学科分类
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7 个结果
  • 简介:Adiscrepancyremainsinthefirsttwoleadingempiricalorthogonalfunction(EOF)modesofthetropicalPacificseasurfacetemperatureanomaly(SSTA)basedonobservationssincethe1980s.TheEOF1mode,representingtheElNino-SouthernOscillation(ENSO),isarobustresult.However,theEOF2featureseitherElNinoModoki(EM)orENSOevolutionduringdifferentperiods,whichisprobablyassociatedwiththeimpactsofglobalwarming.TheunderlyingquestioniswhattheEOF2modeofthetropicalPacificwouldbewithoutglobalwarming.UsingtheCMIP5preindustrialscenariotoexcludetheinfluenceofglobalwarming,wefindthattheEOF1modeofthetropicalPacificSSTArepresentsENSOandthattheEOF2modeisnotEM.Accordingtothelead–lagcorrelationbetweentheENSOandEOF2modes,thelinkagebetweenthesetwomodesisasfollows:…ElNino→EOF2→LaNina→–EOF2→ElNino….Byanalyzingtheevolutionofseasurfacetemperature,surfacewind,andsubsurfaceoceantemperatureanomalies,wefindthemechanismlinkingtheENSOandEOF2modesistheair–seainteractionassociatedwiththeENSOcycle.ThisresultsuggeststhattheEOF2moderepresentsanaspectofENSOevolutionunderpreindustrialconditions.Therefore,thisstudyfurtherindicatesthattheEMisprobablyduetotheinfluenceofglobalwarming.

  • 标签: El Nino-Southern Oscillation(ENSO) ENSO evolution global
  • 简介:PlatesubductiondrivesboththeinternalconvectionandthesurfacegeologyofthesolidEarth.Despitetherapidincreaseofcomputationalpower,itremainschallengingforgeodynamicmodelstoreproducethehistoryofEarth-likesubductionandassociatedmantleflow.Here,basedonanadaptiveapproachofsequentialdataassimilation,wepresentahigh-resolutionglobalmodelsincethemid-Mesozoic.ThismodelincorporatesthethermalstructureandsurfacekinematicsoftectonicplatesbasedonarecentplatereconstructiontoreproducetheobservedsubductionconfigurationandEarth-likeconvection.Introductionoftemperature-andcomposition-dependentrheologyallowsforincorporationofmanynaturalcomplexities,suchasinitiationofsubductionzones,reversalofsubductionpolarity,anddetailedplate-boundarydynamics.Theresultantpresent-dayslabgeometrywellmatchesBenioffzonesandseismictomographyatdepths<1500km,makingitpossibletohindcastpastsubductiondynamicsandmantleflow.Forexample,themodelproducesaflatFarallonslabbeneathNorthAmericaduringtheLateCretaceoustoEarlyCenozoic,afeaturethathasbeengeodynamicallychallengingtoreproduce.Thishigh-resolutionmodelcanalsocapturedetailsofthe4-Devolutionofslabsandtheambientmantle,suchastemporallyandspatiallyvaryingmantleflowassociatedwithevolvingslabgeometryandbuoyancyflux,aswellastheformationofshallowslabtearsduetosubductionofyoungseafloorsandtheresultingcomplexmantledeformation.Suchageodynamicframeworkservestofurtherconstrainuncertainplatereconstructioninthegeologicalpast,andtobetterunderstandtheoriginofenigmaticmantleseismicfeatures.

  • 标签: GLOBAL SUBDUCTION model data ASSIMILATION Earth-like
  • 简介:WepresentpreliminaryresultsofanewglobalMagnetohydrodynamics(MHD)simulationmodeloftheJovianmagnetosphere.ThemodelincorporatesmassloadingfromJupiter'ssatelliteIo,theplanet'sfastcorotation,andelectrostaticcouplingbetweenitsmagnetosphereandionosphere(M-Icoupling).ThebasicconfigurationoftheJovianmagnetosphereincludingtheequatorialplasmaflowpattern,thecorotationenforcementcurrentsystem,andthefieldalignedcurrents(FACs)intheionospherearepresentedunderanantiparallelinterplanetarymagneticfield(IMF)condition.Thesimulationmodelresultsforequatorialdensityandpressureprofilesareconsistentwithresultsfromdata-basedempiricalmodels.ItisalsofoundthattherearesimilaritiesbetweentheFACsdistributionintheionosphereandtheobservedaurorafeatures,showingthepotentialapplicationofthesimpleionosphericmodeltothecomplicatedM-Icoupling.ThismodelwillhelpdeepenourunderstandingoftheglobaldynamicsoftheJovianmagnetosphere.

  • 标签: JUPITER MAGNETOSPHERE magnetohydrodynamic(MHD)simulation
  • 简介:Climatesystemmodelsareusefultoolsforunderstandingtheinteractionsamongthecomponentsoftheclimatesystemandpredicting/projectingfutureclimatechange.ThedevelopmentofclimatemodelshasbeenacentralfocusoftheStateKeyLaboratoryofNumericalModelingforAtmosphericSciencesandGeophysicalFluidDynamics,InstituteofAtmosphericPhysics,ChineseAcademyofSciences(LASG/IAP)sincetheestablishmentofthelaboratoryin1985.InChina,manypioneeringcomponentmodelsandfullycoupledmodelsoftheclimatesystemhavebeendevelopedbyLASG/IAP.ThefullycoupledclimatesystemdevelopedintherecentdecadeisnamedFGOALS(FlexibleGlobalOcean-Atmosphere-LandSystemModel).Inthispaper,anapplication-orientedreviewoftheLASG/IAPFGOALSmodelispresented.Theimprovedmodelperformancesaredemonstratedinthecontextofcloud-radiationprocesses,Asianmonsoon,ENSOphenomena,AtlanticMeridionalOverturningCirculation(AMOC)andseaice.TheFGOALSmodelhascontributedtobothCMIP5(CoupledModelIntercomparisonProject-phase5)andIPCC(IntergovernmentalPanelonClimateChange)AR5(theFifthAssessmentReport).ThereleaseofFGOALSdatahassupportedthepublicationofnearly500papersaroundtheworld.TheresultsofFGOALSarecited~106timesintheIPCCWG1(WorkingGroup1)AR5.Inadditiontothetraditionallong-termsimulationsandprojections,near-termdecadalclimatepredictionisanewsetofCMIPexperiment,progressofLAGS/IAPinthedevelopmentofneartermdecadalpredictionsystemisreviewed.TheFGOALSmodelhassupportedmanyChinesenational-levelresearchprojectsandcontributedtothenationalclimatechangeassessmentreport.ThecrucialroleofFGOALSasamodelingtoolforsupportingclimatesciencesishighlightedbydemonstratingthemodel’sperformancesinthesimulationoftheevolutionofEarth’sclimatefromthepasttothefuture.

  • 标签: CLIMATE system model FGOALS CLIMATE VARIABILITY
  • 简介:Thetriangulationofredspriteswasobtained,basedonconcurrentobservationsoveramesoscaleconvectivesystem(MCS)inNorthChinafromtwostationsseparatedbyabout450km.Inaddition,broadbandsfericsfromthesprite-producinglightningweremeasuredatfivegroundstations,makingitpossibletolocateandidentifytheindividualcausativelightningdischargesfordifferentelementsinthisdancingspriteevent.TheresultsofouranalysesindicatethatthespriteswereproducedabovethetrailingstratiformregionoftheMCS,andtheirparentstrokeswerelocatedmainlyintheperipheralareaofthestratiform.Thelateraloffsetbetweenspritesandcausativestrokesrangesfromafewkmtomorethan50km.Inaparticularlybrightsprite,withadistincthalofeatureandstreamersdescendingdowntoanaltitudeofapproximately48km,thespritecurrentsignalidentifiedintheelectricsferic,measuredatarangeofabout1,110km,peakedatapproximately1msafterthereturnstroke.

  • 标签: SPRITE TRIANGULATION PEAK current hybrid location
  • 简介:PrecipitationobservationscollectedatweatherstationsineasternChina,theNCEP/NCARreanalysisdata,thetropicalcyclone(TC)BestTrackDataset,andasensitivitynumericalexperimentwereusedinthepresentstudytoinvestigatetheroleintheEastAsiansummermonsoon(EASM)systemplayedbyfrequentTCactivitiesoverthewesternNorthPacific(WNP).Resultsindicatedthat,inactiveTCyears,theEASMisstrongerandthesoutherlywindsinthelowertroposphereadvancefarthernorthandreachhigherlatitudes.Meanwhile,themonsoonrainbeltremainsinthelowerandmiddlereachesoftheYangtzeRivervalleyforarelativelyshortperiod,leadingtolessprecipitationthere.BoththewesternPacificsubtropicalhighandtheSouthAsianhighweakenwiththenorthwardshiftoftheridgelinesforbothhigh-pressuresystemsaswellastheEastAsiansubtropicalupper-leveljet.Therefore,theimpactsoffrequentTCactivitiesovertheWNPoneachindividualcomponentoftheEASMareinphasewiththoseofthestrongerEASMitself,amplifyingfeaturesofthealreadystrengthenedEASM.

  • 标签: East Asian summer MONSOON TROPICAL CYCLONE