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

Alice S Ren,Daniel L Rudnick

doi:10.1038/s43247-021-00131-9

Alice S Ren, Daniel L Rudnick

Open Access

https://doi.org/10.1038/s43247-021-00131-9

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Abstract

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.

Highlights

The California Current System in the eastern North Pacific Ocean has experienced record high temperatures since the marine heatwave of 2014-2016
The salinity anomaly was noted in the annual report describing the physical and biological condition of the California Current System (CCS) organized and published by the California Cooperative Oceanic Fisheries Investigations (CalCOFI).[2,6]
The temperature in 2015 was the highest in the California Current based on the time series of almost 70 years

Summary

Introduction

The California Current System in the eastern North Pacific Ocean has experienced record high temperatures since the marine heatwave of 2014-2016. The salinity anomaly was noted in the annual report describing the physical and biological condition of the CCS organized and published by the California Cooperative Oceanic Fisheries Investigations (CalCOFI).[2,6] The relevance of regional salinity changes is that they often indicate changes of source water which may have a large impact on the marine ecosystem.

Results

Conclusion