简介:速度体积处理(VVP)单个Doppler雷达的检索是能被用来获得许多风参数的一个有效方法。由于从方程的系数产生容易没被解决的一个性恶的矩阵的问题,然而,VVP方法没在操作足够地并且有效地被使用。在这篇论文,一个改进计划,基于原来的方法,SVVP(处理的步速度体积)被建议。改进算法通过一个逐步的过程检索风地的每组部件,它克服一个性恶的矩阵的问题,它当前限制VVP方法的申请。就算分析卷是很小的,在一个六参数的模型的变量能被检索。另外,在传统的方法存在的错误的来源和顺序被分析。改进方法被用于真实盒子,它证明它是柔韧的并且有能力获得本地对流系统的风地结构。它对学习暴风很有用。
简介:TheensemblebasedforecastsensitivitytoobservationmethodbyLiuandKalnayisappliedtotheSPEEDY-LETKFsystemtoestimatetheobservationimpactofthreetypesofsimulatedobservations.Theestimationresultsshowthatalltypesofobservationshavepositiveimpactonshort-rangeforecast.ThelargestimpactinNorthernHemisphereisproducedbyrawinsondes,followedbysatelliteretrievedprofilesandclouddriftwinddata,whichinSouthernHemisphereisproducedbysatelliteretrievedprofiles,rawinsondesandclouddriftwinddata.SatelliteretrievedprofilesinfluencemoreontheSouthernHemispherethanontheNorthernHemisphereduetofewobservationsfromrawinsondesintheSouthernHemisphere.Atthelevelof200to300hPa,thelargestimpactisattributedtowindobservationsfromrawinsondesandclouddriftwind.
简介:整体变换(et)方法被显示了在为适应观察推广提供指导有用。它在整体subspace用它的相应转变矩阵为各可能的推广预言预报错误变化减小。在这份报纸,一个新基于et的敏感(et)方法,以分析错误变化减小计算预报错误变化减小的坡度,被建议为可能的适应观察指定区域。et是ET的第一顺序近似;它要求就一个转变矩阵的一计算,增加计算效率(在计算费用的60%80%减小)。ETS坡度的明确的数学明确的表达被导出并且描述。ET和et方法为比较被用于飓风艾琳(2011)箱子和一个重降雨箱子。数字结果暗示ETS和et估计的敏感区域是类似的。然而,et是更有效的,特别地当分辨率更高,整体成员的数字更大时。
简介:Anoptimizationmethodisbasedtodesignasnowfallestimatemethodbyradarforoperationalsnowwarning,anderrorestimationisanalyzedthroughacaseofheavysnowonMarch4,2007.Threemodifiedschemesaredevelopedforerrorscausedbytemperaturechanges,snowflaketerminalvelocity,thedistancefromtheradarandcalculationmethods.Duetotheimprovements,thecorrelationcoefficientbetweentheestimatedsnowfallandtheobservationis0.66(exceedingthe99%confidencelevel),theaveragerelativeerrorisreducedto48.74%,andthemethodisabletoestimateweaksnowfallof0.3mm/handheavysnowfallabove5mm/h.Thecorrelationcoefficientis0.82betweentheestimatedsnowfallfromthestations50to100kmfromtheradarandtheobservation.Theimprovedeffectisweakwhentheinfluenceofthesnowflaketerminalvelocityisconsideredinthosethreeimprovementprograms,whichmayberelatedtotheuniformecho.Theradarestimateofsnow,whichisclassifiedbythedistancebetweenthesampleandtheradar,hasthemostobviouseffect:itcannotonlyincreasethedegreeofsimilarity,butalsoreducetheoverestimateandtheundervaluationoftheerrorcausedbythedistancebetweenthesampleandtheradar.Theimprovedalgorithmfurtherimprovestheaccuracyoftheestimate.Theaveragerelativeerrorsare31%and27%fortheheavysnowfallof1.6to2.5mm/handabove2.6mm/h,respectively,buttheradaroverestimatesthesnowfallunder1.5mm/handunderestimatesthesnowfallabove2.6mm/h.Radarechomaynotbesensitivetotheintensityofsnowfall,andtheconsistencyshownbytheerrorcanbeexploitedtoreviseandimprovetheestimationaccuracyofsnowforecastintheoperationalwork.
简介:系统介绍了利用SilviScan-3TM测量细胞结构、术材密度、微纤丝角和划分年轮界线的方法,并以祁连山青海云杉为例,分析青海云杉6个术材性质参数(年轮细胞直径、年轮细胞壁厚、年轮宽度、年轮密度、年轮微纤丝角、年轮弹性模量)与气候因子的关系,以期为利用多个树轮参数研究气候提供参考.结果表明:6个木材性质参数与月平均气温和月降水量都有显著相关的月份,但显著相关的时间段不同,并且微纤丝角和细胞结构参数中包含的气候信息强于常用的年轮宽度和年轮密度.SilviScan-3TM测量木材性质参数的优越性体现在:测量精度高、速度快,能在同一个试样上测量多个参数并能精确定年.
简介:TheLS-SVM(Leastsquaressupportvectormachine)methodispresentedtosetupamodeltoforecasttheoccurrenceofthunderstormsintheNanjingareabycombiningNCEPFNLOperationalGlobalAnalysisdataon1.0°×1.0°gridsandcloud-to-groundlightningdataobservedwithalightninglocationsysteminJiangsuprovinceduring2007-2008.Adatasetwith642samples,including195thunderstormsamplesand447non-thunderstormsamples,arerandomlydividedintotwogroups,one(having386samples)formodelingandtherestforindependentverification.ThepredictorsareatmosphericinstabilityparameterswhichcanbeobtainedfromtheNCEPdataandthepredictandistheoccurrenceofthunderstormsobservedbythelightninglocationsystem.Preliminaryapplicationstotheindependentsamplesfora6-hourforecastofthunderstormeventsshowthatthepredictioncorrectionrateofthismodelis78.26%,falsealarmrateis21.74%,andforecastingtechnicalscoreis0.61,allbetterthanthosefromeitherlinearregressionorartificialneuralnetwork.
简介:半含蓄的算法流行地被用来在数字模型处理重力的术语。在这份报纸,我们采用特征的方法在一个浅水模型用一个semi-Lagrangian移流计划直接在一个范围上为严肃波浪计算答案而不是半含蓄的方法,到避免昂贵的矩阵倒置。semi-Lagrangian计划的采纳为任何报纸数字使数字模型变为总是稳定,并且它节省中央处理器时间。为了说明特征的效率,抑制了插值侧面(CIP)方法,一些数字结果在Yin-Yang格子系统在一个范围上为理想化的测试用例被显示出。关键词特征CIP方法-浅水的模型-Yin-Yang格子-semi-Lagrangian计划-严肃波浪
简介:Atwo-stepmethodisemployedinthisstudytoretrieveverticalozoneprofilesusingscatteredmeasure-mentsfromthelimboftheatmosphere.ThecombinationoftheDifferentialOpticalAbsorptionSpectroscopy(DOAS)andtheMultiplicativeAlgebraicReconstructionTechnique(MART)isproposed.First,thelimbradiance,measuredoverarangeoftangentheights,isprocessedusingtheDOAStechniquetorecovertheeffectivecolumndensitiesofatmosphericozone.Second,theseeffectivecolumndensitiesalongthelinesofsight(LOSs)areinvertedusingtheMARTcoupledwithaforwardmodelSCIATRAN(radiativetransfermodelforSCIAMACHY)toderivetheozoneprofiles.ThismethodisappliedtoOpticalSpectrographandInfraRedImagerSystem(OSIRIS)radiance,usingthewavelengthwindows571-617nm.Verticalozoneprofilesbetween10and48kmarederivedwithaverticalresolutionof1km.Theresultsillustrateagoodagreementwiththecloud-freecoincidentSCanningImagingAbsorptionspectroMeterforAtmosphericCHartographY(SCIAMACHY)ozonemeasurements,withdeviationslessthan±10%(±5%foraltitudesfrom17to47km).Furthermore,sensitivitiesofretrievedozonetoaerosol,cloudparametersandNO2concentrationarealsoinvestigated.
简介:热带气旋是在更温暖的热带海洋发生并且在它的中心附近很快旋转并且同时沿着包围流动移动的一种强烈天气系统。大规模发行量在决定热带气旋的运动和驾驶流动的效果是在预报热带气旋运动和轨道的最高的优先级起一个主要作用,这通常被认出。这篇文章采用一个新方法导出驾驶流动并且选择一个典型转弯轨道盒子(台风丹,编码了9914)说明方法的有效性。一般途径是修改涡度,geostropical涡度和分叉,分别地,在非分叉的流函数,geoptential和速度潜力调查变化并且计算修改速度域决定驾驶流动。不同于在象风地或geopoential高度的加权的一般水准那样的常规使用的另外的方法,这个方法在环境地上有最不不利的效果并且能导出与暴风雨运动适合很好的合适的驾驶流动。与另外的内部、外部的forcings结合了,这个方法能在热带气旋轨道的预言有宽申请。
简介:19417号台风过程概况9417号热带风暴于8月15日生成,17日发展成台风,一直西行至台湾以东后开始北上,尔后转为西北行直逼我省沿海,于8月21日22时30分在我省瑞安市沿海登陆,路经温州、丽水、衢州等地市,于8月22日白天在江西省境内减弱为低气压。该台风强度强、范围大,登陆点离本市较近,对本市产生较严重的影响。全市普降暴雨、局部大暴雨,个别地方出现特大暴雨,大部分地区过程雨量超过100mm,诸暨南部与新昌、嵊县都在200mm以上,其中最大在嵊县金庭镇,达308mm,北部平原及嵊县盆地雨量较小,最大风力普遍8—10级(阵风)。
简介:Basedonfourtree-ringchronologieswhichwasanalyscdwithappropriatecollectionandaccuratedatinginthemiddleTibetanPlateau,anessentialprocedureonreconstructionofpastclimatehasbeenpointedoutinthispaper.First,theresponsefunctionofeachdendrochronologyhasbeenbuiltandusedtoestimatehowring-widthgrowthrespondstovariationsinmonthlyclimaticchange.Second,theclimatefactorswhichcouldbeproducedwithdifferenttree-ringserieshavebeenselected.Then,thetransferfunctionequation,includinganewsetoforthogonalvariables,canbeusedtoreconstructlocalpasttemperatureorprecipitation.Itshouldbeemphasizedthatpriorgrowthhasbeenconsideredintherelationshipbetweenclimatefactorandtree-ringchronology,Besides,somedifferentperiodsforcalibrationandverificationhavebeendivided.Andsomestatisticsandotherkindsofproxydatahavebeenadoptedastestapproaches.Asaresult,thevariationsofairtemperatureduringthelast600yearsandprecipitationduringthelast340yearswerereconstructedbycombiningthesametypesoftree-ringseriesinthemiddleTibet.
简介:ICSED(ImprovedClusterShadeEdgeDetection)algorithmandothervariousmethodstoaccuratelyandefficientlydetectedgesonsatellitedataarepresented.ErrorratecriterionisusedtostatisticallyevaluatetheperformancesofthesemethodsindetectingoceanicfeaturesforbothnoisefreeandnoisecontaminatedAVHRR(AdvancedVeryHighResolutionRadiometer)IRimagewithKuroshio.Also,practicalexperimentsindetectingtheeddyofKuroshiowiththesemethodsarecarriedoutforcomparison.ResultsshowthattheICSEDalgorithmhasmoreadvantagesthanothermethodsindetectingmesoscalefeaturesofocean.Finally,theeffectivenessofwindowsizeofICSEDmethodtooceanicfeaturesdetectionisquantitativelydiscussed.
简介:一个观察本地化计划被介绍进一基于整体三维变化(3DVar)吸收方法基于单个价值分解技术(SVD-En3DVar)到改善吸收技巧。一种逐点详述的分析技术在每观察的重量与增加在分析点和观察点之间的距离在哪个减少被采用。一套数字实验,模仿的Doppler雷达数据在被吸收进天气研究并且预报当模特儿,被设计测试计划。结果与在SVD-En3DVar,其任何一个都不包括这类观察本地化用全球的原版和本地补丁计划获得的那些相比。观察本地化计划不仅在失踪的数据的区域消除假分析增长,而且避免从本地补丁计划产生的不连续的分析领域。新计划提供更好的分析领域和更多合理短期降雨预报比原来的计划。从10架雷达吸收真实数据的另外的预报实验显示短期的降水预报技巧能被吸收雷达数据改进,观察本地化计划比另外的二个计划提供一张更好的预报。
简介:Dopplerweatherradarcanprovidethewindinformationsuchastheradialvelocity,andhasbecomeoneofthemostpowerfulmeansforstudiesofseveremesoscaleandmicroscaleweathersystems.Usuallytheradarobservationprovidesonlyplanepositionindicator(PPI)scanningdataandrangeheightindicator(RHI)scanningdata.andthismakessomeretrievalmethodsusingthree-dimensionalvolumescanningdataimpracticalinoperation.Inordertousethesedatamoreefficiently,aplaneassimilationretrieval(PAR)methodisdevelopedusingdataassimilationtechniqueonthePPIscanningplane.ThePARmethodistestedwiththeobservationdataofChineseAcademyofMeteorologicalSciences(CAMS)Dopplerweatherradarandtheresultisencouraging.