简介:在华南海(SCS)的海条件的统计描述被分析调查一30年(1976-2005)每天数字地模仿了波浪高度和风速度数据。月刊这些参数的变化显示出那波浪高度和风速度有最小在12月分别地在5月和2.04m和8.12ms1,的山峰价值分别地0.54m和4.15ms1,珍视。高度和风速度和年度、季节、每月的吝啬的海的随后的描述基于这些说的每日的波浪的统计分析参数也是做。结果出现那一般来说,细微的海国家在SCS占优势并且将近在所有季节和月有最高的出现。当时,中等的海条件在12月和1月的冬季月内占优势光滑(小浪)海状态在5月占优势。而且,海状态的空间变化显示出那平静并且平静的海面条件在南部的SCS有高出现(25%-80%)。细微的海条件在SCS的大多数部分上显示出最大的出现(25%-55%)。不平、很不平的海的高出现(8%-17%)在中央SCS在一些区域上散布。到非凡的条件的从高度的海状态显示出稀罕出现(<12%)在北SCS。平静(玻璃质)海状况不在SCS显示出出现。
简介:Recentandpaleo-submarinelandslidesarewidelydistributedwithinstrataindeep-waterareasalongcontinentalslopes,uplifts,andcarbonateplatformsonthenorthcontinentalmarginoftheSouthChinaSea(SCS).Inthispaper,high-resolution3Dseismicdataandmultibeamdatabasedonseismicsedimentologyandgeomorphologyareemployedtoassistinidentifyingsubmarinelandslides.Inaddition,depositionmodelsareproposedthatarebasedonspecificgeologicalstructuresandfeatures,andwhichillustratethelocalstressfieldoverentiresubmarinelandslidesindeep-waterareasoftheSCS.TheSCSisoneofthelargestfluvialsedimentsinksinenclosedorsemi-enclosedmarginalseasworldwide.Itthereforeprovidesasetofpreconditionsfortheformationofsubmarinelandslides,includingrapidsedimentaccumulation,formationofgashydrates,andfluidoverpressure.Anewconceptinvolvingtemporalandspatialanalysesistestedtoconstructarelationshipbetweensubmarinelandslidesanddifferenttimescaletriggermechanisms,andthreemechanismsarediscussedinthecontextofspatialscaleandtemporalfrequency:evolutionofslopegradientandoverpressure,globalenvironmentalchanges,andtectonicevents.Submarinelandslidesthataretriggeredbytectoniceventsarethelargestbutoccurlessfrequently,whilesubmarinelandslidestriggeredbythecombinationofslopegradientandoverpressureevolutionarethesmallestbutmostfrequentlyoccurringevents.Insummary,analysisshowsthattheformationofsubmarinelandslidesisacomplexprocessinvolvingtheoperationofdifferentfactorsonvarioustimescales.
简介:Basedupontheone-yearwindwavemeasurementdata,collectedfromtheSouthChinaSea(SCS)atcoordinates20°36.298?N,110°45.433?E.byAcousticWaveAndCurrent(AWAC),weanalyzedthewavecharacteristicsandconcludedthatthemostcommonwavedirectionwasEandthesecondmostcommondirectionwasENE,themeanandthemaximumvaluesofsignificantheightwas1.2mand4.36m,respectively.Themeanperiodwas4.0s.Wealsoevaluatedthewavespectrumsunderconditionsexistinginthreetyphoons:Rumbi,JetiandUtor.Wefoundthatunimodalspectrumsoccurredmoreoftenthanothers,andthemaximumspectrumpeakwas30.7911m2s.Theminimumpeakfrequencywas0.0625Hz,andthemeanpeakfrequencywas0.126Hz.Thewaveperiodisimportantforthedesignofmarinestructures,especiallythepositionofpeakfrequencyhadagreatinfluenceonthestresscalculation.Spectralanalysisshowedthatthevaluesofpeakfrequencydistributedbetween0.063Hzand0.217Hz,withthemeanvalue0.114Hz.Wefitthenormalizedspectrumwith6theoreticalspectralmodels,outofwhich,theWenspectrum,JONSWAPspectrumandWallopsspectrumwereprovedtogivethebestfit.WhatdistinguishedtheWenSpectrumfromtherestwasthatitdoesnotrelyonthemeasuredspectrumforparameterestimation.Hence,werecommendthattheWenspectrumshouldbewidelyusedinmarineconstruction.
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:Integratedstudiesofverticalsedimentarysequences,grainsizes,andbenthicforaminiferaandostracoda,incombinationwithAMS14Cdating,and210Pband137CsanalysiswerecarriedoutinthreevibracorestakenfromtheareaofrelictdepositsonthewesternSouthYellowSea.Therelictsands,whichareabout0.4mthick,overlieontheEarlyHolocenecoastalmarshortidalflatdepositswithanevidenterosionalinterfaceinbetween.Themiddleandupperpartsorsometimesthewholeoftherelictsandshavebeenreworkedunderthemoderndynamicenvironment.Thesedimentationratevariesbetween0.20–0.30cmyear-1.Therelictsandsshowabimodalgrain-sizedistributionpatterninfrequencycurves,withasharppeakinthecoarsefractionbetween3Φand4Φandasecondarypeakinthefinefractionofabout7Φ.Ofthebenthicforaminiferalandostracodassemblages,thereworkedrelictsandsarecharacterizedbythemixingofthenearshoreeuryhalineshallow-waterspeciesanddeeperwaterspecies.TheerosionalinterfaceatthebottomoftherelictsandsisconsideredasaregionalravinementsurfaceformedduringthetransgressionintheEarlyHoloceneduetoshorefaceretreatinglandwards.Therelictsandswereaccumulatedontheravinementsurfaceduringthetransgressioninthedeglaciationperiodaslagdepositsafterwinnowingandreworkingbymarinedynamicprocesses.Andthesecondarypeakoffinefractioninthefrequencycurvefortherelictsandssuggeststheinputoffine-grainedsedimentsduringthereworkingprocess.Astheconclusion,therelictsandsinthestudyareaareinterpretedasatypeofreworkedrelictsediments.
简介:由于山论的阻塞,弱风醒来在华南海发生在夏天离开东北越南。在风下面醒来,温暖的水从两个高分辨率的卫星数据和水道学的观察被观察。温暖的水的wake在6月形成,继续在7月和8月成熟,开始在9月腐烂,并且消失在10月。温暖的水也弄醒表演柔韧日报它在日子期间加强并且在夜里变弱的变化。温暖的水醒来能通过导致风的混合被产生并且热(潜伏的热流动)过程。在这份报纸,一个混合的层模型被用来分别地在季节、日报的timescales上评估二个过程的相对重要性。结果比导致风的混合在季节的timescale上处理的证明热过程做更大的贡献到wake,当时温暖的水醒来被导致风的混合统治过程在上一日报timescale。
简介:Thediffusionattenuationcoefficientfordownwellingirradiance,Kd(490),isanimportantopticalparameterofseawater.Theopticalproperty,Kd(490),aroundNanshaIslandsintheSouthChinaSeawasanalyzedbasedonopticaldataprofilesmeasuredwithSPMR(SeaWiFSProfilingMultichannelRadiometer)andSMSR(SeaWiFSMuitichannelSurfaceReference)instrumentinAprilandMay,1999.TheresultsshowthatKd(490)iscloselycorrelatedwithchlorophyll-aconcentration,Cchl.a,andthattheverticaldistributionofKd(490)showsthestrongstratificationofthewatercolumninthisarea.Kd(490)hasasimilarverticalco-variationasKL(490),thediffusiveattenuationcoefficientforupwellingradiance.Bothcoefficientsincreasewithdepthintheupperlayer,whereKL(490)isgreaterthanKd(490);andafteradepth,approximativelyatthechlorophyllmaximum,theydecreasewithdepth,withtheformerbeingsmallerthanthelatter.
简介:AnalternativeindexfortheonsetofsummermonsoonovertheSouthChinaSea(SCS)hasbeendesignedbasedonthereanalysisdataoftheNationalCentersforEnvironmentalPrediction-NationalCenterforAtmosphericResearch(NCEP/NCAR).ItisfoundthatthedifferencebetweenthegeopotentialthicknessoverGuangzhouandManilacanbeusedasanalternativeindexfortheonsetofsummermonsoonovertheSCS.SincetheconvectiveheatingaltersthegeopotentialheightandthedistancebetweenGuangzhouandManilaisofsynopticscaleinthegeostraphicframework,theindexcanrepresentthestrengthofheatingandthefirstbarocliniccellovertheSCS.Bycomparisonbetweendifferentindices,itisfoundthatthesummermonsoononsetovertheSCScanbeascertainedbytheverticalzonalwindshearbetween200hPaand850hPa,thezonalwindat850hPa,theOLRanomaly,andthealternativeindexdefinedinthepresentpaper.Themeridionalwindshearbetween200hPaand850hPaalwaysappearsovertheSCSmuchearlierthanthezonalwindshearandcannotbeusedasanindexunderconsideration.
简介:Thecompositionofdetritalmineralswithgradesof0.063-0.25mminthesuperficialsedimentofSouthYellowSeaismainlystudiedinthepaper.Theresearchresultshowsthatthemineralscanbedividedintomorethanfiftysorts.Thelightmineralsaremainlyfeldspar,quartz,mica,etc.Theheavymineralsaremainlycomposedofamphibole,epidote,mica,autogenypyrite,magnetite,hematite,garnet,zirconandsoon,whichmainlydistributeinthesedimentsofsiltyclayandlutaceoussilt.Accordingtothecontentanddistributionofthemainminerals,theresearchareaisdividedintofivemiteralcombinationprovinces.Theassembledtypesofmineralsineveryprovincehavecloserelationshipwithitshydrodynamicconditionsandsedimentaryenvironment.Andthesortsofdetritalmineralsalsoshowthatthedetritalsubstancesinthesedimentaryareasmainlyoriginatefromthedrainageareasofrivers,bedrockweathering,andtransformedsediment,etc.
简介:ThemeasurementsbyusingADCP(500KH)andCTDweremadeduringAugust2000inthesouth(37°55'N,120°25'E)oftheBohaiSea,wherethewaterdepthwasabout16.5m.Thedataofhorizontalvelocitywithsamplingintervalof2minin7layerswereobtained.Thepowerspectrumanalysisofthesedataindicatesthatthereareveryenergeticinfragravitywaveswithaperiodofabout6min.Thecoherencespectrumanalysisandtheanalysisoftemporalvariationofshearshowthattheseinfragravitywavesaremainlythefreewavemodel(propertiesofedgewaves),inthemeantimetheypossesssomecharacteristicsofinternalwaves,whicharelikelyduetothedistinctivemarineenvironmentinthisarea.Itisspeculatedonthattheinstabilityprocesses(chieflyshearinstability)ofshearedstratifiedtidalflowowingtotheeffectofsea-floorslopeinthecoastalareamightbethemainmechanismgeneratingtheseinfragravitywaves.
简介:SubmarinelandslideshavebeenobservedintheBaiyunDepressionoftheSouthChinaSea.Theoccurrenceofhydratesbelowtheselandslidesindicatesthattheseslopeinstabilitiesmaybecloselyrelatedtothemassivereleaseofmethane.Inthisstudy,weusedasimpleMonte-Carlomodeltodeterminethefirst-orderdeformationpatternofagravitationallydestabilizingslope.Theresultsshowthatastressconcentrationoccursduetohydratedissociationonthenearbyglidesurfaceandontopofagaschimneystructure.Uponthedissolutionofthegashydrate,slopefailureoccursduetotheexcessporepressuregeneratedbythedissociationofthegashydrates.Whengashydratesdissociateatshallowdepths,theexcessporepressuregeneratedcanbegreaterthanthetotalstressactingatthosepoints,alongwiththeforcesthatresistsliding.Initially,thefailureoccursatthetoeoftheslope,thenextendstotheinterior.Althoughourinvestigationfocusedonlyonthecontributionofhydratedecompositiontosubmarinelandslide,thisprocessisalsoaffectedbyboththeslopematerialpropertiesandtopography.
简介:Maenggol隧道和Uldolmok海峡,在朝鲜的西南海岸上定位了,由于潮汐的效果并且到本地地质的因素有尤其是强壮、复杂的水流。在这些区域,电力用强壮的潮汐的水流,其速度在春天潮期间是超过3m/s被产生了。这个区域也为航行提供一条捷径。这些潮汐的条件有时因此是有用的,但是可以也引起可怕的事故或严重经济损坏,当关于海洋条件的精确信息不在时。在2014年4月,旅客渡船MVSewol在Maenggol隧道倾覆了,与杀死的295位旅客一起并且9仍然失踪。当这是时无疑地一人造灾难,强壮的水流是作出贡献的原因之一。给强壮的当前的速度的营救操作,和潮将转弯的时间的精确预言极其因此被需要,对行为配套的水呼吸器潜水也困难。在这研究,我们使用了与许多小岛在如此的区域为强壮的潮汐的水流的分析和模拟预报KOOS(朝鲜运作的海洋学的系统)的系统的高分辨率的沿海的发行量,使用大小并且从这个研究区域当模特儿。为潮汐的水流的精确预言,小格子建模尺寸被需要,并且在这学习我们识别了提供效率以及精确性的一种合适的格子尺寸。
简介:Thepre-EocenehistoryoftheregionaroundthepresentSouthChinaSeaisnotwellknown.Newmulti-channelseismicprofilesprovidevaluableinsightsintotheprobableMesozoichistoryofthisregion.Detailedstructuralandstratigraphicinterpretationsofthemulti-channelseismicprofiles,calibratedwithrelevantdrillinganddredgingdata,showmajorMesozoicstructuralfeatures.AstructuralrestorationwasdonetoremovetheCenozoictectonicinfluenceandcalculatetheMesozoictectoniccompressionratios.Theresultsindicatethattwogroupsofcompressivestresswithdiametricallyoppositeorientations,S(S)E–N(N)WandN(N)W–S(S)E,wereactiveduringtheMesozoic.Thecompressionratiovaluesgraduallydecreasefromnorthtosouthandfromwesttoeastineachstressorientation.Thephenomenamayberelatedtotheopeningoftheproto-SouthChinaSea(thenlocatedinsouthoftheNanshablock)andtherateatwhichtheNanshablockdriftednorthwardinthelateJurassictolateCretaceous.TheNanshablockdriftednorthwarduntilitcollidedandsuturedwiththesouthernChinamargin.TheopeningofthepresentSouthChinaSeamayberelatedtothissuturezone,whichwasatectoniczoneofweakness.
简介:Withprocessingandinterpretationof25000kmfull-coveragemultibeamswathdatafromtheeasternSouthChinaSea,itisfoundthatNE-trendingandNW-trendinglinearmorphologicalfeaturessuchasscarps,horstsandgrabens,govemthecentralpart(14°~17°N)ofeasternsubbasin.Comparedwithreflectionseismicprofiles,theseNE-trendinglinearmorpho-structuresareconsideredtobetherepresentationofbasementstructuresonseabedandcanbedividedintothreelinearstructuralzones.ThetrendofthecentralzoneisNE45°~50°occurringaroundextinctspreadingcenter,thetrendofthesecondzoneisNE70°~78°onbothsidesofthecentraloneandthetrendofthethirdzoneisaboutNE60°justonthenorthofthesecondone.ThesethreeNE-trendinglinearzonesareformedinlate-stageNW-SE-trendingseafloorspreadingoftheeasternsubbasinalongNW-trendinglinearfaults,andrespectivelycorrespondtothreespreadingepisodes:17.0~19.0Ma(5d-5e),19.0~21.0Ma(5e-6a)and21.0~24.2Ma(6a-6c)basedonthecontrastofmorpho-structurestomagneticlineationanomalies.
简介:根据为系统(ROMS)建模的地区性的海洋,在华南海(SCS)的thermocline的季节的变化数字地被调查。模仿的水动力学根据以前的研究:在SCS的发行量模式在冬季是气旋的并且在夏天,和如此的一个变化逆旋风被季风风主要驾驶。在巡航获得的建模的温度侧面和观察之间的错误在海洋的上面的层是相当小的,显示海洋地位相当被模仿。根据垂直温度侧面的形状,五种thermocline类型(浅thermocline,深thermocline,混合thermocline,两倍thermocline,和多重thermocline)此处被定义。在冬季,什么时候在东北,季风占优势,在SCS的西北的很浅的架海很好被混合,并且没有明显的thermocline。深区域通常有深thermocline,并且混合或双的thermocline经常在SCS的南方在冷旋涡附近发生在区域。在夏天,当西南的季风占优势时,有浅thermocline的架海区域极大地膨胀。不同thermocline类型的分发与海洋深测术显示出一种关系:从对深水浅,thermocline类型通常变化从对浅或混合深,thermocline,和双或多重的thermocline通常发生在陡峭的区域。三个主要thermocline特征(上面的界限深度,厚度,和紧张)的季节的变化也被讨论。因为SCS也是热带气旋经常发生的一个区域,到在短时间规模的一个台风过程的thermocline的反应也被分析。
简介:ThepentadaverageminimumoutgoingIongwaveradiation(OLR)dataoverthenorthernSouthChinaSea(SCS)areselectedasindexestoanalyzetheintensityoftheconvectionconnectedwiththeSCSmonsoononset.StatisticanalysisdemonstratesthattheindexcanaccountfortheintensityoftheSCSmonsoonabout,atleast,75%.Asignificantnegativecorrelation(confidentlevelover90%)betweenShandong'ssummerrainfallandtheindexisfoundonlyintheperiodof24-26pentadsandlimitedtotheareaabovethedeeperwaterbasinoftheSCS(10°-20°N,110°-117.5°E).ThustheminimumOLRoverthedeeperwaterbasinduring24-26pentadscanbeusedasavaluablepredictorforthelong-leadforecastoftheprecipitation.The500hPageopotentialheightdataintheNorthernHemispherefortheperiodfrom1951to2000areusedinordertocharacterizethephysicalmechanismsinvolved.Thecompositeanomaliesofthe500hPalevelallowfortheidentificationanddetectionoftheteleconnectionoftheEastAsia-NorthAmerica(EAP)patternthatisresponsibletosomeextentfortheinterannualvariabilityoftheprecipitationofShandongProvince.Besides,theinterannualdifferencesoftheintraseasonalvariations(ISV)ofOLRandtheirnorthwardtransmissionprobablymakeacontributiontothepositionofthesubtropicalhighwhichisvitalforthesummerrainfallintheprovince.
简介:TheAndamanandNicobarIslandsareoneoftheUnionTerritoriesofIndia,locatedintheeasternpartoftheBayofBengal.In2010summer,theincrementinseasurfacewatertemperature(upto34℃)resultedinthebleachingofabout74%to77%ofcoralsintheSouthAndaman.Duringthisevent,coralspeciessuchasAcroporacerealis,A.humilis,Montiporasp.,Faviapallida,Diploastreasp.,Gonioporasp.Fungiaconcinna,Gardineroseriessp.,Poritessp.,FavitesabditaandLobophylliarobustawereseverelyaffected.ThisstudyistoassesstherecoverystatusofthereefecosystembyestimatingthepercentageofLiveCoralcover,Bleachedcoralcover,Deadcoralwithalgae,Rubble,Sandyflat,Algalassemblageandotherassociatedorganisms.Thesedimentationrate(mgcm-2d-1)andcoralcoverage(%)wereassessedduringthisstudyperiod.Theaveragesedimentationratewasrangedbetween0.27and0.89mgcm-2d-1.Theobservedpostbleachingrecoveryofcoralcoverwas21.1%atPortBlairBayand13.29%atHavelockIsland.Themortalityrateofcoralcoverduetothisbleachingwasestimatedas2.05%atPortBlairBayand9.82%atHavelockIsland.Oncetheseawatertemperatureresumedbacktothenormalcondition,mostofthecoralswerefoundrecovered.
简介:Shallowwaterflow(SWF),adisastrousgeohazardinthecontinentalmargin,hasthreateneddeepwaterdrillingoperations.Underoverpressureconditions,continualflowdeliveringunconsolidatedsandsupwardintheshallowlayerbelowtheseafloormaycauselargeandlong-lastinguncontrolledflows;theseflowsmayleadtocontrolproblemsandcausewelldamageandfoundationfailure.Eruptionsfromover-pressuredsandsmayresultinseafloorcraters,mounds,andcracks.Detailedstudiesof2D/3DseismicdatafromaslopebasinoftheSouthChinaSea(SCS)indicatedthepotentialpresenceofSWF.Itiscommonlycharacterizedbylowerelasticimpedance,ahigherVp/Vsratio,andahigherPoisson'sratiothanthatforthesurroundingsediments.AnalysisofgeologicaldataindicatedtheSWFzoneoriginatedfromadeepwaterchannelsystemwithgasbearingover-pressuredfluidflowandahighsedimentationrate.WeproposedafluidflowmodelforSWFthatclearlyidentifiesitsstressandpressurechanges.TheruptureofpreviousSWFzonescausedthefluidflowthatoccurredintheBaiyunSagofthenorthernSCS.