Roles of August Kuroshio SST Anomaly in Precipitation Variation during September over Central China

Abstract

 Sea surface temperature anomaly (SSTA) in the Kuroshio region near the East China Sea (K-ECS) during August has been found to be closely related to the September precipitation anomaly over Central China (CC) in this study. The significant causality is identified from SSTA in K-ECS to anomalous rainfall over CC. When a negative SSTA occurs in K-ECS during August, its cooling effect on the overlying atmosphere lasting from August to September promotes the formation of anomalous anticyclonic circulation below 600 hPa above K-ECS and the southeast of China by weakening the local convection. The southerly in the west of this anomalous circulation transports more water vapor into CC. Eventually, the convergence of moisture provides favorable conditions for the generation of precipitation here. The responsive characteristics of the anomalous atmospheric circulation during September to a negative SSTA in K-ECS in August can be confirmed through numerical experiments. The above important long-term relationship suggests that SSTA in K-ECS during August could serve as a valuable predictor for September precipitation over CC.