Some effects of a seamount on oceanic flows

Abstract

Considers a uniform, two-layer flow passing a right circular cylinder of arbitrary height in a rotating fluid. This demonstrates some effects of a seamount on oceanic flows. The critical stratification has been derived, below which there may be overlapping Taylor columns, and hence possible ventilation of the layer if surface cooling occurs. For typical oceanic conditions, this critical stratification corresponds to a baroclinic deformation radius measuring about a half of the obstacle radius. By generalizing the model results to a multiple-layer fluid, mesoscale features similar to those observed over the Emperor Seamounts are deduced. When the model is applied to the Maude Rise in the Weddell Sea, it can explain the extensive ventilation of the water above the rise, with possible implications on the initiation and maintenance of the Weddell polynya. (after Author)