Lag impacts of the anomalous July soil moisture over Southern China on the August rainfall over the Huang–Huai River Basin

Abstract The effect of soil moisture (SM) on precipitation is an important issue in the land–atmosphere interaction and shows largely regional differences. In this study, SM ERA-Interim reanalysis data weather stations were used to investigate their relationship over eastern China during July August. Moreover, WRF model was applied further validate rainfall. observations, a significantly negative found that, when southern wet (dry) July, rainfall decreases (increases) Huang–Huai–River basin (hereafter HHR) results, can “memorize” its anomaly from August, increases latent heat flux at surface air lower levels atmosphere, which generally unstable due summer monsoon. Thus, upward motion prevailing increased transported upwards. After condensation water vapor enhanced middle upper levels, increasing release atmosphere. forms cyclonic circulation China, induces transport convergence This strengthens levels. Therefore, positive feedback appears between atmospheric circulation. Meanwhile, results response divergence downward HHR. Consequently, anomalies occur HHR When dry opposite be through similar mechanism.