The Weather and Its Circulation in Summer of 2006

The main weather processes and their circulations in summer 2006 are introduced.The severe flooding occurred in South China,Huaihe basin and Northeast China,however,the typical circulation and the related strong precipitation during Meiyu period over the Yangtze River basin did not appeared.The severe heavy rainfall over South China in June was caused mainly by shear line at the lower troposphere and stationary front at surface,and the heavy rainfall in July and August was produced by typhoon.In the Meiyu season of 2006,the blocking high located to the west of Baikal Lake,the west Pacific subtropical high was more northward than that in the normal year.The heavy rainfall in North China is closely related to the activities of low trough and cold front.The vortices are very active over northeastern China in the summer of 2006.The landing tropical cyclones with high intensity were more than normal and resulted in serious disasters.The heat wave days over southwest China in the summer of 2006 are much more than that in the summer of 2005,and swelter weather also occurred over North China.In addition,heat wave days did not happen over northeastern China.The heat wave occurred in southern China,which was associated with subtropical high of West Pacific and continental high,respectively.