南印度洋海温偶极子型振荡及其气候影响

印度洋海表温度（Sea Surface Temperature，简称SST）的方差分析和相关分析表明南印度洋也存在一个海温偶极子型振荡，并定义了一个南印度洋海表温度异常偶极子指数.夏、秋季（南半球冬、春）的南印度洋偶极子指数与后期热带500hPa和100hPa高度场异常有显著而持续的相关，在冬、春达到最大，并可以持续到次年夏、秋.前期夏、秋季节的南印度洋偶极模对次年我国大陆东部夏季降水异常有显著的影响，对应偶极子正位相，次年夏季印度洋、南海（东亚）夏季风偏弱；副高加强且南撤、西伸，南亚高压偏强且位置偏东，易形成我国长江流域降水偏多，华南降水偏少；负位相年反之.后期冬季西太平洋暖池是联系南印度洋偶极子与次年我国夏季降水异常关系的一条重要途径.南印度洋偶极子表现出了明显的独立于ENSO（El Nio Southern Oscillation，简称ENSO）的特征.

Dipole oscillation in the Southern Indian Ocean and its impacts on climate

Variance and correlation analysis of the Indian Ocean sea surface temperature (SST) indicates that a strong dipole oscillation occurs in the Southern Indian Ocean, and then a Southern Indian Ocean SST anomaly dipole index (SIODI) is defined. The index in summer and autumn has significant and sustained correlations with the following 500 hPa and 100 hPa geopotential height anomalies in the tropical regions, which are most significant in winter and next spring and can persist 10 months until next summer and autumn. The SIODI is closely related to the post summer rainfall anomalies in China. Corresponding to the positive phase of the SIODI, the West Pacific subtropical high extends westward and the Tibetan high is strong and extends eastward, Indian and South China Sea summer monsoons are weak, all of which lead to more/less rainfall in the Yangtze River basin/South China. The reverse occurs during a negative phase scenario. The West Pacific warm pool plays an important role in the relationship between the SIODI and the rainfall anomalies in China. The SIODI can be regarded as independent of ENSO (El Nio Southern Oscillation).