Eddy‐induced sea surface temperature gradients in Eastern Boundary Current Systems

Many processes are known to influence the distribution of sea surface temperature (SST) fronts in Eastern Boundary Current Systems (EBCS), including wind forcing, mesoscale activity, flow instabilities and flow-topography interactions. Here, we used satellite observations to quantify the relative importance of one of these processes, mesoscale eddy activity, on the distribution of SST gradients in EBCS. Eddies are characterized by large SST and SST gradient anomalies in all EBCS. At the end of the upwelling season, eddy-induced SST gradients are dominant components of the full SST gradient offshore of 300 km from the coast, especially in regions of high eddy activity. Comparisons between eddy-induced and full SST gradients in the California Current System indicate that the offshore migration of mesoscale eddies plays a significant role on the seasonal widening of the region of high frontal activity. SST gradients associated with anticyclonic eddies are largest within 400 km from shore, while the signature of cyclones can extend for up to 700 km from the coast.