundary layer in steadily translating hurricanes. The meteorological relevance of these results to the problem of balance dynamics in hurricanes is briefly discussed.

Murphy, P.P., R.A. Feely, and R.H. Wanninkhof. On obtaining high-precision measurements of oceanic pCO₂ using infrared analyzers. Marine Chemistry, 62(1-2):103-115 (1998).

Assessments of ocean carbon uptake using the air-sea disequilibrium of CO₂ require very high quality measurements of pCO₂ in the atmosphere and in surface seawater. These measurements are often collected and analyzed using infrared detectors. Laboratory data are presented here which suggest that errors of the order of several parts per million in xCO₂ can result if the analyzer temperature and pressure are not carefully matched during calibration and sampling. Field data were examined to address questions about the importance of measuring analysis temperature and pressure under more extreme conditions, sample averaging, and calibration frequency. The results indicate that calibration frequency can be minimized without significant compromises in data quality if the analyzer temperatures and pressures are suitably monitored and/or controlled. Daily calibrations gave results to within 0.4 ppm of the results obtained by hourly calibration when the temperature of the analyzer was controlled to �0.2°C and the voltages were corrected for pressure differences between calibration and sampling.

Nicholls, N., C.W. Landsea, and J. Gill. Recent trends in Australian region tropical cyclone activity. Meteorology and Atmospheric Physics, 65(3-4):197-205 (1998).

The number of tropical cyclones observed in the Australian region (south of equator; 105-160°E) has apparently declined since the start of reliable (satellite) observations in the 1969/1970 season. However, the number of more intense cyclones (with minimum pressures dropping to 970 hPa or lower) has increased slightly. The numbers of weak (minimum pressures not dropping below 990 hPa) and moderate systems (minimum pressures between 970 and 990 hPa) have declined. Possible reasons for these different trends are discussed. The decline in the number of weaker cyclones may at least partly reflect improved understanding of the nature of some weak systems. The decline in the number of cyclones more intense than 990 hPa primarily reflects the downward trend in the Southern Oscillation Index (SOI). Previous work has demonstrated that the number of tropical cyclones observed in the Australian region each cyclone season is related to the value of the SOI prior to the start of the cyclone season. This relationship is clearest with the number of moderate cyclones. The SOI is only weakly related to the number of intense or weak cyclones. The increase in the number of intense cyclones is not attributable to the trend in the SOI. Nor is there clear reason, at present, to suspect that it is artificial (i.e., due to changes in observing or analysis techniques).

Niyogi, D.S., J.J. Cione, and S. Raman. Gulf Stream influence on the North Carolina mesoclimate. Preprints, 2nd Conference on Coastal Atmospheric and Oceanic Prediction, Phoenix, AZ, January 12-16, 1998. American Meteorological Society, Boston, 421-424 (1998).

No abstract.

Ortner, P.B., M.J. Dagg, G.S. Kleppel, R. Brenner, and C. Tomas. Trophic pathways in the pelagic environment of Florida Bay. Proceedings, 1998 Florida Bay Science Conference, Miami, Florida, May 12-14, 1998. Florida Sea Grant College Program, 143-145 (1998).

No abstract.

Ozgokmen, T.M., and O.E. Esenkov. Asymmetric fingers induced by the nonlinear equation of state. Physics of Fluids, 10(8):1882-1890 (1998).

The impact of the nonlinearity in the equation of state associated with the change in the thermal expansion coefficient with temperature on the structure of fingers growing from an interface between two mixed layers is investigated using a numerical model. It is shown that the nonlinearity acts to enhance the buoyancy force acting on the descending fingers with respect to that acting on the ascending fingers, resulting in narrower and faster-growing descending fingers than ascending fingers. The results are discussed with emphasis on the vertical variability of properties along the fingers.

Ozgokmen, T.M., O.E. Esenkov, and D.B. Olson. A numerical study of layer formation due to fingers in double-diffusive convection in a vertically-bounded domain. Journal of Marine Research, 56(2):463-487 (1998).

The evolution of fingers in a double-diffusive system is investigated using numerical integration of two-dimensional equations of motion for an incompressible, Boussinesq fluid. The computational domain is periodic in the horizontal direction and is closed with no-flux boundary conditions in the vertical direction. The main result of this study is the evolution of the system from initially linear profiles for both fast and slow diffusing components to a layered state characterized by a finger zone sandwiched between two mixed layers. The horizontal boundaries in this system play an important role in the development of the layered state. At the top and bottom boundaries, light and heavy finger fluxes accumulate leading to the formation of mixed layers exhibiting larger-scale eddies. In the quasi-equilibrium state, the finger zone is characterized by broken wiggly fingers which do not extend across the entire interface. The salinity flux at the mid-depth of the domain is approximately proportional to the 4/3 power of the salinity difference between the mixed layers, except for the initial phase and for the run-down phase.

Peltola, E., R. Wanninkhof, R. Molinari, B.E. Huss, R. Feely, J. Bullister, J.-Z. Zhang, F. Chavez, A. Dickson, A. Ffield, D. Hansell, F. Millero, P. Quay, R. Castle, G. Thomas, R. Roddy, T. Landry, M. Roberts, H. Chen, D. Greeley, K. Lee, M. Roche, J.A. Goen, F. Millero, K. Buck, M. Kelly, F. Menzia, A. Huston, T. Waterhouse, S. Becker, and C. Mordy. Chemical and hydrographic measurements during the Indian Ocean I8 repeat cruise (IR8N) in September and October 1995. NOAA Data Report, ERL AOML-34 (PB99-126948), 176 pp. (1998).

This document contains data and metadata from the I8 repeat cruise in the Indian Ocean cruise in 1995 from Fremantle, Australia to Male in the Maldives. From September 22 to October 25, 1995, the National Oceanic and Atmospheric Administration (NOAA) sponsored an oceanographic research cruise conducted aboard the NOAA Ship Malcolm Baldrige. This report presents the analytical and quality control procedures and data from the cruise that was conducted for the Ocean-Atmosphere Carbon Exchange Study (OACES). Samples were taken at 101 stations. The data presented in this report includes hydrography, nutrients, total dissolved inorganic carbon dioxide (DIC), fugacity of carbon dioxide (fCO₂), total alkalinity (TA), pH, total organic carbon and nitrogen data (TOC/TON), chlorofluorocarbons, ¹³C, and biological parameters.

Peng, T.-H., R. Key, and H.G. Ostlund. Temporal variations of bomb radiocarbon in the Pacific Ocean. Marine Chemistry, 60(1-2):3-14 (1998).

The natural and anthropogenic components of the radiocarbon measurements from seawater samples can be successfully separated by an improved method, which is based on a very well-defined relationship between natural radiocarbon and dissolved silica observed mainly during the GEOSECS survey for waters beneath 1000 m depth. This relationship is further reconfirmed by the ¹⁴C measurements from large volume samples taken in the deep waters in the Pacific Ocean during the recent WOCE survey program. Analysis of upper ocean ¹⁴C measurements made along 152°W, and north of 20°'N, in the northeastern Pacific Ocean during the NOAA's CGC91 cruise, which is a part of the WOCE survey program, indicates that the bomb ¹⁴C inventory in this part of the ocean has increased by 22% since the GEOSECS measurements made in 1974. This increase is consistent with the model prediction of 25% for the northern hemisphere ocean. Change of the surface water bomb ¹⁴C values during this period is insignificant. This feature is also consistent with the model simulation. Results of this new analysis will provide useful information of the temporal variations of bomb ¹⁴C inventory in the ocean, in addition to the spatial distribution, which can be used as powerful constraints in calibrating the global ocean carbon cycle models, especially those based on three dimensional ocean general circulation models, for estimating the uptake of CO₂ by the ocean.

Peng, T.-H., R.H. Wanninkhof, J.L. Bullister, R.A. Feely, and T. Takahashi. Quantification of decadal anthropogenic CO₂ uptake in the Indian Ocean based on dissolved inorganic carbon measurements. Nature, 396(6711):560-563 (1998).

The increase of total dissolved inorganic carbon (DIC) in the ocean caused by the uptake of fossil fuel CO₂ is estimated mostly by ocean models. These model estimates need to be verified using field measurements. However, the direct detection of the anthropogenic CO₂ signal in the ocean has been hampered by the relatively small annual increase in DIC in seawater (~1 �mol/kg/yr, as compared with background DIC of ~2000 �mol/kg) and by lack of high-precision measurements in the past. With the recent improvement in DIC analyses techniques, it has now become possible to detect the anthropogenic CO₂ signal on decadal time scales. Here we report a significant increase in DIC between the GEOSECS survey in 1978 and the recent NOAA-OACES survey in 1995 in the Indian Ocean. The anthropogenic CO₂ signal is 12 � 4.5 �mol/kg at ~300 m (potential density, sigma_theta = 26.6) and the signal decreases on denser isopycnal horizons down to undetectable near ~1000 m (sigma_theta = 27.2). The data are used to illustrate the isopycnal analysis and corrections necessary to determine the anthropogenic CO₂ increase over time. The work can be used as a guide for future observational strategies to assess uptake of anthropogenic CO₂.

Pielke, R.A., and C.W. Landsea. Normalized hurricane damages in the United States: 1925-1995. Weather and Forecasting, 13(3):621-631 (1998).

Hurricanes are the costliest natural disasters in the United States. Understanding how both hurricane frequencies and intensities vary from year to year, as well as how this is manifested in changes in damages that occur, is a topic of great interest to meteorologists, public and private decision makers, and the general public alike. Previous research into long-term trends in hurricane-caused damage along the U.S. coast has suggested that damage has been quickly increasing within the last two decades, even after considering inflation. However, to best capture the year-to-year variability in tropical cyclone damage, consideration must also be given toward two additional factors: coastal population changes and changes in wealth. Both population and wealth have increased dramatically over the last several decades and act to enhance the recent hurricane damages preferentially over those occurring previously. More appropriate trends in the United States hurricane damages can be calculated when a normalization of the damages are done to take into account inflation and changes in coastal population and wealth. With this normalization, the trend of increasing damage amounts in recent decades disappears. Instead, substantial multidecadal variations in normalized damages are observed: the 1970s and 1980s actually incurred less damages than in the preceding few decades. Only during the early 1990s does damage approach the high level of impact seen back in the 1940s through the 1960s, showing that what has been observed recently is not unprecedented. Over the long term, the average annual impact of damages in the continental United States is about $4.8 billion (1995 $), substantially more than previous estimates. Of these damages, over 83% are accounted for by the intense hurricanes (Saffir-Simpson categories 3, 4, and 5), yet these make up only 21% of the U.S.-landfalling tropical cyclones.

Powell, M.D., and S.D. Aberson. How well do we forecast the position and time of hurricane landfall? Preprints, 16th Conference on Weather Analysis and Forecasting and Symposium on the Research Foci of the U.S. Weather Research Program, Phoenix, AZ, January 11-16, 1998. American Meteorological Society, Boston, 9-12 (1998).

No abstract.

Powell, M.D., and S.H. Houston. Surface wind fields of 1995 Hurricanes Erin, Opal, Luis, Marilyn, and Roxanne at landfall. Monthly Weather Review, 126(5):1259-1273 (1998).

Hurricanes Erin, Opal, Luis, Marilyn, and Roxanne were the most destructive hurricanes of 1995. At landfall, Luis and Marilyn contained maximum sustained winds (marine exposure) estimated at near 60 and 46 m s^-1, respectively. The strongest landfalling storm of the 1995 season, Luis, decreased in intensity from a category 4 to 3 on the Saffir-Simpson scale shortly before the eyewall crossed the Islands of Antigua, Barbuda, St. Kitts-Nevis, St. Barthelemy, St. Martin, and Anguilla. Hurricane Marilyn strengthened as it approached the U.S. Virgin Islands, with St. Thomas bearing the brunt of the north and south eyewall winds of 46 m s^-1 (marine exposure) and St. Croix being affected by the relatively weak western eyewall peak winds of 35-40 m s^-1 (marine exposure). For Luis and Marilyn, only surface winds with marine exposures were analyzed because of unknown small-scale interactions associated with complex island terrain with 500-1000-m elevations. Wind engineering studies suggest that wind acceleration over blunt ridges can increase or "speed up" winds by 20%-80%. Topographic effects were evident in damage debris analyses and suggest that an operational method of assessing terrain-induced wind gusts (such as a scaled down mesoscale model) is needed. After landfall as a marginal hurricane over central Florida, Hurricane Erin regained strength over the Gulf of Mexico with a well-defined radar reflectivity structure. Erin struck the Florida panhandle near Navarre Beach with maximum sustained surface winds of 35-40 m s^-1 affecting the Destin-Ft. Walton area. Hurricane Opal made landfall in nearly the identical area as Erin, with maximum sustained surface winds of 40-45 m s-1, having weakened from an intensity of nearly 60 m s-1 only 10 h earlier. Opal was characterized by an asymmetric structure that was likely related to cold front interaction and an associated midlevel southwesterly jet. Roxanne struck Cozumel, Mexico, with sustained surface winds (marine exposure) of 46 s^-1, crossed the Yucatan, and meandered in the southwest Gulf of Mexico for several days. While in the Bay of Campeche, Roxanne's large area of hurricane-force winds disabled a vessel, which led to the drowning deaths of five oil industry workers. High-resolution wind records are critical to preserving an accurate extreme wind climatology required for assessment of realistic building code risks. Unfortunately, power interruptions to Automated Surface Observing Stations (ASOS) on the U.S. Virgin Islands (St. Croix, St. Thomas) and Destin, Florida, prevented complete wind records of the eyewall passages of Marilyn and Opal, respectively.

Powell, M.D., and S.K. Rinard. Marine forecasting at the 1996 centennial olympic games. Weather and Forecasting, 13(3):764-782 (1998).

A team of meteorologists from the United States, Canada, and Australia provided marine weather support to the sailing events of the 1996 Centennial Olympic Games, held in Wassaw Sound near Savannah, Georgia. The team conducted research on the weather and climate and developed a set of forecast products designed to inform athletes, volunteers, and race managers of the wind, tidal current, wave, and weather behavior expected each day during the pre-Olympic and Olympic periods. The Olympic period proved to be a challenge with thunderstorms delaying, abandoning, or postponing races on half of the days. Thunderstorm development and movement was linked to the timing and strength of the sea breeze as well as the direction and speed of the gradient wind. Numerous thunderstorm warnings were issued with the assistance of the WSR-88D radar and the Warning Decision Support System. Frequent lightning was a legitimate safety concern due to the long distances between race courses and lack of suitable shelter; fortunately no one was injured during the lightning episodes. Forecasters benefited from access to a variety of monitoring tools and models including real-time Olympic buoy wind and current time series displays; satellite and radar imagery animation; 2-, 8-, and 10-km resolution mesoscale models; a live video feed of race coverage; and communications with forecasters aboard patrol craft offshore. Official wind forecasts, mesoscale models, and a simple vector addition model performed better than climatology and persistence as defined by mean vector error and rms wind direction error. Climatology was difficult to beat on the basis of wind speed error.

Powell, M.D., S.H. Houston, L.R. Amat, and N. Morisseau-Leroy. The HRD real-time hurricane wind analysis system. Journal of Wind Engineering and Industrial Aerodynamics, 77&78:53-64 (1998).

The HRD real-time wind analysis system is currently undergoing evaluation in the operational forecasting environment of the National Hurricane Center. The system is an object-oriented, distributed, three-tiered client-server application that assimilates disparate observations and processes the data into a common framework for exposure, height, and averaging time. The data are then examined collectively or by type, quality controlled, and passed on to a scale-controlled objective analysis algorithm. Several products are derived from the analysis wind field and storm track, yielding effective tools for disaster assessment, emergency management, and recovery.

Proni, J.R., and J.C. Wilkerson. Underwater acoustic monitoring for satellite rainfall estimation validation. Proceedings, 6th International Conference for Precipitation, Mauna Lani Bay, HI, June 29-July 1, 1998. NASA/NOAA, 2-10 (1998).

Application of underwater acoustic techniques to the monitoring of rainfall over water is demonstrated at four acoustically distinct ocean sites based on information in the 4-30 kHz frequency band. Rainfall detection and classification as to type (convective or stratiform) are possible because underwater sound spectral characteristics of rain are different from the normally prevailing underwater background noise in the ocean, and because there are distinct differences in the sound levels and spectral shapes of the acoustic signature of the two rain types. Rain type classification is determined by an acoustic discriminant, D_R, which is defined as the difference in the average spectral levels between the 10-30 and 4-10 kHz bands. Rainfall estimation potential is based on the high correlation between sound spectral levels in decibels (in the 4-10 kHz frequency band) and radar reflectivity dBz. Data obtained from a spatially distributed 12-hydrophone array on the ocean floor, at a depth of 1.5 km, demonstrates the potential of monitoring rainfall at the sea surface on spatial (420 km²) and temporal (five samples/minute) scales suitable for validating precipitation estimates from remote sensors carried on geostationary and polar orbiting satellites.

Proni, J.R., and J.C. Wilkerson. Wind-generated acoustic spectral effects in the surf zone in the presence and absence of rainfall at Duck, North Carolina. Proceedings, 16th International Congress on Acoustics and 135th Meeting of the Acoustical Society of America, Seattle, Washington, June 20-26, 1998. Journal of the Acoustical Society of America, 103(5):2865-2866 (1998).

Concurrent underwater sound, wind, radar, and rainfall measurements were made on November 5, 1992, off Duck, North Carolina. A wind speed increment from 5 m/s to 13 m/s in 90 seconds resulted in a reduction in the rainfall sound spectrum level beginning at about 50 kHz and extending downward in frequency with time to about 10 kHz. The reduction in rainfall-generated sound spectrum level with time is thought to be due to sound absorption by the evolving wind-generated bubble field.

Proni, J.R., C. McArthur, and G. Schuster. Adaptive dredged material discharge for the Port of Miami. Proceedings, Ports '98, Long Beach, California, March 8-11, 1998. American Society of Civil Engineers, 1249-1257 (1998).

In a joint effort of the U.S. Army Corps of Engineers, the U.S. Environmental Protection Agency, the National Oceanic and Atmospheric Administration, the State of Florida, the Port of Miami, and the University of Miami, a novel, environmentally adaptively controlled procedure was developed, wherein a vital port expansion and maintenance dredging operation was carried out while affording maximum protection to sensitive coral reefs. After establishing the existence and spatial disposition of a residual water column discharge plume, via acoustic backscattering methods, a real-time current measurement system was established at the offshore dredged material disposal site to be utilized. Dredged material discharges then proceeded on a schedule in conformity with the ambient currents, so that material transport to the coral reefs of concern was minimized.

Quilfen, Y., B. Chapron, T. Elfouhaily, K.B. Katsaros, and J. Tournadre. Observations of tropical cyclones by high-resolution scatterometry. Journal of Geophysical Research, 103(C4):7767-7786 (1998).

Unprecedented views of surface wind fields in tropical cyclones (hereafter TCs) are provided by the European Remote Sensing Satellite (ERS) C-band scatterometer. Scatterometer measurements at C band are able to penetrate convective storms clouds, observing the surface wind fields with good accuracy. However, the resolution of the measurements (50 × 50 km²) limits the interpretation of the scatterometer signals in such mesoscale events. The strong gradients of the surface wind existing at scales of a few kilometers are smoothed in the measured features such as the intensity and location of the wind maxima and the position of the center. Beyond the ERS systems, the scatterometers on-board the ADEOS and METOP satellites, designed by the Jet Propulsion Laboratory and by the European Space Agency, respectively, will be able to produce measurements of the backscattering coefficient at about 25 × 25 km² resolution. A few sets of ERS-1 orbits sampling TC events were produced with an experimental 25 × 25 km² resolution. Enhancing the resolution by a factor of 2 allows location of the wind maxima and minima in a TC with a much better accuracy than at 50 km resolution. In addition, a better resolution reduces the geophysical noise (variability of wind speed within the cell and effect of rain) that dominates the radiometric noise and, hence, improves the definition of the backscattering measurements. A comprehensive analysis of the backscattering measurements in the case of high winds and high sea states obtained within TCs is proposed in order to refine the interpretation of the wind vector derived from a backscattering model that is currently only calibrated up to moderate winds (<20 m/s) in neutral conditions. Observations of the TOPEX-POSEIDON dual-frequency altimeter are also used for that purpose. Patterns of the surface winds in TCs are described and characteristic features concerning asymmetries in the maximum winds and in the divergence field are discussed.

Rogers, S.M., and S.H. Houston. Hurricane surge and wave conditions: Research needs. Proceedings, Third International Symposium, Waves '97, Virginia Beach, VA, November 3-7, 1997. American Society of Civil Engineers, 1414-1424 (1998).

For many years, coastal engineers have recognized the importance of reliable wave height and frequency information in the design of major coastal structures. Over time, research by government agencies, such as the U.S. Army Corps of Engineers and NOAA, and private interests such as the offshore oil industry has made a substantial investment in wave gages, wave hindcasting, and wave forecasting. Design needs for breakwaters, jetties, coastal protection, offshore oil facilities, and similar large-scale projects have driven the acquisition of better wave data. Our ability to optimize design wave conditions has improved significantly and with ongoing research is likely to continue to improve in the future. Most designers and researchers would expect wave data is most important for large coastal projects. However, in the United States the most frequent application of design wave conditions is for the design of single family homes and other coastal buildings. Each day hundreds of coastal buildings in communities around the U.S. begin construction in Coastal High Hazard Areas (or V-zones) as identified by the National Flood Insurance Program (NFIP) and the Federal Emergency Management Agency (FEMA). The NFIP prepares flood hazard maps specifying minimum flood elevation standards that include wave height predictions during a 100-year storm surge, generally occurring during a hurricane or other severe coastal storm. The NFIP uses several relatively simple models for shoreline erosion, wave setup, wave runup and depth-limited linear waves. Given the uncertainties inherent in any 100-year surge model, the simple models are not unreasonable, including the use of depth limited, linear waves. For many years we have been measuring water marks along the coast following severe coastal storms with the goal of measuring the storm surge, still water elevation, and/or wave height maximum. This paper will report on case studies of U.S. hurricanes from U.S. hurricanes describing the discrepancies between even the most reliable still water marks and the lower limit of wave damage at the same locations. It is reassuring that our ability to predict offshore wave conditions has improved. However, it is clear that we have little understanding of the water-levels and wave conditions during hurricanes where we need them the most; that is, flooded building sites that are normally dry land. Some of the discrepancies can be explained by measurement errors, wave setup, wave runup, and localized setup in confined spaces and other factors, but no rational theory can explain local variations. In short, we may have a good wave gage record somewhere offshore and many post-storm water marks, but we have little idea what water elevations and wave conditions occurred in flooded building sites near the beach.Two problems result. First, small buildings are usually designed to avoid waves by being elevated on piling foundations. Without a reasonable understanding of the wave conditions, buildings will be improperly elevated for cost-effective designs (i.e., either too high or too low). A second potentially more serious problem is that the high water marks will eventually be used to calibrate the underlying storm surge models on which all design conditions are based. Our lack of understanding increases the risk of improperly calibrating the storm surge models, which are also used to predict flood elevations much further inland than those areas affected by waves. The authors believe that there is a substantial need for wave and water-level measurements near coastal building sites which are flooded during hurricanes and other design-level storms. The frequent application of wave predictions is to design cost-effective, storm-resistant buildings. The deployment of multiple, self contained wave gages at preselected sites near coastal buildings that are expected to be flooded during a landfalling hurricane is now a practical research goal with recent improvements in instrumentation. It is time to stop guessing the wave and water-level conditions and produce some real measurements.

Roubicek, A.J., S.L. Garzoli, P.L. Richardson, C.M. Dumcombe Rae, and D.M. Fratantoni. Benguela Current Experiment, R/V Seward Johnson Cruise SJ9705, Cape Town, September 4, 1997-Recife, September 30, 1997. NOAA Data Report, ERL AOML-33 (PB98-164775), 215 pp. (1998).

The main objective of this program is to study the pathways, velocity, transport, and variability of the Benguela Current and its extension with emphasis on tracking floats in the intermediate water. It is expected that the results of this program will make a significant contribution towards the understanding of inter-ocean (Indian to Atlantic) and inter-basin (South and North Atlantic) exchange of intermediate water and its role in heat and mass exchanges. This program is a component of KAPEX (Cape of Good Hope Experiment), a joint U.S., German, and South African experiment. In March 1997, a German cruise on the Polarstern led by W. Zenk and O. Boebel launched 35 RAFOS floats and five sound sources (including one of the U.S. sources near 20°S, 4°E) in the general area west and southwest of Cape Town. During August 1997, a U.S. cruise on the R/V Seward Johnson led by T. Rossby launched three sound sources east and southeast of Cape Town; 50 RAFOS floats will be launched in the Agulhas Current starting in November 1997. During the Benguela Current Experiment cruise on the RV Seward Johnson in September 1997, 32 RAFOS floats and two sound sources were launched in the general area west and northwest of Cape Town. During KAPEX, over 100 RAFOS floats and nine sound sources will measure ocean trajectories for the first time in the Agulhas Current, in its rings which enter the South Atlantic, and in the Benguela Current and its extension, which is the source of water moving northward through the Atlantic in the meridional overturning circulation cell. In addition, temperature, salinity, and velocity profiles will document the water mass and velocity structure of the Benguela Current, its extension, and several Agulhas rings.

Shapiro, L.J., and S.B. Goldenberg. Atlantic sea surface temperatures and tropical cyclone formation. Journal of Climate, 11(4):578-590 (1998).

It has long been accepted that interannual fluctuations in sea surface temperature (SST) in the Atlantic are associated with fluctuations in seasonal Atlantic basin tropical cyclone frequency. To isolate the physical mechanism responsible for this relationship, a singular value decomposition (SVD) is used to establish the dominant covarying modes of tropospheric wind shear and SST, as well as horizontal SST gradients. The dominant SVD mode of covarying vertical shear and SST gradients, which comprises equatorially confined near-zonal vertical wind shear fluctuations across the Atlantic basin, is highly correlated with both equatorial eastern Pacific SST anomalies (associated with El Ni�o) and west African Sahel rainfall. While this mode is strongly related to tropical storms, hurricanes, and major hurricane frequency in the Atlantic, it is not associated with any appreciable Atlantic SST signal. By contrast, the second SVD mode of covarying vertical shear and horizontal SST gradient variability, which is effectively uncorrelated with the dominant mode, is associated with SST fluctuations concentrated in the main tropical cyclone development region between 10°N and 20°N. This mode is significantly correlated with tropical storm and hurricane frequency but not with major hurricane frequency. Statistical tests confirm the robustness of the mode, and lag correlations and physical reasoning demonstrate that the SST anomalies are not due to the developing tropical cyclones themselves. Anomalies of SST and vertical shear during years where the mode has substantial amplitude confirm the resemblance of the individual fields to the modal structure, as well as the association of hurricane development with the warmer SSTs. Although SSTs are of secondary importance to vertical shear in modulating hurricane formation, explaining only 10% of the interannual variability in hurricane frequency over the 50% explained by vertical shear, the results support the conclusion that warmer SSTs directly enhance development. The lack of correlation with major hurricanes implies that the underlying SSTs are not a significant factor in the development of these stronger systems.

Shay, L., G.J. Goni, F.D. Marks, J.J. Cione, and P.G. Black. Role of warm ocean features on intensity change: Hurricane Opal. Preprints, Symposium on Tropical Intensity Change, Phoenix, AZ, January 11-16, 1998. American Meteorological Society, Boston, 131-138 (1998).

No abstract.

Swart, P., K.S. White, D.B. Enfield, P. Milne, and R.E. Dodge. Stable oxygen isotopic composition of corals from the Gulf of Guinea as indicators of periods of extreme precipitation conditions in the sub-Sahara. Journal of Geophysical Research, 103(C12):27,885-27,891 (1998).

Analyses of scleractinian coral skeletons from the Gulf of Guinea in the eastern Atlantic reveal that the corals from this region can be used to identify periods of severe drought and above average precipitation in the Subsahara. Data presented in this paper show a positive correlation between the magnitude of the Sahel drought and the d18O values of the Principe coral skeleton. The explanation for this positive correlation is that the salinity of the Gulf of Guinea is strongly influenced by the outflow of the Niger and Zaire Rivers. The outflow of these rivers is also correlated with the fluorescence of the Principe coral. These periods of high freshwater input correlate with periods of higher rainfall in the Subsahara and have affected the d18O values of the coral skeleton. The correlations between Principe coral d18O values and Atlantic NATL (r = -0.34), the dipole (r = -0.45), and the latitudinal position of the ITCZ (r = -0.37) illustrate that the d18O values in the Principe coral reflect climate dynamics of the region that affect the precipitation patterns in the Subsahara.

Thomas, G.G., R. Benway, S.K. Cook, Y.-H. Daneshzadeh, and W.S. Krug. Surface salinity and temperature from ships of opportunity. Proceedings, Ocean Community Conference '98, Baltimore, MD, November 16-19, 1998. Marine Technology Society, 160-165 (1998).

Thermosalinograph (TSG) data collected aboard both NOAA research vessels and ships participating in the National Oceanic and Atmospheric Administration's (NOAA) Volunteer Observing Ship (VOS) program plays an important role in the study of meridional circulation in the world's oceans. Sea surface temperature (SST) and sea surface salinity (SSS) are valuable measurements in our attempt to understand the interaction between the world's oceans and global climate. The ability to collect and calibrate these data sets to insure a high standard of data quality is necessary to validate their use in NOAA's Global Ocean Observing System (GOOS) Center data base at the Atlantic Oceanographic and Meteorological Laboratory (AOML) located in Miami, Florida.

Valdimarsson, H., S.-A. Malmberg, and M.H. Bushnell. SVP drifters in Icelandic waters, 1995-1997: Preliminary results. Technical Session, 13th Data Buoy Cooperation Panel Meeting, La Reunion, October 1997. DBCP Technical Publication 12, 91-101 (1998).

No abstract.

Wang, C., and R.H. Weisberg. Climate variability of the coupled tropical-extratropical ocean atmosphere system. Geophysical Research Letters, 25(21):3979-3982 (1998).

Observations show that tropical and extratropical Pacific SST anomalies vary out-of-phase, and that the atmospheric meridional Hadley and zonal Walker Circulations are related to these variations. A tropical-extratropical model is constructed to show oscillations consistent with observations. The positive feedback introduced by the Walker Circulation causes tropical warming so that the air rises and flows toward the subtropics where it sinks. When the sinking air approaches the sea surface, it flows both equatorward and poleward enhancing tropical easterly and extratropical westerly winds, respectively. Enhanced extratropical westerlies increases wind speed and hence evaporation, resulting in extratropical cooling. The Walker and Hadley Circulations thus result in tropical warming and extratropical cooling, respectively. The tropical warming and extratropical cooling increase the meridional SST difference and hence the meridional heat transport which erodes the tropical warming and extratropical cooling. Enhanced tropical easterlies due to the Hadley Circulation cools the tropical ocean through ocean dynamics. These negative feedbacks help the system to switch from warm to cold phases, and vice versa.

Wang, C., and R. H. Weisberg. Observations of meridional scale frequency dependence in the coupled tropical ocean-atmosphere system. Journal of Geophysical Research, 103(C2):2811-2816 (1998).

It is generally observed in models of the coupled tropical ocean-atmosphere system that the meridional scales for oscillations at interannual periods are larger than an oceanic equatorial Rossby radius of deformation. Using nine years of the high-resolution Optimum Interpolation sea surface temperature (SST) product of the NOAA/NCEP, analyses are made on the frequency dependence of the observed meridional scales, with emphasis on the latitudinal structures in the central Pacific at 140°W. On the relatively short intraseasonal and seasonal time scales the SST variations are found to occur over a meridional scale of the oceanic equatorial Rossby radius of deformation suggested by conventional equatorially trapped wave theory. In contrast to this, on the longer annual and interannual time scales the meridional scales are found to increase beyond the oceanic equatorial Rossby radius of deformation. A physical explanation for this meridional scale increase with decreasing frequency in the coupled tropical ocean-atmosphere system is discussed.

Wanninkhof, R.H., and R.A. Feely. fCO₂ dynamics in the Atlantic, Pacific, and South Indian Oceans. Marine Chemistry, 60(1-2):15-31 (1998).

Subsurface fugacities of CO₂ (fCO₂(20)) can be used in combination with total dissolved inorganic carbon (DIC) to precisely calculate total alkalinity. Thus, it can be used to determine dissolution of calcium carbonate (hard tissue) and remineralization of organic material (soft tissue), to quantify saturation constants of calcite and aragonite in seawater, and to characterize water masses. fCO₂(20) is a good tracer of biological transformation since it is thermodynamically related to the other inorganic carbon system parameters and it has a dynamic range from 200 to 2000 �atm in the world's ocean. Precision of fCO₂ measurements is better than 0.3% and the values are well calibrated using compressed gas reference standards. Increases of fCO₂(20) are observed as the water masses age during movement from the Atlantic to the Indian and South Pacific Oceans. As an example of the determination of the ratio of soft tissue remineralization to hard tissue dissolution from fCO₂(20) and DIC, the trends along the 27.2 isopyncal for the subtropical gyres of the three basins are investigated. Little CaCO₃ dissolves along this isopycnal in the Atlantic and the South Pacific while the soft tissue remineralization to hard tissue dissolution ratio in the Indian Ocean is 4.5:1. The difference in this ratio along the 27.2 isopycnal appears to be a combination of the calcite and aragonite saturation levels and the supply of aragonite tests.

White, S.R., J.D. McFadden, and J.L. Franklin. Atmospheric observations with the NOAA Gulfstream IV-SP. Preprints, 10th Symposium on Meteorological Observations and Instrumentation, Phoenix, AZ, January 11-16, 1998. American Meteorological Society, Boston, 38-41 (1998).

No abstract.

Willoughby, H.E. Tropical cyclone eye thermodynamics. Monthly Weather Review, 126(12):3053-3067 (1998).

In intense tropical cyclones, sea level pressures at the center are 50-100 hPa lower than outside the vortex, but only 10-30 hPa of the total pressure fall occurs inside the eye between the eyewall and the center. Warming by dry subsidence accounts for this fraction of the total hydrostatic pressure fall. Convection in the eyewall causes the warming by doing work on the eye to force the thermally indirect subsidence. Soundings inside hurricane eyes show warm and dry air aloft, separated by an inversion from cloudy air below. Dewpoint depressions at the inversion level, typically 850-500 hPa, are 10-30 K rather than the 100 K that would occur if the air descended from tropopause level without dilution by the surrounding cloud. The observed temperature and dewpoint distribution above the inversion can, however, be derived by 100 hPa of undilute dry subsidence from an initial sounding that is somewhat more stable than a moist adiabat. It is hypothesized that the air above the inversion has remained in the eye since it was enclosed when the eyewall formed and that it has subsided at most a few kilometers. The cause of the subsidence is the enclosed air's being drawn downward toward the inversion level as the air below it flows outward into the eyewall. Shrinkage of the eye's volume is more than adequate to supply the volume lost as dry air is incorporated into the eyewall or converted to moist air by turbulent mixing across the eye boundary. The moist air below the inversion is in thermodynamic contact with the sea surface. Its moisture derives from evaporation of seawater inside the eye, frictional inflow of moist air under the eyewall, and from moist downdrafts induced as condensate mixes into the eye. The moist air's residence time in the eye is much shorter than that of the dry air above the inversion. The height of the inversion is determined by the balance between evaporation, inflow, and inward mixing on one hand and loss to the eyewall updrafts on the other.

Zegowitz, V., and S.K. Cook. World Meteorological Organization-Volunteer Observing Ship Program. Proceedings, Ocean Community Conference '98, Baltimore, MD, November 16-19, 1998. Marine Technology Society, 6 pp. (1998).

As one of our astute, well-informed political figures said recently, "What do we need the Weather Service for, we have the Weather Channel!" Just where DOES the data come from to make a good marine forecast? Even those of you who have wandered here by mistake are about to be exposed to a little bit of information about a big contributor to this process, the World Meteorological Organization (WMO) Voluntary Observing Ship (VOS) program.

Zhang, J.-Z., and P.B. Ortner. Effect of thawing conditions on the recovery of reactive silicic acid from frozen natural water samples. Water Research, 32(8):2553-2555 (1998).

A method for thawing frozen samples for silicic acid analysis is recommended. The maximum recovery of silicic acid is achieved by thawing the frozen samples in a refrigerator (at 4°C) in the dark for at least four days. This method significantly improves the recovery of silicic acid from frozen fresh water samples. It also permits close to 100% recovery of reactive silicic acid from frozen seawater samples even after three months storage. **1997**

Aberson, S.D. Adaptive observations in a hurricane environment. Preprints, 22nd Conference on Hurricanes and Tropical Meteorology, Ft. Collins, CO, May 19-23, 1997. American Meteorological Society, Boston, 308-309 (1997).

No abstract.

Aberson, S.D. The prediction of the performance of a nested barotropic hurricane track forecast model. Weather and Forecasting, 12(1):24-30 (1997).

Linear multiple regression and discriminant analyses provide estimates of the errors of track forecasts from a nested barotropic hurricane track forecast model (VICBAR), which was run in the North Atlantic Basin during the 1989-94 hurricane seasons. Predictors are determined from the synoptic situation, the magnitude of atmospheric changes in the environment of the tropical cyclone, the consistency between current and past predictions, and the past performance of the model for each particular storm. This technique distinguishes cases in which VICBAR performs well from those for which it performs poorly and can provide skillful operational predictions of model performance to forecasts.

Acero-Schertzer, C.E., D.V. Hansen, and M.S. Swenson. Evaluation and diagnosis of surface currents in the NCEP ocean analyses. Journal of Geophysical Research, 102(C9):21,037- 21,048 (1997).

Ensemble average currents from the 15 m depth level of the NCEP analyses of the tropical Pacific Ocean are evaluated against surface mixed layer current observations obtained from an extensive set of satellite-tracked drifting buoys. These averages display many climatological characteristics of the region, but are not intended to serve as a climatology because the data from the analyses are trimmed to match the time-space distribution of the observations. Substantial discrepancies between the analyses and the observations are revealed. First, the near-equatorial meridional currents and divergence have approximately twice the magnitude in the analyses as in the observations. This discrepancy is largely independent of whether temperature profile data are assimilated or not, and is attributed to the parameterization of vertical viscosity. Second, the zonal flow in both the NECC and the SEC is much stronger in the analyses than in the observations, especially in the western Pacific. This discrepancy is associated with assimilation of temperature profile data. It arises because salinity is an active variable in the underlying analysis model, but is not controlled by boundary fluxes or other observations. Under the uncontrolled influence of advection and strong horizontal diffusion, the salinity distribution becomes nearly homogeneous. Consequently, the analyses do not account for observed temperature-salinity correlations when density is computed following assimilation of temperature profile data. This leads to erroneous pressure gradients that drive excessively strong geostrophic currents and force large accelerations near the western boundary. Our results indicate that it is important to consider the consequences on the density structure of neglecting salinity during the assimilation of temperature data. We recommend that surface salinity observations from drifting buoys and volunteer observing ships be initiated to improve the ocean analyses.

Baringer, M.O., and J.F. Price. Mixing and spreading of the Mediterranean Outflow. Journal of Physical Oceanography, 27(8):1654-1677 (1997).

Hydrographic and expendable current profiler (XCP) data taken during the Gulf of Cadiz Expedition on September 21-27, 1988 were analyzed to diagnose the mixing, spreading, and descent of the Mediterranean Outflow. The theta/S properties and the thickness and width of the outflow were very similar to that seen in earlier surveys (for example, by Heezen and Johnson, 1969). The transport of pure Mediterranean water (S=38.4) was estimated to be about half a Sv, which is considerably lower than historical estimates, most of which were indirect, but comparable to other recent estimates made from direct velocity observations. The total outflow transport was about 0.7 Sv at the west end of the Strait of Gibraltar, and increased to about 1.9 Sv within the western Gulf of Cadiz. This increase in transport occurred by entrainment of fresher North Atlantic Central Water (NACW), and the salinity anomaly of the outflow was rapidly eroded. The velocity-weighted salinity decreased to 36.7 within 60 km of the Strait, during the initial descent of the continental slope, and decreased by about another 0.1 before the deeper portion of the outflow began to float off of the bottom near Cape St. Vincent. Entrainment appears to have been correlated with the occurrence of bulk Froude numbers slightly greater than 1. In the western Gulf of Cadiz, where entrainment was much weaker, Froude numbers were well below 1. The outflow began in the eastern Strait of Gibraltar as a narrow (10 km wide) current having a very narrow range of theta/S properties (theta varies by < 0.5°C). The outflow broadened as it descended the continental slope of the northern Gulf of Cadiz, and reached a maximum width of 90 km in the western Gulf of Cadiz. The descent of the outflow was very asymmetric: the offshore and downslope edge of the flow descends rapidly, while the onshore and shallower edge of the outflow descends slowly. The northern, nearshore side remained considerably higher in the water column and thus entrained relatively warm and salty NACW. This caused the outflow to develop horizontal theta/S variability and, by about 100 km downstream, the across-stream variation in temperature on an isopycnal was more than 2°C. Much of the volume transport in the western Gulf of Cadiz was contained in two preferred modes, often called cores, apparently because of topographic steering effects. The deeper, offshore core had a central sigma_theta = 27.8, and the shallower nearshore core, which was still in contact with the bottom in the Gulf of Cadiz, had a central sigma_theta = 27.5.

Baringer, M.O., and J.F. Price. Momentum and energy balance of the Mediterranean Outflow. Journal of Physical Oceanography, 27(8):1678-1692 (1997).

Hydrographic and expendable current profiler (XCP) data taken during the Gulf of Cadiz Expedition in September 1988 were analyzed to describe some aspects of the dynamics of the Mediterranean Outflow. During the initial descent of the continental slope, the outflow current executes a 90 degrees right turn that appears to be approximately inertial. The estimated geostrophic velocity greatly underestimated the actual current, and the estimated curvature Rossby number is about 0.5. A form of the Bernoulli function was evaluated to infer the total stress (entrainment stress and bottom drag) acting on the outflow. Total stress was as large as 5 Pa where the outflow begins to descend the continental slope and where currents were in excess of 1 m/s. The entrainment stress, estimated independently from property fluxes, reached a maximum of only about 1 Pa, which was less than the inferred bottom stress. By about 100 km downstream, the current was aligned approximately along the topography. The current amplitude and the estimated stress were much less, about 0.3 m/s and less than 0.5 Pa. The entrainment stress was very small in the region well downstream of the Strait. Bottom stress thus appears to be the crucial element in the dynamics of the Mediterranean Outflow, allowing or causing the outflow to descend some 1000 m into the North Atlantic. In the regions of strongest bottom stress the inferred drag coefficient was about 3 × 10^{- 3}. Entrainment stress was much smaller by comparison, but the entrainment effect upon the density anomaly was crucial in eroding the density anomaly of the outflow.

Barnston, A.G., M. Chelliah, and S.B. Goldenberg. Documentation of a highly ENSO-related SST region in the equatorial Pacific. Atmosphere-Ocean, 35(3):367-383 (1997).

A new ENSO SST index is documented that is strongly correlated to the core ENSO phenomenon. The SST anomaly in much of the east-central and eastern tropical Pacific is closely related to ENSO. However, the anomaly from approximately the centre of the eastern half of the equatorial Pacific westward to near the date line is suggested to be most strongly ENSO-related when data spanning the most recent several decades are used. This is the case both with respect to the (1) strength of association with other oceanic/atmospheric ENSO-related anomalies (both simultaneously and as a time-delayed predictand), and (2) impact on remote worldwide climate anomalies. This observational insight was lacking in the early 198Os when the four "Ni�o" regions were developed. While a firmer dynamical foundation for this regional preference still needs to be established, the region straddling Ni�o 3 and Ni�o 4 may be regarded as an appropriate general SST index of the ENSO state by researchers, diagnosticians, and forecasters. A dataset of this index, called "Ni�o 3.4" (5°N-5°S, 120-170°W) is maintained on the Internet, shown in the Climate Diagnostics Bulletin, and provided in the Appendix of this note.

Black, M.L., R.W. Burpee, and F.D. Marks. The asymmetric distribution of vertical motions and precipitation in the hurricane eyewall. Preprints, 22nd Conference on Hurricanes and Tropical Meteorology, Ft. Collins, CO, May 19-23, 1997. American Meteorological Society, Boston, 100-101 (1997).

No abstract.

Black, M.L., J.F. Gamache, H.E. Willoughby, C.E. Samsury, F.D. Marks, and R.W. Burpee. Airborne radar observations of shear-induced asymmetries in the convective structure of Hurricane Olivia (1994). Proceedings, 28th Conference on Radar Meteorology, September 9-12, 1997, Austin, TX. American Meteorological Society, Boston, 577-578 (1997).

No abstract.

Black, P.G., J.R. Proni, J.C. Wilkerson, and C.E. Samsury. Oceanic rainfall detection and classification in tropical and subtropical mesoscale convective systems using underwater acoustic methods. Monthly Weather Review, 125(9):2014-2042 (1997).

Measurements of the underwater sound produced by rain were made at three U.S. coastal sites in a study to determine the feasibility and limitations of the acoustic detection and classification of rainfall over water. In the analysis of the rain sound spectra, concurrent radar reflectivity observations were used to identify convective and stratiform regions of the precipitating clouds overhead. It was found that acoustic classifications of rainfall as to type, based on information in the 4-30 kHz frequency band, were in general agreement with radar-derived classifications. The classification technique is based on use of an acoustic discriminant, D_R, defined as the difference in average spectral levels between the 10-30 kHz and 4-10 kHz bands. A high correlation was found between sound spectrum levels (in dB) in the 4-10 kHz frequency band and radar reflectivity, dBZ, suggesting the possible use of the 4-10 kHz band sound spectral level as a classification tool in the same way that radar reflectivity is used in classifying precipitation. Our results demonstrate the feasibility of the acoustic method for detecting and classifying rainfall at sea.

Black, R.A. Giant raindrops observed from large aircraft. Preprints, 22nd Conference on Hurricanes and Tropical Meteorology, Ft. Collins, CO, May 19-23, 1997. American Meteorological Society, Boston, 494-495 (1997).

No abstract.

Boebel, O., C. Schmid, and W. Zenk. Flow and recirculation of Antarctic Intermediate Water across the Rio Grande Rise. Journal of Geophysical Research, 102(C9):20,967-20,986 (1997).

The flow of the low-salinity Antarctic Intermediate Water (AAIW) at 700-1150 m depth across the Rio Grande Rise and the lower Santos Plateau is studied under the auspices of the World Ocean Circulation Experiment (WOCE) in the context of the Deep Basin Experiment. Our data set consists of several hydrographic sections, a collection of 15 RAFOS float trajectories, and records from 14 moored current meters. The data were gathered during different intervals between 1990 and 1994. The inferred flow field strongly supports a basinwide anticyclonic recirculation cell in the subtropical South Atlantic underneath the wind-driven gyre. Its center, which appears to be southeast of the Rio Grande Rise, separates the eastward advection of AAIW below the South Atlantic Current from the westward flowing, recirculating AAIW. The two near-shelf limbs closing the circumference of AAIW flow are formed in the east by the deep Benguela Current, potentially modulated by salty inflow of Indian Ocean Intermediate Water, and in the west by the Brazil Current system. Further important circulation elements are the Brazil-Falkland (Malvinas) Confluence Zone at 40°S and an unnamed divergence at 28°S close to the 1000 m isobath. The resulting broad southward flow of AAIW augments the share of modified, i.e., saltier, intermediate water in the source region of the South Atlantic Current, while the smaller northward flow marks the source of a narrow equatorward Western Intermediate Boundary Current, ultimately leaving the South Atlantic. This shelf-trapped jet is clearly documented in hydrographic data from 19°S and in nearby current meter records. The jet contrasts a sluggish flow across this latitude east of 35°W. A continuous flow of AAIW from its subpolar region in the southwestern Argentine Basin all along the western slope toward the equator appears unlikely between 35°S and 25°S.

Bringi, V.N., K.Knupp, A. Detwiler, L. Liu, I.J. Caylor, and R.A. Black. Evolution of a Florida thunderstorm during the Convection and Precipitation Experiment: The case of August 9, 1991. Monthly Weather Review, 125(9):2131-2160 (1997).

The relationships among kinematic, microphysical, and electric field properties within a multicell Florida thunderstorm are investigated using observations from three Doppler radar (one with multiple wavelength and polarization diversity capabilities), four instrumented penetrating aircraft, a surface-based electric field mill network, and other observation facilities. The storm was convectively active for about 1 h and at least five primary cells developed within the storm during this time, one of which went through three consecutive development cycles. The updrafts in this storm were 2-4 km wide, exhibited bubble-like evolution, and had lifetimes of 10-20 min. The maximum updraft determined by the multiple Doppler analysis was about
20 m s^-1. A differential reflectivity (Z_DR) "column," indicating regions containing millimeter-size raindrops, extending above the freezing level, was associated with each cell during its developing stages. This column reached altitudes exceeding 6 km (-8°C) in the stronger updrafts. As the Z_DR columns reached maximum altitude, a "cap" of enhanced linear depolarization ratio (LDR) and enhanced 3-cm wavelength attenuation (A3) formed, overlapping the upper regions of the Z_DR column. These parameters indicate rapid development of mixed-phase conditions initiated by freezing of supercooled raindrops. Lightning was observed only in the central and strongest convective cell. Electric fields exceeding 10 k V m^-1 were noted during aircraft penetrations in this as well as several other cells that did not produce lightning. Fields exceeding 1 k V m^-1 were noted by the instrumented aircraft at midcloud levels within a few minutes of development of mixed-phase conditions at these levels or aloft. The first intracloud lightning was detected by the surface field mill network within 5 min of development of mixed-phase conditions aloft in the first cycle of development in the central cell, and the first cloud-to-ground event was noted within 9 min of this development. Lightning continued through two additional cycles of updraft growth in this central region and diminished as the convection subsided after about 30 min. Aircraft-measured electric fields and lightning retrievals from the surface field meter network are consistent with a tendency for negative charge to accumulate above the 6.5 km (-12°C) level within regions of radar reflectivity maxima and for positive charge to accumulate in the anvil region well above 9 km (-30°C).

Bushnell, M.H., and W.S. Krug. Global Drifter Center support for the International Buoy Program in the Indian Ocean. Final Report, Second WMO/DBCP International Indian Ocean Buoy Program Meeting, Perth, Australia, July 1997. Australian Bureau of Meteorology, Annex V, 15-20 (1997).

No abstract.

Cantillo, A.Y., and G.A. Berberian. MESA New York Bight Project water column chemistry data cruises No. 6-12 of the NOAA Ship Ferrel, April-November 1974. NOAA Technical Memorandum, ERL AOML-92 (PB98-140759), 74 pp. (1997).

During the period April-November 1974, seven oceanographic cruises, denoted WCC 6-12, were conducted by the NOAA Ship Ferrel to obtain samples of sea water and suspended particulates from the New York Bight Apex for chemical analyses. This report presents the chemical data obtained from these samples.

Carsey, T.P., D.D. Churchill, M.L. Farmer, C.J. Fischer, A.A.P. Pszenny, V.B. Ross, E.S. Saltzman, M. Springer-Young, and B. Bonsang. Nitrogen oxides and ozone production in the North Atlantic marine boundary layer. Journal of Geophysical Research, 102(D9):10,653-10,665 (1997).

Measurements of reactive nitrogen gases (NO, NO₂, NOy), as well as related chemical (O₃, CO, aerosol black carbon, radon, selected nonmethane hydrocarbons) and meteorological parameters, were made on board the R/V Malcolm Baldrige prior to and subsequent to the 1992 ASTEX (Atlantic Stratocumulus Transition Experiment) in the North Atlantic Ocean during June and July 1992. Results showed indications of well-defined plumes from North America and Europe from both chemistry and back trajectory data. Elevated ozone concentrations were also observed in air masses from uninhabited continental regions. Chemical and meteorological data were incorporated into a simple photochemical model in which ozone destruction predominated over generation. The principal reaction leading to ozone destruction was O(¹D) + H₂O - 2OH.

Checkley, D.M., P.B. Ortner, L.R. Settle, and S.R. Cummings. A continuous, underway fish egg sampler (CUFES). Fisheries Oceanography, 6(2):58-73 (1997).

We describe a method to sample the highly contagious distribution of pelagic fish eggs. CUFES, the continuous, underway fish egg sampler, consists of a submersible pump, concentrator, electronics, and sample collector. This system operates continuously and under nearly all sea conditions, providing a real-time estimate of the volumetric abundance of pelagic fish eggs at pump depth, usually 3 m. CUFES-derived estimates of volumetric abundance agree well with those from nets towed at pump depth and with a real abundance estimated from vertically-integrated plankton tows. CUFES has been used successfully to sample the eggs of menhaden, pinfish, sardine, and anchovy off the coasts of the eastern and western United States and South Africa. Two large patches of eggs of the Atlantic menhaden were sampled off North Carolina in winter 1993-1994, had a linear scale of 5-10 km, and were found in waters between the Gulf Stream and mid-shelf front. Spawning location may be related to bathymetry. CUFES is now being used to estimate spawner biomass by the Daily Egg Production Method. An optical plankton counter provided accurate estimates of the number of Atlantic menhaden eggs sampled by CUFES. Automation of egg counting in CUFES is under development.

Chelton, D.B., and A.M. Mestas-Nunez. The large-scale, wind-driven response of the North Pacific. International WOCE Newsletter, 25:3-6 (1997).

In this note, we present the results of an investigation of the validity of the time-varying Sverdrup balance in the North Pacific based on analysis of three years of: (1) a simple flat bottom Sverdrup model; (2) the primitive equation global ocean circulation model developed by the Parallel Ocean Program (POP) at the Los Alamos National Laboratory; and (3) observations of sea surface height (SSH) by the TOPEX/POSEIDON (T/P) altimeter. The three-year period considered here is October 1992 through November 1995. We conclude that much of the large-scale, low-frequency variability in the North Pacific can be accounted for by simple Sverdrup dynamics.

Chen, G., B. Chapron, J. Tournadre, K.B. Katsaros, and D. Vandemark. Global oceanic precipitation: A joint view by TOPEX and the TOPEX microwave radiometer. Journal of Geophysical Research, 102(C5):10,457-10,471 (1997).

The TOPEX/POSEIDEN mission offers the first opportunity to observe rain cells over the ocean by a dual-frequency radar altimeter (TOPEX) and simultaneously observe their natural radiative properties by a three-frequency radiometer (TOPEX microwave radiometer (TMR)). This work is a feasibility study aimed at understanding the capability and potential of the active/passive TOPEX/TMR system for oceanic rainfall detection. On the basis of past experiences in rain flagging, a joint TOPEX/TMR rain probability index is proposed. This index integrates several advantages of the two sensors and provides a more reliable rain estimate than the radiometer alone. One year's TOPEX/TMR data are used to test the performance of the index. The resulting rain frequency statistics show quantitative agreement with those obtained from the Comprehensive Ocean-Atmosphere Data Set (COADS) in the Intertropical Convergence Zone (ITCZ), while qualitative agreement is found for other regions of the world ocean. A recent finding that the latitudinal frequency of precipitation over the Southern Ocean increases steadily towards the Antarctic continent is confirmed by our result. Annual and seasonal precipitation maps are derived from the index. Notable features revealed include an overall similarity in rainfall pattern from the Pacific, the Atlantic, and the Indian Oceans and a general phase reversal between the two hemispheres, as well as a number of regional anomalies in terms of rain intensity. Comparisons with simultaneous Global Precipitation Climatology Project (GPCP) multisatellite precipitation rates and COADS rain climatology suggest that systematic differences also exist. One example is that the maximum rainfall in the ITCZ of the Indian Ocean appears to be more intensive and concentrated in our result compared to that of the GPCP. Another example is that the annual precipitation produced by TOPEX/TMR is constantly higher than those from GPCP and COADS in the extratropical regions of the northern hemisphere, especially in the northwest Pacific Ocean. Analyses of the seasonal variations of prominent rainy and dry zones in the tropics and subtropics show various behaviors such as systematic migration, expansion, and contraction, merging and breakup, and pure intensity variations. The seasonality of regional features is largely influenced by local atmospheric events such as monsoon, storm, or snow activities. The results of this study suggest that TOPEX and its follow-on may serve as a complementary sensor to the special sensor microwave/imager in observing global oceanic precipitation.

Chereskin, T.K., W.D. Wilson, H.L. Bryden, A. Ffield, and J. Morrison. Observations of the Ekman balance at 8°30'N in the Arabian Sea during the 1995 southwest monsoon. Geophysical Research Letters, 24(21):2541-2544 (1997).

The Ekman transport is estimated from two sets of hydrographic and shipboard acoustic Doppler current profiler (ADCP) velocity observations made during June and September 1995, during the southwest monsoon in the Arabian Sea. Both sets of measurements were made along latitude 8°30'N, designated as World Ocean Circulation Experiment (WOCE) line I1W, from Somalia to Sri Lanka. The Ekman transport estimates calculated from ageostrophic velocity were southward: 17.6 ± 2.4 10⁶ m³ s^-1 in June and 7.9 ± 2.7 10⁶ m³ s^-1 in September. These direct estimates were in good agreement with those predicted by the Ekman balance using both shipboard and climatological winds. The vertical structure of the ageostrophic velocity and the stratification were quite different between the two occupations of the transect. The wind-driven momentum was confined to a very shallow layer in June (about 50 m) and the surface layer was strongly stratified, with a maximum salinity layer at depths between 50 and 70 m. The ageostrophic velocity penetrated much deeper in September (to about 160 m) and the pycnocline was correspondingly deeper. In both cases, the Ekman transport penetrated beneath the mixed layer, to the top of the pycnocline.

Cione, J.J., and S. Raman. The impact of SST gradients on propagating low-level mesovortices near the Gulf Stream. Preprints, Conference on Coastal Oceanic and Atmospheric Prediction, Atlanta, GA, January 28- February 2, 1996. American Meteorological Society, Boston, 204-211 (1997).

No abstract.

DeMaria, M., and J. Kaplan. An operational evaluation of a statistical intensity prediction scheme (SHIPS). Preprints, 22nd Conference on Hurricanes and Tropical Meteorology, Ft. Collins, CO, May 19-23, 1997. American Meteorological Society, Boston, 280-281 (1997).

No abstract.

Dietrich, D.E., C.A. Lin, A.M. Mestas-Nunez, and D.-S. Ko. A high resolution numerical study of Gulf of Mexico fronts and eddies. Meteorology and Atmospheric Physics, 64(3-4):187-201 (1997).

The Gulf of Mexico (GOM) circulation is simulated using the DieCAST ocean model, with a horizontal resolution of 1/12 degree and 20 vertical layers. The results compare well with observations of both large and small scale features, including Loop Current frontal occlusions associated with frontal eddies. The simulation is carried out without any data assimilation. The frontal eddies tend to be spaced at about 90 degree intervals around the Loop Current, leading to a Loop Current head shaped like a square with rounded corners. The pattern rotates as eddies circle the Loop, and frontal eddies elongate as they squeeze through the Florida Strait. Major warm core eddies separate regularly from the Loop Current and propagate to the western GOM. Old warm core eddies in the western Gulf dissipate through bottom drag effects, which also generate cyclonic parasitic eddies. Newly arrived warm core eddies merge with old ones in the western GOM. Recently separated elongated Loop Current eddies can rotate and reattach temporarily to the Loop Current. The barotropic flow component develops eddies between the main separated warm core eddy and the Loop Current due to eastward dispersion, as the main eddy itself propagates westward into the Gulf.

Dodge, P.P., S.H. Houston, and J.F. Gamache. Three-dimensional windfields in Hurricane Fran (1996) at landfall. Preprints, 22nd Conference on Hurricanes and Tropical Meteorology, Ft. Collins, CO, May 19-23, 1997. American Meteorological Society, Boston, 115-116 (1997).

No abstract.

Dodge, P.P., S.H. Houston, and J.F. Gamache. Windfields in Hurricane Fran (1996) at landfall from combined WSR-88D and airborne Doppler radar data. Proceedings, 28th Conference on Radar Meteorology, Austin, TX, September 9-12, 1997. American Meteorological Society, Boston, 575-576 (1997).

No abstract.

Donelan, M.A., W.M. Drennan, and K.B. Katsaros. The air-sea momentum flux conditions of wind sea and swell. Journal of Physical Oceanography, 27(10):2087-2099 (1997).

During the Surface Wave Dynamics Experiment, direct measurements of momentum, heat, and water vapor fluxes were obtained from a mast on the foredeck of a SWATH (small water-plane area, twin hull) ship in deep water off the state of Virginia. Directional wave spectra were obtained simultaneously from a six or three-wire wave-staff array mounted at the bow of the ship. One hundred and twenty-six 17-minute runs of flux and wave data obtained with the ship steaming slowly into the wind are examined for the effects of the relative direction of the wind sea and background swell on the momentum transfer. The adequacy of the inertial dissipation method, which depends on the high-frequency turbulent fluctuations for evaluating the wind stress, is also examined for any effects of swell. The results show that the presence of counter- and cross-swells can result in drag coefficients that are much larger than the value for a pure wind sea. The eddy correlation and inertial dissipation methods for measuring wind stress are found to diverge during the complex sea conditions. The authors interpret the latter observations as an indication that the traditional inertial dissipation method, in which the pressure and transport terms in the kinetic energy balance equation are assumed to be in balance, may be unsuitable for use in a marine boundary layer disturbed by swell.

Drennan, W.M., M.A. Donelan, E.A. Terray, and K.B. Katsaros. On waves, oceanic turbulence, and their interaction. Geophysica, 33:17-28 (1997).

No abstract.

Dupuis, H., P.K. Taylor, A. Weill, and K.B. Katsaros. Inertial dissipation method applied to derive turbulent fluxes over the ocean during the Surface of the Fluxes and Interactions with the Atmosphere/Atlantic Stratocumulus Transition Experiment (SOFIA/ASTEX) and Structure des Echanges Mer-Atmosphere, Proprietes des Heterogeneites Oceaniques: Recherche Experimentale (SEMAPHORE) experiments with low to moderate wind speeds. Journal of Geophysical Research, 102(C9):21,115-21,129 (1997).

The transfer coefficients for momentum and heat have been determined for 10 m neutral wind speeds (U_10n) between 0 and 12 m/s using data from the Surface of the Ocean, Fluxes and Interactions with the Atmosphere (SOFIA) and Structure des Echanges Mer-Atmosphere, Proprietes des Heterogeneites Oceaniques: Recherche Experimentale (SEMAPHORE) experiments. The inertial dissipation method was applied to wind and pseudo virtual temperature spectra from a sonic anemometer, mounted on a platform (ship) which was moving through the turbulence field. Under unstable conditions the assumptions concerning the turbulent kinetic energy (TKE) budget appeared incorrect. Using a bulk estimate for the stability parameter, Z/L (where Z is the height and L is the Obukhov length), this resulted in anomalously low drag coefficients compared to neutral conditions. Determining Z/L iteratively, a low rate of convergence was achieved. It was concluded that the divergence of the turbulent transport of TKE was not negligible under unstable conditions. By minimizing the dependence of the calculated neutral drag coefficient on stability, this term was estimated at about -0.65 Z/L. The resulting turbulent fluxes were then in close agreement with other studies at moderate wind speed. The drag and exchange coefficients for low wind speeds were found to be C_en × 10³ = 2.79 U_10n^-1 + 0.66 (U_10n < 5.2 m/s), C_en × 10³ = C_hn × 10³ = 1.2 (U_10n > 5.2 m/s), and C_dn × 10³ = 11.7 U_10n^-2 + 0.668 (U_10n < 5.5 m/s), which imply a rapid increase of the coefficient values as the wind decreased within the smooth flow regime. The frozen turbulence hypothesis and the assumptions of isotropy and an inertial subrange were found to remain valid at these low wind speeds for these shipboard measurements. Incorporation of a free convection parameterization had little effect.

Elfouhaily, T., B. Chapron, K.B. Katsaros, and D. Vandemark. A unified directional spectrum for long and short wind-driven waves. Journal of Geophysical Research, 102(C7):15,781-15,796 (1997).

Review of several recent ocean surface wave models finds that while comprehensive in many regards, these spectral models do not satisfy certain additional, but fundamental, criteria. We propose that these criteria include the ability to properly describe diverse fetch conditions and to provide agreement with in-situ observations of Cox and Munk (1954), Jahne and Riemer (1990), and Hara et al. (1994) data in the high-wavenumber regime. Moreover, we find numerous analytically undesirable aspects such as discontinuities across wavenumber limits, nonphysical tuning or adjustment parameters, and noncentrosymmetric directional spreading functions. This paper describes a two-dimensional wavenumber spectrum valid over all wavenumbers and analytically amenable to usage in electromagnetic models. The two regime model is formulated based on the Joint North Sea Wave Project (JONSWAP) in the long-wave regime and on the work of Phillips (1985) and Kitaigorodskii (1973) at the high wavenumbers. The omnidirectional and wind-dependent spectrum is constructed to agree with past and recent observations including the criteria mentioned above. The key feature of this model is the similarity of description for the high- and low-wavenumber regimes; both forms are posed to stress that the air-sea interaction process of friction between wind and waves (i.e., generalized wave age, u/c) is occurring at all wavelengths simultaneously. This wave age parameterization is the unifying feature of the spectrum. The spectrum's directional spreading function is symmetric about the wind direction and has both wavenumber and wind speed dependence. A ratio method is described that enables comparison of this spreading function with previous noncentrosymmetric forms. Radar data are purposefully excluded from this spectral development. Finally, a test of the spectrum is made by deriving roughness length using the boundary layer model of Kitaigorodskii. Our inference of drag coefficient versus wind speed and wave age shows encouraging agreement with Humidity Exchange Over the Sea (HEXOS) campaign results.

Enfield, D.B., and D.A. Mayer. Tropical Atlantic sea surface temperature variability and its relation to El Niño-Southern Oscillation. Journal of Geophysical Research, 102(C1):929-945 (1997).

Past analyses of tropical Atlantic sea surface temperature variability have suggested a dipole behavior between the northern and southern tropics, across the Intertropical Convergence Zone (ITCZ). By analyzing an improved 43-year (1950-1992) record of SST (Smith et al., 1996) and other data derived from the Comprehensive Ocean-Atmosphere Data Set (COADS), it is shown that the regions north and south of the ITCZ are statistically independent of each other at the seasonal to interannual time scales dominating the data, confirming the conclusions of Houghton and Tourre (1992). Some dipole behavior does develop weakly during the boreal spring season, when there is a tendency for SST anomaly west of Angola to be opposite of that in the tropical North Atlantic. It is further shown that tropical Atlantic SST variability is correlated with Pacific El Niño-Southern Oscillation (ENSO) variability in several regions. The major region affected is the North Atlantic area of northeast trades west of 40°W along 10°N-20°N and extending into the Caribbean. There, about 50-80% of the anomalous SST variability is associated with the Pacific ENSO, with Atlantic warmings occurring 4-5 months after the mature phases of Pacific warm events. An analysis of local surface flux fields derived from COADS data show that the ENSO-related Atlantic warmings occur as a result of reductions in the surface northeast trade wind speeds, which in turn reduce latent and sensible heat losses over the region in question, as well as cooling due to entrainment. This ENSO connection is best developed during the boreal spring following the most frequent season of maximum ENSO anomalies in the Pacific. A region of secondary covariability with ENSO occurs along the northern edge of the mean ITCZ position and appears to be associated with northward migrations of the ITCZ when the North Atlantic warmings occur. Although easterly winds are intensified in the western equatorial Atlantic in response to Pacific warm events, they do not produce strong local changes in SST. Contrary to expectations from studies based on equatorial dynamics, these teleconnected wind anomalies do not give rise to significant correlations of SST in the Gulf of Guinea with the Pacific ENSO. As the teleconnection sequence matures, strong southeast trades at low southern latitudes follow the development of the North Atlantic SST anomaly and precede by several months the appearance of weak negative SST anomalies off Angola and stronger positive anomalies extending eastward from southern Brazil along 15°-30°S.

Faber, T., L.K. Shay, S.D. Jacob, S.H. Houston, and P.G. Black. Observed air-sea interactions during Hurricane Emily. Preprints, 22nd Conference on Hurricanes and Tropical Meteorology, Ft. Collins, CO, May 19-23, 1997. American Meteorological Society, Boston, 433-434 (1997).

No abstract.

Feely, R.A., R.H. Wanninkhof, C. Goyet, D.E. Archer, and T. Takahashi. Variability of CO₂ distributions and sea- air fluxes in the central and eastern equatorial Pacific during the 1991-1994 El Niño. Deep-Sea Research, Part II, 44(9-10):1851-1867 (1997).

As part of the U.S. JGOFS Program and the NOAA Ocean-Atmosphere Carbon Exchange Study (OACES), measurements of CO₂ partial pressure were made in the atmosphere and in the surface waters of the central and eastern equatorial Pacific during the boreal spring and autumn of 1992, the spring of 1993, and the spring and autumn of 1994. Surface-water pCO₂ data indicate significant diurnal, seasonal, and interannual variations. The largest variations were associated with the 1991-1994 ENSO event, which reached maximum intensity in the spring of 1992. The lower values of surface-water DELTApCO₂ observed during the 1991-1994 ENSO period were the result of the combined effects of both remotely and locally forced physical processes. The warm pool, which reached a maximum eastward extent in January-February of 1992, began in September of 1991 as a series of westerly wind events lasting about 30 days. Each wind event initiated an eastward-propagating Kelvin wave which caused a deepening of the thermocline. By the end of January 1992 the thermocline was at its maximum depth, so that the upwelled water was warm and CO₂-depleted. In April of the same year, the local winds were weaker than normal, and the upwelling was from shallow depths. These changes resulted in a lower-than-normal CO₂ flux to the atmosphere. The results show that for the one-year period from the fall of 1991 until the fall of 1992, approximately 0.3 GtC were released to the atmosphere; 0.6 GtC were released in 1993, and 0.7 GtC in 1994, in good agreement with the model results of Ciais et al. (Science, 269, 1098-1102; J. Geophys. Res., 100, 5051-5070). The net reduction of the ocean-atmosphere CO₂ flux during the 1991-1994 El Ni�o was on the order of 0.8-1.2 GtC. Thus, the total amount of CO₂ sequestered in the equatorial oceans during the prolonged 1991-1994 El Ni�o period was about 25% higher than the severe El Ni�o of 1982-1983.

Festa, J.F., and R.L. Molinari. Comparison of thermal statistics derived from observational data sets in the tropical Atlantic and Pacific Oceans. NOAA Technical Memorandum, ERL AOML-91 (PB97-208177), 88 pp. (1997).

Statistical analysis of surface and subsurface temperature data in the tropical Atlantic and Pacific Oceans is presented. The statistics were estimated from the Comprehensive Ocean-Atmospheric Data Set (COADS) and the historical expendable bathythermograph (XBT) observations. Spatial structure functions (semivariograms) for the anomaly fields of sea surface temperature and the temperature at 200 m and 400 m were estimated for a 2 degree by 2 degree grid in the tropical oceans. Dominant scales of spatial variability are identified and compared with other investigations.

Ffield, A., J. Toole, and W.D. Wilson. Seasonal circulation in the South Indian Ocean. Geophysical Research Letters, 24(22):2773-2776 (1997).

Two World Ocean Circulation Experiment hydrographic cruises in March and June 1995, along with Topex-Poseidon altimeter data and National Meteorological Center wind data, are used to estimate seasonal changes in the South Indian Ocean subtropical gyre. Mean annual curves derived from the altimeter and wind data reveal strengthening of the anticyclonic gyre in March and September, and weakening in June and December. The seasonal changes correspond to variations in the wind field south of 30 S at the equinoxes and solstices. In addition, the wind-driven gyre is further north in July, and further south in March. These variations in strength and location of the South Indian Ocean gyre may influence inter-ocean transports south of Africa. Despite the inferred mean annual seasonal variations in the South Indian Ocean gyre, volume transports estimated in 1995 from the hydrographic data are close to mean values. Apparently, a mesoscale eddy in March disrupts the stronger fall gyre, whereas in June the weaker winter gyre is delayed by 1 month.

Franklin, J.L., H.L. Cole, T.F. Hock, D.K. Lauritsen, K.D. Norris, and E.F. Chamberlain. GPS dropwindsondes and the NOAA G-IV jet aircraft: New opportunities for forecasting and research. Preprints, 22nd Conference on Hurricanes and Tropical Meteorology, Ft. Collins, CO, May 19-23, 1997. American Meteorological Society, Boston, 135-136 (1997).

No abstract.

Gallagher, M.S., D.B. King, P.-Y. Whung, and E.S. Saltzman. Performance of the HPLC/fluorescence SO₂ detector during the GASIE instrument intercomparison experiment. Journal of Geophysical Research, 102(D13):16,247-16,254 (1997).

Sulfur dioxide (SO₂) in synthetic air and diluted ambient air was measured as part of the Gas-Phase Sulfur Intercomparison Experiment (GASIE) using the high performance liquid chromatography (HPLC)/fluorescence technique. SO₂ was analyzed by equilibrating the gaseous sample with aqueous SO₂, sulfite, and bisulfite, then converting the aqueous S(IV) to an isoindole derivative. The derivative was separated by reversed phase HPLC and detected via fluorescence. The system was calibrated with mixtures of SO₂ in zero air prepared from an SO₂ permeation device through a two-stage dilution system. The instrument has a 4-minute sample integration time and a measurement period of 9 minutes. During the GASIE intercomparison, the lower limit of detection averaged 3.6 parts per trillion by volume (pptv). The precision of replicate measurements over the entire intercomparison period was better than 5% at the 20 pptv level. Instrument performance was unaffected by the interferent gases included in the GASIE protocol (H₂O, O₃, NO_x, DMS, CO, CO₂, and CH₄). During diluted ambient air tests, the HPLC/fluorescence technique exhibited an approximately 10% reduction in response relative to some other techniques. The cause of this apparent calibration change is not understood.

Gamache, J.F. Evaluation of a fully three-dimensional variational Doppler analysis technique. Proceedings, 28th Conference on Radar Meteorology, Austin, TX, September 9-12, 1997. American Meteorological Society, Boston, 422-423 (1997).

No abstract.

Gamache, J.F., H.E. Willoughby, M.L. Black, and C.E. Samsury. Wind shear, sea surface temperature, and convection in hurricanes observed by airborne Doppler radar. Preprints, 22nd Conference on Hurricanes and Tropical Meteorology, Ft. Collins, CO, May 19-23, 1997. American Meteorological Society, Boston, 121-122 (1997).

No abstract.

Garzoli, S.L., G.J. Goni, A.J. Mariano, and D.B. Olson. Monitoring the upper southeastern Atlantic transports using altimeter data. Journal of Marine Research, 55(3):453-481 (1997).

A large in-situ data set, collected in the southeastern Atlantic Ocean, is merged with the TOPEX/POSEIDON altimeter observations in order to verify the use of altimeter data in monitoring the transports of the Agulhas/Benguela system. Comparisons between altimeter observations and either moored current meters or inverted echo sounder measurements shows that the sea surface elevation anomaly is significantly correlated with the thermocline depth and the surface dynamic height, respectively. Knowing the least-squares regression parameters, it is possible to calculate the transports by using geostrophy and either a two-layer or a continuously-stratified model. The transports obtained from fits of dynamic height to altimeter sea surface height are similar to the ones calculated with the moored instruments. In the southern part of the area under analysis, around 35°S, close to the Agulhas retroflection, the transports obtained from the two-layer model are overestimated. Across the Benguela Current, at 30°S, transports are still overestimated but of the same order as the measured ones. In this part of the region, the two-layer model can be successfully used to calculate the total and barotropic transports of the Benguela Current. Analysis of the three years of geostrophic transport obtained from the altimeter data indicate that the mean Benguela Current transport does not change interannually more than 20%. However, the primary interannual variability derives from the source water that forms the Benguela Current.

German, C.R., D.L. Bourles, E.T. Brown, J. Hergt, S. Colley, N.C. Higgs, E.M. Ludford, T.A. Nelsen, R.A. Feely, G. Raisbeck, and F. Yiou. Hydrothermal scavenging on the Juan de Fuca Ridge: ²³⁰Th_xs, ¹⁰Be, and REEs in ridge-flank sediments. Geochimica et Cosmochimica Acta, 61(19):4067-4078 (1997).

We have investigated the geochemistry of a hydrothermally-enriched sediment core recovered from the western flank of the N.Cleft Segment, Juan de Fuca Ridge, 8 km west of the "MegaPlume" area previously identified near 45°N. The core contains varying biogenic, lithogenic, and hydrothermal components, as reflected in CaCO₃, Al, and Fe contents, respectively. Horizons of pronounced hydrothermal input, in core-top sediments and at depth, exhibit increased concentrations of Fe, Cu, Zn, Pb, and shifts in Pb isotopic compositions toward nonradiogenic (MORB/hydrothermal) values. REE concentrations co-vary with hydrothermal Fe down-core, and shale-normalized REE distributions patterns exhibit both negative Ce-anomalies and positive Eu-anomalies, indicative of input from plume-particle fall-out. Unsupported ²³⁰Th_xs activities down-core are consistent with continuous slow sediment accumulation rates of 0.54 cm/ky for 200 ky since the deposition of the deeper Fe-rich horizon. ¹⁰Be₍₀₎ and ⁹Be isotope concentrations also co-vary with hydrothermal Fe down-core and exhibit ¹⁰Be₍₀₎ ⁹Be ratios which approach that of Pacific Ocean deep water, indicative of a seawater-scavenging source. ¹⁰Be₍₀₎ ²³⁰Th_xs(0) ratios throughout most of Core GC88-6 are greater than mean Pacific Ocean values, indicating that hydrothermal scavenging can lead to significant net removal of dissolved ¹⁰Be into ridge-flank sediments.

Goldenberg, S.B., C.W. Landsea, and L.J. Shapiro. Are we seeing the beginning of a long-term upturn in Atlantic basin major hurricane activity? Proceedings, Tropical Cyclone Symposium, Melbourne, Australia, December 9-13 1996. U.S. Office of Naval Research, 10 pp. (1997).

No abstract.

Goldenberg, S.B., L.J. Shapiro, and C.W. Landsea. Are we seeing a long-term upturn in Atlantic basin major hurricane activity related to decadal-scale SST fluctuations? Preprints, 7th Conference on Climate Variations, Long Beach, CA, February 2-6, 1997. American Meteorological Society, Boston, 305-310 (1997).

No abstract.

Goldenberg, S.B., L.J. Shapiro, and C.W. Landsea. Mounting evidence for a decadal-scale upturn in Atlantic basin tropical cyclone activity. Preprints, 22nd Conference on Hurricanes and Tropical Meteorology, Ft. Collins, CO, May 19-23, 1997. American Meteorological Society, Boston, 507-508 (1997).

No abstract.

Goldenberg, S.B., L.J. Shapiro, and C.W. Landsea. The hyperactive 1995 Atlantic hurricane season: Just a spike or a harbinger of things to come? Proceedings, 21st Climate Diagnostics and Prediction Workshop, Hunstville, AL, October 28-November 1, 1996. American Meteorological Society, Boston, 9-12 (1997).

No abstract.

Goldenberg, S.B., L.J. Shapiro, and C.W. Landsea. The hyperactive 1995 Atlantic hurricane season: A spike or a harbinger of things to come? Workshop Proceedings, Climate Change and Climate Variability in the Atlantic, Halifax, Nova Scotia, December 3-6, 1996. American Meteorological Society, Boston, 113-119 (1997).

No abstract.

Goni, G.J., S.L. Garzoli, A.J. Roubicek, D.B. Olson, and O.B. Brown. Agulhas ring dynamics from TOPEX/POSEIDON satellite altimeter data. Journal of Marine Research, 55(5):861-883 (1997).

The transfer of warm water from the Indian Ocean into the South Atlantic subtropical gyre takes place in the form of rings and filaments formed when the Agulhas Current retroflects south of Africa between 15°E and 25°E. A survey of the rings formed from September 1992 until December 1995 in the retroflection region was carried out using TOPEX/POSEIDON altimeter data. A two-layer model was used to estimate the upper layer thickness from the altimeter-derived sea surface height anomaly data. An objective analysis scheme was used to construct a map of upper layer thickness every 10 days. Seventeen rings and their trajectories were identified using these maps. The shedding of rings from the Agulhas Current was neither continuous nor periodic, and for long periods there is no formation of rings. Several rings remained in the region for more than a year and, at any given time, two to six rings coexisted in the region east of the Walvis Ridge. The results showed that the number of rings translating simultaneously in this region is larger during the first half of each year. The upper layer transport of the Agulhas Current in the retroflection region was computed and a close association between high variations in transport and ring shedding was found. Rings translated west-northwest at translation speeds ranging from 5-16 km day^-1 following formation. The values of available potential energy computed for the rings place them among the most energetic rings observed in the world oceans, with values of up to 70 × 10¹⁵ J. Transport computations indicate that each ring contributes in the average approximately 1 Sv of Agulhas Current waters to the Benguela Current.

Gordon, A.L., S. Ma, D.B. Olson, P. Hacker, A. Ffield, L.D. Talley, W.D. Wilson, and M.O. Baringer. Advection and diffusion of Indonesian throughflow within the Indian Ocean South Equatorial Current. Geophysical Research Letters, 24(21):2573-2576 (1997).

Warm, low salinity Pacific water weaves through the Indonesian Seas into the eastern boundary of the Indian Ocean. The Indonesian Throughflow Water (ITW) adds freshwater into the Indian Ocean as it spreads by the advection and diffusion within the Indian Ocean's South Equatorial Current (SEC). The low salinity throughflow trace, centered along 12°S, stretches across the Indian Ocean, separating the monsoon dominated regime of the northern Indian Ocean from the more typical subtropical stratification to the south. ITW is well represented within the SEC thermocline, extending with concentrations above 80% of initial characteristics from the sea surface to 300-m within the eastern half of the Indian Ocean, with 60% concentration reaching well into the western Indian Ocean. The ITW transport within the SEC varies from 4 to 12 × 10⁶ m³ sec^-1, partly in response to variations of the injection rate at the eastern boundary and to the likelihood of a zonally elongated recirculation cell between the Equatorial Counter Current and the SEC within the Indian Ocean. Lateral mixing disperses the ITW plume meridionally with an effective isopycnal mixing coefficient of 1.1 to 1.6 × 10⁴ m² sec^-1.

Gray, W.M., J.D. Sheaffer, and C.W. Landsea. Climate trends associated with multi-decadal variability of Atlantic hurricane activity. In Hurricanes, Climate, and Socioeconomic Impacts, H.F. Diaz and R.S. Pulwarty (eds.). Springer, Berlin, 15-53 (1997).

No abstract.

Haddad, Z.S., D.A. Short, S.L. Durden, E. Im, S. Hensley, M.B. Grable, and R.A. Black. A new parameterization of the rain drop size distribution. IEEE, Transactions of Geoscience and Remote Sensing, 35(3):532-539 (1997).

This paper revisits the problem of finding a parametric form for rain drop size distribution (DSD) which (1) is an appropriate model for tropical rainfall, and (2) involves statistically-independent parameters. Using TOGA/COARE data, we derive a parameterization which meets these criteria. This new parameterization is an improvement on the one that was derived in [3], using TRMM ground truth data from Darwin, Australia. The new COARE data allows us to verify that the spatial variability of the two "shape" parameters is relatively small, thus confirming that this parameterization should be particularly useful for remote sensing applications. We also derive new DSD-based radar-reflectivity-rain-rate power laws, whose coefficients are directly related to the shape parameters of the DSD. Perhaps most important, since the coefficients are independent of the rain-rate itself, and very little spatially, the relations are ideally suited for rain retrieval algorithms. It should also prove straightforward to extend this method to the problems of extimating cloud hydrometeors from remote-sensing measurements.

Hasler, A.F., P.G. Black, V.M. Karyampudy, M. Jentoft-Nilsen, K. Palaniappan, and D. Chesters. Preprints, 22nd Conference on Hurricanes and Tropical Meteorology, Ft. Collins, CO, May 19-23, 1997. American Meteorological Society, Boston, 201-202 (1997).

No abstract

Hendee, J.C. Object-oriented analysis and design of a near real-time marine environmental data acquisition and reporting system. Proceedings, 8th International Coral Reef Symposium, Panama City, Panama, June 24-28, 1996. Smithsonian Tropical Research Institute, 2:1569-1574 (1997).

The National Oceanic and Atmospheric Administration's Coral Health and Monitoring Program has cooperated with the Florida Institute of Oceanography in developing a near real-time marine environmental monitoring and reporting system. Using an object-oriented analysis technique, this report describes how data are retrieved from satellite data and archiving facilities, then reformatted for presentation via a Remote Bulletin Board system and facsimile. Using an object-oriented design technique, a new system is designed using a requirements analysis of the original system.

Hitchcock, G.L., C. Wiebinga, and P.B. Ortner. CTD hydrographic data from the Global Ocean Ecosystem Dynamics (GLOBEC) Indian Ocean cruises. University of Miami Technical Report, RSMAS-97-006, 69 pp. (1997).

No abstract.

Hitchcock, G.L., W.J. Wiseman, W.C. Boicourt, A.J. Mariano, N. Walker, T.A. Nelsen, and E. Ryan. Property fields in an effluent plume of the Mississippi River. Journal of Marine Systems, 12(1-4):109-126 (1997).

Surface property distributions were mapped in the Mississippi River plume during May and August 1993 while following surface drifters. Prevailing winds were the primary factor controlling the orientation of the plume. In May, under typical southeasterly winds, the plume turned anticyclonically towards the coast, while in August, under anomalous westerly winds, the plume turned east. Remote imagery of sea surface temperature and suspended sediments confirmed the direction of the plume. Optimally interpolated maps of surface salinity, temperature, chlorophyll a fluorescence, and transmissivity from underway sampling, and periodic nutrient samples, reveal the plume structure. In May, concentrations of nitrate, silicate, and phosphate decreased linearly with increasing salinity. Chlorophyll a increased to peak concentrations of 10 µg 1^-1 in the plume, although higher pigment biomass was observed near the coast. In August, nitrate and silicate concentrations decreased conservatively near the mouth of Southwest Pass, except where pigment biomass was enhanced in a convergent surface front. Surface nutrient concentrations in the plume also decreased with increasing salinity. The observations provide the first Lagrangian view of surface property distributions in the Mississippi River plume, and indicate that significant temporal variability exists in physical and biological properties within a day after waters are discharged from the river delta.

Ho, D.T., L.F. Bliven, R.H. Wanninkhof, and P. Schlosser. The effect of rain on air-water gas exchange. Tellus B, 49(2):149-158 (1997).

The relationship between gas transfer velocity and rain rate was investigated at NASA's Rain- Sea Interaction Facility (RSIF) using several SF₆ evasion experiments. During each experiment, a water tank below the rain simulator was supersaturated with SF₆, a synthetic gas, and the gas transfer velocities were calculated from the measured decrease in SF₆ concentration with time. The results from experiments with 18 different rain rates (7 to 110 mm h^-1) and 1 of 2 dropsizes (2.8 or 4.2 mm diameter) confirm a significant and systematic enhancement of air-water gas exchange by rainfall. The gas transfer velocities derived from our experiment were related to the kinetic energy flux calculated from the rain rate and dropsize. The relationship obtained for mono-dropsize rain at the RSIF was extrapolated to natural rain using the kinetic energy flux of natural rain calculated from the Marshall-Palmer raindrop size distribution. Results of laboratory experiments at RSIF were compared to field observations made during a tropical rainstorm in Miami, Florida and show good agreement between laboratory and field data.

Ho, D.T., R.H. Wanninkhof, J.C. Masters, R.A. Feely, and C.E. Cosca. Measurement of underway fCO₂ in the eastern equatorial Pacific on NOAA Ships Malcolm Baldrige and Discoverer from February to September 1994. NOAA Data Report, ERL AOML-30 (PB97-169056), 66 pp. (1997).

From February through September 1994, underway measurements of the fugacity (partial pressure) of carbon dioxide (fCO₂) were performed in the eastern equatorial Pacific as part of the Ocean Atmosphere Carbon Exchange Study (OACES) of the National Oceanic and Atmospheric Administration (NOAA). The measurements were performed with semi-autonomous instruments which measured the fugacity in the air and in the headspace of an equilibrator drawing water from the bow of the ship, from which the fCO₂ of the surface water is calculated. From the difference in fugacity in air and water, the CO₂ flux from the equatorial Pacific can be estimated. On the NOAA Ship Malcolm Baldrige the system measured three reference standards, three air values, and eight water values per hour. The system on the Discoverer measured three standards, one 19-minute average air sample, and one 20-minute average water sample per hour. This report contains a description of the methodology and reduction of the fCO₂ and ancillary measurements. The results from the cruises of the Malcolm Baldrige in the equatorial Pacific in the (boreal) spring and fall of 1994 and from the Discoverer along nominally 110°W in the spring of 1994 are shown in a series of graphs with fCO₂ air and water versus latitude as top panel and temperature and salinity versus latitude as bottom panel.

Houston, S.H., M.D. Powell, and P.P. Dodge. Surface wind fields in 1996 Hurricanes Bertha and Fran at landfall. Preprints, 22nd Conference on Hurricanes and Tropical Meteorology, Ft. Collins, CO, May 19-23, 1997. American Meteorological Society, Boston, 92-93 (1997).

No abstract.

Johns, E., R.A. Fine, and R.L. Molinari. Deep flow along the western boundary south of the Blake Bahama Outer Ridge. Journal of Physical Oceanography, 27(10):2187-2208 (1997).

In June-July 1990, hydrographic, chloroflourocarbon (CFC), and direct velocity observations were taken in the western North Atlantic between the Blake Bahama Outer Ridge (BBOR) at 30°N and San Salvador Island at 24°N. The deep flow in the region, dominated by the Deep Western Boundary Current (DWBC), forms a pattern of strong, narrow currents and cyclonic gyres close to the continental slope, with broad, weaker southward flow offshore. The CFCs reveal that in general the most recently ventilated water (i.e., having the highest CFC concentrations) is found along the western boundary as two distinct cores within the DWBC between potential temperatures 4-6°C and 1.9-2.4°C. Geostrophic transport streamlines are constructed for the DWBC layers, referenced using direct velocity observations at 26.5°N and assuming mass conservation between closed areas bounded by the hydrographic sections. The tracers and transports are used to define the spatial scales and strengths of the recirculation gyres and to examine their relationship to bottom topography and their role in ventilating the interior. Geostrophic transports for the DWBC layers which transit the region and continue equatorward along the western boundary are approximately 5 Sv for the 4-6°C layer; 14 Sv for the 2.4-4.0°C layer; 9 Sv for the 1.9-2.4°C layer; and 3 Sv below 1.9°C, for a total equatorward DWBC transport of 31 Sv below 6°C. A cyclonic gyre with one or more embedded gyres extends out to about 74°W, transporting 12 Sv of water intermediate CFC concentrations. Farther offshore, a broad band of southward flow contributes an additional 16 Sv of water with lower CFC concentration to the total equatorward transport. This flow may be connected to a much larger elongated cyclonic recirculation gyre which reaches equatorward to the Guiana Basin off northeastern Brazil. The close correspondence of the tracer distributions with the regional topography indicates that the major topographic features in this region strongly influence the circulation, particularly in the deep and bottom layers. It appears that the most recently ventilated water, between 4-6°C and 1.9-2.4°C, does not reach the southern top of the BBOR, but rather it bypasses the BBOR to the north of the study region and turns back westward following the isobaths toward the western boundary north of 30°N. Only in the coldest layer (<1.9°C) are the relatively highest CFCs observed south of 30°N on the BBOR. The layer containing the shallow CFC core (4-6°C) is apparently less constrained by the bottom topography; 3 Sv are carried westward across the axis of the BBOR forming an extended zonal high CFC and salinity distribution related to the Gulf Stream recirculation. South of the BBOR, due to the steep topography west of the Blake Basin, the DWBC is channeled into a narrow equatorward boundary flow. At the San Salvador Spur, some of the more recently ventilated water appears to be deflected northward following the isobaths in a cyclonic gyre around the extension of the Bahama Ridge. The cyclonic gyres between the BBOR and the San Salvador Spur appear to be localized features close to the western boundary that may have little impact on the larger scale deep North Atlantic circulation. Nevertheless, the gyres serve to ventilate the interior by diluting the tracer concentration carried equatorward by the DWBC.

Jones, R.W., and H.E. Willoughby. Sensitivity of a spectral shallow-water barotropic vortex to variations of domain size and spectral truncation. Preprints, 22nd Conference on Hurricanes and Tropical Meteorology, Ft. Collins, CO, May 19-23, 1997. American Meteorological Society, Boston, 577-578 (1997).

No abstract.

Kaplan, J., C.W. Landsea, M. DeMaria, and J.J. Cione. The differing roles of the large-scale environment in the intensity changes of three 1996 Atlantic hurricanes. Preprints, 22nd Conference on Hurricanes and Tropical Meteorology, Ft. Collins, CO, May 19-23, 1997. American Meteorological Society, Boston, 358-359 (1997).

No abstract.

Knaff, J.A., and C.W. Landsea. An El Niño-Southern Oscillation Climatology and Persistence (CLIPER) forecasting scheme. Weather and Forecasting, 12(3):633-652 (1997).

A statistical prediction method is developed for the El Niño-Southern Oscillation (ENSO) phenomena which is based entirely on the optimal combination of persistence, month-to-month trend of initial conditions and climatology. The selection of predictors is by design intended to avoid any pretense of predictive ability based on "model physics" and the like, but rather is to specify the optimal "no-skill" forecast as a baseline comparison for more sophisticated forecast methods. Multiple least squares regression using the method of leaps and bounds is employed to test a total of fourteen possible predictors for the selection of the best predictors, based upon 1950-1994 developmental data. A range of zero to four predictors were chosen in developing twelve separate regression models, developed separately for each initial calendar month. The predictands to be forecast include the Southern Oscillation (pressure) Index (SOI) and the Niño 1+2, Niño 3, Niño 4 and Niño 3.4 SST indices for the equatorial eastern and central Pacific at lead times ranging from zero seasons (0-2 months) through seven seasons (18-20 months). Though hindcast ability is strongly seasonally dependent, substantial improvement is achieved over simple persistence wherein largest gains occur for two to seven season (6 to 21 months) lead times. For example, expected maximum forecast ability for the Niño 3.4 SST region, depending on the initial date, reaches 92, 85, 64, 41, 36, 24, 24 and 28 percent of variance for leads of zero to seven seasons. Comparable maxima of persistence only forecasts explain 92, 77, 50, 17, 6, 14, 21 and 17 percent, respectively. More sophisticated statistical and dynamical forecasting models are encouraged to utilize this ENSO-CLIPER model in place of persistence when assessing whether they have achieved forecasting skill; to this end, real-time results for this model are made available via a Web site.

Lamb, M.F., J.L. Bullister, R.A. Feely, G.C. Johnson, D.P. Wisegarver, B. Taft, R.H. Wanninkhof, K.E. McTaggart, K.A. Krogslund, C.W. Mordy, K. Hargreaves, D. Greeley, T. Lantry, H. Chen, B.E. Huss, F.J. Millero, R.H. Byrne, D.A. Hansell, F.P. Chavez, P.D. Quay, P.R. Guenther, J.-Z. Zhang, W. Gardner, M.J. Richardson, and T.-H. Peng. Chemical and hydrograph measurements in the eastern Pacific during the CGC94 expedition (WOCE section P18). NOAA Data Report, ERL PMEL-61 (PB97-158075), 235 pp. (1997).

NOAA's Climate and Global Change (CGC) Program sponsored a major cooperative effort in the eastern Pacific along WOCE Hydrographic Programme Line P18 from 26 January to 27 April 1994. The first leg (Leg 1) consisted of a transit from Seattle to Punta Arenas, Chile. The second leg (Leg 2) covered hydrographic stations from 67�S, 103�W to 27�S, 103�. The third leg (Leg 3) included stations between 26.5�S, 103�W and 23�N, 110�W. Full depth CTD/rosette casts were made to the ocean bottom at a nominal spacing of 30 miles on Legs 2 and 3. Water samples were collected on the casts for analyses of concentrations of salinity, DO, CFC, fCO₂, DIC, TAlk, pH, TOC/TON, ¹³C/¹²C isotopes, and nutrients. Biological parameters were also sampled, and included biogenic Si, chlorophyll-a, phaeopigments, and primary productivity.

Landsea, C.W. Comments on "Will greenhouse gas-induced warming over the next 50 years lead to higher frequency and greater intensity of hurricanes?" Tellus A, 49(5):622-623 (1997).

No abstract.

Landsea, C.W., G.D. Bell, W.M. Gray, and S.B. Goldenberg. The hyperactive 1995 Atlantic hurricane season: A juxtaposition of favorable conditions. Preprints, 22nd Conference on Hurricanes and Tropical Meteorology, Ft. Collins, CO, May 19-23, 1997. American Meteorological Society, Boston, 505-506 (1997).

No abstract.

Landsea, C.W., N. Nicholls, W.M. Gray, and L.A. Avilia. Reply to comment by R.W. Wilson on "Downward trend in the frequency of intense Atlantic hurricanes during the past five decades. Geophysical Research Letters, 24(17):2205-2206 (1997).

No abstract.

Lee, K., F.J. Millero, and R.H. Wanninkhof. The carbon dioxide system in the Atlantic Ocean. Journal of Geophysical Research, 102(C7):15,693-15,708 (1997).

During the National Oceanic and Atmospheric Administration's Ocean Atmosphere Carbon Exchange Study expedition in the eastern North Atlantic in summer 1993, measurements of four CO₂ parameters, along with hydrographic properties, were made: fugacity of CO₂, fCO₂ (measured at 20°C and in situ); pH (measured at 20°C); total inorganic carbon, TCO₂; and total alkalinity, TA. The major objective of this cruise was to establish a benchmark against which future measurements of the transient invasion of CO₂ can be made. The large-scale distributions of surface water CO₂ parameters were related to temperature and salinity in this region. The subsurface TA and TCO₂ measurements were fitted to multiple linear functions of salinity, in situ temperature, apparent oxygen utilization, and silicate. The measurements of the inorganic carbon system were also used to examine the internal consistency of the carbonate system in this area. The measurements were internally consistent to ±1.3% in fCO₂, ±0.006 in pH, ±3 µmol kg^{- 1} in TCO₂, and ±3 µmol kg^-1 in TA if proper carbonic acid dissociation constants are used for different input combinations. The thermodynamic constants of Goyet and Poisson (1989), Roy et al. (1993), Millero (1995), and Lee and Millero (1995) were most consistent with the measurements of pH (at 20°C), TCO₂, and TA. However, if fCO₂ (at 20°C) is used in thermodynamic calculations, the constants of Mehrbach et al. (1973) gave the best representation of measurements. The constants of Lee and Millero (1995) were also in reasonable agreement with these measurements.

Lobert, J.M., S.A. Yvon-Lewis, J.H. Butler, S.A. Montzka, and R.C. Myers. Undersaturations of CH₃Br in the Southern Ocean. Geophysical Research Letters, 24(2):171-172 (1997).

Dry mole fractions of methyl bromide (CH₃Br) in marine boundary layer air and air equilibrated with surface seawater were measured in the Southern Ocean. Saturation anomalies were consistently negative at -36 ± 7%. The observed undersaturations do not support recently published predictions of highly supersaturated Antarctic waters, but instead suggest a net uptake of atmospheric CH₃Br by cold, productive oceans. The observations do not appear to be supported by known chemical degradation rates and present strong evidence for an unidentified, oceanic sink mechanism such as biological breakdown. Our estimate for the global, net, oceanic sink for atmospheric methyl bromide remains negative at -21 (-11 to -32) Gg y^-1.

Marks, F.D., and P.P. Dodge. Hurricane concentric eyewall characteristics as revealed by airborne Doppler radar analyses. Preprints, 22nd Conference on Hurricanes and Tropical Meteorology, Ft. Collins, CO, May 19-23, 1997. American Meteorological Society, Boston, 102-103 (1997).

No abstract.

Martin, D., M. Tsivou, B. Bonsang, C. Abonnel, T.P. Carsey, M. Springer-Young, and A.A.P. Pszenny. Hydrogen peroxide (H₂O₂) in the marine atmospheric boundary layer during the ASTEX/MAGE experiment in the eastern subtropical North Atlantic. Journal of Geophysical Research, 102(D5):6003-6015 (1997).

Gas phase hydrogen peroxide (H₂O₂) was measured in surface air on the NOAA ship Malcolm Baldrige from June 8-27, 1992 (Julian days 160-179), during the Atlantic Stratocumulus Transition Experiment/Marine Aerosol and Gas Exchange experiment in the eastern subtropical North Atlantic region. Average H₂O₂ mixing ratios observed were 0.63 � 0.28 ppbv, ranging between detection limit and 1.5 ppbv. For the entire experiment, only weak or no correlation was found between H₂O₂ mixing ratio and meteorological parameters (pressure, temperature, humidity, or UV radiation flux), as well as with tracers of continental air masses (CO, black carbon, radon). The average daily H₂O₂ cycle for the entire period exhibits a maximum of 0.8 � 0.3 ppbv near sunset and a minimum of 0.4 � 0.2 ppbv 4-5 hours after sunrise. Several clear H₂O₂ diurnal variations have been observed, from which a first-order removal rate of about 1 x 10^-5 s^-1 for H₂O₂ can be inferred from nighttime measurements. This rate compares well with those deduced from measurements taken at Cape Grim (Tasmania, 41°S) and during the Soviet-American Gas and Aerosol III experiment (equatorial Pacific Ocean).

Masters, J.C., R.H. Wanninkhof, D.T. Ho, M. Steckley, R.A. Feely, and C. Cosca. Continuous air and surface seawater measurements of fCO₂ on board the NOAA ship Malcolm Baldrige around-the-world cruise in 1995. NOAA Data Report, ERL AOML-31 (PB98-105950), 80 pp. (1997).

From February 1995 through January 1996 the NOAA ship Malcolm Baldrige conducted scientific operations on an around-the-world tour. The majority of work occurred in the Indian Ocean. The CO₂ groups of the National Oceanic and Atmospheric Administration's (NOAA) Atlantic Oceanographic and Meteorological Laboratory (AOML) and Pacific Marine Environmental Laboratory (PMEL) operated a continuously flowing partial pressure carbon dioxide analyzer. Samples were taken from both the surface water and the overlying atmosphere to determine carbon dioxide flux across the gas/water interface. Other parameters such as salinity, barometric pressure, and temperature were used to reduce the data and calculate the fugacity of CO₂*. Total dissolved inorganic carbon (DIC) samples of surface water were also collected. Data were collected on each leg of the cruise. Leg 1 was a transit from Miami to Durban, South Africa. Leg 2 operated from Durban to Colombo, Sri Lanka. Leg 3 operated from Colombo to Muscat, Oman. Leg 4 operated from Muscat to Victoria, Seychelles. Leg 5 operated from Victoria to Muscat, Oman. Leg 6 operated from Muscat to Diego Garcia. Leg 7 consisted of a transit from Diego Garcia to Fremantle, Australia followed by the major scientific operations between Fremantle and Male, Maldive Islands. Leg 8 included another transit from Male to Darwin, Australia. Operations began after leaving Darwin and headed into the western equatorial Pacific. The ship inported in American Samoa and continued to Panama, Miami, Florida and finished in Charleston, South Carolina. Descriptions of sampling methods and graphical data summaries are given in this report.

Maul, G.A., M.H. Bushnell, N.J. Bravo, and D.V. Hansen. Observed sea surface height and modeled dynamic height anomaly departures in the tropical Pacific Ocean: 1986-1989. Oceanologica Acta, 20(4):569-584 (1997).

Observations of sea surface height variations (SSH') from November 1986 through September 1989 in the tropical Pacific from the improved (T2) GEOSAT data set (Cheney et al., 1991) are compared with monthly mean dynamic height anomaly departure (DELTA-D') from the "second reanalysis" using the NOAA ocean analysis system (Ji et al., 1994, 1995). For comparisons, DELTA-D' is calculated by removing north-south tilt and bias as in SSH orbit error removal, giving standard deviation fields sigma_SSH' and sigma_DELTA-D' that quantitatively reproduce variability of the North Equatorial Current (NEC)/North Equatorial Countercurrent (NECC)/South Equatorial Current (SEC) system between El Ni�o and non-El Ni�o years. Hovmoller diagrams of SSH' and DELTA-D' variability at 110°W, 140°W, 170°W, and 165°E between 20°S and 20°N, and along the equator from 120°E to 80°W, display the amplitude and phase of the 1986-1987 El Ni�o-Southern Oscillation (ENSO) event as distinguished from the years following, with the NECC significantly weakened in 1987 as compared to 1988. Cross correlations (r) between DELTA-D' and SSH' are highest near the equator in the vicinity of the TOGA-TAO (Hayes et al., 1991; McPhaden, 1993) in situ mooring arrays, with values above r = 0.7 in much of the region �7° of the equator across about half of the Pacific basin. Differences between DELTA-D' and SSH' are typically less than �5 cm RMS in this same equatorial band, but there are two regions of differences in excess of �15 cm RMS: off Central America and east of New Guinea. The reason for these large RMS differences is uncertain, but it is advanced from Lagrangian buoy data that intense eddy activity is unresolved in the model as compared to GEOSAT. For the 35 monthly realizations, the ensemble cross-correlation r = 0.5 has �7 cm RMS within �15° of the equator, and peaks in 1988 with decay towards the end of the GEOSAT Exact Repeat Mission (ERM) in September 1989. Seasonally, both SSH' and DELTA-D' show that the boreal winter (DJF) of 1987 is dominated by the ENSO-related sea level maximum in mid-basin, which is absent in the following two winters; spring (MAM) and summer (JJA) of all three years have little resemblance to each other, with 1987 and 1989 being more similar than 1988; autumn (SON) of 1988 shows a well developed NECC across of the eastern Pacific centered at 7°N. The ERM altimeter data and the model calculations of the annual cycle both show east-west height amplitude maxima along 5°N and 10°N that explain more than 50% of the variance for a substantial portion of the central Pacific Ocean. Concurrent drogued buoy tracks show more eddies along ~5°N in the eastern Pacific in 1988 as compared to 1987 or 1989, but DELTA-D' is unable to resolve these features.

McCarthy, M.C., L.D. Talley, and M.O. Baringer. Deep upwelling and diffusivity in the southern Central Indian Basin. Geophysical Research Letters, 24(22):2801-2804 (1997).

Transport of the deepest water westward through a gap at 28°S in the NinetyEast Ridge between the Central Indian Basin and the West Australia Basin is calculated from hydrographic data collected as part of the WOCE Hydrographic Program section I8N. Zero reference velocity levels at mid-depth were chosen through consideration of water masses. The small transport of 1.0 Sv westward through the gap of water denser than sigma₄ = 45.92 kg/m³ must all upwell in the southern Central Indian Basin. Of this, 0.7 Sv upwells between the central and western sill sections, that is, close to the sill itself. Using the areas covered by the isopycnal, we calculate an average vertical velocity of 3.3 × 10^-3 cm/s close to the sill and of 4.2 × 10^-4 cm/s west of the sill. Associated average vertical diffusivities are 10⁵ cm²/s close to the sill and 13 cm²/s west of the sill, in this very near bottom layer.

McCartney, M.S., R.G. Curry, and H.F. Bezdek. The interdecadal warming and cooling of Labrador Sea Water. ACCP Notes, 1-10 (1997).

No abstract.

McLeish, W., D.V. Hansen, and J.R. Proni. Coastal currents induced by Hurricane Andrew. Florida Scientist, 60(4):254-264 (1997).

Ocean current meters in 18 and 24 m depth water along the southeast Florida coast recorded water motions as Hurricane Andrew crossed the narrow continental shelf with the storm center 32 km from the southernmost current meter. Wind speeds up to 48 m s^-1 at the meter closest to the storm path were associated with recorded mean current speeds up to 94 cm s^-1. The greatest water speeds, however, were transient motions from the wind waves. These motions caused major changes to the bottom and to objects lying on it. Direct and remotely sensed observations showed an increasing degree of turbulence in the water as the hurricane approached, stirring both air bubbles and bottom sediment throughout the water and mixing the water so that vertical shear in the current was suppressed. Thus, beneath the strong wind stress there was not a mean water flow in the direction of the wind at the surface and a flow in the opposite direction near the bottom, as had been indicated in previous studies. Some of the water that had been forced toward shore by the strong west moving wind in the hurricane eyewall moved northward along the coast. In a region where the wind speed was less but still of hurricane force, water was displaced offshore contrary to the direction of the wind stress. At the same time that the offshore current developed, wave motions became much more severe: it appears that the new countercurrent may have induced major hurricane waves to break in this farther offshore location.

Mielke, P.W., K.J. Berry, C.W. Landsea, and W.M. Gray. A single-sample estimate of shrinkage in meteorological forecasting. Weather and Forecasting, 12(4):847-858 (1997).

An estimator of shrinkage based on information contained in a single sample is presented and the results of a simulation study are reported. The effects of sample size, amount, and severity of nonrepresentative data in the population, inclusion of noninformative predictors, and least (sum of) absolute deviations and least (sum of) squared deviations regression models are examined on the estimator. A single-sample estimator of shrinkage based on drop-one cross-validation is shown to be highly accurate under a wide variety of research conditions.

Molinari, R.L., D.A. Mayer, J.F. Festa, and H.F. Bezdek. Multi-year variability in the near surface temperature structure of the midlatitude western North Atlantic Ocean. Journal of Geophysical Research, 102(C2):3267-3278 (1997).

Between 1966 and 1995, subsurface temperature data have been collected in the western North Atlantic Ocean using expendable bathythermographs. Data coverage is sparse in both time and space, but evidence for decadal variability in the upper 400 m of the water column is found. The data were averaged by month onto a 2 degree of latitude by 4 degree of longitude grid. Thirty-one quadrangles in the region bounded by 17°N and 43°N and 78°W and 66°W have sufficient data to provide consistent results. Anomaly time series at 0, 100, 200, 300, and 400 m were estimated by subtracting a mean monthly climatology. The individual records were detrended and filtered to highlight the longer period signals. The analysis resulted in 25-year records (1969-1993) for study. Within the thermocline of the subtropical gyre and the Gulf Stream at 100 and 200 m, periods of predominately positive temperature anomaly end in 1971, 1982, and 1990, while periods of negative anomaly end in 1976 and 1985. Only the events ending in 1971, 1976, and 1990 are in the majority of the records at 300 and 400 m. Most of the events also appear in the sea surface temperature (SST) records, but are somewhat masked by significant noise at the surface. Meridional-vertical temperature sections through the subtropical gyre show that transitions from negative to positive anomaly events are characterized by a deepening of the isotherms throughout the section and transitions from positive to negative events by a rising of the isotherms. Significant lateral migration of the axis of the Gulf Stream, although possibly masked by the 2 degree averaging, is not necessary to explain either type of event. The transitions in the SST and 100 m temperature time series occur at essentially the same time as the transitions in an index of the North Atlantic Oscillation (NAO) that has also been detrended (i.e., 1971, 1976, 1980, 1984, 1988). The 1971, 1976, and 1988 NAO events are also observed at 300 and 400 m as described earlier. Periods of positive (negative) subsurface temperature anomaly are coincidental with periods of positive (negative) NAO index. Thus, earlier results showing connections between the NAO and western Atlantic SST at decadal time scales are now extended to at least 400 m in the water column. Trends were computed from the individual 25-year records. The trends at all depths are predominately negative (positive) north (south) of 38°N. Inferences from the horizontal distribution of the trends and results from earlier studies suggest that the 1969-1993 period may be a phase of a 30- to 50-year signal observed in the northern Atlantic since the beginning of the century.

Murillo, S.T., S.H. Houston, and M.D. Powell. Composites of surface marine observations for hurricanes during 1975-1996. Preprints, 22nd Conference on Hurricanes and Tropical Meteorology, Ft. Collins, CO, May 19-23, 1997. American Meteorological Society, Boston, 78-79 (1997).

No abstract.

Ooyama, K.V. Footnotes to "conceptual evolution." Preprints, 22nd Conference on Hurricanes and Tropical Meteorology, Ft. Collins, CO, May 19-23, 1997. American Meteorological Society, Boston, 13-18 (1997).

No abstract.

Ooyama, K.V. The semi-implicit integration of a nested spectral model and the result of tests in squall-line simulation. Preprints, 22nd Conference on Hurricanes and Tropical Meteorology, Ft. Collins, CO, May 19-23, 1997. American Meteorological Society, Boston, 531-532 (1997).

No abstract.

O'Sullivan, D.W., F.J. Millero, C. Goyet, E. Peltola, E.A. Degler, B. Adams, R.G.J. Bellerby, G. Eischeid, and S.J. McCue. Carbon dioxide system measurements on Arabian Sea waters. University of Miami Technical Report, RSMAS 97-005, 283 pp. (1997).

In 1995, we participated on a number of research cruises in the Arabian Sea as part of the Joint Global Ocean Flux Study (JGOFS) sponsored by the National Science Foundation (NSF). This report gives the results of our total inorganic carbon dioxide (TCO₂), total alkalinity (TA), and potentiometric pH measurements made on Arabian Sea waster samples during these cruises. The MIAMI titration system was used to determine pH, TA and TCO₂ for the waters studied. More reliable TCO₂ results were obtained using the WHOI coulometric system and these results are reported in the JGOFS data base. Measurements made on Certified Reference Material (CRM) for two different batches of CRM were used to monitor the performance of the potentiometric and coulometric CO₂ measurements. The reproducibility of the coulometry measurements of TCO₂ was to � 1.2 µmol kg^-1 (N = 115). The potentiometric measurements on CRM gave a reproducibility of � 2.7 µmol kg^-1 in TCO₂, � 3.2 µmol kg^-1 in TA, and � 0.007 in pH (N = 177). The surface measurements of pH and normalized TA were quite uniform throughout the year (pH = 8.084 � 0.016, NTA = 2288 � 5 µmol kg^-1); normalized TCO₂ was more variable (NTCO₂ = 1949 � 20 µmol kg^-1). The depth profiles of pH, TA, and TCO₂ were similar to those in the Indian Ocean.

Parrish, J.R., and M.L. Black. The NOAA G-IV and the tropical cyclone environment. Preprints, 22nd Conference on Hurricanes and Tropical Meteorology, Ft. Collins, CO, May 19-23, 1997. American Meteorological Society, Boston, 123-124 (1997).

No abstract.

Powell, M.D., and S.H. Houston. Surface wind fields of 1995 Hurricanes Erin, Opal, Luis, Marilyn, and Roxanne at landfall. Preprints, 22nd Conference on Hurricanes and Tropical Meteorology, Ft. Collins, CO, May 19-23, 1997. American Meteorological Society, Boston, 90-91 (1997).

No abstract.

Proni, J.R., and T.A. Nelsen. Final Report: Deep Ocean Relocation Project, Phase II: Application of acoustical and tracer methodologies to the deep ocean relocation of dredge material. Contract Report ARPAC 558.AOO, Naval Research Laboratory, Washington, D.C., 37 pp. (1997).

One of the major challenges facing the United States today is disposal of contaminated dredged material. Inexorable economic and population pressures assure that this challenge will exist for the foreseeable future. One concept for dealing with this material is deep ocean disposal or deep ocean relocation (DOR). A key component of DOR concepts is monitoring of the geosynthetic fabric containers (GFCs), which will be used to contain the dredged material, during descent through the oceanic water column to the ocean bottom. The present report deals with the use of acoustical and tracer methodologies for monitoring DOR-associated plumes. Discussed herein is the feasibility of utilizing active acoustical systems to monitor both GFCs and any escaping plumes. A discussion of nepheloid layer characteristics of relevance to GFC detection is presented.

Proni, J.R., and R.G. Williams. Acoustic measurements of currents and effluent plume dilutions in the western edge of the Florida Current. In Acoustic Remote Sensing Applications, S.P. Singal (ed.). Narosa Publishing House, New Delhi, India, 537-550 (1997).

The Southeast Florida Outfall Experiment (SEFLOE), carried out in the western boundary of the Florida Current off southeast Florida, USA, between 1988 and 1993, was the most extensive application of acoustics to wastewater effluent studies performed in the United States. The objective was to provide a scientific basis for managerial regulations for effluent discharges. This article describes the acoustical measurements to map effluent plume distributions, and the three-dimensional current regime. Current meters were installed near each outfall near the top and bottom of the water column. An acoustic Doppler current profiler (ADCP) was deployed on the bottom in the vicinity of the outfalls. Research ships towed active acoustical systems over the diffusers. Examples are given of the outfall plume distribution and the principal current regimes. A conceptual three-dimensional model is developed to compare with observed data. The acoustical measurements are shown to serve as a surrogate for the effluent constituent distributions.

Rhoads, K.P., P. Kelley, R.R. Dickerson, T.P. Carsey, and M.L. Farmer. Composition of the troposphere over the Indian Ocean during the monsoonal transition. Journal of Geophysical Research, 102(D15):18,981-18,996 (1997).

The atmosphere over the equatorial Indian Ocean is a unique environment in which to study the chemical and radiative effects of an intense source of anthropogenic emissions from the northern hemisphere directly coupled to the relatively pristine background conditions present in the southern hemisphere. As an initial investigation into the role of the intertropical convergence zone (ITCZ) on interhemispheric transport of pollutants, a number of trace atmospheric species were measured aboard the National Oceanic and Atmospheric Administration (NOAA) R/V Malcolm Baldrige between Durban, South Africa, and Colombo, Sri Lanka, from March 12 to April 22, 1995. Sharp increases in the concentrations of carbon monoxide (CO), carbon dioxide (CO₂), and aerosols were associated with four distinct meteorological regimes transected by the cruise track from 33°S to 9°N. Across the ITCZ, aerosol concentrations, including non-sea-salt sulfate, nitrate, and ammonium, increased by a factor of 4. Surface zone measurements showed a latitudinal gradient with a minimum near the equator and a strong diurnal variation in the equatorial regions. The latitudinal profile of gas-phase reactive nitrogen paralleled ozone and was higher in the remote southern hemisphere than in the remote northern hemisphere. Evidence of direct anthropogenic impact on the region was observed more than 1500 km from the southern tip of India. Back trajectories, calculated with NOAA's medium range forecast data using the Hybrid Single Particle Lagrangian Integrated Trajectory (HY- SPLIT) program, identified the origin of the air mass regimes characterized by the trace gas and aerosol data. Continental emissions in the northern hemisphere were shown to have a major impact on the radiative properties and oxidizing capacity of the marine atmosphere.

Rogers, R.F. A component of tropical cyclogenesis: Convective redevelopment within a warm-core mesovortex. Preprints, 22nd Conference on Hurricanes and Tropical Meteorology, Fort Collins, CO, May 19-23, 1997. American Meteorological Society, Boston, 555-556 (1997).

No abstract.

Samsury, C.E., M.L. Black, P.P. Dodge, and R.E. Orville. Utilization of airborne and NEXRAD data in the analysis of cloud-to-ground lightning in 1995 and 1996 tropical cyclones. Preprints, 22nd Conference on Hurricanes and Tropical Meteorology, Ft. Collins, CO, May 19-23, 1997. American Meteorological Society, Boston, 125-126 (1997).

No abstract.

Saltzman, E.S., P.-Y. Whung, and P.A. Mayewski. Methanesulfonate in the Greenland Ice Sheet Project 2 ice core. Journal of Geophysical Research, 102(C12):26,649-26,657 (1997).

In this paper we present measurements of methanesulfonate in the Greenland Ice Sheet Project 2 (GISP2) ice core. Methanesulfonate is an atmosphere oxidation product of dimethylsulfide. The GISP2 methanesulfonate record contains information about the atmosphere loading of biogenic sulfur over the past 110 kyr and its relationship to climate change. The GISP2 data set supports the inferences made from the Renland ice core from Greenland that the glacial atmosphere over Greenland had reduced concentrations of biogenic sulfur compared with the present day (Hansson and Saltzman, 1993). We conclude that the flux of biogenic sulfur from the North Atlantic Ocean must have been lower during glacial times and speculate that this decrease may have been related to differences in phytoplankton speciation. The data suggest that changes in direct radiative forcing from biogenic sulfur aerosols would act as negative feedback to the glacial/interglacial climate cycles in this region.

Shapiro, L.J., and J.L. Franklin. Potential vorticity and hurricane motion. Preprints, 22nd Conference on Hurricanes and Tropical Meteorology, Ft. Collins, CO, May 19-23, 1997. American Meteorological Society, Boston, 156-157 (1997).

No abstract.

Slansky, C.M., R.A. Feely, and R.H. Wanninkhof. The stepwise linear regression method for calculating anthropogenic CO₂ invasion into the North Pacific Ocean. In Biogeochemical Processes in the North Pacific, S.Tsunogai (ed.). Japan Marine Science Foundation, 70-79 (1997).

No abstract.

Song, C.G., K.M. Lee, S.D. Lee, S.J. Nahm, D.K. Lee, J.M. Lewis, and R.W. Jones. The parallelization of adjoint data assimilation method for the barotropic tropical cyclone forecast model. Journal of the Korean Meteorological Society, 33(1):111-125 (1997).

The adjoint assimilation method has been used to improve the initial conditions for forecasting, but the method requires formidable computation time. In this paper, we speed up the adjoint assimilation procedure, developed by DeMaria and Jones, using a parallelized block cyclic reduction method which solves the Poisson equation. Our study indicates that variational assimilation improves the track forecast of Hurricane Elena for the 24-72 h period, but shows little or no improvement in the 12-24 h period. These results are nearly the complement of DeMaria and Jones' result, which indicated improvements out to about 48 h but were detrimental beyond 48 h.

Stecher, H.A., G.W. Luther, D.L. MacTaggart, S.O. Farwell, D.R. Crosley, W.D. Dorko, P.D. Goldan, N. Beltz, U. Krischke, W.T. Luke, D.C. Thornton, R.W. Talbot, B.L. Lefer, E.M. Scheuer, R.L. Benner, J. Wu, E.S. Saltzman, M.S. Gallagher, and R.J. Ferek. Results of the Gas-Phase Intercomparison Experiment (GASIE): Overview of experimental setup, results and general conclusions. Journal of Geophysical Research, 102(D13):16,219-16,236 (1997).

Seven techniques for the field measurement of trace atmospheric SO₂ were compared simultaneously over one month in 1994 using samples produced in situ by dynamic dilution. Samples included SO₂ in dry air, in humid air, and in air with potentially interfering gases added. In addition, two days of comparison using diluted ambient air were conducted. Six of the seven techniques compared well, with good linear response and no serious interferences but with a range of calibration differences of about 50%.

Takahashi, T., R.A. Feely, R.F. Weiss, R.H. Wanninkhof, D.W. Chipman, S.C. Sutherland, and T.T. Takahashi. Global air-sea flux of CO₂: An estimate based on measurements of sea-air pCO₂ difference. Proceedings, National Academy of Science, USA 94:8292-8299 (1997).

Approximately 250,000 measurements made for the pCO₂ difference between surface water and the marine atmosphere, DELTApCO₂, have been assembled for the global oceans. Observations made in the equatorial Pacific during El Niño events have been excluded from the data set. These observations are mapped on the global 4° × 5° grid for a single virtual calendar year (chosen arbitrarily to be 1990) representing a non-El Niño year. Monthly global distributions of DELTApCO₂ have been constructed using an interpolation method based on a lateral advection-diffusion transport equation. The net flux of CO₂ across the sea surface has been computed using DELTApCO₂ distributions and CO₂ gas transfer coefficients across sea surface. The annual net uptake flux of CO₂ by the global oceans thus estimated ranges from 0.60 to 1.34 Gt-C • yr^-1 depending on different formulations used for wind speed dependence on the gas transfer coefficient. These estimates are subject to an error of up to 75% resulting from the numerical interpolation method used to estimate the distribution of DELTApCO₂ over the global oceans. Temperate and polar oceans of both hemispheres are the major sinks for atmospheric CO₂, whereas the equatorial oceans are the major sources for CO₂. The Atlantic Ocean is the most important CO₂ sink, providing about 60% of the global ocean uptake, while the Pacific Ocean is neutral because of its equatorial source flux being balanced by the sink flux of the temperate oceans. The Indian and Southern Oceans take up about 20% each.

Talley, L.D., and M.O. Baringer. Preliminary results from WHP sections I8N/I5E in the central Indian Ocean. Geophysical Research Letters, 24(22):2789-2792 (1997).

The R/V Knorr departed Colombo, Sri Lanka on March 10, 1995 and arrived in Fremantle, Australia on April 15, 1995 to carry out its third WOCE hydrographic leg in the Indian Ocean. Basic technical support was provided by Scripps Institution of Oceanography's Oceanographic Data Facility. Acoustic Doppler current profiler (ADCP) operations were carried out by the University of Hawaii (Firing). The basic sampling program was accomplished very smoothly. The full cruise report can be obtained from the author. The cruise track is shown in the overview figure for this newsletter, labeled I8N and I5E. The latter portion was a nominal repeat of the 1987 section (Toole and Warren, 1993). The goals of the sampling were to obtain a section through the center of the Central Indian Basin, and to repeat the crossing of the northward flow of deep water just to the west of Australia. Particular attention was paid to a potential source of deep water for the Central Indian Basin, through a sill in the NinetyEast Ridge, located at about 28°S. It was also possible to deviate from the 32°S section, and sample in the deep water south of Broken Ridge instead of along the top of the ridge. Between Broken Ridge and Australia we chose to move the section slightly north of the original position of I5E in order to resolve whether the deep flow splits around Dirck Hartog Ridge. All stations were to within 10 m of the bottom and included a 36-bottle rosette/CTD cast with lowered ADCP. A ship-mounted ADCP was operated throughout. Basic station spacing was 30 nmi, and was reduced at the equator, Sri Lankan, and Australian coasts and crossings of the NinetyEast and Broken Ridges. The CTD data stream consisted of elapsed time, pressure, two temperature channels, conductivity, oxygen, altimeter, and transmissometer signals. Water samples were collected for analyses of salt, oxygen, silica, phosphate, nitrate, and nitrite on all stations and of CFC-11, CFC-12, carbon tetrachloride, helium-3, helium-4, tritium, AMS C14, pCO₂, total dissolved inorganic carbon, alkalinity, and barium on selected stations. Water sample results were compared with preliminary data acquired on prior WOCE legs and with earlier data. The comparisons are available in the cruise report and show that the WOCE data collected on legs 1 through 3 are a uniform data set; they also show significant differences from Geosecs salinity and phosphate which are attributable to measurement precision.

Thacker, W.C., and R. Lewandowicz. A comparison of low-dimensional representations of sea-surface temperature anomalies in the North Atlantic. International Journal of Climatology, 17(9):953-967 (1997).

Correlation-matrix principal components of North Atlantic sea-surface temperature anomalies for the interval 1950-1970 account for the anomalous variability observed during the interval 1972-1992 better than do similar numbers of covariance-matrix principal components, regional averages, or carefully selected local anomalies. When drift in the seasonal cycle is taken into account, local anomalies for the 127 6° × 4° longitude-by-latitude North Atlantic cells could be recovered with an average skill as high as 0.79. Surprisingly, skill increased monotonically with increasing numbers of principal components, and the maximum value was not obtained until 62 were used to characterize the field. Clearly, far more principal components carry useful information about local details than has been previously suspected.

Thacker, W.C., and R. Lewandowicz. Partitioning the North Atlantic into regions of similar seasonal sea-surface temperature anomalies. International Journal of Climatology, 17(1):3-23 (1997).

Mean sea-surface temperatures were computed within 127 6° × 4° longitude-by-latitude cells comprising most of the North Atlantic for 171 three-month seasons from 1950 through 1992, the mean seasonal cycle was removed, and cells with correlated seasonal anomalies were clustered into regions of coherent thermal behavior. Clustering algorithms consistently produced smaller thermal regions in the vicinity of the Gulf Stream, and while the regions were generally contiguous, a disjoint region was consistently found near the Grand Banks. Examining within-region variability as a function of the number of regions revealed no obvious "best" number of regions. For 26 regions, correlations between pairs of cells within a common region were typically 0.7; for 13 regions, a sizeable fraction were less than 0.5; and for only seven regions, within-region correlations were distributed fairly uniformly between 0.2 and 0.8.

Vaughan, S.L., and R.L. Molinari. Temperature and salinity variability in the Deep Western Boundary Current. Journal of Physical Oceanography, 27(5):749-761 (1997).

A ten-year time series (1984-1993) of repeat hydrographic sections from offshore Abaco Island, the Bahamas (26.5°N), is used to define the mean and time dependent characteristics of the Deep Western Boundary Current (DWBC). The DWBC flow is divided into four vertical layers based on chlorofluorocarbon (CFC) concentration and formations regions (upper layer, CFC core, theta ~ 3.9-5.0°C; second layer, classical Labrador Sea Water, theta ~ 3.2-3.9°C; third layer, CFC minimum, theta ~ 2.4-3.2°C; deepest layer, CFC core, theta ~ 1.85-2.4°C). Time series analysis of mean layer properties and their anomalies showed that the temperature and salinity of each layer did not increase or decrease monotonically with time. Variations in temperature and salinity were characterized by two to three-year period oscillations. Variability between years is illustrated by subtracting repeat sections of temperature and salinity along levels of both constant pressure and constant potential density. To determine an original water mass modification that could be responsible for the observed variability in the section differences, an analytical method, which uses both types of differencing schemes, was applied to the DWBC data. Variability in the upper layer between 1987 and 1993 was shown to originate primarily from an increased salinity of the source waters for this layer. Variability in the second layer was shown to arise from a combination of cooling and salinification. Variability in the two deepest layers seemed to be almost entirely due to vertical movement of the isopycnals. Increases in potential temperature and salinity observed in a sublayer of the second layer defined by sigma_1.5 ~ 34.68-34.74 (classical Labrador Sea Water) from 1991 to 1993 was shown to be mainly the result of cooling. It is suggested that this cooling may have originally occurred in the central Labrador Sea during the period of active deep water renewal in the early 1970s.

Wanninkhof, R.H., G. Hitchcock, W.J. Wiseman, G. Vargo, P.B. Ortner, W.E. Asher, D.T. Ho, P.Schlosser, M.-L. Dickson, R. Masserini, K. Fanning, and J.-Z. Zhang. Gas exchange, dispersion, and biological productivity on the west Florida shelf: Results from a Lagrangian tracer study. Geophysical Research Letters, 24(14):1767-1770 (1997).

A Lagrangian tracer study was performed on the west Florida shelf in April 1996 using deliberately injected trace gases. Although such studies have been performed previously, this work is the first where the deliberate tracers, in conjunction with carbon system parameters, are used to quantify changes in water column carbon inventories due to air-sea exchange and net community metabolism. The horizontal dispersion and the gas transfer velocity were determined over a period of 2 weeks from the change in both the concentrations and the concentration ratio of the two injected trace gases, sulfur hexafluoride (SF₆) and helium-3 (³He). Horizontal diffusion estimates were about an order of magnitude greater than calculated from empirical equations, and the difference is attributed to vertical shear. The second moment of the patch grew to 1.6 × 10³ km² over a period of 11 days. The gas transfer velocity, normalized to CO₂ exchange at 20°C, was 8.4 cm hr^-1 at an average wind speed, U₁₀, of 4.4 m s^-1 for the duration of the experiment, which is in good agreement with empirical estimates. Remineralization rates exceeded productivity, causing an increase in dissolved inorganic carbon of about 1 µmol kg^-1 day^-1 in the water column. During this period of senescence, 80% of the increase in inorganic carbon is attributed to community remineralization and 20% due to invasion of atmospheric CO₂. This net remineralization is in accordance with in situ and on-deck incubation experiments.

Weisberg, R.H., and C. Wang. A western Pacific oscillator paradigm for the El Ni�o-Southern Oscillation. Geophysical Research Letters, 24:779-782 (1997).

A data-based hypothesis is presented on the mechanism of the El Ni�o-Southern Oscillation (ENSO), a major determinant of interannual global climate variability. The hypothesis emphasizes the importance of off-equator sea surface temperature and sea level pressure variations west of the dateline for initiating equatorial easterly winds over the far western Pacific. These winds compete with westerly winds over the equatorial central Pacific enabling the coupled ocean-atmosphere system to oscillate. Consistent with this hypothesis, an analogical oscillator model is constructed that produces ENSO-like oscillations. The proposed mechanism differs from the delayed oscillator paradigm in that wave reflection at the western boundary is not a necessary condition for the coupled ocean-atmosphere system to oscillate.

Weisberg, R.H., and C. Wang. Slow variability in the equatorial west-central Pacific in relation to ENSO. Journal of Climate, 10(8):1998-2017 (1997).

Six years of upper ocean velocity, temperature and surface wind data collected in the west-central Pacific at 0°, 170°W reveal a slow ocean dynamical mode associated with the El Ni�o-Southern Oscillation (ENSO). Latent and sensible heat flux calculations using the basin-wide Tropical Atmosphere Ocean (TAO) array data show a coincident, slow ocean-atmosphere thermodynamical mode. Beginning with the La Ni�a conditions in 1988 through the peak El Ni�o conditions in 1992, the Equatorial Undercurrent (EUC) speed decreased along with the surface zonal wind stress and the zonal pressure gradient. Simultaneous with these were increasing trends in the Richardson number above the EUC core and in sea surface temperature (SST). After peak warming was achieved the variations in all of these quantities reversed in a movement toward their previous La Ni�a conditions. As this evolved within the ocean the sensible and latent heat fluxes increased with large values emanating eastward from the western Pacific. The largest interannual perturbations, then, for both the surface momentum and heat flux quantities during this recent ENSO cycle were within the west-central Pacific, the transition region between the warmest waters found in the western Pacific warm pool and the coldest waters found in the eastern Pacific cold tongue. The observed ocean and atmosphere variability represents a positive feedback. This raises a question about the origin of negative feedback that is necessary for the coupled system to oscillate. Arguing from the standpoint of a Gill atmosphere and observed SST/sea level pressure correlation patterns, the paper draws a connection between condensation heating in the equatorial west-central Pacific and easterly winds over the equatorial western Pacific during the mature phase of El Ni�o. The formation of such easterlies by ocean-atmosphere coupling over the western Pacific is hypothesized as providing a negative feedback for reversing the sign of anomalous SST in the equatorial central Pacific. This mechanism may complement, but it is different from, the delayed oscillator mechanism for ENSO.

Willis, P.T., P.P.Dodge, F.D. Marks, D. Smith, and D. Churchill. Evaluation of the accuracy of the NEXRAD radar rainfall estimates in tropical summer convective rainfall over the Everglades/Florida Bay. Preprints, 22nd Conference on Hurricanes and Tropical Meteorology, Ft. Collins, CO, May 19-23, 1997. American Meteorological Society, Boston, 679-680 (1997).

No abstract.

Willoughby, H.E. More about hurricane eye thermodynamics. Preprints, 22nd Conference on Hurricanes and Tropical Meteorology, May 19-23, 1997, Ft. Collins, Colorado. American Meteorological Society, Boston, 96-97 (1997).

No abstract.

Wilson, W.D., and W.E. Johns. Velocity structure and transport in the Windward Islands Passages. Deep-Sea Research, Part I, 44(3):487-520 (1997).

During 1991-1994, repeated measurements of current structure and water mass properties were made in the major southern passages to the Caribbean Sea between Trinidad and Dominica. A total of 10 cruises were performed in different seasons, consisting primarily of serial station occupations in the Grenada, St. Vincent, St. Lucia, and Dominica Passages. This data set is by far the most comprehensive available in these passages and better determines the mean flow and range of variability than do previous studies. The flow structure in these passages is characterized by a strong and relatively stable inflow above the thermocline (approximately the upper 100 m), and a more highly variable flow regime within and below the thermocline. Typical near-surface inflow velocities in Grenada and St. Vincent passages were 40-60 cm/s, with maximum observed currents of 90 cm/s. Frequently, counterflows were observed below this surface layer flowing out of the Caribbean, trapped to the southern side of the passages. This subsurface counterflow appeared to be strongest and most prevalent in Grenada Passage, where outflow speeds as large as 30 cm s^-1 were observed.

Yvon-Lewis, S.A., and J.H. Butler. The potential effect of oceanic biological degradation on the lifetime of atmospheric CH₃Br. Geophysical Research Letters, 24(10):1227-1230 (1997).

We use a global, coupled ocean-atmosphere box model to examine the potential effect that biological degradation and its distribution can have on the lifetime of atmospheric CH₃Br. The results of this study show that both the value of the oceanic degradation rate constant and its global distribution are important in determining the calculated atmospheric lifetime. The "best" estimate of the partial lifetime of atmospheric CH₃Br with respect to oceanic loss now comes to 1.7-1.8 y with a full possible range of 0.85-3.7 y, which, together with other, non-oceanic losses, yields a total atmospheric lifetime of 0.7 y (0.5-0.9 y). A subsequent revision of the budget for atmospheric CH₃Br indicates that estimated sinks of CH₃Br today exceed estimated sources by about 90 Gg y^-1.

Zhang, J.-Z. Distinction and quantification of carry-over and sample interaction in gas segmented continuous flow analysis. Journal of Automatic Chemistry, 19(6):205-212 (1997).

The formulae for calculation of carry-over and sample interaction are derived for the first time in this study. A scheme proposed by Thiers et al. (two samples of low concentration followed by a high concentration sample and low concentration sample) is verified and recommended for the determination of the carry-over coefficient. The derivation demonstrates that both widely used schemes of a high concentration sample followed by two low concentration samples, and a low concentration sampled followed by two high concentration samples, actually measure the sum of the carry- over coefficient and sample interaction coefficient. A scheme of three low concentration samples followed by a high concentration sample is proposed and verified for determination of the sample interaction coefficient. Experimental results indicate that carry-over is a strong function of cycle time and a weak function of ratio of sample time to wash time. Sample dispersion is found to be a function of sample time. Fitted equations can be used to predict the carry-over, absorbance, and dispersion given sample times, and wash times for an analytical system. Results clearly show the important role of intersample air segmentation in reducing carry-over, sample interaction, and dispersion.

Zhang, J.-Z., and G.A. Berberian. Method 366.0: Determination of dissolved silicate in estuarine and coastal waters by gas segmented continuous flow colorimetric analysis. In Methods for the Determination of Chemical Substances in Marine and Estuarine Environmental Matrices, Second Edition. U.S. Environmental Protection Agency, EPA-600-R-97-072, 13 pp. (1997).

No abstract.

Zhang, J.-Z., P.B. Ortner, and C.J. Fischer. Method 353.4: Determination of nitrate and nitrite in estuarine and coastal waters by gas segmented continuous flow colorimetric analysis. In Methods for the Determination of Chemical Substances in Marine and Estuarine Environmental Matrices, Second Edition. U.S. Environmental Protection Agency, EPA-600-R-97-072, 20 pp. (1997).

No abstract.

Zhang, J.-Z., P.B. Ortner, C.J. Fischer, and L.D. Moore. Method 349.0: Determination of ammonia in estuarine and coastal waters by gas segmented continuous flow colorimetric analysis. In Methods for the Determination of Chemical Substances in Marine and Estuarine Environmental Matrices, Second Edition. U.S. Environmental Protection Agency, EPA-600-R-97-072, 16 pp. (1997).

No abstract. **1996**

Asher, W.E., and R.H. Wanninkhof. The effect of breaking waves on the analysis of dual-tracer gas exchange measurements. Proceedings, Third International Symposium on Air-Water-Gas Transfer, Heidelberg, Germany, July 24-27, 1995. Aeon Verlag and Studio, 517-528 (1996).

The dual-gaseous tracer technique is a new and reliable method for directly measuring air-sea gas transfer velocities. However, analysis of data from these experiments requires the assumption that the dependence of the transfer velocity on molecular diffusivity is constant. Modeling and laboratory studies indicate that this could be an invalid assumption when gas transfer through bubbles generated by breaking waves is a significant portion of the sea-to-air gas flux. Here, a parameterization of the transfer velocity in terms of wind speed and fractional area whitecap coverage is developed that includes the effects of bubble-mediated exchange processes. It is shown that transfer velocities estimated using this parameterization are consistent with available oceanic gas exchange measurements. The parameterization is then used to investigate the consequences of including whitecap-related transfer processes in the analyses of data derived from dual-tracer experiments. In the case of the tracer pair, sulfur hexafluoride and helium-3, it is shown that assuming a constant diffusivity dependence underestimates transfer velocities of helium-3 by up to 20% at high wind speeds. It is also shown that using the parameterization to normalize the transfer velocity for helium-3 to carbon dioxide results in a 6% decrease in the estimated transfer velocity compared to constant-diffusivity dependence estimates.

Asher, W.E., B.J. Higgins, L.M. Karle, P.J. Farley, C.R. Sherwood, W.W. Gardiner, R.H. Wanninkhof, H. Chen, T.P. Lantry, M. Steckley, E.C. Monahan, Q. Wang, and P.M. Smith. Measurements of gas transfer, whitecap coverage, and brightness temperature in a surf pool: An overview of WABEX-93. Proceedings, Third International Symposium on Air-Water-Gas Transfer, Heidelberg, Germany, July 24-27, 1995. Aeon Verlag and Studio, 205-216 (1996).

Toward a method for estimating air-sea gas transfer velocities, k_L, from remote measurements of fractional area whitecap coverage, W_C, a gas exchange experiment was conducted in an outdoor surf pool during the October 1993 Wave Basin Experiment (WABEX-93). For both spilling and plunging breaking waves, measurements were made of W_C; air-water fluxes of carbon dioxide, helium, nitrous oxide, oxygen, and sulfur hexafluoride; microwave brightness temperature of the water surface, sigma; aqueous-phase turbulence velocities; and bubble size spectra. The data show that k_L, scales as a common, linear relation with W_C for both spilling and plungin breaking waves. The gas transfer data have been used to develop an empirical parameterization for predicting k_L from W_C, Schmidt number, and solubility.

Bishop, J.R., and W.P. Dammann. Cabling and mooring a remotely operated ADCP for real-time data acquisition. Proceedings, Ocean 96 MTS/IEEE, Ft. Lauderdale, Florida, September 23-26, 1996. Marine Technological Society, Vol. 1, 116-119 (1996).

As part of a joint U.S. Army Corps of Engineers, Port of Miami, State of Florida, U.S. EPA, University of Miami (Rosenstiel School), National Oceanic and Atmospheric Administration (NOAA) offshore dredged material disposal program, a real time current monitoring system (RTCMS) was designed by the Ocean Acoustics Division (OAD) of the Atlantic Oceanographic and Meteorological Laboratory (AOML) for deployment offshore of Miami. This system consists of an acoustic Doppler current profiler (ADCP) moored on the ocean floor at a point southwest of the Offshore Dredge Material Disposal Site (ODMDS) and cabled to a nearshore site. The nearshore site chosen was a range marker at the Miami Harbor entrance. From the range marker the data is transmitted via radio modem to the NOAA/AOML/OAD offices on Virginia Key. The high current regime and the requirement for periodic maintenance of the ADCP added unique challenges to the design of the cable and mooring system. Cable selection and routing was performed so as to minimize risk of damage due to recreational activities. For purposes of deployment and serviceability, the cabling and mooring system was divided into three sections. The first section extends from the range marker to a common point in 60 feet of water. The cable was laid and anchored in sandy areas where possible in order to avoid reef impact. The second section connects the common point to the first mooring point at a depth of 400 feet. The final section couples the first mooring point to the ADCP mooring point. The ADCP mooring section consists of a two-point moor with a subsurface center float to suspend the cable above the bottom. The deployment of the system was accomplished in two days on board a 95-foot research vessel equipped with a stern mounted A-frame and deck winches. Divers were utilized to attach the cable to anchors in the shallow water sections, and to inspect the cable after installation.

Black, M.L., R.W. Burpee, and F.D. Marks. Vertical motion characteristics o f tropical cyclones determined with airborne Doppler radial velocities. Journal of the Atmospheric Sciences, 53(13):1887-1909 (1996).

Vertical motions in seven Atlantic hurricanes are determined from data recorded by Doppler radar on research aircraft. The database consists of Doppler velocities and reflectivities from vertically pointing radar rays collected along radial flight legs through hurricane centers. The vertical motions are estimated throughout the depth of the troposphere from the Doppler velocities and bulk estimates of particle fallspeeds. Portions of the flight tracks are subjectively divided into eyewall, rainband, stratiform, and "other" regions. Characteristics of the vertical velocity and radar structure are described as a function of altitude for the entire data set and each of the four regions. In all of the regions, more than 70% of the vertical velocities range from -2 to 2 m s^-1. The broadest distribution of vertical motion is in the eyewall region where ~5% of the vertical motions are >5 m s^-1. Averaged over the entire data set, the mean vertical velocity is upward at all altitudes. Mean downward motion occurs only in the lower troposphere of the stratiform region. Significant vertical variations in the mean profiles of vertical velocity and reflectivity are discussed and related to microphysical processes. In the lower and middle troposphere, the characteristics of the Doppler-derived vertical motions are similar to those described in an earlier study using flight-level vertical velocities, even though the horizontal resolution of the Doppler data is ~750 m compared to ~125 m from the in-situ flight-level measurements. The Doppler data are available at higher altitudes than those reached by turboprop aircraft and provide information on vertical as well as horizontal variations. In a vertical plane along the radial flight tracks, Doppler up- and downdrafts are defined at each 300-m altitude interval as vertical velocities whose absolute values continuously exceed 1.5 m s^-1, with at least one speed having an absolute value greater than 3.0 m s^-1. The properties of the Doppler drafts are lognormally distributed. In each of the regions, updrafts outnumber downdrafts by at least a factor of 2 and updrafts are wider and stronger than downdrafts. Updrafts in the eyewall slope radially outward with height and are significantly correlated over larger radial and vertical extents than in the other three regions. If the downwind (tangential) slope with height of updrafts varies little among the regions, updrafts capable of transporting air with relatively large moist static energy from the boundary layer to the upper troposphere are primarily in the eyewall region. Downdrafts affect a smaller vertical and horizontal area than updrafts and have no apparent radial slope. The total upward or downward mass flux is defined as the flux produced by all of the upward or downward Doppler vertical velocities. The maximum upward mass flux in all but the "other" region is near 1-km altitude, an indication that boundary-layer convergence is efficient in producing upward motion. Above the sea surface, the downward mass flux decreases with altitude. At every altitude, the total net mass flux is upward, except for the lower troposphere in the stratiform region where it is downward. Doppler-derived up- and downdrafts are a subset of the vertical velocity field that occupy small fractions of the total area, yet they contribute a substantial fraction to the total mass flux. In the eyewall and rainband regions, for example, the Doppler updrafts cover less than 30% of the area but are responsible for >75% and >50% to the total upward mass flux, respectively. The Doppler downdrafts typically encompass less than 10% of the area yet provide ~50% of the total downward mass flux in the eyewall and ~20% of the total downward flux in the rainband, stratiform, and "other" regions.

Blackwelder, P., T. Hood, C. Alvarez-Zarikian, T.A. Nelsen, and B. McKee. Benthic foraminifera from the NECOP study area impacted by the Mississippi River plume and seasonal hypoxia. Quaternary International, 31:19-36 (1996).

Benthic foraminifera influenced by the Mississippi River plume and seasonal hypoxia were assessed from Louisiana inner-continental shelf sediment samples. Surface foraminifera assemblages were representative of in-situ populations as established by staining techniques. Community diversity and richness/evenness analyses indicate three regimes: high stress (sediment dominated), intermediate stress (hypoxia dominated), and low stress (low sediment accumulation/high oxygen). Epistominella vitrea and Buliminella morgani are useful tracers of rapid sediment accumulation rate and hypoxia. A bottom-water productivity signal west of the Mississippi River plume is indicated by benthic and planktic foraminifera abundance peaks. Surface benthic foraminifera trends are utilized to interpret changes in historical community structure from hypoxic-area sediments deposited since the turn of the century. The hypoxia-tolerant species Buliminella morgani increases markedly upcore, while hypoxia-intolerant species decrease or disappear. Diversity and dominance trends temporally correspond to a dramatic increase in U.S. fertilizer application. The results of this study have application to paleoenvironmental research spanning longer geologic timescales. The documented relationships between population structure and stressors in river-dominated marine systems may provide a useful analog for recognition of these conditions in the fossil record.

Bufkin, J.M., and U. Rivero. Real-time digital data communication system for a remotely operated ADCP. Proceedings, Ocean 96 MTS/IEEE, Ft. Lauderdale, Florida, September 23-26, 1996. Marine Technological Society, Vol. 1, 72-75 (1996).

An acoustic Doppler current profiler (ADCP) is moored adjacent to the Miami Offshore Dredged Material Disposal Site to monitor in real-time ocean currents during dredge disposal operations. The mooring site is an active shipping channel which would present a low survivability rate for surface radio communications buoys. There are also environmentally sensitive areas which prevent the direct cabling of the ADCP into shore. By combining hardwired cable and radio transmission techniques, a remote telemetry system was designed and installed at a fixed navigational marker that provides system reliability and a stable platform to work from. Most ADCP systems that provide real-time data are cabled back to a recording site which also supplies power to the ADCP down the cable. A self-powered ADCP was utilized since cabling to shore was not a viable option. This presented problems in powering the interface to the data cable and had to be overcome. Powering down the cable was limited since the telemetry unit at the other end of the cable also had to be battery powered. From the ADCP a cable was laid to the closest fixed workable point, which happened to be a navigation marker at the entrance to the Port of Miami. This cable extends approximately three miles, and proper cable drivers had to be located that would deal with this distance. At the navigation marker, a telemetry unit was designed that buffers the received data from the ADCP cable by using a micro controller, and then transmits this data by a UHF radio modem. The data is received and stored by computer at our laboratory approximately five miles away. Power consumption proved to be a major concern, since there are no available power sources at the navigation marker. The ADCP operates from its own internal battery pack, and the telemetry unit was designed to operate from batteries with solar panels to supplement the power. It is able to operate for months unattended. The system was installed in June of 1995, and has since proved to be an extremely reliable system. The design of the telemetry system has proven to be robust, and lends itself to future experiments where data must be transmitted from a remote site.

Burpee, R.W. Hurricanes. The MacMillan Encyclopedia of Earth Science, Volume 1, 467-471 (1996).

No abstract.

Burpee, R.W., J.L. Franklin, S.J. Lord, R.E. Tuleya, and S.D. Aberson. The impact of Omega dropwindsondes on operational hurricane track forecast models. Bulletin of the American Meteorological Society, 77(5):925-933 (1996).

Since 1982, the Hurricane Research Division (HRD) has conducted a series of experiments with research aircraft to enhance the number of observations in the environment and the core of hurricanes threatening the United States. During these experiments, the National Oceanic and Atmospheric Administration WP-3D aircraft crews release Omega dropwindsondes (ODWs) at 15-20 min intervals along the flight track to obtain profiles of wind, temperature, and humidity between flight level and the sea surface. Data from the ODWs are transmitted back to the aircraft and then sent via satellite to the Tropical Prediction Center and the National Centers for Environmental Prediction (NCEP), where the observations become part of the operational database. This paper tests the hypothesis that additional observations improve the objective track forecast models that provide operational guidance to the hurricane forecasters. The testing evaluates differences in forecast tracks from models run with and without the ODW data in a research mode at HRD, NCEP, and the Geophysical Fluid Dynamics Laboratory. The middle- and lower-tropospheric ODW data produce statistically significant reductions in 12-60 h mean forecast errors. The error reductions, which range from 16% to 30%, are at least as large as the accumulated improvement in operational forecasts achieved over the last 20-25 years. This breakthrough provides strong experimental evidence that more comprehensive observations in the hurricane environment and core will lead to immediate improvements in operational forecast guidance.

Carsey, T.P., M.L. Farmer, C.J. Fischer, A. Mendez, V.B. Ross, M. Springer-Young, and M.P. Zetwo. Atmospheric chemistry measurements during Leg 4, 1993 North Atlantic cruise, R/V Malcolm Baldrige. NOAA Data Report, ERL AOML-28 (PB96-162581), 137 pp. (1996).

During September 1993, AOML conducted a multi-leg cruise aboard the Malcolm Baldrige in the North Atlantic from Iceland to Miami, Florida. The objective was to evaluate the distribution and transport of tropospheric ozone and ozone precursors in the North Atlantic. The investigation was associated with the North Atlantic Regional Experiment (NARE), a component of the International Global Atmospheric Chemistry (IGAC) project. The cruise track traversed three diverse wind and chemical regimes: pristine polar westerlies, polluted westerlies, and marine southeasterlies. Along this cruise track a large suite of chemical and meteorological data were measured. These included ozone, carbon monoxide in air and surface water, NO, NO₂, Noy, peroxyacetyl nitrate, SO₂, non-methane hydrocarbons (NMHC), and aerosols. The measurements and instrumentation are described in this data report.

Cione, J.J., and S. Raman. Surface cyclone intensity forecasting within the mid-Atlantic Gulf Stream locale using pre-storm low level baroclinic indices. Preprints, AMS Conference on Coastal Oceanic and Atmospheric Prediction, Atlanta, Georgia, January 28-February 2, 1996. American Meteorological Society, Boston (1996).

No abstract.

Cione, J.J., and S. Raman. The impact of storm track on low level mesocyclonic intensification and storm structure within the Gulf Stream locale. Preprints, AMS Conference on Coastal Oceanic and Atmospheric Prediction, Atlanta, Georgia, January 28-February 2, 1996. American Meteorological Society, Boston (1996).

No abstract.

Clark, J.F., P. Schlosser, H.J. Simpson, M. Stute, R.H. Wanninkhof, and D.T. Ho. Relationship between gas transfer velocities and wind speeds in the tidal Hudson River determined by the dual tracer technique. Proceedings, Third International Symposium on Air-Water-Gas Transfer, Heidelberg, Germany, July 24-27, 1995. Aeon Verlag and Studio, 785-799 (1996).

Gas transfer velocities were determined using the dual tracer technique (³He and SF₆) for two 40-60 km reaches of the tidal Hudson River. The experiments were performed near Poughkeepsie, New York in 1993 and near Catskill, New York in 1994. During both experiments wind speeds were measured above the river. The shape of daily axial SF₆ distributions and the evolution of peak concentrations followed patterns predicted by the one-dimensional advection-diffusion equation. Mean gas transfer velocities calculated from the 1994 data using the temporal change in SF₆ inventory (4.6 ± 0.4 cm hr^-1) and the tracer ration (5.3 ± 0.2 cm hr^-1) are in good agreement, suggesting that the dual tracer technique yields reasonable results. The relationships between gas transfer velocity and wind speeds found during these experiments are very similar to those observed previously for lakes, suggesting that wind is the primary source of surface turbulence in these reaches of the tidal Hudson River. The results of the 1993 and 1994 experiments agree very well, indicating that the local geometry of the river is of secondary importance.

Dagg, M.J., E.P. Green, B.A. McKee, and P.B. Ortner. Biological removal of fine grain lithogenic particles from a large river plume. Journal of Marine Research, 54(1):149-160 (1996).

The pelagic tunicate, Oikopleura dioica, feeds by non-selectively filtering particles in the size range of 0.1-10 µm. On the continental shelf of the northern Gulf of Mexico, dominated by the Mississippi River, particulate matter in this size range contains not only microplankton but also numerous lithogenic particles. When O. dioica is abundant it dominates total zooplankton grazing. By ingesting small (<2 µm) lithogenics that effectively do not sink as separate particles, and repackaging them into larger, more rapidly sinking particles, it also significantly alters the fates of these materials and the properties of the surface waters in and around the discharge plume of the Mississippi River.

Dammann, W.P., J.M. Bufkin, U. Rivero, S.J. Stamates, and J.R. Proni. Near real-time observations of offshore current profiles and their application to dredge material disposal activities. Proceedings, Eco-Informa '96: Global Networks for Environmental Information, Lake Buena Vista, FL, November 4-7, 1996. Environmental Research Institute of Michigan, Vol. 11, 563-568 (1996).

An acoustic Doppler current profiler (ADCP) is presently located approximately 7 km east of the Miami Harbor entrance at approximately 130 m depth. This device measures profiles of the current speed and direction in the upper 50 m of the water column directly above the instrument and transmits its data to a computer on shore. These data, sent at 20-minute intervals, are utilized to determine suitability of conditions for disposal of dredge materials. The computer performs a running one-hour average of the current vectors over the 50 m interval and transmits the east- west component to a watchstander hourly via telephone pager. If the westerly component of the current vector exceeds 12 cm per second, disposal operations are suspended. As of the date of this presentation, processed profiles of the data will be available via connection to the world wide web.

Daneshzadeh, Y.-H., J.F. Festa, and R.L. Molinari. Quality control of XBT data collected in the Atlantic Ocean: 1990-1991. NOAA Data Report, ERL AOML-29 (PB97-135446), 83 pp. (1996).

Delayed mode and real-time XBT data collected in the Atlantic Ocean during 1990 and 1991 were scientifically quality controlled at NOAA's Atlantic Oceanographic and Meteorological Laboratory (AOML) and the results of the quality control are presented in detail as tables and figures.

DeMaria, M. A history of hurricane forecasting for the Atlantic basin, 1920-1995. In Historical Essays on Meteorology, 1919-1995, J.R. Fleming (ed.). American Meteorological Society, Boston, 263-305 (1996).

The history of hurricane forecasting for the Atlantic basin from 1920-1995 is reviewed. The focus is on the forecast problem of estimating storm tracks and intensities, although other aspects of the hurricane warning process are mentioned when appropriate. Technological advances including in the implementation of the upper-air network in the late 1930s, the establishment of routine aircraft reconnaissance in the 1940s, the advent of numerical weather prediction beginning in the 1950s, and the availability of satellite observations starting in the 1960s, and their impact on hurricane forecasting are reviewed. Organizational changes in the hurricane forecast offices and the interaction between the research and forecast communities are also described. Specific forecast cases are presented to illustrate the improvements and limitations of hurricane forecasting. The outlook for the future is also discussed.

DeMaria, M. The effect of vertical shear on tropical cyclone intensity change. Journal of the Atmospheric Sciences, 53(14):2076-2087 (1996).

The effect of vertical shear on tropical cyclone intensity change is usually explained in terms of "ventilation" where heat and moisture at upper levels are advected away from the low-level circulation, which inhibits development. A simple two-level diagnostic balance model is used to provide an alternate explanation of the effect of shear. When the upper layer wind in the vortex environment differs from that in the lower layer, the potential vorticity (PV) associated with the vortex circulation becomes tilted in the vertical. The balanced mass field associated with the tilted PV pattern requires an increased midlevel temperature perturbation near the vortex center. It is hypothesized that this midlevel warming reduces the convective activity and inhibits the storm development. Previous studies have shown that diabatic heating near the storm center acts to reduce the vertical tilt of vortex circulation. These studies have also shown that there is an adiabatic process which acts to reduce the vertical tilt of a vortex. The effectiveness of the adiabatic process depends on the Rossby penetration depth, which increases with latitude, horizontal scale, and vortex amplitude. Large-scale analyses from the 1989-1994 Atlantic hurricane seasons are used to show that high-latitude, large, and intense tropical cyclones tend to be less sensitive to the effect of vertical shear than low-latitude, small, and weak storms.

Dietrich, D.E., M.J. Bowman, C.A. Lin, and A.M. Mestas-Nunez. Numerical studies of small island wakes in the ocean. Geophysical and Astrophysical Fluid Dynamics, 83:195-231 (1996).

Two and three-dimensional oceanic flows around small islands patterned after Barbados, West Indies (13 deg10 min N latitude: 59 deg 30 min W longitude) were modeled numerically to investigate island wake effects. The two-dimensional simulations closely agreed with laboratory flows, for both attached and shedding wake regimes. As expected, results for a flat bottom confirmed that the Coriolis terms strongly affect pressure but not the flow. For idealized, yet typical incident flow speeds, water column stratification, island topography, and appropriate Coriolis terms, three-dimensional simulations readily produced elongated wake patterns, dominated by surface intensified von Karman-like vortices. Effects of grid resolution, viscosity, bathymetry, and Coriolis forces on wake characteristics were studied. For islands with typical bottom slopes, realistically small horizontal eddy diffusivity has a minor effect compared to bottom drag in generating vorticity. Near-shore bathymetry (viz., the absence or presence of a continental shelf surrounding the island) plays a major role in determining the scale, intensity, and shedding period of vortices. The addition of a 15 km wide continental shelf around the island increased the shedding period by 67%, while reducing the Coriolis force by 50% reduced the shedding period by only 14%. Although observational data is sparse, inferred flow patterns do show von Karman-like structures near Barbados, even if eddies are not located exactly as expected. The numerical computations demonstrate that shedding eddy wakes are easily generated, and lend encouragement to the further search for organized wakes downstream of the island.

Duncombe Rae, C.M., S.L. Garzoli, and A.L. Gordon. The eddy field of the southeast Atlantic Ocean: A statistical census from the Benguela Sources and Transports (BEST) project. Journal of Geophysical Research, 101(C5):11,949-11,964 (1996).

Data collected during the Benguela Sources and Transports project were examined to determine some statistical properties of the eddy field observed in the Cape Basin. Seven anticyclonic eddies were encountered during the hydrographic surveys. Two of these were shown to be of Brazil Current origin (this paper and Smythe-Wright et al., 1996). Inverted echo sounder (IES) records of acoustic travel time were scaled to the depth of the thermocline, represented in the Cape Basin by the 10°C isotherm. These records indicate that a minimum of four to six eddies, assumed to be of Agulhas origin, entered the Cape Basin per year during the sampling period. They were associated with depressions in the 10°C isotherm records ranging from 100 to 400 m and of a duration between 30 and 100 days. The thermocline appears to shallow appreciably after the passage of an eddy before relaxing to the local mean. Estimates of the heat and salt contents of the hydrographically surveyed eddies indicated that the mean available heat and salt anomalies of the eddies were 0.55 × 10²⁰ J and 3.5 × 10¹² kg, respectively. Extrapolating the hydrographic data to the eddies detected in the IES record shows the eddy field responsible for the transfer of 2.2 to 3.3 × 10²⁰ J y^-1 (0.007 PW), 14 to 21 × 10¹² kg salt yr^-1, and 2 .6 to 3.8 × 10⁶ m³ s^-1.

Enfield, D.B. Relationships of inter-American rainfall to tropical Atlantic and Pacific SST variability. Geophysical Research Letters, 23(23):3305-3308 (1996).

Area-averaged anomalies of sea surface temperature (SSTA) and rainfall, developed from large-scale data sets, have been used to explore the relative importance of Pacific versus Atlantic SST variability for inter-American (50°S-50°N) climate variability at interannual time scales. SSTA in the tropical Pacific and tropical North Atlantic are comparably related to rainfall north of 15°S, with clear associations distributed between the southeastern United States (US) in the north and northern South America in the south. Although NINO3 explains 25% of the variance of the North Atlantic SSTA index, the rainfall correlations with North Atlantic SSTA are for the most part opposite in sign to those with NINO3. Hence, a significant part of the Atlantic SSTA probably has a direct association with rainfall, rather than being merely an indirect proxy for Pacific ENSO linkages. In contrast to the North Atlantic, South Atlantic SSTA appear to be only related to rainfall in northeast (NE) Brazil. The entire region between Venezuela and NE Brazil appears to be sensitive to both the ITCZ and to antisymmetric configurations of SSTA across the ITCZ, in a manner consistent with the relationships between SST, surface wind and surface wind divergence fields, and with previous studies.

Enfield, D.B., and D.A. Mayer. Relationships of western hemisphere rainfall to tropical Atlantic and Pacific SST variability. Preprint Volume, 8th Conference on Air-Sea Interaction and Symposium on the Global Ocean-Atmosphere-Land System (GOALS), Atlanta, GA, January 28-February 2, 1996. American Meteorological Society, Boston, 390-394 (1996).

No abstract.

Ffield, A., and A.L. Gordon. Tidal mixing signatures in the Indonesian Seas. Journal of Physical Oceanography, 26(9):1924-1937 (1996).

Expressions of low-frequency tidal periods are found throughout the Indonesian Seas' temperature field, supporting the hypothesis that vertical mixing is enhanced within the Indonesian Seas by the tides. The thermal signatures of tidal mixing vary mostly at the fortnightly and monthly tidal periods due to nonlinear dynamics redistributing tidal energy into these periods. Away from the coasts, the largest tidal mixing signatures are observed in sea surface temperature within the Scram and Banda Seas. Most of the Indonesian Throughflow passes through the Banda Sea where strong vertical mixing modifies the thermocline by transferring surface heat and freshwater to deeper layers before the upper water column is exported to the Indian Ocean. Modulation of vertical eddy fluxes within the Indonesian Seas by fortnightly and monthly tides may act to regulate ocean-atmosphere fluxes.

Forbes, C., and O. Brown. Assimilation of sea surface height data into an isopycnic ocean model. Journal of Physical Oceanography, 26(7):1189-1213 (1996).

Two different methods for assimilating sea surface height data into an isopycnic primitive equation model were developed and tested for the idealized case of an analytical Gaussian warm core (anticyclonic) eddy, then implemented using remotely sensed data from the BrazilMalvinas confluence region. The first method makes a geostrophic assumption about the flow to relate sea surface height field gradients to the model velocities. The second method nudges the model sea surface height itself toward the observed values using a linear vertical influence function in the upper layers. The relationship between the surface height observations and the layer interface displacements is derived from observations of eddies in different regions of the Atlantic Ocean. Both assimilation methods were successful in transferring the dynamical influence of the sea surface height measurements deep into the water column, but a combination of both gave the best results. The application of both methods reproduced the detailed mesoscale features of the real oceanic circulation when assimilating Geosat sea surface height measurements from the BrazilMalvinas confluence region into an isopycnic "box" ocean model. The velocity fields show deep anticyclonic (cyclonic) circulations of 66 cm s^-1 (52 cm s^-1), which are present in observations of eddies and meanders. When compared to the no assimilation run, the assimilated sea surface height field exhibits a richer spectrum, with energy in all spectral bands strongly correlated with the observed values. The resulting band of energy higher than 150 cm² between 300 and 600 km is in agreement with previous studies of this region. The rms error between the model sea surface height and the Geosat data was reduced from 13 cm in the no assimilation run to 2 cm rms after the assimilation. These experiments demonstrate the flexibility and effectiveness of the Newtonian relaxation (nudging) method for assimilating real data into a complex, multilayer primitive equation ocean model.

Franklin, J.L., S.E. Feuer, J. Kaplan, and S.D. Aberson. Tropical cyclone motion and surrounding flow relationships: Searching for beta gyres in Omega dropwindsonde datasets. Monthly Weather Review, 124(1):64-84 (1996).

In 1982, the National Oceanic and Atmospheric Admininstration's Hurricane Research Division began a series of experiments to collect Omega dropwindsonde (ODW) observations within about 1000 km of the center of tropical cyclones. By 1992, 16 ODW datasets had been collected in ten Atlantic basin hurricanes and tropical storms. Objective wind analyses for each dataset, at ten levels from 100 mb to the surface, have been produced using a consistent set of analysis parameters. The objective analyses, which resolve synoptic-scale features in the storm environment with an accuracy and confidence unattainable from routine operational analyses, have been used to examine relationships between a tropical cyclone's motion and its surrounding synoptic-scale flow. Tropical cyclone motion is found to be consistent with barotropic steering of the vortex by the surrounding flow within 3° latitude (333 km) of the cyclone center. At this radius, the surrounding deep-layer mean flow explains over 90% of the variance in vortex motion. The analyses show vorticity asymmetries that strongly resemble the beta gyres common to barotropic models, although other synoptic features in the environment make isolation of these gyres from the wind fields difficult. A reasonably strong relationship is found between the motion of the vortex (relative to its large scale surrounding flow) and the absolute vorticity gradient of the vortex environment.

Garzoli, S.L. SACC: South Atlantic Climate Change. U.S. Department of Commerce, NOAA/Atlantic Oceanographic and Meteorological Laboratory, Miami, Florida, 27 pp. (1996).

No abstract.

Garzoli, S.L., and A.L. Gordon. Origins and variability of the Benguela Current. Journal of Geophysical Research, 101(C1):879-906 (1996).

A subset of the Benguela Sources and Transports (BEST) 1992-1993 data is analyzed to study the magnitude and variability of the large-scale transports in the area. The data consist of inverted echo sounder series and CTD stations. The mean 16-month transport values for the upper 1000 m indicate that of the 13 Sv northward transport within the Benguela Current, 50% is derived from the central Atlantic (which from geometry may be chiefly South Atlantic water), 25% comes from the Indian Ocean (which may be chiefly Agulhas water), and the remaining 25% may be a blend of Agulhas and tropical Atlantic water. A simple schematic of the transport pattern in which a somewhat restricted corridor for Agulhas eddies translation is envisioned. To the west of the eddy corridor flows the South Atlantic source for the Benguela Current; to the east is the Agulhas (Indian Ocean) source. The corridor is breached by South Atlantic and Indian Ocean water as the transient eddy field stirs these water masses.

Garzoli, S.L., A.L. Gordon, V.M. Kamenkovich, D. Pillsbury, and C.M. Duncombe Rae. Variability and sources of the southeastern Atlantic circulation. Journal of Marine Research, 54(6):1039-1071 (1996).

The 1992-1993 Benguela Sources and Transport (BEST) time series provides a quantitative view of Benguela Current transport and the eddy field across 30°S, as well as an estimate of the relation between its barotropic and baroclinic components. This is done by a simultaneous analysis of all the different data sets: inverted echo sounders, pressure sensors, CTD, current meter moorings, and ADCP. The analysis of the time series indicate that the annual mean baroclinic transport of the Benguela Current is approximately 13 Sv. The total transport is 16 Sv. The stationary flow associated with the Benguela Current is mostly confined along the African Continent while a transient flow, composed by large eddies shed from the Agulhas retroflection, composes the western portion of the flow. In the stationary part of the Benguela Current, both barotropic and baroclinic components are equally important while in the transient part, the barotropic is more substantial. Several eddies were observed during the experiment that translates to the west. They start with a speed of 12 km/day and close to the Walvis Ridge it has already diminished to 6-7 km/day. It can be assumed that after crossing the Walvis Ridge, due to their strong barotropic component (they feel the bottom), the speed decreases to that estimate previously obtained in the middle of the basin. The sources of the Benguela Current may include Indian and South Atlantic subtropical thermocline water; the relatively saline, low oxygen tropical Atlantic water and the cooler, fresher subantarctic water. The South Atlantic thermocline and subantarctic inflow is derived from the eastward flowing South Atlantic Current. The Indian Ocean water is injected into the Benguela Current through the Agulhas retroflection eddy and filament processes. A complex stirring effect of contrasting water types is envisioned. The changes in thermocline salinity correlate with transport: in general, when the northward transport is increasing the thermocline salinity also increases. This indicates that the Benguela Current increases in strength by bringing in more subtropical water. As the Agulhas input is most effective in boosting the salinity of the upper thermocline (the South Atlantic Current water being deficient in salinity relative to the Indian Ocean source), we suggest that the spatial variations in transport are tied to Agulhas water influx, presumably within and associated with the eddy field.

Goldenberg, S.B. Are we seeing the beginning of a long-term upturn in Atlantic basin major activity? Catastrophe Reinsurance: Predictions and Protections, New York City, NY, November 7-8, 1996. American Conference Institute, section 3, 33 pp. (1996).

No abstract.

Goldenberg, S.B. Where we are at in forecasting seasonal Atlantic basin tropical cyclone activity. Final Report, Expert Meeting on Public Weather Services and Hurricane Disaster Preparedness, Port-of-Spain, Trinidad and Tobago, December 11-15, 1995. South African Weather Bureau, 5 pp. (1996).

Most of the tropical cyclones in the North Atlantic basin (including the North Atlantic Ocean, Caribbean Sea, and Gulf of Mexico) form from easterly (African) wave disturbances. Although the number of easterly waves in the tropical Atlantic tends to be fairly steady from year to year, the fraction of these that develop into tropical cyclones exhibits substantial interannual variability. Not only the number, but also the strength and location of the Atlantic basin tropical cyclones vary greatly from year to year. The Atlantic basin, unlike the east and west Pacific basins, in the mean, is not particularly favorable for tropical cyclone development. Year-to-year changes in the large-scale environment have a substantial influence on the overall activity of each Atlantic hurricane season. The search for conditions that result in the development or nondevelopment of the waves into tropical cyclones has been the subject of numerous studies, some of which have attempted to relate the variability to fluctuations in the tropical and global climate. Some of the climatic indicators that have been associated with fluctuations in Atlantic basin hurricane activity include sea-surface temperature (SST) anomalies for the equatorial central and eastern Pacific (i.e., El Ni�o activity), SSTs for the tropical Atlantic, rainfall variations over west Africa, the stratospheric Quasi-Biennial Oscillation (QBO), and vertical wind shear over the tropical Atlantic. Various studies have examined some of these indicators in an attempt to establish the actual physical mechanisms responsible for the associations with tropical cyclone activity. Other work has used selected parameters to predict Atlantic basin activity as much as 6-11 months in advance. Information will be presented describing the various parameters and their possible physical association with Atlantic hurricane activity. Current methodology used by other investigators to make seasonal predictions of activity and a discussion of their past performance will be presented with a special emphasis on implications for the Caribbean. The extended-range forecast for the 1996 Atlantic seasonal hurricane activity and Wverifications for the 1995 seasonal forecast will be discussed. The strengths and weaknesses of the current state of seasonal forecasting will be presented. The implications of fluctuations in hurricane activity on the multi-decadal scale will also be discussed.

Goldenberg, S.B., and L.J. Shapiro. Physical mechanisms for the association of El Niño and west African rainfall with Atlantic major hurricane activity. Journal of Climate, 9(6):1169-1187 (1996).

Physical mechanisms responsible for the contemporaneous association, shown in earlier studies, of North Atlantic basin major hurricane (MH) activity with western Sahelian monsoon rainfall and an equatorial eastern Pacific sea surface temperature index of El Niño are examined, using correlations with 200- and 700-mb level wind data for the period 1968-1992. The use of partial correlations isolates some of the relationships associated with the various parameters. The results support previous suggestions that the upper- and lower-level winds over the region in the basin between ~10°N and 20°N where most MHs begin developing and critical determinants of the MH activity in each hurricane season. In particular, interannual fluctuations in the winds that produce changes in the magnitude of vertical shear are one of the most important factors, with reduced shear being associated with increased activity and stronger shear with decreased activity. The results show that most of these critical wind fluctuations are explained by their relationship to the SST and rainfall fluctuations. Results confirm previous findings that positive (warm) eastern Pacific SST and negative (drought) Sahelian rainfall anomalies are associated with suppressed Atlantic basin tropical cyclone activity through an equatorially confined near-zonal circulation with upper-level westerlies and lower-level easterlies that act to increase the climatological westerly vertical shear in the main development region. SST and rainfall anomalies of the opposite sense are related to MH activity through a zonal circulation with upper-level easterly and lower-level westerly wind anomalies that act to cancel out some of the climatological westerly vertical shear. The results also show that changes in vertical shear to the north of the main development region are unrelated to, or possibly even out of phase with, changes in the development region, providing a possible physical explanation for the observations from recent studies of the out-of-phase relationship of interannual fluctuations in MH activity in the region poleward of ~25°N with fluctuations in activity to the south. The interannual variability of MH activity explained by Sahel rainfall is almost three times that explained by the eastern Pacific SSTs. It is demonstrated that a likely reason for this result is that SST-associated vertical shears are more equatorially confined, so that the changes in shear in the main development region have a stronger association with the rainfall than with the SSTs.

Goni, G.J., S. Kamholz, S.L. Garzoli, and D.B. Olson. Dynamics of the Brazil/Malvinas Confluence based on inverted echo sounders and altimetry. Journal of Geophysical Research, 101(C7):16,273-16,289 (1996).

We use data from the GEOSAT altimeter and from ten inverted echo sounder (IES) moorings deployed in the southwest Atlantic Ocean off the Argentine continental shelf to investigate several aspects of the dynamics of the upper layer in the Brazil/Malvinas Confluence region. We use the altimeter data to estimate the sea-height anomalies at each IES location, and the IES data to compute the upper-layer thickness, taken in this work to go to the depth of the 8°C isotherm. We first discuss the sea height and upper-layer thickness variations caused by the passage of the Brazil Current, Malvinas Current, and warm anticyclonic and cold cyclonic eddies. We introduce a two-layer model in which we decompose the sea height into its baroclinic and barotropic contributions. We then propose a method to monitor the thickness of the upper layer and the barotropic and baroclinic transports as a function of the sea-height anomalies and the statistics of the upper-layer thickness and reduced gravity for the region. We compute the reduced gravity values from the slope of a linear fit between the sea-height anomalies and the upper-layer thicknesses. We estimate the reduced gravity values for this region to range from 0.005 to 0.011 m s^-2. We also estimate the mean barotropic sea-height difference using two methods: conservation of mass and conservation of potential vorticity. Finally, we compute the time series for the baroclinic and barotropic transports during the GEOSAT Exact Repeat Mission (ERM) time period. Our results suggest that the mean baroclinic transport in the upper layer decreases from 12 Sv at around 35°S to 7 Sv at 37°S. Our results also indicate that there is a significant barotropic contribution to the upper-layer transport in the Confluence region.

Hacker, P., E. Firing, W.D. Wilson, and R.L. Molinari. Direct observations of the current structure east of the Bahamas. Geophysical Research Letters, 23(10):1127-1130 (1996).

Quasisynoptic absolute velocity sections were obtained in the western North Atlantic to the east of the Bahamas on five cruises from 1992 to 1994, showing complex spatial and temporal variability of the currents throughout the water column. Lowered acoustic Doppler current profilers were used on all cruises; for comparison, an acoustically-tracked free-fall profiler was used on the August 1992 and June 1993 cruises. Where simultaneous profiles from both methods are available, depth-averaged differences are less than 0.01 m s^-1 in the ensemble mean and standard deviation. Though small, the mean difference appears to be statistically non-zero for one of the two Doppler profilers used; no cause has been found. The individual velocity sections show a banded structure of currents in the offshore direction with strong baroclinic and depth-averaged components extending over the full sampling domain. Two sections show a picture of the southward-flowing Deep Western Boundary Current (DWBC) differing from previous observations. During August 1992 and June 1993 the mean DWBC core was located more than 100 km offshore; in observations prior to 1990 it was usually near 50 km offshore. Net southward transport below 800 m integrated from the coast to 400 km offshore varied from 15 to 50 Sv with a mean of about 40 Sv (1 Sv = 1 × 10⁶ m³ s^-1). Our mean is consistent with previous estimates; our sections add new evidence that the transport is highly variable to at least 400 km offshore.

Halliwell, G.R., and D.A. Mayer. Frequency response properties of forced climatic SST anomaly variability in the North Atlantic. Journal of Climate, 9(12):3575-3587 (1996).

Frequency response properties of North Atlantic (5-57°N) sea surface temperature anomaly (T_sa) variability over periods of several months to 20 years are characterized using the Cooperative Ocean Atmosphere Data Set (COADS). Significant direct forcing of T_sa variability by the anomalous wind field (primarily through the resulting anomalous surface turbulent heat flux) is observed in the Western Wind and Trade Wind belts, but not between these belts within the interior of the oceanic subtropical gyre. To analyze the response to this forcing, it is necessary to separate the total anomalous surface turbulent heat flux into a component representing the wind forcing and a component predominantly representing the negative linear feedback (Newtonian relaxation) that is the dominant damping mechanism of large-scale climatic T_sa variability. At frequencies where wind forcing is important, good agreement exists between frequency response properties estimated from data and properties theoretically predicted by a simple linearized slab mixed layer temperature balance. In particular, this balance quantifies the influence of negative feedback damping on the amplitude and phase lag of the response. In the Westerlies, wind forcing is effective over periods from several months to 8 yr, primarily 2-4 yr, and is ineffective at periods of 8-20 yr where forcing by variable oceanic flow has been demonstrated to be important. In the Trades, wind forcing is effective over periods from 8 mo to 13.3 yr, primarily 2-3 yr and 7-13.3 yr. Wind forcing in the Trades is less effective at periods of 3-6 yr where ENSO variability is significant. At frequencies where wind forcing in the Westerlies is significant, forcing and feedback have an equally large influence on T_sa, indicating that the wind-forced response is damped primarily by the negative feedback contained in the anomalous surface turbulent heat flux. In the Trades, feedback by anomalous surface turbulent heat flux is not large enough to balance the wind forcing; other processes must contribute significantly to the damping there. At frequencies where wind forcing is important, T_sa in the Westerlies is not coherent with T_sa in the Trades. The anomalous wind fluctuations driving T_sa in the Westerlies (Trades) are associated with anomalous surface pressure variability in the Icelandic low (subtropical high). Response to a coherent North Atlantic Oscillation (Icelandic Low varying out-of-phase with the subtropical high) is, therefore, not observed. The large T_sa fluctuations observed in the western basin within the Westerly Wind belt propagate to the east and northeast across the Atlantic at a characteristic speed of 6 km day^-1.

Hansen, D.V., and H.F. Bezdek. On the nature of decadal anomalies in North Atlantic sea surface temperature. Journal of Geophysical Research, 101(C4):8749-8758 (1996).

North Atlantic sea surface temperature data from the Comprehensive Ocean-Atmosphere Data Set (COADS) were used to investigate the behavior of temperature anomalies on multiple-year time scales during the period 1948-1992. Monthly anomaly time series for each 2° square from the equator to 70°N were low-pass filtered at four years and normalized by the local standard deviation. Attention is focused on the extreme events, the upper and lower deciles, of the anomaly time series. A 45-year sequence of January maps shows the already familiar phenomena of generally cold conditions prior to 1951, a long warm interval from 1951 through 1967, and again a cold period from 1968 through 1977. The years 1978 through 1982 were largely devoid of persistent strong anomalies, but moderate cold conditions returned during 1983-1986. Warm cnoditions dominated the North Atlantic from 1987 onward. Within these thermal epochs, however, a total of five cold anomaly features and nine warm anomaly features have been identified. These features have individual lifetimes of three to ten years. A typical size is 20° of latitude or longitude, but they range from barely detectable to spanning the width of the basin, the latter especially in lower latitudes. Most of the anomalies move long distances along certain preferred paths. These paths generally follow the routes of the subarctic and subtropical gyres. Anomalies originating off North America along the boundary between the gyres move northeastward toward the Norwegian Sea along the approximate route of the North Atlantic Current. Midlatitude anomalies originating at the eastern boundary tend to spread both northward and southward along the coast. The speed of these movements (1-3 km d^-1) is generally less than the expected speed of the near-surfce ocean circulation. Simple ideas about the effects of beta dynamics and air-sea heat exchanges are briefly considered but do not provide a satisfactory explanation for the movements of the anomalies. The long time scale of these extreme events and the continuity of their movements suggest a useful degree of predictability of sea surface temperature based on persistence and propagation of features.

Hansen, D.V., and P.M. Poulain. Quality control and interpolations of WOCE/TOGA drifter data. Journal of Atmospheric and Oceanic Technology, 13(4):900-909 (1996).

Satellite-tracked drifting buoy data are being collected by numerous investigators and agencies in several countries for the WOCE/TOGA Surface Velocity Program. By the end of the century and thereafter this global data set will provide the definitive climatology and chronology of the surface currents of the world ocean. To expedite completion of research quality data sets for archival and dissemination, a data acquisition activity is being conducted at NOAA/AOML, Miami, Florida. At AOML data from drifting buoys of cooperating operators are quality controlled and optimally interpolated to uniform six-hour interval trajectories for archival at the Marine Environmental Data Service (Canada). This report describes in detail the procedures used in preparing these data for the benefit of second or third party users, or future buoy operators who may wish to process data in a consistent way. Particular attention is given to provide quantitative estimates for uncertainty of interpolation.

Hansen, D.V., and M.S. Swenson. Mixed layer circulation during EqPac and some thermochemical implications for the equatorial cold tongue. Deep-Sea Research, Part II, 43(4-6):707-724 (1996).

Surface currents inferred from satellite-tracked drifting buoys were used to develop a chronology of surface currents in the central Pacific for the year encompassing the EqPac field program. Salient features of the chronology are the early months of the program witnessed anomalous eastward current surges near the equator within the moderate El Niño event, followed by a period of anomalously strong westward flow near the equator and eastward flow in the North Equatorial Countercurrent that led, in mid-summer, to an eruption of tropical instability waves that continued until the end of the field program. None of these events was particularly unusual, but they were departures from climatology that influence the interpretation of the biochemical measurements made for EqPac. Results from a semi-quantitative conceptual model indicate that tropical instability waves have more important long-term, as well as short-term, consequences for thermochemical properties of the cold tongue than previously recognized.

Harris, J.E., D.B. Enfield, and N. Bravo. Altimetric assessment of the NMC ocean model. AVISO Newsletter, 4:18-20 (1996).

No abstract.

Hendee, J.C. Object-oriented analysis of a near real-time marine environmental data acquisition and reporting system. NOAA Technical Memorandum, ERL AOML-90 (PB97-114573), 69 pp. (1996).

The National Oceanic and Atmospheric Administration's Coral Health and Monitoring Program has cooperated with the Florida Institute of Oceanography in developing a near real-time marine environmental monitoring and reporting system. Using the latest in object-oriented analysis techniques, this report describes how data are retrieved from satellite data and archiving facilities, then reformatted for presentation via a remote bulletin board system and facsimile.

Hendee, J.C. Object-oriented design of a near real-time marine environmental data acquisition and reporting system. NOAA Technical Memorandum, ERL AOML-89 (PB97-114581), 35 pp. (1996).

The National Oceanic and Atmospheric Administration's Coral Health and Monitoring Program in Miami, Florida has for the last several years worked cooperatively with the Florida Institute of Oceanography in monitoring meteorological and oceanographic events at selected Coastal-Marine Automated Network sites in the Florida Straits. In a previous report, an object-oriented analysis (OOA) was conducted of the existing system with an eye toward redesigning the system. This report builds on the OOA results from the previous study and utilizes the latest in object-oriented design techniques to design a new system.

Houston, S.H., W.A. Schaffer, M.D. Powell, and J. Chen. Incorporating HRD surface wind fields into the SLOSH model. Preprints, Conference on Coastal Oceanic and Atmospheric Prediction, Atlanta, GA, January 28-February 2, 1996. American Meteorological Society, Boston, 265-267 (1996).

No abstract.

Huang, H., R.E. Fergen, J.R. Proni, and J.J. Tsai. Probabilistic analysis of ocean outfall mixing zones. Journal of Environmental Engineering, 122(5):359-367 (1996).

A methodology for ocean outfall mixing zone analysis is presented. It is based on a combination of four deterministic models for predicting hydrodynamic mixing behaviors of the discharged effluent, a continuous time domain simulation method, and an exceedance probability field concept. The approach provides a framework for evaluating mixing zones in compliance with receiving water criteria that are set in statistical terms. The approach was applied to the Hollywood outfall located off the east coast of south Florida. An exceedance probability field for effluent at a specified relative concentration of 0.021 was created. This field was applicable for determining the exceedance probability-based concentrations of any conservative pollutant at the regulatory mixing zone edge. A comparison of the probabilistic approach with the worst-case approach was made. The use of the worst-case approach was found to be too conservative for the subject outfall.

Huebert, B.J., A.A.P. Pszenny, and B. Blomquist. The ASTEX/MAGE Experiment. Journal of Geophysical Research, 101(D2):4319-4329 (1996).

The Atlantic Stratocumulus Transition Experiment/Marine Aerosol and Gas Exchange (ASTEX/MAGE) was a multinational experiment designed to study the relationship between marine chemistry, aerosols, clouds, and air/sea exchange. Several aircraft, ships, and island sites supported measurements of marine boundary layer chemistry in both pristine and polluted North Atlantic air masses in the vicinity of the Azores in June of 1992. The International Global Atmospheric Chemistry (IGAC) Program's MAGE activity organized the chemical experiments in ASTEX because such experiments are beyond the capabilities of any one platform, discipline, or nation working alone. One highlight of ASTEX/MAGE was the development of a Lagrangian experimental strategy. It offered a unique way of constraining fluxes and reaction rates by observing the effect those processes have on a tagged parcel of air.

Jensen, T.L., S.M. Kreidenweis, Y. Kim, H. Sievering, and A.A.P. Pszenny. Aerosol distributions in the North Atlantic marine boundary layer during Atlantic Stratocumulus Transition Experiment/Marine Aerosol and Gas Exchange (ASTEX/MAGE). Journal of Geophysical Research, 101(D2):4455-4467 (1996).

Marine boundary layer aerosol size distributions observed during June 1992 are described. Measurements were made from on board the National Oceanic and Atmospheric Administration ship Malcolm Baldrige in support of the Atlantic Stratocumulus Transition Experiment/Marine Aerosol and Gas Exchange field experiment in the area surrounding 32°N latitude and 25°W longitude. Measurements obtained from three instruments, the differential mobility particle sizer, the active scattering aerosol spectrometer probe, and the forward scattering spectrometer probe, were used to investigate the contributions of the different aerosol modes to total number, surface area, and volume concentrations. It was observed that aerosol populations in air masses that appear to have originated from remote marine areas have a bimodal number distribution with total number concentrations ranging from 200 to 800 particles cm^-3. In air masses that have been affected by anthropogenic emissions, the aerosol size distributions become monomodal and total number concentrations increase to 500 to 1800 cm^-3. The data also suggest that air mass boundaries can be very sharp and that there may be some mesoscale variability in the aerosol population within an air mass.

Landsea, C.W., N. Nicholls, W.M. Gray, and L.A. Avila. Downward trends in the frequency of intense Atlantic hurricanes during the past five decades. Geophysical Research Letters, 23(13):1697-1700 (1996).

There is concern that the enhanced greenhouse effect may be affecting extreme weather events such as tropical cyclones. The North Atlantic basin offers a reliable, long-term record of tropical cyclone activity, though it may not be representative of tropical cyclones throughout the rest of the tropics. The most recent years of 1991 through 1994 have experienced the quietest cyclone activity on record in terms of frequency of tropical storms, hurricanes, and intense hurricanes. This was followed by the 1995 hurricane season, one of the busiest in the past 50 years. Despite 1995's activity, a long-term (five decade) downward trend continues to be evident primarily in the frequency of intense hurricanes. In addition, the mean maximum intensity (i.e., averaged over all cyclones in a season) has decreased, while the maximum intensity attained by the strongest hurricane each year has not shown a significant change.

Mayewski, P.A., M.S. Twickler, S.I. Whitlow, L.D. Meeker, Q. Yang, J. Thomas, K. Kreutz, P.M. Grootes, D.L. Morse, E.J. Steig, E.D. Waddington, E.S. Saltzman, P.-Y. Whung, and K.C. Taylor. Climate change during last deglaciation in Antarctica. Science, 272(5268):1636-1638 (1996).

Greenland ice core records provide clear evidence of rapid changes in climate in a variety of climate indicators. In this work, rapid climate change events in the Northern and Southern hemispheres are compared on the basis of an examination of changes in atmospheric circulation developed from two ice cores. High-resolution glaciochemical series, covering the period 10,000 to 16,000 years ago, from a central Greenland ice core and a new site in east Antarctica display similar variability. These findings suggest that rapid climate change events occur more frequently in Antarctica than previously demonstrated.

McCartney, M.S., R.G. Curry, and H.F. Bezdek. North Atlantic's transformation pipeline chills and redistributes subtropical water. Oceanus, 39(2):19-23 (1996).

No abstract.

Mielke, P.W., K.J. Berry, C.W. Landsea, and W.M. Gray. Artificial skill and validation in weather forecasting. Weather and Forecasting, 11(2):153-169 (1996).

The results of a simulation study of multiple regression prediction models for meteorological forecasting are reported. The effects of sample size, amount, and severity of nonrepresentative data in the population, inclusion of noninformative predictors, and least (sum of) absolute deviations (LAD) and least (sum of) squared deviations (LSD) regression models are examined on five populations constructed from meteorological data. Artificial skill is shown to be a product of small sample size, LSD regression, and nonrepresentative data. Validation of sample results is examined, and LAD regression is found to be superior to LSD regression when sample size is small and nonrepresentative data are present.

Millero, F.J., and E. Peltola. Total alkalinity measurements in the Southern Ocean: World Ocean Circulation Experiment, Leg S4(I). University of Miami Technical Report, RSMAS 96-005, 98 pp. (1996).

In the spring and summer of 1996, we participated in a research cruise in the Southern Ocean (S4(I)) as a part of the Joint Global Ocean Flux Study (JGOFS)/World Ocean Circulation Experiment (WOCE) sponsored by the Department of Energy (DOE). This report gives the results of our pH, total alkalinity (TA), and total inorganic carbon dioxide (TCO₂) determined from potentiometric measurements during the cruise. At sea measurements made on Certified Reference Material (CRM Batch 31) using the two cells indicate that the systems have a reproducibility of � 2.7 µmol kg^-1 in TA, � 2.9 µmol kg^-1 in TCO2 and � 0.005 in pH. The TA measurements made on CRM at sea (2131 � 3 µmol kg^-1) were in good agreement with the laboratory measurements (2130 � 1.4 µmol kg^-1). The normalized values of TA (NTA = 2375 � 5 µmol kg^-1) and normalized TCO₂ (NTCO₂ = 2230 � 10 µmol kg^-1) were quite uniform for the surface waters. The deep waters had similar carbonate properties (pH = 7.60 � 0.02, TA = 2355 � 10 µmol kg^-1, TCO₂ = 2240 � 10 µmol kg^-1). Our titration results will be combined with the partial pressure of carbon dioxide (pCO₂) and total carbon dioxide (TCO₂) measurements, made by Dr. Taro Takahashi's research group from Lamont-Doherty Earth Observatory at Columbia University, to fully characterize the CO₂ system in these waters.

Napp, J.M., L.S. Inzce, P.B. Ortner, D. Siefert, and S. Britt. The plankton of Shelikof Strait as predators, prey, and competitors of larval pollock. Fisheries Oceanography, 5:19-38 (1996).

The vertical distribution of walleye pollock eggs and larvae in Shelikof Strait, Gulf of Alaska, was investigated using data from 36 Multiple Opening-Closing Net and Environmental Sensing System (MOCNESS) tows taken in April and May 1986-1988. Most eggs were found from below 150 m to near bottom, ~300 m, but were progressively shallower later in the season. Eggs in middle stages of development were shallower than younger or older eggs. The vertical distribution of eggs was positively related to observed differences in seawater temperature but showed no relationship to density. Larvae hatch at incubation depth and quickly rise to the upper 50 m of the water column where they remain during larval development. Larger larvae(~7-10 mm standard length) undergo limited diel vertical migration within the upper 50 m. They are deepest during the day, shallowest at dusk, slightly deeper at night, and even deeper at dawn. Their mean depths of occurrence were between 21 and 37 m at all times. At these depths, prey (copepod nauplii) generally were at densities sufficient for larval pollock growth in laboratory studies. Pronounced thermoclines and pycnoclines were present in the part of the water column inhabited by the larvae in late May. Larvae appear to remain below the upper mixed layer during periods of increased turbulence, but at depths during daytime where light was sufficient for feeding, and where prey densities were adequate.

Nelsen, T.A. Coastal ocean water resources: Linkages with terrestrial freshwater resources, anthropogenic influences, and climate change. In Diachronic Climatic Impacts on Water Resources, A.N. Angelakis and A.S. Issar (eds.). NATO ASI Series I: Global Environmental Change, Vol. 36, Springer-Verlag, Berlin, Heidelberg, 319-347 (1996).

No abstract.

Nelsen, T.A., M.P. Zetwo, H. Wanless, P. Blackwelder, P. Swart, T. Hood, C. Alvarez-Zarikian, J. Trefry, S. Metz, W.-J. Kang, R. Trocine, L. Tedesco, M. Capps, and M. O'Neal. The sediment record as a monitor of natural and anthropogenic changes in the lower Everglades/Florida Bay ecosystem: A high resolution study. 1996 Florida Bay Science Conference,Miami, Florida, June 1996. Florida Sea Grant/University of Florida Publication, 62-65 (1996).

No abstract.

Nystuen, J.A. Acoustic rainfall analysis: Rainfall drop size distribution using the underwater sound field. Journal of Atmospheric and Oceanic Technology, 13(1):74-84 (1996).

Rainfall estimation is difficult, especially in oceanic regions where land-based techniques are unavailable. Fortunately, rain produces a loud and unique sound underwater that can be used to detect and quantify rainfall. Laboratory studies of the sound generated by individual raindrops have provided the basis for a formal inversion of the naturally generated underwater ambient sound field. Field measurements of subtropical rainfall at the Atlantic Oceanographic and Meteorological Lab Rain Gauge Facility are used to demonstrate the forward (predicting the sound field given the rainfall drop size distribution) and the inverse problem (estimating the drop size distribution given the sound field). This acoustical rainfall analysis (ARA) algorithm was tested for several dozen rainfall events spanning six months and was found to provide excellent estimates of rainfall rate, rainfall accumulation, and rainfall reflectivity (the quantity sensed by radars). High temporal resolution (order 510 s) variations in drop size distribution within the rain can be studied using ARA.

Nystuen, J.A., J.R. Proni, P.G. Black, and J.C. Wilkerson. A comparison of automatic rain gauges. Journal of Atmospheric and Oceanic Technology, 13(1):62-73 (1996).

Automatic rain gauge systems are required to collect rainfall data at remote locations, especially oceanic sites where logistics prevent regular visits. Rainfall data from six different types of automatic rain gauge systems have been collected for a set of summertime subtropical rain events and for a set of wintertime rain events at Miami, Florida. The rain gauge systems include three types of collection gauges: weighing, capacitance, and tipping bucket; two gauges that inherently measure rainfall rate: optical scintillation and underwater acoustical inversion; and one gauge that detects individual raindrops: the disdrometer. All of these measurement techniques perform well; that is, they produce rainfall estimates that are highly correlated to one another. However, each method has limitations. The collection gauges are affected by flow irregularities between the catchment basin and the measurement chambers. This affects the accuracy of rainfall-rate measurements from these instruments, especially at low rainfall rates. In the case of the capacitance gauge, errors in 1-min rainfall rates can exceed +10 mm h^-1. The rainfall rate gauges showed more scatter than the collection gauges for rainfall rates over 5 mm h^-1, and the scatter was relatively independent of rainfall rate. Changes in drop size distribution within an event could not be used to explain the scatter observed in the optical rain gauge data. The acoustical inversion method can be used to measure the drop size distribution, allowing rainfall classification and estimation of other rain parameters, for example, reflectivity or liquid water content, in addition to rainfall rate. The acoustical inversion method has the advantage of an extremely large catchment area, resulting in very high time resolution. The disdrometer showed a large scatter relative to the other rain gauge systems for low rainfall rates. This is consistent with the small catchment area for the disdrometer system.

Palmer, D.R. Rayleigh scattering from nonspherical particles. Journal of the Acoustical Society of America, 99(4):1901-1912 (1996).

A comprehensive framework is developed for calculating the intensity received by a monostatic sonar system due to backscattering from a cloud of nonspherical particles suspended in the ocean. The cloud can consist of different types of particles having arbitrary shapes, volume distributions, and orientations, as well as an overall mass density that varies spatially within the cloud. In the Rayleigh region it is possible to average over particle orientation exactly. The averaged backscattered intensity depends on particle shape through the eigenvalues of a tensor that can, in principle, be determined by solving a boundary value problem for a harmonic function. Since the solution to this boundary value problem is out of reach practically, bounds are obtained on the backscattered intensity that are independent of particle shape. These bounds form the basis for obtaining estimates of the error that is made by assuming the particles in the cloud scatter sound as if they were spherical. A number of examples and applications are considered, the most important of which is the feasibility of a sonar to image black smoker hydrothermal plumes. The reassuring result that the spherical particle assumption is likely to lead to feasibility criteria that underestimate the performance of a sonar is obtained. The isoperimetric bounds are combined with the principle of maximum entropy, applied to the distribution of particle shapes, to obtain a new expression for the square of the amplitude for backscattering at wave number k₀ from a particle of volume V, specific bulk modulus e and a specific density h: PHI² = (k₀² V/4 pi)² [(e - 1)/e + (h² - 1)/2h]². This amplitude is obtained by averaging over particle orientation and particle shape and is to be compared to the corresponding quantity for a shere PHI_sp² = (k₀² V/4 pi)² [(e - 1)/e + (3 (h - 1))/(2h + 1)]². The use of the new expression is preferred in situations where it is known the particle shapes are quite variable and irregular and where 1.0 < h < 2.5. In all the examples considered it is found the error that results from assuming the particles scatter sound as if they were spherical is small. This is comforting and consistent with one's intuition that in the Rayleigh region the scattered sound should be somewhat insensitive to the shape of the scatterer.

Powell, M.D., S.H. Houston, and T.A. Reinhold. Hurricane Andrew's landfall in south Florida. Part I: Standardizing measurements for documentation of surface wind fields. Weather and Forecasting, 11(3):304-328 (1996).

Hurricane Andrew's landfall in south Florida left a swath of destruction, including many failed anemometer recording systems. Extreme destruction led to exaggerated claims of the range of wind speeds that caused such damage. The authors accumulated all available data from surface platforms at heights ranging from 2 to 60 m and reconnaissance aircraft at altitudes near 3 km. Several procedures were used to represent the various types of wind measurements in a common framework for exposure, measurement height, and averaging period. This set of procedures allowed documentation of Andrew's winds in a manner understandable to both meteorologists and wind engineers. The procedures are accurate to ±10% for marine and land observing platforms, and boundary layer model adjustments of flight-level winds to the surface compare within 20% of the nearest surface measurements. Failure to implement the adjustment procedures may lead to errors of 15%-40%. Quality control of the data is discussed, including treatment of peak wind observations and determination of the radius of maximum winds at the surface.

Powell, M.D., and S.H. Houston. Hurricane Andrew's wind field at landfall in south Florida. Part II: Surface wind fields and potential real-time applications. Weather and Forecasting,11(3):329-349 (1996).

All available wind data associated with Hurricane Andrew's passage were analyzed for periods corresponding to landfall south of Miami and emergence from southwest Florida. At landfall in southeast Florida, maximum sustained (1 min) surface wind speeds (V_M1) reached 62 m s^-1 in the northern eyewall over land; by the time Andrew exited the Florida peninsula, the peak value of V_M1 over land decreased to 44 m s^-1. Radar reflectivity observations from Tampa and Melbourne could not support an obvious correlation of convective cell development with coastal convergence during landfall on the southeast coast. On the southwest coast, however, convective cell development in the southern eyewall was supported by a coastal convergence maximum. Comparison of the wind swath with two independent Fujita-scale damage maps indicated that peak swath speeds compared well with speed equivalents in the worst damaged areas but were higher than equivalents in moderately damaged areas. Comparison of the analysis maximum wind swath with an engineering survey of damaged homes suggests that homes exposed to a wide range of wind directions while subjected to high wind speeds suffered the most damage. Potential real-time applications of wind field products include warning dissemination, emergency management, storm surge and wave forecasting, and wind engineering. Development of damage assessment models for disaster mitigation is addressed from the viewpoint of an electrical utility.

Proni, J.R., S.J. Stamates,and J.F. Craynock. Massachusetts Bay water column particulate horizons study. Contract Report DW13940107-01-0, U.S. Environmental Protection Agency, 33 pp. (1996).

No abstract.

Proni, J.R., W.P. Dammann, J.F. Craynock, S.J. Stamates, D. Commons, R. Fergen, H. Huang, R. Ferry, B. Goldenberg, J. Mandrup-Poulson, J. Monson, and R. Williams. Worst case effluent discharge conditions and adaptive processing of effluents for southeast Florida outfalls. Proceedings, 68th Annual Conference, WEFTEC '95, Miami Beach, FL, October 21-25, 1995. Water Environment Federation, 147-158 (1996).

Of substantial interest to entities regulating coastal ocean effluent discharges are so-called "worst case" conditions. In general, "worst case" conditions refer to conditions of poorest dilution as determined by criteria involving ambient current speed distributions. A unique feature of the coastal waters off southeast Florida is the proximity of the Florida Current or Gulf Stream, one of the most powerful oceanic currents on earth with an average daily transport through the Straits of Florida of approximately 32 × 10⁶ m³/sec. An extensive study called the Southeast Florida Outfall Experiment (SEFLOE) was carried out between 1988 and 1994 on the effluent discharges from four major southeast Florida coastal ocean outfalls. All four of these outfalls are located within the western boundary regime of the Florida Current and, therefore, pose unique challenges in determining "worst case" conditions. All four outfall sites are located in water of 30 m depth and are alternately "within" and "external to" the Florida Current. As a consequence of their locations, each of the outfalls is subject to three different ambient current and, hence, dilution regimes. These regimes are (i) site occupied by the Florida Current, (ii) site external to the Florida Current but occupied by a relatively large scale, e.g., kilometers, current eddy, or (iii) site external to the Florida Current but occupied by short-period, e.g., 3-12 hour current variations, possibly being linear and non-linear tides. "Worst case" dilution conditions in the sense of poorest initial and/or subsequent dilution are observed during the occurrence of regime (iii) above. During this regime very small mean currents are observed.

Rogers, R.F., and J.M. Fritsch. A general framework for convective trigger functions. Monthly Weather Review, 124(11):2438-2452 (1996).

A general framework for the trigger function used in convective parameterization routines in mesoscale models is proposed. The framework is based on the diagnosis of the accessibility of potential buoyant energy. Specifically, the trigger function (1) estimates the magnitude of the largest vertical velocity perturbation from a source layer, and (2) calculates the total amount of inhibition between the source layer and the level of free convection. The calculation of perturbation magnitude accounts for such factors as subgrid-scale inhomogeneities, a convective boundary layer, and convergence within the source layer. Specific formulations to quantify these factors are proposed. The trigger is tested in a simulation using the PSU-NCAR mesoscale model MM5. The event chose for simulation is a summertime case exhibiting a variety of environments. The results of the simulation are compared with a simulation using the Fritsch-Chappell (FC) trigger function. It is found that decisions made by the new trigger function are more physically consistent with the local environment than decisions made by the FC trigger.

Rogers, R.F., and J.M. Fritsch. Mesoscale modeling of weakly-forced convection: Sensitivity to surface property specification. Preprints, 11th Conference on Numerical Weather Prediction, Norfolk, VA, August 19-23, 1996. American Meteorological Society, Boston, 386-388 (1996).

No abstract.

Roux, F., and F.D. Marks. Extended velocity track display (EVTD): An improved processing method for Doppler radar observations of tropical cyclones. Journal of Atmospheric and Oceanic Technology, 13(4):875-899 (1996).

We present an improved version of the Velocity Track Display (VTD) method, proposed by Lee et al. (1994) to deduce the primary vortex circulation in hurricanes from airborne Doppler radar data obtained during straight-line legs through the storm center. VTD allows the derivation of one projection of the mean horizontal wind, the wave number 0, 1, and 2 components of the tangential wind and one projection of the radial wind, in a series of concentric rings centered on the storm circulation center. The extended VTD (EVTD) algorithm determines additional information through a combination of data collected during successive legs: the Cartesian components of the mean horizontal wind, the wave number 0, 1, and 2 components of the tangential wind, and the wave number 0 and 1 components of the radial wind. Application of EVTD to airborne Doppler data collected on 17 September 1989 in Hurricane Hugo is discussed. Comparisons between the EVTD-derived winds, the flight-level measurements, and winds deduced from "pseudo-dual Doppler" analyses show qualitatively good agreement. These results reveal the asymmetric structure of the storm and show that it was in a deepening stage, with increasing tangential wind, inflow, and upward velocity. Further applications are finally discussed.

Schott, F.A., and R.L. Molinari. The western boundary circulation of the subtropical warmwater sphere. In The Warmwater Sphere of the North Atlantic Ocean, W. Krauss (ed.). Gebrüder Borntraeger, Berlin, Stuttgart, 229-252 (1996).

Herein, we review observational, empirical, and modeling studies of the western boundary region of the North Atlantic's subtropical gyre. Emphasis is placed on recent observational studies that consider both interaction between wind-driven and thermohaline driven currents and characterize the annual and interannual time scales of the regional circulation.

Severinghaus, J.P., W.S. Broecker, T.-H. Peng, and G. Bonani. Transect along 24°N latitude of ¹⁴C in dissolved inorganic carbon in the subtropical North Atlantic Ocean. Radiocarbon, 38(3):407-414 (1996).

The distribution of bomb-produced ¹⁴C in the ocean provides a powerful constraint for circulation models of upper ocean mixing. We report ¹⁴C measurements from an east-west section of the main thermocline at 24°N latitude in the subtropical North Atlantic Ocean in summer 1992, and one profile from the Gulf of Mexico in 1993. Observed gradients reflect the transient invasion of bomb ¹⁴C into the thermocline via mixing along isopycnals from the poleward outcrop, with progressively more sluggish mixing at greater depths. A slight deepening of the profile is observed over the 20-year period since the GEOSECS survey at one location where the comparison is possible.

Shapiro, L.J. The motion of Hurricane Gloria: A potential vorticity diagnosis. Monthly Weather Review, 124(11):2497-2508 (1996).

Multilevel, multinested analyses of Hurricane Gloria of 1985 are the most comprehensive kinematic data set yet developed for a single hurricane. A piecewise inversion technique is used with these analyses and the nonlinear balance equation to deduce the three-dimensional distribution of potential vorticity (PV) that contributed to the deep-layer mean (DLM) flow that steered Hurricane Gloria toward the northwest. The background state is taken to be the azimuthally averaged winds in balance with a geopotential distribution on an f plane. Advantage is taken of the near-linearity of the weak asymmetries near the hurricane's core and of PV in the environment. Thus, ad hoc aspects of the linearization required by other investigators are effectively eliminated. Removal of the hurricane vortex and the use of a climatological mean background state are avoided as well. The insensitivity of the results to the imposed lateral boundary condition is also demonstrated. Wind anomalies attributable to pieces of anomalous PV restricted to cylinders of different radii centered on the hurricane are evaluated. The DLM wind that steered Gloria to the northwest is primarily attributable to PV anomalies confined within a cylinder of radius 1000 km and levels 500 mb and above, including positive anomalies associated with a cold low over Cuba. The vector difference between the hurricane's observed motion and the DLM wind at Gloria's center attributable to these PV anomalies is 1.0 m s^-1, explaining more than five-sixths of the hurricane's 6.2 m s^-1 motion. Implications for measurements required to establish short-term changes of the environmental steering flow are considered. Difficulties in the interpretation of results are discussed for PV anomalies that are confined to noncircular regions; the implication for other studies is considered as well.

Sirkes, Z., E. Tziperman, and W.C. Thacker. Combining data and a global primitive equation ocean general circulation model using the adjoint method. In Modern Approaches to Data Assimilation in Ocean Modeling, P. Malanotte-Rizzoli (ed.), Elsevier, Amsterdam, 119-145 (1996).

A primitive equation ocean general circulation model (PE OGCM) in a global configuration similar to that used in coupled ocean-atmosphere models is fitted to climatological data using the adjoint method. The ultimate objective is the use of data assimilation for the improvement of the ocean component of coupled models, and for the calculation of initial conditions for initializing coupled model integrations. We argue that oceanic models that are used for coupled climate studies are an especially appropriate target for data assimilation using the adjoint method. It is demonstrated that a successful assimilating of data into a fully complex PE OGCM critically depends on a very careful choice of the surface boundary condition formulation, on the optimization problem formulation, and on the initial guess for the optimization solution. The use of restoring rather than fixed surface-flux boundary conditions for the temperature seems to result in improved model results. The convergence of the optimization seems very sensitive to the cost formulation in a PE model, and a successful cost formulation is discussed and demonstrated. Finally, the use of simple, sub-optimal assimilation schemes for obtaining an initial guess for the adjoint optimization is advocated and demonstrated.

Springer-Young, M., D.J. Erickson, and T.P. Carsey. Carbon monoxide gradients in the marine boundary layer of the North Atlantic Ocean. Journal of Geophysical Research, 101(D2):4479-4484 (1996).

We present an observational data set that suggests that the ocean source of carbon monoxide (CO) may influence the atmospheric CO concentration in the marine boundary layer (MBL). Atmospheric CO concentration gradient data obtained during the 1992 Atlantic Stratocumulus Transition Experiment (ASTEX) show significantly (range of 2-47 ppbv, average of 15 ppbv) more CO at an altitude of 0.05 to 0.5 m above sea level as compared to 10 m above sea level. The seawater CO concentrations needed to support the fluxes obtained from an atmospheric gradient calculation are much higher than generally reported in the literature. However, studies of CO production by Jones and Amador (1993) and data from Seiler (1978) suggest the possibility that CO production and the resultant flux to the MBL could be 1-2 orders of magnitude higher than currently documented using seawater pumped from depths of 4-10 m below the air-sea interface. We infer that the surface ocean production and sea-air exchange of photochemically produced trace gases such as CO may participate in physical, chemical, and biological processes on vastly different spatial and temporal scales than those inherent to more stable species such as CO₂.

Stamates, S.J., J.F. Craynock, J.R. Proni, V. Fox-Norse, and D.A. Tomey. Acoustic reflector of opportunity distribution as a surrogate for inferring effluent distribution in a survey of Massachusetts Bay. Proceedings, Ocean 96 MTS/IEEE, Ft. Lauderdale, FL, September 23-26, 1996. Marine Technological Society, Vol. 1, 313-320 (1996).

In 1998, the Massachusetts Water Resources Authority (MWRA) expects to complete the construction of a new oceanic wastewater outfall system which will have the capacity to release as much as 1.2 × 10⁹ (gal) of treated wastewater per day. The design of the system is such that during summer months the effluent plume should be trapped beneath the seasonal thermocline. It is proposed that the spatio-temporal distribution of acoustic reflectors (probably biological) present in the seasonal thermocline is a reasonable surrogate for inferring the spatio-temporal distribution of acoustic reflectors that will result from the release of wastewater effluent. In September 1995, a joint U.S. EPA, MWRA, NOAA survey of Massachusetts Bay was conducted. The primary data sets gathered were acoustic backscatter profiles at 20 kHz and 200 kHz made every 0.5 (sec) with 0.5 (m) vertical resolution. Also, CTD casts and water bottle samples were taken at selected locations. Oceanographic phenomena, such as internal waves and tidal surges in conjunction with topographic features, cause the surrogate scattering layers to be vertically modulated with possible mixing of materials normally trapped within layer boundaries. Analysis of acoustic backscatter measurements provide visualizations of such events and allow for the estimation of the surrogate scattering layer distributions in the vertical and horizontal planes. Quantitative comparison of acoustic backscatter strength with CTD derived density and transmissometry measurements give an indication of the relationship of the surrogate scattering layers to the water density structure at selected sites in the study (and an indication of the reliability of the surrogate). In addition to its role as a surrogate for wastewater, the relationship of the surrogate scattering material layers with respect to the isopycnal surfaces is also considered for the purpose of evaluating the exposure of biota to future wastewater discharge.

Swenson, M.S., and P.P. Niiler. Statistical analysis of the surface circulation of the California Current. Journal of Geophysical Research, 101(C10):22,631-22,645 (1996).

We use a set of mixed-layer drifting buoy trajectories from the California Current (20°N-40°N) during 1985-1990 to obtain statistically reliable estimates of the mean currents, the mean variance field, and the geographically varying diffusivity, integral timescales, and integral space scales. Typical values for the diffusivity are 1.1-8.7 × 10⁷ cm² s^-1, while the timescales and space scales are 2.1-7.1 days and 16-59 km, respectively. The variance field displays a strong westward gradient out to 125°W, and diffusivity shows a tendency to decrease toward the southwest part of the domain. Significant anisotropy is found in the variance field near the coastal boundary and at 30°N, 130°W, which is the region where the subarctic and northern subtropical fronts approach the California Current. The antisymmetric component of the diffusivity tensor indicates that cyclonic eddies dominate the mesoscale signature of drifters in this region. We seek simple parameterizations to relate the scales of motion of the random velocity field to the diffusivity by testing least-square fits. We found no cases for which these two hypotheses could be distinguished. For the meridional component the linear regressions are not successful, which suggests that the meridional departure velocities result from a flow regime that is significantly organized by, for example, waves or coherent structures. A subset of the drifters measured temperature along their tracks, and we use the resultant data to produce the first direct estimates of the horizontal eddy heat flux divergence based on Lagrangian estimates. In addition, we separately compute the "eddy diffusivity" parameterization of the eddy heat flux divergence using our diffusivity estimates and a sea surface temperature climatology. The two independent terms agree well, which provides a measure of reassurance about the difusivity estimates. The eddy heat flux divergence in the California Current is very small (<5 W m^-2) and does not appear to be significant in the long-term heat budget of the upper ocean in this region.

Thacker, W.C. Climatic fingerprints, patterns, and indices. Journal of Climate, 9(9):2259-2261 (1996).

The purpose of this note is to point out that Hasselmann's (1993) optimal fingerprints for detecting climatic change follow from the geometrical interpretation of covariance as an inner product.

Thacker, W.C. Metric-based principal components: Data uncertainties. Tellus A, 48(4):584-592 (1996).

Seeking an index characterizing the best-determined mode of variability leads to a natural generalization of principal-component analysis with an explicit metric characterizing the uncertainties of the data. This formalism, which distinguishes between state-space patterns and patterns of coefficients defining principal components, allows the more accurate data to exert a greater influence on the definition of the indices than they do in conventional principal-component analysis; in all other aspects, the new formalism is the same as the old. Within the context of the simple example of Breterton et al. (1992), metric-based principal-component analysis is shown to be capable of finding correlated patterns of variability in two different data sets.

Thacker, W.C., and R. Lewandowicz. Climatic indices, principal components, and the Gauss-Markov theorem. Journal of Climate, 9(8):1942-1958 (1996).

If indices are to be used as the variables predicted by linear statistical models, it is important to be able to recover as much local information as possible from the values forecast for the indices. Here it is shown that the indices that encapsulate the most information about the local climatic state are determined by a generalized (two-matrix) eigenvalue problem that is equivalent to the usual (one-matrix) eigenvalue problem involving the sample correlation matrix. Thus, the best indices in the sense of providing the most location-specific information are the familiar principal-component indices. Regarding the indices as predictors in linear statistical models similar to those routinely used for estimating meteorological fields from observations reveals the role of the Gauss-Markov theorem in EOF analyses. From this perspective each index can be characterized by two EOF-like maps: the first illustrating the linear combinations of the data used to define the index, and the second displaying the Gauss-Markov weights for the index to predict local variables, both of which are related to the eigenvectors of the sample correlation matrix. Other maps can be used to display information about sampling errors: one to characterize the uncertainty of the weights; another to display the skill with which the index accounts for the training data; and a third to show how well it explains independent data. Such maps are illustrated within the context of 43 years of North Atlantic seasonal sea-surface temperature anomalies. The analysis presented here underlies two additional points. First, any linear combination of the indices would result in an equivalent model yielding exactly the same forecast. Consequently, it may be desirable to use indices that are easier to interpret physically. Second, when indices are regarded as being variables of a linear statistical model, the analysis of sampling error can be formulated in terms of the uncertainty of the Gauss-Markov weights inferred from a limited training set rather than in terms of the sample-to-sample variability of eigenvalues and eigenvectors.

Tsai, J.J., J.R. Proni, H. Huang, and J.F. Craynock. Initial and near-field subsequent dilution at the Key West Outfall. Proceedings, 68th Annual Conference, WEFTEC '95, Miami Beach, FL, October 21-25, 1995. Water Environment Federation, 139-146 (1996).

A one-year field study of discharge from the Key West Outfall was conducted from June 1993 to July 1994. A towed CTD was used to measure salinity about every other month with a fixed current mooring next to the outfall. Salinity deficit was used as a tracer to estimate the minimum surface dilution at the boil and near field subsequent dilution. The measured dilution was rapid within 200 m and reached 100:1 at about 500 m from the boil.

Wang, C., and R.H. Weisberg. Stability of equatorial modes in a simplified coupled ocean-atmosphere model. Journal of Climate, 9(12):3132-3148 (1996).

The stability, periodicity, and horizontal structure of equatorial modes in a coupled ocean-atmosphere model, simplified by the assumption that zonal wind stress anomalies are proportional to sea surface temperature (SST) anomalies lagged by a zonal phase difference, are examined analytically. The gravest coupled Rossby and Kelvin modes coexist with westward and eastward slow modes. Two of these four modes, one propagating westward and the other eastward, are destabilized in each case depending upon the model parameters. For some particular parameter choices, coupled Rossby and Kelvin modes merge with westward and eastward slow modes, respectively. For other parameters, however, they separate and remain distinct from the slow modes. For all of these modes the primary modifications by coupling relative to uncoupled oceanic equatorial waves are a decrease in phase speed and an increase in meridional scale. Among the model parameter effects, those of the zonal phase lag between the wind stress and SST anomalies and the coefficients of thermal and mechanical damping are the most interesting. The frequency of all modes is symmetric about zero phase lag, whereas the growth rate is antisymmetric relative to the uncoupled damping rate. Wind anomalies to the west of SST anomalies favor slow (coupled Rossby and Kelvin) mode growth (decay). Slow (coupled Rossby and Kelvin) mode damping is mainly thermal (mechanical). It may be concluded that coupling affects the structure, propagation, and stability properties of equatorial modes at low frequency. Determining where within the equatorial waveguide and with what efficiency coupling occurs would, therefore, seem to be critical for improved understanding of the ENSO phenomenon.

Wanninkhof, R.H., and M. Knox. Chemical enhancement of CO₂ exchange in natural waters. Limnology and Oceanography, 41(4):689-697 (1996).

Exchange of carbon dioxide (CO₂) under low turbulence conditions and high pH can be enhanced by hydration reactions of CO₂ with hydroxide ions and water molecules in the boundary layer. A series of field experiments was performed on several lakes, including alkaline closed-basin lakes, using enclosures (helmets) to study the enhancement process in nature. In addition, the enhancement of CO₂ exchange was studied in laboratory experiments using freshwater and seawater. The results of the experiments are compared with published theoretical calculations. Within the experimental uncertainties and shortcomings of the chemical enhancement models, reasonable agreement was observed between experimental and theoretical results for seawater. The experiments indicate, in accordance with theory, that chemical enhancement has a minor effect on air-sea gas exchange of CO₂ under average oceanic turbulence conditions. However, for the equatorial CO₂ source regions, with high temperatures and low winds, the calculated CO enhancement amounts to 4% to 8% of the total exchange. The observations on lakes show poorer agreement with models which is attributed to experimental uncertainty and poor characterization of the chemistry of the lake waters. The experiments show that chemical enhancement of CO₂ is ubiquitous for the alkaline close basin lakes with enhancements of up to a factor of three.

Wanninkhof, R.H. W.E. Asher, and E.C. Monahan. The influence of bubbles on air-water-gas exchange: Results from gas transfer experiments during WABEX-93. Proceedings, Third International Symposium on Air-Water-Gas Transfer, Heidelburg, Germany, July 24-27, 1995. Aeon Verlag and Studio, 239-254 (1996).

Bubble-mediated gas transfer velocities were determined in a freshwater surf pool during WABEX-93. Gas transfer of N₂O, He, and SF₆ were measured under eight different mechanically-generated, breaking-wave conditions. Contrary to gas transfer across an air-water interface, where the transfer is solely a function of surface turbulence and the molecular diffusion coefficient of the gas, exchange through bubbles is also a function of the solubility of the gas, bubble size, and bubble penetration depths. The relative rates of gas transfer through bubbles of N₂O, CO₂, He, and SF₆ for the experiment are compared with models developed by Woolf (1995) and Keeling (1992). The model of Woolf shows reasonable agreement with the observed results while that of Keeling overpredicts the exchange of N₂O. The trend suggests that in the surf pool experiments the solubility dependence of the model of Keeling is too strong while that of Woolf is slightly too weak compared to the observations.

Wanninkhof, R.H., R.A. Feely, H. Chen, C. Cosca, and P.P. Murphy. Surface water fCO₂ in the eastern equatorial Pacific during the 1992-1993 El Niño. Journal of Geophysical Research, 101(C7):16,333-16,343 (1996).

The fugacity of CO₂ in surface water (fCO_2W) was measured in the eastern equatorial Pacific (EEP) during the boreal spring and fall of 1992 and in the spring of 1993. A prolonged El Niño occurred during this period with anomalously warm sea surface temperatures (SST) during the spring of 1992 and 1993. Correspondingly, the fCO_2W values were lower than historical non-El Niño values at the equator. However, the fCO_2W in the spring of 1993 was up to 50 µatm higher than in the spring of 1992, despite similar SSTs. The trend is attributed to the slower response times of factors causing fCO_2W decrease compared to rapid increase of fCO_2W by upwelling cold water with high carbon content and subsequent heating. During the fall of 1992, SSTs south of the equator were 5°C cooler than in the spring, which is indicative of vigorous upwelling of water with high CO₂ content from below the thermocline. Decreases in fCO_2W due to net biological productivity and gas exchange take of the order of months, causing the fCO_2W levels during the spring of 1993 to be elevated compared to the spring of the previous year. Our data and data obtained in 1986 and 1989 along 110°W suggest that fCO_2W maxima in the equatorial Pacific can be either associated with temperature minima or temperature maxima. Despite the multitude of factors which influence fCO_2W, most of the variance can be accounted for with changes in nitrate and SST. A multilinear regression of fCO_2W with SST and nitrate for the 1992 data has a standard error in predicted fCO_2W of 10 µatm. Air-sea fluxes of CO₂ in the EEP were estimated to be 30% higher in the spring of 1993 and 10% higher in the fall of 1992 than in the spring of 1992.

Willoughby, H.E., and P.G. Black. Hurricane Andrew in Florida: Dynamics of a disaster. Bulletin of the American Meteorological Society, 77(3):543-652 (1996).

Four meteorological factors aggravated the devastation when Hurricane Andrew struck south Florida: completed replacement of the original eyewall by an outer, concentric eyewall while Andrew was still at sea; storm translation so fast that the eye crossed the populated coastline before the influence of land could weaken it appreciably; extreme wind speed, 82 m s^-1 winds measured by aircraft flying at 2.5 km; and formation of an intense, but nontornadic, convective vortex in the eyewall at the time of landfall. Although Andrew weakened for 12 h during the eyewall replacement, it contained vigorous convection and was reintensifying rapidly as it passed onshore. The Gulf Stream just offshore was warm enough to support a sea level pressure 20-30 hPa lower than the 922 hPa attained, but Andrew hit land before it could reach this potential. The difficult-to-predict mesoscale and vortex-scale phenomena determined the course of events on that windy morning, not a long-term trend toward worse hurricanes. **1995**

Abbott, M.R., K.H. Brink, C.R. Booth, D. Blasco, M.S. Swenwon, C.O. Davis, and L.A. Codispoti. Scales of variability of bio-optical properties as observed from near-surface drifters. Journal of Geophysical Research, 100(C7):13,345-13,367 (1995).

A drifter equipped with bio-optical sensors and an automated water sampler was deployed in the California Current as part of the coastal transition zone program to study the biological, chemical, and physical dynamics of the meandering filaments. During deployments in 1987 and 1988, measurements were made of fluorescence, downwelling irradiance, upwelling radiance, and beam attenuation using several bio-optical sensors. Samples were collected by an automated sampler for later analysis of nutrients and phytoplankton species composition which, in turn, were associated with the meandering circulation. Variance spectra of the bio-optical parameters revealed fluctuations on both diel and semidiurnal scales, perhaps associated with solar variations and internal tides, respectively. Offshore, inertial-scale fluctuations were apparent in the variance spectra of temperature, fluorescence, and beam attenuation. Although calibration samples can help remove some of these variations, these results suggest that the use of bio-optical data from unattended platforms such as moorings and drifters must be analyzed carefully. Characterization of the scales of phytoplankton variability must account for the scales of variability in the algorithms used to convert bio-optical measurements into biological quantities.

Aberson, S.D., S.J. Lord, M. DeMaria, and M.S. Tracton. Short-range ensemble forecasting of hurricane tracks. Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 494-496 (1995).

No abstract.

Atlas, D., P.T. Willis, and F.D. Marks. The effect of convective updrafts and downdrafts on reflectivity-rain rate relations and water budgets. Preprints, 27th Conference on Radar Meteorology, Vail, CO, October 9-13, 1995. American Meteorological Society, Boston, 19-22 (1995).

No abstract.

Bakker, C. Development of object-oriented software for real-time presentations and quality control of wind data in hurricanes. Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 86-88 (1995).

No abstract.

Black, M.L., R.W. Burpee, and F.D. Marks. Two-dimensional spatial structure of hurricane updrafts and downdrafts. Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 605-607 (1995).

No abstract.

Black, M.L., R.W. Burpee, and F.D. Marks. Vertical motion asymmetries in the hurricane eyewall. Preprints, 27th Conference on Radar Meteorology, Vail, CO, October 9-13, 1995. American Meteorological Society, Boston, 574-576 (1995).

No abstract.

Black, P.G., and G.J. Holland. The boundary layer of Tropical Cyclone Kerry (1979). Monthly Weather Review, 123(7):2007-2028 (1995).

The boundary layer structure of Tropical Cyclone Kerry (1979) is investigated using composite analysis of research aircraft, surface ship, and automatic weather station observations. The boundary layer was moist, convective, and strongly confluent to the east of the tropical cyclone center but was dry, subsident, and diffluent to the west. The vertical momentum transport in the eastern convective sector of Kerry was around two to three times the surface frictional dissipation. In contrast, the stable boundary layer in the western sector consisted of a shallow mixed layer capped by an equivalent potential temperature minimum and a low-level jet, which underwent a marked diurnal oscillation. Three mechanisms appear to have contributed to the observed asymmetry: (1) a general, zonal distortion arose from cyclonic rotation across a gradient of earth vorticity; (2) a westerly environmental vertical shear produced forced ascent on the east side of the storm and subsidence on the west side throughout the lower and midtroposphere; and (3) the western sector boundary layer was modified by an upstream cold tongue generated by the tropical cyclone passage. The authors present evidence that substantial drying also resulted from shear-induced mixing of the subsident environmental air in the region of the low-level jet. Thermal boundary layer budgets are derived using both a general mixing theory approach and direct flux calculations from aircraft reconnaissance data. Use of actual sea surface temperature fields are essential. The surface flux estimates of latent heat are near the average of previous studies, but the sensible heat fluxes are downward into the ocean. Since horizontal advection also cooled the boundary layer, the thermal structure was maintained by downward fluxes of sensible heat from the top of the boundary layer of around 100 W m^-2. We conclude that the pattern of oceanic cooling directly determines the pattern of vertical air-sea and advective sensible heat fluxes and indirectly determines the pattern of latent heat fluxes through forcing of PBL drying at the downwind end of the SST cold pool. It further enhances the inward penetration and negative feedback resulting from an easterly trade wind surge associated with a mobile trough in the westerlies.

Black, P.G., and L.K. Shay. Observed sea surface temperature variability in tropical cyclones: Implications for structure and intensity change. Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 603-604 (1995).

No abstract.

Black, P.G., J.R. Proni, J.C. Wilkerson, and C.E. Samsury. Classification of convective and stratiform regions in oceanic tropical and subtropical mesoscale convective systems using underwater acoustic methods. Preprints, 27th Conference on Radar Meteorology, Vail, CO, October 9-13, 1995. American Meteorological Society, Boston, 237-239 (1995).

No abstract.

Black, P.G., R. McIntosh, C. Swift, J. Carswell, K. St. Germain, I. Popstefanija, and M. Goodberlet. Ocean surface wind, stress, and rain rate measurements in tropical cyclones from concurrent airborne microwave scatterometer and radiometer observations. Preprints, 27th Conference on Radar Meteorology, Vail, CO, October 9-13, 1995. American Meteorological Society, Boston, 623-625 (1995).

No abstract.

Black, R.A., H.B. Bluestein, and M.L. Black. Unusually strong vertical motions in a Caribbean hurricane. Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 260-262 (1995).

No abstract.

Bogdanov, Y.A., E.G. Gurvich, V.M. Kuptsov, N.A. Rimskiy-Korsakov, A.M. Sagalevich, P.A. Rona, and M.D. Hannington. Relict sulfide mounds at the TAG hydrothermal field of the Mid-Atlantic Ridge (26�N, 45�W). Oceanology, 34(4):534-542 (1995).

In the course of the 23rd cruise of the R/V Akademik Mstislav Keldysh, a huge extinct hydrothermal cone-shaped mound (Mir mound) was discovered at the TAG hydrothermal field. The diameter of the mound near its base is over 700 m and its altitude is 50-70 m. The total weight of hydrothermal material is about 10 million tons. In plan, the mound has two subzones, namely, the inner and outer ones. The inner subzone diameter is about 400 m. It has a densely spaced high-temperature sulfide chimney. The older outer subzone is 150-200 m in width. It has predominantly low-temperature hydrothermal deposits, namely, hydroxides of Fe and Mn, opal, and rarely, sulfides. It is partly covered by calcareous sedimentary rocks. The radiocarbon dating of sediments sampled near the mound showed that Mir mound was set more than 25,000 years ago. Since that time, it was hydrothermally active during the following periods: 23,000-25,000, 12,000-16,000, and 4,000-8,000 years ago. Deep tow photography, side scan survey, and sediment analyses indicate the existence of another extinct hydrothermal mound of similar dimensions 2.5 km north of the Mir mound.

Broecker, W.S., S. Sutherland, W. Smethie, T.-H. Peng, and G. Ostlund. Oceanic radiocarbon: Separation of the natural and bomb components. Global Biogeochemical Cycles, 9(2):263-288 (1995).

An improved method has been developed for the separation of the natural and bomb components of the radiocarbon in the ocean. The improvement involves the use of a very strong correlation between natural radiocarbon and dissolved silica. This method is applied to radiocarbon measurements made on samples collected during the Geochemical Ocean Sections Study (GEOSECS), Transient Tracers in the Ocean (TTO) and South Atlantic Ventilation Experiment (SAVE) expeditions. On the basis of this new separation we provide not only an estimate of the global inventory of bomb ¹⁴C inventory and penetrations along thermocline isopycnals in the North Atlantic Ocean but also between the times of the GEOSECS (1972-1973) and TTO (1980-1982) surveys and in the South Atlantic Ocean between the times of the GEOSECS (1973) and SAVE (1987-1989) surveys. In addition, we show that the bomb tritium to bomb C ratio (expressed in the tritium units [TU] 81 units/100%) for waters entering the thermocline of the northern hemisphere is about nine times higher than for those entering the southern hemisphere thermocline. This contrast offers long-term potential as an indicator of inter-hemispheric transport of upper ocean waters.

Burpee, R.W., J.L. Franklin, S.J. Lord, and R.E. Tuleya. The performance of hurricane track guidance models with and without Omega dropwindsondes. Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 6-8 (1995).

No abstract.

Bushnell, M.H. Drifter news. Mariners Weather Log, 39(3):32-33 (1995).

The drifting buoys developed at Scripps and deployed by the Global Drifter Center (GDC) have measured currents and water temperature for over a decade. These small, inexpensive drifters described in previous issues of the Mariners Weather Log are ideal platforms for several other types of sensors as well. In this column the suite of sensors used and planned are discussed.

Bushnell, M.H. The global Lagrangian Drifter Data Assembly Center at NOAA/AOML. International WOCE Newsletter, 20:36-37 (1995).

No abstract.

Chen, H., R.H. Wanninkhof, R. Feely, and D. Greeley. Measurements of fugacity of carbon dioxide in seawater: An evaluation of a method based on infrared analysis. NOAA Technical Memorandum, ERL AOML-85 (PB95-271029), 54 pp. (1995).

An analysis system is described to measure the fugacity of CO₂ (fCO₂)¹ in 500 mL of seawater (discrete samples) by infrared analysis. The unit has been used on oceanographic research cruises sponsored by the Ocean-Atmosphere Carbon Exchange Study (OACES) of NOAA since 1991 for a total of approximately 10,000 measurements. The precision of the analyses based on replicate samples during routine analysis is 0.2%. Precision is primarily limited by sample storage, and the difference between headspace gas and water CO₂ concentrations prior to equilibration. The precision and accuracy of the instrument is estimated in several different ways. A preliminary side by side test of two different discrete fCO₂ systems using an infrared (IR) analyzer and a gas chromatograph (GC) shows a variability of 0.8% without significant bias. For surface waters the discrete measurements are compared with measurements from a continuous flowing underway system which was deployed on all cruises. Select comparisons with fCO₂ calculated from spectrophotometric pH and DIC (Total Dissolved Inorganic Carbon) measurements are performed. These comparisons are limited by uncertainty in the magnitude and the temperature dependence of the carbon and borate dissociation constants. Indirect comparisons are made with pCO₂ measurements of Drs. Takahashi and Chipman of LDEO in the South Atlantic and equatorial Pacific (EqPac). Although the measurements were performed months (for the EqPac study in 1992) to years (for the South Atlantic study in 1989 and 1991) apart, some inferences can be made by normalizing the fCO₂ values and by performing the comparison in property space. The comparison indicates that the precision of our system is comparable to that of the LDEO system. The surface values obtained from the LDEO system during EqPac are 1.5 to 3% lower. There is inconclusive evidence that some of the subsurface LDEO pCO₂ values are lower as well. However, the comparison of subsurface values for the North Atlantic Deep Water in the South Atlantic study shows good agreement. Because of the current uncertainty in dissociation constants, there is no a priori way to determine which value is correct.

Churchill, D.D., S.H. Houston, and N.A. Bond. The Daytona Beach wave of 3-4 July 1992: A shallow-water gravity wave forced by a propagating squall line. Bulletin of the American Meteorological Society, 76(1):21-32 (1995).

An unexpected runup of the ocean along Daytona Beach, Florida, on 3-4 July 1992 was associated with at least one large ocean wave. The wave, which reached a height of about 3 m above normal tide, injured 75 people and damaged property along Daytona Beach. Analyses of meteorological and oceanographic observations are consistent with the hypothesis that a squall line generated a long water wave. The critical evidence is that the propagation speed of the squall line matched the shallow-water wave speed that prevailed along the direction of motion of the squall line. The squall line exerted force on the ocean for at least 3 h. The issues of recurrence and public safety are discussed.

Cione, J.J., and S. Raman. A numerical investigation of surface-induced mesocyclogenesis near the Gulf Stream. Tellus A, 47:815-833 (1995).

No abstract.

Cione, J.J., S. Raman, L.J. Pietrafesa, X. Li, R.A. Neuherz, and K. Keeter. Operational utilization of the Atlantic Surface Cyclone Intensification Index (ASCII). Proceedings, American Meteorological Society Regional Training Symposium for Operational Forecasters in the Carolinas and Virginia, Raleigh, North Carolina, November 6-8 1995. American Meteorological Society, Boston (1995).

No abstract.

Clark, J.F., P. Schlosser, R.H. Wanninkhof, H.J. Simpson, W.S.F. Schuster, and D.T. Ho. Gas transfer velocities for SF₆ and ³He in a small pond at low wind speeds. Geophysical Research Letters, 22(2):93-96 (1995).

Gas transfer velocities for two gases, SF₆ (sulfur hexafluoride) and ³He, were determined in a small pond by injecting a mixture of these gases into the water and monitoring the decline of their concentrations over the next eight days. For wind speeds between 1.5-2.5 m s^-1, no variations of gas transfer velocity with wind speed could be resolved with our data. Gas transfer velocities at wind speeds greater than 3 m s^-1 were substantially larger and consistent with other lake tracer experiments. From the ratio of gas transfer velocities for SF₆ and ³He, we calculated the Schmidt number exponent to be 0.57 ± 0.07.

Crane, M.L., R.H. Smith, M.H. Bushnell, W.D. Wilson, and S. Tosini. NSWC moored ADCP data, 1994 (Straits of Florida, 26°04.00'N, 80°03.50'W). National Oceanographic Data Center, Washington, D.C., CD-ROM, NODC-59 (1995).

This database contains acoustic Doppler current profiler (ADCP) data collected during 1994 on the eastern shelf of Florida. The data were collected at 10-minute intervals by a bottom mounted 300-kHz ADCP unit (from RD Instruments, San Diego, CA), and is offshore Ft. Lauderdale, Florida, at a depth of 140 m. This instrument is positioned at approximately 26°04.0'N by 80°03.5'W. The unit is supported by the United States Naval Surface Warfare Center (NSWC), which receives binary data directly from the ADCP by way of a submerged cable. Following negotiations in 1993, a cooperative effort was established between the National Oceanic and Atmospheric Administration (NOAA) and the Naval Surface Warfare Center to forward the binary ADCP data collected by NSWC to the NOAA Atlantic Oceanographic and Meteorological Laboratory (AOML) in Miami, Florida. Since April 1994, AOML has been receiving the binary data from NSWC.

Dagg, M.J., and P.B. Ortner. Zooplankton grazing and the fate of phytoplankton in the northern Gulf of Mexico. Proceedings, 1994 Synthesis Workshop, Baton Rouge, LA, April 26-28, 1994. Louisiana Sea Grant Program, 21-27 (1995).

The copepod community consumes a significant fraction of the phytoplankton production that is stimulated by riverine nutrient inputs in the northern Gulf of Mexico. In addition, there is strong evidence that Appendicularians are important consumers of small particles (including pico-phytoplankton). The primary fate of phytoplankton production in this river-dominated shelf is to be grazed by zooplankton.

Dammann, W.P., and J.R. Proni. Fort Pierce, Florida dredge material discharge study. Contract Report, RM-CW-94-0033, U.S. Army Corps of Engineers, 6 pp. (1995).

No abstract.

Darling, R.W.R., S.H. Houston, and H.E. Willoughby. Parametric models of hurricane surface winds for storm surge calculations. Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 454-456 (1995).

No abstract.

DeMaria, M. Another look at the effect of vertical shear on tropical cyclone intensity change. Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 323-325 (1995).

No abstract.

DeMaria, M. Evaluation of hydrostatic height-coordinate formulation of the primitive equations for atmospheric modeling. Monthly Weather Review, 123(12):3576-3589 (1995).

The hydrostatic form of the primitive equations described by Ooyama is evaluated by comparing nonhydrostatic and hydrostatic integrations of a dry axisymmetric model with a specified entropy (heat) source. In this formulation, pressure is a diagnostic variable, so that the hydrostatic approximation can be included simply by replacing the vertical momentum equation with a diagnostic vertical velocity equation. This diagnostic equation is a one-dimensional (height) second-order elliptic equation that can be solved using a direct method. Results show that hydrostatic solutions are very sensitive to the accuracy of the method used to solve the diagnostic vertical velocity equation. However, this sensitivity can be eliminated by adding an extra term to the diagnostic equation that ensures that the solution does not drift away from hydrostatic balance due to numerical approximation. When the extra term is added, this formulation of the primitive equations allows for the design of a numerical model in height coordinates that can be used in hydrostatic and nonhydrostatic regimes.

Dodge, P.P., F.D. Marks, J.F. Gamache, J.S. Griffin, and N.F. Griffin. EVTD radar analyses of the inner core of Hurricane Olivia (1994). Preprints, 27th Conference on Radar Meteorology, Vail, CO, October 9-13, 1995. American Meteorological Society, Boston, 299-301 (1995).

No abstract.

Dodge, P.P., F.D. Marks, J.F. Gamache, J.S. Griffin, and N.F. Griffin. The evolution of the inner core of Hurricane Olivia (1994) from EVTD Doppler radar analyses. Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 463-465 (1995).

No abstract.

Enfield, D.B., and J.E.Harris. A comparative study of tropical Pacific sea surface height variability: Tide gauges vs. the National Meteorological Center data-assimilating ocean general circulation model, 1982-1992. Journal of Geophysical Research, 100(C5):8661-8676 (1995).

To help assess the effectiveness of the model-based analysis and prediction procedures at the National Meteorological Center (NMC), we compare the seasonal and nonseasonal components of sea level from 44 tide gauges in the tropical Pacific with those of the dynamic heights output by two 11-year model reanalyses (1982-1992), at the same locations, which differ mainly in their wind forcing. Both reanalyses assimilate ocean thermal data and incorporate most of the procedures used by NMC in producing operational ocean analyses and experimental coupled model climate forecasts. The reanalyses reproduce the broad patterns of annual amplitude and phase, and of seasonal and nonseasonal variance, except for severe underestimates along the eastern boundary, especially north of the equator. The annual cycles and interannual departures of zonal flow indices estimated from selected island pairs near the dateline show good correspondence for the North Equatorial Countercurrent (NECC) and somewhat flawed and noisy comparisons for the North Equatorial Current (NEC) and South Equatorial Current (SEC). The reanalyses also reproduce the large scale time and space patterns of nonseasonal variability in the first three empirical orthogonal functions (EOFs), which together explain about 65% of the anomalous variability and characterize the El Niño/Southern Oscillation cycle. The first two EOF modes describe the westward migration of three ENSO episodes and the third mode appears to capture differences between episodes. However, the reanalysis based on the anomalous winds generated by the NMC medium range forecast model shows significant discrepancies in the large scale spatial and temporal variability. These discrepancies disappear in the reanalysis based on departures of the FSU analyzed wind fields. Hence, the wind forcing critically affects the reanalysis in spite of the assimilation of ocean thermal data. Future improvements in the atmospheric model to produce a more realistic evolution of the wind field can therefore lead to significantly better model integrations, in the analysis and initialization mode (with data assimilation) as well as in the coupled model forecast mode.

Feely, R.A., R.H. Wanninkhof, C. Cosca, H. Chen, M.D. Steckley, and P. Murphy. Distributions of fCO₂ in the eastern equatorial Pacific during and after the 1992-1993 El Niño: Global fluxes of carbon and its related substances in the coastal sea-ocean-atmosphere system. Proceedings, IGBP Symposium, Sapporo, Japan, November 1994. Hokkaido University, 360-367 (1995).

As part of the U.S. JGOFS Equatorial Pacific Process Study, measurements of fCO₂ were determined for the atmosphere and in the surface waters of the central and eastern equatorial Pacific during the spring and autumn of 1992 and 1993, and the spring of 1994 after the 1992-1993 ENSO event. Surface water fCO₂ data indicate significant differences between the springtime El Niño conditions and the autumn post-El Niño conditions. The autumn fugacity (DELTA fCO₂) maxima were approximately 15-55 µatm higher than in the spring. The lower surface DELTA fCO₂ values in the spring data set were the result of: (1) advection of CO₂-depleted water from the west at the equator near 170°W; and (2) reduced upwelling and lower DELTA fCO₂ distributions as consequence of lighter zonal winds in the eastern Pacific from 140°W to 110°W. In the spring of 1993 elevated sea surface temperatures were observed in spring of 1992. In spring 1994 sea surface temperatures were near the climatological mean and fCO₂ levels were 70-90 µatm higher than the 1992 levels. These results clearly indicate that the largest sustained fCO₂ variations in the eastern equatorial Pacific occur during ENSO events.

Feely, R.A., R.H. Wanninkhof, C.E. Cosca, P.P. Murphy, M.F. Lamb, and M.D. Steckley. CO₂ distributions in the equatorial Pacific during the 1991-1992 ENSO event. Deep-Sea Research, Part II, 42(2-3):365-386 (1995).

As part of the U.S. JGOFS Equatorial Pacific Process Study, measurements of CO₂ species concentrations were made in the atmosphere and in the surface waters of the central and eastern equatorial Pacific during the boreal spring and autumn of 1992. Surface water fCO₂ data indicate significant differences between the springtime El Niño conditions and the autumn post-El Niño conditions. The autumn fugacity (DELTA fCO₂) maxima were approximately 15-55 µatm higher than in the spring. The lower surface DELTA fCO₂ values in the spring data set were the result of: (i) advection of CO₂-depleted water from the west at the equator near 170°W; and (ii) reduced upwelling and lower DELTA fCO₂ distributions as a consequence of lighter zonal winds in the eastern Pacific from 140°W to 110°W. Assuming the springtime data are representative of the El Niño conditions and the autumn data are representative of the post-El Niño conditions, it is estimated that the net annual CO₂ flux during the 1991-1992 ENSO period is 0.3 Gt C. Over 60% of this flux occurred during the four-month period in the autumn when DELTA fCO₂ values were close to normal. The net annual reduction of the ocean-atmosphere CO₂ flux during the 1991-1992 El Niño is estimated to be on the order of 0.5-0.7 Gt C.

Feuer, S.E., and J. Kaplan. Tropical cyclone intensity change and environmental kinematic structure in Omega dropwindsonde data sets. Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 362-364 (1995).

No abstract.

Ffield, A., R.L. Molinari, W.D. Wilson, and R.H.Wanninkhof. Repeat hydrography along WHP lines 15°W, 17°N, and 11°W. International WOCE Newsletter, 20:23-24 (1995).

No abstract.

Finley, S.V., P.J. Fitzpatrick, J.A. Knaff, and C.W. Landsea. A systematic bias in the Aviation model's forecast of the Atlantic TUTT: Implications for tropical cyclone forecasting. Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 238-240 (1995).

No abstract.

Fitzpatrick, P.J., J.A. Knaff, C.W. Landsea, and S.V. Finley. A systematic bias in the Aviation model's forecast of the Atlantic tropical upper tropospheric trough: Implications for tropical cyclone forecasting. Weather and Forecasting, 10(2):433-446 (1995).

This study uncovers what appears to be a systematic bias in the National Meteorological Center's Aviation (AVN) model at 200 mb over the Caribbean Sea. In general, the 48 h forecast in the vicinity of the Tropical Upper Tropospheric Trough (TUTT) underpredicts the magnitude of the westerly 200-mb winds on the order of 5-10 m s^-1. This unrealistic weakening of the TUTT and associated cold lows by the AVN model results in erroneous values of the vertical (850-200 mb) wind shear. These systematic errors are in the same order of magnitude as the minimum shear threshold for tropical cyclone genesis and development. Thus, 48-h tropical cyclone formation and intensity forecasts based upon the AVN model are often incorrect in the vicinity of the TUTT. Knowing the correct future upper wind regime is also crucial for track forecasting of more intense tropical cyclones, especially in cases of recurvature. It is shown that simple persistence or climatology of the 200-mb winds south of a TUTT axis is superior to the AVN model's 48-h forecast. Until this bias in the AVN is successfully removed, the tropical cyclone forecaster for the Atlantic basin should be aware of this systematic error and make subjective changes in his/her forecasts. For 200-mb west winds greater than or equal to 10 m s^-1, forecasts based on persistence are best, while for west winds less than 10 m s^-1, half climatology and half persistence is the preferable predictor. If the TUTT is weak such that 200-mb easterly winds occur, climatology tends to be the best predictor as it nudges the forecast back to a normal westerly wind regime.

Franklin, J.L. Searching for beta gyres in Omega dropwindsonde data sets. Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 55-57 (1995).

No abstract.

Gamache, J.F. Preliminary three-dimensional analyses of dual-platform airborne Doppler observations of intense convection in eastern Pacific Hurricane Olivia (1994). Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 254-256 (1995).

No abstract.

Gamache, J.F., F.D. Marks, and F. Roux. Comparison of three airborne Doppler sampling techniques with airborne in-situ wind observations in Hurricane Gustav (1990). Journal of Atmospheric and Oceanic Technology, 12(1):171-181 (1995).

Three different airborne Doppler radar sampling strategies were tested in Hurricane Gustav (1990) on 29 August 1990. The two new strategies were the fore-aft scanning technique (FAST) and airborne dual-platform Doppler sampling. FAST employs radar scans in cones pointing alternately fore and aft of the vertical plane that is perpendicular to the flight track. The airborne dual-platform sampling uses two Doppler radars, each aboard a separate aircraft. The Doppler radars scan strictly in the vertical plane normal to the flight track. The aircraft fly simultaneously along different, preferably perpendicular, tracks. The third strategy tested in Hurricane Gustav was single-platform sampling, which uses one Doppler radar on one aircraft that flies two consecutive, usually orthogonal, flight tracks. The antenna scans in the plane normal to the flight track. The third technique had been used previously in hurricanes and other disturbed weather. The rms differences between the aircraft in-situ winds and the Doppler winds derived near the aircraft by single-platform sampling, dual-platform sampling, and FAST are found to be 7.8, 5.1, and 2.5 m sec^-1, respectively. These results suggest that in hurricanes dual-platform, flat-plane sampling and FAST both enable substantial improvements in the accuracy and temporal resolution of airborne Doppler wind fields over those obtained from single-platform, flat-plane scanning. The FAST results should be applicable to dual-beam sampling, which began in 1991. The actual rms errors of Doppler winds from the flight tracks, at levels well above flight level, and in highly sheared environments may be significantly higher than the above differences.

Garzoli, S.L., A. Gordon, and C. Duncombe Rae. Benguela Current sources and transports. U.S. WOCE Report, 17-19 (1995).

No abstract.

German, C.R., B.A. Barreiro, N.C. Higgs, T.A. Nelsen, E.M. Ludford, and M.R. Palmer. Seawater-metasomatism in hydrothermal sediments (Escanaba Trough, northeast Pacific). Chemical Geology, 119(1-4):175-190 (1995).

Hydrothermal sediments from the NESCA vent-field, Escanaba Trough, are enriched in a number of typical "vent-fluid" metals for which fluid data for the same, sediment-hosted, site exhibit anomalous depletion. These results are consistent with cooling of rising fluids and precipitation of various metal sulfide, sulfate, and oxide phases in-situ with the sediment column, prior to expulsion of the fluids from the seabed. Significant enrichments of Mg and U, elements which are quantitatively removed from high-temperature vent fluids, are also observed in the Escanaba Trough sediments, however. Enrichments of these elements cannot derive from simple conductive cooling of the rising vent-fluids but, instead, are believed to result from extensive seawater-metasomatism as relatively fresh unreacted seawater is heated from below by hot sediments and/or percolating vent-fluids in the upper levels of the circulation system. Calculated seawater/sediment interaction ratios range from -5:1 to 2500:1 of seawater per gram of sediment. Pb, Sr, and Nd isotope distributions for the Escanaba sediments are consistent with combined sediment-fluid and seawater-sediment interactions. Pb isotope ratios for hydrothermal and background sediments coincide with local sulfide deposits but are much more radiogenic than local MORB. This indicates not only that complete isotopic re-equilibration must occur between the hot, rising fluids and the host sediments but, in addition, that sediment composition appears to dominate the Pb isotopic composition of these fluids. Sr and Nd isotope ratios in the hydrothermally altered sediments, which are distinct from background ratios, coincide closely with modern seawater values, providing confirmatory evidence that extensive interactions must also have occurred between these hydrothermal sediments and relatively fresh, unreacted seawater.

Goldenberg, S.B., and L.J. Shapiro. A new look at the relationship between El Niño, west African rainfall, and North Atlantic tropical cyclone activity. Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 585-587 (1995).

No abstract.

Goni, G.J., G. Podesta, O.B. Brown, and J. Brown. Mesoscale ocean variability signal recovered from altimeter data in the southwest Atlantic Ocean: A comparison of orbit error correction in three GEOSAT data sets. Bolm Inst. Oceanogr., S. Paulo, 43(2):101-110 (1995).

Orbit error is one of the largest sources of uncertainty in studies of ocean dynamics using satellite altimeters. The sensitivity of GEOSAT mesoscale ocean variability estimates to altimeter orbit precision in the southwest Atlantic is analyzed using three GEOSAT data sets derived from different orbit estimation methods: (a) the original GDR data set, which has the lowest orbit precision; (b) the GEM-T2 set, constructed from a much more precise orbital model; and (c) the Sirkes-Wunsch data set, derived from additional spectral analysis of the GEM-T2 data set. Differences among the data sets are investigated for two tracks in dynamically dissimilar regimes of the southwestern Atlantic Ocean, by comparing (a) distinctive features of the average power density spectra of the sea height residuals, and (b) space-time diagrams of sea height residuals. The variability estimates produced by the three data sets are extremely similar in both regimes after removal of the time-dependent component of the orbit error using a quadratic fit. Our results indicate that altimeter orbit precision with appropriate processing plays only a minor role in studies of mesoscale ocean variability.

Gray, W.M., C.W. Landsea, P.W. Mielke, and K.K. Berry. Extended range forecast of the Atlantic seasonal hurricane activity for 1996. HKMetS Bulletin, 5(2):73-81 (1995).

This paper presents details of a 6-11 month extended range seasonal forecast of the tropical cyclone activity likely to occur in the Atlantic Ocean basin during 1996. This forecast is based on a forecast scheme developed previously by the authors with several new modifications. This allows estimates of seasonal Atlantic tropical cyclone activity to be made by late November of the prior year. Our ever-evolving forecast schemes are based on l0-month forward extrapolations of the stratospheric Quasi-Biennial Oscillation (QBO) of equatorial zonal winds, two measures of Western Sahel rainfall through late November 1995, an extended range forecast of El Niño conditions in August to October 1996, an extended range forecast of western Sahel rainfall amount for next summer, the November strength of the northeast Atlantic subtropical ridge, and other forecast parameters from the Pacific Ocean and from the Asia-Australia area. Information obtained through late-November 1995 indicates that 1996 Atlantic hurricane activity is likely to be somewhat below the 1950 to 1995 average with five hurricanes (average 5.7), eight named storms (average 9.3), 40 named storm days (average 46), 20 hurricane days (average 23), two intense (category 3-4-5) hurricanes (average 2.1), five intense hurricane days (average is 4.5) and a hurricane destruction potential (HDP) of 50 (average 68). Collectively, net tropical cyclone activity is expected to be 85% of the long period average. The 1996 season should be much less active than the 1995 season but somewhat more active than the four recent inactive hurricane seasons 1991 through 1994.

Gray, W.M., C.W. Landsea, P.W. Mielke, and K.K. Berry. Summary of the 1995 Atlantic tropical cyclone activity and verification of the authors' seasonal prediction. HKMetS Bulletin, 5(2):54-66 (1995).

This paper summarizes the tropical cyclone (TC) activity which occurred in the Atlantic Basin during 1995 and verifies the author's seasonal forecast of this activity which was initially issued on 30 November of last year, with updates on 5 June and 4 August of this year. The 1995 hurricane season was a year of near record hurricane activity. There was a total of 19 named storms (average 9.3) and 11 hurricanes (average 5.7) which persisted for a total of 62 days (average is 23). There were five major (intense) hurricanes of Saffir/Simpson category 3-4-5 (average is 2.1 intense hurricanes) with 11.5 intense storm days (average is 4.5). The seasonal total of named storm days was 121 or 262% of average and net tropical cyclone (NTC) activity was 237% of the average for the last 45 years. This unusually active hurricane season was the result of the concurrence of nearly all the physical factors known to enhance seasonal hurricane activity. This convergence of favorable factors typically occurs about once every 10-15 years. Of all these favorable factors, low values of surface pressure during 1995 were the most important. Our 1995 seasonal forecasts made on 30 November 1994, 5 June 1995, and 4 August 1995 all called for above average hurricane activity though not nearly as much hurricane activity as occurred.

Hansen, D.V., and H.F. Bezdek. Testing winds against other variables from COADS. Proceedings, International COADS Winds Workshop, Kiel, Germany, May 31-June 2, 1994. Institute for Meereskunde and Christian-Albrechts University, No. 265, 85-90 (1995).

No abstract.

Harvey, G.R. Petroleum hydrocarbon oxidation products in the marine atmosphere. Marine Pollution Bulletin, 30(6):425-426 (1995).

No abstract.

Hendee, J.C. Ocean Profiler: Software for the at-sea merging of oceanographic data. NOAA Technical Memorandum, ERL AOML-86 (PB96-128186), 18 pp. (1995).

Ocean Profiler is a computer program (software) that was constructed to meet the needs of oceanographers working at sea to build a master database of parameters as the data are generated. This report represents the technical manual for the operation of the software. Descriptions are provided for the loading, importing, and exporting of data files. Editing of data, adding of stations and fields to the database, deleting and cleaning up of data records, and replacing of certain values with others are features supported by the software. A Remote Bulletin Board System and an FTP site for downloading, a World-Wide Web location, and an e-mail address are provided for additional support for the software.

Hendee, J.C. Operations manual for PELAGOS: An expert system for quality control and feature recognition of oceanographic data from the open ocean. NOAA Technical Memorandum, ERL AOML-87 (PB96-131255), 68 pp. (1995).

An expert system was developed to aid oceanographers and data managers in the quality control and feature recognition of oceanographic data from the open ocean. Oceanographic data collected from the open ocean are screened for proper ranges against data collected from the same area during former cruises. Calculations are also performed on the data as a cross-check of certain parameters against others. The system developed runs on the PC, the Macintosh, and a UNIX workstation. The system is easily configurable to report only oceanographic parameters of interest. Data are read from, and output to, ASCII files. Source code is provided, and a list of avenues for further development is presented.

Houston, S.H., and M.D. Powell. Real-time surface wind analyses in support of marine warnings in tropical cyclones. Preprints, Second International Workshop on Wind and Earthquake Engineering for Offshore Coastal Facilities, Berkeley, CA, January 17-19, 1995. University of California at Berkeley, 323-328 (1995).

Real-time analyses of tropical cyclone wind observations are generated by the Hurricane Research Division (HRD) on an experimental basis. This paper describes analyses that apply to nearshore and offshore commercial activities affected by tropical cyclones. These products can help determine the extent of tropical storm and hurricane force winds for marine warnings. They can also be used as input to storm surge and wave models, as well as for estimating peak wind gusts associated with tropical cyclones.

Houston, S.H., W.A. Schaffer, M.D. Powell, and J. Chen. Comparisons of SLOSH parametric and HRD analyzed surface wind fields in recent hurricanes. Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 619-621 (1995).

In recent years, the Hurricane Research Division (HRD) has developed new techniques to analyze the surface wind fields in tropical cyclones based on all available surface wind observations, including aircraft flight-level observations adjusted to the surface. As part of NOAA's Coastal Ocean Program research on coastal hazards, the Techniques Development Laboratory (TDL) and HRD are evaluating wind fields used as input to the National Weather Service's (NWS) Sea, Lake, and Overland Surge from Hurricanes (SLOSH) model through comparisons with HRD's surface wind field analyses. The SLOSH model-computed water levels are used primarily by government and emergency management officials to plan for the evacuation of populations from coastal areas prone to flooding from storm surge produced by tropical cyclones. The model was developed for real-time forecasting of hurricane storm surges on continental shelves, across inland water bodies, and along coastlines. The values used to initiate the SLOSH model are each tropical cyclone's position, size, and intensity. Using these input parameters, a wind field is computed by SLOSH, which is used as the primary forcing mechanism for the oceanographic processes. Previously, the SLOSH model has been tested for hurricane landfalls along the U.S. coastlines and has been found to have an accuracy of ±20% when the hurricane is adequately described. Hurricane wind field cases examined in this study include Hugo (1989) at landfall in South Carolina, Bob (1991) at landfall in New England, Andrew (1992) at landfall in south Florida and Louisiana, as well as the closest approach of Bob (1991) and Emily (1993) to the North Carolina Outer Banks.

Jones, R.W., M. DeMaria, and C.R. Hagelberg. A comparison of data assimilation techniques in barotropic track forecasts of west Pacific typhoons. Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 141-142 (1995).

No abstract.

Kaplan, J. An examination of the role of large-scale forcing on the rapid intensification of Hurricane Emily (1987). Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 332-334 (1995).

No abstract.

Kaplan, J., and M. DeMaria. A simple empirical model for predicting the decay of tropical cyclone winds after landfall. Journal of Applied Meteorology, 34(11):2499-2512 (1995).

An empirical model for predicting the maximum wind of landfalling tropical cyclones is developed. The model is based upon the observation that the wind speed decay rate after landfall is proportional to the wind speed. Observations also indicate that the wind speed decays to a small, but nonzero, background wind speed. With these assumptions, the wind speed is determined from a simple two-parameter exponential decay model, which is a function of the wind speed at landfall and the time since landfall. A correction can also be added that accounts for differences between storms that move inland slowly and storms that move inland rapidly. The model parameters are determined from the National Hurricane Center best track intensities of all U.S. landfalling tropical cyclones south of 37°N for the period 1967-1993. Three storms that made landfall in Florida prior to 1967 were also included in the sample. Results show that the two parameter model explains 91% of the variance of the best track intensity changes. When the correction that accounts for variations in the distance inland is added, the model explains 93% of the variance. This model can be used for operational forecasting of the maximum winds of landfalling tropical cyclones. It can also be used to estimate the maximum inland penetration of hurricane force winds (or any wind speed threshold) for a given initial storm intensity. The maximum winds at an inland point will occur for a storm that moves inland perpendicular to the coastline. Under this assumption, the maximum wind at a fixed point becomes a function of the wind speed at landfall and the translational speed of motion. For planning purposes, maps of the maximum inland wind speed can be prepared for various initial storm intensities and speeds of motion. The model can also be applied to the entire wind field of an individual storm to provide a two-dimensional field of the maximum wind during a given storm. Examples of each of these applications are presented.

Katz, E.J., A. Busalacchi, M.H. Bushnell, F. Gonzalez, L. Gourdeau, M. McPhaden, and J. Picaut. A comparison of coincidental time series of the ocean surface height by satellite altimeter, mooring, and inverted echo sounder. Journal of Geophysical Research, 100(C12):25,101-25,108 (1995).

Altimetric measurements of sea surface height at two locations in the western tropical Pacific Ocean are compared to estimates of the dynamic sea surface height computed from cotemporal surface-to-bottom temperature/salinity measurements on moorings and acoustic travel time measured by bottom-moored inverted echo sounders. The results show statistically high correlation between the in-situ measurements at periods greater than five days and between the altimeter and in-situ measurements at periods greater than 20 days. The rms difference between any two modes of observation is consistently between 2-3 cm.

Keeling, R.F., and T.-H. Peng. Transport of heat, CO₂, and 0₂ by the Atlantic's thermohaline circulation. Philosophical Transactions of the Royal Society of London B, 348(1324):133-142 (1995).

We estimate transport of heat, CO₂, and O₂ by the Atlantic's thermohaline circulation using an approach based on differences in the chemical and physical characteristics of North Atlantic Deep Water (NADW), Antarctic Intermediate Water (AAIW), and the northward return flow across the equator. The characteristics of the return-flow waters are constrained by imposing conservation of phosphate in the North Atlantic as a whole. Based on a total equatorial return flow of 13 × 10⁶ m³ s^-1, we find that the Atlantic north of the equator is a source of 7.7 ± 1.4 × 10¹⁴ W to the atmosphere, a sink of 0.51 ± 0.21 × 10¹⁴ mol of O₂, and preindustrially was a sink of 0.33 ± 0.15 × 10¹⁴ mol of CO². Uptake of O₂ and CO₂ by the North Atlantic is driven mainly by thermal, as opposed to biological, processes.

Kim, Y., H. Sievering, J. Boatman, D. Wellman, and A.A.P. Pszenny. Aerosol size distribution and aerosol water content measurements during Atlantic Stratocumulus Transition Experiment/Marine Aerosol and Gas Exchange. Journal of Geophysical Research, 100(D11):23,027-23,038 (1995).

Aerosol size distribution data measured during the June 1992 Marine Aerosol and Gas Exchange experiment are analyzed to investigate the characteristics of fine marine aerosol particles measured over the North Atlantic near the Azores Islands. Measured aerosol size distribution data were corrected using the corrected size calibration data based on the optical properties of particles being measured. The corrected size distribution data were then approximated with either one or two lognormal size distributions, depending on air mass conditions. Under clean air mass conditions <3 µm diameter aerosol size distributions typically exhibited two modes, consisting of an accumulation mode and the small end of the sea-salt particle mode. However, under the influence of continental polluted air masses, the aerosol size distribution was dominated by <1 µm diameter particles in a single mode with an increased aerosol concentration. Aerosol water content of accumulation mode marine aerosols was estimated from differences between several series of ambient and dried aerosol size distributions. The average aerosol water fraction was 0.31, which is in good agreement with an empirical aerosol growth model estimate. The average rate of SO₄⁼ production in the accumulation mode aerosol water by H₂O₂ oxidation was estimated to be <7 × 10^-10 mol L^-1 s^-1, which is an insignificant contributor to the observed non-sea-salt SO₄⁼ in the accumulation mode.

Klein, B., R.L. Molinari, T.J. Muller, and G. Seidler. A transatlantic section at 14.5°N: Meridional volume and heat fluxes. Journal of Marine Research, 53:929-957 (1995).

Two high-resolution hydrographic sections occupied during February and March 1989 in the western and eastern basins of the North Atlantic at 14.5°N are combined to study the water mass structure and meridional mass and heat transports. Absolute velocities were determined using these data and an earlier section at 8°N in a linear inverse analysis. Mass balance for several layers representing the main water masses in the region and a zero net divergence for the sum of geostrophic and Ekman transport between the two sections are assumed. Using the annual mean of Ekman transports (13.6 Sv, 14.5°N), (15.2 Sv, 8°N) based on the climatology by Isemer and Hasse (1985), the annual average fluxes for the sections at 8°N and 14.5°N have been calculated. For the annual mean the strength of the meridional overturning cell at 14.5°N amounts to 15.9 Sv with an associated heat transport of 1.22 PW. A similar value can be obtained at 8°N where the annual mean heat transport reaches 1.18 PW and the overturning cell measures 15 Sv. The total northward heat transport is strongly dominated by the wind-driven Ekman heat transport. In-situ values of heat transport using the actual wind-driven transports for the respective months yield even higher estimates. Heat transport at 14.5°N rises to 1.37 × 0.42 PW (February) and the maximum is now at the 8°N section, 1.69 × 0.52 PW (May). Comparisons of our results with another tropical section at 11°N occupied concurrently demonstrate the large variabiltiy in heat transport related to changes in the wind field. Due to extremely weak winds in the eastern Atlantic and a resulting low Ekman transport, the in-situ value of heat transport through this section ranged between 0.30 × 0.18 PW and 0.59 × 0.18 PW depending on the value chosen for the Ekman transport. The lower of the two heat transport estimates results from calculations with the acutal observed winds and the other using a monthly climatological mean. That even the computations with the climatological monthly mean give such a low heat transport points to additional changes in the baroclinic structures between 11°N and 14.5°N.

Lamb, M.F., T.P. Lantry, J.C. Hendee, K.E. McTaggart, P.P. Murphy, R.A. Feely, R.H. Wanninkhof, F.J. Millero, R.H. Byrne, E.T. Peltzer, and D. Frazel. Chemical and hydrographic measurements from the equatorial Pacific during boreal autumn 1992. NOAA Data Report, ERL PMEL-56 (PB95-274809), 173 pp. (1995).

In the boreal autumn of 1992, NOAA's Climate and Global Change Program sponsored a major cooperative effort with the U.S. JGOFS Program in the central and eastern equatorial Pacific to investigate the unique role of equatorial processes on CO₂ cycling during and following the 1991-1992 ENSO event. Data were collected meridionally along four transects, generally between 10°N and 10°S. The first leg (Leg 3) included the 140°W and 125°W transects; the second leg (Leg 4) sampled along 110°W, and the third leg (Leg 5) included stations along 95°W and three short transects extending westward from the Peru coast. Chemical parameters sampled included fCO₂, DIC, TAlk, pH, TOC, and nutrients. Ancillary measurements of salinity, temperature, and dissolved oxygen (DO) were also taken. Descriptions of sampling methods and data summaries are given in this report.

Landsea, C.W. SHIFOR94: Atlantic tropical cyclone intensity forecasting. Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 365-367 (1995).

No abstract.

Landsea, C.W., W.M. Gray, P.W. Mielke, and K.J. Berry. June to September rainfall in the African Sahel: Verification of our 1995 forecasts and an extended range forecast for 1996. HKMetS Bulletin, 5(2):66-70 (1995).

No abstract.

Lantry, T.P., M.F. Lamb, J.C. Hendee, R.H. Wanninkhof, R.A. Feely, F.J. Millero, R. Byrne, E.T. Peltzer, W.D. Wilson, and G.A. Berberian. Chemical and hydrographic measurements from the equatorial Pacific during boreal spring 1992. NOAA Data Report, ERL AOML-27 (PB95-227773), 134 pp. (1995).

From February 24 to May 19, 1992, the National Oceanic and Atmospheric Administration's (NOAA) Climate and Global Change Program sponsored a major cooperative effort with the U.S. Joint Global Ocean Flux Study (U.S. JGOFS) to study the role of equatorial processes on CO₂ cycling in the central and eastern equatorial Pacific during the 1991-1992 El Niño Southern Oscillation (ENSO) event. The NOAA Ship Malcolm Baldrige performed four transequatorial sections in the region and this report presents hydrographic and chemical data from that cruise, including tables of the following data from each station: hydrography from each CTD cast at the bottle trip depths, dissolved oxygen, fCO₂, DIC, pH, TAlk, nutrients, and TOC. Descriptions of the sampling techniques and analytical methods used in the collection and processing of these data are also presented.

Lowell, R.P., P.A. Rona, and R.P. Von Herzen. Seafloor hydrothermal systems. Journal of Geophysical Research, 100(B1):327-352 (1995).

The discovery of seafloor hydrothermal systems approximately two decades ago has led to a major reassessment of the Earth's thermal and geochemical budgets and has revolutionized our understanding of biological processes. This review traces the development of the study of seafloor hydrothermal systems from the indirect evidence provided by conductive heat flow anomalies to the discovery of approximately equal to 350�C black smoker vents on the East Pacific Rise at 21�N. Although the review focuses on physical characteristics and processes, it outlines some key characteristics of vent fluid chemistry that provide constraints on physical models. Ridge crest systems have thermal power outputs ranging from 10 to 10⁴ MW. They are transient systems, driven by magmatic heat sources, but episodie events such as megaplumes, the interplay between focused and diffuse venting, and other aspects related to their thermal, chemical, and biological evolution remain poorly understood. Advances will be made by continuing exploration and discovery to determine the full range of possible phenomena both on and off axis and in different tectonic settings. In order to understand the complete, integrated ridge system, however, future studies must include long-term monitoring of an active system, deep drilling into the reaction zone, and mathematical modeling that incorporates both physical and chemical constraints.

MacIntyre, S., R.H. Wanninkhof, and J.P. Chanton. Trace gas exchange across the air-water interface in fresh water and coastal marine environments. In Biogenic Trace Gases: Measuring Emissions from Soil and Water, P.A. Matson and R.C. Harriss (eds.). Blackwell Science, Cambridge, 52-97 (1995).

No abstract.

Mayer, D.A., J.F. Festa, R.L. Molinari, and D.W. Behringer. Model and observed upper layer temperature structure of the gyres of the Atlantic Ocean. Proceedings, ACCP Principal Investigators Meeting, Miami, Florida, May 2-4, 1995. University Corporation for Atmospheric Research, 205 pp. (1995).

No abstract.

McAdie, C.J., P.P. Dodge, and S.H. Houston. Mesoscale features of Tropical Storm Beryl (15-16 August 1994) as detected by the WSR-88D. Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 320-322 (1995).

No abstract.

Millero, F.J., W. Yao, K. Lee, J.-Z. Zhang, and D.M. Campbell. The carbonate system near the Galapagos Islands. University of Miami Technical Report, RSMAS-95-001, 104 pp. (1995).

During the IRONEX cruise and theh PlumEX experiments around the Galapagos Islands, measurements were made on the components of the carbonate system. The carbonate parameters pH, TA (total alkalinity), TCO₂ (total carbon dioxide), and fCO₂ (fucacity of CO₂) were determined. The pH measurements (± 0.002) were made using spectrophotometric techniques, the TA (± 2 µmol kg^-1) measurements were made by potentiometric titrations, the TCO₂ (± 2 µmol kg^-1) were determined by coulometry and the fCO₂ in the surface waters (± 2 µatm) was determined using an infrared detector. A significant decrease of the surface TCO₂ (7 µmol kg^-1) and fCO₂ (11 µatm) in the Fe patch was detected within 48 hours of the iron release. This decrease, however, did not continue. A good correlation was found between TCO₂, pH, and fCO₂ with temperature in the surface waters around the Galapagos Islands. The effect of high primary production on the CO₂ system in the downstream plume is overshadowed by the upwelling waters with high CO₂.

Millero, F.J., J.-Z. Zhang, K. Lee, J. Aicher, S. Mane, S. Olivella, D.O. Medina, and P.A. Steinberg. Ph and total alkalinity measurements in the North Atlantic. University of Miami Technical Report, RSMAS-95-004, 81 pp. (1995).

This report gives the results of our pH (spectrophotometry and potentiometry), total alkalinity (TA), and total inorganic carbon dioxide (TCO₂) measurements made in the North Atlantic during the Joint Global Ocean Flux Study (JGOFS) sponsored by the National Oceanic and Atmospheric Administration (NOAA). Measurements of TA on 91 samples of Certified Reference Materials (CRMs) with the three cells at sea indicate that the systems have a reproducibility of ± 3 µmol/kg in TA. The resulting pH, TA, and TCO₂ are thought to be precise to ± 0.002 (spectrophotometry) and ± 0.01 (potentiometry) in pH, ± 3 µmol kg^-1 in TCO₂, and ± 3 µmol kg^-1 in TA. Our titration results will be combined with NOAA measurements of TCO₂ (coulometry) and fCO₂ to characterize the CO₂ system in the North Atlantic.

Montgomery, M.T., and L.J. Shapiro. Generalized Charney-Stern and Fjortof theorems for rapidly rotating vortices. Journal of the Atmospheric Sciences, 52(10):1829-1833 (1995).

A generalized Charney-Stern theorem for rapidly rotating (large Rossby number) baroclinic vortices, such as hurricanes, is derived based on the asymmetric balance (AB) approximation. In the absence of dissipative processes, a symmetrically stable baroclinic vortex is shown to be exponentially stable to nonaxisymmetric perturbations if a generalized potential vorticity gradient on theta surfaces remains single signed throughout the vortex. The generalized potential vorticity gradient involves the sum of an interior potential vorticity gradient associated with the symmetric vortex and surface contributions associated with the vertical shear of the tangential wind. The AB stability formulation is then shown to yield Fjortof's theorem as a corollary. In the modern view of shear instabilities the theorems admit simple interpretation. The Charney-Sterm theorem represents a necessary condition for the existence of counterpropagating Rossby waves associated with the radial potential vorticity gradient, while Fjortof's theorem represents a necessary condition for these waves to phase lock and grow in strength. Potential application of these results as well as limitations of the slow-manifold approach are briefly discussed.

Nelsen, T.A., P. Blackwelder, T. Hood, C. Zarikian, J.H. Trefry, S. Metz, B. Eadie, and B. McKee. Retrospective analysis of NECOP area sediments: Biogenic, inorganic and organic indicators of anthrogenic influences since the turn of the century. Proceedings, 1994 Synthesis Workshop, Baton Rouge, LA, April 26-28, 1994. Louisiana Sea Grant Program, 90-101 (1995).

Surface and cored sediments from the NECOP study area were analyzed for physical (coarse-grain texture, composition), biological (foraminifera), and chemical (organic and inorganic) properties. Results of analyses for surface samples indicated spatial patterns of benthic foraminifera dictated by sediment accumulation rate and regions of seasonal hypoxia. The latter also correlated well with the distribution of surface authigenic glauconite. Temporal variability, determined from core samples, indicated transitions in benthic foraminifera community structure with upcore increases in hypoxia tolerant assemblages. Transitions in glauconite abundance, organic carbon, and other chemical parameters strongly correlated temporally with increases in fertilizer application in the United States.

Niiler, P.P., A.S. Sybrandy, K. Bi, P.M. Poulain, and D.S. Bitterman. Measurements of the water-following capability of holey-sock and TRISTARdrifters. Deep-Sea Research, Part I, 42(11/12):1951-1964 (1995).

Since 1985, a number of measurements have been made in deep water to determine the water-following characteristics of mixed layer drifters with both holey-sock and TRISTAR drogues at 15 m depth. The measurements were done by attaching two neutrally buoyant vector measuring current meters (VMCMs) to the top and the bottom of the drogues and deploying the drifters in different wind and upper ocean shear conditions for periods of 2-4 h. The average velocity of the VMCM records was taken to be a quantitative measure of the slip of the drogue through the water, observed to be 0.5-3.5 cm s^-1. The most important hydrodynamic design parameter which influenced the slip of the drogue was the ratio of the drag area of the drogue to the sum of the drag areas of the tether and surface floats: the drag area ratio R. The most important environmental parameters which affected the slip were the wind and the measured velocity difference across the vertical extent of the drogue. A model of the vector slip as a function of R, vector wind and velocity difference across the drogue was developed and a least squares fit accounts for 85% of the variance of the slip measurements. These measurements indicated that to reduce the wind produced slip below 1 cm s^-1 in 10 m s^-1 wind speed, R > 40. Conversely, if the daily average wind is known to 5 m s^-1 accuracy, the displacement of the R = 40 drifter can be corrected to an accuracy of 0.5 km day^-1.

Ooyama, K.V. A thermodynamic foundation for modeling the moist atmosphere. Part II: Tests of microphysics in the formation of squall lines. Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 219-221 (1995).

No abstract.

Ortner, P.B., and M.J. Dagg. Nutrient-enhanced coastal ocean productivity in the Gulf of Mexico. EOS, Transactions, American Geophysical Union, 76(10):97, 109 (1995).

No abstract.

Ortner, P.B., T.N. Lee, P.J. Milne, R.G. Zika, M.E. Clarke, G.P. Podesta, P.K. Swart, P.A. Tester, L.P. Atkinson, and W.R. Johnson. Mississippi River flood waters that reached the Gulf Stream. Journal of Geophysical Research, 100(C7):13,595-13,601 (1995).

Distributions of physical, biological, and chemical parameters in Florida Keys coastal waters seaward of the reef track were surveyed on September 9-13, 1993, as part of a coordinated multi-disciplinary study of surface transport processes. A band of low-salinity water was observed along the shoreward side of the Florida Current over the downstream extent of the survey from Miami to Key West. Biological and chemical indicators within the band, together with its large volume, satellite imagery, and a surface drifter trajectory suggested the recent Mississippi River flood as the source.

Palmer, D.R. Acoustic imaging of underwater plumes. Acoustical Imaging, 21:241-255 (1995).

We review the research that has been done to acoustically image naturally occurring underwater plumes. Since our interest is in the use of acoustical techniques to study fluxes of material and heat across the ocean-seafloor interface, the review is limited to studies of those plumes that result from vents located on the seafloor. The review was undertaken to gain perspectives that might help in our efforts to image black-smoker hydrothermal plumes in the deep ocean. Specifically, we wanted to identify common themes in hardware development, experimental design, and data analysis and interpretation. After describing the general structure of an underwater plume and discussing the advantages of sonar imaging, we survey the individual experimental efforts. These include observations of offshore and deep-ocean hydrocarbon plumes, buoyant plumes from a submarine spring, and buoyant and neutrally-buoyant hydrothermal plumes. We then make some general statements about the characteristics of imaging sonars and their platforms, sonar calibration, scattering mechanisms, and the potential for Doppler measurements. Finally, we discuss the importance of in-situ observations. We argue that acoustical imaging can complement but cannot replace in situ measurements. In fact, it is not extreme to adopt the point of view that the primary purpose of acoustical imaging of underwater plumes is to support the collection of in-situ data.

Pasteur, E.C., R. Mulvaney, D.A. Peel, E.S. Saltzman, and P.-Y. Whung. A 340 year record of biogenic sulphur from the Weddell Sea area, Antarctica. Annals of Glaciology, 21:169-174 (1995).

Detailed records of methanesulphonic acid (MSA) and non-sea-salt sulphate (nss SO₄^2-) have been obtained from ice cores drilled on Dolleman Island on the east coast of the Antarctic Peninsula (70°35.2'S, 60°55.5'W). Annual average concentrations of MSA are presented for the period 1652-1992. Over this time span, the mean annual concentration of MSA is 0.69 µ = l^-1 (sigma = 0.33, n = 340), the range is 0.13-2.35 µ = l^-1, and the MSA/nss-SO₄^2- ratio is 0.22. The high MSA concentration reflects the proximity of the Weddell Sea, believed to be a region of high marine phytoplankton production. The overall mean nss-SO₄^2- concentration is about 66% of the total sulphate deposited in the snowfall. Low-frequency variations of MSA and oxygen-isotope signals correlate closely, indicating that they may be modulated by similar atmospheric processes. Positive correlations are observed between the oxygen-isotope signature and both MSA (r = 0.41) and nss-SO₄^2- (r = 0.50), significant at the 99% level. A small negative correlation can be seen between both species and the annual duration of sea ice at Scotia Bay, Laurie Island in the South Orkneys, since 1902 (MSA r = 0.23, and nss-SO₄^2- r = 0.29; significant at 95% confidence). No significant link between high MSA concentrations and El Ni�o events is observed at this location.

Peng, T.-H. Future climate surprises. In Future Climates of the World: A Modeling Perspective, A. Henderson-Sellers (ed.). Elsevier Science, Amsterdam, 517-535 (1995).

No abstract

Peng, T.-H., and W.S. Broecker. Estimate of interhemispheric ocean carbon transport based on CO₂ and nutrient distribution. In Ecological Time Series, T.M. Powell and J.H. Steele (eds.). Chapman and Hall, New York, 28-47 (1995).

No abstract.

Picaut, J., A.J. Busalacchi, M.J. McPhaden, E.J. Katz, L. Gourdeau, F.I. Gonzalez, E.C. Hackert, and M.H. Bushnell. Open-ocean validation of TOPEX/POSEIDON sea level in the western equatorial Pacific. ORSTOM Report No. 5, 76 pp. (1995).

During the verification phase of the TOPEX/POSEIDON radar altimeter mission a rigorous open-ocean validation experiment was conducted in the western equatorial Pacific Ocean. From August-September 1992 to February-March 1993 two TOGA-TAO moorings at 2°S-156°E (1739 m depth) and 2°S-164.4°E (4400 m depth) were outfitted with additional temperature, salinity, and pressure sensors to measure precisely the dynamic height from the surface to the bottom at 5-min intervals directly beneath two TOPEX/POSEIDON crossovers. Bottom pressure gauges and inverted echo sounders were deployed as well. A pre-deployment design study using full depth CTD casts, subsequently confirmed by post-deployment analyses, indicated this suite of instruments was capable of measuring sea surface height fluctuations to within 1-2 cm. The validation experiment also benefited from the comprehensive set of ocean-atmosphere measurements that were made in the region during the TOGA-COARE intensive observation period of November 1992-February 1993. The surface relative to bottom dynamic height fluctuations observed in-situ during the 6-7 month experiment had a standard deviation of 5 cm with excursions of order �15 cm. Energetic steric sea level variability was found to exist on short time scales of order hours to a few days, most notably the quasi-permanence of strong semi-diurnal internal tides. Such internal tides were noted to induce changes in surface dynamic height with a standard deviation of 2 dyn cm. At the shallower of the two sites, 2°S-156°E, a possible nonlinear rectification of the internal tide was observed occasionally to change the dynamic height by as much as 30 cm over less than an hour. On time scales longer than the 10 day repeat of the TOPEX/POSEIDON satellite, the low-frequency fluctuations of dynamic height were related to interannual variations corresponding to the 1991-1993 ENSO, to the seasonal cycle and to intraseasonal variations associated with the 40-60 day oscillations of the equatorial zonal wind field. Instantaneous comparisons between the 1 sec TOPEX/POSEIDON altimeter retrievals and the 5-min dynamic height were performed with regard to several tide models, the barotropic tide measured in-situ, ECMWF surface air pressure, and the surface air pressure measured in-situ. Depending on the choice of altimeter and of the environmental corrections applied to the altimeter data, the rms differences between the satellite and the in-situ measurements of sea level were as low as 3.3 cm at 2°S-156°E and 3.7 cm at 2°S-164.4°E. When additional satellite data in the general vicinity of the mooring are included, and after the use of a 30-day low-pass filter, the satellite and in-situ data were found to be highly correlated, with correlation coefficients of about 0.95 and rms differences around 1.8 cm.

Powell, M.D., S.H. Houston, and I. Ares. Real-time damage assessment in hurricanes. Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 500-502 (1995).

No abstract.

Proni, J.R. Acoustical studies of sewage and dredged discharges. Proceedings, Second International Conference on the Mediterranean Coastal Environment (MEDCOAST 95), Tarragona, Spain, October 24-27, 1995. International Center for Coastal and Ocean Policy Studies, 14 pp. (1995).

Through the use of advanced acoustical technology, significant improvements in monitoring anthropogenic discharges in coastal waters can be obtained. In particular, acoustical systems may be used to accurately define the water volume occupied by sewage effluent and dredged material discharges as a function of three dimensional space and time. With such accurate definitions of the location and distribution of wastes, accurate, acoustically-guided, chemical, and biological sampling can be carried out. In combination with other technologies, design optimization and discharge procedure optimization can be addressed through the use of research results and realtime monitoring, respectively. Two case studies will be discussed: the first will be a study of four wastewater outfalls discharging in the near coastal water and the second will be dredged material discharged in near coastal waters.

Proni, J.R., J.J. Tsai, and J.F. Craynock. Acoustic profiling of disposed dredge material in the 6-mile MUD dumpsite, New York. Contract Report, 68-C8-0105, U.S. Environmental Protection Agency, 17 pp. (1995).

No abstract.

Prospero, J.M., and P.B. Ortner, Co-covenors. Report: South Florida Coastal Ocean Ecosystem Workshop, Miami, FL, February 27-28, 1995. University of Miami, Cooperative Institute for Marine and Atmospheric Studies, 2 volumes, 164 pp. (1995).

The South Florida Coastal Ocean Ecosystem (SoFCOE) encompasses Florida Bay, the coral reefs of the Florida Keys, and the ocean margins of the unique Everglades ecosystem. All these regions are interconnected; they are also closely linked to, and affected by, the waters of the Straits of Florida, the Gulf of Mexico, and the Caribbean Sea through the effects of various current systems. Over the past few decades, the SoFCOE has undergone great changes due to altered freshwater flow through South Florida, sharply increased human population in South Florida, including the Florida Keys, and intensified sports and commercial fishing. These changes have resulted in extensive degradation in many locations. Continued rapid growth in the region could greatly exacerbate these stresses. Major efforts have been initiated to protect and restore these environments and, as a result, the SoFCOE is emerging as a key study area for improving methods and principles of management and protection of regional coastal resources that are of national interest.

Pujals, G., C. Bakker, M.D. Powell, and S.H. Houston. Demonstration of object-oriented software for real-time acquisition and presentation of meteorological fields in hurricanes. Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 303-305 (1995).

No abstract.

Samsury, C.E., and E.J. Zipser. Secondary wind maxima in hurricanes: Air-flow and relationship to rainbands. Monthly Weather Review, 123(12):3502-3517 (1995).

Aircraft flight-level data from 787 radial legs in 20 hurricanes are analyzed to identify the composite kinematic structure in the hurricane eyewall, and especially with secondary horizontal wind maxima (SHWM) that occur outside the eyewall. Similar to previous studies, analysis of the flight-level wind data in the eyewall reveals radial convergence near the radius of maximum wind (RMW), and the highest frequency of updrafts and the largest upward mass transport radially inward of the RMW. More than 20% of the flight legs contain substantial secondary horizontal wind maxima of specified strength and length. The kinematic structure associated with SHWM is similar to that of the hurricane eyewall with radial convergence near the radius of maximum wind and a preferred location for maximum upward motions and upward mass transport just inside the RMW. Statistical analysis confirms the similarity in characteristics between radial and vertical velocities of the eyewall and near the SHWM. In addition, for both the eyewalls and the SHWM, the radial velocity composite results show that the radial mass transport in the planetary boundary layer must be largely confined to the lowest 1000 m. Lower fuselage radar reflectivity data from 13 of the hurricanes are used to assess whether the outer wind maxima are associated with rainbands, and vice versa. In the radial legs with SHWM for which radar data were available, the secondary horizontal wind maximum was frequently associated with a mesoscale reflectivity feature (rainband). In contrast, many rainbands, more than 70%, were without wind maxima. The results from this study show that to some extent an outer eyewall or rainband with SHWM can act as a barrier to inflow to the inner wall. Additionally, it is possible that thermodynamic modification of inflow air may occur as a result of convective-scale vertical motions associated with a rainband. In those cases when an outer rainband encircles the eyewall, it is possible that these factors act together with subsidence to weaken the inner eyewall.

Samsury, C.E., M.L. Black, and R.E. Orville. The relationship of cloud-to-ground lightning with radar reflectivity and vertical velocity in Hurricanes Bob (1991) and Emily (1993). Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 257-259 (1995).

No abstract.

Schmid, C., H. Schafer, G. Podesta, and W. Zenk. The Vitoria eddy and its relation to the Brazil Current. Journal of Physical Oceanography, 25(11):2532-2546 (1995).

In late austral summer 1991, a cyclonic thermocline eddy was detected in the subtropical western South Atlantic off the Brazilian shelf near the city of Vit�ria. This Vit�ria eddy was tracked for 55 days by surface drifters drogued at 100 m depth. The drifters had been deployed in the western boundary current regime by FS Meteor as part of a basin-wide surface current study. The analysis of a combined CTD/XBT section across the Vit�ria eddy, together with drifter data and satellite images of the thermal surface structure, revealed the unexpected complexity of the region. The eddy interacted not only with the local topography and the Brazil Current, located further offshore, but also with an extended upwelling regime north of Cabo Frio. The hydrographic and kinematic properties and anomalies of the Vitoria eddy are analyzed and compared with similar vortices described elsewhere in the literature.

Serafy, J.E., S. Lutz, T.R. Capo, P.B. Ortner, and P. Lutz. Anchor tags affect swimming performance and growth of juvenile red drum (Sciaenops ocellatus). Marine and Freshwater Behavior and Physiology, 27(1):29-35 (1995).

Swimming efficiency and growth of anchor-tagged red drum (Sciaenops ocellatus) juveniles were compared with untagged controls. The O₂ consumption of fish swimming at different speeds was measured in a Blaska-type respirometer. Daily growth rates of tagged and untagged red drum were compared over 42 days of feeding fixed rations of live mosquitofish (Gambusia affinis) to siblings held individually in 380 L tanks. At swimming speeds of <1.0 body lengths per second (bl s^-1), no differences in O₂ consumption were found. However, at speeds of 1.5-2.5 bl s^-1, tagged red drum O₂ consumption was significantly greater (by 36-39%) than that of untagged fish (anova, P <0.05), indicating a substantially impaired swimming efficiency. Daily growth rates of tagged an untagged fish also differed significantly (P < 0.02). Tagged fish grew at a mean rate of 0.95 mm d^-1, and 1.45 g d^-1, while untagged fish (controls) grew at 1.14 mm d^-1 and 1.62 g d^-1. Results suggest that internal anchor tags, which weighed less than 1% of fish body weight, represented a hydrodynamic drag burden that reduced swimming performance and growth. These effects may decrease growth and/or survival in the wild and thus bias estimates of biological parameters in stock assessment and enhancement studies.

Shapiro, L.J., and J.L. Franklin. Potential vorticity in Hurricane Gloria. Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 524-525 (1995).

No abstract.

Shapiro, L.J., and J.L. Franklin. Potential vorticity in Hurricane Gloria. Monthly Weather Review, 123(5):1465-1475 (1995).

Potential vorticity (PV) analyses for Hurricane Gloria of 1985 are derived from nested objective wind analyses of Omega dropwindsonde and airborne Doppler radar data. The analyses resolve eyewall-scale features in the inner vortex core and embed analyses of these features within the larger-scale environment. Since three-dimensional geopotential height fields required for evaluation of PV are not available in the core, they are derived using the balance equation. In the process of deriving the heights, the degree of gradient balance is evaluated. The 500-mb tangential winds in the core, averaged azimuthally on the four cardinal points, are close to gradient balance outside the radius of maximum wind. The resulting depiction of PV is the first presented for a real hurricane. Due to data deficiencies immediately outside the Doppler region, as well as inside the eye, smoothing of the wind data using a filter with a minimum 25-km spatial scale is required to derive a balanced geopotential height distribution consistent with a statically stable vortex. The large-scale PV distribution evidences asymmetries in the middle and upper troposphere that appear to be associated with Gloria's translation to the northwest. Eyewall-scale PV in the core, and PV of the azimuthally-averaged vortex, are also presented.

Sievering H., E. Gorman, T. Ley, A.A.P. Pszenny, M. Springer-Young, J. Boatman, Y. Kim, C. Nagamoto, and D. Wellman. Ozone oxidation of sulfur in sea-salt aerosol particles during the Azores Marine Aerosol and Gas Exchange experiment. Journal of Geophysical Research, 100(D11):23,075-23,082 (1995).

Sea-salt aerosol particles in the lowest tens of meters above the ocean are, typically, more than three-fourths water on a volume basis. Calculations herein indicate that aqueous-phase conversion of sulfur dioxide dissolved in the water associated with sea-salt particles (sea-salt aerosol water) support the production of 2-8 nmol m^-3 of nonsea-salt sulfate (nssSO₄⁼) during the Marine Aerosol and Gas Exchange (MAGE) experiment intensives. This production is based on ozone oxidation of dissolved SO₂ in sea-salt aerosol water and accounts for sulfur gas and ozone mass transfer limitations as a function of sea-salt particle size. Measurements show that 1-15 nmol m^-3 of nssSO₄⁼ was actually present in the sea-salt particle mode except for four enhanced concentration cases due to continental sulfur input. The range in predicted as well as observed nssSO₄⁼ produced by ozone oxidation of sulfur dioxide, being in the sea-salt particle mode with observed volume geometric median diameter of 3.5-5 µm, is dry, deposited at a fairly rapid rate. The remainder, being large-particle cloud condensation nuclei, may contribute little to cloud albedo over the global oceans. The two papers following this one, Kim et al. (this issue) on aerosol size distribution and water content and Parfai et al. (this issue) on compositional variations of sea-salt-mode aerosol particles observed by electron microscopy, complement and support results presented here. All three present results of the MAGE experiment and precede a forthcoming special of the Journal of Geophysical Research-Atmospheres on MAGE (B. Huebert, guest editor).

Thacker, W.C. Statistical modeling for numerical modelers. GKSS-Forschungszentrum,7-80 (1995).

This report contains the material that formed the basis for a series of lectures presented at the GKSS Research Center during the summer of 1994. The audience consisted primarily of meteorologists and oceanographers who were familiar with numerical modeling typical of numerical weather prediction, and the intent of the lectures was to provide an overview of ideas and techniques of statistical modeling within the context of predicting the seasonal-to-interannual climate. Because of the large numbers of variables needed to characterize climatic fields and the opposing requirement that statistical models have a relatively small number of predictors, emphasis is placed on the use of indices constructed as linear combinations of field variables as predictors.

Tsai, J.J., H. Huang, and J.R. Proni. Acoustic observations of bottom surge from dredged material discharge in the open ocean. Chemistry and Ecology, 10(1-2):71-85 (1995).

Bottom surges generated from dredged material discharges in the open ocean have been observed using high frequency acoustic concentration profilers in several field studies during the past five years. The locations, water depths, bottom slopes, oceanographic conditions, and the dredged material composition differed from study to study. Observed surges at three dredged material disposal sites may develop more than one surge peak for a single discharge. For water depths of the order of 10 m, surge height of the leading peak was estimated to be about one quarter of the water depth. For water of greater depth, of the order of 100 m, surge height reached 70 m, about 70% of the water depth. Surge height is established instantaneously when dredged material hits the bottom, and remains relatively constant as the surge advances horizontally. Total surge length reached 150 m for water depths of 10 m when measured from the impact point to the leading edge. For water depths of more than 100 m, the surge length reached more than 100 m. Length of the leading surge peak was as large as 45 m at this water depth. Dimensional analysis was applied to relate the surge height of the leading surge peak to discharge parameters and oceanographic conditions. Results showed that the ratio of surge height to water depth was proportional to 1/10 power of the ratio of discharge volume to the third power of water depth.

Vaughan, S.L., and K.D. Leaman. The role of small-scale cells in the Mediterranean convection process. Journal of Physical Oceanography, 25(10):2423-2436 (1995).

Data from the Gulf of Lions in the northwest Mediterranean in 1987 indicated that the deep convection known to occur in that region was organized into small-scale [O(1 km)] cells embedded in a larger-scale [0(50 km)] homogeneous "patch." Velocities from current meters showed that during the period of strong surface forcing a front of increased kinetic energy propagated downward, finally reaching the bottom. An analytic expression for the depth of penetration of this front as a function of time and surface buoyancy flux was derived, using a simple one-dimensional model of the density profile, which agreed well with the observations. An analytic expression for the kinetic energy density was derived as a function of time, dissipation rate, and rate of change of potential energy, assuming conservation of total energy. Estimates of not volume transport were made from frequency distributions of vertical velocity. Results indicate that the cells provided the turbulence necessary to efficiently mix the water column vertically, removing the existing weak but stable stratification. The cells were not directly responsible for any net volume transport downward but did contribute to the transport of fluid properties such as heat, energy, and chemical tracer concentration.

Wanninkhof, R.H., R.A. Feely, D.K. Atwood, G.A. Berberian, W.D. Wilson, P.P. Murphy, and M.F. Lamb. Seasonal and lateral variations in carbon chemistry of surface water in the eastern equatorial Pacific during 1992. Deep-Sea Research, Part II, 42(2-3):387-409 (1995).

During the (boreal) spring and fall of 1992, the NOAA Ocean-Atmosphere Carbon Exchange Study did an intensive survey of upper water column (<1000 m) chemistry in the eastern equatorial Pacific from 110°W to 170°W. The spring-time conditions were influenced by an El Niño that had disappeared before the fall cruises. This contributed to a large seasonal contrast in surface temperature, carbon, nutrient concentrations, and thermocline depth. Nitrate, total inorganic carbon, and fugacity of CO₂ values were significantly lower in the spring, while sea surface temperatures south of the equator were higher. The seasonal change in surface water chemistry at the equator is due to changes in upwelling of nutrient and carbon-enriched water. Oxygen and CO₂ anomalies at the surface point to approximately a three-fold increase in upwelling of thermocline water in the fall compared to the spring. The large-scale spatial variations in the surface chemistry patterns remained unchanged between spring and fall. There was a westward decrease in surface-water carbon and nitrate concentrations and a strong north to south asymmetry with higher carbon and nitrate values south of the equator. This pattern is attributed to input of carbon and nutrients with the South Equatorial Current from the east. Using velocities obtained from surface drifter tracks, along with reasonable gas exchange estimates and a "Redfield analysis" to account for export biological production, this westward decrease in carbon and nutrients can be quantitatively accounted for in the region from 0° to 3°S and 110°W to 140°W in the spring. In the fall the calculated concentration decrease is greater than observed, which is attributed to input from local equatorial upwelling along the pathway of water transit.

Willis, P.T., and J. Hallett. The cloud microphysical and electrical characteristics of a stratiform melting layer. Preprints, Conference on Cloud Physics, Dallas, TX, January 15-20, 1995. American Meteorological Society, Boston, 240-245 (1995).

No abstract.

Willis, P.T., R.A. Black, F.D. Marks, and D. Baumgardner. Airborne rain drop size distributions in TOGA-COARE. Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 431-433 (1995).

No abstract.

Willoughby, H.E. Eye thermodynamics. Preprints, 21st Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 24-28, 1995. American Meteorological Society, Boston, 357-358 (1995).

No abstract.

Willoughby, H.E. Normal-mode initialization of barotropic vortex motion models. Journal of the Atmospheric Sciences, 52(24):4501-4514 (1995).

An important limitation of numerical hurricane track forecasts is the difficulty in coaxing the vortex to assume the correct initial motion. Results from a semispectral, barotropic, linear model suggest a remedy. When the model is initialized from axisymmetry and rest in a quiescent environment on a northern hemisphere beta plane, the vortex moves toward the northwest. The asymmetric streamfunction field is a dipole such that flow between the cyclonic and anticyclonic gyres advects the vortex. This asymmetry appears to reflect a free oscillation because the asymmetric structure, and the induced motion, persists for a long time in the absence of forcing. When the beta effect is turned off, the motion continues on an f plane, and the dipole can be rotated and scaled to produce any desired initial motion. In the normal-mode interpretation, a vortex with cyclonic circulation throughout accelerates poleward rapidly because the beta effect forces a neutral mode at zero frequency. A vortex with angular momentum reduced to zero by encirclement of the cyclonic core with an annulus of anticyclonic flow experiences weaker forcing of a mode at the most anticyclonic orbital frequency of the axisymmetric circulation. Although the latter mode has a weak barotropic instability, acceleration along the curving track is slow, so that this vortex is promising for track forecasting. By careful choice of vortex position and the normal-mode asymmetry's amplitude and orientation at some time before the beginning of the forecast calculation, it is possible to "preinitialize" the vortex to pass through a target initial position at the initial time with an arbitrarily chosen initial velocity. In completely cyclonic vortices that have asymptotic decay of the swirling flow with radius, radial wave energy propagation damps the mode at zero frequency. Experimentation with a variety of axisymmetric vortex structures suggest that, with this single qualification, existence of the previously described modes is a general property of barotropic vortices scaled to resemble hurricanes.

Wilson, W.D., W.E. Johns, and S.C. Tosini. Windward Island Passages Monitoring Program: Physical oceanographic data collected on cruise WI-07 NOAA Ship Malcolm Baldrige, June 8-10, 1995. NOAA Technical Memorandum, ERL AOML-88 (PB96-135477), 95 pp. (1995).

Wilson, W.D., W.E. Johns, J.A. Routt, and M.D. Hendry. Windward Islands Passages Monitoring Program: Physical oceanographic data collected on cruises WI-04, HMBS Trident, 7-13 December 1992, WI-05, HMBS Trident, 7-12 February 1993, and WI-06, HMBS Trident, 24-28 March 1993. NOAA Technical Memorandum, ERL AOML-84 (PB95-208674), 112 pp. (1995).

During 1991, a collaborative program between the United States and Barbados was established with the support of NOAA's Climate and Global Change Atlantic Climate Change Program to conduct regular measurements of the transport and water mass characteristics in the major southern passages to the Caribbean Sea. This program involves the use of a Barbados Coast Guard vessel, the HMBS Trident, which makes routine monthly patrols in the area and has been equipped to collect standard hydrographic measurements (CTDO₂ profiles and water samples) and velocity profile measurements using a downward-looking acoustic Doppler current profiler (ADCP). The purpose of the program is to determine the quantity and time-variability of South Atlantic surface, thermocline, and intermediate waters flowing into the North Atlantic in compensation for southward cross-equatorial transport of North Atlantic Deep Water, and to establish an economical means for future monitoring of this transport loop. This report contains data collected on cruises WI-04, WI-05, and WI-06 of this program.

Yuter, S.E., R.A. Houze, B.F. Smull, F.D. Marks, J.R. Daugherty, and S.R. Brodzik. TOGA COARE aircraft mission summary images: An electronic atlas. Bulletin of the American Meteorological Society, 76(3):319-328 (1995).

An electronic atlas of research aircraft missions in TOGA COARE (Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment) has been prepared and is available on the Internet via World Wide Web browsers such as Mosaic. These maps are in the form of time sequences of color imagery assembled using the NCAR Zebra software. Initial versions of these maps were prepared in the field at the TOGA COARE Honiara Operations Center to aid in the evaluation of each aircraft mission immediately after it was flown. The maps prepared in the field have been updated, corrected, and remapped at standard scales and with common color schemes. They show the meteorological setting of sampling by all seven aircraft participating in TOGA COARE--the two NOAA WP-3D aircraft, the NCAR Electra, the FIAMS C-340, the UK C-130, and the NASA DC-8 and ER-2--by overlaying flight tracks, GMS satellite infrared data, and NOAA WP-3D airborne radar images. The map sequences are combined with text of scientists' notes and other background information on the research flights to form a summary of each aircraft mission. The resulting aircraft mission summaries are intended as a road map to the COARE aircraft dataset. They indicate where and when data were collected and the meteorological context for those data. As an electronic document, the atlas of aircraft mission summaries is available on demand, and it is dynamic: as further information becomes available, the mission summaries will continue to be added to and updated as appropriate, and new releases will be issued periodically. **1994**

Aberson, S.D., and M. DeMaria. Verification of a nested barotropic hurricane track forecast model (VICBAR). Monthly Weather Review, 122(12):2804-2815 (1994).

A nested analysis and barotropic hurricane track forecast model (VICBAR) was run for tropical cyclone cases in the North Atlantic basin during the 1989-1993 hurricane seasons. VICBAR is compared to the other operational hurricane track forecast models and is shown to perform as well as each of these. VICBAR forecasts are stratified by initial date, intensity, and location to assess the variability of model performance. VICBAR produces the best forecasts for hurricane cases, for cases initiated earliest in the hurricane season, for cases moving the most slowly northward, and for those moving westward. The forecasts with the largest errors are examined to illustrate the limitations of the model and to determine whether these cases can be identified operationally.

Atlas, D., and P.G. Black. The evolution of convective storms from their footprints on the sea as viewed by synthetic aperture radar from space. Bulletin of the American Meteorological Society, 75(7):1183-1190 (1994).

SEASAT synthetic aperture radar (SAR) echoes from the sea have previously been shown to be the result of rain and winds produced by convective storms; rain damps the surface waves and causes echo-free holes, while the diverging winds associated with the downdraft generate waves and associated echoes surrounding the holes. Gust fronts are also evident. Such a snapshot from 8 July 1978 has been examined in conjunction with ground-based radar. This leads to the conclusion that the SAR storm footprints resulted from storm processes that occurred up to an hour or more prior to the snapshot. A sequence of events is discerned from the SAR imagery in which new cell growth is triggered in between the converging outflows of two pre-existing cells. In turn, the new cell generates a mini-squall line along its expanding gust front. While such phenomena are well known over land, the spaceborne SAR now allows important inferences to be made about the nature and frequency of convective storms over the oceans. The storm effects on the sea have significant implications for spaceborne wind scatterometry and rainfall measurements. Some of the findings herein remain speculative because of the great distance to the Miami weather radar--the only source of corroborative data.

Atwood, D.K., A. Bratkovich, M.S. Gallagher, and G.L. Hitchcock. Introduction to the dedicated issue. Estuaries, 17(4):729-731 (1994).

No abstract.

Baringer, M.O., and R.A. Fine. Deep circulation in the western subtropical North Atlantic from Trident. Proceedings, Principal Investigators Meeting, Princeton, New Jersey, May 9-11, 1994. Atlantic Climate Change Program, 135-137 (1994).

No abstract.

Bitterman, D.S., and R.C. Millard. Shipboard thermosalinograph intercomparison test results from the NOAA research vessel Malcolm Baldrige. NOAA Technical Memorandum, ERL AOML-82 (PB95-147898), 47 pp. (1994).

An intercomparison test of three commercially available thermosalinographs (TSGs) considered for installation on volunteer observing ships of opportunity was conducted onboard the NOAA Ship Malcolm Baldrige during the period June 2 to September 22, 1993. A Seabird Electronics Company (SBE) Model SBE-21 TSG, a Falmouth Scientific Instruments, Inc. (FSI) TSG, and an Ocean Sensors Instrument, Inc. (OSI) Model OS-200 TSG were evaluated in the test. The three systems were plumbed in series and run continuously for all four months of the cruise. Temperature and conductivity measurements from each TSG were logged to a personal computer (PC). Water samples were drawn every six hours and analyzed for salinity. After removing anomalous sections of data, a drift rate for each instrument was then determined by comparing the thermosalinograph computed salinities to those from the water samples. The OSI thermosalinograph exhibited a salinity drift rate of +0.00738 practical salinity units (psu) per day, the FSI drift rate was +0.001 psu per day, and the SBE drift rate was +0.00063 psu per day. The salinity drift is composed of both conductivity and temperature drifts. The OSI and FSI temperature measurements exhibited systematic temperature errors under various conditions encountered during the test. The SBE TSG needs to improve the flushing of their conductivity cell.

Bitterman, D.S., and W.D. Wilson. A compact CTD system with programmable controller for obtaining in-situ water samples. Proceedings, IEEE Oceans '93 Conference, Victoria, British Columbia, October 18-22, 1993. Institute of Electrical and Electronic Engineers, Volume I, 144-148 (1994).

No abstract.

Black, R.A., H.B. Bluestein, and M.L. Black. Unusually strong vertical motions in a Caribbean hurricane. Monthly Weather Review, 122(12):2722-2739 (1994).

Unusually strong updrafts and downdrafts in the eyewall of Hurricane Emily (1987) during its rapidly deepening phase are documented by both in-situ aircraft measurements and a vertically pointing Doppler radar. Updrafts and downdrafts as strong as 24 and 19 m s^-1, respectively, were found. Mean updrafts and downdrafts were approximately twice as strong as those found in other hurricanes. Updrafts had approximately the same width as downdrafts. The most vigorous updrafts were located in the front quadrants of the storm, and most of the strongest downdrafts were found in the rear quadrants. The downdrafts could not be explained in terms of evaporative or melting cooling or precipitation drag. Evidence is presented that moist symmetric instability initiated by precipitation loading may have been responsible for the strong downdrafts.

Bogdanov, Yu.A., P.A. Rona, E.G. Gurvich, V.M. Kuptsov, N.A. Rimskij-Korsakov, A.M. Sagalevich, and M.D. Hannington. Relict sulphide mounds of the TAG hydrothermal field, Mid-Atlantic Ridge (26°N, 45°W). Okeanologiya, 34(4):590-599 (1994).

The huge inactive cone-shaped hydrothermal Mir Mound discovered and surveyed during the 23rd cruise of the R/V Akademik Mstislav Keldysh in 1991 has the base diameter of more than 700 m, the height of 50-70 m and the mass of hydrothermal material of about 10 million tons. In plan, the sound may be divided into two zones: the inner 400 m diameter zone with a dense "forest" of high-temperature sulphide chimneys and the more ancient outer zone (150-200 m) with lower temperature hydrothermal deposits of Fe and Mn hydroxides, opal and sometimes sulphides, partly covered by carbonate sediments. Radiocarbon dating showed that the formation of the mound had begun over 25,000 years ago. Over this time, hydrothermal activity occurred 23-25, 12-16 and 4-8 thousand years ago. Bottom photography, side scanning, and sediment analysis suggest the existence 2.5 km north of the Mir Mound of another inactive hydrothermal mound of similar dimensions.

Broecker, W.S., and T.-H. Peng. Stratospheric contribution to the global bomb radiocarbon inventory: Model versus observation. Global Biogeochemical Cycles,, 8:377-384 (1994).

An attempt is made, through modeling, to account for the decline in the ¹⁴C/C ratio in atmospheric CO₂ after its bomb-test-induced peak in 1963. The model suggests that as of 1964 about one-third of the bomb ¹⁴C remained in the stratosphere and that it was released to the troposphere with an e-folding time of about seven years. By contrast, measurements carried out in the stratosphere suggest that at that time the excess was closer to one quarter of the total and that the e-folding time for its decline was 3 ± 1 years. The anomaly between model and observation cannot be attributed solely to an inadequacy in the representation of the terrestrial biosphere. Rather, it must reflect either an inadequacy in the ocean model or in the measured stratospheric inventories.

Brundit, G., L. Krige, D.R. Palmer, A. Forbes, and K. Metzger. Acoustic thermometry of ocean climate: Feasibilty, Ascension-Cape Town. Proceedings, Second European Conference on Underwater Acoustics, Copenhagen, Denmark, July 4-8, 1994. Commission of the European Communities Federation of Acoustic Societies of Europe, Brussels, Luxembourg, Volume 2, 1019-1024 (1994).

No abstract.

Burpee, R.W., S.D. Aberson, P.G. Black, M. DeMaria, J.L. Franklin, J.S. Griffin, S.H. Houston, J. Kaplan, S.J. Lord, F.D. Marks, M.D. Powell, and H.E. Willoughby. Real-time guidance provided by NOAA's Hurricane Research Division to forecasters during Emily of 1993. Bulletin of the American Meteorological Society, 75(10):1765-1783 (1994).

The Hurricane Research Division (HRD) is NOAA's primary component for research on tropical cyclones. In accomplishing research goals, many staff members have developed analysis procedures and forecast models that not only help improve the understanding of hurricane structure, motion, and intensity change, but also provide operational support for forecasters at the National Hurricane Center (NHC). During the 1993 hurricane season, HRD demonstrated three important real-time capabilities for the first time. These achievements included the successful transmission of a series of color radar reflectivity images from the NOAA research aircraft to NHC, the operational availability of objective mesoscale streamline and isotach analyses of a hurricane surface wind field, and the transition of the experimental dropwindsonde program on the periphery of hurricanes to a technology capable of supporting operational requirements. Examples of these and other real-time capabilities are presented for Hurricane Emily.

Carsey, T.P., M.L. Farmer, C.J. Fischer, A. Mendez, A.A.P. Pszenny, V.B. Ross, P.-Y. Whung, M. Springer-Young, and M.P. Zetwo. Atmospheric chemistry measurements from the 1992 ASTEX/MAGE cruise, May 30-July 21, 1992 (cruise number 91-126). NOAA Data Report, ERL AOML-26 (PB95-179552), 90 pp. (1994).

The report describes the results of the 1992 ASTEX/MAGE cruise aboard the NOAA R/V Malcolm Baldrige. The cruise was designed to support research sponsored by the NOAA Climate and Global Change Program under: (1) the Marine Sulfur and Climate (MS&C) component of the Atmosphere and Land-Surface Processes Core Project, and (2) the Radiatively Important Trace Species (RITS) component of the Atmospheric Chemistry Core Project. Chemical and meteorological measurements obtained on the cruise include reduced sulfur gases, ozone, carbon monoxide, nitrogen oxides and peroxyacetyl nitrate, rawinsondes, aerosol chemistry, microwave radiometry, vertical wind profiles, heat and water momentum flux, non-methane hydrocarbons, trace metals, aerosol size distributions, aerosol physical properties, and surface water chlorophyll. The report contains a brief description of the experimental apparatus and procedures employed, plus graphic and tabular presentations of the data sets, for most of the data from AOML/Ocean Chemistry Division investigators.

Cione, J.J., and S. Raman. A three-dimensional numerical investigation of surface-induced coastal cyclogenesis near the Gulf Stream. Proceedings, Life Cycles of Extratropical Cyclones International Symposium, Bergen, Norway, June 27-July 1, 1994. Vol III, 52-55 (1994).

No abstract.

Cione, J.J., and S. Raman. Two-dimensional numerical simulations of Gulf Stream-enhanced offshore cold advection. Preprints, 6th Conference on Mesoscale Processes, Portland, Oregon, July 18-22 1994. American Meteorological Society, Boston, 270-273 (1994).

No abstract.

Clark, J.F., R.H. Wanninkhof, P. Schlosser, and H.J. Simpson. Gas exchange rates in the tidal Hudson River using a dual tracer technique. Tellus B, 46(4):274-285 (1994).

Gas exchange rates have been determined in the tidal Huson River by injecting two inert gases, ³He and sulfur hexafluoride (SF₆), and monitoring their decline with time. Their distributions along the main axis of the river were approximately Gaussian and maximum concentrations of excess ³He and SF₆ observed during each transect decreased from about 6500 × 10^-16 cm³ STP g^-1 and 250 ppt (part per trillion by volume), respectively, to values close to atmospheric equilibrium concentration were observed. After three days of mixing, tracer concentrations in bottom samples were 0-19% greater than in surface samples. Gas transfer velocities were calculated from the temporal change in the depth-averged excess ³He/SF₆ ratio from stations having maximum tracer concentrations. They ranged from 1.5 to 9.0 cm h^-1 and correlated well with mean wind speed.

Commons, D.N., J.R. Proni, and R. Fergen. Coastal oceanographic characteristics and their impact on marine biotoxicity studies during the SEFLOE II. Proceedings, Fourth Environmental Toxicology and Risk Assessment Symposium, Montreal, Quebec, Canada, April 11, 1994. American Society for Testing and Materials, 73-91 (1994).

A study, called the Southeast Florida Outfall Experiment II (SEFLOE II), was conducted from February 1991 through August 1992 at four open ocean outfalls to determine their effluent dispersion characteristics in the coastal ocean. The objectives of SEFLOE II were to assess the effect of the Florida Current and its associated spin-off eddies upon initial dilution and farfield dilution of the surfacing wastewater plumes in order to facilitate evaluation of mixing zone parameters, comparison of laboratory bioassay results to actual field bioassay results, evaluation of indicator bacteria die-off and dilution characteristics, and analysis of nutrient reductions as a function of distance and time. This paper deals with the impact of coastal oceanographic characteristics upon the biotoxicity aspect of the study. During the SEFLOE II study, a total of 1,727 acute bioassays (1,424 static acute screening bioassays and 303 static acute definitive bioassays) and 109 short-term chronic bioassays were analyzed. Plant whole effluent toxicity (WET) bioassays at different dilutions and time intervals were directly compared to bioassays analyzed on samples taken from the outfall dispersion plumes. These ocean bioassay results were then evaluated with contemporaneous current direction and speed data to determine initial and farfield dilutions and calculate actual Eulerian and Lagrangian exposure times. In all ocean bioassay tests no potential acute toxicity was demonstrated. SEFLOE II is a major investigation of the impact of a major ocean current on outfall plume behavior. The bioassay comparison indicated that standard bioassay methodology does not adequately take into consideration the substantial differences in dilution ratios and typical exposure times between laboratory analyses and actual environmental field conditions. The results of the study appear to indicate that a new look needs to be taken at bioassay methodology, especially for ocean outfalls based upon the initial and farfield mixing conditions.

Commons, D.N., J.R. Proni, H. Huang, W.P. Dammann, B.M. Goldenberg, J.G. Monson, and R.E. Fergen. Real world toxicity testing of an open ocean discharger. Proceedings, 66th Annual Conference and Exposition, Surface Water Quality and Ecology, Anaheim, CA, October 3-7, 1993. Water Environment Federation, Volume VII, 15-26 (1994).

A study, called the Southeast Florida Outfall Experiment II (SEFLOE II), was conducted from February 1991 through August 1992 at four open ocean outfalls. The objective of the study was to assess the effect of the Florida Current and coastal oceanographic characteristics upon the surfacing effluent plumes. During the study, the results from laboratory bioassays on plant effluent samples were compared with results from bioassays on contemporaneous ocean dispersion plume samples. Acute bioassay species used were the mysid Mysidopsis bahia and the estuarine fish Menidia beryllina. The mysid Mysidopsis bahia, and the estuarine fish Menidia beryllina, the sea urchin Arbacia punctulata, and the macroalga Champia parvula were the species used in short-term chronic bioassays during the SEFLOE II study. The results of these comparisons indicate a disparity between exposure times and dilutions in laboratory bioassays, and those exposure times and dilutions were actually demonstrated in the receiving waters.

Daneshzadeh, Y.-H., J.F. Festa, and S.M. Minton. Procedures used at AOML to quality control real time XBT data collected in the Atlantic Ocean. NOAA Technical Memorandum, ERL AOML-78 (PB94-173283), 50 pp. (1994).

The Atlantic Oceanographic and Meteorological Laboratory (AOML) is one of several Research Science Centers participating in a global effort to quality control oceanographic data collected from either research vessels or volunteer observing ships (VOS). AOML efforts are currently focused on XBT data collected in the Atlantic Ocean. The data being examined consists of "real-time," delayed, historical and Navy declassified modes. Quality control (QC) procedures developed and implemented at AOML for the examination of real time XBT data are presented. The steps required to QC XBT data are outlined in a "cookbook" format. The methods employed are primarily subjective, as many of the stages involve interactive input from the user.

DeMaria, M. An evaluation of the hydrostatic version of a new formulation of the primitive equations for atmospheric modeling. Preprints, 10th Conference on Numerical Weather Prediction, Portland, OR, July 18-22, 1994. American Meteorological Society, Boston, 443-445 (1994).

No abstract.

DeMaria, M., and J. Kaplan. A statistical hurricane intensity prediction scheme (SHIPS) for the Atlantic basin. Weather and Forecasting, 9(2):209-220 (1994).

A statistical model for predicting intensity changes of Atlantic tropical cyclones at 12, 24, 36, 48, and 72 h is described. The model was developed using a standard multiple regression technique with climatological, persistence, and synoptic predictors. The model developmental sample includes all of the named Atlantic tropical cyclones from 1989 to 1992, with a few additional cases from 1982 to 1988. The sample includes only the times when storms were over the ocean. The four primary predictors are (1) the difference between the current storm intensity and an estimate of the maximum possible intensity determined from the sea surface temperature, (2) the vertical shear of the horizontal wind, (3) persistence, and (4) the flux convergence of eddy angular momentum evaluated at 200 mb. The sea surface temperature and vertical shear variables are averaged along the track of the storm during the forecast period. The sea surface temperatures along the storm track are determined from monthly climatological analyses linearly interpolated to the position and date of the storm. The vertical shear values along the track of the storm are estimated using the synoptic analysis at the beginning of the forecast period. All other predictors are evaluated at the beginning of the forecast period. The model is tested using a jackknife procedure where the regression coefficients for a particular tropical cyclone are determined with all of the forecasts for that storm removed from that sample. Operational estimates of the storm track and initial storm intensity are used in place of best track information in the jackknife procedure. Results show that the average intensity errors are 10%-15% smaller than the errors from a model that uses only climatology and persistence (SHIFOR), and the error differences at 24, 36, and 48 h are statistically significant at the 99% level.

DeMaria, M., and J. Kaplan. Sea surface temperature and the maximum intensity of Atlantic tropical cyclones. Journal of Climate, 7(9):1324-1334 (1994).

An empirical relationship between climatological sea surface temperature (SST) and the maximum intensity of tropical cyclones in the North Atlantic basin is developed from a 31-year sample (1962-1992). This relationship is compared with the theoretical results described by Emanuel. The theoretical results are in agreement with the observations over a wide range of SST, provided that the tropopause temperature is assumed to be a function of SST. Each storm is examined to determine how close the observed intensity comes to the maximum possible intensity (MPI). Results show that only about 20% of Atlantic tropical cyclones reach 80% or more of their MPI at the time when they are the most intense. On average, storms reach about 55% of their MPI. Storms that are farther west and farther north tend to reach a larger fraction of their MPI. Storms are also more likely to reach a larger fraction of their MPI in August-November than in June-July. There is considerable interannual variability in the yearly average of the ratio of the observed maximum intensity to the MPI.

Donoso, M.C., J.E. Harris, and D.B. Enfield. Upper ocean thermal structure of the eastern tropical Pacific. NOAA Technical Report, ERL 450-AOML 36 (PB95-171781), 226 pp. (1994).

A rigorous quality control (QC) procedure developed to assure the research quality of upper ocean thermal data, mainly from expendable bathythermographs, is described in detail. The QC scheme takes into account recommendations from different data centers and is carried out completely by oceanographers. The region of interest corresponds to the tropical Pacific from 30ºN to 30ºS and from the dateline to the west coast of the Americas. For a 15 year period (1979-1993) 212,891 stations from five data sources (National Oceanographic Data Center, Joint Environmental Data Analysis Center, southeast Pacific, Navy declassified, and Tropical Ocean and Global Atmosphere Subsurface Data Center) were originally processed, of which 113,589 profiles were kept after rejecting duplicates and submitting the data to the scientific QC process. The accepted temperature-depth profiles were binned into boxes of 2 latitude by 5 longitude. The climatology and bimonthly thermal fields (sea surface temperature, temperature at 50 m, temperature at 100 m, temperature of the 0-400 m layer, 20ºC isotherm depth, and 15ºC isotherm depth) are mapped.

Feely, R.A., R.H. Wanninkhof, C.E. Cosca, M.J. McPhaden, R.H. Byrne, F.J. Millero, F.P. Chavez, T. Clayton, D.M. Campbell, and P.P. Murphy. The effect of tropical instability waves on CO₂ species distributions along the equator in the eastern equatorial Pacific during the 1992 ENSO event. Geophysical Research Letters, 21(4):277-280 (1994).

Tropical instability waves have been shown to have a major impact on the variability of temperature and nutrients along the equatorial wave guide. In order to assess the impact of these features on carbon species distributions during an ENSO event, sea surface temperature, salinity, sigma-t, nitrate, CO₂ fugacity, total inorganic carbon, total alkalinity, and pH along the equator were measured from 130°W to 100°W during 8-15 May 1992. Concurrent moored measurements of surface currents and temperature were also made at 0°, 110°W. Results indicate that tropical instability waves, with periods of 15-20 days and zonal wavelengths of 700-800 km, controlled the observed spatial variability of the CO₂ species, nitrate, and hydrographic parameters at the equator.

Forde, E.B., J.C. Hendee, and R.H. Wanninkhof. Hydrographic, carbon dioxide, nutrient, and productivity measurements from the South Atlantic during July and August of 1991. NOAA Data Report, ERL AOML-24 (PB94-180668), 96 pp. (1994).

From July 11 to September 2, 1991, the National Oceanic and Atmospheric Administration's (NOAA) Carbon Dioxide (CO₂) and Radiatively Important Trace Species (RITS) programs participated in an oceanographic research cruise conducted aboard the NOAA ship Malcolm Baldrige. This report presents the research from that cruise that was conducted for the CO₂ program, which has recently been renamed the Ocean-Atmosphere Carbon Exchange Study (OACES). During leg 1 of this cruise (Fortaleza, Brazil to Montevideo, Uruguay), 33 CTD hydrographic casts and 17 Go-Flo™ hydrographic (productivity) casts were conducted. Samples were also collected while underway on leg 1, for the determination of the fugacity of CO₂ (fCO₂) of the air and surface water. Leg 2 (Montevideo, Uruguay to Fortaleza, Brazil) collected 21 days of underway fCO₂ measurements, conducted five CTD hydrographic casts, and nine Go-Flo™ hydrographic (productivity) casts. This report contains tables of the following data: hydrography from each CTD cast at the bottle trip depths (including salinity, oxygen and nutrients), discrete carbon parameters, underway carbon parameter values, and data from productivity casts. Descriptions of the sampling techniques and analytical methods used in the collection and processing of these data are also presented in this report.

Gamo, T., H. Chiba, P. Fryer, J.-I. Ishibashi, T. Ishii, L.E. Johnson, K. Kelly, H. Masuda, S. Ohta, A.-L. Reysenbach, P.A. Rona, T. Shibata, J. Tamaoka, et al. Mariana 1992 diving surveys by Shinkai 6500 (Y9204 cruise): Revisits to the Mid-Mariana hydrothermal area and discovery of hydrothermal vents in the southern Mariana region. Journal of Deep Sea Research, 10:153-162 (1994).

We had ten dives of the submersible Shinkai 6500, together with its mothership Yokosuka, of JAMSTEC in the mid-to southern Mariana areas during November to December 1992. We revisited to the mid-Mariana Trough hydrothermal site (Alice Springs Field: 18°13'N, 144°42'E) five years after the discovery by the submersible Alvin in 1987. It was confirmed that the site had maintained the similar hydrothermal activity during the five years, because the highest fluid temperature (280°C), density of biological vent communities, and chemical composition of the hydrothermal endmember were compared well with those observed five years ago. In the southern Mariana area, we dove to an inner trench wall to recover ultramafic rocks originated from lower crust or upper mantle. Fresh basaltic lavas were found to outcrop on the side of a southern Mariana forearc fault, suggesting recent forearc volcanism related to the fault activity. In a transient zone between the southern Mariana arc and backarc systems, basaltic rocks with intermediate characteristics were recovered. It should be emphasized that a new hydrothermal vent site with 202°C fluid was discovered at the summit (depth: 1,470 m) of an arc seamount at (13°24'N, 143°55'E) in the southern Mariana Trough.

Garzoli, S.L., and C. Giulivi. What forces the variability of the southwestern Atlantic boundary currents? Deep-Sea Research, Part I, 41(10):1527-1550 (1994).

A marked variability in the location of the front originating at the confluence of the Brazil and Malvinas Currents has been observed from both surface and subsurface observations. Modeling experiments using climatological winds predict a seasonal variability on the latitude of separation of the Brazil Current from the coast. During the Confluence program (November 1988-February 1990) and from data collected with an array of inverted echo sounders, the location of the confluence front and its variability was established. In this paper, the observed oceanic variability is analyzed simultaneously with the wind product from the European Center for Medium Weather Forecast (ECMWF) obtained for the period of the observations. The ECMWF data is validated against in-situ indirect wind magnitude observations obtained from a sub-array of the Confluence deployments. The large-scale anomalies are explored through the comparison with the climatological wind fields obtained from Hellerman and Rosenstein (1983), Journal of Physical Oceanography, 13:1093-1104. From the analysis it is concluded that the main source of variability of the Confluence front is the local wind forcing. There is a variability in the location of the front due to the seasonal cycle of the winds in the South Atlantic. In addition to this seasonal variability, the latitude of separation of the Brazil Current from the coast presents a marked interannual variability that is forced from anomalous wind patterns south of the Confluence. There is no apparent correlation between wind-forced pulses in the Antarctic Circumpolar Current and the observed anomalous northward penetration of the Malvinas Current.

Garzoli, S.L., A.L. Gordon, and D. Pillsbury. Initial results from the BEST cruises. WOCE Notes, 6(1):10-11, 15 (1994).

No abstract.

Gould, W.J., Y. Desaubies, B.M. Howe, D.R. Palmer, F. Schott, and C. Wunsch. Acoustic thermometry in the Atlantic: A report to SCOR WG 96. Scientific Committee on Oceanic Research, International Council of Scientific Unions, 18 pp. (1994).

No abstract.

Gould, W.J., Y. Desaubies, B.M. Howe, D.R. Palmer, F. Schott, and C. Wunsch. Acoustic thermometry in the Atlantic. Proceedings, Second European Conference on Underwater Acoustics, Copenhagen, Denmark, July 4-8 1994. Commission of the European Communities Federation of Acoustic Societies of Europe, Brussels, Luxenbourg, Volume 2, 105-107 (1994).

No abstract.

Gray, W.M., C.W. Landsea, P.W. Mielke, and K.J. Berry. Predicting Atlantic basin seasonal tropical cyclone activity by 1 June. Weather and Forecasting, 9(1):103-115 (1994).

This is the third in a series of papers describing the potential for the seasonal forecasting of Atlantic basin tropical cyclone activity. Earlier papers by the authors describe seasonal prediction from 1 December of the previous year and from 1 August of the current year; this work demonstrates the degree of predictability by 1 June, the "official" beginning of the hurricane season. Through three groupings consisting of 13 separate predictors, hindcasts are made that explain 51%-72% of the variability as measured by cross-validated agreement coefficients for eight measures of seasonal tropical cyclone activity. The three groupings of predictors include (1) an extrapolation of quasi-biennial oscillation of 50- and 30-mb zonal winds and the vertical shear between the 50- and 30-mb zonal winds (three predictors); (2) west African rainfall, sea level pressure, and temperature data (four predictors); and (3) Caribbean basin and El Niño-Southern Oscillation information including Caribbean 200-mb zonal winds and sea level pressures, equatorial eastern Pacific sea surface temperatures and Southern Oscillation index values, and their changes in time (six predictors). The cross validation is carried out using least sum of absolute deviations regression that provides an efficient procedure for the maximum agreement measure criterion. Corrected intense hurricane data for the 1950s and 1960s have been incorporated into the forecasts. Comparisons of these 1 June forecast results with forecasts results from 1 December of the year previous and 1 August of the current year are also given.

Hacker, P., E. Firing, W.D. Wilson, R.L. Molinari, and M.H. Bushnell. Direct current velocity measurements during the Trident cruise in the subtropical western North Atlantic, August 1992. Proceedings, Principal Investigators Meeting, Princeton, New Jersey, May 9-11, 1994. Atlantic Climate Change Program, 162-165 (1994).

No abstract.

Hansen, D.V., M.S. Swenson, and M.C. Pazos. The Drifter Data Assembly Center. International WOCE Newsletter, 15:27-30 (1994).

No abstract.

Hendee, J.C. Data management for the Nutrient Enhanced Coastal Ocean Productivity program. Estuaries, 17(4):900-903 (1994).

The Nutrient Enhanced Coastal Ocean Productivity (NECOP) Data Management Program (NDMP) is designed to ensure tracking of samples and archival of all NECOP data in uniform formats, thus allowing ready access to data by NECOP investigators and the scientific community at large. The NDMP may broadly be described as possessing several functions: oceanographic sample tracking, data review and formatting, data dissemination, formation and supply of data products, and data transmittal to the National Oceanographic Data Center (NODC). Figure 1 gives an outline of data flow through the data manager, and is described below.

Hendee, J.C. Object-oriented database management system and their application to oceanography. Earth System Monitor, 4(4):6-9 (1994).

No abstract.

Houston, S.H., and M.D. Powell. Observed and modeled wind and water-level response from Tropical Storm Marco (1990). Weather and Forecasting, 9(3):427-439 (1994).

The Hurricane Research Division (HRD) analyzes surface wind fields in tropical storms and hurricanes using surface wind observations and aircraft flight-level wind measurements in the vicinity of the storms. The analyzed surface wind fields for Tropical Storm Marco (1990) were compared with the wind fields used for input in the National Weather Service's Sea, Lake, and Overland Surge from Hurricanes (SLOSH) model. The HRD wind fields were also used to determine the wind speeds and directions corresponding to the storm surge at tide gauges along Florida's west coast. The observed storm surge at the gauges was compared with the storm surge computed by the SLOSH model. Time series of the SLOSH model winds were compared with the time series based on the analyzed wind field at each tide gauge, because in most cases there were no wind observations available at these gauges. The comparisons of the analyzed and modeled winds and the observed and modeled storm surge show that the SLOSH model reasonably represented the extreme storm tide effects on two basins with relatively complicated coastlines. However, SLOSH overestimated surface winds in areas of offshore flow, resulting in predictions of excessive negative surge. It is suggested that real-time storm surge model calculations, based on input from real-time surface wind analyses, have potential for the support of emergency management response and infrastructure recovery efforts during and immediately following landfall.

Huang, H., J.R. Proni, and J.J. Tsai. Probabilistic approach to initial dilution of ocean outfalls. Water Environment Research, 66(6):787-793 (1994).

This paper presents a probabilistic approach to develop initial dilution criteria or standards for ocean outfall design and environmental impact assessment of effluent discharges. In contrast to a currently used "worst case" approach, in which a particular combination of parameters affecting initial dilution is specified and an associated initial dilution is calculated using a deterministic dilution model, the probabilistic approach provides a framework for combining data for the parameters which are often available in the form of time series or described in statistics; the result of the probabilistic approach is a description of initial dilution as a function of cumulative or exceedance probability, from which the exposure risk level to marine environment can be estimated and criteria or standards can be defined. The proposed methodology basically consists of implementing a probabilistic method with a deterministic initial dilution model. The probabilistic method could be time domain simulation, Monte Carlo simulation, or first-order uncertainty analysis; while the deterministic initial dilution model could be a mathematical model, a physical model, or an empirical equation. A case study is presented of the Miami-Central Outfall on the east coast of south Florida to compare the probabilistic approach with the "worst case" approach. In this case study, time domain simulation using actual data sets was employed to generate a time series of initial dilutions (dilutions were calculated using a semi-empirical equation). Some statistics of initial dilution were then obtained from the simulated dilution time series. It is found that for this case study the "worst case" dilution is 17.3 (minimum surface or near-surface dilution) and the associated cumulative probability of 5.4%.

Johnson, G.C., T.B. Sanford, and M.O. Baringer. Stress on the Mediterranean Outflow Plume: Part 1. Velocity and water property measurements. Journal of Physical Oceanography, 24(10):2072-2083 (1994).

In September 1988, six sections were occupied across the Mediterranean outflow plume in the Gulf of Cadiz, within 100 km of the Strait of Gibraltar. Vertical profiles of temperature and salinity were collected at CTD stations. Velocity and temperature profiles were collected with XCPs at a subset of these stations. At the channel base, the plume undergoes geostrophic adjustment and turns northwest to flow along the continental slope. There it decelerates and spreads gradually down the slope as friction slows the current and allows it to cross isobaths. Within the plume, downstream velocity and density increase rapidly in the interfacial layer with depth to the velocity maximum, or nose, -150 m above the bottom. Below the nose, in the bottom layer, downstream velocity decreases rapidly toward the bottom but the stratification is weak. Ekman-like veering occurs in the interfacial layer. Local bottom stresses on the plume are estimated by fitting the near-bottom velocity profiles to a log-layer model. These stresses are compared with bulk estimates of total stresses from momentum budget residuals (Baringer, 1993) and of interfacial stresses from combining the mean vertical shear with bulk turbulent dissipation estimates. The downstream pattern of the sum of the local bottom stresses and the bulk interfacial stresses agrees well in magnitude and distribution with that of the bulk total stresses. The largest stresses reach a mean of 5 Pa where the plume is flowing rapidly westward down a channel after exiting the strait, thinning and accelerating. These stresses are an order of magnitude larger than mean wind-stress values over the ocean gyres and exceed most bottom stress estimates in other regions.

Kendall, A.W., L.S. Incze, P.B. Ortner, S.R. Cummings, and P.B. Brown. Vertical distribution of eggs and larvae of walleye pollock (Theragra chalcogramma) in Shelikof Strait, Gulf of Alaska. Fisheries Bulletin, 92(3):540-554 (1994).

The vertical distribution of walleye pollock eggs and larvae in Shelikof Strait, Gulf of Alaska, was investigated using data from 36 Multiple Opening-Closing Net and Environmental Sensing System (MOCNESS) tows taken in April and May, 1986-1988. Most eggs were found from below 150 m to near bottom at depths of 300 m, but were progressively shallower later in the season. Eggs in middle stages of development were shallower than younger or older eggs. The vertical distribution of eggs was positively related to observed differences in seawater temperature but showed no relationship to density. Larvae hatch at incubation depth and quickly rise to the upper 50 m of the water column where they remain during larval development. Larger larvae ( 7-10 mm standard length [SL]) undergo limited diel vertical migration within the upper 50 m. They are deepest during the day, shallowest at dusk, slightly deeper at night, and even deeper at dawn. Their mean depths of occurrence were between 21 and 37 m at all times. At these depths, prey (copepod nauplii) generally were at densities sufficient for larval pollock growth in laboratory studies. Pronounced thermoclines and pycnoclines were present in the part of the water column inhabited by the larvae in late May. Larvae appear to remain below the upper mixed layer during periods of increased turbulence, but at depths during daytime where light was sufficient for feeding, and where prey densities were adequate.

Kenyon, T.N., and M.C. Pazos. Data from drifting buoys deployed in the equatorial Pacific between April 1, 1987 and June 30, 1988. NOAA Data Report, ERL AOML-25 (PB94-219177), 180 pp. (1994).

This data report covers the entire life (through August 31, 1989) of free drifting buoys released in the tropical Pacific Ocean by the Atlantic Oceanographic and Meteorological Laboratory (AOML) between April 1, 1987 and June 30, 1988. Excluded are those drifters released from Chinese research vessels which were covered in a separate report (Qiyu and Pazos, 1989).

Landsea, C.W., W.M. Gray, P.W. Mielke, and K.J. Berry. Forecasting seasonal Sahelian rainfall by 1 December of the previous year. Proceedings, International Conference on Monsoon Variability and Prediction, Trieste, Italy, WMO/TD No. 619. World Meteorological Organization, 496-503 (1994).

No abstract.

Landsea, C.W., W.M. Gray, P.W. Mielke, and K.J. Berry. Seasonal forecasting of Atlantic hurricane activity. Weather, 49:273-284 (1994).

No abstract.

Lawler, A.J., R.E. Fergen, A. Fairey, and J.F. Craynock. Comparison of acoustical and dye monitoring techniques for in-harbor mixing of Charleston's Plum Island Wastewater Treatment Plant effluent. Proceedings, Conference on Challenges and Opportunities in the Marine Environment, Washington, D.C., September 7-9, 1994. Marine Technology Society, 740-747 (1994).

The City of Charleston Plum Island Wastewater Treatment Plant (WWTP) discharges effluent through a multiport diffuser, designed for rapid initial dilution, into the Charleston Harbor. The original permit conditions for the Plum Island WWTP were based on initial dilution values determined by the EPA "initial dilution" model UPLUME. However, the City conducted a field study to determine actual instream waste concentration. A conventional dye study was performed by injecting a known amount of dye into the effluent and measuring the concentration of dye in the harbor. The second technology used was an innovative technique using acoustical backscatter data corrected to eliminate the background signal generated within the water column that is not related to the wastewater plume. Field data was used to determine an average initial dilution and farfield dilution during worst case (minimum mixing) conditions. Correlation of the two techniques provided validation of the acoustical methodology as an accurate measurement system for the determination of the dilution of the wastewater with distance from the outfall. In addition, the acoustic measurement gives continuous values, not just that of a given sampling point, and allows the entire plume configuration to be depicted pictorially. This allows the characterization of the microstructure in the rising plume and farfield plume that is not available with other techniques.

Lawler, A.J., R.E. Fergen, A. Fairey, and J.F. Craynock. Comparison of acoustical and dye monitoring techniques for in-harbor mixing of Charleston's Plum Island Wastewater Treatment Plant effluent. Proceedings, 66th Annual Conference and Exposition, Surface Water Quality and Ecology, Anaheim, CA, October 3-7, 1993. Water Environment Federation, Volume VII, 235-245 (1994).

Lee, W.-C., P.P. Dodge, F.D. Marks, and P.H. Hildebrand. Mapping of airborne Doppler radar data. Journal of Atmospheric and Oceanic Technology, 11(2):572-578 (1994).

Two sets of equations are derived to (1) map airborne Doppler radar data from an aircraft-relative coordinate system to an earth-relative coordinate system, and (2) remove the platform motion from the observed Doppler velocities. These equations can be applied to data collected by the National Oceanic and Atmospheric Administration WP-3D system, the National Center for Atmospheric research ELDORA system, and other airborne radar systems.

Lee, W.-C., F.D. Marks, and R.E. Carbone. Velocity track display: A technique to extract real-time tropical cyclone circulations using a single airborne Doppler radar. Journal of Atmospheric and Oceanic Technology, 11(2):337-356 (1994).

The concept and formulation of a real-time Doppler radar wind field analysis technique, velocity track display (VTD), is presented. The VTD algorithm is a harmonic analysis method similar to the velocity-azimuth display technique for ground-based radars; however, it is designed to deduce the primary circulation properties of atmospheric vortices such as tropical cyclones. When an aircraft equipped with a Doppler radar scanning in a track-orthogonal plane penetrates a cyclonic circulation, VTD decomposes Doppler velocities on cylindrical rings into tangential, radial, and the mean cross-track component of the wind velocity. Obtaining estimates of the vortex circulation requires data from only one aircraft flight leg instead of two in the pseudo-dual Doppler radar method. As a test, the VTD technique was applied to two orthogonal legs ("figure 4" pattern) in Hurricane Gloria (1985). The entire computation was completed about 15 min after the end of each flight leg with little or no human interaction. The reconstructed hurricane vortex structure (the mean tangential wind, mean radial wind, and the total tangential wind) is consistent with those documented in the literature by elaborate techniques that demand extensively interactive decisions and intensive computations. The output consists of about 4,000 Fourier coefficients, which can be transmitted from an aircraft to a forecast center via geosynchronous satellite link in real-time for further analysis and as initialization for tropical cyclone models. A version of VTD was run successfully on board a NOAA WP-3D during the 1991 hurricane season.

Lighthill, J., G. Holland, W. Gray, C.W. Landsea, G. Craig, J. Evans, Y. Kurihara, and C. Guard. Global climate change and tropical cyclones. Bulletin of the American Meteorological Society, 75(11):2147-2157 (1994).

This paper offers an overview of the authors' studies during a specialized international symposium (Mexico, 22 November-1 December 1993) where they aimed at making an objective assessment of whether climate changes, consequent on an expected doubling of atmospheric CO₂ in the next six or seven decades, are likely to increase significantly the frequency or intensity of tropical cyclones (TCs). Out of three methodologies available for addressing the question they employ two, discarding the third for reasons set out in the appendix. In the first methodology, the authors enumerate reasons why, in tropical oceans, the increase in sea surface temperature (SST) suggested by climate change models might be expected to affect either (i) TC frequency, because a well-established set of six conditions for TC formation include a condition that SST should exceed 26°C, or (ii) TC intensity, because this is indicated by thermodynamic analysis to depend critically on the temperature at which energy transfer to air near the sea surface takes place. Careful study of both suggestions indicates that the expected effects of increased SST would be largely self-limiting, (i) because the other five conditions strictly control how far the band of latitudes for TC formation can be further widened, and (ii) because intense winds at the sea surface may receive their energy input at a temperature significantly depressed by evaporation of spray, and possibly through sea surface cooling. In the second methodology, the authors study available historical records that have very large year-to-year variability in TC statistics. They find practically no consistent statistical relationships with temperature anomalies; also, a thorough analysis of how the El Niño-Southern Oscillation cycle influences the frequency and distribution of TCs shows any direct effects of local SST changes to be negligible. The authors conclude that, even though the possibility of some minor indirect effects of global warming on TC frequency and intensity cannot be excluded, they must effectively be "swamped" by large natural variability.

Maddox, R.A., and H.F. Bezdek. Surface wind-pressure gradient relationships in central Florida. Monthly Weather Review, 122(11):2596-2602 (1994).

An extended series of surface observations is used to compare observed surface winds with winds computed using the geostrophic relationship. These computations are done for both steady and unsteady wind regimes. Large differences are found in the comparisons of observed to computed winds. The differences exhibit pronounced seasonal and diurnal variability that appear to reflect both boundary layer stability and small-scale wind and pressure fields--for example, those attending land--sea breezes and thunderstorms. The results of this study may be useful to those engaged in studying global data sets and to modelers, who are continually challenged to improve the treatment of parameterization of turbulent processes. However, it is not obvious that any simple parameterization can be applied to obtain an accurate estimate of the surface wind in central Florida, given only the large-scale pressure gradient or a model-predicted wind above the surface as input. The use of the pressure field to estimate surface winds is an uncertain exercise at best.

Martin, J.H., K.H. Coale, K.S. Johnson, S.E. Fitzwater, R.M. Gordon, S.J. Tanner, C.N. Hunter, V.A. Elrod, J.L. Nowicki, T.L. Coley, R.T. Barber, S. Lindley, A.J. Watson, K. Van Scoy, C.S. Law, M.I. Liddicoat, R. Ling, T. Stanton, J. Stockel, C. Collins, A. Anderson, R. Bidigare, M. Ondrusek, M. Latasa, F.J. Millero, K. Lee, W. Yao, J.-Z. Zhang, G. Friederich, C. Sakamoto, F. Chavez, K. Buck, Z. Kolber, R. Greene, P. Falkowski, S.W. Chisholm, F. Hoge, R. Swift, J. Yungel, S. Turner, P. Nightingale, A. Hatton, P. Liss, and N.W. Tindale. Testing the iron hypothesis in ecosystems of the equatorial Pacific Ocean. Nature, 371(6493):123-129 (1994).

The idea that iron might limit phytoplankton growth in large regions of the ocean has been tested by enriching an area of 64 km² in the open equatorial Pacific Ocean with iron. This resulted in a doubling of plant biomass, a threefold increase in chlorophyll and a fourfold increase in plant production. Similar increases were found in a chlorophyll-rich plume downstream of the Galapagos Islands, which was naturally enriched in iron. These findings indicate that iron limitation can control rates of phytoplanton productivity and biomass in the ocean.

Mestas-Nunez, A.M., D.B. Chelton, M.H. Freilich, and J.G. Richman. An evaluation of ECMWF-based climatological wind stress fields. Journal of Physical Oceanography, 24(7):1532-1549 (1994).

A new mean monthly wind stress climatology based on seven years (1980-1986) of operational weather analyses by the European Centre for Medium-Range Weather Forecasts (ECMWF) has been derived by Trenberth et al. This climatology (referred to here as the TLO climatology) potentially represents a significant improvement over climatologies derived only from conventional wind observations. An attempt is made here to quantify the absolute accuracy of the TLO climatology by comparison with global wind stress fields constructed from vector winds measured by the SEASAT-A Satellite Scatterometer (SASS) during 1978. From a simulated SASS data set, it is shown that the magnitudes of the SASS stresses must be increased by about 7% to account for a systematic error that can be attributed to the scatterometer spatial- and temporal-sampling characteristics. After applying this correction, differences between the TLO climatology and SASS winds in the tropics are most likely related to known limitations of the ECMWF analyses. At latitudes south of 50°S, interannual variability and uncertainties in the operational weather analyses are o large that it is not possible to evaluate the TLO climatology on the basis of comparisons with SASS data. Outside of these equatorial and high southern latitude bands, the TLO stresses are shown to be systematically stronger than SASS by almost 50%. It is found that this difference can be entirely accounted for if the 1980-1986 ECMWF 1000-mb analyses are not interpreted as 10-m winds, as they were in constructing the TLO climatology. This conclusion is supported by an independent comparison of the synoptic ECMWF wind speed estimates with coincident buoy observations.

Millero, F.J., J.-Z. Zhang, E. Peltola, M. Roche, S. Olivella, M. De Alessi, and B. Vargas. Total alkalinity measurements in the South Pacific. University of Miami Technical Report, RSMAS-94-003, 207 pp. (1994).

In spring 1994, we participated in one CO₂ cruise in the South Pacific during the Joint Global Ocean Flux Study (JGOFS) sponsored by the National Oceanic and Atmospheric Administration (NOAA). This report gives the results of our pH, total alkalinity (TA), and total inorganic carbon dioxide (TCO₂) measurements made in the South Pacific during the cruise. The results were obtained by a potentiometric titration of seawater samples with HCl. Measurements on 116 samples of Certified Reference Material with the three cells at sea indicate that the systems have a reproducibility of ± 3.3 µmol kg^-1 in TA. The resulting pH, TA, and TCO₂ are thought to be precise to ± 0.01 in pH, ± 3 µmol/kg in TA, and ± 3 µmol/kg in TCO₂. Our titration results will be combined with the NOAA measurements of TCO₂ and fCO₂ to characterize the CO₂ system in this region.

Millero, F.J., J.-Z. Zhang, D.M. Campbell, W. Yao, K. Lee, M. Helmer, S. Mane, S. Olivella, S. Cass, D.G. Purkerson, J. Aicher, P.A. Steinberg, and D. Medina. Total alkalinity measurements in the eastern equatorial Pacific. University of Miami Technical Report, RSMAS-94-005, 229 pp. (1994).

In 1992, we made measurements on the carbonate system on two cruises (spring and fall) in the eastern equatorial Pacific during the Joint Global Ocean Flux Study (JGOFS) sponsored by the National Oceanic and Atmospheric Administration (NOAA). This report gives the results of our pH, total alkalinity (TA), and total inorganic carbon dioxide (TCO₂) measurements made during the spring and fall cruises. The results were obtained by a potentiometric titration of seawater with HCl acid. Measurements on the Certified Reference Materials during the cruise with the three cells indicate that the systems have a reproducibility of ± 2-4 µmol kg^-1 in TA. The titration values of TCO₂ determined on the Certified Reference Materials and the samples collected at sea were about 20 ± 6 µmol kg^-1 (spring) and 17 ± 6 µmol kg^-1 (fall) too high. This offset in TCO₂ is independent of depth and is due to the non-Nernstian Behavior of the electrodes. The measured values of pH, TA, and TCO₂ are thought to be precise too ± 0.01 in pH, ± 3 µmol kg^-1 in TA, and ± 5 µmol kg^-1 in TCO₂. These results will be combined with NOAA's AOML and PMEL groups to characterize the CO₂ system in this region.

Molinari, R.L., and E. Johns. Upper layer temperature structure of the western tropical Atlantic. Journal of Geophysical Research, 99(C9):18,225-18,233 (1994).

Mean monthly topographies of the 20°C and 10°C isothermal surfaces are used to describe the vertical displacements of the upper and lower thermocline in the western tropical Atlantic. The isotherm topographies are generated from expendable bathythermograph data collected between 1966 and 1993. The topographies confirm, and extend closer to the coast, earlier findings that demonstrate large spatial and temporal variability in the region. For example, the ridge and trough systems observed previously in the interior are shown, and their extension to the western boundary is described. In particular, it is shown that the ridge associated with the North Equatorial Countercurrent (NECC) extends from the interior northwestward along the western boundary, reaching farther north along the boundary in the upper thermocline than in the lower thermocline. South of the equator the northwestern corner of the countercurrent trough is apparent on the lower surface but not on the upper. The annual and semiannual harmonics of the vertical isotherm displacements account on the average for about 60% of the total variance on both surfaces. The horizontal structure of the first harmonic amplitude is similar for both surfaces, showing maximum amplitude along the axis of the NECC ridge. Minimum amplitudes are observed to the north along the axis of the NECC ridge. Minimum amplitudes are observed to the north along the axis of the countercurrent trough. These distributions are similar to the pattern of the first harmonic amplitude of the wind stress curl, supporting earlier studies of curl forcing of near-surface current features.

Molinari, R.L., D. Battisti, K. Bryan, and J. Walsh. Atlantic Climate Change Program. Bulletin of the American Meteorological Society, 75(7):1191-1199 (1994).

The Atlantic Climate Change Program (ACCP) is a component of NOAA's Climate and Global Change Program. ACCP is directed at determining the role of the thermohaline circulation of the Atlantic Ocean on global atmospheric climate. Efforts and progress in four ACCP elements are described. Advances include: (1) descriptions of decadal and longer term variability in the coupled ocean-atmosphere-ice system of the North Atlantic; (2) development of tools needed to perform long-term model runs of coupled simulations of North Atlantic air-sea interaction; (3) definition of mean and time-dependent characteristics of the thermohaline circulation; and (4) development of monitoring strategies for various elements of the thermohaline circulation.

Nelsen, T.A., P. Blackwelder, T. Hood, B. McKee, N. Romer, C. Alvarez-Zarikian, and S. Metz. Timed-based correlation of biogenic, lithogenic, and authigenic sediment components with anthropogenic inputs in the Gulf of Mexico NECOP study area. Estuaries, 17(4):873-885 (1994).

Hypotheses related to variability in seasonal hypoxic conditions, coastal nutrient enhancement, and offshelf transport of carbon on the Louisiana continental shelf were tested by characterization of biogenic, lithogenic, and authigenic components from two shelf and one Mississippi Canyon sediment cores. The authigenic-phase glauconite occurs above detection limits only in the core from the hypoxic area. A major increase in glauconite concentration was coincident with the onset (~1940) of the increased use of commercial fertilizers in the United States. In the same hypoxic-area core, benthic foraminifera species diversity decreases upcore from approximately the turn of the century to the present in a manner concurrent with glauconite and fertilizer increases. A subset of opportunistic benthic foraminifera species, known to become more prominent in stressed environments (i.e., hypoxic), increased upcore from ~52% of the total population at core bottom to ~90% at core top. These benthic foraminifera population and diversity changes were not apparent in a "control" core outside the area of documented hypoxia. Seaward of the shelf, in the Mississippi Canyon, coincident increases in sediment accumulation rate, percentages of coarse fraction and of organic carbon at core top indicate increased offshelf transport of carbon and other components. Quartz percentages indicate that episodic down-canyon transport has been active to core bottom (prior to the mid 1800s).

Nystuen, J.A. Inter-comparison of automatic rain gauges in optical rain gauge performance. Proceedings, Second Workshop on Optical Rain Gauge Measurements, Greenbelt, MD, April 21-22, 1994, O.W. Thiele, N.J. McPhaden, and D.A. Short (eds.). NASA Conference Publication 3288, 15-26 (1994).

No abstract.

Nystuen, J.A., J.R. Proni, C.A. Lauter, J.M. Bufkin, U. Rivero, M. Boland, and J.C. Wilkerson. APL disdrometer evaluation. NOAA Technical Memorandum, ERL AOML-83 (PB95-181681), 48 pp. (1994).

The Ocean Acoustics Division at the Atlantic Oceanographic and Meteorological Laboratory has evaluated a new disdrometer design developed by the Applied Physics Laboratory of John Hopkins University. Modified electronics have been added to the data processing circuitry to reduce temperature sensitivity and increase the dynamic range of the instrument. Calibration was performed using water drops from 0.6-5.5 mm diameter impacting the sensor head at terminal velocity. Field comparison to a Joss-Waldvogel disdrometer shows equal performance characteristics at low rainfall rates and slightly better performance for rainfall rates above 100 mm/hr. Engineering circuit design details and physical design of the calibration apparatus are described.

Ooyama, K.V. Another way of modeling the tropical cyclone. Proceedings, International Meeting on Numerical Prediction of Tropical Cyclones, Tokyo, Japan, January 17-21, 1994. Japan Meteorological Agency, Tokyo, 233-237 (1994).

No abstract.

Ooyama, K.V. Hurricane track and intensity predictions at HRD. Proceedings, International Meeting on Numerical Prediction of Tropical Cyclones, Tokyo, Japan, January 17-21, 1994. Japan Meteorological Agency, Tokyo, 85-89 (1994).

No abstract.

Price, J.F., and M.O. Baringer. Outflows and deep water production by marginal seas. Progress in Oceanography, 33(3):161-200 (1994).

Outflows of dense water from marginal seas provide a continuous renewal of the deep open ocean. Much of this water comes from one of four major outflows (Mediterranean Sea, Weddell Sea, and two from the Norwegian-Greenland Sea) that each have a characteristic property signature. Here we examine some of the processes that set these properties by reviewing historical data and by an analysis of numerical simulations. Our simulation model makes several of the streadtube approximations of Smith (1975), but goes on to include a Froude number-dependent parameterization of entrainment, a parameterization of broadening due to bottom drag, and it can accept real bottom topography and oceanic temperature and salinity profiles. This model is able to simulate some of the main features of each of the outflows, including the source to product water conversion process. The numerical simulation of the Mediterranean outflow is initialized at the west end of the Strait of Gibraltar (T=13.4°C and S=37.8 ppt) and allowed to flow freely into the Gulf of Cadiz. Within the first 50 km the outflow descends to about 600 m depth and accelerates to a maximum speed of about 1.2 m/s. This raises the Froude number above 1, and causes very strong entrainment of fresher, overlying North Atlantic Central Water. Entrainment more than doubles the volume transport and reduces the temperature and salinity to 12.4°C and 36.5 ppt, which reduces the density by about 1 kg/m³. Entrainment stops where the Coriolis force turns the outflow parallel to the local topography. The Mediterranean outflow continues on to Cape St. Vincent as a nearly geostrophic current that slowly descends the continental slope until becoming neutrally buoyant at a depth of about 1000 m, roughly consistent with the observed outflow. The other three outflows show a somewhat similar pattern in that strong entrainment generally occurs over short segments of the path where the bottom topography is relatively steep, typically just beyond the shelf-slope break. These outflows lose much less of their density anomaly (about 0.03 kg/m³ in the Weddell Sea case, about 0.1 kg/m³ in the Denmark Strait case, and about 0.2 kg/m³ in the Faeroe Bank Channel case) and continue to the bottom in their respective basins. They lose much less of their initial density primarily because there is less density contrast between these outflows and the overlying oceanic water; they reach the bottom primarily because the oceanic water column in polar and subpolar seas is very weakly stratified. This and other results indicate that the properties of the oceanic water column are of great importance in determining the product water of a marginal sea outflow.

Proni, J.R., H. Huang, and W.P. Dammann. Initial dilution of southeast Florida ocean outfalls. Journal of Hydraulic Engineering, 120(12):1409-1425 (1994).

Initial dilutions of four ocean outfalls (the Miami-Central, Miami-North, Hollywood, and Broward outfalls) on the east coast of south Florida were determined from dye and salinity studies. In the dye studies, continuous injections of the red dye Rhodamine-WT into effluent were conducted; dye concentrations were measured using a deck-mounted fluorometer with a ship-towed sampler and from grab water samples. In the salinity studies, temperature and conductivity were measured using a towed conductivity-temperature-depth device (CTD); salinity deficit was taken as a tracer to determine initial dilution. Results show that initial dilutions determined from both methods are consistent. Data for initial dilution and for environmental and effluent parameters are interpreted using the dimensional analysis method. A comparison is made between the present data and data from previous studies. Data for Hollywood and Broward outfalls (single-port discharges) are consistent with previous data. Data for Miami-Central and Miami-North outfalls (multiport diffuser discharges) are not consistent with data for single-port discharges. A value of C₁ = 0.15 for the asymptotic solution for the buoyancy-dominated nearfield is suggested.

Proni, J.R., W.P. Dammann, J.F. Craynock, H. Huang, D. Commons, R. Walker, J. Monson, P. Glynn, B. Goldenberg, R. Aceto, R. Fergen, J. Cowgill, and A. Gonzalez. SEFLOE II (Southeast Florida Outfall Experiment II) Final Report. Hazen and Sawyer, Hollywood, FL, Volume 1, 243 pp. (1994).

The SEFLOE II project is the result of a cooperative effort of several government agencies. The National Oceanic and Atmospheric Administration (NOAA) provided its extensive resources and was the lead agency for the project. The Broward County Office of Environmental Services (BCOES), City of Hollywood Utilities Department, and the Miami-Dade Water and Sewer Department collected and evaluated the chemical, bacteriological, and bioassay data on the individual outfalls. Hazen and Sawyer provided small boat operating assistance, overall program coordination among the utilities, and finalized the program report.

Rogers, R.F., J.M. Fritsch, and J.S. Kain. A new trigger function for mesoscale convective systems. Preprints, 10th Conference on Numerical Weather Prediction, Portland, OR, July 18-22, 1994. American Meteorological Society, Boston, 105-107 (1994).

No abstract.

Rosenthal, S.L. Statistical aspects of the precipitation regimes at Miami International Airport (MIA) and Palm Beach International Airport (PBI): 1961-1990. NOAA Technical Memorandum, ERL AOML-80 (PB94-194289), 40 pp. (1994).

Low-frequency components of the time series of mean annual precipitation for 1961-1990 at Miami International Airport (MIA) and Palm Beach International Airport (PBI) are closely in phase. The data show a decadal-scale variation with relatively high precipitation in the 1960s and 1980s and relatively low precipitation in the 1970s. This fluctuation is concomitant with a statistically significant decadal-scale fluctuation in tropical weather system frequency. MIA precipitation is systematically related to tropical weather system frequency on monthly and seasonal time scales but not so precisely that one can conclude a cause and effect relationship exists. Spectral analysis showed well marked peaks in the MIA and PBI spectra (computed from annual precipitation totals) at a period of 15 years. Both stations also showed considerable spectral intensity at a period of 10 years. Cospectral calculations indicated that the covariance of the MIA and PBI annual precipitation totals was primarily the result of fluctuations with periods of 10 years or more. The annual numbers of cloudy days (NCLD), thunderstorm days (NTWS), days with measurable precipitation (NP.01), and the precipitation total for the rainiest day of the year (P24X) at MIA were correlated with those from PBI. Positive correlations (significant at either the 95% or 99% level) were obtained in all four cases. The time series of annual values of NCLD showed statistically significant negative trends at both stations. In contrast, the annual values of NP.01 showed positive trends at these stations. Thus, the number of days with measurable rain at these stations increased over these 30 years while the number of cloudy days decreased. The time series of annual rainfall totals at both stations, when smoothed with five-year running means, showed maxima in the decade of the 1960s. Analyses of year-month cross sections showed that these maxima were the result of anomalously high rainfall in June and September-October during the later half of that decade.

Rosenthal, S.L. Variability of surface-air temperature and precipitation at Miami International Airport including relationships with tropical weather system activity and El Ni�o: 1941-1990. NOAA Technical Memorandum, ERL AOML-81 (PB94-216892), 38 pp. (1994).

The Miami International Airport (MIA) surface-air temperature and precipitation data for the period 1941-1990 were examined to determine El Ni�o's impact on the MIA climate. In this sample, El Ni�o years and the years just prior to El Ni�o years are relatively warm and the years that follow El Ni�o years are relatively cool. The MIA winter months in El Ni�o years tend to be relatively rainy in comparison to those of non El Ni�o years. The winter and spring of years preceding El Ni�o years tend to be relatively dry.

Samsury, C.E., and R.E. Orville. Cloud-to-ground lightning in tropical cyclones: A study of Hurricanes Hugo (1989) and Jerry (1989). Monthly Weather Review, 122(8):1887-1896 (1994).

Cloud-to-ground lightning characteristics of two Atlantic tropical cyclones of 1989, Hurricanes Hugo and Jerry, are presented. Statistics on the number of flashes, location, polarity, peak currents, and multiplicity (number of strokes per flash) are examined in an 18-hour period divided into pre-landfall and post-landfall categories. Land-based and aircraft lower fuselage radar data are also analyzed to determine the nature of the precipitation in which lightning is detected. Jerry is found to be more electrically active than Hugo, with 691 flashes detected compared with 33 flashes for Hugo. The majority of these flashes, regardless of the polarity, are located in the right front and right rear quadrants of the hurricanes, almost exclusively in outer convective rainbands. One reason for the large difference in the number of flashes between the two storms is the presence of many convective rainbands in Jerry, compared to only a few in Hugo. More than 20% of the flashes in each storm have a positive polarity. Median negative peak currents of the first return strokes are 49 kA in Hugo and 40 kA in Jerry. Median positive peak currents are 65 kA in Hugo and 52 kA in Jerry. The mean multiplicity of the negative flashes is 1.7 in Hugo and 2.6 in Jerry. 20% of the negative flashes detected in Jerry have a multiplicity of 4 or higher.

Smith, S.M., and G.L. Hitchcock. Nutrient enrichments and phytoplankton growth in the surface waters of the Louisiana Bight. Estuaries, 17(4):740-753 (1994).

Nitrate concentrations have increased twofold in the Mississippi River during the past three decades. The increased nitrogen loading to the Louisiana shelf has been postulated as a factor leading to eutrophication and the subsequent development of hypoxia west of the Mississippi River delta. While ratios of nitrogen:phosphorus and nitrogen:silica are relatively high in surface waters on the western Louisiana shelf, nitrogen has been posed as the "limiting" nutrient in this region. Bioassays were performed with nutrient additions to surface waters collected from the Louisiana shelf to examine the potential for specific nutrient limitation. Experiments were conducted in March and September 1991, and May 1992. The growth responses of natural and cultured phytoplankton populations were determined by measuring the time course of in vivo and 3-(3,4 dichlorophenyl)-1, 1-dimethylurea (DCMU)-induced fluorescence, as well as initial and final chlorophyll a concentrations. The results suggest that phosphate and silicate potentially limit phytoplankton growth during the winter-spring, particularly at low salinities. In late summer, in contrast, nitrogen limitation may be prominent at higher salinities.

Thacker, W.C., and R. Lewandowicz. Dynamics of information and uncertainty. Tellus A, 46(5):651-670 (1994).

The question of what information might be inferred from a set of data is posed in terms of the uncertainties of model variables determined by a least-squares fit. When a dynamical model is fitted to asynoptic data, the uncertainty can be characterized by a region in the model's phase space surrounding the point associated with the best fit. Changes in the shape and orientation of this region as it evolves indicate how information is redistributed dynamically among the model variables, much as kinetic and potential energy might be redistributed. These ideas are illustrated within the context of single and double oscillator systems. Information about the state of a shallow-water model is shown to depend sensitively on the sampling interval of fictitious altimetric data.

Thacker, W.C., and R. Raghunath. The rigid lid's contribution to the ill-conditioning of oceanic inverse problems. Journal of Geophysical Research, 99(C5):10,131-10,141 (1994).

Fitting oceanographic general circulation models to data is a difficult computational undertaking. This paper addresses difficulties stemming from the rigid lid approximation. Adjusting the barotropic stream function to achieve the fit, in effect, requires the solution of a hidden elliptical equation, the resolution-dependent difficulty of the elliptical problem manifest in the optimization problem. Adjusting the independent (subsurface) baroclinic velocity variables also contributes to the ill-conditioning of the least squares computation, but Lagrange multipliers can be used to adjust all baroclinic velocity variables (surface and subsurface) symmetrically. Similarly, Lagrange multipliers can be used to adjust the total velocity variables, thereby circumventing the use of barotropic stream function and baroclinic velocities; determining the multipliers at each optimization iteration requires the solution of an elliptical partial differential equation, the solution of which can be thought of as a preconditioning transformation.

Trefry, J.H., S. Metz, T.A. Nelsen, R.P. Trocine, and B.J. Eadie. Transport of particulate organic carbon by the Mississippi River and its fate in the Gulf of Mexico. Estuaries, 17(4):839-849 (1994).

This study was designed to determine the amount of particulate organic carbon (POC) introduced to the Gulf of Mexico by the Mississippi River and assess the influence of POC inputs on the development of hypoxia and burial of organic carbon on the Louisiana continental shelf. Samples of suspended sediment and supporting hydrographic data were collected from the river and >50 sites on the adjacent shelf. Suspended particles collected in the river averaged 1.8 ± 0.3% organic carbon. Because of this uniformity, POC values (in µmol l^-1) correlated well with concentrations of total suspended matter. Net transport of total organic carbon by the Mississippi-Atchafalaya River system averaged 0.48 × 10¹² moles y^-1 with 66% of the total organic carbon carried as POC. Concentrations of POC decreased from as high as 600 µmol l^-1 in the river to <0.8 µmol l^-1 in offshore waters. In contrast, the organic carbon fraction of the suspended matter increased from <2% of the total mass in the river to >35% along the shelf at >10 km from the river mouth. River flow was a dominant factor in controlling particle and POC distributions; however, time-series data showed that tides and weather fronts can influence particle movement and POC concentrations. Values for apparent oxygen utilization (AOU) increased from -60 µmol l^-1 to >200 µmol l^-1 along the shelf on approach to the region of chronic hypoxia. Short-term increases in AOU were related to transport of more particle-rich waters. Sediments buried on the shelf contained less organic carbon than incoming river particles. Organic carbon and delta ¹³C values for shelf sediments indicated that large amounts of both terrigenous and marine organic carbon are being decomposed in shelf waters and sediments to fuel observed hypoxia.

Wakimoto, R.M., and P.G. Black. Damage survey of Hurricane Andrew and its relationship to the eyewall. Bulletin of the American Meteorological Society, 75(2):189-200 (1994).

A damage map documenting Hurricane Andrew's destructive landfall over southern Florida is presented. Vectors that represent the direction of winds causing damage to trees and structures are shown along with an F-scale rating in order to assess the strength of the near-surface winds. It is hypothesized that increased surface roughness once the hurricane made landfall may have contributed to a surface wind enhancement resulting in the strongest winds ever estimated (F3) for a landfall hurricane. This intense damage occurred primarily during the "second" period of strong winds associated with the east side of the eyewall. For the first time, a well-defined circulation in the damage pattern by the second wind was documented. A superposition of radar data from Miami and Key West on top of the damage map provides the first detailed examination of the relationship between the eyewall and the surface flow field as estimated from the damage vectors.

Wang, C., and R.H. Weisberg. Equatorially trapped waves of a coupled ocean-atmosphere system. Journal of Physical Oceanography, 24(9):1978-1998 (1994).

Equatorially trapped waves of a simplified coupled ocean-atmosphere system are described by applying the formalism for conventional equatorially trapped waves with the assumption that the zonal wind stress and sea surface temperature perturbations are proportional. In this system, inertial-gravity and Rossby-gravity waves are unaffected by coupling whereas Rossby and Kelvin waves are affected, and in the low-frequency limit, these Rossby and Kelvin waves transform to slow westward and eastward propagating wave modes, respectively. The primary modifications by air-sea coupling are a decrease in phase speed and an increase in meridional scale. The properties of these coupled waves are useful in discussing several features, observed and modeled, relative to the evolution of the El Ni�o-Southern Oscillation.

Wang, C., and R.H. Weisberg. On the "slow mode" mechanism in ENSO-related coupled ocean-atmosphere models. Journal of Climate, 7(11):1657-1667 (1994).

A linear perturbation, coupled ocean-atmosphere model is revisited for further insights into El Ni�o-Southern Oscillation phenomenon. The model oscillates as a slow, eastward propagating mode interpreted as a divergence mode, whose energetics are controlled by the ocean. Growth requires that the work performed by the wind stress minus the work required to effect the ocean divergence exceeds the loss terms. The intrinsic scale of the atmosphere relative to the basin width is important. For sustainable oscillations, the ocean basin must be large enough so that oppositely directed divergence can develop on opposite sides of the basin. The global aspect of the atmospheric pressure field suggests that continental heating may provide either a direct source affecting adjacent oceans, or a connection between oceans. The important model parameters are the coupling and warming coefficients and the ocean Kelvin wave speed. The importance of the Kelvin wave speed derives from its specification of the background buoyancy state for the ocean. Upon further simplification, an analytical solution gives simialr parameter dependence as found numerically and shows that growth requires both large zonal wavelength and a zonal phase lag between the anomalies of wind stress and SST.

Watson, A.J., C.S. Law, K.A. Van Scoy, F.J. Millero, W. Yao, G.E. Friederich, M.I. Liddicoat, R.H. Wanninkhof, R.T. Barber, and K.H. Coale. Minimal effect of iron fertilization on sea-surface carbon dioxide concentrations. Nature, 371(6493):143-145 (1994).

It has long been hypothesized that iron concentrations limit phytoplankton productivity in some parts of the ocean. As a result, iron may have played a role in modulating atmospheric CO₂ levels between glacial and interglacial times, and it has been proposed that large-scale deposition of iron in the ocean might be an effective way to combat the rise of anthropogenic CO₂ in the atmosphere. As part of an experiment in the equatorial Pacific Ocean, we observed the effect on dissolved CO₂ of enriching a small (8 × 8 km) patch of water with iron. We saw significant depression of surface fugacities of CO₂ within 48 hours of the iron release, which did not change systematically after that time. But the effect was only a small fraction (similar to 10%) of the CO₂ drawdown that would have occurred had the enrichment resulted in the complete utilization of all the available nitrate and phosphate. Thus artificial fertilization of this ocean region did not cause a very large change in the surface CO₂ concentration, in contrast to the effect observed in incubation experiments, where addition of similar concentrations of iron usually results in complete depletion of nutrients. Although our experiment does not necessarily mimic all circumstances under which iron deposition might occur naturally, our results do not support the idea that iron fertilization would significantly affect atmospheric CO₂ concentrations.

Whung, P.-Y., E.S. Saltzman, and G.W. Gross. Uptake of methanesulfonate and sulfate in ice. Antarctic Journal of the United States, 29(5):73-75 (1994).

Methanesulfonate (MSA) is an atmospheric oxidation product of dimethyl sulfide; the latter is produced by phytoplankton in the surface ocean. Because of its biogenic origin, MSA can be used as a biological tracer in studies of atmospheric sulfur chemistry. The ratio of MSA to total non-seasalt sulfur has been used as an indicator for various atmospheric sulfur sources. Due to differences in physicochemical properties of MSA and sulfate, postdepositional processes could alter this fraction. Specifically, we address the question of whether there is a difference in the distribution coefficients (Conc._ice/Conc._water) of MSA and of sulfate. We also study the effect of ammonia on the uptake of MSA and sulfate in ice.

Whung, P.-Y., E.S. Saltzman, M.J. Spencer, P.A. Mayewski, and N. Gundestrup. Two-hundred year record of biogenic sulfur in a south Greenland ice core (20D). Journal of Geophysical Research, 99(D1):1147-1156 (1994).

The concentration of methanesulfonic acid (MSA) was determined in a shallow south central Greenland ice core (20D). This study provides a high-resolution record of the DMS-derived biogenic sulfur in Greenland precipitation over the past 200 years. The mean concentration of MSA is 3.30 ppb (sigma = 2.38 ppb, n=1134). The general trend of MSA is an increase from 3.01 to 4.10 ppb between 1767 and 1900, followed by a steady decrease to 2.34 ppb at the present time. This trend is in marked contrast to that of non-sea-salt sulfate (nss SO₄^2-), which increases dramatically after 1900 due to the input of anthropogenic sulfur. The MSA fraction ((MSA/(MSA+nss SO₄^2-)) * 100) ranges from a mean of 15% in preindustrial ice to less than 5% in recent ice. These MSA fractions suggest that approximately 15 to 40% of the sulfur in recent Greenland ice is of biological origin. It is suggested that there is a significant low-latitude component to the biogenic sulfur in the core and that variations in the MSA fraction reflect changes in the relative strengths of low- and high-latitude inputs. The data show no evidence for a strong dependence of dimethyl sulfide (DMS) emissions on sea surface temperature during the last century. There is also no indication that the yield of MSA from DMS oxidation has been altered by increased NO_x levels over the North Atlantic during this period.

Willis, P.T., J. Hallett, R.A. Black, and W. Hendricks. An aircraft study of rapid precipitation development and electrification in a growing convective cloud. Atmospheric Research, 33:1-24 (1994).

The rapid initial precipitation growth and initial electrification of a convective cloud, growing as a new cell on the upshear side of a cloud system in Florida, is traced from radar data and aircraft penetrations at the -7°C to -10°C level. This study combines radar, microphysical, and electrical measurements so that an examination of the interactions between the cloud dynamics, microphysics, and electrification is possible. The first pass (-7°C) was characterized by a strong 23 m/s updraft, all liquid cloud water, no precipitation, and no significant electrification. In the 300 s between the two penetrations, precipitation developed very rapidly from <15 dBZ to >45 dBZ, and the vertical component of the electric field increased from below the measurement threshold to -25 kv/m. The second penetration, which started at -7°C and ended at -10°C, was still exclusively updraft, but with lesser peak velocities and a more complex structure; i.e., no downdraft, but with relative minima in the updraft. The microphysics of the second pass displayed a segment of exclusively cloud liquid water (no precipitation size hydrometeors), a small segment of all liquid precipitation size hydrometeors, a small region of mixed hydrometeors and an extensive region of graupel hyrdometeors, ranging in size from 100 µm to several mm. High cloud liquid water coexisted with the liquid and graupel by hydrometeors in the strong updrafts. The electrification was observed to occur exclusively in the segments of the cloud pass where graupel were observed. Within this graupel region, where the graupel often coexisted with supercooled cloud liquid water, a significant electric field occurred only at relative minima in the updraft. These relative velocity minima were also minima in the cloud liquid water content. The observed updraft velocities in these relative minima were close to balance velocities for the observed larger graupel hydrometeors. The strongest updrafts, where the formation and the riming growth of graupel was the greatest (maxima in cloud liquid water content), were not the locations of significant electrification at this flight level.

Willoughby, H.E. Mature structure and evolution. In Global Perspectives on Tropical Cyclones, R.L. Elsberry (ed.). World Meteorological Organization, Geneva, pp. 21-62 (1994).

No abstract.

Willoughby, H.E. Nonlinear motion of a shallow water barotropic vortex. Journal of the Atmospheric Sciences, 51(24):3722-3744 (1994).

Nonlinear motions of a shallow water barotropic vortex on a beta plane differ substantially from the analogous linear motions. The nonlinear model described here, in which wavenumber 1-3 asymmetries interact with each other and the mean vortex, predicts that an initially completely cyclonic vortex will accelerate toward the north-northwest, reaching a speed of 2.5 m s^-1 at 48 h. During the rest of the 240-h calculation, the speed varies by <0.5 m s^-1 as the direction turns from north-northwest to northwest. The vortex accelerations are in phase with temporal changes of vortex-relative angular momentum (L_R). The turning back of track coincides with a transition of the wavenumber 1 asymmetry from a single dipole to double dipole. The latter structure appears to be another orthogonal solution of the second-order radial structure equation for a neutral linear normal mode. The corresponding linear model, in which forces only wavenumber 1, shows only the single dipole structure and straight north-northwest accelerating motion that reaches a speed of 9 m s^-1 at 240 h. The slower motion in the nonlinear model stems from wave-induced changes in the axisymmetric vortex and vacillation between the orthogonal and modal structures. A nonlinear calculation with zero initial L_R on a beta plane follows a curving path dictated by a barotropically unstable linear mode for the first 144 h. Subsequently, the double dipole structure for that mode appears as the track turns toward the northwest and the speed accelerates from 1 to 2 m s^-1. A spatially uniform geostrophic environment on an f plane causes vortex motion by advection and by propagation. The potential vorticity (PV) gradient due to the current acts as much as beta does. Although the PV gradient is typically 0.1 of that due to beta, the induced propagation toward high potential vorticity is 1/2-1/4 of that on a beta plane because superposition of the vortex on a geopotential gradient amplifies the PV gradient's effect. In a quiescent environment on an f plane, initial asymmetries that project onto the normal modes induce long-lasting motion that retains about half its speed to 240 h. If the initial speed is <2 m s^-1, vacillation between orthogonal modal structures may cause dramatic turns and accelerations of the vortex track.

Willoughby, H.E. The Twentieth Conference on Hurricanes and Tropical Meteorology. Bulletin of the American Meteorological Society 75(4):601-611 (1994).

No abstract.

Wilson, W.D. Deep ocean current profiling with a lowered broadband acoustic Doppler current profiler. Proceedings, Oceans '94 Conference, Brest, France, October 1994. Institute of Electrical and Electronics Engineers, New York, 660-665 (1994).

An RD Instruments 150 kHz broadband acoustic Doppler current profiler (ADCP) has been mounted on a CTD frame and used to measure current velocity shear below the instrument during casts as deep as 5500 m. By using processing techniques similar to those described by Firing and Gordon for (1) a 300 kHz narrowband ADCP and Fischer and Visbeck and (2) a 150 kHz narrowband ADCP, as well as some more recently developed algorithms, the raw profiles are merged with CTD data, corrected, edited, integrated, and averaged to produce unreferenced profiles of current velocity. Using GPS navigation data and the measured velocities, the profiles are referenced to produce absolute velocity profiles for both the upcasts and downcasts. This paper describes data collection and processing procedures, instrument settings, and modifications made to the standard self-contained instrument to accommodate an external, rechargeable battery pack. The absolute velocity profiles obtained compare favorably with simultaneous Pegasus measurements. During five such comparisons made on a cruise in the equatorial Atlantic Ocean in June 1993, depth-averaged eastward and northward velocity components agreed to an average of 0.3 cm s^-1 with an rms difference of 0.7 cm s^-1; absolute velocity comparisons between the instruments compare favorably. The lowered ADCP (LADCP) provides full water column absolute velocity profiles, coincident with CTD measurements, with the accuracy of a Pegasus profiler. It has the advantage of not requiring any extra shiptime and being independent of auxiliary bottom-mounted hardware. For use in this application, the RD Instruments high-powered 150 kHz broadband ADCP used seems to have advantages over both the 150 and 300 kHz narrowband instruments.

Wilson, W.D., E. Johns, and R.L. Molinari. Upper layer circulation in the western tropical North Atlantic Ocean during August 1989. Journal of Geophysical Research, 99(C11):22,513-22,523 (1994).

Shipboard acoustic Doppler current profiler (ADCP) current velocity and CTD temperature, salinity, and dissolved oxygen measurements are used to map the flow field above the sigma_theta = 26.8 isopycnal (approximately the upper 300 m of the water column) in the North Brazil Current (NBC) retroflection region (0° to 14°N, 60° to 40°W) during August of 1989. The water column is divided into a near surface, upper thermocline layer (above sigma_theta = 24.5), and a main to sub-thermocline layer (sigma_theta = 24.5 to sigma_theta = 26.8). In the upper layer, the eastward flowing North Equatorial Countercurrent (NECC) is composed of 16 × 10⁶ m³/s of NBC transport that has retroflected from the coast between 6°N and 8°N, and 8 × 10⁶ m³/s of North Equatorial Current (NEC) transport returning eastward. An anticyclonic eddy with a 10 × 10⁶ m³/s transport lies northwest of the NBC retroflection. No throughflow is observed along the boundary, and only a small portion of the observed NEC transport (1.5 × 10⁶ m³/s) enters the Caribbean Sea. In the lower layer, the NBC transports 8 × 10⁶ m³/s into the subthermocline North Equatorial Undercurrent (NEUC). In addition, 15 × 10⁶ m³/s joins the NEUC from the north. At 44°W the subsurface core of the NEUC lies south of the near-surface core of the NECC. Nearly half of the NEUC transport is made up of a mixed water type with salinity-oxygen (S-O₂) characteristics intermediate to the characteristics of the original component transports. There is no evidence of continuous NBC flow into the Caribbean Sea in the lower level. The closed eddy to the north of the retroflection, however, contains water masses with South Atlantic S-O₂ properties.

Wilson, W.D., W.E. Johns, and M.D. Hendry. Measurements of current structure and transport in the Windward Islands Passages: 1991-1993. Proceedings, Principal Investigators Meeting, Princeton, New Jersey, May 9-11, 1994. Atlantic Climate Change Program, 168-172 (1994).

No abstract.

Wilson, W.D., W.E. Johns, J.A. Routt, and M.D. Hendry. Windward Islands Passages Monitoring Program: Physical oceanographic data collected on cruises WI-02, HMBS Trident, 6-10 May 1992 and WI-03, HMBS Trident, 19-23 September 1992. NOAA Technical Memorandum, ERL AOML-79 (PB94-194131), 107 pp. (1994).

During 1991, a collaborative program between the U.S. and Barbados was established with support from the United States NOAA/CGC/ACCP to conduct regular measurements of the transport and water mass characteristics in the major southern passages to the Caribbean. This program involves the use of a Barbados Coast Guard vessel (the HMBS Trident) that makes routine patrols in this area, which has been equipped to collect standard hydrographic measurements using a Conductivity-Temperature-Depth-dissolved Oxygen (CTDO₂) and velocity profile measurements on station using a downward-looking acoustic Doppler current profiler (ADCP). The purpose of the program is to determine the quantity and time-variability of South Atlantic surface, thermocline, and intermediate waters flowing into the North Atlantic in compensation for southward cross-equatorial transport of North Atlantic Deep Water, and to establish an economical means for future monitoring of this return flow. This report contains data from cruises WI-02 and WI-03 conducted May 6-10, 1992 and September 19-23, 1992, respectively.

Zhang, J.-Z., and F.J. Millero. Investigation of metal sulfide complexes in seawater using cathodic stripping square wave voltammetry. Analytica Chimica Acta, 284(3):497-504 (1994).

Cathodic stripping square wave voltammetry has been used to detect H₂S in seawater over a wide range of concentrations (nM to mM). The addition of metal ions to the solutions was found to depress the signal. This depression was attributed to the formation of metal sulfide complexes [MHS⁺, M(HS)₂]. Stability constants for the formation of sulfide complexes with Cd²⁺, Cu²⁺, Cu⁺, Pb²⁺, Zn²⁺, Co²⁺, Fe²⁺, Mn²⁺, Ni²⁺, and Hg²⁺ have been estimated in sea water at pH 8.0 and 25°C using this method. The stability constants of cadmium sulfide complexes (log beta_CdHS = 6.3 and log beta_Cd(HS)2 = 12.7) were found to be in reasonable agreement with previous measurements. The values of log beta_CuHS = 7.0 and log beta_Cu(HS)2 = 13.0; log beta_PbHS = 7.1 and log beta_Pb(HS)2 = 13.5; log beta_ZnHS = 6.0 and log beta_Zn(HS)2 = 13.7; log beta_FeHS = log beta_Co(HS) = log beta_NiHS = 5.3 and log beta_Mn(HS) = 6.7 were also obtained. Correction for the formation of strong chloro complexes for Hg²⁺ and Cu⁺ in seawater gave measured values close to the literature values. The results have been used to determine the speciation of HS^- in surface seawater and of a number of metal ions in various anoxic basins.

Zhang, J.-Z., and F.J. Millero. Kinetics of oxidation of hydrogen sulfide in natural waters. In Environmental Geochemistry of Sulfide Oxidation, C.N. Alpers and D.W. Blowes (eds.). American Chemical Society, Washington, D.C., 393-409 (1994).

Recently we have studied the oxidation of H₂S with O₂ in natural waters as a function of pH (4 to 10), temperature (278.15 to 338.15 K), and salinity (0 to 36). The major products formed from the oxidation of H₂S were SO₃^2-, S₂O₃^2-, and SO₄^2-. A kinetic model was developed to predict the distribution of the reactants and products over a wide range of conditions. Dissolved and particulate metals have a significant effect on the rates of oxidation and the product formation. Field measurements made in the Black Sea, Framvaren Fjord, Chesapeake Bay, and Cariaco Trench are in reasonable agreement with the values predicted from laboratory studies at the same concentration of Fe²⁺. **1993**

Aberson, S.D., M. DeMaria, and R.E. Kohler. A four year (1989-1992) sample of a nested barotropic hurricane track forecast model (VICBAR). Preprints, 20th Conference on Hurricanes and Tropical Meteorology, San Antonio, TX, May 10-14, 1993. American Meteorological Society, Boston, 292-295 (1993).

No abstract.

Bergamasco, A., P. Malanotte-Rizzoli, W.C. Thacker, and R.B. Long. The seasonal steady circulation of the eastern Mediterranean determined with the adjoint method. Deep-Sea Research, Part II,40(6):1269-1298 (1993).

In this paper we use a rather unconventional approach to determine the steady seasonal circulation of the eastern Mediterranean. Traditional calculations rely either on prognostic models spun-up with different forcing functions or on inverse methods having rather simple dynamics. In the present applications one of the most sophisticated inverse techniques, the adjoint method of control theory, is used to find the model state that is optimally consistent with the model dynamics, with a prescribed climatology and is steady in time. The model used is the GFDL primitive equation model in its fully time-dependent non-linear version forced by seasonal wind-stress fields that are kept steady for each calculation. The prescribed climatology consists of the seasonal hydrographies of the temperature and salinity fields. Steadiness upon the seasonal time scale is required as a term in the cost function of the adjoint that penalizes the tendencies of the prognostic variables. This use of the adjoint method reconstructs the steady seasonal wind-driven circulation in an ocean with a prescribed baroclinic structure. As such, it is equivalent to a prognostic spin-up calculation with steady winds and the robust diagnostic applied, i.e., adding a term that relaxes the temperature and salinity fields to the seasonal climatologies with a time constant of three months. To assess the "success" of these calculations, the success of the inversion must be quantified. The examination of the final data misfits and steady state residuals shows that steady state has indeed been reached. The steady-state residuals are always much smaller than the data misfits and both of them are always small, well below the one standard deviation value for each field. Thus, we can assess that a meaningful solution had indeed been attained. To assess further if these solutions are reasonable, we have carried out for comparison robust diagnostic calculations with a time constant of three months. The circulations thus obtained are extremely similar to the adjoint solutions in reproducing the overall patterns as well as the individual sub-basin scale gyres and interconnecting currents and meandering jets. The circulations obtained with the two approaches are also equally strong. However, both the adjoint and the robust diagnostic results produce an overall barotropic transport that is one order of magnitude bigger than that observed. They also both show anomalously strong vortex structures in regions of sharp topographic breaks connecting the deep interior to the shelves, for which no observational evidence is available. These unrealistic features can be explained by taking into account that with the short time scale of three months used in both approaches biased solutions may be obtained. These biases are due to inconsistencies between the rough topography used and the smooth climatologies, that lead to a misrepresentation of the important JEBAR effect. This explanation is supported by a further robust diagnostic calculation in which the time constant is increased in the deep layers that gives a circulation intensity much more realistic.

Bitterman, D.S., and D.V. Hansen. Evaluation of sea surface temperature measurements from drifting buoys. Journal of Atmospheric and Oceanic Technology, 10(1):89-96 (1993).

Three drift-buoy designs have been deployed since 1988 in substantial numbers in the tropical Pacific Ocean by United States participants as part of the Tropical Ocean Global Atmosphere (TOGA) Pan Pacific Surface Current Study. These include the Low Cost Tropical Drifter designed and built at the Atlantic Oceanographic and Meteorological Laboratory, the Low Cost Drifter (LCD) designed and built by the Massachusetts Institute of Technology Draper Laboratories, and the Ministar Drifter designed and built at the Scripps Institution of Oceanography and built by Technocean Inc., San Diego, California, which has subsequently become known as the World Ocean Climate Experiment standard drifter. This report contains an evaluation of the performance of the sea surface temperature measurement system carried by these buoy designs. Based on comparisons of the monthly mean SST derived from the available XBT and CTD casts and on intercomparisons among each of the buoy types, all three designs appear to include a warm bias in the surface temperatures they report. The LCD showed a larger mean bias and diurnal variation from solar heating than the other two buoy types. This difference is probably due to the location chosen for its sensor, resulting in poor thermal contact with the surrounding water.

Black, M.L. Comparisons of tropical cyclone intensity with eyewall vertical velocities. Preprints, 20th Conference on Hurricanes and Tropical Meteorology, San Antonio, TX, May 10-14, 1993. American Meteorological Society, Boston, 520-523 (1993).

No abstract.

Black, M.L., and P.P. Dodge. Time-lapse radar images of Hurricanes Hugo (1989) and Andrew (1992). Preprints, 26th International Conference on Radar Meteorology, Norman, OK, May 24-28, 1993. American Meteorological Society, Boston, 97-99 (1993).

No abstract.

Black, P.G., and A.V. Litinetski. Mesoscale fields in Hurricane Gilbert according to data measurements by airborne meteorological laboratories. Meteorology and Hydrology (in Russian), 2:27-37 (1993).

No abstract.

Black, R.A., J. Hallett, and C.P.R. Saunders. Aircraft studies of precipitation and electrification in hurricanes. Preprints, Conference on Atmospheric Electricity, St. Louis, MO, October 4-8, 1993. American Meteorological Society, Boston, J20-25 (1993).

No abstract.

Black, R.A., P.T. Willis, and J. Hallett. The development of ice particles and the establishment of electric fields in a maritime tropical cumulus cloud. Preprints, 20th Conference on Hurricanes and Tropical Meteorology, San Antonio, TX, May 10-14, 1993. American Meteorological Society, Boston, 81-84 (1993).

No abstract.

Bliven, L.F., J.-P. Giovanangeli, R.H. Wanninkhof, and B. Chapron. A laboratory study of friction-velocity estimates from scatterometry: Low and high regimes. International Journal of Remote Sensing, 14(9):1775-1785 (1993).

Measurements from scatterometers pointing at wind-waves in three large wave-tanks are examined to study fetch effects and the correlation with wind friction-velocity u_*. Time-series measurements were made at 13, 35, and 95 m with a K_a-band scatterometer aimed upwind at 30° incidence angle and vertical polarization. Average normalized radar cross-section sigma_o values from all fetches follow a common trend for sigma_o as a function of u_*, so the fetch dependence is negligible. An empirical power-law model yields a high correlation between sigma_o and u_*, but because systematic anomalies arise, we re-examine a turbulence approach that delineates low and high regimes with a transition at u_* of approximately 25 cm s^-1. Using this criteria, the data are well represented by a two-section power-law relationship between sigma_o and u_*.

Bougault, H., J.L. Charlou, Y. Fouquet, H.D. Needham, N. Vaslet, P. Appriou, P.J. Baptiste, P.A. Rona, L. Dmitriev, and S. Silantiev. Fast and slow spreading ridges: Structure and hydrothermal activity, ultramafic topographic highs, and CH₄ output. Journal of Geophysical Research, 98(B6):9643-9651 (1993).

Different parts of the world ridge system have quite different morphologies, which reflect different constructional processes. It appears that hydrothermal circulation at all spreading centers is an important exchange process between the ocean and the newly formed oceanic crust. This hydrothermal circulation may vary according to morphology and crustal composition and may also affect ridge constructional processes. The TAG (26°N) and Snake Pit (23°N) hydrothermal sites on the Mid-Atlantic Ridge (MAR) display Mn/CH₄ ratios in overlying seawater similar to those of nonsedimented East Pacific Rise sites, i.e., about 0.2 mol/L. In contrast, large methane anomalies with very low Mn/CH₄ ratios of 0.005 mol/L are associated with ultramafic topographic highs near 15°N, close to the axis and on ultramafic walls of the rift valley. The association of ultramafic bodies and CH4 anomalies in seawater indicates active serpentinization processes. CH₄ is produced during serpentinization according to the Fisher Tropsch reaction (Charlou et al., 1991). Many ultramafic rock assemblages have been sampled on the MAR away from fracture zones, in particular by the Deep Sea Drilling Project. Changes of mechanical properties and of density of uplifted deep material in the accreting plate boundary zone caused by serpentinization may play an important role in the construction of slow-spreading ridges.

Broecker, W.S., and T.-H. Peng. Evaluation of the ¹³C constraint on the uptake of fossil fuel CO₂ by the ocean. Global Biogeochemical Cycles, 7(3):619-626 (1993).

The proposal by Quay et al. (1992) that the time histories of ¹³C in atmospheric CO₂ and oceanic SIGMA CO₂ provide a constraint on the magnitude of uptake of fossil fuel CO₂ by the ocean is examined. Our analysis suggests that, while the potential is there, the data base is too inaccurate to permit a distinction to be made among the carbon budgets currently on the table. Examples are given to demonstrate that the twenty or so percent uncertainties in the size of the effective exchange reservoir and in the magnitudes of the temporal changes in the ¹³C/¹²C ratio in atmospheric CO₂ and ocean SIGMA CO₂ are just too large to permit a reliable estimate of oceanic uptake of fossil fuel CO₂. We conclude that tracer-verified ocean general circulation models offer much better estimates than that based on the ¹³C budget.

Broecker, W.S., and T.-H. Peng. Greenhouse Puzzles. Eldigio Press, Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, 251 pp. (1993).

No abstract.

Broecker, W.S., and T.-H. Peng. Interhemispheric transport of carbon through the ocean. In The Global Carbon Cycle, M. Heimann (ed.). Springer-Verlag, Berlin, 551-570 (1993).

No abstract.

Broecker, W.S., and T.-H. Peng. What caused the glacial to interglacial CO₂ change? In The Global Carbon Cycle, M. Heimann (ed.). Springer-Verlag, Berlin, 95-115 (1993).

Scenarios put forward to explain the 80 µatm glacial to interglacial change in atmospheric CO₂ content are evaluated. The conclusion is that no single mechanism is adequate. Rather, contributions from temperature, sea ice, biological pumping, nutrient deepening, and CaCO₃ cycling must be called upon. The observation that the ¹³C/¹²C ratio for Antarctic foraminifera was 0.9 ± 1^o/_oo lower during glacial than during interglacial time constitutes a huge fly in the ointment for all scenarios proposed to date.

Broecker, W.S., Y. Lao, M. Klas, E. Clark, G. Bonani, S. Ivy, and T.-H. Peng. A search for an Early Holocene CaCO₃ preservation event. Paleoceanography, 8(3):333-339 (1993).

No abstract.

Broecker, W.S., G. Ostlund, S. Sutherland, T.-H. Peng, T. Takahashi, and W. Smethie. Radiocarbon Atlas, Volume I: Thermocline of the Atlantic Ocean. Lamont-Doherty Earth Observatory, Palisades, New York (1993).

No abstract.

Broecker, W.S., G. Ostlund, S. Sutherland, T.-H. Peng, T. Takahashi, and W. Smethie. Radiocarbon Atlas, Volume II: Thermoclines of the Pacific and Indian Oceans. Lamont-Doherty Earth Observatory, Palisades, New York (1993).

No abstract.

Brundrit, G., L. Krige, D.R. Palmer, J. Penrose, A. Forbes, and K. Metzger. Acoustic thermometry of ocean climate: Feasibility, Ascension-Cape Town. Proceedings, Second International Meetingon Global Acoustic Monitoring of the Ocean, Brest, France, June 20-22, 1993. Institut Francais de Recherche Pour l'Exploitation de la Mer (IFREMER), 8-10 (1993).

No abstract.

Cione, J.J., S. Raman, and L.J. Pietrafesa. The effect of Gulf Stream-induced baroclinicity on U.S. east coast winter cyclones. Monthly Weather Review, 121:421-430 (1993).

No abstract.

Clayton, T., P. Murphy, M.F. Lamb, F.J. Millero, R.H. Byrne, R.H. Wanninkhof, and R.A. Feely. The internal consistency of CO₂ measurements in the equatorial Pacific. Marine Chemistry, 44(2-4):269-280 (1993).

During a recent NOAA JGOFS equatorial Pacific cruise, all four analytical parameters of the carbonate system were measured: pH, total alkalinity (TA), total carbon dioxide (TCO₂), and the fugacity of carbon dioxide (fCO₂). The measurements made during leg 2 on surface waters have been used to examine the internal consistency of the carbon dioxide system in these waters. The internal consistency of the measurements was examined by using various inputs of the measured parameters (pH-TA, pH-TCO₂, pH-fCO₂, fCO₂-TCO₂, and TA-TCO₂) to calculate the components of the CO₂ system. The results indicate that the measurements have an internal consistency of ±0.003-0.006 in pH, ±5-7 µmol kg^-1 in TCO₂, and ±6-9 µAtm in fCO₂ if reliable constants are used for the dissociation of carbonic acid in seawater. These results indicate that our present understanding of the thermodynamics of the carbonate system in seawater is close to the present accuracy in measuring the various parameters of the system (±0.0002 in pH, ±4 µmol kg^-1 in TA, ±2 µmol kg^-1 in TCO₂, and ±2 µAtm in fCO₂).

Commons, D.N., J.R. Proni, H. Huang, W.P. Dammann, B.M. Goldenberg, J.G. Monsoon, and R.E. Fergen. Real world toxicity testing of an open ocean discharger. Proceedings, 66th Annual Conference and Expedition, Anaheim, CA, October 3-7, 1993. Water Environment Federation, 26 pp. (1993).

A study, called the Southeast Florida Outfall Experiment II (SEFLOE II), was conducted from February 1991 through August 1992 at four open ocean outfalls. The objective of the study was to assess the effect of the Florida Current and coastal oceanographic characteristics upon the surfacing effluent plumes. During the study, the results from laboratory bioassays on plant effluent samples were compared with results from bioassays on contemporaneous ocean dispersion plume samples. Acute bioassay species used were the mysid Mysidopsis bahia and the estuarine fish Menidia beryllina. The sea urchin Arbacia punctulata and the macroalga Champia parvula were the species used in short-term chronic bioassays during the SEFLOE II study. The results of this comparison indicate a disparity between exposure times and dilutions in laboratory bioassays, and those exposure times and dilutions actually demonstrated in the receiving waters.

DeMaria, M., and R.W. Jones. Optimization of a hurricane track forecast model with the adjoint model equations. Monthly Weather Review, 121(6):1730-1745 (1993).

The method of model fitting, or "adjoint method," is tested in a barotropic hurricane track forecast model. The model vorticity field at the beginning of an assimilation period is adjusted to minimize a cost function that is defined as the squared difference between the model vorticity and the vorticity from a sequence of analyses separated by 12 h. After the cost function is minimized, the model vortex closely follows the observed storm track during the assimilation period, indicating that information about the past track of the storm is being included in the model solution. Track forecasts using the assimilation procedure are compared with control forecasts where the model is initialized with a single analysis at the end of the assimilation period. Results from a series of 18 forecasts for Hurricane Hugo (1989) show that within a 12-h assimilation period the average track forecast errors are smaller than those of the control forecasts out to about 48 h. The forecast errors using a 24-h assimilation period are larger than the errors with a 12-h assimilation period. The method described by Derber in which a forcing term that minimizes the cost function is added to the vorticity equation is applied to extend the length of the assimilation period. The forcing function has very localized extrema in the vicinity of the vortex because the scale of the vortex is comparable with the distance that the vortex moves during the assimilation period. This localized forcing interferes with the subsequent motion of the storm during the forecast period. The magnitude of the localized forcing is reduced if the vorticity at the beginning of the assimilation period is first adjusted, and then the forcing term is added to further reduce the cost function. When the combined procedure is used, the average track errors are smaller than the errors in the control simulations out to 72 h. Forecasts from four additional storms from the 1989 Atlantic hurricane season are also presented. In two of these cases, the assimilation degrades the control forecasts. The degradation appears to be related to errors in the operational estimates of the storm positions and to poor first-guess fields used in the analyses.

DeMaria, M., and J. Kaplan. Verification of a statistical hurricane intensity prediction model. Preprints, 20th Conference on Hurricanes and Tropical Meteorology, San Antonio, TX, May 10-14, 1993. American Meteorological Society, Boston, 303-304 (1993).

No abstract.

DeMaria, M., J.J. Baik, and J. Kaplan. Upper-level eddy angular momentum fluxes and tropical cyclone intensity change. Journal of the Atmospheric Sciences, 50(8):1133-1147 (1993).

The eddy flux convergence of relative angular momentum (EFC) at 200 mb was calculated for the named tropical cyclones during the 1989-1991 Atlantic hurricane seasons (371 synoptic times). A period of enhanced EFC within 1500 km of the storm center occurred about every five days due to the interaction with upper-level troughs in the midlatitude westerlies or upper-level, cold lows in low latitudes. Twenty-six of the 32 storms had at least one period of enhanced EFC. In about one-third of the cases, the storm intensified just after the period of enhanced EFC. In most of the cases in which the storm did not intensify, the vertical shear increased, the storm moved over cold water, or the storm became extratropical just after the period of enhanced EFC. A statistically-significant relationship (at the 95% level) was found between the EFC within 600 km of the storm center and the intensity change during the next 48 h. However, this relationship could only be determined using a multiple regression technique that also accounted for the effects of vertical shear and sea surface temperature variations. The EFC was also examined for the ten storms from the 1989-1991 sample that had the largest intensification rates. Six of the ten periods of rapid intensification were associated with enhanced EFC. In the remaining four cases the storms were intensifying rapidly in a low-shear environment without any obvious interaction with upper-level troughs.

Dodge, P.P., M.L. Black, P.A. Leighton, B.A. Christoe, F.D. Marks, and R.W. Burpee. Time-lapse radar images of Hurricane Andrew's landfalls. Preprints, 20th Conference on Hurricanes and Tropical Meteorology, San Antonio, TX, May 10-14, 1993. American Meteorological Society, Boston, 163-166 (1993).

No abstract.

Dodge, P.P., and R.W. Burpee. Characteristics of rainbands, radar echoes, and lightning near the North Carolina coast during GALE. Monthly Weather Review, 121(7):1936-1955 (1993).

Characteristics of mesoscale rainbands and echoes in radar reflectivity data recorded during the field phase of the Genesis of Atlantic Lows Experiment (GALE) are presented. The primary sources of data were radar microfilm and manually-digitized radar (MDR) reports from the operational National Weather Service (NWS) radars at Cape Hatteras (HAT) and Wilmington (ILM), North Carolina. The data set also included cloud-to-ground lightning flashes that were recorded by the network operated by the State University of New York at Albany. The analyses included rainbands of at least 90-km length with lifetimes of at least 2 h. Nearly all of the rainbands were within 400 km of synoptic-scale or coastal fronts. Warm-sector rainbands predominated. Rainbands were classified by the location of their initial detection relative to the land, coastal shelf, and Gulf Stream. Rainbands were initially identified more frequently over the Gulf Stream and less often over the coastal shelf than the corresponding fractional areas monitored by the radars. Statistical tests determined significant differences in the sample means of the MDR and lightning data between the Gulf Stream and land regions that were largely a consequence of many more hours with MDR and lightning over the Gulf Stream. Composites relative to the beginning and ending of the rainband cases indicated that differences between the Gulf Stream and land were small shortly after the initial detection of rainbands and large just before the detection of rainbands. The largest Gulf Stream-land disparities occurred, on the average, during low-level cold and dry advection at HAT. Trunk and Bosart reported a convective echo maximum over the Gulf Stream near HAT and discussed physical processes that can account for the convective maximum. Analysis of one idealized distribution of convection, however, supports the likely role of sampling limitations of the NWS radar network in determining the location of the convective echo maximum near HAT.

Fine, R.A., E. Johns, and R.L. Molinari. Deep Western Boundary Current structure in the region of the Blake-Bahama outer ridge. Proceedings, Principal Investigators Meeting of the Atlantic Climate Change Program, Miami, FL, March 9-11, 1992. NOAA Climate and Global Change Program, Special Report No. 7, 137-142 (1993).

No abstract.

Franklin, J.L., S.J. Lord, S.E. Feuer, and F.D. Marks. Multi-scale objective kinematic analyses and the motion of Hurricane Gloria (1985). Preprints, 20th Conference on Hurricanes and Tropical Meteorology, San Antonio, TX, May 10-14, 1993. American Meteorological Society, Boston, 537-540 (1993).

No abstract.

Franklin, J.L., S.J. Lord, S.E. Feuer, and F.D. Marks. The kinematic structure of Hurricane Gloria (1985) determined from nested analyses of dropwindsonde and Doppler radar data. Monthly Weather Review, 121(9):2433-2451 (1993).

A set of three-dimensional, filtered, multiple-nested objective analyses has been completed for the wind field of Hurricane Gloria for 0000 UTC 25 September 1985. At this time Gloria was one of the most intense hurricanes ever observed in the Atlantic basin, with a minimum sea level pressure of 919 mb. The nested analyses, based on observations from airborne Doppler radar and Omega dropwindsondes, simultaneously describe eyewall and synoptic-scale features, and are the most comprehensive analyses of a single hurricane constructed to date. The analyses have been used to document the multiscale kinematic structure of Gloria and to investigate the relationship between the kinematic fields and the motion of the vortex. The analyses indicate that the vortex was unusually barotropic. The radius of maximum wind (RMW) was nearly vertical below 500 mb, with a slight inward slope with heights between 750 and 550 mb. The strongest azimuthal mean tangential winds were found well above the boundary layer, near 550 mb, where the RMW was smallest. We speculate that this unusual structure was associated with a concentric eye cycle. A persistent asymmetry in the distribution of eyewall convection was associated with the vertical shear of the environmental flow. The vortex moved approximately 2.5 m s^-1 faster than the deep layer mean flow averaged at 667 km radius from the center. Barotropic models have predicted a relationship between the relative motion of the vortex and the gradients of absolute vorticity in the cyclone's environment; however, the predicted relationship was not found in Gloria. The vortex also did not move with the mean flow in the immediate vicinity of the center; the motion of the hurricane was most consistent with the 300-850 mb layer mean flow well outside the eyewall, at a radius of 65 km. The analyses suggest that the environmental flow near the center had been distorted by eyewall convection, with the scale of the distortion determined by the local Rossby radius of deformation.

Gamache, J.F. The angular momentum of the hurricane inner core as observed by airborne Doppler radar. Preprints, 20th Conference on Hurricanes and Tropical Meteorology, San Antonio, TX, May 10-14, 1993. American Meteorological Society, Boston, 533-536 (1993).

No abstract.

Gamache, J.F. The effect of global positioning satellites upon the accuracy of dual-aircraft Doppler observations. Preprints, 26th International Conference on Radar Meteorology, Norman, OK, May 24-28, 1993. American Meteorological Society, Boston, 402-403 (1993).

No abstract.

Gamache, J.F., R.A. Houze, and F.D. Marks. Dual-aircraft investigation of the inner core of Hurricane Norbert. Part III: Water budget. Journal of the Atmospheric Sciences, 50(19):3221-3243 (1993).

The hydrometeor water budget of Hurricane Norbert on 24 September 1984 is computed using two microphysical retrieval techniques. Three-dimensional distributions of condensation, evaporation, precipitation, and advection of cloud and precipitation are computed, and a bulk water budget is computed as the volume integral of these distributions. The role of the microphysical retrievals is to provide the three-dimensional distribution of cloud water content, since it cannot be determined with the equipment available. Both retrieval methods use the steady-state continuity equation for water. The first method determines precipitation formation mechanisms from the radar-reflectivity and Doppler wind fields. The cloud water content is determined, through microphysical modeling, to be the amount necessary to explain the rate of precipitation formation. The second method (that of Hauser et al.) solves the water continuity equations as a boundary value problem, while also employing microphysical modeling. This method is applied in three dimensions for the first time. Asymmetries in the water budget of Hurricane Norbert were important, apparently accounting for nearly half of the net condensation. The most condensation and heaviest precipitation was to the left of the storm track, while the strongest evaporation was to the rear of the storm. Many of the downdrafts were unsaturated because they were downwind of the precipitation maximum where little water was available for evaporation. Since evaporation in the downdrafts was significantly less than the condensation in their counterpart updrafts, net condensation (bulk condensation-bulk evaporation) was significantly greater than would be implied by the net upward mass flux. Much of the vapor required to account for the greater bulk condensation appears to have come from enhanced sea surface evaporation under the dry downdraft air to the right of the storm track. The net outflow of condensate from the storm inner core was quite small, although there were appreciable outward and inward horizontal fluxes at certain locations. A maximum of ice outflow to the left of the storm track in front of the storm corresponded well to the ice particle trajectories that Houze et al. suggested were feeding the stratiform precipitation found farther outward from the storm center.

Garzoli, S.L. Geostrophic velocity and transport variability in the Brazil-Malvinas Confluence. Deep-Sea Research, 40(7):1379-1403 (1993).

This paper presents the results from a study of the dynamics of the Brazil-Malvinas Confluence in the southwestern Atlantic based on data collected with an array of inverted echo sounders. Dynamic height series were obtained at 10 different sites for a period of 15 months. The data are analyzed in terms of dynamic height, geostrophic velocities, and transports. The large variability previously inferred from satellite observations is observed in the dynamic height field of the surface, relative to 100 m, and is attributed to changes in the latitude of separation, the meandering of the Confluence front towards the east, and eddy generation. The eddy circulation observed is both cyclonic and anticyclonic. These eddies are observed both between the southward edge of the Brazil Current and the northward edge of the Malvinas Current and superimposed to the main flows. The diameter of the eddies is two to three times the Rossby radius of deformation. The highest observed values of the geostrophic velocities (102 cm/s at 36.5°S and -61 to -62 cm/s at 37.6°S) are associated with the large shear in frontal situations. The northward penetration of the Malvinas Current occurs during 1988 and 1990 during the southern hemisphere winter. This is in agreement with results from a previous deployment, satellite observations, and model results. The Brazil Current transport is at 35.2°S and 36.5°S, -24 Sv towards the south and -20 Sv between 37.7°S and 38°S (reference 1000 m). The transport of the Brazil Current return at 35.2°S is of the same value as the southward flow: 24 Sv. For the Malvinas Current, the estimates indicate a northward transport of 5 Sv at 37.7°S (reference 1000 m). These values are considered as a lower limit. The array captured only about half the flow due to the location of the deployments, and only the baroclinic component. The transport should be at least doubled to compensate the value obtained for the Malvinas return flow at the same latitudes, -24 Sv.

Goldenberg, S.B., and L.J. Shapiro. Relationships between tropical climate and interannual variability of North Atlantic tropical cyclones. Preprints, 20th Conference on Hurricanes and Tropical Meteorology, San Antonio, TX, May 10-14, 1993. American Meteorological Society, Boston, 102-105 (1993).

No abstract.

Gray, W.M., and C.W. Landsea. Examples of the large modification in U.S. east coast hurricane spawned destruction by prior occurring west African rainfall conditions. ICSU/WMO International Symposium on Tropical Cyclone Disasters, October 12-16, 1992, Beijing, China. J. Lighthill, Z. Zhemin, G. Holland, and K. Emanuel (eds.), Peking University Press, 182-189 (1993).

This paper discusses the surprisingly strong prediction (by 1 August) relationship which exists between west African rainfall and U.S. hurricane spawned destruction along the U.S. east coast and peninsula Florida for the period 1950-1991. Ninety-eight percent of such damage occurs after this data. Over four-fifths of east coast hurricane-spawned damage occurs during the highest third rainfall years. The last quarter century western Sahel drought has caused a large reduction in U.S. east coast hurricane damage.

Gray, W.M., and C.W. Landsea. West African rainfall and Atlantic basin intense hurricane activity as proxy signals for Atlantic conveyor belt circulation strength. Preprints, 4th Symposium on Global Change, Anaheim, CA. American Meteorological Society, Boston (1993).

No abstract.

Gray, W.M., C.W. Landsea, P.W. Mielke, and K.J. Berry. Predicting Atlantic basin seasonal tropical cyclone activity by 1 August. Weather and Forecasting, 8(1):73-86 (1993).

More than 90% of all seasonal Atlantic tropical cyclone activity occurs after 1 August. A strong predictive potential exists that allows seasonal forecasts of Atlantic basin tropical cyclone activity to be issued by 1 August, prior to the start of the active portion of the hurricane season. Predictors include June-July meteorological information of the stratospheric quasi-biennial oscillation (QBO), west African rainfall, the El Niño-Southern Oscillation (ENSO), as well as sea level pressure anomalies (SLPA), and the upper-tropospheric zonal-wind anomalies (ZWA) in the Caribbean basin. Use of a combination of these global and regional predictors provides a basis for making cross-validated (jackknifed) 1 August hindcasts of subsequent Atlantic seasonal tropical cyclone activity that show substantial skill over climatology. This relationship is demonstrated in 41 years of hindcasts of the 1950-1990 seasons. It is possible to independently explain more than 60% of the year-to year variability associated with intense (category 3-4-5) hurricane activity. This is significant because over 70% of all United States tropical cyclone damage comes from intense hurricanes, and over 98% of intense hurricane activity occurs after 1 August. Empirical evidence suggests that least sum of absolute deviations (LAD) regression yields substantially more improved cross-validated results than an analogous procedure based on ordinary least sum of squared deviations (OLS) regression. This improvement surprisingly occurs even with the squared Pearson product-moment correlation coefficient for which one might anticipate OLS regression to yield better cross-validated results than LAD regression.

Gray, W.M., C.W. Landsea, P.W. Mielke, and K.J. Berry. Summary of author's seasonal Atlantic basin tropical cyclone activity predictions by 1 June and comparison with other forecast times of 1 December and 1 August. Preprints, 20th Conference on Hurricanes and Tropical Meteorology, San Antonio, TX, May 10-14, 1993. American Meteorological Society, Boston, 240-243 (1993).

No abstract.

Hallett, J., W. Hendricks, R.A. Black, C.P.R. Saunders, and I. Brooks. Aircraft observations of precipitation development and hydrometeor charge in Florida cumuli. Proceedings, Conference on Atmospheric Electricity, St. Louis, MO, October 4-8, 1993. American Meteorological Society, Boston, 785-790 (1993).

No abstract.

Hanson, K., and G.A. Maul. Analysis of temperature, precipitation, and sea level variability with concentration on Key West, Florida, for evidence of trace-gas induced climate change. In Climatic Change in the Intra-Americas Sea, G.A. Maul (ed.). Edward Arnold Publishers, London, 193-213 (1993).

Meteorological and sea level data for Key West, Florida, have been examined for evidence of changes during recent decades that may be attributed to increasing trace gases in the atmosphere. The 136-year air temperature record (1851-1986) gives the evidence that a slight warming has occurred, but there has been no appreciable change since 1950. However, there are questions of the reality of the warming because of the varied temperature-observing conditions over the period of record. The 101-year precipitation record (1886-1986) gives evidence that no significant change in precipitation has occurred during the period of record. In addition to Key West weather, sea level records from all 62 stations on file with the Permanent Service for Mean Sea Level that cover the Caribbean Sea, Gulf of Mexico, the Bahamas, and Bermuda have been examined for linear trends. Average (�1 standard deviation) sea level rise is 0.4 cm/yr (�0.6 cm/yr) for all stations (mean record length 20 years), and 0.3 cm/yr (�0.4 cm/yr) for those stations with records 10 years in length. A regional maximum +1.0 cm/yr is centered in the northwestern Gulf of Mexico, an area of subsidence. Regional minima (approximately -0.3 cm/yr) occur in the southwestern Gulf and in the Lesser Antilles, where there is diastrophism. Average sea level rise at Key West, a site of tectonic stability, is 0.22 cm/yr (�0.01 cm/yr) for the period 1913-1986. Key West sea level seems unrelated to local air temperature, barometric pressure, precipitation, and records of coral growth, but is significantly lower than normal during the year preceding a strong El Ni�o-Southern Oscillation event, and higher than normal during the event itself. There is no evidence for accelerated sea level rise at this site.

Houston, S.H., and M.D. Powell. Surface wind fields during Hurricane Bob's (1991) landfall in New England. Preprints, 20th Conference on Hurricanes and Tropical Meteorology, San Antonio, TX, May 10-14, 1993. American Meteorological Society, Boston, 139-142 (1993).

No abstract.

Houston, S.H., F.D. Marks, and P.G. Black. A ship passes through Hurricane Andrew's eye. Mariners Weather Log, 37(1):64-69 (1993).

No abstract.

Jensen, R.E., S.H. Houston, C.L. Vincent, and M.D. Powell. Evaluation of a third generation wave model for the U.S. Atlantic coast. Proceedings, Second International Symposium on Ocean Wave Measurement and Analysis, New Orleans, LA, July 25-28, 1993. American Society of Civil Engineers, New York, 433-447 (1993).

No abstract.

Johns, E., and A.M. Wilburn. Hydrographic observations in the western tropical and subtropical North Atlantic Ocean: Atlantic Climate Change Program (ACCP) and Western Tropical Atlantic Experiment (WESTRAX) during 1990. NOAA Data Report, ERL AOML-22 (PB93-184760), 108 pp. (1993).

Data collected during the 1990 Atlantic Climate Change Program and the Western Tropical Atlantic Experiment are presented. The goals of the programs were to increase the understanding of the roles of the regional circulation and ocean circulation in global climate. Salinity, ocean temperature as a function of depth, and other hydrographic data were collected from shipborne platforms.

Johns, E., and A.M. Wilburn. Hydrographic observations in the western tropical and subtropical North Atlantic Ocean: Atlantic Climate Change Program (ACCP) and Western Tropical Atlantic Experiment (WESTRAX) during 1991. NOAA Data Report, ERL AOML-23 (PB93-184778), 82 pp. (1993).

Data collected during the 1991 Atlantic Climate Change Program and the Western Tropical Atlantic Experiment are presented. The goals of the programs were to increase the understanding of the roles of regional circulation and ocean circulation in global climate. Salinity, ocean temperature as a function depth and other hydrographic data were collected from shipborne platforms.

Jones, R.W., and M. DeMaria. Further results of variational data assimilation with a barotropic hurricane track forecast model. Preprints, 20th Conference on Hurricanes and Tropical Meteorology, San Antonio, TX, May 10-14, 1993. American Meteorological Society, Boston, 333-336 (1993).

No abstract.

Kaplan, J., and W.M. Frank. The large-scale inflow-layer structure of Hurricane Frederic (1979). Monthly Weather Review, 121(1):3-20 (1993).

Aircraft rawinsonde, satellite, ship, and buoy data collected over a 40-h period were composited to analyze the inflow-layer structure of Hurricane Frederic (1979) within a radius of 10° latitude of the storm center. To improve the quality of the composite analyses, the low-level, cloud-motion winds (CMWs) employed in this study were assigned a level of best fit (LBF). A LBF was assigned to each CMW by determining the level at which the closest agreement existed between CMW and ground-truth wind data (e.g., rawinsonde, aircraft, ship, and buoy). The CMWs were then adjusted vertically to uniform analysis levels, combined with ground-truth wind data, and objectively analyzed. These objectively analyzed wind fields were used to obtain kinematically-derived fields of vorticity, divergence, and vertical velocity. An angular-momentum budget was also computed to obtain estimates of surface drag coefficients. The low-level CMWs in this study were found to have LBFs ranging from 300 to 4000 m. It was shown that judicious use of this knowledge leads to substantial improvements in the estimates of the radial flow, but relatively insignificant improvement in the estimates of the rotational component of the wind. These results suggest that the common practice of assigning all low-level CMWs in a tropical cyclone environment to a constant level of 900-950 mb (approximately 500-1000 m) is probably appropriate for computations that depend primarily upon the rotational wind component. These findings, however, also indicate that failure to account for variations in LBFs of low-level CMWs could result in substantial errors in calculations that are sensitive to the radial wind. The kinematic analyses showed that the asymmetric wind structure observed previously in studies of Frederic's inner core extends out to at least 10° latitude radius. Frederic was characterized by strong northeast-southwest radial flow through the storm and a pronounced northwest-southeast asymmetry of the tangential wind field at each analysis level. Analysis of Frederic's surface 560 m angular-momentum budget showed that the mean value of the surface drag coefficient beyond 2° radius was approximately 1.8 × 10^-3.

Keene, W.C., J.R. Maben, A.A.P. Pszenny, and J.N. Galloway. Measurement technique for inorganic chlorine gases in the marine boundary layer. Environmental Science and Technology, 27(5):866-874 (1993).

A technique was developed to measure inorganic Cl gases in the marine boundary layer. The inlet inertially removed coarse aerosol (>1 µm diameter), and an in-line filter removed fine aerosol. A trace gas concentrator positioned downstream incorporated an acidic mist chamber which sampled HCl* (including HCl, NOCl, ClNO₂, and ClNO₃), followed by an alkaline mist chamber which sampled Cl₂* (including Cl₂ and a portion of HOCl). Mist solutions were analyzed by ion chromatography. Estimated detection limits for HCl* and Cl₂* were 39 and 13 pptv, respectively. Standard additions of calibration gases from permeation sources to ambient air were recovered quantitatively within source uncertainties. The sampler appears to discriminate against organic Cl gases. HCl* in coastal air near Miami varied from <39 to 268 pptv with lower mixing ratios at night. Ambient Cl₂ varied from >13 to 127 pptv with highest mixing ratios before dawn.

Keene, W.C., D.J. Jacob, A.A.P. Pszenny, R.A. Duce, J.J. Schultz-Tokos, and J.N. Galloway. Comment on "Aqueous phase chemical processes in deliquescent sea-salt aerosols: A mechanism that couples the atmospheric cycles of S and sea salt" by W.L. Chameides and A.W. Stelson. Journal of Geophysical Research, 98(D5):9047-9049 (1993).

Keene et al. (1990) measured substantial Cl deficits relative to sea salt in coarse aerosol sampled over the North Atlantic Ocean. These deficits were not balanced by NO₃ or non-sea-salt (nnss) SO₂/₄ in the aerosol and thus could not be explained completely by acid-displacement reactions (Brimblecombe and Clegg, 1988) or by reactions involving nonacidic N gases (Finlayson-Pitts et al., 1989). To account for the unexplained Cl-deficits, Keene et al. (1990) adopted from Behnke and Zetzsch (1989a,b) a stoichiometric description of the action of O₃ on sea-salt aerosol to produce Cl₂. They then developed and assessed a model for Cl cycling in the gas phase. The quality of the Keene et al. (1990) data and the validity of their interpretation have been questioned by Chameides and Stelson (1992) who report not significant Cl volatilization in photochemical model simulations of deliquescent sea-salt aerosol in the marine boundary layer (MBL). We wish to comment on some aspects of the Chameides and Stelson (1992) analysis in light of our previous work and that of others. Our comments focuses on the quality of the Keene et al. (1990) data and on mechanisms of Cl volatilization from sea-salt aerosol.

Lalou, C., J.-L. Reyss, E. Brichet, M. Arnold, G. Thompson, Y. Fouquet, and P.A. Rona. New age data for Mid-Atlantic Ridge hydrothermal sites: TAG and Snake Pit chronology revisited. Journal of Geophysical Research, 98(B6):9705-9713 (1993).

The chronologies of TAG and Snake Pit hydrothermal fields have been established using ²¹⁰Pb/Pb, ²³⁰Th/²³⁴U and ¹⁴C dating. At the TAG field, a Mn-oxide record, indicative of low temperature events, began at least 125,000 years and possibly 140,000 years ago with maximum intensities at 15,000, 7,000 and 4,000 years before present. High-temperature events, giving rise to sulfide deposits, began about 100,000 years ago and have been intermittent to the present day. A presently active site has experienced intermittent pulses of activity every 4,000 to 6,000 years over the past 20,000 years. Decrease in activity is often marked by low temperature aragonite precipitation in chimney conduits at 4,000, 7,000 and 9,000 years ago. After a period of quiescence lasting about 4,000 years, this site was reactivated about 50 years ago. The Snake Pit field is much younger, and no sulfides older than 4,000 years have been recovered. Relict sulfide deposits are dated between 2,000 and 4,000 years old, indicating this site was active during a quiescent period at TAG. Reactivation of Snake Pit took place about 80 years ago, and is presently concurrent with that of TAG. Comparison with hydrothermal sites on the East Pacific Rise suggests that on slow-spreading ridges the major fracture systems focusing the hydrothermal discharge can be reactivated at intervals and new deposits precipitated on top of older ones, while on faster-spreading ridges each pulse of activity is separated in space and time resulting in discrete deposits.

Lamb, M.F., R.A. Feely, L.D. Moore, and D.K. Atwood. Total CO₂ and nitrate measurements in the southwest Pacific during austral autumn (1990). NOAA Data Report, ERL PMEL-42 (PB93-188415), 68 pp. (1993).

During austral autumn of 1990, total CO₂ and nitrate measurements were made in the South Pacific as part of the Climate and Global Change (C&GC) program. Data were collected during two legs. Sampling for Leg 1 began along 170°W from 15°S to 60°S, then angled northwest toward New Zealand across the Western Boundary Current. Leg 2 included a reoccupation of some stations between 30°S and 15°S on 170°W, and measurements from 15°S to 5°N along 170°W. Ancillary measurements of salinity were also taken. Descriptions of sampling and methods and data summaries are given in this report.

Landsea, C.W. A climatology of intense (or major) Atlantic hurricanes. Monthly Weather Review, 121(6):1703-1713 (1993).

The variability of intense (or major) hurricanes in the Atlantic basin is investigated on both intraseasonal and interannual time scales. Differences are highlighted in characteristics between intense hurricanes and the weaker minor hurricanes and tropical storms. Intense hurricanes show a much more peaked annual cycle than do weaker tropical cyclones. Ninety-five percent of all intense hurricane activity occurrs during August to October. In addition, over 80% of all intense hurricanes originate from African easterly waves, a much higher proportion than is observed for weaker cyclones. Of all classes of Atlantic basin tropical cyclones, the intense hurricanes display the greatest year-to-year variability. The incidence of intense hurricanes also has decreased during the last two decades. A small portion of this decreased activity appears to be due to an overestimation of hurricane intensity during the period spanning the 1940s through the 1960s. After adjusting for this bias, however, a substantial downward trend in intense hurricane activity during recent years is still apparent. Given that intense hurricanes are responsible for more than 70% of all destruction caused by tropical cyclones in the United States, an understanding is needed of the physical mechanisms for these observed variations of intense hurricane activity.

Landsea, C.W., W.M. Gray, P.W. Mielke, and K.J. Berry. Forecasting seasonal Sahelian rainfall by 1 December of the previous year. Proceedings, 18th Annual Climate Diagnostics Workshop, Boulder, CO. NOAA, 394-397 (1993).

No abstract.

Landsea, C.W., W.M. Gray, P.W. Mielke, and K.J. Berry. Predictability of seasonal Sahelian rainfall by 1 December of the previous year and 1 June of the current year. Preprints, 20th Conference on Hurricanes and Tropical Meteorology, San Antonio, TX, May 10-14, 1993. American Meteorological Society, Boston, 473-476 (1993).

No abstract.

Lee, T.N., W. Johns, R. Zantopp, and E. Johns. Moored measurement of the thermohaline circulation and meridional heat flux in the western subtropical Atlantic at 26.5°N. Proceedings, Principal Investigators Meeting of the Atlantic Climate Change Program, Miami, FL, March 9-11, 1992. NOAA Climate and Global Change Program, Special Report No. 7, 143-153 (1993).

No abstract.

Marks, F.D., D. Atlas, and P.T. Willis. Probability-matched reflectivity-rainfall relations for a hurricane from aircraft observations. Journal of Applied Meteorology, 32(6):1134-1141 (1993).

The probability-matching method (PMM) was used to determine the relation between the distribution of equivalent reflectivity Z_e measured by an airborne C-band radar and that for concurrently measured rain rate R by a disdrometer on the same aircraft in the eyewall and outer bands of Hurricane Anita in 1977. When the PMM is applied to the disdrometer population of Z's and R's, one finds that the Z-R relations differ significantly from those obtained by linear regression of their logarithms. Such regression relations are deceptive. When PMM is applied to the set of Z_e's and R's, we get a family of Z_e-R relations as a function of range which differ significantly from the traditional disdrometer-based Z-R relation for hurricanes by Jorgensen and Willis (JW). These new relations are approximate power laws with slope (exponent) which decrease with increasing range. At ranges less than 35 km the reflectivity in the eyewall exceeds that in the outer bands and is consistent with the expectation from the disdrometer-based relations. At greater ranges the converse is true due to beamwidth averaging over a broader beam and different vertical profiles of reflectivity in the eyewall and outer bands. We also devise a method to obtain an "effective zero range" Z_e-R relation. This differs from the JW relation by -8.2 dBZ and reflects an error in the radar calibration. This approach is a novel way to calibrate an airborne meteorological radar. The methods may be used with any type of rainstorm and provide a means of using airborne radar and disdrometer systems for air-truthing rainfall measurements from space.

Maul, G.A. Ecosystem and socioeconomic response to future climatic conditions in the marine and coastal regions of the Caribbean Sea, Gulf of Mexico, Bahamas, and the northeast coast of South America. Caribbean Environment Programme, CEP Technical Report No. 22, 43 pp. (1993).

Global climate change, and particularly the impact of human activities on Earth's biogeographic environment, is of enormous socioeconomic and ecological importance. It is the regional effect of global change, however, that weighs most heavily on individual lives because of the complexity of local response to a world-wide phenomenon. This report summarizes the opinion of a Task Team of 23 experts concerning the implications of climate change in the Intra-Americas Seas (Gulf of Mexico-Caribbean Sea-Bahamas-Bermuda-Guianas), of a global 1.5°C temperature and 20 cm sea level rise by the year 2025. For some ecosystems in the region, the effect of temperature rise is much more important than sea level rise, and vice versa for others; for some neither is important; for others both are important. Of the 14 ecosystems considered, the most heavily impacted are expected to be deltas and beaches, both because of sea level rise; neither are particularly vulnerable to a modest temperature rise. Estuaries, wetlands, lagoons and seagrass beds will all be moderately affected by both the 1.5°C and 20 cm scenarios. The other two very important ecosystems, mangroves and coral reefs, are expected to have a low-to-moderate vulnerability to climate change per se, but both are expected to experience extreme stress due to local anthropogenic activities such as deforestation, coastal development, runoff, overfishing, and tourism. Seven socioeconomic issues were also studied in the context of local response to global change; tourism and the influence of tropical storms are considered most important vis a vis levels of vulnerability. As with the ecosystems, some other socioeconomic issues are more affected by sea level rise (e.g., settlements and structures, and cultural heritage) than temperature rise (which mostly affects coastal zones, public health, and human migration). In addition to evaluating the effects of 1.5°C and 20 cm global rises, the Task Team discussed the potential local rates of temperature and sea level rise and found that for the Intra-Americas Sea, less climatic change is expected than for other areas of Earth, but that human population pressure will significantly stress the region's environment. Finally, we report on new computer-based, decision-making tools for evaluating the effects of climate change, tools that will give decision makers quantitative information upon which to base new policies for management.

Maul, G.A. Implications of future climate on the ecosystems and socio-economic structure in the marine and coastal regions of the Intra-Americas Sea. In Climatic Change in the Intra-Americas Sea, G.A. Maul (ed.). Edward Arnold Publishers, London, 3-28 (1993).

Maul, G.A., and S.R. Baig. Glossary of scientific terms. In Climatic Change in the Intra-Americas Sea, G.A. Maul (ed.). Edward Arnold Publishers, London, 369-381 (1993).

Scientists use terms that can make a treatise such as Climatic Change in the Intra-Americas Seas inaccessible to non-specialists and, in particular, to management and policy makers not trained in the natural sciences. To overcome this difficulty, this glossary of terms covering some aspects of oceanography, geodesy, meteorology, ecology, and climatology has been included. The terms and abbreviations selected for inclusion are mostly those that have appeared in the text; the meanings are meant to be scientific rather than legal. We have freely paraphrased many of the definitions from more recent sources (Baker et al., 1966; Bates and Jackson, 1980; NOAA, 1988) without explicit acknowledgment in order to minimize text, and we have also cross-referenced some of the older texts (Sverdrup et al., 1942; Mitchell, 1948; Huschke, 1959). The reader is referred to the several sources listed below for more information, but is cautioned that terms and meanings change with time (Maul, 1988). For the future, it is urged that a multi-lingual glossary be created for the region, one that includes more information on socio-economic and public health terms.

Maul, G.A., and M.H. Bushnell. The relation between acoustic travel time and dynamic height anomaly off Abaco Island, Bahamas, pp. 88-96. In Joint IAPSO-IOC Workshop on Sea Level Measurements and Quality Control, Paris, France, October 12-13, 1992, N.E. Spencer (ed.). Intergovernmental Oceanographic Commission, Workshop Report No. 81, 167 pp. (1993).

Inverted Echo Sounders (IESs) measure the round-trip acoustic travel time from the IES to the sea surface. These relatively inexpensive ocean-bottom-mounted instruments have been proposed for (a) monitoring long-term change at a specific site of a dynamical variable of interest (e.g., heat content, thermocline depth, dynamic height anomaly, etc.), (b) for open-sea calibrating of satellite altimeters, and (c) for studying the difference in sea level signals between a coastal tide gauge and that offshore. For the purpose of sea level variations, particularly at the centimeter level of accuracy, precise relations between the travel time and dynamic height anomaly must be obtained. The usual assumption is that there are constant linear regression coefficients between dynamic height anomaly and travel time. Based on 77 hydrocasts over the depth range 0-3000 db during 1984-1987 in the offing of Abaco Island, Bahamas, the regression coefficients between travel time and dynamic height have been found to vary systematically from month to month. If not accounted for, this can add �10 dynamic centimeters of additional uncertainty when applying IES data to problems of sea level variability.

Maul, G.A., and D.M. Martin. Sea level rise at Key West, Florida, 1846-1992: America's longest instrument record? Geophysical Research Letters, 20(18):1955-1959 (1993).

The continuous series of sea level at Key West, Florida, commenced in 1913, but we have discovered sporadic measurements that date back to 1846. From records at the U.S. Army Corps of Engineers and the U.S. Coast and Geodetic Survey, the sea level series has been connected to a Summary (common) Datum. Thus, a gappy record of monthly and annual mean heights (H[t]), perhaps the United States' longest series over San Francisco (ca. 1854) or New York (ca. 1856), can be tested to ascertain if the rise in relative sea level at this site is stationary. Applying first and second order least squares and two-phase regression analyses, we find that dH/dt is 0.19 � 0.01 cm/yr, and that d²H/dt² = [9.6 � 8.6] 10^-3 cm/yr²; the two-phase regression shows H[t] rising 0.15 � 0.03 cm/yr before ca. 1925 and 0.23 � 0.01 cm/yr afterwards. Neither the second-order regression coefficient nor d²H/dt² nor the two-phase calculation are significant above the 75% confidence level, but all three are weakly consistent with accelerated rise. For the epoch 1951-1987, Key West sea level, corrected for post-glacial rebound, is best explained by concurrent measurements of 0-1,000 db dynamic height anomaly change.

Maul, G.A., and F.M. Vukovich. The relationship between variations in the Gulf of Mexico Loop Current and Straits of Florida volume transport. Journal of Physical Oceanography, 23(5):785-796 (1993).

Twelve years of monthly mean positions of the northern boundary of the Loop Current in the eastern Gulf of Mexico from satellite and in-situ data have been compared with coincident 1977-1988 estimates of volume transport in the Straits of Florida in the "sub-seasonal" frequency band 15^-1 to 5^-1 cycles per month. Volume transport estimated from Cuba minus Florida sea level difference in this frequency band accounts for 69% of the variance in volume transport estimated from the Florida-Grand Bahama Island submarine cable. On average, the Loop Current has a dominant period of 11 months, whereas the volume transport is dominated by annual spectral energy; little significant coherence squared occurs between them. The maximum northward penetration of the Loop Current occurs on average in winter when the volume transport is a minimum, but this is an artifact of the sampling epoch. This negative relationship is most pronounced for 1979-1981 when transport is characterized as unimodal, but for 1984-1985 and 1987 the Loop Current and volume transport are more in phase, bimodal, and transport and position tend to have more semiannual energy. In this "sub-seasonal band," the volume transport undergoes a significant change in the phase of its annual cycle after 1985 as compared with 1977-1984. For the 12 years considered in this study, the ensemble correlation between monthly position of the Loop Current and volume transport is essentially zero.

Mayer, D.A., and R.H. Weisberg. A description of COADS surface meteorological fields and the implied Sverdrup transports for the Atlantic Ocean from 30°S to 60°N. Journal of Physical Oceanography, 23(10):2201-2221 (1993).

Using COADS data spanning 1947-1988, we describe the regional nature of the Atlantic Ocean wind-driven circulation between 30°S-60°N, and its annual and interannual variability. The Sverdrup stream function defines the circulation gyres. Our focus is on three central gyres: the northern hemisphere anticyclonic subtropical gyre, the cyclonic tropical gyre just north of the equator, and the clockwise equatorial gyre straddling the equator. This stream function, computed with constant drag coefficient and air density, compares favorably with that from other climatologies. In the Straits of Florida, differences between the annual cycle in Sverdrup transport and observations may be due to regional winds farther north. In the tropical gyre, the Sverdrup circulation argues against a continuous western boundary current transporting water from the equatorial region into the Caribbean in boreal winter. Instead, the interior Sverdrup circulation implies a southeastward flowing boundary current, bringing to question the mechanisms for the known inter-hemisphere and inter-gyre exchanges of heat and mass. A conceptual model is proposed involving two stages. First, the western boundary current closing the clockwise equatorial gyre is instrumental in storing heat and mass between the North Equatorial Countercurrent ridge and the North Equatorial Current trough in boreal summer. Transport farther north, across the tropical gyre and into the subtropical gyre, in boreal winter is then accomplished by Ekman transport, as the seasonal change in wind stress torque deepens the thermocline, thus allowing for vortex stretching and northward Sverdrup transport over the region of warmest waters. Once in the subtropical gyre, the Ekman transport continues to be northward despite the fact that the Sverdrup transport reverses to be southward. Annual and interannual variability is addressed by examining the spectrum of curl and its regional distribution. Outside the tropics and the Sargasso Sea, interannual exceeds annual variability by at least a factor of 1.5. A pentadal analysis in the subtropical gyre indicates that wind stress curl was not a major factor in the density structure differences reported between 1955-1959 and 1970-1974, and, hence, these require other explanations.

McCreary, J.P., P.K. Kundu, and R.L. Molinari. A numerical investigation of dynamics, thermodynamics, and mixed-layer processes in the Indian Ocean. Progress in Oceanography, 31(3):181-244 (1993).

A 2½-layer thermodynamic numerical model is used to study the dynamics, thermodynamics, and mixed-layer physics of the Indian Ocean circulation. A surface mixed layer of temperature T_m is imbedded in the upper layer of the model, and entrainment and detrainment in the mixed layer are determined by wind stirring and surface cooling. There is also detrainment w_d through the base of the upper layer that models subduction. Monthly climatological data, including air temperature T_a and specific humidity q_a, are used to force the model, and model sea surface temperature (SST), T_m, is used to determine the sensible and latent heat fluxes. With a few notable exceptions, our main run solution compares well with observed current and SST data; this is particularly true for T_m, which typically differs from observed SST by less than 0.5-1.0°C. Our analyses focus on three topics: the relative importance of remote versus local forcing, the thermodynamic processes that determine the model SST field, and the development of meridional circulation cells. There are a number of examples of remotely forced circulations in our main run. During the spring a northeastward countercurrent flows against the prevailing winds along the Somali coast north of 4°N, and from October through February a southwestward Somali Undercurrent is present from the tip of Somalia to 3°N; both of these flows result in part from forcing during the previous Southwest Monsoon. From March through May there is another southwestward Somali Undercurrent south of 7°N, generated primarily by the propagation of a Rossby wave from the west coast of India. The currents along the west coast of India are either strongly influenced or dominated by remote forcing from the Bay of Bengal throughout the year. A northeastward flow is well established along the east coast of India in March, long before the onset of the Southwest Monsoon; it is remotely forced either by upwelling favorable, alongshore winds elsewhere within the Bay of Bengal or by negative wind curl in the western Bay. Finally, the Agulhas Current is strengthened considerably in a solution that includes throughflow from the Pacific Ocean. To investigate the relative importance of thermodynamic processes, we carried out a series of test calculations with various terms dropped from the T_m equation. There is little effect of T_m when the sensible heat flux is set to zero, or when the solar radiation field is replaced by a spatially smoothed version. When temperature advection is deleted, T_m is most strongly affected near western boundaries since isotherms are no longer shifted there by the swift currents; the annual-mean, surface-heat-flux field Q is also changed, with Q becoming more positive (negative) to compensate for the absence of warm (cold) currents. Without entrainment cooling, T_m never cools during the summer in the intense upwelling regions in the northern ocean, and the annual-mean heat gain through the ocean surface (the area integral of Q over the basin) reverses to become a net heat loss. In individual tests without entrainment cooling, with T_a=T_m, and with q_a set to 80% of its saturated value q_s, model SST warms near the northern and southern boundaries during their respective winters by about 1°C, indicating that several processes contribute to wintertime cooling. The T_m field degrades considerably in a single test run with both T_a=T_m and q_a=0.8 q_s, so that one or the other of these external forcing fields is required to be able to simulate SST accurately. The annual-mean circulation has two meridional circulation cells. In the Tropical Cell, water subducts in the southern ocean, flows equatorward in the lower layer of the western-boundary current, and is entrained back into the upper layer in the open-ocean upwelling regions in the southern ocean. In the Cross-Equatorial Cell, the subducted water crosses the equator near the western boundary, where it is entrained in the regions of intense coastal upwelling in the northern ocean. The strength of the cells is directly related to the assumed magnitude of the subduction rate w_d, but their structure is not sensitive to the particular parameterization of w_d used.

McLeish, W.L., J.R. Proni, S.J. Stamates, J.F. Craynock, and W.P. Dammann. Nearshore current measurements for the SEFLOE II project, 1991-1992. NOAA Technical Memorandum, ERL AOML-75 (PB93-227676), 111 pp. (1993).

The 1989 Southeast Florida Outfall Experiment (SEFLOE) was performed to evaluate the dispersion and advection of wastewater from ocean outfalls along the southeast Florida coast. The results showed that more comprehensive current measurements were needed to interpret the wastewater dilution measurements, and SEFLOE II was scheduled to include the additional data collection. Continuous series of current measurements were obtained at four outfalls both to support other measurements being collected during intensive survey periods and to compile long-term statistics of the different characters of ocean currents at the outfalls. Current meters were installed at two depths on each mooring.

Millero, F.J., J.-Z. Zhang, K. Lee, and D.M. Campbell. Titration alkalinity of seawater. Marine Chemistry, 44:153-165 (1993).

The titration system is described that was used to measure the total alkalinity of seawater (TA) during the Joint Global Ocean Flux Study (JGOFS) sponsored by the National Oceanic and Atmospheric Administration (NOAA) in the equatorial Pacific. It consists of a piston titrator, a pH meter, and a glass thermostated cell. Since the new pH meters and titrators have RS232 interfaces, the system can be easily connected to a personal computer. The computer programs used to carry out the titration and to determine TA, pH_sw (pH on the seawater scale), and TCO₂ from the full titration curve are described. A typical titration takes 20 min and consists of 25 points. Six separate titration cells were calibrated to be used on three systems at sea. The reliability of the electrodes was examined by titrations of 0.7 m NaCl with HCl at a pH near 3 and using seawater buffers at a pH near 8. Although most electrodes did not have Nernstian behavior over the entire pH range, all gave precise values of TA for a given solution. The individual cells were calibrated using standard Na₂CO₃ and seawater standards prepared in our laboratory and Certified Reference Material (CRM) provided by Dickson. The cells gave reliable values of TA, but the values of pH_sw were low (0.02) and values of TCO₂ were high (20 µmol kg^-1) due to the non-Nernstian behavior of the electrodes at a pH near 8.0. If the slope determined from the buffers is used, the titrations yield reliable values of TA, TCO₂, and pH_sw. Measurements on Dickson standards with the three cells at sea indicate that the systems have a reproducibility of ± 2-4 µmol kg^-1 (fall) and 20 ± 6 µmol kg^-1 (spring) too high. This offset in TCO₂ is independent of depth and is due to the non-Nernstian behavior of the electrodes. The offset is not due to unknown protolytes.

Millero, F.J., R.H. Byrne, R.H. Wanninkhof, R.A. Feely, T. Clayton, P. Murphy, and M.F. Lamb. The internal consistency of CO₂ measurements in the equatorial Pacific. Marine Chemistry, 44(2-4):269-280 (1993).

During a recent NOAA JGOFS equatorial Pacific cruise all four analytical parameters of the carbonate system were measured: pH, total alkalinity (TA), total carbon dioxide (TCO₂), and the fugacity of carbon dioxide (fCO₂). The measurements made during leg 2 on surface waters have been used to examine the internal consistency of the carbon dioxide system in these waters. The internal consistency of the measurements was examined by using various inputs of the measured parameters (pH-TA, pH-TCO₂, pH-fCO₂, fCO₂-TA, fCO₂-TCO₂ and TA-TCO₂) to calculate the components of the CO₂ system. The results indicate that the measurements have an internal consistency of �0.003-0.006 in pH, �5-7 µmol kg^-1 in TA, �5-7 µmol kg^-1 in TCO₂ and �69 µAtm in fCO₂ if reliable constants are used for the dissociation of carbonic acid in seawater. These results indicate that our present understanding of the thermodynamics of the carbonate system in seawater is close to the present accuracy in measuring the various parameters of the system (�0.002 in pH, �4 µmol kg^-1 in TA, �2 µmol kg^-1 in TCO₂ and �2 µAtm in fCO₂).

Millero, F.J., J.-Z. Zhang, S. Fiol, S. Sotolongo, R.N. Roy, K. Lee, and S. Mane. The use of buffers to measure the pH of seawater. Marine Chemistry, 44:143-152 (1993).

The pH of seawater can be measured in the field using potentiometric and spectrophotometric methods. The use of pH standards or buffers is an important aspect of the calibration of both methods in a laboratory on a common concentration scale. The buffers can also be used to monitor the performance of pH meter and spectrophotometer during a cruise. A procedure is described for the determination of the pH of seawater, where the proton concentration is expressed as moles kg-H₂O^-1 using seawater buffers. The buffers are prepared in synthetic seawater in the laboratory by the methods outlined by Bates and coworkers. We have prepared four buffers (Bis, Tris, Morpholine, and 2-Amino-pyridine) that cover a pH range from 6.8 to 8.8. The EMF values of the buffers were measured with a H₂, Pt/AgCl, Ag electrode system after their preparation and bottling for use at sea. The measured EMF values were found to be in good agreement (± 0.05 mV) with the original measurements of Bates and coworkers from 0 to 45°C. The measured pH of these buffers are in good agreement (± 0.001 pH units) with the values calculated from the equations of Dickson on the total pH scale based on Bates et al. Studies are underway to access the long-term stability of these buffers. We have also used these buffers to calibrate systems used to make potentiometric and spectrophotometric measurements of pH on seawater relative to the H₂, Pt/Ag, AgCl electrode from 5 to 45°C.

Molinari, R.L., E. Johns, R. Raghunath, W.E. Johns, and R.J. Zantopp. The Deep Western Boundary Current from 29°N to the equator. Proceedings, Principal Investigators Meeting of the Atlantic Climate Change Program, Miami, FL, March 9-11, 1992. NOAA Climate and Global Change Program, Special Report No. 7, 155-156 (1993).

No abstract.

Murray, J.W., M.W. Leinen, R.A. Feely, J.R. Toggweiler, and R.H. Wanninkhof. Equatorial Pacific: A process study in the central equatorial Pacific. Oceanography, 5(3):134-143 (1993).

No abstract.

Napp, J.M., P.B. Ortner, D.V. Holliday, and R.E. Pieper. Biomass spectra Gulf Stream epizooplankton communities. Deep-Sea Research, Part I, 40(3):445-459 (1993).

Zooplankton biovolume data from a multi-frequency acoustic profiling system were used to construct biovolume-size spectra for the Gulf Stream and the southern California Bight. These spectra were linear through most, but not all, of the size range sampled (0.025-4.00 mm, ESR). Analysis of covariance was sometimes a useful tool to distinguish among spectra taken at different times and places. Difference spectra offered an alternative method of visualizing disparities between spectra. We compared our acoustically-derived spectra from the Gulf Stream with those obtained from other oceans with different samplers and those obtained in the same waters with a different sampler. The results indicate that differences attributable to sampler bias within the same system presently make it difficult, if not impossible, to interpret comparison from different samplers in different ecosystems.

Palmer, D.R. Tropical Atlantic network design considerations. Proceedings, Second International Meeting on Global Acoustic Monitoring of the Ocean, Brest, France, June 20-22, 1993. Institut Francais de Recherche Pour l'Exploitation de la Mer (IFREMER), 32-34 (1993).

No abstract.

Palmer, D.R., T.M. George, J.J. Wilson, L.D. Weiner, and J.A. Paisley. Reception at Ascension Island, South Atlantic, of the transmissions from the Heard Island Feasibility Test. NOAA Technical Memorandum, ERL AOML-73 (PB93-176261), 35 pp. (1993).

The objective of the Heard Island Feasibility Test was to ensonify the global ocean with a single source to determine the feasibility of acoustically measuring the extent of ocean warming. Underwater acoustic signals were transmitted from a ship in the southern Indian Ocean and monitored at listening stations throughout the world. At Ascension Island, about 9,200 km from the source ship, all transmissions from the Heard Island Feasibility Test were recorded on at least eight hydrophones and, for many transmissions, on 11 hydrophones. The depths of most of these hydrophones are near the depth of the sound channel axis but some are considerably deeper. All are bottom mounted. Signal-to-noise ratios were found to be surprisingly high. Averaged over the CW transmissions and in a 1 Hz band, signal-to-noise ratios for the axial hydrophones south of the island range from about 19 to 30 db, adjusted to a source level of 220 db (referenced to 1 µPa at 1 m). The average signal-to-noise ratio for a hydrophone at a depth approximately 0.8 km below the axis is about 16 db, suggesting acoustic energy was not restricted to a narrow interval in depth centered about the sound channel axis. The travel time of the earliest arrival was found to be about 1 h, 44 min, 17 s. A late, reverberative signal was observed for at least 22 min after termination of the direct signal. An unexpected combination of phase stability and amplitude variability was observed in the received signals. Continuing analysis of the Ascension data set is likely to provide considerable information about the characteristics of acoustic signals that have propagated global distances.

Peng, T.-H. Possible reduction of atmospheric CO₂ by iron fertilization in the Antaractic Ocean. In A Global Warming Forum: Scientific, Economic, and Legal Overview, R.A. Geyer (ed.). CRC Press, Boca Raton, 263-285 (1993).

No abstract.

Peng, T.-H., and T. Takahashi. Ocean uptake of carbon dioxide. In Heat Transfer in Turbulent Flows, R.A. Amano, R.H. Pletcher, S.A. Sherif, R.G. Watts, and A.N. Anand (eds.). American Society of Mechanical Engineers, 117-134 (1993).

Factors controlling the capacity of the ocean for taking up anthropogenic CO₂ include carbon chemistry, distribution of alkalinity, pCO₂ and total concentration of dissolved CO₂, sea-air pCO₂ difference, gas exchange rate across the sea-air interface, biological carbon pump, ocean water circulation and mixing, and dissolution of carbonate in deep sea sediments. A general review of these processes is given and models of ocean-atmosphere system based on our understanding of these regulating processes are used to estimate the magnitude of CO₂ uptake by the ocean. We conclude that the ocean can absorb up to 35% of the fossil fuel emission. Direct measurements show that 55% of CO₂ from fossil fuel burning remains in the atmosphere. The remaining 10% is not accounted for by atmospheric increases and ocean uptake. In addition, it is estimated that an amount equivalent to 30% of recent annual fossil fuel emissions is released into the atmosphere as a result of deforestation and farming. To balance global carbon budget, a sizable carbon sink besides the ocean is needed. Storage of carbon in terrestrial biosphere as a result of CO₂ fertilization is a potential candidate for such missing carbon sinks.

Peng, T.-H., E. Maier-Reimer, and W.S. Broecker. Distribution of ³²Si in the world ocean: Model compared to observation. Global Biogeochemical Cycles, 7(2):463-474 (1993).

Calculations of the ³²Si/SiO₂ ratio obtained in ocean models are compared with measurements of this ratio made as part of the GEOSECS program (Somayajulu et al., 1987, 1991). A major difference is found; while the models predict threefold to fivefold higher ratios in the deep Atlantic Ocean than in the deep Pacific and Indian Oceans, no such difference is seen in the measurements. This points to a flaw in the measurements. Our modeling results suggest that the most interesting application for this 120-year half-life cosmogenic isotope is as a monitor of upwelling. However, considering the expense and difficulty associated with ³²Si measurements, such studies may prove impractical.

Powell, M.D. Wind forecasting for yacht racing at the 1991 Pan American Games. Bulletin of the American Meteorological Society, 74(1):5-16 (1993).

The U.S. Sailing Team competed successfully at the 1991 Pan American Games despite having no previous experience with the sailing conditions off Havana, Cuba. One of the key factors in the team's success was meteorological support in the form of wind climate analysis; application of sea breeze forecasting typical of the south Florida area, modified by tropical weather systems; and effective preregatta briefing.

Powell, M.D. Wind measurement and archival under the automated surface observing system (ASOS): User concerns and opportunity for improvement. Bulletin of the American Meteorological Society, 74(4):615-623 (1993).

The National Weather Service, as a part of its modernization effort, is implementing the Automated Surface Observing System (ASOS). Much discussion has occurred about various aspects of ASOS versus the current system of manual and automated observations. Based upon a study of the ASOS specifications and an informal survey of potential ASOS wind data users, defects of the wind sampling and archival strategy chosen for ASOS are discussed in terms of their impact on various user groups. Limitations include: (1) hourly observation average periods that do not conform to international recommendations for wind reporting made by the World Meteorological Organization; (2) no regular archival of high-resolution data--potentially valuable research data are destroyed if not identified within a 12-h period; and (3) no emergency power for operation in severe weather conditions. An alternative sampling and archiving strategy is recommended that benefits a wider cross section of users, without detracting from aviation and forecast service requirements, at a cost of less than 1% of the original ASOS portion of the National Weather Service's modernization budget.

Powell, M.D., and S.H. Houston. Analysis of surface wind fields in Hurricane Andrew. Preprints, 7th National Conference on Wind Engineering, UCLA, CA, June 27-30, 1993. Wind Engineering Research Council, College Station, 523-532 (1993).

No abstract.

Powell, M.D., and S.H. Houston. Surface wind field analyses in Hurricane Andrew. Preprints, 20th Conference on Hurricanes and Tropical Meteorology, San Antonio, TX, May 10-14, 1993. American Meteorological Society, Boston, 58-61 (1993).

No abstract.

Powell, M.D., S.H. Houston, and T.A. Reinhold. Standardizing wind measurements for documentation of surface wind fields in Hurricane Andrew. Proceedings, Conference on Hurricanes of 1992, Miami, FL, December 1-3, 1993. American Society of Civil Engineers, New York, Volume VI, 1-13 (1993).

No abstract.

Price, J.F., M.O. Baringer, R.G. Lueck, G.C. Johnson, I. Ambar, G. Parilla, A. Cantos, M.A. Kennelly, and T.B. Sanford. The Mediterranean Outflow. Science, 259:1277-1282 (1993).

No abstract.

Proni, J.R., J.F. Craynock, and J.J. Tsai. Miami Harbor Dredge Material Disposal Project: Total suspended solids measurements. Contract Report, W81EWF-2-C228, U.S. Army Corps of Engineers, Jacksonville, FL, 72 pp. (1993).

No abstract.

Pszenny, A.A.P., C.J. Fischer, A. Mendez, and M.P. Zetwo. Direct comparison of cellulose and quartz fiber filters for sampling submicrometer aerosols in the marine boundary layer. Atmospheric Environment, 27A(2):281-284 (1993).

Paired high-volume aerosol samples of 20-60-h duration were collected using identical Sierra Model 235 cascade impactors during a July-September 1991 research cruise in the Atlantic Ocean. Whatman 41 cellulose fiber was used for the final filter in one impactor and a quartz fiber filter was used for the final filter in the other impactor during each of 17 sampling intervals. A paired t-test of measured non-seasalt sulfate (NSS) mass concentrations indicates that the retention efficiencies of the two materials for this primarily submicrometer species are indistinguishable under the conditions of our sampling. A paired t-test of ammonium concentrations indicates slightly higher concentrations on Whatman 41, suggesting, perhaps, a positive artifact due to sorption of ammonia vapor.

Pszenny, A.A.P., W.C. Keene, D.J. Jacob, S. Fan, J.R. Maben, M.P. Zetwo, M. Springer-Young, and J.N. Galloway. Evidence of inorganic chlorine gases other than hydrogen chlorine in marine surface air. Geophysical Research Letters, 20(8):699-702 (1993).

We report the first measurements of inorganic chlorine gases in the marine atmosphere using a new tandem mist chamber method. Surface air was sampled during four days including one diel cycle in January 1992, at Virginia Key, Florida. Concentrations of HCl* (including HCl, ClNO₃, ClNO₂, and NOCl) were in the range 40 to 268 pptv and concentrations of Cl₂* (including Cl₂ and any HOCl not trapped in the acidic mist chamber) were in the range <26 to 254 pptv Cl. Concentrations of Cl₂* increased during the night, and decreased after sunrise as HCl* concentrations increased by similar amounts. The measurements suggest an unknown source of either HOCl or Cl₂ to the marine atmosphere. Photochemical model calculations indicate that photolysis of the observed Cl2* would yield a chlorine atom (Cl•) concentration of order 10⁴-10⁵ cm^-3. Oxidation by Cl• would then represent a significant sink for alkanes and dimethylsulfide (DMS) in the marine boundary layer. The cycling of Cl• could provide either a source or a sink for O₃, depending on NO_x levels.

Rogers, R.F., and R.E. Davis. The effect of coastline curvature on the weakening of Atlantic tropical cylcones. International Journal of Climatology, 13, 287-299 (1993).

This study attempts to determine the relationship between the curvature of the coastline and the filling (increase in central pressure) of hurricanes and tropical storms by comparing both the rate of filling and the total filling for storms striking convex, concave, and linear coastlines. The USA and Mexican coastline was approximated by a subjective smoothing procedure, and the coastal curvature corresponding to each landfalling Atlantic tropical cyclone from 1900 to 1979 was measured and grouped into one of the three curvature categories. Storm-filling rates and total amounts of filling were determined before and after landfall by computing the change in wind speed for various Saffir-Simpson hurricane intensity categories. The averages of these variables within each strength and curvature grouping were compared in order to determine if they were statistically different. Storms were also compared in order to determine if stronger storms fill a greater total amount than weaker storms, regardless of the coastline's curvature. Concave coasts were found to be associated with storms filling both more rapidly and by a greater amount than convex coasts for weak hurricanes and strong tropical storms, and they were associated with storms that filled by a greater amount for hurricanes of moderate strength. This most likely results from the lower water-to-land ratios associated with storms striking concave coasts and the reduction in latent and sensible heat fluxes from the surface. Also, stronger storms were found to fill more rapidly and by a greater total amount than weaker storms, and storms striking the East Coast generally filled more rapidly and by a greater total amount than storms striking the Gulf Coast or Florida.

Rona, P.A. New directions in seafloor hydrothermal research. Proceedings, Workshop 1992 on Global Undersea Research Program, Yokosuka, Japan, September 2-4, 1992. Japan Marine Science and Technology Center (JAMSTEC), 117-120 (1993).

Ten years ago members of a pioneering research community of marine geologists, geophysicists, geochemists, and biologists met at a NATO Advanced Research Institute to assess the initial studies of seafloor hydrothermal systems (Rona et al., 1983). The prevailing view at that time (Edmond et al., 1979; Von Damm et al., 1983), based on preliminary investigations of newly discovered warm springs at the Galapagos spreading center (Corliss et al., 1979) and hot springs at latitude 21°N at the East Pacific Rise (RISE Project Group, 1980), was that black smoker-type venting was the predominant type of venting, that the composition of solutions venting as black smokers was uniform, and that these solutions had worldwide influence on ocean chemistry and mineralization. The components of a seafloor hydrothermal system are a large heat source in a permeable medium and a fluid. Since magmatic heat sources in fractured basalt as a permeable medium and seawater are present at seafloor spreading centers, it was initially reasoned that the chemistry of hydrothermal solutions produced by reaction of circulating seawater with basalt should be uniform. A prominent geochemist went so far as to say at the 1982 meeting that further studies of hot springs at seafloor spreading centers would be "stamp collecting."

Rona, P.A., and D.R. Palmer. Acoustic imaging beneath the sea. In Physics News in 1992, P.F. Schewe and B.P. Stein (eds.). American Institute of Physics, New York, 1-2 (1993).

No abstract.

Rona, P.A., and D.R. Palmer. Imaging plumes beneath the sea. Journal of the Acoustical Society of America, 93(1):569-570 (1993).

No abstract.

Rona, P.A., and S.D. Scott. A special issue on seafloor hydrothermal mineralization: New perspectives; preface. Economic Geology, 88(8):1935-1976 (1993).

Seafloor hydrothermal mineralization is a product of the exchange of heat and chemicals between the lithosphere and the oceans that is occurring along the global system of divergent plate boundaries (seafloor spreading centers) at mid-ocean ridges and behind volcanic island arcs, at the island arcs, and at intraplate volcanic centers. This exchange process has changed our concept of ocean basins within the past 15 years from passive sinks that only received material transported from land to active sources of matter and energy that significantly effect global chemical mass balances and budgets, the thermal regime of the Earth, adaptation of life forms based on a food net dependent on the Earth's internal chemical energy (chemosynthesis) rather than sunlight (photosynthesis), and the formation of mineral deposits. A number of papers have reviewed the chemical (Von Damm, 1990), thermal (Lowell, 1991), biological (Childress, 1992), and mineralization (Cronan, 1980; Bonatti, 1981; Rona, 1984, 1988; Morrison and Thompson, 1986; B�cker and Lange, 1987; Gross and MacLeod, 1987, Scott, 1992) aspects of the global seafloor hydrothermal exchange process, and the relation of the mineralization to ancient deposits (Franklin et al., 1981; Mitchell and Garson, 1981; Sawkins, 1984; Scott, 1985, 1987). The purpose of this special issue is to present a cross section of papers at the cutting edge of research on seafloor hydrothermal mineralization.

Rona, P.A., and G. Thompson. Introduction to Atlantic hydrothermal activity. Journal of Geophysical Research, 98(B6):9621-9623 (1993).

Seafloor hydrothermal research has advanced rapidly from local to global scope through a sequence of discoveries. Hydrothermal research at seafloor spreading centers began in the mid-1960s with the discovery of hot metalliferous brines and sediments ponded in deeps along the slow spreading (half rate 1 cm yr^-1) axis of the Red Sea (Charnock, 1964; Miller, 1964; Swallow and Crease, 1965; Miller et al., 1966; Hunt et al., 1967; Bischoff, 1969). At the same time, a hydrothermal metalliferous component was identified in sediments of the East Pacific Rise (Skornyakova, 1965; Arrhenius and Bonatti, 1965; Bostrom and Peterson, 1966). Geophysicists recognized that heat flow measurements at spreading centers could only be explained by convective cooling of the crust with circulating seawater (Elder, 1967; Lister, 1972). In 1972 and 1973, warm springs and low-temperature hydrothermal precipitates were discovered at the TAG hydrothermal field on the slow-spreading (half rate 1.2 cm yr^-1) Mid-Atlantic Ridge near 26°N (Rona, 1973; Rona and Scott, 1974; M.R. Scott et al., 1974; R.B. Scott et al., 1974; Rona et al., 1975). Warm springs and chemosynthetic vent biota were found in 1977 at the intermediate-spreading (half rate 3 cm yr^-1) Galapagos spreading center (Williams et al., 1974; Lonsdale, 1977; Corliss et al., 1979). The existence and composition of pure, high-temperature end-member hydrothermal solutions were predicted by extrapolation of the composition of the low-temperature Galapagos hydrothermal solutions that were mixed with seawater (Edmond et al., 1979). Inactive massive sulfide deposits that had been formed by high-temperature hot springs (CYAMEX Scientific Team, 1979) were found in 1978 at 21°N on the East Pacific Rise, which is spreading at an intermediate rate (half rate 3 cm yr^-1). Active high-temperature hot springs with the predicted end-member solutions were found in 1979 with the discovery of black smoker-type venting within kilometers of the previously discovered relict massive sulfide deposits at the East Pacific Rise 21°N site (RISE Project Group, 1980). In 1985, the first high-temperature black smoker-type venting with massive sulfides and vent biota in the Atlantic Ocean were discovered at the TAG hydrothermal field (Rona, 1985a,b; Rona et al., 1986) and at the Snake Pit hydrothermal field (Scientific Party, 1986) at 26°N and 23°N, respectively, on the Mid-Atlantic Ridge. Additional hydrothermal sites continue to be found at spreading centers in the northeast Pacific, the southeast Pacific, and the Indian Ocean, as well as in back arc basins of the western Pacific, all leading to recognition of seafloor hydrothermal activity as a global phenomenon (Rona, 1988). The basic hydrothermal process is similar at the different locations and consists of subseafloor circulation of seawater, driven convectively by magmatic heat sources at or near spreading centers and reaction of the heated seawater with permeable rocks of the crust and sometimes the upper mantle. However, significant differences in solution chemistry, heat transfer, mineralization, and biology are being found at the different sites. The 11 papers presented in this special section on Atlantic hydrothermal activity are part of the initial series of papers which define chemical, physical, and biological characteristics of hydrothermal systems based on detailed investigations at the TAG and Snake Pit hydrothermal sites. These investigations include the initial intensive dive series at Snake Pit (11 dives) by Deep Submergence Vehicle (DSV) Nautile in 1988 (Mevel et al., 1989); at TAG (16 dives) and Snake Pit (three dives) by DSV Alvin in 1990 (Mid-Atlantic Ridge Hydrothermal Research Team, 1990); and by the two MIR submersibles in the TAG area in 1988 (18 dives) (Zonenshain et al., 1989; Lisitsyn et al., 1989) and in 1991 (six dives) (see P.A. Rona et al., this issue). Earlier versions of most of the papers were presented orally in two sessions at the fall 1990 American Geophysical Union meeting (Rona and Thompson, 1990; Thompson and Rona, 1990).

Rona, P.A., Y.A. Bogdanov, E.G. Gurvich, N.A. Rimski-Korsakov, A.M. Sagalevich, M.D. Hannington, and G. Thompson. Relict hydrothermal mounds at the TAG hydrothermal field, Mid-Atlantic Ridge, 26°N, 45°W. Journal of Geophysical Research, 98(B6):9715-9730 (1993).

Two relict hydrothermal zones were delineated between water depths of 3,400 and 3,500 m at the lower part of the east wall of the rift valley of the Mid-Atlantic Ridge in the TAG hydrothermal field using a deep-towed, side-scan sonar tow and a camera-temperature tow along the northern 3 km of the wall, and a submersible transect. Named the North and MIR relict zones, they are located about 4 km and 2 km northeast, respectively, of the known active high-temperature sulfide mound between water depths of 3,625 and 3,670 m on the rift valley floor near the base of the east wall. The North zone extends about 2 km along the northern end of the lower east wall. The zone includes two moundlike features up to 30 m high by 200 m in diameter imaged by side-scan sonar within a 2-km-long line of discontinuous hydrothermal deposits comprising inactive toppled and standing chimneys, layered material, and patchy dark stains on sediment photographed by the camera-temperature tow. Several other moundlike features were imaged with the side-scan sonar outside of the photographic coverage. The MIR relict hydrothermal zone 2 km south of the North zone, named after the MIR submersible used to investigate it, consists of three subzones: (1) a 200-m-wide area of diverse types of hydrothermal materials exposed by normal faulting at its western margin; (2) a 400-m-wide by 700-m-long central area of discrete groups of toppled and standing inactive sulfide chimneys up to 25 m high on a substrate of red metalliferous sediment and carbonate lutite; spires sampled on the highest chimneys are composed of coarse-grained, recrystallized sulfides dominated by pyrite and chalcopyrite which contain the first primary, free gold grains (2-3 µm diameter) found at a hydrothermal site on a mid-ocean ridge; and (3) a 150-m-wide hummocky area of layered hydrothermal material with the appearance of low temperature precipitates and carbonate lutite with patchy dark stains at its eastern margin. The active sulfide mound, the North zone, and the MIR zone are each located on the fractured western margins of gentle, dome-shaped areas of pillow flows typically 500 m in diameter interpreted as summits of volcanic centers that may have supplied heat to drive adjacent hydrothermal activity. The distribution and size of the active and inactive hydrothermal zones of the TAG field, the chronology, and the characteristics of relict samples recovered indicate a history of at least 100 x 10³ years of high-temperature hydrothermal episodes with multiple overprint stages of mineralization accompanied by alteration.

Rona, P.A., M.D. Hannington, C.V. Raman, G. Thompson, M.K. Tivey, S.E. Humphris, C. Lalou, and S. Petersen. Active and relict seafloor hydrothermal mineralization at the TAG hydrothermal field, Mid-Atlantic Ridge. Economic Geology, 88(8):1989-2017 (1993).

The TAG hydrothermal field is a site of major active and inactive volcanic-hosted hydrothermal mineralization in the rift valley of the slow-spreading Mid-Atlantic Ridge at 26°N. The TAG field occupies an asymmetric area at least 5 km x 5 km of the floor and wall of the rift valley between water depths of 2300 and 4000 m situated between 2 and 8 km east of an axial high along the center of the spreading segment. The axial high is the principal locus of present magmatic intrusions. The TAG field contains three main areas of present and past hydrothermal activity: (1) an actively venting high-temperature sulfide mound 200 m in diameter by 35 m high at a water depth of 3670 m on the floor of the rift valley near the base of the east wall; (2) two former high-temperature vent areas known as the MIR zone and the ALVIN zone containing multiple sulfide bodies that are undergoing deformation and mass wasting during uplift on fault blocks on the adjacent section of the lower east wall between water depths of 3400 m and 3600 m; and (3) a zone of low-temperature venting and precipitation of Fe- and Mn-oxide deposits farther from the axial high and higher on the east wall between water depths of 2300 m and 3100 m. The active sulfide mound and the MIR and ALVIN zones are situated near the margins of discrete volcanic centers. The volcanic centers occur at the intersections between ridge axis-parallel normal faults and projected axis-transverse transfer faults. The intersections of these active fault systems may act as conduits both for magmatic intrusions from sources beneath the axial high that build the volcanic centers and for hydrothermal upwelling that taps the heat sources. Convective heat transfer from a central black smoker vent complex (365°C; calculated convective heat flux 225 � 25 x 10⁶W), white smoker vents (<300°C), and widespread diffuse flow predominate on the active sulfide mound. Values of conductive heat flow measured at the margins of the active mound and the MIR zone appear to vary inversely with distance from adjacent volcanic centers, supporting the inference that episodic intrusions at the centers have driven hydrothermal circulation at the hydrothermal zones. A low in magnetic intensity coincides with the entire TAG field. The low is modeled as the combined effect of alteration pipes beneath the high-temperature hydrothermal zones and thermal degmagnetization of a still hot but largely solid intrusion beneath the axial high. Radiometric dating of sulfide samples and manganese crusts in the hydrothermal zones and dating of sediments intercalated with pillow lava flows in the volcanic center adjacent to the active sulfide mound indicate multiple episodes of hydrothermal activity throughout the field driven by heat supplied by episodic intrusions over a period of at least 140 x 10³ yr. The sulfide deposits are built by juxtaposition and superposition during relatively long residence times near episodic axial heat sources counterbalanced by mass wasting in the tectonically active rift valley of the slow-spreading oceanic ridge. Hydrothermal reworking of a relict hydrothermal zone by high-temperature hydrothermal episodes has recrystallized sulfides and concentrated the first visible primary gold reported in a deposit at an oceanic ridge. Supergene reactions of older sulfides with seawater produces secondary gold enrichment. Preservation of the recrystallized sulfides is favored by silicification or an armoring of oxides.

Rosenthal, S.L. Variability of the south Florida mean annual surface air temperature during the last three decades. NOAA Technical Memorandum, ERL AOML-77 (PB94-130721), 53 pp. (1993).

The oberved mean annual surface air temperature at Miami International Airport (MIA) exceeded the 30-year (1961-1990) mean by 1.2 to 2.4 standard deviations between 1989 and 1992. This was the result of a warming trend that started in the late 1960s and accelerated sharply in the mid 1980s. Unfortunately, the MIA surface temperature data cannot be taken at face value. At times during these years, the site for measuring daily surface maximum and minimum temperature was poorly positioned. There was a significant relocation of the equipment in the late 1970s. There have been three important changes of instrumentation from the original liquid in glass extreme thermometers to a series of electronic hygrothermometers, culminating in the installation of the less than ideal HO-83 in 1985. To determine the impact of these activities, the MIA temperature data were compared with data obtained at Palm Beach International Airport (PBI) and Page Field at Fort Myers (FMY). The latter are the NWS first-order stations closest to MIA. Comparisons were also made with data from nearby cooperative (COOP) stations and with data from the FAA station at Fort Lauderdale International Airport (FLL). Comparisons were also made with precipitation data from MIA, PBI and FMY. At least part of the accelerated warming in the 1980s must be attributed to a general south Florida warming during these years. However, MIA and PBI warmed faster than their neighboring COOP stations during the late 1980s, indicating that some artificial warming resulted from the HO-83 installations. The MIA mean annual daily minimum temperatures show systematic fluctuations but not a statistically-significant, long-term trend. These temperatures show a sharp, temporally-local rise starting in the mid 1980s similar to the rise found in the maximum temperatures which, therefore, provides support for the contention that this warming event is, at least partially, a natural event since previous investigators found no bias in the HO-83 minimum temperature data. This conclusion is supported by the results of our precipitation analyses. The MIA and FLL maximum temperatures both showed a warming trend that started in the late 1980s, which lends support to the conclusion that this trend is natural. The analyses support the contention that the MIA mean annual daily minimum temperature warmed somewhat through the effects of nearby jumbo jet operations and parking lot construction during the early 1970s. However, comparisons with other stations indicate that a general natural warming process impacted south Florida during this period and that the warming of MIA's mean annual daily minimum temperature was not entirely a result of human activities. Regardless of the mechanisms that were responsible, the trend ended abruptly in the early 1970s and these temperatures thereafter fell to a new low point in the mid 1980s.

Shapiro, L.J., and S.B. Goldenberg. Intraseasonal oscillations over the Atlantic. Journal of Climate, 6(4):677-699 (1993).

Winds at low (near-surface) and 200-mb levels from National Hurricane Center objective analyses are used to elucidate the dynamics of the tropical and subtropical intraseasonal oscillations for the North Atlantic/northeast Pacific regions, including over the continents, for the years 1980-1989. The intraseasonal oscillations are broken into three bands, with long (50-85 day), intermediate (30-55 day), and short (13-29 day) periods. Winter and summer seasons are analyzed separately. A complex empirical orthogonal function technique is used to derive the dominant modes of intraseasonal variability over the region, including their propagation characteristics. Statistically-distinct modes of variability are found only during the winter and only for the long-period and short-period bands. The dominant mode of coupled 200-mb, low-level, long-period variability during winter has a dipole structure. It has a substantial equivalent barotropic component in the subtropics, as well as a baroclinic structure consistent with quasigeostrophic midlatitude systems. Negative outgoing longwave radiation anomalies tend to be in phase with a low-level convergence/upper-level divergence couplet, which lies approximately one-quarter wavelength to the east of the cyclonic vorticity centers. The long-period oscillations during 1981-1988 are dominated by three events, with periods between about 60 and 70 days. There is a negative correlation, explaining about 50% of the variance, between the magnitude of the mode and an index of El Niño based on sea surface temperatures in the eastern equatorial Pacific. The dominant modes of short-period variability during winter appear as zonally-oriented wave trains similar to those found by previous investigators of global-scale fluctuations. Rotation of the modes of 200-mb variability effectively separates them into their propagating and standing components. Approximately one-half of the variance in the meridional wind near teleconnection centers of action is found in the eastward propagating component. The dominant mode of coupled 200-mb/low-level variability propagates to the east, and has a vertical structure similar to that in the long-period band. It has a predominant period near 18 days.

Shapiro, L.J., and M.T. Montgomery. A three-dimensional balance theory for rapidly rotating vortices. Preprints, 20th Conference on Hurricanes and Tropical Meteorology, San Antonio, TX, May 10-14, 1993. American Meteorological Society, Boston, J45-47 (1993).

No abstract.

Shapiro, L.J., and M.T. Montgomery. A three-dimensional balance theory for rapidly rotating vortices. Journal of the Atmospheric Sciences, 50(19): 3322-3335 (1993).

A three-dimensional balance formulation for rapidly rotating vortices, such as hurricanes, is presented. The asymmetric balance (AB) theory represents a new mathematical framework for studying the slow evolution of rapidly rotating fluid systems. The AB theory is valid for large Rossby numbers; it makes no formal restriction on the magnitude of the divergence or vertical advection, which need not be small. The AB is an ordered expansion in the square of the ratio of orbital to inertial frequencies, the square of a local Rossby number. The approximation filters gravity and inertial waves from the system. Advantage is taken of the weak asymmetries near the vortex core as well as the tendency for low azimuthal wavenumber asymmetries to dominate. Linearization about a symmetric balanced vortex allows the three-dimensional asymmetric dynamics to be deduced properly. The AB formulation has a geopotential tendency equation with a three-dimensional elliptic operator. The AB system has a uniformly valid continuation to nonlinear quasigeostrophic theory in the environment. It includes the full inertial dynamics of the vortex core, and reduces to Eliassen's formulation for purely axisymmetric flow. It has a full set of conservation laws on fluid parcels analogous to those for primitive equations, including conservation of potential temperature, potential vorticity, three-dimensional vorticity, and energy. A weakly nonlinear extension of the formulation in the near-vortex region is presented. Appropriate physical applications for the AB system, as well as its limitations, are discussed.

Siegenthaler, U., and T.-H. Peng. Summary of workshop on radiocarbon distributions as a constraint for global carbon cycle modeling. In The Global Carbon Cycle, M. Heimann (ed.). Springer-Verlag, Berlin, 570-574 (1993).

No abstract.

Smith, S.M., J.N. McElroy, and G.L. Hitchcock. Chlorophyll-a and phaeopigment concentrations in the Mississippi River plume and adjacent shelf waters. NOAA Technical Memorandum, ERL AOML-74 (PB93-206407), 81 pp. (1993).

The objective of this research project was to characterize the temporal and spatial variability of phytoplankton biomass in the Mississippi River plume and adjacent Louisiana shelf waters. Concentrations of chlorophyll-a and phaeopigments were measured during three research cruises in this region as part of NOAA's Nutrient Enhanced Coastal Ocean Productivity (NECOP) program. The data include both surface and subsurface phytoplankton pigment distributions during July 1990, March 1991, and May 1992.

Snyder, R.L., W.C. Thacker, K. Hasselmann, S. Hasselmann, and G. Barzel. Implementation of an efficient scheme for calculating nonlinear transfer from wave-wave interactions. Journal of Geophysical Research, 98(C8):14,507-14,525 (1993).

Nonlinear transfer from wave-wave interactions is an important term in the action-balance equation governing the evolution of the surface-gravity-wave field. Computation of this term, however, has hitherto been so consuming of computer resources that its full representation has not been feasible in nonparametric two-dimensional computer models of this equation. This paper describes the implementation of a hybrid computational scheme, incorporating a simplification first proposed by Thacker into the EXACT-NL Boltzmann integration scheme of Hasselmann and Hasselmann. This hybrid scheme retains EXACT-NL's symmetry, precision, and two-stage structure, but, by transferring a spectrum-independent preintegration from the second stage to the first, dramatically accelerates the resulting second-stage computation, enabling a relatively efficient and precise determination of nonlinear transfer in two-dimensional wave models. Physically, this preintegration collects together in single hybrid interactions, multiple interactions belonging to identical spectral-band quadruplets. Thus, all possible interactions are represented, and these interactions are represented in a uniquely efficient manner consistent with the spectral representation. We compute the coefficients in the resulting second-stage hybrid sum by essentially sorting and pre-summing the coefficients generated by a piecewise-constant first-stage EXACT-NL computation, using a variant of EXACT-NL that replaces the gather-scatter operations with a simpler bin-assignment procedure and employs a somewhat simpler set of integration variables. By exploiting the natural scaling of the integrand and partially pre-summing prior to sorting, we are able to further improve the efficiency of this computation for the deep-water case and to refine its integration-grid resolution almost to convergence. In wave-model computations of nonlinear transfer, vectorization on the spatial grid points of the model and selective truncation of the hybrid sum potentially reduce the working computation time for a single model time step to well under one Cray Y-MP single-processor CPU second per hundred grid points, while preserving a remarkably faithful representation of the full transfer.

Tivey, M.A., P.A. Rona, and H. Schouten. Reduced crustal magnetization beneath the active sulfide mound, TAG hydrothermal field, Mid-Atlantic Ridge at 26&176;N. Earth and Planetary Science Letters, 115(1-4):101-115 (1993).

A detailed near-bottom magnetic field survey was carried out by the submersible Alvin over the actively venting mound located within the TAG (Trans-Atlantic Geotraverse) hydrothermal field on the Mid-Atlantic Ridge at 26°08'N, 44°49'W. Three-dimensional analysis of these data clearly shows a distinct zone of reduced magnetization directly beneath the active mound. This magnetization low is consistent with the highly altered upflow zone of a hydrothermal vent system that feeds the actively venting mound structure. In contrast, the sea surface magnetic anomaly is associated with a broad 2 x 8 km magnetization low elongated along the axis, that includes both the active and inactive mounds. The short wavelength (250 m), near-bottom magnetic anomaly over the active mound is far too small to produce the long-wavelength (8 km) sea surface magnetic anomaly at TAG, however, and even a collection of mounds with similar magnetic structure cannot produce the magnetic moment needed to generate the sea surface anomaly. Other hypotheses, including reversely-magnetized crust and structurally-thinned crust, could account for the sea surface anomaly but are considered unlikely. The existence of vigorous hydrothermal activity at TAG and the lack of microseismic activity in the TAG area suggests that thermal demagnetization is the prime contributor to the sea surface anomaly. The thermal halo associated with a largely solid but still hot intrusion would provide sufficient demagnetization on a kilometer scale to produce the long-wavelength sea surface anomaly. Pervasive alteration at depth would also be an important factor in the destruction of crustal magnetization and is the only way that such a long wavelength magnetic signal could be preserved in the crust. The overall model of crustal magnetization at a hydrothermal field with discrete zones of demagnetization in the upper crust and a broader zone of demagnetization at depth is consistent with studies of hydrothermal systems in ophiolite suites. These studies show narrow alteration pipes in the upper crust feeding the exhalative seafloor deposits and pervasive alteration at depth which commonly have associated late-stage intrusive bodies. While detailed magnetic surveys may provide some clues to the location of oceanic hydrothermal upflow zones, only drilling will ultimately test these hypotheses.

Tsai, J.J., J.R. Proni, W.P. Dammann, and J.R. Craynock. Acoustic detection of particulates from dredged material discharges in the oceanic dredged material disposal site for the Calcasieu Bar Channel, Gulf of Mexico, August 19-29, 1991. Contract Report DWI-35-54001, U.S. Environmental Protection Agency, Narragansett, RI, 32 pp. (1993).

A study of the behavior of dredged material discharged in the Calcasieu Ocean Dredged Material Disposal Site using acoustical remote sensing techniques in combination with other measurement systems has provided substantial information on the dispersion and general behavior of such discharges. Information was obtained on discharged material plume structure, particulate transport, and water column residual. Features observed during the study include increasing plume width during the convective descent, possible bottom surges, and persistent near-bottom nepheloid layers. Residual water column dredged material concentrations were observed for times in excess of one hour and twenty minutes after discharge. Residual water column concentrations appear to diminish slowly and may persist for long periods of time. Determination of the general movement of water column residual material is made possible through use of the acoustic technique.

Velden, C., S. Nieman, S.D. Aberson, and J.L. Franklin. Tracking motions from satellite water vapor imagery: Quantitative applications to hurricane track forecasting. Preprints, 20th Conference on Hurricanes and Tropical Meteorology, San Antonio, TX, May 10-14, 1993. American Meteorological Society, Boston, 193-196 (1993).

No abstract.

Wakimoto, R.M., and P.G. Black. Damage survey of Hurricane Andrew and its relationship to the radar-detected eyewall. Preprints, 20th Conference on Hurricanes and Tropical Meteorology, San Antonio, TX, May 10-14, 1993. American Meteorological Society, Boston, 54-57 (1993).

No abstract.

Wanninkhof, R.H., and K. Thoning. Measurement of fugacity of CO₂ in surface water using continuous and discrete sampling methods. Marine Chemistry, 44(2-4):189-204 (1993).

Instrumentation and methodology is described which is used for measurement of the fugacity (or partial pressure) of carbon dioxide (fCO₂ or pCO₂) in surface seawater. Two separate instruments were developed for the measurements. One is an underway system which measures the mixing ratio of CO₂, XCO₂, in a headspace in equilibrium with surface seawater continuously pumped into a 24 l-equilibrium chamber. The other is a discrete system in which 460 ml aliquots of water areequilibrated with a 120 ml headspace. Both systems use a non-dispersive infrared analyzer as detector. In the underway instrument the average XCO₂ in the headspace of an equilibration chamber is measured at near in-situ temperature over 20 min each hour. At a cruising speed of 13 knots this translates into a space averaged fCO₂ value over 8 km. The underway system is ideally suited for mapping of the surface water fugacity over large geographic regions. Samples from the discrete instrument are analyzed at 20°C. The primary function of the system is for measurement of CO₂ and other (carbon) parameters sub-sampled from the same aliquot. To calculate the fCO₂ in water for in-situ conditions from the mixing ratio in the headspace of the flask of the discrete system, small carbon mass balance and, sometimes significant, temperature corrections have to be applied. Comparison of 100 surface values obtained in the South Atlantic using the underway and discrete systems shows that the average difference of pCO₂ values for the two systems ranges from -4.3 µatm to -8.6 µatm, depending on the temperature correction, with a standard deviation of 4 µatm. The differences show scatter of up the 15 µatm which we attribute to a mismatch between the point samples for the discrete system and the integrated samples for the underway system.

Wanninkhof, R.H., W.E. Asher, R. Weppernig, H. Chen, P. Schlosser, C. Langdon, and R. Sambrotto. Gas transfer experiment on Georges Bank using two volatile deliberate tracers. Journal of Geophysical Research, 98(C11):20,237-20,248 (1993).

A gas exchange experiment was performed on Georges Bank using the deliberate tracers sulfur hexafluoride (SF₆) and helium 3 (³He). The concentrations of the tracers were measured in the water column over a period of 10 days. During this time the patch grew from an 8-km-long injection streak to an area of about 500 km². The gas transfer velocity was determined from the change in the ratio of the tracers over time scaled to the ratio of their Schmidt numbers. A near-linear relationship between gas exchange and wind speed was observed based on four experimental points covering a wind speed range from 3 to 11 m/s. The results fall in the upper part of the range of gas transfer-wind speed relationships developed to date. Wind speeds during the experiment obtained from anemometers on the ship, on a free floating drifter, and on a fixed mooring showed significant differences. With the ability to measure gas transfer velocities over the ocean on time scales of several days, accurate wind speed/stress measurements are imperative to obtain a robust relationship between gas transfer and wind speed.

Washburn, L., M.S. Swenson, J.L. Largier, P.M. Kosro, and S.R. Ramp. Cross shelf sediment transport by an anticyclonic eddy off northern California. Science, 261(5128):1560-1564 (1993).

A combination of satellite imagery, shipboard profiles, drifter tracks, and moored current observations reveals that an anticyclonic eddy off the coast of northern California transported plumes of suspended sediments from the continental shelf into the deep ocean. The horizontal scale of the eddy was about 90 km, and the eddy remained over the continental shelf and slope for about two months during the summer of 1988. The total mass of sediments transported by the eddy was of order 100,000 metric tons. Mesoscale eddies are recurrent features in this region and occur frequently in eastern boundary currents. These results provide direct evidence that eddies export sediments from continental shelves.

Wilde, P., and P.A. Rona. 29th International Geological Congress, Kyoto, Japan, August 24-September 3, 1992. Scientific Information Bulletin, 18(2):95-105 (1993).

About 4,500 geologists and earth scientists from 85 countries, including large contingents from the Commonwealth of Independent States and the People's Republic of China, met in Japan for the 29th quadrennial meeting of the International Geological Congress. A major theme was the requirement of earth science involvement in identifying and handling not only resource needs but also in dealing with environment concerns for public interest. Both the end of the cold war, with its reunification of the global geological community, and the general acceptance of plate tectonics as the major terrestrial geological force made for a harmonious meeting more characterized by historical summaries and evidence of broadening international cooperation than by controversy or exciting new insights.

Willis, P.T., J. Hallett, W. Hendricks, and R.A. Black. Hydrometeor development and structure of a convective cell. Preprints, 20th Conference on Hurricanes and Tropical Meteorology, San Antonio, TX, May 10-14, 1993. American Meteorological Society, Boston, 74-77 (1993).

No abstract.

Willoughby, H.E. Nonlinear shallow-water vortex motion. Preprints, 20th Conference on Hurricanes and Tropical Meteorology, San Antonio, TX, May 10-14, 1993. American Meteorological Society, Boston, J38-40 (1993).

No abstract.

Wilson, W.D., W.E. Johns, M.D. Hendry, and J.A. Routt. Windward Islands Passages Monitoring Program: Physical oceanographic data collected on cruise WI-91-01, HMBS Trident, 15-21 December 1991. NOAA Technical Memorandum, ERL AOML-76 (PB94-129079), 62 pp. (1993).

During 1991, a collaborative program between the U.S. and Barbados was established with NOAA/CGC/ACCP support to conduct regular measurements of the transport and water mass characteristics in the major southern passages to the Caribbean. The program involves the use of a Barbados Coast Guard vessel (the HMBS Trident) that makes routine (monthly) patrols in this area, which has been equipped to collect standard hydrographic measurements (CTD and water samples) and velocity profiles measurements using a downward-looking ADCP. The purpose of the program is to determine the quantity and time-variability of South Atlantic surface, thermocline, and intermediate waters flowing into the North Atlantic in compensation for southward cross-equatorial transport of North Atlantic Deep Water, and to establish an economical means for future monitoring of this return flow. The report contains data from cruise WI-91-01 conducted December 15-21, 1991.

Zhang, J.-Z., and F.J. Millero. The chemistry of the anoxic waters in the Cariaco Trench. Deep-Sea Research, 40(5):1023-1041 (1993).

The Cariaco Trench has been widely used as a natural laboratory for the study of anaerobic processes since the deep waters were found to be anoxic in 1954. In the summer of 1990 on a cruise of the R.V. Thomas Washington, we had the opportunity to measure a number of chemical parameters (salinity, H₂S, O₂, pH, TCO₂, NH₄⁺, PO₄^3-, SiO₂, SO₃^2-, and S₂O₃^2-) in the eastern and western basins of the Cariaco Trench. The oxic-anoxic interface was located at 330 m in both basins. The concentrations of H₂S, NH₄⁺, PO₄^3-, and SiO₂ in the deep waters of the Cariaco Trench have increased with time. The linear extrapolations of H₂S and NH₄⁺ with time indicate that the trench was oxic around 1915. This turnover may be related to earthquakes that occurred in 1900 and 1929. The ratio of C/N/P/S in the anoxic waters was found to be close to 106:16:1:53, the ratio predicted from the oxidation of phytoplankton by sulfate. Micromolar concentrations of SO₃^2- and S₂O₃^2- were found below the interface in the intermediate waters. These intermediates appear to be due to the oxidation of H₂S by the sinking of oxygenated surface waters. The rates of oxidation of H₂S with oxygen also were measured in the Cariaco Trench waters at 25°C. Measurements were made on surface waters, deep waters, and mixtures of deep and surface waters. Oxidation rates were found to be 10 times faster in the deep waters than for surface seawater with added H₂S due to Fe²⁺ in the deep waters. The intermediates SO₃^2- and S₂O₃^2- formed during the oxidation of H₂S were also determined. A simple kinetic model was used to fit the results.

Zhang, J.-Z., and F.J. Millero. The products from the oxidation of H₂S in seawater. Geochimica et Cosmochimica Acta, 57:1705-1718 (1993).

The oxidation of sulfide in seawater is an overall second-order reaction, first-order with respect to both sulfide and oxygen. The major products formed from the oxidation of H₂S with O₂ have been measured in water and seawater as a function of pH (4-10), temperature (10-45°C), and salinity (0-36). The major products formed from the oxidation of H₂S were SO₃^2-, S₂O₃^2-, and SO₄^2-. The pH dependence of the product distribution has been attributed to the effect of pH on the rate of the individual reaction steps. A kinetic model was developed to account for the distribution of the reactants and products. The model is based on the following overall reactions:

H₂S + O₂ (k₁) --> Products (SO₃),

H₂SO₃ + O₂ (k₂ --> Products (SO₄), and

H₂S + H₂SO₃ + O₂ k₃ --> Products (S₂O₃).

Rate constants were determined for the oxidation of HS^- and formation of SO₃^2- (k₁), for the oxidation of SO₃^2- and production of SO₄^2- (k₂) and for the formation of S₂O₃^2- from HS^- and SO₃^2- (k₃). These values of k₁, k₂, and k₃ as a function of pH, temperature, and salinity can predict the concentrations of the measured reactants and products within experimental error. The effect of metals (Fe³⁺, Fe²⁺, Mn²⁺, Cu²⁺, and Pb²⁺) and oxides (alpha-FeOOH and MnO₂) on the product distribution has also been examined. The field measurements from the Framvaren Fjord (Norway) and Cariaco Trench (Venezuela) are in reasonable agreement with the laboratory results at the same concentration of Fe²⁺ as in the anoxic basins.

**1992**

Asher, W.E., P.J. Farley, R.H.Wanninkhof, E.C. Monahan, and T.S. Bates. Laboratory and field experiments on the correlation of fractional area whitecap coverage with air/sea gas transport. In Precipitation Scavenging and Atmosphere Surface Exchange, Volume 2, The Semonin Volume: Atmosphere Surface Exchange Processes, S.E. Schwartz and W.G.N. Slinn (eds.). Hemisphere Publishing Corporation, Washington, D.C., 815-828 (1992).

Laboratory results have demonstrated that bubble plumes are a very efficient air/water gas transport mechanism. Because breaking waves generate bubble plumes, it may be possible to correlate air/sea gas transport velocities with whitecap coverage. This correlation may then allow transport velocities to be predicted from measurements of apparent microwave brightness temperature through the increase in sea surface microwave emissivity associated with breaking waves. In order to develop this remote-sensing based method for predicting air/sea gas fluxes, the whitecap simulation tank at Battelle/Marine Sciences Laboratory was used to measure transport velocities for oxygen, helium, sulfur hexafluoride, and dimethyl sulfide. This allowed the gas exchange process to be studied as a function of fractional area bubble plume coverage, molecular diffusivity (or Schmidt number), and water temperature. Using these results, an empirical model has been developed that permits prediction of the transport velocity in the Whitecap Simulation Tank from bubble plume coverage and Schmidt number. The implications of these results to the analysis of in situ dual-tracer air/sea gas transport data are also discussed.

Atwood, D.K., J.C. Hendee, and A. Mendez. An assessment of global warming stress on Caribbean coral reef ecosystems. Bulletin of Marine Science, 51(1):118-130 (1992).

There is evidence that stress on coral reef ecosystems in the Caribbean region is increasing. Recently, numerous authors have stated that major stress results from "abnormally high" seasonal sea surface temperatures (SST) and have implicated global warming as a cause, stating that recent episodes of coral bleaching result therefrom. However, an analysis of available SST data sets shows no discernible warming trend that could cause an increase in coral bleaching. Given the lack of long-term records synoptic with observations of coral ecosystem health, there is insufficient evidence available to label temperatures observed in coincidence with recent regional bleaching events as "abnormally" high.

Black, M.L., and H.E. Willoughby. The concentric eyewall cycle of Hurricane Gilbert. Monthly Weather Review, 120(6):947-957 (1992).

Hurricane Gilbert of 1988 formed an outer eyewall as it intensified rapidly toward a record minimum pressure of 888 hPa in the western Caribbean. The outer eyewall strengthened and contracted, while the inner eyewall showed some signs of weakening before landfall on the Yucatan Peninsula. Remarkably, both eyewalls survived passage over land, but the storm was much weaker when it entered the Gulf of Mexico. Although the primary cause of weakening was passage over land, the effect of the contracting outer eyewall may have contributed. Later, the outer eyewall completely replaced the inner eyewall. Subsequently, it contracted steadily but slowly as Gilbert maintained nearly constant intensity over the cooler waters of the Gulf before final landfall on the mainland of Mexico.

Black, P.G., and A.V. Litinetski. Flight-level and surface wind observations in Hurricane Gilbert from AN-12 "Cyclone" and WP-3D "Orion" aircraft. Proceedings, 5th International Symposium on Tropical Meteorology, Obninsk, Russia, May 27-31, 1992. USSR State Committee on Hydrometeorology, 20-31 (1992).

No abstract.

Broecker, W.S., and T.-H. Peng. Interhemispheric transport of carbon dioxide by ocean circulation. Nature, 356:587-589 (1992).

Although anthropogenic emissions of carbon dioxide have today created a greater atmospheric CO₂ concentration in the Northern than in the Southern Hemisphere, a comparison of interhemispheric CO₂ profiles from 1980 and 1962 led Keeling and Heimann to conclude that, before the Industrial Revolution, natural CO₂ sources and sinks acted to set up a reverse (south to north) gradient which drove about one gigatonne of carbon each year through the atmosphere from the Southern to the Northern Hemisphere. At steady state, this flux must have been balanced by a counter flow of carbon from north to south through the ocean. Here we present a means to estimate this natural flux by a separation of oceanic carbon anomalies into those created by biogenic processes and those created by CO₂ exchange between the ocean and atmosphere. We find that before the Industrial Revolution, deep water formed in the northern Atlantic Ocean carried about 0.6 gigatonnes of carbon annually to the Southern Hemisphere, providing support for Keeling and Heimann's proposal. The existence of this oceanic carbon pump also raises questions about the need for a large terrestrial carbon sink in the Northern Hemisphere, as postulated by Tans et al. to balance the present global carbon budget.

Brown, B.E., W.A. Erb, and G.A. Maul. Intra-Americas Sea Marine Science Meeting of U.S. experts. NOAA Technical Memorandum, NMFS-SEFSC-308, 125 pp. (1992).

No abstract.

Brown, W.S., W.E. Johns, K.D. Leaman, J.P. McCreary, R.L. Molinari, P.L. Richardson, and C. Rooth. A Western Tropical Atlantic Experiment (WESTRAX). Oceanography, 5(1):73-77 (1992).

Recently, a group of researchers from the United States and the broader international community have developed coordinated plans for observational and modeling work in the western tropical Atlantic. The overall research program is referred to as WESTRAX, for Western Tropical Atlantic Experiment. This article summarizes the research plans of the various participants and the scientific issues that have motivated the studies.

Burpee, R.W., and P.P. Dodge. Analyses of visible satellite imagery of the south Florida sea breeze circulation. Preprints, 5th Conference on Mesoscale Processes, Atlanta, GA, January 5-10, 1992. American Meteorological Society, Boston, 77-80 (1992).

No abstract.

Craynock, J.F., W.L. McLeish, and J.R. Proni. Acoustical characterization of an effluent plume in the Charleston Harbor estuarine system. Contract Report, 91-0036866, Commissioners of Public Works of the City of Charleston, South Carolina, 22 pp. (1992).

A study of the effluent discharge from the City of Charleston Plum Island plant into the Ashley River/Charleston Harbor was carried out on January 14-15, 1992. Advanced acoustical methods, dye injection methods, and other advanced technologies were used in the study. The plumes originating from the risers of the outfall discharge line were observed to rise to the river surface while merging, such inter-plume merging beginning at about 2-3 m below the river surface. The plume dilution was about 17 to 1, i.e., plume dye concentration was about one-seventeenth the whole effluent dye concentration in the plant. Dye concentration measurements, made in the direction of current flow during a flood tide, indicated an effective dilution of about 50 to 1 at a distance of approximately 200 m from the discharge riser locations. Further up the river about 2-3 km from the discharge, at the Bascule Bridge and in the Wappoo Creek area, no dye was detected and acoustical reflectivity data indicated an absence of effluent material. Acoustical measurements were made in a direction downriver of the discharge point, where dyed plume material had not yet reached, and opposite to the direction of the ongoing flood tide. Effective dilutions ranging from 40 to 1 to 150 to 1 were observed in this region southeast of the discharge. The detection of two extraneous plumes, possibly natural springs, were made in the downriver portion of the study.

Dagg, M.J., and P.B. Ortner. Mesozooplankton grazing and the fate of carbon in the northern Gulf of Mexico. Proceedings, NECOP Workshop on Nutrient Enhanced Coastal Ocean Productivity, Chauvin, Louisiana, October 2-3, 1991. Texas A&M University Press, College Station, 117-121 (1992).

Grazing of the mesozooplankton community (organisms >200 µm) on phytoplankton was measured in two regions of the continental shelf west of the Mississippi River delta. Grazing by individual organisms was measured experimentally and scaled to the community by application of abundance and distribution data collected on several temporal and spatial scales by various methods. One of the principal fates of phytoplankton production stimulated by nutrient enrichment from the Mississippi River is to be grazed by the mesozooplankton community.

Davis, R.E., and R.F. Rogers. A synoptic climatology of severe storms in Virginia. The Professional Geographer, 44, 319-332 (1992).

A synoptic climatology is developed for Virginia using 21 years of late spring and summer surface and upper air observations. The climatology is produced by applying a combination of principal components analysis and cluster analysis such that each day is classified into one of a distinct number of synoptic situations. Days on which at least one severe storm occurred in Virginia are merged with the synoptic climatology. A majority of severe storms are associated with one synoptic situation distinguished by moderate instability and a high moisture content.

DeMaria, M., S.D. Aberson, K.V. Ooyama, and S.J. Lord. A nested spectral model for hurricane track forecasting. Monthly Weather Review, 120(8):1628-1643 (1992).

A numerical method for including a wide range of horizontal scales of motion is tested in a barotropic hurricane track forecast model. The numerical method uses cubic B-spline representations of variables on nested domains. The spline representation is used for the objective analysis of observations and the solution of the prediction equations (shallow-water equations on a Mercator projection). This analysis and forecasting system is referred to as VICBAR. The VICBAR model was tested in near real-time during the 1989 and 1990 Atlantic hurricane seasons. For the 1989 season, VICBAR had skill comparable with, or greater than, that of the operational track forecast models. For the 1990 season, VICBAR had skill comparable with that of the operational track forecast models, except at 72 h when QLM (a three-dimensional mesoscale model) had greater skill than VICBAR. During both 1989 and 1990, VICBAR had considerably more skill for forecasts of hurricanes than for forecasts of tropical storms. For the 1990 season, VICBAR was generalized to include time-dependent boundary conditions from a global forecast model. These boundary conditions improve the VICBAR forecasts, especially for the longer range forecasts (60-72 h). The skill of the VICBAR is sensitive to the choice of the background field used in the objective analysis and the fields used to apply the boundary conditions. The use of background fields and boundary condition fields from a 12 h old global model forecast significantly reduced the VICBAR skill relative to the use of fields from the current global forecast.

Eadie, B.J., J.A. Robbins, P. Blackwelder, S. Metz, J.H. Trefry, B. McKee, and T.A. Nelsen. A retrospective analysis of nutrient enhanced coastal ocean productivity in sediments from the Louisiana continental shelf. Proceedings, NECOP Workshop on Nutrient Enhanced Coastal Ocean Productivity, Chauvin, LA, October 2-3, 1991. Texas A&M University Press, College Station, 7-14 (1992).

Sediments have been collected and analyzed to obtain evidence in support of the argument that anthropogenic nutrient loading has led to changes in coastal water quality and increased productivity. Cores representing approximately 100 years of input show unmistakable signs of increased accumulation of organic carbon beginning early in the 1900s. Organic tracers show that virtually all of this increase appears to be of marine origin. At two sites within the plume/hypoxia region, preliminary estimates are that 50% to 70% more organic carbon is presently accumulating than at the turn of the century. These preliminary interpretations provide strong support for the central themes of the NECOP program. Analysis and interpretation of further supporting information is continuing.

Elsberry, R.L., G.J. Holland, H. Gerrish, M. DeMaria, C.P. Guard, and K. Emanuel. Is there any hope for tropical cyclone intensity prediction? -- A panel discussion. Bulletin of the American Meteorological Society, 73(3):264-275 (1992).

The outlook for tropical cyclone intensity forecasts from operational and research perspectives was discussed during a panel discussion at the 19th Conference on Hurricanes and Tropical Meteorology. Whereas the operational requirement at the National Hurricane Center is to predict maximum 1-min sustained wind speeds at specific locations, the research community is addressing the prediction of the maximum wind or minimum sea level pressure in the storm. Commonality was found in the forecast strategies for subjectively predicting storm intensity. The panelists suggested improvements may be gained from additional observations, better conceptual and theoretical models of storm structure and behavior, and enhancements in statistical and numerical models. The discussion period brought out opposing viewpoints on a number of topics. Both new observations and better use of the existing observations were believed to be necessary. The limitations and advantages of remotely sensed data for this problem were raised. The most vigorous debates were on the physical processes, such as existence or nonexistence of coupling between outer and inner core structure, and whether convection is simply a response to forcing or is an essential contributor to uncertainty in intensity forecasting. Several participants suggested that uncertainties related to the sea surface temperature and its evolution also contribute to the intensity forecast problem. Some specific suggestions for improving intensity forecasts are given in terms of new observations, new basic understandings, and new applied developments.

Enfield, D.B. Historical and prehistorical overview of El Niño/Southern Oscillation. In El Niño: Historical and Paleoclimatic Aspects of the Southern Oscillation, H.F. Diaz and V. Markgraf (eds.). Cambridge University Press, Cambridge, 95-117 (1992).

This paper presents a thumbnail sketch of what El Niño/Southern Oscillation (ENSO) is, how it may have existed (or not) in previous epochs, and its relation to paleoclimatic studies. El Niño is a recurrent aperiodic, interannual (2-5 years) warming of the tropical Pacific Ocean, with an associated atmospheric counterpart, the Southern Oscillation. The two synchronous phenomena appear to occur as the result of an unstable interaction between ocean and atmosphere and vacillate between two contrasting states. They are of very large spatial scale and involve remote interannual climatic perturbations beyond the equatorial Pacific region of intense interaction. These "teleconnections" are one of the primary ways in which El Niño-like fluctuations during historical and prehistorical epochs have been preserved in surrogate records by biospheric and geological processes. Analyses of historical, proxy, and geological information suggest that: (1) ENSO has existed intermittently, as today, over at least the last 5,000 years; and (2) its statistics are probably nonstationary during that period, although apparently not in relation to variations of the background climate, such as the Little Ice Age. Evidence as to the existence of ENSO prior to 5,000 BP is mainly geological and as yet equivocal. Strategies for paleoclimatic research in this area are discussed in regard to several possible scenarios.

Festa, J.F., and R.L. Molinari. An evaluation of the WOCE volunteer observing ship-XBT network in the Atlantic. Journal of Atmospheric and Oceanic Technology, 9(3):305-317 (1992).

A volunteer observing ship (VOS)-expendable bathythermograph (XBT) network has been proposed for the Atlantic Ocean to satisfy World Ocean Circulation Experiment (WOCE) objectives in the upper water column. These objectives include measuring changes in upper-layer temperature. An evaluation of the proposed WOCE XBT network to resolve variability in sea surface temperature (SST), temperature distribution at 150 m (T150), and average temperature of the upper 400 m (T400L) between 25°S and 35°N is performed. A sampling design study based on an optimum interpolation (OI) of the historical XBT data set is used to construct uncertainty distributions for various XBT networks. The OI technique requires statistical representations of the variability (in the form of structure functions) of the three variables that are derived from the historical database. The structure functions and various sampling grids are used to construct uncertainty maps. Two seasons are used in the analysis of SST. In both seasons, uncertainties in mapped SST values for the proposed WOCE grid range from 0.3°C to 0.4°C in regions of adequate data coverage. Errors are larger along the boundary. Uncertainties in the T150 fields are larger (0.5°-0.7°) because of the smaller scales of spatial variability at depth. Errors in T400L range from 0.3°C to 0.4°C. The effects of alternative observing strategies on the error maps are shown. Finally, error maps derived from the XBT network as it exists today (i.e., incomplete) are given. The maps indicate that monthly resolution is not available from the incomplete network.

Fiedler, P.C., F.P. Chavez, D.W. Behringer, and S.B. Reilly. Physical and biological effects of Los Ni�os in the eastern tropical Pacific, 1986-1989. Deep-Sea Research, Part A, 39(2):199-219 (1992).

The eastern tropical Pacific Ocean was surveyed in August-November 1986, 1987, 1988, and 1989 as part of a long-term program to monitor dolphin stocks. Temperature, salinity, chlorophyll, and nutrients were monitored to help interpret variability in dolphin stock estimates. The four surveys reveal major environmental changes during the moderate 1987 El Ni�o and the cold La Ni�a episode that followed in 1988. During the "onset" phase of El Ni�o in fall 1986, surface temperatures were up to 1.5°C above normal in equatorial water, but near normal in tropical water north of the equator. The equatorial thermocline ridge was deepened by 10-30 m. During the "mature" phase of El Ni�o in fall 1987, surface temperature anomalies were up to +2.5°C in equatorial water and about +1°C in tropical water. Thermocline topography was anomalously flat. Surface chlorophyll and nutrient concentrations declined by 11-48% compared to 1986, with the greatest declines occurring in coastal and equatorial upwelling systems and along the countercurrent thermocline ridge. During La Ni�a in 1988, equatorial surface temperatures were up to 2.5°C below normal and the equatorial thermocline ridge was 10-50 m shallower than normal. Chlorophyll and nitrate concentrations increased by 58-65% compared to 1987. In 1989, surface temperature was within �1°C of normal throughout the study area and chlorophyll concentrations were similar to those observed in 1986. Changes in nutrient availability and biological productivity during the El Ni�o/La Ni�a cycle were caused by variations in both the rate of wind-driven upwelling and in the nutrient content of subsurface water entrained by upwelling.

Franklin, J.L., and M. DeMaria. The impact of Omega dropwindsonde observations on barotropic hurricane track forecasts. Monthly Weather Review, 120(3):381-391 (1992).

A scarcity of observations in the hurricane environment is one factor believed to be limiting the improvement in hurricane track forecast accuracy. Since 1982, the Hurricane Research Division (HRD) of the NOAA Atlantic Oceanographic and Meteorological Laboratory has conducted 14 experiments to determine the wind and thermodynamic fields within about 1000 km of tropical cyclones in the Atlantic basin. During these synoptic-flow experiments, Omega dropwindsondes (ODWs) are released from the two NOAA WP-3D research aircraft over a 9-10 h period in the hurricane environment. The ODWs measure pressure, temperature, humidity, and wind as they descend from flight level (about 400 mb) to the surface. These data are then transmitted in real time to the National Hurricane Center (NHC) and the National Meteorological Center (NMC). Recently, a barotropic, nested, spectral hurricane track forecasting model, VICBAR, has been developed at HRD and tested quasi-operationally during the 1989 and 1990 hurricane seasons. Forecasts from this model have compared favorably with other models run at NHC and NMC. In this study, the VICBAR model is used to evaluate the impact of ODW data on track forecast error for the 14 HRD synoptic-flow experiments. The ODW data produced highly consistent reductions in track forecast errors in this sample of cases. Forecast improvements due to single-level midtropospheric (aircraft) data were significantly smaller than those due to the ODWs. At the important verification times of 24-36 h (prior to landfall), when the decision to issue a hurricane warning is being made, the ODWs reduced the model mean forecast error by 12%-16%. These improvements, statistically significant at the 99% level, are comparable to the total improvement in normalized NHC official 24 h forecast error occurring over the past 20-25 years.

Froelich, P.N., V. Blanc, R.A. Mortlock, S.N. Chillrud, W. Dunstan, A. Udomkit, and T.-H. Peng. River fluxes of dissolved silica to the ocean were higher during glacials: Ge/Si in diatoms, rivers, and oceans. Paleoceanography, 7(6):739-767 (1992).

Two centric marine diatom species, Thalassiosira oceanica and Thalassiosira antarctica, were grown in batch cultures to determine the incorporation of germanium (Ge) and silicon (Si) into siliceous shells (opal). The results were modeled as Ge/Si "isotope" fractionation. During exponential growth, diatoms take up and incorporate Ge/Si from solution without major discrimination against Ge. During stationary phase growth near silica limitation, the Antarctic species (T. antarctica) discriminates slightly against Ge but integrated (Ge/Si)_opal produced over the latter portion of the growth cycle is indistinguishable from the initial solution ratio. These results confirm experiments using radioactive ⁶⁸Ge that showed absence of fractionation during diatom silica uptake (Azam and Volcani, 1981), in contrast to two-box ocean models that invoke 50% Ge discrimination by diatoms to explain the observed "excess" surface ocean germanium concentration (Murnane and Stallard, 1988; Froelich et al., 1989) and late Pleistocene ocean sediment (Ge/Si)_opal records (Mortlock et al.,1991). Runs of a 10- box ocean Ge and Si model (PANDORA) with 50% discrimination reproduce the excess surface ocean Ge but introduces curvature into the deep ocean Ge versus Si relationship that is not observed in the oceans. Thus, 50% fractionation is not supported by either cultures or models. If diatoms do not fractionate Ge/Si, then late Pleistocene (Ge/Si)_opal variations in piston cores are caused not by changes in local biosiliceous production and silica utilization (Mortlock et al., 1991) but rather by whole ocean changes in (Ge/Si)_seawater. The marine (Ge/Si)_opal record of the last 450 kyr can be modeled as transient oceanic responses to instantaneous continental climate transitions of consistent with the chemical weathering model of Murnane and Stallard (1990). Glacial periods are characterized by lower continental weathering intensity, lower (Ge/Si)_riv, and two-fold higher dissolved silica river fluxes. Marine (Ge/Si)_opal records thus contain a history of ocean silica chemistry that reflect rapid global changes in continental weathering.

Galloway, J.N., J.E. Penner, C.S. Atherton, J.M. Prospero, H. Rodhe, R.S. Artz, Y.J. Balkanski, H.G. Bingemer, R.A. Brost, S. Burgermeister, G.R. Carmichael, J.S. Chang, R.J. Charlson, S. Cober, W.G. Ellis, Jr., C.J. Fischer, J.M. Hales, D.R. Hastie, T. Iversen, D.J. Jacob, K. John, J.E. Johnson, P.S. Kasibhatla, J. Langner, J. Lelieveld, H. Levy, III, R. Lipschultz, J.T. Merrill, A.F. Michaels, J.M. Miller, J.L. Moody, J. Pinto, A.A.P. Pszenny, P.A. Spiro, L. Tarrason, S.M. Turner, and D.M. Whelpdale. Sulfur and nitrogen levels in the North Atlantic Ocean's atmosphere: A synthesis of field and modeling results. Global Biogeochemical Cycles, 6(2):77-100 (1992).

In April 1990, 42 scientists from eight countries attended a workshop at the Bermuda Biological Station for Research to compare field measurements with model estimates of the distribution and cycling of sulfur and nitrogen species in the North Atlantic Ocean's atmosphere. Data sets on horizontal and vertical distributions of sulfur and nitrogen species and their rates of deposition were available from ships' tracks and island stations. These data were compared with estimates produced by several climatological and event models for two case studies: (1) sulfate surface distributions and deposition; and (2) nitrate surface distributions and deposition. Highlights of the conclusions of the case studies were that the measured concentrations and model results of nitrate and non-seasalt sulfate depositions appeared to be in good agreement at some locations but in poor agreement for some months at other locations. The case studies illustrated the need for the measurement and modeling communities to interact not only to compare results, but also to cooperate in improving the designs of the models and the field experiments.

Garraffo, Z., S.L. Garzoli, W. Haxby, and D.B. Olson. Analysis of a general circulation model. Part 2: Distribution of kinetic energy in the South Atlantic and Kuroshio/Oyashio systems. Journal of Geophysical Research, 97(C12):20,139-20,153 (1992).

The energy of the model transient eddies at 37.5 m is compared with GEOSAT altimeter observations for the South Atlantic Ocean and for the Kuroshio system. The model shows areas of transient motions overlapping the ones obtained from GEOSAT altimeter data. For the South Atlantic Ocean, the modeled eddy kinetic energy is smaller than the one observed with GEOSAT, by a factor of 3 for area average on the whole South Atlantic region, and by a factor of 4 for its western boundary. On the Agulhas system, transient eddy activity develops in the region where the Agulhas Current retroflects. In the western South Atlantic, the modeled eddy activity is concentrated on the Confluence front; observed variability along a more extended region following the topography is not resolved in the model. For the Kuroshio region, the energy level of the modeled transient motions is comparable with GEOSAT observations, but the model eddy activity is more concentrated in the Kuroshio Current and not in the Kuroshio extension. The observations show the opposite. For the South Atlantic Ocean, a comparison is also done between model eddy kinetic energy (defined as including standing and transient eddy contributions) with values obtained from surface driftnets. The analysis shows differences in the western boundary, and good agreement across the South Atlantic Ocean between 35°S and 45°S. In this formulation, the model mean energy level is smaller than that observed with drifters from the First GARP Global Experiment; differences might be due to an overestimation in the values obtained with the drifters.

Garzoli, S.L. The Atlantic Equatorial Countercurrent: Models and observations. Journal of Geophysical Research, 97(C11):17,931-17,946 (1992).

An analysis of the dynamic height and volume transport variability of the North Equatorial Countercurrent (NECC) in the western tropical Atlantic (west of 38°W) is presented. The study is based upon a subset of the data (16 month-long series of dynamic height obtained with an array of inverted echo sounders) collected in the tropical Atlantic during 1987 and 1988 as part of the National Science Foundation/Tropical Ocean-Global Atmosphere array. Results are compared with those from a previous work in the center of the basin (28°W); a wind product for 1987-1988 is jointly analyzed for further interpretation of the results. In order to obtain transports from the echo sounder data, which do not provide information on the vertical structure of the geostrophic velocities, the product from the Community Model Experiment (CME) is analyzed. In this way the present work follows the objectives: to provide a description of the dynamics of the NECC in a region where maximum reversal is predicted, compare the results with those in the center of the basin,and to validate the product of the CME model.

Garzoli, S.L., Z. Garraffo, G. Podesta, and O.B. Brown. Analysis of a general circulation model product. Part 1: Frontal systems in the Brazil/Malvinas and Kuroshio/Oyashio regions. Journal of Geophysical Research, 97(C12):20,117-20,138 (1992).

In the present paper, the product of the Semtner and Chervin general circulation model (GCM) is compared with available observations in the frontal areas of the Brazil/Malvinas and the Kuroshio/Oyashio confluences. The dimensionality of the systems studied is reduced by using the empirical orthogonal functions (EOF) and frontal density methods. The two sets of data utilized to validate the model are the sea surface temperature (SST) from the satellite observations and temperature fields product from the GCM at levels 1 (12.5 m), 2 (37.5 m) and 6 (160 m). Comparisons are made between the dominant empirical modes and the locus of maximum probability for observations and model product. The model reproduces intense thermal fronts at the surface and in the upper layers. In the upper layer (level 1) they are induced by the internal dynamics of the model and not by the restoring of the model to climatology alone. The variability of these fronts is less pronounced in the model than in the observations. The dominant period in the observations is annual with contributions of semiannual and high frequency oscillations. In the model, the dominant variability is also annual at all analyzed levels. A semiannual oscillation contributed to a lower degree and is related to eddies that, in the model, have an annual and semiannual periodicity.

Gray, W.M., and C.W. Landsea. African rainfall as a precursor of hurricane-related destruction on the U.S. east coast. Bulletin of the American Meteorological Society, 73:1352-1364 (1992).

This paper describes a predictive relationship between west African rainfall and U.S. hurricane-spawned destruction, which is based on information for the 42-year period 1949-1990. It is shown that above-average rainfall during the previous year along the Gulf of Guinea, in combination with above-average rainfall in the western Sahel during June and July, is linked to hurricane-spawned destruction along the U.S. east coast occurring after 1 August, which is 10-20 times greater than in years when pre-August precipitation for these west African regions is below average. Similar hurricane-spawned damage along the U.S. Gulf coast shows only a negligible relationship with African rainfall. Hurricane-caused deaths for both U.S. coastal regions also show a similar association with west African rainfall.

Gray, W.M., C.W. Landsea, P.W. Mielke, and K.J. Berry. Predicting Atlantic seasonal hurricane activity 6-11 months in advance. Weather and Forecasting, 7:440-455 (1992).

A surprisingly strong long-range predictive signal exists for Atlantic-basin seasonal tropical cyclone activity. This predictive skill is related to two measures of west African rainfall in the prior year and to the phase of the stratospheric quasi-biennial oscillation of zonal winds at 30 mb and 50 mb, extrapolated ten months into the future. These predictors, both of which are available by 1 December, can be utilized to make skillful forecasts of Atlantic tropical cyclone activity in the following June-November season. Using jackknife methods to provide independent testing of datasets, it is found that these parameters can be used to forecast nearly half of the season-to-season variability for seven indices of Atlantic seasonal tropical cyclone activity as early as late November of the previous year.

Griffin, J.S., R.W. Burpee, F.D. Marks, and J.L. Franklin. Real-time airborne analysis of aircraft data supporting operational hurricane forecasting. Weather and Forecasting, 7(3):480-490 (1992).

The Hurricane Research Division (HRD) has developed a technique for real-time airborne analysis of aircraft data from reconnaissance and research flights in tropical cyclones. The technique uses an onboard workstation that analyzes flight-level observations, radar reflectivity patterns, radial Doppler velocities, and vertical soundings from Omega dropwindsondes (ODWs). Many of the workstation analyses are in storm-relative coordinates that depend upon interactive identification of the cyclone center from the radar reflectivity data. Displays of the lower fuselage reflectivity, composited for 1-2 h, provide an overall perspective of the horizontal patterns of precipitation and a framework for interpretation of thermodynamic and kinematic observations. The workstation runs algorithms for estimation of the horizontal wind field in the hurricane core using radial velocities measured by the airborne Doppler radar during one or more penetrations of the storm center. Interactive software also supports real-time processing of ODW wind and thermodynamic data, objective editing of bad data, and automatic dissemination of mandatory and significant-level data in the standard dropwindsonde code. Plans for the 1992 hurricane season include transmission of subsets of the data to the National Hurricane Center (NHC) through the Geostationary Operational Environmental Satellite (GOES) communications system and display of the aircraft analyses for the forecasters at NHC. With the implementation of these plans, NHC will receive two-dimensional analyses of the mesoscale precipitation and wind structure of the storm core and more frequent estimates of the location and recent motion of tropical cyclones.

Griffin, J.S., R.W. Burpee, F.D. Marks, and J.L. Franklin. Real-time airborne analysis of flight-level and radar data supporting operational hurricane forecasting. Preprints, 8th International Conference on Interactive Information and Processing Systems for Meteorology, Oceanography, and Hydrology, Atlanta, GA, January 5-10, 1992. American Meteorological Society, Boston, 241-246 (1992).

No abstract.

Hallett, J., W. Hendricks, and P.T. Willis. Evolution of precipitation spectra in a developing convective cloud. Preprints, 11th International Conference on Clouds and Precipitation, Montreal, Canada, August 17-21, 1992. American Meteorological Society, Boston, 216-219 (1992).

No abstract.

Hansen, D.V. Comments on "The significance of half-inertial flow in the eastern equatorial Pacific." Journal of Physical Oceanography, 22(7):811-813 (1992).

It is shown that the instability waves regularly observed in the tropical Pacific and Atlantic Oceans do not necessarily contain oscillations of half the local inertial frequency. Rather, it is hypothesized that the flow approaches the half-inertial conditions only at times when the instability waves develop sufficient baroclinic intensity to saturate the geostrophic vorticity limit of the gradient wind equation for anticyclonic flow.

Hitchcock, G., and T. Whitledge. Nutrient/pigment variability in the Mississippi River plume and adjacent waters. Proceedings, NECOP Workshop on Nutrient Enhanced Coastal Ocean Productivity, Chauvin, Louisiana, October 2-3, 1991. Texas A&M University Press, College Station, 43-51 (1992).

The spatial distribution of salinity, temperature, pigments, and nutrients was examined in the vicinity of the Mississippi River delta and contiguous coastal waters in summer 1990 and spring 1991. The objectives were to document spatial distributions by mapping parameters, and contrast these distributions with temporal patterns near the mouth of Southwest Pass and to the west, near hypoxic bottom waters. The temporal patterns are also compared to observations taken while following a drifting surface instrument package (with a sediment trap array). The mesoscale surface distributions in summer 1990 and spring 1991 show that localized regions of high nitrate exist west of Southwest Pass. Additionally, a maximum in surface chlorophyll was consistently southwest, or downplume, of the highest surface nitrate concentrations. The surface salinity pattern, however, was not consistent from summer to spring. In the summer observations, there was no coherent pattern of low-salinity waters emanating from Southwest Pass; the position of the low-salinity plume was too variable in time to derive a persistent spatial pattern. This was supported by large variations (.10 psu in six hours) in surface salinity while at a fixed position (28°55'N, 89°29'W) near the mouth of Southwest Pass. Temporal variations in surface properties within the plume, while following an instrumented surface drifter, show less variability in surface properties in the Louisiana Bight. The observed time scales of the plume and drifter motions suggest factors such as tides and inertial motions are forcing mediating the variability in surface properties near Southwest Pass.

Houze, R.A., F.D. Marks, and R.A. Black. Dual-aircraft investigation of the inner core of Hurricane Norbert. Part II: Mesoscale distribution of ice particles. Journal of the Atmospheric Sciences, 49(11):943-962 (1992).

Horizontal fields of cloud microphysical parameters, vertical air motion, and horizontal wind at the 6 km level in Hurricane Norbert (1984) were obtained by mapping and interpolating data collected on board a WP-3D aircraft along numerous flight tracks executed within the central region of the storm. Although the storm was characterized by a strong vortex of winds reaching peak values >50 m s^-1 all around the storm, the precipitation was concentrated on the southwest side of the storm. A sloping eyewall was located within 20-30 km of the eye. Stratiform precipitation dominated the region outside the eyewall. A band of maximum stratiform precipitation was located 60-70 km southwest of the storm center. The ice particles at flight level tended to be relatively large both in the eyewall and in the outer band of stratiform precipitation. Particles were smaller and more numerous (100-300 l^-1) in the zone between the eyewall and outer stratiform band. These particles occurred on the outside edges of the eyewall convective updrafts, indicating that they may have been produced by splintering in association with graupel formation in the updrafts. The large particles in the eyewall tended to be graupel. In the outer stratiform region, characterized by weak, average vertical air motion and an absence of strong convective drafts, the predominant particle type was aggregates. The region of large graupel particles in the eyewall coincided with the radius of maximum tangential wind and was apparently produced by the azimuthal advection of the graupel particles. Since graupel particles fall rapidly, they were not susceptible to advection out of the weaker radial wind component. On the other hand, some of the more slowly falling, less dense aggregates produced in the eyewall region were evidently advected radially as well as azimuthally, thus accounting for the location of the outer region of maximum stratiform precipitation intensity.

Knox, M., P.D. Quay, and D. Wilbur. Kinetic isotopic fractionation during air-water gas transfer of O₂, CH₄, and H₂. Journal of Geophysical Research, 97(C12):20,335-20,343 (1992).

We present experimental results that show that the kinetic isotopic fractionation during gas exchange is 0.9972 � 0.0002 for oxygen, 0.9992 � 0.0002 for methane, 0.9987 � 0.0001 for nitrogen, and 0.982 � 0.002 for hydrogen, and that the equilibrium fractionation between water and gas phases is 1.037 for hydrogen. We show that the isotopic fractionation during gas transfer for these gases is not equal to the square root of their reduced mass in water, as would be predicted by an extension of the kinetic theory of ideal gases to dissolved gases. The use of isotopes as tracers of biogeochemical gases requires knowledge of the fractionation factor for air-water gas transfer; there have been few direct measurements of these factors.

Landsea, C.W., and W.M. Gray. The strong association between western Sahelian monsoon rainfall and intense Atlantic hurricanes. Journal of Climate, 5(5):435-453 (1992).

Seasonal variability of Atlantic basin tropical cyclones is examined with respect to the monsoon rainfall over west Africa. Variations of intense hurricanes are of the most interest, as they are responsible for over three-quarters of United States tropical cyclone spawned destruction, though they account for only one-fifth of all landfalling cyclones. Intense hurricanes have also shown a strong downward trend during the last few decades. It is these storms that show the largest concurrent association with Africa's western Sahelian June-September rainfall for the years 1949-1990. Though the Sahel is currently experiencing a multidecadal drought, the relationship between Atlantic tropical cyclones and western Sahelian rainfall is not dependent on the similar downward trends in both datasets. A detrended analysis confirms that a strong association still exists, though reduced somewhat in variance explained. Additionally, independent data from the years 1899 to 1948 substantiate the existence of the tropical cyclone-western Sahelian rainfall association. The fact that the Sahel periodically experiences multidecadal wet and dry regimes suggests that the current Sahelian drought, which began in the late 1960s, could be a temporary condition that may end in the near future. When this occurs, the Atlantic hurricane basin--especially the Caribbean islands and the United States east coast--will likely see a large increase in intense hurricane activity associated with abundant Sahelian rainfall similar to the period of the late 1940s through the 1960s.

Landsea, C.W., W.M. Gray, P.W. Mielke, and K.J. Berry. Long-term variations of western Sahelian monsoon rainfall and intense U.S. landfalling hurricanes. Journal of Climate, 5(5):1528-1534 (1992).

Western Salelian rainfall during the primary rainy season of June through September is shown to be significantly associated with concurrent intense U.S. landfalling hurricanes during the last 92 years. The most intense hurricanes (i.e., Saffir-Simpson scale category 3, 4, or 5) have an especially strong relationship with Sahelian rainfall, whereas weaker hurricanes show little or no association. The hurricane-Sahelian rainfall association is most evident along the U.S. east coast but is negligible in the U.S. Gulf coast region.

Landsea, C.W., W.M. Gray, P.W. Mielke, and K.J. Berry. Seasonal forecasting of Atlantic basin tropical cyclones by 1 June. Proceedings, 17th Annual Climate Diagnostics Workshop, Norman, OK. NOAA, 388-390 (1992).

No abstract.

Marks, F.D. Kinematic structure of the hurricane inner core as revealed by airborne Doppler radar. Preprints, 5th Conference on Mesoscale Processes, Atlanta, GA, January 5-10, 1992. American Meteorological Society, Boston, 127-132 (1992).

No abstract.

Marks, F.D., R.A. Houze, and J.F. Gamache. Dual-aircraft investigation of the inner core of Hurricane Norbert. Part I: Kinematic structure. Journal of the Atmospheric Sciences, 49(11):919-942 (1992).

A dedicated experiment to study the details ofthe important physical processes and scale interactions operative within the eyewall regions of Hurricane Norbert was carried out on 24-25 September. The two National Oceanic and Atmospheric Administration (NOAA) Aircraft Operations Center (AOC) WP-3D research aircraft were used for the study. One aircraft, equipped with airborne Doppler radar, flew repeated radial penetrations in and out of the eye, mapping the three-dimensional wind field over the region surrounding the eyewall. This data set provides the first complete mapping of the three-dimensional wind field of the hurricane inner core. The three-dimensional wind field within 40 km of the storm center was derived from a "pseudo" dual-Doppler analysis in each quadrant of the storm. The vertical wind components were derived from the mass continuity equation and the horizontal wind field. The Doppler-derived wind fields for the four quadrants were combined to form a storm composite wind field that was 75 × 75 km on a side and centered on the storm circulation center. The wind-field altitude extended from 0.5-12 km. The Norbert wind field was asymmetric, and the asymmetry varied with altitude. The tangential wind maximum sloped upwind with increasing altitude, from the left of the track (azimuths 147°-327°) at 1 km altitude to the right of the storm track (azimuths 327°-147°) at 3 km altitude. The radial wind at 1 km altitude had inflow in front of the storm (327° azimuth) and outflow behind. This pattern in the radial flow disappeared at 3 km altitude, where the radial flow switched from inflow in the rear of the storm to outflow in the front. The vertical velocity maximum was to the left of the storm track at all levels. The maximum sloped downwind with increasing altitude (along the upper boundary of the reflectivity maximum) from in front of, and to the left of, the track at 2 km altitude, to behind and to the right of the track at 8 km altitude. To investigate the nature of the wind-field asymmetry, a technique was devised to partition the horizontal wind components into a horizontal mean wind as a function of the altitude and a perturbation wind. The cylindrical nature of the wind field permitted further partitioning of the perturbation wind into the mean vortex (a function of radius and height-wave number 0) and a perturbation from the mean vortex (including any higher order wave numbers). The wind partitioning was used to describe the structure of the mean vortex and its interaction with the environmental flow. The partition of the horizontal wind pointed out the complex interactions of the wind components in determining storm motion and in forcing mesoscale convergence/divergence patterns that resulted in the vertical velocity asymmetry.

Maul, G.A. Global temperature and sea level change. Physics and Society, 21(5):6-8 (1992).

No abstract.

Maul, G.A. Temperature and sea level change. In Global Warming: Physics and Facts, B.G. Levi, D. Hafemeister, and R.A. Scribner (eds.). American Institute of Physics, New York, 78-112 (1992).

Instrumental measurements of air and sea temperature and of sea level are rarely more than a century in length, and are characterized by numerous observational inconsistencies. True "global" data sets do not exist, except from satellite measurements during the last decade, primarily because most of the 71% of Earth's surface covered by the oceans is not sampled. Surface air-land temperature records are plagued by changes in measurement techniques, location of thermometers, and microclimate changes, notably urbanization. Surface marine air temperatures, too, are affected by changing ship design, height of thermometers, and particularly, daytime biases. Sea surface temperature data have similar difficulties, plus the added problems of changed ship routes, and shifting from bucket to engine intake observations. Sea levels from coastal tide gauges have notably shorter record-lengths than temperature records, and often are dominated by diastrophism and subsidence at the lowest frequencies. Determining statistically significant climatic trends in any of these geophysical time series leads to uncertain results due to natural variability such as El Ni�o-Southern Oscillation events.

Maul, G.A., D.V. Hansen, and N.J. Bravo. A note on sea level variability at Clipperton Island from GEOSAT and in-situ observations. In Sea Level Changes: Determination and Effects, P.L. Woodworth, D.T. Pugh, J.G. DeRonde, R.G. Warrick, and J. Hannah (eds.). Geophysical Monograph Series, Volume 69, 145-154 (1992).

During the 1986-1989 Exact Repeat Mission (ERM) of GEOSAT, in-situ observations of sea level at Clipperton Island (10°N/109°W) and satellite-tracked, free-drifting drogued buoys in the eastern tropical Pacific Ocean are concurrently available. A map of the standard deviations of GEOSAT sea surface heights (2.9 years) shows a variance maximum along ~12°N from Central America, past Clipperton to ~160°W. Seafloor pressure gauge observations from a shallow (10 m depth) site on Clipperton Island and an ERM crossover point in deep water nearby show a correlation of r = 0.76 with a residual of ±6.7 cm RMS. Approximately 17% of the difference (GEOSAT minus sea level) is characterized by a 4 cm amplitude 0° phase annual harmonic, which is probably caused by unaccounted-for tropospheric water vapor affecting the altimeter and/or ERM orbit error removal. Wintertime anticyclonic mesoscale eddies advecting past Clipperton Island each year have GEOSAT sea surface height and in-situ sea level signals of more than 30 cm, some of which are documented by the satellite-tracked drifters. Meridional profiles of the annual harmonic of zonal geostrophic current from GEOSAT and from the drifters both show synchronous maxima in the North Equatorial Countercurrent and the North Equatorial Current. Other Clipperton sea level maxima seen during late spring of each year may involve anticyclonic vortices formed along Central America the previous winter.

Mestas-Nunez, A.M., D.B. Chelton, and R.A. deSzoeke. Evidence of time-dependent Sverdrup circulation in the South Pacific from the SEASAT scatterometer and altimeter. Journal of Physical Oceanography, 22(8):934-943 (1992).

SEASAT scatterometer and altimeter data are analyzed to investigate time-dependent Sverdrup dynamics in the Southern Ocean (40°S to 60°S) over seasonal time scales. Sverdrup dynamics are shown to be inadequate to describe the circulation in the South Atlantic and Indian oceans. The Sverdrup circulation in the South Pacific is reasonable north of 55°S. The changes in Sverdrup circulation from July to September 1978 indicate an eastward acceleration along 55°S and westward acceleration along 40°S, suggesting a southward shift in the subpolar eastward flow. Sea level in the South Pacific is estimated for July and September 1978 from scatterometer vector wind data based on Sverdrup dynamics assuming a flat-bottom ocean with barotropic flow. The changes in Sverdrup sea level are compared with the changes in sea level observed by the altimeter for the same time period. Both estimates indicate a rise in sea level along a zonal band centered at about 50°S. This sea level rise inferred from both the scatterometer and altimeter data is supported by a similar rise in sea level observed from tide gauge measurements at two locations in New Zealand. The spatial correlation between the two satellite estimates of sea level change is about 0.5. This agreement suggests that time-dependent Sverdrup dynamics may account for about 1/4 of the spatial variance of sea level change in the South Pacific over the three-month SEASAT mission.

Mielke, P.W., K.J. Berry, W.M. Gray, and C.W. Landsea. Cross-validated prediction models for 1 December and 1 August forecasts of seasonal tropical cyclone activity in the Atlantic basin. Preprints, 12th Conference on Probability and Statistics in Atmospheric Sciences, Toronto, Canada. American Meteorological Society, Boston (1992).

No abstract.

Millero, F.J., and J.-Z. Zhang. Total alkalinity measurements in the South Atlantic. Data Report, University of Miami, 63 pp. (1992).

This report gives the results of our pH, total alkalinity (TA), and total inorganic carbon dioxide (TCO₂) measurements made in the South Atlantic from June 11 to August 6, 1991 on the NOAA R/V Malcolm Baldridge. The results were obtained by a potentiometric titration of seawater samples with HCl. The resulting pH, TA, and TCO₂ are thought to be precise to ± 0.01 in pH, ± 3 µmol/kg in TA, and ± 5 µmol/kg in TCO₂. These results will be combined with the NOAA's measurements made by Rik Wanninkhof to characterize the CO₂ system in this region.

Molinari, R.L., R.A. Fine, and E. Johns. The Deep Western Boundary Current in the tropical North Atlantic Ocean. Deep-Sea Research, Part I, 39(11-12):1967-1984 (1992).

Tracer and CTD data collected on four cruises to the western tropical North Atlantic Ocean during 1987-1989 are used to describe the Deep Western Boundary Current (DWBC). The study area extends along the boundary and east to the Mid-Atlantic Ridge from 14.5°N to just north of the equator. Two cores of recently ventilated (with respect to the chlorofluorocarbon F11) northern hemisphere water are advected through the area. A shallow core is centered at about 1,500 m and a deeper core at about 3,500 m. The upper core of high F11 (bounded by the 3.2°C and 4.7°C potential temperature isotherms) is typically located inshore of the deeper currents,and transports were computed relative to a zero reference velocity on the 4.7°C potential temperature surface. Total transport below the 4.7°C surface for the most intense portion of the DWBC is 26 Sv (1 Sv = 10⁶ m³/s). Of this total, 17 Sv is contained in the two recently ventilated high F11 cores. The Ceara Rise blocks equatorward flow in the DWBC below the 1.8°C potential temperature surface, causing the coldest waters to recirculate back to the north.

Murray, J.W., M.W. Leinen, R.A. Feely, J.R. Toggweiler, and R.H. Wanninkhof. EqPac: A process study in the central equatorial Pacific. Oceanography, 5(3):134-142 (1992).

EqPac is the United States-Joint Global Ocean Flux Study (US-JGOFS) process study in the central equatorial Pacific. The first EqPac cruises sailed in January 1992 during a moderately strong El Ni�o. This was fortuitous for our studies of chemical and biological distributions because El Ni�o events are difficult to predict, and the lead time for a project of this size is long. There was virtually no previous upper-water-column chemical or biological data for El Ni�o conditions in the central equatorial Pacific. Now an El Ni�o has been studied in considerable detail, and it will be easy to sample the extremes in environmental conditions by sampling non-El Ni�o conditions (including La Ni�a) in 1993 and the years thereafter. The implementation of EqPac illustrates how difficult it is to mount a large-scale interdisciplinary study of the ocean when the interannual variability is large.

Peene, S.J., Y.P. Sheng, and S.H. Houston. Modeling tidal and wind-driven circulation in Sarasota and Tampa Bays. Proceedings, International Conference on Estuarine and Coastal Modeling, St. Petersburg, FL, November 13-15, 1991. American Society of Civil Engineers, New York, 357-369 (1992).

As part of an effort to quantify the effects of hydrodynamics on water quality within Sarasota Bay, Tampa Bay, and their adjoining waters, a field and modeling study of circulation and transport is being conducted. This paper presents some results from a simulation of barotropic circulation in Tampa and Sarasota Bays during October 1990. Tropical Storm Marco passed just west of the study area on October 11. At that time, NOAA was conducting measurements of tides and currents at a number of stations in Tampa Bay, and USGS had stations monitoring tides in Sarasota Bay. To simulate the circulation, the recently enhanced CH3D model (Sheng, 1989), which was originally developed for Chesapeake Bay, James River, and Lake Okeechobee, was used. To allow sufficient lateral resolution in the vicinity of shorelines and inlets, a boundary-fitted grid with a rather fine grid spacing (between 200 and 1000 m) was generated for the region from Tampa Bay in the north, south to Venice Inlet, and approximately 4 km into the Gulf of Mexico. For the Tropical Storm Marco simulation, a wind field was generated by NOAA's Hurricane Research Center using a two-dimensional least squares fitting algorithm on surface and aircraft winds measured as the storm moved northward along the Florida coast. Based on an objective comparison between simulated and measured results, it is apparent that the model predicts the tidal and wind-driven water surface elevation well, while the prediction of currents is not as good due to the lack of resolution of the navigation channel in the numerical grid.

Peng, T.-H. Possible effects of ozone depletion on global carbon cycle. Radiocarbon, 34(3):772-779 (1992).

The increase of UV-B radiation resulting from ozone depletion is considered to have damaging effects on marine ecosystems. A cutback of marine productivity would tend to reduce the oceanic uptake of atmospheric CO₂. Box models of the global oceans based on the distribution of bomb-produced ¹⁴C are used to evaluate the possible effects of ozone depletion on the atmospheric CO₂ concentration. The maximum effect presumably takes place if the ozone hole reduces the marine productivity to zero in the Antarctic Ocean. In a business-as-usual scenario of future CO₂ emissions, the atmospheric CO₂ partial pressure (pCO₂) would increase by an additional 37 µatm over the course of the next century. This increase corresponds to 4.6% of the projected atmospheric pCO₂ in the year 2090. However, if the damaging effect caused by the destruction of the stratospheric ozone layer is assumed to lower the productivity over the Antarctic Ocean by 10%, the atmospheric pCO₂ would rise by less than 3 µatm over the expected atmospheric level in the next century.

Peng, T.-H., and W.S. Broecker. Reconstruction of radiocarbon distribution in the glacial ocean. In Radiocarbon After Four Decades: An Interdisciplinary Perspective, R.E. Taylor, A. Long, and R.S. Kra (eds.). Springer-Verlag, New York, 75-92 (1992).

No abstract.

Peng, T.-H., W.S. Broecker, and H.G. Ostlund. Dynamic Constraints on CO₂ Uptake by an Iron-Fertilized Antarctic, Modeling The Earth System, D. Ojima (ed.). Global Change Institute, Volume 3, 77-106 (1992).

No abstract.

Post, W.M., F. Chavez, P.J. Mulholland, J. Pastor, T.-H. Peng, K. Prentice, and T. Web. Climate feedbacks in the global carbon cycle. In The Science of Global Change: The Impacts of Human Activities on the Environment, D.A. Dunnette and R.J. O'Brien (eds.). American Chemical Society, 392-412 (1992).

Increasing atmospheric CO₂ is likely to produce chronic changes in global climate, as it may have done in the geologic past. Future CO₂-induced changes in temperature and precipitation distribution changes could equal or exceed the changes which have occurred over the past 160,000 years and have affected the global carbon cycle. We consider ocean and terrestrial processes that could involve large change in carbon fluxes (>2 Pg C·yr^-1) or changes in storage in large carbon pools (>200 Pg C) resulting from CO₂-induced climate changes. These include (1) air-sea exchange of CO₂ in response to changes in temperature and salinity; (2) climate-induced changes in ocean circulation; (3) changes in oceanic new production and regeneration of organic debris caused directly by climate change; (4) altered oceanic nutrient supply needed to support new production due to climate-induced alteration of ocean circulation and river discharge; (5) CaCO₃ compensation in sea water; (6) altered river nutrient flux and effects on coastal organic matter production and sediment accumulation; (7) seasonal balance between GPP and decomposition-respiration in terrestrial ecosystems in response to changes in temperature and precipitation; (8) successional processes in terrestrial ecosystems and formation of new plant associations in response to climatic change; (9) effects on soil nutrient availability, which amplifies ecosystem responses to climate change; (10) and responses of northern forests, tundra, and peatlands which have, until recently, been a sink for CO₂. The potential effect of these processes on the rate of atmospheric CO₂ concentration changes are estimated where possible, but not much quantitative information at a global scale is known, so uncertainty in these estimates is high. Each of these secondary feedbacks, however, has the potential of changing atmospheric CO₂ concentration in magnitude similar to the effects of the direct human processes (fossil fuel burning and land clearing) responsible for the concern about global warming in the first place. It is, therefore, urgent that these uncertainties be resolved. Lines of research to accomplish this are suggested.

Powell, M.D. Surface wind speeds in hurricanes. Proceedings, ASCE Structures, Congress X, San Antonio, TX, April 13-15, 1992. American Society of Civil Engineers, New York, 246-249 (1992).

No abstract.

Pszenny, A.A.P. Particle size distributions of methanesulfonate in the tropical Pacific marine boundary layer. Journal of Atmospheric Chemistry, 14(1-4):273-284 (1992).

Fourteen high-volume cascade impactor samples were collected during a January-February 1990 research cruise in the tropical Pacific from Panama to 180°. Aqueous extracts of the samples were analyzed for methanesulfonate (MSA), sulfate, and the seasalt tracer ion magnesium. The majority of MSA-size distributions showed no pronounced maximum on submicrometer particles, as has been observed elsewhere. Analysis of the data indicated that MSA was distributed essentially uniformly with the effective surface area of particles <0.5 µm in radius, which were primarily seasalt. Relatively less MSA was found in smaller particles, which were primarily sulfate. These results are consistent with those from theoretical and laboratory experimental studies reported in the literature which suggest that MSA produced from photochemical oxidation of dimethylsulfide condenses on pre-existing particles in strong preference to nucleating into new particles. This implies that MSA may not contribute appreciably to enhancing cloud condensation nucleus populations in the remote tropical marine atmosphere.

Richardson, P.L., S. Arnault, S.L. Garzoli, and J.G. Bruce. Annual cycle of the Atlantic North Equatorial Countercurrent. Deep-Sea Research, 39(6):997-1014 (1992).

An analysis of numerous meridional XBT sections near 28°W reveals that the geostrophic North Equatorial Countercurrent (NECC) continues to flow eastward throughout the year, fastest in fall and slowest in spring. Drifting buoys and historical ship drifts show that the near-surface Countercurrent reverses each spring even when systematic errors due to windage are taken into account. The seasonally fluctuating winds drive an Ekman surface current that is eastward in fall, adding to the geostrophic current, and westward in spring, countering and overwhelming the geostrophic current. The reversal of the Countercurrent in spring occurs in the near-surface layer and is driven by the Northeast Trades. Thus, the near-surface velocity in the Countercurrent is determined by a competition between local wind stress and the larger field of wind stress curl, both of which have large seasonal variations in the tropical Atlantic.

Robinette, M., S.R. Piotrowicz, A.S. Artz, and T. Pizer. Meteorological conditions over the South Atlantic Ocean during July and August of 1991. NOAA Technical Memorandum, ERL AOML-70 (PB92-235738), 136 pp. (1992).

In the austral winter of 1991, the NOAA ship Malcolm Baldrige conducted a research cruise in the South Atlantic Ocean investigating ozone, carbon dioxide, and other related trace species which may be significant to the earth's radiation balance. To better understand the environmental conditions accompanying the acquired air samples, meteorological data were collected on board ship using twice daily rawinsondes. The meteorological data are presented using soundings and cross-sections along with synoptic maps and back-trajectories developed during post-cruise analyses. The synoptic maps illustrate the general meteorological conditions of the area in terms of pressure distributions at mean sea-level while the back-trajectories illustrate the flow of an air parcel due to the synoptic conditions over the ten days prior to reaching the ship. Sounding data obtained from rawinsonde launches on board ship present the vertical structure of the atmosphere using four variables: temperature, relative humidity, potential temperature, and wind. The cross-sections give an overall view of the change in a parameter over a horizontal distance between two points illustrating general outlines of the meteorological regimes encountered.

Rona, P.A., and D.A. Trivett. Discrete and diffuse heat transfer at ASHES vent field, Axial Volcano, Juan de Fuca Ridge. Earth and Planetary Science Letters, 109(1-2):57-71 (1992).

Heat fluxes of discrete and diffuse components of hydrothermal discharge are estimated from submersible measurements in the ASHES vent field located in the caldera of Axial Volcano at the central Juan de Fuca Ridge. The discrete component comprises discharge from individual vents and the diffuse component comprises seepage from large areas of the seafloor. The investigation centered on the high-temperature portion of the field, a 100 x 100 m area of fractured lobate and sheet lava flows encompassing discrete discharge (<326°C) from seven individual vents and diffuse flow from intervening areas. A total of 4.4 � 2 x 10⁶W was estimated for the discrete heat flux based on measurements of effluent temperature, flow rate, and orifice diameter at all the known individual vents by DSV ALVIN in September 1987. A total of 15-75 x 10⁶W was calculated with a standard plume model for the diffuse flux based on a grid of temperature measurements at altitudes of 1 m and 20 m above the study area using a 1 m long vertical array of temperature sensors mounted at the front of DSV ALVIN's instrument platform. The study indicates that: (1) the diffuse component rises separately from the discrete component of hydrothermal discharge and is laterally advected by a prevailing current below the discrete component; and (2) the diffuse component of convective heat flux is approximately an order of magnitude greater than the discrete component in the high-temperature portion of the ASHES vent field.

Rona, P.A., P.J. Meis, C.A. Beaverson, R.W. Embley, and C.G. Fox. Geologic setting of hydrothermal activity at the northern Gorda Ridge. Marine Geology, 106(3-4):189-201 (1992).

The northern end of the rift valley of the Gorda Ridge was investigated with Sea Beam bathymetry, SeaMARC IA and II side-scan sonar, surface-towed magnetics, and near-bottom, camera-temperature tows to determine the geologic setting of large chemical anomalies in the water column indicative of intense hydrothermal discharge comparable to anomalies associated with the Sea Cliff hydrothermal field situated on the east wall of the rift valley 25 km to the south. Water column and seafloor hydrothermal indicators and tectonic trends converge on a seamount at 42°57.3'N, 126°33.0'W on a terrace 4.5 km east of the rift valley axis as the most likely source area for the hydrothermal discharge. Comparison with the geologic setting of the Sea Cliff hydrothermal field confirms the presence of an anomalous axis-oblique tectonic trend that permeates the structure of the northern Gorda Ridge. Additional sinistral offset along an axis-perpendicular structural trend at the Sea Cliff field indicates a southward increase in deformation of the northern Gorda Ridge along axis-transverse trends.

Rona, P.A., H. Bougault, J.L. Charlou, P. Appriou, T.A. Nelsen, J.H. Trefry, G.L. Eberhart, A. Barone, and H.D. Needham. Hydrothermal circulation, serpentinization and degassing at a rift valley-fracture zone intersection: Mid-Atlantic Ridge near 15°N, 45°W. Geology, 20(9):783-786 (1992).

A hydrothermal system characterized by high ratios of methane to both manganese and suspended particulate matter was detected in seawater sampled at the eastern intersection of the rift valley of the Mid-Atlantic Ridge with the Fifteen-Twenty Fracture Zone. This finding contrasts with low ratios in black smoker-type hydrothermal systems that occur within spreading segments. Near-bottom water sampling coordinated with SeaBeam bathymetry and camera-temperature tows detected the highest concentrations of methane at fault zones in rocks with the appearance of altered ultramafic units in a large dome that forms part of the inside corner high at the intersection. The distinct chemical signatures of the two types of hydrothermal systems are inferred to be controlled by different circulation pathways related to reaction of seawater primarily with ultramafic rocks at intersections of spreading segments with fracture zones but with mafic rocks within spreading segments.

Routt, J.A., and W.D. Wilson. Shipboard acoustic Doppler current profiler data collected during the Western Tropical Atlantic Experiment (WESTRAX), 1991. NOAA Technical Memorandum, ERL AOML-72 (PB93-141612), 152 pp. (1992).

Shapiro, L.J. Hurricane vortex motion and evolution in a three-layer model. Journal of the Atmospheric Sciences, 9(2):140-153 (1992).

A three-layer, multinested numerical model is used to evaluate the asymmetric evolution of a hurricane and its interaction with the large-scale environment. The model uses a compressible fluid in isentropic coordinates. In 72 h the hurricane vortex on a beta plane moves northwest at an average speed of 2.4 m s^-1. In the presence of a westerly zonal wind in the upper model layer, the hurricane on an f plane moves to the southeast at an average speed of 0.9 m s^-1. A series of experiments establishes that the southeastward drift in the presence of westerly shear is primarily due to the southward isentropic gradient of background potential vorticity (PV) in the middle model layer that is associated with the background temperature field. The cyclonic circulation advects low PV air southward on the west side of the vortex, inducing a negative isentropic PV anomaly to the southwest. This anomaly is associated with a wind field that advects the vortex to the southeast, just as the northward isentropic gradient of PV due to the beta effect advects the hurricane to the northwest. The northward gradient of background PV in the upper layer has little effect on the motion. The westerly wind advects upper layer low PV outside the vortex core to the east, inducing an anticyclonic anomaly that tends to advect the middle-layer vortex to the north; this tendency is secondary to the motion. The role of vertical transports of momentum due to cumulus convection on the hurricane motion is also evaluated. Results are presented that generalize the homogenization of asymmetric absolute vortex and oscillation in relative angular momentum (RAM) found on the beta plane in a previous study with a barotropic model. Outside the vortex core and within ~350 km of the center, the asymmetries reach a near-steady state. The middle-layer asymmetry is associated with a PV gradient that neutralizes the background gradient due to planetary vortex or environmental temperature, thereby insulating the symmetric vortex from distortion. Horizontal fluxes in the presence of the planetary vortex gradient tend to counteract the development of strong anticyclonic total RAM within a large circle about the vortex center.

Snyder, R.L., L.M. Lawson, and R.B. Long. Inverse modeling of the action-balance equation. Part I: Source expansion and adjoint-model equations. Journal of Physical Oceanography, 22(12):1540-1555 (1992).

In this paper a series of numerical experiments is defined to explore the inverse modeling of the action-balance equation governing the evolution of the surface gravity wave field, using the adjoint data-assimilation model-optimization procedure of Thacker and Long. We begin by exploiting power series, functional power series, and a variety of physical and mathematical considerations to derive a systematic expansion of the source terms in this equation for the deep-water case. This expansion, which naturally incorporates a Thacker representation for the nonlinear transfer from wave-wave interaction, defines a set of dimensionless expansion coefficients to be determined by the inverse modeling and identifies the simplified cases to be investigated in the numerical experiments. Dimensional analysis determines a natural scaling for each term in this expansion and suggests a general form for the whitecap dissipation term, which includes as a special case the form proposed by Hasselmann, determining the first-order contribution to his unknown spectrum-dependent coefficient to within a multiplicative spectrum-independent constant. A general discussion of the evolution of the simplified cases reveals a striking tendency to concentrate action in a single band when whitecap dissipation has the Hasselmann form and nonlinear transfer is ignored. A derivation of the adjoint-model equations is included for one of the simplified cases and a general discussion of the model-optimization procedure is given. In these equations, nonlinear transfer is mirrored by a term of similar form, with Thacker's nonlinear transfer coefficients replaced by a related set of adjoint coefficients and the triple product of spectral intensities replaced by a product of two spectral intensities and a Lagrange multiplier.

Springer-Young, M., S.R. Piotrowicz, and G.R. Harvey. Impact of an episodic event on copper and zinc concentrations and speciation in surface waters of the Gulf of Mexico. Deep-Sea Research, Part I, 39(6):953-964 (1992).

Electrochemical and chelation/extraction trace metal techniques are used to develop an understanding of changes in copper and zinc concentrations and speciation associated with a hydrographic and atmospheric event which occurred during an eight-day station in the Gulf of Mexico. Changes in copper and zinc concentrations and speciation coincided with physical changes and biological productivity simulation. In normally oligotrophic water masses it is possible that episodic events, such as inputs from beneath the mixed layer or aeolian transport, may impact the interaction of trace metals and marine biological processes.

Thacker, W.C. Oceanographic inverse problems. Physica D, 60(1-4):16-37 (1992).

Oceanographic inverse problems are generalizations of the concept of linear regression to encompass the fitting of numerical models based on the partial-differential equations of fluid dynamics to oceanic data by adjusting surface fluxes, initial conditions, and/or transport parameters. The limited resolution of the data requires some sort of regularizing assumptions similar to those needed for spatial interpolation. Computationally, they are nonlinear-least-squares problems involving very many variables. These problems can be ill-conditioned due to the indirect nature of the observations, to the way the dynamics enter, and to the effect of the regularizing assumptions. Solving such large optimization problems requires efficient computation of derivatives of functions defined by computational codes. The adjoint method provides derivatives with respect to all the code's many adjustable inputs for roughly the same cost as computing a single model simulation. Although computationally difficult, model fitting offers the promise of dynamically consistent multivariate analyses of oceanographic data.

Trefry, J.H., R.P. Trocine, S. Metz, T.A. Nelsen, and N. Hawley. Suspended particulate matter on the Louisiana shelf: Concentrations, composition and transport pathways. Proceedings, NECOP Workshop on Nutrient Enhanced Coastal Ocean Productivity, Chauvin, LA, October 2-3, 1991. Texas A&M University Press, College Station, 126-130 (1992).

The concentrations, composition and transport pathways of suspended particulate matter and particulate organic carbon (POC) have a direct bearing on the development and persistence of shelf hypoxia, as well as on the global cycling of carbon. More than 120 CTD-transmissometer profiles and >400 particle samples were collected from the Mississippi River and adjacent Gulf of Mexico on cruises during July-August 1990 and February 1991. River-flow is a dominant factor in controlling particle distributions; however, time-series data show that tides and weather fronts can greatly influence concentrations and movement of suspended matter. Results from chemical analyses show that concentrations of POC range from >80 µmol/L (>1 mg/L) at near river locations to <0.8 µmol/L (<0.01 mg/L) in some deep offshore waters. The organic fraction of the suspended matter increases from <5% of the total mass near the river mouth to >90% along the shelf at about 10 km from the river. The C/N molar ratio in suspended particles from throughout the shelf is near uniform at 6. Plumes of particle-rich water at outer shelf depths of about 100 m, along with transport in near-bottom nepheloid layers, carry a POC burden that can be traced tens of kilometers offshore.

Tsai, J.J., J.R. Proni, W.P. Dammann, and N.C. Kraus. Dredged material disposal at the edge of the Florida Current. Chemistry and Ecology, 6(1-2):169-187 (1992).

A field data collection project was undertaken to investigate the short-term fate of dredged material discharged in the designated Miami Ocean Dredged Material Disposal Site (ODMDS) before dredging of the Miami River and the Miami Harbor Turning Basin begins. The designated ODMDS is located in relatively deep water for discharge sites with typical bottom depth of 150 m and is also located in the western boundary region of the Gulf Stream current off Miami. Acoustical backscattering, current, particulate, temperature, and salinity data were gathered over a three-day period from April 24, 1990 through April 26, 1990. The major generic features of shallow-water discharge plumes were observed to be present: (a) the presence of a rapid convective descending plume portion; (b) impact of that plume portion with the ocean bottom and concomitant generation of bottom surge; (c) rapid horizontal width growth of the descending plume through entrainment; and (d) retention of a residual plume portion within the water column. A well-mixed upper water column layer extending to a depth of 40 to 60 m below the surface of the ocean permitted measurements of the plume entrainment coefficient free from bottom boundary, water column density gradient, and vertical current shear effects which are usually present in relatively shallow, e.g., less than 40 m bottom depth, coastal ocean discharge studies. Entrainment coefficient estimates obtained in this study were between 0.5 to 0.7. The residual water plume material was tracked over one-half hour during each of eight discharge events and was transported in a north-northeast direction.

Tziperman, E., W.C. Thacker, and K. Bryan. Computing the steady oceanic circulation using an optimization approach. Dynamics of Atmospheres and Oceans, 16(5):379-403 (1992).

The traditional method for computing steady oceanic circulation has been by stepping an oceanic model forward in time until transients are damped by friction. An alternative method, which has the potential for being more economical, is to minimize the sum of the squares of the residuals of the steady model equations. A variety of algorithms might be considered for computing the minimum; attention here is focused on preconditioned conjugate-gradient descent with the gradient computed using an adjoint model. The choice of variables, i.e., the preconditioning transformation used in the optimization process, is found to be critical to the efficiency of the method. An appropriate preconditioning transformation can be suggested by a heuristic analysis similar to that commonly used to test the stability of numerical models. The method is demonstrated within the context of the barotropic vorticity equation, and results indicate that the method can be at least as efficient as time-stepping.

Tziperman, E., W.C. Thacker, R.B. Long, and S.-M. Hwang. Oceanic data analysis using a general circulation model. Part 1: Simulations. Journal of Physical Oceanography, 22(12):1434-1457 (1992).

This paper deals with the solution of inverse problems involving complex numerical models of the oceanic general circulation and large data sets. The goal of these inverse problems is to find values for model inputs consistent with a steady circulation and, at the same time, consistent with the available data. They are formulated as optimization problems, seeking values for the model's inputs that minimize a cost function measuring departure from steady state and from data. The two main objectives of this work are (1) to examine the feasibility of solving inverse problems involving a realistic numerical model of the oceanic general circulation, and (2) to understand how the optimization uses various data to calculate the desired model parameters. The model considered here is similar to the primitive equations model of Bryan (1969) and of Cox (1984), the principal difference being that here the horizontal momentum balance is essentially geostrophic. The model's inputs calculated by the optimization consist of surface fluxes of heat, water, and momentum, as well as the eddy-mixing parameters. In addition, optimal estimates for the hydrography are obtained by requiring the hydrography to be consistent with both other types of data and the model's dynamics. In the examples presented here, the data have been generated by the model from known inputs; in some cases simulated noise has been added. The cost function is a sum of terms quadratic in the differences between the data and their model counterparts and terms quadratic in the temperature and salinity time rate of change as evaluated using the model equations. The different inverse problems considered differ in the choice of the model inputs calculated by the optimization and in the data used in the cost function. Optimal values of the model's inputs are computed using a conjugate-gradient minimization algorithm, with the gradient computed using the so-called adjoint method. In examples without added noise, solutions for the model inputs were found efficiently and accurately. This was not the case when simulated data with randomly generated noise were used. Amplification of noise was especially felt in regions of deep water formation due to the strong vertical mixing in these regions. Away from deep water formation regions, the performance of the optimization with noisy data was still not satisfactory, possibly due to bad conditioning of the problem. The conditioning of the optimization and the difficulties due to the noise amplification are further discussed in part 2 of this work using real oceanographic data for the North Atlantic Ocean.

Tziperman, E., W.C. Thacker, R.B. Long, S.-M. Hwang, and S.R. Rintoul. Oceanic data analysis using a general circulation model, Part 2: A North Atlantic model. Journal of Physical Oceanography, 22(12):1458-1485 (1992).

A general circulation model (GCM) and North Atlantic climatological data of temperature, salinity, wind stress, evaporation minus precipitation, and air-sea heat fluxes are used to examine the possibility of solving inverse problems using a full-scale numerical GCM and real oceanographic data, combined through an optimization approach. In this study several solutions for the model inputs and the structure of the cost function as a function of the model inputs are examined to demonstrate two of the main difficulties confronting such large-scale nonlinear inverse problems (about 30,000 unknowns and a similar number of constraints for the problem examined here). The first is the possible existence of local minima of the cost function, which prevents the convergence of the optimization to the global minimum representing the desired optimal solution for the model inputs. The second difficulty, which seems the dominant one for many of the problems examined in this part as well as in part 1, is the ill conditioning of the inverse problem. Simple model equations are used to analyze the conditioning of the optimization problem and to analyze the role of both dissipation and waves in the model dynamics in conditioning the problem. The analysis suggests what might be an improved formulation of the cost function resulting in better conditioning of the problem. The relation between the optimization approach and the robust diagnostic method of Sarmiento and Bryan (1982) is explicitly demonstrated, and the solution obtained by combining the two methods is used to examine the performance of the GCM used here for the North Atlantic Ocean.

Velden, C.S., C.M. Hayden, W.P. Menzel, J.L. Franklin, and J.S. Lynch. The impact of satellite-derived winds on numerical hurricane track forecasting. Weather and Forecasting, 7(1):107-118 (1992).

While qualitative information from meteorological satellites has long been recognized as critical for monitoring tropical cyclone activity, quantitative data are required to improve the objective analysis and numerical weather prediction of these events. In this paper, results are presented that show that the inclusion of high-density, multispectral, satellite-derived information into the analysis of tropical cyclone environmental wind fields can effectively reduce the error of objective track forecasts. Two independent analysis and barotropic track-forecast systems are utilized in order to examine the consistency of the results. Both systems yield a 10%-23% reduction in middle- to long-range track-forecast errors with the inclusion of the satellite-wind observations.

Wanninkhof, R.H. Relationship between gas exchange and wind speed over the ocean. Journal of Geophysical Research,97(5):7373-7382 (1992).

Relationships between wind speed and gas transfer, combined with knowledge of the partial pressure difference of CO₂ across the air-sea interface are frequently used to determine the CO₂ flux between the ocean and the atmosphere. Little attention has been paid to the influence of variability in wind speed on the calculated gas transfer velocities and the possibility of chemical enhancement of CO₂ exchange at low wind speeds over the ocean. The effect of these parameters is illustrated using a quadratic dependence of gas exchange on wind speed which is fit through gas transfer velocities over the ocean determined by the natural-¹⁴C disequilibrium and the bomb-¹⁴C inventory methods. Some of the variability between different data sets can be accounted for by the suggested mechanisms, but much of the variation appears due to other causes. Possible causes for the large difference between two frequently-used relationships between gas transfer and wind speed are discussed. To determine fluxes of gases other than CO₂ across the air-water interface, the relevant expressions for gas transfer, and the temperature and salinity dependence of the Schmidt number and solubility of several gases of environmental interest, are included in an appendix.

Willis, P.T., J. Hallett, and R.A. Black. Cloud and hydrometeor microphysics at -3°C in a vigorous Florida convective updraft. Preprints, 11th International Conference on Clouds and Precipitation, Montreal, Canada, August 17-21, 1992. American Meteorological Society, Boston, 436-439 (1992).

No abstract.

Willoughby, H.E. Linear motion of a shallow-water barotropic vortex as an initial-value problem. Journal of the Atmospheric Sciences, 49(21):2015-2031 (1992).

This paper revisits calculation of motion for a shallow-water barotropic vortex with fixed mean axisymmetric structure. The algorithm marches the linear primitive equations for the wavenumber 1 asymmetry forward in time using a vortex motion extrapolated from previous calculations. Periodically, it examines the calculated asymmetry for the apparent asymmetry due to mispositioning of the vortex center, repositions the vortex to remove the apparent asymmetry, and passes the corrected vortex motion on to the next cycle. This approach differs from the author's earlier variational determination of the steady-state motion after initial transients had died away. The steady-state approach demonstrated that the vortex had normal modes at zero frequency and, when an annulus of weak anticyclonic flow encircled the cyclonic inner vortex, at the most anticyclonic rotation frequency of the mean flow. Forcing of the former model led to too rapid steady-state poleward motion on a beta plane. At least for the linear problem, the key to more realistic simulation of motion and structure is the normal modes' transient response to diverse forcing: environmental potential vorticity gradients, embedded sources and sinks of mass, and initial asymmetries. The beta effect and other environmental potential vorticity gradients excite the normal modes to induce an acceleration of the vortex center toward and to the left of the direction to maximum environmental vorticity. Times ~100 days would be required to reach the too fast motions predicted in the earlier work. A rotating mass source-sink pair drives the vortex along a cycloidal track, but does not force the normal modes. A nonrotating source-sink forces a motion from the source toward the sink and excites the normal modes, leading to motion that persists after the forcing has ceased. Similarly, initial asymmetries that project onto the normal modes maintain themselves for times >10 days, leading to persistent vortex propagation that evolves as the complex normal-mode frequencies dictate. Understanding of these normal modes can contribute to better tropical cyclone motion forecasts through better initialization of numerical track prediction models.

Wilson, W.D., and J.A. Routt. Shipboard acoustic Doppler current profiler data collected during the Subtropical Atlantic Climate Studies (STACS) Project (1989-1990). NOAA Technical Memorandum, ERL AOML-71 (PB93-116598), 147 pp. (1992).

The Subtropical Atlantic Climate Studies (STACS) Program of NOAA is directed at determining the role of ocean circulation in global atmospheric climate, providing data for numerical model verification, and developing monitoring strategies for climatically important circulation features. The initial emphasis of STACS was on the subtropics, where earlier studies suggested that oceanic heat flux in the Atlantic is a maximum. Results of an intensive two-year study of the Florida Current at 27°N provided data on its role in Atlantic circulation and oceanic heat flux. The study also provided a system for monitoring the current on a long-term basis.

Wooldridge, A.L., C.G.A. Harrison, M.A. Tivey, P.A. Rona, and H. Schouten. Magnetic modeling near selected areas of hydrothermal activity on the Mid-Atlantic and Gorda Ridges. Journal of Geophysical Research, 97:10,911-10,926 (1992).

Sea surface magnetic and bathymetric data from two areas of observed high-temperature hydrothermal activity in the Atlantic (trans-Atlantic geotraverse, or TAG hydrothermal field) and Pacific (Sea Cliff hydrothermal field) and two areas of inferred hydrothermal activity in the Atlantic (Mid-Atlantic Ridge [MAR] at 15°N and 17°N) were studied to determine the effect of vent activity on magnetization of the oceanic crust. All of the sites examined show a low in the magnetic anomaly in varying degrees. Magnetization lows within the axial marine magnetic anomaly have been associated with some areas of active and relict high-temperature hydrothermal venting. A three-dimensional magnetic inversion was performed on magnetic and bathymetric data from the TAG hydrothermal area on the Mid-Atlantic Ridge (26°N), and two-dimensional magnetic inversions were done on individual profiles from the other study sites. The map from the TAG area shows a "negative" in the crustal magnetization solution just to the east of the median valley axis which encompasses the active hydrothermal area. A low in magnetization continues up the eastern wall which suggests alteration of the crust. A distinct low in magnetization is present within the axial anomaly at the Sea Cliff hydrothermal field located on the eastern wall of the Gorda Ridge. The magnetization low becomes less pronounced farther south of the known vent field. Profiles from 15°N and 17°N on the Mid-Atlantic Ridge show magnetization lows over areas of inferred hydrothermal activity. These lows are present over the eastern and western walls of the median valley, respectively. The lows observed in the axial marine magnetic anomaly in these four study sites all occur slightly off axis, on crust that is at least 200,000 years old on the Mid-Atlantic Ridge and at least 100,000 years old on the Gorda Ridge. On the basis of magnetic modeling and measurements of rock magnetic properties, the most probable cause of the low in the magnetization is alteration of the oceanic crust with other subsidiary contributing factors which vary from site to site. The magnetization low over TAG is most probably due to high-temperature hydrothermal alteration of the crust and a thinner layer 2, with possible contributions from reversal events and magma chamber/Curie isotherm effects. The low near the Sea Cliff hydrothermal field on the Gorda Ridge is probably the product of tectonically-controlled, low-temperature (non-hydrothermal) alteration, high-temperature hydrothermal alteration, and magnetic reversal events. At 15°N and 17°N on the MAR, the lows may be produced by alteration of the crust due to possible hydrothermal activity. **1991**

Aberson, S.D., and M. DeMaria. A nested barotropic hurricane track forecast model (VICBAR). Preprints, 19th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 6-10, 1991. American Meteorological Society, Boston, 81-86 (1991).

No abstract.

Baik, J.-J., M. DeMaria, and S. Raman. Observational evidence for upper tropospheric asymmetric eddy momentum forcing and subsequent intensity change. Preprints, 19th Conference on Hurricane and Tropical Meteorology, Miami, FL, May 6-10, 1991. American Meteorological Society, Boston, 478-481 (1991).

No abstract.

Baik, J.-J., M. DeMaria, and S. Raman. Tropical cyclone simulations with the Betts convective adjustment scheme. Part III: Comparisons with the Kuo parameterization. Monthly Weather Review, 119(12):2889-2899 (1991).

Numerical simulations of tropical cyclones in an axisymmetric model with the Betts convective adjustment scheme and the 1974 Kuo cumulus parameterization are compared. It is shown that the storm with the Betts scheme has a slightly more intense mature stage than the storm with the Kuo scheme. For both schemes, the parameterized heating is dominant initially, while the grid-scale heating is dominant at the mature stage. The storms begin to intensify rapidly when the grid-scale heating extends through a deep layer. The Betts scheme is more effective at removing water vapor and delays the onset of grid-scale heating. This results in later development of the storm with the Betts scheme. The storm evolution with both the Betts and Kuo schemes is sensitive to the treatment of the evaporation of liquid water in the grid-scale condensation scheme. This suggests that a prognostic equation for liquid water should be used when simulating tropical cyclones with a model resolution fine enough for grid-scale heating to be important.

Barnes, G.M., and M.D. Powell. The inflow thermodynamics of Hurricane Gilbert. Preprints, 19th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 6-10, 1991. American Meteorological Society, Boston, 486-489 (1991).

No abstract.

Barnes, G.M., J.F. Gamache, M.A. LeMone, and G.J. Stossmeister. A convective cell in a hurricane rainband. Monthly Weather Review, 119(3):776-794 (1991).

On 10 October 1983 the two NOAA WP-3D aircraft completed a mision designed to provide airborne Doppler radar data for a convective cell embedded in a weak rainband on the trailing side of Hurricane Raymond. Comparisons of the wind field produced from the pseudo-dual Doppler radar technique with in-situ wind measurements suggest that the larger convective-scale features may be resolved if the sampling time is kept to a minimum. The convective cell was found to move downband faster than any environmental winds, but slightly slower than the winds found in the reflectivity core that delineates the cell. In the core of the cell the tangential wind is increased and the radial inflow turns to outflow with respect to the circulation center. The flow field demonstrates that the downband stratiform portion of a rainband is not from cells currently active, since the updraft detrains upwind relative to the cell, but rather it is due to the fallout from ice particles placed into the upper troposphere by clouds that have since dissipated. The mass flux of this cell is estimated to be 5%-10% of the mass flux accomplished by an eyewall of a moderate tropical cyclone. This finding supports the concept that large, convective-active rainbands have a major effect on the subcloud layer air flowing toward the eyewall.

Beryulev, G.P., P.B. Black, and A.V. Litinetski. Intercomparison of wind and temperature data from the research aircraft WP-3D and AN-12BC in Hurricane Gilbert, 1988. Preprints, 19th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 6-10, 1991. American Meteorological Society, Boston, 587-588 (1991).

No abstract.

Black, M.L., R.W. Burpee, and F.D. Marks. Vertical motions in tropical cyclones determined with airborne Doppler radial velocities. Preprints, 19th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 6-10, 1991. American Meteorological Society, Boston, 409-411 (1991).

No abstract.

Black, P.B., and F.D. Marks. The structure of an eyewall meso-vortex in Hurricane Hugo (1989). Preprints, 19th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 6-10, 1991. American Meteorological Society, Boston, 579-582 (1991).

No abstract.

Broecker, W.S., A. Virgilio, and T.-H. Peng. Radiocarbon age of the deep Atlantic revisited. Geophysical Research Letters, 18(1):1-3 (1991).

No abstract.

Brown, M.G., F.D. Tappert, and G.J. Goni. An investigation of sound ray dynamics in the ocean volume using an area preserving mapping. Wave Motion, 14(1):93-99 (1991).

An area preserving mapping which describes sound ray propagation in a simple range-dependent model of the ocean sound channel is derived and studied. The unbounded ocean model has a bilinear sound speed profile in which the vertical sound speed gradient above the sound channel axis varies sinusoidally in range. It is assumed that the scale of the range-dependent perturbation is small compared to a typical upper loop length of a ray. The explicit mapping which results gives successive iterates of range and upgoing ray angle at the sound channel axis (r_n, theta_n) - (r_n+1, theta_n+1). The degree of stochasticity of the mapping is governed by a single dimensionless parameter, epsilon, the strength of the range-dependent perturbation. Iterates of the mapping indicate that some ray trajectories are chaotic (i.e., exhibit extreme sensitivity to initial conditions) for perturbations comparable in strength to those produced by internal waves in the ocean. The chaotic nature of these rays is confirmed by the calculation of positive Lyapunov exponents.

Burpee, R.W., and P.G. Black. Strong surface winds and mesoscale convective systems in the unnamed tropical storm of 1987. Preprints, 19th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 6-10, 1991. American Meteorological Society, Boston, 412-415 (1991).

No abstract.

Burpee, R.W., J.S. Griffin, J.L. Franklin, and F.D. Marks. Airborne analysis of observations from a NOAA P-3 in support of operational hurricane forecasting. Preprints, 7th International Conference on Interactive Information and Processing Systems for Meteorology, Oceanography, and Hydrology, New Orleans, LA, January 13-18, 1991. American Meteorological Society, Boston, 195-197 (1991).

No abstract.

Burpee, R.W., J.S. Griffin, J.L. Franklin, and F.D. Marks. Airborne analysis of observations from a P-3 aircraft in support of operational hurricane forecasting. Proceedings, 4th Interagency Airborne Geoscience Workshop, La Jolla, CA, January 29-February 1, 1991. NASA, Washington, D.C., 123-124 (1991).

No abstract.

Carsey, T.P. Marine tropospheric hydrocarbons: An intercomparison exercise. NOAA Data Report, ERL AOML-21 (PB91-223735), 31 pp. (1991).

Results from an multi-laboratory intercomparison exercise for the determination of non-methane hydrocarbons in the North Pacific troposphere are presented. Each of the ten participating laboratories analyzed marine air obtained on the NOAA ship R/V Researcher and from a single large tank of Oregon coastal air for some or all of the following: ethane, ethylene, propane, propene, isobutane, n-butane, acetylene, 1-butene, isobutene (2-methyl-1-propene), cis-2-butene, trans-2-butene, iso-pentane, n-pentane, isopentene (2-methyl-1-butene), 1-pentene, benzene, toluene, methane, carbon dioxide, and methyl chloroform. The following parameters were computed where data was sufficient for each laboratory and each analyte: mean mixing ratios, total (sampling plus analytical) precision, analytical precision, and sampling precision. Means were compared using a non-parametric procedure. Mixing ratio versus time data for the various compounds indicated that diurnal changes were minimal or absent; however, slight decreases in mixing ratios were observed for C₂H₆, C₂H₂, CH₃CCl₃, CO and CH₄.

Charlou, J.L., H. Bougault, P. Appriou, T.A. Nelsen, and P.A. Rona. Different TDM/CH₄ hydrothermal plume signatures: TAG site 26°N and serpentinized ultrabasic diapir at 15°05'N on the Mid-Atlantic Ridge. Geochimica et Cosmochimica Acta, 55(12):3209-3222 (1991).

As a part of the 1988 NOAA VENTS Program, CH₄ and Mn tracers were used to identify and compare hydrothermal plumes found above the TAG field (26°N) and in the rift valley at 15°N close to the eastern intersection of the ridge axis with the 15°20'N Fracture Zone at the Mid-Atlantic Ridge (MAR). Active hydrothermal venting was confirmed at TAG, based on elevated concentrations of total dissolved Mn (TDM up to 30 nmol/kg), high CH₄ concentrations (up to 200 nL/L), and elevated nephelometry signals. Plumes of a different composition were identified at 15°N with high CH₄ concentrations (up to 400 nL/L), low total dissolved Mn concentrations (TDM <1 nmol/kg), and no significant nephelometry signal. The different properties of these tracers and the different tracer ratios can be used to deduce vent fluid characteristics and compare one hydrothermal area to another. TDM/CH₄ and nephel/CH₄ ratios at TAG are of the same order of magnitude as those observed at other spreading axis hydrothermal fields. At 15°N, the low TDM/CH₄ ratio provides evidence of fluid circulation into ultrabasic rocks and offers a potentially useful and single method of exploring for hydrothermal activity associated with serpentinization. Mantle degassing through hydrothermal activity associated with serpentinization is an important process with respect to chemical and thermal exchanges between the upper mantle and the ocean. Different ratios of hydrothermal tracers (i.e., TDM/CH₄) provide a useful framework for identifying subseafloor processes along mid-oceanic ridges.

Chew, F., and M.H. Bushnell. Geostrophic departure, local turning, speed change, and eddy flux: A new perspective. Journal of Physical Oceanography, 21(11):1684-1689 (1991).

Conjunctions of meander passages and cross-stream eddy momentum fluxes are common in western boundary currents. To explore the mechanism linking them, we offer a diagnostic equation of their time-dependent motions. The equation is embodied in the more explicit form of a hodograph with two characteristics: a tilt and a veering/backing. The veering/backing is in response to the changing geostrophic departure, and the tilt to the change in the speed of the flow, which can be zero, positive, or negative. This direct approach to the kinematic fieldits pattern and its changeled to a hypothesis on the linkage that the cross-stream eddy momentum flux is driven by the downstream pressure gradient force in the supergeostrophic segment of the meandering flow.

Cione, J.J., S. Raman, and L.J. Pietrafesa. Effects of marine boundary layer baroclinicity induced by the Gulf Stream on east coast winter storms. Preprints, 5th Conference on Meteorology and Oceanography of the Coastal Zone, Miami, Florida, May 6-9, 1991. American Meteorological Society, Boston, 113-117 (1991).

No abstract.

Dammann, W.P., and J.R. Proni. Sediment plume measurements with an acoustic concentration profiler, pp. 311-345. In Report 1: Dredged Material Plume Survey Data Report, N.C. Kraus (ed.). Technical Report DRP-91-3, U.S. Army Corps of Engineers, 352 pp. (1991).

No abstract.

Dammann, W.P., J.R. Proni, J.F. Craynock, and R. Fergen. Oceanic wastewater outfall plume characteristics measured acoustically. Chemistry and Ecology, 5(1-2):75-84 (1991).

A study, called SEFLOE, of the dispersion characteristics of several wastewater outfalls was conducted off the coast of southeast Florida (USA). In this study, the feasibility of utilizing high frequency (20 kHz and 200 kHz) acoustic echoes to characterize the dilution characteristics of the effluent wastewater was examined. It is hypothesized that the background corrected acoustic backscattered intensity may be used to guide chemical/biological sampling, and that one or more plume subfields may be revealed by the scattering strength field. Data from SEFLOE have indicated that the wastewater plume field is divided into regions of higher concentration spatially separated by regions of lower concentration; we call these regions of higher concentration "boluses." When the water column is density stratified, subsurface plumes may peel off of the main rising plume and remain at equilibrium on a density gradient.

DeMaria, M., and R.W. Jones. Optimization of a hurricane track forecast model using the adjoint model equations. Preprints, 9th Conference on Numerical Weather Prediction, Denver, CO, October 14-18, 1991. American Meteorological Society, Boston, 547-550 (1991).

No abstract.

DeMaria, M., and J. Kaplan. A statistical model for predicting tropical cyclone intensity change. Preprints, 19th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 6-10, 1991. American Meteorological Society, Boston, 521-525 (1991).

No abstract.

Dodge, P.P., R.W. Burpee, and F.D. Marks. Airborne Doppler radar analyses of the core of Hurricane Gilbert. Preprints, 19th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 6-10, 1991. American Meteorological Society, Boston, 551-552 (1991).

No abstract.

Enfield, D.B. Book review, "Study in geophysics: Sea level change." Bulletin of the American Meteorological Society, 72(8):1282-1283 (1991).

No abstract.

Enfield, D.B., and L. Cid. Low-frequency changes in El Niño-Southern Oscillation. Journal of Climate, 4(12):1137-1146 (1991).

Although there are indications from numerical models that El Niño-Southern Oscillation (ENSO) may be an internal mode of the coupled Pacific Ocean/atmosphere system, sensitive to climatic background parameters, it has not yet been possible to find significant changes in ENSO variability between the Little Ice Age and the present. Yet, a number of authors have found qualitative indications in anecdotal and proxy records of shorter, century-scale variations in the return-interval statistics for El Niño episodes. To objectively determine what nonstationarities exist, we statistically examine the El Niño occurrences since 1525, compiled by Quinn et al. (1987). We have stratified the return intervals both for strong events and for all events according to two null hypotheses: (1) return intervals are stationary over periods of 200-500 years; and (2) the intervals are stationary on a centenary time scale, between epochs of contrasting solar variability. Two-parameter Weibull distributions are fit to subsamples of the data using an optimized bootstrap procedure, and the scale parameters are compared between groups. At the 95% significance level, only the null hypothesis for high/low solar levels and strong El Niño events can be rejected. The corresponding hypothesis for all events rejects at the 90% level, while overall stationarity cannot be rejected at any reasonable level, for either class of events. The significant results are that: (a) the El Niño recurrence rate is stationary with respect to long-term climate changes; (b) return intervals of strong El Niño events are significantly nonstationary at centenary time scales; and (c) events of all intensities exhibit the same nonstationarity but less clearly. There is too little data to reject the possibility that the association with solar epochs is coincidental; however, we have advanced this hypothesis to explain such a connection.

Feuer, S.E., and J.L. Franklin. Nested analyses of Hurricane Gloria from dropwindsonde and Doppler radar data. Preprints, 19th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 6-10, 1991. American Meteorological Society, Boston, 130-133 (1991).

No abstract.

Franklin, J.L., and M. DeMaria. The impact of Omega dropwindsonde data on hurricane track forecasts using the VICBAR model. Preprints, 9th Conference on Numerical Weather Prediction, Denver, CO, October 14-18, 1991. American Meteorological Society, Boston, 404-407 (1991).

No abstract.

Franklin, J.L., M. DeMaria, and C.S. Velden. The impact of Omega dropwindsonde and satellite data on hurricane track forecasts using the VICBAR model. Preprints, 19th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 6-10, 1991. American Meteorological Society, Boston, 87-92 (1991).

No abstract.

Frazel, D.W., G.A. Berberian, J. McElroy, and G.L. Hitchcock. Radiatively Important Trace Species (RITS) 1990: Tropical Pacific Ozone Minimum Expedition--nutrient, chlorophyll-a, and primary productivity data. NOAA Data Report, ERL AOML-19 (PB91-178087), 40 pp. (1991).

During the period of January 3-February 18, 1990, a multifaceted oceanographic research cruise called the RITS 1990 Tropical Pacific Ozone Minimum Expedition was made on the NOAA ship Malcolm Baldrige in the equatorial Pacific Ocean. The objective of the cruise was to study processes controlling radiatively important trace species in the region of the tropical Pacific ozone minimum in the central equatorial Pacific Ocean. Measurements from hydrocasts for nutrients, phytoplankton biomass, and primary productivity were made during this period. This report represents the hydrographic, nutrient, and biological data from this cruise.

Gamache, J.F. Inner core budget studies of Hurricane Norbert (1984). Preprints, 19th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 6-10, 1991. American Meteorological Society, Boston, 545-550 (1991).

No abstract.

Gamache, J.F., F. Roux, and F.D. Marks. Comparison of three methods to deduce three-dimensional wind fields in a hurricane with airborne Doppler radar. Preprints, 25th International Conference on Radar Meteorology, Paris, France, June 24-28, 1991. American Meteorological Society, Boston, 462-465 (1991).

No abstract.

Goni, G.J. Chaos in underwater acoustics. In Ocean Variability and Acoustic Propagation, J. Potter and A. Warn-Varnas (eds.). Kluwer Academic Publishers, The Netherlands, 139-160 (1991).

No abstract.

Gray, W.M., C.W. Landsea, P.W. Mielke, and K.J. Berry. Potential forecast skill for Atlantic seasonal hurricane variability. Preprints, 19th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 6-10, 1991. American Meteorological Society, Boston, 89-95 (1991).

No abstract.

Gray, W.M., C.W. Landsea, P.W. Mielke, and K.J. Berry. Strong extended range seasonal predictive potential for Atlantic hurricane activity. Proceedings, 16th Annual Climate Diagnostics Workshop, Los Angeles, CA. NOAA, 412-416 (1991).

No abstract.

Griffin, J.S., R.W. Burpee, J.L. Franklin, and F.D. Marks. Preliminary results of airborne analysis of observations in support of operational hurricane forecasting. Preprints, 19th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 6-10, 1991. American Meteorological Society, Boston, 144-147 (1991).

No abstract.

Hannington, M., P. Herzig, S. Scott, G. Thompson, and P.A. Rona. Comparative mineralogy and geochemistry of gold-bearing sulfide deposits on the mid-ocean ridges. Marine Geology, 101(1-4):217-248 (1991).

A comparative study of the mineralogy and geochemistry of sulfide deposits on mid-ocean ridges in the northeast Pacific and the Mid-Atlantic reveals common characteristics associated with primary gold enrichment. Average gold contents of 0.8 to 5 ppm Au occur in sulfides from Southern Explorer Ridge and Axial Seamount (northeast Pacific) and from the TAG hydrothermal field and Snakepit vent field (Mid-Atlantic Ridge). The enrichment of gold in these deposits is consistently related to a phase of late-stage, low-temperature (<300°C) venting. Concentrations >1 ppm Au occur exclusively in pyritic assemblages and commonly with abundant Fe-poor sphalerite and a suite of complex Pb-Sb-As sulfosalts. Amorphous silica and, locally, barite or carbonate, are important constituents of the gold-rich precipitates, but do not contain gold themselves. High-temperature (350°C), black-smoker assemblages, consisting dominantly of pyrite, chalcopyrite, pyrrhotite, isocubanite, and abundant anhydrite, are uniformly gold-poor (<0.2 ppm Au). To the extent that individual sulfides can be mechanically separated, chemical analyses by neutron activation indicate that gold is most abundant in sphalerite (up to 5.7 ppm Au), but also occurs in pyrite and marcasite. Samples of sphalerite with abundant inclusions of fine-grained sulfosalts locally contain up to 18 ppm Au, suggesting that the sulfosalts may be the repositories for gold. No free gold has been observed at 4,000 x magnification of polished specimens, indicating that the gold is present only as submicroscopic inclusions or as a chemical constituent within the sulfides. Samples from gold-rich deposits in the northeast Pacific and Mid-Atlantic are compared with similar but relatively gold-poor sulfides from the Galapagos Rift and 13°N on the East Pacific Rise (EPR), and with barren sulfides from 11°N EPR, 21°N EPR, the Endeavour Ridge, and the Southern Juan de Fuca Ridge. Trace element analyses of more than 170 samples show that gold enrichment in almost all of the deposits is associated with high concentrations of Ag, As, Sb, Pb, and Zn, and locally with high Cd, Hg, Tl, and Ga. In contrast, gold is typically depleted in samples with high Co, Se, and Mo. The close association of Au with Ag, As, Sb, and Pb may reflect the common behavior of these metals as aqueous sulfur complexes (e.g., [Au(HS)₂-]) at low temperatures. Similar mineralogical and geochemical associations are observed in sulfide deposits from modern back-arc settings and in the ancient geologic record.

Hansen, D.V., and G.A. Maul. Anticyclonic current rings in the eastern tropical Pacific Ocean. Journal of Geophysical Research, 96(C4):6965-6979 (1991).

Observations from satellite-tracked drifting buoys, XBT and CTD data, and GEOSAT altimeter data are used to describe anticyclonic eddies that occur in small numbers off the Pacific coast of Central America. These eddies are similar in many respects to the well-known, warm-core rings that are observed north of the Gulf Stream off the Atlantic coast of North America, except that they occur in an environment that also is warm, and they contain considerably greater kinetic energy. It is hypothesized that they are formed as a result of conservation of potential vorticity when the North Equatorial Countercurrent (NECC) turns northward upon approaching the eastern boundary during its autumnal maximum. The rings so formed have a strongly nonlinear character which causes them to propagate westward between 9°N and 14°N with a speed in excess of that of long Rossby waves. Due to a relatively small available potential energy content, these rings have a dissipation time scale of about six months and perhaps end by collision with and reabsorption into the NECC. The rings account for the observed enhancement of surface kinetic energy, and probably for the seaward transport of waters enriched in copper.

Hanson, K., and G.A. Maul. Florida precipitation and the Pacific El Ni�o, 1895-1989. Florida Scientist, 54(3/4):160-168 (1991).

This study identifies rainfall anomalies, timed with major El Ni�o events, in seven climatic divisions of Florida. The study also determines the statistical significance of these rainfall anomalies. The seasonal and annual climatology of rainfall is presented for seven climatic divisions of the State for the period 1895-1989. Periodogram analysis indicates five- to six-year variability in rainfall throughout most of Florida, in particular, during winter and spring. Superposed epoch analysis, utilizing only rainfall during the year prior to and concurrent with a major El Ni�o, shows that Statewide rainfall anomalies are timed with these Pacific events. The most significant anomalies are: (1) below normal rainfall over all of the State during winter and spring the year prior to an El Ni�o; and (2) above normal rainfall over all of the State during winter and spring the second year of an El Ni�o. Largest rainfall anomalies have occurred in the southern climatic divisions of Florida. During winters of the second year of El Ni�o, south Florida rainfall anomalies range from +76 to +94 mm (+3.0 to + 3.7 inches) depending on the climatic division. These anomalies are 45% to 66% above normal winter rainfall, and are significant at the 0.999 level.

Herzig, P.M., M.D. Hannington, S.D. Scott, G. Maliotis, P.A. Rona, and G. Thompson. Gold-rich seafloor gossans in the Troodos ophiolite and on the Mid-Atlantic Ridge. Economic Geology, 86(8):1747-1755 (1991).

No abstract.

Houston, S.H., and M.D. Powell. Effects of Tropical Storm Marco (1990) on Florida's west coast. Preprints, 5th Conference on Meteorology and Oceanography of the Coastal Zone, Miami, FL, May 6-9, 1991. American Meteorological Society, Boston, 131-133 (1991).

No abstract.

Jones, R.W., and M. DeMaria. A variational method for including persistence in a hurricane track forecast model. Preprints, 19th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 6-10, 1991. American Meteorological Society, Boston, 331-334 (1991).

No abstract.

Kaplan, J., and J.L. Franklin. The relationship between the motion of Tropical Storm Florence (1988) and its environmental flow. Preprints, 19th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 6-10, 1991. American Meteorological Society, Boston, 93-97 (1991).

No abstract.

Lagos, P., D.V. Hansen, and A. Herman. Climatological atlas of the subsurface thermal structure of the eastern tropical South Pacific Ocean. NOAA Technical Report, ERL 444-AOML-34, 303 pp. (1991).

Monthly climatological maps of objectively analyzed fields of temperature are presented at standard oceanographic observation levels from the surface to 300 m depth on a 1° latitude-longitude grid in the region between the equator and 20°S and between the South American coast and 90°W. The temperature data used in this study were from bathythermograph measurements obtained from 1952 to 1987 from Peruvian and other research vessels; they were made available by research institutions in Peru and the United States and by the National Oceanographic Data Center and the Fleet Numerical Oceanographic Center. The data set was blended with recent data to form a data base containing 14,000 observations. The method of analysis consists of optimally interpolating the value at each mapping grid point, using observations taken at known nearby locations. This method, known as Kriging, is a best linear unbiased estimator that also yields an estimate of the uncertainty of each interpolated value. A brief discussion of the major characteristic features of the temperature fields is given, including a comparison of the SST results with results from other SST climatologies.

Landsea, C.W. Intense Atlantic hurricanes and their concurrent/predictive relationships to west African rainfall. Preprintts, 19th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 6-10, 1991. American Meteorological Society, Boston, 165-169 (1991).

No abstract.

Landsea, C.W. West African monsoonal rainfall and intense hurricane associations. Colorado State University, Department of Atmospheric Science Paper No. 484, 272 pp. (1991).

No abstract.

Landsea, C.W., and W.M. Gray. Concurrent multidecadal variations of west African monsoonal rainfall and intense Atlantic hurricane activity. Preprints, 5th Conference on Climate Variations, Denver, CO. American Meteorological Society, Boston, 38-41 (1991).

No abstract.

Landsea, C.W., and W.M. Gray. Predictability of intense Atlantic hurricanes and western Sahel rainfall from west African rainfall. Proceedings, 16th Annual Climate Diagnostics Workshop, Los Angeles, CA. NOAA, 417-422 (1991).

No abstract.

Lee, W.-C., and F.D. Marks. Real-time display of mean three-dimensional hurricane structure using the VTD technique. Preprints, 25th International Conference on Radar Meteorology, Paris, France, June 24-28, 1991. American Meteorological Society, Boston, 470-473 (1991).

No abstract.

Lee, W.-C., F.D. Marks, and R. Carbone. Real-time display of mean three-dimensional hurricane structure using the VTD technique. Preprints, 19th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 6-10, 1991. American Meteorological Society, Boston, 445-450 (1991).

No abstract.

Lhermitte, R., and P.T. Willis. Small Doppler radar as a precipitation gauge. Preprints, 25th International Conference on Radar Meteorology, Paris, France, June 24-28, 1991. American Meteorological Society, Boston, 790-792 (1991).

No abstract.

Marks, F.D., and R.A. Houze. Kinematic structure of the eyewall of Hurricane Emily (1987) as determined from an airborne Doppler radar. Preprints, 19th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 6-10, 1991. American Meteorological Society, Boston, 437-440 (1991).

No abstract.

Marks, F.D., D. Atlas, and P.T. Willis. Probability matched Z-R relations for hurricanes from aircraft observations. Preprints, 25th International Conference on Radar Meteorology, Paris, France, June 24-28, 1991. American Meteorological Society, Boston, 778-781 (1991).

No abstract.

Maul, G.A. INSMAP 1990: The Second International Symposium on Marine Positioning. Bulletin Geodesique, 65(1):3-4 (1991).

No abstract.

Maul, G.A., and K.J. Hanson. Interannual coherence between North Atlantic atmospheric surface pressure and composite southern United States sea level. Geophysical Research Letters, 18(4):653-656 (1991).

Annual mean sea levels along the southern United States have been examined for interannual variability. Fifteen sea level stations from Cape Hatteras to the Rio Grande that best covered the three lunar nodal cycles from 1931-1987 were selected for analysis. Linear trends, ranging from +0.2 cm/yr to +1.4 cm/yr, were subtracted from their respective series, leaving remarkably similar residuals. The composite time series of the 15 residuals was compared with time series of surface air pressure over the North Atlantic Ocean during the period 1947-1987. The best correlation is a negative relationship between composite sea level and wintertime air pressure north of 45°N, and a positive relationship from 20°N-45°N. The most significant correlations (-0.73 and +0.51) were found for 60°N, 20°W, and for 30°N, 25°W, respectively. Wintertime meridional air pressure gradients between these two latitudes represents about 50% of the variance in composite annual mean sea level. Both the sea level and air pressure time series had significant spectral peaks at 13.3 and 4.4 years, with about 52% of the covariance coming from these two periods.

Maul, G.A., S.R. Baig, and M.H. Bushnell. Nowcasting cross-stream profiles of ocean surface current in the Straits of Florida. Journal of Atmospheric and Oceanic Technology, 8(1):179-185 (1991).

Cross-stream profiles of ocean surface currents between Florida and the Bahamas are highly correlated with the cross-stream-averaged current. When the cross-stream averaged speed is high, the speed axis of the Florida Current is to the west, and when the cross-stream-averaged speed is low, the speed axis is near the center of the Straits. Since sea level and weather along the Florida coast are routinely used to nowcast cross-stream-averaged speed, nowcasts of cross-stream surface current profiles and location of the speed axis can also be routinely reported. An improved algorithm using cross-stream sea level difference and local weather, and a description of the revised NOAA Gulf Stream product from the National Hurricane Center, are presented.

Mayer, D.A., and G.A. Maul. Refinement of the statistical relationship between Straits of Florida sea level difference and Florida-Bahamas cable voltages. Journal of Geophysical Research, 96(C3):4971-4972 (1991).

Analyses of a composite 6.5-year record of Bahamas minus Miami sea level difference (SLD) and Florida-Bahamas volume transport determined from submarine cable voltages (CABLE) support the hypothesis advanced by Maul et al. (1990) that SLD is the better variable for monitoring volume transport than western side sea level alone. In the subseasonal frequency band BW1 (393^-1-182^-1 cycles per day), modeled CABLE, when using SLD, accounts for 79% of the variance of observed CABLE. Further, the phase relationships of modeled CABLE with respect to SLD in BW1 represent approximately a simple time shift in that SLD leads CABLE by a little more than two weeks.

McLeish, W., and G.A. Maul. An ocean eddy off Miami. Proceedings, 5th Conference on Meteorology and Oceanography of the Coastal Zone, Miami, FL, May 6-9, 1991. American Meteorological Society, Boston, 94-97 (1991).

No abstract.

McLeish, W., and G.A. Maul. CODAR in the Straits of Florida: Final Report. NOAA Technical Report, ERL 447-AOML-35 (PB92-129964), 53 pp. (1991).

The Atlantic Oceanographic and Meteorological Laboratory (AOML) operated a Coastal Ocean Dynamics Applications Radar (CODAR) from 1986 through 1988 in a project to measure ocean surface currents near Miami and produce a series of maps of ocean surface current vectors. The project, CODAR in the Straits of Florida, also evaluated the feasibility and value of routine operational use of this HF radar system. The CODAR system produced many excellent maps that showed the west and central portions of the Florida Current. The core speed of this rapid flow, its distance offshore, and the often sharp decrease in speed nearshore were apparent. In addition, the maps showed at times a band of water nearshore that was moving slowly southward along the coast, and sometimes a cyclonic eddy about 15 km in diameter that was centered in a nearly fixed location 20 km northeast of Miami. However, on the whole this CODAR system could not be used as the project planned. The system required excessively frequent maintenance to remain online. More significantly, the maps produced were inadequate for the intended uses, and too many maps were missing. The maps frequently contained too few current vectors, and without further computer editing, many of the vectors that did appear were grossly incorrect. With added direction editing, major features of the circulation were omitted, and even fewer vectors remained on the maps. Examination of several CODAR maps and the calculated data from which they were produced showed certain limitations of the contractor-supplied data analysis procedure. Various interferences in the antenna voltage readings led to erratic radial velocity readings. In addition, the type of radial velocity combining procedure used was inaccurate with the sometimes erratic data. The concept of a fully automatic system to produce valid CODAR results was not realized in the version of the CODAR system that the project evaluated. In a suggested alternative calculation technique, the assimilation of CODAR data into a numerical model should result in many more maps with few missing data points in the coverage area. This CODAR system might then furnish results equivalent to those from several previous studies that gave valuable information on ocean circulations.

McPhaden, M.J., D.V.Hansen, and P.L. Richardson. A comparison of ship drift, drifting buoy, and current meter mooring velocities in the Pacific South Equatorial Current. Journal of Geophysical Research, 96(C1):775-781 (1991).

In this note we compare mean seasonal cycles of zonal and meridional velocity in the Pacific South Equatorial Current based on current meter mooring data, drifting buoy data, and ship drift data. Monthly averages of ship drift and drifting buoy data were computed over 2° latitude by 10° longitude rectangles centered at the positions of multiyear current meter moorings near 0°, 110°W, and 0°, 140°. All three representations of the flow field show the basic character of the annual mean and its variations, provided that the sampling characteristics associated with each measurement technique are taken into account. In particular, we find that more than 15 days of drifter data (regardless of year) are required on a 2° latitude by 10° longitude basis to produce monthly mean estimates that agree with moored estimates to within about 5-10 cm s^-1 rms. We also infer that windage affects climatological monthly mean ship drift velocities, although uncertainties in the data limit a precise determination of the windage magnitude. An upper bound appears to be about 3% of the surface wind speed, though the actual effect of windage may be considerably smaller.

Moody, J.L., A.A.P. Pszenny, A. Gaudry, W.C. Keene, J.N. Galloway, and G. Polian. Precipitation composition and its variability in the Southern Indian Ocean: Amsterdam Island, 1980-1987. Journal of Geophysical Research, 96(D11):20,769-20,786 (1991).

Event precipitation samples have been collected on Amsterdam Island (37°47'S, 77°31'E) from May 1980 through January 1987 and analyzed for SO₄⁼, NO₃^-, C Gamma , Na⁺, Mg⁺⁺, K⁺, Ca⁺⁺, H⁺, HCOO_t, and CH₃COO_t. The objective of this paper is to assess the processes which influence variability in the chemical composition of precipitation at this remote marine site. Back trajectories and gas phase ²²²Rn measurements were used to identify source regions and their relative contributions to precipitation composition. The technique of cluster analysis was applied to trajectory data as a method for determining to what degree different atmospheric flow patterns influence variability in the observed composition. The dominant source regions for chemical deposition were found to be Madagascar and/or southeast Africa and the ocean region north and east of Amsterdam Island. A strong seasonal signal in the precipitation composition is illustrated. Processes which influence variability in the chemical composition include the following: seasonality in the source strength of biogenic precursors for non-sea-salt (nss) SO₄⁼, NH₄⁺ and carboxylic acids; seasonality in biomass-burning continental sources for the concentration of NO₃^- and a portion of nss C Gamma; and variations in source region driven by daily changes in meteorology, as well as seasonal and annual differences in transport and removal patterns. In addition, interannual differences in nss SO₄⁼ concentration appear to be related to fluctuations in large-scale circulation patterns as defined by the Southern Oscillation.

Nelsen, T.A., and E.B. Forde. The structure, mass, and interactions of the hydrothermal plumes at 26°N on the Mid-Atlantic Ridge. Earth and Planetary Science Letters, 106(1-4):1-16 (1991).

Water-column surveys by combined nephelometer/CTD (NCTD) tows contributed to the 1985 discovery of the first black smokers on the Mid-Atlantic Ridge. Subsequent regional water-column mapping has helped define the extent, mass, and interactions of the suspended particulate matter phase (SPM) of the hydrothermal plumes emanating from the known and other nearby sources. The results of 29 NCTD cast/tows, covering 23-30 km² of ridge segment, indicate the presence of as many as two additional sources based on SPM concentration gradients and plume-top doming over source areas. Plume doming, documented here for the first time from field observations, conforms strikingly with laboratory experiments and can serve as a marker for source field location. A comparison of the plumes' SPM with potential temperature and salinity distributions indicates close correlation in water-column anomaly patterns for each, confirming modification of the regional potential temperature and salinity structure for hydrothermal plumes, which is expressed by wide separation and sloping of isotherms and isohalines.

Oxburgh, R., W.S. Broecker, and R.H. Wanninkhof. The carbon budget of Mono Lake. Global Biogeochemical Cycles, 5:359-372 (1991).

Radiocarbon measurements suggest that ¹⁴C-free carbon enters from beneath Mono Lake at a rate of about 1 mol/m²/yr. An input of this magnitude should be manifested in the inorganic carbon budget of the lake and, with this in mind, we have devised a model to reconstruct the evolution of the partial pressure of CO₂ (pCO₂) over the past 150 years. This encompasses a period (1945 to present) during which major diversions of source water via the Los Angeles aqueduct have been in effect, significantly increasing the salinity of the lake and, hence, its pCO₂. The model has been constrained by experimental characterization of the carbonate chemistry of the lake water, by the temperature dependence of pCO₂ for the lake water, and by pCO₂ measurements made on the lake water in 1966, 1969, 1981, and 1989. Our calculations suggest that prior to 1945 the pCO₂ of about 3.3 mol/m²/yr is required. Volcanic activity beneath the lake is a probable source of this input.

Palmer, D.R., T.M. Georges, and R.M. Jones. Classical chaos and the sensitivity of the acoustic field to small-scale ocean structure. Computer Physics Communications, 65:219-233 (1991).

Ray theory is usually the basis of data inversion schemes for acoustic remote sensing of the ocean. Chaotic ray paths are expected to be present whenever the ocean environment possesses small-scale, range-dependent structure. We are studying the implications of their presence for data inversion schemes. Using numerical simulations we consider ray-path characteristics for acoustic remote sensing of the Florida Current. We find small-scale bathymetric structure results in chaotic ray paths and an exponential proliferation of eigenrays. As a result, for each feature in the time-of-arrival pattern, there is associated not a single eigenray but a group, thereby limiting the spatial resolution of a remote sensing system.

Peng, T.-H. Indication of changes in ocean ventilation rates in ¹⁴C/¹²C record of tree-ring and of deep sea sediment. Proceedings, Interaction of the Global Carbon and Climate Systems Symposium, Lake Arrowhead, California, October 24-28, 1988. University of California, 15-1-15-12 (1991).

No abstract.

Peng, T.-H. Oceanic CO₂ uptake and future atmospheric CO₂ concentration. In Air-Water Mass Transfer: Selected Papers from the Second International Symposium on Gas Transfer at Water Surfaces. ASCE, New York, 618-636 (1991).

The global pattern of water column inventories of bomb-produced ¹⁴C suggests that an upwelling of bomb ¹⁴C-free water takes place in the Antarctic, northern Pacific, and equatorial regions, whereas a downwelling of bomb ¹⁴C-rich surface waters occurs in the temperate oceans and northern Atlantic. A global model of the closed ocean- atmosphere system is constructed on the basis of these dynamic flows for the purpose of estimating the oceanic uptake of excess CO₂. To produce a close match between the historical pattern of atmospheric CO₂ predicted by the model and that observed in the Siple ice core and the Mauna Loa record requires that a net release of 90 × 10¹⁵ g of carbon from the terrestrial ecosystem be posited for the period 1800-1990, in addition to fossil fuel CO₂ input. It is estimated that the ocean takes up, on average 2.4-2.6 × 10¹⁵ g of anthropogenic carbon each year. This net flux of CO₂ into the ocean is equivalent to 44% of the estimated total for anthropogenic CO₂ emissions. The model uses four scenarios of future CO₂ emissions from fossil fuel consumption and tropical deforestation to predict atmospheric CO₂ concentrations. Although the resulting patterns of predicted CO₂ levels are similar to those in the report given by the Intergovernmental Panel on Climate Change (IPCC), the uptake of CO₂ from fossil fuel in the model is more efficient than that in the general box-diffusion models used by IPCC; that is, all predictions from the model are lower than those given by IPCC.

Peng, T.-H., and W.S. Broecker. Dynamical limitations on the Antarctic iron fertilization strategy. Nature, 349(6306):227-229 (1991).

Martin et al. have proposed an ingenious means by which the rise in atmospheric CO₂ content generated by the burning of fossil fuels and deforestation might be partially compensated. The idea is that plant production in the nutrient-rich surface waters of the Antarctic could be stimulated by the addition of dissolved iron, thereby reducing the CO₂ partial pressure in these waters and allowing CO₂ to flow from the atmosphere into the Antarctic Ocean. We have used a box model calibrated with transient tracer data to examine the dynamical aspects of this proposal, and conclude that after 100 years of totally successful fertilization the CO₂ content of the atmosphere would be lowered by only 10 ± 5% below what it would have been in the absence of fertilization. So if after 100 years the CO₂ content of the atmosphere were 500 µatm without fertilization, it would be between 425 and 475 µatm with full fertilization. In other words, if our model calibration is correct, even if iron fertilization worked perfectly it would not significantly reduce the atmospheric CO₂ content.

Peng, T.-H., and W.S. Broecker. Factors limiting the reduction of atmospheric CO₂ by iron fertilization. Limnology and Oceanography, 36(8):1919-1927 (1991).

A limit on the reduction in atmospheric CO₂ partial pressure (pCO₂) in the next century resulting from purposeful Fe fertilization of the Antarctic Ocean is estimated with an advection-diffusion model calibrated with transient tracer distributions. To evaluate the possible increase in atmospheric CO₂ with and without fertilization, we adopt a "business-as-usual" scenario of anthropogenic CO₂ emission. Such increase is computed from the atmospheric pCO₂ in the ocean-atmosphere total C system as it responds to this emission scenario. Assuming completely successful Fe fertilization, we calculate an 8% atmospheric CO₂ reduction for a case with a 3 cm² s^-1 vertical diffusivity and 17.4 Sv upwelling flux, as derived from distribution of bomb-¹⁴C in the ocean. Hence, if atmospheric pCO₂ reaches 800 µatm in the next century, the maximum possible reduction is ~64 µatm. Doubling of upwelling flux to 34.8 Sv results in a reduction of 96 µatm. If we assume the surface area of the Antarctic Ocean is 16% of the total ocean area instead of 10% as used in the standard case, the reduction is ~71 µatm. These results are independent of the respiration function adopted. As we hold the surface water PO₄ content at a near-zero value, it makes no difference at what depth the organic material is oxidized (or whether it falls to the bottom and accumulates). Changes in the gas exchange rate over the Antarctic Ocean also do not have a significant effect on the magnitude of atmospheric CO₂ drawdown. Doubling the gas exchange rate in the Antarctic region after fertilization results in a reduction of 68 µatm. Doubling of vertical diffusivity to 6 cm² s^-1 in Antarctic deep water yields a reduction of 75 µatm. The key parameters are the rate of upwelling in the Antarctic and the fate of this upwelled water. The length of the productive season influences the extent of pCO₂ reduction. For 8 months of productive fertilization our model yields a reduction of 60 µatm, for 4 months a reduction of 50 µatm, and for 2 months a reduction of 40 µatm. The maximum O₂ consumption in our standard case is estimated to be 133 µmol kg^-1 at a depth of 600 m. However, O₂ consumption depends on the reoxidation function in the subsurface water. If the organic flux reoxidizes completely in the upper 2000 m, the maximum consumption of O₂ at 500 m could teach 500 µmol kg^-1. Hence, depending on the reoxidation function, an anoxic Antarctic thermocline could result from Fe fertilization. Both calculations regarding the seasonality of production and those regarding oxygen reduction are highly sensitive to parameters over which we have little control. They are included only to emphasize their potential importance.

Philbrick, V.A., P.C. Fiedler, S.B. Reilly, R.L. Pitman, L.T. Ballance, G.G. Thomas, and D.W. Behringer. Report of ecosystem studies conducted during the 1990 eastern tropical Pacific dolphin survey on the research vessel David Starr Jordan. NOAA Technical Memorandum, NMFS-SWFC-160, 117 pp. (1991).

No abstract.

Piotrowicz, S.R., H.F. Bezdek, G.R. Harvey, M. Springer-Young, and K.J. Hanson. On the ozone minimum over the equatorial Pacific Ocean. Journal of Geophysical Research, 96(D10):18,679-18,687 (1991).

Since 1977, several ship and aircraft expeditions to the equatorial Pacific have reported extremely low (10 ppbv) or undetectable levels of ozone within the marine boundary layer. Of necessity, field programs from mobile platforms are limited in both their temporal and spatial coverage. However, a 10-year record of observations at the geophysical monitoring for climatic change site in American Samoa suggests that low ozone mixing ratios are a common occurrence and may reflect a spatially variable but permanent region of low ozone in the equatorial Pacific. The spatial and temporal limits of this feature, as well as some aspects of the intensity of the minimum, appear to be maintained by the large-scale atmospheric circulations of the equatorial Pacific. Perturbations in the large-scale circulations, as well as episodic events, are reflected in observations of ozone in the equatorial Pacific. Variations in the large-scale zonal circulation patterns (i.e., Walker circulation) of the equatorial Pacific appear to have a major influence on the spatial distribution of ozone across the equatorial Pacific. The relative importance of variations in large-scale meridional circulation patterns on the distribution of ozone in the tropical Pacific is uncertain; however, they may be important at latitudes somewhat removed from the equator such as at American Samoa.

Post, W.M., V.H. Dale, D.L. DeAngelis, L.K. Mann, P.J. Mulholland, R.V. O'Neill, T.-H. Peng, and M.P. Farrell. Formulating energy policies related to fossil fuel use: Critical uncertainties in the global carbon cycle. Proceedings, 1990 Southeast Climate Symposium, Global Change: A Southern Perspective, October 1990, 77-95 (1991).

No abstract.

POWELL, M.D. Meteorological aspects of Hurricane Hugo. In Hurricane Hugo One year Later: Proceedings of a Symposium and Public Forum, Charleston, SC, September 13-15, 1990, B.L. Sill and P.R. Sparks (eds.). American Society of Civil Engineers, New York, 11-40 (1991).

No abstract.

Powell, M.D. Surface wind distribution of Hurricane Hugo in the Carolinas. Preprints, 19th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 6-10, 1991. American Meteorological Society, Boston, 441-444 (1991).

No abstract.

Powell, M.D., P.P. Dodge, and M.L. Black. The landfall of Hurricane Hugo in the Carolinas: Surface wind distribution. Weather and Forecasting, 6(3):379-399 (1991).

Hurricane Hugo struck Charleston, South Carolina, on 22 September 1989 as the most intense hurricane to affect the United States since Camille in 1969. The northeastern eyewall, which contained the maximum winds measured by reconnaissance aircraft shortly before landfall, moved inland over a relatively unpopulated area and there were few fatalities. However, no observations were available to document the surface wind distribution in this part of the storm as it continued inland. To improve specification of surface winds in Hugo, empirically adjusted aircraft winds were combined with coastal, offshore, and inland surface observations and were input to the Ooyama objective analysis algorithm. The wind analysis at landfall was then compared with subsequent analyses at 3 and 6 h after landfall. Reconstruction of the surface wind field after landfall suggests that the maximum (~13 min mean) surface wind at the coast was 50 m s^-1 in the Bulls Bay region, ~40 km northeast of Charleston. Surface roughness over land caused wind speeds to drop off rapidly just inland of the coast to only 50% of values measured by reconnaissance aircraft at the same location relative to the storm over water. Despite relatively rapid increases in the central sea-level pressure and decreases in the mean circulation as Hugo progressed inland, hurricane-force wind gusts extended Hugo's damage pattern well past Charlotte, North Carolina, ~330 km inland. Accurate determination of surface wind distribution in landfalling hurricanes is dependent upon the spatial density and quality of surface wind measurements and techniques to adjust reconnaissance flight-level winds to the surface. Improvements should allow forecasters to prepare more accurate warnings and advisories and allow more thorough documentation of poststorm effects. Empirical adjustments to reconnaissance aircraft measurements may replace surface data voids if the vertical profile of the horizontal wind is known. Expanded use of the airborne stepped-frequency microwave radiometer for remote sensing of ocean surface winds could fill data voids without relying upon empirical methods or models. A larger network of offshore, coastal, and inland surface platforms at standard (10 m) elevations with improved sampling strategies is envisioned for better resolution of hurricane wind fields. A rapid-response automatic station network, deployed at prearranged coastal locations by local universities with meteorology and/or wind engineering programs, could further supplement the fixed platform network and avoid the logistical problems posed by sending outside teams into threatened areas.

Pszenny, A.A.P. Particle size distributions of methanesulfonate in the Tropical Pacific marine boundary layer. Journal of Atmospheric Chemistry, 14(1-4):273-284 (1991).

Fourteen high-volume cascade impactor samples were collected during a January-February 1990 research cruise in the tropical Pacific from Panama to 180 . Aqueous extracts of the samples were analyzed for methanesulfonate (MSA), sulfate, and the seasalt tracer ion magnesium. The majority of MSA size distributions showed no pronounced maximum on submicrometer particles, as has been observed elsewhere. Analysis of the data indicated that MSA was distributed essentially uniformly with the effective surface area of particles >0.5 µm in radius, which were primarily seasalt. Relatively less MSA was found in smaller particles which were primarily sulfate. These results are consistent with those from theoretical and laboratory experimental studies reported in the literature which suggest that MSA produced from photochemical oxidation of dimethylsulfide condenses on pre-existing particles in strong preference to nucleating into new particles. This implies that MSA may not contribute appreciably to enhancing cloud condensation nucleus populations in the remote tropical marine atmosphere.

Rao, R.R., R.L. Molinari, and J.F. Festa. Surface meteorological and near surface oceanographic atlas of the tropical Indian Ocean. NOAA Technical Memorandum, ERL AOML-69 (PB91-234286), 65 pp. (1991).

Historical observations of surface marine meteorology (COADS: 1950-1979), near surface vertical thermal structure (MOODS: 1948-1981), and near surface ship drift (Cutler and Swallow, 1984: 1854-1974) for the tropical Indian Ocean are compiled to generate mean monthly climatologies of several observed and derived parameters on a 2° x 2° grid. The derived parameters include surface heat exchanges, surface wind stress and its curl, mixed layer depth (MLD), vertical thermal gradient just beneath the mixed layer, depth of 20°C isotherms, and zonal and meridional near surface flow patterns. The formulations used in the derivation of these quantities are also presented. The resultant climatological fields are machine contoured. The annual cycle of many of the fields are presented in terms of amplitude and phase of the annual and semi-annual harmonics.

Rona, P.A. Frontier of seafloor hydrothermal research. Proceedings, 11th Meeting of U.S.-Japan Cooperative Program in Natural Resources, Tokyo, Japan, September 26-27, 1991. Japan Science and Technology Agency, 325-345 (1991).

The back-arc basins in marginal seas behind volcanic island chains of the central and western Pacific Ocean are at the frontier of new discoveries of seafloor hydrothermal activity. Knowledge of the chemistry, physics, and biology of the hydrothermal sites in these basins is essential to achieve a global understanding of the role of seafloor hydrothermal processes in the ocean environment, climate change, mineralization, and biologic adaptation. Research approaches similar to those being utilized in investigations of hydrothermal systems at oceanic ridges are needed to develop complementary knowledge of hydrothermal systems in back-arc basins. These investigations include solution chemistry, ore-forming processes, magnetic signatures of hydrothermal activity, conductive and convective heat transfer, hydrothermal plume behavior, and vent biota.

Rona, P.A., D.R. Palmer, C. Jones, D.A. Chayes, M. Czarnecki, E.W. Carey, and J.C. Guerrero. Acoustic imaging of hydrothermal plumes, East Pacific Rise, 21°N, 109°W. Geophysical Research Letters, 18(12):2233-2236 (1991).

We report the first observations based on acoustic imaging of large-scale structure and time variability of buoyant plumes emanating from black smoker-type seafloor hot springs. Three-dimensional plume reconstructions were made from a digital data set of acoustic backscattering information recorded on a prototype submersible-mounted sonar system. The acoustic images of two adjacent black smokers depict volume and show zones of flow organization (meters to tens of meters) in the lower 40 m of the buoyant plumes. The two plumes coalesce, bend in the prevailing current, exhibit short-term (minutes) variation in cross section, and rapid (seconds) turbulent eddy variations at small scales (<1 m). The plume imaging system is being developed for determination of plume dynamics, flux determinations when combined with chemical and thermal measurements, and long-term monitoring of the activity of seafloor hydrothermal fields.

Rosenthal, S.L. A note on relationships between western Sahel rainfall and U.S. hurricane activity. NOAA Technical Memorandum, ERL AOML-68 (PB91-176511), 22 pp. (1991).

A recent research paper concluded that the probabilities of major hurricane strikes on the east coast of the United States, particularly the east coast of Florida, are greatly enhanced when rainfall over the western Sahel is abundant and that these probabilities are substantially smaller when drought conditions prevail over the western Sahel. This conclusion was based upon a 43-year sample of 1947-1989. In the work presented here, a search is made for simple, statistically significant (at the 5% or better level) relationships between western Sahel rainfall for 1947-1990 and eight types of hurricanes that are defined in the text. When hurricane frequencies for the 11 wettest and 11 driest western Sahel years are compared, statistically significant differences are found for all hurricane types studied, except for Florida landfalling hurricanes. Significant relationships are found for major hurricanes striking the east coast of the United States north of Florida, and for hurricanes of all intensities striking the east coast of the United States north of Florida. However, no significant relationships are found for hurricanes striking Florida. When the wetter 22 years are compared with the drier 22 years, a statistically significant relationship is found for the total of hurricanes of all intensities that strike the Florida Peninsula. For this type of hurricane, the largest frequency is found in the second quartile of western Sahel rainfall years and not in the wettest quartile. This makes the interpretation of the results difficult.

Roux, F., and F.D. Marks. Eyewall evolution in Hurricane Hugo deduced from successive airborne Doppler observations. Preprints, 19th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 6-10, 1991. American Meteorological Society, Boston, 558-563 (1991).

No abstract.

Roux, F., F.D. Marks, and J.F. Gamache. Three-dimensional circulation in a hurricane from airborne Doppler radar data: Extended velocity track display. Preprints, 25th International Conference on Radar Meteorology, Paris, France, June 24-28, 1991. American Meteorological Society, Boston, 466-469 (1991).

No abstract.

Roy, R.N., J.-Z. Zhang, and F.J. Millero. The ionization of sulfurous acid in Na-Mg-Cl solutions at 25°C. Journal of Solution Chemistry, 20(4):361-373 (1991).

The stoichiometric pK₁^* and pK₂^* for the ionization of sulfurous acid has been determined from EMF measurements in NaCl solutions with varying concentrations of added MgCl₂ (m = 0.1, 0.2, and 0.3) from I = 0.5 to 6.0 molal at 25°C. These experimental results have been treated using both the ion pairing and Pitzer's specific ion-interaction models. The Pitzer parameters for the interaction of Mg²⁺ with SO₂ and HSO₃^- yielded lambda = 0.085 ± 0.004, beta⁽⁰⁾ = 0.35 ± 0.02, beta⁽¹⁾ = 1.22 ± 0.04, and C^phi = -0.072 ± 0.007. The Pitzer parameters beta⁽⁰⁾ = -2.8 ± 0.4, beta⁽¹⁾ = 12.9 ± 2.9, and beta⁽²⁾ = -201 ± 57 have been determined for the interactions of Mg²⁺ with SO₃^2-. The calculated values of pK₁^* and pK₂^* using Pitzer's equations reproduce the measured values to within ± 0.04 pK units. The ion pairing model with log K_MgSO3 = 2.36 ± 0.02 and log gamma_MgSO3 = 0.1021, reproduces the experimental values of pK₂^* to ± 0.01. These results demonstrate that treating the data by considering the formation of MgSO₃ yields a better fit of the experimental measurements with fewer adjustable parameters. With these derived coefficients obtained from the Pitzer equations and the ion pairing model, it is possible to make reliable estimates of the activity coefficients of HSO₃^- and SO₃^2- in seawater, brines, and marine aerosols containing Mg²⁺ ions.

Roy, R.N., J.-Z. Zhang, M.A. Sibblies, and F.J. Millero. The pK₂^* for the dissociation of H₂SO₃ in NaCl solutions with added Ni²⁺, Co²⁺, Mn²⁺, and Cd²⁺ at 25°C. Journal of Solution Chemistry, 20(5):467-478 (1991).

The pK₂^* for the dissociation of sulfurous acid from I = 0.5 to 6.0 molal at 25°C has been determined from EMF measurements in NaCl solutions with added concentrations of NiCl₂, CoCl₂, MnCl₂, and CdCl₂ (m = 0.1). These experimental results have been treated using both the ion pairing and Pitzer's specific ion-interaction models. The Pitzer parameters for the interactions of M²⁺ with SO₃^2- yielded

beta⁽⁰⁾_NiSO3 = -5.5, beta⁽¹⁾_NiSO3 = 5.8, and beta⁽²⁾_NiSO3 = -138

beta⁽⁰⁾_CoSO3 = -12.3, beta⁽¹⁾_CoSO3 = 31.6, and beta⁽²⁾_CoSO3 = -562

beta⁽⁰⁾_MnSO3 = -8.9, beta⁽¹⁾_MnSO3 = 18.7, and beta⁽²⁾_MnSO3 = -353

beta⁽⁰⁾_CdSO3 = -7.2, beta⁽¹⁾_CdSO3 = 13.8, and beta⁽²⁾_CdSO3 = -489

The calculated values of pK₂^* using Pitzer's equations reproduce the measured values to within ± 0.01 pK units. The ion pairing model yielded

log K_NiSO3 = 2.88 and log gamma_NiSO3 = 0.11I

log K_CoSO3 = 3.08 and log gamma_CoSO3 = 0.05I

log K_MnSO3 = 3.00 and log gamma_MnSO3 = 0.04I

log K_CdSO3 = 3.29 and log gamma_CdSO3 = 0.17I

for the formation of the complex MSO₃. The stability constants for the formation of MSO₃ complexes were found to correlate with the literature values for the formation of MSO₄ complexes.

Shapiro, L.J. The effect of vertical wind shear on hurricane motion in a three-layer model. Preprints, 19th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 6-10, 1991. American Meteorological Society, Boston, 356-357 (1991).

No abstract.

Shay, L.K., P.B. Black, J.D. Hawkins, R.L. Elsberry, and A.J. Mariano. Sea surface temperature response to Hurricane Gilbert. Preprints, 19th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 6-10, 1991. American Meteorological Society, Boston, 574-578 (1991).

No abstract.

Tappert, F.D., G.J. Goni, and M.G. Brown. Weak chaos in an area-preserving mapping for sound ray propagation. Physics Letters A, 153(4-5):181-185 (1991).

No abstract.

Thacker, W.C. Automatic differentiation from an oceanographer's perspective. In Automatic Differentiation of Algorithms: Theory, Implementation, and Application, A. Griewank and G.F. Corliss (eds.). Society of Industrial and Applied Mathematics (SIAM), Philadelphia, 191-201 (1991).

An automatic differentiator is a tool that, when given code for evaluating a function, generates additional code for evaluating its derivatives. Within an oceanographic context, the function-defining code often involves the numerical solution of a system of partial-differential equations, and the corresponding derivative-evaluating code involves the solution of the adjoint system. Because the task of preparing the adjoint code is tedious, time-consuming, and error-prone, an automatic differentiator that could serve as an automatic adjoint generator would be most valuable. To be practical, its design should reflect the fact that, for oceanographic applications, efficient use of storage is crucial. In handwritten adjoint codes, data compression is realized by saving expressions rather than values. This expression-saving approach can be automated. The design of the automatic differentiator would resemble that of a compiler, and compiler-building tools could be used to construct it.

Wanninkhof, R.H., and L.F. Bliven. Relationship between gas exchange, wind speed, and radar backscatter in a large wind-wave tank. Journal of Geophysical Research, 96(C2):2785-2796 (1991).

Gas transfer velocities across the air-water interface are correlated with wind speed, friction velocity, and radar backscatter from the surface in a large wind-wave tank in Delft, The Netherlands. The rates of sulfur hexafluoride and nitrous oxide exchange were measured at wind speeds ranging from 3.5 m/s to 20 m/s, and with mechanically generated waves in the 100 m long, 8 m wide, and 0.7 m deep tank. Gas transfer velocities were related to wind speed with a power law dependence. Gas transfer showed a linear dependence with friction velocity. An exponential relationship between gas transfer and average radar backscatter cross section fits the wind tunnel data well for microwave units operating at 13.5 and 35 GHz in VV and HH polarization. The relative rates of gas exchange of the two gases confirm an inverse square root dependence on the Schmidt number at intermediate wind speeds. A slight enhancement of sulfur hexafluoride exchange compared to nitrous oxide exchange was evident when breaking waves were present.

Wanninkhof, R.H., J.R. Ledwell, and A.J. Watson. Analysis of sulfur hexafluoride in seawater. Journal of Geophysical Research, 96(C5):8733-8740 (1991).

Analysis procedures and instrumentation to measure low levels of sulfur hexafluoride in seawater are described. The minimum detectable level for a 500 mL sample is about 3 x10^-17 mol/L. Concentrations from 1.5 to 300 x 10^-15 mol/L can be measured with approximately 2% precision. The procedure includes a concentration step employing a trap of Porapak-Q^c in a dry ice/2-propanol bath. The system has been used for tracer experiments in Santa Monica Basin and Santa Cruz Basin, and will be improved for future tracer release experiments in the deep ocean.

Wilburn, A.M. Shipboard acoustic Doppler current profiler data collected during the Subtropical Atlantic Climate Studies (STACS) Project (1983-1986). NOAA Data Report, ERL AOML-20 (PB91-178400), 177 pp. (1991).

Ocean current profiles measured during the Subtropical Atlantic Climate Studies (STACS) project of NOAA between December 1983 and September 1987 are described. The STACS project is directed at determining the role of the ocean circulation in global atmospheric climate, obtaining data for numerical model verification, and establishing monitoring strategies for climatically important circulation features. The data were collected aboard NOAA research ships in the Florida Current, Caribbean Sea, the Antillean Archipelago, and down to 4°N latitude using an acoustic Doppler current profiler.

Willis, P.T., and J. Hallett. Microphysical measurements from an aircraft ascending with a growing isolated maritime cumulus tower. Journal of the Atmospheric Sciences, 48(2):283-300 (1991).

The development of precipitation in the top of an isolated marine cumulus is traced by four rapid penetrations with an instrumented aircraft between 400 and 1000 m below the visible top of the growing tower. The hydrometeor distribution evolves from the first appearance of a few large supercooled drops [0.45 l^-1, D > 0.5 m] to well-developed precipitation (largely ice) in 500 s. This development results from accretion and coalescent growth in the cloud top volume, not from advection by the updraft of large drops from below. Large supercooled drops precede the appearance of ice at -9°C near the cloud top. The cloud and precipitation water budgets are computed and compared with observed values, which indicate that, once precipitation is well-developed, the convective tower cannot maintain itself as a steady-state entity. The budget computations demonstrate a sensitivity of cloud evolution to the ice particle density.

Willis, P.T., and A.J. Heymsfield. Trajectories of hydrometeors in Hurricane Emily. Preprints, 19th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 6-10, 1991. American Meteorological Society, Boston, 192-197 (1991).

No abstract.

Willis, P.T., F.D. Marks, and J. Hallett. Tracing the interactions of precipitation evolution and cloud dynamics using airborne Doppler radar and in-situ data. Preprints, 25th International Conference on Radar Meteorology, Paris, France, June 24-28, 1991. American Meteorological Society, Boston, 916-919 (1991).

No abstract.

Willoughby, H.E. Reply. Journal of the Atmospheric Sciences, 48(9):1209-1212 (1991).

No abstract.

Willoughby, H.E. Semispectral models of moving hurricane-like vortices. Preprints, 19th Conference on Hurricanes and Tropical Meteorology, Miami, FL, May 6-10, 1991. American Meteorological Society, Boston, 383-384 (1991).

No abstract.

Winter, A., C. Goenaga, and G.A. Maul. Carbon and oxygen isotope time series from an 18-year Caribbean reef coral. Journal of Geophysical Research, 96(C9):16,673-16,678 (1991).

Colonies of Montastrea annularis live near La Parguera, Puerto Rico, which may be 700 years old. Time series from 1964 to 1982 of ¹³C and ¹⁸O from a continuous core of these corals are compared to an adjacent environmental record. At the intra-annual level, ¹⁸O correlates well with water temperature. Changes in the amplitude of the ¹⁸O signal between 1967-1976 are attributed to sampling frequency but may be also due to environmental changes such as salinity. Average annual ¹⁸O, ¹³C and sea surface temperature show similar trends for the period from 1964-1982 but especially from 1969 onwards. Changes in average annual values during this time interval are most likely due to water mass changes brought about by interannual variability of the North Atlantic circulation. Since water temperatures at La Parguera are representative of changes occurring in the wider Caribbean, the isotope record from La Parguera corals could be used as a proxy for large scale environmental changes beyond the historical record through the Little Ice Age.

Zhang, J.-Z., and F.J. Millero. The rate of sulfite oxidation in seawater. Geochimica et Cosmochimica Acta, 55:677-685 (1991).

The rate of oxidation of sulfide, S(IV), in seawater was measured as a function of pH (4.0-8.5), temperature (15-45°C), and salinity (0-35). The observed rate constant, k, in seawater at a pH = 8.2 was found to be second order with respect to S(IV) and half order with respect to oxygen:

-d [S(IV)]/dt = k[S(IV)]² [O₂]^0.5.

The resulting values of k (M^-1.5 min^-1) have been fitted to a function of ionic strength, I, and temperature, T(K):

log k = 19.54 - 5069.47/T + 14.74I^0.5 - 2.93I - 2877.0I^0.5/T,

and the standard error is 0.05 in log k. The energy of activation was found to be a function of salinity and has a value of 140 ± 6 kJ mol^-1 at S = 35. The rates measured in 0.57 M NaCl were found to be higher than the rates in seawater. Measurements made in the major sea salts indicate that Ca²⁺, Mg²⁺, and SO₄^2- added to NaCl cause the decrease. Measurements made in artifical seawater (Na⁺, Mg²⁺, Ca²⁺, Cl^-, and SO₄^2-) were found to be in good agreement with the measurements in real seawater. The rate increased from pH 4 to a maximum at pH 6.5 and decreased at higher pH. The effect of Ph on the rates was attributed to the rate-determining step involving the combination of HSO₃^- and SO₃^2-. This yields:

k = k” alpha HSO₃ - alpha SO₃^2-

where alpha_i is the molar fraction of species i. Values of k” equal to 6.66 ± 0.06 and 6.17 ± 0.17 were found for NaCl and seawater, respectively. The larger range of k” in seawater is due to it being a function of pH. The addition of Mn²⁺ was found to increase the rate apparently due to the formation of MnSO₃. Additions of Fe³⁺ and Fe²⁺ have a catalytic effect only before they hydrolyze to colloidal iron.

**1990**

Baik, J.-J., M. DeMaria, and S. Ramen. Tropical cyclone simulations with the Betts convective adjustment scheme. Part I: Model description and control simulation. Monthly Weather Review, 118(3):513-528 (1990).

A new convective parameterization scheme proposed by Betts is tested in a tropical cyclone model. The convective adjustment scheme adjusts the local temperature and moisture structures towards the observed quasi-equilibrium thermodynamic state and includes nonprecipitating shallow convection, as well as deep convection. The numerical model used for this study is an axisymmetric, primitive equation, hydrostatic, finite difference model with 15 vertical levels and a horizontal resolution of 20 km. The spectral radiation boundary condition, which uses a different gravity wave speed for each vertical mode, is implemented in the model. It is shown that the convective scheme is capable of simulating the developing, rapidly intensifying, and mature stages of a tropical cyclone from a weak vortex. At the mature stage, the minimum surface pressure and maximum low level tangential wind speed are around 923 mb and 58 m s^-1. During the early developing stage, the latent heat release is from the convective parameterization, but at the mature stage the latent heat release is mainly due to the grid-scale phase change. For comparison, an experiment is conducted with the parameterized convection excluded, leaving only the grid-scale condensation and evaporation. The results show that the development of a tropical cyclone can be modeled with crude grid-scale condensation and evaporation processes for the 20 km horizontal resolution, similar to other studies. However, the storm with the explicit convective latent heat release is considerably less intense than that with the parameterized convective latent heat release.

Baik, J.-J., M. DeMaria, and S. Ramen. Tropical cyclone simulations with the Betts convective adjustment scheme. Part II: Sensitivity experiments. Monthly Weather Review, 118(3):529-541 (1990).

Extensive sensitivity experiments with an axisymmetric tropical cyclone model that includes the Bets convective parameterization scheme are carded out. The sensitivity of the model storm evolution to the convective adjustment parameters is studied. These results show that the model storm leads to earlier development as the adjustment time scale becomes small and the stability weight on the moist adiabat in the lower atmosphere is increased. The model storm evolution is very sensitive to variations in the saturation pressure departure at the lowermost model integer level and the storm at mature stage has a lower central pressure as the magnitude of the saturation pressure departure is increased. The adjustment parameters affect the grid-scale precipitation as well as the convective precipitation and the precipitation is especially sensitive to changes in the saturation pressure departure. Sensitivity of the model to variations in the sea surface temperature, latitude, initial vortex amplitude, initial moisture distribution, and radiation is also investigated. The results of the numerical simulations are similar to previous studies. Sensitivity studies with various horizontal resolutions show that the subgrid-scale heating becomes a larger fraction of the total heating as the horizontal grid size is increased.

Baringer, M.O., and J.F. Price. A simple model of the descending Mediterranean outflow plume. Proceedings, NATO Advanced Research Institute on the Physical Oceanography of Sea Straits, L.J. Pratt (ed.), Kluwer Academic Publishers, 298-308 (1990).

No abstract.

Bitterman, D.S., P.P. Niiler, Y. Aoustin, and A. du Chaffaut. Drift buoy intercomparison results. NOAA Data Report, ERL AOML-17 (PB90-268301), 59 pp. (1990).

Intercomparison tests of drift buoys to be used in the Tropical Ocean-Global Atmosphere (TOGA) Pan Pacific Surface Current Study were conducted from the NOAA Ship Oceanographer during its cruise from American Samoa to Hawaii in support of the Equatorial Pacific Ocean Climate Studies (EPOCS) program. The ship departed American Samoa on May 10, 1988 and arrived in Honolulu, Hawaii on June 4, 1988. While underway, the primary tasks included CTD sampling with chemical and nutrient analysis, deploying and recycling ATLAS, current meter and upward-looking acoustic Doppler mooring arrays, population surveys of aquatic and bird species, and the buoy intercomparison tests.

Black, R.A. Radar reflectivity-ice water content relationships for use above the melting level in hurricanes. Journal of Applied Meteorology, 29(9):955-961 (1990).

Regression of equations linking radar reflectivity (Z_e) and ice water content (IWC) were calculated from airborne radar and particle image data that were collected above the melting level in two hurricanes. The Z_e-IWC equation from the stratiform areas of Hurricane Norbert (1984) is similar to the composite equation for thunderstorm anvils derived by Heymsfield and Palmer. The Z_e-IWC equation from the convective regions of Hurricane Irene (1981) has essentially the same exponent, but a significantly greater coefficient than that from Norbert. The higher density of the graupel and rounded ice in the Hurricane Irene data accounts for the difference in the coefficients. The hurricane Z_e-IWC relations have smaller exponents than most of those from midlatitude clouds, which indicates that small ice particles may be more prevalent in these two hurricanes than in midlatitude clouds.

Black, R.A., and J. Hallett. Electric field and microphysical measurements in vigorous hurricane eyewalls. Preprints, Conference on Cloud Physics, San Francisco, CA, July 23-27, 1990. American Meteorological Society, Boston, 662-665 (1990).

No abstract.

Boatman, J.F., W.C. Keene, M. Luria, J.D. Ray, C.A. Bardwell, K. Gorzelska, M. Fennell, D.R. Hastie, A.A.P. Pszenny, and D. Whelpdale. An intercomparison of the chemical and meteorological data generated from aircraft and shipboard sampling during GCE/CASE/WATOX. NOAA Technical Memorandum, ERL ARL-186, 26 pp. (1990).

We compared 16 selected chemical and meteorological parameters from the NOAA Ship Mt. Mitchell and the NOAA King Air research aircraft during the GCE/CASE/WATOX experiment. The aircraft made eight research flights during July 1988 in coordination with the ship. The first four were off the U.S. east coast near Newport News, Virginia and the last four were near the island of Bermuda. We used only the low altitude portions of the aircraft flights in our ship to aircraft intercomparisons. Generally, the aircraft and shipboard measurements were within expected accuracy limits. Selected exceptions for individual species and days are noted and discussed in the text.

Broecker, W.S., T.-H. Peng, J. Jouzel, and G. Russell. The magnitude of global fresh-water transports of importance to ocean circulation. Climate Dynamics, 4:73-79 (1990).

Water-vapor transport from low to high latitudes in a given ocean and from one ocean to another must be compensated by a net flow of salt through the sea. A comparison is presented which shows that water-vapor fluxes derived from meteorological information, from an atmospheric general circulation model and from a radiocarbon-calibrated ocean box model are in first-order agreement.

Broecker, W.S., T.-H. Peng, S. Trumbore, G. Bonani, and W. Wolfli. The distribution of radiocarbon in the glacial ocean. Global Biogeochemical Cycles, 4:103-117 (1990).

Accelerator mass spectrometric radiocarbon measurements on benthic foraminifera shells, picked from samples on which concordant ages were obtained on the shells of two species of planktonic foraminifera, reveal that the age of deep water in the equatorial Atlantic during glacial time was 675 ± 80 years (compared to today's age of 350 years) and that the age of deep water in the South China Sea was 1670 ± 105 years (compared to today's value of 1600 years). These results demonstrate that the 1.3 to 1.5 times higher radiocarbon content of carbon in glacial surface waters of the Caribbean Sea reconstructed by Bard et al. (1990) was primarily the result of a higher global inventory of radiocarbon rather than a decrease in rate of mixing between surface and deep waters of the ocean. The results are also consistent with the conclusion by Boyle and Keigwin (1987) that the flow of North Atlantic Deep Water was considerably weakened during glacial time, allowing deep waters of Antarctic origin to push much further north into the Atlantic than they do today.

Burpee, R.W. Radar characteristics of hurricanes. In Federal Meteorological Handbook No. 11, Doppler Weather Radar Observations, Part B: Radar Meteorology and Theory. Federal Coordinator for Meteorological Services and Supporting Research, Washington, D.C., 1-14 (1990).

No abstract.

Carey, A.G., D.L. Stein, and P.A. Rona. Benthos of the Gorda Ridge axial valley (northeast Pacific Ocean): Taxonomic composition trends in distribution. Progress in Oceanography, 24(1-4):47-57 (1990).

Distribution and relative abundance of invertebrate mega-epifauna and benthic fishes were studied in the Gorda Ridge central rift valley off southern Oregon and northern California, USA. Faunal distribution and relative abundance were correlated with location, geological setting, substrate type, and depth. Bottom photographs and videotapes were from 1985-1986 cruises by the U.S. Geological Survey and the U.S. National Oceanic and Atmospheric Administration. Voucher specimens were collected by rock dredge, fish trap, and the Deep Submergence Vehicle (DSV) Sea Cliff. Location rather than substrate appears to have more effect on the overall taxonomic composition of the mega-epifauna in the northern and southern parts of the rift valley. Within each location, substrate type, i.e., soft sediments and rock outcrops, and percentage cover of these substrates appear to influence the existing faunal composition. Characteristic fauna are associated with each substrate type, e.g., crinoids, gorgonians and sponges (Demospongiae) on rocky surfaces. In the southern sediment-filled Escanaba Trough, deposit-feeding organisms, particularly ophiuroids, asteroids and holothuroids, are interspersed with stalked suspension feeders, such as hexactinellid sponges and pennatulids. Epifaunal community structure in the northern and southern sectors differs, even on similar substrate combinations. Except for the ubiquitous macrourids, fish species distributions may be correlated with substrate type. Abundant particulate material in the bottom water layer probably accounts for large concentrations of suspension and detritus feeding epibenthos.

Carey, A.G., G.L. Taghon, D.L. Stein, and P.A. Rona. Distributional ecology of selected benthic megaepifauna and fishes in the Gorda Ridge axial valley. In Gorda Ridge: A Seafloor Spreading Center in the United States' Exclusive Economic Zone, G.R. McMurray (ed.). Springer-Verlag, New York, 225-240 (1990).

Using bottom photographs and videotapes taken by various institutions in 1984 to 1986, we describe the taxonomic composition and patterns of distribution on two geographic scales and the relative abundance of the benthic epifauna and fishes in Gorda Ridge axial valley. Gorda Ridge runs approximately northeast-southwest 200 to 300 km off northern California and southern Oregon and lies within the U.S. Exclusive Economic Zone. Suspension feeding invertebrate taxa occur in all rocky and sedimentary environments. Crinoids appear dominant at the northernmost stations, and ascidians are dominant in the central Gorda Ridge region. In the sedimented Escanaba Trough, hexacitinellid sponges and gorgonian soft corals are present. Suspension feeding epifauna tend to occur nonrandomly with even distributions predominant. Assemblages of invertebrates and fishes associated with rock and sediment differ in composition and abundance. Deposit feeding organisms become relatively more abundant and are interspersed with stalked suspension feeders at the southern stations of the sediment-filled southern Escanaba Trough. Many species associated with sediments are similar to those found on the surrounding abyssal plains. Biomass is unevenly distributed. The axial valley fauna is abundant and diverse, undoubtedly supported by organic materials of continental origin, including runoff from the Columbia River. In addition, scattered hydrothermal venting provides energy sources for adjacent chemosynthesis-based food webs. The enclosing valley walls and rough topography appear to constrain currents and cause turbulence that maintains the high concentrations of suspended particles observed near the valley floor.

Chelton, D.B., A.M. Mestas-Nunez, and M.H. Freilich. Global wind stress and Sverdrup circulation from the SEASAT scatterometer. Journal of Physical Oceanography, 20(8):1175-1205 (1990).

Three months of vector wind observations from the SEASAT-A satellite scatterometer (SASS) are used to construct gridded fields of monthly average wind stress and wind stress curl over the global ocean. These fields are examined to identify features either poorly resolved or not present in wind stress fields constructed from conventional data. Particular attention is focused on the spatial structures in the high southern latitudes and the tropical regions. The SASS wind stress fields are compared globally with the Hellerman and Rosenstein climatological monthly average surface wind stress fields and with monthly averages of wind stress computed from contemporaneous 1000 mb wind analyses produced by the National Meteorological Center. The potential for satellite scatterometry improving the present knowledge of the global wind stress field and making important contributions to ocean modeling is demonstrated by comparison of global maps of the Sverdrup circlation computed from three-month average SASS and Hellerman and Rosenstein climatological wind stress curl fields. Except for the region south of about 35°S, the two estimates of Sverdrup circulation are generally very similar. The transports of the western boundary currents calculated from the climatological wind stress fields are consistently higher because the drag coefficient used by Hellerman and Rosenstein is too large by approximately 19%. In the Antarctic Circumpolar Current region, the difference between the two estimates of zonal transport is very large, even disagreeing in direction in the region south of Australia and New Zealand. Historical hydrographic data suggest a tendency, albeit less extensive, for the westward Sverdrup transport indicated by the SASS data, suggesting the possibility of deficiencies in the climatological wind stress fields.

Chew, F., and M.H. Bushnell. The half-inertial flow in the eastern equatorial Pacific: A case study. Journal of Physical Oceanography, 20(7):1124-1136 (1990).

We address the problem of the oscillatory periods of two observed phenomena in the instability zone in the eastern equatorial Pacific. The first case concerns two high-speed anticyclonic flow with periods of approximately 12 and 15 mean solar days. The second concerns the long waves with an average period of about 25 days. The problem is that, in terms of their respective mean latitudes, these periods are about twice as large as those of the inertial period of one-half pendulum day. As a solution we offer the hypothesis of the half-inertial flow with its period of one pendulum day. The inertial flow is governed by KV = -f, where K is the path curvature, V the speed of the flow, and f the Coriolis parameter. In contrast, the half-inertial flow is governed by KV = -f/2 with a speed that is the maximum for a given curvature and latitude and approaches twice that of the geostrophic speed. In terms of the half-inertial flow, the average lone-wave period of 25 days would correspond to a plausible mean latitude of 2.3°N. Efficient at extracting horizontal shear energy, the half inertial flow could also play an important role in the near-surface heat balance.

Clague, D.A., and P.A. Rona. Geology of the GR14 site on the northern Gorda Ridge. In Gorda Ridge: A Seafloor Spreading Center in the United States' Exclusive Economic Zone, G.R. McMurray (ed.). Springer-Verlag, New York, 31-50 (1990).

The northern Gorda Ridge is spreading at an intermediate rate but exhibits a deep, well-defined rift valley and petrologic diversity more like the slow-spreading Mid-Atlantic Ridge than other oceanic ridges with intermediate rates of spreading. A detailed investigation of a 10 km by 10 km area of the floor and eastern wall of the rift valley was conducted in order to define the geologic setting of active high-temperature hydrothermal vents regionally located using water column studies. High temperature vents are apparently located on the east wall of the rift valley at the southern end of a linear ridge at a location where ridge-parallel and anomalous ridge-oblique tectonic trends intersect. Additional hydrothermal deposits were discovered along the axis of the valley floor near the shoal point of the axial valley of the northern Gorda Ridge, adjacent to an area of sheet flows. These deposits are of the two types: a massive material, probably nontronite, and white coatings on talus that consist of mixed layer clay and boehmite. These axial deposits do not appear to be actively forming. This study suggests that past and present hydrothermal activity occurs near the shallowest and volcanically most productive segment of the ridge, and the locations of the vents are controlled by the intersection of tectonic trends.

DeMaria, M. Normal mode initialization in a tropical cyclone model. Monthly Weather Review, 118(10):2199-2214 (1990).

The effect of nonlinear normal mode initialization (NMI) on tropical cyclone simulations is investigated using a three-layer axisymmetric model. It is shown that the balance condition proposed by Machenhauer, which neglects the time tendencies of the gravity-mode amplitudes, is valid in a tropical cyclone simulation. The boundary layer friction, adiabatic nonlinear and diabatic heating terms are important in the balance. A highly truncated version of the model with linearized physical parameterizations is used to analyze the convergence properties of several iterative schemes developed to solve the initialization equations. When diabatic heating is neglected, the schemes will always converge if the linear friction coefficient a is smaller than the Coriolis parameter f. For small horizontal-scale modes, the iterative schemes will also converge for values of a much larger than f. When diabatic beating is included, the rate of convergence of the small horizontal-scale modes becomes extremely slow. The schemes are also tested in the nonlinear version of the model by first running a 7-day tropical cyclone simulation. The initialization schemes are applied at day 5 after the model has produced an intense tropical cyclone. Results show that the tropical cyclone rapidly weakens relative to the uninitialized run during the 6-12 h after the NMI is applied. This weakening occurs because the small horizontal-scale modes do not converge, making the secondary radial circulation much too weak. A scheme is proposed where the NMI is followed by a short integration with the geostrophic modes held fixed. This procedure compensates for the lack of convergence of the small horizontal-scale gravity modes.

DeMaria, M., and R.W. Jones. The use of aircraft observations in a hurricane track forecast model. Preprints, International Symposium on Assimilation of Observations in Meteorology and Oceanography, Clermont-Ferrand, France, July 9-13, 1990. American Meteorological Society, Boston, 191-195 (1990).

No abstract.

DeMaria, M., M.B. Lawrence, and J.T.Kroll. An error of Atlantic tropical cyclone track guidance models. Weather and Forecasting, 5(1):47-61 (1990).

Mean track forecast errors over the 6-yr period 1983-88 are compared for four tropical cyclone-track forecast models in use at the National Hurricane Center (NHC). The model types represented are statistical, statistical-dynamical, barctropic-dynamical, and baroclinic-dynamical. The statistical-dynamical model (NHC83) had the smallest mean errors at all forecast periods between 12 and 72 h while the baroclinic-dynamical model (MFM) had the largest errors at 12 and 24 h. NHC83 was the only model which had statistically significant forecast skill relative to the CLIPER model. When the forecasts were stratified by latitude, the MFM had significant skill at 36 and 48 h for the northern storms. Further analysis of the forecast errors shows that most of the models have a bias towards the southwest. The MFM has a very large westward bias for low-latitude storms which results from a fast-speed bias in that region. NHC83 has relatively small speed and directional baises, while CLIPER and SANBAR have slow biases. The MFM has been replaced (beginning in 1988) by a new baroclinic-dynamical model, the quasi-Lagrangian model (QLM). A comparison of the MFM and QLM for the 1988 season shows that the QLM has error characteristics similar to the MFM. A barotropic-dynamical model is used to give some insight into the behavior of dynamical track prediction models. Results show that initial-position errors have a negligible effect on the average track forecast errors except at 12 h. Errors in the estimate of the initial storm motion affect the forecast errors out to 72 h. Several spatial filters are applied to the initial analyses which shows that the model storm track is the most sensitive to very large scales (3000-6000 km wavelengths).

Dodge, P.P., J.S. Griffin, F.D. Marks, and R.W. Burpee. Interactive analysis of NOAA P-3 aircraft data in support of operational hurricane forecasting. Preprints, Sixth International Conference on Interactive Information and Processing Systems for Meteorology, Oceanography, and Hydrology, Anaheim, CA, February 4-9, 1990. American Meteorological Society, Boston, 245-247 (1990).

No abstract.

Franklin, J.L. Dropwindsonde observations of the environmental flow of Hurricane Josephine (1984): Relationships to vortex motion. Monthly Weather Review, 118(12):2732-2744 (1990).

Omega dropwindsonde (ODW) observations from three synoptic-flow experiments in environment of Hurricane Josephine have been analyzed in a research mode using an objective analysis procedure. The nominal times of the analyses are 0000 UTC 10, 11, and 12 October 1984. The filtered, three-dimensional analyses have been used as a basis for several diagnostic and prognostic calculations relating to the motion of the hurricane. Examination of Josephine's environment revealed a strong variability of the flow with distance from the storm center and with pressure. Josephine moved at right angles to the azimuthally averaged wind at 500 mb; the vortex motion was more consistent with the flow near 700 mb. Forecasts made with a barotropic forecast model showed a high sensitivity of the forecast track to the vertical layer used in the initial analysis. These results demonstrate the potential value of vertical sounding information from the ODWs, and show that single-level midtropospheric information is not always representative of a hurricane's environment flow. On each of the three days, the motion of Josephine deviated significantly from its environmental "steering," as measured by an azimuthal average of the 300-850 mb mean flow over the 5 -7 radial band. This deviation from steering (the so-called "propagation" vector) was oriented with components parallel and to the left of the gradient of absolute vorticity in the asymmetric wind field. The magnitude of the propagation was proportional to the strength of the absolute vorticity gradient. These results are consistent with many barotropic modeling studies.

Franklin, J.L., C.S. Velden, J. Kaplan, and C.M. Hayden. Some comparisons of VAS and dropwindsonde data over the subtropical Atlantic. Monthly Weather Review, 118(9):1869-1887 (1990).

Omega dropwindsonde and other in-situ (INS) data collected during the NOAA/Hurricane Research Division's (HRD) field program are used as a ground truth data set for the evaluation of VISR Atmospheric Sounder (VAS) soundings over the subtropical Atlantic. The experiments were coordinated with the Cooperative Institute for Meteorological Satellite Services at the University of Wisconsin. The focus of this study is to determine whether soundings derived from VAS radiances are an improvement over the first-guess data used as a starting point in the sounding retrieval process. First-guess inputs for this study are provided by NMC's Regional Analysis and Forecast System (RAFS) nested-grid model (NGM). In a case study, an objective algorithm is used to analyze the INS, VAS, and first-guess data at and below 500 mb from an HRD experiment on 1-2 September 1988. The case study is supplemented by a statistical investigation of data composited from other HRD experiments. In particular, we examine VAS estimates of horizontal temperature and moisture gradients to see if they represent improvements over the first guess. The temperature and moisture descriptions in the vicinity of a 500 mb cold low were improved by the VAS in the case study; however, VAS temperature gradients were found to be generally less accurate than those of the first guess. Temperature gradients from the VAS were also consistently stronger than INS or first-guess gradients. The composite study found that large-scale VAS moisture gradients were better than those of the first guess. Other results indicate a preferred mode for VAS modifications to the guess; the primary impact of the VAS radiances on the first guess was to improve the description of the phasing of horizontal features. The VAS representation of the amplitude of features, however, was not consistently an improvement. This suggests that in tropical applications, VAS data may be most suitable for subjective forecasting uses; if VAS data are to be used in numerical weather prediction, strongest weight should be given to the representation of the location of weather features (troughs, ridges, etc.), and relatively weak weight should be given to the representation of the strength of these features.

Frazel, D.W., and G.A. Berberian. Distributions of chlorophyll and primary productivity in relation to water column structure in the eastern North Atlantic Ocean. Global Biogeochemical Cycles,4(3):241-251 (1990).

Latitudinal variations in the megascale (10³ km) distribution of biological properties are described in relation to water column structure between 60°N and 7°N in the eastern North Atlantic Ocean. Stations were occupied along a meridional transect of stations at 20°W in August-September 1988, during the third leg of the National Oceanic and Atmospheric Administration Global Change Expedition. An additional transect to the south (38°N to 7°N) was occupied to extend the total range of latitudinal observations. Chlorophyll-a concentrations were highest in the northern latitudes (<2.51 mg m^-3), decreasing to >0.2 mg m^-3 in the vicinity of the subtropical gyre, south of 40°N. The nitracline was associated with a shoaling of the pycnocline in the northern latitudes. At 7°N, high chlorophyll concentrations (approximately 0.5 mg m^-3) and enhanced primary productivity (375.5 mg C m^-2 d^-1) were associated with a lens of fresh Amazon River Water.

Friedman, H.A. Hurricane names. Weather Tips, 1-2 (1990).

No abstract.

Gallagher, M.S., T.P. Carsey, and M.L. Farmer. Peroxyacetyl nitrate in the North Atlantic marine boundary layer. Global Biogeochemical Cycles, 4(3):297-308 (1990).

An automated system utilizing packed column gas chromatography and electron capture detection for the determination of peroxyacetyl nitrate (PAN) is described. The system was calibrated with a cryogenic PAN sublimation device, a molybdenum catalyst, and a chemiluminescent nitric oxide detector. Computer control of the analysis resulted in an analytical precision level of ~1%. A total of 1,178 PAN measurements were made from August 6 to September 5, 1988, in the marine boundary layer during the GCE/CASE/WATOC cruise (66°N to 7°N). Overall, PAN concentrations were highest at high latitudes (up to 40 ppt); PAN levels in the lower latitudes of the cruise track were usually <10 ppt. A number of episodes of elevated PAN are described which were characterized by elevated radon concentrations and a discernible diurnal cycle in the PAN concentration. These higher PAN levels are attributed to air masses with some continental influence, and to the enhanced stability of PAN at the cooler temperatures characteristic of the sub-Arctic region. In aged air masses of marine origin, PAN concentrations were significantly less and did not display diel changes; this is interpreted as a measure of the "background" PAN signal.

Galloway, J.N., W.C. Keene, A.A.P. Pszenny, D.M. Whelpdale, H. Sievering, J.T. Merrill, and J.F. Boatman. Sulfur in the western North Atlantic Ocean atmosphere: Results from a summer 1988 ship/aircraft experiment. Global Biogeochemical Cycles, 4(4):349-365 (1990).

To investigate the relative importance of anthropogenic versus marine sources of sulfur in the North Atlantic Ocean troposphere, sulfur species were measured from aircraft, ship, and island-based platforms as part of the Global Change Expedition/Coordinated Air-Sea Experiment/Western Atlantic Ocean Experiment conducted during the summer of 1988. Four synoptic meteorological cases were examined: flow from highly populated North America; lightly populated North America; tropical oceanic regions; and polar oceanic regions. Literature values suggest that 2-10 mol^-2 day^-1 of (CH₃)₂S are emitted from the ocean to the atmosphere in marine regions associated with the first three synoptic cases. Data from this experiment indicate that 36, 16, and 14 mol^-2 day^-1, for the highly populated North America, lightly populated North America, and tropical oceanic region synoptic cases, respectively, were deposited to the ocean's surface. Differences between previously estimated natural emissions and calculated deposition suggest that anthropogenic sources of sulfur contribute significantly to sulfur deposition for these cases. The sulfur deposition rate for the polar oceanic region's synoptic case was 20 mol^-2 day^-1. Given the larger range of literature values for the corresponding (CH₃)₂S emission rate (1-14 mol^-2 day^-1), however, the relative importance of the non-marine S source is less certain in this case.

Gamache, J.F. Microphysical observations in summer MONEX convective and stratiform clouds. Monthly Weather Review, 118(6):1238-1249 (1990).

Two-dimensional images of ice particles observed by a NOAA WP-3D research aircraft during the Summer Monsoon Experiment (SMONEX) are examined. These images were obtained in the temperature interval from -25°C to 0°C. The particle structures and size distributions found in convective and stratiform clouds are compared. Branched crystals were located predominantly in stratiform clouds while column-shaped crystals were located commonly in both stratiform and convective clouds. Stratiform clouds, particularly those observed at temperatures warmer than -7°C, had a much greater percentage concentration of large ice particles (>0.8 mm in diameter), and many of these ice particles were aggregates or branched crystals. The importance of aggregation and deposition above the melting level in stratiform clouds is strongly suggested by these findings. Ice particle number concentrations measured with the cloud probe were often very high in convective clouds, with a maximum value of approximately 800 L^-1. The average convective-cloud concentration was approximately 230 L^-1, while the average concentration in the stratiform clouds was approximately 20 L^-1. Liquid water was almost completely absent in the convective updrafts, at temperatures between -10°C and -22°C. This suggests that the convective updrafts may have been nearly completely glaciated, and the microphysics were dominated by deposition. The high particle concentrations in the convective updrafts suggest that the updrafts may provide most of the ice particles found in the stratiform cloud. Significant modification in particle structures and size distributions has occurred, however, by the time these suspended particles fall out of the stratiform clouds. These modifications appear to arise from aggregation and deposition.

Garzoli, S.L., and C. Simionato. Baroclinic instabilities and forced oscillations in the Brazil/Malvinas confluence front. Deep-Sea Research, 37(6A):1053-1074 (1990).

Observations collected at the confluence between the Brazil and Malvinas Currents are analyzed to study the high-frequency oscillations in the range of periods from 55 to 2 days. The variability in time and space of the thermohaline front originates at the confluence. The meandering of the Brazil Current after the encounter and the presence of an abrupt shelf break create the conditions for the generation of baroclinic and internal waves. Analysis of time-series of dynamic height, wind magnitude, and position of the front indicates the following: in the band from 20 to 55 day periods, two waves propagate with similar characteristics but in the opposite direction; neither of these waves appears to be forced by the wind. The westward-propagating wave (T=37.4 days) is related to the position of the front and is assumed to be forced by its north-south displacement. The eastward-propagating wave (T=29.1 days) has the characteristics of a topographic Rossby wave.

Georges, T.M., and D.R. Palmer. Report on the workshop: Application of ocean acoustic remote sensing to climate monitoring held in Boulder, Colorado on June 7-8, 1990. NOAA Technical Memorandum, ERL WPL-185 (PB91-105981), 13 pp. (1990).

The focus of the workshop is on acoustic propagation modeling and experiment simulation. Broader questions are discussed as well, including climatic needs for monitoring ocean variability and the suitability of ocean acoustics for doing so. The workshop was structured around five "Discussion Topics" and associated scientific questions, which were distributed with the workshop invitation and were designed to stimulate discussion. The two days of discussion were divided into five sessions, each moderated by a discussion leader. The principal discussion results and conclusions are given. The "Discussion Topics" are as follows: Relevance to climate studies; The Heard Island project; Propagation modeling-Theory; Interpreting acoustic measurements; Experiment simulation.

Giese, G.S., D.C. Chapman, P.G. Black, and J.A. Fornshell. Causation of large-amplitude coastal seiches on the Caribbean coast of Puerto Rico. Journal of Physical Oceanography, 20(9):1449-1458 (1990).

Sea-level oscillations at supertidal frequency with amplitudes of the order of the mean tidal range have been reported from the Caribbean coast of Puerto Rico. Analysis of a 10-year time series of digital tide data from Magueyes Island, Puerto Rico, demonstrates that sea-level variance at the fundamental normal mode (seiche) frequency of the shelf has a pronounced fortnightly distribution with a maximum occurring 6-7 days after new and full moon. The seiche variance also shows a bimodal seasonal distribution with an inverse relationship to easterly wind stress. It is argued that the seiches are excited by internal waves generated by strong tides in the southeastern Caribbean. Support is provided by airborne radar imagery showing sea-surface patterns suggesting the presence of internal waves near the southern Aves Ridge, and by the results of two field experiments, carried out during times when large-amplitude seiches were expected, to research for evidence of internal wave forcing near the shelf break. During the first experiment, large negative-amplitude, pulse-like internal waves were recorded 6 km seaward of the shelf break during a period of strong seiche activity. Such pulses were not observed during the second experiment. However, high-frequency temperature variance 2.3 km seaward of the shelf break, possibly resulting from internal surf, increased with depth and reached a maximum 6-7 days following new moon, again suggesting the presence of internal waves. The 10-year time series analysis shows that large tides are necessary, but not sufficient, to generate high seiche activity. This is supported by the two field experiments; during the first, large-amplitude seiches occurred as expected, while during the second experiment they did not. We suggest that this behavior is related to variations in stratification, which, in turn, alter the energy transfer from tides to seiches.

Gray, W.M., C.W. Landsea, P.W. Mielke, and K.J. Berry. Forecasting Atlantic seasonal hurricane variability. Proceedings, 15th Annual Climate Diagnostics Workshop, Asheville, NC. NOAA, 456-461 (1990).

No abstract.

Hallett, J., and P.T. Willis. Development of precipitation in isolated maritime cumulus. Preprints, Conference on Cloud Physics, San Francisco, CA, July 23-27, 1990. American Meteorological Society, Boston, 74-79 (1990).

No abstract.

Hansen, A.D.A., R.S. Artz, A.A.P. Pszenny, and R.E. Larson. Aerosol black carbon and radon as tracers for air mass origin over the North Atlantic Ocean. Global Biogeochemical Cycles, 4(2):189-199 (1990).

We present results from the Global Change Expedition/Coordinated Air-Sea Experiment/Western Atlantic Ocean Experiment (GCE/CASE/WATOX) research cruise conducted from July to September 1988 in the North Atlantic Ocean aboard the NOAA Ship Mt. Mitchell. We examine the correlations between measurements of aerosol black carbon (BC, a tracer for combustion emissions), radon 222 (Rn, a tracer for natural emissions from land masses), and calculated isentropic back trajectories from the ship's position during two portions of the cruise that circled the North Atlantic Ocean. The results suggest four distinct categories of origin of the sampled air mass, with trajectories connecting back to different geographical areas: case A, trajectories from inhabited land, with the air mass containing strongly correlated BC and Rn; case B, trajectories from uninhabited (far northern) land, with Rn but little BC; case C, contaminated marine air, with little Rn but moderate BC, correlated with observations of combustion sources (other ships, etc.) in the vicinity; and case D, air masses of remote marine origin, with low BC and low Rn content. The requirements of the trajectory analyses lead to an improved understanding of the transport pathways across the ocean. We conclude that real-time measurements of aerosol black carbon and radon, coupled with timely meteorological analyses, can be a powerful indicator of air mass origin both retrospectively and during the course of an experiment to assist in the scheduling of other measurements.

Hansen, D.V. Physical aspects of the El Niño event of 1982-1983. In Global Ecological Consequences of the 1982-1983 El Niño-Southern Oscillation, P.W. Glynn (ed.). Elsevier Oceanography Series, 52, 1-20 (1990).

El Niño events are marked by the appearance of anomalously warm ocean waters and unusual rainfall in normally arid coastal regions of Ecuador and Peru. During the past century such events have occurred at about four-year intervals on average, and nine of the events have been described as strong or very strong. In the spring of 1982 the heavy rainfall that normally characterizes the Indo-Pacific archipelago began to shift eastward toward the central Pacific. During the following year the region of anomalous rainfall traversed the ocean to the coast of South America, in phase with anomalous winds, currents, and sea surface temperatures. At the peak of the event in the eastern tropical Pacific, Peru and Ecuador experienced record-setting rainfall leading to flooding and avalanches, near surface ocean currents reversed from their normal direction, sea surface temperature rose to 5°C or more above normal, the thermocline plunged to 100 m or more below normal, and sea level rose to nearly half a meter above normal. Upon reaching the coast, many of the oceanic perturbations propagated poleward along the continental margins in both hemispheres, carrying the signs and effects of El Niño to middle and high latitudes in the Pacific. The magnitude of this event made it the "event of the century" in most variables, and the event of several centuries in some. The magnitude of perturbation of the atmosphere in the tropical Pacific sector certainly carried anomalies also in distant regions of the atmosphere, and thereby secondarily in other parts of the ocean. At greater distance, however, it becomes increasingly difficult to distinguish between anomalies resulting from El Niño and those arising from other kinds of variations of the atmospheric circulation.

Hansen, D.V. Surface current and temperature patterns in the western tropical Pacific. In Air Sea Interaction in the Tropical Western Pacific, J. Chao and J. Young (eds.). China Ocean Press, Beijing, 121-128 (1990).

No abstract.

Hastie, D.R., S. Malle, D.L. Toom, D.M. Whelpdale, W.C. Keene, J.N. Galloway, J. Maben, and A.A.P. Pszenny. Inorganic nitrogen over the western North Atlantic Ocean. Global Biogeochemical Cycles, 4(3):267-278 (1990).

The concentrations of the reactive nitrogen species NO₂, NO_x (=NO + NO₂), NO_y (the sum of all compounds of nitrogen and oxygen with the exception of N₂O), particulate NO₃^-, and volatile NO₃^- were measured from ship and aircraft platforms over the western North Atlantic Ocean as part of the GCE/CASE/WATOX experiment. Air masses sampled were divided into continentally influenced and typical marine on the basis of trajectories, and radon and black carbon measurements. From the NO₃^- measurements on size separated aerosol and the altitude variations of volatile NO₃^- and particulate NO₃^-, a significant interaction between volatile NO₃^- and sea salt aerosol was indicated. The average marine concentrations measured were 18 nmol^-3 for NO₂, 29 nmol^-3 for NO_x, 46 nmol^-3 for NO_y, and 10 nmol_-3 for total inorganic NO₃^-. The reactive nitrogen species were present at concentrations some 40 times those encountered in the remote Pacific Ocean, where the inorganic NO₃^- was only three times higher.

Hitchcock, G.L., D.B. Olson, G.A. Knauer, A.A.P. Pszenny, and J.N. Galloway. Horizontal diffusion and new production in the Sargasso Sea. Global Biogeochemical Cycles, 4(3):253-265 (1990).

Estimates of vertical particulate carbon flux and inorganic nitrogen input from rain events were evaluated in relation to horizontal diffusion during a short-term (four days) study in the Sargasso Sea. Productivity (300 mg C^-2 d^-1) and particulate organic C flux (f-ratio of 0.17) from sediment trap arrays were similar to those recently documented in this region. The drifters traversed the periphery of a small anticyclonic eddy, and an estimate of horizontal diffusivity (~3 to 10 x 10⁴ cm² s^-1) was derived from relative drifter separation. The corresponding length scale (a few kilometers) and time scale (a day) is related to the effective collection area from which drifting sediment traps can sample the surrounding environment. Measurements of inorganic nitrogen from two rain events were similar to those in a more extensive series of observations from Bermuda. The summer Bermuda data are used to evaluate the inorganic nitrogen input to the oligotrophic surface waters with respect to phytoplankton uptake rates and horizontal diffusion. For small, convective rain events, diffusion may be as important as phytoplankton uptake in reducing nitrogen concentrations to ambient nanomolar levels.

Houze, R.A., B.F. Smull, and P.P. Dodge. Mesoscale organization of springtime rainstorms in Oklahoma. Monthly Weather Review, 118(3):613-654 (1990).

Radar reflectivity and rain gage data obtained during six springtimes indicates the types of mesoscale organization that occur in association with major rain events in Oklahoma (at least 25 mm of rain in 24 h over an area exceeding 12,500 km²). In these storms, the primary rain area is found to be a contiguous region of precipitation tens to hundreds of kilometers in scale that consists partly of deep convection and partly of stratiform rain. The patterns of rain formed by the convective and stratiform areas comprise a continuous spectrum of mesoscale structures. About two-thirds of the cases examined exhibited variations on the type of organization in which convective cells arranged in a moving line are followed by a region of stratiform rain. Storm organization was graded according to the degree to which it matched an idealized model of this "leading-line/trailing-stratiform" structure. The precipitation pattern was further graded according to whether its structure was relatively symmetric with respect to an axis normal to and passing through the midpoint of the line, or asymmetric, in which case the storm was biased toward having stronger, more discrete convective structure at the upwind (south or southwestern) end of the line and/or the most extensive stratiform precipitation behind the downwind (north to northeastern) end of the line. About one-third of the cases examined displayed much more chaotic, unclassifiable arrangements of convective and stratiform areas. Among the cases with leading-line/trailing-stratiform structure, severe weather was most frequent in systems with (1) a strong degree of leading-line/trailing-strataiform structure, in which a solid, relatively uniform, arc-shaped line had stratiform rain centered symmetrically behind it, and (2) a weaker degree of leading-line/trailing-stratiform structure in which a southwest-northeast line was biased toward having narrow, intensely convective, irregularly spaced cell structure at its southwestern (upwind) end and stratiform rain confined to the region behind the broader northeastern (downwind) portion of the line. Although all mesoscale organization types were characterized by all types of severe weather, the type (2) cases were the most prolific category in terms of tornado and hail production, while type (1) cases were prone to be associated with flooding. The chaotic, unclassifiable cases, which exhibited no line organization, had just as much severe weather as the cases with line organization, but were more likely to produce hail and somewhat less likely to produce tornadoes and flooding than the systems with line structure. Major rain events occurred whenever a mesoscale convective complex (MCC) was dissipating or merely skirting the area. However, 75% of the major rain events occurred under cloud shields that failed to meet the MCC criteria explicitly, although they often resembled MCCs qualitatively. No particular type of mesoscale radar-echo organization was favored when cloud shields meeting the MCC criteria were observed. A slight preference for the more chaotic type of organization was suggested; however, the data sample is not large enough for this finding to be regarded as conclusive. Mean soundings and hodographs generally show no sign of a low-level jet in environments associated with chaotically arranged rain areas that lacked any line structure. On the other hand, a low-level jet and resulting curved hodograph were typically associated with cases in which line organization was evident. The wind shear in the low to midtroposphere, the bulk Richardson number, and other familiar parameters characterizing squall line environments are consistent with results from recent modeling studies. When leading-line/trailing-stratiform structure was present, the cross-line shear in the environment was of a magnitude associated with model simulations in which a rearward sloping updraft circulation favorable to trailing-stratiform anvil formation quickly develops. The along-line componentt of shear was greater when the squall system structure was of the asymmetric type and the degree of leading-line/trailing-stratiform structure was not as strong, i.e., in those mesoscale systems favoring tornado occurrence.

Incze, L.S., P.B. Ortner, and J.D. Schumacher. Microzooplankton, vertical mixing and advection in a larval fish patch. Journal of Plankton Research, 12(2):365-379 (1990).

A large (~30 x 75 km) patch of larval walleye pollock, Theragra chalcogramma, was located south of the Alaska Peninsula during May 1986. A drifter deployed in this patch followed an anticyclonic path consistent with dynamic topography. Changes in community composition and vertical distribution of microzooplankton >40 µm were sampled for four days alongside this drifter to examine feeding conditions for larvae. Biological and physical changes during the first two calm days revealed substantial small-scale variability within the larger circulation pattern. Changes during the last two days were dominated by vertical mixing due to strong winds. Despite mixing, prey concentrations remained adequate for feeding by larval pollock as determined by laboratory studies. A satellite-tracked drifter replaced the first drifter and was still located within the patch six days later. Overall distributions of larvae and movements of the drifters show a net translation of 7.8 km day^-1 southwestward, but details of the study reveal complex interactions between coastal waters and a coastal current. During the 10-day period, there was an increase in standard length of the larval fish population of 0.13 mm day^-1 and a decline in abundance of ~7.6% day^-1. Both calculated rates must be underestimates due to continuing recruitment of small larvae from hatching eggs.

Karson, J.A., and P.A. Rona. Block-tilting, transfer faults, and structural control of magmatic and hydrothermal processes in the TAG area, Mid-Atlantic Ridge, 26°N. Geological Society of America Bulletin, 102(12):1635-1645 (1990).

Seven Alvin dives (14 km total) and numerous deep-towed camera traverses using ANGUS and NOAA camera systems provide dense coverage of a 12 km² portion of the eastern wall of the Mid-Atlantic Ridge in the TAG area (26°N latitude). These data, in conjunction with recent Soviet Mir submersible data, provide important constraints on the tectonic, magmatic, and hydrothermal history of this spreading center segment. Active hydrothermal venting occurs near the junction of the median valley floor and eastern median valley wall and appears to be tectonically controlled by the intersection of major fault zones. An east-west fault-line scarp interpreted as an accommodation zone intersects escarpments associated with 020°-trending (ridge-parallel) normal faults that bound the median valley floor. The accommodation zone permits differential extension and rotation between major crustal blocks to the north and south. On the basis of the distribution of tilted chalk beds and geochemical anomalies in sediments, this fault zone has been intermittently active for at least 5 x 10⁴ yr. The accommodation zone has apparently provided a conduit of high permeability oriented at a high angle to the ridge axis. Observations and samples from areas surrounding active and inactive vent sites provide evidence for three distinct episodes for hydrothermal outflow driven by separate magmatic events. The geometry of this active system may have implications for the location of hydrothermal systems in active spreading regimes and for massive sulfide exploration in ophiolite terranes.

Keene, W.C., A.A.P. Pszenny, D.J. Jacob, R.A. Duce, J.N. Galloway, J.J. Schultz-Tokos, H. Sievering, and J.F. Boatman. The geochemical cycling of reactive chlorine through the marine troposphere. Global Biogeochemical Cycles, 4(4):407-430 (1990).

Heterogeneous reactions involving sea-salt aerosol in the marine troposphere are the major global source for volatile inorganic chlorine. We measured reactant and product species hypothesized to be associated with these chemical transformations as a function of phase, particle size, and altitude over the North Atlantic Ocean during the summer of 1988. Concentrations of HCl were typically less than 1.0 ppbv near the sea surface and decreased with altitude and with distance from the U.S. east coast. Concentrations of Cl volatilized from aerosols were generally equivalent to the corresponding concentrations of HCl and ranged from less than detection limits to 125 nmol m^-3 STP. Highest absolute and percentage losses of particulate Cl were typically associated with elevated concentrations of anthropogenic combustion products. Concentrations of product nss SO₄^2- and NO₃^- in coarse aerosol fractions indicate that, on average, only 38% of measured Cl- deficits could be accounted for by the combined effects of acid-base desorption and reactions involving nonacidic N gases. We hypothesize a mechanism for the Cl loss initiated by reaction of O₃ at sea-salt aerosol surfaces, generating Cl₂, followed by rapid photochemical conversion of Cl₂ to HC1 via Cl atoms (Cl•) and eventual recapture of HCl by the aerosol. Simulations with a zero-dimension (0-D) photochemical model suggest that oxidation by Cl• may be an important tropospheric sink for dimethyl sulfide and hydrocarbons. Under low NO_x conditions, the rapid cycling of reactive Cl would provide a catalytic loss mechanism for O₃, which would possibly explain the low O₃ concentrations often observed above the world's oceans.

Lalou, C., G. Thompson, M. Arnold, E. Bricher, E. Druffel, and P.A. Rona. Geochronology of TAG and Snakepit hydrothermal fields, Mid-Atlantic Ridge: Witness to a long and complex hydrothermal history. Earth and Planetary Science Letters, 97(1-2):113-128 (1990).

Geochronological studies of a large number of precipitates from the TAG hydrothermal field and of few samples from Snakepit hydrothermal field of the Mid-Atlantic Ridge show intermittent repeated hydrothermal events at both sites. ²¹⁰Pb/Pb and ²³⁰Th/²³⁴U measurements of sulfides, iron and manganese oxides, and ¹⁴C measurements of carbonates combined with observations of hydrothermal events recorded as discrete layers in sediment cores provide the basis for unravelling the temporal history of the fields. The TAG field shows intermittent activity over the past 120,000 years as evidenced by ages of low-temperature Mn oxides. The presently active black smoker mound first formed about 40,000-50,000 years ago with precipitation of massive sulfides. It has had intermittent, pulsed high-temperature activity every 5000-6000 years over the past 20,000 years which may reflect renewed magmatic activity at the ridge axis. Fluid flow is focused at the mound site by structural and tectonic control suggested by the intersection of north-south ridge parallel lystric normal faults and an east-west transform fault. Periods of inactivity are marked by covering of the mound with pelagic carbonate ooze which is probably partially dissolved and reprecipitated as aragonite at the end of each high-temperature event. The Snakepit field had an initial event about 4000 years ago, probably shortly after the eruption of the volcanic ridge on which it sits. A recent renewal, still presently active, was probably initiated by recent fissuring of the volcanic pile.

Leaman, K.D., and J.E. Harris. On the average absolute transport of the Deep Western Boundary Currents east of Abaco Island, the Bahamas. Journal of Physical Oceanography, 20(3):467-475 (1990).

Data obtained from a line of absolute current profiler (PEGASUS) and CTD stations at 26.5°N, east of Abaco Island in the northern Bahamas, are used to estimate the average transport, and overall level of variability, of the deep (below 800 m) southward flow associated with the so-called "Deep Western Boundary Current"(DWBC) at this latitude. From April 1985 to September 1987, a total of 11 sections were made along a line extending from near the island boundary to 85 km offshore as part of the Subtropical Atlantic Climate Studies (STACS) program. In all but two cases (when PEGASUS data were obtained over the total depth), absolute velocities were determined from 0 to about 3000 db while CTD derived relative velocities were determined over the total depth. Using the combined datasets, it is possible to reference the relative geostrophic velocity with PEGASUS data, thereby obtaining an estimate of the absolute southward transport of the deep flow. The average value of transport determined in this manner is about 35 Sv (1 Sv 10⁶ m³ s^-1. Most of this large transport is located in a deep (2000 m) offshore core, with average southward velocities of 0.20 m s^-1. This core is not co-located with the "Deep Western Boundary Current" core as defined by tracer studies. It is suggested here that this core may either be part of a southern deep recirculation gyre similar to those proposed farther north (e.g., nearer the Gulf Stream) or alternatively represents the augmented DWBC flow found in some theoretical models.

Lierhiemer, L.J., P.C. Fiedler, S.B. Reilly, R.L. Pitman, L.T. Ballance, S.C. Beavers, G.G. Thomas, and D.W. Behringer. Report of ecosystem studies conducted during the 1989 eastern tropical Pacific dolphin survey on the research vessel David Starr Jordan. NOAA Technical Memorandum, NMFS-SWFC-139, 118 pp. (1990).

No abstract.

Lierhiemer, L.J., P.C. Fiedler, S.B. Reilly, R.L. Pitman, L.T. Ballance, S.C. Beavers, and D.W. Behringer. Report of ecosystem studies conducted during the 1989 eastern tropical Pacific dolphin survey on the research vessel McArthur. NOAA Technical Memorandum, NMFS-SWFC-140, 123 pp. (1990).

No abstract.

Long, R.B., W.C. Thacker, and S.-M. Hwang. Fitting a general ocean circulation model to observations: A progress report. Proceedings, International Symposium on Assimilation of Observations in Meteorology and Oceanography, Clermont-Ferrand, France, July 9-13, 1990. World Meteorological Organization, 65-70 (1990).

The assimilation method known as model fitting or as the adjoint method procedure finds the solution to the numerical model equations reproducing best all available observations of whatever type and wherever located in space and time. The model fitting procedure of Thacker and Long (1988) and Long and Thacker (1989), which is functionally the same as the so-called adjoint method, is set forth. Its application to the GFDL-GCM is illustrated for the case of two simple numerical experiments on the AOML VAX-8700, which simulates schematically the bathymetry of the North Atlantic, and on the CYBER-205. The experience indicates that although computationally expensive, the model fitting as a procedure is workable and can provide an optimal interface between large complicated numerical models and data.

Lord, S.J., and J.L. Franklin. The environment of Hurricane Debby (1982). Part II: Thermodynamic fields. Monthly Weather Review, 118(7):1444-1459 (1990).

A three-dimensional analysis of temperature and relative humidity in the environment of Hurricane Debby (1982) has been completed. Observations from Omega dropwindsondes (ODWs) within 1000 km of the storm have been combined with rawinsondes over the continental United States and the Caribbean and with observations from surface ships and aircraft data where possible. The temperature and relative humidity analyses, together with wind analyses from a previous study, form a dataset that can be used as an initial condition in a multilevel prognostic model when combined with analyses over area larger than our analysis domain. In this paper a series of diagnostic tests has been applied to the dataset to evaluate its performance without using a prognostic model. These tests include horizontal maps of the moist convective instability, calculation of the heat and moisture budgets in the vicinity of Bermuda, which was 350 km to the northeast of the storm center, and diagnosis of precipitation from these budgets and from the Arakawa-Schubert cumulus parameterization. Results show that the horizontal distribution of moist convective instability is strongly affected by the low-level moisture field upstream of the main inflow region to the storm. The total surface heat flux, estimated with a bulk aerodynamic method, matches the vertically integrated eddy flux of moist static energy to within observational errors. Precipitation estimates from the budgets give rates of approximately 20 mm day^-1, which are consistent with an estimated rate from radar. Partition of the rainfall rate into convective scale and resolvable scale (stratiform) shows about equal contributions. Our results lead us to believe that, within the limitations determined by the horizontal distribution of the observations, the final dataset for Hurricane Debby provides a realistic depiction of the various physical processes that were occurring in Debby's environment. Future work will include data sensitivity experiments with a three-dimensional forecast model.

Marks, F.D. Radar observations of tropical weather systems. In Radar in Meteorology: Battan Memorial and 40th Anniversary Radar Meteorology Conference, D. Atlas (ed.). American Meteorological Society, Boston, 401-425 (1990).

No abstract.

Marks, F.D., and P.G. Black. Close encounter with an intense mesoscale vortex within Hurricane Hugo (September 15, 1989). Preprints, 4th Conference on Mesoscale Processes, Boulder, CO, June 25-29, 1990. American Meteorological Society, Boston, 114-115 (1990).

No abstract.

Maul, G.A., and C.N.K. Mooers. Report on INSMAP'90: The Second International Symposium on Marine Positioning. Marine Geodesy, 14(3-4):169-175 (1990).

INSMAP'90, the second in a series of quadrennial international symposia on marine positioning, was held October 15-19, 1990. The University of Miami's Rosenstiel School of Marine and Atmospheric Science hosted the meeting. INSMAP'90 focused attention on special problems associated with positioning in the marine environment, providing a timely forum and opportunity for in-depth discussions and exchange of ideas, identified immediate and future requirements and applications, and enhanced interdisciplinary and interagency collaboration. Over 100 scientists and students attended. More than 60 papers were presented, there were five symposium-wide lectures, five workshops (each with several lectures), and a tour of the U.S. Naval Observatory Alternate Time Service and VLBI/GPS facility, where all the exhibitors set up their demonstrations. Most of the papers and addresses are available in a single hard-bound volume from the MTS.

Maul, G.A., K. Hanson, and H.F. Bezdek. A note on determining potential anthropogenic signals in sea level: An example from Florida and juxtaposed areas. In Towards an Integrated System for Measuring Long-Term Changes in Global Sea Level, H.F. Eden (ed.). Joint Oceanographic Institutions, Inc., Washington, D.C., 17-29 (1990).

No abstract.

Maul, G.A., D.A. Mayer, and M.H. Bushnell. Statistical relationships between local sea level and weather with Florida-Bahamas cable and Pegasus measurements of Florida Current volume transport. Journal of Geophysical Research, 95(C3):3287-3296 (1990).

Straits of Florida sea level is studied as a measure of Florida Current volume transport because sea level provides an independent time series both (1) for detecting changes in the calibration of the Florida-Bahamas submarine cable which has been operating since 1982, and (2) as a measure of the strength of the Gulf Stream system dating to the 1930s when cable measurements were not available. Accordingly, tide gauge records from Haulover Beach (Miami) and Lake Worth, Florida, and from Cat Cay and Settlement Point, The Bahamas, together with Miami weather and cable voltage, are correlated with each other and with discrete volume transport estimated from all Pegasus data taken during the intensive 1982-1984 Subtropical Atlantic Climate Studies (STACS) observations. Time domain linear correlation coefficients between these 132 Pegasus values and cable voltage observations, Cat Cay minus Haulover Beach sea level, and Haulover Beach sea level only, are 0.91, 0.55, and -0.76, respectively, but for the 1982-1988 time series, Cat Cay minus Haulover Beach is better correlated with cable observations (0.62) than is Haulover Beach alone (-0.44). Frequency domain modeling computations reveal that the sea level and cable data are organized in such a way that most of their energy lies below frequencies of 30^-1 cycles per day (cpd). In a subseasonal band (up to and including the semiannual frequency) 49% of the cable energy and 59% of the Haulover Beach energy can be accounted for using 30-day low-passed data. A subseasonal frequency response function has been tentatively identified that relates both Florida sea level and Bahamas-Florida sea level difference to cable observations and can successfully account for more than 60% of the observed cable variance (standard error is ±1 × 10⁶ m³ s^-1). Further, negative Florida sea level only and Bahamas-Florida sea level difference have different phase relationships with cable observations; it is suggested that steric effects could be responsible for the phase shifts.

Mayer, D.A., R.L. Molinari, and R.H. Weisberg. Analysis of volunteer observing ship temperature fields in the tropical Atlantic Ocean. Oceanologica Acta, 13(3):257-264 (1990).

Volunteer observing ship data collected during the FGGE year in 1979 and data from in situ moorings deployed during the SEQUAL/FOCAL experiment in 1983-1984 are used to estimate the dominant temporal and spatial scales of SST variability in the equatorial Atlantic Ocean. Two-dimensional Fourier transforms show that enhanced energy levels in a wave number and frequency band of 1924^-1-825^-1 cycles/km and 37^-1-21^-1 cycles/day respectively, are associated with organized SST structures with wave-like oscillations that are consistent with barotropic instabilities. The oscillations appear on the equator between 1°S and 1°N eastward of 25°W shortly after the springtime intensification of the easterly wind stress and persist into August. They are characterized by a westward phase propagation of about 50 cm s^-1 and a pattern that progresses eastward at approximately 30 cm s^-1.

Molinari, R.L., E. Johns, and J.F. Festa. The annual cycle of meridional heat flux in the Atlantic Ocean at 26.5°N. Journal of Physical Oceanography, 20(3):476-482 (1990).

Total meridional heat flux through a zonal oceanic section at 26.5°N in the Atlantic Ocean is computed from hydrographic, direct current, and surface wind observations. The oceanic current and temperature fields are decomposed into depth-averaged and depth-dependent (including Ekman and geostrophic) components to perform the calculation. The mean annual heat flux is estimated to be 1.21 ± 0.34 PW. Mean monthly values of net heat flux are also computed from the data. The annual cycle of net heat flux determined from these values ranges from a minimum of 0.69 PW in February to a maximum of 1.86 PW in July. Thus, in contrast to an earlier estimate of the annual cycle of oceanic heat flux derived indirectly from surface energy fluxes and upper-layer heat content changes, there is no net southward heat flux during the fall. Results from a simulation of the circulation of the North Atlantic give an annual cycle of heat flux similar to our calculation with a summer maximum and winter minimum. However, the simulated mean value and range of the annual cycle are less than observed.

Molinari, R.L., D. Olson, and G. Reverdin. Surface current distributions in the tropical Indian Ocean derived from compilations of surface buoy trajectories. Journal of Geophysical Research, 95(C5):7217-7238 (1990).

Three different satellite-tracked drifting buoy data sets are compiled and used to generate a monthly climatology of surface currents in the tropical Indian Ocean. Buoys were deployed between 1975 and 1987. The data density is maximum on and near the equator and decreases poleward. Drift characteristics of the different buoy configurations are compared using a structure function analysis. The differences in windage effects are consistent with the buoy designs and small compared with the signals studied. The currents in the tropical Indian Ocean during boreal winter and spring can be characterized as two counterrotating gyres. A southern clockwise rotating gyre is bounded on the south by the South Equatorial Current (SEC) and on the north during winter by the Equatorial Countercurrent (ECC) and during spring by the Equatorial Jet (EJ). A northern counterclockwise rotating gyre is bounded on the south by the ECC and EJ, depending on season, and on the north by the North Equatorial Current (NEC). The two gyre systems break down during boreal summer. During this season, the SEC is located closer to the equator, and the NEC is replaced by the eastward flowing Indian Monsoon Current (IMC). The western boundary circulation becomes more complicated from late spring through early autumn with the observation of two intense smaller scale gyres. The large-scale southern gyre reappears during boreal autumn with the reappearance of the EJ. The northern gyre begins to reappear in December, with the reversal of the IMC and the reappearance of the NEC. The monthly buoy speeds are compared with a monthly climatology generated from ship drift reports. Differences between the two climatologies are, in general, small except in regions of few trajectories. The annual cycles in amplitudes and phases of the major currents in the region are thus comparable.

Ooyama, K.V. A thermodynamic foundation for modeling the moist atmosphere. Journal of the Atmospheric Sciences, 47(21):2580-2593 (1990).

With advances in numerical modeling of the atmosphere, we have experienced that the return to the first principles of physics often enables a model to cope more easily with the complexities of the real atmosphere. The return to the primitive equations of motion from historical balance approximations is an example. This paper proposes a way to return to the "primitive" form of moist thermodynamics, in which prediction is made strictly in terms of conservative properties, such as mass and entropy. There is no conservation law that would apply directly to temperature or pressure. These intensive properties, therefore, should be diagnostically determined by thermodynamics, from the predicted conservative properties. The scope of the paper is limited to the thermodynamics of reversible processes. Irreversible processes, which would make a model alive with real weather, are not discussed here, since each of them requires a separate empirical treatment. It is shown, however, that the proposed formulation of thermodynamics facilitates modularization of various approximations within a model, and among models. For example, both the hydrostatic and nonhydrostatic models can be built under an identical design, differing only in the manner of calculating vertical motion. The proposed formulation is extended to include the ice phase within reversible thermodynamics. Also discussed are numerical problems in the spatial representation of thermodynamic discontinuities, which are caused by the phase transition of water substance.

Palmer, D.R., and P.A. Rona. Comment on "Acoustic Doppler current profiler observations of a mid-ocean ridge hydrothermal plume" by Thomson et al. Journal of Geophysical Research, 95(C4):5409-5412 (1990).

This paper discusses the use of Doppler sonar to image buoyant plumes from hydrothermal vents and the causes for various apparent anomalies in the observations.

Palmer, D.R., T.M. Georges, and R.M. Jones. Chaos in underwater acoustics. Proceedings, Fifth International Symposium on Acoustic Remote Sensing of the Atmosphere and Oceans, S.P. Singal (ed.). New Delhi, India, February 6-9, 1990. Tata McGraw-Hill, 210-215 (1990).

During numerical simulations of acoustic propagation in a weakly range-dependent, deterministic ocean, we find conditions that produce chaotic ray paths. Chaos is an instability which results from the nonlinear nature of the differential equations which determine the ray paths, rather than from externally imposed noise or randomness. It places a fundamental limitation on the range to which an acoustic field can be predicted. We also discuss some new methods for identifying chaotic rays which have advantages over the standard methods. Finally, we note the existence of chaotic rays for propagation in the Straits of Florida.

Palmer, D.R., T.M. Georges, and R.M. Jones. Classical chaos and the sensitivity of the acoustic field to small-scale ocean structure. Proceedings, First International Conference on Computational Physics, Boulder, CO, June 11-15, 1990. North Holland, 8-15 (1990).

Peng, T.-H. Climate change and atmospheric CO₂ variations. Proceedings of the Geological Society of China, 33(4):391-409 (1990).

A strong correlation between climate change and atmospheric CO₂ variations was revealed through measurements of paleoatmospheric CO₂ in air bubbles trapped in polar ice layers. It was shown that the atmospheric CO₂ increased from 200 to 280 ppm as climate changed from glacial to intergalcial conditions. Many hypotheses have been proposed to explain the cause of these atmospheric CO₂ changes. In most early hypotheses the marine biological activity was considered to be the main mechanism for transferring carbon within ocean-atmosphere-biosphere reservoirs. Unfortunately, these hypotheses have inherent problems of deficient O₂ concentration in glacial deep waters and changes of nutrient content accompanying climate change that are contrary to deep sea sediment records. However, two important factors became clear: (1) the ultimate source of the CO₂ change must lie in the sea, and (2) the most critical waters of the ocean are those at the surface in the polar region. Based on these factors and a recent requirement for an alkalinity increase derived from the observed nutrient deepening in the glacial Atlantic, a polar alkalinity hypothesis was proposed. The hypothesis suggests that the major cause for the 80-ppm change in CO₂ was a 75-µeq · kg^-1 drop in the salinity-normalized alkalinity of Antarctic surface waters at the close of glacial time. This drop stemmed in part from the reinitiation of the Atlantic conveyor circulation system (i.e., North Atlantic Deep Water) and in part from the shallowing of the ocean's nutrient maximum.

Peng, T.-H., T.L. Ku, J. Southon, C. Measures, and W.S. Broecker. Factors controlling the distribution of ¹⁰Be and ⁹Be in the ocean. In From Mantle to Meteorites, A Garland of Perspectives: A Festschrift for Devendra Lal, K. Gopalan, V.K. Gaur, B.L.K. Somayajulu and J.D. Macdougall (eds.). Indian Academy of Sciences, Bangalore, India, 201-204 (1990).

Observations show that while the concentration of ⁹Be in the deep sea is geographically uniform, that of ¹⁰Be increases from Atlantic to Antarctic to Pacific. Using a geochemical ocean box model calibrated by the radiocarbon distribution in the sea, we show that this situation requires (1) that ⁹Be be added preferentially to the Atlantic Ocean and (2) that the residence time for beryllium in the sea be comparable to the oceanic mixing time. Both requirements are consistent with what is known regarding the geochemistry of beryllium.

Peng, T.-H., W.M. Post, D.L. DeAngelis, V.H. Dale, and M.P. Farrell. Atmospheric carbon dioxide and the global carbon cycle: The key uncertainties. In Environmental Problems and Solutions, T.N. Veziroglu (ed.). Hemisphere Pub. Corp., New York, 17-38 (1990).

No abstract.

Piotrowicz, S.R., C.J. Fischer, and R.S. Artz. Ozone and carbon monoxide over the North Atlantic during a boreal summer. Global Biogeochemical Cycles, 4(2):215-224 (1990).

Ozone mixing ratios observed on a cruise from the east coast of North America to Bermuda, to Iceland, to the Azores, and terminating in Barbados in a boreal summer exhibit wide variability. Increases above a North Atlantic background of 10-20 ppbv appear to be associated with transport from terrestrial systems. In the central gyre of the North Atlantic and in the tropical North Atlantic, ozone mixing ratios below 10 ppbv are commonly observed when the air being sampled does not have a recent (10 days) history of terrestrial input. Carbon monoxide mixing ratios within the boundary layer vary latitudinally from an average of 124 ppbv in the westerlies to 88 ppbv in the tropical North Atlantic. Variability in the distribution of CO appears to be dominated by transport from terrestrial source regions.

Post, W.M., T.-H. Peng, W.R. Emanuel, A.W. King, V.H. Dale, and D.L. DeAngelis. The global carbon cycle. American Scientist, 78:310-326 (1990).

No abstract.

Powell, M.D. Boundary layer structure and dynamics in outer hurricane rainbands. Part I: Mesoscale rainfall and kinematic structure. Monthly Weather Review, 118(4):891-917 (1990).

Results of hurricane boundary layer experiments conducted in outer rainbands of Hurricanes Josephine (1984) and Earl (1986) are presented. Comparisons of precipitation and kinematic structures in these storms and in Hurricane Floyd (1981) indicate that principal rainbands have common characteristic mesoscale and convective-scale features in the boundary layer. The two-dimensional mesoscale structure suggests that these rainbands are made up of a linear aggregate of cellular reflectivity elements (on the inner, upshear side of the band) and stratiform rain (on the outer downshear side). The bands are oriented perpendicular to the shear above the boundary layer and cells move downband at about 85% of the density-weighed mean wind speed of the 0.2-6 km layer. The boundary layer windfield is strongly influenced by the rainband with alongband and crossband wind maxima located on the outer side of the band axis, and minima 4-8 km to the inner side. Maximum crossband convergence and cyclonic shear vorticity are also found to the inner side of the rainband axis. Updrafts and downdrafts are preferentially located on the inner side of the band axis, with some downdrafts spreading out at the surface. The band-relative positions of the updraft and perturbation pressure minimum suggest that the minimum may be produced by interaction of the wind shear and the updraft. Outer hurricane rainbands show many similarities to tropical squall lines; major differences are associated with propagation and the structure of the leading and trailing edges.

Powell, M.D. Boundary layer structure and dynamics in outer hurricane rainbands. Part II: Downdraft modification and mixed-layer recovery. Monthly Weather Review, 118(4):918-938 (1990).

Recent aircraft boundary layer measurements in the vicinity of principal hurricane rainbands have confirmed that convective downdrafts are capable of transporting cool, dry, low equivalent potential temperature air to the surface, wher the mixed layer is eliminated. The incorporation of this air into convection near the core of the storm may weaken the storm, depending upon the scale of the disturbance and the processes governing the recovery of the air while it is flowing toward the eyewall. This paper examines the thermodynamic characteristics of the boundary layer in outer convective hurricane rainbands, providing evidence for downdraft modification mechanisms and determining the extent to which disturbed boundary layer air may be restored on its trajectory to the storm.

Powell, M.D. Observations of boundary layer structure and mesoscale wind fields in a midlatitude marine rainband during GALE. Preprints, 4th Conference on Mesoscale Processes, Boulder, CO, June 25-29, 1990. American Meteorological Society, Boston, 55-56 (1990).

No abstract.

Powell, M.D., and P.G. Black. Meteorological aspects of Hurricane Hugo's landfall in the Carolinas. Shore and Beach, 58(4):3-10 (1990).

No abstract.

Powell, M.D., and P.G. Black. The relationship of hurricane reconnaissance flight-level wind measurements to winds measured by NOAA's oceanic platforms. Journal of Wind Engineering and Industrial Aerodynamics, 36(1):381-392 (1990).

A well-known problem in hurricane forecasting and in the administration of hazardous weather warnings and advisories concerns what adjustments to make to flight-level reconnaissance wind observations in order to make them representative of sustained surface winds. To solve this problem, a study was initiated comparing NOAA reconnaissance flight-level winds to 10 m level observations from NOAA's oceanic buoys and platforms. A data base was created that consisted of comparisons made whenever the aircraft observation was: (1) within 10 km radial separation from the surface platform (in a storm-relative coordinate system); (2) within ±4 h of the surface observation time; and (3) within ±2 h of the surface observation time. The data base contains all storms flown by NOAA aircraft in the vicinity of the Atlantic and Gulf of Mexico buoy network over the 11-year period from 1975-1986. Comparisons from these criteria are discussed in terms of the ratio of the buoy-measured wind speed (V_B) to the aircraft-measured wind speed V_A. Results indicate that the 10 m level surface winds over water were within 55%-85% of the winds measured by the reconnaissance aircraft. The ratio V_B/V_A depended strongly on the low-level atmospheric stability as indicated by the buoy air-sea temperature.

Provost, C., V. Garcon, and S.L. Garzoli. Sea level variability in the Brazil and Malvinas Confluence region. Advances in Space Research, 9(7):7387-7392 (1990).

No abstract.

Pszenny, A.A.P., J.N. Galloway, R.S. Artz, and J.F. Boatman. Overview of the 1988 GCE/CASE/WATOX studies of biogeochemical cycles in the North Atlantic region. Global Biogeochemical Cycles, 4(2):121-131 (1990).

The 1988 Global Change Expedition/Coordinated Air-Sea Experiment/Western Atlantic Ocean Experiment (GCE/CASE/WATOX) was a multifaceted research program designed to study atmospheric and oceanic processes affecting the biogeochemical cycles of carbon, nitrogen, sulfur, and trace metals in the North Atlantic Ocean region. Field work included: (1) a 49-day research cruise aboard NOAA Ship Mt. Mitchell (Global Change Expedition) from Norfolk, Virginia, to Bermuda, Iceland, the Azores, and Barbados; (2) eight flights of the NOAA King Air research aircraft, four off the Virginia Capes and four near Bermuda (CASE/WATOX); and (3) a research cruise aboard the yacht Fleurtie near Bermuda (WATOX). Objectives of GCE/CASE/WATOX were: (1) to examine processes controlling the mesoscale distributions of productivity, chlorophyll, and phytoplankton growth rates in Atlantic surface waters; (2) to identify factors controlling the distribution of ozone in the North Atlantic marine boundary layer; and (3) to estimate the contributions of sources on surrounding continents to the biogeochemical cycles of sulfur, nitrogen, and trace metals over the North Atlantic region during the boreal summer season.

Pszenny, A.A.P., G.R. Harvey, C.J. Brown, R.F. Lang, W.C. Keene, J.N. Galloway, and J.T. Merrill. Measurements of dimethyl sulfide oxidation products in the summertime North Atlantic marine boundary layer. Global Biogeochemical Cycles, 4(4):367-379 (1990).

Chemical data derived from air and precipitation samples collected during the Global Change Expedition/Coordinated Air-Sea Experiment/Western Atlantic Ocean Experiment (GCE/CASE/WATOX) over the North Atlantic Ocean (NAO) are interpreted using simple box models. Estimated total sulfur (S) deposition fluxes from air masses with tropical oceanic, African, clean North American, and polluted North American origins are 4.4, 16, 33, and 70 mol^-2 day^-1, respectively, with associated uncertainties of at least factors of 2 to 3. Crude estimates of the fractions of deposition attributable to marine biogenic versus anthropogenic S sources suggest that the latter may be enhancing the natural NAO atmospheric S cycle by a factor of 0.5 to 0.8. Combination with similar estimates for the North Pacific region (Savoie and Prospero, 1989) yields an overall, area-weighted enhancement factor of approximately 0.3 for northern hemisphere ocean areas, consistent with estimates by Wigley (1989) based on climate modeling studies.

Rona, P.A., R.P. Denlinger, M.R. Fisk, K.J. Howard, G.L.Taghon, K.D. Klitgord, J.S. McClain, G.R. McMurray, and J.C. Wiltshire (Federal/State Gorda Ridge Technical Task Force Working Group B). Major off-axis hydrothermal activity on the northern Gorda Ridge. Geology, 18(6):493-506 (1990).

The first hydrothermal field on the northern Gorda Ridge, the Sea Cliff hydrothermal field, was discovered and geologic controls of hydrothermal activity in the rift valley were investigated on a dive series using the DSSV Sea Cliff. The Sea Cliff hydrothermal field was discovered where predicted at the intersection of axis-oblique and axis-parallel faults at the south end of a linear ridge at mid-depth (2,700 m) on the east wall. Preliminary mapping and sampling of the field reveal: a setting nested on nearly sediment-free fault blocks 300 m above the rift valley floor 2.6 km from the axis; a spectrum of venting types from seeps to black smokers; high conductive heat flow estimated to be equivalent to the convective flux of multiple black smokers through areas of the seafloor sealed by a caprock of clastic breccia primarily derived from basalt with siliceous cement and barite pore fillings; and a vent biota with Juan de Fuca Ridge affinities; These findings demonstrate the importance of off-axis hydrothermal activity and the role of the intersection of tectonic lineations in controlling hydrothermal sites at seafloor spreading centers.

Rosenthal, S.L. A history of NOAA's Hurricane Research Division, including interactions with Florida State University's Department of Meteorology. Proceedings, 40th Anniversary Celebration, Department of Meteorology, Florida State University, Tallahassee, FL, November 30-December 1, 1989. Florida State University, Tallahassee, 42-47 (1990).

No abstract.

Rosenthal, S.L. Summary of the special sessions on Hurricane Hugo. 70th Annual Meeting of the American Meteorological Society, Anaheim CA, February 4-9, 1990. Bulletin of the American Meteorological Society, 71(9):1339-1342 (1990).

No abstract.

Shapiro, L.J., and K.V. Ooyama. Barotropic vortex evolution on a beta plane. Journal of the Atmospheric Sciences, 47(2):170-187 (1990).

A barotropic, primitive equation (shallow water) model is used on the beta plane to investigate the influence of divergence, total relative angular momentum (RAM), and advective nonlinearities on the evolution of a hurricane-like vortex. The multinested numerical model is based on the spectral application of a finite element representation. The undisturbed fluid depth is taken to be 1 km. Scaling of the vorticity equation, in conjunction with a Bessel function spectral decomposition, indicates that divergence should have a very small effect on the hurricane motion. Simulations with an initially symmetric cyclonic vortex in a resting environment confirm this analysis, and contradict previous published studies on the effect of divergence in a barotropic model. During a 120 h simulation, the cyclonic vortex develops asymmetries that have an influence far from the initial circulation. The total RAM within a large circle centered on the vortex decreases with time, and then oscillates about zero. For circles with radii <1000 km, the total RAM approaches, but does not reach, zero. An angular momentum budget indicates that the horizontal angular momentum flux tends to counteract the net Coriolis torque on the vortex. If the total RAM of the initial symmetric vortex is zero, the weak far-field asymmetries are essentially eliminated. The motion of the vortex is not, however, related to the RAM in any simple way. Within a few days the near-vortex asymmetries reach a near-steady state. The asymmetric absolute vorticity (AAV) is nearly uniform within ~350 km of the vortex center. The homogenization of AAV, which occurs within the closed vortex gyre, is likely due to shearing by the symmetric wind, combined with removal of energy at the smallest scales. The homogenization effectively neutralizes the planetary beta effect, as well as the vorticity associated with an environmental wind.

Thacker, W.C. Large least-squares problems and the need for automating the generation of adjoint codes. In Lectures in Applied Mathematics, Volume 26: Computational Solution of Nonlinear Systems of Equations, E.L. Allgower and K. Georg (eds). American Mathematical Society, Providence, Rhode Island, 645-677 (1990).

Some important least-squares problems that arise in oceanography and meteorology are large because they are based on systems of partial-differential equations. The function to be minimized is defined with the aid of a computer code, so the equations stating that the gradient should vanish are not available explicitly. It is possible to construct a second code that evaluates the gradient for a computational effort approximately equal to that of evaluating the function. Since the gradient code can be derived from the function code by following a well-defined set of rules, it should be possible to construct a compiler-like utility to do this task automatically. Such a compiler should find wide applicability, not only within oceanography and meteorology, but for optimization problems in general, as well as for solving systems of nonlinear equations and for checking the sensitivity of outputs of complicated codes to their inputs.

Thacker, W.C., and G. Holloway. Inverse problems and the principal of maximum entropy. Proceedings, International Symposium on Assimilation of Observations in Meteorology and Oceanography, Clermont-Ferrand, France, July 9-13, 1990. World Meteorological Organization, 6-11 (1990).

The principle of maximum entropy is discussed as a means of systematically estimating prior probabilities in solving a characteristic feature of oceanographic problems involving paucity of data. The principle is a refined version of Bernoulli's principle of insufficient reason for assigning Bayesian probabilities to possible outcomes in the light of available information. The information needed to constrain the entropy maximum corresponds to the experimental conditions necessary for the thermodynamic measurements to be repeated so that they take the form of expected values of macroscopic thermodynamic variables. A study (Holloway, 1986) is reviewed in detail. The study involves the application of statistical dynamical methods to geophysical fluid mechanics, by using the principle of maximum entropy probability distribution as a useful means prior to closing the inversion problem.

Tziperman, E., and W.C. Thacker. The adjoint method applied to an oceanic GCM: Model and simulations. Proceedings, International Symposium on Assimilation of Observations in Meteorology and Oceanography, Clermont-Ferrand, France, July 9-13, 1990. World Meteorological Organization, 62-64 (1990).

The application of the adjoint method, which is an optimization procedure, is examined to study the general circulation by using a numerical oceanic general circulation model and hydrographic data. The simplified GCM is based on the GFDL PE model of Bryan et al., except that its diagnostic momentum equations are simplified in contrast to the nonlinear prognostic momentum equations. The advection diffusion equation model for temperature and salinity is hydrostatic and mass conserving; and temperature, salinity, pressure, and density are related by an equation of state. The simplified momentum equations are the planetary geostrophic equations appropriate for modeling the large-scale general circulation of the ocean. In order to find the temperature, salinity, wind forcing, and surface fluxes of heat and fresh water which fit best the available hydrographic data and which are also as close as possible to a steady-state solution of the GCM, a cost function is defined which measures the success of the fit such that its value is a minimum when the optimization is completed. The simulations presented indicate that the adjoint method can be applied successfully to complex oceanic GCMs.

Wilburn, A.M., E. Johns, and M.H. Bushnell. Current velocity and hydrographic observations in the southwestern North Atlantic Ocean: Subtropical Atlantic Climate Study (STACS), 1989. NOAA Data Report, ERL AOML-18 (PB91-115535), 100 pp. (1990).

The primary objectives of the STACS program are to increase our understanding of the dynamics of the North Atlantic circulation and the role of ocean circulation in global climate, to develop the capability to monitor the climatically important processes, and to provide data needed in the development of the coupled ocean-atmosphere general circulation models to be used for global climate prediction. In particular, the mechanisms by which the ocean transports heat to balance the net radiation deficit at northerly latitudes are being studied. The initial objectives of STACS were directed at the Florida Current, a flow which makes significant contribution to heat flux. After an intensive two-year observing program, we have the capability to monitor Florida Current transport without extensive ship-board observations. Data from STACS cruises conducted on the NOAA Ships Albatross 4 and Malcolm Baldrige during two cruises, February and August 1989, are contained in the report.

Willis, P.T., and A.J. Heymsfield. Microphysical trajectories in tropical cyclones. Preprints, Conference on Cloud Physics, San Francisco, CA, July 23-27, 1990. American Meteorological Society, Boston, 666-671 (1990).

No abstract.

Willoughby, H.E. Gradient balance in tropical cyclones. Journal of the Atmospheric Sciences, 47(2):265-274 (1990).

Analysis of a large inventory of in-situ observations from research aircraft shows that the gradient wind approximates the axisymmetric swirling flow in the free atmosphere within 150 km of the centers of Atlantic hurricanes and tropical storms. In the middle and lower troposphere, the rms difference between azimuthal mean swirling and gradient winds is typically <1.5 m s^-1 with zero bias. This balance prevails only for the azimuthal mean, not locally, nor is balance to be expected in either the surface friction layer or the upper tropospheric outflow layer, where the radial flow is comparable with the swirling flow. It is theoretically possible that axisymmetric supergradient flow may occur in response to rapid radial acceleration where the radial flow slows in the friction layer beneath the eyewall or where it converges into intense diabatically-forced updrafts. Nevertheless, the observations in the free lower and midtroposphere show that systematic departures of the azimuthal mean vortex from balance are too small to measure.

Willoughby, H.E. Linear normal modes of a moving, shallow-water barotropic vortex. Journal of the Atmospheric Sciences, 47(17):2141-2148 (1990).

Calculations with a linear semispectral model of a moving tropical-cyclone-like barotropic vortex (Willoughby, 1988) show that a vortex with cyclonic circulation throughout exhibits unphysically fast poleward motion on a beta plane, but a vortex with enough anticyclonic circulation at its periphery to make the total relative angular momentum (L_R) small moves slowly. The high poleward speed arises because the vortex has a linear normal mode at zero frequency, where the beta effect forces asymmetric perturbations. Advection of planetary vorticity by the axisymmetric circulation forces this normal mode at a rate proportional to L_R. Because the governing equations are third-order in time, as many as three linear normal modes are possible. A completely cyclonic vortex has three repeated stable normal modes at zero frequency, whereas one with small L_R has a single stable mode at zero frequency and a conjugate pair of barotropically unstable modes. The frequency of the unstable modes lies at the most anticyclonic rotation frequency of the axisymmetric circulation, and the growth rate is slow; the e-folding time is typically 75 days. If the fluid is made very shallow, the stable normal mode moves away from zero frequency. In this situation, the beta effect fails to force the resonance, and the vortex propagates westward much as a planetary Rossby wave does. In this model, meridional motion of vortices with L_R = 0 always acts to adjust L_R toward zero through conservation of absolute angular momentum. Since the asymmetric perturbations are Rossby waves that propagate upon the radial gradient of mean relative vorticity, the mode at zero frequency experiences critical--radius absorption where the mean swirling wind is zero--at the boundary between cyclonic and anticyclonic mean circulation and at the edge of the vortex. Regardless of the sign of L_R, the wave momentum convergence is concentrated at these critical radii and weakens the circulation while expanding it spatially. When L_R = 0, waves emanating from the cyclonic and anticyclonic circulations interfere destructively, so that the vortex radiates no angular momentum to its environment.

Willoughby, H.E. Temporal changes of the primary circulation in tropical cyclones. Journal of the Atmospheric Sciences, 47(2):242-264 (1990).

More than 900 radial profiles of in-situ aircraft observations collected in 19 Atlantic hurricanes and tropical storms over 13 years confirm that the usual mechanism of tropical cyclone intensification involves contracting maxima of the axisymmetric swirling wind. Radar shows that annuli of convective echoes accompany the wind maxima. These features, called convective rings, exist and move inward because latent heat released in the rings leads to descent, adiabatic warming, and rapid isobaric height falls in the area they enclose. The radial change in rate of isobaric height fall is concentrated at the inner edge of the wind maximum, causing the gradient wind to increase there and the maximum to contract. Vigorous convection organized in rings invariably causes well-defined, inward-moving wind maxima, but when convection is weak, the rings are also weak or even absent. In this case, the swirling wind may be nearly constant with radius and change slowly in time. Hurricanes that have a single, vigorous, axisymmetric ring strengthen rapidly. Although a series of minor convective rings may support steady strengthening, development is more generally episodic. When asymmetric convection erupts near the center of tropical storms or weak hurricanes, it may cause intensification to falter and the cyclone tracks to become irregular. In intense hurricanes, outer convective rings may form around the pre-existent eyewalls, contract, and strangle the original eyewalls, halting intensification or causing weakening.

Wooldridge, A.L., S.E. Haggerty, P.A. Rona, and C.G.A. Harrison. Magnetic properties and opaque mineralogy of rocks from selected seafloor hydrothermal sites at oceanic ridges. Journal of Geophysical Research, 95(B8):12,351-12,374 (1990).

Magnetic properties (natural remanent magnetization [NRM], susceptibility [chi], Curie point temperature [T_c], saturation isothermal remanent magnetization [IRMs], and Koenigsberger ratio [Q]) and opaque mineralogy were determined for basalts, diabases, gabbros, peridotites, and serpentinites collected by dredging and submersible from the rift valley at five hydrothermal sites (15°N, 17°N, 23°N (the Snake Pit hydrothermal field), 26°N (the TAG hydrothermal field) on the Mid-Atlantic Ridge, and 42°N (the Sea Cliff hydrothermal field) on the northern Gorda Ridge). The magnetomineralogy is interpreted in terms of deuteric hydrothermal metasomatic and ambient seawater alteration. Evidence for unequivocal magnetic mineral modification by hydrothermal action is present only in a small percentage of extrusive basalts but is pervasive in diabases, gabbros, and ultramafic rocks. This lithologic distribution suggests a progressive increase in alteration intensity with depth in the oceanic crust and upper mantle from minor low-temperature alteration in young surface basalts to more pervasive high-temperature alteration in diabases, gabbros, and peridotites. The studies reveal distinct correlations between magnetization intensity, thermomagnetic behavior, and magnetic mineralogy, grain size, style, and intensity of alteration and rock type. Basalts have the highest NRM intensities and the lowest Curie points (105°-294°C); basalts with NRM/IRMs ratios less than 10^-2 may have been remagnetized and have NRM intensities and Q values much lower (one-third and one-half, respectively) than basalts with NRM/IRMs ratios of 10^-2 or magnetization (Q<1) occurs in metabasalts and the other rock types. Layer 2A basalts are the source of median valley magnetic anomalies. The magnetic source may shift from the surface to deeper horizons with progressive seafloor aging and enhanced deuteric oxidation in layer 2B dikes and layer 3 gabbros and the formation of magnetite in serpentinized peridotites. This shift is influenced by fluctuations in the Curie isotherm related to the duration of active magma chambers and convective hydrothermal cells. The magnetic and mineralogic properties of oceanic rocks determined show the effects of a wide range of alteration processes that are variously related to depth in oceanic lithosphere, magmatic cooling history, and hydrothermal circulation. **1989**

Bitterman, D.S., and D.V. Hansen. Direct measurements of current shear in the tropical Pacific Ocean and its effect on drift buoy performance. Journal of Atmospheric and Oceanic Technology, 6(2):274-279 (1989).

Measurements of ocean surface currents derived from drift buoy trajectories are subject to errors caused by slippage of the buoy relative to the surrounding water. This slippage error is caused by a number of forces acting on the buoy and drogue element, one of which is the current shear in the water. Idealized model calculations are used to exemplify some effects of vertical current shear on drogues, and on the performance of drogued buoy systems in current shear. It is shown that shear enhances the performance of drogues, and that long drogues should perform better than short drogues in shear, but shear also can induce slippage by adding drag force to the buoy hull. To establish environmental design parameters, average and rms current shear values between 9.7 m and 22.5 m depth were computed from Doppler acoustic current profiler measurements from the tropical Pacific Ocean. Largest values of shear (~0.25 s^-1 rms) were found near the equator in the eastern Pacific as expected. Elsewhere, the shear was generally less than 0.02 s^-1, mostly less than 0.01 s^-1. Average values of shear were generally less than 0.007 s^-1.

Black, M.L. Signal loss of WSR-57 radars as a function of range in tropical cyclones. Preprints, 24th Conference on Radar Meteorology, Tallahassee, FL, March 27-31, 1989. American Meteorological Society, Boston, 514-517 (1989).

No abstract.

Black, M.L., and F.D. Marks. Concentric eyewalls in Hurricane Gilbert (1988). Preprints, 18th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, May 16-19, 1989. American Meteorological Society, Boston, 224-225 (1989).

No abstract.

Black, P.G., L.K. Shay, R.L. Elsberry, and J.D. Hawkins. Response of the Gulf of Mexico to Hurricane Gilbert. Preprints, 18th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, May 16-19, 1989. American Meteorological Society, Boston, 226-227 (1989).

No abstract.

Brier, G.W., and K. Hanson. A nonparametric significance test of the solar-effect analysis of Labitzke and van Loon. Journal of Climate, 2(11):1417-1420 (1989).

No abstract.

Broecker, W.S., and T.-H. Peng. The cause of the glacial to interglacial CO₂ change: A polar alkalinity hypothesis. Global Biogeochemical Cycles, 3(3):215-239 (1989).

In an attempt to create a scenario for the cause of the glacial to interglacial CO₂ change recorded in air trapped in polar ice, we call on an increase in the alkalinity of polar surface waters. In this way we circumvent a major deficiency of the polar nutrient scenarios of Sarmiento and Toggweiler (1984), Siegenthaler and Wenk (1984), and Knox and McElroy (1984). Namely, our scenario does not require a drop in the nutrient content of polar surface waters in conformity with the demonstration by Boyle (1988a,b) that the cadmium content of planktonic foraminifera from polar regions did not decrease from late glacial to Holocene time. The rise in alkalinity required by our model is a natural consequence of the demise, during glacial time, of North Atlantic Deep Water as a major force in ocean circulation and of the nutrient maximum deepening of Boyle (1988b). Rather than being original, our hypothesis builds on the concept basic to the polar nutrient hypotheses, namely that the CO₂ partial pressure in polar waters controls that for both the atmosphere and warm surface ocean. It also requires the alkalinity increase in surface waters produced by Boyle's nutrient deepening.

Burpee, R.W. A summer day without significant rainfall in south Florida. Monthly Weather Review, 117(3):680-687 (1989).

Precipitating cumulus clouds occur regularly in the afternoon over the south Florida peninsula during summer months. A day without significant rainfall or radar echoes is rare. This paper discusses one such day, 23 July 1987, during which a dry, stable airmass covered the Florida peninsula. Nonprecipitating shallow cumulus formed in a few areas, but there were not any deep, precipitating cumulus clouds over land. The thermodynamic characteristics of the airmass are described and the synoptic-scale patterns that produced the airmass are presented.

Burpee, R.W. Gordon E. Dunn: Preeminant forecaster of midlatitude storms and tropical cyclones. Weather and Forecasting, 4(4):573-584 (1989).

No abstract.

Burpee, R.W., and M.L. Black. Temporal and spatial variations near the centers of two tropical cyclones. Monthly Weather Review, 117(10):2204-2218 (1989).

The Hurricane Research Division collected radar reflectivity data with a portable recorder attached to National Weather Service (NWS) WSR-57 radar as Hurricanes Alicia of 1983 and Elena of 1985 approached the coastline of the United States. The reflectivity data were used to estimate rain rates for the eyewall region, including the rain-free eye, and the rainbands in the annular area outside the eyewall, but within 75 km of the center of the eye. The rain rates include reflectivity corrections that were based upon the variation of average returned power with range in four hurricanes. This study examines the temporal and spatial variations of rain rates in the cores of Hurricanes Alicia and Elena. In Alicia, variations of area-averaged rain rate (R) in the eyewall region were caused by the growth and decay of mesoscale convective areas. In Elena, the life cycles of individual convective cells also accounted for large changes in the eyewall R. In both hurricanes, the time series of R in the rainband region was less variable than the eyewall R, because the rainband region was larger than the eyewall and contained a smaller percentage of convection. The distribution of precipitation in the eyewall and rainband regions was asymmetric. For several hours early in the observing period, the maximum rain rates in the eyewall and rainband regions of Alicia occurred in the left-front quadrant relative to the storm motion. Then, the heaviest rain in the eyewall region shifted to the right-front quadrant and that in the rainband region moved to the right of the storm track. In Elena, the maximum rain rates in the eyewall and rainband regions remained in the right-front quadrant throughout the computational period. About 55% of the precipitation in Elena's eyewall region occurred in the right-front quadrant.

Burpee, R.W., M.L. Black, and F.D. Marks. Vertical motions measured by airborne Doppler radar in the core of Hurricane Elena. Preprints, 18th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, May 16-19, 1989. American Meteorological Society, Boston, 69-70 (1989).

No abstract.

Carbone, R.E., and F.D. Marks. Velocity track display (VTD): A real-time application for airborne Doppler radar data in hurricanes. Preprints, 18th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, May 16-19, 1989. American Meteorological Society, Boston, 11-12 (1989).

No abstract.

Carder, K.L., R.G. Steward, G.R. Harvey, and P.B. Ortner. Marine humic and fulvic acids: Their effects on remote sensing of ocean chlorophyll. Limnology and Oceanography, 34(1):68-81 (1989).

Marine humic and fulvic acids were concentrated from about 1,400 liters of seawater from the Gulf of Mexico, and specific absorption coefficients were measured for each from 240 to 675 nmi. Spectral absorption coefficients were then calculated for Gulf of Mexico stations where earlier data on humic and fulvic acid concentrations were available. Marine humic and fulvic acid values have low molecular weights consistent with extrapolations from soil-derived curves of their specific absorption coefficients versus molecular weight. Marine fulvic and humic acids appear to account for most, if not all, water color or Gelbstoff in the offshore regions of the Gulf of Mexico. Based on a remote-sensing reflectance model, it appears that the increase in the Gelbstoff:chlorophyll ratio for waters adjacent to and downstream from regions of high primary productivity accounts for much of the deviation found for such waters from the global chlorophyll algorithm of the Coastal Zone Color Scanner.

DeMaria, M. A nested spectral model for hurricane track forecasting. Preprints, 18th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, May 16-19, 1989. American Meteorological Society, Boston, 206-207 (1989).

No abstract.

DeMaria, M., J.M. Davis, and D.M. Wojtak. Observations of mesoscale wave disturbances during the Genesis of Atlantic Lows Experiment. Monthly Weather Review, 117(4):826-842 (1989).

The Portable Automated Mesonet (PAM) data obtained during the Genesis of Atlantic Lows Fxperiment (GALE) are used to document mesoscale wave activity during the 3-day period from 4 to 6 February 1986. From the surface pressure analyses, four cases of wave activity are identified with wavelengths of 200-400 km, phase speeds of 20-40 m s^-1 and trough-to-crest pressure amplitudes of 0.5-3.5 mb. Precipitation was associated with the waves in two of the four cases. Detailed analyses of the horizontal structure show that the waves do not have the pressure-wind relationship expected from linear gravity wave theory. The wind vectors are oriented from high to low pressure with a maximum amplitude between the high and low pressure areas. Low-level inversions were present in three of the four cases. In the raw without a low-level inversion, the amplitude rapidly decreased as the wave moved towards the east. In the case which lasted for the longest time period (at least 8 h) and had the largest pressure amplitude, the sounding bad a critical level (where the wind speed equated the wave speed) and a level where the Richardson number was less than 0.25. Vertical velocities as large as 30 cm s^-1 were observed and them was some evidence that the wave was vertically tiled towards its direction of motion. Complex principal component analysis (CPCA) is applied to the surface pressure data to determine the applicability of this technique to the study of mesoscale waves. It is shown that CPCA could be used to generalize the results of this study to the entire 60-day period of GALE.

Dodge, P.P. The precipitation structure of Hurricane Elena. Preprints, 24th Conference on Radar Meteorology, Tallahassee, FL, March 27-31, 1989. American Meteorological Society, Boston, 522-524 (1989).

No abstract.

Enfield, D.B. El Niño, past and present. Reviews of Geophysics, 27(1):159-187 (1989).

El Niño events--anomalous warmings of the tropical Pacific with associated climatic and economic impacts around the globe--have occurred at several year intervals since before written records began with the logs of Francisco Pizarro in 1525. In this review, the history of El Niño research is traced from its beginnings through the key innovations of Bjerknes and Wyrtki to the unusual 1982-1983 event. Research is then reviewed, with detailed discussions of the key processes: instability growth and vacillation between climate states. Throughout the paper there are adjunct discussions of extraregional teleconnections, ecological impacts, and research on El Niño in the ancient record. The final section discusses the present paradigm for vacillations between El Niño and non-El Niño states and speculates on the possible chaotic nature of El Niño. El Niño and its atmospheric counterpart, the Southern Oscillation, appear to occur as an internal cycle of positive and negative feedbacks within the coupled ocean-atmosphere climate system of the tropical Pacific, although hypotheses based on external forcing also exist. All events are preceded by westerly wind anomalies on the equator near the date line. Baroclinic equatorial Kelvin waves are generated, propagating eastward toward South America where they depress the thermocline and raise sea level, while the deep, upper ocean reservoir of warm water in the western Pacific is depleted. Sea surface temperature (SST) anomalies in the cool eastern Pacific occur primarily because the normal source of cold water is depressed below the reach of mixing and upwelling processes. In the central equatorial Pacific, eastward advection by anomalous zonal flows is the principal mechanism. Nonlinear heat transfer to the lower atmosphere creates a positive ocean-atmosphere feedback resulting in the unstable growth of anomalies along the equator. Much of the present research aims at determining how the ocean-atmosphere system vacillates between the El Niño and non-El Niño states. Coupled models suggest that a longer time scale, negative-feedback process produces the transitions: at the apex of an El Niño development an anomalous atmospheric convection above the areas of reduced upper layer thickness in the off-equatorial ocean, which slowly propagate westward to the western boundary as Rossby waves and back to the central equatorial Pacific as upwelling Kelvin waves, re-establishing the normal cooling process. A similar negative feedback of opposite sign completes the second half of an oscillation, returning again to the El Niño state. However, the notion that El Niño/Southern Oscillation variability results only from an internal feedback process is still highly contentious and a number of external forcing mechanisms have been proposed.

Franklin, J.L. Objective analyses of Omega dropwindsonde data from Hurricane Josephine (1984). Preprints, 18th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, May 16-19, 1989. American Meteorological Society, Boston, 204-205 (1989).

No abstract.

Franklin, J.L., C.S. Velden, C.M. Hayden, and J. Kaplan. A comparison of VAS and ODW data around a subtropical cold low. Preprints, 4th Conference on Satellite Meteorology, San Diego, CA, May 16-19, 1989. American Meteorological Society, Boston, 141-144 (1989).

No abstract.

Frazel, D.W., G.A. Berberian, and G.L. Hitchcock. Global Change Expedition: Nutrient, chlorophyll-a, and primary productivity data, NOAA Ship Mt. Mitchell, July 14-September 6, 1988. NOAA Data Report, ERL AOML-15 (PB90-220336), 66 pp. (1989).

During the period of 14 July-6 September 1988, a multifaceted oceanographic research cruise called the Global Change Expedition was made on the NOAA Ship Mt. Mitchell in the North Atlantic Ocean. The objective of the cruise was to study the atmospheric and oceanic processes affecting the biogeochemical cycles of carbon, nitrogen, sulfur, and trace metals. Emphasis was made on compounds of these elements that would influence the radiation balance of the earth and, hence, of global climate. Measurements from hydrocasts for nutrients, phytoplankton biomass, and productivity were made on a daily basis during the period. The report represents the biological and chemical (nutrient) data from the cruise.

Gamache, J.F. Retrieval of thermodynamic and microphysical variables from airborne Doppler observations in Hurricane Norbert (1984). Preprints, 24th Conference on Radar Meteorology, Tallahassee, FL, March 27-31, 1989. American Meteorological Society, Boston, 525-528 (1989).

No abstract.

Gamache, J.F. The eyewall water budget of Hurricane Norbert (1984) as determined from airborne Doppler radar. Preprints, 18th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, May 16-19, 1989. American Meteorological Society, Boston, 73-74 (1989).

No abstract.

Garzoli, S.L., and Z. Garraffo. Transports, frontal motions, and eddies at the Brazil-Malvinas Currents Confluence. Deep-Sea Research, 36(5A):681-703 (1989).

Three inverted echo sounders were deployed to study the dynamics of the western South Atlantic Brazil-Malvinas Confluence region. Using a simple model, the location of the thermal front is obtained from the time series of the depth of the thermocline. Results show that the main motion of the front is an east-west displacement for distances of about 100 km; the observed period occurs with a periodicity of 12 months and is related to a variability in the latitude of maximum northward penetration of the Malvinas Current. Motions of the front, with a period of 1-2 months, are probably related to a north-south variation of the latitude of return of the Brazil Current.

Garzoli, S.L., and P.L. Richardson. Low-frequency meandering of the Atlantic North Equatorial Countercurrent. Journal of Geophysical Research-Oceans, 94(C2):2079-2090 (1989).

Four 19-month time series of indirect measurements of dynamic height were obtained in the tropical Atlantic along 28°W at 0°, 3°N, 6°N, and 9°N with three inverted echo sounders and one current meter mooring. The series were analyzed to study the time-latitude variability of the North Equatorial Countercurrent (NECC). The eastward flow associated with the NECC was present at 28°W from 3°N to 9°N during most of the observed period except in March-April 1983 and April-May 1984, periods that coincided with the onset of the wind at the equator. The amplitude of the NECC's annual cycle was maximum at 6°N and was larger in 1983 than in 1984. The analysis of the time-latitude variability of differences in dynamic height shows a long-period meridional shift of the NECC. The core of the current attains its northernmost location during August-September in both years and its southernmost location during March-April in 1983 and March in 1984. The location of the core is directly related to the position of the intertropical convergence zone. From the time series of dynamic height obtained from the indirect measurements, geostrophic velocities and transports were estimated and compared with direct observations of currents and values obtained from hydrographic casts.

Goni, G.J., F.D. Tappert, and M.G. Brown. Numerical experiments in the standard mapping. RSMAS Technical Report 89-005 (1989).

No abstract.

Hansen, D.V., and A. Herman. A seasonal isotherm depth climatology for the eastern tropical Pacific. NOAA Technical Report, ERL 434-AOML-33 (PB89-193577), 41 pp. (1989).

A seasonal climatology of the depths of the 10°C, 15°C, and 20°C isotherms in the eastern tropical Pacific is presented. The analyses used Kriging, which is a method for optimal interpolation of data fields. The data set consisted of 10,505 expendable bathythermograph (XBT) and conductivity-temperature-depth (CTD) stations collected during non-El Niño years. Results are presented on shaded contour maps with values overprinted at 2° intervals. The method of analysis also yields an estimate of the uncertainty of each interpolated point.

Hansen, D.V., and A. Herman. Evolution of isotherm depth anomalies in the eastern tropical Pacific Ocean during the El Niño event of 1982-1983. Journal of Geophysical Research, 94(C10):14,461-14,473 (1989).

Subsurface temperature data collected from research vessels, aircraft, and vessels of opportunity are used to describe the evolution of the major El Niño event in the tropical Pacific from September 1982 through September 1983. Optimum interpolation is used to create six analysis mas of the anomalous depths of the 20°C, 15°C, and 10°C isothermal surfaces. The regions analyzed is 20°N to 20°S and 140°W to the coast of the Americas. Each analysis is based on data accumulated over about a month, and the analysis periods are separated by about a month. The depths of the 20°C isotherm are used to compute zonal thermoclinic transports across 100°W of the North and South Equatorial Currents and the North Equatorial Countercurrent.

Hansen, D.V., and A. Herman. Temporal sampling requirements for surface drifting buoys in the tropical Pacific. Journal of Atmospheric and Oceanic Technology, 6(4):599-607 (1989).

Drifting buoy data from the eastern tropical Pacific Ocean are used to evaluate the degradation of sea surface temperature and current information incurred by reducing the number of transmissions from drifting buoys using the ARGOS system for position finding. Buoy locations are interpolated at uniform time intervals using an optimum interpolation method known as Kriging, which provides also an estimate of the rms position error. It is found that the published standard for surface current measurement for the TOGA Program (5 cm s^-1) can be met with transmissions on one day of three in the Southern Hemisphere. Due to stronger mesoscale variability in the Northern Hemisphere, the standard would be jeopardized by reducing transmissions even to one day of two. The standard for observation of sea surface temperature (0.1°C) can be met in either hemisphere with transmissions on one day of four. The Lagrangian decorrelation times for the Northern Hemisphere region of the eastern tropical Pacific are estimated as four days in the meridional direction, and 14 days in the zonal direction. It is recommended that transmissions be made on one day of three, and the time scale for the TOGA standard be revised accordingly.

Hanson, K., and G.A. Maul. Analysis of the historical meteorological record at Key West, Florida (1851-1986) for evidence of trace-gas induced climate change. In Implications of Climatic Changes in the Wider Caribbean Region. United Nations Environment Programme (UNEP), OCA/CAR WG.1/INF.3, 27-35 (1989).

Meteorological data for Key West, Florida have been examined for evidence of changes during recent decades that may be attributed to increasing trace gases in the atmosphere. The 136-year temperature record (1851-1986) gives evidence that a warming has occurred. However, there are questions of the reality of the warming, because of the mix of temperature observing conditions over the period of record. The 101-year precipitation record (1886-1986) gives evidence that no significant change in precipitation has occurred during the period of record. Future work on the reality of the apparent warming at Key West is suggested.

Hanson, K., G.W. Brier, and G.A. Maul. Evidence of significant nonrandom behavior in the recurrence of strong El Ni�os between 1525-1988. Geophysical Research Letters, 16(10):1181-1184 (1989).

The precise character of the quasiperiodic variation in the recurrence of El Ni�o events has been unclear. To gain insight into the nature of this apparent regularity, a 464-year record (1525-1988) of the initiation of "strong" El Ni�o events, derived from the chronology of Quinn et al. (1987), has been analyzed with a two-dimensional extension of the periodogram analysis method of Buys Ballot. The method is useful for detecting joint nonlinear interactions between variations at two specified periods. Results indicate joint nonrandom recurrence of strong El Ni�o events at periods of 6.75 and 14 years. From Monte Carlo tests, we estimate the statistical significance of this result to be at the 0.1% level. Alternating 95 year-long time-blocks, where 6.75-year and 14-year recurrence periods dominate, is apparent from the analysis. No specific mechanism is offered for the periodic forcing of strong El Ni�o events, but our observation of significant quasi-periodic behavior in the initiation of such events at the combined periods of 6.75 and 14 years may be a clue in efforts to understand and model natural ENSO recurrence.

Hanson, K., G.A. Maul, and T.R. Karl. Are atmospheric "greenhouse" effects apparent in the climatic record for the contiguous U.S. (1985-1987)? Geophysical Research Letters, 16(1):49-52 (1989).

The temperature and precipitation climate records for the United States have been examined. These records consist of area-averages across the contiguous United States and northern plains. They are based on as many as 6,000 stations. Time series of these data were tested for constancy of the mean using the Spearman rank test and two-phase regression. Test results indicate that overall trends are near zero. The only evidence for a long-term trend is in fall precipitation for the contiguous United States. This trend appears to result from a higher fall precipitation during the period 1970-1987 compared to the remainder of the period (1895-1969).

Hirsh, M.A., and H.A. Friedman. Creating an awareness of the hurricane problem in at-risk coastal communities of south Florida. Preprints, Second International Conference on School and Popular Meteorological and Oceanographic Education, Crystal City, Virginia, July 12-16, 1989. American Meteorological Society, Boston, 160-162 (1989).

No abstract.

Houde, E.D., P.B. Ortner, L. Lubbers, and S.R. Cummings. Test of a camera-net system to determine abundance and heterogeneity in anchovy egg distributions. Rapports et Proces-Verbaux des Reunions Conseil International pour l'Exploration de al Mer, 191:112-118 (1989).

A prototype, in-situ camera-net system was deployed in Chesapeake Bay to test its ability to estimate abundances and delineate fine-scale vertical and horizontal distributions of bay anchovy Anchoa mitchilli eggs and larvae. Hydrographic variables were measured synoptically by electronic sensors on the system. Comparison catch data were obtained by simultaneous deployment of a conventional plankton net. The camera subsampled 1.9% of the water that entered the system and photographed part of the catch at 2-m intervals along the tow. Densities of anchovy eggs, which averaged 99.0 m^-3 during six trial tows, were estimated at 1, 5, and 10 m depths. Anchovy larvae were uncommon (0.34 m^-3) and not sampled effectively. The system detected increasing egg abundances between the surface and 10 m depth and horizontal patchiness over 10-100 m distances. In the configuration used, the system has potential where mean egg or larval densities exceed ca. 5 m^-3. Its advantages are that it can (1) reduce the need to collect and sort plankton samples, (2) provide photographic data for image analysis, and (3) synoptically assess fine-scale distributions of ichthyoplankton, environmental variables, and co-occurring predators and prey.

Johns, E., D.R. Watts, and H.T. Rossby. A test of geostrophy in the Gulf Stream. Journal of Geophysical Research, 94(C3):3211-3222 (1989).

In July 1982 two detailed sections of density and absolute velocity were taken across the Gulf Stream northeast of Cape Hatteras to conduct an accurate test of geostrophy in a strong current. The sections, which were taken about four days apart, were each completed within 48 hours, using one ship to make closely spaced (12 km) conductivity-temperature-depth measurements to 2000 m, and a second ship to simultaneously take Pegasus absolute velocity profiles to the ocean bottom. The Gulf Stream path and curvature were also surveyed. The dynamically inferred velocity profiles were made absolute by matching their velocities to the Pegasus profiles at 2000 m. The geostrophic method (properly referenced) underestimated the observed velocities by 10-25 cm s^-1 in the core of the current above 500 m where speeds exceeded 150 cm s^-1. The difference is a factor of 2, larger than the sampling and measurement errors in corresponding parts of the current, estimated to be 5-10 cm s^-1, well within the uncertainties of the method. The transport above 2000 m is less sensitive to curvature effects; it agrees to within 3 Sv before and 1 Sv after correcting for curvature, or approximately 2% of the total 93 Sv transport. The deep velocity field below 1000 m had significant changes (10-20 cm s^-1) in structure, and even reversals, in the four days between the sections, with cross-stream scales of 50-100 km. This deep variability, attributed to topographic Rossby waves, introduces more than 10 Sv uncertainty in defining the total volume transport of the Gulf Stream.

Landsea, C.W., H.E. Willoughby, and J.M. Masters. Analysis of Hurricane Gilbert at its maximum intensity. Preprints, 18th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, May 16-19, 1989. American Meteorological Society, Boston, 222-223 (1989).

No abstract.

Leaman, K.D., E. Johns, and H.T. Rossby. The average distribution of volume transport and potential vorticity with temperature at three sections across the Gulf Stream. Journal of Physical Oceanography, 19(1):36-51 (1989).

Average cross sections of downstream velocity and temperature, obtained using PEGASUS current profilers at three locations along the Gulf Stream, have been partioned into 2.5°C temperature intervals to examine the distribution of transport increase versus temperature between the two southern sections (27° and 29°N) and off Cape Hatteras (73°W). Between 27° and 29°N the total transport of the Florida Current over the sections increased only by about 3 × 10⁶ m³ s^-1 (3 Sv) but the current broadens by about 50%. By Cape Hatteras, the transport has increased nearly three-fold to 93.7 Sv, of which two-thirds of the increase is contained in the 19.5°-17.0°C ("18°") layer and in water colder than the 7°C "sill" temperature found at 27°N. Cross-stream distributions of layer transport, potential vorticity, and thickness are estimated. At each section, the 10 × 10^-7 m^-1 s^-1 contour tends to be a boundary (independent of temperature) between the region of relatively uniform layer potential vorticity on the anticyclonic (offshore) side of the current and an area with high lateral potential vorticity gradients on the cyclonic (onshore) side. In the colder (<7°C) waters off Cape Hatteras, layer potential vorticity also tends to be uniform at ~5 × 10^-7 m^-1 s^-1. Layer potential vorticity in the 18° layer is quite uniform with minimum values ~3.5 × 10^-7 m^-1 s^-1 at 27° and 29°N and somewhat less off Cape Hatteras, which is close to where 18°C water is formed in the wintertime. At Cape Hatteras this same layer shows a peak in transport/unit width at the point where the layer begins to thin as one moves into the Gulf Stream core from the southeast. A simple model based on conservation of layer potential vorticity is proposed to describe this transport structure.

Lierhiemer, L.J., P.C. Fiedler, S.B. Reilly, R.L. Pitman, L.T. Ballance, G.G. Thomas, and D.W. Behringer. Report of ecosystem studies conducted during the 1988 eastern tropical Pacific dolphin survey on the research vessel David Starr Jordan. NOAA Technical Memorandum, NMFS-SWFC-131, 125 pp. (1989).

No abstract.

Lierhiemer, L.J., P.C. Fiedler, S.B. Reilly, R.L. Pitman, L.T. Ballance, and D.W. Behringer. Report of ecosystem studies conducted during the 1988 eastern tropical Pacific dolphin survey on the research vessel McArthur. NOAA Technical Memorandum, NMFS-SWFC-132, 121 pp. (1989).

No abstract.

Long, R.B., and W.C. Thacker. Data assimilation into a numerical equatorial ocean model, Part 1: The model and the assimilation algorithm. Dynamics of Atmospheres and Oceans, 13(3-4):379-412 (1989).

In the present paper, the first of two parts, we illustrate the application of Thacker and Long's approach by constructing a data-assimilating version of an equatorial ocean model incorporating the adjoint method. The model is subsequently run for five years to near-steady-state, and exhibits many of the features known to be characteristic of equatorial oceanic flows. Using the last 54 days of the run as a control, a set of simulated sea-level and subsurface-density observations are collected, then successfully assimilated to demonstrate that the procedure can recover the control run, given a generous amount of data. In part II we conduct a sequence of numerical experiments to explore the ability of more limited sets of observations to fix the state of the modeled ocean; in the process, we examine the potential value of sea-level data obtained via satellite altimetry.

Long, R.B., and W.C. Thacker. Data assimilation into a numerical equatorial ocean model, Part 2: Assimilation experiments. Dynamics of Atmospheres and Oceans, 13(3-4):413-439 (1989).

A sequence of numerical experiments is conducted using a linear, semi-spectral equatorial ocean model and an advanced data assimilation scheme. The numerical model is based on decomposition of the oceanic fields into Kelvin and Rossby waves belonging to the baroclinic modes of a stratified equatorial ocean. The assimilation procedure finds that solution to the model equations that best fits, in the generalized least-squares sense, all observations made within some specified space-time interval. All experiments are of the "identical twin" type; synthetic data are generated by sampling the observable fields produced by a control run of the model, then the data are assimilated using the same model. The sequence of numerical experiments serves two purposes: to demonstrate the performance of the assimilation procedure in the context of a fully three-dimensional, time-varying equatorial ocean model, and to examine the utility of specified data sets, and in particular, observations of sea level, in estimating the state of the equatorial ocean. The results indicate that the assimilation procedure works very well when sufficient data are provided. However, sea level data alone are not sufficient and must be supplemented with subsurface observations if more than a few baroclinic modes are allowed in the model ocean. The required amount of supplementary subsurface data (in the form of density profiles in these experiments) can be reduced by imposing smoothness constraints on the recovered model solution.

Lord, S.J. Vorticity advection from nested analyses of the hurricane environment. Preprints, 18th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, May 16-19, 1989. American Meteorological Society, Boston, 202-203 (1989).

No abstract.

Lyons, W.A., M.G. Venne, P.G. Black, and R.C. Gentry. Hurricane lightning: A new diagnostic tool for tropical storm forecasting? Preprints, 18th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, May 16-19, 1989. American Meteorological Society, Boston, 113-114 (1989).

No abstract.

Marks, F.D. Kinematic structure of the inner core of hurricanes as viewed by airborne Doppler radar. Proceedings, Third Interagency Airborne Geosciences Workshop, La Jolla, CA, February 21-24, 1989. American Meteorological Society, Boston, IV79-IV81 (1989).

No abstract.

Marks, F.D. Three-dimensional structure of the eyewall of Hurricane Emily (1987) as determined from an airborne Doppler radar. Preprints, 18th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, May 16-19, 1989. American Meteorological Society, Boston, 71-72 (1989).

No abstract.

Marks, F.D., and S.J. Lord. Kinematic structure of Hurricane Gloria as viewed by airborne Doppler radar and Omega dropwindsondes. Preprints, 24th Conference on Radar Meteorology, Tallahassee, FL, March 27-31, 1989. American Meteorological Society, Boston, 529-532 (1989).

No abstract.

Maul, G.A. Climate change and sea level rise in the Caribbean region. The Siren, 39:15-17 (1989).

No abstract.

Maul, G.A. Implications of climatic changes in the wider Caribbean region: An overview. In Coping with Climate Change, J.C. Topping (ed.). Climate Institute, Washington, D.C., 432-458 (1989).

No abstract.

Maul, G.A., and N.J. Bravo. Fate of satellite-tracked buoys and drift cards off the southeastern Atlantic coast of the United States. Florida Scientist, 52(3):154-170 (1989).

Twelve satellite-tracked drifting buoys were released, one each month between April 1984 and March 1985, at the 75 m isobath, 70 km southeast of Cape Canaveral, Florida. Starting in May 1984, 500 drift cards were also released at each buoy deployment from the same site (28°N, 80°W). In addition, satellite-tracked buoys from May 1979, September 1983, and February 1985, which drifted into or through the area, were studied for information about surface currents and particle trajectories. All 12 buoys from the 28°N/80°W launch site drifted north past Cape Canaveral (28.5°N); only the May 1984 buoy drifted into the coastal zone off Mayport, Florida (30.4°N), although several others showed a tendency to do so in that area. Every buoy deployed within 5 km of the western edge of the Gulf Stream was entrained into the current, and some as far as 25 km were also entrained. The September 1983 buoy, which was deployed slightly west of 28°N/80°W, and the February 1985 buoy, which was deployed in the Gulf of Mexico, both came ashore near St. Lucie Inlet, Florida (27.2°N), 140 km south of Cape Canaveral. Drift cards from May, September, October, and November 1984, and February 1985 were recovered west and north of 28°N/80°W. Forty percent of the cards recovered were from south of Cape Canaveral; Cocoa Beach, Florida (28.3°N), and Ponteverda Beach, Florida (30.2°N) reported most of the returns. For those months when drift cards were returned, buoy trajectories showed little correlation with drift card vectors. Drift cards established the possibility of materials coming ashore along the Florida Atlantic coast, both north and south of Cape Canaveral, particularly in the autumn.

Maul, G.A., and K. Hanson. Sea level variability in the Intra-American Sea with concentration on Key West as a regional example. In Implications of Climatic Changes in the Caribbean Region. United Nations Environment Programme (UNEP), OCA/CAR WG.1/INF.3, 89-101 (1989).

No abstract.

Maul, G.A., J.R. Proni, M.H. Bushnell, and J.L. Mitchell. Oceanic dynamic height anomaly from GEOSAT: A conceptual model for short collinear orbit segments. Marine Geodesy, 12:259-285 (1989).

A method is derived for extracting oceanic dynamic height anomaly from collinear (exact repeat mission) GEOSAT short (~1,000 km long) orbit segments. The procedure requires at least one year of simultaneous in-situ observations and involves: (1) computing with respect to the ellipsoid, a mean sea surface height (SSH) profile solely from altimetry; (2) linear least-squares removal of tilt and bias from individual SSH profiles with respect to the mean profile; (3) determining an independent mean dynamic height anomaly profile from hydrographic data along the orbit segment; (4) demeaning the tilt-and-bias removed individual SSH profiles and addition of the mean in-situ dynamic height anomaly; and (5) correcting for concurrently observed dynamic height anomaly at two or more suborbital points during satellite transit. Analysis of the concept suggests root sum squared errors of ±5 cm, which can be reduced by smoothing and longer term measurements along the same orbit segment. A one-year comparison between two orbit segments at an open ocean crossover point shows differences of ±2 cm, and comparison with six months of simultaneous in-situ data shows corrections of ±3 cm are required. Space-time plots of demeaned tilt-and-bias removed GEOSAT SSH profiles, compared with similarly processed NMC/CAC numerical circulation model calculations, show good agreement with variability in the South Equatorial Current/North Equatorial Countercurrent system in the eastern Pacific Ocean, and suggest that further development of the concept is warranted.

McCreary, J.P., H.S. Lee, and D.B. Enfield. The response of the coastal ocean to strong offshore winds: With application to circulation in the Gulfs of Tehuantepec and Papagayo. Journal of Marine Research, 47(1):81-109 (1989).

Two ocean models are used to investigate the response of the coastal ocean to strong offshore winds: a linear 1 1/2-layer model, and a non-linear 1 1/2-layer model that allows entrainment of cool water into the surface layer. The models are forced by wind stress fields similar in structure to the intense wintertime, mountain-pass jets (~20 dyne/cm²) that appear in the Gulfs of Tehuantepec and Papagayo for periods of three to ten days. Solutions are arranged in a hierarchy of increasing dynamical complexity in order to illustrate the important physical processes. They compare favorably with observations in several ways. Some properties of solutions are the following. While the wind strengthens, there is an ageostrophic current (not Ekman drift) that is directed offshore. This offshore drift forces coastal upwelling, thereby lowering the local sea level and sea surface temperature (SST). Although the drop in sea level at the coast can be large and rapid (of the order of 20 cm at the peak of a wind event), none of this signal propagates poleward as a coastally-trapped wave. While the wind weakens, the ageostrophic current is directed onshore, and consequently the coastal ocean readjusts toward its initial state. Throughout the wind event, cyclonic and anticyclonic gyres spin up offshore on either side of the jet axis due to Ekman pumping. Entrainment cools SST offshore on and to the right (looking onshore) of the jet axis, and virtually eliminates the cyclonic gyre. The advection terms intensify the anticyclonic gyre and give it a more circular shape. After a wind event, the anticyclonic gyre propagates westward due to beta. Its propagation speed is enhanced over that of a linear Rossby wave due to the nonlinear terms associated with the increased thickness at the center of the gyre and with the divergence of momentum flux.

Miller, K.L., and P.A. Rona. Bathymetric comparison of three mid-ocean ridge areas with slow-spreading characteristics. NOAA-National Undersea Research Program, Technical Report 89-3, 41 pp. (1989).

The Trans-Atlantic Geotraverse (TAG) and adjacent sections of the Mid-Atlantic Ridge (MAR), the French-American Mid-Ocean Undersea Study (FAMOUS) area of the MAR, and the northern and central Gorda Ridge all possess slow-spreading characteristics, although not all have slow-spreading rates (half-rate 2 cm/yr). Because spreading rate is not the only factor controlling mid-ocean ridge morphology, the three ridge sections were compared to determine what similarities and differences exist between them. Similarities and differences were observed in morphologic character, valley shape, and valley symmetry of these three areas. Two hydrothermal fields located within the study areas, the TAG hydrothermal field and the newly discovered Sea Cliff hydrothermal field, were also compared to determine if a particular geologic setting is common to both hydrothermal fields. This comparison considered placement of the hydrothermal fields along the ridge segment, rift valley morphology, shape, and valley symmetry.

Millero, F.J., J.P. Hershey, G. Johnson, and J.-Z. Zhang. The solubility of SO₂ and the dissociation of H₂SO₃ in NaCl solutions. Journal of Atmospheric Chemistry, 8:377-389 (1989).

The pK₁* and pK₂* of H₂SO₃ have been determined in NaCl solutions as a function of ionic strength (0.1 to 6 m) and temperature (5 and 25°C). The extrapolated values in water were found to be in good agreement with literature data. The experimental results have been used to determine the Pitzer interaction parameters for SO₂, HSO₃^-, and SO₃^2- in NaCl solutions. The resultant parameters for NaHSO₃ and Na₂SO₃ were found to be in reasonable agreement with the values for NaHSO₄ and Na₂SO₄. It thus seems reasonable to assume that the interactions of Mg²⁺ and Ca²⁺ with HSO₃^- and SO₃^2- can be estimated from the values with HSO₄^- and SO₄^2- until experimental values are available. Measurements of pK₁* and pK₂* in artificial seawater were found to be in good agreement with the calculated values using the derived Pitzer parameters. It is, thus, possible to make reasonable estimates of the activity coefficients HSO₃^- and SO₃^2- ions and pK₁* and pK₂* for the ionization of H₂SO₃ in marine aerosols.

Molinari, R.L. Subtropical Atlantic Climate Studies (STACS): An update. Oceanography, 2(2):32-35 (1989).

The subtropical Atlantic Climate Studies (STACS) of the National Oceanic and Atmospheric Administration (NOAA) is a multi-investigator, multi-institutional program directed at (1) increased understanding of the role of western boundary currents of the Atlantic Ocean in meridional oceanic heat flux, and (2) development of strategies to monitor important western boundary features. The initial emphasis of STACS was on the subtropics (Molinari, 1983; Molinari, 1986) where earlier studies suggested that oceanic heat flux in the Atlantic is a maximum (e.g., Bryan et al., 1975; Oort and Vonder Haar, 1976; Hastenrath, 1980). A two-year intensive observing period was conducted between 1982 and 1984 to study the role of the Florida Current in both the circulation of the subtropics and oceanic heat flux, as well as to devise sampling strategies for long-term monitoring of this western boundary current. Beginning in mid-1984, STACS operational efforts became focused on circulation features along the Antillean Archipelago and the eastern Caribbean Sea.

Ooyama, K.V. Thermodynamics in the primitive form for modeling the moist atmosphere. Preprints, 18th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, May 16-19, 1989. American Meteorological Society, Boston, 157-158 (1989).

No abstract.

Ortner, P.B., L.C. Hill, and S.R. Cummings. Zooplankton community structure and copepod species composition in the northern Gulf of Mexico. Continental Shelf Research, 9(4):387-402 (1989).

Zooplankton community structure and copepod species composition are analyzed in samples obtained during spring and winter from three areas of the northern Gulf of Mexico: near the Mississippi River outflow, off Cape San Blas, and in the central Gulf of Mexico. Samples from different regions were distinguishable in correspondence analysis of dominant species and/or functional groups. The near-surface communities of the Mississippi and central Gulf were particularly distinct while Cape San Blas was intermediate in both structure and specific character. Saltier waters directly beneath the Mississippi plume yielded samples similar to those from near-surface waters well offshore. At the same time near-surface waters off the Mississippi and off Cape San Blas to the west were distinguishable even during spring when the outflow from the Mississippi was at its annual peak. These differences are consistent with the discharge and flow patterns of the Mississippi River plume and the northern Gulf and with systematic differences in such parameters as temperature, salinity, and chlorophyll concentration. The implications of these observations upon the feeding environments of the larvae of commercially significant fish species are addressed since both zooplankton prey and larval predators appear to be particularly abundant in the Mississippi River plume environs.

Pazos, M.C., and J.P. Umaran-Barrueto. Drifting buoy data from the eastern equatorial Pacific for the period June 1, 1985 through June 30, 1987. NOAA Data Report, ERL AOML-16 (PB90-240011), 254 pp. (1989).

A test to compare the activity and performance of 60 satellite-tracked, free drifting buoys was put into operation in the eastern tropical Pacific Ocean during the June 1, 1985-June 30, 1987 period. Of the total number of buoys, 56 were designed and built at NOAA/AOML (Bitterman and Hansen, 1986), two were made by Technocean, and two others were FGGE design constructed by the Polar Research Laboratory, Inc. The details of their trajectories and histories are presented and discussed in this data report.

Peng, T.-H. Changes in ocean ventiliation rates over the last 7000 years based on ¹⁴C variations in the atmosphere and oceans. Radiocarbon, 31(3):481-492 (1989).

Changes in the ocean ventilation rate may be one of the causes for a net decrease of 100^o/_oo DELTA ¹⁴C in atmospheric CO₂ over the last 8000 years. Ocean ventilation rates of the past can be derived from the ¹⁴C record preserved in planktonic and benthic foraminifera in deep-sea sediments. Results of ¹⁴C dating using accelerator mass spectrometry on deep sea sediments from the South China Sea show that the age differences between planktonic (G sacculifer) and benthic foraminifera increase from 1350 yr ca 7000 yr ago to 1590 yr at present. An 11-box geochemical model of global ocean circulation was used for this study. Both tree-ring-determined atmospheric ¹⁴C values and foraminifera ¹⁴C age differences are used as constraints to place limits on patterns of changes in ocean ventilation rates and in atmospheric ¹⁴C production rates. Results indicate: (1) ¹⁴C production rates in the atmosphere may have decreased by as much as 30% between 7000 and 3000 yr ago, and may have increased again by ca 15% in the past 2000 yr; and (2) the global ocean ventilation rate may not have been at steady state over the last 7000 yr, but may have slowed by as much as 35%.

Peng, T.-H., W.M. Post, D.L. DeAngelis, V.H. Dale, and M.P. Farrell. Atmospheric carbon dioxide and the global carbon cycle. The key uncertainties. In Alternative Energy Sources VIII, Volume 2: Research and Development, T.N. Veziroglu (ed.). Hemisphere Pub. Corp., New York, 707-728 (1989).

No abstract.

Peterson, D.H., D.R. Cayan, J.F. Festa, F.H. Nichols, R.A. Walters, J. V. Slack, S.E. Hager, and L.E. Schemel. Climate variability in an estuary: Effects of riverflow on San Francisco Bay. In Aspects of Climate Variability in the Pacific and Western Americas, D.H. Peterson (ed.). American Geophysical Union, Geophysical Monograph 55, 419-442 (1989).

No abstract.

Piotrowicz, S.R., R.A. Rasmussen, K.J. Hanson, and C.J. Fischer. Ozone in the boundary layer of the equatorial Atlantic Ocean. Tellus B, 41(3):314-322 (1989).

Shipboard (~7) ozone and carbon monoxide measurements made in the equatorial Atlantic Ocean south of the inter-tropical convergence zone between 5°N and 10°S and 10°-30°W in August and September of 1986 exhibited variability in excess of a factor of 2. Ozone mixing ratios ranged from <25 to over 50 ppbv while carbon monoxide mixing ratios ranged from <50 to over 120 ppbv along the western edge of the equatorial Atlantic in spite of the fact that the prevailing surface winds were from the east to southeast at between 5 and 15 m/sec. Ozone and carbon monoxide mixing ratios were generally lower and exhibited less variability in the eastern tropical Atlantic where a lighter, south to southeasterly wind regime predominated. Isobaric trajectory analyses indicated that the high ozone and carbon monoxide mixing ratios appear to be related to long-range transport off of the African continent. Time series analysis of the ozone data indicates a diel cycle in ozone mixing ratios with a morning maximum and afternoon minimum.

Powell, M.D. Boundary-layer kinematic structure in outer hurricane rainbands. Preprints, 18th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, May 16-19, 1989. American Meteorological Society, Boston, 67-68 (1989).

No abstract.

Powell, M.D. Boundary-layer structure and dynamics in outer hurricane rainbands. Preprints, 24th Conference on Radar Meteorology, Tallahassee, FL, March 27-31, 1989. American Meteorological Society, Boston, 533-536 (1989).

No abstract.

Proni, J.R., W.P. Dammann, J.F. Craynock, and R. Fergen. Oceanic wastewater plume characteristics measured acoustically. Proceedings, Eighth International Ocean Disposal Symposium, Dubrovnik, Yugoslavia, October 9-13, 1989. Inter-University Center of Postgraduate Studies, 18-19 (1989).

The measurement of oceanic wastewater plume features is complex and the obtaining of samples of plume material is difficult. A study, called SEFLOE, has been conducted on wastewater outfalls off the coast of southeast Florida (USA). The wastewater plume field F(r,0,z,t) is considered to be comprised of a set of subfields f_i(r,0,z,t), i.e., F(r,0,z,t) = F(f_i, ..., f_i, ..., f_n); likewise, the oceanic water column field W(r,0,z,t), into which the wastewater plume is injected, is considered to be comprised of a set of subfields; i.e., W(r,0,z,t) = W(W₁, ..., w_i, ..., w_n). In this study, the feasibility of utilizing high-frequency acoustics to provide an estimator field I(r,0,z,t) for one or more of the wastewater plume subfields f_i(r,0,z,t) is examined. It is hypothesized that the water-column background corrected acoustical backscattered intensity I(r,0,z,t) where I(r,0,z,t) = <I_f(r,0,z,t)> - <I_w(r,0,z,t)> may be used to guide chemical/biological sampling and the physical structure of at least one wastewater plume subfield is revealed by the structure of I(r,0,z,t) (the brackets denote a measured quantity). Data from SEFLOE have indicated that the wastewater plume field is divided into regions of higher concentration, spatially separated by regions of lower concentration; we call these regions of higher concentration "boluses." When the water column is density stratified, a "peeling-off" effect of the outer portions of the rising wastewater plume is observed. The outer portions "peel-off" into a vertical series of subsurface plumes at different depths within the water column. The rate of dilution with range for a purely surficial plume which existed in January 1988 is compared within the rate of dilution with range of subsurface plume which existed in June of 1988. In the surface plume, a much slower dilution rate is observed for acoustical, dye and fecal streptococcal subfields, while a somewhat slower dilution rate was observed for the fecal coliform. In the subsurface plume, a much slower dilution rate is observed. In addition to dilution with range, mean value, standard deviation and the peak-to-mean values are presented as a function of range for a specific ship transect.

Pszenny, A.A.P., A.J. Castelle, and J.N. Galloway. A study of the sulfur cycle in the Antarctic marine boundary layer. Journal of Geophysical Research, 94(D7):9818-9830 (1989).

Atmospheric sampling was conducted aboard the R/V Polar Duke from March 21 to April 27, 1986 in the southern Drake Passage and in the coastal waters west of the Antarctic Peninsula. Average atmospheric concentrations (n=6) of sulfur dioxide (SO₂) vapor, aerosol methane-sulfonate (CH₃SO₃^-), and aerosol non-sea-salt sulfate (nss-SO₄⁼) were 0.36, 0.22, and 0.34 nmol m^-3, respectively. Cascade impactor data indicated that >85% of the masses of both CH₃SO₃^- and nss-SO₄⁼ were on particles of <0.25-µm mean aerodynamic radius. Average concentrations (n=8) of CH₃SO₃^- - and nss-SO₄⁼ in precipitation were 0.09 and 0.57 µm, respectively. Box model calculations based on this limited data suggest a total sulfur removal rate from the local marine boundary layer of 0.3-7.2 µmol m^-2 day^-1. This removal approximately balances the oceanic source of dimethylsulfide (DMS) sulfur of 1.2-4.4 µmol m^-2 day^-1 (�100%) estimated by Berresheim (1987) from data obtained during the same cruise. The box model calculations also suggest that heterogeneous SO₂ oxidation may be the major pathway for DMS to sulfate conversion (~75%) and/or that other sources of sulfate may not be negligible. Observed mineral aerosol and Rn-222 concentrations were low but slightly elevated above "pure" remote marine background levels, suggesting a weak but discernible continental character in sampled air. Uncertainties are large because of the limited sampling time, study area, and numbers of samples obtained; but overall, the sulfur cycle in the coastal Antarctic marine boundary layer appears not to differ remarkably from that in other remote marine regions.

Qiyu, L., and M.C. Pazos. Drifting buoy data from western tropical Pacific for the period February 1, 1986 through February 28, 1989. NOAA Data Report, ERL AOML-14 (PB90-113978), 131 pp. (1989).

The report contains satellite-tracked buoy data collected in the western tropical Pacific Ocean as part of The People's Republic of China and U.S. cooperative study Air-Sea Interaction in the Western Tropical Pacific program. The data report will cover the deployed drifting buoys from cruises 1 to 4. One of the tables details deployment times and locations and end times and locations of each buoy.

Rao, R.R., R.L. Molinari, and J.F. Festa. Evolution of the climatological near-surface structure of the tropical Indian Ocean. Part I: Description of mean montthly mixed layer depth and sea-surface temperature, surface current, and surface meteorological fields. Journal of Geophysical Research, 94(C8):10,801-10,815 (1989).

Mean monthly mixed layer depth (MLD), sea-surface temperature (SST), and surface current climatologies are generated for the tropical Indian Ocean. In addition, surface meteorological climatologies are produced for those variables which could influence the evolution of the MLD and SST fields. Only the MLD climatology is described in detail, as climatologies for the other variables have appeared previously in the literature. The sum of the annual and semi-annual harmonics account for greater than 75% of the energy in the MLD time series over most of the basin. The amplitude of the annual signal is greater than 20 m between 10°S and 25°S, with deepest MLDs observed during the southern hemisphere winter. The south-central Arabian Sea, between the equator and 10°N, and the northern Arabian Sea are also regions of larger annual harmonic amplitude (>15 m). The amplitude of the semi-annual harmonic is largest in the central Arabian Sea (>25 m). Deepest MLDs are observed there during the height of the two monsoon seasons. Correlation coefficients are computed between MLD and SST and several other oceanographic and meteorological variables to explore possible causal relationships. Net energy flux through the sea surface can account for 75% of the variance in the SST and MLD time series over most of the region south of the equator. Large coefficients are also observed in the northwestern Arabian Sea. Correlations between SST and MLD and surface currents are, in general, small throughout the region with maxima observed in the central Arabian Sea, in the vicinity of the South Equatorial Current and in the extreme eastern equatorial Indian Ocean. These correlations are examined in more detail in Part II of this study in which simple models of mixed layer dynamics are employed.

Rappaport, E.N., and P.G. Black. The utility of special sensor microwave/imager data in the operational analysis of tropical cyclones. Extended Abstracts, 18th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, May 16-19, 1989. American Meteorological Society, Boston, J21-J24 (1989).

No abstract.

Rona, P.A., and D.A. Clague. Geologic controls of hydrothermal discharge on the northern Gorda Ridge. Geology, 17(12):1097-1101 (1989).

An investigation of a 10 x 10 km area near an axial high of the rift valley of the northern Gorda Ridge by using bathymetry, side-scan sonar, and bottom photography where prior water-column surveys indicated ongoing high-temperature hydrothermal discharge reveals that the discharge is localized by specific tectonic and volcanic conditions. The discharge occurs where faults having a predominant ridge-parallel and an anomalous subsidiary ridge-oblique tectonic trend intersect at the southern end of a linear ridge on the east wall and at another site at the base of the east wall of the rift valley. Present and past hydrothermal discharge in this area is controlled by the intersection of an axis-parallel tectonic trend common to all spreading centers having axis-oblique trends related to the regional stress field near the shallowest and volcanically most productive part of the ridge segment.

Rona, P.A., and K.G. Speer. An Atlantic hydrothermal plume: Trans-Atlantic Geotraverse (TAG) area, Mid-Atlantic Ridge crest near 26°N. Journal of Geophysical Research, 94(B10):13,879-13,893 (1989).

The physical characteristics of an Atlantic hydrothermal plume and its seafloor sources are described from the first data set of water column properties associated with a high-temperature source area at a slow-spreading oceanic ridge. The observations comprise five near-bottom tows of a camera (color video and still) temperature sensor array through the buoyant portion and 23 conductivity-temperature-depth (CTD) profiles through the neutrally buoyant portion of the plume made at the Trans-Atlantic Geotraverse hydrothermal field in the rift valley of the Mid-Atlantic Ridge at 26°08'N, 44°49'W in July 1985. The source area is a mound up to 250 m wide and 50 m high constructed primarily of massive sulfides between depths of 3,620 and 3,670 m at the base of the east wall. Flow and discharge regimes systematically changed from the center to the edge of the mound. High-temperature black smokers vented at fast rates (>1 m/s) from discrete sulfide chimneys and at slow rates from fractures, and clear solutions vented at slow rates from diffuse sources in the inner zone of the mound; intermediate-temperature blue-white and white smokers vented at slow rates from discrete sulfide/sulfate chimneys, and clear solutions vented from diffuse sources in the middle zone; patchy, diffuse discharge of clear solutions through sulfide talus occurred in the outer zone. The diffuse discharge of clear solutions and the discrete discharge from the white smokers were observed to turbulently rise up to several meters above the seafloor where the discharge was laterally advected in prevailing laminar flow at several centimeters per second. A convective heat flux of 8.8 x 10⁶W for only the black anomalies was measured with the towed array; this value is intermediate between values estimated for entire vent fields at the fast-spreading East Pacific Rise. Discharge from the black smokers rose to form the neutrally buoyant portion of the plume that was cold and fresh relative to surrounding seawater, where it attained density equilibrium between 190 and 350 m above the mound. In contrast, hydrothermal plumes observed in the Pacific were warm and salty relative to surrounding seawater. The difference is attributed to the effect on plume density of entrainment during rise through opposite salinity profiles that decrease downward in the Atlantic and increase downward in the Pacific, resulting in different temperature-salinity compensations at neutral buoyancy. The temperature difference between the neutrally buoyant portion of the plume and surrounding seawater (negative for the Atlantic; positive for the Pacific) is not a unique function of convective heat flux from a source area, as a consequence of both the effect of the entrainment of salinity on plume density and the separation of diffuse and discrete components of discharge. The hydrothermal plume and the hydrothermal mound are inferred to have grown in size and complexity in response to the development of hydrothermal flow and discharge regimes for at least the past 10⁴ years.

Rosenfeld, L.K., R.L. Molinari, and K.D. Leaman. Observed and modeled annual cycle of transport in the Straits of Florida and east of Abaco Island, the Bahamas (26.5°N). Journal of Geophysical Research, 94(C4):4867-4878 (1989).

Direct velocity observations were collected with a free-fall acoustic velocity profiler along an east-west section extending 65 km offshore of Abaco Island, the Bahamas (26.5°N). The section, which includes five stations, was occupied 14 times between September 1984 and September 1987. The two inshore stations were located on the continental slope, and the three offshore stations were located over the abyssal plain (at depths approaching 4,700 m). The average total section transport between the surface and 2,500 m (the portion of the water column best sampled) was 10 Sv (1 Sv = 10⁶ m³/s) to the south. The range of transports is 40 Sv with maximum northward transport observed during April 1985 (5.3 Sv) and maximum southward transport observed during April 1986 (34.8 Sv). The average flow above 800-900 m is to the north at the four westernmost stations and is to the south below 800-900 m and over most of the easternmost station. The southward flow includes the Deep Western Boundary Current. Strong vertical shears extend to 1,100 m. An approximation for the upper layer (above 1,100 m) baroclinic transport has a mean of 12.2 Sv to the north and a range of 15 Sv. Results from a two-layer and a one-and-a-half-layer wind-driven model are compared with the annual cycles of total and upper layer transport, as determined from the observations. The barotropic transport from the two-layer model has a range of the order of ±10 Sv, with a winter maximum and fall minimum. The range of the baroclinic transport from the one-and-a-half-layer model is an order of magnitude smaller and of opposite sign. Although there are similarities between the observations and the results of both models, the small signal-to-noise ratio precludes definitive confirmation of the annual cycle. The situation east of the Bahamas, where the two models give very different predictions, is compared with the Straits of Florida, where both models predict an annual cycle similar to that observed for the total transport. The roles played by topography and local and remote wind forcing in producing these results are discussed.

Shapiro, L.J. The relationship of the quasi-biennial oscillation to Atlantic tropical storm activity. Monthly Weather Review, 117(7):1545-1552 (1989).

Monthly averaged 30 and 50 mb zonal winds at Balboa are used to determine objectively the relationship of the quasi-biennial oscillation (QBO) to seasonal (August through October) Atlantic tropical storm activity during the years 1952-1986. The largest correlations between storm activity and the 30 mb wind are found in June, which is three months before the center of the season. Extrapolation and direct calculation confirm a near in-phase relationship between tropical storm activity and the zonal wind at about 50 mb. Zonal winds filtered to remove periods 1 yr are used to establish correlations between the QBO and tropical storm activity for 1955-1983 that are essentially independent of the month considered. A correlation at 30 mb is established with a conservative estimate of true skill, from both in-phase and out-of-phase information, that explains 30% of the variance in storm activity. The skill is much greater than that estimated from seasonal classifications of the QBO. The statistics are resilient to removal of the effects of the El Ni�o cycle. When El Ni�o years are explicitly excluded, the true skill explains an estimated 32% of the variance. Low-latitude storms are even more strongly related to the QBO. Physical mechanisms possibly responsible for the observed associations are discussed in light of these results. A mechanism for the observed correlations is suggested that emphasizes the difference between lower-tropospheric steering and the lower-stratospheric zonal wind. The relationships of the results, and suggested physical mechanism, to those of Gray are considered.

Shapiro, L.J. Vortex evolution on a beta plane. Preprints, 18th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, May 16-19, 1989. American Meteorological Society, Boston, 98-99 (1989).

No abstract.

Shay, L.K., R.L. Elsberry, and P.G. Black. Vertical structure of the ocean current response to a hurricane. Journal of Physical Oceanography, 19(5):649-669 (1989).

During the passage of Hurricane Norbert in 1984, the Hurricane Research Division of NOAA conducted a planetary boundary-layer experiment that included the deployment of airborne expendable current profilers (AXCP). A total of 16 AXCPs provided, for the first time, high-resolution vertical profiles of currents and temperatures in hurricanes wind conditions. This study focuses on the vertical structure of the near-inertial baroclinic currents excited by the passage of this hurricane. The transient, hurricane-induced currents are isolated from the AXCP profiles in Norbert by subtracting a spatially-averaged current. Near the center of Hurricane Norbert, the WKBJ-scaled vertical wavenumber spectra are a decade greater than the Garrett-Munk spectra (GM75). The first ten linear, baroclinic-free modes are calculated from the spatially-averaged, Brunt-Väisälä frequency. To allow a more direct comparison with the AXCP observations in the high-wind regime, the near-inertial response for the three-dimensional velocities is simulated by superposing a hurricane-like wind stress field onto the first ten baroclinic modes. About 70% of the current variance in Hurricane Norbert can be explained by a sum of only the first four near-inertial modes. Most of the ocean current variability can be accounted for by the wind stress curl, although the direct effect of the wind stress and the stress divergence do contribute to the observed current variance within 30-60 km from the storm. However, these last two effects rapidly diminish after one inertial period. Although the energy input by the hurricane forcing is spread over all of the vertical wavelengths, most of the energy is contained in the gravest four vertical modes which then govern the dynamics in the wake region.

Speer, K., and P.A. Rona. A model of an Atlantic and Pacific hydrothermal plume. Journal of Geophysical Research, 94(C5):6213-6220 (1989).

A turbulent entrainment model of a hydrothermal plume was modified to include the effects of vertical structure in the background temperature and salinity fields. Owing to the stably-stratified salinity field in the Pacific, relatively warm, salty water spreads at an equilibrium level, where the plume density equals the ambient density. In contrast, the unstable salinity profile in the Atlantic gives the plume added buoyancy, and it continues to rise to an equilibrium level where it is relatively cool and fresh. The net entrainment of surrounding seawater is greater in the Atlantic plume model than in the Pacific plume model for the same buoyancy flux. Recent data from the TAG hydrothermal field at 26°N on the Mid-Atlantic Ridge and data from a vent field on the Endeavor segment of the Juan de Fuca Ridge are compared to model results. The model predicts the penetration height and theta-S characteristics of the Atlantic plume, and explains some of the differences between the observed Atlantic and Pacific hydrothermal plumes.

Thacker, W.C. The role of the Hessian matrix in fitting models to measurements. Journal of Geophysical Research, 94(C5):6177-6196 (1989).

A numerical model can be fit to data by minimizing a positive quadratic function of the differences between the data and their model counterparts. The rate at which algorithms for computing the best fit to data converge depends on the size of the condition number and the distribution of eigenvalues of the Hessian matrix, which contains second derivatives of this quadratic function. The inverse of the Hessian can be identified as the covariance matrix that establishes the accuracy to which the model state is determined by the data; the reciprocals of the Hessian's eigenvalues representing the variances of linear combinations of variables determined by its eigenvectors. The aspects of the model state that are most difficult to compute are those about which the data provide the least information. A unified formalism is presented in which the model may be treated as either strong or weak constraints, and methods for computing and inverting the Hessian matrix are discussed. Examples of the uncertainties in the best-fit analyses using an oceanographic model are given for several different sets of hypothetical data.

Thompson, G., S.E. Humphris, C. Lalou, and P.A. Rona. Hydrothermal activity on the Mid-Atlantic Ridge. Proceedings, 6th International Symposium on Water-Rock Interaction, Malvern, UK, August 3-8, 1989. A.A. Balkema, Rotterdam, The Netherlands, 679-681 (1989).

Two active hydrothermal vent sites are known on the Mid-Atlantic Ridge; one at 26°N Trans Atlantic Geotraverse (TAG) and the other at 23°N (Snakepit). Both fields have high temperature sulfide deposits of pyrite, chalcopyrite and sphalerite, but the Snakepit site differs in having pyrhotite as a dominant phase. Secondary Cu-Fe sulfides, oxides, chlorides, native copper and gold, as well as aragonite, are abundant at TAG, but absent at Snakepit. The TAG site has Mn-oxide deposits up to 120,000 yrs in age. High temperature sulfides range up to 40,000 yrs old and indicate a number of discrete, punctuated episodes of hydrothermal activity separated by periods of quiescence. Snakepit activity appears to have begun about 5000 yrs ago, and was followed by a new, recent active period. Fluid flow at both sites is controlled by tectonic faulting and is related to magmatic intrusions.

Tziperman, E., and W.C. Thacker. An optimal-control/adjoint-equations approach to studying the oceanic general circulation. Journal of Physical Oceanography, 19(10):1471-1485 (1989).

An efficient procedure is presented for analyzing oceanographic observations with the aid of a general circulation model. Poorly known model parameters, such as eddy mixing coefficients, surface forcing and tracer boundary fluxes, can be calculated by fitting model results to observations. Optimal estimates for all model fields, including the observed ones, can then be computed by running the model with the best-fit values of the calculated parameters. Information about the resolution and the error-covariances of the model parameters can be computed. This information is shown to be very valuable for critically evaluating how well the data determine the parameter's values. An adjoint model, similar in structure to the numerical model, uses information on model-data misfit to improve estimates of the unknown model parameters, and improve the fit to observations. The procedure is illustrated using simulated data and a simple, barotropic, nonlinear, quasi-geostrophic model. Examples are discussed in which friction parameters, wind forcing, and the steady-state circulation are determined from simulated vorticity and streamfunction observations.

Vazquez, G.F., J.-Z. Zhang, F.J. Millero. Effect of transition metals on the rate of the oxidation of H₂S in seawater. Geophysical Research Letters, 16:1363-1366 (1989).

Recent measurements on the oxidation of H₂S in the Black Sea yielded rates that were ten times faster than expected. To determine if this increase was due to trace metals, measurements have been made on the oxidation of H₂S in seawater with added transition metals. Below a concentration level of 100 nM, none of metals except Fe2+ affect the rate of oxidation. At higher concentrations, the rates increase for all the metals except Zn2+. The increase in the rates followed the order Fe2+ > Pb2+ > Cu2+ > Fe3+ > Cd2+ > Ni2+ > Co2+ > Mn2+. The increase in the rates below sulfide precipitation appears to be related to the formation of MHS+ ion pairs that have a higher rate of oxidation than HS-. Only Fe2+ and Mn2+ have concentrations high enough to be effective in influencing the rate of oxidation of H₂S in the waters of anoxic basins and sediments. The estimated rates of the oxidation of H₂S in the Black Sea using the laboratory measurements were found to be in reasonable agreement with the measured values. Since CuHS+ has a higher rate of oxidation than HS-, it cannot be used to explain the stability of H₂S in oxic seawater. A more likely choice is ZnHS+.

Venne, M.G., W.A. Lyons, C.S. Keen, P.G. Black, and R.C. Gentry. Explosive supercell growth: A possible indicator of tropical storm intensification? Preprints, 24th Conference on Radar Meteorology, Tallahassee, FL, March 27-31, 1989. American Meteorological Society, Boston, 545-548 (1989).

No abstract.

Wilburn, A.M., E. Johns, and M.H. Bushnell. Current velocity and hydrographic observations in the southwestern North Atlantic Ocean: Subtropical Atlantic Climate Study (STACS), 1988. NOAA Data Report, ERL AOML-13 (PB89-230825), 89 pp. (1989).

The primary objectives of the Subtropical Atlantic Climate Studies (STACS) program are to increase our understanding of the dynamics of the North Atlantic circulation and the role of ocean circulation in global climate, to develop the capability to monitor the climatically important processes, and to provide data needed in the development of the coupled ocean-atmosphere general circulation models to be used for global climate prediction. In particular, the mechanisms by which the ocean transports heat to balance the net radiation deficit at northerly latitudes are being studied.

Willis, P.T., and A.J. Heymsfield. Hurricane microphysical trajectories. Preprints, 18th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, May 16-19, 1989. American Meteorological Society, Boston, 75-76 (1989).

No abstract.

Willis, P.T., and A.J. Heymsfield. Structure of the melting layer in mesoscale convective system stratiform precipitation. Journal of the Atmospheric Sciences, 46(13):2008-2025 (1989).

This study examines the aircraft observations and theoretical evolution of particles above, through, and below the melting layer in the stratiform region associated with a mesoscale convective system (MCS). The aircraft data were obtained from an advecting spiral descent where the descent rate approximately corresponded to the typical hydrometeor fall speeds. The microphysical and thermodynamic measurements not only allowed us to characterize the particle evolution, but also enabled us to compare them with the theoretical evolution of the particles in the melting layer and to quantify the associated heating and cooling rates. Even though complete melting requires a fairly deep layer, most of the mass melts, and thus most of the cooling occurs, in a thin layer above the location of the radar bright band. Based upon the magnitude of vertical velocity fluctuations, the layers below the melting layer appear to be decoupled from those above. The ice water content above the melting layer is two to three times the liquid water content below the melting layer. The production of a few, very large, aggregates is dramatic after the onset of melting, due in part to a melting-induced increase in the terminal velocity difference between similar-sized hydrometeors. The radar reflectivity maximum (bright band) is due to these relatively few, very large, aggregates that survive to warmer temperatures. The reflectivity maximum is depressed well below the isothermal layer and the level where most of the ice mass is melted. Above the melting layer, small crystals are replenished by a fragmentation or breakup process.

Willis, P.T., and P. Tattleman. Drop-size distributions associated with intense rainfall. Journal of Applied Meteorology, 28(1):3-15 (1989).

The probability of occurrence of extreme rainfall rates is reviewed. The drop-size distributions associated with a range of high rainfall rates are examined using data from tropical storms and hurricanes. Mean drop-size distributions are presented for a range of high rainfall rates, as well as a Gamma-distribution fit to the entire set of normalized drop-size distributions. This fit forms the basis for a model drop-size distribution for intense rain. The goodness of fit of the model is examined by comparing it with independent drop-camera measurements of high-rain-rate distributions from several geographic locations. The slope of exponential fits to the distributions are examined for constancy with rainfall rate and are generally found to decrease with increasing rainfall rate.

Willoughby, H.E., W.P. Barry, and M.E. Rahn. Real-time monitoring of Hurricane Gilbert. Preprints, 18th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, May 16-19, 1989. American Meteorological Society, Boston, 220-221 (1989).

No abstract.

Willoughby, H.E., J. Masters, and C.W. Landsea. A record minimum sea level pressure observed in Hurricane Gilbert. Monthly Weather Review, 117(12):2824-2828 (1989).

On 13 September 1988, Hurricane Gilbert attained an extreme minimum sea level pressure, estimated to be 885 hPa from aircraft reconnaissance reports at the time. Postseason analysis indicates that the flight-level pressure, P, upon which this figure is based requires correction upward. In typhoons with sea level pressure <900 hPa, comparison between sea level pressures measured by dropsonde and those estimated by the same method used in Gilbert indicates that, in addition to the error in P, the estimation has a bias toward low pressure. Although the aircraft did not release a dropsonde in the eye at minimum pressure, it is possible to calculate hydrostatic sea level pressures by assuming a variety of plausible thermal structures below flight level. With corrected P, both the statistical extrapolation with its bias removed and the hydrostatic calculations show that a revised value of 888 ± 2 hPa is closer to the true minimum sea level pressure. The standard deviation of the various approximations means that the probability is <3% that the actual minimum failed to reach a value below 892 hPa, the old record for a hurricane in the Atlantic Basin set by the Labor Day Hurricane of 1935.

Wood, V.T., and F.D. Marks. Hurricane Gloria: Simulated land-based Doppler velocities reconstructed from airborne Doppler radar measurements. Extended Abstracts, 18th Conference on Hurricanes and Tropical Meteorology, San Diego, CA, May 16-19, 1989. American Meteorological Society, Boston, 115-116 (1989).

No abstract. **1988**

Black, P.G., R.L. Elsberry, and L.K. Shay. Airborne surveys of ocean current and temperature perturbations induced by hurricanes. In Advances in Underwater Technology, Ocean Science, and Offshore Engineering, Vol. 16, Oceanology '88. Graham and Trotman, London, 51-58 (1988).

No abstract.

Black, P.G., R.L. Elsberry, L.K. Shay, R.P. Partridge, and J.D. Hawkins. Atmospheric boundary layer and oceanic mixed layer observations in Hurricane Josephine obtained from air-deployed drifting buoys and research aircraft. Journal of Atmospheric and Oceanic Technology, 5(6):683-698 (1988).

Three drifting buoys were successfully air dropped ahead of Hurricane Josephine. This deployment resulted in detailed simultaneous measurements of surface wind speed, surface pressure, and subsurface ocean temperature during and subsequent to storm passage. This represents the first time that such a self-consistent data set of surface conditions within a tropical cyclone has been collected. Subsequent NOAA research aircraft overflights of the buoys, as part of a hurricane planetary boundary-layer experiment, showed that aircraft wind speeds, extrapolated to the 20 m level, agreed to within ±2 m s^-1, pressures agreed to within ±1 mb, and sea-surface temperatures agreed to within ±0.8°C of the buoy values. Ratios of buoy peak 1 min wind (sustained wind) to 1/2 h mean wind >1.3 were found to coincide with eyewall and principal rainband features. Buoy trajectories and subsurface temperature measurements revealed the existence of a series of mesoscale eddies in the subtropical front. Buoy data revealed storm-generated, inertia-gravity-wave motions superposed upon mean current fields, which reached a maximum surface speed >1.2 m s^-1 immediately following storm passage. A maximum mixed-layer temperature decrease of 1.8°C was observed to the right of the storm path. A temperature increase of 3.5°C at 100 m and subsequent decrease of 4.8°C following storm passage indicated a combination of turbulent mixing, upwelling, and horizontal advection processes.

Broecker, W.S., D. Oppo, T.-H. Peng, W. Curry, M. Andree, W. Wolfli, and G. Bonani. Radiocarbon-based chronology for the ¹⁸0/¹⁶0 record for the last deglaciation. Paleoceanography, 3(4):509-515 (1988).

A radiocarbon-calibrated box model for today's ocean suggests that a lag of about 1750 years should exist between the arrival of the mid-point of the deglaciation ¹⁸O signal in the deep Atlantic Ocean and its arrival in the deep Pacific Ocean. In order to assess the actual lag, we have carried out accelerator radiocarbon measurements on two cores from the Atlantic Ocean and one core from the Pacific Ocean. Although the results are not definitive, there is a suggestion that the actual time lag was about 1000 years.

Broecker, W.S., R.H. Wanninkhof, G. Mathieu, T.-H. Peng, S. Stine, S. Robinson, A. Herczeg, and M. Stuiver. The radiocarbon budget for Mono Lake: An unsolved mystery. Earth and Planetary Science Letters, 88:16-26 (1988).

Since 1957 the ¹⁴C/C ratio of the dissolved inorganic carbon in Mono Lake has risen by about 60%. The magnitude of this increase is about four times larger than that expected from the invasion of bomb-produced ¹⁴C from the atmosphere. We have eliminated the following explanations: (1) measurement error; (2) an unusually high physical exchange rate for non-reactive gases; (3) inorganic enhancement of the CO₂ exchange rate; and (4) biological enhancement of the CO₂ exchange rate. Clandestine disposal of waste radiocarbon remains a dark-horse explanation. In the course of our investigations we have uncovered evidence for at least one episodic input of radiocarbon-free carbon to the lake over the last 1000 years. We speculate that this injection was related to a hydrothermal event resulting from sublacustrine volcanic activity.

Burpee, R.W. Forecaster biography: Grady Norton--hurricane forecaster and communicator extraordinaire. Weather and Forecasting, 3(3):247-254 (1988).

No abstract.

Campbell, A.C., M.R. Palmer, G.P. Klinkhammer, T.S. Bowers, J.M. Edmond, J.R. Lawrence, J.F. Casey, G. Thompson, S. Humphris, P.A. Rona, and J.A. Karson. Chemistry of hot springs on the Mid-Atlantic Ridge. Nature, 335(6190):514-519 (1988).

The first hydrothermal fluid samples collected along the slow-spreading Mid-Atlantic Ridge (MAR) are remarkably similar in composition and temperature to fluids collected along the shallower, faster-spreading East Pacific Rise (EPR). The MAR fluids, like those from the EPR, appear to be in equilibrium with a greenschist-facies mineral assemblage. In contrast to the EPR, the more fractured nature of the MAR apparently allows fluids at one of the MAR sites to interact with weathered basalt.

Chew, F. Comments on "Gulf Stream kinematics along an isopycnal trajectory." Journal of Physical Oceanography, 18(6):932-933 (1988).

No abstract.

Clarke, T.L., J.R. Proni, D.A. Seem, and J.J. Tsai. Joint CGS-AOML (Charting and Geodetic Service-Atlantic Oceanographic and Meteorological Laboratory) acoustical bottom echo-formation research, Part 1: Literature search and initial modeling results. NOAA Technical Memorandum, ERL AOML-66 (PB88-202007), 82 pp. (1988).

A literature survey has found work dealing with the problem of echo-formation for rough sedimentary bottoms. The main attempts at practical application have been at frequencies lower than those used for echo-sounding work. A model has been formulated that includes the effect of surface scattering and volume scattering in a unified manner. This model has been implemented on the AOML computer and exercised for a variety of bottom types and echo-sounding frequencies.

Clarke, T.L., J.R. Proni, and L.C. Huff. Joint CGS-AOML (Charting and Geodetic Service-Atlantic Oceanographic and Meteorological Laboratory) acoustical bottom echo-formation research, Part 2: Field experiment results and recommendations for echo-sounder design. NOAA Technical Memorandum, ERL AOML-67 (PB89-152417), 130 pp. (1988).

Field experiments were conducted to test and verify a mathematical model that has been developed to assess the effects of bottom roughness and material properties on bottom echo shape. The physical basis of the model is reviewed and model output is presented. The experiments were conducted in lower Chesapeake Bay and involved taking high resolution acoustic data at a number of frequencies and taking supporting sediment samples. A unique, high-resolution bottom profiler was used to measure bottom roughness profiles for input to the model. While model predictions were in general agreement with the data, fine structure was observed in the echoes that could not be explained by the existing model. An extension to the model has been developed that is able to account for this structure. The essential ingredient of this extension is to consider bottom surface scattering as arising from a number of statistically independent patches within the transducer beam. This revised model should lead to improved predictions of bottom echo waveforms for echo-sounder design. The algorithm developed for removing ship motion from the observations suggests a design for a new type of echo-sounder detector circuit based on an energy threshold. This circuit could be easily implemented with modern digital signal processing (DSP) circuits, and it might be suitable for retro-fitting to existing echo-sounders.

Colin, C., and S.L. Garzoli. High-frequency variability of in-situ wind, temperature, and current measurements in the equatorial Atlantic during the FOCAL/SEQUAL experiment. Oceanologica Acta, 11(2):139-148 (1988).

The high-frequency variability of in-situ wind measurements in the western (1°N, 29°W) and eastern (0°, 4°W) equatorial Atlantic are described and for the first time compared. The data were obtained from meteorological sensors placed respectively on St. Peter and St. Paul Rocks and at the top of a surface buoy moored in the Gulf of Guinea during the FOCAL/SEQUAL experiment from February 1983 to September 1984.

Dagg, M.J., P.B. Ortner, and F. Al-Yamani. Wintertime distribution and abundance of copepod nauplii in the northern Gulf of Mexico. Fishery Bulletin, 86(2):319-330 (1988).

Copepod nauplii were collected from continental shelf waters in three regions of the northern Gulf of Mexico during winters between 1981 and 1984, off Cape San Blas, Florida, off the Mississippi River delta, and off of Galveston, Texas. Some statistically significant (P < 0.05) patterns in the abundance and distribution of nauplii were observed: significant interannual variability in naupliar concentrations within the region around the Mississippi River delta; naupliar concentrations in the upper 10 m decreased in the onshore-offshore direction for two of four comparisons; naupliar concentrations in the upper 10 m differed regionally in two of three comparisons; and naupliar concentrations correlated with chlorophyll concentrations in nauplii (number per m s³) within a water column were 2-10 times greater at stations influenced by the Mississippi River plumes than in the other two regions. This condition is attributed to vertical stratification imparted to the water column by the inflowing low salinity water from the Mississippi River. The authors conclude that the physical stratification provides a mechanism for the establishment of high concentrations of nauplii that otherwise would not exist in the winter months on the continental shelf.

DeMaria, M. The effect of physical processes on the convergence of Machenhauer's normal mode initialitzation scheme. Preprints, 8th Conference on Numerical Weather Prediction, Baltimore, MD, February 22-25, 1988. American Meteorological Society, Boston, 751-757 (1988).

No abstract.

DeMaria, M., and J.D. Pickle. A simplified system of equations for simulation of tropical cyclones. Journal of the Atmospheric Sciences, 45(10):1542-1554 (1988).

A simplified system of equations which can simulate the development and mature stages of tropical cyclones is presented. The model is similar to that presented by Ooyama, except that the assumption of incompressible fluid layers is relaxed. Instead, the governing equations for a compressible fluid in isentropic coordinates are discretized vertically by considering three fluid layers with constant potential temperature. This makes the inclusion of thermodynamic processes more straightforward. The governing equations in the adiabatic case are mathematically equivalent to the equations used by Ooyama, except with an extra term in the pressure gradient force. The model equations are solved using a spectral method where the basis functions are the normal modes of the linearized equations. Numerical simulations show that the model sensitivity to vertical stability, sea surface temperature and midlevel moisture are similar to results from more general models. The sensitivity to these factors can be explained qualitatively by consideration of the vertical stability factor used in the cumulus parameterization. The sensitivity to latitude is investigated in more detail in previous work. Low-latitude storms are smaller than high-latitude storms, but intensify more rapidly initially. This difference is related to the radial positioning of the diabatic heating which is much closer to the storm center for low-latitude storms. This occurs since the air in the boundary layer can penetrate closer to the storm center when the Coriolis force is smaller. The model is also initialized with climatological values of sea surface temperature as a function of latitude appropriate for the western Pacific. Despite its simplicity, the model can reproduce the observed variations of storm size and intensity with latitude.

Dodge, P.P. A climatology of rainbands observed by coastal radars in GALE. Reports of GALE/CASP Preliminary Analysis Workshop, Virginia Beach, VA, November 2-6, 1987. GALE Project Office, NCAR, Boulder, 19-22 (1988).

No abstract.

Eberhart, G.L., P.A. Rona, and J. Honnorez. Geologic controls of hydrothermal activity in the Mid-Atlantic Ridge rift valley: Tectonics and volcanics. Marine Geophysical Researches, 10(3-4):233-259 (1988).

The rift valley at three widely separated sites along the Mid-Atlantic Ridge is characterized using geological and geophysical data. An analysis of bottom photographs and fine-scale bathymetry indicates that each study area has a unique detailed geology and structure. Spreading rates are apparently asymmetric at each site. Relationships between tectonic and volcanic structure and hydrothermal activity show that various stages in the evolution of the rift valley are most favorable for seafloor expression of hydrothermal activity. In a stage found at 28°08'N, site 1 (TAG), the rift valley is narrow, consisting of both a narrow volcanically active valley floor and inner walls with small overall slopes. High-temperature hydrothermal venting occurs along the faster spreading eastern inner wall of this U-shaped rift valley. Site 2 (16°46'N) has a narrow valley floor and wide block faulted walls and is at a stage where the rift valley is characterized by a V-shape. No neovolcanic zone is observed within the marginally faulted, predominantly sedimented floor and hydrothermal activity is not observed. The rift valley at site 3 (14°54'N), with postulated extrusive volcanic activity and a stage in valley evolution tending toward a U-shape, shows evidence of hydrothermal activity within the slightly faster spreading eastern inner wall. Evidence for tectonic activity (inward- and outward-facing faults and pervasive fissuring) exists throughout the wide inner wall. Hydrothermal activity appears to be favored within a U-shaped rift valley characterized by a narrow neovolcanic zone and secondarily faulted inner walls.

Enfield, D.B. Is El Niño becoming more common? Oceanography, 1(2):23-27 (1988).

No abstract.

Fine, R.A., and R.L. Molinari. A continuous deep western boundary current between Abaco (26.5°N) and Barbados (13°N). Deep-Sea Research, Part A 35(9):1441-1450 (1988).

Chlorofluoromethane (F-11) and hydrographic data show that the Deep Western Boundary Current (DWBC) in the North Atlantic Ocean is a continuous feature of the mean circulation between Abaco and Barbados. Two cores of high F-11 concentrations are coincident with the DWBC. The deep core located between 3200 and 4600 m transports North Atlantic Deep Water. The shallow core at 1000-1700 m transports recently formed Subpolar Mode Water. Classical LSW with a potential temperature of about 3.3° theta, which is found between 2000 and 3000 m, has a minimum in F-11 concentration because it has not been ventilated recently.

Franklin, J.L., and S.J. Lord. Comparisons of VAS and Omega dropwindsonde thermodynamic data in the environment of Hurricane Debby (1982). Monthly Weather Review, 116(8):1690-1701 (1988).

Synoptic-scale thermodynamic fields in the environment of Hurricane Debby (1982) determined from two sets of VAS soundings (VAS1, VAS2) are compared with those obtained from in-situ data (INS). VAS1 sounding were derived from an iterative solution of the radiative transfer equation with manual quality control. VAS2 soundings, which represent the present state-of-the-art, were derived from a simultaneous solution of the transfer equation with objective quality control. In situ data were obtained primarily from Omega dropwindsondes. Comparisons are made for 0000 UTC 16 September 1982 at the mandatory pressure levels up to 400 mb. The integrated effect of VAS-INS differences is estimated by comparing 400 mb geopotential height fields and their associated gradient winds. The comparisons show that the VAS1-INS temperature differences are not spatially uniform at most levels, due largely to the influence of moisture. The quality of the VAS2 data is much improved over VAS1; the effect of moisture is not noticeable. However, the VAS2 analyses still show spatially nonuniform differences from INS at some levels. Thus, VAS gradient data may be of irregular quality on the synoptic scale. Geopotential height fields at 400 mb imply gradient wind differences from INS of up to 12 m s^-1 for VAS 1 and 6 m s^-1 for VAS2. The VAS2 sounding set could be improved further by the use of manual data editing, and a more accurate first-guess of the surface temperature analysis.

Franklin, J.L., S.J. Lord, and F.D. Marks. Dropwindsonde and radar observations of the eye of Hurricane Gloria (1985). Monthly Weather Review, 116(5):1237-1244 (1988).

Two soundings from the eye of Hurricane Gloria (1985) during a period of rapid deepening are described. The soundings were made by Omega dropwindsondes (ODWs) during research flights of the NOAA Hurricane Research Division on 24-25 September 1985. During the 4.7 h between the two ODW drops, Gloria's minimum sea-level pressure fell from 932 to 922 mb. The ODWs indicate substantial warming due to dry adiabatic descent from 580-660 mb. Descent rates are estimated to be about 11 cm s^-1. Near 500 mb, ascent is indicated. Approximately 60% of the 10 mb pressure fall is associated with thermodynamic changes below 500 mb.

Gamache, J.F., F.D. Marks, and R.A. Black. The bulk water budget of Hurricane Norbert (1984) as determined from thermodynamic and microphysical analyses retrieved from airborne Doppler radar. Preprints, 10th International Cloud Physics Conference, Bad Homburg, Federal Republic of Germany, August 15-20, 1988. American Meteorological Society, Boston, 711-713 (1988).

No abstract.

Georges, T.M., D.R. Palmer, R.M. Jones, and J.P. Riley. A survey of acoustic techniques for monitoring El Niño. NOAA Technical Memorandum, ERL WPL-149 (PB88-157615), 58 pp. (1988).

The challenge of understanding the El Niño-Southern Oscillation (ENSO) cycle in the equatorial Pacific Ocean is a test of our abilities to observe, model, and forecast the processes of global climate change. The only viable technology for monitoring the structure, dynamics, and energetics of the ocean interior on the space-time scales of the ENSO signal appears to be acoustic remote sensing. We, therefore, examine how the following acoustic techniques might be used to monitor ENSO-induced changes in the upper ocean: (1) ocean acoustic tomography; (2) a long-range acoustic thermometer; (3) passive monitoring of ambient acoustic noise level; (4) an occulation technique that depends on bottom absorption; and (5) space-time scintillation analysis. We computed the acoustic properties of ocean models based on the 1982-1983 ENSO event and found out how sensitive different acoustic measurables are to the temperature changes that accompany a strong El Niño. In the eastern Pacific, for example, the largest (and earliest) temperature increases occur between 40 and 100 m depth. For long-range (ducted) sound rays to pass through this region without being absorbed by the bottom, the ocean must be at least 4 km deep. Pulse tomography, applied to vertical ocean slices, could adequately sample the temperature and currents in the upper ocen if appropriate receiving arrays were used. The passive listening scheme could monitor changes in the ambient noise level with the onset of El Niño, but it raised many questions about the natural variability of the noise environment. An occulation scheme that uses a vertical receiving array could economically monitor changes in average thermocline depth. The long-range acoustic thermometer could monitor the heat content of the equatorial ocean, a likely ENSO precursor. The horizontal covariance of acoustic scintillations might be used to measure the structure of transverse currents crossing a long acoustic path. If problems in extending the theoretical model to longer ranges can be solved, scintillation analysis could be used to monitor subsurface equatorial currents that transport heat eastward along the equator. Each technique examined offers some remote-sensing potential, but each also poses problems to be solved before its relative advantages in cost, coverage, or convenience over in-situ methods are clear.

Hanes, D.M., C.E. Vincent, D.A. Huntley, and T.L. Clarke. Acoustic measurements of suspended sand concentration in the C²S² experiment at Stanhope Lane, Prince Edward Island, Canada. Marine Geology, 81(1-4):185-196 (1988).

A 3 MHz acoustic concentration meter (ACM) was deployed with electromagnetic flowmeters in the nearshore region in October 1984 at Stanhope Lane, Prince Edward Island, Canada, as a component of the Canadian Coastal Sediment Study. The ACM measured the backscatter of acoustic energy in a vertical beam pattern within approximately 1 m of the seabed. Laboratory calibration experiments were conducted to verify a method for converting acoustic backscatter into suspended sand concentration profiles. The ACM functioned well when there were no air bubbles in the water. Both the suspended sand concentration profiles and the bottom location were measured with an approximately 1 second time resolution and a 1 cm vertical spatial resolution. The suspension of sand is related to the wave and current forcing, and is dominated by events of short duration.

Hannington, M.D., G. Thompson, P.A. Rona, and S.D. Scott. Gold and native copper in supergene sulfides from the Mid-Atlantic Ridge. Nature, 333(6168):64-66 (1988).

In 1985 black smokers and massive sulfide deposits were discovered in the TAG hydrothermal field in the rift valley of the Mid-Atlantic Ridge near latitude 26°08'N (ref. 1). Sulfide samples from chimneys and mounds were recovered by dredging at depths between 3,620 and 3,670 m. Mineralogical and chemical analyses of the samples reveal (1) primary, unaltered Zn-Fe-Cu-sulfides containing 0.8-4.0 ppm Au (0.02-0.12 oz per ton) and (2) secondary Cu-rich sulfides with native copper, formed by supergene alteration of primary Cu-Fe-sulfides, containing up to 16.4 ppm Au (0.48 oz per ton) as free native gold. This is the first reported occurrence of secondary enrichment of gold and copper in recent submarine sulfides. The high gold grades and native copper associated with secondary Cu-sulfides resemble occurrences in some supergene gossans overlying ancient massive sulfide deposits on land.

Hansen, D.V., and C.A. Paul. Vertical motion in the eastern equatorial Pacific inferred from drifting buoys. Oceanologica Acta, 6:27-32 (1988).

Surface current measurements have been obtained from the eastern tropical Pacific Ocean by means of drifting buoys tracked by the NIMBUS and ARGOS satellite systems since 1977. Near-equatorial divergence of Ekman transport is indicated qualitatively by persistent avoidance of the equator by drifters. Upwelling velocity and transport were estimated from the horizontal divergence of surface current fields obtained by optimum interpolation of overall and monthly composite data. The estimated divergence is predominantly meridional. Average upwelling velocity and transport in the region 1.5°N-1.5°S, 80°W-130°W are estimated to be 1.5 m da^-1 and 32 × 10⁶ m³ s^-1. Seasonal variation of the estimated upwelling agrees closely in phase but is larger in magnitude than that implied by the annual and semiannual constituents of 14°C isotherm depth variations in the eastern equatorial Pacific.

Harvey, G.R. Comments on azide and mercuric salts as seawater preservatives, and alkenes in the Gulf of Mexico. Marine Chemistry, 24(2):199-202 (1988).

A homologous series of volatile low molecular weight 1-alkenes was found in the surface waters of the Gulf of Mexico. Previous workers in the Gulf and other tropical waters did not report these compounds but they had poisoned their samples at sea for analysis later. The efficacy of azide and mercuric salts to preserve a representative alkene, 1-heptene, and heptane was tested. Neither salt significantly prevented loss of the hydrocarbons from spiked seawater. The 1-alkenes are most likely the abiotic products of photochemical oxidation and fragmentation of n-alkanes.

Harvey, G.R., and M.S. Young. Ozone in seawater and lake water: A reversible reservoir. Geophysical Research Letters, 15(11):1199-1201 (1988).

Observations made at sea and examination of global ozone monitoring data from oceanic sites indicate that ozone mixing ratios often increase with increasing wind speed. However, the slope of the increase approaches zero at wind speeds above about 6 m sec (13 kts). Subsequent laboratory experiments confirmed that ozone can be purged from any seawater sample whether freshly collected, stored, or from depths of 3,500 m. Samples of Lake Michigan water are purged of ozone in less time than seawater and its capacity is less than that of seawater. The rate of evolution of ozone is increased by altering the pH, changing the ionic strength by the addition of salts, or by evaporation. These results suggest that a significant portion of tropospheric boundary layer ozone mixing ratios could be maintained by a reversible equilibrium with the ocean and lake surfaces.

Houze, R.A., F.D. Marks, and R.A. Black. Mesoscale patterns of ice particle characteristics in Hurricane Norbert. Preprints, 10th International Cloud Physics Conference, Bad Homburg, Federal Republic of Germany, August 15-20, 1988. American Meteorological Society, Boston, 708-710 (1988).

No abstract.

Lautenschlager, M., D.P. Eppel, and W.C. Thacker. Subgrid-parameterization in helical flows. Contributions to Atmospheric Physics (Beiträge zur Physik der Atmosphäre), 61(2):87-97 (1988).

A new parameterization for the turbulent momentum fluxes of an incompressible flow is suggested. Assuming the turbulent field to carry internal structure, the expansion of the subgrid fluxes in terms of average vorticity leads, in addition to subgrid kinetic energy, to subgrid helicity as an extra parameter to characterize this internal structure. In a simple model the expansion coefficients are connected to the resolution scale of the numerical grid model used. It is shown that the new subgrid-helicity dependent terms act against diffusion as they can transport additional rotation into the mean motion. In the limit of vanishing turbulent helicity the new parameterization reproduces the well-known diffusion parameterization of the turbulent fluxes.

Lord, S.J., and J.L. Franklin. Diagnostics of thermodynamic and wind fields in the environment of Hurricane Debby (1982). Preprints, 8th Conference on Numerical Weather Prediction, Baltimore, MD, February 22-25, 1988. American Meteorological Society, Boston, 605-610 (1988).

No abstract.

Lord, S.J., and J.M. Lord. Vertical velocity structures in an axisymmetric, nonhydrostatic tropical cyclone model. Journal of the Atmospheric Sciences, 45(9):1453-1461 (1988).

A statistical analysis of several experiments with different microphysical parameterizations in an axisymmetric, nonhydrostatic tropical cyclone model illustrates the impact of icc-phase microphysics on model vertical velocity structure. The parameterizations are designed to illustrate the effects of (1) thermodynamic input through latent heating, (2) vertical sorting of microphysical species by fall speed, and (3) different rates of the parameterized microphysical conversion processes. The results confirm previous studies on the thermodynamic effect of melting, but they also show that the other factors, namely, fall speed and microphysical conversion rates, are important in determining model vertical velocity structure and evolution. Statistical summaries of updrafts and downdrafts show distinct increases in the intensity and horizontal scale of downdrafts near the melting level when parameterized snow is included. Model storms without snow show a greater percentage of convective-scale updrafts and downdrafts; they intensify more slowly but ultimately become stronger than those that have larger scale vertical velocity structures.

Maul, G.A. English-Spanish bibliography in physical oceanography and climate for the Caribbean Sea and adjacent regions. Intergovernmental Oceanographic Commission of UNESCO, IOC/INF-783, 49 pp. (1988).

No abstract.

Maul, G.A., J.R. Proni, and J.L. Mitchell. On the integration of satellite altimeter data with in-situ oceanographic data to provide precise profiles of absolute dynamic height anomaly. Proceedings, Pacific Congress on Marine Science and Technology (PACON'88), Honolulu, HI, May 16-20, 1988. Marine Technology Society, 9-10 (1988).

No abstract.

Metz, S., J.H. Trefry, and T.A. Nelsen. History and geochemistry of a metalliferous sediment core from the Mid-Atlantic Ridge at 26°N. Geochimica et Cosmochimica Acta, 52(10):2369-2378 (1988).

Fourteen thousand years of hydrothermal deposition are recorded in a metalliferous sediment core recovered from the Trans-Atlantic Geotraverse (TAG) Hydrothermal Field on the Mid-Atlantic Ridge at 26°N. An estimated 26% to >96% of the sediment at this core site is hydrothermally derived as determined from the CaCO₃, Al, and Fe data. Layers of essentially pure vent precipitates contain <3% CaCO₃ and <0.5% Al, with high concentrations of Fe (43%), Cu (4.1%), Zn (1.2%), Mn (1.1%), V (480 ppm), Pb (175 ppm), Cd (32 ppm) and Hg (3.8 ppm). Sediment accumulation rates vary from ~1 to >30 g/cm²/1,000 y throughout the core, a function of the intensity of hydrothermal inputs. Distinct hydrothermal events are recorded at 6,000 and 8,500 y B.P. in layers containing >90% vent-derived material. Vertical metal profiles and interelement relationships in the core result from variable deposition of oxides and sulfides, oxidation, and dissolution of sulfide phases and scavenging of metals from seawater.

Molinari, R.L., and K.D. Leaman. Variability of Gulf Stream surface currents in the Straits of Florida. Mariners Weather Log, 31(3):10-13 (1988).

No abstract.

Molinari, R.L., and J. Morrison. The separation of the Yucatan Current from the Campeche Bank and the intrusion of the Loop Current into the Gulf of Mexico. Journal of Geophysical Research, 93(C9):10,645-10,654 (1988).

Data collected in the eastern Gulf of Mexico during 1974, 1975, and 1976 show that the penetration of the Loop Current into the Gulf is strongly correlated with the location of the Yucatan Current on the Campeche Bank. The Loop does not penetrate far into the Gulf when the Yucatan Current separates from the bank in the vicinity of the Catoche Tongue (i.e., the eastern Campeche Bank). Deep Loop penetrations are correlated with separations farther west on the bank. The angle of the Yucatan Current at separation is also correlated with separations farther west on the bank. The angle of the Yucatan Current at separation is also correlated with the location of separation (i.e., smaller angles relative to due east are correlated with separations from farther east on the bank). Thus, small angles at separation are correlated with shallow intrusions of the Loop. Historical temperature data collected in the eastern Gulf are reviewed and support these correlations. Simple conservation of potential vorticity considerations can explain the correlation between the angle at separation and the penetration of the Loop.

Palmer, D.R., M.G. Brown, F.D. Tappert, and H.F. Bezdek. Classical chaos in nonseparable wave propagation problems. Geophysical Research Letters, 15(6):569-572 (1988).

Numerical calculations show that acoustic ray paths in a weakly range-dependent, deterministic ocean model exhibit chaotic behavior, that is, have an exponentially sensitive dependence on initial conditions. Since the ray equations define a nonautonomous Hamiltonian system with one degree of freedom, these results may be understood in terms of recent advances in classical chaos. The Hamiltonian structure of ray equations in general suggests that chaotic ray trajectories will be present in all types of linear wave motion in geophysics when variables do not separate, as in laterally inhomogeneous media.

Palmer, D.R., L.M. Lawson, Y.-H. Daneshzadeh, and D.W. Behringer. Computational studies of the effect of an El Niño/Southern Oscillation event on underwater sound propagation. In Computational Acoustics: Algorithms and Applications, D. Lee, R.L. Sternberg, and M.H. Schultz (eds.). Elsevier Science Publishers B.V. (North-Holland), Amsterdam, 335-356 (1988).

Computer simulations of underwater sound propagation in the equatorial Pacific have been undertaken using a recently-developed program called ULETA. This program was developed to exploit the characteristics of modern computing systems including the clustering of processors, command languages that permit interactive processor communication, and the availability of color graphics hardware and software. It has three modes of operation: a ray-tracing mode; a continuous-wave mode in which transmission loss as a function of depth and range is obtained for a source radiating a single acoustic frequency; and a pulsed mode in which the pressure resulting from a pulsed source is obtained at selected locations as a function of time. The input data for the simulations consisted of a series of sound-speed profiles which reflect the onset, evolution, and cessation of the most recent El Niño/Southern Oscillation (ENSO) event. The results of the computations indicate the presence of a layer of ray-path instability in the ocean, extending from about 50 m to 280 m in depth, which suddenly became very quiet during the ENSO event. Sound which entered this layer or was generated within it could not have traveled on for more than a few tens of kilometers in range without striking the bottom and experiencing the usual severe losses in intensity. While the existence of this layer provides an opportunity to monitor ENSO events using underwater sound, it prevents the straightforward application of the techniques of acoustic tomography to study the dynamics of the ocean in the layer. This is unfortunate since the major temperature anomalies occur within it.

Pazos, M.C. Drifting buoy data from the equatorial Pacific for the period January 1, 1984 through May 31, 1985. NOAA Data Report, ERL AOML-11 (PB88-212824), 100 pp. (1988).

No abstract.

Powell, M.D. Boundary-layer structure and dynamics in outer hurricane rainbands. Ph.D. thesis, Florida State University, Tallahassee, 227 pp. (1988).

Results of hurricane boundary-layer experiments conducted in outer rainbands of Hurricanes Josephine (1984) and Earl (1986) are presented. Comparisons of precipitation, kinematic, and thermodynamic structures in these storms indicate that principal rainbands have common characteristic mesoscale and convective-scale features in the boundary layer. The two-dimensional mesoscale structure suggests that rainbands are made of a linear aggregate of cellular reflectivity elements (on the inner, upshear side of the band) and stratiform rain (on the outer downshear side). The band is oriented perpendicular to the shear above the boundary layer and cells move downband at about 80% of the maximum wind. Alongband and crossband wind and equivalent potential temperature maxima are located on the outer side of the band axis. Updrafts and downdrafts are preferentially located on the inner side of the band axis. Downdraft transport of cool and dry air from middle levels on the inner side of the rainband was responsible for modifying mixed-layer structure adjacent to the band on alongband scales of 100 km. An undisturbed mixed layer of 500 m was present on the outer side of the band. Application of a mixed-layer model to low-level flow trajectories from the outer rainband to the eyewall indicates that under some conditions, the mixed layer may not recover sufficiently and low surface equivalent potential temperature air may reach the eyewall. These conditions are associated with suppressed flow in a region of positive divergence with moderate rainfall from a middle level anvil cloud. Differential evaporation cooling over the transition layer drives entrainment of dry air, resulting in a drier mixed layer (with lower surface equivalent potential temperature). The model results suggest that incomplete recovery may be responsible for transitional changes in hurricane intensity.

Rona, P.A. Hydrothermal mineralization at oceanic ridges. Canadian Mineralogist, 26:431-465 (1988).

A compilation of over 100 mineral occurrences at oceanic ridges and rifts comprising the global seafloor spreading center system has been made in terms of host-rock lithology (volcanic- or sediment-hosted) and of stage (early, advanced) and rate (slow-, intermediate- to fast-spreading) of opening of ocean basin. At this early phase of exploration when less than 1% of the ~55,000 km global length of spreading centers has been systematically explored, examples of almost all major varieties of volcanic- and sediment-hosted hydrothermal deposits associated with basaltic rocks in the geologic record have been found at present spreading centers. Review of this global data base indicates that a range of hydrothermal mineral-deposit sizes from small to large (>1 x 106 tonnes) occurs at all seafloor spreading rates. Based on available data, however, larger deposits (but fewer per unit length of spreading axis) form at slow- rather than at intermediate- to fast-spreading centers. Larger deposits are more common in sediment-hosted than in volcanic-hosted settings regardless of spreading rate. A spectrum of hydrothermal deposit varieties (stratiform, stockwork and disseminated sulfides; various forms of sulfate, carbonate, silicate, oxide and hydroxide deposits) occurs in almost all of the tectonic settings. High-intensity, ore-forming, subseafloor, hydrothermal convection systems that conserve heat and mass, and concentrate hydrothermal precipitates, are extremely localized by anomalous physical and chemical conditions relative to nearly ubiquitous low-intensity hydrothermal activity at, and flanking, seafloor spreading axes at all spreading rates. Two distinct shapes of volcanic-hosted hydrothermal deposits at seafloor spreading centers and in the geologic record may be explained by differences in fluid dynamic behavior controlled by temperature-salinity properties of solutions. Massive sulfide deposits that are mound-shaped in profile are constructed by hydrothermal solutions that discharge as buoyant plumes; examples are the TAG massive sulfide mound forming on the Mid-Atlantic Ridge, and the Archean Noranda-area deposits. Massive sulfide deposits that are saucer- or bowl-shaped in profile are formed by ponded solutions denser than surrounding seawater; examples are the Atlantis II Deep deposits of the Red Sea, and the Cretaceous Troodos deposits of Cyprus. Review of an existing data set on 508 massive sulfide deposits in the geologic record indicates that fewer volcanic-and sediment-hosted massive sulfide deposits are associated with basaltic rocks than with rhyolitic rocks (<26% versus 56%, respectively). This observation suggests that seafloor spreading centers have been significant as tectonic settings for massive sulfide formation through geologic time, although subsidiary to continental rifts and volcanic island arcs.

Rona, P.A. Book review: "The geology of North America: The western North Atlantic region." Economic Geology, 83:666-667 (1988).

No abstract.

Shapiro, L.J., D.E. Stevens, and P.E. Ciesielski. A comparison of observed and model-derived structures of Caribbean easterly waves. Monthly Weather Review, 116(4):921-938 (1988).

A linear primitive equation model has been used to test the hypothesis that the vertical structure of observed Caribbean easterly waves is determined by the interaction between convective heating and the environmental wind. The model determines the response to a propagating heat source in a specified basic state. The model allows for the inclusion of diffusion and cumulus momentum transports. The linear perturbations are assumed to have the form of a single Fourier component in the zonal direction. The frequency and zonal wavelength of the disturbance are taken from observations of the three-dimensional structure of a series of Caribbean easterly waves made by Shapiro. The structure of the basic state zonal wind, assumed to be a function of height, is based on observations near the latitude of largest observed wave amplitude. The maximum heating rate is 5 K day^-1, centered at about 19°N. Very good agreement is found between the model-derived vertical structure of the waves and that observed by Shapiro (1986). In particular, the observed 90° westward phase shift between the 200 mb and near-surface troughs, and the westward tilt of the trough axis with height, are reproduced in the model solutions. Although linearization is not strictly valid for the observed wind amplitudes of 5 m s^-1, the model's linear dynamical framework appears to represent the wave's structure well. The westward phase shift is found to depend on the downward flux of wave energy toward a near-critical layer near the ground. Experiments also suggest that the latitude of the disturbance may be as important a factor in the determination of the westward tilt of the trough axis as is the structure of the basic state zonal wind. An eastward tilt of the trough axis in the lower troposphere, such as that in the classical model of a Caribbean easterly wave, can occur at low latitudes, when the westward phase shift is in a narrow layer near the level of maximum heating. Cumulus momentum transports do not substantially change the structure of the forced wave disturbance. The model solutions are compared with similar experiments of Holton, and are related to results of Stevens, Lindzen and Shapiro.

Thacker, W.C. A cost-function approach to the assimilation of asynoptic data. Journal of Scientific Computing, 2(2):137-158 (1988).

This paper describes a method for reconstructing a synoptic state by fitting dynamics to asynoptic data. The best fit is defined by the minimum of a quadratic cost function, and dynamics are enforced through the use of a penalty term. When the coefficient of the penalty term is identified as the inverse of the variance of model error, the method yields the same results as Kalman filtering, and in the limit of infinitely large coefficients, the same as strong-constraint formalisms. The self-adjoint nature of the equations for the best fit motivated the use of a relaxation method for their solution. The method is illustrated within the context of one-dimensional, linear, shallow-water wave dynamics, where computational examples indicate that a synoptic state is properly determined only if the asynoptic data are equivalent to complete initial conditions.

Thacker, W.C. Fitting models to inadequate data by enforcing spatial and temporal smoothness. Journal of Geophysical Research, 93(C9):10,655-10,665 (1988).

When observations are too sparse to determine the state of a dynamical model, it is necessary to make use of prior knowledge or prejudice. The approach discussed here is to require that the model state be the best smooth fit to the sparse data. The requirement of smoothness is enforced by introducing bogus data, which correspond to hypothetical observations that properties such as slope, curvature, or temporal tendency of model fields have zero values within some specified accuracy. The bogus data serve to increase the effective ratio of data to model degrees of freedom. The concept of bogus data allows a bias toward smoothness to be incorporated easily into the adjoint method for fitting time-dependent models to asynoptic data. Computational examples using a simple three-wave model show that reasonable fits can be obtained even when the number of real data is considerably less than the number of model degrees of freedom.

Thacker, W.C., and R.B. Long. Fitting dynamics to data. Journal of Geophysical Research, 93(C2):1227-1240 (1988).

A formalism is presented for fitting dynamic forecast models to asynoptic data. Because of the importance of wind stress forcing in oceanic models and of the inadequacies of wind stress observations, the formalism allows an oceanic model to be fit to both oceanographic and meteorological data. Within the context of this formalism the important question of whether an asynoptic data set contains sufficient information to determine the model state completely and unambiguously is discussed. Becuse the information travels along wave characteristics, it is clear that for the data to be sufficient to determine the model state, they must be distributed so that every feature of the flow is seen at some time or another. Such widespread coverage of the oceans requires a data collection system that relies heavily on satellites. The formalism is illustrated using a highly truncated model of the wind-driven equatorial ocean and computational examples demonstrate how surface elevation and wind stress observations might be used to recover the model state.

Thayer, V.G., S.B. Reilly, P.C. Fiedler, C.W. Oliver, and D.W. Behringer. Report of ecosystem studies conducted during the 1987 eastern tropical Pacific dolphin survey on the research vessel McArthur. NOAA Technical Memorandum, NMFS SWFC-114 (PB88-238795), 120 pp. (1988).

No abstract.

Thayer, V.G., B.G. McDonald, J.M. Ellingson, C.W. Oliver, D.W. Behringer, and S.B. Reilly. Report of ecosystem studies conducted during the 1986 eastern tropical Pacific dolphin survey on the research vessel McArthur. NOAA Technical Memorandum, NMFS SWFC-104 (PB88-215199), 120 pp. (1988).

The primary objective of the dolphin habitat monitoring portion of the program is to provide information about the effects of large-scale environmental variation on the estimates of trends in dolphin abundance. The authors are monitoring these environmental effects by examining relationships between dolphin distribution and oceanographic patterns and processes. They sample these phenomena, concurrently with the dolphin sighting census, by measuring the regional and local changes in such environmental parameters as chlorophyll, nutrients, temperature, salinity, oxygen, and the occurrence of seabirds and other animals.

Thayer, V.G., R.L. Pitman, K.A. Rittmaster, G.G. Thomas, D.W. Behringer, and S.B. Reilly. Report of ecosystem studies conducted during the 1986 eastern tropical Pacific dolphin survey on the research vessel David Starr Jordan. NOAA Technical Memorandum, NMFS SWFC-105 (PB88-214630), 114 pp. (1988).

The National Marine Fisheries Service is responsible for assessing the status of dolphin stocks affected by the tuna purse seine fishery in the eastern tropical Pacific. The primary objective of the dolphin habitat monitoring portion of the program is to provide information about effects of large-scale environmental variation on estimates of trends in dolphin abundance. This report describes types sampling techniques and the types of data collected. It also reports regional and local changes in environmental parameters such as chlorophyll, nutrients, temperature, salinity, oxygen, and the occurrence of seabirds and other animals occurring concurrently with dolphin sightings.

Thayer, V.G., S.B. Reilly, P.C. Fiedler, R.L. Pitman, G.G. Thomas, and D.W. Behringer. Report of ecosystem studies conducted during the 1987 eastern tropical Pacific dolphin survey on the research vessel David Starr Jordan. NOAA Technical Memorandum, NMFS SWFC-115 (PB88-236690), 100 pp. (1988).

No abstract.

Thompson, G., S.E. Humphris, B. Schroeder, M. Sulanowska, and P.A. Rona. Active vents and massive sulfides at 26�N (TAG) and 23�N (Snakepit) on the Mid-Atlantic Ridge. Canadian Mineralogist, 26:697-711 (1988).

Two active hydrothermal vent sites on the Mid-Atlantic Ridge at 26�N (TAG) and 23�N (Snakepit) have recently been discovered at depths of 3,700 and 3,500 m, respectively. Although black smokers are present at both sites, their geological settings differ. The TAG area is located on older sedimented crust a few kilometers from the spreading axis, at the junction of the rift-valley floor and the east wall; the Snakepit site is atop a large volcanic ridge (40 km long, up to 600 m high) in the axial zone of the rift valley. The TAG site is the larger of the two and is probably older. Hydrothermal discharge from vents at both sites ranges from shimmering water, through white smokers (226�C) to black smokers (335�C and 350�C). Hydrothermal solutions are similar in major-element composition to those from the East Pacific Rise. Mineralization is similar to that occurring on faster-spreading ridges, e.g., the dominant polymetallic sulfides are pyrite, pyrrhotite, chalcopyrite and sphalerite; anhydrite is the main sulfate phase. The deposits differ from some of these on the East Pacific and Juan de Fuca ridges in having little or no barite, very little amorphous silica, and in having abundant aragonite as a late-stage precipitate. Diagenesis and weathering, particularly at the TAG site, have produced abundant amorphous iron oxides and hydroxyoxides, goethite, hematite, atacamite, jarosite, and sulfur. At the Snakepit site the black smokers consist mainly of pyrrhotite, but this sulfide phase is absent from the active chimneys at TAG. Zinc sulfide occurs as the predominant phase in the lower-temperature white smokers at both sites.

Van Dover, C.L., B. Fry, J.F. Grassle, S. Humphris, and P.A. Rona. Feeding biology of the shrimp Rimicaris exoculata at hydrothermal vents on the Mid-Atlantic Ridge. Marine Biology, 98(2):209-216 (1988).

A newly described species of shrimp, Rimicaris exoculata, Williams and Rona (1986), dominates the megafaunal community at two hydrothermal vent sites on the Mid-Atlantic Ridge. Behavioral observations and gut-content analyses indicate that these shrimp ingest large amounts of sulfide particles from black smoker chimneys. No evidence was found for chemoautotrophic endosymbionts in R. exoculata, based on analyses of morphology, stable isotopes, lipopolysaccharides, and ribulose-1,5-bisphosphate carboxylase activity. High bacterial productivity is required to sustain populations of R. exoculata at these vent sites.

Wilburn, A.M., E. Johns, and M.H. Bushnell. Current velocity and hydrographic observations in the southwestern North Atlantic Ocean: Subtropical Atlantic Climate Study (STACS), 1987. NOAA Data Report, ERL AOML-12 (PB89-114011), 92 pp. (1988).

The main objectives of the Subtropical Atlantic Climate Studies (STACS) program are to increase understanding of the dynamics of the North Atlantic circulation and the role of ocean circulation in global climate, to develop the capability to monitor the climatically important processes, and to develop coupled ocean atmosphere general circulation models. The report provides data on the observational studies of western boundary currents, extending the study area southward to Brazil (4°N) in order to examine the contribution of cross-equatorial boundary currents to the North Atlantic mass and heat fluxes. Pegasus and CTD data are given for various sections.

Willis, P.T., and A.J. Heymsfield. Melting-layer structure in MCC stratiform precipitation. Preprints, 10th International Cloud Physics Conference, Bad Homburg, Federal Republic of Germany, August 15-20, 1988. American Meteorological Society, Boston, 699-701 (1988).

No abstract.

Willoughby, H.E. Linear motion of a shallow-water, barotropic vortex. Journal of the Atmospheric Sciences, 45(13):1906-1928 (1988).

A shallow-water barotropic model of tropical cyclone motion allows calculation of linear wavenumber one perturbations on a maintained, moving axisymmetric vortex. The perturbations are Rossby waves that depend upon the radial gradient of axisymmetric relative vorticity rather than the meridional gradient of absolute vorticity. Although the motion of the vortex is a parameter for calculation of the perturbations, the motion in a particular situation is determinate because it minimizes the Lagrangian of the system. The motion in an environmental current matches the current, except at frequencies where the vortex is barotropically unstable. Imposed sources and sinks of mass simulate the effects of convection. The "convectively-induced" motions excite the barotropic instability plus a mode that depends upon forcing at the Rossby wave critical radius. This mode has largest amplitude and fastest vortex motion at the orbital frequency of the axisymmetric flow where forcing is imposed. It seems to correspond with the trochoidal motion of real tropical cyclones. For cyclonic frequencies only, perturbation in the stream-function field resembles a solitary Rossby wave and exhibits counterrotating gyres isolated from the relative flow due to the vortex motion. The vortex motion on a beta plane is largely meridional with speed proportional to the total relative angular momentum of the vortex. When the vortex has cyclonic circulation throughout, the northward motion is much too fast. This unreasonable result highlights the importance of nonlinear processes in tropical cyclone motion.

Willoughby, H.E. The dynamics of the tropical cyclone core. Australian Meteorological Magazine, 36(3):183-191 (1988).

The core of a tropical cyclone occupies the inner 100-200 km of the vortex. It is dominated by a cyclonic primary circulation in balance with a nearly axisymmetric, warm core low-pressure anomaly. Superimposed on the primary circulation are weaker asymmetric motions and an axisymmetric secondary circulation. The asymmetries, which may be either internal gravity waves or Rossby waves, modulate precipitation and cloud into trailing spirals. The axisymmetric secondary circulation, driven by latent heat release and surface friction, comprises the following parts: surface inflow that extracts latent heat from the sea and replaces the frictional loss of angular momemtum (M) to the sea; diabatically forced deep inflow that supplies an excess of M above frictional loss; the eyewall, an outward sloping locus of convective ascent; diabatically forced descent inside the eye; and upper tropospheric inflow. The eyewall usually moves inward as a result of differential adiabatic heating across the wind maximum. Eyewall succession occurs in intense cyclones when two concentric eyewalls are present and the outer replaces the inner. Because of their semibalanced dynamics, the primary and secondary circulations are relatively simple and well understood. These dynamics are not valid in the upper troposphere where the outflow is comparable to the swirling flow, nor do they apply to the asymmetric motions. Since the synoptic-scale environment appears to interact with the vortex core in the upper troposphere by means of the asymmetric motions, future research should emphasize this aspect of the tropical-cyclone dynamics.

Wilson, W.D., and A. Leetmaa. Acoustic Doppler current profiling in the equatorial Pacific in 1984. Journal of Geophysical Research, 93(C11):13,947-13,966 (1988).

Hydrographic data and acoustic Doppler current profiles collected from 150°W to 85°W in the equatorial Pacific during 1984 showed significant seasonal changes in the temperature and velocity fields. On the equator, the surface current was eastward in April up to 80 cm s^-1, reversing to westward at 100 cm s^-1 by November. Over the same period, the Equatorial Undercurrent (EUC) transport decreased, the equatorial zonal pressure gradient (ZPG) increased, and the depth of the mixed layer and EUC core deepened. Off the equator at 150°W, the North Equatorial Countercurrent (NECC) was absent in April/May but pronounced in October/November. Superimposed on this seasonal variability were smaller-scale (roughly 1,000 km wavelength) correlated fluctuations in the upper ocean temperature and velocity fields. We identify these structures with the 20- to 30-day instability waves (Legeckis, 1977). The coincident high-resolution velocity and temperature data allowed the calculation of Reynold's stresses due to the waves and resultant heat and momentum flux estimates as well as details of the vertical phase structure. Barotropic instability at the northern edge of the EUC is a likely source of energy for these waves. Estimated EUC transport decreased from 50 in April to 25 × 10⁶ m³ s^-1 in November while the westward wind stress doubled and the 0-/400-dbar ZPG quadrupled. The data were used to estimate terms in the momentum balance in the upper 150 m, and it was found that nonlinear terms were often at least as important as the integrated ZPG in balancing the surface wind stress. East of 120°W, the eastward advection of eastward momentum, UU_x, was particularly important. These momentum equation terms were used to estimate a profile of the coefficient of vertical eddy viscosity; it was similar to profiles estimated by bulk methods and by parameterization by Richardson number. **1987**

Atwood, D.K., H.H. Cummings, W.J. Nodal, and R. Caballero-Culbertson. The CARIPOL Petroleum Pollution Monitoring Project and the CARIPOL petroleum pollution database. Caribbean Journal of Science, 23(1):1-4 (1987).

In 1976, an IOC/FAO/UNEP workshopon Marine Pollution Monitoring in the Caribbean and Adjacent Regions established petroleum to be the priority pollutant of concern to the region. In 1979, IOCARIBE established the CARIPOL Marine Pollution Research and Monitoring Program and defined, as its first project, the monitoring of petroleum pollution in terms of three parameters, i.e., tar on beaches, floating tar, and dissolved/dispersed petroleum hydrocarbons. In 1980, IOCARIBE conducted workshops in English and Spanish to train participants from regional governments in the methodology necessary to measure these parameters and published a manual for use by these participants in both languages. Since that time, participants from various governments in the region have made close to 8,000 observations and have reported them to a central data center. This data is stored in a computer and can be accessed by a data management system. It is available to regional scientists for use in assessing the stage of petroleum pollution in the region. This symposium is designed to report progress on this effort, both on an individual government and regional basis.

Atwood, D.K., S. Dinkel-McKay, G.C. Romero, and E. Van Vleet. Floating tar and dissolved/dispersed petroleum hydrocarbons in the northern Gulf of Mexico and the Straits of Florida. Caribbean Journal of Science, 23(1):73-76 (1987).

As part of the IOCARIBE/CARIPOL Petroleum Pollution Monitoring Project, the United States has made 393 measurements of floating tar and 114 measurements of dissolved/dispersed petroleum hydrocarbons (DDPH) using CARIPOL described procedures. The majority of these were made in the northern and eastern Gulf of Mexico and the Straits of Florida. Results indicate that DDPH and floating tar covary in the study area and that the highest levels of contamination exist in the southern Straits of Florida between Cuba and the Florida Keys. The lowest levels were found on the western Florida Shelf and in the northern Straits of Florida between southeast Florida and the Bahamas. These results are consistent with beach tar studies along the coast of Florida which show that western and northeastern Florida beaches are quite pristine, whereas beaches on the windward (southeast) side of the Florida Keys are heavily oiled. Intermediate levels of contamination were found in the northern Gulf of Mexico and the Gulf Loop Intrusion waters which would indicate that beaches along the northern Gulf coast should have average tar contamination levels of roughly 1-20 grams per square meter as compared to 20-80 grams per square meter in the Florida Keys.

Atwood, D.K., F.J. Burton, J.E. Corredor, G.R. Harvey, A.J. Mata-Jimenez, A. Vasquez-Botello, and B.A. Wade. Petroluem pollution in the Caribbean. Oceanus, 30(4):25-32 (1987).

The Intergovernmental Oceanographic Commission (IOC) worked cooperatively with a Steering Committee of regional scientists to design a program that would (1) provide necessary information, and (2) allow laboratories from throughout the region to participate without expensive, sophisticated equipment to determine the severity of the petroleum pollution problem and monitor its effects. UNEP provided funds to train participants, and for symposia to present, discuss, and publish the results. The program was named CARIPOL, for CARIbbean POLlution research and monitoring, and the Steering Committee designed a program to monitor three parameters related to petroleum pollution: (1) tar on beaches; (2) floating tar; and (3) dissolved/dispersed petroleum hydrocarbons (DDPH). During the following six years, CARIPOL participants provided data on more than 9,000 observations throughout the region. A significant level of petroleum pollution exists throughout the wider Caribbean. Manifestations of this pollution include serious tar contamination of windward exposed beaches, high levels of floating tar within the major currents system, and very high levels of dissolved/dispersed hydrocarbons in surface waters. The sources of petroleum pollution in the region include oil entering from the adjacent North Atlantic (50%) and tanker ballast washings (50%). Effects of this petroleum pollution include: (1) tar levels on many beaches that either prevent recreational use, or require expensive clean-up operations; (2) probable distress and death to marine organisms, such as endangered turtles who feed on floating tar; and (3) responses in the enzyme systems of marine organisms that have been correlated with declines in reproductive success.

Atwood, D.K., F.J. Burton, J.E. Corredor, G.R. Harvey, A.J. Mata-Jimenez, A. Vasquez-Botello, and B.A. Wade. Results of the CARIPOL petroleum pollution monitoring project in the wider Caribbean. Marine Pollution Bulletin, 18(10):540-548 (1987).

Since 1979, about 9000 data points for tar on beaches, floating tar, and dissolved/dispersed petroleum hydrocarbons have been collected by 14 governments in the Caribbean-Gulf of Mexico region. Analysis of these data has allowed an assessment as to the status of petroleum pollution in the region. Tar levels on windward exposed beaches are very high and impact tourist use of them. Data also indicate that dissolved/dispersed hydrocarbons in the Gulf of Mexico are much higher than that measured by 1975-1980 MAPMOPP study in "clean" areas of the World's oceans. Indications are that about half of the tar in the region enters by way of the prevailing current and wind regime from the North Atlantic gyre system. The remaining half comes mostly from tanker cleaning and ballast discharge in the region.

Baker, E.T., G.J. Massoth, R.W. Collier, J.H. Trefry, D. Kadko, T.A. Nelsen, P.A. Rona, and J.E. Lupton. Evidence for high-temperature hydrothermal venting on the Gorda Ridge, northeast Pacific Ocean. Deep-Sea Research, 34(8A):1461-1476 (1987).

The first water-column survey of the axial valley of the Gorda Ridge, a slow- to medium-rate spreading center within 300 km of the coast of Oregon and California, found strong evidence for ongoing hydrothermal venting. At the northern end of the ridge, anomalously high concentrations of helium-3, dissolved manganese, particulate iron, and methane confirmed the hydrothermal origin of the above-bottom plumes identifiable as maxima in light-attenuation profiles. The presence of excess radon-222 and the highly soluble hydrothermal precipitate anhydrite in the plumes require a local vent source; the precipitation of anhydrite requires fluid temperatures of at least 130°C. Indications of hydrothermal activity elsewhere in the axial valley were inconclusive.

Barnes, G.M., G.J. Stossmeister, M.A. LeMone, and J.F. Gamache. A rainband on the trailing side of a fast-moving hurricane. Preprints, 17th Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 7-10, 1987. American Meteorological Society, Boston, 377-380 (1987).

No abstract.

Black, M.L., and R.W. Burpee. Temporal and spatial variations of precipitation near the center of tropical cyclones. Preprints, 17th Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 7-10, 1987. American Meteorological Society, Boston, 170-173 (1987).

No abstract.

Black, P.G., and F.D. Marks. Environmental interactions associated with hurricane supercells. Preprints, 17th Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 7-10, 1987. American Meteorological Society, Boston, 416-419 (1987).

No abstract.

Bluestein, H.B., and F.D. Marks. A note on the structure of the eyewall of Hurricane Diana (1984): Comparison of radar and visual characteristics. Monthly Weather Review, 115(10):2542-2552 (1987).

Features seen in aerial and satellite photographs of the inside edge of the eyewall of Hurricane Diana (1984) are compared with features seen in digitized three-dimensional airborne radar reflectivity data. The photographs show regularly spaced, upwind (downshear) tilted striations in the northeast, east, and southeast sectors of the eyewall that are nearly collocated with upwind (downshear) tilted axes of relative reflectivity maxima of approximately 15 dBZ.

Broecker, W.S., and T.-H. Peng. The oceanic salt pump: Does it contribute to the glacial-interglacial difference in atmospheric CO₂ content? Global Biogeochemical Cycles, 1(3):251-259 (1987).

Sea ice formation drives salt from the surface to the deep sea. In so doing, it lowers the salinity of polar surface waters. We show here that this reduction in turn lowers the CO₂ partial pressure of polar surface waters and hence also of the atmosphere. We propose that during glacial time when more sea ice existed, this pumping action may have been stronger. If so, part of the glacial to interglacial atmospheric CO₂ content change observed in ice cores may have been driven by the ocean's salt pump.

Broecker, W.S., and T.-H. Peng. The role of CaCO₃ compensation in the glacial to interglacial atmospheric CO₂ change. Global Biogeochemical Cycles, 1(1):15-29 (1987).

The only viable explanations put forth to date for the glacial to interglacial change in atmospheric CO₂ content suggested from measurements of the CO₂ content of gas extracted from ice cores involve changes in the ocean's nutrient cycles. Any nutrient change capable of creating the 80 µatm changes in atmosphere CO₂ pressure suggested by the ice core results also creates significant change in the deep ocean's CO₃⁼ content. Evidence from deep sea sediments suggests that these CO₃⁼ changes are compensated on the time scale of a few thousand years by reductions or increases in the amount of CO₃⁼ accumulating in deep sea sediments. This compensation process has two important consequences. First, it significantly increases the magnitude of the CO₂ change per unit of nutrient forcing. Second, it causes a delay in the response of the atmospheric CO₂ change. While the first of these consequences is a boon to those seeking to explain the CO₂ change, the second may prove to be a curse. The ice core CO₂ record shows no evidence of a significant lag between the CO₂ response and the polar warming. In any case it is important that we improve our knowledge of the magnitude and timing of the CaCO₃ preservation events which mark the close of episodes of glaciation and of the dissolution events which mark the onset of these episodes.

Burpee, R.W., J. Ward, and D.G. Marks. A preliminary evaluation of Omega dropwindsonde data in track forecasts of hurricanes. Preprints, 17th Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 7-10, 1987. American Meteorological Society, Boston, 98-100 (1987).

No abstract.

Carsey, T.P. LISA: A new aerosol generation system for sampler evaluation. American Industrial Hygiene Association Journal, 48:710-717 (1987).

No abstract.

Carsey, T.P., S.A. Shulman, and C.D. Lorberau. An investigation of the performance of the 10-mm nylon cyclone. Applied Industrial Hygiene, 2:47-52 (1987).

No abstract.

Charlou, J.L., P.A. Rona, and J. Bougault. Methane anomalies over TAG hydrothermal field on Mid-Atlantic Ridge. Journal of Marine Research, 45(2):461-472 (1987).

Black smoker type hydrothermal venting was discovered in July 1985 at the TAG hydrothermal field in the rift valley of the Mid-Atlantic Ridge near 26°N. The authors present here, the first methane profiles in the seawater column over this black smoker along with methane profiles away from the black smokers for comparison. The CH₄ plume, spreading over 400 m above the seafloor, shows a maximum concentration of 105 nl/l at 3450 m (238 m above the bottom), correlated with a positive temperature anomaly (0.02°C). CH₄ concentrations up to 2,422 nl/l, correlated with a huge positive increase of in situ temperature (0.349°C), have been measured in samples taken 5 m above the seafloor, showing an important CH₄ input in this slow spreading site which is similar to inputs from fast spreading sites like the East Pacific Rise.

Chew, F., and M.H. Bushnell. Changing transport and curvature bias: A new type of meandering in the Florida Straits. Journal of Geophysical Research, 92(C9):9503-9513 (1987).

Meanders in strong, inertial flows are generally asymmetric. Florida Current meanders with periods of 7-10 days and flows that tend to meander offshore when strong and onshore when weak, which we call type A, have been widely documented. We find a countertrend in the Florida Current data collected under the aegis of Subtropical Atlantic Climate Studies: a type B meandering where flows tend to meander offshore when weak and onshore when strong. The tendency displays a largely one-sided preference for either the onshore or the offshore component of the meander. In particular, the data reveal a negative curvature bias during the generally higher transports in spring and summer when most of the speed cores were inshore, and a positive curvature bias during lower transports in fall and winter when most speed cores were offshore.

Ciesielski, P.E., L.J. Shapiro, and D.E. Stevens. A comparison of the observed and model-derived structures of tropical easterly waves. Preprints, 17th Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 7-10, 1987. American Meteorological Society, Boston, 249-252 (1987).

No abstract.

Clarke, T.L., and J.R. Proni. A pattern recognition approach to remote acoustic bottom characterization. In Progress in Underwater Acoustics, H.M. Merklinger (ed.). Plenum Press, New York, 225-229 (1987).

The possibility of extracting useful bottom information from reflected pulse waveforms at customary echo-sounding frequencies has been demonstrated experimentally. The one-dimensional nature of the sediment property continuum should also enable the use of remotely measured acoustical sedimentary properties to predict navigationally important mechanical characteristics. A convenient mathematical model has been developed to assess the effects of bottom roughness and material properties on bottom echo shape. The physical basis of the model is explained and model output is presented. The ability of this model to easily generate sample echoes from a wide range of bottom types permits a pattern recognition approach to be taken to the problem of extracting information from the ehco signals. An adaptive algorithm can be "trained" using model-generated echoes in the same way speech recognition systems are "trained." The linear discriminant algorithm can be trained to distinguish mud from gravel, but has difficulty with mud versus fine sand. A commercially available voice recognition system conversely has difficulty distinguishing sand from gravel. More sophisticated algorithms will be needed for general bottom discrimination.

Colin, C., and S.L. Garzoli. In-situ wind measurements and the ocean response in the equatorial Atlantic during the FOCAL/SEQUAL experiment. Journal of Geophysical Research-Oceans, 92(C4):3741-3750 (1987).

In-situ wind measurements collected as part of the Programme Francais Ocean et Climat dans l'Atlantique Equatorial (FOCAL)/Seasonal Response of the Equatorial Atlantic (SEQUAL) experiment (1983-1984) in the western and eastern parts of the equatorial Atlantic basin are described. They were obtained from meteorological stations placed at St. Peter and St. Paul Rocks (SPP) (1°N, 29°W) and at the top of a surface buoy moored in the Gulf of Guinea (0°N, 4°W). From the wind observations the wind stress was inferred, and results are compared with climatology. The seasonal variations of the temperature both at the surface and below the surface at 28°W and 4°W are interpreted in the light of the results of a nonlinear multilevel model in the cases of a sudden increase and a sudden relaxation of the trade winds.

Cornejo-Rodriguez, M.P., and D.B. Enfield. Propagation and forcing of high-frequency sea level variability along the west coast of South America. Journal of Geophysical Research, 92(C13):14,323-14,334 (1987).

Tide and wind data from coastal and island stations from Buenaventura, Colombia (4°N), to Callao, Peru (12°S), have been analyzed for the 1979-1984 time period to determine the propagation and forcing characteristics of coastal sea level variability at periods of days to weeks, as well as how they vary either with season or between the 1982-1983 El Niño-Southern Oscillation (ENSO) period and non-ENSO years. During four non-ENSO years, the ensemble averaged cross spectra between coastal sea level height (SLH) and local winds show weak evidence of local forcing during the whole year without significant differences between the austral summer and winter seasons, other than a greater energy in the wind fluctuations at Talara during summer. Cross spectra between SLH series from neighboring stations show evidence of poleward phase propagation during winter seasons at speeds of about 20 m s^-1 between La Libertad and Talara at periods of a week or more, and about 2.7 m s^-1 between Talara and Callao at periods of 5-11 days, but no propagation is found during summers. During the 1982-1983 ENSO there is a large increase in SLH energy at most frequencies at all coastal stations, but especially in the 8-11 day band, where energies are enhanced by as much as an order of magnitude above non-ENSO levels. The cross spectra between adjacent SLH stations indicate a nondispersive poleward propagation of events during the 1982-1983 ENSO with phase speeds of 2.2-3.5 m s^-1 from La Libertad to Talara (periods of a week or more) and 3.4-3.6 m s^-1 from Talara to Callao (3.5 days or more). As with the SLH energy, the coherence and phase propagation were much stronger along the Peru coast in 1982-1983 than during non-ENSO periods, especially in the 8-11 day band. The one-third increase in phase speeds during the ENSO over the non-ENSO speeds is found to be consistent with the anomalous depression of the density structure during El Niño. Comparisons between coastal SLH and the local alongshore wind suggest that locally forced SLH variability was obscured during the 1982-1983 ENSO by noncoastally forced, but energetic propagating fluctuations, which probably originated in the equatorial waveguide.

DeMaria, M. Tropical cyclone track prediction with a barotropic spectral model. Monthly Weather Review, 115(10):2346-2357 (1987).

A barotropic spectral model (BSM) is developed to investigate the possibility of forecasting tropical cyclone tracks with global, general circulation models. The model is governed by a barotropic vorticity equation in spherical coordinates which is solved with a spectral method with spherical harmonic basis functions. The model was run with a triangular truncation of 128 on half of the northern hemisphere (180°W-0°W), and was initialized using horizontal winds from the NMC analyses vertically averaged from 1000 to 100 mb. The storm circulation is represented by a specified axisymmetric vortex and the model was tested by making 30 track forecasts of Atlantic tropical cyclones (13 storms) which occurred from 1979 to 1984. The skill of the model was assessed by comparing the track forecasts to forecasts from a model based on climatology and persistence (CLIPER). The BSM has statistically significant skill for 24 and 36 h track forecasts and longer range of skill for forecasts of low-latitude storms. For low-latitude storms, the BSM had than the operational SANBAR and moveable fine mesh (MFM) models. The sensitivity of the model to the horizontal resolution is tested. These results suggest that track forecasts could be made with a global spectral model with a triangular truncation of about 96. It might then be feasible to make track forecasts with a global spectral model similar to the operational model at the European Centre for Medium Range Weather Forecasts which uses a triangular truncation of 106. The sensitivity of the model to the domain size and to the specification of the initial vortex is also investigated. These results show that when simple lateral boundary conditions are used, the track forecast errors rapidly increase when the model domain is made smaller than half of a hemisphere. These results also show that the track errors are very insensitive to the size of the vortex, provided that the vortex is not unrealistically large. When the shape of the vortex profile is changed to include an anticyclonic circulation at large radii, the track errors are smallest when the total angular momentum of the vortex is close to zero. The errors rapidly increase as the total angular momentum becomes negative. The effect of modifying the initial analyses so that the deep-layer mean wind in the storm region is consistent with the previous storm motion is also studied. The track errors show the most reduction when the analyses within a radius of about 1000 km of the norm am modified.

Dodge, P.P., M.L. Black, R.W. Burpee, and F.D. Marks. Time-lapse radar imagery from landfalling hurricanes. Preprints, 17th Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 7-10, 1987. American Meteorological Society, Boston, 166-169 (1987).

No abstract.

Donoso, M.C.I., B. Le Mehaute, and R.B. Long. Database of maximum sea states during hurricanes. Journal of Waterway, Port, Coastal and Ocean Engineering, 113(4):311-326 (1987).

A simple method is developed for calculating a database of maximum sea states at a given location in deep water under hurricane conditions. The long-term statistics of maximum sea states under hurricane conditions can then be estimated from this data base. The method is based on (1) A parameterized time- and space-dependent wind-wave model that allows the evaluation of the sea state at a given, fixed location as a function of hurricane parameters and the location of the site relative to the storm track; and (2) the historical record of hurricane parameters for storms that have passed within 100 nautical miles of the selected site.

Donoso, M.C.I., B. Le Mehaute, and R.B. Long. Long-term statistics of maximum sea states during hurricanes. Journal of Waterway, Port, Coastal and Ocean Engineering, 113(6):636-647 (1987).

A method is developed to estimate the statistics of the maximum sea states at a given location under hurricane conditions. The method is based on the statistics of hurricane parameters on record. The cumulative probability distributions for hurricane parameters are combined through a Monte Carlo simulation to generate a large number of synthetic hurricanes. Then using a parameterized wind-wave model, the maximum sea states are calculated at the selected location for each simulated event. The obtained values are grouped and ranked, and the cumulative probability distribution of sea state is defined.

Enfield, D.B. Progress in understanding El Niño. Endeavor, 11(4):197-204 (1987).

Prior to the work of Jacob Bjerknes, the El Niño phenomenon was regarded as an aperiodic climatic event confined to the Pacific coast of South America. Spurred by a growing consciousness of the oceans' role in global climate, there has been an explosion of El Niño research in the last two decades. El Niño is now recognized to be an integral part of a Pacific-wide ocean relaxation, with global climatic impacts and economically important ecological consequences. However, we are still groping for the final prize: the ultimate cause of this climate anomaly and the ability to reliably predict its onset and intensity.

Enfield, D.B. The intraseasonal oscillation in eastern Pacific sea levels: How is it forced? Journal of Physical Oceanography, 17(11):1860-1876 (1987).

Daily sea level and surface winds at eastern Pacific shore locations and equatorial islands, together with gridded five-day averages of 850 mb winds, have been analyzed for the 1979-84 period to determine how the 40-60 day intraseasonal oscillation of eastern Pacific sea levels is forced, as described by Spillane et al. for 1971-75. The oscillation was also present in 1980-84 from Callao, Peru, to San Francisco, with maximum energy near 52-57 days and band limits of 43 and 65 days. During 1980-84, there was no evidence for forcing of the large-scale oscillation in the eastern Pacific, although a local contribution of forcing was superimposed on the remote signal at the California stations. Interannual fluctuations in amplitude were evident in the sea level time series, consistent with those of the corresponding wind oscillation in the western equatorial Pacific. The oscillation was best developed in both variables in 1980-82 and became weak or nonexistent during the recovery phase of the 1982-83 El Niño, similar to a weakening that occurred following the 1972-73 episode, noted by Spillane et al. The sea level oscillations have the characteristics of lowest baroclinic mode Kelvin waves that are primarily forced by a similar, energetic oscillation in the winds in the western equatorial Pacific. During the 1980-82 period a significant component of the wind signal extended into the central Pacific and was associated with sea level propagation speeds of about 5 m/s, suggesting a more extensive forcing along the equatorial waveguide at that time. In 1982-84, when the oscillation was weak, the sea level propagation was about 3 m/s, consistent with the free propagation of lowest baroclinic mode Kelvin waves in the central Pacific.

Enfield, D.B., M.P. Cornejo-Rodriguez, R.L. Smith, and P.M. Newberger. The equatorial source of propagating variability along the Peru coast during the 1982-1983 El Niño. Journal of Geophysical Research, 92(C13):14,335-14,346 (1987).

Using data obtained from tide gauges in South America, current meters along the equator and the Peru coast, and an array of pressure gauges and inverted echo sounders within and around the Galapagos archipelago, we have analyzed the equatorial origin of coastal trapped waves observed by Cornejo-Rodriguez and Enfield (this issue) along the Peru coast during the intense 1982-1983 El Niño. The propagating fluctuations along the coast were much stronger at that time either before or after the El Niño, and the variability was not locally forced by coastal winds. We find that the coastal variability was also more energetic during previous El Niño occurrences. At periods of one to two weeks the meridional component of currents on the equator was up to an order of magnitude more energetic than the zonal fluctuations and was consistently associated with sea level that fluctuates antisymmetrically between hemispheres. At periods longer than two weeks the zonal velocity component was more energetic and the cross-equatorial sea level variability was symmetric. The meridional and zonal phase structures of cross spectra involving the currents and sea level established the one- to two-week equatorial fluctuations as mixed Rossby-gravity (Yanai) waves of low wave number with infinite phase speed (standing oscillations) in the middle of the band (10 days); the corresponding structures for longer periods were consistent with non-dispersive Kelvin waves. Frequency domain EOF modes of the sea level and current data established the mixed Rossby-gravity waves as the principal source of the strong trapped wave variability in the one- to two-week band along the Ecuador-Peru coast during the 1982-1983 El Niño episode.

Esbensen, S.K., L.J. Shapiro, and E.I. Tollerud. The consistent parameterization of the effects of cumulus clouds on the large-scale momentum and vorticity fields. Preprints, 17th Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 7-10, 1987. American Meteorological Society, Boston, 48-51 (1987).

No abstract.

Esbensen, S.K., L.J. Shapiro, and E.I. Tollerud. The consistent parameterization of the effects of cumulus clouds on the large-scale momentum and vorticity fields. Monthly Weather Review, 115(3):664-669 (1987).

A physical and mathematical framework for the mutually consistent parameterization of the effects of cumulus convection on the large-scale momentum and vorticity fields is proposed. The key to achieving consistency is the understanding that the vorticity dynamics of the clouds below the spatial resolution of a large-scale dynamical model may be neglected in the vorticity budget when the clouds are considered to be independent buoyant elements sharing a common large-scale environment. This simplified approach is used to obtain a consistent pair of large-scale momentum and vorticity equations based on Ooyama's theory of cumulus parameterization. The results focus attention on the need to obtain a better understanding of the detrainment process and the pressure interactions between the clouds and their environment.

Franklin, J.L. Reduction of errors in Omega dropwindsonde data through postprocessing. NOAA Technical Memorandum, ERL AOML-65 (PB87-173308), 22 pp. (1987).

The postprocessing of Omega dropwindsonde (ODW) data at the NOAA Hurricane Research Division (HRD) is described. The errors common to ODW data are illustrated with examples, and the improvements to ODW accuracy through postprocessing are estimated.

Franklin, J.L., K.V. Ooyama, and S.J. Lord. Two improvements in Omega windfinding techniques. Journal of Atmospheric and Oceanic Technology, 4(1):214-219 (1987).

A one-dimensional local spline smoothing technique is applied to Omega navigational signals for the purpose of windfinding. Wind profiles so produced depend largely on two parameters of the smoothing procedure: the nodal spacing, which determines the smallest resolvable scale, and a filtering wavelength, which produces the necessary smoothing of the phase data, and prevents representational distortion of any power from the unresolved scales. Phase "noise" from stationary test sondes is superimposed on synthetic Omega signals to compare wind profiles obtained with this new procedure with profiles computed using other techniques. It is shown that the effect of aircraft maneuvers on Omega wind accuracy is not completely removed by the normal practice of evaluating all phase derivatives at a common time. Additional improvements in accuracy of 2-3 m s^-1 can be obtained by a "rate-aiding" technique using aircraft navigational data.

Gamache, J.F. The bulk water budget of Hurricane Norbert (1984). Preprints, 17th Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 7-10, 1987. American Meteorological Society, Boston, 351-354 (1987).

No abstract.

Garzoli, S.L. Forced oscillations on the equatorial Atlantic basin during the Seasonal Response of the Equatorial Atlantic Program (1983-1984). Journal of Geophysical Research-Oceans, 92(C5): 5089-5100 (1987).

A subset of data from an array of eight inverted echo sounders and a meteorological station deployed and maintained for 15 months in the equatorial Atlantic as part of the Seasonal Response of the Equatorial Atlantic Program are analyzed to determine the variability of forced oscillations of the basin. The analysis is done to study both low- and high-frequency variability. The most significant oceanic oscillations in the inertial gravity band are centered at 5.2 and 3.5 days. From the study of their meridional structure it is concluded that those oscillations correspond to forced inertial gravity waves with meridional structures corresponding to the meridional numbers n=1 and n=3, respectively.

Garzoli, S.L., and A. Bianchi. Time-space variability of the local dynamics of the Malvinas-Brazil confluence as revealed by inverted echo sounders. Journal of Geophysical Research, 92(C2):1914-1922 (1987).

Two inverted echo sounders have been deployed for approximately eight months in the region of the confluence of western boundary currents in the South Atlantic (37°58.7'S, 51°56.4'W and 37°29.3'S, 53°49.3'W). The confluence of the subtropical Brazil Current with the sub-Antarctic Malvinas Current creates a strong, sharp thermohaline front. From the time series obtained with the sounders, two parameters are obtained and analyzed: dynamic height from the surface relative to 800 m and the position of the front. The time series of dynamic height indicates the presence of a cold intrusion during November, the southward extension of the Brazil Current and northward extension of the Malvinas Current during January, and a simulataneous warming of the area at both moored locations (0.04 dyn m/month) from March through June.

Goldenberg, S.B., S.D. Aberson, and R.E. Kohler. An updated, fine-grid version of the operational barotropic hurricane-track prediction model. Preprints, 17th Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 7-10, 1987. American Meteorological Society, Boston, 86-89 (1987).

No abstract.

Hanson, K., G.A. Maul, and W. McLeish. Precipitation and the lunar synodic cycle: Phase progression across the United States. Journal of Applied Meteorology, 26(10):1358-1362 (1987).

The question of whether there is significant variation in precipitation in the United States at the lunar synodic period (29.531 days) has been examined, based on daily precipitation data for the period 1900-1980. Our results confirm previous studies and indicate by a new method that there is statistically significant variation in precipitation at this lunar frequency. We also show for the first time that there is spatial progression over the United States in the phase of the lunar-precipitation relationship. During spring, a precipitation maximum occurs first when the moon is gibbous in the northwestern United States, progressively later during the lunar cycle in the Midwest and, finally, about the time of the new moon in the East. The recognition of spatial progression in phase raises questions about the reality of previously proposed global, lunar-precipitation mechanisms. We suggest, instead, the actual cause-effect relationship may involve the long-wave circulation of the atmosphere.

Harvey, G.R. A personal overview of oil in the marine environment. Caribbean Journal of Science, 23(1):5-10 (1987).

Any personal perspective of oil in the sea is certain to be controversial. Environmental scientists and other citizens concerned with the health of the oceans usually disagree with those working in the multifaceted international petroleum industry. However, one fact does seem clear to both sides of the oil-in-the-sea controversy: the single most important event that led to less operational petroleum being discharged into the sea was not any environmental concern. It was the 1974 oil embargo of the OPEC countries which catapulted the price of a barrel of crude oil up to a level at which it was too valuable to lose. There is probably less oil entering the sea from production and transportation in 1985 than there was 15 years ago. Even the global carbon dioxide monitoring network recorded the effects of the 1974 embargo. There was actually less carbon dioxide entering the atmosphere for a while because of reduced fuel burning. Major accidents have occurred, and we have learned a great deal from studying the physical, chemical, and biological effects of precipitously injecting massive quantities of oil into the sea. We have learned much more about the nature and frequency of occurrence of natural seeps. Although nothing can be done to prevent such occurrences, we now understand what the natural exposure level of marine organisms would be and what the natural burden of tar on beaches would probably be without human intervention. Though oil pollution of the sea is presently less than that of a decade ago, there is an urgent need to continue to monitor its presence because social, economic, or political reversals in any part of the world could change the situation in less than one year.

Jin, H.-L., H.E. Willoughby, and J.M. Piotrowicz. Modeled hurricane's structure and evolution by a nonhydrostatic thermo-convective hurricane model (no ice phase). Proceedings, 7th National Conference on Typhoons, Shanghai, China, November 4, 1985. Shanghai Typhoon Institute, 221-230 (1987).

By using an axisymmetric, nonhydrostatic, thermo-convective storm model the genesis/evolution processes of tropical storms were simulated. The simulated hurricane structure, particularly in the inner region of the modeled storm, is very similar to those observed. The eyewall is composed of continuously altering convective cloud cells and the radius of the eye core discontinuously varies with their life cycle and their substitution. Three contract simulations have shown that thermal convections act vigorously, thus an intense hurricane is developed as the sea surface temperature increases while convections delay beginning and proceed slowly. Thus a longer pregnant (genetic) period is needed for the storm formation as the upper tropical environment above 700 hPa dried.

Jones, R.W. A simulation of hurricane landfall with a numerical model featuring latent heating by the resolvable scales. Monthly Weather Review, 115(10):2279-2297 (1987).

A nested grid hurricane model is used to transport a strong vortex over a straight coastline at about 4 m s^-1. The track, at landfall, of the vortex is about 20 km to the left of a control simulation without land. Just before landfall, a 15 km amplitude trochoidal oscillation of the vortex track occurs. This amplitude is nearly double that of similar oscillations of the control simulation. About 10 h before landfall, a spiral rainband nearly surrounds the vortex at radii of about 135 km. This rainband has a weak secondary maximum in the tangential wind and is the model analog of the secondary eyewalls observed by Willoughby et al. in several hurricanes. The rainfall in spiral rainbands diminishes during the 7 h before landfall. However, rainfall in the inner core of the vortex is greater during landfall than in the control simulation. The greatest rainfall accumulation is to the right of the vortex. However, compared with the control simulation, rainfall is greater to the left and less to the right of the vortex. This may be the result of an increase of the relative radial inflow in the boundary layer in the left-front quadrant near landfall. To the extent which is possible, these characteristics of landfall are related to observations.

Komar, P.D., and D.B. Enfield. Short-term sea-level changes and coastal erosion. In Sea-Level Change and Coastal Evolution, D. Nummedahl, O.H. Pilkey, and J.D. Howard (eds.). Society of Economic Paleontologists and Mineralogists, SEPM Special Publication 41, 17-27 (1987).

Investigations of the role of sea level in producing coastal erosion have focused mainly on the long-term rise due to melting of glaciers and thermal expansion of seawater. There are additional shorter term changes in the local sea level produced by a variety of ocean processes. Variations in the coastal currents, for example, can alter the water level at the shoreline due to the geostrophic balance between the current and the offshore sea-surface slope. Other factors which may alter local sea level include changes in atmospheric pressure, winds blowing either in the longshore or cross-shore directions, and the occurrence of upwelling. Because the inclined continental shelf and slope act as a wave guide, the fluctuations often become trapped and propagate over longshore distances beyond where they are actually generated. In that many of these processes are typically seasonal, the responding sea level also has a pronounced seasonal cycle, but frequently there can be significant fluctuations at periodicities of several days to a few weeks. The magnitudes of such changes vary considerably with coastal location but are typically on the order of 10 to 30 cm, achieving a maximum of about 100 cm in the Bay of Bengal. The occurrence of an El Niño in the equatorial Pacific is known to have considerable impact on the erosion of the coasts of California and Oregon. This occurs because associated with an El Niño are shifts in the storm paths and a temporary rise in sea level. An El Niño is a breakdown of the normal equatorial wind and current patterns. This breakdown releases water which is normally set up in the western Pacific by the trade winds. The release creates a "wave" of sea-level rise, which first propagates eastward along the equator and then poleward along the eastern ocean margin. Such "waves" have been measured in the tide records of the western United States, amounting to some 20 to 60 cm and lasting for several months. Such transient sea-level changes have likely played an important role in coastal erosion.

Landsea, C.W. A quantitative comparison of two BASIN lidar images. UCLA Undergraduate Science Journal, 4:49-56 (1987).

No abstract.

Leaman, K.D., and R.L. Molinari. Topographic modification of the Florida Current by Little Bahama and Great Bahama Banks. Journal of Physical Oceanography, 17(10):1724-1736 (1987).

The effect of local topography in modifying the structure and variability of the Florida Current is examined using shipboard acoustic Doppler and Pegasus acoustic current profiler data. Pegasus absolute velocity data were obtained during 16 cruises in the Florida Current at 27°N as part of the Subtropical Atlantic Climate Studies (STACS) program. The ensemble average of all Pegasus velocity data shows that the effect of the constriction imposed on the mean Florida Current by Little Bahama Bank can be detected up to 30 km into the Straits of Florida. A simple model is proposed to explain how this effect can produce the subsurface maximum of northward flow commonly observed in the eastern Straits. Pegasus and acoustic Doppler data obtained during the March 1984 STACS cruise are used to describe the temporal and spatial variability of the flow. It is shown that intermittent southward flow can exist in a band 10-15 km wide off Little Bahama Bank; one such event was detected during this cruise. The Pegasus data suggest that these events are associated with meandering of the Florida Current. These results may explain earlier observations in satellite synthetic aperture radar images of small-scale vortices moving southward across the mouth of Northwest Providence Channel.

Leaman, K.D., R.L. Molinari, and P.S. Vertes. Structure and variability of the Florida Current at 27°N: April 1982-July 1984. Journal of Physical Oceanography, 17(5):565-583 (1987).

Results of a two-year field experiment as part of the Subtropical Atlantic Climate Studies (STACS) program in the Straits of Florida are presented. Temperature and absolute ocean current observations were obtained by Pegasus acoustic current profilers over 16 cruises during which repeated cross sections of the Florida Current were made at 27°N. Results are shown for the mean velocity and temperature fields, the perturbation horizontal kinetic energy and potential energy fields and for those energy conversion terms that could be computed directly from the data. The barotropic and baroclinic energy conversion terms, although small, indicate that the flow is stable for both types of perturbations. A large part of the variability is contributed by short time scales (one week or less). The average and standard deviation of northward volume transport by the Florida Current during these cruises was (31.7 ± 3.0) × 10⁶ m³ s^-1. Barotropic and baroclinic contributions to the total heat flux across the North Atlantic Ocean at 27°N are computed for each cruise and for the two-year average of all cruises. With the use of previous estimates of the midbasin baroclinic and Ekman heat fluxes, the total average northward heat flux from the obsersvations is (1.29 ± 0.21) × 10¹⁵ W. To compare STACS data with results from a recent numerical model by Anderson and Corry, Florida Current transports are resolved in a simple manner into barotropic and baroclinic modes. Although the barotropic mode is considerably more variable than the baroclinic, the basic annual signal obtained from the model also appears in the STACS observations. In particular, a rapid transport decrease in the fall with a secondary decrease in the spring are found in both model and observations.

Leetmaa, A., D.W. Behringer, A. Huyer, R.L. Smith, and J. Toole. Hydrographic conditions in the eastern Pacific before, during, and after the 1982-1983 El Ni�o. Progress in Oceanography, 19(1):1-47 (1987).

Between June 1981 and June 1984, a total of 13 CTD sections were made across the equator along 85°W. On some of these cruises additional sections were made along 5°S and 10°30'S between 85°W and the South American coast. This sampling period covers the events that took place during the 1982/1983 El Ni�o. These sections are used to describe the variability that took place before, during, and after this major event. At the surface, little evidence was found for a major southward flooding of warm, low salinity water from north of the equator that has been observed during some previous El Ni�os. Major changes took place in the sub-surface hydrographic structures. The thermostad between 13°C and 16°C, which is a prominent feature of the hydrography in this region, disappeared early in 1983 and reappeared early in 1984. The vertical temperature gradient along the equator and along the coast, which is usually quite variable with depth, became much more uniform in early 1983; it regained its normal structure by early 1984. Changes were not confined to the upper ocean but were evident over the whole depth interval sampled (1000 m). During November 1982, evidence was found for symmetric poleward spreading of the equatorial disturbance along the eastern boundary. Many of the changes that took place are consistent with linear models based on equatorial wave theory. These observations presented a unique opportunity for observing the ocean response to a major interannual change in the wind forcing.

Lord, S.J. The 17th Conference on Hurricanes and Tropical Meteorology, 7-10 April 1987, Miami, FL. Bulletin of the American Meteorological Society, 68(11):1431-1437 (1987).

No abstract.

Lord, S.J., and J.L. Franklin. The environment of Hurricane Debby (1982). Part I: Winds. Monthly Weather Review, 115(11):2760-2780 (1987).

A three-dimensional, nested analysis of wind fields in the environment of Hurricane Debby (1982) has been completed. The basic analysis tool uses a two-dimensional least-squares fitting algorithm combined with a derivative constraint that acts as a spatial low-pass filter on the analyzed field. Gridded results of horizontally analyzed fields are combined into vertical cross sections and then analyzed to produce vertical continuity. Consequently, a three-dimensional analysis is obtained. The database for the analysis comes primarily from Omega dropwindsondes (ODWs), rawinsondes, and satellite-derived winds above 400 mb in the environment of Hurricane Debby near 0000 UTC 16 September 1982. Since these data come from many different sources, and thus are not evenly distributed in the horizontal or vertical, techniques have been developed to alleviate difficulties associated with inhomogeneous data. The analyzed wind fields provide an independent evaluation of satellite-derived winds at and below 400 mb. General features of the environmental wind fields surrounding Debby are described. The wind analyses are then used to diagnose terms in the vorticity equation. The spatial orientation of a calculated dipole in the horizontal vorticity flux convergence term indicates that it is an approximate indicator of Debby's observed short-term motion. Finally, to provide an initial assessment of the wind analysis quality, experimental track forecasts with a barotropic model are performed with the layer-mean wind fields and operationally available data outside the analysis domain. Initial errors in the forecast tracks are directly related to the orientation of the diagnosed vorticity flux convergence dipole. The research wind analysis results in a substantial reduction in track error for short-term (12 h) forecasts compared to analyses from operationally available data. This reduction is due to an improved representation of the wind fields in the near-storm environment.

Lord, S.J., and J.L. Franklin. Wind analyses for the environment of Hurricane Debby (1982): Some diagnostic calculations and forecast experiments. Preprints, 17th Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 7-10, 1987. American Meteorological Society, Boston, 94-97 (1987).

No abstract.

Marks, F.D., and R.A. Houze. Inner core structure of Hurricane Alicia from airborne Doppler radar observations. Journal of the Atmospheric Sciences, 44(9):1296-1317 (1987).

Airborne Doppler radar measurements are used to determine the horizontal winds, vertical air motions, radar reflectivity, and hydrometeor fallspeeds over much of the inner-core region (within 40 km of the eye) of Hurricane Alicia (1983). The reconstructed flow field is more complete and detailed than any obtained previously. The data show both the primary (azimuthal) and secondary (radial-height) circulations. The primary circulation was characterized by an outward sloping maximum of tangential wind. The secondary circulation was characterized by a deep layer of radial inflow in the lower troposphere and a layer of intense outflow above the 10 km altitude. The rising branch of the secondary circulation was located in the eyewall and sloped radially outward. Discrete convective-scale bubbles of more intense upward motion were superimposed in this mean rising current, and convective-scale downdrafts were located throughout and below the core of maximum precipitation in the eyewall. Precipitation particles in the eyewall rainshaft circulated 18-20 km downwind as they fell, consistent with the typical upwind slope with increasing altitude of eyewall precipitation cores. Outside the eyewall, the precipitation was predominantly stratiform. A radar bright band was evident at the melting level. Above the melting level, ice particles were advected into the stratiform region from the upper levels of the eyewall and drifted downward through a mesoscale region of ascent. Hypothetical precipitation particle trajectories showed that as these particles fell slowly through the mesoscale updraft toward the melting level, they were carried azimuthally as many as 1 1/2 times around the storm. During this spiraling descent, the particles evidently grew vigorously. The amount of water condensed by the ambient mesoscale ascent exceeded that transported into the stratiform region by the eyewall outflow by a factor of 3. As the particles fell into the lower troposphere, they entered a mesoscale region of subsidence, the top of which coincided with the radar bright band.

Marks, F.D., and R.A. Houze. Three-dimensional structure of the eyewall of Hurricane Norbert as determined from an airborne Doppler radar. Preprints, 17th Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 7-10, 1987. American Meteorological Society, Boston, 347-350 (1987).

No abstract.

Maul, G.A. Report on INSMAP'86: The International Symposium on Marine Positioning. Marine Geodesy, 11(4):269-276 (1987).

The International Symposium on Marine Positioning, INSMAP'86, organized by the Marine Geodesy Committee of the Marine Technology Society, was held 14 to 17 October 1986, under the sponsorship of 17 organizations, at the U.S. Geological Survey National Center Auditorium in Reston, Virginia. INSMAP'86 was convened to focus attention on the special problems associated with positioning in the marine environment, to provide a timely forum for in-depth discussions and exchange of ideas, to identify immediate and future applications and requirements, and to promote inter-disciplinary and interagency collaboration between numerous investigators and users. The nine sessions and five workshops were attended by over 150 registered attendees representing North, Central, and South America, Europe, Asia, and Australia. In addition, 13 exhibitors set up demonstrations in the corridors leading to the auditorium. Forty-five papers, including invited addresses, were presented, and are available in a single volume of symposium proceedings.

Mayer, D.A., and J.C. Larsen. Tidal transport in the Florida Current and its relationship to tidal heights and cable voltages. Journal of Physical Oceanography, 16(12):2199-2202 (1987).

A linear relationship between tidal height (sea level of tidal frequencies) and tidal transport near 27°N in the Straits of Florida is confirmed. Transport estimates from this relationship for the O1 and M2 constituents are compared with those computed from cable voltages across the Florida Current. These estimates are independent in that the weighted tidal height model (tidal-height transport relationship) was developed using collective sets of current meter and velocity profiler data obtained at different times of the year and in different locations. The cable voltages, however, were calibrated using a quasi-synoptic sectional integration of depth-averaged profiler data. Further, a means is suggested by which changes in the cable calibration can be detected.

Molinari, R.L. Air mass modification over the eastern Gulf of Mexico as a function of surface wind fields and Loop Current position. Monthly Weather Review, 115(3):645-652 (1987).

The effects of surface wind patterns and Loop Current position on surface distribution of latent and sensible heat fluxes in the eastern Gulf of Mexico are demonstrated. Mean monthly fields of these fluxes computed from data collected during February 1975 and February 1976 are decomposed into two different modes, a north-wind mode associated with winter outbreaks of dry cold continental air masses and a trade-wind mode associated with advection from the south of warm moist maritime air. The distributions of sensible and latent heat fluxes are different for each mode, with both heat fluxes considerably larger over the northern Gulf, in particular, during times of the northerlies. However, during these two months, trade-wind days are more numerous and the mean monthly flux patterns reflect this preponderance. A simple model of the effect of extreme Loop Current configurations and the associated sea surface temperature distributions on air parcels traversing the Gulf below the inversion layer is presented. Total changes in air parcel temperature and specific humidity are shown to depend on the configuration of the Loop Current parcels which traverse the Gulf and cross the U.S. coastline between Louisiana and Florida during the time of a deep northern Loop intrusion and have 1.3°C higher temperatures and 1.0 g kg^-1 greater specific humidities than parcels which cross the Gulf during a shallow Loop intrusion.

Molinari, R.L. Ocean-atmosphere relations. In McGraw-Hill Yearbook of Science and Technology. McGraw-Hill, New York, 323-325 (1987).

No abstract.

Molinari, R.L., and D.V. Hansen. Observational studies of near-surface thermal budgets in the tropics: Review, evaluation, and recommendations. In Further Progress in Equatorial Oceanography, E.J. Katz and J.M. Witte (eds.). Nova University Press, For Lauderdale, 421-438 (1987).

No abstract.

Nelsen, T.A., G.P. Klinkhammer, J.H. Trefry, and R.P. Trocine. Real-time observation and tracking of dispersed hydrothermal plumes using nephelometry: Examples from the Mid-Atlantic Ridge. Earth and Planetary Science Letters, 81(2-3):245-252 (1987).

As part of the 1984-1985 NOAA VENTS program on the Mid-Atlantic Ridge, nephelometry was used to provide real-time detection and tracking of dispersed hydrothermal plumes. At all nine 1984 study sites, hydrothermal activity was detected by in-situ, real-time nephelometer measurements and later confirmed by dissolved Mn and particulate Fe measurements. These same techniques were employed in a site-specific survey of the Trans-Atlantic Geotraverse (TAG) area in 1985 where large water-column anomalies in turbidity and in dissolved Mn helped lead to the discovery of high-temperature black smokers. The optical response of the nephelometer was to hydrothermally-derived particulate matter. Thus, strong correlations existed between the nephelometer readings and total suspended matter (r = 0.98, n = 34), and particulate Fe (r = 88, n = 32). In addition, digital nephelometer data correlated well with dissolved Mn (r = 0.88, n = 78) throughout a large concentration range (0.2-31.0 nmol/kg). These data provide good evidence for the utility of in-situ nephelometer measurements for locating and surveying plumes from hydrothermal events. It also appears possible, within limits, to predict concentrations of in-situ total suspended matter, of particulate Fe and of dissolved Mn.

Ooyama, K.V. Numerical experiments of steady and transient jets with a simple model of the hurricane outflow layer. Preprints, 17th Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 7-10, 1987. American Meteorological Society, Boston, 318-320 (1987).

No abstract.

Ooyama, K.V. Scale-controlled objective analysis. Monthly Weather Review, 115(10):2479-2506 (1987).

The major topic of this paper is the resolvable spatial scales that can be analyzed by statistical interpolation of an undersampled data set. The inquiry was motivated by the need to design the most appropriate procedures for spatial analysis of the upper air sounding data from the GARP Atlantic Tropical Experiment. A reliable representation of horizontal scales in the analyzed wind fields was a matter of utmost concern, since the derived fields of vorticity, divergence, and vertical motion were also of vital interest. To achieve our goal, it was found that the traditional premise of statistical interpolation had to be reexamined. The main conclusions of this theoretical inquiry are: (1) resolvable scales are determined by the geometrical distribution of observing stations; (2) precise knowledge of the second-moment statistics improves the analysis by de-aliasing the amplitude of resolvable scales, but has no effect on the definition of resolvable scales; (3) residual effects of unresolvable signals in the data are removable by a spatial filter and must be so removed; and (4) spatial phases of de-aliased resolvable scales may still be in error. On the basis of these findings, the objective analysis procedures we have developed are targeted on the best achievable analysis of resolvable scales. The procedures include the following: an adequate estimate of "true" statistical fields from the given ensemble of data, a search for the optimum spatial filter by monitoring the targeted error variance, and a rational method of desensitizing the analysis to statistically errant data. In order to reduce the spatial phase error of propagating disturbances, the procedures are extended to the analysis of the time-wise Fourier-transformed data set (actually in the frequency-band analog). Since the wind is a physical vector, the entire procedure for the wind analysis is given in the tensor-invariant form, which is decidedly advantageous for very practical reasons. For example, the tensor approach eliminates the notorious ambiguity in normalization that is encountered in the multivariate approach. The paper also describes, in the Appendix, a method of filtered mechanical interpolation, which is specifically designed, with a variety of optional boundary conditions, for application to analysis in a finite domain.

Peng, T.-H. Modeling the seasonal variations of surface water CO₂ in the high-latitude North Atlantic Ocean. Proceedings, Marine Sciences Symposium, NSC Symposium Series No. 10, 199-209 (1987).

Seasonal variations in CO₂ partial pressure (pCO₂), total dissolved CO₂ (TCO₂), O₂, nutrients (PO₄, NO₃, and SiO₄), and temperature in surface water have been monitored at two stations, one located to the north and the other to the west of Iceland. Results of observations show that during the summer, pCO₂, TCO₂, and nutrients are the lowest, while the O₂ concentration is the highest. This trend is reversed during the winter. These seasonal variations are mainly the result of a deepening of the mixed layer during the winter and stratification coupled with intense biological activity during the summer. Photosynthetic utilization of the nutrient constituents during the long daylight time of summer in a strongly stratified and shallow surface mixed layer drives these changes. Enhanced mixing of surface water with deeper water during the winter brings the nutrient-rich deep water to the surface. Together with reduced biological activity due to decreased daylight, this mixing brings about higher concentrations of nutrient constituents and a higher TCO₂ and pCO₂. A simple box model representing the upper water column is devised to simulate the seasonal variations in the properties of surface water. It is shown that the model prediction of the seasonal variation of CO₂ and O₂ is consistent with observations.

Peng, T.-H., and W.S. Broecker. C/P ratios in marine detritus. Global Biogeochemical Cycles, 1(2):155-161 (1987).

Until reliable procedures have been developed to preserve the phosphorus contained in particulate matter captured by in-situ pumps and sediment traps and until these procedures are applied over a wide range of locations and depths in the sea, indirect methods will have to be used to determine the C/P ratio in marine detritus. We have taken two such approaches: (1) the use of C/N ratios for particulates captured in the upper thermocline in conjunction with O₂/P and N/P ratios obtained from deconvolutions of ocean chemical data and (2) regression along isopycnals in the deep-sea waters free of fossil fuel CO₂. While neither approach yields a definitive answer, both suggest that a value of 127 carbon atoms per phosphorus atom would be a more appropriate interim value than that of 106 adopted long ago by A.C. Redfield and his associates.

Peng, T.-H., T. Takahashi, W.S. Broecker, and J. Olafsson. Seasonal variability of carbon dioxide, nutrients, and oxygen in the northern North Atlantic surface water: Observations and a model. Tellus, 39B:439-458 (1987).

The seasonal variation of various surface water properties has been monitored at a station located at about 120 miles south of the Iceland-Greenland sill during the two-year period, March 1983 through May 1985. These properties include the temperature, salinity, mixed-layer depth, partial pressure of CO₂ in seawater and the concentrations of dissolved total CO₂, oxygen, and nutrients. It was observed that during the summer, the CO₂ partial pressure and the concentrations of CO₂ and nutrients in surface water were lowest, while the oxygen concentration was highest. This situation was reversed during the winter. The seasonal variation is attributed mainly to the high photosynthetic utilization rate of carbon and nutrients in a strongly stratified and shallow surface mixed layer during the summer. The winter observations are attributed to the upward transport of deep waters rich in total CO₂ and nutrients by deep convective mixing. In order to account for the observed seasonal variation, a vertically one-dimensional, two-box ocean model has been constructed. The vertical mixing between the surface mixed layer and deep water is characterized in terms of changes in the mixed layer thickness with time, and the biological productivity is related to the solar insolation and nutrient concentration in the mixed layer. Gas exchange of oxygen and CO₂ between the mixed layer and the atmosphere is taken into consideration. When this model is calibrated using the observed phosphate concentration in surface water, it yields seasonal variations of carbon and oxygen values consistent with the observations, with an exception of a large excursion of spring time values resulting from phytoplankton blooms. It is shown that the spring bloom effect can be simulated by a short-term reduction of the phosphate residence time and of the gas exchange rate.

Powell, M.D. Boundary-layer structure in convective hurricane rainbands. Preprints, 17th Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 7-10, 1987. American Meteorological Society, Boston, 373-376 (1987).

No abstract.

Powell, M.D. Changes in the low-level kinematic and thermodynamic structure of Hurricane Alicia (1983) at landfall. Monthly Weather Review, 115(1):75-99 (1987).

Aircraft, land station, and buoy data were composited with respect to the center of Hurricane Alicia (1983) for three 8 h periods corresponding to prelandfall in the open Gulf of Mexico, landfall in the Galveston area, and postlandfall in the vicinity of Houston. Comparison of the wind analyses before, during, and after landfall emphasizes the land-sea frictional asymmetry at landfall. In addition, other asymmetries in the surface wind field and differences between the flight-level and the surface wind fields are revealed. The asymmetric structure of the surface wind field may be interpreted as having resulted from the combined effects of land-sea roughness differences, background environmental flow, and storm translation. The land-sea frictional difference acted to oppose the mean vortex flow over land and reinforce it over water. The southwest background environmental flow acted nearly parallel to the coastline, producing surface inflow on the left side and outflow on the right side, while the effect of the storm translation increased winds on the right and decreased winds on the left. At landfall, the analysis revealed a broad region of high wind speeds and a mesoscale divergence-convergence couplet along the outer rainband axis just offshore on the northeast (right) side of the storm. The outer rainband axis acted as an obstruction to the surface flow, separating the warmer central core of the storm from the environment through which the storm moved. In contrast to recent numerical model studies, surface convergence was also noted on the left side of the storm just offshore, despite outflow at flight level. Analyses of temperature, dew point, and equivalent potential temperature indicate that loss of the oceanic heat and moisture source, combined with advection of drier air on the landward side of the storm, was responsible for cooling and drying of the inflowing boundary layer air. Upon introduction of this air into the core convection and vertical ascent, a decrease in the release of latent heat could then lead to cooling in the middle levels of the storm and a subsequent increase in the central sea-level pressure.

Powell, M.D., and P.N. Georgiou. Response of the Allied Bank Plaza tower during Hurricane Alicia (1983). Journal of Wind Engineering and Industrial Aerodynamics, 26(2):231-254 (1987).

As Hurricane Alicia passed over Houston on August 19, 1983, a record lasting approximately 90 minutes was obtained of the wind-induced accelerations of the tallest building in the downtown area, the Allied Bank Plaza. Coincidently, the building had been the subject of a detailed wind tunnel model study several years earlier, the results of which included the prediction of building accelerations as a function of wind speed and wind direction. From the many wind observations made during Alicia's passage inland, it was possible to reconstruct the wind speeds and directions experienced at the Allied Bank Plaza site which overlapped the period of the acceleration record. This reconstructed wind history was combined with the wind tunnel test data to compute a time series of estimated accelerations sustained by the building during Alicia's passage inland. The resulting favorable comparison of actual and predicted accelerations provides a valuable case study, illustrating the reliability of wind tunnel modeling within the design process for tall buildings.

Roffer, C., and D.W. Behringer. CTD/O₂ data collected in 1985 and 1986 for EPOCS. NOAA Data Report, ERL AOML-9 (PB88-160775), 266 pp. (1987).

A summary of CTD measurements collected during four cruises in 1985 and 1986, as part of the Equatorial Pacific Ocean Climate Studies (EPOCS) program, are presented. These cruises continued the EPOCS program efforts along 110°W and 85°W, and extended the research area southeast along 15°S. Station locations and profiles of temperature, salinity, and sigma-T are plotted for each cast. Dissolved oxygen bottle values, theta-s diagrams, and temperature and salinity sections are shown.

Romero, G.C., G.R. Harvey, and D.K. Atwood. Stranded tar on Florida beaches: September 1979-October 1980. Caribbean Journal of Science, 23(1):65-72 (1987).

Amounts of tar stranded on Florida beaches were determined periodically over one year (September 1979-October 1980). Results show that tar fouling of southeast Florida beaches is an order of magnitude greater than the rest of the state. This may result from the extensive ship traffic in the Straits of Florida. There is no evidence that any Florida beaches received increased amounts of tar as a result of the 1979 IXTOC-1 blowout in the southern Bay of Campeche. There is also no evidence that the amounts of tar on southeast Florida beaches have increased over amounts measured in API studies conducted in 1958 and 1971.

Rona, P.A. Hydrothermal mineralization at slow-spreading centers: The Atlantic model. Marine Mining, 6(1):1-7 (1987).

The recent discovery of the first black smoker-type hydrothermal venting and massive sulfide mineral deposits at a site in the rift valley of the slow-spreading Mid-Atlantic Ridge near latitude 26°N, longitude 45°W demonstrates that a complete series of hydrothermal mineral deposit types exists at slow-spreading oceanic ridges (half-rate less than or equal to 2 cm/yr). Subseafloor hydrothermal convection driven by magmatic heat sources appears to be similar at slow- and faster-spreading centers. However, differences exist in the periodicity of magmatic cycles that energize hydrothermal circulation. These findings have favorable implications for the occurrence of sizable hydrothermal mineral deposits on slow-spreading oceanic ridge systems.

Rona, P.A. Ocean ridge crest processes. U.S. National Report to International Union of Geodesy and Geophysics, 1983-1986. Reviews of Geophysics, 25(5):1089-1114 (1987).

Oceanic ridge crest processes constitute a vigorous frontier of multi-disciplinary research with global ramifications in the earth, atmospheric, and biologic opening in response to investigations which are elucidating the role of these processes in the lithosphere, hydrosphere, atmosphere, and biosphere, and the application of advanced instrumental and interpretive techniques which are increasing the quality and quantity of data. These techniques include crustal drilling with borehole logging (Deep Sea Drilling Project reports), high-resolution bathymetry (Sea Beam, etc.), side-scan sonar (SeaMARC I and II, GLORIA, etc.), imagery with video and photography, multichannel seismics, determination of water column properties (CTD with rosette sampler, etc.), and submersible applications. Commentary and bibliography reporting this research are divided into consideration of magmatic, tectonic, hydrothermal, sedimentary, and biologic processes. In the extensive bibliography of publications from 1982 through 1986, papers treating each of these processes are subdivided into specific oceanic ridges and ophiolites; the papers are further subdivided into physics, chemistry, and history according to their emphasis. The bibliography was compiled from three databases, supplemented by a general search of the literature. The databases comprised GEOREF, which was the most comprehensive for earth sciences but lacked abstracts; OCEANIC ABSTRACTS, which included abstracts; and BIOSIS, which provided biological references.

Rona, P.A. The Indian Ocean: Exploitable mineral and petroleum resources. Economic Geology, 82:1396-1397 (1987).

No abstract.

Rona, P.A., L. Widenfalk, and K. Bostrom. Serpentinized ultramafics and hydrothermal activity at the Mid-Atlantic Ridge crest near 15°N. Journal of Geophysical Research, 92(B2):1417-1427 (1987).

The initial occurrence of serpentinized ultramafic rocks at the nontransform intersection of a wall of a rift valley with the wall of a fracturue zone is described from a site at the Fifteen Twenty Fracture Zone. The ultramafics crop out in block-faulted terrain on the upper portion of the eastern intersection between the rift valley and fracture zone walls in water depths between 2,910 and 3,300 m. They comprise cumulate harzburgites, pyroxenites, lherolites, and wehrlites, as well as gabbronorites, olivine gabbronorites, gabbropegmatites, and alteration products including serpentinites, bastite serpentinites, and asbestos. The Ti-Zr-Y relations and relatively constant Zr/Ti ratio in basalts recovered with the ultramafic rocks indicate a cogenetic relation from a common magmatic source that has undergone a late stage differentiation in the lower crust. Ongoing hydrothermal activity is indicated by chemical anomalies in the near-bottom water at the ultramafic outcrop. The upwelling hydrothermal circulation apparently follows crust-penetrating faults that may have controlled the diapiric ascent of the serpentinites and that continue to tap degassing magma and/or mantle. The observations presented indicate that ultramafic cumulates form beneath the rift valley adjacent to long-offset (>100 km) ridge-ridge transform faults, where they are serpentinized by hydrothermal processes within the initial 1 x 10⁶ years of generation of lithosphere at a slow-spreading axis. The corners formed by the intersections of the walls of a rift valley with both the transform (RT corner) and the nontransform (RN corner) portions of these fracture zones are principal loci of diapiric emplacement of serpentinized ultramafics.

Sanford, T.B., P.B. Black, J.R. Haustein, J.W. Feeney, G.Z. Forristall, and J.F. Price. Ocean response to a hurricane. Part I: Observations. Journal of Physical Oceanography, 17(11):2065-2083 (1987).

The response of the ocean was investigated using aircraft-deployable expendable current profilers (AXCP). The goals were to observe and separate the surface wave and surface mixed-layer velocities under the storms and to map the across-track and along-track velocity and temperature response in the mixed layer and thermocline. Custom instrumentation was prepared, including slower falling AXCPs, and the AXCP equipment was installed on NOAA WP-3D aircraft. Research flights were made into two 1984 hurricanes: Norbert, in the western Pacific off Baja, California (19°N, 109°W); and Josephine, off the west coast of the U.S. (29°N, 72°W). Thirty-one probes were deployed in each hurricane. All but four AXCPs survived the 220-knot launch and wave-zone impact (surface winds up to 75 knots) and produced basic RF transmissions. About half the AXCPs provided temperature and velocity profiles. Most velocity profiles exhibited strong surface wave contributions, slab-like velocities in the SML, strong shears beneath the SML, and only weak flows in the upper thermocline. Separation of the surface gravity wave velocities from the steady and inertial motions was obtained by fitting the profiles to steady flows and shears in three layers and to a single surface wave at all levels. The velocity profiles displayed large divergences to the horizontal SML velocities in the wake of the hurricanes. The observations show a strong enhancement to the right of the storm as expected from numerical simulations. The largest SML velocities were 1.1 m s^-1 in Norbert and 0.73 m s^-1 in Josephine. Numerical simulations will be compared with the observations in Part II.

Shapiro, L.J. Month-to-month variability of the Atlantic tropical circulation and its relationship to tropical storm formation. Monthly Weather Review, 115(11):2598-2614 (1987).

Monthly mean winds have been derived from 200 mb and Analysis of the Tropical Oceanic Lower Layer (ATOLL) winds over the southern North Atlantic, Caribbean, Gulf of Mexico, and eastern Pacific during the hurricane seasons (June-November) of 1975 through 1985. After removal of the seasonal cycle, the winds are expressed in terms of empirical orthogonal functions. The dominant mode of variability for the combined 200 mb/ATOLL circulation strongly resembles part of a Walker cell confined near the equator. This mode is strongly correlated with El Ni�o index (Weare, 1986), and is associated with the El Ni�o/Southern Oscillation. A positive (El Ni�o-like) index tends to be associated with more anticyclonic vorticity at the ATOLL level in the tropics and increases in the vertical shear between about 10° and 30°N. This circulation is unfavorable for tropical storm formation. Correlations are derived between the monthly mean winds and monthly tropical storm frequency in the Atlantic basin. Contemporaneous correlations in August, September and October, the three most active months, as well as correlations between winds and tropical storm formation one and two months later, are computed. Predictability of monthly tropical storm frequency at the two-month lead is statistically significant, with true skill approximately 45% of the variance. Only one-sixth of this skill is associated with the El Ni�o/Southern Oscillation A favorable environment for storm formation is apparently established at least two months before the given month of formation. The results extend and complement predictions of seasonal tropical storm activity and previous hypotheses concerning the influence of El Ni�o on storm formation.

Shapiro, L.J. Month-to-month variability of the Atlantic tropical circulation and its relationship to tropical storm formation. Preprints, 17th Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 7-10, 1987. American Meteorological Society, Boston, 231-233 (1987).

No abstract.

Shay, L.K., R.L. Elsberry, and P.B. Black. Mesoscale ocean temperature and current patterns induced by hurricanes. Preprints, 17th Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 7-10, 1987. American Meteorological Society, Boston, 388-392 (1987).

No abstract.

Simpson, R.H., J. Simpson, and S.L. Rosenthal. Hurricane. In Encyclopedia of Science and Technology, 6th Edition, Volume 8, McGraw-Hill, New York, 544-557 (1987).

No abstract.

Spillane, M.C., D.B. Enfield, and J.S. Allen. Intraseasonal oscillations in sea level along the west coast of the Americas. Journal of Physical Oceanography, 17(3):313-325 (1987).

Hourly observations of coastal sea level at stations from Peru to British Columbia are analyzed for low frequency content. A space-time contour plot of sea level, from four years of data during the 1971-75 period, shows the meridional structure of the seasonal cycle and interannual variability associated with the 1972-73 El Niño. Oscillations with intraseasonal periods of 36-73 days are also evident, coherent over alongshore distances of several thousand kilometers. Further investigation using spectral methods and empirical orthogonal function analysis in the frequency domain reveals, in particular, that intraseasonal sea level variability has a peak in spectral density along the coasts of South America, Central America and Mexico, with high coherence from near the equator (Tumaco, 2°N) north to central California (34°N) and south to at least Callao (12°S). Phase propagation north of the equator is poleward at 150-200 kilometers/day. Atmospheric pressure, alongshore wind stress and wind stress curl, derived from Fleet Numerical Oceanography Center data for the Northern Hemisphere, are used to assess the importance of local atmospheric forcing. The low coherence between sea level and these fields in the intraseasonal frequency band suggests that the observed oscillation may be a coastally propagating response to remote processes in the equatorial Pacific waveguide.

Tanner, A., C.T. Swift, and P.B. Black. Operational airborne remote sensing of wind speeds in hurricanes. Preprints, 17th Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 7-10, 1987. American Meteorological Society, Boston, 385-387 (1987).

No abstract.

Velden, C.S., and S.B. Goldenberg. The inclusion of high-density satellite wind information in a barotropic hurricane forecast model. Preprints, 17th Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 7-10, 1987. American Meteorological Society, Boston, 90-93 (1987).

No abstract.

Wilburn, A.M., E. Johns, and M.H. Bushnell. Current velocity and hydrographic observations in the Straits of Florida, the Caribbean Sea, and offshore of the Antillean Archipelago: Subtropical Atlantic Climate Study (STACS), 1984 and 1985. NOAA Data Report, ERL AOML-8 (PB88-149299), 200 pp. (1987).

The primary objectives of the Subtropical Atlantic Climate Study (STACS) are to increase the understanding of the dynamics of the North Atlantic subtropical gyre and to define which oceanographic processes are important in meridional heat flux. As the Florida Current has been shown to play an important role in this flux, the initial emphasis of STACS was to develop the capability to monitor the variability of oceanic heat and mass transport in the Straits of Florida.

Wilburn, A.M., E. Johns, and M.H. Bushnell. Current velocity and hydrographic observations in the Straits of Florida, the Caribbean Sea, and offshore of the Antillean Archipelago: Subtropical Atlantic Climate Study (STACS), 1986. NOAA Data Report, ERL AOML-10 (PB88-160767), 253 pp. (1987).

The objectives of the Subtropical Atlantic Climate Study (STACS) are to increase understanding of the dynamics of the North Atlantic subtropical gyre and to define which oceanographic processes are important in meridional heat flux. As the Florida Current has been shown to play an important role in the flux, the initial emphasis of STACS was to develop the capability to monitor the variability of oceanic heat and mass transport in the Straits of Florida.

Willis, P.T., and F.D. Marks. Convective-scale transports in a mature hurricane. Preprints, 17th Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 7-10, 1987. American Meteorological Society, Boston, 343-346 (1987).

No abstract.

Willoughby, H.E. Tropical cyclone track prediction: Some theoretical aspects. Preprints, 17th Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 7-10, 1987. American Meteorological Society, Boston, 262-265 (1987).

No abstract.

Willoughby, H.E., and W.P. Barry. Real-time data acquisition and analysis in Hurricane Charley of 1986. Preprints, 17th Conference on Hurricanes and Tropical Meteorology, Miami, FL, April 7-10, 1987. American Meteorological Society, Boston, 341-342 (1987).

No abstract.

Zhang, J.-Z., H. Jiazhen, L. Bianling, and L. Faxi. The kinetics of oxidation of hydrogen sulfide by dissolved oxygen in seawater. Donghai Marine Science, 5(3):71-77 (1987).

The rate of oxidation of hydrogen sulfide by oxygen has been studied in both a 0.5 M NaCl solution and in seawater over a range of pH and temperature in the presence of metal sulfide precipitation. The results indicate that maximum reaction rates in pH appear at about 7 and great reactions rates in pH at between 9 and 12. The activation energy of the reaction at pH 8.5 in 0.5 M NaCl solution was 25 kcal/mol. The visible light did not affect the reaction rate obviously. The catalysis of FeS, MnS, CuS, and NiS on the reaction has been observed in both the 0.5 M NaCl solution and in seawater, but Mg²⁺, Al³⁺, and CdS did not catalyze the reaction. **1986**

Andree, M., H. Oeschger, W.S. Broecker, N. Beavan, M. Klas, A. Mix, G. Bonani, H.J. Hoffman, M. Suter, W. Woelfli, and T.-H. Peng. Limits on the ventilation rate for the deep ocean over the last 12,000 years. Climate Dynamics, 1:53-62 (1986).

In this paper we present accelerator radiocarbon measurements on hand-picked benthic and planktonic foraminifera separated from two deep sea cores raised from the South China Sea. From the benthic-planktonic age differences we are able to place limits on the extent to which the ventilation rate of the deep Pacific Ocean has changed over the last 12,000 years. While much work remains to be done before any definitive answers for the global oceans can be given, these results on cores with sedimentation rates suitably high to avoid major corrections for bioturbation effects suggest that the ventilation rate of the deep Pacific Ocean has remained nearly the same throughout Holocene time. Further, there is no suggestion that the rate was slower during the period of major glacial retreat. These results confirm that the changes in atmospheric ¹⁴C/C ratio over the last 10,000 years owe their origin to radiocarbon production rate changes.

Bitterman, D.S., and D.V. Hansen. The design of a low cost tropical drifter buoy. Proceedings, '86 Marine Data Systems International Symposium, New Orleans, LA, April 30-May 2, 1986. The Marine Technology Society, 575-581 (1986).

Since 1979, the NOAA/Atlantic Oceanographic and Meteorological Laboratory (NOAA/AOML) has been deploying satellite-tracked drift buoys in the tropical Atlantic and Pacific Oceans in support of various long-term laboratory field programs. In order to reduce the cost and eliminate the long procurement lead times associated with commercially available buoys, a simple, relatively inexpensive drift buoy was designed for use in these equatorial areas. This paper describes the construction of the buoy, the results of field tests of the drogue to directly measure its effectiveness under various wind and sea conditions, and illustrates the results of buoy deployments in the open ocean as part of the scientific program.

Black, P.G., F.D. Marks, and R.A. Black. Supercell structure in tropical cyclones. Preprints, 23rd Conference on Radar Meteorology, Snowmass, CO, September 22-26, 1986. American Meteorological Society, Boston, JP255-259 (1986).

No abstract.

Black, P.G., R.A. Black, J. Hallett, and W.A. Lyons. Electrical activity of the hurricane. Preprints, 23rd Conference on Radar Meteorology, Snowmass, CO, September 22-26, 1986. American Meteorological Society, Boston, J277-J280 (1986).

No abstract.

Black, P.G., R.W. Burpee, N.M. Dorst, and W.L. Adams. Appearance of the sea surface in tropical cyclones. Weather and Forecasting, 1(1):102-107 (1986).

No abstract.

Black, R.A. Microphysical investigations above the melting level in Hurricane Norbert (1984). Preprints, 23rd Conference on Cloud Physics, Snowmass, CO, September 22-26, 1986. American Meteorological Society, Boston, JP252-254 (1986).

No abstract.

Black, R.A., and J. Hallett. Observations of the distribution of ice in hurricanes. Journal of Atmospheric Science, 43(8):802-822 (1986).

Observations of the type and distribution of particles above the 0°C isotherm in three Atlantic hurricanes are presented. Supercooled drops, graupel, columns, and aggregated snowflakes were observed. The supercooled drops were found only in convective updrafts stronger than 5 m s^-1, but not all updrafts >5 m s^-1 contained appreciable liquid. Graupel was found in all updrafts at temperatures <-2°C, and small columns were sometimes found in downdrafts. Nonconvective rainbands contained 15-30 L^-1 of snow composed of columns and what appeared to be large aggregates. Other stratiform regions contained 1-15 L^-1 of medium and large aggregates; columns were occasionally found there also but only within about 15 km of convection. Hurricane convection is almost completely glaciated at the -5°C level. It is suggested that the ice particles observed at 6 km inside the convection result primarily from downward mixing on both sides of the eyewall updraft of ice formed in the convective areas at higher, colder levels. The ice in the stratiform areas is believed to have fallen from the high-level (6 km and higher) eyewall outflow.

Bravo, N.J., and G.A. Maul. Corrections to and extension of "Fitting of satellite and in-situ ocean surface temperatures: Results for POLYMODE during the winter of 1977-1978." Proceedings, U.S.-India Symposium-Cum-Workshop on Remote Sensing Fundamentals and Applications, March 11-15, 1985, Space Applications Centre, Ahmedabad 380 053, India, 63-88 (1986).

It was found that in an earlier article on the POLYMODE area (Maul and Bravo, 1983) the surface data (ship temperature reports) were read-in incorrectly; reports from all three months considered were erroneously used in the computations for each month. In the process of correcting the results, temperature maps for 45 usable days from December 1977 through February 1978 were obtained using the following procedures already described in the previous work: ratio method, departure method, plane and quadratic polynomial least-square surface fits, and linear regression of the reported surface temperatures on the satellite raw temperatures. In addition, two-dimensional interpolation was used in the present work. The composite temperature map using the ratio method for the usable 45 days exhibited Gulf Stream temperatures up to 2°K higher than the previously published map. Temperatures elsewhere were about the same. Daily maps produced by the radio and departure methods were usually within +1°K of each other at most cloud-free pixels. The plane least-squares surface usually approximated either the ratio or the departure method to +1°K while the bivariate interpolation and the quadratic least-square surface usually varied +1°K further. The linear regression maps deviated abruptly from the others in the coastal areas. Agreement between the methods seemed to improve with the number of available surface observations, as well as with the uniformity of their areal distribution throughout the POLYMODE region. A split 10 µm-13 µm window correction using the GOES VAS is tested for post POLYMODE sea surface temperature retrievals; calculations suggest an error of +1.2°K is possible and, therefore, other multispectral methods need to be investigated.

Broecker, W.S., and T.-H. Peng. Carbon cycle: 1985. Glacial to interglacial changes in the operation of the global carbon cycle. Radiocarbon, 28(2A):309-327 (1986).

The hottest topic for those interested in the earth's carbon cycles is the change in atmospheric CO₂ content between glacial and interglacial time. What caused it? What is its role in glacial cycles? We evaluate here the hypotheses that have been put forward to explain the CO₂ change with evidence from deep sea sediments. We conclude that all the hypotheses have serious drawbacks and that much effort will have to be expended in gathering more data from ice cores and ocean sediments before we will be pointed toward the correct scenario. Also, thoughtful modeling aimed at depicting the ties between pCO₂, O₂, ¹³C/¹²C, ¹⁴C/¹²C, and nutrient constituents in the sea for various modes of circulation will have to be done before the evidence from ocean cores can be properly interpreted.

Broecker, W.S., T.-H. Peng, and G. Ostlund. The distribution of bomb tritium in the ocean. Journal of Geophysical Research, 91(C12):14,331-14,344 (1986).

A global picture of the water column inventories of bomb-produced tritium is constructed from the GEOSECS data set. This picture is compared with that obtained by combining the bomb tritium input function of Weiss and Roether (1980) with the bomb radiocarbon calibrated lateral redistribution model of Broecker et al. (1985). While differences between the calculated and observed distribution exist, they are surprisingly small. Tritium distributions calculated using the lateral redistribution model provide predictions of the changes to be expected in the next few decades. Such predictions are essential to the design of sound strategies for continued monitoring of the tritium transient.

Broecker, W.S., J.R. Ledwell, T. Takahashi, R. Weiss, L. Merlivat, L. Memery, T.-H. Peng, B. Jahne, and K.O. Munnich. Isotopic versus micrometeorologic ocean CO₂ fluxes: A serious conflict. Journal of Geophysical Research, 91(C9):10,517-10,527 (1986).

Eddy correlation measurements over the ocean give CO₂ fluxes an order of magnitude or more larger than expected from mass balance measurements using radiocarbon and radon 222. In particular, Smith and Jones (1985) reported large upward and downward fluxes in a surface zone at supersaturations of 15% and attributed them to the equilibration of bubbles at elevated pressures. They argue that even on the open ocean such bubble injection may create steady state CO₂ supersaturations and that inferences of fluxes based on air-sea pCO₂ differences and radon exchange velocities must be made with caution. We defend the global average CO₂ exchange rate determined by three independent radioisotopic means: prebomb radiocarbon inventories; global surveys of mixed layer radon deficits; and oceanic uptake of bomb-produced radiocarbon. We argue that laboratory and lake data do not lead one to expect fluxes as large as reported from the eddy correlation technique; that the radon method of determining exchange velocities is indeed useful for estimating CO₂ fluxes; that supersaturations of CO₂ due to bubble injection on the open ocean are negligible; that the hypothesis that Smith and Jones advance cannot account for the fluxes that they report; and that the pCO₂ values reported by Smith and Jones are likely to be systematically much too high. The CO₂ fluxes for the ocean measured to date by the micrometeorological method can be reconciled with neither the observed concentrations of radioisotopes of radon and carbon in the oceans nor the tracer experiments carried out in lakes and in wind/wave tunnels.

Burpee, R.W. Mesoscale structure of hurricanes. In Mesoscale Meteorology and Forecasting, P.S. Ray (ed.). American Meteorological Society, Boston, 311-330 (1986).

No abstract.

Chelton, D.B., and D.B. Enfield. Ocean signals in tide gauge records. Journal of Geophysical Research, 91:9081-9098 (1986).

Tide gauges are designed to measure changes in water level relative to land. However, vertical motions of the earth's crust manifest themselves as apparent water level changes in tide gauge records. These crustally-induced changes are often small in amplitude relative to the wide range of oceanic processes which affect water level in coastal regions. Vertical crustal motion can best be studied by first removing oceanic variability from the time series. In this paper we summarize the major oceanic signals in tide gauge records. We take the approach that the oceanic signals are unwanted "noise" in the data. Methods are described for removing or at least reducing the various oceanic signals. These oceanic signals span a broad range of time scales from tides to interannual variability associated with the El Niño phenomenon and secular sea level change from a number of oceanographic effects.

Chew, F. A comment on satellite flow imagery northwest of Cuba during October 1985. Oceanographic Monthly Summary, 6(1):12-13 (1986).

Compared to the segment of the Gulf Stream system downstream (north) of Miami, Florida, few comprehensive in-situ data studies are available in the upstream segment north of Cuba to support the shape of the Gulf Stream there as revealed in satellite imagery. The October 1985 satellite imagery for the Gulf of Mexico is an exception, for it shows a feature that was first observed by means of free-drifting drogues in August 1971. If the flow south of 25°N is assumed to follow the edge of the current, the September Loop Current is seen to enter the Florida Strait along a loose cyclonic path swinging far to the south. In contrast, the October Loop Current south of 25°N proceeds farther west before making a tight cyclonic turn near 24°N, 86°W and enters the Florida Strait in an initially anticyclonic flow.

Clarke, T.L. Radiation pressure induced instability in Saturn's rings. Astrophysical Letters and Communications, 25:51-56 (1986).

No abstract.

Clarke, T.L., and J.R. Proni. Remote acoustical measurement of ocean bottom parameters. In Current Practices and New Technology in Ocean Engineering, T. McGuinnes and H. Shih (eds.). American Society of Mechanical Engineers, Volume 2, New York, 145-148 (1986).

The use of acoustics in measuring ocean bottom characteristics has been in progress a number of years. Three of the most widely studied acoustical features have been returned pulse amplitude (generally peak amplitude), pulse attenuation, and sub-bottom sound speed. Recently, overall returned pulse shape has been examined as an acoustical feature for sediment classification. An acoustical bottom and sub-bottom sound reflection and scattering model has been developed in NOAA for the purpose of deriving an improved definition of the bottom for charting purposes. A key question being studied is what are those acoustic features relatable to certain bottom physical features such as the shear modulus profile? A discussion of a new application of coherent transverse Doppler to bottom sound speed profile measurements and other profile measurements will be given. A sensitivity analysis of sound speed versus backscattered acoustical intensity will also be presented. Results of the NOAA model will be presented for acoustical frequencies covering the interval from 10 kHz to 200 kHz for various bottom types. Two-dimensional, frequency-time, intensity contours will be presented with particular attention to describing and distinguishing specular reflection, bottom surface-scattering and bottom volumetric scattering regimes. Comparison of typical fluid mud structures with those of sand type bottoms will be given with a discussion of certain esoteric "internal wave" induced "fluid mud like" episodes. Confusion produced in standard echo-sounding systems by such phenomena will be illustrated.

Enfield, D.B. Zonal and seasonal variability of the equatorial Pacific heat balance. Journal of Physical Oceanography, 16(6):1038-1054 (1986).

This study calculates a detailed climatological inventory of the oceanic heat balance in the equatorial Pacific. The gridded climatology of Weare et al. is used as an estimate of net surface heating. Zonal and meridional/vertical advection are estimated in a manner similar to that of Wyrtki, using the gridded climatologies for wind stress (Wyrtki and Meyers) and sea surface temperature (Reynolds), plus estimates of zonal transport. In addition, the meridional diffusion of heat into the cold tongue has been estimated from the work of Hansen and Paul and the terms of the heat balance have been resolved by ten-degree longitude zones and by month of the year. The computed residual heat flux has been examined for consistency with expectations about the remaining, vertical diffusion process. The effects of using the alternate climatologies of Esbensen and Kushnir and Reed for the net surface heating are also calculated. The total advective heat flux divergence is calculated to be -27 � 7, -91 � 17 and -48 � 17 W m^-2, respectively, in the western, central and eastern equatorial Pacific with meridional advection and upwelling removing about three times as much heat as zonal advection. The advective contributions are in approximate agreement with Wyrtki's "likely case" estimates for the 100°W-170°E longitude zone. The contributions from zonal advection, meridional advection and meridional diffusion are found to be greatest during the Boreal fall, winter and fall-winter seasons, respectively. Depending on the climatology used for the net surface heat gain, the assumption of a uniform meridional diffusivity of 2 × 10⁴ m² s^-1 leads to physically unrealistic residual flux divergences that imply a heat gain from vertical turbulence in the central Pacific or that vertical turbulence removes much more heat from the western and eastern Pacific than from the central Pacific. Total neglect of the meridional diffusion exacerbates the problems. Increasing the meridional diffusivity to 6 × 10⁴ m² s^-1 in the central Pacific, consistent with direct estimates by Hansen and Paul, gives zonally uniform, negative residuals that are physically consistent with existing measurements of equatorial turbulence. With the model so tuned, the "best guess" heat balance in the central Pacific involves significant contributions from all terms, in the western Pacific between surface heat gain from the atmosphere and losses due to vertical diffusion, and in the eastern Pacific between surface gain and losses due to meridional advection (upwelling) and vertical diffusion.

Friedman, H.A., and O.E. Thompson. First International Conference on School and Popular Meteorological Education, Oxford, England, July 2-4, 1984. Bulletin of the American Meteorological Society, 67(4):422-425 (1986).

The First International Conference on School and Popular Meteorological Education convened at Lady Margaret Hall, one of the colleges of Oxford University. The conference, held from July 2-4, 1984, was organized by the Royal Meteorological Society (RMS) and was cosponsored by the American Meteorological Society (AMS) and the World Meteorological Organization (WMO). The AMS Board of School and Popular Meteorological and Oceanographic Education (BSPMOE) played an active, though relatively minor, role in helping to structure the conference by developing interest among potential participants in the United States, including educators, meteorological instrument manufacturers and distributors, scientists, school career counselors, representatives of the electronic and print media, and publishers of meteorological and related textbooks and other educational materials. The chairperson of the Conference Organizing Committee was J.M. Walker, education secretary of RMS.

Gamache, J.F. Bulk water-budget components in Hurricane Norbert as determined from airborne radar and Doppler observations. Preprints, 23rd Conference on Radar Meteorology, Snowmass, CO, September 22-26, 1986. American Meteorological Society, Boston, JP244-247 (1986).

No abstract.

Gamache, J.F. Particle characteristics in stratiform and convective clouds observed during summer MONEX. Preprints, Conference on Cloud Physics, Snowmass, CO, September 22-26, 1986. American Meteorological Society, Boston, J143-J146 (1986).

No abstract.

Garzoli, S.L., and M.E. Clements. Indirect wind observations in the southwestern Atlantic. Journal of Geophysical Research, 91(C9):10,551-10,556 (1986).

Two time series of wind speed have been inferred from ambient noise measurements obtained with bottom deployed inverted echo sounders in the southwestern Atlantic. The wind records from the two instruments, deployed 181 km apart, show significant differences at low frequencies. The mean speed for the recorded period is 10 m/s. The energy density spectra of the inferred wind records show a decrease in energy with frequency with a slope of -1.7 for frequencies between 0.22 and 20 cpd. The analysis to the spectra from the time series at the two moored locations shows differences in the band of 2-10 days. An increase in the variance is detected in the offshore location at discrete periods corresponding to atmospheric oscillations. These oscillations are considerably less energetic in the continental shelf-slope regime but are coherent in both locations.

Govoni, J.J., P.B. Ortner, F. Alyamani, and L.C. Hill. Selective feeding of spot (Leiostomus xanthurus) and Atlantic croaker (Micropogonias undulatus) larvae in the northern Gulf of Mexico. Marine Ecology Progress Series, 28(1-2):175-183 (1986).

When examined in relation to their availability in the plankton, the organisms eaten by larval spot, Leiostomus xanthurus, and Atlantic croaker, Micropogonias undulatus, collected in the northern Gulf of Mexico indicated that these larvae feed selectively. Two electivity indices indicated that both small (1.00 to 5.00 mm) and large (5.01 to 10.00 mm) spot larvae selected copepodid and adult copepods (stages CI to CVI), pteropods, and pelecypods. Small croaker larvae also selected copepodid and adult copepods, as did large croaker larvae. Small and large larvae of both species selected Oncaea sp. from among the copepods, while one or more length categories of either species selected Oithona spp., Paracalanus spp., Corycaeus spp., and Acartia tonsa. Selection appeared to be related not only to the width, but also to the swimming behavior and color of food organisms.

Harvey, G.R., and R.F. Lang. Dimethylsulfoxide and dimethylsulfone in the marine atmosphere. Geophysical Research Letters, 13(1):49-51 (1986).

New isolation and detection methods were developed to measure dimethylsulfoxide (DMSO) and dimethylsulfone (DMSO₂) in marine rain and marine air masses. Central equatorial Pacific rain contained 1 to 10 µg/l of each of these components. Uncontaminated air sampled off Miami contained 2-6 ng/m³ of each component. These concentrations suggest that DMSO and DMSO₂ may be as significant as dimethylsufide (DMS) in marine sulfur transport. In fact, DMSO was observed to undergo disproportionation in illuminated seawater or distilled water to DMS and DMSO₂. This latter observation implies a partially reversible loop in the sulfur transport cycle and complicates the calculation of the flux of sulfur into the marine boundary layer.

Hayes, S.P., D.W. Behringer, M. Blackmon, D.V. Hansen, N.C. Lau, A. Leetmaa, S.G.H. Philander, E.J. Pitcher, C.S. Ramage, E.M. Rasmusson, E.S. Sarachik, and B.A. Taft. The equatorial Pacific Ocean climate studies (EPOCS) plans: 1986-1988. EOS Transactions, American Geophysical Union, 67:442-444 (1986).

No abstract.

Jones, R.W. Mature structure and motion of a model tropical cyclone with latent heating by the resolvable scales. Monthly Weather Review, 114(6):973-990 (1986).

The mature structure of a model tropical cyclone is presented with emphasis on convection in the eyewall and spiral rainbands. Representative patterns of rainband activity occur during the last two days of a 13-day experiment and are shown for 288 h or day 12. These model rainbands seem to be forced by a pair of quasi-stationary spiral bands of upward motion that appear in the low troposphere and boundary layer ahead of and behind the westward moving vortex. These forcing bands, in turn, may be the result of a non-linear interaction of azimuthal wavenumber one with itself. The convective band elements ahead of the vortex do not reach the outflow layer, but are capped by a mesoscale subsidence band in the upper troposphere. Elements behind the vortex, however, reach the outflow layer and have greater precipitation intensity. During the last two days of the experiment, three times as much rain falls behind the vortex and outside of the inner core as falls in front of the vortex. The mesoscale subsidence band that caps the convection in bands in front of the vortex is the direct result of a characteristic asymmetry of the 250 mb layer. This asymmetry forms between simulation hours 60 to 84 and results from bands outside of the inner core of the vortex. The model vortex structure, in cross-section format, is compared with recent aircraft observations of strong hurricanes (Jorgensen, 1984a,b), particularly Hurricane Allen on 5 August 1980. The model data represent a time and space average with respect to real data. When this averaging is taken into account, reasonable agreement is found between the model and Allen. The model updraft maximum occurs inside of the radius of maximum wind and the precipitation maximum is located outside of the maximum wind at lower levels, in agreement with the real data. The time average motion of the vortex is compared with the mass weighted mean environment current at 990 km radius. For periods of four days or more, the vortex speed agrees with the current speed and the vortex path is mostly to the right of the environment current. For 10 h averages, vortex speed deviations <12% occur and show effects of vortex environment current interactions.

Katz, E.J., P. Hisard, J.-M. Verstraete, and S.L. Garzoli. Annual change of sea surface slope along the equator of the Atlantic Ocean in 1983 and 1984. Nature, 322(6076):245-247 (1986).

The authors describe the sea surface slope derived from three complementary methods: hydrographic stations, pressure gauges, and inverted echo sounders. The latter two have the advantage of yielding continuous time series, but depend on the hydrographic stations for an absolute reference. Together, the three provide a detailed description of the temporal variation of the sea surface slope which is then compared to a wind-stress time series. The dominant signal, in both sea slope and wind stress, is the annual cycle, although amplitude and phase vary interannually. The annual increase in sea surface slope along the equator in the western and central basins lags the onset of the southeast trade wind. During the boreal winter of 1983-1984 a strong rise in sea level occurred against the African coast, accompanied by a leveling of the sea surface to the west. At the same time, an almost complete relaxation of eastward wind stress on the equator was observed near the center of the basin.

Klinkhammer, G., H. Elderfield, M. Greaves, P.A. Rona, and T.A. Nelsen. Manganese geochemistry near high-temperature vents in the Mid-Atlantic Ridge rift valley. Earth and Planetary Science Letters, 80(3-4):230-240 (1986).

In July 1985 the first high-temperature, hydrothermal vents ever discovered on the MAR were found at 26°N (TAG). A transponder-navigated survey of a 4 x 8 km area was begun when on-board measurements of manganese revealed concentrated hydrothermal plumes in the water column comparable in size and intensity to those found over geothermal fields on the EPR. These plumes also possess anomalously high light scattering properties and anomalously warm potential temperatures. Using relay-transponder navigation with a rosette-CTD system, it was possible to sample bottom waters with temperature anomalies of several decidegrees. Samples collected near vent orifices possessed silica anomalies of up to 17 µM and dissolved manganese anomalies as large as 360 nmol/kg. These manganese and silica anomalies are linearly related and predict a Mn/Si ratio of 20 mmol/mol for these MAR vent fluids, a value essentially identical to that measured in 350°C fluid from the EPR at 21°N. The distribution of temperature anomalies in the water column over this area requires the presence of more than one active vent site. A rough estimate of the convective heat loss from this section of the MAR based on theta-z profiles is 1.2 x 10⁸ cal/s which is similar to the heat loss estimated for the vent field on the EPR at 21°N.

Krueger, S.K., R.M. Wakimoto, and S.J. Lord. Role of ice-phase microphysics in dry microburst simulations. Preprints, 23rd Conference on Radar Meteorology, Snowmass, CO, September 22-26, 1986. American Meteorological Society, Boston, JP73-76 (1986).

No abstract.

Lalou, C., G. Thompson, P.A. Rona, E. Brichet, and C. Jehanno. Chronology of selected hydrothermal Mn oxide deposits from the Trans-Atlantic Geotraverse "TAG" area, Mid-Atlantic Ridge, 26°N. Geochimica Cosmochimica Acta, 50(8):1737-1743 (1986).

Radiometric ages on discrete layers in some hydrothermally deposited Mn-oxide (birnessite) samples from the TAG hydrothermal field on the Mid-Atlantic Ridge, range from 16,000 to 4,000 years, with marked increased activity noted about 15,000 and 7,000 years ago. These observations, along with previously published data and inferences on different kinds of hydrothermal activity in the TAG field, suggest episodic, multistage hydrothermal events ranging from high temperature black smokers precipitating sulfides to low temperature events precipitating Fe and Mn oxides over this entire time range. Black smokers are presently active. The location of the various deposits on the eastern wall of the median valley at this latitude suggests that the high temperature events occur at greater depths.

Leetmaa, A. Equatorial Pacific Ocean climate studies (EPOCS) and observations of the 1982/1983 El Ni�o at 85°W. Proceedings, First International Symposium on Integrated Global Ocean Monitoring, Tallinn, USSR, October 2-10, 1983. Volume 3, 364-371 (1986).

A discussion is presented of activities and observations made during the Equatorial Pacific Ocean Climate Studies Program, investigating large scale sea surface temperature anomalies. Observations of the 1982/83 El Ni�o phenomenon in the eastern Pacific are also discussed.

Long, R.B. Inverse modeling in ocean wave studies. In Wave Dynamics and Radio Probing of the Ocean Surface, O.M. Phillips and K. Hasselmann (eds.). Plenum Press, New York, 571-593 (1986).

A fundamental description of sea state is provided by the surface wave directional spectrum. Efforts to measure the directional spectrum with in-situ instrumentation generally yield data which represent estimates of integral properties of the spectrum. Extracting an estimate of the full, two-dimensional spectrum from such data presents a typical example of the so-called "inverse problem." The problem is solved by finding a model spectrum which is statistically consistent with the observations and, at the same time, satisfies a set of externally imposed constraints required to make the problem determinate.

Marks, F.D. Three-dimensional wind structure of the eyewall of Hurricane Norbert as determined from an airborne Doppler radar. Preprints, 23rd Conference on Radar Meteorology, Snowmass, CO, September 22-26, 1986. American Meteorological Society, Boston, JP248-251 (1986).

No abstract.

Maul, G.A. Book review: "Large-Scale Oceanographic Experiments and Satellites," edited by C. Gautier and M. Fieux, D. Reidel Publishing Company. Bulletin of Marine Science, 37(3):942-943 (1986).

No abstract.

Maul, G.A. Linear correlations between Florida Current volume transport and surface speed with Miami sea level and weather during 1964-1970. Geophysical Journal of the Royal Astronomical Society, 87(1):55-66 (1986).

The 1964-1970 Florida Current data of Niiler and Richardson are examined for linear correlation with observed sea level and weather because their data provide an independent test of similar correlations reported in Maul et al. Seventy-five values of directly measured volume transport and 67 values of surface speed from Niiler and Richardson's unevenly spaced data are correlated with available daily mean values of Miami Beach sea level, Bimini sea level, Bimini-Miami Beach sea level difference, and Miami weather (barometric pressure, air temperature, and north and east components of wind speed). Statistical frequency distribution of transport and of surface speed suggest variability that is not dominated by annual and/or semiannual cycles. Volume transport is most highly correlated with Bimini minus Miami Beach sea level difference, and surface speed is most highly correlated with inverted Miami Beach sea level. Including certain weather variables, results in statistically significant improvements in linear multivariate modeling of transport and surface speed from sea level, the standard errors are �2.6 Sverdrup and �10 cm s^-1 respectively. Linear correlation coefficients and multivariate regression parameters from Niiler and Richardson's data are in agreement with those from Maul et al., except that the standard error of estimating volume transport from sea level is smaller in Maul et al., apparently because of smaller errors in the direct measurements.

Maul, G.A., and N.J. Bravo. Satellite-tracked buoys and drift cards: Description of buoy trajectories and drift card returns. In Final Report, Physical Oceanography Study of Florida's Atlantic Coast Region. OCS Study MM86-0079. Florida Institute of Oceanography, 2:253-308 (1986).

No abstract.

Maul, G.A., J.R. Proni, W.P. Dammann, C.A. Lauter, M.H. Bushnell, and D.A. Mayer. Inverted echo sounder/pressure gauge measurements under the Gulf Stream in the offing of Cape Canaveral during the Florida Atlantic Coast Transport Study (FACTS). In Final Report, Physical Oceanography Study of Florida's Atlantic Coast Region. OCS Study MM86-0079, Florida Institute of Oceanography, 2:330-382 (1986).

Three inverted echo sounder/pressure gauges (IES/PGs) were placed at depths of 140 m, 760 m, and 830 m under the Gulf Stream at latitude 29°N off the Florida Atlantic coast from December 1984 to May 1985. The IES/PGs were unusable due to excessive receiver gain. Volume backscattering from below the surface caused the circuitry to record early returns rather than those from the surface. An experiment in 215 m water depth at 27°N, from July to September 1985, successfully recorded travel times to the surface after the receiver sensitivity was reduced by 30 db. The unit, placed in 830 m water depth, recorded travel times that had a non-Gaussian distribution function, but when processed by using all burst samples in a 25-hour period, gave a 40-hour low passed signal with a net decrease in travel time proportional to an increase in dynamic height of 5 dyn-cm for the five month record. Bottom pressure at the 140 m and 830 m water depth sites had net linear drifts of -178 mb and -77 mb respectively over five months; low frequency comparisons with Florida Current transport measured at the Jupiter, FL to Settlement, Point, Bahama submarine cable were therefore excluded. Linear correlation of detrended bottom pressure at the 140 m site were r = -0.33 with similarly detrended cable transports; coherence squared above 0.65 occurred at 21, 9, and 3 days, all with a phase lag of about 245 degrees.

Mayer, D.A., and J.C. Larsen. Tidal transports in the Florida Current and its relationship to tidal heights and cable voltages. Journal of Physical Oceanography, 16(12):2199-2202 (1986).

A linear relationship between tidal height (sea level of tidal frequencies) and tidal transport near 27°N in the Straits of Florida is confirmed. Transport estimates from this relationship for the O₁ and M₂ constituents are compared with those computed from cable voltages across the Florida Current. These estimates are independent in that the weighted tidal height model (tidal-height transport relationship) was developed using collective sets of current meter and velocity profiler data obtained at different times of the year and in different locations. The cable voltages, however, were calibrated using a quasi-synoptic sectional integration of depth-averaged profiler data. Further, a means is suggested by which changes in the cable calibration can be detected.

McBride, J.L., and H.E. Willoughby. Comment: An interpretation of Kurihara and Kawase's two-dimensional tropical-cyclone development model. Journal of the Atmospheric Sciences, 43(24):3279-3283 (1986).

This comment presents a detailed examination of the published model results of Kurihara and Kawase (1985) in an attempt to clarify the role of wave-CISK in the development of tropical cyclones. Kurihara and Kawase's model simulates the development of a tropical depression, although the vertical structure differs significantly from observations. The physical roles of vertical shear and nonlinear dynamics in the development in this model are unclear. The authors propose that the nonlinear terms in the equations promote rapid growth by increasing the "inertial stiffness." A major concern, however, is that the enhanced development may occur because the nonlinear terms excite modes with high horizontal wavenumbers. These modes grow rapidly through wave-CISK. From considerations of the climatological importance of horizontal shear to tropical-cyclone development in nature, this model may be less relevant to tropical cyclogenesis than one that allows horizontal shears of the environmental flow. The authors discuss the model's response to changes in the vertical shear of the basic state, which appears to have the opposite effect in the model from what it has in nature.

Molinari, R.L. Subtropical Atlantic Climate Studies (STACS) revisited. EOS, Transactions, American Geophysical Union, 67(5):59-60 (1986).

No abstract.

Molinari, R.L., J.F. Festa, and E. Marmolejo. Heat budget and climatic atlas of the western tropical Indian Ocean and Arabian Sea during FGGE (First GARP Global Experiment) (1979). NOAA Technical Memorandum, ERL AOML-63 (PB86-193281), 80 pp. (1986).

Observations of surface oceanographic and meteorological fields collected during the first GARP Global Experiment (FGGE) in the tropical western Indian Ocean and Arabian Sea have been combined and averaged by month onto a 2° by 2° grid. Monthly distributions of sea-surface temperature, wind speed and direction, air temperature, specific humidity, and cloud cover have been generated for the period from December 1978 through November 1979. Net short-wave and long-wave radiation, and sensible and latent heat flux distributions have been generated from these surface data using the bulk aerodynamic formulas. Standard errors of the mean values have been computed along with monthly contoured plots of each oceanographic and meteorological variable.

Molinari, R.L., J.F. Festa, and J. Swallow. Mixed layer and thermocline depth climatologies in the western Indian Ocean. NOAA Technical Memorandum, ERL AOML-64 (PB87-154613), 40 pp. (1986).

Mean monthly distributions of the mixed layer depth (defined as the first depth at which the temperature is 0.5°C less than the sea-surface temperature) and thermocline depth (defined as the depth of the 20°C isotherm) are derived from data collected between 1948 and 1981. Approximately 50,000 data points are available to generate the climatologies. Amplitude and phase distributions for the annual and semi-annual signals are computed from the monthly time series. The mixed layer depth distributions are compared to the thermocline depth distributions to identify possible regions where thermocline displacements influence mixed layer displacements.

Molinari, R.L., J.F. Festa, and J. Swallow. Evolution of the near-surface thermal structure in the western Indian Ocean during FGGE (1979). Journal of Marine Research, 44(4):739-762 (1986).

The evolution of mixed layer temperature (taken as sea-surface temperature, SST) in the western Indian Ocean north of 20°S and west of 80°E during the First GARP Global Experiment (FGGE), 1979, is described and modeled. The FGGE-year development in time and space of SST is compared to the appropriate climatology. FGGE events occurred in phase with climatology, but some amplitude anomalies were observed. Heat budget computations for the surface mixed layer indicate that over 25% of the region-studied energy fluxes through the sea surface can account for 80% of the observed SST variance. South of the equator, 80% of the variance is accounted for in 36% of the area and north, only 11%. Exceptions are noted along the western boundary, in the central and eastern Arabian Sea, and in a band south of the equator between 6°S and 12°S, east of 60°E. The addition of entrainment through the base of the mixed layer improves the heat budget estimates over most of the region, in particular, along the Arabian coast. Near the northern part of the coast of east Africa, however, inclusion of the effect of horizontal advection gives more improvement. The breakdown of the heat budget computations in the central and eastern Arabian Sea and in the band south of the equator is attributed to a small signal in SST variance and few data in the regions.

Molinari, R.L., S.L. Garzoli, E. Katz, E. Harrison, P. Richardson, and G. Reverdin. A synthesis of the First GARP Global Experiment (FGGE) in the equatorial Atlantic Ocean. Progress in Oceanography, 16(2):91-112 (1986).

A synthesis of near-surface oceanographic and surface meteorological data collected during the First GARP Global Experiment (FGGE) is presented to portray the oceanic response to the seasonal wind forcing for the period December 1978 to November 1979, inclusive. Major wind events during FGGE are in phase with events given in climatology. In particular, the February-March-April relaxation and May enhancement of equatorial winds occurs within one month of the mean event. Accordingly, the oceanic responses, such as the May, June, July appearance of an equatorial cold water tongue, the acceleration of the South Equatorial Current (SEC), and the vertical displacement of the equatorial thermocline occur at the average time. Furthermore, the curl distribution in the vicinity of the North Equatorial Countercurrent (NECC) during 1979 is similar to the climatological distribution in terms of phase and amplitude, except for a westward displacement in the position of the maximum curl. As predicted from linear theory, the 1979 thermocline response across the NECC is in phase with the climatological response with a westward displacement of the maximum thermocline movement. Deeper than average equatorial thermoclines and a weaker SEC may, in part, be responsible for the anomalously warm sea-surface temperatures observed on the equator between 10°W and 30°W from June to November.

Nelsen, T.A., and J.H. Trefry. Pollutant-particle relationships in the marine environment: A study of particles and their fate in a major river-delta-shelf system. Rapports et Proces-Verbaux des Reunions Conseil International pour l'Exploration de la Mer, 186:115-127 (1986).

The Pollutant-Particle Relationships in the Marine Environment (P-PRIME) program was designed to look at the association between particles (lithogenic and biogenic) and selected heavy-metal pollutants for their source-pathway-dispersal patterns and behavior from a major United States river (Mississippi River) to the adjacent continental shelf. Data from four cruises indicate the following: (a) the river's SPM concentration varied on an hourly to seasonal scale; (b) suspended particulate matter in the study area was composed of three distinct suites: a dominant lithogenic suite and two subordinates, but distinct and seasonally variable biogenic (phytoplankton) suites; (c) in order of abundance, the offshore concentration of particulate matter is in the bottom nepheloid layer, the surface turbid layer, and the midwater region; (d) in the nearshore and midshelf zone, rapid removal of river-derived (lithogenic) particles from the water column to the underlying sediments may be "driven" by biopackaging; (e) 210 Pb sediment accumulation-rate support the rapid removal and accumulation of river-derived sediments very near the river mouth; (f) data for sediment pollutant Pb support the concept of rapid sediment burial in the nearshore zone and also indicate no losses of Pb from these particles. These findings indicate that modeling and sediment transport of river/shelf systems such as the ones described above must consider variability on the hourly to seasonal scale to provide an accurate reflection of the natural system. Because of close coupling of pollutants such as Pb with particles, even after burial, future studies of the pathways and sinks of many pollutants can be, to a first approximation, that of the river-derived particles.

Ooyama, K.V. A spectral prediction model on nested domains and its application to asymmetric flow in the hurricane boundary layer. Extended Abstracts, WMO/IUGG International Symposium on Short and Medium-Range Numerical Weather Prediction, Tokyo, Japan, August 4-8, 1986. PSMP Report Series No. 19, 451-454 (1986).

No abstract.

Ortner, P.B. Application of simple photographic techniques to zooplankton sampling and sample processing. In International Conference on Marine Science in the Arabian Sea, M.F. Thompson and G.B. Dewey (eds.), March 29-April 2, 1986. Van Nostrand Reinhold, 67-77 (1986).

Over the past few years, we have been experimenting with the use of photographic techniques to process zooplankton samples collected with traditional sampling devices and to sample the plankton in lieu of such collection systems. The basic approach is particularly suitable in situations where rapid feedback is desirable and where functional group characterization of the fauna is sufficient for the ecological objectives of a particular study. The rapidity, ease, and low cost of silhouette photography make it potentially useful to field workers with limited facilities. It will produce a permanent record of a live sample which is unobtainable at present by any other means. Most importantly, the technique is non-destructive and, if desired, the sample itself can be preserved for subsequent detailed taxonomic examination. In time it will be possible to process such photographic records entirely automatically and, even at the present time, microcomputer techniques can facilitate data analysis. The applicability of this methodology to studying the plankton of the Arabian Sea is discussed in some detail. A ship-of-opportunity program employing it and other tractable techniques is suggested which could greatly enhance our understanding of the Arabian Sea.

Palmer, D.R., P.A. Rona, and M.J. Mottl. Acoustic imaging of high-temperature hydrothermal plumes at seafloor spreading centers. Journal of the Acoustical Society of America, 80(3):888-898 (1986).

We explore the possibility of using active sonar techniques to acoustically image high-temperature "black smoker" hydrothermal plumes. We examine recent sonar images of a hydrothermal vent field at 11°N on the East Pacific Rise obtained from DSRV Alvin which may show the presence of plumes. For vent fields on the East Pacific Rise, estimates are obtained of the minimum detectable concentration of precipitates as a function of the range between the sonar and the plume boundary. These estimates are compared with measured concentrations. Some of the anticipated advantages of acoustic imaging are discussed. We conclude that acoustic imaging techniques have the potential of providing a coherent framework for point sampling of physical and chemical properties of hydrothermal plumes and for determining the dynamics of their injection into the surrounding water mass.

Peng, T.-H. Land use change and carbon exchange in the tropics: II. Estimates for the entire region--Comment. Environmental Management, 10(5):573-575 (1986).

No abstract.

Peng, T.-H. The role of the ocean in the atmospheric CO₂ problem. Science Monthly, 17(8):615-621 (in Chinese) (1986).

No abstract.

Peng, T.-H. Uptake of anthropogenic CO₂ by lateral transport models of the ocean based on the distribution of bomb-produced ¹⁴C. Radiocarbon, 28(2A):363-375 (1986).

The pattern of global water column inventories of bomb-produced ¹⁴C suggests that a sizeable portion of bomb ¹⁴C that entered the Antarctic, northern Pacific, and tropical oceans has been transported to adjacent temperate regions. Models of lateral transport of surface water in the Atlantic, Indian, and Pacific Oceans are based on this distribution pattern. Upwelling of bomb-¹⁴C-free water from below takes place in the Antarctic, northern Pacific, and tropical regions; downwelling of surface water occurs in the temperature oceans and northern Atlantic. Uptake of excess CO₂ by these models is calculated using the observed Mauna Loa pCO₂ record as an input function. Results indicate that 35% of fossil fuel CO₂ is taken up by these model oceans during the period 1958-1980. Considering the observed airborne fraction of 0.55, it appears that ca 10% of the global fossil fuel CO₂ is still missing.

Peng, T.-H., and H.D. Freyer. Revised estimates of atmospheric CO₂ variations based on tree-ring ¹³C record. In The Changing Carbon Cycle: A Global Analysis, J.R. Trabalka and D.E. Reichle (eds.). Springer-Verlag, New York, 151-159 (1986).

No abstract.

Peterson, D.H., D.R. Cayan, and J.F. Festa. Interannual variability in biogeochemistry of partially mixed estuaries: Dissolved silicate cycles in northern San Francisco Bay. Estuarine Variability, 1986:123-138 (1986).

Much of the interannual variability in partially-mixed estuaries in dissolved inorganic nutrient and dissolved oxygen patterns results from an enhancement or reduction of their annual cycle (generally via climatic forcing). In northern San Francisco Bay estuary the annual cycle of dissolved silicate supply peaks in spring and the effect of phytoplankton removal peaks in fall. Because riverine silicate sources are enhanced in wet years and reduced in dry years, the annual silicate cycle is modified accordingly. Effects of phytoplankton removal are reduced and delayed in wet years and enhanced and advanced (seen earlier) in dry years. Similar reasoning can apply to interpreting and understanding other mechanisms and rates.

Piotrowicz, S.R., D.A. Boran, and C.J. Fischer. Ozone in the boundary layer of the equatorial Pacific Ocean. Journal of Geophysical Research, 91(D12):13,113-13,119 (1986).

Shipboard (~7 m) ozone measurements made in the equatorial Pacific Ocean between 20°N and 17°S and 140°W-160°W confirm the existence of a distinct ozone minimum in the vicinity of the equator in the late spring, its decline in the summer, and its absence in autumn. This minimum could not be correlated with high biological activity in surface waters. Coincident aircraft measurements of ozone from near sea surface (50-100 m) to 2 km in altitude were made along 150°W at stations at 10°N, 0°, 5°S, and 12°S in May-June 1984. Aircraft data identified the existence of a distinct ozone maximum between the lifting condensation level (LCL) or cloud base and the trade wind inversion, with ozone mixing ratios amounting to 2-2.5 times the ozone levels in the well-mixed subcloud layer. A gradient of decreasing ozone with decreasing altitude extended from the LCL (or cloud base) to the near-surface superadiabatic region but did not include it.

Powell, M.D. Airborne Doppler radar observations in the hurricane boundary layer. Preprints, 23rd Conference on Radar Meteorology, Snowmass, CO, September 22-26, 1986. American Meteorological Society, Boston, JP260-263 (1986).

No abstract.

Reverdin, G., R.L. Molinari, and Y. Du Penhoat. Objective analysis of thermocline depth distributions obtained in the tropical Atlantic Ocean during FGGE (1979). Deep-Sea Research, Part A, 33(1):43-53 (1986).

An objective analysis algorithm is applied to subsurface temperature data collected in the tropical Atlantic Ocean from January to August 1979 to obtain maps of 20°C isotherm topography. Throughout the eight-month period anomalies were essentially aligned with the ridge-trough system characteristic of the climatological thermocline distribution in the region. The anomalies, as large as 30 m, increased the relief of the 1979 ridge-trough system relative to climatology. A simple diagnostic calculation using the results from the algorithm and surface wind data suggests that in the region of the North Equatorial Countercurrent the thermocline responds to the effects of local Ekman pumping and the divergence of geostrophic currents. Both effects are caused by the seasonally varying surface winds.

Rona, P.A. Black smokers on the Atlantic seafloor: Preliminary dive report. Deep-Sea Newsletter, 12:10-11 (1986).

No abstract.

Rona, P.A., G. Klinkhammer, T.A. Nelsen, J. H. Trefry, and H. Elderfield. Black smokers, massive sulphides, and vent biota at the Mid-Atlantic Ridge. Nature, 321(6065):33-37 (1986).

The discovery of black smokers, massive sulphides, and vent biota in the rift valley of the Mid-Atlantic Ridge demonstrates that this assemblage of hydrothermal phenomena is not limited to intermediate-to-fast-spreading oceanic ridges. Hydrothermal exchange processes may thus be important at the ridges which extend through the Atlantic Ocean and western Indian Ocean, comprising more than half of the 55,000-km global length of seafloor spreading centres.

Ross, D., L.M. Lawson, and W. McLeish. Comparisons of Hurricane Fico winds and waves from numerical models with observations from SEASAT-A. In Wave Dynamics and Radio Probing of the Ocean Surface, O.M. Phillips and K. Hasselmann (eds.). Plenum Press, New York, 595-613 (1986).

Several types of satellite data collected during SEASAT-A overpasses of Hurricane Fico are used to adjust input parameters in a hurricane wind prediction model. Derived winds are then used in a complex discrete spectral wave prediction model to calculate wave heights and directional spectrum distributions. Three different areas of the storm with winds ranging from 12 m/s to 23 m/s and hindcast wave heights varying from 4 m to 8 m were used to compare model-normalized directional wave spectra with those from SEASAT synthetic aperture radar (SAR) imagery. The two-dimensional normalized spectral energy results from the SAR and wave model showed an average difference in peak directions of 0.9° with a standard deviation of 6.8°. Wind and wave model results are also compared with altimeter data along a subsatellite track. This study shows the value of satellite observations in model, validation, and, conversely, the value of the model results in verification of the efficacy of the satellite data sets. Especially noteworthy is the snapshot view of the characteristics of the storm, a demonstration of the potential power of satellite remote sensing.

Shang, E.C., L.M. Lawson, and D.R. Palmer. Source range information loss in waveguides. Journal of the Acoustical Society of America, 79(4):958-963 (1986).

In a previous study (E.C. Shang, C.S. Clay, and Y.Y. Wang, J. Acoust. Soc. Am., 78, 172 [1985]) a new method of passive source ranging in a layered waveguide was proposed. This paper investigates the reduction (loss) in range information due to phase fluctuations and to an inaccurate description of the environment (waveguide mismatch). The effects of phase fluctuations are investigated using a two-dimensional Gaussian distribution function. A numerical normal mode code is used to study the effects of waveguide mismatching. The loss in range information caused by incorrect descriptions of both the bottom sediment type and the sound speed profile in the water column is calculated. Examples are given for a water depth of 100 m and frequencies in the range from 100-500 Hz.

Shapiro, L.J. The three-dimensional structure of synoptic-scale disturbances over the tropical Atlantic. Monthly Weather Review, 114(10):1876-1891 (1986).

Twice-daily analyses of low-level and 200-mb winds over the tropical Atlantic region, archived by the National Hurricane Center, are used to diagnose the structure of synoptic-scale disturbances in the 3-5 day period band. The large-scale disturbances, extracted by a complex empirical orthogonal function technique, are found to have a preferred shift at 200 mb relative to the low-level troughs of somewhat less than one-quarter cycle. The presentation concentrates on July 1975, during which a repeated series of strong disturbances propagated through the region. The relationship between these disturbances and systems in the eastern Pacific is discussed. An analysis of the vorticity propagation characteristics for the disturbances during the month indicates a very different balance from level to level. At the lower level, advection by the mean wind plays a major rate; at 200 mb, the meridional advection of mean vorticity is more important. Rawinsonde data from several island stations are used to resolve the vertical structure of the disturbances. After adjustment for lower density aloft, the kinetic energy at the lower and upper levels is found to be almost equal. The systems propagate westward faster than the mean zonal wind at any level, with a zonal phase speed that is relatively constant with height. It is inferred that the disturbances most likely propagate as a coherent system due to vertical coupling by convection. Evidence is found that the influence of low-level waves on the evolution of 200-mb systems may be stronger than has been previously described.

Shapiro, L.J., and D.B. Chelton. Comments on "Strategies for assessing skill and significance of screening regression models with emphasis on Monte Carlo screenings." Journal of Applied Meteorology, 25(9):1295-1298 (1986).

In a recent paper, Lanzante reviewed methods for estimating the skill and significance of screening regression models through the use of Monte Carlo simulations. The strategies reviewed have several limitations that were not specified by the author. Due to the influence of true model skill, the Monte Carlo method provides an upper bound on the expected artificial skill, not the expected artificial skill itself as assumed. Lanzante emphasizes the advantages of the use of independent (uncorrelated) predictors. However, the disadvantages of their use and the advantages of dependent predictors in a screening regression were not considered. The review of the effects of serial correlation on estimates of skill is misleading. The assertion that the formulations developed by Davis and Chelton are erroneous is incorrect. Moreover, contrary to the implication of the review, the use of effective sample size in tests of model significance has practical utility in applications including the Monte Carlo method.

Szoke, E.J., E.J. Zipser, and D.P. Jorgensen. A radar study of convective cells in mesoscale systems in GATE, Part I: Vertical profile statistics and comparison with hurricanes. Journal of the Atmospheric Sciences, 43(2):182-198 (1986).

This is Part I of a two-paper describing the structure of the vertical profile of radar reflectivity in convective cells which are of part of mesoscale convective systems in GATE. Earlier work has established that characteristic mean vertical velocities in such convective clouds in GATE were rather weak, <3-5 m s^-1. The microphysical implications of the weak updrafts have been proposed to include the rarity of large particles above the freezing level. As a working hypothesis for these papers it is proposed that cells with weak updrafts have characteristic vertical reflectivity profiles exhibiting modest reflectivities at low levels, and decreasing rapidly with height above the freezing level. Vertical radar reflectivity profiles are compiled from 296 convective cells having at least 40 dBZ surface reflectivity, and it is found that the profiles are consistent with the above reasoning. The mean profile is of modest strength, 45 dBZ echo at the surface and a 20 dBZ echo top of 8.2 km, and the reflectivity decreases rapidly with height above the freezing level. Statistics of surface reflectivity, echo top, and height of the maximum echo aloft all lend support to the above picture of the GATE cell. The GATE radar profiles are similar to mature hurricane radar profiles, consistent with their updraft velocities being weak as well. In contrast the GATE profiles are markedly weaker than profiles from continental thunderstorm cells, consistent with the much higher vertical velocities in the continental cells.

Thacker, W.C. Anomalous dispersion in numerical models of wave spectra. Proceedings, Symposium on Wave Dynamics and Radio Probing of the Ocean Surface, Miami, FL, May 13-20, 1981. Inter-Union Commission on Radio Meteorology, 661-669 (1986).

No abstract.

Thacker, W.C. Relationships between statistical and deterministic methods of data assimilation. Proceedings, International Symposium on Variational Methods in Geosciences, Norman, OK, October 15-17, 1985. Elsevier Science Publishers B.V., 173-179 (1986).

Fitting dynamics to meteorological data in the least squares sense can yield the same analysis as Kalman filtering when both methods use precisely the same information.

Trefry, J.H., T.A. Nelsen, R.P. Trocine, S. Metz, and T.W. Vetter. Trace metal fluxes through the Mississippi River delta system. Rapports et Proces-Verbaux des Reunions Conseil International pour l'Exploration de la Mer, 186:277-288 (1986).

River deltas serve as an important sink for many continentally-derived contaminants, thereby restricting their flux through the coastal zone. We have investigated the geochemical cycling of several trace metals, especially Cd, Mn, and Pb, in the Mississippi River delta-Gulf of Mexico system to establish the efficiency of this deltaic sink. Greater than 90% of the Mississippi River trace metal load is associated with detrital particles. As a result, dissolved metal concentrations are very low and appear to be controlled in several instances by a predictable partitioning between dissolved and particulate phases. To model this partitioning, distribution coefficients (K_d) were calculated for several metals using field and laboratory data. Much of the river-borne sediment is deposited within 30-50 km of the river mouth. This is especially evident in the sediment record for Pb which shows a sharp decrease in the depth to which pollutant Pb is found with increasing distance offshore. Sediment Pb profiles and river particulate Pb concentrations also support a 40% decrease in the 1982-1983 Mississippi River burden of pollutant Pb relative to the mid-1970's. Delta sediments are not always the ultimate sink for trace metals. Remobilization of Mn and Cd to the overlying water column leads to a 10-50% net loss of these metals from the sediment. In contrast, the Pb cycle shows rapid, permanent removal to the sediments. The Mississippi delta is thus a near-perfect filter of Pb, and traps much, but not all, of the incoming fluxes of Cd and Mn. The availability and potential reactivity of sediment trace metals were elevated by leaching sediments with a series of buffers at pH 2.2-6.0. Results show that Cu, Fe, and Pb have a much lower tendency towards removal than Cd and Mn.

Vincent, C.E., D. Hanes, T. Tamura, and T.L. Clarke. The acoustic measurement of suspended sand in the surface zone. Proceedings, International Conference on Measuring Techniques of Hydraulics Phenomena in Offshore, Coastal, and Inland Waters, London, England, April 9-11, 1986. British Hydromechanics Research Association, 443-451 (1986).

No abstract.

Williams, A.B., and P.A. Rona. The new caridean shrimps (Bresiliidae) from a hydrothermal field on the Mid-Atlantic Ridge. Journal of Crustacean Biology, 6(3):446-462 (1986).

Rimicaris, a new genus, and two new species of caridean shrimps, R. Exoculata and R. Chacei, are recorded in swarms from a thermally-influenced site in the rift valley of the Mid-Atlantic Ridge at 26°08.3'N, 44°49.6'W, 3,620-3,650 m depth. The shrimps appear to be the predominant macroinvertebrates in heated waters (at least 1.0°C above ambient, 2.37°C away from vents) on black sediments and layered rocks with the appearance of polymetallic sulfides precipitated from black smoker-type vents. Characters of these species indicate placement in the family Bresiliidae which is distributed in surface to mid-ocean depths. A key to the seven bresiliid genra is given.

Willis, P.T. Characteristics of hurricane melting layers. Preprints, 23rd Conference on Radar Meteorology, Snowmass, CO, September 22-26, 1986. American Meteorological Society, Boston, JP264-267 (1986).

No abstract.

Woodward, W.E., G.A. Maul, W. McLeish, S.R. Baig, R.D. Crissman, D.E. Barrick, G.D. Garrett, and K. Nancarrow. CODAR operations in the Straits of Florida. Proceedings, Oceans '86 Conference, Washington, D.C., September 23-25, 1986. Institute of Electrical and Electronic Engineers, 421-425 (1986).

No abstract.

Zhang, J.-Z., and M. Whitfield. Kinetics of inorganic redox reactions in seawater. Marine Chemistry, 19:121-137 (1986).

The kinetics of the reaction between iodate and bisulfide ions have been considered in seawater over a range of reactant concentrations and at temperatures from 5 to 35°C. The progress of the reaction in a closed vessel was monitored by the potentiometric measurement of pH and pS^2-. In a series of experiments at reagent concentrations approaching those observed in natural systems, samples were drawn off from the closed vessel at regular intervals for polarographic analysis of iodate, [IO₃^-], and total sulfide [S_T]. The stoichiometric measurements, together with observations on the products formed, indicate that the initial reaction is:

5HS^- + 2IO₃^- + 7H⁺ <--> I₂ + 5S + 6H₂O

Measurements using both the potentiometric and polarographic data at constant initial pH suggest an initial rate equation of the form:

(d[S_T]₀/dt)₀ = k' [IO₃^-]₀^0.5 [S_T]₀

At 25°C, pH 8.2 and a salinity of 35 ^o/_oo, potentiometric measurements give k' = 162 mol^-1 min^-1 and polarographic measurements give k' = 105 mol^-1 min^-1. The reaction proceeds more rapidly than the corresponding reaction of bisulfide ions with molecular oxygen and it should, therefore, provide a significant source of molecular iodine in circumstances where oxic and anoxic waters mix (e.g., when estuarine sediments are tidally stirred or during the intermittent seasonal mixing of stratified fjord or lake systems).

**1985**

Apel, J.R., J.R. Holbrook, A.K. Liu, and J.J. Tsai. The Sulu Sea Internal Soliton Experiment. Journal of Physical Oceanography, 15(12):1625-1651 (1985).

We present the results of a comprehensive study of large-amplitude internal solitons generated in the Sulu Sea in the Philippines by intense tidal flow over a sharp bathymetric feature. Surface signatures of these waves have been observed in images from the DMSP, Landsat, and Nimbus-7 satellites and the space shuttle SIR-A synthetic aperture radar. A two-week experiment was conducted in the Sulu Sea in May 1980 from R/V Oceanographer, during which a three-mooring phased array of current meters and thermistors was implanted near the wave source and at 82 km and 200 km from the source. Seventeen soliton packets were observed whose properties underwent significant change as they propagated across the sea. Vertical profiles of density, temperature, and acoustic backscatter, as well as radar and photographic surface signatures, were obtained from the ship. Data from satellites, moorings, and the ship give unprecedented information on the spatial and temporal characteristics of solitary waves, which have amplitudes as large as 90 m, wavelengths up to 16 km, periods approaching 1 hour, crest lengths in excess of 350 km, and lifetimes greater than 2.5 days. Phase speeds are near 2.5 m s^-1, well above computed linear values. The solitons are accompanied by narrow stripes of breaking surface waves 1000 m wide, with heights on the order of 1 m. The waves occur in groups containing several solitons, with groups separated by 12.5- and 25-hour tidal intervals, and appear and disappear over a fortnightly cycle. The theory of solitary-wave evolution has been used to interpret the observations with the evolution equation being solved using pseudospectral technique and good agreement is obtained between theory and experiment. From an observed initial disturbance, the calculation reproduces the measurements at the distant mooring with respect to number, speed, and spacing; amplitudes and widths depend on factors not currently in the theory.

Benggio, B.L., and T.A. Nelsen. Technical note: Successful instrument array deployments in soft mud bottoms adjacent to the Mississippi Delta. Applied Ocean Research, 7(1):58-60 (1985).

An anchor design for instrument arrays was developed for use in the very soft muddy sediments adjacent to the Mississippi Delta. Because of the low sediment shear strengths and high sensitivities combined with large dynamic loadings due to strong currents, problems in successful deployments and recoveries were anticipated. A total of six deployments were attempted; four were sediment trap arrays and two were current meter/transmissometer arrays. All six deployments and recoveries were successful. The array design presented herein is a safe, easy, and cost effective method for deploying instrument arrays in areas where soft bottoms and strong currents are a consideration.

Bennett, R.H., S.A. Bush, L. Lehman, B. Gritton, E.B. Forde, G.R. Harvey, W.B. Sawyer, and M.H. Hulbert. Organic carbon and submarine sediment, geotechnical property interrelations. Marine Geotechnology, 6(1):61-98 (1985).

Total organic carbon content (TOC) and selected geotechnical properties were measured in submarine sediments of the U.S. central east coast and the Mississippi Delta. TOC values in the near-surface Delta sediments were approximately 1% (dry weight). TOC in surficial sediments from the U.S. east coast outer continental shelf upper slope, and upper rise was generally less than 1%, but between the upper slope and the upper rise, values ranged from 1% to 3% and exceeded 3% in patches associated with Norfolk and Washington Canyons. TOC displayed positive linear correlations with water content, liquid limit, plastic limit, plasticity index, and the amount (percent) of fine-grained material. Nevertheless, there appeared to be no strong dependence of geotechnical properties on TOC in these sediments. This was in accord with previously reported studies on terrestrial soils with TOC values of less than 5%. Carbohydrate content was strongly correlated with water content and plasticity index, suggesting that measurement of individual components of the organic material may provide more sensitive indications of the effects of organics on geotechnical properties than measurement of bulk TOC. Selected geotechnical properties and TOC content of U.S. continental margin surficial sediments displayed regional trends related to water depth and morphological setting. These trends are probably related to recent biological, sedimentological, and oceanographic processes active on the outer shelf, slope, and rise.

Bitterman, D.S. Use of ARGOS tracked drifting buoys in the equatorial Pacific Ocean. Proceedings, 1984 Drifting Buoy Workshop, Bay St. Louis, MS, November 1984. Marine Technology Society, Gulf Coast Section, 109-111 (1985).

No abstract.

Black, P.G., R.L. Elsberry, L.K. Shay, and R.M. Partridge. Hurricane Josephine (1984) surface winds and ocean response determined from air-deployed drifting buoys and concurrent research aircraft data. Extended Abstract Volume, 16th Conference on Hurricanes and Tropical Meteorology, Houston, TX, May 14-17, 1985. American Meteorological Society, Boston, 22-24 (1985).

No abstract.

Black, P.G., R.C. Gentry, V.J. Cardone, and J. Hawkins. SEASAT microwave wind and rain observations in severe tropical midlatitude marine storms. In Advances in Geophysics, Volume 27, 197-277 (1985).

This overview presents initial results of studies concerning Seasat measurements in and around tropical and severe midlatitude cyclones over the open ocean and provides an assessment of their accuracy and usefulness. Sensors flown on Seasat provided complementary measurements of surface wind speed direction, rainfall rate, significant wave height and wave length, and sea surface temperature. These measurements were made with the Seasat-A Satellite Scatterometer (SASS), the Scanning Multichannel Microwave Radiometer (SMMR), The Seasat altimeter, and the Seasat Synthetic Aperture Radar (SAR). This is the first time that such a sophisticated array of microwave instruments has been used to study tropical cyclones.

Broecker, W.S., T.-H. Peng, and T. Takahashi. Reconstructions of past atmospheric CO₂ content from the chemistry of the contemporary ocean: An evaluation. DOE Technical Report TR020, DOE/OR-857 (1985).

No abstract.

Broecker, W.S., C. Rooth, and T.-H. Peng. Ventilation of the deep northeastern Atlantic. Journal of Geophysical Research, 90(C4):6940-6944 (1985).

Comparison of the 1973 GEOSECS expedition results from the deep eastern basin of the North Atlantic with those for 1981 TTO expedition reveal no firm evidence for change in NO₃, PO₄, or a H₄SiO₄ concentration. While a 2-3 µmol/kg difference is seen for O₂, it is more likely experimental than temporal in origin. The combined TTO-GEOSECS data sets reveal no evidence for ventilation of the bottom waters of the eastern basin by waters from the north.

Broecker, W.S., T.-H. Peng, G. Ostlund, and M. Stuiver. The distribution of bomb radiocarbon in the ocean. Journal of Geophysical Research, 90(C4):6953-6970 (1985).

Water column inventories are calculated for bomb radiocarbon at all the stations occupied during the GEOSECS and NORPAX expeditions and for the available TTO stations. The pattern of global inventories obtained in this way suggests that a sizable portion of the bomb radiocarbon that entered the Antarctic, the northern Pacific, and the tropical ocean has been transported to the adjacent temperature zones. A strategy for utilizing these inventory anomalies as constraints on global ocean circulation models is presented. Essential to this strategy are the improvement of our knowledge of the pattern of wind speed over the ocean, the establishment of the wind speed dependence of the rate of gas exchange between the atmosphere and sea, and the continued mapping of the distribution of bomb-produced radiocarbon in the sea.

Burpee, R.W., R.E. Kohler, and D.G. Marks. An evaluation of Omega dropwindsonde data in track forecasts of Hurricane Josephine. Extended Abstracts Volume, 16th Conference on Hurricanes and Tropical Meteorology, Houston, TX, May14-17, 1985. American Meteorological Society, Boston, 162-163 (1985).

No abstract.

Carsey, T.P. Quantitation of vanadium oxides in airborne dusts by x-ray diffraction. Analytical Chemistry, 57:2125-2130 (1985).

No abstract.

Chew, F., J.M. Bane, and D.A. Brooks. On vertical motion, divergence, and the thermal wind balance in cold-dome meanders: A diagnostic study. Journal of Geophysical Research, 90(C2):3173-3183 (1985).

Wavelike meanders are observed along the length of the Florida Current from the Florida Keys to Cape Hatteras. These propagating meanders are three-dimensional; each has a cold dome; and the meandering flow that overtakes the dome in a cyclonic turn is characteristically stronger when flowing offshore than when flowing onshore. The authors focus on vertical motion as a key to understanding the interdependence of the downstream propagation, the upwelling in the cold dome, and the skewness in the strength of the meandering flow.

Clarke, T.L., S. Alper, J.R. Proni, and L. Huff. A definition of "ocean bottom" and "ocean bottom depth." Proceedings, Oceans '85 Conference, San Diego, CA, November 12-14, 1985. Institute for Electrical and Electronic Engineers, Volume 2, 1212-1215 (1985).

The question of the definition of "ocean bottom" for charting and other purposes has been discussed for many years. Intimately associated with the question of the definition of "ocean bottom depth," acoustical echo-sounding has been the dominant approach in making bottom depth estimates. NOAA has undertaken an applied research program to determine the maximum information content available in an acoustical echo from an ocean bottom which may be used to characterize that bottom in terms of texture, particulate type and engineering properties such as the shear modulus of elasticity; the resulting information to be analyzed and synthesized resulting in a scientific/engineering based definition of "bottom" or "bottom-depth." Results shall be presented from a computer model of acoustic information from different bottom types, e.g., of varying surface roughness, porosity, and so on. Initial model data indicate that with appropriate choices of acoustic frequency, bottom-roughness scattering can be less than bottom volumetric scattering, thereby allowing inferences of bottom characterization and engineering parameters.

Cornuelle, B., C. Wunsch, R. Heinmiller, D.W. Behringer, T. Birdsall, K. Metzger, M. Brown, R. Knox, W. Munk, P. Worcester, J. Spiesberger, R. Spindel, and D. Webb. Tomographic maps of the ocean mesoscale. Part I: Pure acoustics. Journal of Physical Oceanography, 15(2):133-152 (1985).

A field test of ocean acoustic tomography was conducted in 1981 for a two month period in a 300 km square at 26°N, 70°W in the North Atlantic (just south of the MODE region). Nine acoustic deep-sea moorings with sea floor transponders for automated position keeping and with provisions for precise time keeping were set and recovered. From the measured travel times between moorings, various displays of the three-dimensional field of sound speed (closely related to temperature) have been obtained by inversion procedures. These procedures use historical ocean data as a reference, but all information from the in situ surveys has been withheld; the "pure" tomographic results were then compared to direct in situ observations. The tomographically derived spatial mean profile compares favorably to an equivalent profile from the in situ observations; both differ significantly from the historical average. Maps constructed at three day intervals for a two-month period show a pattern of eddy structure in agreement with the direct observations within computed mapping errors, but these mapping errors are too large for many oceanographic purposes. The mapping errors are the result of an unexpectedly large noise variance in travel time. (A 1983 experiment, using sources with larger bandwidth, reduced this variance to acceptable limits.) The 1981 tomographic results strongly suggest that the ocean sometimes undergoes transitions too rapid to be mapped over such large areas by shipboard observations.

Dodge, P.P., R.W. Burpee, and F.D. Marks. Convective-scale and mesoscale structure of hurricanes during landfall. Extended Abstracts Volume, 16th Conference on Hurricanes and Tropical Meteorology, Houston, TX, May 14-17, 1985. American Meteorological Society, Boston, 7-8 (1985).

No abstract.

Emanuel, W.R., I. Y.-S. Fung, G.G. Killough, B. Moore, and T.-H. Peng. Modeling the global carbon cycle and changes in the atmospheric CO₂ levels. In Atmospheric Carbon Dioxide and the Global Carbon Cycle, J.R. Trabalka (ed.). DOE/ER-0239, 141-174 (1985).

No abstract.

Franklin, J.L., and P. Julian. An investigation of Omega windfinding accuracy. Journal of Atmospheric and Oceanic Technology, 2(2):212-231 (1985).

The major sources of error in Omega-derived wind estimates are examined and illustrated. Sample dropwindsondes and local Omega signals are used to illustrate the effects of several types of phase propagation anomalies. A stationary test sonde and synthetic Omega phases are used to determine the accuracy of three Omega phase-smoothing algorithms and their associated error estimates and to determine the impact of base station motion for sondes released from aircraft. Omega windfinding errors can be classified as either "internal" or "external" errors. Internal errors are associated with signal quality and transmitter-sonde geometry, while external errors are caused by anomalous phase propagation. Estimates of wind error (wind uncertainties) are provided by the equations of Omega windfinding. These uncertainties, however, estimate only the effects of internal errors. Precise assessment of errors caused by anomalous phase propagation requires the measurement of phase data by a stationary receiver. Such measurements show that errors from external sources range from about 1 m s^-1 for diurnal changes in ionospheric height to 20-30 m s^-1 for sudden ionospheric disturbances. Methods for dealing with these problems in sonde postprocessing are described. Data from a stationary test sonde show that the effect of aircraft maneuvers on real-time Omega wind estimates is substantial; during turns, errors in real-time wind estimates increase by over 50%. The comparison of phase-smoothing algorithms shows that cubic-spline smoothing produces wind estimates 20-50% more accurate than those obtained with other methods. Hence, it is recommended that this smoothing algorithm be used in dropwindsonde postprocessing. It is estimated that such postprocessing will reduce errors by 60% during aircraft turns and by 30% at other times.

Franklin, J.L., S.J. Lord, L.J. Shapiro, and K.V. Ooyama. An objective analysis of Omega dropwindsonde data from Hurricane Debby (1982). Extended Abstracts Volume, 16th Conference on Hurricanes and Tropical Meteorology, Houston, TX, May 14-17, 1985. American Meteorological Society, Boston, 186-187 (1985).

No abstract.

Friedman, H.A. Educational program encourages students to seek hurricane precautions (instructional programs to encourage family involvement). In Hurricane Awareness Workbook: Perspectives on Hurricane Preparedness (a monograph). Federal Emergency Management Agency/National Oceanic and Atmospheric Administration, Washington, D.C., A27-A28 (1985).

No abstract.

Friedman, H.A. Meteorological education as a window on science and technology: Activities of the AMS Board of School and Popular Meteorological and Oceanographic Education. Proceedings, First International Conference on School and Popular Meteorological Education, Oxford, England, July 2-4, 1984. Royal Meteorological Society, 6-9 (1985).

Many U.S. scientists and educators have long held the belief that our educational system has failed to provide its students with the mathematics and science skills needed to compete successfully in today's technologically-oriented society or to maintain our nation's position of technological leadership in the world. Only recently has this belief motivated members of the meteorological profession, through the American Meteorological Society (AMS) and other scientific organizations, to undertake a number of educationally-related activities designed to reverse the disturbing trend toward math and science illiteracy in the nation's schools. The Board of School and Popular Meteorological and Oceanographic Education (BSPMOE) has joined with other boards of the AMS Education and Manpower Commission to develop a resource guide for use with school-aged children and the general public. The guide is designed to help promote an awareness of meteorology as a science and the importance of "weather" in everyday life. We believe that such awareness will serve as a "window" on mathematics, science, and technology, especially for school-aged children, and will awaken their scientific curiosity, enhance their scientific literacy, and heighten their enthusiasm for continued learning. The activities, accomplishments, and programmatic goals of the BSPMOE are discussed.

Friedman, H.A. School-based and community-wide education and public information programs to increase tropical cyclone awareness and preparedness. Proceedings, First International Conference on School and Popular Meteorological Education, Oxford, England, July 2-4, 1984. Royal Meteorological Society, 79-85 (1985).

Education and public information are recognized as critical elements in the design, organization, and implementation of effective tropical cyclone warning systems. Decision-makers and citizens must have a clear understanding of the dangers associated with tropical cyclones. Otherwise, even in nations that have a high level of preparedness, citizens are likely to take all measures necessary to protect themselves, or to mitigate against, the destructive effects of future landfalling storms. In response to this recognition, a numer of education, public information, and preparedness programs have been proposed or are now in progress. The goals and strategies of three such programs, namely, (1) a cognitive and effective learning model (CALM), to create an awareness of the hurricane problem in at-risk coastal communities of south Florida (HRD/AOML-NOAA), (2) Pan Caribbean Disaster Preparedness and Prevention Project (CARICOM, UNDRO, WHO), and (3) Tropical Cyclone Programme Project No. 14: Public Information and Education (WMO, UNDRO, LRCS), are discussed in this paper. These efforts represent, respectively, programs with local, regional, and international focus.

Friedman, H.A., P. Stephens, J. Williams, and O.E. Thompson. Guide to Establishing School and Public Educational Activities. First edition (limited distribution), American Meteorological Society, Boston, 21 pp. (1985).

The first edition of this guide to local AMS chapters and university departments is designed to help develop school and public educational outreach programs in their communities. The guide was produced cooperatively by the AMS Board of School and Popular Meteorological and Oceanographic Education and the Board on Women and Minorities. The authors invite readers of this document to comment on its usefulness in conducting and implementing community educational outreach programs. Formal publication of the guide is planned.

Garzoli, S.L., and S.G.H. Philander. Validation of an equatorial Atlantic simulation model using inverted echo sounder data. Journal of Geophysical Research, 90(C5):9199-9201 (1985).

No abstract.

Goldenberg, S.B., S.D. Aberson, and R.E. Kohler. Incorporation of Omega dropwindsonde data into SANBAR: An operational barotropic hurricane-track forecast model. Extended Abstracts Volume, 16th Conference on Hurricanes and TropicalMeteorology, Houston, TX, May 14-17, 1985. American Meteorological Society, Boston, 44-45 (1985).

No abstract.

Govoni, J.J., A.J. Chester, D.E. Hoss, and P.B. Ortner. An observation of episodic feeding and growth of larval Leiostomus xanthurus in the northern Gulf of Mexico. Journal of Plankton Research, 7(1):137-146 (1985).

Four cruises were conducted in the northern Gulf of Mexico over two spawning seasons of the sciaenid fish Leiostomus xanthurus. On only one occasion did unusually high densities of larvae and their principal microzooplanktonic foods co-occur. Peak densities of larvae and microzooplankton were observed in a thin lens of cool surface water that characterized a hydrographic discontinuity, and all larvae contained high numbers of food organisms in their guts. Instantaneous exponential growth rates, estimated from measurements of otolith growth increments, indicated accelerated growth on the day that larvae were collected. A laboratory experiment verified that larval L. xanthurus responds to an increased ration with accelerated growth that is detectable in otoliths. Together these data suggest that the spatial distribution of L. xanthurus larvae and their microzooplanktonic food is patchy and that interactions of larvae and microzooplankton may be episodic.

Greenwood, J.A., V.J. Cardone, and L.M. Lawson. Intercomparison test version of the SAIL wave model. In Ocean Wave Modeling. Plenum Press, New York, 221-233 (1985).

No abstract.

Hansen, D.V. Eastern tropical Pacific thermocline topography during 1982-1983. In El Niño Atlas, 1982-1983, A. Leetmaa and J. Witte (eds.), Chapter 12, U.S. Government Printing Office, 131-134 (1985).

No abstract.

Hansen, D.V. Oceanographic variations in the eastern and central Pacific Ocean during the El Niño phenomenon of 1982-1983. Proceedings, Regional Seminar Science Technology and Environmental Aggression: El Niño Phenomenon, Lima, Peru, June 4-8, 1984. National Council for Science and Technology, 149-166 (1985).

No abstract.

Hansen, D.V., M.C. Pazos, and R. Allen. Movements of satellite-tracked drifting buoys in the eastern equatorial Pacific during 1982-1983. In El Niño Atlas, 1982-1983, A. Leetmaa and J. Witte (eds.), Chapter 8, U.S. Government Printing Office, 89-102 (1985).

No abstract.

Harvey, G.R., and D.A. Boran. Geochemistry of humic substances in seawater. In Humic Substances in Soil, Sediment, and Water: Geochemistry, Isolation, and Characterization, G.R. Aiken, D.M. McKnight, R.L. Wershaw, and P. MacCarthy (eds.). John Wiley and Sons, New York, 233-247 (1985).

Marine humic substances have received very little attention because of their low concentration in seawater and the difficulties associated with obtaining enough sample for study. Recent developments have allowed gram quantities to be isolated conveniently. Seawater fulvic and humic acids have now been isolated from several diverse environments and in different seasons of the year. Spectral, chemical, and physical studies indicate that seawater humic substances are very similar wherever they are formed. Based on these observations a hypothesis proposed: seawater humic substances are derived from the free radical cross-linking of unsaturated lipids released into the water column. The hypothesis has been tested by laboratory synthesis by the proposed pathway and by correctly predicting the results of several chemical and biological reactions. A few problems with the structure still remain. The percent hydrogen is too low, the functionality of the nitrogen is not known, and there is more 13-C in the humic substances than in the starting lipids.

Harvey, G.R., J.S.S. Damste, and J.W. De Leeuw. On the origin of alkylbenzenes in geochemical samples. Marine Chemistry, 16(2):187-188 (1985).

No abstract.

Hendee, J.C., and G. Mueller. Histology of the adenohypophysis of the kelp greenling, Hexagrammus decagrammus (Hexagrammidae). Journal of Fisheries Biology, 27(3):273-276 (1985).

No abstract.

Houze, R.A., F.D. Marks, R.A. Black, P.T. Willis, and J.F. Gamache. Airborne Doppler radar and cloud microphysical measurements in Hurricane Norbert.Extended Abstracts Volume, 16th Conference on Hurricanes and Tropical Meteorology, Houston, TX, May 14-17, 1985. American Meteorological Society, Boston, 5-6 (1985).

No abstract.

Jorgensen, D.P., E.J. Zipser, and M.A. LeMone. Vertical motions in intense hurricanes. Journal of the Atmospheric Sciences, 42(8):835-856 (1985).

Hurricane vertical motion properties are studied using aircraft-measured 1 Hz time series of vertical velocity obtained during radial penetrations of four mature hurricanes. A total of 115 penetrations from nine flight sorties at altitudes from 0.5 to 6.1 km are included in the data set. Convective vertical motion events are classified as updrafts (or downdrafts) if the vertical velocity was continuously positive (or negative) for at least 500 m and exceed an absolute value of 0.5 m s^-1. Over 3000 updrafts and nearly 2000 downdrafts are included in the data set. A second criteria was used to define stronger events, called cores. This criteria required that upward (or downward) vertical velocity be continuously greater than an absolute value of 1 m s^-1 for at least 500 m. The draft and core properties are summarized as distributions of average and maximum vertical velocity, diameter, and vertical mass transport in two regions: eyewall and rainband. In both regions updrafts dominated over downdrafts, both in number and mass transport. In the eyewall region, the draft and core strength distributions were similar to data collected by aircraft in GATE cumulonimbus clouds. Unlike GATE clouds, however, the largest updraft cores (larger than 90% of the distribution) were over twice as large and transported twice as much mass as did the corresponding GATE updraft cores. Eyewall ascent was highly organized in a channel several kilometers wide located a few kilometers radically inward from the radius of maximum tangential wind. As in GATE, the strongest hurricane updraft cores were weak in comparison with the strongest updrafts observed in typical midlatitude thunderstorms. Mean eyewall profiles of radar reflectivity and cloud water content are discussed to illustrate the microphysical implications of the low updraft rates.

Klinkhammer, G., P.A. Rona, M. Greaves, and H. Elderfield. Hydrothermal manganese plumes in the Mid-Atlantic rift valley. Letters to Nature, 314(6015):727-731 (1985).

The concentration of dissolved manganese in seawater can be used as a chemical tracer of hydrothermal activity on the underlying seafloor. Here we present vertical profiles of seawater manganese concentrations above the rift valley of the Mid-Atlantic Ridge (MAR). The values obtained indicate the presence of plumes that are presently active generated by hydrothermal vents in the rift valley. These plumes are confined to the rift valley and do not spill over into the adjacent deep ocean basins. Differences between them suggest that there are at least five hydrothermal sources along this 1,700-km-long section of mid-ocean ridge.

Lawson, L.M., D.A. Seem, D.R. Palmer, and Y.-H. Daneshzadeh. A computer code for calculating acoustic ray paths with application to the Straits of Florida. NOAA Technical Memorandum, ERL AOML-62 (PB86-158391), 148 pp. (1985).

Ocean acoustic tomography is an attractive candidate for monitoring the heat transport in the Florida Current. The feasibility of this application of tomography depends on the ability to identify individual ray paths. Although experience shows that paths can be identified with deep ocean propagation, the ray path structure in the Florida Straits is quite different. There the sound speed is such that a ray path which travels a modest distance necessarily experiences bottom bounces. To investigate the question of ray path identification, a fast, specialized ray-tracing program was developed. Using this code, we analyzed the fluctuations in ray path geometry resulting from small perturbations in the bathymetry. This report describes the computer code, documents the historical data, and the numerous ray-tracings calculated for the Florida Straits.

Leetmaa, A. Hydrographic conditions along 85°W and 5°S and 10°S. In El Ni�o Atlas, 1982-1983, A. Leetmaa and J. Witte (eds.). Chapter 10, U.S. Government Printing Office, 107-124 (1985).

No abstract.

Leetmaa, A., and W.D. Wilson. Ametek-Straza data from the eastern Pacific. In El Niño Atlas, 1982-1983, A. Leetmaa and J. Witte (eds.), Chapter 13, U.S. Government Printing Office, 135-148 (1985).

No abstract.

Leetmaa, A., and W.D. Wilson. Characteristics of near surface circulation patterns in the eastern equatorial Pacific. Progress in Oceanography, 14:339-352 (1985).

Since June 1981 several CTD and velocity profiler sections have been made across the equator at 85°W as part of the Equatorial Pacific Ocean Climate Studies (EPOCS). Two of these sections, those in June 1981 and December 1982, are discussed in order to characterize the circulation patterns that occur when the ocean is forced by meridional wind stress. In this area the winds are predominantly southerly. Use of an Ametek-Straza acoustic Doppler backscatter profiler during the 1982 cruise gave velocity data to a depth of 270 m every 5.5 km along the shiptrack. This allowed the shear and velocity fields to be examined in greater detail than had been possible before. Large areas had shears greater than 0.01 s^-1 were observed. Greatest shears tended to coincide with regions of large vertical density gradients. Comparisons with geostrophic computations suggest that a large fraction of the shear was geostrophic. Richardson number computations indicated that over 40% of the area sampled by theCTD casts had values of less than 1 and about 5% had values less than one quarter. Values of less than one quarter were concentrated in the mixed layer but were not confined to it. Below the mixed layer, regions with low Richardson number were associated with regions where the vertical density gradient was quasi-linear. Since such regions were not confined to the vicinity of the equator, these observations suggest shear mixing as an important mechanism over large areas of the upper ocean. Within the top 40 m of the water column there was a general tendency for motions in the mixed layer to be to the left of the wind in the southern hemisphere and to the right in the northern hemisphere. However, no clear examples were found of Ekman spirals. Most of the veering was confined to the mixed layer which was of relatively constant depth over the whole survey area. South of the equator a large fraction of the shear across the base of the mixed layer appeared to be geostrophic, whereas north of the equator, these shears were ageostrophic. Estimates of the various terms in the momentum equation in the upper ocean indicated that near the equator non-linear effects, such as upwelling and northward advection, were as important as Coriolis forces, pressure gradients, and wind stress. The pressure gradient, integrated over the depth quarter, were concentrated in the mixed layer but were not confined to it. Below the mixed layer, regions with low Richardson number were associated with regions where the vertical density gradient was quasi-linear. Since such regions were not confined to the vicinity of the equator, these observations suggest shear mixing as an important mechanism over large areas of the upper ocean. Within the top 40 m of the water column there was a general tendency for motions in the mixed layer to be to the left of the wind in the southern hemisphere and to the right in the northern hemisphere. However, no clear examples were found of Ekman spirals. Most of the veering was confined to the mixed layer which was of relatively constant depth over the whole survey area. South of the equator a large fraction of the shear across the base of the mixed layer appeared to be geostrophic, whereas north of the equator, these shears were ageostrophic. Estimates of the various terms in the momentum equation in the upper ocean indicated that near the equator non-linear effects, such as upwelling and northward advection, were as important as Coriolis forces, pressure gradients, and wind stress. The pressure gradient, integrated over the depth of the mixed layer, was larger than the stress in the vicinity of the equator and the relative importance of other terms varied from place to place. The horizontal scale of variation was as small as 10 km. Near surface upwelling occurred in shallow cells with horizontal dimensions of 100 km or less.

Lewis, J.M., C.M. Hayden, C.S. Velden, T.R. Stewart, S.J. Lord, S.B. Goldenberg, and S.D. Aberson. The use of VAS winds and temperatures as input to barotropic hurricane-track forecasting. Extended Abstracts Volume, 16th Conference on Hurricanes and Tropical Meteorology, Houston, TX, May 14-17, 1985. American Meteorological Society, Boston, 40-41 (1985).

No abstract.

Li, Y.-H., T.-H. Peng, and W.S. Broecker. A reply to the paper by Austin and Green, "The role of baroclinic eddies in mixing tritium into the oceanic gyres." Tellus, 37B:186-187 (1985).

No abstract.

Long, R.B. Out of the SWAMP to a more certain life on the ocean wave. Nature, 313(5999):17-23 (1985).

No abstract.

Lord, S.J., and J.M. Piotrowicz. Vertical velocity structures in an axisymmetric, nonhydrostatic tropical cyclone model. Extended Abstracts Volume, 16th Conference on Hurricanes and Tropical Meteorology, Houston, TX, May 14-17, 1985. American Meteorological Society, Boston, 138-139 (1985).

No abstract.

Lowell, R.P., and P.A. Rona. Hydrothermal models for the generation of massive sulfide ore deposits. Journal of Geophysical Research, 90(B10):8769-8783 (1985).

The discovery of massive sulfide ore deposits at certain sites at active seafloor spreading centers provides a basis for considering the energetics of processes that have concentrated similar large ore deposits that have been preserved in volcanic rocks on land. In this paper we construct transport models based on hydrothermal convection systems in the oceanic crust. We investigate models in which the circulation is driven by heat extracted from the permeable crustal rocks themselves, as well as by heat conducted through the roof of a replenished, vigorously-convecting crustal magma chamber. If the hydrothermal fluids carry 100 ppm dissolved iron as found in black smokers on the East Pacific Rise and exit at 350°C or greater, calculations show that the heat content of the oceanic crust is insufficient to account for ore deposits of 3 Mt or greater. Heat extraction through the roof of a magma chamber, in conjunction with the formation of a thin (~1 km) layer of plated gabbro, may account for ore bodies of the order of 3 Mt, provided the permeability of the oceanic crust in the magma-hydrothermal fluid contact zone is 10-15 m² or less. If the conducting boundary layer was only 1 m thick, locally, for 10 years, the permeability could be as high as 10^-13 m². The permeability in the discharge zone could, conceivably, be two orders of magnitude greater than the permeability at depth. More work is needed on the details of the effects of magma chamber replenishment and off-axis like injection and on the role of magmatic fluids. Very large ore deposits (i.e., ~100 Mt) are probably formed in multiple hydrothermal cycles.

Marks, F.D. Evolution of the structure of precipitation in Hurricane Allen (1980). Monthly Weather Review, 113(6):909-930 (1985).

Reflectivity data from the airborne radar systems on board the three NOAA aircraft were gathered during six consecutive days in Hurricane Allen of 1980. The data have been used to specify the horizontal and vertical precipitation distribution within 111 km radius of the hurricane center. The evolution of the structure and intensity of the precipitation in the storm is described from representative time composite radar maps for seven research flights made during the six-day period. The eyewall was characterized by a narrow ring (12-15 km wide) of intense reflectivity (42-47 dBZ) surrounding the center of the storm at a radius that varied in time from 12-40 km. The eyewall had steep radial gradients of reflectivity (4-5 dB km^-1) and tilted radially outward in height. The rain bands were characterized by areas of enhanced reflectivity embedded in a region of stratiform rainfall that contained a distinct bright band at the height of the 0°C isotherm. The most striking changes in structure during the six-day period were the rapid contraction in eyewall radius and the devleopment of a secondary ring of intense reflectivity 80-100 km from the storm center. These changes in eye radius appeared to be related to the vortex evolution, as discussed by Willoughby and others. Changes in storm intensity, coincident with the eyewall radius changes, seemed to have little effect on the total storm rainfall or latent heat release. The maximum storm rainfall occurred when the storm had a double eyewall structure. After the period of the double eyewall, the mean rain rate in the eyewall increased as the storm approached maximum intensity. However, coincident with the increase in eyewall rain rate, the eyewall area decreased, resulting in little change in the total storm rainfall. The sequence of time composites provided the first opportunity to describe, quantitatively, the precipitation distribution within 111 km of the center of a mature hurricane that was away from land influences. The rainfall analysis showed that the mean rain rates in the eyewall were a factor of 6 greater than those outside the eyewall (11.3 mm h^-1 versus 1.8 mm h^-1), but because the eyewall region encompassed such a small area, it only contributed 40% of the total rainfall within a radius of 1° latitude of the storm center. The precipitation distribution around the storm was asymmetric; more rainfall occurred ahead of the storm than behind. In general, the maximum precipitation in the eyewall region was within 15-20° of the storm track. The maximum rainfall in the rainband region was 40-50° to the right of that in the eyewall.

Marmolejo, E., J.F. Festa, and R.L. Molinari. Heat budget and climatic atlas of the equatorial Atlantic Ocean during FGGE (First GARP Global Experiment) (1979). NOAA Technical Memorandum, ERL AOML-61 (PB86-111622), 82 pp. (1985).

Observations of surface oceanographic and meteorological fields collected during the first GARP Global Experiment (FGGE) in the equatorial Atlantic Ocean have been combined and averaged by month onto a 2° x 2° grid. Monthly distributions of sea surface temperature, wind speed and direction, air temperature, specific humidity, and cloud cover have been generated for the period from December 1978 through November 1979. Net short-wave and long-wave radiation, and sensible and latent heat flux distributions have been generated from surface data using the bulk aerodynamic formulas. Standard errors of the mean values have been computed along with monthly contoured plots of each oceanographic and meteorological variable.

Maul, G.A. Introduction to Satellite Oceanography. Martinus Nijhoff Publishers, Dordrecht/Boston/Lancaster, 606 pp. (1985).

Satellite oceanography is defined in this book as the application of the technology of aerospace electromagnetic sensing to the study of the oceans. The book aims to present a broad-based introduction to the subject for physical, biological, and geological oceanographers and managers; and it is suitable for use as a textbook for graduate students (it is based on a course for second-year graduate students in physical, biological, and geological oceanography). The subject is treated mathematically. The individual chapters are as follows: (1) an introduction, which includes a definition of units, a brief history of remote sensing, measuring philosophies, orbits, remote sensing, vehicles, and an overview of the data obtained; (2) a review of radiation physics, including blackbody radiation, Maxwell's equations, interaction of electromagnetic waves with matter, polarization, interaction with a plane surface, interpretation of Fresnel reflectivity, radiometry, radiance across an interface, and radiative transfer equations; (3) IR remote sensing and instrumentation, IR properties of the atmosphere and water, IR radiation transfer equation, atmosphere effects on IR sensing, IR measurement of surface temperature and heat flux, and applications; (4) visible remote sensing and instrumentation, visible optical properties of water and air, visible radiative transfer equation, visible solar irradiance of the sea, visible reflectance from beneath the ocean's surface, reflection from the sea surface, remote sensing of ocean color, photography, and applications; and (5) microwave remote sensing and instrumentation, microwave properties of water and air, microwave radiation transfer equation, passive and active microwave radiometry, and applications. Each chapter is provided with study questions. An extensive list of references and a glossary are given.

Maul, G.A. Observations of Gulf of Mexico inflow and outflow. Proceedings, Fifth Gulf of Mexico Information Transfer Meeting, New Orleans, LA, November 27-29, 1984. OCS Study, MMS 85-0008, 428-429 (1985).

No abstract.

Maul, G.A., and N.J. Bravo. Correction to "Fitting of satellite and in-situ ocean surface temperatures: Results for POLYMODE during the winter of 1977-1978." Journal of Geophysical Research, 90(C5):9211-9213 (1985).

No abstract.

Maul, G.A., and A. Herman. Mean dynamic topography of the Gulf of Mexico with application to satellite altimetry. Marine Geodesy, 9(1):27-44 (1985).

A new calculation of the mean dynamic sea surface topography for the Gulf of Mexico is presented. All available hydrographic, STD, and XBT data from the national archive and other sources are combined to calculate the mean dynamic height of the basin at 25 km horizontal spatial resolution using 1000 db as the reference level. In all, over 26,000 stations were considered, approximately 15% of which were rejected for geographic, oceanographic, or instrumental reasons. Most of the observations, taken between 1969 and 1973, were equally spread over all seasons except winter, and were mostly in the eastern Gulf. Standard error of the mean surface is estimated at less than �2 dyn-cm (dynamic centimeters). The mean dynamic topography is dominated by the 150 dyn-cm high associated with the Gulf Loop Current in the eastern basin, and by a cyclone/anticyclone pair in the western basin. Standard deviation about the mean relative to 450 db accounts for 75% of the 1000-db variation, and shows that more than �20 dyn-cm are associated with the Loop Current and �10-14 dyn-cm with the western Gulf cyclone/anticyclone feature.

Maul, G.A., D.A. Mayer, and S.R. Baig. Comparisons between a continuous three-year current-meter observation at the sill of the Yucatan Strait, satellite measurements of Gulf Loop Current area, and regional sea level. Journal of Geophysical Research, 90(C5):9089-9096 (1985).

From October 1977 through November 1980 a current-meter mooring was maintained in the Yucatan Strait. The meter was moored halfway between Mexico and Cuba, 145 m above the sill or in 1895 m of water. Motions of low frequency (<14^-1 cycles/day) are oriented approximately parallel to the isobaths, 021°-030° true. Net drift for three years is to the south-southwest at an average velocity of 1.8 cm s^-1. Sustained southward flows at intervals of eight months, which persisted for several months each, have average velocities of 5 cm s^-1, with randomly spaced bursts as high as 15 cm s^-1. Energy in subtidal frequency bands has significant peaks near 38^-1 and 19^-1 cycles/day, with a broad band of energy between 300^-1 and 200^-1 cycles/day. The latter peak is consistent with the approximately eight-month interval between the southward flow events. Comparison with weekly areal coverage of the Gulf Loop Current from Geostationary Operational Environmental Satellite infrared observations shows little covariation, except that eight months is typical of some anticyclonic eddy generation. There is little coherence of sill depth velocities with Naples sea level at subtidal frequencies, but with Miami there is coherence at several frequencies, notably 38^-1 and 19^-1 cycles/day. In the higher frequencies, the principal tidal motions are diurnal and are oriented somewhat across the isobaths toward the northwest, 346°-349° true, with counterrotating O₁ and K₁ constituents. No semidiurnal, inertial, or fortnightly energy is observed above the background continuum.

Maul, G.A., F. Chew, M.H. Bushnell, and D.A. Mayer. Sea level variation as an indicator of Florida Current volume transport: Comparisons with direct measurements. Science, 227(4684):304-307 (1985).

Sea level measurements from tide gauges at Miami, Florida, and Cat Cay, Bahamas, and bottom pressure measurements from a water depth of 50 m off Jupiter, Florida, and a water depth of 10 m off Memory Rock, Bahamas, were correlated with 81 concurrent direct volume transport observations in the Straits of Florida. Daily-averaged sea level from either gauge on the Bahamian side of the Straits was poorly correlated with transport. Bottom pressure off Jupiter had a linear coefficient of determination of r² = 0.93, and Miami sea level, when adjusted for weather effects, had r² = 0.74; the standard errors of estimating transports were ±1.2 × 10⁶ cubic meters per second, respectively. A linear multivariate regression, which combined bottom pressure, weather, and the submarine cable observations between Jupiter and the Bahamas, had r² = 0.94 with a standard error of estimating transport of ±1.1 × 10⁶ cubic meters per second. These results suggest that a combination of easily obtained observations is sufficient to adequately monitor the daily volume transport fluctuations of the Florida Current.

Maul, G.A., F. Williams, M. Roffer, and F. Sousa. Remotely sensed oceanographic patterns and variability of bluefin tuna catch in the Gulf of Mexico. Oceanologica Acta, 7(4):469-479 (1985).

Data from the Japanese longline bluefin fishery in the Gulf of Mexico for 1979 and 1980 were combined with in-situ oceanographic data from four research cruises and several ship-of-opportunity XBT transects, and with infrared and visible satellite imagery from GOES, TIROS-n, and NIMBUS-7. Catch per unit effort, CPUE, for Atlantic bluefin tuna (Thunnus thynnus thynnus) in 1979 was approximately one-third that in 1980 and appears to be associated with the area fished. Using GOES infrared data, the boundary of the Gulf Loop Current was located and compared with the CPUE; the high 1980 catch was correlated with proximity to the surface thermal front of the current and appears to reflect a change in fishing strategy between years. Correlations with other environmental factors such as sea surface temperature, temperature differences, time (spectral estimates), and configuration of the Loop Current, were generally inconclusive. Polar-orbiting satellite data, with at most twice-per-day observations, provided very few useful current boundary locations whereas GOES, with its hourly imagery schedule for oceanographic features, allowed comparisons almost every day during the fishing season. Operational application of satellite data to fisheries oceanography in the tropics and subtropics requires the high imaging frequency of geostationary vehicles because of cloud abundance, separation, and advection rates.

McLeish, W., and D.B. Ross. Reply to comments by F. Jackson and C. Peng to "Imaging radar observations of directional properties of ocean waves" by W. McLeish and D. Ross. Journal of Geophysical Research, 90(C4):7371-7375 (1985).

No abstract.

McLeish, W., and D.B. Ross. Wave refraction in an ocean front. Journal of Geophysical Research, 90(C6):11,929-11,938 (1985).

Side-looking airborne radar near Cape Hatteras, North Carolina, recorded images of ocean waves, wind streaks, and intermediate water bodies within the Gulf Stream front. In the enclosed waters of Pamlico Sound, the radar images showed good accuracy in defining directions and distinguished waves from wind streaks at overlapping frequencies in the spectrum. In passing through the cyclonic shear in the Gulf Stream front, waves from both sides turned to their left and so specified their directions of propagation. Differences between spectra obtained across the front are in accord with current refraction theory. An inverse wave refraction calculation furnished current shear values from which horizontal profiles of water velocity were compiled. The total calculated velocity change of 1.5 m/s is similar to previous measurements. A secondary front near shore contained a velocity difference of 0.25 m/s. Velocity changes across the Gulf Stream front were correlated with temperature changes. The radar there showed bands of high reflectivity at the edges of intermediate water bodies, whose temperature differences implied very small velocity steps. Increased roughness at the intermediate water boundaries was attributed to current interaction with waves.

Molinari, R.L. Heat balances of the surface mixed layer in the equatorial Atlantic and Indian Oceans during FGGE. In Proceedings, First National Workshop on the Global Weather Experiment, National Academy Press, 779-789 (1985).

No abstract.

Molinari, R.L., J.F. Festa, and E. Marmolejo. Evolution of sea-surface temperature and surface meteorological fields in the tropical Atlantic Ocean during FGGE, 1979: Part I. Description of surface fields and computation of surface energy fluxes. Progress in Oceanography, 14(1-4):401-420 (1985).

Observations of surface oceanographic and meteorological fields collected during the First GARP Global Experiment (FGGE) in the equatorial Atlantic Ocean have been combined and averaged by month onto a 2° × 2° grid. Monthly distributions of sea-surface temperature, wind speed and direction, air temperature, specific humidity, and cloud cover have been generated for the period from December 1978 through November 1979. Net short wave and long wave radiation, and sensible and latent heat flux distributions have been generated from the surface data using the bulk aerodynamic formulas. In 1979, large-scale patterns of all the climatic and heat budget variables are very similar to distributions determined from long-term climatological averages. Positive anomalies of SST in the region of the equatorial cold water tongue represent some region of systematic differences between the 1979 and climatological distributions. The positive SST anomalies are, in general, coincident with negative anomalies in the net oceanic heat gain. Negative heat gain anomalies are primarily caused by positive wind speed anomalies, through increased latent and sensible heat fluxes.

Molinari, R.L., J.F. Festa, and E. Marmolejo. Evolution of sea-surface temperature in the tropical Atlantic Ocean during FGGE, 1979: Part II. Oceanographic fields and heat balance of the mixed layer. Journal of Marine Research, 43(1):67-81 (1985).

Surface meteorological and surface and subsurface oceanographic data collected during 1979 are used to describe sea-surface temperature, mixed layer depth, zonal current component, and net oceanic heat gain fields and to estimate the terms in a heat balance relation for the mixed layer. The terms are evaluated monthly on a 6° of latitude by 10° of longitude grid which covers the equatorial Atlantic from 9°S to 9°N. The first balance tested is between changes in mixed layer temperature and surface energy fluxes. These fluxes can account for more than 75% of the variance in the original time series of the quadrangles along 6°S. Variance reductions are less along 10° (order of 50%) and 6°N (less than 25%). The addition of zonal advection improves some of the predictions but not significantly. Low variance reductions along 6°N, west of 20°W, are attributed to the uncertainties in the estimates of observed temperature change and surface fluxes. The small variance reductions east of 20°W, at 6°N and along 0°, may be related to the neglect of coastal and equatorial upwelling and meridional advection. A simple model is proposed which assumes an annual cycle for the intensity of mixing across the base of the mixed layer, most intense during summer, least intense during winter. Variance reductions at 0°, 5°W increase from 20% to 60% with the inclusion of mixing. Meridional advection may also account for a portion of the observed variability in mixed layer temperature.

Molinari, R.L., W.D. Wilson, and K. Leaman. Volume and heat transports of the Florida Current: April 1982 through August 1983. Science, 227(4684):295-297 (1985).

Absolute velocity and temperature profiles are used to estimate the volume transport through the Straits of Florida and, in combination with historical midbasin data, to estimate the total meridional heat flux through a section at 27°N. The mean annual volume transport of the Florida Current from April 1982 through August 1983 is 30.5 (+1) × 10⁶ cubic meters per second. The net northward heat flux through the 27°N section is 1.2 (±0.1) × 10¹⁵ watts. The volume transport is characterized by high values in the late spring and early summer and low values in the late fall and early winter. There is a similar cycle in total heat flux.

Molinari, R.L., G.A. Maul, F. Chew, W.D. Wilson, M.H. Bushnell, D.A. Mayer, K. Leaman, F. Schott, T. Lee, R. Zantopp, J. Larsen, and T. Sanford. Subtropical Atlantic Climate Studies: Introduction. Science, 227(4684):292-294 (1985).

This report is an introduction to the accompanying collection of reports that present the results of a two-year period of intensive monitoring of the Florida Current. Both direct observing systems (ship-deployed current profilers and moored current meters) and indirect observing systems (coastal tide gauge stations, bottom pressure gauge arrays, a submarine cable, acoustic arrays, and radar installations) were used to measure temperature and volume transport.

Niedoroda, A.W., D.J.P. Swift, A.G. Figueiredo, and G.L. Freeland. Barrier island evolution, middle Atlantic shelf, U.S.A., Part II: Evidence from the shelf floor. Marine Geology, 63(1-4):363-396 (1985).

Where the Atlantic coastal gradient is low and the substrate is unconsolidated, shoreface processes lead to an equilibrium shoreface surface, characterized by a straightened plan view and a concave-up profile. Maintenance of this surface during the post-glacial sea-level rise may lead to barrier formation by mainland beach detachment, where the outer oceanic shoreface is maintained by wave and current processes. Downwelling storm currents sweep sand from the shoreface of the middle Atlantic bight, transport it downcoast and seaward and deposit it on the adjacent inner shelf. Some of this sand is returned by the action of asymmetrical wave orbital currents during fair weather. However, there is a net loss in most areas. The loss is not made good by river sand input, since on the Atlantic Coast all river sand is trapped by estuaries. As a result the shoreface in these areas is undergoing erosional retreat. Mean horizontal retreat rates are on the order of 1-3 m yr^-1 but most movement occurs in brief episodes with recurrence rates on the order of several events per century. Erosional shoreface retreat, coupled with aeolian overshoot, storm washover and the movement of sand through inlets into the lagoons, has lead to landward migration of the Atlantic barriers through the Holocene period of sea-level rise. The landward retreat of the barrier as a whole is as dependent on inlet formation as it is on erosional shoreface retreat. Repeated inlet breaching and the downdrift migration of inlets yields coalescing flood tidal deltas within the lagoon. The resulting surface forms a platform on which the subaerial barrier deposits can advance under the impetus of storm washover and aeolian action. The backbarrier deposits eventually re-emerge at the shoreface, where their upper beds are eroded and recycled. The barrier thus migrates over a pavement of its own flood tidal deltas and washover fans; sand is added to the system partly through the erosion of updrift headlands but mainly by means of scour in inlets, which reaches down to the underlying Pleistocene. The modern shelf sand sheet is the debris blanket resulting from the retreat process. The leading edge occurs as a thin veneer of rip-current fallout on the shoreface; this is periodically stripped off by winter storms to expose the underlying backbarrier strata. Further seaward, shelf sands eroded from the shoreface rest disconformably on backbarrier deposits; shoreface, beach and dune strata are always missing. Every grain of sand in this shelf sand sheet has occupied a position on the beach or upper shoreface within the recent past. However, the sheet as a whole has been reconstituted; its primary structures are those of the inner shelf floor. Backbarrier sand and mud deposits, characterized by channeling and landward-dipping reflectors, can be traced for over 100 km seaward across the middle Atlantic shelf, beneath the modern sand sheet. The backbarrier stratum together with the overlying shelf sand layer constitutes the record of barrier retreat across the Atlantic shelf surface during Holocene time. The sheet-like nature of this record indicates that, viewed at the appropriate time scale, barrier migration is a continuous process.

Oakley, S.A., I.W. Duedall, J.H. Parker, and J.R. Proni. Continuous measurements of the dispersion of sewage sludge. In Wastes in the Ocean: Nearshore Waste Disposal, I.W. Duedall, D.R. Kester, P.K. Park, and B.H. Ketchum (eds.), John Wiley and Sons, New York, Volume 6, 383-408 (1985).

Three controlled sewage-sludge dumping experiments involving moving and stationary dumping in the New York Bight apex were conducted in July 1976; the goal was to obtain results on short-term spatial and temporal variations in sludge components in the water column after dumping events and to determine the length of time needed for the water column to return to the predumping state. Water-column properties measured before and after sludge discharge were temperature, salinity, dissolved oxygen, nutrient, and adenosine triphosphate. After the moving dump, which is associated with a large amount of turbulent mixing from the wake of the barge, sludge components were rapidly mixed within the pycnocline. Except for ammonium concentrations, the water column returned to predump conditions within 3 h after dumping. Horizontal underway (continuous) mapping of the sludge plume at the surface and at 1-, 6-, and 8-m depths showed the presence of several areas of sludge-seawater mixtures that appeared as oscillations in the concentration field. After the stationary dump, concentrations of sludge components (both dissolved and particulate) in the water column were greatest at approximate 5 m deep. Biological decomposition of sludge, as inferred from adenosine triphosphate production in dialysis bag experiments, occurred rapidly within 48 h after a moving dumping event.

Ooyama, K.V. The polar representation of tensor cross-spectra of winds. Extended Abstracts Volume, 16th Conference on Hurricanes and Tropical Meteorology, Houston, TX, May 14-17, 1985. American Meteorological Society, 182-183 (1985).

No abstract.

Palmer, D.R., L.M. Lawson, D.A. Seem, and Y.-H. Daneshzadeh. Ray path identification and acoustic tomography in the Straits of Florida. Journal of Geophysical Research, 90(C3):4977-4989 (1985).

The Florida Current, which flows through the Straits of Florida, transports a significant fraction of the heat which must be transferred from low to high latitudes in order for the earth to remain in thermal balance. While ocean acoustic tomography is an attractive candidate for monitoring this heat transport, its use is dependent on being able to identify individual ray paths. All published investigations of tomography have been concerned with deep-ocean propagation where experience has shown that paths can be identified. Propagation in the Straits is quite different from deep-ocean propagation, however. The sound speed is such that a ray path which travels modest distances necessarily experiences bottom bounces. It is not clear, a priori, that paths can be identified in the Straits. We report the results of an investigation of this question. Using a fast, specialized ray-tracing program, we analyzed the fluctuations in ray path geometry resulting from small perturbations in the bathymetry. We found that the topographic features amplify these fluctuations to such a degree that identification of individual rays becomes impossible after only a few bottom bounces. Consequently, there is no adequate interpretive tool for relating an acoustic signal recorded more than a few tens of kilometers from a source to the heat transport, i.e., for carrying out the tomographic inversion. We propose a way of overcoming this identification problem based on the use of acoustic profilers.

Paul, C.A., and M.C. Pazos. Data for EPOCS/FGGE drifting buoys: February 1979 through October 1980. NOAA Data Report, ERL AOML-4 (PB85-196970), 163 pp. (1985).

Since February 1979, AOML has intermittently deployed satellite-tracked drifting buoys in the eastern tropical Pacific as part of the EPOCS and FGGE experiments. This data report will cover the first 31 of these deployments with data through October 1980. Table 1 details the deployment times and locations of these buoys. Most of these deployments were in the South Equatorial Current (SEC) and a few were deployed in the North Equatorial Countercurrent (NECC). A variety of environmental sensors have been used, including water temperature, atmospheric pressure, wind speed, drogue tension, and internal battery voltage. The data collection and buoy location were performed by Service ARGOS.

Pazos, M.C., and C.E. Acero. Drifting buoy data from the equatorial Pacific Ocean for the period November 1, 1981 through December 31, 1983. NOAA Data Report, ERL AOML-7 (PB86-140878), 251 pp. (1985).

Since February 1979, AOML has regularly deployed satellite-tracked drifting buoys in the eastern tropical Pacific as part of the EPOCS program. This data report contains data collected during the period of November 1, 1981 through December 31, 1983. Deployment times and locations of these buoys are given. The basic buoy consists of a cylindrical spar buoy with a conical flotation collar and a ballasted 2 m by 10 m windowshade drogue attached to the surface float by a 10 m or 30 m nylon tether. A variety of environmental sensors have been used, including water temperature, wind speed, drogue tension, and battery voltage.

Peng, T.-H. Application of box models for geochemical modeling of ocean. Journal of the National Bureau of Standards, 90:530 (1985).

No abstract.

Peng, T.-H. Atmospheric CO₂ variations based on tree ring ¹³C data. In The Carbon Cycle and Atmospheric CO₂: Natural Variations--Archean to Present, E.T. Sundquist and W.S. Broecker (eds.). Geophysical Monograph 32, AGU, 123-131 (1985).

The reconstruction of atmospheric CO₂ concentrations over the last 150 years, based on a deconvolution of the tree-ring-based ¹³C record, is reviewed. Assuming that Freyer's latest composite ¹³C record for the northern hemisphere represents global changes in the ¹³C/¹²C ratio of atmospheric CO₂ induced by changes in atmospheric CO₂ concentration due to deforestation, soil manipulation, and combustion of fossil fuels, the deconvolution, using the modified box-diffusion model, gives the following results: (1) the magnitude of the integrated CO₂ release from the terrestrial biosphere since 1800 is about 90% of that from fossil fuel; (2) over the two-decade period covered by the Mauna Loa atmospheric CO₂ record, the input from the forest-soil source is about 15% of that from fossil fuels; (3) the ¹³C/¹²C trend and the atmospheric CO₂ anomaly over the last two decades have been dominated by the input of fossil fueld CO₂; and (4) the pre-1850 atmospheric CO₂ content is estimated to be about 266 ppm. The integrated amount of CO₂ released from the terrestrial biosphere between A.D. 1800 and 1980 is estimated to be 12 × 10¹⁵ mol which is to be compared with the previous estimate of 22 × 10¹⁵ mol on the basis of Freyer and Belacy's (1983) ¹³C data. This indicates that tree-ring ¹³C-based estimates are volatile and further changes are likely.

Peng, T.-H., and W.S. Broecker. PANDORA: An eleven-box geochemical model of the world ocean. In Carbon Dioxide Transfer in the Atmosphere-Ocean-Terrestrial System, R.S. Keir and W.H. Berger (eds.). Scripps Institution of Oceanography, SIO Reference 85-31, 113-121 (1985).

No abstract.

Peng, T.-H., and W.S. Broecker. The utility of multiple tracer distributions in calibrating models for uptake of anthropogenic CO₂ by the ocean thermocline. Journal of Geophysical Research, 90(C4):7023-7035 (1985).

Two-dimensional thermocline ventilation models for the temperate North Atlantic with differing circulation patterns were calibrated to yield a tritium distribution similar to that observed during the GEOSECS survey. These models were then run for ³He, bomb-produced ¹⁴C, radiokrypton, and freons. They were also run for the uptake of fossil fuel CO₂. While the models differ significantly in their ability to match the observed ³He and ¹⁴C distributions, these differences are not large enough to clearly single out one model as superior. This insensitivity of tracer-to-tracer ratio to model design is reflected by the near identity of the fossil fuel CO₂ uptake by the various models. This result suggests that the uptake of CO₂ by the sea is limited more by the rates of physical mixing within the sea than by gas exchange across the sea surface. If so, then the hope that models employing outcropping isopycnals will enhance the CO₂ uptake by the sea and thereby lead to a narrowing in the gap that exists for anthropogenic CO₂ budgets is not well founded. The interim strategy of using reservoir models calibrated by tracer distributions appears to be sound.

Philander, G., D. Halpern, D.V. Hansen, R. Legeckis, L. Miller, C. Paul, R. Watts, R. Weisberg, and M. Wimbush. Long waves in the equatorial Pacific. EOS Transactions, American Geophysical Union, 66(14):154, 156 (1985).

No abstract.

Powell, M.D. Airborne Doppler radar observations of the hurricane boundary layer. Extended Abstracts Volume, 16th Conference on Hurricanes and Tropical Meteorology, Houston, TX, May 14-17, 1985. American Meteorological Society, 3-4 (1985).

No abstract.

Ratnaswamy, M., W.D. Wilson, and R.L. Molinari. Current velocity and hydrographic observations in the Straits of Florida: Subtropical Atlantic Climate Study (STACS), 1983-1984. NOAA Data Report, ERL AOML-5 (PB86-108602), 24 pp. (1985).

The primary objective of the Sub-Tropical Climate Study (STACS) is to define which oceanographic processes are important in meridional heat flux. As the Florida Current has been shown to play an important role in this flux, the initial emphasis of STACS was to develop the capability to monitor the variability of oceanic heat and mass transport in the Straits of Florida. As described, STACS consisted of several separate projects designed to verify the ability of different remote sensing techniques to measure continuously Florida Current velocity, transport and/or temperature.

Rona, P.A. Book review: "The Geology of the Atlantic Ocean," by K.O. Emery and E. Uchupi (1984), 1,050 pp., Springer-Verlag Publishing Company. American Association of Petroleum Geologists Bulletin, 69:2162-2163 (1985).

No abstract.

Rona, P.A. Hydrothermal mineralization at slow-spreading centers: Red Sea, Atlantic Ocean, and Indian Ocean. Marine Mining, 5(2):117-145 (1985).

Hydrothermal mineralization along slow-spreading oceanic ridges and rift zones that comprise more than half the global length of the seafloor spreading-center system is related to anomalous physical and chemical conditions acting within the geologic settings that characterize early and advanced stages of opening is represented by the Atlantic II Deep of the Red Sea. There, hypersaline hydrothermal solutions, discharging as density-stratified brines into an axial basin, have formed the largest massive sulfide deposit (32.5 x 10 metric tons of metal) known at a spreading center. Mineralization at the advanced stage of opening is represented by two types of sites: (1) oceanic crust on the wall of a rift valley; and (2) oceanic crust exposed on the wall of a transform fault zone. The first type of site is the TAG Hydrothermal Field, located on a wall of the rift valley of the Mid-Atlantic Ridge at the top of the basaltic layer of oceanic crust. Evidence is presented for multistage, high- and low-temperature hydrothermal activity that produces Cu, Fe, and Zn enrichments within the thin sediment column and stratiform interlayered deposits of Mn oxides, Fe oxides, hydroxides, and silicates on the seafloor. The second type of site occurs along walls of transform fault zones of the equatorial Mid-Atlantic Ridge and Carlsberg Ridge, which exhibit stockwork-type Cu-Fe sulfide mineralization within the basaltic layer of oceanic crust. The mineralization observed at these two types of sites is inferred to be the product of predominantly leaky hydrothermal systems in which primary hydrothermal solutions mix with normal seawater to precipitate stockwork deposits of Cu-Fe-Zn sulfides beneath the seafloor, and the depleted, low-temperature solutions discharge at the seafloor to precipitate stratiform Mn and Fe deposits. Review of the limited field evidence and thermal considerations indicates that sites at slow-spreading centers offer potential for the occurrence of many types of hydrothermal mineral deposits. However, the relative proportions, frequency of occurrence, and distribution of the various deposit types are expected to exhibit significant differences between slow-spreading centers and intermediate- to fast-spreading centers.

Rona, P.A. Potential mineral and energy resources at submerged plate boundaries. Marine Technology Society Journal, 19(4):18-25 (1985).

The theory of plate tectonics is briefly reviewed with reference to the recognized association between types of mineral (metals) and energy (hydrocarbons, geothermal) resources that may occur at sites along plate boundaries submerged beneath the oceans. An immense gap in knowledge, technology, and economics exists between the potential for mineral or energy resources to occur and the development of the resource as a commercial prospect. The real benefit of mineral discoveries such as polymetallic sulfides at submerged plate boundaries is to feed back information from the seabed to guide exploration for analogous deposits on land. A world map is presented showing the location of submerged plate boundaries and a 200 nautical mile-wide offshore zone.

Rona, P.A. The road to Jarmallio, critical years of the revolution in earth science. Bulletin of Marine Science, 36(2):400-401 (1985).

No abstract.

Rona, P.A., and R.A. Koski. Introduction to theme on marine polymetallic sulfides. Marine Mining, 5(2):101-102 (1985).

No abstract.

Shapiro, L.J. Objective analysis of winds in the three to five-day band over tropical Atlantic. Extended Abstracts Volume, 16th Conference on Hurricanes and Tropical Meteorology, Houston, TX, May 14-17, 1985. American Meteorological Society, Boston, 184-185 (1985).

No abstract.

SWAMP Group (D.B. Ross, L.M. Lawson, R.B. Long, and others). Ocean Wave Modeling. Plenum Press, New York, 256 pp. (1985).

This publication contains the results of the intercomparison study conducted by the Sea Wave Modeling Project (SWAMP) to test the current understanding of the physics of wind-generated surface waves from the viewpoint of wave modeling. The specific aim was to clarify the basic interdependences between understanding the physics of surface waves by representing the physics numerically and predicting quantitatively the detailed space-time evolution of a two-dimensional wave spectrum for a given wind field. The first part of this volume includes a discussion of the energy wave spectrum; model classes; test strategy; decoupled propagation models; coupled discrete models; tests involving fetch- and duration-limited growth; starting fetch; half-plane wind field; 90-degree change in wind direction; diagonal front; and stationary and moving hurricanes. Appendices give a list of participants and consistency requirements for propagation operators in discrete spectral models. Part 2 presents descriptions of the models by the individual investigators: an MRI wave model, the VENICE model for wind wave prediction, the Norwegian wave model NOWAMO, the KNMI operational wave prediction model GONO, the TOHOKU wave model, the U.K. Meteorological Office operational model, intercomparison test version of the SAIL wave model, the DNS model, an improved spectral model for ocean wave prediction, and the EXACT-NL wave model.

Swift, D.J.P., W. Stubblefield, T.L. Clarke, R.A. Young, G.L. Freeland, G.R. Harvey, and B. Hilliard. Sediment budget in the New York Bight dumpsites: Implications for pollutant dispersal. In Wastes in the Ocean: Nearshore Waste Disposal, I.W. Duedall, D.R. Kester, P.K. Park, and B.H. Ketchum (eds.). John Wiley and Sons, New York, Volume 6, 319-355 (1985).

The fine-sediment transport system of the New York Bight apex is highly dispersive, the residence time of particles subject to storm current and tidal current transport, excluding those involved in the high-speed productivity cycle, is 10.6 d. Transport in the New York Bight is tidally induced in estuaries, lagoons, and tidal inlets but storm-induced on the open shelf. Intense winter storms can resuspend 10⁴ t km^-2 of the fine sediment over several hours, and the particles follow mean trajectories of tens of kilometers for several days before settling out. Fine-sediment transport may be modeled as a diffusion-advection system, in which time and space scales are in the order of tens of kilometers and hundreds of years. Three important pathways of the sediment transport system are the southwesterly directed along-shelf flux, conservatively estimated at 10^-6 t y^-1; the Hudson River input of 10^-6 t y^-1; and the portion of dumped material that escapes burial and joins the transport system (3 x 10⁵ t y^-1). The productivity cycle (1.4 x 10⁷ t y^-1) from living organisms to organic matter and back overwhelms most other pathways. Marshes, estuaries, and lagoons in the bight apex are important sinks (estimated to receive 2.4 x 10⁶ t y^-1 of fine sediment). Coprostanol ratios reveal significant sewage-sludge contamination of lagoons and estuaries, although the point of entry of the sewage cannot be established. At least 10⁶ of fine sediment escapes south along the New Jersey coast each year. Other sinks for suspended fine sediment include the Christiaensen Basin, where ocean dumping occurs (2.3 x 10⁶ t y^-1), and the floor of the adjacent shelf valley. Depositional rates away from the dumpsite are lower (<10⁵ t y^-1), but the sediments reveal elevated coprostanol and trace metal values.

Tattelman, P., and P.T.Willis. Model vertical profiles of extreme rainfall rate, liquid water content, and drop-size distribution. Environmental Research Papers, Air Force Geophysics Laboratory, No. 928, AFGL Technical Report 85-0200, Hanscom AFB, MA, 34 pp. (1985).

This report provides a new model of hydrometeors and associated cloud-water content from the surface to 20 km. The model profiles at altitude were developed based on five surface rainfall rates: 36, 84, 168, 432, and 1872 mm/hr. The first three rates correspond to a frequency of occurrence of 0.5%, 0.1%, and 0.01% of the time during the worst month in the most severe area of the world for intense rainfall. The last two are the 42- and 1-min world record rainfalls. The surface rainfall rates were extrapolated aloft using results from previous studies. A large sample of drop-size distributions from intense rainfall collected during reconnaissance of Atlantic hurricanes/tropical storms was analyzed. The data set was normalized and fit by a gamma distribution. This was used to specify the drop-size distributions and liquid water content for rainfall rates specified at the surface and aloft. Concurrent cloud-water content was estimated. Results are presented at 2 km intervals.

Thompson, G., M.J. Mottl, and P.A. Rona. Morphology, mineralogy, and chemistry of hydrothermal deposits from the TAG area, 26°N Mid-Atlantic Ridge. Chemical Geology, 49(1-3):243-257 (1985).

Metalliferous hydrothermal deposits have been observed and sampled by submersible from the TAG Hydrothermal Field on the Mid-Atlantic Ridge at 26°N. The deposits include surficial metal-rich staining on the surface of carbonate ooze deposits over considerable areas of the sea floor as well as discrete massive layered deposits. The latter include hydrothermal precipitates of Fe-silicate (nontronite), Mn-oxide (birnessite) and Fe-oxide (amorphous). The deposits range in size from less than 1 m to ~15 m x 20 m. The composition and morphology of individual deposits varies from thick laminated crystalline birnessite precipitates, through Fe-rich tubular vents, to loose earthy birnessite, nontronite or amorphous Fe-oxide interlayered deposits. Fractionation and crystallinity are presumably controlled by local Eh conditions and the hydrodynamics of circulation in the upper crust. They are presumed to represent deposition from low-temperature hydrothermal solutions which had originally reacted with basaltic oceanic crust at depth at high temperature and had precipitated metal-rich sulfides within the crust. Occasional short-duration high-temperature black-smoker-type venting is inferred to have occurred based upon Cu-Fe-Zn-rich layers in the sediments and observations of clam shells in bottom photographs.

Trefry, J.H., R.P. Trocine, and J.R. Proni. Drilling-fluid discharges into the northwestern Gulf of Mexico. In Wastes in the Ocean: Nearshore Waste Disposal, I.W. Duedall, D.R. Kester, P.K. Park, and B.H. Ketchum (eds.). Wiley-Interscience, New York, Volume 4, 196-222 (1985).

This chapter investigates the dispersion and fate of drilling-fluid components discharged into the marine environmental with special focus on the Texas Flower Garden Banks (Flower Gardens) area of the northwestern Gulf of Mexico. Particulate Ba was found to be the best overall tracer of drilling-fluid dispersion; however, routine monitoring of raw effluent for dissolved and particulate Cr and Fe, total petroleum hydrocarbons, total solids, and one other representative particulate trace metal (As, Cd, Hg, or Pb) is also recommended. During field experiments, we observed: (1) differential settling of the barite and clay components; (2) that the barite component was less susceptible to resuspensoin than was normal sediment; (3) that natural particle-rich layers can be distinguished from drilling-related lenses; and (4) that the long-term, net directional movement of the released fluids can be established. Near the coral reefs of the Flower Gardens, drilling fluids are presently discharged to within 10 m of the bottom, a depth that is at least 100 m below the sea surface and at least 80 m below the top of the reefs. Resuspension processes, even during storms, do not carry bottom sediment, and thus the deposited matter from drilling fluid, onto the living reef. Although the drilling area to the north has higher than normal concentrations of Ba in the sediment and in the suspended matter of the water column, no drilling-fluid movement from that area to the Flower Gardens was observed. In fact, Observed Ba enrichment in some surficial sediment samples taken 3-10 km away from drilling areas may be due to a natural remobilization process. Drilling-fluid-related increases in sedimentation rate and input of different sediment types at the reef base remain as possible concerns.

Trefry, J.H., S.Metz, R.P. Trocine, and T.A. Nelsen. A decline in lead transport by the Mississippi River. Science, 230(4724):439-441 (1985).

Inputs of pollutant lead to the Gulf of Mexico from the Mississippi River have declined by about 40% within the past decade. This decrease has been determined from annual lead loads of the Mississippi River and from the lead record in Mississippi Delta sediments. The observed trend is consistent with reduced consumption of lead in gasoline in the United States. More than 90% of the riverborne lead is associated with suspended sediments. Most of the particle-bound lead is deposited within 50 km of the river mouth and is easily leached at pH values above 3.

Tsai, J.J., and J.R. Proni. Acoustic study of dredged-material dumping in the New York Bight. In Wastes in the Ocean: Nearshore Waste Disposal, I.W. Duedall, D.R. Kester, P.K. Park, and B.H. Ketchum (eds.). John Wiley and Sons, New York, Volume 6, 357-381 (1985).

In June 1979, an experiment on the disposal of dredged material in the New York Bight apex was performed in which acoustical, chemical, and hydrographic data were obtained. Prior to the disposal, the water column was clearly stratified, presenting both a potential dispersion floor and a dispersion ceiling. Immediately after the disposal operation, two surface sublayers with different salinities appeared on the temperature-salinity diagram, indicating a less saline surface layer at the dump site. The floor and ceiling effects were shown in the plume structure obtained by acoustic measurement. A two-process diffusion, calculated from the Joseph-Sendner model, was observed; each process exhibited a different diffusion velocity and spatial variation. The highest particle concentrations decayed by the second power of time. The variances were one order of magnitude larger than the average source diffusion, probably due to the larger settling velocity of dredged material during the measured period. The particle budget based on the acoustic calculations decreased exponentially as a function of time for each of the three water layers (surface, pycnocline, and bottom nepheloid) as well as for the water column as a whole. Direct relationships were found between observed acoustic intensity and calculated acoustic intensity and between measured total suspended matter and total suspended matter calculated by using numbers of particles and particle sizes.

Vukovich, F.M., and G.A. Maul. Cyclonic eddies in the eastern Gulf of Mexico. Journal of Physical Oceanography, 15(1):105-117 (1985).

Cold-domed cyclonic eddies juxtaposed to the cyclonic shear side of the Gulf Loop Current are observed in simultaneously obtained hydrographic, current meter mooring, and satellite infrared data. The cyclones are initially observed in the satellite data as cold perturbations on the northern extreme of the current and grow either into a cold tongue or a quasi-stable meander off the Dry Tortugas, Florida. Areal shipboard surveys show closed isopleths of temperature and salinity, and surface geostrophic current speeds relative to 1000 db are in excess of 100 cm s^-1. The diameter of the cold domes varied from 80 to 120 km. Separation of large anticyclonic rings is always observed to be preceded by cyclonic eddies in the transition zone between Campeche Bank and the West Florida Shelf, but only on the eastern side. Not every cyclonic eddy off Dry Tortugas is associated with the separation of an anticyclonic ring; some are eroded away by the Florida Current, but they have never been observed in 10 years of satellite data to advect eastward through the Straits of Florida.

Willis, P.T. Microphysics of a stratiform melting layer in Hurricane Alicia. Extended Abstracts Volume, 16th Conference on Hurricanes and Tropical Meteorology, Houston, TX, May 14-17, 1985. American Meteorological Society, Boston, 14-15 (1985).

No abstract.

Willis, P.T. Reply. Journal of the Atmospheric Sciences, 42(12):1349-1350 (1985).

No abstract.

Willoughby, H.E. Confirmatory observations of concentric eyes in hurricanes. Extended Abstracts Volume, 16th Conference on Hurricanes and Meteorology, Houston, TX, May 14-17, 1985. American Meteorological Society, Boston, 1-2 (1985).

No abstract.

Willoughby, H.E., D.P. Jorgensen, R.A. Black, and S.L. Rosenthal. Project STORMFURY: A scientific chronicle, 1962-1983. Bulletin of the American Meteorological Society, 66(5):505-514 (1985).

Between 1962 and 1983, research in hurricane modification centered on an ambitious experimental program, Project STORMFURY. The proposed modification technique involved artificial stimulation of convection outside the eyewall through seeding with silver iodide. The artificially invigorated convection, it was argued, would compete with the convection in the original eyewall, lead to reformation of the eyewall at larger radius, and thus produce a decrease in the maximum wind. Since a hurricane's destructive potential increases rapidly as its maximum wind becomes stronger, a reduction as small at 10% would have been worthwhile. Modification was attempted in four hurricanes on eight different days. On four of these days, the winds decreased by between 10 and 30%. The lack of response on the other days was interpreted to be the result of fault execution of the experiment or poorly selected subjects. These promising results have, however, come into question because recent observations of unmodified hurricanes indicate: (1) that cloud seeding has little prospect of success because hurricanes contain too much natural ice and too little supercooled water; and (2) that the positive results inferred from the seeding experiments in the 1960s probably stemmed from inability to discriminate between the expected effect of human intervention and the natural behavior of hurricanes.

Wilson, W.D., C. Roffer, and G.G. Thomas. Pegasus current profiler measurements collected for EPOCS, 1980-1983. NOAA Data Report, ERL AOML-6 (PB86-113446), 184 pp. (1985).

Current velocity profiles recorded on nine AOML EPOCS (Equatorial Pacific Ocean Climate Studies) cruises during 1980-1983 using the Pegasus profiler are presented. The data were collected along several equatorial transects from 85°W to 110°W. Station locations and current profiles are shown for each cruise; the instrument and techniques of data acquisition and processing are also described.

Young, R.A., and R. Mann. Erosion velocities of skeletal carbonate sands, St. Thomas Virgin Islands. Marine Geology, 69(1-2):171-185 (1985).

Erosional shear velocities, µ*, for irregular skeletal carbonate sands were determined from seagoing flume experiments on the insular shelf of St. Thomas to be in the range 0.4-1.0 cm s^-1. Erosional velocities are only weakly correlated with grain size and do not correlate well with various shape factors. Non-dimensional Shields and Yalin plots of the skeletal sand data overlap but fall mainly below the accepted curves for spherical grains, and corrections for grain shape only slightly improve the fit to the curves. This result is consistent with other experiments which show that threshold curves for regular (flaky) non-spherical grains form separate trends from the established curves for spherical grains. This suggests that only approximate agreement with accepted non-dimensional threshold curves may be expected for irregular grains until a better method is found to characterize and correct grain size and shape.

Young, R.A., D.J.P. Swift, T.L. Clarke, G.R. Harvey, and P.R. Betzer. Dispersal pathways for particle-associated pollutants. Science, 229(4712):431-435 (1985).

Particle-associated pollutants (totaling 10⁷ metric tons per year) are introduced into the New York Bight by ocean dumping, estuarine discharge, sewage outfalls, eolian transport, and shipping waste and spillage. Oceanic and estuarine circulation processes dilute and transport the particles by a natural dispersal system that also tends to be highly distributive; particle-associated pollutants apparently seek the same sinks in the Hudson River shelf valley and intracoastal wetlands, regardless of their point of introduction. **1984**

Benggio, B.L., and T.A. Nelsen. SLABBER: A useful device for subsampling box cores. Sedimentology, 31:879-882 (1984).

The SLABBER, a plexiglass device designed for subsampling box cores, was used at sea with excellent results. The SLABBER allowed visual inspection of any existing sedimentary features and also provided storage, when necessary, for subsamples. When the features were present, x-radiography of the SLABBER subsamples clearly showed sediment layering, evidence of bioturbation and orientation of shell material, all with apparent minimal disturbance of these structures.

Burpee, R.W., D.G. Marks, and R.T. Merrill. An assessment of Omega dropwindsonde data in track forecasts of Hurricane Debby (1982). Bulletin of the American Meteorological Society, 65(10):1050-1058 (1984).

Omega dropwindsondes (ODWs) were released from two NOAA WP-3D aircraft to measure the environmental wind field in the middle and lower troposphere within 1000 km of the center of Hurricane Debby on 15 and 16 September 1982. The observations were coded in standard formats and transmitted from the aircraft to the National Hurricane Center (NHC) and the National Meteorological Center (NMC) before operational forecast deadlines. The ODW winds clearly indicated the location and strength of a midtropospheric trough in the westerlies that was the major synoptic-scale feature affecting Debby's motion. On 16 September, the dropwindsondes also identified a smaller scale cutoff low in the northern part of the trough. The cutoff low that was centered about 500 km to the north northwest of Debby affected the hurricane's motion from midday on the 16th to midday on the 17th. The ODWs provided NHC with timely information that was used subjectively in determining the official forecasts of Debby's track. The potential of the ODWs to improve the track models that serve as guidance for the forecasters at NHC depends upon both the quality of the ODW data and the ability of the operational objective analyses to respond to the ODW data. In 1982, the objective analysis that initialized several of the track models was a spectral analysis with a global domain. At 500 mb, the scale of the wind circulations; of Debby and the cutoff low was approximately 500 km. The global operational objective analysis did not resolve these important features. The ODW data can help to improve the objective guidance for the hurricane forecasters only if the operational objective analyses and the track models are designed to make use of the ODW information. to obtain the data needed to revise current models and to develop new models, ODW experiments are planned in the next few years when hurricanes threaten the Atlantic or Gulf coasts of the United States.

Clarke, T.L., J.R. Proni, and J.F. Craynock. A simple model for the acoustic cross section of sand grains. Journal of the Acoustical Society of America, 76(5):1580-1582 (1984).

Previous work on determining the acoustic cross section of sand grains [(Geophys. Res. Lett., 9(2), 175-178 (1982)] identified a problem with the application of the simple compressible sphere model for the cross section. Use of the complete elastic sphere model [J. Acoust. Soc. Am., 34, 1582-1592 (1962)] failed to remove the conflict with observation. Application of the bistatic cross-section theorem to the angle averaged cross section shows that the appropriate cross section is the total absorption cross section, not the backscatter cross section. The total absorption cross section for the fluid sphere model is found to be in semiquantitative agreement with scattering data for sand grains.

Forde, E.B., S.D. Ulrich, and B. Hecker. Biological disturbance and camouflage of sedimentary features on the northeast United States slope and rise. Geo-Marine Letters, 4:49-53 (1984).

Evidence from over 200 sediment cores, numerous submersible dives, and bottom photographs prove that bioturbation and bioerosion are ongoing processes affecting northeastern U.S. continental slope and rise sedimentation. Evidence of biological activity was found in greater than 95% of the cores examined. Submersible dive observations reveal that the results of biological activity often dominate seafloor microtopography. Bioturbation can disturb sediments several centimeters deep in a matter of seconds and is in some areas the primary sediment transport mechanism. Many cores with sandy intervals were profoundly disturbed by bioturbation. Biologically camouflaged sand-rich intervals can easily be missed by visual observation.

Friedman, H.A., C.A. Arnhols, N.M. Dorst, C.J. Nelson, and W.J. Brown. Airborne research meteorological data collected by the National Hurricane Research Laboratory (Hurricane Research Division/AOML) during the 1982-1983 hurricane seasons: Inventory and availability. NOAA Data Report, ERL AOML-3, 168 pp. (1984).

The history, nature, use, and availability of in-situ research meteorological data that have been gathered by specially instrumented aircraft have been described in several publications. In 1982, the National Hurricane Research Laboratory (NHRL), now Hurricane Research Division (HRD)/Atlantic Oceanographic and Meteorological Laboratory (AOML), published NOAA Data Report ERL AOML-2 (Friedman et al.) to document the airborne research meteorological data collected in support of its hurricane field programs during the WP-3D era (1976-1981). The present publication continues this documentation with an inventory and description of the research data that were obtained during the 1982 and 1983 hurricane seasons, and which are available at HRD/AOML.

Hansen, D.V., and C.A. Paul. Genesis and effects of long waves in the equatorial Pacific. Journal of Geophysical Research, 89(C6):10,431-10,440 (1984).

Data from 20 satellite-tracked drifting buoys deployed in the eastern equatorial Pacific Ocean during the summer of 1979 were used to investigate the nature, effects, and energetics of currents associated with cusp-shaped long waves that have been observed in satellite IR imagery of the sea surface during all except El Ni�o years. It is shown that the long waves are associated with a vigorous pattern of mesoscale eddies lying primarily between the equator and 7°N. The spatial structure of the eddy kinetic energy closely resembles the eigenfunctions obtained from Philander's (1978) investigation of barotropic instability of that part of the South Equatorial Current lying north of the equator. Computation of the energy exchange between the eddies and the mean field suggests an e-folding time of about two weeks for the eddies, and a braking effect on the mean flow comparable to a change of surface wind stress of a few tenths of a dyne per square centimeter. The eddies also effect an equatorward transport of heat that amounts to about two thirds the poleward heat transport of the divergent Ekman transport in the near surface waters.

Lord, S.J., H.E. Willoughby, and J.M. Piotrowicz. Role of a parameterized ice-phase microphysics in an axisymmetric, nonhydrostatic tropical cyclone model. Journal of the Atmospheric Sciences, 41(19):2836-2848 (1984).

Results of an axisymmetric, nonhydrostatic hurricane model are analyzed with emphasis on the role of a parameterized ice-phase microphysics Inclusion of ice processes produces dramatic differences in the structure and evolution of the simulated hurricane vortex. Mesoscale convective features are wore plentiful with ice, and the simulated vortex grows more slowly. Time and space-averaged budgets of key model variables show that cooling due to melting ice particles can initiate and maintain model downdrafts on a horizontal scale of tens of kilometers. This scale depends critically on both the horizontal advection of the parameterized snow particles detrained from the tops of convective updrafts and the mean fall speed of the particles toward the melting level. In situ production of snow particles results from a wide variety of parameterized microphysical processes and is significant factor in maintaining upper-level snow concentration. These processes are strongly height-dependent.

Mayer, D.A., K.D. Leaman, and T.N. Lee. Tidal motions in the Florida Current. Journal of Physical Oceanography, 14(10):1551-1559 (1984).

A linear relationship exists between sea level and the north component of the depth-averaged tidal velocity in the Straits of Florida. This relationship is used as a one-dimensional model to predict barotropic tidal currents across the Straits near 27°N. Predictions are independent of the choice of a sea-level reference site between Key West and Patrick Air Force Base. The model, when compared with three sets of depth-averaged velocity obtained from current profilers, can account for at least 70% of the variance in the diurnal and semidiurnal tidal bands. The predicted diurnal tidal current is dominant and can account for more than 80% of the predicted tidal energy. Twice a year the one-dimensional model yields a maximum amplitude of 12 cm s^-1 � 3.5 cm s^-1 (rms). This corresponds to a tidal transport of 5.1 x 106 m³ s^-1 � 1.5 x 10⁶ m³ s^-1 (5.1 Sv).

Pazos, M.C., and C.A. Paul. Drifting buoy data from the equatorial Pacific Ocean for the period of August 31, 1980 through April 30, 1982. NOAA Technical Memorandum, ERL AOML-60 (PB85-120046), 116 pp. (1984).

As part of the EPOCS program, free-drifting buoys have been deployed in the equatorial Pacific since 1979 to study the variations of sea surface temperatures and currents in the areas. This data report covers the history and behavior of those buoys successfully reporting and deployed from August 21, 1980 through April 30, 1982. A total of 17 buoys are included in this report.

Peterson, D.H., and J.F. Festa. Numerical simulation of phytoplankton productivity in partially mixed estuaries. Estuarine, Coastal, and Shelf Science, 19(5):563-589 (1984).

A two-dimensional steady-state model of light-driven phytoplankton productivity and biomass in partially mixed estuaries has been developed. Effects of variations in river flow, suspended sediment concentration, phytoplankton sinking, self-shading, and growth rates on distributions of phytoplankton biomass and productivity are investigated. Numerical simulation experiments show that biomass and productivity are particularly sensitive to variations in suspended sediment concentrations typical of natural river sources and to variations in loss rates assumed to be realistic but poorly known for real systems. Changes in the loss rate term within the range of empirical error (such as from dark bottle incubation experiments) cause phytoplankton biomass to change by a factor of two. In estuaries with adequate light pentration in the water column, it could be an advantage for phytoplankton to sink. Species that sink increase their concentration and form a phytoplankton maximum in a way similar to the formation of the estuarine turbidity maximum. When attenuation is severe, however, sinking species have more difficultty in maintaining their population.

Stanley, D.J., T.A. Nelsen, and R. Stuckenrath. Recent sedimentation on the New Jersey slope and rise. Science, 226(4671):125-133 (1984).

Radiocarbon dating and sedimentological studies of closely spaced cores indicate movement during the Holocene of sediments on the New Jersey continental slope and upper rise between Wilmington and Lindenkohl canyons. The uneven time-stratigraphic thickness of the late Quaternary sediment sections between cores and the nonuniform deposition rate at any given core site and among core sites show that the sediment blanket in canyon and intercanyon areas has been affected by downslope, gravity-driven processes during the Holocene to the present. The reduced rate of deposition on the slope and upper rise between the late Pleistocene and the present is largely due to decreased off-shelf transport in response to the eustatic rise in sea level. Very old radiocarbon dates at core tops result from emplacement of older reworked materials from upslope or from truncation of sections by mass wasting processes exposing older material at the sea floor. These processes also account for an irregular sequence of dated sections within cores and stratigraphic irregularities of the surficial cover from core to core. Marked variability in deposition rates on the slope and upper rise is largely a function of topographic configuration, proximity and accessibility to sediment source, and transport processes seaward of the shelf break. Moreover, higher accumulation rates on the upper rise are attributed primarily to slope bypassing. Bypassing, prevalent during the late Pleistocene, has continued periodically to the present.

Tsai, J.J. Acoustic remote sensing of waste disposal in the ocean. NOAA Technical Memorandum, ERL AOML-59 (PB85-110070), 108 pp. (1984).

Four ocean dumping experiments at three different locations of both shallow and deep water (30 to 3000 m) are discussed and used to illustrate the application of acoustic remote sensing in the study of waste disposal in the ocean. The dumped materials include pharmaceutical wastes, dredged matter, and filling fluid. Relative isoconcentration maps based on acoustic backscattered intensity measurements reveal plume structure and space-time particulate distribution of the dumped materials, as well as the physical oceanographic features of the water column. The analysis can be applied to other types of waste materials, and provide a new approach to monitor waste disposal in lakes, coastal zones, and open oceans.

Willoughby, H.E., F.D. Marks, and R.J. Feinberg. Stationary and moving convective bands in hurricanes. Journal of the Atmospheric Sciences, 41(22):3189-3211 (1984).

Aircraft observations in hurricanes indicate that the hurricane vortex may be subdivided into an inner gyre where the air trajectories form closed paths and an outer envelope where they do not. In the closed gyre, a core of air moves with the vortex; in the envelope, environmental air passes through the vortex and around the core. A system of spiral bands, termed the stationary band complex (SBC), forms near the boundary between the core and the envelope where the Rossby number is of order unity. The SBC differs dynamically both from convective rings because it is asymmetric and from propagating gravity-wave bands because its Doppler-shifted frequency is below the local inertia frequency. In more intense systems with stronger convective instability, the SBC may evolve into a convective ring and move into the vortex core. Outward propagating gravity-wave bands have also been observed. Such bands are often associated with track oscillations as the storm makes landfall or recurves. Spiral-shaped entities within the SBC tend to lie across the streamlines when the convective instability is small and along them when it is large. Storms moving through an environmental flow with westerly vertical shear exhibit an east-to-west drift across the vortex. This phenomenon is expressed in the asymmetric streamfunction as an anticyclonic eddy northeast of the center and a cyclonic eddy south of the center. The velocity potential has a divergent cell west of the center and convergent cell that extends along the inside of the SBC east of the center. This pattern is apparently forced by potential vorticity conservation along the trajectories of the rotational flow and by heating in the SBC. The irrotational flow between the two cells substantially cancels the rotational drift within the vortex core.