Observations of the California Countercurrent

Abstract

Results from moored current meters, 150 - 350 m, are discussed for a region over the continental slope off Cape San Martin, California from January 1979 to April 1980. Current vector time series were constructed from the data and compared to a local upwelling index . Progressive vector diagrams of the data were also constructed, and spectrum analysis was performed for alongshore and cross-slope currents. The California Countercurrent was found to be present in the study area during the entire period. Seasonally, the countercurrent was substantially stronger during the spring. Frequent current reversals and oscillations occurred between equatorward and poleward flow, less often at the nearshore station. Preferred low frequency energy peaks were found at periods of about 10 days. The intensity of the countercurrent increased with increasing coastal upwelling index, and the cross-slope flow also appeared to be related to the local coastal upwelling index.