Wind, Waves, and Surface Currents: Interactions at Mesoscales and Submesoscales

Air-sea exchanges of momentum and kinetic energy involve interactions between wind and ocean surface currents, mediated by the effects of surface waves. The wind stress that transfers momentum into the ocean depends on the velocity difference between winds and currents. Wind stress is also hypothesized to depend on the height and steepness of wind-generated waves. Waves are advected by ocean currents and also refracted as they pass through spatially varying currents. In turn, the impacts of waves and currents feed back on the wind, altering the structure of the atmospheric boundary layer. Together, wind-wave-current interactions shape ocean circulation, weather, and climate. However, gaps remain in our understanding, particularly in quantifying feedbacks between the components. Advances in our understanding will be facilitated by simultaneous measurements of key variables, via in situ observation or future satellite systems capable of obtaining global-scale observations.