Spatial and temporal variations of annual precipitation during 1960-2010 in China

China is situated in the East Asian Monsoon zone, and the heterogeneity of the temporal and spatial characteristics of precipitation might result in serious flood and drought disasters. Based on precipitation data from 1840 stations across China, the empirical orthogonal function (EOF) analysis and the rotated empirical orthogonal function (REOF) analysis were used to analyze the spatiotemporal characteristics of precipitation variations in China in 1960-2010. Results showed that: (1) precipitation in the East China witnessed changes in the late 1970s, from the late 1980s to early 1990s, and in the early 21st Century respectively, featuring the recurrent south-north shifts of the rainbelt in both directions. Precipitation in Northwest China experienced an abrupt change in the mid-1980s, showing that the western part of Northwest China became wet from the previous dry conditions, whereas the eastern part of the region became dry from the previous wet conditions. However, precipitation in Northeast China underwent abrupt changes in early 1980s and late 1990s respectively, when precipitation changed from near normal in the previous period to more than normal in early 1980s and from more to less than normal in late 1990s. Evident phases in changes in precipitation had been detected over Southwest China, showing that the precipitation changes over both western and northeastern parts of this region were almost opposite; (2) decadal changes of precipitation in East China were closely correlated with the East Asian summer monsoon and the atmospheric circulation, while as important external forcing factors, the Pacific SST and snow cover on the Tibetan Plateau also had indirect impacts on the precipitation in the region through their influences on the East Asian summer monsoon and the atmospheric circulation.