中文摘要：

采用NCEP／NCAR1961--2006年的全球月平均海表温度和风场再分析资料，以及云南省汛期（6—8月）124个观测站的降水资料，运用相关分析、合成分析及两组样本平均值差异的显著性检验方法，研究前期1—5月南半球海表温度对云南汛期降水异常有影响的关键时期和关键海区，并用南半球海平面风场分析关键海区的海温异常对云南汛期降水异常影响的物理成因机制。结果表明，前期南半球海表温度与云南汛期降水相关显著，显著关键海区主要位于南半球西风漂流区的东南印度洋、澳大利亚南部、东太平洋的智利和秘鲁西海岸及西南大西洋的麦哲伦海峡。其中东太平洋秘鲁寒流区的智利和秘鲁西海岸是影响云南汛期降水最显著的关键区。诊断分析还表明，在东太平洋秘鲁寒流区的暖位相期，孟加拉湾地区的季风和赤道印度洋附近的越赤道气流及印度洋的西南季风减弱，反之则加强。

英文摘要：

Based on the reanalysis data of monthly mean global SST and wind from the NCEP/NCAR and the observation data of flood seasons in 124 stations of Yunnan province from 1961--2006 , we applied the analytical methods of correlation analysis and composite analysis and a significance testing method to two sets of samples of average differences in order to investigate into the influence of the southern hemispheric SST on the summer precipitation in Yunnan province from January to May to identify the key time and marine regions. Physical mechanisms are obtained by analyzing the influence of sea-level wind and the key marine regions on the precipitation during Yunnan＇s raining season. Results showed that there is indeed significant relationship between the southern hemispheric SST and Yunnan＇s summer precipitation. The key areas for influencing Yunnan＇s summer precipitation are mainly distributed in the southern hemispheric West Wind Drift, including the Southeast Indian, the southern Australia, the eastern Pacific west coast off Chile, Peru and the southwest Atlantic Magellan. And the most significant sea region is the west coast of Chile and Peru （cold-current areas of the eastern Pacific）. Diagnostic analysis results also showed that monsoons in the Bay of Bengal, a cross-equatorial flow in the Indian Ocean near the equator and southwest monsoon in India weaken during the warm phase of the Peru cold current in the eastern Pacific. Otherwise, they strengthen.