Internal tides and baroclinicity in the Southern Weddell Sea 2. Effects of the critical latitude and stratification

Tidal dynamics affect Antarctic Bottom Water and Ice Shelf Water production in the southern Weddell Sea and the general circulation and mixing. In this region, tidal dynamics were found to be extremely sensitive both to the proximity of the continental shelf-slope break to the critical latitude psi (crit) and to the existence of a shelf break front. If the continental slope was not in the vicinity of psi (crit) or a shelf break front was absent, generation of internal tides was negligible. Generation of internal tides was greatest when both a shelf break front was present and the continental slope was near and equatorward of psi (crit). When a shelf break front was present and the continental slope was near but poleward of psi (crit), a strong benthic response occurred. This response included development of benthic inertial oscillations at the continental shelf-slope break, increased benthic shear, a thicker benthic boundary layer, and increased benthic dissipation. A shelf break front with even a slight horizontal density gradient was found to significantly enhance internal tide generation and/or the benthic effects.