简介:Thispaperanalyzesthecharacteristicsofsupertyphoons(STYs)overthewesternNorthPacific(WNP)from1965to2005anddescribestheseasonalvariabilityofSTYactivity.TherelationbetweenSTYactivityandtheElNio-SouthernOscillation(ENSO)aswellasthepossiblereasonfortheinfluenceoftheENSOonSTYactivityarealsoinvestigated.Theresultsshowedthataboutonefifthofthetropicalcyclones(TCs)overtheWNPcouldreachtherankofSTY.MostSTYsappearedfromJulytoNovem-berwhiletherewasahighestratiobetweennumberofSTYsandtotalnumberofTCsinNovember.MostSTYsappearedeastofthePhilippineSea.InElNioyears,affectedbyseasurfacetemperature(SST),monsoontroughandweakverticalwindshear,TCfor-mationlocationsshiftedeastwardandthereweremoreSTYsthaninLaNiayearswhentheaffectingfactorschanged.