Structure of an inertial deep western boundary current

Abstract

An inertial model of the deep western boundary current (DWBC) is presented where the cross-stream distribution of potential vorticity varies in a realistic fashion. The case of uniform potential vorticity, which has been solved earlier, is included for comparison. The potential vorticity distribution used in the mode1 is obtained from a hydrographic density section across the North Atlantic DWBC. The mode1 solutions using this distribution differ significantly from the uniform potential vorticity case. Most notably the current is wider and weaker with substantially reduced relative vorticity, more indicative of observed DWBCs. The addition of an exponential continental slope leads to a further constraint on the existence of the current. Finally, it is demonstrated how a topographic ridge can partially block the DWBC and give rise to recirculation of the deepest water, reminiscent of the deep flow near the Southeast Newfoundland Rise in the North Atlantic.