简介:Inthepresentpaperitwillbeshownthat,bytakingthereferenceframemovingwiththevelocityoffluidattheinterlaceoftwosteadyparallelstreams,thelaminarboundarylayerflowinthetwofluidscanbedecoupledintotwoflows.Theseareexactlythesameasthelaminarboundarylayerflowsalongaflatplate.Andthat,byusingtheexistingexactsolutionofthelaminarboundarylayerequationfortheboundarylayerflowalongaflatplateandappropriateboundaryconditions.Anexactsolutionofthelaminarboundarylayerequationforthelaminarboundarylayerbetweentwoparallelstreamswithdifferentdensities,viscocitiesandvelocitiesisgivenelegantly.ForthecasesconsideredbyLock,theresultsobtainedbythepresentmethodarecomparedwithLock’snumericalcalculationsindetail.
简介:Theatmosphericgeneralcirculationmodelcoupledtothemixedlayeroceanmodelhasbeenusedtosimulatethechangesoftheglobalsoilmoisture.Comparingthesimulatedresultswithobservations,itisshownthatthemodelisca-pableofdoingsensitiveexperimentsaboutthecarbondioxidechange.The2×CO2/1×CO2comparisonshowsthattherearetheobviouschangesofthesoilmoistureintheglobalforfourseasons.Therearethewetsoilmoistureinthelowerlatitudesofbothhemispheresanddrysoilmoistureinthemid-dlelatitudesofbothhemispheresforfourseasons.Thedrysoilmoistureinsummerandwetinotherseasonsarefoundinthenorthernhigherlatitudes.TheanalysesofthephysicalfeedbacksresponsiblefortheCO2-inducedchangesofsoilmoistureshowthatthebud-getsofthesurfacewaterandheataretheimportantfactors.
简介:Inthispaper,takingitsturbulentexchangecoefficientasafunctionoftheLagrangiantimescaleandstandardvarianceoftheturbulenceinatmosphere,theatmosphericdispersionPDFmodelsareobtainedonthebasisofatmosphericdiffusionK-theory.Inthemodelthestatisticsofwindspeedaredirectlyusedasitsparametersinsteadofclassicdispersionparameters.Thebi-GaussianPDFisderivedinconvectiveboundarylayer(CBL),fromthestatisticsofverticalvelocityinbothofthedowndraftandupdraftregionsthatareinvestigatedtheoreticallyintheotherpartofthispaper.GivingthedrivenparametersoftheCBL(includingtheconvectivevelocityscalew*andthemixingdepthh_i)andthetime-averagedwindspeedatreleaselevel,thePDFmodelisabletosimulatethedistributionofconcentrationreleasedatanylevelsintheCBL.ThePDF’ssimulationsarefairlyconsistentwiththemeasurementsinCONDORSexperimentortheresultsbroughtoutbysomenumericalsimulations.
简介:ADopplersodarsystemcontrolledbymicrocomputerisdescribedinthispaper.Thesodarwasusedtodetecttheverticaldistributionofwindandtemperaturestratificationintheatmosphericboundarylayer.Thedetectingresultsshowthatatnighttheverticaldistributionofwindisverycomplicated,whichcanappearasastructureoftwoorthreelayers.Innocturnalatmosphericboundarylayersometimesthereexistsverythinlayerinmulti-layerinversionanditcanberetainedforalongtime.
简介:ThebiomassesoffishesatthebottomlayeroftheBohaiSeaareextimatedbyanalysingthedataonsamples(447hauls,morethan0.2millioninnumberor20tinweightoffishes)collectedmonthlybyourinstitutefromApril,1982toMay,1983byapairofbottomtrawlsthroughtheBohaiSea.Theexploitationproblemsarealsodiscussedinthispaper.
简介:NUMERICALSIMULATIONOFDIMETHYLSULFIDEINTHEREMOTEMARINEBOUNDARYLAYERZhengMin(郑敏)andLiXingsheng(李兴生)NUMERICALSIMULATIONOFDIMETHY...
简介:ANALYSISOFMEANWINDCHARACTERISTICSINTHEATMOSPHERICSURFACELAYEROFTHEGRASSLANDAREAINNORTHCHINAXueHeng(薛桁),ZhuRuizhao(朱瑞兆)andWuHo...
简介:StudyontheThermalinternalBoundaryLayerandDispersionofAirPollutantinCoastalAreabyNumericalSimulation¥JiangWeimei(蒋维楣)andYuHong...
简介:Inthispaper,thesimultaneouseffectsofboundarylayerandtopographyontheinstabilityofEadywaveareinvestigatedbyusinganewparameterizationoftheverticalvelocityatthetopofPBLandtheinfluencesofthestratificationofthePBL,roughnessandtheslopeofterrainareshown.Furthermore,theeffectsoftheboundarylayerfrictionandtopographyongeneralizedEadywavearealsoinvestigated.
简介:Permittivityofaseafoamlayerisveryimportantininvestigatingoceanbrightnesstemperaturemodel.Atmicrowavefrequency,theRayleighmethodisdevelopedtoestimatetheeffectivepermittivityoftheseafoamlayer.TosimplifythetediouscalculationofseafoameffectivepermittivityatLband(1.4GHz),Pade’approximationisadoptedtofittheseafoameffectivepermittivitycomputedbytheRayleighmethod.Withthisfittingformula,anewbrightnesstemperaturemodelofseafoamlayerdefinedbycertaingeophysicalparameters,suchasairvolumefraction(AVF),seasurfacetemperature(SST),seasurfacesalinity(SSS)andthicknessoffoamlayerd,isgiven.Furthermore,thesensitivitiesofthebrightnesstemperaturemodeltoSST,SSS,dandAVFofaseafoamlayeratLbandarediscussed.Thesensitivitiesarerankedfrommosttoleastintheorder:(1)d;(2)AVF;(3)SSS;(4)SST.ThisresultindicatesthatthemeasurementerrorsofdandAVFhavesignificantimpactsontheretrievalsofSSSandSST.Withtheexperimentalbrightnesstemperaturedata,theSSSandAFVareretrievedbycostfunction.
简介:-Aone-layertime-invarianteddyviscositymodelisspecifiedtodevelopamathematicalmodelfordescribingtheessentialfeaturesoftheturbulentwaveboundarylayeroveraroughbed.Thefunctionalformoftheeddyviscosityisevaluatedbasedoncomputationalresultsfromatwo-equationturbulencemodelinwhichtheeddyviscosityvarieswithtimeandspace.Thepresenteddyviscositymodelsimplifiesmuchofthemathematicalcomplexityinmanyexistingmodels.Predictionsfromthepresentmodelhavebeencomparedwithawiderangeofexperimentaldata.Itisfoundthattheeddyviscositymodeladoptedinthepresentstudyisphysicallyreasonable.
简介:沿着在长江的更低的活动范围的Meiyu前面的重降雨事件在2009年6月23日与一个mesoscale骚乱旋涡被连接,这被发现,它从行星的边界层(PBL)发源并且以后向上发展了并且被使用过滤方法的Shuman-Shapiro发现。在在这个过程的PBL(PMDV)的mesoscale骚乱旋涡在Doppler雷达回响对应于很好短时间的暴风雨。从先进天气研究和预报模型(ARW)的高分辨率的模拟结果的分析证明沿着在PMDV的产生以前的Meiyu前面的南部的温暖的节有几表面骚乱。PMDV与mesoscale交往了对流系统(MCS)并且加强了本地对流降水。在PBL的北方和西南流动在PMDV形成的时候收敛了。同时,到旋涡的南方方面的PBL的顶上的一口西南的喷气增强了上升运动和集中。因此,shear线的强壮的冷空气流动北方什么时候shear线向南遇到了西南流动,被结束PMDV被产生。在PBL,西南风的增强,和北方风的向南方的侵略的集中线为PMDV的发展是批评的。当它在底层便于集中,潜伏的热的版本为PMDV的形成被发现关键。
简介:Globalseismicitycatalogsaresufficientforcharacterizingdoubleseismiczones(DSZs)insubductingslabandfacilitatetoestimatelayerseparationwithoutinconsistentuncertaintiesaslocalcatalogs.PreviousstudieshaveshownthecorrelationbetweenDSZslayerseparationandplateagewhilecorrelationforthoseyoungerthan~60Maissuspicious.ThelackingofDSZswithlayerseparationlessthan10kmfurthermakesitdifficulttopreciselyestimatesuchcorrelation.Thus,weincorporateeightDSZsdatadeterminedthroughlocalseismicityintoglobally-determineddatasetandreexaminesuchcorrelation.Thebestfittingresultsshowthatbothalinearmodelandasquarerootofplateagecanmathematicallyfitthelayerseparationwell.However,itisdifficulttodistinguishthesetwomodelswhenplateageisgreaterthan~20Masincetheirdifferenceislessthan2km.However,ifextrapolationispossible,bothmodelsshouldprovidephysicalinformationthatDSZswillnotformifthereisnosubductinglithosphere.Asaresult,theDSZscannotbeproduceduntiltheoceaniclithosphericagebecomesgreaterthan0.9Mainthesquarerootmodelwhilethelinearmodelgivesamisleadingresult.Assuchthesquarerootmodeldemonstratestherelationshipphysicallybetterthanthelinearone,itstillneedsfurthertestinthefuturewithmoreavailabledata,nevertheless,ourstudymightalsoprovideevidenceforthesuggestionthattheplateageisaprimarycontrolfactoroftheDSZsgeometryaswellasthesubductingprocesswhichdisregardsanylocaltectonicstresses.
简介:Theperfectlymatchedlayer(PML)isaneffectivetechniquefortruncatingunboundeddomainswithminimalspuriousreflections.Afluidparabolicequation(PE)modelapplyingPMLtechniquewaspreviouslyusedtoanalyzethesoundpropagationprobleminarange-dependentwaveguide(LuandZhu,2007).However,LuandZhuonlyconsideredastandardfluidPEtodemonstratethecapabilityofthePMLanddidnottakeimprovedone-waymodelsintoconsideration.Theyapplieda[1/1]Padéapproximanttotheparabolicequation.Thehigher-orderPEsaremoreaccuratethanstandardoneswhenaverylargeanglepropagationisconsidered.Asforrange-dependentproblems,thetechniquestohandletheverticalinterfacebetweenadjacentregionsaremainlyenergyconservingandsingle-scattering.Inthispaper,thePMLtechniqueisgeneralizedtothehigherorderelasticPE,asistothehigherorderfluidPE.Thecorrectionofenergyconservingisusedinrange-dependentwaveguides.Simulationismadeinbothacousticcasesandseismo-acousticcases.Range-independentandrange-dependentwaveguidesarebothadoptedtotesttheaccuracyandefficiencyofthismethod.ThenumericalresultsillustratethataPMLismuchmoreeffectivethananartificialabsorbinglayer(ABL)bothinacousticandseismo-acousticsoundpropagationmodeling.
简介:mesoscale在边界层和表面流动的狂暴的交换系数的计算在被改进的数字天气预言模型(MM4),被用来在mesoscale模型的预兆的结果上学习边界层parameterization计划的影响。七个不同实验计划(包括原来的MM4模型)在这份报纸设计了被几大雨格的观察数据测试以便发现改进边界层parameterization在mesoscale的计划气象学的模型。结果证明所有七个不同边界层parameterization计划在降水紧张,雨区域的分发,垂直速度,涡度和分叉地的预报上有一些影响,并且在这的改进计划糊能改进降水预报。关键词边界层parameterization-Mesoscale数字天气预言(MNWP)-狂暴的交换系数-表面流动-大雨这份报纸被中国(资助号码49875005和号码49735180)的国家自然科学基础支持。
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简介:Thestructureofatmosphericboundarylayerdeterminestheabilityofatmosphericdispersionandhasanessentialimpactonairborneaerosols.Inthispaper,thedataofaradiosoundingexperimentheldinDongguanNationalMeteorologicalObservationStation,whichisinacoastalcityinPearlRiverDelta,aswellasthedataofatmosphericaerosols,wereutilizedinordertoanalyzethecharacteristicsofatmosphericboundarylayeranditseffectsonsurfaceaerosolconcentrations.Theresultsareshowedatfollows:thelocalcirculations,associatedwithdominantwinds,madecomplexstructuresofatmosphericlayers,asthecoldairandsystematicwindsweakenedintheendofacoldairevent.Weakenedwindshearsandinversionlayers,especiallyastrongnear-surfaceinversionlayer,remarkablydiminishedtheatmosphericdiffusionabilitiesandfacilitatedanespeciallyhighconcentrationofsurfaceaerosols.Theconvergencelineorweakshearlineofseabreezeinthegroundlevelhelpsweakentheatmosphericdiffusionabilitiesandresultsinatmosphericaerosolsaccumulation.