近47年中国夏季日降水变化特征分析

以中国596个气象台站1961~2007年的夏季逐日降水资料为基础，分析了近47 a中国夏季降水长期趋势和年代际变化特征。采用面积加权平均法得到夏季全国和8个区的降水量、降水频率、降水强度序列。按小雨、中雨、大雨及暴雨降水强度分类，探讨了不同强度降水在我国降水变化中的贡献。结果表明：中国总体夏季除降水频率呈减小趋势外，降水总量、降水强度都呈增加趋势；西北西部在8个区域中的变化相对显著。降水量的增加是小雨级别降水频率和中雨以上级别降水强度增加共同作用的结果；东北、华北、西北东部降水减少主要是小雨降水频率减少的结果；长江中下游和华南降水量增加主要是大雨、暴雨降水频率和暴雨降水强度增加共同作用的结果；西南降水减少主要是小雨降水频率减少的结果。各区及全国夏季降水量、降水频率和降水强度大多在90年代有所增大，在2000年后又有所减小。与1970年代末的气候跃变相对应，各区及全国降水频率、降水强度的跃变均发生在1970年代末或1980年代初。〖

ANALYSIS OF SUMMER DAILY PRECIPITATION VARIATION CHARACTERISTICS IN CHINA DURING 1961~2007

This paper analyzed summer precipitation trends and decadal variation based on daily precipitation data of 596 stations from 1961 to 2007 throughout China.The whole country and 8 sub regions’ mean series of precipitation amount,precipitation frequency,precipitation intensity of summer were calculated by using the method of area weighted average.The precipitation was categorized into four types according to the daily rainfall amount:01~99 mm/ d,100~249 mm/ d,250~499 mm/ d,and above 500 mm/d.Special attention were devoted to their contribution to the total precipitation variation in China.The results proved that the trend of China's overall summer precipitation frequency decreased,the trends of precipitation amount,precipitation intensity increased.The change of the western northwest China Region was comparatively remarkable,and three indices showed significant increase in the trends.The increase of precipitation resulted from the increased light rain frequency and moderate rain ,heavy rain,torrential rain intensity.In northeast,north and eastern northwest China,the decrease of precipitation resulted from the decrease of light rain frequency.The increase of precipitation in mid lower Yangtze basins and south China resulted from the increase of heavy rain,torrential rain frequency and torrential rain intensity.The decrease of precipitation in southwest resulted from the decrease of light rain frequency.In eight districts and China,most of the precipitation amount,precipitation frequency and precipitation intensity increased in 1990s and decreased in 2000s.In response to the decadal shift of East Asian climate in the late 1970s,the decadal shift of precipitation frequency and intensity in 8 sub regions and China all occurred in the late 1970s or early 1980s.〖