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coordinatesystemofwater - energypartitioningwasestablishedtoquantifyeffectsofclimateandunderlyingsurface
variationonevapotranspirationseparately.Thentheoptimizedwater - energypartitioningframeworkwasappliedto
makeattributionofactualevapotranspirationin83typicalwatershedsin1900 - 2008.Itisdetectedthatvariationof
evapotranspirationinhumidbasinswithlowwaterholdingcapacityismainlydrivenbyunderlyingsurfacefactors
whileinhumidwatershedwithhighwaterholdingcapacity ,climatefactorscontributemoretoevapotranspiration.
Thetrajectoryofhydro - thermalstateinsemi - humid,aridandsemi - aridbasinswithlowwater - holdingcapacity
mainlymovesalongthearidityindexline,indicatingthatevapotranspirationismainlydrivenbyunderlyingsurface
factors.ComparingcalculationresultsbythismethodwiththosebasedonBudyko - Fudecompositionmethod,it
showsthattheattributionmethodbasedonthewater - energypartitioningframeworkhasagoodreliability.Inaddi
tion ,comparingtothetraditionalBudyko - Fudecompositionmethod,thespatialcoordinatediagramofwater - ener
gypartitioningisabletointuitivelyanalyzebothcontributionanddirectionofclimateandunderlyingsurfacechanges
toevapotranspirationinriverbasins ,aswellasthechangetrackofwater - energystateinthebasinunderdifferent
periods,whichmightmakeastrongpracticabilityinthefuture.
Keywords:spatialcoordinatesystem ofwater - energypartitioning;ecohydrologicalframework;Budyko - Fude
compositionmethod;attributionanalysis;globalbasins
(责任编辑:于福亮)
(上接第 1228页)
Researchonthedynamicsoftheupliftandtransportcharacteristicsof
sedimentintheLowerYellowRiverChannel
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CAIRongrong,ZHANGHongwu,ZHANGYu,ZHANGLuohao
(1.InternationalEconomic&TechnicalCooperationandExchangeCenter,MinistryofWaterResources,Beijing 100038,China;
2.YellowRiverResearchCenter,TsinghuaUniversity,Beijing 100084,China;
3.StateKeyLaboratoryofHydroscienceandEngineering,TsinghuaUniversity,Beijing 100084,China)
Abstract:Inthispaper,thedynamicsoftheupliftandtransportcharacteristicsofsedimentintheriverchannel
oftheLowerYellowRiver (LYR)areinvestigatedonthebasisofpreviousstudiesusingalargeamountofhydro
logicaldata.AnupliftflowvelocityformulawithaclearconceptionandsuitablefortheLYRischosenbasedon
thegrainsizedistributiondata.Forthefinesediment ,thefourcandidateformulas(derivedbyShaYuqing,Dou
Guoren ,ZhangLuohao,andLuoShiqi)areallapplicabletotheYellowRiver.Forcoarsesediment,theformu
lasderivedrespectivelybyZhangLuohaoandLuoShiqiaremoresuitablethantheothertwo.Theupliftcharacter
isticsofsedimentintheLYRareinvestigatedbasedontheformuladerivedbyZhangLuohao,whichindicatesthat
coarsesedimentupliftalsooccursinthechannelofLYR underthemoderatefloodcondition.Then ,theHua
yuankoustation,theGaocunstation,andtheLijinstationintheLYRareselectedastherepresentativehydrolog
icalstations.Thediagramsoftheflowdischargeversustheratioofsedimentinsuspendedstatusareplottedre
spectivelybasedonthemeasureddatalowerthanthebankfulldischargeinthefloodseasonofthethreestations.
Theresultsshowthatthesedimenttransportcharacteristicsofthethreestationsaresimilarafterintroducingthe
conceptofupliftcriticalflowdischarge.Furthermore ,byanalyzingthesedimenttransportcharacteristicsofeach
station,therelationshipbetweenthesedimentparticlesizeandthefactorsrelatedtotheprobabilityofthesuspen
dedmovement,i.e.,theupliftcriticalflowdischarge,upliftprobabilitycoefficient,andthesedimenttransport
indexisgiven,basedonwhichtheequationbetweentheratioofsedimentinsuspendedstatusandtheflow - sedi
mentfactorsisfinallyestablished.Withtheproposedequation ,itshowsthatthecoarseparticlesinthecomposi
tionofsuspendedsedimentcanstillmaintainthesuspendedstatusaslongasthedailyaveragedischargeofthe
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LYRexceeds971m ?s(obtainedfromtherequireddischargetomatchthepredictedreductionofannualaverage
sedimenttransportinthenext30years ),whichindicatesthatincreasingthedischargeisaneffectiveapproachto
directlyenhancethesedimenttransportcapacityoftheLYR.
Keywords: TheLowerYellow River; sediment; upliftflow velocity; sedimenttransportdynamics; flow-
sedimentfactors
(责任编辑:李福田)
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