Processes Intensifying Air-Sea Mesoscale Air-Sea Coupling

Mark A Bourassa, Florida State University, Center for Ocean-Atmospheric Prediction Studies, Tallahassee, FL, United States and Qi Shi, Florida State University, Tallahassee, FL, United States
This study details the processes coupling the boundary-layers in the ocean and atmosphere, in the presents of surface currents and waves. Modeling provides insights regarding the atmospheric responses (changes of wind vectors, boundary-layer stratification, stress, and water vapor content) and their links to changes in wave characteristics and the ocean (upwelling, currents, and sea surface temperature). On large scales, this coupling is relatively mild because horizontal gradients in surface stress are weak. However, on the meso- and sub-mesoscales these gradients are much stronger and greatly strengthen this coupling. Gradients in sea surface temperature, surface currents and wave-related roughness have been shown to play roles in these coupling processes. The strengths of these coupling processes will be illustrated in the context of the Gulf Stream. The link between stress gradients and Ekman upwelling will demonstrate the intensification of coupling at smaller spatial scales. Observational assessments will be used to identify shortcomings in the modeled parameterizations, and provide insight into factors that should be considered in the next generation of high resolution coupled models.