Tidal Mixing in the Southern Weddell Sea: Results from a Three-Dimensional Model

Abstract

Abstract A three-dimensional primitive equation ocean model is used to study the magnitude and distribution of tidal mixing in the southern Weddell Sea. The contributions of (i) semidiurnal barotropic constituents M2 and S2, (ii) internal tides, and (iii) diurnal barotropic tides are considered. Computed elevation cotidal charts are generally consistent with our knowledge and observations for the region. The model reproduces maximum semidiurnal tidal elevations of about 1.6 m and 1.0 m for M2 and S2, respectively. An internal tide of moderate strength is generated over the slope, propagating in the alongslope direction but rapidly dissipating. On the continental shelf, a thick benthic boundary layer (150 m) develops due to the proximity of the critical latitude for the M2 constituent. Typical M2 and S2 baroclinic tidal currents at the shelf break are 7 and 4 cm s−1, respectively. In general, the tidal currents produce strong mixing in the bottom boundary layer at the shelf break and on the shelf leading t...