简介:A2m~3isothermalcloudchambermainlyforicenucleationresearchisdescribedinthispaper.Itsstructure,attachedinstrumentsandexperimentalproceduresarealsopresented.TheexperimentsofdeterminingtheicenucleieffectivenessfortheAgl-containingaerosolsproducedbythreeformulationshavebeenconductedandtheresultshavebeencomparedwiththoseoftheCSU960-literisothermalcloudchamber.Allexperimentalresultsshowthatthechamberhasadvantagesofstableperformanceandreproducibility.Itwouldbeexpectedtobecomeausefulexperimentalfacilityforicenucleationresearch.
简介:Thedaily1°×1°dataoftheAviation(AVN)model,theblackbodytemperature(TBB)dataofcloudtop,andcloudimagesbygeostationarymeteorologicalsatellite(GMS)areusedtoidentifyadew-pointfrontneartheperipheryofthewesternPacificsubtropicalhigh(WPSH).Theresultsclearlydemonstratetheexistenceofthedew-pointfront,anditsthermodynamicanddynamicstructuralcharacteristicsareanalyzedindetail.Thedew-pointfrontisatransitionalbeltbetweenthemoistsouthwestmonsoonflowandthedryadiabaticsinkingflowneartheWPSH,manifestedbyalargehorizontalmoisturegradientinthemid-lowertroposphereandconjugatedwiththemei-yufronttoformapredominantdouble-frontstructureassociatedwithintenserainfallinthemei-yuperiod.Themei-yufrontislocatedbetween30°and35°N,verticallyextendsfromthegroundleveltotheupperlevelandshiftsnorthward.Thedew-pointfrontistothesouthofthemei-ynfrontandliesupagainsttheperipheryoftheWPSH.Generally,itislocatedbetween850hPaand500hPa.Onthedew-pointfrontside,thesouthwesterlyprevailsatthelowerlevelandthenortheasterlyattheupperlevel;thiswinddistributionisdifferentfromthatonthemei-yufrontside.Verticalascendingmotionexistsbetweenthetwofronts,andtherearedescendingmotionsonthenorthsideofthemei-yufrontandonthesouthsideofthedew-pointfront,whichformasecondarycirculation.Thedynamicsofthedoublefrontsalsohavesomeinterestingfeatures.Atthelowerlevel,positiveverticalvorticityandobviousconvergencebetweenthetwofrontsareclearlyidentified.Atthemid-lowerlevel,negativelocalchangeofthedivergence(correspondingtoincreasingconvergence)isoftenembeddedinthetwofrontsoragainstthemei-yufront.Mostcloudclustersoccurbetweenthetwofrontsandpropagatedownstreaminawave-likemanner.
简介:Thispaperpresentsahigh-resolutionsimulationofaremarkablepolarlowobservedovertheSeaofJapanon21January1997byusinga5-kmmeshnon-hydrostaticmodelMRI-NHM(MeteorologicalResearchInstituteNon-HydrostaticModel).A24-hoursimulationstartingfrom0000UTC21January1997successfullyreproducedtheobservedfeaturesofthepolarlowsuchasthewrappingofwesternpartofaninitialEWorientationvortex,thespiral-shapedbands,thecloud-free'eye',andthewarmcorestructureatitsmaturestage.The'eye'ofthesimulatedpolarlowwasrelativelydry,andwasassociatedwithastrongdowndraft.Athermodynamicbudgetanalysisindicatesthatthe'warmcore'inthe'eye'regionwasmainlycausedbytheadiabaticwarmingassociatedwiththedowndraft.Therelationshipamongthecondensationaldiabaticheating,theverticalvelocity,theconvergenceofthemoistureflux,andthecirculationaveragedwithina50km×50kmsquareareaaroundthepolarlowcentershowsthattheyformapositivefeedbackloop,andthisloopisnotinconsistentwiththeCISK(ConditionalInstabilityoftheSecondKind)mechanismduringthedevelopingstageofthepolarlow.
简介:利用HadCM2模式的模拟结果,比较了温室气体排放综合效果相当于CO2浓度逐年递增1%和0.5%两种不同情景下,中国区域21世纪地面气温和降水量的变化趋势.结果表明,随着温室气体浓度的持续增加,中国地面气温也持续升高.到21世纪末期,地面气温在上述两种排放情景下可分别升高约5℃和3℃.两种排放情景的增温趋势对比表明:即使从1990年开始温室气体等效排放逐年递增率减少一半,增温仍然很明显;直到21世纪中期,才能显示出减少温室气体排放量对减缓增温趋势的效果.降水量的年际变化较大,但随着温室气体浓度的持续增加,降水量总的趋势也是增加的.减排温室气体对降水量变化趋势的影响与地面气温相似.此外,地面气温增量和降水量变化百分率均显示出明显的季节变化,地面气温增量在秋、冬季较大而在春、夏季较小,降水变化百分率在夏、秋季较小而在冬、春季较大.
简介:ThedevelopmentofthefogdetectorwasinvestedbytheStatePlanningCommissionandstartedinJuly1997.Theprototype'scalibrationandtestwasconductedin1999.Thereafterthedetectorwasimprovedinthefollowingrespects:Hardware:Inordertoreducetheeffectsofthebackground,thetransmitterandreceiverunitsweredesignedtobedownwards.Ahigh-powerGaAsLEDisusedforthelightsourcesandforincreasingtransmittingpower.Theintensityofthelightismonitoredandstabilizedbyaspecialcircuitinthetransmitterunit,whichreceivesapartoftheemittedlightbyaPIN
简介:CAWS600型自动气象站于2001年9月获得了中国气象局颁发的使用许可证,这是中国气象科学研究院获得的第一个科研成果转化成产品的科研项目,这使我们取得了良好的社会效益和经济效益。CAWS600系列自动气象站及其相应的传感器如温度传感器、温湿度传感器、辐射仪器仪表和其它各种传感器等,随同CAWS600型自动站先后定型,并取得了使用许可证。现已推向市场且占有了一定的市场份额。几年来,我们的销量与销售领域不断扩大,2000年以来,又增加了可测能见度的新型机场自动气象站,随时确定方位的船舶自动气象站,可测不同高度风参数和温度参数(即测