UnderstandingtheDevelopmentofthe2018/19CentralPacificElNiñoChengyangGUAN1,XinWANG*2,3,4,andHaijunYANG51CollegeofOceanScienceandEngineering,ShandongUniversityofScienceandTechnology,Qingdao266590,China2StateKeyLaboratoryofTropicalOceanography,SouthChinaSeaInstituteofOceanology,ChineseAcademyofSciences,Guangzhou510301,China3SouthernMarineScienceandEngineeringGuangdongLaboratory(Guangzhou),Guangzhou511458,China4InnovationAcademyofSouthChinaSeaEcologyandEnvironmentalEngineering,ChineseAcademyofSciences,Guangzhou510301,China5DepartmentofAtmosphericandOceanicSciences,FudanUniversity,Shanghai200438,China(Received4November2021;revised17May2022;accepted18May2022)ABSTRACTAcentralPacific(CP)ElNiñoeventoccurredin2018/19.PreviousstudieshaveshownthatdifferentmechanismsareresponsiblefordifferentsubtypesofCPElNiñoevents(CP-IElNiñoandCP-IIElNiño).Bycomparingtheevolutionsofsurfacewinds,oceantemperatures,andheatbudgetsoftheCP-IElNiño,CP-IIElNiño,and2018/19ElNiño,itisillustratedthatthesubtropicalwesterlyanomaliesintheNorthPacific,whichledtoanomalousconvergenceofEkmanflowandsurfacewarminginthecentralequatorialPacific,playedanimportantroleinthe2018/19ElNiñoeventaswellasintheCP-IIElNiño.Althoughtheoff-equatorialforcingplayedavitalrole,itisfoundthattheequatorialforcingactedasadriving(damping)terminborealspring(summer)ofthe2018/19ElNiño.The2018/19ElNiñoprovidesatimelyandvividexamplethathelpsillustratetheproposedmechanismoftheCPElNiño,whichcouldbeleveragedtoimproveElNiñopredictability.Keywords:ElNiño,subtropicalPacific,westerlyanomalies,EkmantransportCitation:Guan,C.Y.,X.Wang,andH.J.Yang,2023:Understandingthedevelopmentofthe2018/19centralPacificElNiño.Adv.Atmos.Sci.,40(1),177−185,https://doi.org/10.1007/s00376-022-1410-1.ArticleHighlights:•The2018/19ElNiñowasaCPElNiño,andthewarmSSTanomaliesoriginatedinthesubtropicalNorthPacific.•EkmantransportcausedbythewesterlyanomaliesinthenorthernsubtropicalPacificwasvitalforthe2018/19ElNiñoaswellastheCP-IIElNiñoproposedinapreviou...
