1976世界主要河流的总矿化度运移 (Meybeck M)

HydrologicalSciences-Bulletin-desSciencesHydrologiques,XXI,26/1976TOTALMINERALDISSOLVEDTRANSPORTBYWORLDMAJORRIVERSMICHELMEYBECKLaboratoiredeGéologieDynamique,UniversitédeParis6,France*Received17November1975Abstract.WorldvariationsofdissolvedtransportTd[tkm-2year-1]andmajorioncontentS[mg1.]withrunoffg[1.s-1km-2]andsolidtransport77s[tkm-2year-1]areexaminedonthebasisof40oftheworld'sbiggestrivers(basinarea/440000km2ordischargeg5000m3s-1).Foreachriveresti­matesofA,Q,S,Tdand77saregivenandtwosubsamplesareconsideredaccordingtothesizeoftheriv­ers.ForeachsubsampleitisfoundthatSisinverselyrelatedtoq,TdisdirectlyrelatedtoqandtoTs.TheratioTs/TdishighlyvariablebutgenerallyincreaseswhenTsincreases.ClimatedominatesSvaria­tionandreliefTdvariation;widescatteringsofSandTdareduetotheotherfactor.OnaworldscalereliefisthemainfactorcontrollingvariationsofTdwith77s.ThedirectrelationshipbetweenTdandTsconfirmstheworkofAlekinandBrazhnikovaintheSovietUnion,whiletheinverserelationshipfoundbyJudsonandRitterintheconterminousUSAseemstobeaminortrendduetotheinfluenceofcli­matesurpassingrelief.Thetotalsampleofriversconsideredcovers48percentofthecontinentalareadrainingtotheoceanandrepresents44percentoftheworld'srunoff.Ifthissampleistakenasrepre­sentative,dissolvedtransportofmaterialappearstobedominantorequaltosolidtransportforabout35percentoftheworld'scontinentalsurface.Atypologyofdissolvedtransportbymajorriversisgivenaccordingtotheirmorphoclimaticfeatures.Ifchemicaltransportisamajorprocessontheearth'ssurface,thesolidmaterialcarriedbytheriverstotheoceanasawholeisfivetimesmorethanthedissolvedtrans­port:20x109tyear-1accordingtoHolemanascomparedto3.25x109tyear1onthebasisofthese40rivers.TransportenselsdissousdesplusgrandsfleuvesmondiauxResume.LesvariationsdutransportdissousTd[tkm-2an-1]etdelaconcentrationtotaleenselsdissousS[mg1_1],enfonctiondel'écoulementq[1.s-1km-2]etdutransportsolide77s[tkm-2an-1]sontétudiéessur40desplusgrandsfleuvesmondiaux(d'unesuperficiedrainéesupérieureà400000km2oud'undébitsupérieura5000m3s-1).Surl'ensembledes40fleuveslesrégressionssuivantesontététrouvées:S=392r°-62;Td=12.3?0-39;Td=6.67s0-37.LerapportTs/Tdvariede0.1àplusde30etaugmenteavecTs.LeclimatdominelesvariationsdeSetlereliefcellesdeTd;lesdispersionsimpor­tantesremarquéessontduesàl'autrefacteur.ParcontrelereliefestleprincipalfacteurcontrôlantlesvariationsdeTdenfonctiondeTs.Larelationdirectetrouvéeentre77detTsconfirmelestravauxsovié­tiquesd'AlekinetdeBrazhnikova;latendanceinversedécritepourlesEtats-UnisparJudsonetRittern'estpasreprésentativeduphénomèneàl'échellemondiale.L'ensembledesfleuvesconsidérésreprésente48pourcentdelasuperficiecontinentaledrainéeverslesocéanset44pourcentdel'écoulementexoréi-que,sicetéchantillonestreprésentatiflestransportsdissoussontsupérieursauxtransportssolidessurplusde35pourcentdelasuperficiecontinentaledrainéeverslesocéans.Lesvariationsimportantesdeq,S,Tdpermettentdeproposerunetypologiedestransportseffectuésparlesgrandsfleuvessuivantdescritèresmorphoclimatiques.Siletransportdissouscarlesrivièresestunprocessusfondamental,lesap­portssolidesàl'océanrestentglobalementbiensupérieursauxapportsdissous:20x109tan-1dema­tièressolidesd'aprèsHolemanet3.25x109tan-1dematièresdissoutes,estimationbaséesurles40grandsfleuvesétudiés.Until1960thedissolvedtransportbyrivershadbeenmuchlessstudiedbygeomorphologists,hydrologistsandgeochemiststhansolidtransport.Thelatterwasgenerallyconsideredasthemajorprocessofmaterialsupplytotheoceanandthereforesomestudiesofdenudation*Presentaddress:LaboratoiredeGéologie,EcoleNormaleSupérieure,46rued'Ulm,75005Paris,France.265ratesonlytookmechanicalerosionintoaccount.Thereisnowanewinterestinriverwaterqualitystudiesandtheseareproceedingintwomaindirections:(1)geochemicalprocessesarethoroughlystudiedonsmallrepresentativebasins(some100km2orless)whereenviron­mentalfactorscanbewelldefined(thiskindofworkwasgenerallyundertakenintheInter­nationalHydrologicalDecade),(2)ontheotherhandtheoverallgeochemicalbalancebe­tweenlandandoceanisestablishedonthebasisofinputsoftheworld'sbiggestrivers.ThisapproachwasattemptedbyAlekinandBrazhnikova(I960,1962)whoperformedintensiveworkonriversintheSovietUnion.ThefirstattempttomakeaworldsurveyofriverwaterqualitywasbyDurumetal.(1960)fortheInternationalAssociationofScientificHydrology,butthiswork,whichconcernedbothmajorandtraceelements,wasnevercompleted.In1963,Livingstonepublishedthemostcompleteliteraturereviewofsurfacewaterquality.Someotherpapersconcernedtheriverqualityofonlyonecountry,suchasJapan(Kobayashi,1960),orparticularelementsinmanyrivers(Turekian,1969;Konovalov,1970).SinceLivingstone'sreviewalotofimportantworkhasbeenattemptedontheworld'sbiggestrivers:theAmazon(Gibbs,1967,1972),Parana(DepetrisandGriffin,1968;Bonnettoetal,1969),Danube(Liepolt,1967),Mackenzie(Brunskilletal,1975),Chari(Roche,1975),Mekong(MeybeckandCarbonnel,1975).Thestudiesofrivermineralizationanddis­solvedtransporthavebeenundertakenmainlyonriverslocatedinthesamecountrywherebasinsaresometimessimilar,ortheywerebasedonworldwideriverwaterqualit