How does the Indian Ocean subtropical dipole trigger the tropical Indian Ocean dipole via the Mascarene high?

作     者：FENG Junqiao HU Dunxin YU Lejiang 

作者机构：Institute of OceanologyChinese Academy of Sciences Key Laboratory of Ocean Circulation and WaveChinese Academy of Sciences Applied Hydrometeorological Research Institute Nanjing University of Information Science and Technology 

出 版 物：《Acta Oceanologica Sinica》 (海洋学报（英文版）)

年 卷 期：2014年第33卷第1期

页      面：64-76页

核心收录：

学科分类：07[理学] 070601[理学-气象学] 0706[理学-大气科学] 

基　　金：The National Natural Science Foundation of China under contract Nos 41106016 and 41330963 the National Basic Research Program(973 Program)of China under contract No.2012CB417403 

主　　题：Indian Ocean dipole Indian Ocean subtropical dipole Mascarene high 

摘      要：The variation in the Indian Ocean is investigated using Hadley center sea surface temperature（SST） data during the period 1958–*** the first empirical orthogonal function（EOF） modes of the SST anomalies（SSTA） in different domains represent the basin-wide warming and are closely related to the Pacific El Ni o– Southern Oscillation（ENSO） *** examination suggests that the impact of ENSO on the tropical Indian Ocean is stronger than that on the southern Indian *** second EOF modes in different domains show different *** shows a clear east-west SSTA dipole pattern in the tropical Indian Ocean（Indian Ocean dipole,IOD）,and a southwest-northeast SSTA dipole in the southern Indian Ocean（Indian Ocean subtropical dipole,IOSD）.It is further revealed that the IOSD is also the main structure of the second EOF mode on the whole basin-scale,in which the IOD pattern does not appear.A correlation analysis indicates that an IOSD event observed during the austral summer is highly correlated to the IOD event peaking about 9 months *** of the possible physical mechanisms underlying this highly significant statistical relationship is *** IOSD and the IOD can occur in sequence with the help of the Mascarene *** SSTA in the southwestern Indian Ocean persists for several seasons after the mature phase of the IOSD event,likely due to the positive wind–evaporation–SST feedback *** Mascarene high will be weakened or intensified by this SSTA,which can affect the atmosphere in the tropical region by *** pressure gradient between the Mascarene high and the monsoon trough in the tropical Indian Ocean increases（decreases）.Hence,an anticyclone（cyclone） circulation appears over the Arabian Sea-India *** easterly or westerly anomalies appear in the equatorial Indian Ocean,inducing the onset stage of the *** study shows that the SSTA associated with the IOSD can lead to the onset of IOD with the aid of atmosphe