The Role of Underlying Boundary Forcing in Shaping the Recent Decadal Change of Persistent Anomalous Activity over the Ural Mountains  

作　　者：Ting LEI Shuanglin LI 

机构地区：[1]Climate Change Research Center,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China [2]Beijing Meteorological Service Center,Beijing 100089,China [3]University of Chinese Academy of Sciences,Beijing 100049,China [4]Department of Atmospheric Science,China University of Geosciences,Wuhan 430074,China

出　　处：《Advances in Atmospheric Sciences》2024年第8期1496-1510,1661-1667,共22页大气科学进展（英文版）

基　　金：jointly supported by the National Key Research and Development Program of China (Grant No.2018YFA0606403);the National Natural Science Foundation of China (Grant No.41790473);the Beijing Natural Science Foundation (8234068)。

摘　　要：Observational analyses demonstrate that the Ural persistent positive height anomaly event(PAE) experienced a decadal increase around the year 2000, exhibiting a southward displacement afterward. These decadal variations are related to a large-scale circulation shift over the Eurasian Continent. The effects of underlying sea ice and sea surface temperature(SST) anomalies on the Ural PAE and the related atmospheric circulation were explored by Atmospheric Model Intercomparison Project(AMIP) experiments from the Coupled Model Intercomparison Project Phase 6 and by sensitivity experiments using the Atmospheric General Circulation Model(AGCM). The AMIP experiment results suggest that the underlying sea ice and SST anomalies play important roles. The individual contributions of sea ice loss in the Barents-Kara Seas and the SST anomalies linked to the phase transition of the Pacific Decadal Oscillation(PDO) and Atlantic Multidecadal Oscillation(AMO) are further investigated by AGCM sensitivity experiments isolating the respective forcings.The sea ice decline in Barents-Kara Seas triggers an atmospheric wave train over the Eurasian mid-to-high latitudes with positive anomalies over the Urals, favoring the occurrence of Ural PAEs. The shift in the PDO to its negative phase triggers a wave train propagating downstream from the North Pacific. One positive anomaly lobe of the wave train is located over the Ural Mountains and increases the PAE there. The negative-to-positive transition of the AMO phase since the late-1990s causes positive 500-h Pa height anomalies south of the Ural Mountains, which promote a southward shift of Ural PAE.

关 键 词：Ural persistent anomaly Pacific decadal oscillation Atlantic multidecadal oscillation sea ice loss in Barents-Kara Seas 

分 类 号：P467[天文地球—大气科学及气象学] P731.15