中文摘要：

利用NOAA_ERSST海温资料、NCEP／NCAR再分析资料和中国160站降水资料，借用多种统计方法研究了夏季长江中下游地区降水与西北太平洋的耦合关系。奇异值分解（SVD）和相关分析显示出长江中下游夏季降水与西北太平洋夏季海表温度（以下简称“海温”）密切相关，而与其他海区没有明显的关系，并且这种关系主要反映年代际变化；夏季多变量经验正交函数展开（MV—EOF）分析结果证明夏季长江中下游降水、东亚-太平洋地区上空850hPa风场、西北太平洋海温之间存在显著的耦合模态，这种耦合模态反映出长江中下游夏季降水异常偏多时，东亚-太平洋上空自南向北有异常的反气旋、气旋、反气旋波列（即东亚太平洋型遥相关或P—J波列），东亚夏季风偏弱、北界位置偏南。依赖季节的多变量经验正交函数展开（SRMV-EOF）分析结果表明，长江中下游夏季降水与西北太平洋的耦合模态与前期ENSO密切相关：前一年秋季，赤道东太平洋开始出现ENSO信号，冬季发展成熟，同时在菲律宾以东的西北太平洋上空有一个反气旋形成；春季，ENSO开始减弱，西北太平洋出现暖海温异常，反气旋发展；夏季，ENSO信号消失，西北太平洋异常暖海温范围扩大，反气旋发展很强，同时在东亚太平洋上空出现P—J波列，华南上空的西南风与来自北方的偏北风在长江中下游地区辐合，造成长江中下游夏季降水偏多。

英文摘要：

Using NOAA_ ERSST, NCEP/NCAR reanalysis data sets and rainfall data at 160 stations in China, the paper studies the coupling relationship of summer precipitation in the mid low valley of the Yangtze River and sea surface temperature （ hereinafter referred to as ＂SST＂） in the northwest Pacific by means of a variety of statistical methods. Singular value decomposition （SVD） and correlation analyses show that summer precipitation in the mid-low valley of the Yangtze River is closely related with SST in the northwest Pacific, which primarily reflects inter-decadal variability, and not obviously related with other areas; Multivariate empirical orthogonal function （MV-EOF） analysis results prove that there exists significant coupling mode between summer precipitation in the mid-low valley of the Yangtze River, 850hPa wind over the East Asia-Pacific region and SST in the northwest Pacific, which means that when the summer precipitation in the mid-low valley of the Yangtze River is richer, there are anti-cyclone, cyclone, anti-cyclone anomalous wave （EAP teleconnection or P-J wave） from the south to the north over the East Asia-Pacific, and the East Asian summer monsoon is weaker. Season-reliant MV-EOF （SRMV-EOF） analysis shows that the coupling mode of summer precipitation in the mid-low valley of the Yangtze River and SST in the northwest Pacific is closely related with the pre-ENSO. In pre-autumn, ENSO signal comes forth in the eastern Pacific, and becomes mature in wintertime; meanwhile there is an anomalous anti-cyclone forming over the northwest Pacific, which lies in the east region to the Philippines. In spring, the ENSO is weakening, and there emerge warming SST anomalies in the northwest Pacific, which enhances the anti-cyclone. In summer, the ENSO signal disappears, the warming SST anomalies expand in the northwest Pacific and the anti-cyclone develops very strong. Meanwhile P-J teleconnection wave lies over the East Asia-Pacific, the southwest wind over the South China and the northerl