Seasonal and Interannual Variations of the Changjiang Diluted Water in the East China Sea Observed by the SMAP Satellite

The seasonal and interannual variations of the Changjiang Diluted Water (CDW) in the southern Yellow Sea and East China Sea (ECS) are studied using the latest Soil Moisture Active‐Passive satellite observations of sea surface salinity during 2015–2021. The continuous microwave satellite remote sensing provides unprecedented mapping of the sea surface salinity distribution important for variability study. The seasonal and interannual variations of the salinity in the core of the summer CDW are found to be dominated by ocean advection. Significant interannual variations of the CDW expansions are identified in the years of 2015, 2016, and 2020. The expansion in 2015 is due to an anomalous intrusion of the Taiwan Warm Current into the nearshore Min‐Zhe coasts cleaving the fresh water offshore. The largest area of the CDW is found in the summer of 2016 and is dominated by oceanic advection, with the precipitation playing a secondary role. An eastward extension of the CDW is produced by shelf current advection in the summer of 2020. The July Ocean advection anomalies over the shelf are found to track the oceanic Niño 3.4 index closely, whereas the SSS anomalies have a poor correlation with the index, suggesting complicated dynamic processes controlling the SSS interannual variations.