简介:Asimplethree-dimensionaltidalmodelisusedtoexaminetheM2tidalcurrentdistributioninanortheasternpartoftheEastChinaSea,especiallytheverticalvariationofthecurrentintheregion.ComputedM2currentiscomparedwithobservationsavailableandfoundtobeingoodagreement.Mainfeaturesofthecalculatingmethodinthisstudyare:(1)Verticalvariationofthetidalcurrentistakenasafunetionofthedepth-meanvelocity:(2)themethodisapplicabletoavarietyoftheverticaleddyviscosities;(3)ithasafineverticalresolution,especiallyneartheseabootom.So,thismethodnotonlyenablesustogetasteadystatesolutioneasilybutalsodepictseffectsofthefrictionontheverticalvariationofthecurrentmuchbetter.
简介:根据一系列重要历史的地图,即,华南海岛,Nansha岛,Zhongsha岛,Xisha岛,Yongxing岛和Shidao岛的地点地图,并且太平天国的岛(在1946由中华民国的内部的部的领土的管理部门转存),并且中华民国的管理区域地图在1948出版了,包围华南海岛的击破的线在华南代表瓷器海边界它是连接与的两个,和延期,中国的陆地边界。在当稳固的线被用来代表陆地boundarya时,击破的线被用来代表水边界的那时间,通用方法在然后国际性地被认出的地图使用了。上述观察在为在华南海区域上的国际海上的定界线是有用的华南海提供瓷器海边界的历史、科学的证据。
简介:Intertidalmarinemacroalgaeexperienceperiodicalexposuresduringlowtideduetotheirzonationaldistribution.ThedurationofsuchemersionleadstodifferentexposuresoftheplantstolightandaerialCO2,whichthenaffectthephysiologyofthemtodifferentextents.TheecophysiologicalresponsestolightandCO2wereinvestigatedduringemersionintworedalgaeGloiopeltisfurcataandGigartinaintermedia,andtwobrownalgaePetaloniafasciaandSargassumhemiphyllum,growingalongtheShantoucoastofChina.Thelight-saturatednetphotosynthesisinG.furcataandP.fasciashowedanincreasefollowedbyslightlydesiccation,whereasthatinG.intermediaandS.hemiphyllumexhibitedacontinuousdecreasewithwaterloss.Inaddition,theupper-zonatedG.furcataandP.fascia,exhibitedhigherphotosynthetictolerancetodesiccationandrequiredhigherlightleveltosaturatetheirphotosynthesisthanthelower-zonatedG.intermediaandS.hemiphyllum.Desiccationhadlesseffectondarkrespirationinthesefouralgaecomparedwithphotosynthesis.Thelight-saturatednetphotosynthesisincreasedwithincreasedCO2concentrations,beingsaturatedatCO2concentrationshigherthanthepresentatmosphericlevelinG.furcata,G.intermediaandS.hemiphyllumduringemersion.ItwasevidentthattherelativeenhancementofphotosynthesisbyelevatedCO2inthosethreealgaeincreased,thoughtheabsolutevaluesofphotosyntheticenhancementowingtoCO2increasewerereducedwhenthedesiccationstatusesbecamemoresevere.However,inthecaseofdesiccatedP.fascia(waterlossbeinggreaterthan20%),lightsaturatednetphotosynthesiswassaturatedwithcurrentambientatmosphericCO2level.ItisproposedthatincreasingatmosphericCO2willenhancethedailyphotosyntheticproductioninintertidalmacroalgaebyvariedextentsthatwererelatedtothespeciesandzonation.
简介:AbundantevidencesofhighersealevelsfromJiangsuandFujiancoastshaveprovedamarinetransgressioneventduring30–40kaBP,suggestingthattherewasastagewithhighsealevelandawarmclimatewhenicesheetsshrankintheNorthernHemisphere.Thedurationof30–40kaBPspannedaperiodinthelateMarineIsotopeStage3(MIS3)andwasinnatureaninterstadialepochduringtheLastGlacialperiodoftheQuaternary.Differentfromtheglacialperiodwithacoldclimate,thismarinetransgressionconsideredasapenultimatehighersealevelduringtheQuaternaryremainsapuzzlethatwhytheevidenceiscontrarytotheQuaternaryglacialtheory.Itisimportanttounderstandsealevelrisefortheseareassensitivelyrespondingtotheglobalchangesinthefuture.Torecognizethekeyissuesonsealevelchanges,theeustaticsealevel(H_S)wasdefinedastheglaciation-climateforcedsealevels,andtherelativesealevelchange(H_R)wasdefinedasthatasealevelrecordwaspreservedinsedimentthatexperiencedmultiplesecondaryactionsoflandandseaeffects.Onthebasisasdefinedabove,weconstructedmulti-levelmodelsofclimate-drivenglacio-eustaticchangesandland-seasystems.Byintegratingdatasetsfromeightboreholecoresandprescribingtheboundaryconditions,wesimulatedthechangesofHSandHRintheEastChinaSeaandsouthernYellowSeaareasinthelateMIS3.Themarinetransgressionstratafromtheboreholecoredatawasidentifiedatca.30mbelowpresentsealevelasaresultofthecollectiveinfluenceoficemeltingwater,neotectonicsubsidence,sedimentcompactionandterrestrialsedimentfillingsinceca.35kaago,whereasthesimulatedrelativesea-levelsturnedouttobe–26.3––29.9ma.s.l.Thesmallerrorinvolvedinthesimulationresultsof±(2.5–4.5)mdemonstratedthecredibilityoftheresults.OurresultsindicatedthatsealevelchangeinthelateMIS3wasdominatedbyglacialeffects,inwhichtheeustaticsea-levelwasbetween–19.2�
简介:AnimprovedprocedureforextractingtheradiationalS2tidefromanalyzedS2ispresentedinthispaper.Themajorimprovementisthatthenonlinearconstituentsareeliminatedfromtheanalyzedprincipalsemidiurnaltidesonthebasisofthe"credoofsmoothness"ofadmittancebeforeusingtheproceduregivenbyZetler.ThesemidiurnalradiationaiS2tidesfor42stationsalongChina’scoastsarecalculatedusingthemethodpresentedinthispaper,and,forcomparison,theresultsfromZetler’smethodarealsogiven.Inaddition,theradiationalS2tidesfor10stationsareanalyzedwiththeresponsemethod.Theresultsshowthatthemeanamplituderatio(radiationaltogravitational)is0.17,themeanphasedifference(radiationalminusgravitational)is119°forChina’scoasts.
简介:Climatologyoftheisothermallayerdepth(ILD)andthemixedlayerdepth(MLD)hasbeenproducedfromin-situtemperature-salinityobservationsintheEastChinaSea(ECS)since1925.ThemethodsappliedontheglobalareusedtocomputetheILDandtheMLDintheECSwithatemperaturecriterionΔT=0.8℃fortheILD,andadensitycriterionwithathresholdΔσθcorrespondingtofixedΔT=0.8℃fortheMLD,respectively.WiththederivedclimatologyILDandMLD,themonthlyvariationsofthebarrierlayer(BL)andthecompensationlayer(CL)intheECSareanalyzed.TheBLmainlyexistsintheshallowwaterregionoftheECSduringApril-Junewiththicknesslargerthan15m.FromDecembertonextMarch,theareaalongtheshelfbreakfromnortheastofTaiwanIslandtothenortheastECSischaracterizedbytheCL.Twokindsofmaintemperature-salinitystructuresoftheCLinthisareaaregiven.
简介:ThispaperpresentsactualityofinvestigationandstudyofthecrustalstructurecharactersofEastChinaSeaathomeandabroad.Basedonlotsofinvestigationandstudyachievementsandthedifferenceofthecrustalvelocitystructurefromwesttoeast,theEastChinaSeaisdividedintothreeparts-EastChinaSeashelfzone,OkinawaTroughzoneandRyukyuarc-trenchzone.TheEastChinaSeasheffzonemostlyhasthreevelocitylayers,i.e.,thesedimentblanketlayer(thevelocityis5.8-5.9km/s),thebasementlayer(thevelocityis6.0-6.3km/s),andthelowercrustallayer(thevelocityis6.8-7.6km/s).SotheEastChinaSeashelfzonebelongstothetypicalcontinentalcrust.TheOkinawaTroughzoneislocatedatthetransitionalbeltbetweenthecontinentalcrustandtheoceaniccrust.Itstillhasthestructuralcharactersofthecontinentalcrust,andnoformationoftheoceaniccrust,butthecrustofthecentraltroughhasbecometothinningdown.TheRyukyuarc-trenchzonebelongstothetransitionaltypecrustasawhole,buttheoceansideofthetrenchalreadybelongstotheoceaniccrust.AndthenorthwestPhilippineBasintotheeastoftheRyukyuTrenchabsolutelybelongstothetypicaloceaniccrust.
简介:Analysisofmagneticpropertiesofmarinesurfacesedimentshasbeengraduallyprovedtobeoneoftheeffectivemeansforresearchingthesourceofmarinesediments.Inthispaper,samplesfrom39sitesinLiaodongBaywerecollectedtoanalyzethemagneticcharacteristicsofthesurfacesediments.MagneticstudyindicatedthatthesurfacesedimentsoftheLiaodongBayarecharacterizedbymagnetite.InthemiddleandeasternpartandthesouthwestcorneroftheBay,themainmagneticgrainswerecoarsemulti-domainandpseudo-single-domainparticles,whileinotherareassingle-domainandpseudo-single-domainparticlesconstitutethemajority.Basedongrainsizeandenvironmentalmagnetismdata,thecontentofmagneticmineralshasapositivecorrelationwiththehydrodynamicenvironmentwhenthemagneticmineraldomainisfiner.However,thecontentofmagneticmineralsisinacomplexrelationshipwiththehydrodynamicenvironmentinthecoarsemagneticdomainofmagneticmineralsfoundincentralLiaodongBayandplacesoutsidetheFuzhouBay,implyingthatthestronghydrodynamicenvironmentacceleratesthesedimentationofcoarsemagneticminerals.Basedongeographicpatternofmagneticproperties,itcanbeinferredthatthemainprovenanceofthesurfacesedimentsoftheLiaodongBayisthesurroundingrivers,andthecomparativeanalysisindicatesthatYellowRiversubstancesmaybealsoexistinthebay.
简介:Carbonmonoxide(CO)playsasignificantroleinglobalwarmingandatmosphericchemistry.GlobaloceansarenetnaturalsourcesofatmosphericCO.COatsurfaceoceanisprimarilyproducedfromthephotochemicaldegradationofchromophoricdissolvedorganicmatter(CDOM).Inthisstudy,theeffectsofphotobleaching,temperatureandtheorigin(terrestrialormarine)ofCDOMontheapparentquantumyields(AQY)ofCOwerestudiedforseawatersamplescollectedfromJiaozhouBay.Ourresultsdemonstratthatphotobleaching,temperatureandtheoriginofCDOMstronglyaffectedtheefficiencyofCOphotoproduction.Theconcentration,absorbanceandfluorescenceofCDOMexponentiallydecreasedwithincreasinglightdose.Terrestrialriverineorganicmattercouldbemorepronetophotodegradationthanthemarinealgae-derivedone.TherelationshipsbetweenCOAQYandthedissolvedorganiccarbon-specificabsorptioncoefficientat254nmforthephotobleachingstudywerenonlinear,whereasthoseoftheoriginalsampleswerestronglylinear.Thissuggeststhat:1)terrestrialriverineCDOMwasmoreefficientthanmarinealgae-derivedCDOMforCOphotoproduction;2)aromaticandolefinicmoietiesoftheCDOMpoolwereaffectedmorestronglybydegradationprocessesthanbyaliphaticones.WatertemperatureandtheoriginofCDOMstronglyaffectedtheefficiencyofCOphotoproduction.ThephotoproductionrateofCOinautumnwasestimatedtobe31.98μmolm-2d-1andthetotalDOCphotomineralizationwasequivalentto3.25%-6.35%ofprimaryproductioninJiaozhouBay.OurresultsindicatethatCOphotochemistryincoastalareasisimportantforoceaniccarboncycle.
简介:OnthebasisofthedataofoceanographicsurveyintheEastChinaSeainfourseasonsduring1997~2000(23°30′~33°00′N,118°30′~128°E),thevariationoftotalbiomassanddietbiomassofzooplanktonandtheirspatial-temporaldistributionandrelationshipwiththefishinggroundofEngraulisjaponicusareapproachedandanalyzed.Theresultsshowthattheaveragebiomassis65.32mg/m3infourseasons,autumn(86.18mg/m3)beinggreaterthansummer(69.18mg/m3)greaterthanspring(55.67mg/m3)greaterthanwinter(50.33mg/m3).Theaveragevalueofdietzooplanktonbiomassis40.9mg/m3.Thetrendsofhorizontaldistributionbothinthetotalbiomassandthedietbiomassofzooplanktonaresimilar.Thehighbiomassregion(250~500mg/m3)isverylimited,onlyaccountingfor1%oftheinvestigationarea.SeasonalvariationofthebiomassisveryremarkableinthewestandnorthpartsofEastChinaSeacoastalwaters(29°30′N,125°E).Thehorizontaldistributionofdietzooplanktondependsontheabundancedistributionofcrustacean.ThedistributionofdietzooplanktonisrelatedtothefishinggroundofEngraulisjaponicusandthehigh-densityareaofyoungfishandlarval.Inspring,thecentralfishinggroundofEngraulisjaponicus(>100kg/h)andthehigh-densityareaofyoungfishandlarval(>100individualspernet)arelocatedatthesameplaceofhigh-density(100~250mg/m3)areaofdietzooplanktoninthemiddle-southernpartofEastChinaSeaortheedgeofitswaters.