The influence of varying bathymetry on inertial boundary currents

Open Access
Publisher Website
Google Scholar
Abstract
The response of steady oceanic boundary currents to topographical forcing is examined by a simplified inviscid one-layer model on a beta-plane. The currents are confined between a solid vertical boundary on one side and a free streamline, beyond which the ocean is motionless, on the other. Approximate solutions for both zonal and meridional currents are obtained using power series expansions in the ratio between the width of the current to the length scale of the topography. It is found that upon encountering a longitudinal ridge, an eastward flowing current confined between a solid vertical boundary on the left (north) and a free streamline on the right (south) may deflect to either direction (toward or away from the coast) depending on the Rossby number, the relative depth change and the variation of the Coriolis parameter with latitude. In mid-latitude a small Rossby number flow narrows and deflects northward as it crosses a ridge in the northern hemisphere. By contrast, when the current is located close to the equator, the ridge causes broadening and a southward deflection. Consequently, there exists a latitude at which a given decrease in depth does not cause any deflection. Similarly, a meridional southward flowing current confined between a solid wall on the left (east) and a free streamline on the right (west) intensifies and deflects eastward or broadens and deflects westward depending on the range of parameters. The parameters of both zonal and meridional currents may combine in such a way that the currents turn sharply away from the coast. Under certain conditions, the sharp turning is associated with a separation of the current from the coast and a subsequent formation of a “blocked” region near the wall. DOI: 10.1111/j.2153-3490.1980.tb00955.x

This publication has 11 references indexed in Scilit: