Wave driven winds

The CBLAST low campaign highlighted the existence of low level wave driven wind jets when long wavelength swell runs under regions of low winds. Large eddy simulations have also shown the development of the wave driven winds. Here we develop a simple model of wave driven winds that clarify the role of turbulent and Coriolis forces in shaping the jet. We then use the understanding gained from the simple model to interrogate the ERA-40 data base to determine a global climatology of air-sea interaction and thence a climatology for the occurrence of wave driven waves. Based on this evidence, we expect wave driven winds to be a prevalent phenomenon in the tropical Pacific. The global picture that emerges is of waves taking momentum from the wind within the mid-latitude storm tracks. Some of this momentum is deposited locally into the ocean through wave breaking. The remainder propagates in the wave field into the sub tropics and is gradually lost, partly through generation of wave driven winds.