The analysis on possible causes of spatio-temporal characteristics of Torrential Rain in Anhui Province

The spatio-temporal characteristics of precipitation amount, days and intensity of torrential rain are discussed by analyzing daily precipitation data of 16 stations in Anhui Province from 1960 to 2012. Meanwhile, bytaking advantage of torrential rain index, the atmospheric circulation and sea surface temperature are analyzed under different spatial modes. The results showed that the rainfall amount, days and intensity are all greater in the south than in the north of Anhui province. From June to August, torrential rain area moves from south to north progressively. There are significant monthly variations and regional differences. The spatial modes of torrential rain index is divided into three categories: the first mode called consistent type indicates that the rainfall is consistent in all areas, the second mode called north-south type indicates that the rainfall is opposite in north and south, and the third mode called intermediate type indicates that the central part is different from that in south and north. These three spatial modes shown above accounts for 41.5%, 22.6%, and 15.1%, respectively. East Asia-Pacific teleconnection (EAP) is related to theconsistent mode, and its negative phase corresponds to strong torrential rain index years, and vice versa. Meanwhile, the mode has a positive correlation with SSTA in key area of Oyashio current of previous winter, and the correlation maximum appears in January. The north-south mode is related to the extent of cold air toward south and vertical movement.