The Coordinat...g Late Summer_Yitong LIN.pdf

The Coordinated Influence of Indian Ocean Sea Surface Temperatureand Arctic Sea Ice on Anomalous Northeast China Cold VortexActivities with Different Paths during Late SummerYitong LIN1,2,Yihe FANG*1,2,Chunyu ZHAO1,2,Zhiqiang GONG3,4,Siqi YANG5,and Yiqiu YU1,21Regional Climate Center of Shenyang,Liaoning Provincial Meteorological Administration,Shenyang 110016,China2Key Opening Laboratory for Northeast China Cold Vortex Research,China Meteorological Administration,Shenyang 110016,China3College of Physics and Electronic Engineering,Changshu Institute of Technology,Changshu 215500,China4Laboratory for Climate Studies,National Climate Research Center,China Meteorological Administration,Beijing 100081,China5Inner Mongolia Climate Center,Hohhot 010051,China(Received 27 December 2021;revised 6 April 2022;accepted 11 May 2022)ABSTRACTThe Northeast China cold vortex(NCCV)during late summer(from July to August)is identified and classified intothree types in terms of its movement path using machine learning.The relationships of the three types of NCCV intensitywith atmospheric circulations in late summer,the sea surface temperature(SST),and Arctic sea ice concentration(SIC)inthe preceding months,are analyzed.The sensitivity tests by the Community Atmosphere Model version 5.3(CAM5.3)areused to verify the statistical results.The results show that the coordination pattern of East Asia-Pacific(EAP)and LakeBaikal high pressure forced by SST anomalies in the North Indian Ocean dipole mode(NIOD)during the preceding Apriland SIC anomalies in the Nansen Basin during the preceding June results in an intensity anomaly for the first type ofNCCV.While the pattern of high pressure over the Urals and Okhotsk Sea and low pressure over Lake Baikal during latesummerwhich is forced by SST anomalies in the South Indian Ocean dipole mode(SIOD)in the preceding June and SICanomalies in the Barents Sea in the preceding Aprilcauses the intensity anomaly of the second type.The third type isatypical and is not analyzed in detail.Sensitivity tests,jointly forced by the SST and SIC in the preceding period,can wellreproduce the observations.In contrast,the results forced separately by the SST and SIC are poor,indicating that theNCCV during late summer is likely influenced by the coordinated effects of both SST and SIC in the preceding months.Key words:machine learning method,Northeast China cold vortex,path classification,Indian Ocean sea surfacetemperature,Arctic sea ice,model sensitivity testCitation:Lin,Y.T.,Y.H.Fang,C.Y.Zhao,Z.Q.Gong,S.Q.Yang,and Y.Q.Yu,2023:The coordinated influence ofIndian Ocean sea surface temperature and Arctic sea ice on anomalous Northeast China cold vortex activities with differentpaths during late summer.Adv.Atmos.Sci.,40(1),6277,https:/doi.org/10.1007/s00376-022-1415-9.Article Highlights:The NCCV during late summer is identified and categorized into three types based on their movement paths by amachine learning method.The NCCV is related to the coordinated influence of Indian Ocean sea surface temperature and Arctic sea ice in thepreceding months.1.IntroductionAs an important part of the atmospheric circulations inthe middle-and high-latitudes of the Northern Hemisphere,the Northeast China cold vortex(NCCV)has an importantinfluence on the persistence and adjustment of atmosphericcirculation anomalies in Northeast China(NEC)and in EastAsia.This pattern can occur all year round,with the highestfrequency of occurrence in the spring and summer(Sun et*Corresponding author:Yihe FANGEmail:ADVANCES IN ATMOSPHERIC SCIENCES,VOL.40,JANUARY 2023,6277 Original Paper Institute of Atmospheric Physics/Chinese Academy of Sciences,and Science Press and Springer-Verlag GmbH Germany,part of Springer Nature 2023al.,2000;Huang and Li,2020).The frequent NCCV activitiesare the primary cause of the meteorological disasters in theNEC(i.e.,rainstorms,short-term heavy precipitation,andlow-temperature damage),which have significant impactson agricultural production,transportation,and peoples lives(Sun et al.,2002).Therefore,it is very important to diagnoseand accurately predict the NCCV anomaly.Previous research mainly included the objective identifi-cation and climatological characteristics of the NCCV andthe causes of the NCCV anomaly.In terms of climatologicalcharacteristics,many statistical analyses have been conductedon the occurrence frequency,duration,change trend,period,and spatial distribution of the cold vortex in previous studies(Sun,1997;Liang et al.,2009;Hu et al.,2011;Xie andBueh,2012;Liu et al.,2015).As for the cause of the NCCVanomaly,some studies have been performed from the perspec-tive of atmospheric circulation factors(Liu et al.,2002;Heet al.,2006;Miao et al.,2006;Xie and Bueh,2012).Lian etal.(2010)analyzed the relationship between NCCV activityin early summer and the atmospheric circulations in the North-ern Hemisphere and pointed out that anomalous NCCV activ-ity in the early summer is related to the persistent circulatio