中文摘要：

基于ERA40（ECMWF）1958—2001年土壤湿度再分析资料和中国541站降水资料,通过观测分析揭示了华南春季土壤湿度异常与中国夏季降水的联系及其可能的物理过程。结果表明,春季华南土壤湿度与夏季华南（长江流域及其以北地区）降水呈正（负）相关;春季华南土壤湿度负（正）异常,夏季华南降水异常偏少（多）,而长江以北地区降水则偏多（少）。通过对春季华南土壤湿度异常年份对应的环流异常特征的诊断分析发现：土壤湿度负异常年,西太平洋副高位置明显偏西,华南地区对应异常的下沉运动和水汽辐散,导致该地区降水偏少;而长江中下游地区对应异常的上升运动和水汽通量的辐合,降水偏多;土壤湿度正异常年的情况大致相反。进一步的分析表明,春季华南土壤湿度与同期长江中下游及以北地区土壤湿度存在明显的负相关关系。春季华南土壤湿度负（正）异常年的同期华北到长江中下游区域土壤湿度为正（负）异常,将导致南部区域的地表温度异常升高（降低）,北部地表温度异常偏低（偏高）,并通过改变地表对大气的加热,引起夏季大气环流的异常,最终造成夏季降水异常。

英文摘要：

Based on the 1958—2001 ERA40 reanalysis soil moisture data and precipitation data of 541 stations in China,the possible linkage between the spring soil moisture anomaly in South China（Ism） and summer precipitation in China as well as its possible physical processes are investigated.Results show that the spring soil moisture anomaly bears a positive（negative） correlation with summer precipitation in South China,and more（less） precipitation does in the Yangtze River basin and regions to its north）.Less（more） precipitation happens in South China（the Yangtze River Basin and regions to its north when spring soil moisture in South China is less（more）.By diagnosis on the basic features of the atmospheric general circulation related to spring soil moisture anomalies,it is found that the West Pacific subtropic high（WPSH） moves westward in negative Ism years,and the abnormal descending and the water vapor flux divergence are found in South China,which result in less summer rainfall in this region.However,the abnormal ascending and the water vapor flux convergence are found in the Yangtze River basin,which lead to more summer rainfall in this region.Contrary is the case in positive Ism years.Further investigation suggests that the soil moisture anomaly in South China is negatively correlated with that in the middle and lower reaches of the Yangtze River and regions north to it.The negative（positive） anomalies of soil moisture in South China and the positive（negative） anomalies of soil moisture in the middle and lower reaches of the Yangtze River and regions north to it can result in the abnormal increase（decrease） of surface temperature in southern region,but the abnormal decrease（increase） in northern region,which will cause the anomalies of summer atmospheric general circulation and precipitation by changing the surface heating to the atmosphere.