简介:AWRF-Chemmodelincludingacomprehensivegas-phasenitrogenchemistrymodulewasusedtosimulateaseveredusteventappearingintheeasternChinaon19-25March,2002.ThemodelingresultwellreproducedPM10concentrationsinvariousdistancesfromthedustsourcesandthetransportpathwayoftheduststrom.TheresultsshowedthatboththeconcentrationsandthedrydepositionfluxesofPM10increasedovertheChinaseasduringthedusteventfollowingthepassageofacoldfrontsystem.ThemaximumfluxesofPM10intheYellowSeaandtheEastChinaSeaduringthedusteventwere5.5and8.4timesofthosebeforetheevent,respectively.However,thetemporalvariationsofthedrydepositionfluxesofparticulateinorganicnitrogendifferedovertheYellowSeafromthoseovertheEastChinaSea.NitrateandammoniuminthewholenorthernChinarapidlydecreasedbecauseoftheintrusionofdust-loadedairon19March.ThedustplumearrivedintheYellowSeaon20March,decreasingtheparticulateinorganicnitrogeninmassconcentrationaccordingly.TheminimumdrydepositionfluxesofnitrateandammoniumintheYellowSeawereabout3/5and1/6ofthosebeforethedustarrival,respectively.Incontrast,whenthedustplumecrossedovertheYangtzeDeltaarea,itbecameabundantinnitrateandammoniumandincreasedtheconcentrationsanddrydepositionfluxesofparticulateinorganicnitrogenovertheEastChinaSea,wherethemaximumdrydepositionfluxesofnitrateandammoniumincreasedapproximatelyby4.1and2.6timesofthosepriortothedustarrival.
简介:天气研究预报模型(WRF)与高分辨率和NCEP1?设置了???ㄠ???????????????????????????è
简介:SignificantchangeshaveoccurredintheAntarcticPeninsula(AP)includingwarmertemperatures,acceleratedmeltingofglaciers,andbreakupoficeshelves.ThisstudyusestheWeatherResearchandForecastingmodel(WRF)forcedbytheCommunityClimateSystemModel4(CCSM)simulationstostudyfoehnwindwarminginAP.Wea-thersystemsresponsibleforgeneratingthefoehneventsaretwocyclonicsystemsthatmovetowardand/orcrossoverAP.WRFsimulatesthemovementofcyclonicsystemsandtheresultingfoehnwindwarmingthatisabsentinCCSM.ItisfoundthatthewarmingextentalongatransectacrossthecentralAPtowardLarsenCIceShelf(LCIS)variesduringthesimulationperiodandthemaximumwarmingmovesfromnearthebaseofleewardslopestoover40kmawayextendingtowardtheattachedLCIS.Ouranalysissuggeststhatthefoehnwindwarmingisnegativelycorrelatedwiththeincomingairtemperatureandthemountaintoptemperatureduringperiodswithoutsignificantprecipitation,inwhichisentropicdrawdownisthedominantheatingmechanism.Ontheotherhand,whensignificantprecipitationoccursalongthewindwardsideofAP,latentheatingisthemajorheatingmechanismevidencedbypositiverelationsbetweenthefoehnwindwarmingand1)incomingairtemperature,2)windwardprecipitation,and3)latentheating.Foehnwindwarmingcausedbyisentropicdrawdownalsotendstobestrongerthanthatcausedbylatentheating.ComparisonofWRFsimulationsforcedbyoriginalandcorrectedCCSMdataindicatesthatfoehnwindwarmingisstrongerintheoriginalCCSMforcedsimulationwhennosignificantwindwardprecipitationispresent.Thefoehnwindwarmingbecomesweakerinbothsimulationswhenthereissignificantwindwardprecipitation.Thissuggeststhatmodel’sabilitytoresolvethefoehnwarmingvarieswiththeforcingdata,buttheprecipitationimpactontheleewardwarmingisconsistent.
简介:Twolandsurfacemodels,CommunityLandModel(CLM3.5)andNOAHmodel,havebeencoupledtotheWeatherResearchandForecasting(WRF)modelandbeenusedtosimulatetheprecipitation,temperature,andcirculationfields,respectively,overeasternChinainatypicalfloodyear(1998).Thepurposeofthisstudyistorevealtheeffectsoflandsurfacechangesonregionalclimatemodeling.ComparisonsofsimulatedresultsandobservationdataindicatethatchangesinlandsurfaceprocesseshavesignificantimpactonspatialandtemporaldistributionofprecipitationandtemperaturepatternsineasternChina.CouplingoftheCLM3.5totheWRFmodel(experimentWRF-C)substantiallyimprovesthesimulationresultsovereasternChinarelativetoanolderversionofWRFcoupledtotheNOAH-LSM(experimentWRF-N).ItisfoundthatthesimulationofthespatialpatternofsummerprecipitationinWRF-CisbetterthaninWRF-N.WRF-Calsosignificantlyreducesthesummerpositivebiasofsurfaceairtemperature,anditssimulatedsurfaceairtemperaturematchesmorecloselytoobservationsthanWRF-Ndoes,whichisassociatedwithlowersensibleheatfluxesandhigherlatentheatfluxesinWRF-C.
简介:开展了基于嵌套的全球模式MIROC和区域气候模式WRF的动力降尺度模拟试验,检验该模式对中国气候的模拟性能,得到以下结论:全球气候模式MIROC和WRF都能较好地模拟出中国年平均地表气温(下文简称气温)分布。WRF模式对气温场的描述更为细致,模拟出了四川盆地高温和中国最北方区域的低温。两个模式总体上对南方降水模拟好于北方地区,东部地区好于西部地区。MIROC模式模拟的年平均和各季节降水与观测的空间相关系数在0.79~0.83之间,表明它对降水的模拟较好。WRF模式模拟的降水空间分布好于MIROC模式。MIROC模式在青藏高原东南侧存在虚假降水中心,WRF能有效改进该地区降水的模拟。两个模式对年平均气温和降水年际变率的模拟能力均较差,WRF模式相对MIROC模式有一定改进。
简介:利用WRF模式的5种云微物理方案对华西地区一次秋雨过程(2011年9月13—20日)进行了模拟,分析不同云微物理方案对华西秋雨的模拟能力,并对降水模拟差异的可能原因进行分析。结果表明:WRF模式的5种云微物理方案对华西秋雨均具有一定的模拟能力,可模拟出华西秋雨的夜雨特征,但Kessler方案模拟的降水落区偏小且降水强度偏弱,而Lin方案模拟的降水强度则偏强;相对来说,Ferrier和WSM3方案对华西秋雨主要降水过程的模拟效果较好。对比WRF模式5种不同云微物理方案对华西秋雨过程的模拟可知,各方案模拟的区域降水强度与WRF模式模拟的上升运动的强弱存在较好的一致性。
简介:Themaximumheightoftheconvectiveboundarylayer(CBL)overtheTaklimakanDesertcanexceed5000mduringsummerandplaysacrucialroleintheregionalcirculationandweather.WecombinedtheWeatherResearchandForecastingLargeEddySimulation(WRF-LES)withdatafromGlobalPositioningSystem(GPS)radiosondesandfromeddycovariancestationstoevaluatetheperformanceoftheWRF-LESinsimulatingthecharacteristicsofthedeepCBLoverthecentralTaklimakanDesert.ThemodelreproducedtheevolutionoftheCBLprocessesreasonablywell,butthesimulationsgeneratedwarmerandmoisterconditionsthantheobservationasaresultoftheover-predictionofsurfacefluxesandlarge-scaleadvection.Furthersimulationswereperformedwithmultipleconfigurationsandsensitivitytests.Thesensitivitytestsforthelateralboundaryconditions(LBCs)showedthatthemodelresultsaresensitivetochangesinthetimeresolutionanddomainsizeofthespecifiedLBCs.AlargerdomainsizevariesthedistanceoftheareaofinterestfromtheLBCsandreducestheinfluenceoflargeforecasterrorsneartheLBCs.ComparingthemodelresultsusingtheoriginalparameterizationofsensibleheatfluxwiththeNoahlandsurfaceschemeandthoseofthesensitivityexperimentsshowedthatthedesertCBLissensitivetothesensibleheatfluxproducedbythelandsurfaceschemeduringdaytimeinsummer.Areductioninthesensibleheatfluxcancorrectoverestimatesofthepotentialtemperatureprofile.However,increasingthesensibleheatfluxsignificantlyreducesthetotaltimeneededtoincreasetheCBLtoarelativelylowaltitude(<3km)inthemiddleandinitialstagesofthedevelopmentoftheCBLratherthanproducingahigherCBLinthelaterstages.
简介:Aseriesofnumericalsimulationsisconductedtounderstandtheformation,evolution,anddissipationofanadvectionfogeventoverShanghaiPudongInternationalAirport(ZSPD)withtheWeatherResearchandForecasting(WRF)model.UsingthecurrentoperationalsettingsattheMeteorologicalCenterofEastChinaAirTrafficManagementBureau,theWRFmodelsuccessfullypredictsthefogeventatZSPD.Additionalnumericalexperimentsareperformedtoexaminethephysicalprocessesassociatedwiththefogevent.Theresultsindicatethatpredictionofthisparticularfogeventissensitivetomicrophysicalschemesforthetimeoffogdissipationbutnotforthetimeoffogonset.Thesimulatedtimingofthearrivalanddissipationofthefog,aswellastheclouddistribution,issubstantiallysensitivetotheplanetaryboundarylayerandradiation(bothlongwaveandshortwave)processes.Moreover,varyingforecastleadtimesalsoproducesdifferentsimulationresultsforthefogeventregardingitsonsetandduration,suggestingatrade-offbetweenmoreaccurateinitialconditionsandaproperforecastleadtimethatallowsmodelphysicalprocessestospinupadequatelyduringthefogsimulation.TheoveralloutcomesfromthisstudyimplythatthecomplexityofphysicalprocessesandtheirinteractionswithintheWRFmodelduringfogevolutionanddissipationisakeyareaoffutureresearch.
简介:利用东北区域实况24h累积降水资料,应用与国家气象中心建设并使用的全国业务区域模式统一检验平台一致的检验方法,采用WRFV3.3.1模式对东北地区2012年4次大暴雨过程、两次暴雪过程的预报效果进行了客观检验及统计分析,并与JAPAN模式和T639模式进行对比分析,结合主观检验,对WRF模式在东北地区的预报性能进行评估。结果表明:2012年东北地区6次强降水过程WRF模式预报效果与JAPAN模式、T639模式基本相当,即有较稳定且较高水平的预报能力,加之其中尺度模式较高的时空分辨率,因此在天气预报领域有重要的使用和研究价值。2012年东北地区6次重大降水过程,WRF模式对降水的位置及时间演变趋势预报均较好,对主降水带的位置及强度预报效果总体一般,在对主降水带位置与强度预报效果较好的前提下,其对于暴雨中心的位置预报效果也较好。与T639模式和JAPAN模式相比,WRF中尺度模式的主降水带形态刻画更细致,对强降水中心的位置和范围预报较明确,且在主降水带位置与强度预报效果较好的前提下较可靠,WRF中尺度模式的这一优点,对目前精细化预报有重要意义;客观检验并不能完全说明模式的预报效果,WRF模式预报效果的检验和模式预报水平的说明,必须结合主观检验,且需从多角度进行全面考察;WRF模式对1215号台风路径及台风暴雨过程预报均与实况基本吻合(尤其是36h和24h预报),说明WRF中尺度模式对台风系统及其诱发的暴雨过程有较好的预报能力。
简介:Theresultsfromahybridapproachthatcombinesamesoscalemeteorologicalmodelwithadiagnosticmodeltoproducehigh-resolutionwindfieldsincomplexcoastaltopographyareevaluated.Thediagnosticwindmodel(CaliforniaMeteorologicalModel,CALMET)with100-mhorizontalspacingwasdrivenwithoutputsfromtheWeatherResearchandForecasting(WRF)modeltoobtainnear-surfacewindsforthe1-yearperiodfrom12September2003to11September2004.Resultswerecomparedwithwindobservationsatfoursites.Traditionalstatisticalscores,includingcorrelationcoefficients,standarddeviations(SDs)andmeanabsoluteerrors(MAEs),indicatethatthewindestimatesfromtheWRF/CALMETmodelingsystemareproducedreasonablywell.Thecorrelationcoefficientsarerelativelylarge,rangingfrom0.5to0.7forthezonalwindcomponentandfrom0.75to0.85forthemeridionalwindcomponent.MAEsforwindspeedrangefrom1.5to2.0ms-1at10metersabovegroundlevel(AGL)andfrom2.0to2.5ms-1at60mAGL.MAEsforwinddirectionrangefrom30to40degreesatbothlevels.AspectraldecompositionofthetimeseriesofwindspeedshowspositiveimpactsofCALMETinimprovingthemesoscalewinds.Moreover,combiningtheCALMETmodelwithWRFsignificantlyimprovesthespatialvariabilityofthesimulatedwindfields.ItcanbeconcludedthattheWRF/CALMETmodelingsystemiscapableofprovidingadetailednear-surfacewindfield,butthephysicsinthediagnosticCALMETmodelneedstobefurtherimproved.
简介:检验评估是数值天气预报的一个重要组成部分,评估结果是模式改进及其产品解释应用的重要依据。利用全省1500多个包括区域自动站在内的站点观测资料,采用要素的空间分布、时间演变和统计检验3种方法评价了WRF模式对浙江省2011年夏季(6—8月)降水和温度的整体预报性能;在此基础上,进一步对比分析了不同湿过程参数化方案对梅雨典型过程的预报效果,探讨了不同微物理参数化方案和积云参数化方案对模式预报降水的影响。结果表明,WRF模式能基本预报出降水和气温的细致空间分布形态及整体演变趋势,对于主要降水落区、高温区具有较好的指示性;就浙江省区域平均而言,在实况出现较大降水期间模式预报误差较小,而在实况出现小到中雨期间误差较大,主要表现为降水量的高估和气温的低估;模式湿过程中积云参数化方案对降水影响明显,它可以导致整体雨带偏移,采用Betts-Miller-Janjic积云对流参数化方案的预报降水更接近实况。这些信息对改进模式的精细化预报能力和高分辨率数值产品的解释应用具有一定的参考作用。
简介:为解析大气污染物与气象的双向反馈机制及其对气象和环境的影响,建立基于Mie散射理论的气溶胶—光学性质模块,研制气象-化学双向耦合器,以嵌套网格空气质量预报模式NAQPMS(NestedAirQualityPredictionModelingSystem)为基础,建立了NAQPMS和中尺度气象模式WRF(WeatherResearchandForecastingModel)的双向耦合模式(WRF-NAQPMS)。利用此模式数值模拟了2013年9月27日至10月1日的北京-天津-河北地区一次秋季严重灰霾过程。结果表明,考虑气溶胶辐射反馈的双向耦合模式模拟的气象要素和细颗粒物(PM2.5)浓度与观测结果更为一致。灰霾期间,气溶胶直接辐射效应显著改变了边界层气象要素,北京-天津-河北地区地面接收的太阳短波辐射减少25%,2m高度的温度平均下降1℃,湍流动能下降20%,10m高度的风速降低超过0.2m/s,边界层高度下降25%,使得边界层大气更加静稳,进而造成了重污染地区污染进一步加剧,如石家庄近地面细颗粒物浓度增加可达30%。分析表明灰霾与边界层气象要素之间存在一种正反馈机制,采用该机制的双向耦合模式有利于准确模拟和预报灰霾污染过程。