Interdecadal change and projection of the relationship between spring Arctic Oscillation and summer precipitation in the Yangtze River valley in CMIP6 models  

作　　者：Weikai Jia Botao Zhou Ziyi Song 

机构地区：[1]Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/Key Laboratory of Meteorological Disaster,Ministry of Education/Joint International Research Laboratory of Climate and Environment Change,Nanjing University of Information Science and Technology,Nanjing,China

出　　处：《Atmospheric and Oceanic Science Letters》2024年第4期15-22,共8页大气和海洋科学快报（英文版）

基　　金：supported by the National Natural Science Foundation of China [grant number 42025502]。

摘　　要：评估了20个CMIP6模式对春季北极涛动(AO)与长江流域夏季降水(YRP)关系的模拟能力.结果表明, 4个模式(ACCESS-ESM1-5, CMC-CM2-SR5, MRI-ESM2-0, NorESM2-LM))能合理模拟出1990年代后期AO-YRP关系的减弱. 1980-1998年,当春季AO位于正位相时,夏季东亚急流北移,长江流域为异常下沉运动,同时西太平洋副热带高压减弱,减少向长江流域的水汽输送,结果导致降水减少. 1999-2014年,上述大气环流与春季AO的联系不显著,从而减弱AO-YRP的关系.利用这四个模式进一步预估了RCP4.5情景下2015-2100年期间AO-YRP的关系.两者在2015-2040年为显著负相关关系,随后再次减弱.This paper assesses the performance of 20 CMIP6 models in simulating the relationship between spring Arctic Oscillation(AO)and summer precipitation in the Yangtze River valley(YRP)over the period 1980-2014.Their relationship during 2015-2100 under SSP2-4.5 is also projected.The assessment indicates that four models(ACCESS-ESM1-5,CMC-CM2-SR5,MRI-ESM2-0,and NorESM2-LM)can reasonably simulate the observed interdecadal weakening of the AO-YRP connection in the late 1990s.During 1980-1998,corresponding to the positive phase of spring AO,the East Asian jet(EAJ)shifts northward in summer,favoring descending anomalies over the Yangtze River valley.Meanwhile,the western Pacific subtropical high is weaker than normal and anomalous northeasterlies prevail in the lower troposphere of the Yangtze River valley,reducing the water vapor transport to the target region.These situations are unfavorable for the occurrence of precipitation,consequently resulting in a decrease in summer YRP.During 1999-2014,however,the association of the above atmospheric circulations with spring AO becomes insignificant,thus diluting the AO-YRP connection.The ensemble of the four models projects that the significant out-of-phase relationship between spring AO and summer YRP will recover in the near term(2015-2040)and weaken again afterwards.Such projected relationships are supported by the changes in the linkage of summer atmospheric circulations to spring AO.

关 键 词：北极涛动 降水 长江流域 年代际变化 CMIP6 

分 类 号：P941.62[天文地球—自然地理学] P467