On the analogy between rigid plate motion and mean momentum transfer in surface gravity waves

Abstract

The transfer of mean momentum from surface gravity waves to Eulerian mean fluxes is investigated by modeling the total wave momentum (the Stokes flux) as a thin surface layer moving with the phase speed c of the waves and with a thickness Z derived from the divergence effect. The bulk of the fluid receiving momentum from the waves is modeled by a rigid lower layer acted upon by the virtual wave stress, where the latter is related to the form stress from the wind and the time rate of change in Z through −cdZ/dt. In addition, the effects of surface wind and bottom stress are included in the model. Through the combination with measurements, this robust model may yield information about the Eulerian fluxes when the ocean surface is covered by a combination of ice and oil, and the constitutive equations for the surface cover are not easily obtained.