中文摘要：

根据ECMWF提供的1961-2002年月平均大气环流再分析资料、NOAA提供的海表温度资料和中国低纬高原的5月降水资料，应用扩展奇异值分析（ESVD）方法研究了中国低纬高原区5月降水、中国低纬高原相邻区域的水汽通量及其散度与全球海表温度场年际变化之间的关系，并通过合成分析对ESVD的分析结果进行验证。统计诊断的结果表明，中国低纬高原区5月降水、中国低纬高原及其相邻区域5月水汽通量及其散度与1—5月的海温异常场之间都具有很好的相关性。海表温度异常型造成中国低纬高原区5月降水异常的物理过程为：当前期1月一同期5月印度洋、西太平洋和东太平洋的海表温度距平呈“-、＋、-”（“＋、-、＋”）的纬向异常三极模或负位相的ENSO“Modoki”异常分布时，中心位于孟加拉湾的异常气旋式环流将孟加拉湾的异常偏多（少）水汽输送至中国低纬高原区，且中国低纬高原区处于水汽的异常辐合（辐散）区和大气环流的异常上升（下沉）区，相应的5月降水偏多（少）。由于1—5月海表温度异常型具有很好的持续性，是导致中国低纬高原5月降水异常的关键因素。因此，前期海表温度异常可以作为影响中国低纬高原5月降水的一个强信号因子，可在短期气候预测中加以应用。

英文摘要：

Making use of reanalysis data provided by ECMWF, sea surface temperature data provided by NOAA, and precipitation data over low-latitude plateaus of China in May, we analyzed the relationship between the precipitation over the low-latitude plateaus in May, vapor flux with its divergence and the global SST anomaly（SSTA）by using extended singular value decomposition（ESVD）. The results of statistical diagnosis and numerical simulation show that there is significant correlation between the precipitation over the plateaus and vapor flux with its divergence in May and the SSTA from January to May. A conceptual climate model for the SSTA influence on the precipitation of this region in May can be proposed as follows. When the tropical SSTA presents a tripole mode of ＂-, ＋, -＂ from the Indian Ocean to the eastern Pacific or the negative phase of ENSO＂Modoki＂ pattern, more water vapor is transported to the plateaus form the Bay of Bengal, exposing them to a vapor flux convergence anomaly area and eventually leading to increased precipitation over the plateaus in May. When SSTA is distributed in modes opposite to that above, the precipitation decreases in May. Because of the persistent nature of SSTA from January to May, its pattern is a key factor and a strong influence signal for the precipitation, which can be used for short-term climatic forecast.