장강 담수방류에 기인한 여름철 동중국해 해면수온 상승

Abstract

Freshwater flux into the ocean induces a surface warming through forming a barrier layer (BL) which enhances the upper ocean stratification and reduces vertical mixing. This study explores effects of the Changjiang river discharge (CRD) on the density stratifications and associated sea surface temperature (SST) changes using an ocean general circulation model focusing on the Yellow and East China Seas (YECS). An experiment considering year-to-year variation of the CRD from 1960 to 2001 shows that the CRD tends to increase SST in August. Correlation analysis for SST with the stratification at the mixed layer base and the BL thickness demonstrates that the CRD-induced warming is attributed to the BL process. This result suggests that the BL induced by the CRD would be an important contributor to surface heat budget in the YECS although the warming is estimated relatively small probably due to bulk formula that tends to reduce the warming. An approach using a coupled ocean-atmosphere model with higher resolution would clarify the contribution of the BL process to the surface warming.