The spatial and temporal distribution characteristics of summer precipitation in China from 1960 to 2012

Based on the summer monthly precipitation data of 310 stations from 1960 to 2012 in 8 regions of China,the spatial and temporal distribution characteristics of summer precipitation are analyzed by trend features index,Mann-Kendall mutation testing and spatial interpolation.Results show that in spatial and temporal,the summer precipitation of the mid-lower reaches of the Yangtze River,south China,northwest China and Tibetan Plateau showed an increasing trend.The summer precipitation of the mid-lower reaches of the Yangtze River and the west of northwest China showed a remarkable increasing trend and the summer precipitation of the two regions increased most in 1990s.The summer precipitation of northeast China,north China,Tibetan and southwest China showed a decreasing trend and the summer precipitation of northeast China and north China showed a remarkable decreasing trend and it decreased mostfrom 2000 to 2012in northeast China and it decreased most in 1980 sin north China.The summer precipitation increased most in Anhui province.It increased least in Shandong,Hebei,Shanxi,Yunnan and Sichuan province.The summer precipitation variation of the mid-lower reaches of the Yangtze River and the west of northwest China reached to the level of mutations.The abrupt points were 1986 and 1989.The summer precipitation showed the variation from the less to the more.The weakening of southeast summer monsoon may have an important role in the process of summer precipitation reducing in north China,northeast China and in the process of summer precipitation increasing in the Yangtze River and south China.The summer precipitation reduction of southwest China was related to the weakening of southwest summer monsoon.The strengthening of westerlies convective activity may have a leading effect on the process of summer precipitation increasing in northwest China.The terrain of Tibetan Plateau is complex and the summer precipitation of Tibetan Plateau is mainly influenced by the terrain.