我国近40年各类降水事件的变化趋势

 利用全国542站1960-2003年逐日降水资料，分析我国降水事件的变化趋势，研究结果表明：降水总量的增加主要是由极端降水量的增加引起，降水日数的减少主要是由小雨日数的减少造成。在降水日数呈现出大范围减少趋势的同时，有很多地区的极端降水事件仍为增加趋势，降水总日数的减少并不减小发生极端事件的可能性。各种类型降水日数趋势变化最明显的是小雨日数，四季的小雨趋势以减少为主。四季西部地区的极端事件基本均呈现出显著的增加趋势；江淮华南地区的减少趋势主要出现在秋季，其它三季以增加趋势为主；华北、东北地区在冬季基本均为增加趋势，其它季节增减参半。极端降水量与降水总量的比值表现为全国普遍增加的趋势，说明我国四季降水量均有向极端化方向发展的趋势。

Trends in All Kinds of Precipitation Events in China over the Past 40 Years

Based on daily rainfall dataset of 542 stations in China during the period of 1960-2003, the trends in all kinds of precipitation events in China are briefly studied in this paper. The results show that.the increasing total precipitation amount is mainly caused by the rising extreme precipitation (EP), and the reducing sprinkle frequency is the major reasons of the decreasing rain days. A decrease in rain days is observed in most regions of China, and EP events still have increased trends in many areas at the same time, so the lessening rain days could not reduce the possibility of EP. The trend of the sprinkle frequency is the most obvious change in all kinds of precipitation events, and declining is the main trend throughout most parts of China. A significant increase in EP events is observed in western China in all seasons. The EP events have decreased in the Yangtze River and southern China in autumn, but increased in the other three seasons. In northern and northeastern China, EP events show an increase in winter and a half increase in the other seasons. The ratio of EP amount to total precipitation amount is generally increasing in most areas of China,suggesting that the precipitation event has an obvious trend of extremeness.