Wind-forced variations in sea surface height in the northeast Pacific Ocean

Two and a half years of sea surface height (SSH) anomalies from the Geosat altimeter were analyzed. The interannual anomalies suggested large-scale changes in the intensity of the California and Alaska currents, with a weak California Current for the first year (1986-1987), which strengthened during the second year, partly by a diversion of flow from the Alaskan gyre into the California Current and partly by a decrease in SSH along the coast. In the California Current between about 36° and 46°N, the annual fluctuations in SSH showed westward phase propagation. Modelling results suggest that the California Current core propagates offshore during the year due to a combination of spatial variations in the wind stress curl field and the meridional variation of the Coriolis parameter. Some qualifications to these conclusions are discussed along with an examination of errors in both SSH and wind stress. -from Authors