The Enhancement of Upper Ocean Nutrients Concentration in the Peripheries of Two Anti-Cyclonic Eddies

The upper ocean nutrients concentration is found to be enhanced in the peripheries of two anti-cyclonic mesoscale eddies in the Western North Pacific (WNP) through using AVISO Sea Level Anomaly (SLA), a Bio-Geo-Chemical Argo (BGC-Argo) float, and merged, multi-sensor Sea Surface Temperature (SST) data. In the first eddy, which is near the coast, nutrients concentration in the upper layer is low at the core but high along the periphery. In the second eddy, which is near the extension of Kuroshio, nutrients concentration along the periphery is higher than the surrounding areas. The enhancement of nutrients concentration along the peripheries is perhaps mainly due to strong vertical mixing. The distributions of dissolved oxygen, temperature, and salinity show similar patterns as the nutrients. In the peripheries, dissolved oxygen concentration is low, indicating high production induced by the high concentration of nutrients.