Wave-Induced Mass Transport in the Oceanic Surface Layer

Abstract

The mean mass transport induced by surface gravity waves is investigated theoretically for a deep, rotating ocean with a constant eddy viscosity. The waves are periodic in time and have amplitudes that grow or decay slowly in space. The analysis is based on a Lagrangian description of motion, and the results are valid to second order in the wave steepness. An equation for the wave-induced mean Lagrangian mass transport in the oceanic surface layer is derived. It is demonstrated that there are two sources for the mean mass transport: (i) the form drag associated with the fluctuating wind stress normal to the wave slope and (ii) the horizontal divergence of the mean wave momentum flux. Using a spectral formulation for the wave amplitude, applications related to general ocean circulation models are discussed.