A numerical study of the effects of wind forcing on the Chilean Current System

Abstract

A high-resolution, multi-level, primitive equation ocean model is used to examine the response of an idealized, flat-bottomed, eastern boundary oceanic regime on a beta-plane to both steady and daily-varying climatological wind forcing. The area of study is a coastal region within the Chile Current System from 22°Sto34°S. When steady wind forcing is used, an equatorward surface current and poleward flowing undercurrent develop. Eddies are also generated, with initial formation in the poleward end of the domain. When daily-varying wind forcing is used, there is large spatial variability in the oceanic response. A relatively weak poleward flowing undercurrent appears, first in the poleward part of the domain. An equatorward surface current also develops and intensifies during the upwelling season. Eddies are generated and develop farther poleward in the domain than in the first experiment. The eddies are largest in the equatorward end of the domain. The eddy motion is closely tied to seasonal influences, with cyclonic (divergent) eddies traversing towards areas of higher dynamic heights when there are divergent wind fields present, and vice versa. In addition to the currents and eddies, upwelling and cold filaments are evident in both experiments.