简介:Permittivityofaseafoamlayerisveryimportantininvestigatingoceanbrightnesstemperaturemodel.Atmicrowavefrequency,theRayleighmethodisdevelopedtoestimatetheeffectivepermittivityoftheseafoamlayer.TosimplifythetediouscalculationofseafoameffectivepermittivityatLband(1.4GHz),Pade’approximationisadoptedtofittheseafoameffectivepermittivitycomputedbytheRayleighmethod.Withthisfittingformula,anewbrightnesstemperaturemodelofseafoamlayerdefinedbycertaingeophysicalparameters,suchasairvolumefraction(AVF),seasurfacetemperature(SST),seasurfacesalinity(SSS)andthicknessoffoamlayerd,isgiven.Furthermore,thesensitivitiesofthebrightnesstemperaturemodeltoSST,SSS,dandAVFofaseafoamlayeratLbandarediscussed.Thesensitivitiesarerankedfrommosttoleastintheorder:(1)d;(2)AVF;(3)SSS;(4)SST.ThisresultindicatesthatthemeasurementerrorsofdandAVFhavesignificantimpactsontheretrievalsofSSSandSST.Withtheexperimentalbrightnesstemperaturedata,theSSSandAFVareretrievedbycostfunction.
简介:Aseriesof96-htyphoontrackpredictionexperimentswerecarriedoutusingmediumrangeforecastingsystemofNMCbyaddingBOGUStyphoon(simplifiedasB-TC)intothefirstguessfieldortheanalysisfieldinordertoprovidelongertimetyphoontrackforecast.TheresultsshowthatT106L19couldprovideabetterforecasttotyphoontrackswhentheB-TCwasadded,especiallywhenthetyphoonvortexisevenweaker.ThesensitiveexperimentsonwheretoaddtheB-TCshowthattheresultsfromaddingtheB-TCintothefirstguessfieldarebetter.TheresultsalsoshowthattheinitializationsmoothestheB-TCalotandthiswillaffectthetyphoontrackprediction.
简介:ThefractalcharacteristicsofthecanopystructureofB.gvmnorrhizapopulationareinvestigatedbyfractaldimensionanalysisintheNationalShankouMangroveNatureReserve.The3-year-oldbrancheshaveboxdimensionsbetween1.22and1.55,showingthecomplexitydegreeofbranchingstructureandtheabilityofoccupyingandutilizingecologicalspace.ItmaybeconsideredthatfractaldimensionprovidesausefulindexforthestudyoflightutilizationefficienciesandgrowthprocessesofB.gymnorrhiza.Calculatedbyusingthetwo-surfacemethod,thefractaldimensionsforthecrownpatternofindividualswithagesof20to50yearsrangefrom2.21to2.54,indicatingthatthefillingdegreeoffoliagetoatreecrownisrelativelylowandB.gymnorrhizahasthepropertyofasunplant.Alongwiththeincreaseofagesofindividuals,thefillingdegreeoffoliagetoatreecrownchangesfromhightolow,andsodoesthefractaldimension.Theboxdimensionsobtainedfromthegrayscalecurvesofpopulationcanopyarebetween1.47and1.61.Thegreatertheboxdimension,themorelooselyorganizedthecanopyspatialstructure,andthemorethelightspots.Thecanopystructuralinformationandcomplexityofapopulationcanbeeffectivelycapturedbyboxdimensionsobtainedfromcanopygrayscalecurves.
简介:L波段雷达经过多年业务运行,故障频发,极易造成记录缺测或中断。如何在故障出现时完成观测任务,保证气象数据准确和完整,值班员的应急处置方法及时得当显得尤为重要。在总结经验的基础上,以西安泾河站2017年11月23日02时的一次L波段雷达系统突发性故障为例,从故障研判、仪器准备、数据观测、记录处理、编发报文等方面详细记录了单独测风应急观测业务流程和操作技巧,供同行参考。
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简介:AMW6.4earthquakeoccurredinL'Aquila,centralItalyat1:32:42(UTC),April6,2009.WequicklyobtainedthemomenttensorsolutionoftheearthquakebyinvertingthePwaveformsofbroadbandrecordingsfromtheglobalseismographicnetwork(GSN)stationsusingthequicktechniqueofmomenttensorinversion,andfurtherinferredthatthenodalplaneofstrike132°,dip53°andrake-103°istheseismogenicfault.