1980—2019年夏季东亚大槽减弱及其与北极海冰变化的关系  

Weakening of the East Asian Trough in Summer of 1980—2019 and Its Relationship with the Arctic Sea Ice Variability

作　　者：尹航 黄菲 陈峥[1,2] 王宏 Yin Hang;Huang Fei;Chen Zheng;Wang Hong(College of Oceanic and Atmospheric Sciences,Ocean University of China,Qingdao 266100,China;Physical Oceano-graphy Laboratory/Institute of Advanced Ocean Study,Ocean University of China,Qingdao 266100,China;Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266237,China)

机构地区：[1]中国海洋大学海洋与大气学院,山东青岛266100 [2]物理海洋教育部重点实验室和海洋高等研究院,山东青岛266100 [3]青岛海洋科学与技术试点国家实验室,山东青岛266237

出　　处：《中国海洋大学学报（自然科学版）》2022年第11期24-33,共10页Periodical of Ocean University of China

基　　金：国家重点研究发展计划项目(2019YFA0607004);国家自然科学基金项目(42075024,41906194,42006017);山东省自然科学基金重大基础研究项目(ZR2019ZD12)资助。

摘　　要：利用1979—2019年NECP/DOE(NCEP2)月平均500 hPa位势高度数据,基于各季节东亚大槽的频率分布特征,客观地确定了东亚大槽的槽区范围和东亚大槽强度指数。在此基础上,分析了夏季东亚大槽减弱与北极海冰变化的关系,结果表明:1980—2019年各季节东亚大槽强度均存在年代际减弱趋势,其中夏季减弱趋势最显著,可能与全球变暖导致的北极海冰快速融化有关。在年际尺度上,夏季东亚大槽强度减弱主要受前期夏秋季海冰的影响。当前一年夏季北极涛动为负位相时,受北极高压异常影响,海冰分布呈现格陵兰岛东部和加拿大群岛高密集度冰区海冰增加,欧亚-太平洋扇区季节性冰区海冰减少的偶极子型分布特点。在海冰反照率正反馈机制的作用下,秋季融冰区范围扩大,有利于极区的行星波1波异常信号上传至平流层。春季平流层的位势高度正异常信号在有利的行星Rossby波垂直传播条件下向南扩张并在东亚一侧下传,且一直持续到夏季,直接影响到东亚中纬度地区,使得东亚大槽减弱。Using the monthly mean 500 hPa geopotential height data of NCEP/DOE(NCEP 2)reanalysis dataset from 1979 to 2019,the region of the trough and the intensity index of the East Asia trough is determined objectively based on the frequency distribution characteristics of the East Asia trough in each season.On this basis,the relationship between the weakening of the summer East Asian trough and the Arctic sea ice is analyzed.The results show that there has been a decadal weakening trend in the intensity of the East Asian trough in all seasons from 1980 to 2019,and the weakening trend is the most significant in summer,which may be related to the rapid melting of Arctic sea ice caused by global warming.On the interannual scale,the intensity of summer East Asian trough mainly influenced by the sea ice in the early summer and autumn.When the Arctic Oscillation is in a negative phase in the summer of the year before weak summer East Asian trough,affected by the abnormal anticyclone,the sea ice distribution was characterized by a dipole pattern of increasing in eastern Greenland and the Canadian Islands,and decreasing in the Eurasia-Pacific sector.Due to the positive feedback mechanism of sea ice albedo,the extent of autumn melting area expands,which is conducive to the propagating of the anomalous signal of planetary wave 1 in the polar region.Under the favorable planetary Rossby wave vertical propagation condition,the positive anomalous geopotential height signal of the stratosphere expands southward and travels down the East Asian side in spring,and continues until summer,which directly affects the middle latitude area of East Asia and weakens the East Asia Trough.

关 键 词：东亚大槽 北极海冰 北极涛动 行星Rossby波 垂直传播 

分 类 号：P461[天文地球—大气科学及气象学]