夏冬季热带太平洋、印度洋海表温度年际异常的年代际变化

用Nino 3指数、印度洋单极指数、偶极子指数描述热带太平洋、印度洋海表温度 (SST)的年际异常 ,季节分析表明 :冬季Nino3区与热带印度洋海表温度距平 (SSTA)相互关系表现为单极 ,且 1976年以后两者的相互关系减弱 ,其可能原因 :一是冬季是ENSO(厄尔尼诺 )事件的盛期 ;二是冬季西太平洋暖水区东移 ,造成两洋的垂直纬向环流耦合减弱。夏季两者相互关系表现为偶极 ,1976年以后两者的相互关系加强 ,其可能原因 ,一是夏季是偶极子盛期 ,ENSO事件的发展期 ;二是夏季西太平洋暖水区虽然东移 ,但暖水区位置偏北 ,且东南印度洋的上升支强度增大 ,造成两洋的纬向环流耦合更强烈

Inter-decadal Change of Sea Surface Temperature and Its Interaction Between Tropical Pacific and Indian Ocean in Summer and Winter

By using Nino3 index,Dipole index and Unipole index, the inter-decadal variations in the relationship of sea surface temperature between the inter-annual anomalies of the tropical Pacific and Indian Ocean in winter and summer are examined. Results indicate that in winter the signal of ENSO is same in whole Indian Ocean, but decreased after 1976, the possible reasons are: first, ENSO is thriving in winter; second, is after 1976, the warmer center of the Pacific moved eastward ,therefore the two vertical zonal circulation coupled weaken. In summer the signal of ENSO is different in west Indian Ocean and east Indian Ocean, but enhanced after 1976, the possible reasons that the first is Unipole is thriving in summer, and that though after 1976 the warmer center of the Pacific moved eastward, but the warmer center moved northward too, and the intensity of the updraft of the monsoon circulation over the tropical Indian Ocean is strengthen ,therefore the two vertical zonal circulation coupled enhanced.