This study will investigate the exchange of energy between the atmosphere and the ocean and the role that ocean waves play in this. Unprecedented measurements of the mean, wave-driven and turbulent motions on both the air and water side of the sea surface will be made from a fixed tower with a vertical array of high-resolution velocity and pressure sensors, and complemented by wave measurements, high-resolution sea-surface imagery, and an array of wave buoys. The deployments will be in Pamlico Sound, NC, a shallow fetch-limited basin that is protected from oceanic swell and has weak tides, which will serve as a natural laboratory for this research. A comprehensive data set will be collected during two three-month long deployments in the fall of 2021 and 2022, when strong winds produce energetic young waves that are the focus of this study. The data collected will be used for the development of air-sea interaction parameterizations for use in models that couple the atmosphere, waves, and the ocean. These parameterizations are used in models that span a large range of research, engineering, and planning applications including physical oceanography, meteorology, climatology, coastal and estuarine engineering and sciences, polar research, and others. Data collected in this study will be used for student data analysis projects in a new air-sea interactions class taught in the WHOI/MIT joint program. The PIs will also participate in the Skype a Scientist program, which will provide opportunities to communicate with middle and high school students from around the world about basic topics related to science. A graduate student will receive interdisciplinary training in oceanography and boundary layer meteorology and this project will support an early career scientist who will lead the project and gain valuable experience working with two experienced scientists.
The transfer of kinetic energy between the ocean and atmosphere figures prominently in weather systems and global climate, as well as controlling the exchanges of heat and gases, and driving currents and waves. These air-sea transfers take place in the oceanic and atmospheric boundary layers, which are significantly different from rigid boundary layers due to the presence of surface gravity waves. Although progress has been made in understanding these wave-affected boundary layers, the specific processes governing wave-mediated transfers of energy and momentum are not well understood. Studies have suggested that there is a deficit of turbulent dissipation in the atmosphere, which is assumed to be balanced by energy input to the surface waves by pressure work. Similarly, there is a turbulent dissipation surplus in the ocean due to wave breaking, and recent research suggests this surplus is the result of a convergence in energy flux also driven by pressure work. However, we lack a detailed mechanistic understanding of how these fluxes occur across the interface, including the extent to which the atmosphere and oceanic response is coupled under breaking waves. This project will make contemporaneous measurements in both the ocean and overlying atmosphere to: 1) test the hypothesis that the TKE dissipation deficit in the atmosphere balances the dissipation surplus in the ocean; 2) identify the mechanisms that drive these energy transfers from the atmosphere into the waves and from the waves into the ocean, and, 3) test a new model for the magnitude and vertical structure of TKE dissipation in the ocean.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.