Spatial and temporal variability of the California Current identified from the synoptic monthly gridded World Ocean Database (WOD).

Abstract The synoptic monthly gridded (SMG) world ocean database (WOD) were constructed with 1° × 1° horizontal resolution and 28 standard vertical levels from the surface to 3000 m deep using the optimal spectral decomposition technique. Monthly acceleration potential (AP) relative to 1000-dbar is calculated for the isopycnal surface 26.4 kg m−3 from January 1960 to December 2014 to investigate the spatial and temporal variability of the California Current. A composite analysis was conducted to obtain the total-time mean AP field and the climatological monthly mean AP variability, which is two orders of magnitude smaller than the total-time mean. Residual data were used to examine interannual variations of the AP field. An empirical orthogonal function (EOF) analysis was conducted to analyze the AP anomaly data. The EOF-1 (40% variance) represents strengthening/weakening of the North Pacific Gyre and California Current. EOF-2 (20% variance) represents onshore/offshore geostrophic flow. The first principal component was negatively correlated with the PDO; the second principal component was negatively correlated with both the PDO and ENSO, which implied that the AP anomaly contains climate variability signals. [ABSTRACT FROM AUTHOR]