Near-inertial energy propagation from the mixed layer: theoretical considerations

Abstract

Wind-generated inertial currents can radiate from the mixed layer as horizontally and vertically propagating near-inertial internal gravity waves. To study the timescale of the decay of mixed layer energy and the magnitude of the energy transfer to the ocean below, the authors developed a numerical, linear model on a β plane, using baroclinic modes to describe the velocity field. The numerical results are interpreted using concepts of modal interference and modal departure that can be evaluated analytically, thereby permitting predictions of some features of wave field evolution without the need to run the numerical model. The energy exchange with the pycnocline and deep ocean is explored as a function of the propagation speed and direction of the front, the horizontal extent of the storm, and the background stratification. -from Authors