Seasonal variation of the water mass along the Oregon‐northern California coast

Temperature and salinity data collected at five Oregon—northern California coastal stations from 1960 to 1971 are used to assess the influence of local processes in modifying the water mass along the coast. A bivariate model is constructed for the summer and winter seasons at each coastal station permitting a quantitative measure of the degree of importance of each process. In summer the dominant modifying process is different at each shore station with local heating, upwelling, and mixing with shelf/slope water and Columbia River water being the major factors. In winter rainfall and runoff is the dominant process along the coast except near the northern border where mixing with shelf/slope water occurs slightly more frequently. In winter offshore surface waters within 81 km of the coast have nearly the same T–S as the waters at the coast. In summer offshore surface waters become cooler and more saline in the shoreward direction with the coolest and saltiest water occurring at the coast.