Inthisstudy,twopossiblepersistentanomaliesoftheMadden-JulianOscillationmode(MJO)arefoundinthesummerseason(persistentlyPacificactiveandIndianOceanactive),andanindexissettodefinetheintensityofthetwomodes.TheyareprovedtohavehighstatisticalcorrelationstothelaterENSOeventsintheautumnandwinterseasons:WhenpersistentanomalyofMJOhappensinthePacificOceaninsummer,ElNinoeventsareofteninducedduringtheautumnandwinterseasonsofthatyear.However,duringtheotherMJOmodewhenthesummerpersistentanomalyofMJOoccursintheIndianOcean,LaNinaeventsoftenfollowinstead.TheanalysisoftheatmosphericcirculationfieldindicatesthatpersistentanomalyofMJOcanprobablyaffecttheentireEquatorialPacificcirculation,andresultsinwindstressanomalies.Thewindstressanomaliescouldexcitewarmorcoldwatermasseswhichpropagateeastwardsatthesubsurfaceocean.TheaccumulationofwarmorcoldsubsurfacewaterintheEquatorialEasternPacificOceanmayeventuallyleadtotheformationofanENSO.
