影响东亚冬季气温的大气遥相关型的年代际变化特征  

Interdecadal Variations in Atmospheric Teleconnection Patterns Affecting Winter Temperature over East Asia

作　　者：罗敬 施宁[1] 周波涛[1] 张东东 LUO Jing;SHI Ning;ZHOU Botao;ZHANG Dongdong(Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)/Key Laboratory of Meteorological Disaster,Ministry of Education(KLME)/Joint International Research Laboratory of Climate and Environment Change(ILCEC),Nanjing University of Information Science&Technology,Nanjing 210044;Guizhou Meteorological Observatory,Guiyang 550002)

机构地区：[1]南京信息工程大学气象灾害预报预警与评估协同创新中心/气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室,南京210044 [2]贵州省气象台,贵阳550002

出　　处：《大气科学》2024年第6期2247-2263,共17页Chinese Journal of Atmospheric Sciences

基　　金：国家自然科学基金项目42025502、41975063;江苏省青蓝工程。

摘　　要：基于1958/1959~2020/2021年冬季NCEP、JRA-55、ERA5三种再分析资料,本文在扣除线性趋势后,采用EOF、REOF、相关与偏回归等方法,揭示出影响东亚冬季气温主要模态的大气遥相关型,并对这些遥相关型的年代际变化特征及影响进行了分析。结果表明:与东亚冬季气温第一主成分(PC1)最相关的是斯堪的纳维亚遥相关型(SCA),与第二主成分(PC2)最相关的是东大西洋遥相关型(EA)。在年代际时间尺度上,SCA、EA型与东亚冬季气温PC1和PC2也存在着较好的对应关系。SCA型在1970s末期和2000s初期发生的位相变化对应着东亚冬季气温PC1的位相变化;EA型在1980s初期、1990s末期和2010s初期发生的位相变化大致对应着东亚冬季气温PC2的位相变化。但需指出的是,SCA指数与东亚冬季气温PC1之间的相关系数(R1)以及EA指数与东亚冬季气温PC2之间的相关系数(R2)却呈现出不同于SCA和EA自身位相的年代际变化特征。R1在1980s中期以前呈减弱特征,此后数值明显增大,表明SCA型对东亚冬季气温影响更显著。R1的年代际强弱变化与SCA型中位于俄罗斯西部的环流异常是否向东扩展有关,AMO在其中起着重要的调节作用。至于R2,它的年代际强弱变化也较明显,其大值时段主要为1970s、1980s和2000年后,这与EA型是否在东亚地区形成局地的经向偶极型环流异常有关,而与海温或海冰异常的关系并不显著。Utilizing the NCEP,JRA-55,and ERA5 reanalysis data sets spanning from the boreal winters from 1958/1959 to 2020/2021,this study investigates atmospheric teleconnection patterns that affect winter air temperature variations in East Asia.After removing the linear trend,we explore the primary modes of these temperature variations and their interdecadal variations using conventional statistical methods,e.g.,Empirical Orthogonal Function(EOF),Rotated Empirical Orthogonal Function(REOF),correlation,and partial regression analyses.The results show that the Scandinavian teleconnection(SCA)and the East Atlantic(EA)teleconnection patterns significantly influence the first and second principal components(PC1 and PC2,respectively)of winter air temperature variability in East Asia.On interdecadal timescales,these patterns show consistent shifts.Specifically,changes in the SCA patterns during the late 1970s and early 2000s align well with shifts in PC1 of East Asian air temperatures.Similarly,the EA pattern’s phase shifts in the early 1980s,late 1990s,and early 2010s correspond to changes in PC2.Notably,the correlation coefficients between the SCA index and PC1(R1)and between the EA index and PC2(R2)reveal different decadal variations,diverging from those of the two teleconnections.Before the mid-1980s,R1 shows a decreasing trend,followed by a significant increase,indicating a strengthening influence of the SCA on East Asian air temperature.Such an interdecadal variation in R1 strength is related to circulation anomalies centered over western Russia associated with SCA,extending further eastward,possibly determined by the Atlantic Multidecadal Oscillation(AMO).There is also an evident decadal variation in R2 strength.R2 is strong only during the 1970s to 1980s and after the 2000s.This suggests that the EA’s influence on East Asian air temperatures relies on its ability to form a local meridional dipole circulation pattern rather than being directly related to sea surface temperature or sea ice concentration anomalies.

关 键 词：东亚冬季气温 大气遥相关型 斯堪的纳维亚遥相关型(SCA) 东大西洋遥相关型(EA) 年代际变化 

分 类 号：P466[天文地球—大气科学及气象学]