Parameterizing Tidal Dissipation over Rough Topography

Abstract. The traditional model of tidal dissipation is based on a frictional bottom boundary layer, in which the work done by bottom drag is proportional to a drag coe-cient and the velocity cubed. However, away from shallow, coastal regions the tidal velocities are small, and the work done by the bottom boundary layer can account for only weak levels of dissipation. In the deep ocean, the energy flux carried by internal waves generated over rough topog-raphy dominates the energy transfer away from barotropic flow. A parameterization for the internal wave drag over rough topography is included as a dissipative mechanism in a model for the barotropic tides. Model results suggest that the inclusion of this dissipation mechanism improves hydro-dynamical models of the ocean tide. It also substantially in-creases the amount of modeled tidal dissipation in the deep ocean, bringing dissipation levels there into agreement with recent estimates from TOPEX/Poseidon altimetry data