Numerical study of shelf water motion driven by the Kuroshio: barotropic model

Abstract

The barotropic response of the shelf and coastal regions south of Japan to short-term variations in the Kuroshio was studied numerically with an inflow-outflow model. The onshore-offshore movements of the stream axis of the Kuroshio due to changes in the upstream volume transport have an important effect on shelf and coastal circulations off the coast of Japan. When the Kuroshio comes near the shelf south of Japan, topographic eddies of about 1.0 X 10 "SUP 5" m diameter are produced on the shelf behind the capes by the separation of the Kuroshio from the subsurface tip of spurs at a depth of about 200 m projecting from the capes into the sea. On the other hand, when the Kuroshio moves away from the shelf, the eddies disappear. This imples that the periodic formation and disappearance of the eddies takes place on the shelf due to the combined effect of the short-term onshore-offshore movements of the Kuroshio axis and the irregular topography of the continental margin. Tracking numerous labeled particles in the calculated velocity field by the Euler-Lagrangian method clearly showed that a large amount of the Kuroshio water is trapped in the eddy on the shelf. (from authors' abstract)