Author: AOML Communications

Observed relationships between tropical cyclone vortex height, intensity, and intensification rate. Image of the scientific paper

Observed Relationships Between Tropical Cyclone Vortex Height, Intensity, and Intensification Rate

DesRosiers, A. J., Bell, M. M., Klotzbach, P. J., Fischer, M. S., & Reasor, P. D. (2023). Observed relationships between tropical cyclone vortex height, intensity, and intensification rate. Geophysical Research Letters, 50(8), e2022GL101877.

Abstract: As a tropical cyclone (TC) intensifies, the tangential wind field expands vertically and increases in magnitude. Observations and modeling support vortex height as an important TC structural characteristic. The Tropical Cyclone Radar Archive of Doppler Analyses with Recentering data set provides kinematic analyses for calculation of the height of the vortex (HOV) in observed storms. Analyses are azimuthally-averaged with tangential wind values taken along the radius of maximum winds. A threshold-based technique is used to determine the HOV. A fixed threshold HOV strongly correlates with current intensity. A dynamic HOV metric quantifies vertical decay of tangential wind with reduced dependency on intensity. Statistically significant differences are present between dynamic HOV values in groups of steady-state, intensifying, and rapidly-intensifying cases categorized by subsequent changes in pressure.

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NOAA Corps officers on the bridge of NOAA vessel, Nancy Foster, navigating out at sea.

May 22nd is the NOAA Commissioned Officer Corps (NOAA Corps) 106th Birthday!

The NOAA Commissioned Officer Corps is one of the nation’s eight uniformed services and its officers are an integral part of the National Oceanic and Atmospheric Administration (NOAA). With approximately 330 officers and growing, the NOAA Corps supports nearly all of NOAA’s programs and missions. The combination of commissioned service and scientific expertise makes these officers uniquely capable of leading some of NOAA’s most important initiatives.

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A very large amount of orange/brown seaweed (sargassum) washed up on the coastline.

Extreme climate event in North Atlantic may have kicked off Sargassum explosion a decade ago

When massive mounds of golden-brown seaweed began piling up on beaches throughout the Caribbean and West Africa in summer of 2011, the question of where it came from probably mattered less to residents and businesses than how they were going to get rid of it. Certainly, few would have connected the Sargassum seaweed invasion to the extremely snowy 2010-11 winter in the eastern United States. But according to a hypothesis proposed by a team of NOAA AOML-led scientists in 2020, the two phenomena share an origin story: an extremely strong and long-lasting shift of the North Atlantic Oscillation into its negative phase back in 2010.

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Photo of Sargassum Floating in Open Water. Photo Credit: Credit: NOAA Teacher at Sea Program, NOAA Ship OREGON II Blue economy

Massive bloom of seaweed in tropical Atlantic raises the risk for Caribbean, Gulf, and Florida beach impacts in coming months

Earlier this year, ocean scientists raised an alert about the large amount of seaweed drifting in the tropical Atlantic this spring. Experts warned that the region’s annual spring bloom of Sargassum—a free-floating brown macroalgae from the North Atlantic that suddenly appeared in large quantities in the tropics in 2011— was the densest observed in March since scientists began tracking the phenomenon with satellite images twenty years ago. Excessive amounts of Sargassum raise the chances that large mats will break free from the prevailing currents and wash ashore later this spring and summer in the Caribbean, Gulf of America, and around Florida.

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Eddies in the Caribbean Sea Influence the Prediction of the Loop Current in the Gulf of America  

A recent study by scientists at NOAA’s Atlantic Oceanographic and Meteorological Laboratory (AOML) in collaboration with partners at the University of Miami’s Rosenstiel School of Marine, Atmospheric, and Earth Science used a numerical modeling approach to investigate the impact of the eddy field in the Caribbean Sea on Loop Current predictions downstream in the Gulf of America. They found that eddy activity in the Caribbean Sea is crucial for the accurate prediction of eddy shedding by the Loop Current.

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High-Definition Hurricanes: Improving Forecasts with Storm-Following Nests: Image of the scientific paper

High-Definition Hurricanes: Improving Forecasts with Storm-Following Nests

Alaka Jr, G. J., Zhang, X., & Gopalakrishnan, S. G. (2022). High-definition hurricanes: improving forecasts with storm-following nests. Bulletin of the American Meteorological Society, 103(3), E680-E703.

Abstract: To forecast tropical cyclone (TC) intensity and structure changes with fidelity, numerical weather prediction models must be “high definition,” i.e., horizontal grid spacing ≤ 3 km, so that they permit clouds and convection and resolve sharp gradients of momentum and moisture in the eyewall and rainbands. Storm-following nests are computationally efficient at fine resolutions, providing a practical approach to improve TC intensity forecasts. Under the Hurricane Forecast Improvement Project, the operational Hurricane Weather Research and Forecasting (HWRF) system was developed to include telescopic, storm-following nests for a single TC per model integration.

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View of a sunset, clouds and a wing from a Hurricane Hunter aircraft.

Women’s History Month with Leaders from the Hurricane Research Division

In honor of Women’s History Month, NOAA’s Atlantic Oceanographic and Meteorological Laboratory (AOML) would like to recognize two of our female leaders within the Hurricane Research Division (HRD), Heather Holbach and Shirley Murillo. We talked to these incredible scientists to learn more about their leadership roles within the division and to seek out any advice they have for women early in their science career.

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