AOSC Seminar by Dr. Xiaomin Chen, 10/16/2025
AOSC Seminar
Xiaomin Chen
University of Alabama, Huntsville
Title
Sustained and Gusty Winds During Hurricane Landfalls: Challenges and Advances
Abstract
Hurricane landfalls are associated with extreme wind hazards and cascading impacts. Accurate knowledge of near‐surface wind strength during landfall is crucial for risk communication, preparing coastal communities, and post‐storm rescue and assistance (e.g., by FEMA). Yet reliably estimating near-surface winds remains a major challenge, in part due to limited understanding of wind profiles within the internal boundary layer (IBL) that forms from abrupt surface roughness changes at landfall. This study addresses this gap by employing semi-idealized large-eddy simulations (LES) designed to mimic the landfall of Category-2 hurricane-force winds over a range of land surface roughness conditions.
Considering that hurricane intensity is defined by the maximum sustained wind speed at the National Hurricane Center, the first half of the seminar examines how different land surfaces influence vertical profiles of near-surface mean winds and turbulence properties within the coastal IBL. Given the IBL’s detachment from the flow aloft, the ability of coastal radars and radiosondes to capture this feature will be discussed. Uncertainties in 10-m wind estimates from various observation-based methods will be quantified for the first time. The second half focuses on wind gusts, leveraging the high-frequency LES output to assess their evolution in coastal regions. Although 10-m sustained winds quickly weaken to tropical-storm force inland, 3-s gusts can still reach EF-1 to EF-2 intensity, posing severe localized wind hazards. Processes responsible for producing these extreme gusts will be discussed. These findings can contribute to the advancement of probabilistic 10-m wind forecasting products, in line with NOAA’s Hurricane Forecast Improvement Project (HFIP) objectives
Bio
Dr. Xiaomin Chen’s research focuses on understanding the boundary layer processes that influence the intensity and structural changes of tropical cyclones, as well as the associated wind hazards during and after landfall. To achieve this, he integrates multi-platform observations—including aircraft, ground-based Doppler radars, and UAH MAPNet—with turbulence-resolving large-eddy simulations to enhance the modeling of boundary layer processes under hurricane conditions. His recently developed boundary layer scheme has been implemented into NOAA’s next-generation hurricane forecast model, Hurricane Analysis and Forecast System (HAFS), enhancing the accuracy of both intensity and structural forecasts. In recognition of this pivotal achievement, Dr. Chen received the AMS Banner I. Miller Award in 2026.
Contact
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AOSC Seminar
Pre-seminar refreshment: N/A
Seminar: 3:30-4:30pm, Room: ATL 2400(only when in-person)
Meet-the-Speaker: 4:30-5:00pm, Room: ATL 3400(only when in-person) [For AOSC Students only]
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