东亚高空西风急流与东亚-西太平洋夏季风降水异常关系的年代际变化  

Interdecadal changes in the relationship between East Asia-West Pacific summer monsoonal precipitation anomalies and East Asian upper-tropospheric westerly jet stream

作　　者：胡春迪 林立飞 杨崧 HU Chundi;LIN Lifei;YANG Song(School of Atmospheric Sciences&Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies,Sun Yat-sen University,Guangdong Zhuhai 519082,China;Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Guangdong Zhuhai 519082,China;Key Laboratory of Tropical Atmosphere-Ocean System,Ministry of Education,Sun Yat-sen University Guangdong Zhuhai 519082,China)

机构地区：[1]中山大学大气科学学院/广东省气候变化与自然灾害研究重点实验室,广东珠海519082 [2]南方海洋科学与工程广东省实验室(珠海),广东珠海519082 [3]中山大学热带大气—海洋系统科学教育部重点实验室,广东珠海519082

出　　处：《气象科学》2020年第5期661-668,共8页Journal of the Meteorological Sciences

基　　金：国家自然科学基金资助项目(41975077,41705050);广东省气候变化与自然灾害研究重点实验室项目(2020B1212060025)。

摘　　要：东亚副热带西风急流(East Asian Jet Stream,EAJS)的经向位移对东亚-西太平洋夏季风降水活动有着重要影响。利用前人定义的EAJS经向位移指数(East Asian Jet Stream Index,EAJSI),发现盛夏(7、8月)EAJSI的年际变率在1990s末期经历了一次显著的年代际变化。而且EAJSI与东亚-西太平洋盛夏降水之间的关系自1999年以来显著减弱。在1980-1998年盛夏,与EAJSI相关的东亚-西太平洋降水异常呈典型的三极型模态,而这种相关关系在1999-2017年盛夏期间几乎消失了。其可能的原因是由于大尺度的大气-海洋环境年代差异,使得东亚-太平洋型/日本-太平洋型(East Asia-Pacific/Pacific-Japan,EAP/PJ)低频遥相关波列在1990s末期之后明显减弱和东移。这导致了盛夏EAJS经向位移的幅度显著减弱,进而引起EAJSI和东亚-西太平洋夏季风降水异常之间的关系转变。Meridional displacement of the East Asian Subtropical Westerly Jet Stream(EAJS)plays an important role in the East Asia-West Pacific(EA-WP)summer monsoon/precipitation activity.By using the EAJS-meridional displacement index(EAJSI),it is found that the interannual variability of EAJSI during mid-summer(July-August)has experienced a notable interdecadal change in the late-1990s.Besides,the relationship between EAJSI and EA-WP precipitation are correspondingly weakened significantly since 1999.Compared with the classical tripole mode of the EA-WP precipitation anomalies linked to EAJSI during mid-summer for 1980-1998,such relationship has almost disappeared during 1999-2017.Further analysis suggests that the possible reason is that the EAP/PJ(East Asia-Pacific/Pacific-Japan)teleconnection wave-train has significantly weakened and shifted eastward after the late-1990s due mainly to the interdecadal differences of the large-scale atmospheric-oceanic environments.As a result,the amplitude of the meridional displacement of EAJS has significantly weakened,leading to the shifting correspondence between EAJSI and summer monsoonal precipitation anomalies over the EA-WP.

关 键 词：东亚—西太平洋 副热带西风急流 盛夏降水异常 年代变化 

分 类 号：P444[天文地球—大气科学及气象学]