东亚夏季降水的年代际变化是汛期降水预测的背景条件，也是大气科学研究的热点和难点问题。我国地处东亚季风区，夏季气候和降水变化受东亚夏季风系统影响明显，深入开展我国夏季降水年代际突变问题研究对提高东亚夏季气候预测水平具有重要意义。.本项目以21世纪初期我国东部夏季降水年代际突变特征与机理为研究目标，使用观测资料统计检验、环境场变量诊断分析以及敏感性数值模拟试验等方法，提取并分析此次降水年代际突变的多要素特征，揭示热带印度洋-太平洋SSTA及热带海温梯度等海洋热状况影响东亚大尺度环流和我国东部降水年代际突变的过程机理，定量评估不同海域海表面温度异常（SSTA）及海温梯度变化对此次突变的相对贡献和协同影响。通过开展项目研究，深化对我国东部夏季降水长时间尺度变化规律的认识，为提高汛期降水定量化预报预测水平提供科学依据。

The interdecadal variation of summer rainfall in east Asia is the background condition of flood season rainfall prediction, and it is also the hot and difficult issue in field of atmospheric science research. China is located in the east Asian monsoon region, and the variation of summer climate and precipitation is tremendously affected by the east Asian summer monsoon system. Therefore, it is of great significance to investigate the interdecadal abrupt change of summer rainfall in eastern China to improve the accuracy of long-term prediction of east Asian summer climate..This project focuses on construction, mechanism and cause of the interdecadal abrupt change in the boreal summer rainfall in east China occurring in the early twenty-first century. Based on the statistical analyses, diagnosis methods and numerical simulations, the comprehensive features of rainfall interdecadal changes in the different regions over East China will be analyzed, and the influences and mechanisms of the tropical Pacific-Indian Ocean SSTA and the associated SST gradient on the interdecadal changes in atmospheric circulation and rainfall will be investigated. The relative contribution and synergistic effect of SSTA and SST gradient changes in different sea areas on the interdecadal change will be evaluated. This project might be beneficial for the improvement of summer rainfall forecast and seasonal prediction in East China in the future.