Abstract
Comment
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Oral or Poster
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IAPSO
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JMP06 - Advancing air-sea flux process understanding across diverse conditions
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Investigating the relationship between wind stress, drag coefficient and surface waves under hurricane conditions measured by the Uncrewed Surface Vehicle Saildrones
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1. Dongxiao , Zhang*, CICOES/University of Washington and NOAA/Pacific Marine Environmental Laboratory
2. Gregory , Foltz , NOAA/Atlantic Oceanographic and Meteorological Laboratory
3. Chidong , Zhang, NOAA/Pacific Marine Environmental Laboratory
4. Lev , Looney , CIMAS/University of Miami and NOAA/Atlantic Oceanographic and Meteorological Laboratory
5. Jun , Zhang, CIMAS/University of Miami and NOAA/Atlantic Oceanographic and Meteorological Laboratory
6. Andrew , Chiod , CICOES/University of Washington and NOAA/Pacific Marine Environmental Laboratory
7. Meghan , Cronin , NOAA/Pacific Marine Environmental Laboratory
8. Elizabeth , Thompson , NOAA/Physical Sciences Laboratory
9. Jim , Thomson , APL/University of Washington
10. Nan-Hsun , Chi , CICOES/University of Washington and NOAA/Pacific Marine Environmental Laboratory
*Presenting Author
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Tropical cyclones (TCs) and hurricanes are among the most extreme oceanic and atmospheric events originating from tropical oceans, often causing significant loss of life and property upon landfall. Predicting TCs, particularly their rapid intensification, remains a major challenge for numerical forecasting models. While surface turbulent heat flux fuels hurricane intensification, momentum flux (or wind stress) transfers kinetic energy from the storm to the ocean, influencing ocean mixing and stratification, which in turn affect sea surface temperature and heat flux. The balance between surface enthalpy flux (the sum of sensible and latent heat flux) and drag plays a critical role in TC and hurricane intensification. Due to the lack of direct observations inside the TCs and hurricanes near the air-sea interface, studies largely based on numerical models, lab experiments, air-deployed dropsondes, and indirectly from momentum budget analysis, have suggested a significant deviation of wind stress and drag coefficients at high wind speeds exceeding 20 m/s under TC and hurricane conditions. Since 2021, NOAA/AOML and PMEL, together with Saildrone, Inc., have deployed 5-12 Saildrone Uncrewed Surface Vehicles (USVs) each year during the hurricane season to intercept the TCs and hurricanes in extreme wind and sea states. The 1-minute and 5-minute averaged data are telemetered in real time to the WMO Global Telecommunication System (GTS) providing data access to the international forecast centers. The high-resolution 20-Hz motion-corrected 3-dimensional winds and GPS-aided Inertial Measurement Unit (IMU) data are made available upon the return of Saildrone USVs after the hurricane season. Here, we use these high-resolution data to compute the Eddy Covariance wind stress, drag coefficient, and directional wave spectrum, and to investigate the complex relationship between the wind stress, drag coefficients, and ocean waves.