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:摘要利用在线耦合的三维大气化学传输模式WRF-Chem模拟了冬季东亚地区的气溶胶辐射反馈情况。该模式的模拟结果中,温度、相对湿度、风速等值都和地面观测有较好的对应关系,可较好地反应该区域的气象要素特征。针对大气污染物的模拟,结果可见PM2.5的高值区主要集中在中国东部地区,包括长江中下游平原和华北平原,另外四川盆地的颗粒物浓度也较高。本研究还对比了开关气溶胶辐射反馈的两个数值实验,发现东亚地区由于PM2.5导致的地表短波辐射接收量减少了约20-45W/m2,其中降幅最大的是京津冀区域、四川盆地及华中平原区,这与颗粒物浓度的高值区是相对应的。由于气溶胶气候效应导致的温度、相对湿度变化分别达到-0.6℃和6%,增加的湿度导致颗粒物的吸湿增长,其质量浓度会对应升高。该结果定量描述了该地区由于气溶胶辐射反馈造成的近地面温度湿度变化,并分析了其可能存在的正反馈机制。
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:为了判别MM5和WRF两种模式下高空气象数据模拟结果的差异性和可替代性,系统比较了两个中尺度气象数值模式的差异,应用WRF和MM5分别模拟了2010年北京某参照地点高空气象场的温度、露点温度、风场和相对湿度,对比分析了两种气象模式模拟结果的垂直廓线差异和时间变化差异。结果表明,除近地层和约8000m以上的高层模拟值略有偏差外,WRF和MM5模拟的各气象要素的垂直廓线变化一致,吻合度非常好。两模型对气象数据模拟结果的相关系数达89%-99%。WRF和MM5模拟的各气象要素的日变化趋势也基本一致,除对风速和风向模拟值间的相关系数低于81%外,温度、露点温度和相对湿度模拟值间的相关系数达84%~98%。因此,两模式可相互替代用于环境影响评价高空气象数据的模拟。