Abstract:
Using daily observations of precipitation for the period 1961—2006 in China, we chose the percentile based thresholds to define precipitation events with different intensities in this study. There is light rain, moderate rain, heavy rain and extreme rain. The characteristics of these effective precipitation events are analyzed in conjunction with trace rain events (<0.1mm/d). During 1961—2006, the annual precipitation decreased in southern Northeast China, the lower valley of the Yellow River, the Loess Plateau, and the upper valley of the Yangtze River, the areas with decreasing trends shrank as precipitation intensity increased, the decreasing of the total precipitation in Loess Plateau and the upper valley of the Yangtze River is closely related to significantly decreasing moderate rain; The annual precipitation generally increased in the middle and lower valleys of the Yangtze River, Southeast China and the area to the west of 100°E, which was mainly induced by the increasing heavy rain and extreme rain in the first two areas, and also by the increasing moderate rain in the third area. The annual total precipitation events generally decreased except at a few stations in Xinjiang; the annual effective precipitation events increased significantly in Northwest China while they generally decreased to the east of 100°E, the frequencies of moderate rain, heavy rain and extreme rain all increased in Northwest China with the largest increase for moderate rain events, while the decrease of light rain and moderate rain events dominated to the east of 100°E. The trace rain events generally decreased. The largest decreasing proportion occurred in winter and the lowest in summer. The decreasing proportion was obviously larger in northern China than in southern China, which is consistent with the distribution of temperature variation in China. For China as a whole, the precipitation significantly decreased for light rain while it increased for heavy rain and extreme rain; the occurrence decreased for light rain and moderate rain while it increased for heavy rain and extreme rain.