简介:TheanalysisoftherelationshipbetweenseaiceinArcticandAntarctic,andtheSouthernOscillationIndex(SOI)variationonthetemporalscaleofmonth,seasonandyearismadeinthispaper.ThenegativecorrelationbetweenseaiceinArcticandtheSOI.andthepositivecorrelationbetweenseaiceinAntarcticandtheSOIarefound.ThevariationofseaiceinAntarcticPacificseemstoplayanimportantroleintheinfluencetoatmosphere.Theirnonlinearrelationshipspresentmorestronglythanthelinearrelationshipbetweenthem.TherelationshipbetweenseaiceinArcticandAntarcticandtheSOIintheearlystageisinvestigated.Theirvariationshowsperiodicphenomena.ThemaximumcorrelationisusedtobuildthemodelforforecastingthevariationoftheSOIontheconditionoftheseaiceinArcticandAntarctic.Theexplainedvarianceofthesimulatedseriesisgreaterthan0.90.Thereexistsa17-monthperiodintherelationshipbetweenseaiceinArcticandAntarcticandSOI.Theexistingofthecommonfactorwithlargerscaleisdiscussedinthispaper.
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.
简介:Theatmosphericintraseasonaloscillation(ISO)anditsinterannualvariabilityaresimulatedbytheatmosphericgeneralcirculationmodel,whichwasdevelopedattheInstituteofAtmosphericPhysics.Twonumericalexperimentswereperformed,correspondingtotheAMIP-IandAMIP-IIsimulations,respectively.Themodelreasonablyreproducesthemajoraspectsoftheintraseasonaloscillation,includingthepropagatingpropertyandtheseasonaldifferencesinthetropics,thewavenumberstructureofISOintheglobe,andtheglobalcoincidenceintheinterannualvariationofISO.Comparisonoftheresultsbetweenthetwoexperimentssuggeststhatimprovementoftheboundaryforcingorconsideringtheair-seainteractionmayhelptoimprovethesimulationontheISOanditsinterannualvariability.
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.
简介:Abstract.Inthispaper,theforcedoddorderneutraldifferentialequationsoftheformarecon-sidered
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.
简介:Inthispaperweinvestigatetheoscillatorypropertyofthesolutionsofaclassorparaboncpartialfunctionaldifferentialequationswithcontinuousdistrbuteddeviatingarguments.
简介:Inthispaper,thephenomenononcollapsibletubedisplacementoscillation,anewbehaviorofthecollapsibletubepuisatileflowhasbeenstudied.Theexperimentsshowthatthecollapsibletube,inwhichtheflowisperiodicpuisatileintheupstream,willoscillateasasimplesupportedbeamwhenitiscollapsedtocertainextent,andthatifthetubeiscollapsedcontinue,thisoscillationwilltendtoweakandcompletelydisappearlastly.Ananalyticalmodelcorrespondingtothecollapsibletubedisplacementoscillationanditsgovernedequationsaresetupfromtheexperimentbackground.Byanalysingthemodelandsolvingtheequations,thecollapsibletubedisplacementoscillationpatternandtheoscillationoccurringordisappearingcriterionareobtained.Theresultspredictedbythisstudyareinagreementwiththoseobservedfromexperimentphenomena.
简介:Aroboticfishdrivenbyoscillatingfins,"CownoseRay-I",isdeveloped,whichisindorsoventrallyflattenedshapewithoutatail.Theroboticfishiscomposedofabodyandtwolateralfins.Athree-factorkinematicmodelisestablishedandusedinthedesignofamechanism.Bycontrollingthethreekinematicparameters,theroboticfishcanaccelerateandmaneuver.Forwardvelocityisdependentonthelargestamplitudeandthenumberofwavesinthefins,whiletherelativecontributionoffinbeatfrequencytotheforwardvelocityoftheroboticfishisdifferentfromtheusualresult.Ontheotherhand,experimentalresultsonmaneuveringshowthatphasedifferencehasastrongereffectonswervingthanthelargestamplitudetosomeextent.Inaddition,aspropulsionwavespassfromthetrailingedgetotheleadingedge,theroboticfishattainsabackwardvelocityof0.15m·s-1.
简介:1.IntroductionConsiderthefirstorderdifferentialequationwithdeviatingargUmelltTheoscillationofEq.(1)wasstudiedextensivelyinthelastthreedecades.See,forexamDleif--101andthereferencescitedtherein.In1972Ladas.LakshlnhanthamanddeceivedApril1,1997.Re~AugUBt...
简介:PhasecompositeanalysesareconductedtoinvestigatethepossibleeffectoftheMadden–Julianoscillation(MJO)onthespringrainfallanomaliesinEastChinabyusingtheReal-timeMultivariateMJO(RMM)indexfromAustralianMeteorologicalBureau.Theresultsshowthattherainfallanomaliesoverthemid-andlower-valleyofYangtzeRiverarepositivewhentheMJOshiftseastwardtothemid-andeastern-IndianOcean,andanomalousprecipitationoverSouthChinaarepositivewhentheMJOmovesfurthereastwardtothemaritimecontinent,whereasspringrainfallanomaliesoverEastChinaarenegativeintheotherMJOepisodes.TheMJOimpactsontheprecipitationoverEastChinaresultfromthechangesinlarge-scaleatmosphericcirculationaswellasvorticityandwatervaportransportationinthemid-andlower-troposphere.