Statistical behaviours of precipitation regimes in China and their links with atmospheric circulation 1960-2005

In this study, we comprehensively analysed daily precipitation time series of 590 rain stations in China covering 1960-2005. Ten indices were defined to evaluate changing patterns of precipitation regimes and trend detection was performed using Mann-Kendall trend test and linear regressive technique. For the sake of better understanding of underlying causes behind changing properties of precipitation regimes, we also investigated spatial and temporal variations of atmospheric circulation of water vapour flux. The results revealed different changing properties of precipitation events across China. Generally, wet tendency was identified in the south China and dry tendency in north China. Besides, slight wet tendency could be found in northwest China. In addition, increasing precipitation intensity could be observed mainly in the lower Yangtze River basin and the Pearl River basin. Remarkable seasonal shifts of wet/dry conditions were also detected in China: wet tendency in winter and dry tendency in summer. Furthermore, this study revealed good agreement between spatial distribution of precipitation regimes and water vapour flux, showing tremendous influences of water vapour flux on the precipitation changes across China. Regions east to 100 E were dominated by increasing water vapour flux in winter. Weaker East Asian Summer Monsoon was the main cause responsible for decreasing northward propagation of water vapour flux, causing different wet (dry) tendency in south (north) China. This study can provide theoretical evidence for effective water resource management and sound arrangement of agriculture activities on river basin scale under the changing environment across China. Copyright. (C) 2010 Royal Meteorological Society