Category: Scientific Papers (Abstract & PDF)

Eye of the Storm: Observing Hurricanes with a Small Unmanned Aircraft System

Cione, J. J., Bryan, G. H., Dobosy, R., Zhang, J. A., de Boer, G., Aksoy, A., … & Chen, X. (2020). Eye of the storm: observing hurricanes with a small unmanned aircraft system. Bulletin of the American Meteorological Society, 101(2), E186-E205.

Abstract: Unique data from seven flights of the Coyote small unmanned aircraft system (sUAS) were collected in Hurricanes Maria (2017) and Michael (2018). Using NOAA’s P-3 reconnaissance aircraft as a deployment vehicle, the sUAS collected high-frequency (>1 Hz) measurements in the turbulent boundary layer of hurricane eyewalls, including measurements of wind speed, wind direction, pressure, temperature, moisture, and sea surface temperature, which are valuable for advancing knowledge of hurricane structure and the process of hurricane intensification. This study presents an overview of the sUAS system and preliminary analyses that were enabled by these unique data. Among the most notable results are measurements of turbulence kinetic energy and momentum flux for the first time at low levels (

Read Full Paper.

Read Full Article
First page of 'Inferring Florida Current Volume Transport From Satellite Altimetry' publication

Inferring Florida Current Volume Transport From Satellite Altimetry

Volkov, D. L., Domingues, R., Meinen, C. S., Garcia, R., Baringer, M., Goni, G., & Smith, R. H. (2020). Inferring Florida Current volume transport from satellite altimetry. Journal of Geophysical Research: Oceans, e2020JC016763.

Plain Language Summary: Florida Current (FC) is one of the major conduits of heat, salt, carbon, nutrients and other properties in the subtropical North Atlantic, with profound influences on regional weather, climate, sea‐level, and ecosystems. Daily monitoring of the FC volume transport with a submarine cable has been maintained nearly continuously since 1982. Because of the extremely high value of these measurements for Earth system studies, efforts are underway to find a suitable backup observing system for the inevitable future when the cable fails. Satellites have been providing accurate measurements of sea level for nearly 3 decades. Due to the Earth’s rotation, the direction of major oceanic currents is parallel to the lines of constant sea level, which for the FC translates into sea level near the Bahamas being about 1‐m higher than sea level along Florida east coast. Variations in the FC…

Read Full Paper.

Read Full Article
First page of 'Interannual Variability of the South Atlantic Ocean Heat Content in a High-Resolution Versus a Low-Resolution General Circulation Model' publication

Interannual Variability of the South Atlantic Ocean Heat Content in a High‐Resolution Versus a Low‐Resolution General Circulation Model

Gronholz, A., Dong, S., Lopez, H., Lee, S. K., Goni, G., & Baringer, M. (2020). Interannual variability of the South Atlantic Ocean heat content in a high‐resolution versus a low‐resolution General Circulation Model. Geophysical Research Letters, e2020GL089908.

Plain Language Summary: In this study we analyze heat content changes of the upper South Atlantic Ocean and the impact of model resolution on these changes. Results from two numerical simulations are compared. One simulation with high‐resolution allows smaller‐scale processes directly, while the other simulation with low‐resolution does not. In both simulations oceanic heat transport dominates the ocean heat content changes on interannual time scale, while atmospheric fluxes play a secondary role. The heat anomalies, however, originate from different regions in the two simulations. While the oceanic heat transport from the south dominates in the high‐resolution simulation, oceanic heat transport from the north dominates in the low‐resolution simulation. Furthermore, wind‐induced surface heat transport plays a significant role in the low‐resolution while the heat transport in the high‐resolution simulation is dominated by…

Read Full Paper.

Read Full Article
ENOCHS, I.C., N. FORMEL, L. SHEA, L. CHOMIAK, A. Piggot, A. KIRKLAND, and D. MANZELLO. Subsurface automated samplers (SAS) for ocean acidification research. Bulletin of Marine Science, 96(4):735-752 (https://doi.org/10.5343/bms.2020.0018) (2020).

Subsurface Automated Samplers (SAS) for Ocean Acidification Research

ENOCHS, I.C., N. FORMEL, L. SHEA, L. CHOMIAK, A. Piggot, A. KIRKLAND, and D. MANZELLO. Subsurface automated samplers (SAS) for ocean acidification research. Bulletin of Marine Science, 96(4):735-752 (https://doi.org/10.5343/bms.2020.0018) (2020).

Abstract: Ocean acidification (OA) is the process whereby anthropogenic carbon dioxide is absorbed into seawater, resulting in altered carbonate chemistry and a decline in pH. OA will negatively impact numerous marine organisms, altering the structure and function of entire ecosystems. The progression of OA, while faster than has occurred in recent geological history, has been subtle and detection may be complicated by high variability in shallow-water environments. Nevertheless, comprehensive monitoring and characterization is important given the scale and severity of the problem. Presently, technologies used to measure OA in the field are costly and limited by their detection of only one carbonate chemistry parameter, such as pH. Discrete water samples, by contrast, offer a means of measuring multiple components of the carbonate system, including parameters of particular explanatory value (e.g., total alkalinity, dissolved inorganic carbon), for which field-based sensors do not presently exist…

Read Full Article

Read Full Article
First page of 'Madden-Julian Oscillation-Induced Suppression of Northeast Pacific Convection Increase U.S. Tornadogenesis' publication

Madden–Julian Oscillation–Induced Suppression of Northeast Pacific Convection Increases U.S. Tornadogenesis

Kim, D., Lee, S. K., & Lopez, H. (2020). Madden–Julian Oscillation–Induced Suppression of Northeast Pacific Convection Increases US Tornadogenesis. Journal of Climate, 33(11), 4927-4939.

This study investigates the impact of the Madden–Julian oscillation (MJO) on U.S. tornadogenesis using atmospheric reanalysis and model experiments. Our analysis shows that the impact of MJO on U.S. tornadogenesis is most significant in May–July and during MJO phases 3–4 and 5–6 (P3456). These MJO phases are characterized by anomalous ascending motion over the Maritime Continent (MC) and anomalous subsidence over the northeast Pacific (EP), generating anomalous diabatic heating and cooling, respectively. These in turn generate large-scale atmospheric conditions conducive to tornadogenesis in the United States, enhancing the North American low-level jet (NALLJ) and thus increasing the influx of warm and moist air from the Gulf of Mexico to the United States and increasing the low-level wind shear and convective available potential energy along its path…

Read Full Paper

Read Full Article
First page of 'Observed Ocean Bottom Temperature Variability at Four Sites in the Northwestern Argentine Basin: Evidence of Decadal Deep/Abyssal Warming Admidst Hourly to Interannual Variability During 2009-2019' publication

Observed Ocean Bottom Temperature Variability at Four Sites in the Northwestern Argentine Basin: Evidence of Decadal Deep/Abyssal Warming Amidst Hourly to Interannual Variability During 2009–2019

Meinen, C. S., Perez, R. C., Dong, S., Piola, A. R., & Campos, E. (2020). Observed ocean bottom temperature variability at four sites in the northwestern Argentine Basin: Evidence of decadal deep/abyssal warming amidst hourly to interannual variability during 2009‐2019. Geophysical Research Letters, e2020GL089093.

Consecutive multiyear records of hourly ocean bottom temperature measurements are merged to produce new decade‐long time series at four depths ranging from 1,360 to 4,757 m within the northwest Argentine Basin at 34.5°S. Energetic temperature variations are found at a wide range of time scales. All sites exhibit fairly linear warming trends of approximately 0.02–0.04°C per decade over the period 2009–2019, although the trends are only statistically different from zero at the two deepest sites at depths of ~4,500–4,800 m. Near‐bottom temperatures from independent conductivity‐temperature‐depth profiles collected at these same locations every 6–24 months over the same decade…

Read full paper

Read Full Article

Natural and Anthropogenic Drivers of Acidification in Large Estuaries

Natural and Anthropogenic Drivers of Acidification in Large Estuaries Wei-Jun Cai, Richard A. Feely, Jeremy M. Testa, Ming Li, Wiley Evans, Simone R. Alin, Yuan-Yuan Xu, Greg Pelletier, Anise Ahmed, Dana J. Greeley, Jan A. Newton, Nina Bednaršek Annual Review of Marine Science 2021 13:1

Oceanic uptake of anthropogenic carbon dioxide (CO2) from the atmosphere has changed ocean biogeochemistry and threatened the health of organisms through a process known as ocean acidification (OA). Such large-scale changes affect ecosystem functions and can have effects on societal uses, fisheries resources, and economies. In many large estuaries, anthropogenic CO2-induced acidification is enhanced by strong stratification, long water residence times, eutrophication, and a weak acid–base buffer capacity. In this article, we review how a variety of processes influence aquatic acid–base properties in estuarine waters, including river–ocean mixing, upwelling, air–water gas exchange, biological production and subsequent respiration, anaerobic respiration, calcium carbonate (CaCO3) dissolution, and benthic inputs…

Read Full Paper

Read Full Article

Vertical Turbulent Cooling of the Mixed Layer in the Atlantic ITCZ and Trade Wind Regions

Foltz, G. R., Hummels, R., Dengler, M., Perez, R. C., & de Araujo, M. (2020). Vertical turbulent cooling of the mixed layer in the Atlantic ITCZ and trade wind regions. Journal of Geophysical Research: Oceans, 125, e2019JC015529. https://doi.org/10.1029/2019JC015529

Abstract:
The causes of the seasonal cycle of vertical turbulent cooling at the base of the mixed layer are assessed using observations from moored buoys in the tropical Atlantic Intertropical Convergence Zone (ITCZ) (4N, 23W) and trade wind (15N, 38W) regions together with mixing parameterizations and a one-dimensional model. At 4N the parameterized turbulent cooling rates during 2017–2018 and 2019 agree with indirect estimates from the climatological mooring heat budget residual: both show mean cooling of 25–30W/m^2 during November–July, when winds are weakest and the mixed layer is thinnest, and 0–10W/m^2 during August–October. Mixing during November–July is driven by variability on multiple time scales, including subdiurnal, near-inertial, and intraseasonal…

Read Full Paper

Read Full Article

Advances in the Application of Surface Drifters

Lumpkin, R., Özgökmen, T., & Centurioni, L. (2017). Advances in the application of surface drifters. Annual Review of Marine Science, 9, 59-81.

Abstract:

Surface drifting buoys, or drifters, are used in oceanographic and climate research, oil spill tracking, weather forecasting, search and rescue operations, calibration and validation of velocities from high-frequency radar and from altimeters, iceberg tracking, and support of offshore drilling operations. In this review, we present a brief history of drifters, from the message in a bottle to the latest satellite-tracked, multisensor drifters. We discuss the different types of drifters currently used for research and operations as well as drifter designs in development. We conclude with a discussion of the various properties that can be observed with drifters, with heavy emphasis on a critical process that cannot adequately be observed by any other instrument: dispersion in the upper ocean, driven by turbulence at scales from waves through the submesoscale to the large-scale geostrophic eddies.

Download Full PDF

Read Full Article

Precipitation Processes and Vortex Alignment during the Intensification of a Weak Tropical Cyclone in Moderate Vertical Shear

Rogers, R. F., Reasor, P. D., Zawislak, J. A., & Nguyen, L. T. (2020). Precipitation Processes and Vortex Alignment during the Intensification of a Weak Tropical Cyclone in Moderate Vertical Shear. Monthly Weather Review, (2020).

Abstract:

The mechanisms underlying the development of a deep, aligned vortex, and the role of convection and vertical shear in this process, are explored by examining airborne Doppler radar and deep-layer dropsonde observations of the intensification of Hurricane Hermine (2016), a long-lived tropical depression that intensified to hurricane strength in the presence of moderate vertical wind shear. During Hermine’s intensification the low-level circulation appeared to shift toward locations of deep convection that occurred primarily downshear. Hermine began to steadily intensify once a compact low-level vortex developed within a region of deep convection in close proximity to a midlevel circulation, causing vorticity to amplify in the lower troposphere primarily through stretching and tilting from the deep convection…

Download PDF

Read Full Article