Circulation in the Point Conception‐Santa Barbara Channel region

Abstract

During spring and early summer 1983, fifteen current moorings were deployed around the periphery of Santa Barbara Channel and over the continental shelf to the west, off Point Conception. Data from these moorings have been used to describe the regional circulation and to address problems of wind forcing and the spatial coherency scales for current fluctuations. The mean circulation in Santa Barbara Channel was dominated by a westward jet which occupied the northwestern portion of the Channel. Current and temperature fluctuations were generally well‐correlated among all locations around the Channel, and time lags suggested cyclonic propagation of events around the Channel. The time fluctuations were dominated by a relatively few low‐frequency events. It was impossible to determine exactly either the driving mechanisms for these events or their relationships to regional flow. The flow regime was considerably different off Point Conception than in the Channel. Locally wind‐driven upwelling was observed in both the mean and fluctuating flows, and the time scales of current variability (i.e., spectral shapes) mimicked those of the local winds. A dramatic change in the regime off Point Conception occurred in late May. Before the transition, currents and sea levels had been well correlated in time with both local and remote winds. After late May the relation to fluctuating winds was less clear and the alongshore structure of sea level variability had changed radically.