简介:ThecropmodelWorldFoodStudies(WOFOST)wastunedandvalidatedwithmeteorologicalaswellaswinterwheatgrowthandyielddataat24stationsin5provincesofNorthChinafrom1997to2003.Theparameterizationobtainedbythetuningwasthenusedtomodeltheimpactsofclimatechangeonwinterwheatgrowthforallstationsusinglong-termweatherdatafrom1950to2000.Twosimulationsweremade,onewithallmeteorologicaldata(rainfed)andtheotherwithoutwaterstress(potential).Theresultsindicatethatthefloweringandmaturitydatesoccurred3.3and3daysearlierinthe1990sthanthatinthe1960sduetoa0.65℃temperatureincrease.Thesimulatedrainfedyieldsshowthattheaveragedroughtinducedyields(potentialminusrainfedyields)havedecreasedby9.7%overthelast50years.Thisistobecomparedwitha0.02%decreaseinyieldiftheprecipitationlimitislifted.Althoughtheprecipitationduringthegrowingseasonhasdecreasedoverthelast50years,thedroughteffectsontherainfedyieldsremainedtobepracticallyunchangedasthespringprecipitationdidnotdecreasemarkedly.
简介:Thisstudyfocusesonthedecadalvariabilityoftropicalcyclones(TC)overtheWesternNorthPacific(WNP)andhowthesechangesarerelatedtotheMadden-JulianOscillation(MJO).ItwasdonewiththehelpoftheReal-timeMultivariateMJOindexfromtheAustralianGovernmentBureauofMeteorologyoftheCentreforAustralianWeatherandClimateResearch,TCdatafromtheJointTyphoonWarmingCenterbesttrackdatasets,anddailyandmonthlydatasetsfromtheNCEP/NCARreanalysiscenter.TheresultsshowthattheTCfrequencyintheWNPexhibitedastatisticallysignificantdecreaseduring1998-2010comparedtoduring1979-1997.ThedecreaseinTCfrequencyintheWNPmainlyoccurredduringMJOactivephases(i.e.,phases4,5,6,and7).FurtherinvestigationoftheclimatebackgroundandthepropagationdifferencesoftheMJObetween1979-1997and1998-2010wasperformed.TheLaNina-liketropicalseasurfacetemperaturecoolingcausedstrongerWalkercirculationandthusinducedunfavorableatmosphereconditionsforWNPTCgenesisincludingalow-leveleasterlyanomaly,anegativerelativevorticityanomaly,anincreaseinsea-levelpressure,andstrongerverticalwindshear.Moreover,shorteningoftheMJOcycle,declineinthedurationoftheactivephasesintheWNP,andeasterlyanomalyandshrinkageoftheconvectionareaduringMJOactivephasesmayalsopartlyexplainthedecadalvariationofTC.
简介:Usingthehigh-qualityobservedmeteorologicaldata,changesofthethermalconditionsandprecipitationovertheNorthChinaPlainfrom1961to2009wereexamined.Trendsofaccumulatedtemperatureandnegativetemperature,growingseasonduration,aswellasseasonalandannualrainfallsat48stationswereanalyzed.Theresultsshowthattheaccumulatedtemperatureincreasedsignificantlyby348.5℃dayduetoglobalwarmingduring1961-2009whiletheabsoluteaccumulatednegativetemperaturedecreasedapparentlyby175.3℃day.Thestartofgrowingseasondisplayedasignificantnegativetrendof-14.3daysduring1961-2009,buttheendofgrowingseasondelayedinsignificantlyby6.7days.Asaresult,thelengthofgrowingseasonincreasedby21.0days.Theannualandautumnrainfallsdecreasedslightlywhilesummerrainfallandsummerrainydaysdecreasedsignificantly.Incontrast,springrainfallincreasedslightlywithoutsignificanttrends.AlltheresultsindicatethatthethermalconditionswereimprovedtobenefitthecropgrowthovertheNorthChinaPlainduring1961-2009,andthedecreasingannualandsummerrainfallshadnodirectnegativeimpactonthecropgrowth.ButthedecreasingsummerrainfallwaslikelytoinfluencethewaterresourcesinNorthChina,especiallytheundergroundwater,reservoirwater,aswellasriverrunoff,whichwouldhaveinfluencedtheirrigationofagriculture.
简介:Thedifferencesintheclimatologyofextratropicaltransition(ET)ofwesternNorthPacifictropicalcyclones(TCs)wereinvestigatedinthisstudyusingtheTCsbest-trackdatasetsofChinaMeteorologicalAdministration(CMA),JapanMeteorologicalAgency(JMA)andtheJointTyphoonWarningCenter(JTWC).TheresultsshowthattheETidentification,ETcompletiontime,andpost-ETdurationreportedintheJTWCdatasetaregreatlydifferentfromthoseinCMAandJMAdatasetsduring2004-2010.However,thekeydifferencesbetweentheCMAandJMAdatasetsfrom1951to2010aretheETidentificationandthepost-ETduration,becauseofinconsistentobjectiveETcriteriausedinthecenters.FurtheranalysisindicatesthatannualETpercentageofCMAwaslowerthanthatofJMA,andexhibitedaninterannualdecreasingtrend,whilethatofJMAwasanunchangedtrend.ThewesternNorthPacificETeventsoccurredmainlyduringtheperiodJunetoNovember.ThelatitudeofEToccurrenceshiftednorthwardfromFebruarytoAugust,followedbyasouthwardshift.MostofETeventswereobservedbetween35°Nand45°N.Fromaregionalperspective,TCstendedtoundergoETinJapanandtheoceaneasttoit.ItisfoundthatTCswhichexperiencedtheETprocessathigherlatitudesweregenerallymoreintenseattheETcompletiontime.TCscompletingtheEToverlandoroffshorewereweakerthanthosefinishingtheETovertheocean.MostoftheTCsweakened24hbeforethecompletionofET.Incontrast,21%(27%)oftheTCsshowedanintensificationprocessbasedontheCMA(JMA)datasetduringthepost-ETperiod.TheresultspresentedinthisstudyindicatethatconsistentETdeterminationcriteriaareneededtoreducetheuncertaintyinvolvedinETidentificationamongthecenters.
简介:用大气的研究(NCEP/NCAR)和在冬季期间聚集的客观地分析的由空至海的热流动(OAFlux)的环境研究/公民中心的国家中心的每月的分析数据,单个向量分解(SVD)分析被进行揭示在在北方太平洋上在500hPa(Z500)加热异例和geopotential高度的自台湾东面的菲律宾海流向日本的暖流水兵之间的联合模式。第一个SVD模式证明当加热异例的北自台湾东面的菲律宾海流向日本的暖流水兵是积极的时,在北方太平洋的中央、西方的节的Z500是反常地低的。由填写气象学的领域异例在积极(或否定)年,这被揭示了当时阿留申群岛之土人低加深(或shallows),在西北弯屈自台湾东面的菲律宾海流向日本的暖流加强的overlying(或变弱)并且导致近表面的空气凉爽(或温暖)。而且,这增加(或减少)向上的热流动异例并且冷却(或温暖)海表面温度(SST)因此。在自台湾东面的菲律宾海流向日本的暖流和它的下游的区域的附近,沿着纬度的空气温度的垂直结构是baroclinic;然而,geopotential高度是相等地barotropic,哪个礼品凉爽的马槽(或温暖的山脉)空间结构。分叉的风和垂直速度被介绍显示出异常带的发行量房间。这些被升起描绘(或下降)在中央诺思太平洋的空气,它向西流动并且向上面的对流层东方,下降(或上升)在自台湾东面的菲律宾海流向日本的暖流并且在北美洲的西方的节,然后加强(或变弱)中间纬度的带的房间(MZC)。
简介:Inthisarticle,anewdefinitionfortheNorthHuaiheRiverrainyseason(NHRS)ispresentedusingsummerdailyprecipitationinEastChinaandsubtropicalhighridgeaxisat500hPa.BycalculatingtheannualprecipitationamountsintheNHRSandMeiyuoftheYangtze-HuaiheRiversbasin(YHMY)from1961to2009,thedatesofprecipitationbeginningandendingaswellasthedurationofthetworainyseasonsinthe49yearsareanalyzed.AtmosphericcirculationcharacteristicsinpositiveandnegativeprecipitationanomalyyearsduringtheNHRSarealsostudied.Resultsareshownasfollows.(1)ThenewdefinitionfortheNHRSismucheasiertouse.Itinvolvesonlytwometeorologicalfactors,makingitsapplicationmorepractical.ItcanalsodistinguishtworainyperiodsoftheNHRSmoreobjectively.(2)TheaveragedurationoftheNHRSissimilartothatoftheYHMY,exceptthatitsaveragedatesofbeginningandendingareaboutoneweeklaterthanthoseoftheYHMY.TheaverageprecipitationoftheNHRSisslightlylessthanthatoftheYHMY,andtheyearlyprecipitationvariationofthetworainyseasonsaresimilartoeachotherwithnoobviousincreasingordecreasingtrendinthe49years,butwithdistinguisheddecadalandinter-annualvariations.(3)Inpositiveprecipitationanomalyyears,theSouthAsianhighmovesmorenorthwardandmoreeastward,thewesternPacificsubtropicalhighislocatedmorenorthwardandwestward,andthesummermonsoonisstrongerthannormal,resultingintheconvergenceofthewarmandmoistsouthwesterlyairflowfromthewestsideofthesubtropicalhighandthecoldairfromthenorthsideofthenortheasttroughinNorthHuaiheRiverbasin.
简介:我们在东亚(EA)上在夏天intraseasonal摆动(ISO)的27年的强迫的模拟评估GAMIL1.1.1的表演西方的诺思太平洋(WNP)。评价基于二项措施:climatologicalISO(CISO)和短暂ISO(TISO)。CISO是对年度周期锁阶段并且描述季节的行军的ISO部件。TISO是逐年变化的ISO部件。模型相当捕获ISO的许多观察特征,包括逐步向北方CISO的雨带进展,在华南海菲律宾的海(SCS-PS)和长江盆(YRB)的TISO的主导的频率,向北方3050天的TISO的繁殖并且向西在SCS-PS上的1225天的TISO模式的繁殖,和在YRB上的三个主要TISO模式的带的宣传特征。然而,模型有著名缺乏。这些包括与CISO联系的华南海季风的早发作,太快向北方到40°N和10°N的CISO信号南方的缺席的从20°N的CISO的繁殖,3050天的TISO模式的缺乏的东方繁殖和在YRBTISO模式的向南方的繁殖的缺席。作者发现在ISO模拟的缺乏是仔细与模型在平均数的偏爱有关说,建议模型的改进意味着状态为intraseasonal变化的现实主义的模拟是关键的。
简介:否定阶段的诺思大西洋摆动(NAO)事件通常比积极阶段的强壮,即,有NAO的阶段力量不对称现象。在这个工作,我们用有条件的非线性的最佳的不安(CNOP)探索NAO的这不对称现象方法与一三水平全球伪因地球自转而引起光谱模型。与冬季climatological流动强迫,CNOP方法识别在给定的起始的限制下面触发最强壮的NAO事件的不安,这被显示出。同时,NAO的阶段力量不对称现象特征能被揭示。由与线性结果作比较,我们发现不安自我相互作用的过程支持否定NAO事件的发作,它比在积极NAO发作期间强壮得多。结果在北方的冬季(DecemberFebruary)用climatological和带平均数的流动独立被获得19792006作为起始的基本状态。我们得出结论,基于NAO发作是一个非线性的起始值的问题的事实,那阶段力量不对称现象是NAO的一个内在的特征。
简介:BasedontheCMAtropicalcyclone(TC)besttrackdataaswellasthereanalysisdatasetsfromtheNCEP/NCARandNOAA,thevariationcharacteristicsofTCnumberfrom1949to2013overthewesternNorthPacific(includingtheSouthChinaSea)areexamined.Notably,thetimeseriesofTCnumberexhibitsasignificantabruptchangefrommoretolessaround1995.ComparativeanalysisindicatesthattheenvironmentalfactorsnecessarytoTCformationalsochangesignificantlyaroundthemid-1990s.After1995,accompanyingwithanomalouswarmseasurfacetemperature(SST)inwesternequatorialPacific,aLaNia-likepatternintropicalPacificappearsobviously.However,comparedwiththeperiodbefore1995,theverticalupwardmovementdecreases,verticalshearoftroposphericzonalwindincreases,andsealevelpressure(SLP)rises,allofwhichareunfavorabletoTCformationandworktogethertomakeTCnumberreducemarkedlyafter1995.Furthermore,whenthetypicalinterannualmoreandlessTCsyearsareselectedinthetwoseparatestagesbeforeandafter1995,therelativeimportanceofoceanicandatmosphericenvironmentsininterannualTCgenerationisalsoinvestigatedrespectively.TheresultsimplythattheSSToverthetropicalPacificexertsrelativelyimportantinfluenceonTCformationbefore1995whereastheatmosphericcirculationplaysamoreprominentroleinthegenerationofTCafter1995.
简介:BasedonanalysesoftherelationshipbetweenPacificMeridionalMode(PMM)andnumberoftropicalcyclones(TCs)activityoverthewesternNorthPacific,theimpactsofthePMMonTcactivityoverthewesternNorthPacificarestudiedusingnumericalsimulationswithanAtmosphericGeneralCirculationModel(CAM3)ofNationalCenterforAtmosphericResearch(ofUSA).TheresultshowsthatthePMMhasimpactsonthelarge-scalegeneratingenvironmentofTCs,thusaffectingtheirnumberandstrength.ThenumericalsimulationsusingtheNCARCAM3indicatethatwiththeinclusionoftheforcingfromseasurfacetemperature(SST)ofthePMM,thereappearsadecreasedmagnitudeoftheverticalzonalwindshear,largeproportionofrelativehumidity,anomalouswesterlywindatlowlevelsandanomalouseasterlywindathighlevels,inassociationwithanomalouscycloniccirculationatlowlevelsandanomalousanti-cycloniccirculationathighlevelsoverthetropicalwesternPacific.Thus,thePMMprovidesfavorableenvironmentforthetyphoongenesis.Inthesensitivityexperiment,TCshavelargerstrength,lowerSSTatthecenter,strongertangentialwindat850hPaandintensifiedwarmcoresathighlevels.Inthispaper,thesimulationresultsaresimilartothatinthedataanalyses,whichrevealstheimportantimpactofthePMMonTCactivityoverthewesternNorthPacific.
简介:Anintercomparisonofsummertime(JJA)subtropicalgeopotentialheightsfromtheERA-40andNCEP/NCARreanalysisisspecificallyconductedoverEastEurasiaandthewesternNorthPacific.TheNCEP/NCARisobviouslylowerthantheERA-40inthemid-to-lowertroposphereinmostregionsofEastEurasiabeforethemid-1970s,butbecomeshigherthantheERA-40afterthemid-1970sandthusdemonstratesstrongerincreasedtrendsduringtheperiodof1958-2001.BothreanalysesarelowerthantheobservationsinmostregionsofChina.TheNCEP/NCARespeciallyshowstremendouslysystematiclowervaluesbeforethemid-1960sanddisplaysabruptchangesbeforethe1970s.SeveralindicesofthewesternNorthPacificsubtropicalhigh(WNPSH),calculatedfrombothreanalyzedsummergeopotentialheights,alsorevealthatthevariationtrendoftheNCEP/NCARisstrongerthanthatoftheERA-40inthemid-to-lowertropospherefrom1958to2001.Throughsingularvaluedecomposition(SVD)analysis,thesummergeopotentialheightsat500hPafromtheERA-40arebetterthantheNCEP/NCARcounterpartsatinteractingwiththeprecipitationovertheEastAsianmonsoonregion.TheresultsindicatethattheNCEP/NCARinthemid-and-lowertropospheremayoverestimateinterdecadalchangesandshouldbeusedcautiouslytostudytherelationshipbetweentheWNPSHandprecipitationovetherEastAsiaMonsoonregionbeforethemid-1970s.
简介:Fifty-eightextratropicaltransition(ET)casesintheyears2000-2008,including2,021observations(at6-hourintervals),overthewesternNorthPacificareanalyzedusingthecyclonephasespace(CPS)method,inanefforttogetthecharacteristicsofthestructureevolutionandenvironmentalconditionsoftropicalcyclones(TCs)duringEToverthisarea.ClusteranalysisoftheCPSdatasetshowsthatstrongTCsaremorelikelytoundergoET.ETbeginswiththeincrementofthermalasymmetryinTCs,alongwiththegenerationandintensificationofanupper-levelcoldcore,andendswiththeoccurrenceofalower-levelcoldcore.ETlastsanaveragedurationofabout28hours.Dynamiccompositeanalysisoftheenvironmentalfieldofdifferentclustersshowsthat,ingeneral,whenTCsmovenorthward,theyaregraduallyembeddedinthewesterliesandgraduallytransformintoextratropicalcyclonesundertheinfluenceofthemid-andhigher-latitudebaroclinicsystems.AsforthoseTCswhichcompleteET,thereisalwaysmuchgreaterpotentialvorticitygradientinthenorthwestofthemandobviouswatervaportransportchannelsintheenvironment.
简介:DuringthedevelopingphaseofcentralPacificElNio(CPEN),morefrequentTCgenesisoverthenorthwestquadrantofthewesternNorthPacific(WNP)isattributedtothehorizontalshiftofenvironmentalvorticityfield.SuchanorthwestwardshiftresemblestheLaNiacomposite,eventhoughfactorsthatcausetheshiftdiffer(intheLaNiacasetherelativehumidityeffectiscrucial).GreaterreductionofTCfrequencyoverWNPhappenedduringthedecayingphaseofeasternPacificElNio(EPEN)thanCPEN,duetothedifferenceoftheanomalousPhilippineSeaanticyclonestrength.TheTCgenesisexhibitsanupward(downward)trendoverthenorthern(southern)partoftheWNP,whichislinkedtoSSTandassociatedcirculationchangesthroughlocalandremoteeffects.
简介:Theintraseasonaloscillation(ISO)oftheSouthChinaSea(SCS,105-120°E,5-20°N)convectionanditsinfluencesonthegenesisandtrackofthewesternNorthPacific(WNP)tropicalcyclones(TCs)wereexplored,basedonthedailyaverageofNCEP/NCARreanalysisdata,theOLRdataandthewesternNorthPacifictropicalcyclonebest-trackdatafrom1979to2008.ThemechanismoftheinfluencesofISOonTCmovementandthecorrespondinglarge-scalecirculationwerediscussedbyatrajectorymodel.Itwasfoundasfollows.(1)DuringtheSCSsummermonsoon,theSCSconvectionexhibitstheISOfeatureswithactivephasesalternatingwithinactivephases.Themonsooncirculationpatternsaresignificantlydifferentduringthesetwophases.WhentheSCSconvectionisactive(inactive),theSCS-WNPmonsoontroughstretcheseastward(retreatswestward)duetotheactivity(inactivity)ofSCSmonsoon,andtheWNPsubtropicalhighretreatseastward(stretcheswestward),whichenhances(suppresses)themonsooncirculation.(2)TheamountofTCgenesisintheactivephaseismuchmorethanthatintheinactivephase.AmajorityofTCsformwestof135°Eduringtheactivephasesbuteastof135°Eintheinactivephases.(3)TheTCsenteringtheareawestof135°Eandsouthof25°NwouldmovestraightintotheSCSintheactivephase,orrecurvenorthwardintheinactivephase.(4)Simulationresultsshowthatthesteeringflowassociatedwiththeactive(inactive)phasesisinfavorofstraight-moving(recurving)TCs.Meanwhile,theimpactsofthelocationsofTCgenesisonthecharacteristicsofTCtrackcannotbeignored.TCsthatoccurredfatherwestwardaremorelikelytomovestraightintotheSCSregion.
简介:以前的学习来到结论:基于南方亚洲人高度(SAH)的异例,在热带、副热带的区域上的100-hPageopotential高度,和100-hPa循环,我们能在长江山谷和诺思中国预言降水异例。测试它的有效性,一系列实验被设计了并且操作,它包括控制实验,敏感实验(它增加了异例进100-hPageopotential高度和风地),并且四合成的实验。基于象EPR-CF,EPRCD,EPR-HF,和EPR-HD那样的镇静的起始的领域试验,能在长江山谷和诺思中国复制洪水或干旱。它建议在热带、副热带的区域上的SAH,100-hPageopotential高度,和发行量的异例可以可能在二个区域暗示夏天降水异例。SAH,100-hPageopotential高度,和西南的异例流动在以前的时期的敏感实验结果表演是干旱或洪水的一个信号在长江山谷和诺思中国的下列夏天。并且它也是在二个区域在夏天降水异例上有影响的因素之一。100-hPageopotential高度并且SAH和西南流动的异常加强的积极异例将在诺思中国在长江山谷和干旱导致洪水;当100-hPageopotential高度并且SAH和西南流动的异常变弱的否定异例将在诺思中国在长江山谷和洪水导致干旱时。[出版摘要]
简介:Theroleofwintersea-iceintheLabradorSeaasaprecursorforprecipitationanomaliesoversoutheasternNorthAmericaandWesternEuropeinthefollowingspringisinvestigated.Ingeneralterms,astheseaiceincreases,theprecipitationalsoincreases.Inmoredetail,however,analysesindicatethatboththewintersea-iceandtheseasurfacetemperature(SST)anomaliesrelatedtoincreasesinwintersea-iceintheLabradorSeacanpersistintothefollowingspring.Thesefeaturesplayaforcingroleinthespringatmosphere,whichmaybethephysicalmechanismbehindtheobservationalrelationshipbetweenthewintersea-iceandspringprecipitationanomalies.TheoceanicforcingsinspringincludeArcticsea-iceanomaliesandSSTanomaliesinthetropicalPacificandhigh-latitudeNorthAtlantic.Multi-modelCoupledModelIntercomparisonProjectPhase5andAtmosphericModelIntercomparisonProjectsimulationresultsshowthattheatmosphericcirculationresponsetothecombinationofsea-iceandSSTissimilartothatobserved,whichsuggeststhattheoceanicforcingsareindeedthephysicalreasonfortheenhancedspringprecipitation.SensitivityexperimentsconductedusinganatmosphericgeneralcirculationmodelindicatethattheincreasesinprecipitationoversoutheasternNorthAmericaaremainlyattributabletotheeffectoftheSSTanomalies,whiletheincreasesoverWesternEuropearemainlyduetothesea-iceanomalies.AlthoughmodelsimulationsrevealthattheSSTanomaliesplaytheprimaryroleintheprecipitationanomaliesoversoutheasternNorthAmerica,theobservationalstatisticalanalysesindicatethattheareaofsea-iceintheLabradorSeaseemstobetheprecursorthatbestpredictsthespringprecipitationanomaly.
简介:以前的研究建议在北热带大西洋(NTA)上的春天SST异例影响热带气旋(TC)在在下列夏天和秋天的西方的诺思太平洋(WNP)上的活动。现在的学习表明在春天NTASST和后面的夏天秋天WNPTC开始频率之间的连接不是静止的。后面的夏天秋天WNPTC开始频率上的春天NTASST的影响是在前弱、不足道,却在以后强壮、重要,1980年代末。在1980年代末前,在热带中央太平洋的NTASST导致异例的SST异例是弱的,并且在WNP上的大气的循环的反应不是强壮的。作为结果,在春天NTASST和后面的夏天秋天WNPTC开始频率之间的连接在以前的时期是不足道的。在1980年代末以后,相反,NTASST异例通过大西洋和平的teleconnection导致显著热带中央和平的SST异例。热带中央和平的SST异例进一步为WNPTC开始导致有利条件,包括垂直运动,中间水平的相对湿度,和垂直的带的风砍。因此,在NTASST之间的连接和WNPTC开始频率在最近的时期是重要的。进一步的分析证明interdecadal在在春天NTASST之间的连接变化,后面的夏天秋天WNPTC开始频率可能与在NTA区域上的climatologicalSST变化有关。
简介:通过从CMIP3和CMIP5收集的联合模型模拟和设计的整体的分析,我们证明基本空间规模限制可能在气候模型预言和设计的有用另外的精炼不能在哪个下面是可能的下面存在。那限制在气候变量之中并且从区域变化到区域。我们证明在表面温度预言的无常(噪音)(在全球气候模型模拟的一个整体之中由传播代表了)通常在整个北美洲在1000km下面在水平规模超过整体平均数(信号),在那些规模暗示差的可预测性。更多的有限技巧为地区性的降水的可预测性被显示出。在这种情况中的整体传播趋于在2000km下面为规模超过或等于整体平均数。这些调查结果热点在预言地区性特定的未来气候异例的挑战,为特别,hydroclimatic影响例如干旱和湿。
简介:Fivesetsofmodelsensitivityexperimentsareconductedtoinvestigatetheinfluenceoftropicalcyclone(TC)genesislocationandatmosphericcirculationoninterannualvariabilityofTCintensityinthewesternNorthPacific(WNP).Ineachexperiment,bogusTCsareplacedatdifferentinitiallocations,andsimulationsareconductedwithidenticalinitialandboundaryconditions.Inthefirstthreeexperiments,thespecifiedatmosphericandSSTconditionsrepresentthemeanconditionsofElNio,LaNia,andneutralyears.TheothertwoexperimentsareconductedwiththespecifiedatmosphericconditionsofElNioandLaNiayearsbutwithSSTsexchanged.ThemodelresultssuggestthatTCsgeneratedinthesoutheasternWNPincurredmorefavorableenvironmentalconditionsfordevelopmentthanTCsgeneratedelsewhere.ThedifferentTCintensitiesbetweenElNioandLaNiayearsarecausedbydifferenceinTCgenesislocationandlow-levelvorticity(VOR).VORplaysasignificantroleintheintensitiesofTCswiththesamegenesislocationsbetweenElNioandLaNiayears.