STEADY AND TRANSIENT FLOWS AROUND BANKS LOCATED NEAR A SHELF EDGE

Barotropic and baroclinic flows around isolated banks located near a shelf edge are investigated. Simple models of longshelf currents have been explored both with analytical and numerical methods. The topographically-induced flow near the bank is found to depend crucially on the direction and the spatial distribution of the current. For a northward current with the coast to the right (northern hemisphere) the current speed is enhanced on the shelf slope side of the bank with an anticyclonic circulation over the central bank plateau. For a southward current with the coast to the left current enhancement takes place along the coast and stationary continental shelf waves appear in lee of the bank near the shelf edge. The transient barotropic response due to forcing by windstress and atmospheric pressure gradients associated with travelling storms has been studied by numerical simulations. This example shows that the induced shelf wave oscillations are strongly modified in the vicinity of the bank. Current records from Haltenbanken on the Norwegian continental shelf are reviewed and the data indicate generation of an anticyclonic eddy over the bank plateau and enhancement of shelf edge current in accordance with the model predictions.