近50年西南地区降水的时空分布特征

Spatial and Temporal Distribution Characteristics of Precipitation over Southwest China in the Past 50 Years

摘要: 利用1960~2014年的西南地区93个站的逐月降水资料，统计分析了西南地区(95˚E~111˚E, 20˚N~35˚N)全年和春、夏、秋、冬季降水的时空分布特征。取得主要结论如下：1) 降水时间分布上，西南地区夏季降水最多；而冬季降水最少。同时西南地区全年和夏季降水量在1968年最多，而在2011年最少；春季降水量在1990年最多，而在1979年最少；秋季降水量在1982年最多，而在2009年最少；冬季降水量在1969年最多，而在2009年最少。2) 降水空间分布上总体存在三个特点：一是西南地区降水有从东到西递减的趋势；二是川西高原为少雨区并且在四川中部有一多雨区；三是西南地区夏季是多雨季，而冬季是少雨季。3) 对西南地区降水的EOF分析而言，我国西南地区全年、春季、夏季、秋季和冬季降水第一模态在空间上都表现为全区一致性，具有下降的年际变化特征。

Abstract: Using monthly precipitation data from 93 stations in southwest China from 1960 to 2014, the spa-tial and temporal distribution of precipitation in spring, summer, autumn, winter and annual in southwest China was statistically analyzed. The main conclusions are as follows: 1) In terms of precipitation time distribution, summer precipitation is the most, and winter precipitation is the least. The annual average and summer precipitation in the southwest was the highest in 1968, and the lowest in 2011; Spring precipitation was the highest in 1990 and the lowest in 1979; Autumn precipitation was the highest in 1982 and the lowest in 2009; Winter precipitation was the highest in 1969 and the lowest in 2009. 2) There are three characteristics in the spatial distribution of precipitation: first, there is a trend of decreasing precipitation in southwest region from east to west; second, the western of Sichuan plateau is a less rain area and there is a rain-prone area in central of Sichuan; third, southwest region summer is a more rain season, but winter is a less rain season. 3) For the EOF analysis of precipitation in southwest China, the first modal of annual, spring, summer, autumn and winter precipitation in southwest China is consistent in space and has the characteristics of declining inter-annual variation.