Global tidal residual mean circulation: does it affect a climate OGCM?

A global description of the ocean tidal residual mean circulation (TRMC) is provided and its effect on a global ocean climate model is evaluated. The TRMC is computed from a global barotropic tidal model based on pure hydrodynamical equations and forced by the major tidal constituents. It thus includes both Stokes drift and non-linear tidal dynamics. The TRMC map exhibits remarkable basin scale structures in the Indonesian archipelago-Australian region and on the Malvinas shelf. Regions of largest transport are characterized by sites of high tidal amplitudes, abrupt topography and western boundaries. Yet transport magnitudes remain at a few tenths of a Sverdrup. This TRMC is introduced as an external forcing in an ocean climate model. At equilibrium, the thermohaline structure and the poleward heat transport of the ocean are almost insensitive to the TRMC. It is concluded that the TRMC is negligible for climate purposes in an ocean climate model.