简介：Atwo-dimensional,semi-geostrophicnumericalmodelincorporatingthetropopauseandstratosphereisusedtoinvestigatetheeffectsofapositivepotentialvorticityanomalyandlatentheatreleaseonthefrontogeneticprocessandthestructureoftheresultingfrontalzone.Itisdemonstratedthat(1)theinclusionoftropopauseandstratospheresignificantlychangesthefrontalstructureonlyintheupperlevels;(2)aclearlydefinedquasi-equivalentbarotropicstructureandaregionofupwardmotionoffinitewidthappearwhenapositivepotentialvorticityanomalyexistsonthewarmsideofthemaximumbaroclinityinthelowertroposphere,especiallywhenitislocatedonthesouthedgeofthebarocliniczone;(3)theabovementionedstructuredeterioratesasthefrontogenesisproceedsinadryatmospherebutcanbemaintainedinamoistfrontogeneticprocesswithcondensationalheating;(4)thecombinationofapositivepotentialvorticityanomalyandthelatentheatreleaseisabletoacceleratethefrontogenesissignificantlywiththetimeneededtoformanintensefrontalzonereducedtolessthan15h.Theresultshavesignificanttheoreticalimportanceinunderstandingthecomplexnatureoffrontalstructureandfrontogenesis,especiallyinunderstandingthedynamicstructureofthesubtropicalfrontalzoneobservedduringearlysummeroverEastAsia.

简介：Threetyphoons,Goni,MorakotandEtauwhichweregeneratedinWesternPacificin2009,aresuccessfullysimulatedbytheWRFmodel.Thehorizontalandverticalvorticityandtheirinteractionareanalyzedanddiagnosedbyusingthesimulationresults.Itisshownthattheirresultantvectorshadafixedpatternintheevolutionprocessofthethreetyphoons:Thehorizontalvorticityconvergedtothetropicalcyclone(TC)centerbelow900hPalevel,flowedoutfromitataround900to800hPa,andflowedinbetween800hPaand700hPa.Ifmultiplemaximumwindspeedcentersshowedup,thehorizontalvorticityconvergedtothecenterofthetyphoonbelowthemaximumwindspeedcenteranddivergedfromtheTCcenterabovethemaximumwindspeedcenter.Atlowlevels,thethreetyphoonsinteractedwitheachotherthroughverticalcirculationgeneratedbythevortextube.Thiscirculationwasmainlygeneratedbytheeastwardorwestwardhorizontalvorticityvectors.Cloudsandprecipitationweregeneratedontheascendingbranchoftheverticalcirculation.ThevortextubesoftenflowedtowardthesouthwestoftherightTCfromthenortheastoftheleftTC.Accordingtothefullvorticityequation,thehorizontalvorticityconvertedintotheverticalvorticitynearthemaximumwindspeedcenterbelow850hPalevel,andtheperiodofmostintenseconversionwasconsistentwiththeintensificationperiodofTC,whilethevorticityadvectionwasagainsttheintensification.Theverticalvorticityconvertedintothehorizontalvorticityfrom800hPato600hPa,andthewindspeeddecreasedabovethemaximumwindspeedregionatlowlevels.

简介：Anf-planequasi-geostrophicbarotropicvorticityequationmodelofhighresolutionisdesignedinthispaperinordertoinvestigatethecharactersofvorticitypropagationandtheeffectofnonlinearityonthepropagationwithinatyphooncirculation,whereintwomesoscalevorticescoexistatdifferentradialpositions.Theresultsof10setsofexperimentssuggestthatincomparisonwithonlyonevortex,theintensityoftheinwardpropagationsofvorticitystrengthensdistinctly,vorticitydetainsintheinnerregionoftyphooncirculationforalongertime,andthelocalmaximumwindspeedintheinnerregionincreasesclearly.Theintroductionofnonlinearadvectionintothemodelweakenstheintensityofbothinwardandoutwardpropagationsofvorticity,butmakestheinwardpropagationuptoapositionclosertothecenteroftyphoon.

简介：在生气增加形式的动量移流涡度方程被介绍，在哪个在经典涡度方程的分叉术语不明确地出现。这个方程包括水平风移流的旋转效果，它明确地没在经典涡度方程被包括。涡度和它发生在2008年7月的台风Fung-Wong(0808)的趋势被分析。计算结果证明水平风的移流的旋转效果是在在它的生命周期期间为Fung-Wong决定垂直涡度的变化的一个领先的因素，特别在乍见陆地导致的时期。移流学期代表垂直涡度的趋势变化，并且垂直涡度趋势的积极值的区域几乎与Fung-Wong的轨道一致，它可以作为一个因素被拿定位Fung-Wong的关键观察区域。方程为与水平风的强壮的移流联系的系统提供一个增补诊断工具。

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简介：TheintrinsicphysicalrelationshipofvorticitybetweenmodesAandBinthethree-dimensionalwaketransitionisinvestigated.Directnumericalsimulationsfortheflowpastasquare-sectioncylinderarecarriedoutatReynoldsnumbersof180and250,associatedwithmodesAandB,respectively.Basedontheanalysisofspacialdistributionsofvorticityinthenearwake,characteristicsoftheverticalvorticityinmodesAandBareidentified.Moreover,therelationshipofthreevorticitycomponentswithspecificsignsissummarizedintotwosignlaws,asintrinsicphysicalrelationshipsbetweentwoinstabilitymodes.Bythetheoryofvortex-inducedvortex,suchtwosignlawsconfirmthattherearetwoandonlytwokindsofvortex-sheddingpatternsinthenearwake,justcorrespondingtomodesAandB.Inbrief,alongthefreestreamdirection,modeAcanbedescribedbytheparallelsheddingverticalvorticeswiththesamesign,whilemodeBisdescribedbytheparallelsheddingstreamwisevorticeswiththesamesign.Finally,itisfoundoutthatthe-typevortexisabasickindofvortexstructureinbothmodesAandB.

简介：在2015年9月8-9日发生在四川省上的一个地区性的重降水事件基于从气象站获得的时时观察的降水数据和NCEPFNL数据被分析。二个潮湿的动态参数，即，潮湿的涡度(m)和潮湿的分叉(m)，被用来诊断这个重降水事件。结果证明在西南的中国上的地形学有这二个参数的能力上的重要影响诊断降水。当地形学的影响是弱的时(即，低高度)，m不能确切在事件的起始的阶段描绘降水的地点。然后，当降水发展，它描绘地点的能力显著地改善。特别地，m在事件的山峰阶段期间与降水的地点与最好一致。而且，m中心的进化与降水中心的进化显示出高一致性。为m，尽管一些虚惊的区域是明显的，它几乎完全在降水事件期间反映降水的地点。然而，m中心与降水中心显示出矛盾。这些结果建议m和m有一个重要能力预言降水的地点。而且，m以预言降水中心的可变性比m有一个更强壮的能力。不管多么当地形学的影响是强壮的时(即，高高度)，这两二个潮湿的动态参数是不能的在全部降水事件期间描绘降水的地点和中心，建议他们的弱能力在复杂地形学上预言降水。

简介：这份报纸测试在与奔流的雨联系的异例由使用第五产生的NCAR/佩恩状态Mesoscale模型(MM5)输出的好模型模拟数据由台风No.9914(丹)引起了的潮湿的潜在的涡度(MPV)上强迫的导致云的质量的影响。诊断结果证明积极MPV异例区域，它被从600hPa集成MPV到300hPa在获得垂直，粗略地在位置或在分发模式在他们的同步阶段与降水与一致，并且丹的最大的积极MPV区域主要在600hPa和300hPa之间被定位，它比奔流的雨盒子高得多。进一步的分析也证明积极MPV异例的值与丹的开发增加了或减少，并且积极MPV异例可以也作为tracer被服务显示热带气旋紧张的进化。

简介：TheforcingofanomalousdivergentwindandtransientvorticityfluxestotheanomalyofstationarywavesofDJF(December—January—February)1982/1983isstudied.Theresultsshowthattheanomalyofthetransientvorticityfluxconvergencetendstocancelordissipatetheanomalyofthevorticitysourcesgeneratedbydivergentwind.Thestationarywaveanomaliesaremaintainedbybothoftheseforcings.Itisalsofoundthat,fortheDJF1982/1983case,bothofthevorticitysourceanomalyoverthetropicalandequatorialeasternPacificandthatoverthemidlatitudeNorthPacificareimportanttomaintaintheatmosphericcirculationanomalyoverthePacific/NorthAmericaregion.

简介：ThemesoscalemodelMM4isusedtosimulatethetorrentialrainassociatedwithMeiyufrontoccurringon5—6July.1991intheChangjiang-HuaiheBasin.Basedontheoutputsofthemodel,thecauseofthemesoscalecyclogenesisonthelowertroposphereisinvestigatedintermsofthepotentialvorticityprinciple.Theresultsshowthatbecauseofthefavorablepatternofmoistisentropicsurface,theabsolutevorticityincreaseswhencoldairwithhighmoistpotentialvorticityvaluerapidlyslidesdownsouthwardsalongthemoistisentropicsurface,andthencausesthecyclonicvortexdevelopment.

简介：Aheavyrainfallprocess,whichoccurredinShanghaiduring5-6August,2001fromalandfallingtropicaldepression(TD),isexaminedwithacontrolnumericalexperimentbasedonMM5model.Itisfoundthatthecontoursofgeneralizedequivalentpotentialtemperature(θ*)arealmostverticalwithrespecttohorizontalsurfacesneartheTDcenterandmoredenselydistributedthanthoseofequivalentpotentialtemperature(θe).Becausetheatmosphereisnon-uniformlysaturatedinreality,θ*takestheplaceofθeinthedefinitionofconvectivevorticityvector(CVV)sothatanewvector,namelythegeneralizedconvectivevorticityvector(CVV*),isappliedinthisstudy.SinceCVV*canreflectboththesecondarycirculationandthevariationofhorizontalmoistbaroclinicity,theverticalintegrationofverticalcomponentofCVV*isfound,inthisstudy,torepresenttherainfallareasintheTDcasebetterthanpotentialvorticity(PV),moistpotentialvorticity(MPV),generalizedmoistpotentialvorticity(Pm),andCVV,withhigh-valueareaofCVV*correspondingtoheavy-rainfallarea.Moreover,theanalysisfromCVV*impliesthattheHangzhouBaymightplayanimportantroleintheheavyrainprocess.AsensitivityexperimentwithouttheHangzhouBayisthendesignedandcomparedwiththecontrolrun.ItisfoundthattheCVV*becomesweakerthanthatinthecontrolrun,implyingthattheeliminationofHangzhouBayresultsinreducedrainfall.FurtheranalysesshowthattheHangzhouBayprovidessufficientwatervaporandsurfaceheatfluxtotheTDsystem,whichisveryimportanttothegenesisanddevelopmentofmesoscalecloudclustersaroundtheTDandtheassociatedheavyrainfall.

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简介：与潜在的涡度(PV)在这篇论文，潜在的涡度结构和在在212003年6月23日期间的长江和Huaihe河山谷上的风暴之发展形成的倒置被调查框架。风暴之发展形成被一个lower-troposphericPV异例主要由于潜伏的热版本在早阶段在长江和Huaihe河山谷上表明，它极大地影响由片表明了明智的PV倒置的联系lower-tropospheric重力势高度和风领域的进化。在以后的阶段，一个upper-troposphericPV异例发展，导致在在两个的气旋上的垅的生长在上游、下游，它为低级气旋发展提供一块有利背景地。但是表面热反常的效果总是在这风暴之发展形成期间阻碍气旋的发展到不同程度。位置和PV异例的力量是，这进一步被表明仔细，与低级气旋有关，开发，和lower-troposphericPV异例似乎例如，组成最重要的特征贡献大约60%到低级喷气(LLJ)。

简介：ＦＯＵＲＩＥＲ－ＣＨＥＢＹＳＨＥＶＳＰＥＣＴＲＡＬＭＥＴＨＯＤＦＯＲＳＯＬＶＩＮＧＴＨＲＥＥ－ＤＩＭＥＮＳＩＯＮＡＬＶＯＲＴＩＣＩＴＹＥＱＵＡＴＩＯＮＧＵＯＢＥＮＹＵ（郭本瑜）；ＬＩＪＩＡＮ（李健）；ＭＡＨＥＰＩＮＧ（马和平）（Ｄｅｐａｒｔｍｅｎｔｏ...

简介：Thepresentworkprovidesanovelmethodforcalculatingverticalvelocitybasedoncontinuityequationsinapressurecoordinatesystem.Themethodovercomesthedisadvantageofaccumulationofcalculatingerrorsofhorizontaldivergenceincurrentkinematicsmethodsduringtheintegrationforcalculatingverticalvelocity,andconsequentlyavoidsitssubsequentcorrection.Inaddition,throughmodificationsofthecontinuityequations,itshowsthatthevorticityoftheverticalshearvector(VVSV)isproportionalto-ω,theverticalvelocityinpcoordinates.Furthermore,ifthechangeofωinthehorizontaldirectionisneglected,thevorticityofthehorizontalvorticityvectorisproportionalto-ω.Whenωisunderafluctuatingstateintheverticaldirection,theupdraftoccurswhenthevectorofhorizontalvorticityrotatescounterclockwise;thedowndraftoccurswhenrotatingclockwise.ThevalidationresultindicatesthatthepresentmethodisgenerallybetterthantheverticalvelocitycalculatedbytheωequationusingthewetQ-vectordivergenceasaforcingterm,andtheverticalvelocitycalculatedbyutilizingthekinematicsmethodisfollowedbytheO’Brienmethodforcorrection.Theplus-minussignoftheverticalvelocityobtainedwiththismethodisnotcorrelatedwiththeintensityofdBZ,buttheabsoluteerrorincreaseswhendBZis>=40.Thismethoddemonstratesthatitisagoodreflectionofthedirectionoftheverticalvelocity.

简介：Inthispaper,Chebyshevpseudospectral-finiteelementschemesareproposedforsolvingthreedimensionalvorticityequation.SomeapproximationresultsinnonisotropicSobolevspacesaregiven.Thegeneralizedstabilityandtheconvergenceareprovedstrictly.Thenumericalresultsshowtheadvantagesofthismethod.Thetechniqueinthispaperisalsoapplicabletootherthree-dimensionalnonlinearproblemsinfluiddynamics.

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简介：我们与紧缩、光滑的边界在n在一般的域为不可压缩的液体学习海军司烧方程的起始边界的值问题，题目到运动学并且非扁平的边界上的涡度边界条件。我们观察到在nonhomogeneous边界条件下面，压力p能被为泊松方程解决Neumann问题仍然恢复。然后，我们建立well-posedness不稳定司烧方程并且采用答案与绝对边界条件把我们的起始边界的价值问题简化为一个起始边界的价值问题。基于这，我们首先与绝对边界条件和起始的条件为一个适当本地线性化的问题建立well-posedness(没有不可压缩性条件)，它建立印射的速度。然后，我们为印射的速度开发自原因推及结果的估计，特别为印射处理复杂边界的时间衍生物包含Sobolev标准调节，它导致印射和我们的起始边界的值问题的答案的存在的固定的点的存在。最后，当粘性系数趋于时，我们建立那零，在n的起始边界的价值问题的强壮的答案(n鈮?3)在L2与nonhomogeneous涡度边界状况收敛到相应Euler方程令人满意运动学的条件。

简介：在断热的状况下面的垂直涡度的发展被潜在的涡度和潜在的温度(PV-)并且从一个Lagrangian观点的看法的优点调查。概括倾斜的涡度开发(GSVD)的一个新概念为断热的状况被介绍。当一个粒子在稳定或不稳定的状况下面在凹面斜坡下面或在严厉地倾斜的isentropic表面的凸的斜坡上面正在滑动时，GSVD是涡度开发(VD)的一个并列独立框架，它包括倾斜的涡度开发(SVD)。SVD是为与垂直涡度的快速的开发学习严重天气系统的特殊VD。另外，GSVD澄清VD和SVD。为VD和SVD的标准证明对SVD的要求更比对VD的要求被限制。当一个空气包裹在凹面斜坡下面或在严厉地倾斜的isentropic的凸的斜坡上面是动人的时，在稳定的成层的气氛出现，它的稳定性减少，或在有它的稳定性的不稳定的气氛增加即，它的稳定性z接近零，如果它的CD正在减少，它的垂直涡度能很快发展。理论结果被采用分析旋涡(TPV)出现在TP上，然后滑动了在下面并且移动的一个西藏的高原(TP)在2008年7月下旬东方，在四川省并且沿着长江的中间、更低的活动范围导致重降雨。当它在四川盆的东北边的upslope上向上滑动了时，PV2的变化从0000～0600UTC222008年7月贡献了TPV的增强，自从在两水平涡度s和baroclinitys的变化在垂直涡度的发展有积极效果。在0600UTC222008年7月，为在300Kisentropic表面的SVD的标准满足，意味着SVD显著地发生了并且作出贡献到垂直涡度的发展。有关包围旋涡的VD和SVD的更强壮的信号的外观显示GSVD概念能为诊断天气系统的开发用作一个有用工具。

简介：Usingreal-timedataandtheWRFmesoscalemodel,aheavyraineventintheprocessofMesoscaleConvectiveComplex(MCC)turningintobandedMesoscaleConvectiveSystems(MCSs)during18-19June2010issimulatedandanalyzedinthispaper.Theresultsindicatedthattheformationandmaintenanceofasouthwestvortexandshearlineat850hPawasthemesoscalesystemthataffectedtheproductionofthisheavyrain.Thelow-vortexheavyrainmainlyhappenedinthedevelopmentstageofMCC,andthecircularMCCturnedintobandedMCSsinthelatestagewithmainlyshearlineprecipitation.Inthevicinityofrainfallarea,theintensehorizontalvorticityduetotheverticalshearofuandvcausedtherotation,andincorrespondence,theascendingbranchoftheverticalcirculationtriggeredtheformationofheavyrain.Thedifferentdistributionsofuandvintheverticaldirectionproducedvaryingverticalcirculations.Thehorizontalvorticitynearthelow-vortexandshearlinehadobviousdifferenceswhichledtovaryingreasonsforheavyrainformation.Thelow-vortexheavyrainwasmainlycausedbytheverticalshearofv,andtheshearlinerainfallformedowingtotheverticalshearofbothuandv.Inthisprocess,theverticalshearofvconstitutedtheEW-trendingrainbandalongtheshearline,andthelatitudinalnon-uniformityoftheverticalshearinucausedtheverticalmotion,whichwascloselyrelatedtothegenerationanddevelopmentofMCSsattheshearlineandtheformationofmultiplerainclusters.Therewasalsoasimilardifferenceinthepositively-tiltingterm(conversionfromhorizontalvorticitytoverticalpositivevorticity)neartherainfallcenterbetweenthelow-vortexandtheshearline.Theconversioninthelowvortexwasmainlydeterminedbyбv/бp<0,whilethatoftheshearlinebyбu/бp<0.Thescaleoftheconversionfromthehorizontalvorticitytoverticalvorticitywasrelativelysmall,anditwaseasilyignoredintheaveragedstate.Thetwistingtermwasmainlyconducivetothereinfor