中文摘要：

利用1960-2010年湖南20个测站的降水资料,采用经验正交函数分解（EOF）等方法分析了湖南冬季降水的年代际变化特征及其影响因子。结果表明：1973-2009年湖南冬季降水经历了两次年代际突变,分别出现在1988和1998年。1973-1987年湖南冬季降水偏少,1988-1997年降水偏多,1998-2009年降水再次偏少。湖南降水的年代际变化与西伯利亚高压、北极涛动（AO）、东亚西风急流和欧亚遥相关型年代际变化的协同作用有关。西伯利亚高压偏弱、AO指数偏强、东亚西风急流偏弱以及欧亚遥相关型为负位相这些因子的共同作用导致1988-1997年期间湖南冬季降水偏多。而1973-1987年和1998-2009年,湖南冬季降水偏少时期,上述影响因子的变化则基本相反。

英文摘要：

Based on the monthly rain gauge data（ 1960-2010） from 20 stations in Hunan Province,the interdecadal change of winter precipitation over Hunan and its physical factors are investigated. The results indicate that there were two abrupt changes of winter precipitation,which appeared in 1988 and1998,respectively. The precipitation was less during the years of 1973-1987 and 1998-2009,while the precipitation was more during the years of 1988-1997. The interdecadal change of winter precipitation in Hunan was attributed to the collaborative variations of Siberian High,Arctic Oscillation,the East Asian jet stream and Eurasian teleconnection pattern. During the 1988-1997 period,the intensity of Siberian High and the East Asian jet stream was weaker,Arctic Oscillation index was higher,and the Eurasian teleconnection pattern was in the negative phase. The aforementioned factors worked cooperatively to induce more precipitation. During the periods of 1973-1987 and 1998-2009,these factors showed roughly opposite changes,resulting in less winter rainfall.