简介:Theinterestinthenationallevelsoftheterrestrialcarbonsinkanditsspatialandtemporalvariabil-itywiththeclimateandCO2concentrationshasbeenincreasing.HowtheclimateandtheincreasingatmosphericCO2concentrationsinthelastcenturyaffectthecarbonstorageincontinentalChinawasin-vestigatedinthisstudybyusingtheModifiedSheffeldDynamicGlobalVegetationModel(M-SDGVM).TheestimatesoftheM-SDGVMindicatedthatduringthepast100yearsacombinationofincreasingCO2withhistoricaltemperatureandprecipitationvariabilityincontinentalChinahavecausedthetotalvege-tationcarbonstoragetoincreaseby2.04PgC,with2.07PgCgainedinthevegetationbiomassbut0.03PgClostfromtheorganicsoilcarbonmatter.TheincreasingCO2concentrationinthe20thcenturyisprimarilyresponsiblefortheincreaseofthetotalpotentialvegetationcarbon.Thesefactorialexperimentsshowthattemperaturevariabilityalonedecreasesthetotalcarbonstorageby1.36PgCandprecipitationvariabilityalonecausesalossof1.99PgC.TheeffectoftheincreasingCO2concentrationaloneincreasedthetotalcarbonstorageinthepotentialvegetationofChinaby3.22PgCoverthepast100years.Withthechangingoftheclimate,theCO2fertilizationonChina'secosystemsistheresultoftheenhancednetbiomeproduction(NBP),whichiscausedbyagreaterstimulationofthegrossprimaryproduction(GPP)thanthetotalsoil-vegetationrespiration.OurstudyalsoshowsnotableinterannualanddecadalvariationsinthenetcarbonexchangebetweentheatmosphereandterrestrialecosystemsinChinaduetothehistoricalclimatevariability.
简介:TheaimofthisworkisanimprovementoftheparameterizationofthesoilmoistureintheschemeoftheLandSurfaceProcessModel(LSPM)forapplicationsoverdesertareas.Infact,inverydryconditions,thewatervapourfluxplaysanimportantroleintheevaporationprocessesandinfluencestheundergroundprofilesofhumidityandtemperature.TheimprovedversionofsoilmoistureparametcrizationintheLSPMschemehasbeencheckedbyusingthedatatakenfromthedatabaseofthefieldexperimentHAPEX-Sahel(Hydrology-AtmospherePilotExperimentintheSahel,1990-1992).ModelsimulationsrefertothreedifferentstationslocatedinNiger(Fallow,MilletandTigersites)whereinputdataforLSPMandobservationsweresimultaneouslyavailable.TheresultsofsimulationstakingintoaccountthewatervapourfluxinthesoilmodelLSPM,seemtocomparebetterwiththeobservedbehaviourofsoilmoistureandturbulentheatfluxesthanthoseoverlookingthewatervapourflux,confirmingthegreatimportanceofthewatervapourinsuchdryconditions.
简介:在中国上的暴风雪的第三个阶段的energetics用ECWMF数据被分析。为中东马槽和在25282008年1月上向中国发展了的西方的和平的马槽的精力预算的分析由是关键来源和与马槽联系的旋涡动能中心的主要水池的ageostrophic风显示出geopotential的移流。精力变换学期,相互作用动能变换和baroclinic变换的大小,太小,不能解释精力中心和喷气条纹的发展。精力中心经由ageostrophicgeopotential流动的集中在他们的入口区域获得了精力,然后由一样的流动在他们的出口区域失去了精力。在入口区域,流动收敛了,增加geopotential坡度,它产生了更大的因地球自转而引起的风和更高的动能,导致在这个区域的一个上升运动。当马槽搬到中国时,流动的集中在入口区域引起的上升运动在中央、南部的中国上加强了暴风雪。
简介:Avariationaltechnique(VT)isappliedtoestimatesurfacesensibleandlatentheatfluxesbasedonobservationsofairtemperature,windspeed,andhumidity,respectively,atthreeheights(1m,4m,and10m),andthesurfaceenergyandradiationbudgetsbythesurfaceenergyandradiationsystem(SERBS).Themethodfullyusesallinformationprovidedbythemeasurementsofairtemperature,wind,andhumidityprofiles,thesurfaceenergybudget,andthesimilarityprofileformulaeaswell.DatacollectedatFeixiexperimentstationinstalledbytheChinaHeavyRainExperimentandStudy(HeRES)Programareusedtotestthemethod.Resultsshowthattheproposedtechniquecanovercomethewell-knownunstablilityproblemthatoccurswhentheBowenmethodbecomessingular;incomparisonwiththeprofilemethod,itreducesboththesensitivitiesoflatentheatfluxestoobservationalerrorsinhumidityandthoseofsensibleheatfluxestoobservationalerrorsintemperature,whiletheestimatedheatfluxesapproximatelysatisfythesurfaceenergybudget.Therefore,thevariationaltechniqueismorereliableandstablethanthetwoconventionalmethodsinestimatingsurfacesensibleandlatentheatfluxes.
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简介:Inaccordancewithanewcompensationprincipleofdiscretecomputations,thetraditionalmeteo-rologicalglobal(pseudo-)spectralschemesofbarotropicprimitiveequation(s)aretransformedintoperfectenergyconservativefidelityschemes,thusresolvingtheproblemsofbothnonlinearcomputa-tionalinstabilityandincompleteenergyconservation,andraisingthecomputationalefficiencyofthetraditionalschemes.Asthenumericaltestsofthenewschemesdemonstrate,insolvingtheproblemofenergyconser-vationinoperationalcomputations,thenewschemescaneliminatethe(nonlinear)computationalin-stabilityand,tosomeextenteventhe(nonlinear)computationaldivergingasfoundinthetraditionalschemes,Furthercontrastsbetweennewandtraditionalschemesalsoindicatethat,indiscreteopera-tionalcomputations,thenewschemeinthecaseofnondivergenceiscapableofprolongingthevalidin-tegraltimeofthecorrespondingtraditionalscheme,andeliminatingcertainkindofsystematicalcom-putational“climatedrift”,meanwhileincreasingitscomputationalaccuracyandreducingitsamountofcomputation.Theworkingprincipleofthispaperisalsoapplicabletotheproblemconcerningbaroclin-icprimitiveequations.
简介:在在过去的几十年的陆地表面过程的理解变化在响应气候的流动改变的表面精力要求趋势和interannual可变性的知识。在我们的学习,社区陆地模型版本3.5(CLM3.5),从普林斯顿大学由最近的更新的混合reanalysis观察的表面气候数据开车,被用来在1948~2000期间获得表面精力流动的全球分布。把数据和模拟结果,长期的趋势和气候的变量和表面精力流动的interannual可变性(IAV)基于气候因为50+年的这跨度被导出并且分析。有为气候的变量和表面精力流动的强壮的长期的趋势和大IAV的区域被识别。这些分析在气候和表面流动的空间模式揭示季节的变化;然而,在为在0年不充分做的过去的锝?上的表面精力流动的趋势和IAV的空间模式为气候的变量对应于那些,显示到在气候的forcings的变化的陆地表面的复杂回答。
简介:Characteristicsofthewavesources,energypropagationandconversionforanomalousRossbywaveactivities(RWAs)alongtheWestAsianjetstream(WAJS)insummerareexaminedbasedontheNCEP/NCAR(NationalCentersforEnvironmentalPrediction/NationalCenterforAtmosphericResearch)reanalysisdatafrom1958to2003,usingthevorticitysourceequation,theEliassen-Palm(EP)flux,andthewaveenergyequationunderdiabaticheating.ThestudyaimstofindthedynamicalcausesforRWAanomaliesalongtheWAJSandtoimprovetheunderstandingofmid-highlatitudecirculationanomalies.TheresultsshowthatthenegativevorticitysourceandthestrongEPfluxdivergenceovertheMediterraneanSeaandtheNorthAtlantic-ScandinavianPeninsulaareaactasthewavesourcesforRWAanomaliesalongtheWAJS.Whentheintensityandpositionofthewavesourcesareanomalous,theexcitedeastward-propagatingRWAalongtheWAJSalsobehavesanomalously.Instrong(weak)yearsofRWA,RossbywavesexcitedbythestrongdivergenceofEPfluxesovertheIceland-ScandinavianPeninsulaarea(easttotheScandinavianPeninsula)propagateeastwardandsoutheastward.Theeastwardpropagatingwavesbecomestrengthened(weakened)afterturningsoutheastwardneartheUralMountainsandthenenteringtheAsiansubtropicalwesterlyjetstream(ASWJS)overtheCaspianSea-AralSea-Xinjiang.Thesoutheastwardpropagatingwavesalsostrengthen(weaken)afterdirectlyenteringtheASWJSovertheeasternMediterranean-theBlackSea.Furthermore,thedivergenceofEPfluxesovertheMediterraneanalsostrengthens(weakens)inthestrong(weak)years,sotheyjointlybringaboutthestrong(weak)RWAalongtheWAJS.Finally,thepertur-bationavailablepotentialenergy(PAPE)alongtheWAJS(15°-60°E)producedbydiabaticheating,isfargreaterthantheconversionfromthekineticenergyofthebasicflowintotheperturbationkineticenergyandfromtheavailablepotentialenergyofthebasicflowintoPAPE.TheRWAalongtheWA