An Asymptotic and Stochastic Theory for the Effects of Surface Gravity Waves on Currents and Infragravity Waves
J. McWilliams
Oceanic surface gravity waves are approximately irrotational, weakly nonlinear, conservative, and have a much shorter time scale than oceanic currents and longer waves (e.g., infragravity waves) except where the primary surface waves break. This provides a framework for an asymptotic theory, based on separation of time (and space) scales, of wave-averaged effects associated with the conservative primary wave dynamics combined with a stochastic representation of the momentum transfer and induced mixing associated with non-conservative wave breaking. The theory will be described and illustrative applications to the oceanic surface boundary layer, coastal circulation, and littoral currents will be presented.
