Wednesday, 8 May 2024: 9:15 AM
Seaview Ballroom (Hyatt Regency Long Beach)
Surface directional wave spectra measurements collected by Air-Launched Autonomous Micro Observers (ALAMO) floats deployed in four major hurricanes (Teddy in 2020, Ida in 2021, Ian in 2022, and Lee in 2023) and one extratropical cyclone (Epsilon in 2020) are analyzed in two parts. First, the surface wave observations made by the Wave-field Inertial Measurement System (WIMS) sensor contained in the ALAMO floats are compared to other in-situ and remote wave measurements. The in-situ platforms are an eXpendable Spar buoy, NDBC surface metrological buoys, directional wave spectra drifters, and the remote observations are from the Ka-band Interferometric Altimeter (KaIA) and the Wide Swath Radar Altimeter (WSRA) aboard the NOAA Hurricane Hunter aircraft.
Next, the evolution of the directional wave spectra during hurricane passage is evaluated with respect to the local wind and to cyclone characteristics. The alignment of the directional wave spectra and local wind is found to vary by frequency and proximity to the storm center, a result echoed in the evolution of along- and across-wind mean square slopes. These results are then stratified by storm characteristics, such as tropical cyclone intensity, storm structure, and translation speed. The implications of this are discussed in the context of surface wave roughness and the drag coefficient.
Finally, these results are placed within the context of the Training and Research in Oceanic and atmospheric Processes In tropical Cyclones (TROPIC) field program. This joint capability test, demonstration, and integration program spanned more than a decade and was conducted by the United States Naval Academy, Woods Hole Oceanographic Institution and Air Force 53rd Weather Reconnaissance Squadron in concert with the Naval Oceanographic Office, Naval Research Laboratory – Monterey, National Data Buoy Center, and University of Washington Applied Physics Laboratory.
Next, the evolution of the directional wave spectra during hurricane passage is evaluated with respect to the local wind and to cyclone characteristics. The alignment of the directional wave spectra and local wind is found to vary by frequency and proximity to the storm center, a result echoed in the evolution of along- and across-wind mean square slopes. These results are then stratified by storm characteristics, such as tropical cyclone intensity, storm structure, and translation speed. The implications of this are discussed in the context of surface wave roughness and the drag coefficient.
Finally, these results are placed within the context of the Training and Research in Oceanic and atmospheric Processes In tropical Cyclones (TROPIC) field program. This joint capability test, demonstration, and integration program spanned more than a decade and was conducted by the United States Naval Academy, Woods Hole Oceanographic Institution and Air Force 53rd Weather Reconnaissance Squadron in concert with the Naval Oceanographic Office, Naval Research Laboratory – Monterey, National Data Buoy Center, and University of Washington Applied Physics Laboratory.
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