东亚夏季风降水年代际变异模态及其与太平洋年代际振荡的关系

利用全球陆地月平均降水资料、英国气象局哈德莱中心的月平均海表温度距平(SSTA)资料及NCEP/NCAR再分析大气环流资料,探讨东亚夏季风降水年代际变率及其与太平洋年代际振荡(PDO)的联系。研究指出:东亚夏季风降水年代际变异模态以及PDO均在1976年前后呈现显著的年代际转折,并且东亚夏季风降水与PDO在年代际尺度上具有较好的相关关系。PDO能够在对流层低层激发出与年代际东亚夏季风环流较为相似的大气环流异常特征,表明东亚夏季风环流的年代际变化可能受大气外强迫因子PDO在对流层低层的外源强迫作用影响,最终导致东亚夏季风降水发生年代际变化。

The Inter-decadal Mode of the Summer Monsoon Rainfall in East Asia and Its Association with Pacific Decadal Oscillation

The inter-decadal variation of summer monsoon rainfall in East Asia and its relationship with Pacific Decadal Oscillation(PDO)are investigated by using monthly precipitation reconstruction over global land,the monthly sea surface temperature anomaly(SSTA)of Hadley Center for Climate Prediction and Research,and the National Centers for Environmental Prediction/National Center for Atmospheric Research(NCEP/NCAR)reanalysis dataset.It is revealed that both the inter-decadal mode of the summer monsoon rainfall in East Asia and PDO occurred ap-parent inter-decadal shift around 1976.Moreover,there exists close relation between summer monsoon rainfall and PDO on inter-decadal time scale.PDO can generate anomalous atmospheric circulation in the low-level troposphere,which is homologous with the inter-decadal variability of summer monsoon circulation in East Asia.It suggests that the external forcing of PDO in lower troposphere possibly exerts influences on the inter-decadal variability of the East Asia summer monsoon circulation,and finally leads to the inter-decadal variability of the summer monsoon rainfall in East Asia.