不同季节印度洋Walker环流年代际变化的海温驱动因素研究  

Study on Sea Surface Temperature Driving Factors of Decadal Variations of Indian Ocean Walker Circulation in Different Seasons

作　　者：颜博琼 郑小童 王浩 韩子文 张晏铭 Yan Boqiong;Zheng Xiaotong;Wang Hao;Han Ziwen;Zhang Yanming(The Key Laboratory of Physical Oceanography,Ministry of Education,Ocean University of China,Qingdao 266100,China;College of Oceanic and Atmospheric Science,Ocean University of China,Qingdao 266100,China)

机构地区：[1]中国海洋大学物理海洋教育部重点实验室,山东青岛266100 [2]中国海洋大学海洋与大气学院,山东青岛266100

出　　处：《中国海洋大学学报（自然科学版）》2024年第11期34-41,共8页Periodical of Ocean University of China

基　　金：国家自然科学基金项目(41975092)资助。

摘　　要：基于观测资料,本文研究了1900—2015年北半球不同季节影响印度洋沃克(Walker)环流年代际变化的关键海温异常和物理过程,发现在北半球冬季,热带东太平洋海温与热带北大西洋海温均对印度洋Walker环流的年代际变化有影响;在北半球夏季,印度洋Walker环流的年代际变化仅与热带北大西洋海温相关。进一步研究发现,冬季与夏季影响印度洋Walker环流年代际变化的物理机制存在差异。在冬季,太平洋Walker环流与印度洋Walker环流紧密耦合,热带东太平洋海温负异常以及热带北大西洋海温正异常会通过调制大气对流异常,进而增强太平洋Walker环流,并通过跨海盆的“齿轮”效应加强印度洋Walker环流;而在夏季,太平洋Walker环流与印度洋Walker环流的耦合关系消失,取而代之的是热带北大西洋海温正异常通过加强其上空以及北非的对流活动,激发大气开尔文(Kelvin)波而削弱印度洋Walker环流。值得注意的是,冬季和夏季热带北大西洋都对印度洋Walker环流有影响,但效应刚好相反:冬季热带北大西洋增暖有利于印度洋Walker环流的增强,而夏季热带北大西洋增暖使印度洋Walker环流减弱。本文的研究结果为气候长期变化预测提供了理论参考。Based on observational datasets,this study investigates the primary sea surface temperature(SST)anomalies and related physical processes that influence the decadal variation of Indian Ocean Walker Circulation(IOWC)in the Northern Hemisphere during different seasons during 1900—2015.In the boreal winter,the decadal variation of IOWC is mainly influenced by the SST in the eastern tropical Pacific and the tropical North Atlantic,whereas in the boreal summer,the decadal variation of IOWC is only associated with the tropical North Atlantic SST.Further investigation shows that the physical mechanisms on the decadal variations of IOWC are distinct in boreal winter and summer.During the winter,the Pacific Walker circulation(PWC)is closely coupled with the IOWC.The negative SST anomaly in the eastern tropical Pacific and the positive SST anomaly in the tropical North Atlantic can strengthen the PWC by modulating the atmospheric convection.Then the IOWC can be strengthened by the Indo-Pacific gear effect.During the summer,however,the coupling relationship between the PWC and the IOWC disappears,and the positive SST anomaly in the tropical North Atlantic can strengthen the local convection,further exciting atmospheric Kelvin wave to weaken the IOWC.It is worth noting that the tropical North Atlantic SST has an effect on IOWC both in winter and summer,but the effect is reversed:the warming of the tropical North Atlantic SST in winter is conducive to the strengthening of the IOWC,while the warming of the tropical North Atlantic SST in summer is conducive to the weakening of the IOWC.

关 键 词：印度洋Walker环流 太平洋Walker环流 年代际变化 热带北大西洋 热带太平洋 

分 类 号：P467[天文地球—大气科学及气象学]