中文摘要：

利用中国西南地区103个气象观测站1961年1月1日-2010年12月31日的逐日降水量资料,采用旋转经验正交函数分解、突变分析、小波分析等方法对该地区近50年夏季降水的空间异常分布、演变规律、突变及周期特征进行了诊断分析.结果表明：西南地区近50年夏季降水标准化距平场可以划分为七个分区,并根据夏季降水的年代际变化特征将其归为五种类型,即明显增加型、缓慢增加型、平缓变化型、缓慢减少型和明显减少型.近50年夏季降水量在川东渝北和川西高原地区明显增加,而四川盆地则明显减少;贵北渝南和贵南桂北地区呈南北相反的缓慢增加（减少）趋势,云南地区呈东西相反的平缓减少（增加）趋势.夏季降水突变点多集中在20世纪70年代、90年代和21世纪初,且都存在一个准14年尺度的变化周期.

英文摘要：

Based on the daily precipitation data from Jan 1st, 1961 to Dec 31st, 2010 at 103 stations in southwest China, the spatial-temporal evolution characteristics of summer precipitation over southwest China were studied, applying the EOF, REOF, Mann-Kendall, and wavelet analysis methods. The results show that the summer standardized precipitation field in southwest China could be divided into 7 regions and classified into 5 types according to the inter-annual variation of summer precipitation, i.e, the dramatically-increased type, gradually-increased type, slowly-changed type, gradually-decreased type, and dramatically-decreased type. In the past 50 years, the summer precipitation increased dramatically in eastern Sichuan, northern Chongqing and western Sichuan plateau; however, it decreased distinctly in the Sichuan basin. In northern Cuizhou and southern Chongqing, the summer precipitation gradually increased, while in southern Guizhou and northern Guangxi it gradually decreased, pointing to a gradually increase （decrease） as a contrary trend between the south and north. At the same time, the summer precipitation showed a slow decrease （increase） as a contrary trend between the east and west of the entire Yunnan. The discontinuity points of the summer precipitation of each station almost concentrated in the early 1970＇s, the late 1990＇s and the beginning of the new century, and showed a quasi-14-year circle of periodic variation.