中文摘要：

利用1961—2010年NCEP再分析资料,分析了较有代表性的16个东亚夏季风指数,讨论了不同季风指数反映的环流及降水之间的异同,探讨了不同季风指数与东亚夏季风不同空间模态之间的可能关联。结果表明,东亚夏季风指数大致分为两类：1）第一类季风指数存在明显的年代际变化,反映了东亚夏季风强弱的整体一致型变化,与东亚夏季风环流第一模态具有很好的对应关系。高指数年,整个东亚区域夏季风活动整体偏强;贝加尔湖地区为深厚气旋性环流控制,副高位置略偏北;华北、东北地区降水显著偏多,长江流域及其以南降水偏少,降水异常型与我国夏季偶极型季风降水相似,这类指数对我国华北地区降水有较好的指示作用。2）第二类季风指数具有明显的年际变化特征,反映的是东亚夏季风强弱的南北反相变化,与东亚夏季风环流第二模态相对应。高指数年,我国东南地区夏季风偏弱,东北部夏季风偏强;西北太平洋为深厚的气旋性距平环流控制,副高偏北,该分布型与东亚—太平洋（EAP）遥相关十分相似;我国东北、内蒙古地区,华南地区降水增多,长江流域降水显著减少,降水异常型与我国夏季三极型季风降水异常型相似,这类指数对我国长江流域降水有较好的指示作用。

英文摘要：

Dozens of East Asian summer monsoon （EASM） indices have been proposed to represent the main features of anomalous summer monsoon activity based on different physical consideration.In this study,sixteen representa tive EASM indices were calculated based on the NCEP/NCAR reanalysis data （1961-2010） and detailed comparison has been performed to detect the differences among the EASM indices.We also explored the basic physical features of various EASM indices by comparing their differences in the related anomalous patterns of atmospheric general circulation and summer rainfall.The possible linkages of EASM indices with the predominant modes of EASM were also discussed.It is found that sixteen EASM indices can be generally classified into two categories （Category Ⅰ and Category Ⅱ）.Category Ⅰ mainly exhibits the decadal variation of EASM while Category Ⅱ is featured by strong interannual variability of EASM.Further analysis shows that：1） Category Ⅰ mainly reflects a consistent spatial variation of EASM and is closely linked to the first leading mode of EASM acquired by the extended empirical orthogonal function （EEOF） analysis of 850 hPa wind.Positive （negative） index of category shows intensified （weakened） southerly in the whole East Asian area,which is accompanied with anomalously intensified cyclonic （anti-cyclonic） circulation around the Lake Baikal and slightly northward （southward）western Pacific subtropical high （WPSH）.There are also corresponding anomalous 500 hPa geopotential height fields exhibiting a ＆quot;＋-＋＆quot; （＆quot;-＋-＆quot;） anomalous zonal pattern in the mid-high latitudes,originating from the western Europe,across the West Siberia plain,and extending to northeast Asia.Meanwhile,there is significantly increased （reduced） rainfall in North and Northeast China but reduced （increased） rainfall in the Yangtze River and its southern area,which consists of a typical dipole of monsoon rainfall anomalies.Category Ⅰ shows better d