学科分类
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34 个结果
  • 简介:CarboncycleisconnectedwiththemostimportantenvironmentalissueofGlobalChange.Asoneofthemajorcarbonreservoirs,oceansplayanimportantpartinthecarboncycle.Inrecentyears,ironseemstogiveusagoodnewsthatoceanicironfertilizationcouldstimulatebiologicalproduc-tivityasCO2sinkofhuman-producedCO2.Oceanicironfertilizationexperimentshaveverifiedthataddingironintohighnutrientlowchlorophyll(HNLC)seawaterscanincreasephytoplanktonproductionandexportorganiccarbon,andhenceincreasecarbonsinkofanthropogenicCO2,toreduceglobalwarming.Insixtydays,theexportorganiccarboncouldreach10000timesforaddingironbymodelpredictionandinsituexperiment,I.e.TheatmosphericCO2uptakeandinorganiccarbondrawdowninupperseawatersalsohavethesamemagnitude.Therefore,oceanicironfertilizationisoneofthestrate-giesforincreasingcarbonsinkofanthropogenicCO2.Thepaperisfocusedontheironfertilization,es-peciallyinsituoceanironexperimentsinorderthatthefutureresearchismoreefficient.

  • 标签: 大气 二氧化碳 铁肥 碳循环 全球变化 叶绿素
  • 简介:OnthebasisofdatacollectedintheJiaozhouBayinJuneandJuly2003,theDICdistributioninseawaterisstudied,andanaverageair-seafluxofCO2isestimated.TheresultsshowthatthecontentofDICinsidethebayismarkedlyhigherthanoutsidethebayinJune,butthecontentofDICoutsidethebayismarkedlyhigherthaninsidethebayinJuly.ThetrendofDICdistributioninsidethebayissimilar,viz.thecontentisthemaximuminthenortheast,thendecreasesgraduallytowardthewest,andthecontentistheminimuminthewest.Thetotaltrendofverticaldistributionistoincreasegraduallyfromsurfacetobottom.ThischaracteristicofDICdistributionisdeterminedbyJiaozhouBayhydrologyandthereisacloserelationbetweenDICandparticulateN,P.AverageCO2fluxacrossthesourceforatmosphericCO2inJuneandJuly,andthetotalCO2fluxfromseawaterintoatmosphereisabout740tinJuneand969tinJuly.

  • 标签: 胶州湾 二氧化碳 密度指示控制器
  • 简介:Althoughtheannualglobalsea-airCO2fluxhasbeenestimatedextensivelywithvariouswind-dependent-kparameterizations,uncertaintystillexistsintheestimates.Thesea-state-dependent-kparameterizationisexpectedtoimprovetheuncertaintyexistingintheseestimates.Inthepresentstudy,theannualglobalsea-airCO2fluxisestimatedwiththesea-state-dependent-kparameterizationproposedbyWoolf(2005),usingNOAA/NCEPreanalysiswindspeedandhindcastwavedatafrom1998to2006,andanewestimate,-2.18GtCyear-1,isobtained,whichiscomparablewithpreviousestimateswithbiochemicalmethods.Itisinterestingtonotethattheaveragedvalueofpreviousestimateswithvariouswind-dependent-kparameterizationsisalmostidenticaltothatofpreviousestimateswithbiochemicalmethodsbyvariousauthors,andthatthenewestimateisquiteconsistentwiththeseaveragedestimates.

  • 标签: 海-空界面 二氧化碳 流体 交换模式
  • 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.

  • 标签: 大型海藻 生态生理学 光合作用 带状配列 生长周期 碳循环
  • 简介:一个全球海洋碳周期模型基于海洋将军发行量模型流行音乐和改进biogeochemical模型,OCMIP-2被采用在历史上观察的大气的CO2集中和不同未来情形(叫的代表性的集中小径,或RCP)下面模仿碳周期过程。在这份报纸的RCP为第五份评价报告(AR5)在气候变化(IPCC)上跟随Intergovernmental面板的设计。模型结果证明海洋从空气吸收CO2,被吸收将在四RCP下面在第21世纪继续。由空至海的CO2流动在历史的时间期间增加了并且到达的网1.87Pg/a(由碳计算了)在2005;然而,它将在第21世纪到达山峰然后减少。海洋主要专心于CO2中间的纬度,并且在赤道区域释放CO2。然而,在南极围绕天极的水流(ACC)区域,海洋将在升起的CO2集中下面从来源改变到水池,包括RCP4.5,RCP6.0,和RCP8.5。在2100,人为的碳将被搬运到40摥漠敶?桴?湥楴敲礠慥?獩爠畯桧祬?呼??湡?桴?潲敬漠???獩琠敨猠慭汬獥t

  • 标签: 历史模拟 pH值 碳循环模型 生物地球化学模型 全球海洋 南极绕极流
  • 简介:光谱影像包含有丰富的地物类别信息,但由于受分类方法等因素的限制,这些信息并不能得到充分的挖掘.组合分类器由于可以实现各分类结果信息的互补,因而总有着较各单分类器效果更好的分类性能.将组合分类方法引入到光谱影像的分类实践中,并对组合的关键问题一组合规则进行探讨,提出了混合组合规则的概念.实验表明,利用该组合分类方法对光谱影像进行分类,可以得到良好的处理结果.

  • 标签: 高光谱 分类 分类器 组合
  • 简介:给出了通过平均海面模型计算海面梯度的具体方法,选择DTU13、CNES_CLS15、WHU20133种模型计算了不同海域近岸比较点海面梯度值,随机选择的30个近岸比较点处的计算结果表明:使用3种模型计算得到的海面梯度值之间的标准差均值为0.19cm/km。在卫星高度计定标的具体应用中,由海面梯度得到的海面高差改正量的误差应不超过0.3cm。

  • 标签: 卫星测高 绝对定标 海面高梯度 平均海面高模型 海面高差
  • 简介:首先给出了两种瞬时海面模型并进行了精度分析。通过模拟定位,验证了这两种模型在地球同步卫星定位应用中的可行性。最后讨论了这两种模型在地球同步卫星定位中的应用前景,指出了进一步提高这两种模型精度的关键。

  • 标签: 大地水准面 海面地形 平均海平面 潮汐 波浪 地球同步卫星定位
  • 简介:采用载波无几何组合和星间单差无电离层组合的历元间次差作为周跳检验量,因组合观测值中不包含伪距,其理论噪声与波长相比几乎可以忽略。利用两种组合观测值联合进行周跳探测,可避免各自的探测盲点。将两个载波组合联立进行周跳的求解,由于组合噪声较小,直接取整即可求得周跳的大小。提出的方法在一定程度上克服了传统周跳探测与修复算法中,由于引入伪距带来的探测能力不强、修复精度不高等问题。通过对IGS站观测数据模拟周跳探测与修复情况的统计,新提出算法的周跳探测成功率为99%,周跳修复成功率为94%。

  • 标签: GPS 周跳 高次差法 载波无几何组合 无电离层组合
  • 简介:通过实地考察和资料分析,海南岛南部全新世以来以沉降活动为主要特征,鹿回头珊瑚礁能够反映全新世以来的海平面变化,鹿回头岸礁礁坪面上的原生珊瑚礁是全新世海平面时期的产物。全新世以来南海北部至少存在过4期相对海平面阶段:7300-6000、4800-4700、4300-4200和3100-2900cal.aBP。其中7300-6000aBP是整个全新世最高海平面时期,也是鹿回头珊瑚礁发育的繁盛期,基本形成了现代珊瑚礁的地貌格局,后来不同时期发育的珊瑚礁是在此时期形成的礁塘或礁坑等低洼地中形成,并在鹿回头半岛两侧向外发展,现代珊瑚礁则发育于全新世珊瑚礁的外礁坪和礁前斜坡带。另外,鹿回头珊瑚礁反映的南海北部全新世海平面时间与南海其他地区海平面时间可以衔接或对应,说明南海地区全新世海平面具有全球背景,至少在南海是一致的,且与气候变暖紧密相联。

  • 标签: 珊瑚礁 高海平面 全新世 海南岛鹿回头
  • 简介:提出了一种基于多分辨率小波高频特征系数的光谱遥感影像亚像素目标识别方法.首先利用多尺度小波变换将光谱信号分解为不同尺度的高频特征信号,然后借助接收操作特性曲线(ROC)和马氏距离投影寻踪求取一维最佳识别特征,最后通过高斯最大似然决策函数求解亚像素目标的存在概率.通过38种小波函数的光谱数据实验证明,该方法对亚像素目标的识别效果较好.

  • 标签: 多尺度小波特征 接收操作特性曲线 投影寻踪 高斯最大似然决策函数
  • 简介:Multi-beamSonarandSide-scanSonarcompensateeachother.Inordertofullyutilizeallinformation,itisnecessarytofusetwokindsofimageanddata.Andtheimageco-registrationisanimportantandcomplicatedjobbeforefusion.Thispapersuggestscombiningbathymetricdatawithintensityimage,obtainingthecharacteristicpointsthroughtheminimalanglesoflines,andthendecidingthecorrespondingimagepointsbythemaximalcorrelatecoefficientinsearchingspace.Finally,thesecondorderpolynomialisappliedtothedeformationmodel.Aftertheimageshavebeenco-registered,Waveletisusedtofusetheimages.Itisshownthatthisalgorithmcanbeusedintheflatseafloorortheisotropicseabed.Verificationismadeinthepaperwiththeobserveddata.

  • 标签: 声纳图像 图像融合 数据处理 海洋测深数据 海底 侧向扫描声纳
  • 简介:Thecurrentadvancesinthestudyofgeochemistryandpaleo-oceanographyoftheCo-richcrustarereviewedinthispaper.WesummarizethestudyofgeochemistryoftheCo-richcrust,discussthediffusionofelementsintheCo-richcrustandtheexchangewithambientseawater.Besides,wediscusstheeffectofphosphatizationandsubstraterocksonthecompositionoftheCo-richcrust.Wealsointroducetheapplicationofstableisotopes(includingthestableisotopesofPb,Nd,andHf),radioactiveisotopes(includingtheradioactiveisotopesofBe,UandTh),andelements(includingthemajorelements,minorelementsandrareearthelements)tothestudyofpaleo-oceanographyoftheCo-richcrust.

  • 标签: Co-rich crust geochemistry paleo-oceanography ADVANCE
  • 简介:完全的mitochondrial细胞色素氧化酶子单元II(COII)基因ofPenaeinae虾Fenneropenaeuschinensis被克隆并且定序。基因为229氨酸是在长度和代码的688bp。它显示出83.2%,87.0%和83.8%顺序类似到Marsupenaeusjaponicus,Penaeus单音穿上并且Farfantepenaeusnotialis分别地。在鳕鱼ons的第三个位置的整个基因和那的A+T内容分别地是64.7%和78.2%。在F之间的种系发生的关系。chinensis和代表类Farfanatepenaeus,Marsupenaeus和Penaeus的三另外的种被分析。结果证明在四taxaranged从之中的基因距离0.1440~0.2005,超过与COI和部分16SrRNA基因估计的那些在Marsupenaeus,Litopenaeus和Melicertus之中定序,并且因此比在潜水艇类之中的价值大。COII基因比COI基因和部分16SrRNA基因的有更快的进化的率,这被建议了并且能在类或种水平被用于种系发生的分析。现在的学习的结果显示Farfantepenaeus,Fenneropenaeus,Marsupenaeus和Penaeus比亚属在更高种系发生的水平,它支持四个潜水艇类的种系发生的地位的举起的意见到类水平。

  • 标签: 中国对虾 线粒体COⅡ基因 完整序列 系统发生分析 标记物
  • 简介:Thegrowth,biochemicalcontentandbioaccumulationquantityof2,2’,4,4’-tetrabromodiphenylether(BDE-47)inSkeletonemacostatumwerestudiedunderdifferentN:Pratios(1,4,16,64and128).AllcellularbiochemicalcontentsofS.costatumpresenteddecreasingtrendovercultivationtime.Atearlystageofcultivation,thecellularprotein,carbohydrateandlipidinS.costatumpresentedhighervaluesintreatmentsofN:P=4and16.However,theywerelowerinthesetreatmentsatthelatestage,buthigherintreatmentsN:P=1and128.Similarly,BDE-47levelspercellofS.costatumwerehigherintreatmentsofN:P=4and16atearlystageofcultivation,whichwere3.8and3.7ng(106cells)-1,respectively.Atthemiddlestageofcultivation,theBDE-47levelperS.costatumcelllowered;anditfurtherreducedinthetreatmentsofN:P=4and16atthelatestagewiththevalues0.6and0.5ng(106cells)-1,respectively.However,itroseinN:P=128,reachingupto2.3ng(106cells)-1.ComparedwithBDE-47percell,BDE-47peralgalvolumeunderdifferentN:Pratiosdidnotpresentobviousdifference.ThequantityBDE-47accumulatedpercellofS.costatumwaspositivelycorrelatedwithprotein,carbohydrateandlipidpercell;meanwhile,theBDE-47pervolumehadapositivecorrelationwithbiochemicalcontentpervolume.ThevariationofbioaccumulationabilityofBDE-47inS.costatumcanbeexplainedbybiochemicalchangesduetoN:Pratios.

  • 标签: 中肋骨条藻 富集能力 施氮量 联苯醚 海洋硅藻 四溴
  • 简介:TiO2filmswereformedonmetallictitaniumsubstratesbytheanodicoxidationmethodinH2SO4solutionunderthe80VD.C..PhasecomponentandmicrostructurewerecharacterizedbyX-raydiffraction(XRD)andscanningelectronmicroscopy(SEM).Watercontactanglesontitaniumoxidefilmsurfaceweremeasuredunderbothdarkandsunlightilluminationconditions.Corrosiontestswerecarriedoutinseawaterunderdifferentilluminationconditionsbyelectrochemistryimpedancespectrum(EIS)andpolarizationcurves.TheresultshowedthattheTiO2filmpreparedbytheanodicoxidationmethodwasanatasewithauniformstructureandwithoutobviousporesorcracksonitssurface.Theaveragewatercontactangleofthefilmwas116.4?indark,incontrasttoanangleof42.7?undertheUVilluminationfor2hours,whichdemonstratesgoodhydrophobicproperty.Theanti-corrosionbehavioroftheTiO2filmwasdecliningwiththeextendedimmersiontime.Underdarkconditions,however,thehydrophobicTiO2filmretardedthewaterinfiltratingintothesubstrate.Theimpedancechangedslowlyandthecorrosioncurrentdensitywas2ordersofmagnitudelowerthanthatwiththefilmilluminatedbysunlight.AllofthosementionedaboveindicatethattheTiO2filmpossessesmuchbetterperformanceunderdarkcondition,anditcanbeappliedasanengineeringmaterialunderdarkseawaterenvironment.

  • 标签: TIO2薄膜 阳极氧化法 海水环境 腐蚀行为 二氧化钛薄膜 电化学阻抗谱
  • 简介:为弥补测高数据在近海区域因为编辑准则被剔除而导致近海测量数据质量不高的缺点,利用5参数模型的两种形式和Ice-2模型对Jason-2卫星在中国南海部分海域的海洋回波波形进行了波形重跟踪的研究,并选择20个海洋回波波形,依据最小二乘原理进行计算、分析、对比,发现5参数模型的指数形式的结果和Ice-2模型结果非常接近.研究结果表明,在开阔的海域,对Jason-2波形进行3种方法波形重跟踪时,可以优先考虑Ice-2模型.波形重跟踪技术能够提高卫星测高数据利用率,为科学研究提供可靠的数据保障.

  • 标签: 卫星测高 波形重跟踪 最小二乘法 5参数模型 Ice-2模型
  • 简介:Astochastictwo-dimensionalFornasini-Marchesini'sModelⅡ(2-DFMMⅡ)withmultiplicativenoiseisgiven,andafilteringalgorithmforthismodel,whichisoptimalinthesenseoflinearminimum-variance,isdeveloped.Thestochastic2-DFMMⅡwithmultiplicativenoisecanbereducedtoa1-Dmodel,andtheproposedoptimalfilteringalgorithmforthestochastic2-DFMMⅡwithmultiplicativenoiseisobtainedbyusingthestateestimationtheoryof1-Dsystems.Anexampleisgiventoillustratethevalidityofthisalgorithm.

  • 标签: 海洋工程 二维系统 海洋地震 随机系统 运算法则
  • 简介:Thispaperpresentsthedetaildesignconditions,designcriteriaandmethodsaswellasdesignconclusionsoftheprocess,structureandcorrosionoftheproductionflowlinesandhighpressurewaterinjectionlinesinBZ34-2/4oilfieldinBohaiBay.AtpresentthisdesignrepresentsthedesigncapabilityandlevelinthefieldofthesubmarinepipelineengineeringofChina.

  • 标签: SUBMARINE PIPELINE SLUGGING INHIBITOR RISER inplace
  • 简介:Inthisstudy,thecombinedactionsofwavesandtidalcurrentsinestuarineandcoastalareasareconsideredanda2Dmathematicalmodelforsedimenttransportbywavesandtidalcurrentshasbeenestablishedinorthogonalcurvilinearcoordinates.Non-equilibriumtransportequationsofsuspendedloadandbedloadareusedinthemodel.Theconceptofbackgroundconcentrationisintroduced,andtheformulaofsedimenttransportcapacityoftidalcurrentsfortheOujiangRiverestuaryisobtained.TheDouGuorenformulaisemployedforthesedimenttransportcapacityofwaves.SedimenttransportcapacityintheformofmudandtheintensityofbacksiltingarecalculatedbyuseofLuoZaosen'sformula.Thecalculatedtidalstagesareingoodagreementwiththefielddata,andthecalculatedvelocitiesandflowdirectionsof46verticallinesfor8crosssectionsarealsoingoodagreementwiththemeasureddata.Onsuchabasis,simulationsofbacksiltingafterexcavationofthewaterwaywithasandbarundercomplicatedboundaryconditionsinthenavigationchannelinducedbysuspendedload,bedloadandmudbywavesandtidalcurrentsarediscussed.

  • 标签: 土沙流送 排水沟 泥浆 底沙 悬荷 数学模型