NUMERICAL SIMULATION OF LAG INFLUENCE OF ENSO ON EAST-ASIAN MONSOON

(整期优先)网络出版时间:2001-01-11
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Byprescribingseasurfacetemperatureanomalies(SSTAs)overeasternequatorialPacificinJanuary-March,thelaginfluenceofENSO(ElNinoandLaNina)onmonsoonoverEastAsiahasbeenstudied.Theresultssuggestthat,duetotheexcitationofatmosphericlow-frequencyoscillationbytheSSTA,ENSOhassignificantlaginfluenceonthemonsoonoverEastAsia.DuringthesummerafterElNino,thesubtropicalhighoverwesternPacificisintensifiedandshowsthenorthwardandwestwarddisplacement,meanwhile,therainfalloverEastChinaisbelownormal,especiallyinNorthChina;duringthewinterafterElNino,boththeAsiantroughandthewintermonsoonoverEastAsiaarestrengthened.DuringthesummerafterLaNina,theanomaloussubtropicalhighprevailsoverthelowerreachesofYangtze(Changjiang)River,therainfallbetweenYangtzeandHuaiheRiversisbelownormal;duringthewinterafterLaNina,boththeAsiantroughandthewintermonsoonoverEastAsiaareweaker.ComparedwithLaNina,theeffectofElNinoisstronger,butitisnotalwaysoppositetotheoneofLaNina.