AbstractInternal Tides in the Weddell-Scotia Confluence Region, AntarcticaSusan Howard, Laurie Padman, and Robin Muench. The Deep Ocean VEntilation Through Antarctic Intermediate Layers (DOVETAIL) program was designed to study the modification of dense water types formed in the Weddell Sea as they cross the northern boundary, defined by the Scotia Ridge, to enter the World Ocean’s deep circulation. DOVETAIL measurements indicate that the area surrounding the Scotia Ridge (the Weddell-Scotia Confluence) experiences enhanced vertical mixing. We hypothesize that the dissipation of internal tides generated when the barotropic tides interact with the rough topography of the Scotia Ridge is responsible for much of the mixing seen is this region. This hypothesis is tested using the 3-D primitive equation Princeton Ocean Model (POM) to simulate the generation and propagation of M2 and S2 internal tides at the Scotia Ridge. The model uses realistic stratification and bathymetry, and normal-flow open boundary conditions obtained from our Circum-Antarctic Tide Simulation model. Even though stratification is weak at the generation site, strong baroclinic tides are generated. Up to ~ 500 W m-1 of barotropic tidal energy is converted to baroclinic tides per meter of ridge length, consistent with previous estimates from an analytical model. The energy flux is directed south into Powell Basin and north into the Scotia Sea. In the Powell Basin, the upper water column shear and patchiness produced by the model agrees well with ADCP measurements taken during the 1997 DOVETAIL cruise. |