An effect of ENSO on summer surface salinity in the Yellow and East China Seas

The Yellow and East China Seas (YECS) has been known to exhibit interannual variability in both physical and biological aspects, in relation with El Niño-Southern Oscillation (ENSO). This paper investigates the interannual variability of summer sea surface salinity (SSS) in the YECS and its linkage with ENSO, using a global ocean general circulation model (OGCM) with a regional focus on the YECS. The OGCM experiment reveals that the dominant interannual variability of the SSS in the YECS is attributed to a variability of the Changjiang river discharge (CRD). The variability of the CRD is linked to ENSO-related precipitation over the Changjiang river; when El Niño events occur in winter, precipitation over the Changjiang river increases in the rainy season of the following years. The increased precipitation in El Niño years results from enhanced southwesterly moisture flux from the South China Sea into southern China. Our finding suggests that ENSO-related precipitation in southern China contributes to the dominant interannual variability of the summer SSS in the YECS by modulating CRD.