Satellite Tracking of Episodic Low Sea Surface Temperature and High Chlorophyll-a Levels off the Northeastern Coast of Korea

Abstract

The study traced episodic low sea surface temperature (SST) and high chlorophyll a (Chl-a) concentrations off the northeastern coast of the Korean Peninsula, a region that is difficult to access, in 2017. For this analysis, NPP/VIIRS SST, COMS/GOCI Chl-a, and MetOp/ASCAT sea surface wind (SSW) data were used for South Hamgyeong Province, on the northeastern coast of the Korean Peninsula. In winter, low SST and high Chl-a levels were continuously observed in the East Korea Bay, with northwesterly or westerly winds. In March and April, low SST and high Chl-a levels were sometimes observed near Hamheung, occasionally extending to Sinpo. From May 4 to 7, southwest winds (2.2–11.5 m/s), low SST, and high Chl-a levels were observed along the coast from Hamheung to Kimchaek. In June, these trends continued only near Kimchaek, where westerly and northerly winds converged; in July, similar but weaker trends were observed at Sinpo. From August to October, low SST and high Chl-a levels were not observed, but returned in November, when they were strongest in Hamheung and appeared continuously in Wonsan. SST and Chl-a levels were strongly negatively correlated in all seasons except summer. Low SST and high Chl-a levels seems to be associated with upwelling, convection and advection.