简介:Long-termintegrationsareconductedusingtheSpectralAtmosphericModel(referredtoasSAMIL),whichwasdevelopedintheLaboratoryforNumericalModelingforAtmosphericSciencesandGeophysicalFluidDynamics(LASG)intheInstituteofAtmosphericPhysics(IAP),withdifferentresolutionstoinves-tigatesensitivityoftheMadden-JulianOscillation(MJO)simulationstothemodel'sresolution(horizontalandvertical).Threeresolutionsofthemodel,R15L9,R42L9andR42L26,withidenticalphysicalprocesses,allproducedthebasicobservedfeaturesoftheMJO,includingthespatiotemporalspace-timespectraandeastwardpropagation.Nofundamentaldifferencesamongthesesimulationswerefound.ThisindicatesthatthemodelresolutionisnotadeterminingfactorforsimulatingtheMJO.Detaileddifferencesamongthesemodelingresultssuggest,however,thatmodelresolutioncansubstantiallyaffectthesimulatedMJOincertainaspects.Forinstance,atalowerhorizontalresolution,highfrequencydisturbanceswereweakerandthestructuresofthesimulatedMJOwerebetterdefinedtoacertainextent.AhigherverticalresolutionledtoamorerealisticspatiotemporalspectrumandspatialdistributionofMJOprecipitation.Meanwhile,increasingthemodel'sresolutionimprovedsimulationoftheclimatology.However,increasingtheresolutionshouldbebasedonimprovingthecumulusparameterizationscheme.
简介:一座大楼城市的流动上的密度的效果与RNGκ用一个CFD模型被调查-ɛ骚乱闭合计划。有不同的造的27个案例是密度参数(例如,大楼和街峡谷纵横比)数字地被模仿。当大楼的密度参数变化,不同流动政体出现。当街峡谷相对狭窄、高时,在垂直方向的二个相反旋转的旋涡被产生。沿着街的风速被大楼的长度主要影响。然而,以一座单个大楼的密度参数发现或概括街峡谷流动的特征是很困难的。这是因为复杂流动模式由于旋涡结构和旋涡数字的变化出现。平均卷的涡度大小是很好的指示物尽管有流动的强壮的相关性,在大楼的密度参数的变化上反映流动特征。平均卷的涡度大小是大楼的长度和街峡谷宽度的强壮的功能的多线性的回归表演。大楼的长度的增加减少街峡谷的涡度流动,当时,在街上,峡谷宽度增加的增加涡度。
简介:2004台风Aere的降水的结构的特征从测量国家航空学空间管理(NASA)的使命(TRMM)的热带降雨用高分辨率的数据被分析。台风的特征在它的发展的不同阶段变化,这被发现。分析降水分发的不对称的引起,从环境预言(NCEP)分析的国家中心的数据被用来计算水蒸汽流动向量的垂直积分。因为这个过程,结果显示出那,与成双台风的循环的唯一的现象一起,在东方台风的北方面的空气电流和它的南部的方面的西南的空气水流在搬运水起一个联合作用蒸汽。而且,它的运输效果在开发的不同阶段极大地变化,显示出为这台风进程的水来源的怪癖。由重降水和水蒸汽流动的一个最大值的区域描绘区域的台风传送对流的分布,以及在台风的发展的不同阶段的强壮的上升运动区域不同。水蒸汽流动和垂直运动的不一致的分发引起台风降水的不均匀的分发。
简介:BasedonChina’sobservationaldatain1951-1990,afterminimizingthepossiblebiasescausedbystationrelocationandurbanheatisland,thespatialandtemporaldistributionsoftrendsformaximumandminimumtemperaturesarestudied.Theresultsshowthatincreasingtrendsofmaximumtemperaturesareintheareaswestto95°E,andnorthtotheHuanghe(Yellow)River,whiledecreasingtrendsexistineasternChinasouthtotheYellowRiver.MinimumtemperaturesaregenerallyincreasingthroughoutChina,withdominantwarmingtrendsatthehigherlatitudes.Thisresultedinveryobviousdecreasingtrendsindiurnaltemperatureranges.Theperiodiccyclesareconsistentbetweenthemaximumandminimumtemperatures,butasymmetrictrendsareveryobvious.Thesignificantincreaseofminimum(nighttime)temperaturesreflectstheevidenceofenhancementofgreenhouseeffect.Furtheranalysisshowsthatthechangesofmaximumandminimumtemperaturesaremainlyrelatedtosunshinedurationandatmosphericwatervaporcontent.
简介:Byusingtheupper-winddatafromJuly1980toJune1983,thevariationsofthelow-frequencyoscillation(LFO)intheatmospherebeforeandduring1982ElNinohavebeeninvestigated.BeforetheElNino,theLFOpropagatesfromwesttoeastovertheequatoroftheEasternHemisphereandfromeasttowestover20°N.TheeastwardpropagatingLFOovertheequatorconsistsofzonalwavenumber1propagatingeastwardandzonalwavenumber2withacharacterofstationarywave.Theoscillationofzonalwavenumber2canmodulatetheoscillationstrength.AftertheonsetoftheElNino,thepropagatingdirectionsoftheLFOovertheequatorand20°NoftheEasternHemispherechangetobewestwardandeastward,respectively.TheLFOoverthewesternPacificweakensrapidlyandonecomingfrommiddleandhighlatitudespropagatestotheequator.Fromthephasecompositionsofstreamlinefieldsforthezonalwavenumber1ofequatorialwestwardpropa-gatirgLFO,itisfoundthattheatmosphericheatsourceintheequatoroftheeasternPacific(EEP)excitesaseriesoftheequatorialcyclonesandanticycloneswhichmovenorthwardandwestwardandformthewestwardpropagatingLFOovertheequator.Withthewavelengthof20000km,thiskindofequatorialwaveissimilartothemixingRossby-gravitywave.Initswestwardandnorthwardmovement,thecirculationinEastAsiaismodified.ThismaybethemechanismoftheinfluenceofElNinoontheclimateofChina.
简介:Thesimplelinearrelationshipbetweenclear-skyplanetaryandsurfacealbedocanbeadoptedforcertainaccuracy.Therearedifferentparameterizationschemesofatmosphericcorrectionfordifferentretrievalmodels.Inthispaper,severalrepresentativeretrievalmodelsarecomparedandtestedwithobservationaldatafromHEIhebasinFieldExperiment(HEIFE)inwesternChina.Someevaluationsandsuggestionsonimprovementareproposedformodelswhichwouldbemoreapplicabletoplateauandaridareas.
简介:Itispresentedthatthereisapumpingeffectatitsbaseinthedevelopmentprocessofacumulus.Inthestrongeststageofcumulusdevelopment,thepumpingismainlyproducedbythebuoyanceatthebase,andmaybetakenasthefirstapproximationoftheascendingspeedatthebase.Theresultsofnumericalcalculationsandsimulationsoffourobservedradarechoesshowthatasthefirstapproximation,theheightofair-masscumulusmaybesimulatedbyHaltinermodelintheabsenceofob-servedascendingspeedsatthebase,andtheHaltinermodelcanbecharacterizedbythesensitivityofthecumulusdevelopmenttothevirtualtemperatureexcessoverenvironmentatthebase.
简介:ThisworkinvestigatesthedistributionofhighwindsaboveBeaufortscale6intheoffshorezonesofChinausinghigh-resolutionsatellitemeasurements.AnumericalexperimentiscarriedoutinordertofindouttheeffectsofTaiwanIslandontheformationofstrongwinds.Theanalysisindicatesthatthedistributionofhighwindoccurrenceissimilartothatoftheaveragewindvelocityinwinter.Highwindstendtobeanchoredinspecialtopographicalregions,suchastheTaiwanStrait,theBashiChannelandthesoutheastcoastofVietnam.HighwindsoccurmuchmorefrequentlyoverthewarmerthanthecolderflankofKuroshiofrontasitmeandersfromTaiwantoJapan.Thefrequencyofhighwindsdecreasesdrasticallyinspring.TheTaiwanStraitmaintainsthelargesthighwindoccurrence.Besides,highwindsremainfrequentintheBashiChannel,thesoutheasttipofTaiwanIslandandthewarmerflankofKuroshiofront.Insummer,highwindsgenerallyoccurinfrequentlyexceptoverabroadregionoffthesoutheastcoastofVietnamnear10°Nandthefrequencytheredecreasesfromsouthwesttonortheast.HighwindsaroundTaiwanIslandpresentnearaxisymmetricdistributionwithlargerfrequencyalongsoutheast-northwestdirectionandsmallerfrequencyalongsouthwest-northeastdirection.Thedominantdirectionofhighwindsexhibitsacounterclockwisecirculationsurroundingtheisland.Thefrequencyofhighwindsincreasesrapidlyinautumnandalmostrepeatsthedistributionthatappearsinwinter.ThesimulationresultssuggestthattheeffectsofTaiwanIslandtopographyonhighwindsvarywithseasons.Inwinter,topographyisthemajorcauseofhighwindsinthesurroundingoceaniczones.HighwindsinbothTaiwanStraitandthesoutheastcorneroftheislanddisappearandthefrequencydecreasesgraduallyfromsouthtonorthwhentheterrainisremoved.However,insummer,highwindfrequencyderivedfromtwosimulationswithandwithoutterrainisalmostidentical.Weattributethisphenomenontothefactorswhicharerespon
简介:Abaroclinicsemi-geostrophicmodelwithevaporation-windfeedbackmechanism(EWFM)andCISKisestablished,twonon-dimensionalparametersaandηareintroducedtorepresentEWFMandCISK,respectively.Analyticsolutionsofthemodelsystemareobtained,dynamicsanalysesandthemodelatmospherecalculationsfurtherconfirmthatEWFMandCISKareveryimportantphysicalprocessesinleadingtothelow-frequencyoscillationsinthetropics.
简介:ThedistributionofmonthlymeanerrorofNMCmodelforecastsanditsseasonalvariationareinvesti-gated.Theratioofmonthlymeanerrortostandarddeviationisusedheretofindoutthattheregionwhereacorrectionofsystematicerrorisneededandappropriateismainlyinlowlatitudes.Theimprovement,afterthemodel’sverticalresolutionandsomephysicalparameterswerechangedfromApril1985,isinvestigated,andtheNMCoperationalmodelforecastshavealsocomparedwiththoseofECMWF.
简介:采用哈巴河县观测站1961—2008年逐月平均气温、平均最高、平均最低气温资料.利用一元回归和R/S方法,分析了哈巴河县四季和年平均气温、年平均最高气温、年平均最低气温的变化特征。结果表明:近48年以来,哈巴河县冬、夏、秋季平均气温及全年平均气温序列均表现为升温的趋势,其中冬季升温最为明显:四季和年平均最高和最低气温近48年来也呈上升趋势.并且四季和年平均最低气温的上升趋势比四季和年平均最高气温的上升趋势显著。经R/S分析表明,未来四季中夏、秋、冬季及年平均气温仍呈上升趋势且持续时间较长,而春季气温上升趋势不明显;四季和年平均最高、最低气温未来上升的趋势也将继续存在,且最低气温的持续性比最高气温的持续性长,夏、秋两季最低气温升温趋势相对其他两季较为明显,而夏、冬两季的最高气温的升温趋势相对其他两季较为明显。总之.近48年来哈巴河县气温总体变化趋势存在明显的hurst现象.未来这种现象也仍将持续。
简介:BasedontheNCEP/NCARreanalysisdataandtheobservedprecipitationdatainthesouthofChinafrom1958to2000,theimpactof30to60dayoscillationofatmosphericheatsourcesonthedroughtandfloodeventsinJuneinthesouthofChinaisdiscussed.Duringtheflood(drought)events,thereexistsananomalouslow-frequencyanticyclone(cyclone)atthelowlevelofthetroposphereovertheSouthChinaSeaandthenorthwesternPacific,accompaniedwithanomalouslow-frequencyheatsinks(heatsources),whilethereexistsananomalouslow-frequencycyclone(anticyclone)withanomalousheatsources(sinks)overtheareafromthesouthofChinatothesouthofJapan.Onaverage,thephaseevolutionofthelow-frequencyindroughteventsis7to11daysaheadofthatinfloodeventsinMaytoJuneinthesouthofChina.Infloodevents,low-frequencyheatsourcesandcyclonesarepropagatednorthwardfromthesouthernSouthChinaSea,northwestwardfromthewarmpoolofthewesternPacificandwestwardfromthenorthwesternPacificaround140°E,whichhaveveryimportantimpactontheabundantrainfallinJuneinthesouthofChina.However,indroughtevents,thenorthwardpropagationsofthelow-frequencyheatsourcesandcyclonesfromtheSouthChinaSeaanditsvicinityareratherlatecomparedwiththoseinfloodevents,andthereisnoobviouswestwardpropagationoftheheatsourcesfromthenorthwesternPacific.Thetimingofthelow-frequencyheatsourcepropagationhasremarkableimpactontheJunerainfallinthesouthofChina.
简介:热带降雨测量的影响结构和intraseasonal摆动(ISO)的内在的物理上的使命(TRMM)降水产品与美国国家航空学和观察系统模型版本3的空格管理戈达德土(GEOS-3)被调查数据吸收系统(DAS)。在1998夏天的强壮的ISO阶段显然位于亚洲季风区域和东方赤道的和平的区域。当向东北的繁殖是在30点的突出的ISO到超过10的60天的摆动时,东方繁殖是为在20点的热带ISO的一个主导的特征到30天的摆动