Deep-water upwelling in the frictional western boundary layer

Abstract

The structure of a Stommel type of frictional western boundary layer in a thermally driven two-layer model is examined. Instead of specifying the interfacial upwelling a priori, it is calculated as part of the solution subject to the dynamic and thermodynamic constraints. It is shown that upwelling prevails in the western boundary. Scaling analysis indicates that upwelling within the western boundary layer is two orders of magnitude stronger than that in the ocean interior. Furthermore, the total amount of upwelling within the western boundary layer constitutes a substantial part of the basin-integrated upwelling. Thus, our results suggest that it is important to study the dynamic role of western boundary upwelling in ocean circulation models.