Analysis of Rainfall Anomalies in China in Summer 2012

The average precipitations were more than normal in northern China in summer 2012.The causes of precipitation anomalies were analyzed.Results showed that more warm and humid water vapor was transported continuously to northern China due to the stronger East Asian summer monsoon and the northward West Pacific subtropical high ridge.While shortwave troughs were in activities in the mid-high latitudes over the Eurasia in summer 2012,they brought about more cold airs,and the latter converged with the warm and humid airs from the South China Sea and the East China Sea in northern China,which contributed to the more precipitation above normal in northern China.In addition,early La Nina event and the PDO cold phase were the external forcing conditions to the precipitation anomalies in northern China.