Category: Scientific Papers (Abstract & PDF)

The Extratropical Transition of Tropical Cyclones. Part I: Cyclone Evolution and Direct Impacts

Evans, C., K.M. Wood, S.D. Aberson, H.M. Archambault, S.M. Milrad, L.F. Bosart, K.L. Corbosiero, C.A. Davis, J.R. Dias Pinto, J. Doyle, C. Fogarty, T.J. Galarneau, C.M. Grams, K.S. Griffin, J. Gyakum, R.E. Hart, N. Kitabatake, H.S. Lentink, R. McTaggart-Cowan, W. Perrie, J.F. Quinting, C.A. Reynolds, M. Riemer, E.A. Ritchie, Y. Sun, and F. Zhang, 2017: The Extratropical Transition of Tropical Cyclones. Part I: Cyclone Evolution and Direct Impacts. Mon. Wea. Rev., 145, 4317–4344,

Abstract: Extratropical transition (ET) is the process by which a tropical cyclone, upon encountering a baroclinic environment and reduced sea surface temperature at higher latitudes, transforms into an extratropical cyclone. This process is influenced by, and influences, phenomena from the tropics to the midlatitudes and from the meso- to the planetary scales to extents that vary between individual events. Motivated in part by recent high-impact and/or extensively observed events such as North Atlantic Hurricane Sandy in 2012 and western North Pacific Typhoon Sinlaku in 2008, this review details advances in understanding and predicting ET since the publication of an earlier review in 2003. Methods for diagnosing ET…

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The Oceanic Sink for Anthropogenic CO2 from 1994 to 2007

Gruber, N., Clement, D., Carter, B. R., Feely, R. A., van Heuven, S., Hoppema, M., … & Monaco, C. L. (2019). The oceanic sink for anthropogenic CO2 from 1994 to 2007. Science, 363(6432), 1193-1199.


We quantify the oceanic sink for anthropogenic carbon dioxide (CO2) over the period 1994 to 2007 by using observations from the global repeat hydrography program and contrasting them to observations from the 1990s. Using a linear regression–based method, we find a global increase in the anthropogenic CO2 inventory of 34 ± 4 petagrams of carbon (Pg C) between 1994 and 2007. This is equivalent to an average uptake rate of 2.6 ± 0.3 Pg C year−1 and represents 31 ± 4% of the global anthropogenic CO2 emissions over this period. Although this global ocean sink estimate is consistent with the expectation of the ocean uptake having increased in proportion to the rise in atmospheric CO2, substantial regional differences in storage rate are found, likely owing to climate variability–driven changes in ocean circulation.

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Future Observing System Simulation Experiments

Hoffman, R. N., & Atlas, R. (2016). Future observing system simulation experiments. Bulletin of the American Meteorological Society, 97(9), 1601-1616.

Abstract: An additional set of challenges will arise when future DA systems strongly couple the different Earth system components. As operational forecast and data assimilation (DA) systems evolve, observing system simulation experiment (OSSE) systems must evolve in parallel. Expected development of operational systems—especially the use of data that are currently not used or are just beginning to be used, such as all-sky and surface-affected microwave radiances—will greatly challenge our ability to construct realistic OSSE systems.In response, future OSSE systems will require coupled models to simulate nature and coupled observation simulators. The requirements for future evolving OSSE systems and potential solutions to satisfy these requirements are discussed. It is anticipated that in the future the OSSE technique will be applied to…

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An Observing System Simulation Experiment with a Constellation of Radio Occultation Satellites

Cucurull, L., Atlas, R., Li, R., Mueller, M. J., & Hoffman, R. N. (2018). An Observing System Simulation Experiment with a Constellation of Radio Occultation Satellites. Monthly Weather Review, 146(12), 4247-4259.

Abstract: Experiments with a global observing system simulation experiment (OSSE) system based on the recent 7-km-resolution NASA nature run (G5NR) were conducted to determine the potential value of proposed Global Navigation Satellite System (GNSS) radio occultation (RO) constellations in current operational numerical weather prediction systems. The RO observations were simulated with the geographic sampling expected from the original planned Constellation Observing System for Meteorology, Ionosphere, and Climate-2 (COSMIC-2) system, with six equatorial (total of ;6000 soundings per day) and six polar (total of 6000 soundings per day) receiver satellites. The experiments also accounted for the expected improved vertical coverage provided by the Jet Propulsion Laboratory RO receivers on board COSMIC-2. Except that RO observations were simulated and assimilated as refractivities, the 2015 version of the NCEP’s operational data assimilation system was used to run the OSSEs. The OSSEs quantified the impact of RO observations on global weather analyses and forecasts and…
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Mechanisms of Eddy-Driven Variability of the Florida Current

Domingues, R. M., Johns, W. E., & Meinen, C. S. (2019). Mechanisms of Eddy-Driven Variability of the Florida Current. Journal of Physical Oceanography, 49(5), 1319-1338.

Abstract: In this study, mechanisms causing year-to-year changes in the Florida Current seasonality are investigated using controlled realistic numerical experiments designed to isolate the western boundary responses to westward propagating open ocean signals. The experiments reveal two distinct processes by which westward propagating signals can modulate the phase of the Florida Current variability, which we refer to as the “direct” and “indirect” response mechanisms. The direct response mechanism involves a two-stage response to open ocean anticyclonic eddies characterized by the direct influence of Rossby-wave barotropic anomalies, and baroclinic wall-jets that propagate through Northwest Providence Channel…

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Advances in Tropical Cyclone Intensity Forecasts

Atlas, R., Tallapragada, V., & Gopalakrishnan, S. (2015). Advances in tropical cyclone intensity forecasts. Marine Technology Society Journal, 49(6), 149-160.

Abstract: NOAA established the 10-year Hurricane Forecast Improvement Project (HFIP) to accelerate the improvement of forecasts and warnings of tropical cyclones and to enhance mitigation and preparedness by increased confidence in those forecasts. Specific goals include reducing track and intensity errors by 20% in 5 years and 50% in 10 years and extending the useful range of hurricane forecasts to 7 days. Under HFIP, there have been significant improvements to NOAA’s operational hurricane prediction model resulting in increased accuracy in the numerical guidance for tropical cyclone intensity predictions. This paper documents many of the improvements that have been accomplished over the last 5 years, as well as some future research directions that are being pursued. Keywords: hurricane, Hurricane Forecast Improvement Program (HFIP), Hurricane Weather Research and Forecasting Model (HWRF)

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