简介：ThetropicalPacifichasbeguntoexperienceanewtypeofElNio,whichhasoccurredparticularlyfrequentlyduringthelastdecade,referredtoasthecentralPacific(CP)ElNio.Variouscoupledmodelswithdifferentdegreesofcomplexityhavebeenusedtomakereal-timeElNiopredictions,buthighuncertaintystillexistsintheirforecasts.ItremainsunknownastohowmuchofthisuncertaintyisspecificallyrelatedtothenewCP-typeElNioandhowmuchiscommontoboththistypeandtheconventionalEasternPacific(EP)-typeElNio.Inthisstudy,thedeterministicperformanceofanElNio–SouthernOscillation(ENSO)ensemblepredictionsystemisexaminedforthetwotypesofElNio.EnsemblehindcastsarerunforthenineEPElNioeventsandtwelveCPElNioeventsthathaveoccurredsince1950.Theresultsshowthat(1)theskillscoresfortheEPeventsaresignificantlybetterthanthosefortheCPevents,atallleadtimes;(2)thesystematicforecastbiasescomemostlyfromthepredictionoftheCPevents;and(3)thesystematicerrorischaracterizedbyanoverlywarmeasternPacificduringthespringseason,indicatingastrongerspringpredictionbarrierfortheCPElNio.Furtherimprovementstocoupledatmosphere–oceanmodelsintermsofCPElNiopredictionshouldberecognizedasakeyandhigh-prioritytaskfortheclimatepredictioncommunity.