简介：在土壤外壳开发的降雨事件运动的影响经由实验室实验和基于物理的水文学反应模拟被调查。流量和土壤水内容数据被分析以便在许多降水条件下面学习不同外壳的开发时期。当一个稳定的状态，能被雨点影响的一个扩大时期打破，被发现为外壳并且，随后存在时，结果证明显著地改变的外壳的形成玷污浸透的水力的电导率(K)和流量流量特征。在K的减少为下游动人的事件象86%一样高，并且72%为在上游动人的事件，说明降雨运动的方向比降雨紧张和持续时间在外壳形成上有更重要的影响。同样下游动人的降雨事件可以比那些移动有更大的效果在上游，在雨点影响前的一个depositional外壳的发展可以在决定最后的K价值起一个重要作用。

简介：Thenumberoftropicalcyclone(TC)genesisovertheSouthChinaSeaandtheNorthwestPacificOceanin2009issignificantlylessthantheaverage(27.4).However,thenumberoflandfallTCovermainlandChinaanditsassociatedrainfallismorethantheaverage.Thispaperfocusesontheperformanceofnumericalweatherprediction(NWP)oflandfallTCprecipitationoverChinain2009.TheChinaMeteorologicalAdministration(CMA)andJapanMeteorologicalAgency(JMA)modelsarecompared.Althoughtheschemesofphysicalprocesses,thedataassimilationsystemandthedynamicframeareentirelydifferentforthetwomodels,theresultsofforecastverificationaresimilartoeachotherforTCrainfallandtrackexceptforTCGoni.Inthispaper,adaywithdailyrainfallamountgreaterthan50mmwasselectedasastormraindaywhentherewasaTCaffectingthemainland.Thereare32stormraindaysrelatedtothelandingoftyphoonsandtropicaldepressions.TherainfallforecastverificationmethodsofNationalMeteorologicalCentre(NMC)ofCMAareselectedtoverifythemodels’rainfallforecast.ObservationalprecipitationanalysesrelatedtoTCsin2009indicateaU-shapespatialdistributioninChina.Itisfoundthattherainbeltforecastedbythetwomodelswithin60hoursshowsgoodagreementwithobservations,bothinthelocationandthemaximumrainfallcenter.Beyond3days,theforecastedrainfallbeltshiftsnorthwardonaverage,andtherainfallamountofthemodelforecastsbecomesunder-predicted.TherainfallintensityofCMAmodelforecastismorereasonablethanthatofJMAmodel.Forheavyrain,theJMAmodelmademoremissingforecasts.TheTCrainfallisverifiedinGuangdong,Guangxi,FujianandHainanwhererainfallamountrelatedtoTCsisrelativelylargerthaninotherregions.TheresultsindicatethatthemodelforecastforGuangdongandGuangxiismoreskillfulthanthatforHainan.TherainfallforecastforHainanremainsdifficultforthemodelsbecauseofinsufficientobse

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.

简介：Reliablefielddataforallhydrologicparametersareoftenunavailableforwatershedsevenforthoseintensivelymonitored.Intheabsenceofreliablesuchdata,verifiedmathematicalrelationsforanareacanbeusedforotherareaswithsamehydrologicandclimaticregimes.Theobjectivesofthisresearchwere:1)toassessthetotalrunoffandsedimentloss,and2)todeveloprainfall,runoffandsoillossrelationsforfourprominentlanduses(includingdegraded,pasture,forestandagriculturelands)intheHilkotwatershed(Pakistan).Fourexperimentalnaturalrunoffplotswereestablishedonthelanduses(degraded,pasture,forestandagricultureland).ThefieldstudyanddatacollectionwereconductedintheHilkotwatershedfrom1999to2005.Regressionanalysiswasconductedtoestablishrelationsamongrainfall,runoffandsoillossforalllandusesusing.Regressionanalysisindicatedgoodcorrelationwithfielddata.

简介：Thespring(March-April-May)rainfallovernorthernChina(SPRNC)ispredictedbyusingtheinterannualincrementapproach.DYdenotesthedifferencebetweenthecurrentyearandpreviousyears.TheseasonalforecastmodelfortheDYofSPRNCisconstructedbasedonthedatathataretakenfromthe1965-2002period(38years),inwhichsixpredictorsareavailablenolaterthanthecurrentmonthofFebruary.Thisisfavorablesothattheseasonalforecastscanbemadeonemonthahead.Then,SPRNCandthepercentageanomalyofSPRNCareobtainedbythepredictedDYofSPRNC.Themodelperformswellinthepredictionoftheinter-annualvariationoftheDYofSPRNCduring1965-2002,withacorrelationcoefficientbetweenthepredictedandobservedDYofSPRNCof0.87.Thisaccountsfor76%ofthetotalvariance,withalowvaluefortheaveragerootmeansquareerror(RMSE)of20%.Boththeresultsofthehindcastfortheperiodof2003-2010(eightyears)andthecross-validationtestfortheperiodof1965-2009(45years)illustratethegoodpredictioncapabilityofthemodel,withasmallmeanrelativeerrorof10%,anRMSEof17%andahighrateofcoherenceof87.5%forthehindcastsofthepercentageanomalyofSPRNC.