简介:Thetyphoon,asamaturetropicalcyclonethatdevelopsinthewesternpartoftheNorthPacificOceanwithhighwindspeedandheavyrainfall,isoneofthemostlethalandcostlyofnaturaldisastersforthedenselypopulatedcountriesofEastAsia.Itcanbeeasilydetectedbyspace-bornesensorsoperatedatmicrowave,visibleorinfraredbands(Liuetal.,2014).SyntheticApertureRadar(SAR)is
简介:Aregionalsurfacecarbondioxide(CO_2)fluxinversionsystem,theTan-Tracker-Region,wasdevelopedbyincorporatinganassimilationschemeintotheCommunityMultiscaleAirQuality(CMAQ)regionalchemicaltransportmodeltoresolvefine-scaleCO_2variabilityoverEastAsia.Theproperorthogonaldecomposition-basedensemblefour-dimensionalvariationaldataassimilationapproach(POD-4DVar)isthecorealgorithmforthejointassimilationframework,andsimultaneousassimilationsofCO_2concentrationsandsurfaceCO_2fluxesareappliedtohelpreducetheuncertaintyininitialCO_2concentrations.ApersistencedynamicalmodelwasdevelopedtodescribetheevolutionofthesurfaceCO_2fluxesandhelpavoidthe'signal-to-noise'problem;thus,CO_2fluxescouldbeestimatedasawholeatthemodelgridscale,withbetteruseofobservationinformation.Theperformanceoftheregionalinversionsystemwasevaluatedthroughagroupofsingle-observation-basedobservingsystemsimulationexperiments(OSSEs).TheresultsoftheexperimentssuggestthatareliableperformanceofTan-Tracker-Regionisdependentoncertainassimilationparameterchoices,forexample,anoptimizedwindowlengthofapproximately3h,anensemblesizeofapproximately100,andacovariancelocalizationradiusofapproximately320km.Thisisprobablyduetothestrongdiurnalvariationandspatialheterogeneityinthefine-scaleCMAQsimulation,whichcouldaffecttheperformanceoftheregionalinversionsystem.Inaddition,becauseallobservationscanbeartificiallyobtainedinOSSEs,theperformanceofTan-Tracker-RegionwasfurtherevaluatedthroughdifferentdensitiesoftheartificialobservationnetworkindifferentCO_2fluxsituations.TheresultsindicatethatmoreobservationsiteswouldbeusefultosystematicallyimprovetheestimationofCO_2concentrationandfluxinlargeareasoverthemodeldomain.TheworkpresentedhereformsafoundationforfutureresearchinwhichathoroughestimationofCO_2fluxvariability
简介:于2016年6-11月,在辽河口盘锦市湿地科学研究所基地的芦苇(Phragmitesaustralis)盐沼、笔架岭的盐地碱蓬(Suaedasalsa)盐沼和光滩中,采用静态箱-气相色谱法,采集气体样品,在实验室中,测量和计算出气样的CO2浓度,估算CO2排放通量;分析CO2排放通量与土壤温度、氧化还原电位、pH和电导率等环境因子的关系。结果表明,辽河口芦苇盐沼、盐地碱蓬盐沼(涨潮前)和光滩(涨潮前)CO2排放通量平均值分别为(1187.7±649.0)mg/(m^2·h)、(362.4±146.1)mg/(m^2·h)和(91.1±21.1)mg/(m^2·h)。3种类型湿地CO2排放通量差异显著(n=24,p〈0.01),芦苇盐沼CO2排放通量最高,光滩的CO2排放通量最低。在涨潮中,盐地碱蓬盐沼和光滩的CO2排放通量平均值分别为(127.9±90.9)mg/(m^2·h)和(45.8±21.1)mg/(m^2·h),显著低于涨潮前的CO2排放通量(n=24,p〈0.01)。各类型湿地CO2排放通量与土壤电导率显著负相关(n=24,p〈0.01),说明土壤盐分是影响不同类型湿地CO2排放通量的关键环境因子。
简介:孔隙结构特征及类型划分对低渗透储层勘探开发至关重要,基于多重分形理论与核磁共振实验,对东营凹陷南坡沙河街组沙四段(ES4)复杂低渗透砂岩进行孔隙结构研究。首先,根据岩心物性、铸体薄片、压汞等资料所反映的孔隙结构参数差异,将研究区的岩石孔隙结构类型划分了3大类5小类;然后,针对不同类型岩石的核磁共振T2谱进行插值并计算其对数坐标下的一维、三维分形维数以及多重分形谱,并提取多重分形参数奇异性强度α、分布稠密度f(a),结果显示孔隙结构类型不同,盒维数尤其是多重分形参数值差异明显,孔隙结构好,其a、f(a)偏向高值,以此划分孔隙结构类型与压汞、薄片分析结果基本一致;最后,将该方法应用到核磁共振测井剖面上,应用效果较好,表明多重分形是核磁共振T2谱的一种属性,利用核磁测井T2谱多重分形特征及参数能够连续较好地评价低渗透砂岩孔隙结构类型与预测有效储层。
简介:AsshaleexploitationisstillinitsinfancyoutsideNorthAmericamuchresearcheffortisbeingchannelledintovariousaspectsofgeochemicalcharacterizationofshalestoidentifythemostprospectivebasins,formationsandmaptheirpetroleumgenerationcapabilitiesacrosslocal,regionalandbasin-widescales.Themeasurementoftotalorganiccarbon,distinguishingandcategorizingthekerogentypesintermsoil-proneversusgas-prone,andusingvitrinitereflectanceandRock-Evaldatatoestimatethermalmaturityarestandardpracticeintheindustryandappliedtosamplesfrommostwellboresdrilled.Itisthetrendsofstableisotopesratios,particularlythoseofcarbon,thewetnessratio(C1/∑(C2+C3)),andcertainchemicalbiomarkersthathaveprovedtobemostinformativeaboutthestatusofshalesasapetroleumsystem.Thesedatamakeitpossibletoidentifyproduction'sweet-spots',discriminateoil-,gas-liquid-andgas-proneshalesfromkerogencompositionsandthermalmaturities.Rolloversandreversalsofethaneandpropanecarbonisotoperatiosareparticularlyindicativeofhighthermalmaturityexposureofanorganic-richshale.Comparisonsofhopane,streraneandterpanebiomarkerswithvitrinitereflectance(Ro)measurementsofthermalmaturityhighlightdiscrepanciessuggestingthatRoisnotalwaysareliableindicatorofthermalmaturity.Majorandtraceelementinorganicgeochemistrydataandratiosprovidesusefulinformationregardingprovenance,paleoenvironments,andstratigraphic-layerdiscrimination.Thisreviewconsidersthedatameasurement,analysisandinterpretationoftechniquesassociatedwithkerogentyping,thermalmaturity,stableandnon-stableisotopicratiosforrocksandgasesderivedfromthem,productionsweet-spotidentification,geochemicalbiomarkersandinorganicchemicalindicators.Italsohighlightsuncertaintiesanddiscrepanciesobservedintheirpracticalapplication,andthenumerousoutstandingquestionsassociatedwiththem.
简介:以滇西北碧塔海泥炭沼泽土壤为研究对象,通过野外测量和室内分析相结合的方法,研究牦牛(Bosmutus)践踏和牦牛粪影响下的土壤总有机碳含量、全氮含量和N_2O排放通量。结果表明,牦牛践踏显著抑制了土壤N_2O的排放;牦牛粪的输入促进了土壤N_2O的排放,且牦牛粪分解前期是N_2O排放的高峰期。在0~30cm深度土层内,牦牛放牧使土壤总有机碳含量增加,牦牛践踏和牦牛粪都促进了土壤总有机碳含量的增加,增加比例分别为39.27%和12.19%;随着土壤深度的增加,粪斑样方土壤总有机碳含量显著减小,践踏样方土壤总有机碳含量略有增加。牦牛放牧使土壤全氮含量增加,牦牛践踏和牦牛粪都促进了土壤全氮含量的增加,增加比例分别为50.56%和12.76%;随着土壤深度的增加,践踏样方和粪斑样方土壤全氮含量都在减小。
简介:Newsatellite-derivedlatentandsensibleheatfluxesareperformedbyusingWindSatwindspeed,WindSatseasurfacetemperature,theEuropeanCentreforMedium-rangeWeatherForecasting(ECMWF)airhumidity,andECMWFairtemperaturefrom2004to2014.The55mooredbuoysareusedtovalidatethembyusingthe30minand25kmcollocationwindow.Furthermore,theobjectivelyanalyzedair-seaheatfluxes(OAFlux)productsandtheNationalCentersforEnvironmentalPrediction-NationalCenterforAtmosphericResearchreanalysis2(NCEP2)productsarealsousedforglobalcomparisons.ThemeanbiasesofsensibleandlatentheatfluxesbetweenWindSatfluxresultsandbuoyfluxdataare–0.39and–8.09W/m~2,respectively.Inaddition,therootmean-square(RMS)errorsofthesensibleandlatentheatfluxesbetweenthemare5.53and24.69W/m~2,respectively.TheRMSerrorsofsensibleandlatentheatfluxesareobservedtograduallyincreasewithanincreasingbuoywindspeed.Thedifferenceshowsdifferentcharacteristicswithanincreasingseasurfacetemperature,airhumidity,andairtemperature.ThezonalaveragelatentfluxeshavesomehighregionswhicharemainlylocatedinthetradewindzoneswherestrongwindscarrydryairinJanuary,andthemaximumvaluecentersarefoundintheeasternwatersofJapanandontheUSeastcoast.Overall,theseasonalvariabilityispronouncedintheIndianOcean,thePacificOcean,andtheAtlanticOcean.Thethreesensibleandlatentheatfluxeshavesimilarlatitudinaldependencies;however,somedifferencesarefoundinsomelocalregions.
简介:镁同位素示踪深部碳循环研究在过去一年取得了很大进展。这些进展包括蚀变洋壳、沉积物、深海橄榄岩和再循环榴辉岩的Mg同位素组成,具有EM—I和HIMU同位素特征的低δ^26Mg玄武岩成因,低δ^26Mg玄武岩熔融p-t条件的Mg-Sr同位素制约,Mg同位素揭示的大陆岩石圈地幔的碳酸盐交代作用,特提斯洋俯冲板块导致的深部碳循环,和富Na碳酸盐岩浆的Mg同位素分异。然而仍有许多重要科学问题尚不清楚,包括:(1)如何区分再循环沉积碳酸盐岩和再循环碳酸盐化榴辉岩对地幔Mg同位素的影响?(2)板块俯冲过程中Mg同位素地球化学行为和为什么岛弧玄武岩没有低δ^26Mg特征?(3)再循环碳在地幔的储存部位及存留时间?(4)普通碳酸盐岩浆的Mg同位素如何分异?(5)如何示踪那些不含Mg或含Mg很少的再循环碳酸盐,如方解石、文石、菱铁矿?这些问题指明了未来的重要研究领域。