夏半年中国总降水、极端降水及台风降水的趋势分析

Trends in Total Precipitation,Extreme and Typhoon Precipitation over China in Warm Half Year

利用逐日气象台观测资料,对1961-2010年夏半年（5～10月）中国总降水、极端降水、台风降水进行了趋势分析.结果发现：（1）中国平均降水量显著增加主要是由于降水强度增强引起的,降水强度增幅大于降水频数的减幅;极端降水量显著增加主要体现为极端降水频数的增多,极端降水强度50年来并无显著变化.（2）台风降水量减少主要是由于台风降水频数减少引起的,台风降水强度增幅弱于台风降水频数减少的幅度.（3）极端降水对总降水的贡献大致以103°E为界,呈东高西低的空间分布,东侧受东亚夏季风的影响,东亚夏季风对极端降水有明显的加强作用,能达到全年总降水的10％左右;103°E西侧,极端降水的趋势对总降水增长趋势的贡献率为25％～50％,而东侧,总降水趋势主要受极端降水趋势的控制,极端降水趋势（包括增、减趋势）的贡献达50％～100％.（4）长江中游至西南地区和黄河中下游及环渤海地区的降水趋势与全国整体呈上升趋势不同,这些地区的降水呈显著下降的趋势,台风降水趋势显著减少导致这些地区极端降水减少,进而造成总降水的减少.

The inter-annual component of warm half year mean （May to October） precipitation,extreme precipitation,tropical cyclone （TC） or typhoon precipitation,is studied by trend analysis for the period 1961-2010.The rosults show that （1） The precipitation in China increased significantly mainly due to the enhancement of the intensity of precipitation.The increasing of the intensity is larger than the frequency of precipitation.The precipitation extremes in China increased significantly mainly due to the enhancement of the frequency of precipitation extremes,although the intensity has no change in the past 50 years.（2） The TC precipitation in China decreased mainly due to the reduction of the times of TC precipitation.（3） To the east of 103°E,the percentage of extreme precipitation in total precipitation is 10％ larger than that to the west.East Asian summer monsoon causes such difference.The precipitation of the trend of extreme rainfall in the trend of total rainfall is 25～50％ to the west of 103°E.It （both increasing and decreasing trends） is much larger to the east of 103°E,up to 50～100％.（4） Different from the most part of china,the trend of rainfall in the middle reach of the Yangtze River to the South-west of China,the middle and lower reaches of the Yellow River and the Bohai rim region is decreasing.The trend of TC rainfall contributes significantly to the trend of total rainfall in these regions.