TheCoordinatedInfluenceofIndianOceanSeaSurfaceTemperatureandArcticSeaIceonAnomalousNortheastChinaColdVortexActivitieswithDifferentPathsduringLateSummerYitongLIN1,2,YiheFANG*1,2,ChunyuZHAO1,2,ZhiqiangGONG3,4,SiqiYANG5,andYiqiuYU1,21RegionalClimateCenterofShenyang,LiaoningProvincialMeteorologicalAdministration,Shenyang110016,China2KeyOpeningLaboratoryforNortheastChinaColdVortexResearch,ChinaMeteorologicalAdministration,Shenyang110016,China3CollegeofPhysicsandElectronicEngineering,ChangshuInstituteofTechnology,Changshu215500,China4LaboratoryforClimateStudies,NationalClimateResearchCenter,ChinaMeteorologicalAdministration,Beijing100081,China5InnerMongoliaClimateCenter,Hohhot010051,China(Received27December2021;revised6April2022;accepted11May2022)ABSTRACTTheNortheastChinacoldvortex(NCCV)duringlatesummer(fromJulytoAugust)isidentifiedandclassifiedintothreetypesintermsofitsmovementpathusingmachinelearning.TherelationshipsofthethreetypesofNCCVintensitywithatmosphericcirculationsinlatesummer,theseasurfacetemperature(SST),andArcticseaiceconcentration(SIC)intheprecedingmonths,areanalyzed.ThesensitivitytestsbytheCommunityAtmosphereModelversion5.3(CAM5.3)areusedtoverifythestatisticalresults.TheresultsshowthatthecoordinationpatternofEastAsia-Pacific(EAP)andLakeBaikalhighpressureforcedbySSTanomaliesintheNorthIndianOceandipolemode(NIOD)duringtheprecedingAprilandSICanomaliesintheNansenBasinduringtheprecedingJuneresultsinanintensityanomalyforthefirsttypeofNCCV.WhilethepatternofhighpressureovertheUralsandOkhotskSeaandlowpressureoverLakeBaikalduringlatesummer—whichisforcedbySSTanomaliesintheSouthIndianOceandipolemode(SIOD)intheprecedingJuneandSICanomaliesintheBarentsSeaintheprecedingApril—causestheintensityanomalyofthesecondtype.Thethirdtypeisatypicalandisnotanalyzedindetail.Sensitivitytests,jointlyforcedbytheSSTandSICintheprecedingperiod,canwellreproducetheobservations.Incontrast,theresultsforcedseparatelybytheSSTandSICarepoor,indicatingthattheNCCVduringlatesummerislikelyinfluenced...
