STATISTIC CHARACTERISTICS OF MCSS OVER ASIA AND WESTERN PACIFIC REGION

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摘要 Mesoscaleconvectivesystems(MCSs)areseveredisaster-producingweathersystems.PreviousattemptsofMCScensusaremadebyexamininginfraredsatelliteimageriesartificially,withsubjectivityinvolvedintheprocessunavoidably.Thismethodisalsoinefficientandtime-consuming.ThedisadvantagesmakeitimpossibletodoMCScensusoverAsiaandwesternPacificregion(AWPR)withanextendedspanoftime,whichisnotfavorableforgainingadeeperinsightintothesesystems.Inthispaper,afire-newautomaticMCSidentification(AMI)methodisusedtocapturefourcategoriesofMCSswithdifferentsizesandshapesfromnumericalsatelliteinfrareddata.47,468MCSsareidentifiedoverAsiaandwesternPacificregionduringthewarmseason(MaytoOctober)from1995to2008.Basedonthisdatabase,MCScharacteristicssuchasshape,size,duration,velocity,geographicaldistribution,intermonthlyvariation,andlifecyclearestudied.ResultsindicatethatthenumberoflinearMCSsis2.5timesthatofcircularMCSs.Theformerisofalargersizewhilethelatterisofalongerduration.The500hPasteeringflowplaysanimportantroleintheMCSmovement.MCSstendtomovefasteraftertheyreachthemaximumextent.FourcategoriesofMCShavesimilarcharacteristicsofgeographicaldistributionandintermonthlyvariation.Basically,MCSsarezonallydistributed,withthreezonesweakeningfromsouthtonorth.TheintermonthlyvariationofMCSsisrelatedtotheseasonaladjustmentofthelarge-scalecirculation.AstotheMCSsoverChina,theyhavedifferentlifecyclecharacteristicsoverdifferentareas.MCSsoverplateausandhillareas,withonlyonepeakintheirlifecyclecurves,tendtoformintheafternoon,matureatnightfall,anddissipateatnight.Ontheotherhand,MCSsoverplains,whichhaveseveralpeaksintheirlifecyclecurves,mayformeitherintheafternoonoratnight,whereasMCSsovertheoceanstendtoformatmidnight.Affectedbythesea-landbreezecirculation,MCSsoverc
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出版日期 2012年04月14日(中国期刊网平台首次上网日期,不代表论文的发表时间)