Sea Surface Salinity Dynamics in the Bohai Sea Using MODIS Data.

Two linear regression algorithms were developed for the retrieval of summer and winter sea surface salinity (SSS) using the Moderate Resolution Imaging Spectroradiometer (MODIS) remote sensing reflectance (Rrs) products, together with in situ SSS measurements from the Bohai Sea. The proposed models were applied to MODIS monthly 4km Rrs data to study SSS variations of the Bohai Sea during 2003-2018. The coastal waters in Laizhou Bay, Bohai Bay, and Liaodong Bay were found to be fresher than in the Qinhuangdao sea area, Central Bohai Sea, and Bohai Strait. The SSS values in winter in the Bohai Sea were >31.00 psu and <31.50 psu as a whole. There is a rising trend of SSS in the coastal areas of the Bohai Sea, especially in the Liao River estuary, northern Weihe River estuary, northeast Luan River estuary and in the north part of ancient yellow river course.