Numerical Study on Microphysical Processes of Two Different Snowfall Cases in Northern China

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摘要 Inthispaper,twosnowfallcasesunderdifferentweatherconditionsinnorthernChinaaresimulatedbyusingthemesoscalemodelMM5.Two-waynestingstructureofdomainsisdesignedforeachcase.AmongtheexplicitschemesofMM5,theReisnergraupelschemeisselectedtodescribethemicrophysicalprocess.Thesimulatedsnow-bandsoftwocasesarebasicallyconsistentwithobservations.Thesimulatedresultsofmicrophysicalprocessesaremainlydiscussed.Thehydrometeorsandtheirsourcesandsinksunderdifferentweatherbackgroundsaredescribed.Thefeedbackeffectsofmicrophysicalprocessesonthethermalanddynamicprocessesarealsodiscussed.Methodthatoutputstheaccumulativesourcesandsinksperhourisusedtoanalyzethedistributioncharacteristicsofhydrometeorsduringthestrongestsnowfallperiod.Twosensitivitytests(calledheattestanddragtest)areconductedtoexaminetheeffectsofmicrophysicalpro-cessesoncloudproducedbythelatentheatanddragforce.Resultshaveshownthatthedistributionofparticleshasacloserelationwithtemperature.Thetem-peratureofBeijingsnowfallisunder0℃andthereexistvaporandsolidphaseparticles,whileLiaoningsnowfallhasvapor,liquid,andsolidphaseparticlesduetothewarmtemperature.Thedistributionoftheseparticlesisnotthesameatdifferentdevelopmentstages.Fromtheanalysesofthecharacteristicsofsourcesandsinks,itisfoundthatsnowismainlyproducedbythedepositionandaccretionwithice.Cloudwateriscrucialtograupel.Themeltingofice-phaseparticlesenhancestherainproduction.Theresultsofheattestsanddragtestsrevealthatthemicrophysicalprocesseshaveinteractedwiththedynamicandthermalprocesses.Latentheatreleaseofhydrometeorsfeedsbackpositivelyonsnowfallwhilethedragforcenot.Atlast,comparisonsofsimulatedresultshavebeendonebetweenthetwodifferentkindsofsnowfallcases.ThemicrophysicalprocessesofLiaoningsnowfallcaseismorecomplicatedthanthoseofBe
机构地区 不详
出处 《气象学报:英文版》 2007年4期
出版日期 2007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)
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