简介：BasedonthebiogeochemicalstudiesonnutrientelementsintheChangjiangestuary,themainresultsandrecentprogressesarereviewedinthispaper,suchasthenutrientfluxesintothesea,themixingbehaviors,thedistributioncharacteristicsandtransportationaswellasthebiogeochemicalbehaviorsofnutrientsintheplumefrontalregion.Theexploringdirectionsandresearchemphasesinthefutureareproposed.

简介：ThecircumfluencearoundtheJiuduanSandbankisthoroughlystudiedbymeansoftheprinci-pleofleastresistanceinfluiddynamics.ThediversionratiooftheNorthChannelfor1998iscalculated,whichisalmostthesameasthefieldsurveydata.ThenormalandminimumdiversionratiosoftheNorthChannelafterstagesⅠ,ⅡandⅢregulationworksaswellasthefuturephaseareobtained.Thenumeri-calresultsandpredictedvalueareaccurate.

简介：-ThispaperdescribesaradioactivetracerexperimentcarriedoutatthelandwardspoilsiteoftheNorthPassageintheYangtzeEstuaryinJune,1991.Scandium-46wasselectedasthetracer,thetotalactivityreleasedwas179.45GBqandtheamountoftheSandium-46glasswas495g.Thepurposeoftheexperimentwastodeterminethesedimentmovementdirection,path,velocityandtransportrate,andtherefore,toprovidedirectevidenceforusingthelandwardspoilsiteinthefuture.Theexperimentalresultsshowedthatthesedimentmovementwasgovernedbytheebbtidecurrentduringtheperiodofmeanandneaptideswhentheradioactivetracerwasinjectedbothonthefloodandebbtides,andthesedimentmovedfromthereleasepointtothemiddleoftheNorthPassagenearnavigationbuoyNo.269.Thedirecitonofthesedimentmovementwas110°,theparticlevelocitywas758m/d,andthesedimenttransportrateperunitwidthwas47.8m3/md.

简介：BasedonanalysesofsurfaceandcoresedimentsinthetidalflatsoftheYangtzeEstuaryandcoastalareas,thepresentstudyrevealsphosphorousformsexistinginsedimentsandtheirdistributions.Theresultsshowthatphosphorusintidalflatsedimentsinthestudyareamainlyconsistsofinorganicphosphorousforms,involvingDP,Fe-P,Al-P,andCa-Pandorganicphosphorousforms,inwhichCa-PandOParedominantcompositions.Thisfindingindicatesthatspatialdistributionsofvariousphosphorousformsarerelatedtosedimentaryenvironmentsinwaterandgrainsizesofsediments,andareinfluencedbysewagedischargesandeffluentsfromaquacultivationinthecoastalareas.

简介：DuringtheconstructionoftheguidingdikeintheYangtzeEstuary,someofthecaissonstructuressankintothesoilfor1～5morslidabout20mawayfromtheoriginalplacewhenastrongstormattackedthisarea.Dynamictriaxialtestswerecarriedouttosimulatethebehavioroffoundationsoilsunderwaveloading.Thetestresultsshowthattheexcessivesettlementandlateralmovementofthecaissonsareduetotheweakeningofthesoftclaystrengthduringthestrongstorm.Thetestresultsalsoshowthattheabilityofthesoftclaytoresistthewaveforcewillbegreatlyincreasedwhenthesoftsoilsamplesaresuitablyimproved.Basedonthetestresults,animprovementmethodcombiningverticaldrainswithsurchargeloadingwasproposedtostrengthenthefoundationsoil.Ontheimprovedsoilfoundation,thedikehasbeenreconstructedandundergoneseveralstrongstormswithoutanydamage.Afiniteelementapproachhasbeendevelopedforanalyzingthesettlementandstabilityofthedikeundertheactionofstrongstorm.

简介：Basedonthe2-DflowandsedimentnumericalmodeloftheYangtzeEstuaryandtheHangzhouBay,thecharacteristicsofwaterandsedimentexchangeintheirjointwatersisstudiedthroughquantitativecalculationandanalysisofthecharacteristicsofwaterflowandsedimenttransportation.Theresultsshowthatthereisperiodicalwaterandsedimentexchangeinthisjointwaters,thatthenetwaterexchangeappearsmainlybetween0～6mdepth(theoreticaldatumplane,thesamebelow)offshoreandthemaximumisnearthedepthof2m,andthatthenetsedimentexchangemainlyappearsbetween0～5mdepthandthemaximumisnearthedepthof3m,indicatingthattherangeofwaterflowpassageisdifferentfromthatofsedimenttransportfromtheYangtzeEstuarytotheHangzhouBay.Combinedwiththeresultsofnumericalsimulation,thispaperalsoanalyzesthehydrodynamicalmechanisminfluencingwaterandsedimentexchangebetweentheYangtzeEstuaryandtheHangzhouBay,includingtidalfluctuation,tidalcurrentkineticenergy,tide-inducedresidualcurrentandthetraceofwaterparticles.Finally,thesedimenttransportationpassageontheNanhuitidalflatisdiscussed,andtheresultsshowthatsedimentistransportedintotheHangzhouBayfromthesouthsideofShipilei,whilesedimentisbroughtbacktotheSouthChanneloftheYangtzeEstuaryfromthenorthside.

简介：Inordertoexaminetheeffectivenessofengineeringprotectionagainstlocalizedscourinfrontofthesouthgroin-groupoftheYangtzeEstuaryWaterwayImprovementProject,PhaseI,anundistort-edphysicalmodelonageometricscaleof1:250isbuiltinthisstudy,coveringtwogroinsandtheiradacentestuarineareas.Byuseofrinsingfix-bedmodelaswellaslocalizedmobile-bedmodel,theexperimentisundertakenunderbi-directionalsteadyflow.Accordingtotheexperimentalresults,waterwaydredgingleadstotheincreaseinsteramvelocity,theincreasebeinglargerduringtheebbthanduringtheflood.Con-structionoftheupstreamgroinhassomeinfluenceontheflowpatternsnearthedownstreamgroin.Local-izedscourinfrontofthegroin-headsiscontrolledmainlybyebbflow.Inthecaseofariverbedcomposedentirelyofsilt,thedepthsoflocalizedscourinfrontofthetwogroin-headsare27mand29m,respectively.Inreality,theunderneathsedimentoftheprototyperiverbedisclaywhosethresholdve

简介：FromJuly23rdtoAugust15th,2001,afieldcultivationexperimentwascarriedouttodeterminethelimitationfactorsofphytoplanktonintheYangtzeRiverestuaryandtheadjacentareas.TheresultsindicatedthatthepotentiallimitingnutrientwasphosphorusintheYangtzeRiverdilutedwaterarea,nitrogenintheoffshoreoftheYangtzeRiverestuaryandtheconversionofphosphorustonitrogeninthemiddlearea.Ironandsiliconwerenotthepotentiallimitingfactors.Ifthereweresomekindsoflimitingfactorsinthewater,thegrowthofphytoplanktonwouldbelimitedobviously.Incaseofdisappearanceofthelimitingfactor,thephytoplanktonwouldgrowfast.WhentheNoctilucascintiuansbloomoccurred,thephytoplanktonbiomasslevelwasverylowinashorttimeduetothegrazingpressure.Whenthegrazingpressuredisappeared,thephytoplanktonwouldgrowquicklyinabundantnutrientscondition.

简介：Withtheenhancedwarmingandacidificationofglobalocean,whetherandtowhatextentthenaturally-weatheredfluvialsedimentintotheseacanreleaseelementsandthusinfluencethegeochemicalprocessandecosystemofglobaloceanremaintoberesolved.Inthiscontribution,anexperimentalstudywascarriedouttoexaminethereleaseratesofmajorelements(Ca,K,MgandAl)fromthesurfacesedimentsintheChangjiang(YangtzeRiver)EstuaryunderthepHvaluesof4.0,6.0and7.0.Thetwostudiedsedimentsconsistprimarilyofquartz,plagioclase,calciteandclayminerals,withtheBET(Brunauer,EmmettandTeller)surfaceareasof61.7m2g-1and23.1m2g-1.MajorelementsofCa,K,MgandAlshowdifferentreleaseratesunderdifferentsolutionpHvalues.WiththedecreasingsolutionpH,thereleaseratesofCaandKincreaseobviously,whilethereleaseratesofMgandAlincreasewiththeinitialsolutionpHvaryingfrom6.0to7.0.Thedifferentreleaseratesoftheseelementsarecloselyrelatedtotheoriginalmineralcompositionofthesedimentsandthereactionkinetics.Basedontheexperimentalobservation,quartzandclaymineralsthathavelowdissolutionratesmaydominatethemajorelementreleasetotheaqueousphase.Thisstudyrevealsthattheenhancingoceanacidificationcouldcauseconsiderablereleaseofmajorelementsfromnaturalterrigenoussedimentsintotheambientmarineenvironment,whichhastobeconsideredcarefullyinthefuturestudyonglobalchange.更多还原

简介：PCBspollutantsaremeasuredontidal-flatsedimentsofYangtzeestuarybyahighresolutioncapillarycolumngaschromatography(HP6890)equippedwithan63Nielectroncapturedetector(ECD).TheconcentrationtendencyofPCBsisPhragmiteszone＞Scirpuszone＞baremudflats.TherearelinearrelationsbetweenPCBsandTOCand＞63μmgrainsizepercentage(involume).Thelowchlorinatedcongenersmaybemoreimportantthanthehighchlorinatedcongenersinthisarea.PCBsprefertoaccumulateinthesedimentsnearsewageoutletsandPhragmiteszone.Thesediments′PCBspollution(10.7～28.6ng/g,dryweight)intheYangtzeestuarytidal-flatislessseriousthanthatofthemostofotherareasintheworld.Butthedetectedratiois100%,eventheJiuduanshashoalhasdetectedPCBs,somuchattentionshouldbepaidtothisareaforPCBs.

简介：在直径的10m的一个浮标被用来在垂直侧面记录当前的速度和方向在近海Changjiang(长江)河口的区域(与46.0m的平均的水深度)为一年。结果包括：(1)水流顺时针方向旋转并且没有清楚的季节的变化，当前的方向在垂直侧面是一致的。(2)水平当前的速度通常高，与发生在夏天的128.5cm/s和出现在离表面通常靠近的冬季的105.5cm/s的最大值。在在一样的垂直侧面秋天的平均当前的速度变化(差别是不到8.0cm/s)，与发生在夏天的47.0cm/s和在冬季的40.8cm/s的最大值。平均当前的速度在春天潮期间是两次那在小潮潮(26.5cm/s)期间。(3)速度的重要差别在垂直侧面被观察。最大的当前的速度发生在任何一个表面(春天和冬季)或表面下(夏天和秋天)，以出现在底部的最小的当前的速度。所有层的最大的平均当前的速度是57.9cm/s，它在夏天期间发生在18-m层。(4)剩余水流的平均速度从7.5cm/s到11.3cm/s，与在春天的最强壮的发生并且在冬季最弱。所有层的剩余水流在春天和冬季期间是东方的，而向东北或向北方在夏天和秋天期间。(5)水流在Changjiang河口近海被冲淡的Changjiang河分泌物，台湾温暖的水流，季风和潮一起影响。

简介：Stiffnessdegradationwilloccurduetothegenerationofaccumulatedporepressureinsaturatedsoftclaysundercyclicloading.Thesoilstatic-dynamicmulti-purposetriaxialandtorsionalshearapparatusinDalianUniversityofTechnologywasemployedtoperformdifferenttypesoftestonthesaturatedsoftmarineclayintheYangtzeEstuary.Undisturbedsamplesoftheclayweresubjectedtoundrainedcyclicverticalandtorsionalcouplingshearandcyclictorsionalshearafterthree-directionalanisotropicconsolidationwithdifferentinitialconsolidationparameters.Investigatedweretheeffectsoftheinitialorientationangleofthemajorprincipalstress,initialratioofdeviatoricstress,initialcoefficientofintermediateprincipalstressandcontinuousrotationofprincipalstressaxesonthestiffnessdegradation.Itisfoundthatthedegradationindexdecreases(ordegradationdegreeincreases)significantlywithincreasinginitialorientationangleofthemajorprincipalstressandinitialratioofdeviatoricstress.Comparedwiththeeffectsoftheinitialorientationangleofthemajorprincipalstressandinitialratioofdeviatoricstress,theeffectofinitialcoefficientofintermediateprincipalstressislessevidentandthistrendismoreclearlyreflectedbytheresultsofthecyclictorsionalshearteststhanthoseofthecycliccouplingsheartests.Atthesamecyclenumber,thedegradationindexobtainedfromthecyclictorsionalsheartestishigherthanthatfromthecycliccouplingsheartest.Themainreasonisthatthecontinuousrotationinprincipalstressdirectionsduringcycliccouplingsheardamagestheoriginalstructureofthesoilmorethanthecyclictorsionalsheardoes.Basedonaseriesofexperiments,amathematicalmodelforstiffnessdegradationisproposedandtherelevantparametersaredetermined.

简介：Typhoon-generatedwavesaresimulatedwithtwonumericalwavemodels,theSWANmodelforthecoastalandYangtzeEstuarydomain,nestedwithintheWAVEWATCHIII(WW3)forthebasin-scaleEastChinaSeadomain.TyphoonNo.8114ischosenbecauseitwasverystrong,andgeneratedhighwavesintheEstuary.WW3wasimplementedfortheEastChinaSeacoarse-resolutioncomputationaldomain,tosimulatethewavesoveralargespatialscaleandprovideboundaryconditionsforSWANmodelsimulations,implementedonafine-resolutionnesteddomainfortheYangtzeEstuaryarea.TheTakahashiwindmodelisappliedtothesimulationoftheEastChinaSeascale(3-hourly)andYangtzeEstuaryscale(1-hourly)winds.SimulationsofsignificantwaveheightsintheEastChinaSeashowthatthehighestwavesareontherightsideofthestormtrack,andmaximatendtooccurattheeasterndeep-wateropenboundaryoftheYangtzeEstuary.IntheYangtzeEstuary,incomingswellisdominantoverlocallygeneratedwavesbeforethetyphoonapproachestheEstuary.AsthetyphoonapproachestheEstuary,windwavesandswellcoexist,andthewavedirectionismainlyinfluencedbytheswelldirectionandthecomplextopography.

简介：InordertodiscussthecontentdistributionsandfluxesofheavymetalsinsuspendedmattersduringatidalcycleintheturbiditymaximumaroundtheChangjiang(Yangtze)Estuary,thecontentsofheavymetals(Zn,Pb,Cd,CoandNi)havebeenanalyzed.Duringatidalcycle,theaveragecontentsofheavymetalsareintheorderofZn>Ni>Pb>CoàCd.Theaveragecontentsinebbtidearegenerallyhigherthanthatinfloodtide.However,attheinshoreSta.11,influencedbythecontaminationfromthenearbywastetreatmentplant,theaveragecontentsofZnandNiinfloodtidearehigherthanthoseinebbtideandattheoffshoreSta.10,thecontentofCdinfloodtidehigherthanthatinebbtideduetomarine-derivedmaterials.Thefiveheavymetals,mainlyterrigenous,aretransportedtowardseast-northeast,andsettledownwithsuspendedmattersintheareabetweenSta.11andSta.10.Influencedbymarine-derivedmaterials,thefluxvalueofCddoesnotaltersignificantlywithobviouslychanginginfluxdirectiontowardsnorthwest.Thesourceofheavymetals,thesalinityofwaterandtheconcentrationofsuspendedmattersarethemainfactorscontrollingthecontentdistributionsofheavymetalsduringatidalcycle.Thereisapositivecorrelationbetweenthecontentsofheavymetals(Zn,Pb,CoandNi)andthesalinityofwater,whiletheoppositecorrelationbetweenthecontentsandtheconcentrationsofsuspendedmatters.Becauseofmarine-derivedmaterials,thecontentofCdisnotcorrelatedwiththeconcentrationofsuspendedmattersandthesalinityofwater.

简介：RecentbathymetricchangesintheChangjiangEstuaryundertheinfluenceofartificialregulationengineeringsandbasinreservoirshavebeenanalyzedbasedonthemaritimechartssince1997andrecentfieldworks.Theresultsindicateaslighterosionofthechannelsintheupperandmiddleestuary,continuingdepositionandseawardmoveofthemouthbarcrestandintensifyingerosionatthenearshoreseabed.Itisnoteworthythatthemorphologicalevolutioncausedbyintensivehumanactivitiesdominatesoverthechangesfromnatureprocess.First,theriverbesareerodedoverallintheSouthBranch(SB),theSouthChannel(SC)andtheupperandmiddlereachesoftheNorthChannel(NC).Thenearshoreseabedoutsidetherivermouthisbeingerodedslightly,whichisattributedtothedecliningsedimentsupplyfromtheChangjiangBasinduetotheconstructionoftheThreeGorgesDamupstream.Thesedimentabovetheseabedisveryactiveandcoarsened,meanwhile,sandwavesarebecomingmoredistinct.Second,adepositionoccursintheNorthBrach(NB),themouthoftheNC,themouthbarsoftheNorthPassage(NP)andtheSouthPassage(SP)andespeciallythemainchanneloftheNP,whereitshowsamassivesiltationafterthedeepwaterwayproject.Thereasonsfortherecentchangesarenotonlythedynamicstructureinestuarinemouthbars,butalsothesupplyofsedimentresuspensioninalocalandoffshorearea.Meanwhile,thesevereerosionandsiltationinsomereachesisrelatedtotheconstructionofestuarineengineerings.ItisindicatedthattheChangjiangEstuaryisgraduallyself-adjustedandadaptingtothevaryingnaturalfactorsandintensivehumanactivities.Thestudyonthemechanismofself-regulationoftherecentbathymetricchangesintheChangjiangEstuaryhasimportantandpracticalsignificance.

简介：从Changjiang河(长江)河口，Hangzhou海湾，和他们的邻近的水的表面沉积为他们的谷物尺寸分发，器官的碳(OC)集中，和稳定的碳同位素作文被分析(13C)。把分析基于这，大约36件表面沉积样品从各种各样的环境被选择并且分开了成沙(>0.250公里，0.1250.250公里，0.0630.125公里)并且淤泥(0.0250.063公里)由湿筛的分别方法的部分，并且推进进淤泥--(0.0040.025公里)并且泥土大小(<0.004公里)由离心的分别的部分。六个谷物尺寸范畴的沉积为他们的OC和13探索谷物的C内容在学习区域缩放沉积OC的作文和运输路径。从对粗糙的部分好，分别地，OC内容是1.18%，0.51%，0.46%，0.42%，0.99%，和0.48%当时13Cwas21.64,22.03,22.52,22.46,22.36，and22.28分别地。在每个尺寸范畴，OC贡献分别地是42.96%，26.06%，9.82%，5.75%，7.09%，和8.33%。在泥土和好淤泥部分的OC内容(<0.025公里)是大约69.02%。高OC集中主要被发现在近海在Changjiang河河口的东北，在在Changjiang河和Hangzhou海湾的更低的河口的现代沉积，并且在气旋的埃迪的现代沉积现代沉积到济州岛的西南。与13体积沉积的C显示在Changjiang河河口的陆上的器官的材料是搬运朝海的方向并且经由二条小径驱散现代沉积到气旋的埃迪到济州岛的西南：一个人是Changjiang河的结果冲淡的水(CDW)北方江苏沿海的水流和黄海沿海的水流驾驶的向东北的延长分支，当另一个是CDW的结果时台湾温暖的水流驾驶的向南方的延长分支。

简介：ViathevaluableopportunityoftheThreeGorgesReservoir(TGR)135-mfillinginJune2003,theYangtzedischargeandsuspendedsedimentconcentration(SSC)enteringtheestuaryduringtheperiodfrom15Mayto15July2003wereanalyzedtoexaminetheinstanteffectsofthefillingonthem.TheYangtzedischargeandSSCenteringtheestuaryintheperiodsbefore,duringandafterthefillingclearlyindicatedthreephases:1)thepre-storagephasecharacterizedbynaturalconditions,inwhichtheSSCincreasedwithincreasingwaterdischarge;2)thestoragephase,duringwhichtheSSCdecreaseddramaticallywithdecreasingwaterdischarge;and3)thepost-storagephase,duringwhichboththeSSCandwaterdischargeremainedatrelativelylowlevelsfirstuntiltheendofJune,thentheSSCincreasedgraduallywithincreasingwaterdischarge.ItseemsthatthetimesfortheinstanteffectsofthedecreasingdischargedownstreamfromtheupperYangtzeontheYangtzedischargeandSSCenteringtheestuaryduetotheTGR135-mfillingtotakeplacewereabout5dand1drespectively,whilebothwereabout18dforthoseoftheincreasingdischarge.Thisprobablyreflectsthebufferingandresultantlyhysteresisofthe1800-kmstretchfromtheupperYangtzetotheestuary.TheresultsarehelpfulforscientificandhydrologicalinvestigationoftheYangtzemainstreamdownstreamfromtheTGRDamandoftheestuarineandadjacentcoastalwaters.