中文摘要：

在西方的中国影响9月 降水的地区性的风索引用 700 hPa u 和 1961～2006 .There 的 NCAR/NCEP 分析数据的 v 部件被定义是三地区性的风地 indices:southwest ，东南，和北方，并且这些索引反映在这些索引之间的东方亚洲 monsoon.The 关系的变化被学习，并且结果证明他们不仅有结束关系，而且有 independence.Moreover ，在风 indic 之间有一种明显的关系

英文摘要：

The regional wind index influencing September precipitation in western China has been defined using the 700 hPa u and v components of NCAR/NCEP reanalysis data of 1961 to 2006. There are three regional wind field indices： southwest, southeast, and north, and these indices reflect the change of East Asian monsoon. The relationship between the indices was studied, and results show that they not only have a close relationship, but also have independence. Moreover, there is an obvious relationship between the wind indices and the autumn in particular the September precipitation in western China. The effect of wind indices on rain occurrence is most different： the influenced area of the southwest wind index is larger than that of the southeast wind index, and the southwest wind index is a controlling factor on autumn precipitation in western China. The weakening of southwest wind is the main cause resulting in reduction of autumn precipitation on the east side of the Tibetan Plateau.