SST Forcing off California Coast and Its Relationship to the Decadal Variation of North Pacific

This study explores the characteristics of interannual and interdecadal air–sea interactions related to the Pacific Decadal Oscillation (PDO) over the different regions of the North Pacific based on the relationship between turbulent heat flux and sea surface temperature (SST) anomalies during 1958–2018. The results show that the atmosphere directly drives SST anomalies over the Kuroshio–Oyashio Extension and the SST anomalies force atmospheric circulation over the equatorial central and eastern Pacific on the interannual scale. On the interdecadal scale, SST anomalies are mainly driven via atmospheric circulation over the north center of PDO. However, the ocean is very important in forming SST anomalies off the California coast. Further analysis shows that the area off the California coast is one of the key areas of quasi-12-year oscillation in the North Pacific. The period is similar to the decadal oscillation of PDO. The anticyclone (cyclone) circulation off the California coast may be forced via the cold (warm) SST anomalies off the California coast. The other two important parts in the quasi-12-year oscillation in the North Pacific are the upwelling of the equatorial central Pacific and meridional wind stress anomalies in the subtropical eastern North Pacific.