中文摘要：

利用NCEP提供的大气再分析资料和云南122站降水资料分析了ENSO发展和衰减阶段对云南夏季降水异常的影响。结果发现：云南夏季降水异常分布对ENSO发展和衰减阶段的响应存在明显差异。处在发展阶段的El Nio事件会导致云南夏季大部分区域降水偏少;处在衰减阶段的El Nio事件会导致云南夏季降水呈现东少西多的分布;处在发展阶段的La Nia事件发会造成云南夏季大部分区域降水偏多,并且云南夏季降水异常对该阶段的响应最明显;处在衰减阶段的La Nia事件会造成云南夏季大部分区域降水偏少。通过合成分析发现：ENSO的发展和衰减阶段对夏季低纬度大气环流的影响存在显著差异,特别是对副热带高压和夏季风强弱的影响显著不同,从而导致云南夏季降水异常。值得一提的是,La Nia事件的发展阶段可作为影响云南夏季降水的一个强信号因子,应在短期气候预测中加以考虑。

英文摘要：

Based on the atmospheric data from NCEP reanalysis and precipitation data of 122 stations in Yunnan province,the influence of developing stage and decaying stage of ENSO events on the summer precipitation in the province is studied.The results show that the response of Yunnan summer precipitation to ENSO in the developing stage is very different from that of the decaying stage.During the developing stage of El Nio,most regions of Yunnan have less-than-normal summer precipitation,while in the decaying stage of El Nio,the summer precipitation is more than normal in the west of Yunnan and less than normal in the east.As for La Nia,during its developing stage,most regions of Yunnan have more-than-normal precipitation and the response of Yunnan summer precipitation to ENSO is the strongest.In the decaying stage of La Nia,the response of Yunnan summer precipitation to ENSO is weaker than that in the developing phase and the summer precipitation in most areas of Yunnan is less than normal.From composite analysis of atmospheric circulation,it is found that there is a significant difference in low-latitude circulation during the developing and decaying of ENSO,especially with regard to the impact on the subtropical high pressure and summer monsoon.The developing stage of the La Nia event is a strong influence signal for the summer precipitation of Yunnan,which can be used for short-term climate outlook in Yunnan province.