Temperature and salinity extremes from 2014-2019 in the California Current System and its source waters

The California Current System in the eastern North Pacific Ocean has experienced record high temperatures since the marine heatwave of 2014-2016. Here we show, through a compilation of data from shipboard hydrography, ocean gliders, and the Argo floats, that a high-salinity anomaly affected the California Current System from 2017-2019 in addition to the anomalously high temperatures. The salinity anomaly formed in 2015 in the North Pacific Subtropical Gyre and was subsequently advected into the California Current System, in a generation mechanism different from the events leading to the marine heatwaves of 2013/2014 and 2019 in the North Pacific. The salinity anomaly was unique in at least 16 years with an annual mean deviation from the long-term average greater than 0.2 and anomalies greater than 0.7 observed offshore. Our results imply that different source waters were found in the California Current from 2017-2019, with the near-surface California Current salinity rivaling that of the California Undercurrent. A substantial positive salinity anomaly affected the California Current System in the eastern North Pacific Ocean from 2017-2019 and may indicate a change in source waters, according to a compilation of shipboard, ocean glider and Argo float data.

Automated summary

A study found that the California Current System in the eastern North Pacific Ocean experienced a substantial positive salinity anomaly from 2017-2019, indicating a potential change in source waters.