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94 个结果
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  • 简介:TheanalysisoftherelationshipbetweenseaiceinArcticandAntarctic,andtheSouthernOscillationIndex(SOI)variationonthetemporalscaleofmonth,seasonandyearismadeinthispaper.ThenegativecorrelationbetweenseaiceinArcticandtheSOI.andthepositivecorrelationbetweenseaiceinAntarcticandtheSOIarefound.ThevariationofseaiceinAntarcticPacificseemstoplayanimportantroleintheinfluencetoatmosphere.Theirnonlinearrelationshipspresentmorestronglythanthelinearrelationshipbetweenthem.TherelationshipbetweenseaiceinArcticandAntarcticandtheSOIintheearlystageisinvestigated.Theirvariationshowsperiodicphenomena.ThemaximumcorrelationisusedtobuildthemodelforforecastingthevariationoftheSOIontheconditionoftheseaiceinArcticandAntarctic.Theexplainedvarianceofthesimulatedseriesisgreaterthan0.90.Thereexistsa17-monthperiodintherelationshipbetweenseaiceinArcticandAntarcticandSOI.Theexistingofthecommonfactorwithlargerscaleisdiscussedinthispaper.

  • 标签: analysis of time SCALE nonlinear RELATIONSHIP
  • 简介:TheV^t-integralasdefinedin[2],whichiseqnivalenttoM^2-integrslasdefinedinTrigonometreseriesbyZygmundisusedtosumtrigonometricseiesin[1].Inthispaper,someconvergenttheoremsofV^2-integralareestablished.

  • 标签: V^t-积分 单调性 收敛定理 振动函数 三角序列
  • 简介:Thedelaydifferentialequationwithpiecewiseconstantargumentx′(t)+a(t)x(t)+b(t)x([t-k])=0isconsidered,wherea(t)andb(t)arecontinuousfunctionson[—k,∞),b(t)≥0,kisapositiveintegerand[·]denotesthegreatestintegerfunction.Somenewoscillationandnonoscillationconditionsareobtained.

  • 标签: 延迟微分方程 分段常数 振动方程 连续函数
  • 简介:Temporalandspatialevolutioncharacteristicsofthe30-60dayoscillation(intraseasonaloscillation,ISO)ofsummerrainfallinChinaandtheeffectsofEastAsianmonsoonontherainfallISOareanalyzedinthispaper.Resultsshowthattheannualanddecadalvariationsoftheoscillationexistbetween1960and2008,andtheintensityisweakestinthelate1970sandearly1980s.InthetypicalstrongyearsoftherainfallISOobtainedfromempiricalorthogonalfunctions(EOFmode1),ananticycloneisinnorthwesternPacificandacycloneisintheeastofChina.Inthetypicalweakyears,thewindISOismuchweaker.Thelow-frequencyzonalwindandwatervaportransportfromthelowlatitudestomid-latitudesinthetypicalstrongyears,andtheoscillationstrengthofdiabaticheatingismuchstrongerthanthatintheweakyearsoftherainfallISO.TheanomalycharacteristicsoftherainfallISOshowanti-phasesbetweentheYangtzeRiverbasinandsouthofChina.AsforthetypicalstrongyearsoftherainfallISOintheYangtzeRiverbasin(EOFmode2),themainoscillationcenterofwatervaporisintheeastofChina(20-30°N,110-130°E).Inthepeak(break)phaseoftherainfalloscillation,alow-frequencycyclone(anticyclone)isintheYangtzeRiverbasinandananticyclone(cyclone)isnearTaiwanIsland.Inaddition,thepeakrainfallcorrespondstotheheatsourceintheYangtzeRiverbasinandtheheatsinkintheQinghai-TibetPlateau.AsforthetypicalstrongyearsoftherainfallISOinthesouthofChina,themainoscillationcenterofwatervaporissouthof20°N.Inthepeak(break)phaseoftherainfallISO,alow-frequencycyclone(anticyclone)isinthesouthofChinaandananticyclone(cyclone)isinthePhilippines.ThepeakrainfallcorrespondstotheheatsourceinthesouthofChinaandtheSouthChinaSea,andtheheatsinkinthewestofIndochina.

  • 标签: 热带气象 气象学 天气学 气团
  • 简介:Theatmosphericintraseasonaloscillation(ISO)anditsinterannualvariabilityaresimulatedbytheatmosphericgeneralcirculationmodel,whichwasdevelopedattheInstituteofAtmosphericPhysics.Twonumericalexperimentswereperformed,correspondingtotheAMIP-IandAMIP-IIsimulations,respectively.Themodelreasonablyreproducesthemajoraspectsoftheintraseasonaloscillation,includingthepropagatingpropertyandtheseasonaldifferencesinthetropics,thewavenumberstructureofISOintheglobe,andtheglobalcoincidenceintheinterannualvariationofISO.Comparisonoftheresultsbetweenthetwoexperimentssuggeststhatimprovementoftheboundaryforcingorconsideringtheair-seainteractionmayhelptoimprovethesimulationontheISOanditsinterannualvariability.

  • 标签: simulation INTRASEASONAL OSCILLATION (ISO) COINCIDENCE
  • 简介:Basedonmonthlyrainfalldatafrom80stationsofChinafortheperiodofJanuary1951—February1985analysedintermsofthemaximumentropyspectrumandEEOF(extendedempiricalorthogonalfunction)techniques,thespatialandtemporalfeaturesofquasi-biennialoscillation(QBO)intherainfallareinvestigatedinadetailedmanner,withsomeresultsofinterestacquired.HighlyevidentistheQBOinrainfalloverChina,especiallythemidandlowerreachesoftheChangjiangRiver,theNEsideoftheQinghai-XizangPlateau,NorthChina,thesouthernpartofNEChina,areassouthoftheChangjiangRiverandoftheNanlingmountainregion,andmostofXinjiang.ThespatialwavedescribedbythefirstandsecondeigenvectorsofEEOFforeasternChinaisatypeofwavetravellingfromNEtoSW,indicatingthecycleofpatterns(inthesouthtonorthdirection):dryness(D)-wetness(W)-dryness(D)→southernW-northernslightD→W-D-W→southernD-northernslightW→D-W-Dagain,withthefloodedregionbetweentheChangjiangandHuangheRiversfortheD-W-DoccurrenceandwiththeChangjiangRiverasthedivisionforthesouthernW-northernslightDhappening.Thethirdandfourtheigenvectorsshowastandingwave-likefeatureforthesameeasternpart,indicatingthecycleofD-W-D→transition→W-D-W→transition→D-W-D,again,wherethetransitionmeansthegeneralweakeningofdroughtandfloodingandtheirsubsequentreversaldevelopment.Theamplitudesofthetimecoefficientsofthefirsttwoeigenvectorsareoppositeinthetrendoftheirchangestothoseofthenexttwoandshowaperiodof10—14years.

  • 标签: QBO PRECIPITATION EEOF
  • 简介:InthisstudytherelationshipbetweentheArcticOscillation(AO)andclimateinChinainborealwinterareinvestigated.Correlationanalysisforthelast41yearsshowsthatthewintertemperatureandprecipitationinChinachangeinphasewithAO.Highpostiviecorrelation(>0.04)betweentemperatureandAOappearsinthenorthernChina.HighcorrelationcoefficientsbetweenprecipitationandAOcoverthesouthernChina(closetotheSouthChyinaSea)andthecentralChina(between30°-40°Nandeastof-100°E),withthevaluesvaryingbetween+0.3and+0.4.ItisfoundthatduringthepastseveraldecadestheprecipitationwasstronglyaffectedbyAO,butforthetemperaturetheSiberianHighplaysamoreimportantrole.AttheinterdecadaltimescaletheAOhassignificantinfluenceonbothtemperatureandpreciptiation.MultivariateregressionanalysisdemonstratesthatAOandtheSiberianHighrelatedvarianceintemperatureandprecipitationis35%and11%respectively,Forprecipitation,howevertheportionisratherlow,implyingthatsomeotherfactorsmayberesponsibleforthechangesinprecipitation,inadditiontoAOandtheSiberianHigh.

  • 标签: 冬季 气候 中国 北极振荡 相互关系 温度
  • 简介:Inthispaper,thephenomenononcollapsibletubedisplacementoscillation,anewbehaviorofthecollapsibletubepuisatileflowhasbeenstudied.Theexperimentsshowthatthecollapsibletube,inwhichtheflowisperiodicpuisatileintheupstream,willoscillateasasimplesupportedbeamwhenitiscollapsedtocertainextent,andthatifthetubeiscollapsedcontinue,thisoscillationwilltendtoweakandcompletelydisappearlastly.Ananalyticalmodelcorrespondingtothecollapsibletubedisplacementoscillationanditsgovernedequationsaresetupfromtheexperimentbackground.Byanalysingthemodelandsolvingtheequations,thecollapsibletubedisplacementoscillationpatternandtheoscillationoccurringordisappearingcriterionareobtained.Theresultspredictedbythisstudyareinagreementwiththoseobservedfromexperimentphenomena.

  • 标签: OSCILLATION UPSTREAM UNSTEADY governed disappear criterion
  • 简介:Aroboticfishdrivenbyoscillatingfins,"CownoseRay-I",isdeveloped,whichisindorsoventrallyflattenedshapewithoutatail.Theroboticfishiscomposedofabodyandtwolateralfins.Athree-factorkinematicmodelisestablishedandusedinthedesignofamechanism.Bycontrollingthethreekinematicparameters,theroboticfishcanaccelerateandmaneuver.Forwardvelocityisdependentonthelargestamplitudeandthenumberofwavesinthefins,whiletherelativecontributionoffinbeatfrequencytotheforwardvelocityoftheroboticfishisdifferentfromtheusualresult.Ontheotherhand,experimentalresultsonmaneuveringshowthatphasedifferencehasastrongereffectonswervingthanthelargestamplitudetosomeextent.Inaddition,aspropulsionwavespassfromthetrailingedgetotheleadingedge,theroboticfishattainsabackwardvelocityof0.15m·s-1.

  • 标签: ROBOTIC fish pectoral OSCILLATION PROPULSION LARGEST
  • 简介:为有抑制Δ~2x_n+p_nΔx_n+F的非线性的延期差别方程的一些新摆动标准(n,x_(n-τ),Δx_(n-σ))=0,n=0,1,2,...,(*)被给。我们的结果部分解决摆姿势在的开的问题[数学。Bohemica,125(2000),421-430]。另外,我们将为(*)的特殊情况建立一些新摆动标准,它在文学改进一些知道thewell的结果。

  • 标签: 二阶微分方程 振荡 非线性 时滞 阻尼
  • 简介:1.IntroductionConsiderthefirstorderdifferentialequationwithdeviatingargUmelltTheoscillationofEq.(1)wasstudiedextensivelyinthelastthreedecades.See,forexamDleif--101andthereferencescitedtherein.In1972Ladas.LakshlnhanthamanddeceivedApril1,1997.Re~AugUBt...

  • 标签: OSCILLATION DIFFERENTIAL EQUATION deviating ARGUMENT
  • 简介:PhasecompositeanalysesareconductedtoinvestigatethepossibleeffectoftheMadden–Julianoscillation(MJO)onthespringrainfallanomaliesinEastChinabyusingtheReal-timeMultivariateMJO(RMM)indexfromAustralianMeteorologicalBureau.Theresultsshowthattherainfallanomaliesoverthemid-andlower-valleyofYangtzeRiverarepositivewhentheMJOshiftseastwardtothemid-andeastern-IndianOcean,andanomalousprecipitationoverSouthChinaarepositivewhentheMJOmovesfurthereastwardtothemaritimecontinent,whereasspringrainfallanomaliesoverEastChinaarenegativeintheotherMJOepisodes.TheMJOimpactsontheprecipitationoverEastChinaresultfromthechangesinlarge-scaleatmosphericcirculationaswellasvorticityandwatervaportransportationinthemid-andlower-troposphere.

  • 标签: MJO activities spring precipitation over East