2009～2010年长江上游地区旱情成因分析

Genetic analysis of drought in upper Yangtze River regions from 2009 to 2010

针对2009～2010年秋冬季我国西南地区发生的历史罕见旱情,以及其持续时间长、影响范围广、干旱程度重等特点,用降水距平PAI指数、无雨日指数及江河水库来水量距平百分率对其干旱程度作了初步分析,并分析了干旱等级。结果表明,2009年秋季开始的西南地区干旱估计为100 a一遇。通过对长江上游地区干旱成因分析认为,大范围、持续时间长的严重干旱都是在特定的气候背景条件及大气环流异常情况下发生的。

Aiming at the severe drought in autumn and winter from 2009 to spring of 2010 in south-west regions of China,which has rarely occurred in history,we analyze the extent of the drought using PAI index of precipitation anomaly,index of rainless days and anomaly percentage of inflow of the reservoirs on the rivers in this region.The results show that the drought began in autumn of 2009 in south-west China is of 100-year frequency.The genetic analysis indicates that the large-scaled and long-duration drought may occur under certain climate condition and abnormal atmospheric circulation.