简介：Inthepresentpaperitwillbeshownthat,bytakingthereferenceframemovingwiththevelocityoffluidattheinterlaceoftwosteadyparallelstreams,thelaminarboundarylayerflowinthetwofluidscanbedecoupledintotwoflows.Theseareexactlythesameasthelaminarboundarylayerflowsalongaflatplate.Andthat,byusingtheexistingexactsolutionofthelaminarboundarylayerequationfortheboundarylayerflowalongaflatplateandappropriateboundaryconditions.Anexactsolutionofthelaminarboundarylayerequationforthelaminarboundarylayerbetweentwoparallelstreamswithdifferentdensities,viscocitiesandvelocitiesisgivenelegantly.ForthecasesconsideredbyLock,theresultsobtainedbythepresentmethodarecomparedwithLock’snumericalcalculationsindetail.

简介：ThebiomassesoffishesatthebottomlayeroftheBohaiSeaareextimatedbyanalysingthedataonsamples(447hauls,morethan0.2millioninnumberor20tinweightoffishes)collectedmonthlybyourinstitutefromApril,1982toMay,1983byapairofbottomtrawlsthroughtheBohaiSea.Theexploitationproblemsarealsodiscussedinthispaper.

简介：Permittivityofaseafoamlayerisveryimportantininvestigatingoceanbrightnesstemperaturemodel.Atmicrowavefrequency,theRayleighmethodisdevelopedtoestimatetheeffectivepermittivityoftheseafoamlayer.TosimplifythetediouscalculationofseafoameffectivepermittivityatLband(1.4GHz),Pade’approximationisadoptedtofittheseafoameffectivepermittivitycomputedbytheRayleighmethod.Withthisfittingformula,anewbrightnesstemperaturemodelofseafoamlayerdefinedbycertaingeophysicalparameters,suchasairvolumefraction(AVF),seasurfacetemperature(SST),seasurfacesalinity(SSS)andthicknessoffoamlayerd,isgiven.Furthermore,thesensitivitiesofthebrightnesstemperaturemodeltoSST,SSS,dandAVFofaseafoamlayeratLbandarediscussed.Thesensitivitiesarerankedfrommosttoleastintheorder:(1)d;(2)AVF;(3)SSS;(4)SST.ThisresultindicatesthatthemeasurementerrorsofdandAVFhavesignificantimpactsontheretrievalsofSSSandSST.Withtheexperimentalbrightnesstemperaturedata,theSSSandAFVareretrievedbycostfunction.

简介：-Aone-layertime-invarianteddyviscositymodelisspecifiedtodevelopamathematicalmodelfordescribingtheessentialfeaturesoftheturbulentwaveboundarylayeroveraroughbed.Thefunctionalformoftheeddyviscosityisevaluatedbasedoncomputationalresultsfromatwo-equationturbulencemodelinwhichtheeddyviscosityvarieswithtimeandspace.Thepresenteddyviscositymodelsimplifiesmuchofthemathematicalcomplexityinmanyexistingmodels.Predictionsfromthepresentmodelhavebeencomparedwithawiderangeofexperimentaldata.Itisfoundthattheeddyviscositymodeladoptedinthepresentstudyisphysicallyreasonable.

简介：Theperfectlymatchedlayer(PML)isaneffectivetechniquefortruncatingunboundeddomainswithminimalspuriousreflections.Afluidparabolicequation(PE)modelapplyingPMLtechniquewaspreviouslyusedtoanalyzethesoundpropagationprobleminarange-dependentwaveguide(LuandZhu,2007).However,LuandZhuonlyconsideredastandardfluidPEtodemonstratethecapabilityofthePMLanddidnottakeimprovedone-waymodelsintoconsideration.Theyapplieda[1/1]Padéapproximanttotheparabolicequation.Thehigher-orderPEsaremoreaccuratethanstandardoneswhenaverylargeanglepropagationisconsidered.Asforrange-dependentproblems,thetechniquestohandletheverticalinterfacebetweenadjacentregionsaremainlyenergyconservingandsingle-scattering.Inthispaper,thePMLtechniqueisgeneralizedtothehigherorderelasticPE,asistothehigherorderfluidPE.Thecorrectionofenergyconservingisusedinrange-dependentwaveguides.Simulationismadeinbothacousticcasesandseismo-acousticcases.Range-independentandrange-dependentwaveguidesarebothadoptedtotesttheaccuracyandefficiencyofthismethod.ThenumericalresultsillustratethataPMLismuchmoreeffectivethananartificialabsorbinglayer(ABL)bothinacousticandseismo-acousticsoundpropagationmodeling.

简介：大旋涡模拟(LES)被用来调查形成对照的动态特征砍骚乱(圣)和在表面的兰米尔循环(LC)混合了层(SML)。圣被在SML强迫的风通常导致。LC能被包括强迫的风，波浪和旋涡的角色的波浪水流相互作用驾驶。LES结果证明LC压制水平速度并且极大地修改顺风的速度侧面，但是增加垂直速度。LC的强壮的downwelling喷气加速并且增加向下作为与圣塞相比精力搬运垂直旋涡粘性KL的m比混合的圣斯特朗的由LC导致的大得多有二个地点。他们位于2s3s(司烧深度规模)并且SML的更低的层分别地。它的价值和位置随着时间周期性地变化。相反，最大的K圣导致的m位于SML的中间的深度。LC产生的狂暴的动能(TKE)由在TKE和Km是明显的。因此，LC的parameterization不能完全基于TKE。为深SML，在LC的大规模旋涡的传送对流起一个主要作用在向下，精力和LC的运输能导致更强壮的速度砍(SML底附近的S2)。另外，LC导致的大规模旋涡和S2总是正在变化，它需要充分在LC的parameterization被考虑。

简介：ThederivationofGreenfunctioninatwo-layerfluidmodelhasbeentreatedindifferentways.Inatwo-layerfluidwiththeupperlayerhavingafreesurface,thereexisttwomodesofwavespropagatingduetothefreesurfaceandtheinterface.ThispaperisconcernedwiththederivationofGreenfunctionsinthethreedimensionalcaseofastationarysourceoscillating.Thesourcepointislocatedeitherintheupperorlowerpartofatwo-layerfluidoffinitedepth.Thederivationiscarriedoutbythemethodofsingularities.Thismethodhasanadvantageinthatitinvolvesrepresentingthepotentialasasumofsingularitiesormultipolesplacedwithinanystructuresbeingpresent.Furthermore,experienceshowsthatthesystemsofequationsresultedfromusingasingularitymethodpossessexcellentconvergencecharacteristicsandonlyafewequationsareneededtoobtainaccuratenumericalresults.Validationisdonebyshowingthatthederivedtwo-layerGreenfunctioncanbereducedtothatofasinglelayeroffinitedepthorthattheupperGreenfunctioncoincideswiththatofthelower,foreachcase.Theeffectofthedensityontheinternalwavesisdemonstrated.Also,itisshownhowthesurfaceandinternalwaveamplitudesarecomparedforboththewavemodes.Thefluidinthiscaseisconsideredtobeinviscidandincompressibleandtheflowisirrotational.

简介：Verticallyexploringthecharacteristicsofthetyphoonboundarylayer(TBL)playsanimportantroleinrecognizingtyphoonstructure.TheboundarylayerradialdirectionandtangentialwindcharacteristicsofTyphoonUsagibasedontheobservationaldataofthreeboundarylayerwindprofilerstationsalongtherouteofTyphoonUsagi(No.1319)andbycombiningwithsoundingdata.Theresultsshowthat:(1)maximumtangentialwindappearsinthevicinityoftheeyeareaofUsagi,anditbasicallymaintainsaheightofaround1800mwhenUsagikeepsastrongtyphoonlevel,withtherapidlydecreasingstrengthofUsagiafteritlands,thespeedofthemaximumtangentialwindanditsverticalrangebothdecrease;(2)theheightofthemaximumtangentialwindisclosetothatoftheinflowlayertopofthetyphoon,andisgreaterthanthatoftheboundarylayerestimatedonthebasisofRichardsonnumberorpotentialtemperaturegradient,whiletheheightofmixedlayerjudgedonthebasisofthesignal-to-noiseratio(SNR)oritsgradientisusuallylow;(3)thetheboundarylayerheightcanreachhigherthan2100mbeforeUsagilands.Whenthetyphoonleveloraboveisachieved,theboundarylayerheightobservedbyvariousstationsdoesnotchangemuch,basicallystayingatbetween1200and1600m.WiththedecreasingstrengthofUsagiafteritslandfall,theboundarylayerheightrapidlydrops.

简介：SeasonalvariationandtopographyofthemixedlayerintheSeaofJapanarestudiedbycomparisonofresultsfromlong-termobservationdataanalysisandfromnumericalsimulationwiththeMHIoceanicmodel(Shapiro.1998.MarineHydrophysicalJournal,6:26～40).ThedataareretrievedfromOceanographicAtlasoftheBeringSea,OkhotskSea,andJapan/EastSea(Rostov,Rostov,Dmitrieva,etal.2003.PacificOceanography,1(1):70～72).Thesimulatedandlong-termpatternsarecompared.Animpactofsurfacebuoyancyflux,wind,andconvergence/divergenceofsurfacecurrentsuponthemixedlayerintheSeaofJapanisanalyzed.

简介：Almosthalfoftheoceanicwatercolumnsexhibitdouble-diffusion.Theimportanceofdouble-diffusioninglobaloceans'saltandheatfluxes,water-massformationandmixing,andcirculationisincreasinglyrecognized.However,suchanimportantphysicalprocessintheoceanhasnotbeenwellstudied.Oneofthereasonsisthedifficultyofparameterizingandquantifyingtheprocesses.Thepaperpresentedhereattemptstoquantifythedouble-diffusivefluxesofsaltandheatintheocean.Previousqualitativeanalysisbyapplyingthewater-massTurnerangle,mTu,totheNorthPacificIntermediateWater(NPIW)layershowedafavorableconditionforsalt-fingeringintheupperNPIWduetotheoverlyingwarm/saltywaterabovethecold/freshNPIWcore,andadoubly-stableconditioninthelowerNPIWwherepotentialtemperaturedecreaseswithdepthwhilesalinityincreases,inducingdoublestratificationwithrespecttobothpotentialtemperatureandsalinity.Thepresentstudygivesaquantitativeestimateofdouble-diffusivefluxesofsaltandheatcontributedbysalt-fingeringintheupperNPIWlayer.

简介：OnthebasisofhydrographicdataobtainedinNovember28toDecember27,1998cruise,thecalculationofthecirculationintheSouthChinaSea(SCS)ismadebyusingtheP-vectormethod,incombinationwithSSHdatafromTOPEX/ERS-2analysis.Forstudyofthedynamicalmechanism,whichcausesthepatternofwintercirculationintheSCS,thediagnosticmodel(Yuanetal.,1982;YuanandSu,1992)isusedtosimulatenumericallythewintercirculationintheSCS.Thefollowingresultshavebeenobtained.(1)ThemaincharacteristicsofthecirculationsystemsinthecentralSCSareasfollows:AcoastalsouthwardjetinwinterispresentatthewesternboundarynearthecoastofVietnam;thereisastrongercycloniccirculationwithalargerhorizontalscaleeastofthiscoastalsouthwardjetandwestof114°E;thereisaweakeranti-cycloniccirculationinthecentralpartofeasternSCS;thereisastrongerandnortheastwardflowopposingthenortheasterlymonsoonbetweenaboveastrongercycloniccirculationandaweakeranti-cycloniccirculation.(2)ThecirculationsystemsinthenorthernSCSareasfollows:1)ThereisacycloniccirculationsystemnorthwestofLuzon,andithasthreecentersofthecoldwater;2)Thereisananti-cycloniceddy.Itscenterislocatednear(20°N,116°40′E);3)Thereisawarmandanti-cycloniccirculationsouthofHainanIsland;4)Thereisanortheastwardflow,theSouthChinaSeaWarmCurrent,inwinteroffGuangdongcoastinthenorthernSCS.(3)InthesouthernSCSthereisananti-cycloniccirculation,andalsothereisasmallerscalecoldwaterandcycloniceddy.(4)TheabovepatternofwintercirculationintheSCSagreesqualitativelywiththehorizontaldistributionoftemperatureat200mlevel.(5)Thedynamicalmechanismwhichproducestheabovebasicpatternofwintercirculationisbecauseofthefollowingtwocauses:1)Thejointeffectofthebaroclinityandrelief(JEBAR)isanessentialdynamicalcause;2)Theinteractionbetweenthewindstressandb

简介：Astructurefunctionapproachisappliedtoestimatetheturbulentkineticenergy(TKE)dissipationrateinthebottomboundarylayerofthePearlRiverEstuary(PRE).SimultaneousmeasurementswithanacousticDopplervelocimeter(ADV)suppliedindependentdatafortheverificationofthestructurefunctionmethod.Theresultsshowthat,1)thestructurefunctionapproachisreliableandsuccessfullyappliedmethodtoestimatetheTKEdissipationrate.Theobserveddissipationratesrangebetween8.3×104W/kgand4.9×106W/kginYM01andbetween3.4×104W/kgand4.8×107W/kginYM03,respectively,whileexhibitingastrongquarter-diurnalvariation.2)Thebalancebetweentheshearproductionandviscousdissipationisbetterachievedinthestraightriver.Thisfirst-orderbalanceissignificantlybrokenintheestuarybynon-shearproduction/dissipationduetowave-inducedfluctuations.

简介：AerosolsampleswerecollectedonboardtheresearchvesselXuelongduringtheFifteenthChineseAntarcticResearchExpedition(CHINAREXV)inNovember1998-April1999andtheFirstChineseArcticResearchExpeditioninJuly-September1999.TheareastraversedbytheexpeditionarycruisesincludetheArcticOcean,thewesternNorthPacificOceanandtheeasternIndianOcean,covering75°N-69°Sand75°E-133°W.AerosolsampleswerealsotakenattheChineseZhongshanStationinEastAntarcticaduringtheCHINAREXV.Analysisofthesamplesyieldedconcentrationsofnon-sea-saltsulfateandothersolublechemicalspeciesinthemarineboundarylayer.Thedatasuggestthatthechemicalcompositionofthemarineaerosolsisinfluencedbythreemajorsources:continentalairmasses,primaryoceanicemissions,andsecondarymarineaerosolsoriginatedfromoceanicemissions.Theresultsshowthat,awingtostronganthropogenicsulfuremissionsfromtheAsiancontinent,non-sea-saltsulfateconcentrationsintheNorthernHemisphere(thewesternNorthPacific)marineaerosolaresignificantlyhigherthanthoseintheSouthernHemisphere(theeasternIndianOcean).Aerosolnon-sea-saltsulfateconcentrationsappeartobeinverselycorrelatedwithaerosolnon-sea-saltchloridewhichshowssignificantlynegativevalues,indicatingthelossofchloridebyseasalts,inmostaerosolsamples.SincegaseousHClmaybeinvolvedinchemicalreactionsthatdepleteatmosphericozoneinthemarineboundarylayer(MBL),highlevelsofacidicnon-sea-salt-sulfatereleasedbyhumanactivitiesinthelowandmid-latitudesoftheNorthernHemispheremaybecomeanimportantpotentialcontributortothelossofatmosphericozoneintheMBL.

简介：

简介：Thehighstrengthlow-alloysteelsareweldedbyunderwaterwetweldingwithstainlesssteelelectrodes.Themicrostructuralandelectrochemicalcorrosionstudyofbasemetal(BM),weldzone(WZ)andheataffectedzone(HAZ)arecarriedouttounderstandtheinfluenceofthecorrosionproductlayergeneratedonthehighstrengthlow-alloysteelsweldedbyunderwaterwetweldingwithstainlesssteelelectrodes,methodsusedincluding,potentiodynamicpolarization,electrochemicalimpedancespectroscopy(EIS)andscanningelectronmicroscope(SEM).TheresultsindicatethattheWZactsasacathodeandthereisnocorrosionproductonitthroughouttheimmersionperiodinseawater.TheHAZandBMactsasanodes.ThecorrosionratesoftheHAZandBMchangewiththeimmersiontimeincreasing.Intheinitialimmersionperiod,theHAZhasthehighestcorrosionratebecauseithasacoarsetemperedmartensitestructureandtheBMexhibitesamicrostructurewithveryfinegrainsofferriteandpearlite.Afteraperiodofimmersion,theBMhasthehighestcorrosionrate.ThereasonisthatthecorrosionproductlayerontheHAZisdenseandhasabetterprotectivepropertywhilethatontheBMislooseandcannotinhibitthediffusionofoxygen.