[Characteristics and adaption of seasonal drought in southern China under the background of global climate change. I. Change characteristics of precipitation resource].

Based on the 1959-2008 precipitation data from 262 meteorological stations in southern China, this paper analyzed the change characteristics of seasonal precipitation trend coefficient, precipitation variability, and annual and decadal precipitation standardized anomalies in this region. In the study period, there was a great difference among the trend of quarter precipitation. In most parts of the region, the precipitation in spring and autumn presented a decreasing trend but that in summer and winter was in adverse; only in southwest part, a slightly different trend was observed. In the whole region, the probability of spring drought decreased, but that of summer drought, autumn drought, and winter drought increased. Spring drought often occurred in south and southwest parts, summer drought and autumn drought often occurred in south part and the middle, lower reaches of Yangtze River, and winter drought expanded from south part to south part and the middle, lower reaches of Yangtze River. The precipitation in spring and autumn was below the normal level after the 1980s, while that in summer and winter was below the normal level before the 1990s, above the normal level in the 1990s, and below the normal level since the 21st century. The decadal change of the seasonal precipitation standardized anomaly in each part of the region was basically consistent, i. e., decreased in autumn and increased in summer and winter.