SASCWATCH: Study on Air-Sea Coupling with WAves, Turbulence, and Clouds at High winds

Air-sea fluxes at high winds have long been highly uncertain due to the complex processes involved and the difficulties in making observations in hazardous conditions, yet their characterization is crucial for understanding and forecasting extreme weather events such as tropical cyclones (TCs). Despite decades of dedicated research, roadblocks in two key areas continue to plague efforts in reducing uncertainty in the high-wind air-sea flux coefficients needed for accurate model forecasts: surface waves and boundary layer turbulence. Within TCs, neither the surface wave spectral properties nor near-surface turbulence statistics have been directly characterized in a comprehensive way, and many efforts to estimate fluxes rely on inferences or untested assumptions. The next frontier in understanding the complex ocean-wave-atmosphere coupled system requires a detailed investigation of turbulence and waves within TCs, using a suite of observational and simulation tools. These include ocean drifters with wave measurement capabilities, uncrewed aerial drones for measuring direct fluxes in the boundary layer, coupled wind-atmosphere-ocean mesoscale modeling, reduced-order TC models and data assimilation, and turbulence- and spray-resolving simulations. This presentation will provide an overview of the recently begun SASCWATCH project, including the motivations for such a study, details on the observational and simulation strategies, current findings, and future potential.