Future Changes in Eddy Kinetic Energy in the California Current System From Dynamically Downscaled Climate Projections

Abstract

Eddies in the California Current System (CCS) are generated via baroclinic instabilities of the upwelling jet and contribute to mesoscale variability. However, climate-induced changes in mesoscale activity of the CCS remain poorly explored. We present future eddy kinetic energy (EKE) from an ensemble of three high-resolution downscaled ocean projections covering 1980–2100. EKE is projected to increase throughout the CCS toward the end of the century (2071–2100) compared to a 1980–2010 reference period. Using measures of upper ocean stratification, we find an increasing EKE trend is highly correlated with a more stratified ocean. These findings support previous studies suggesting that mesoscale activity is modulated mainly by baroclinic instabilities, rather than changes in the wind components, which did not show a systematic change across the three projections. Enhanced eddy activity could lead to changes in the distribution and aggregation of biogenic material, having important implications for the CCS.