简介:Radio-frequencyinterference(RFI)affectsgreatlythequalityofthedataandretrievalproductsfromspace-bornemicrowaveradiometry.AnalysisoftheAdvancedMicrowaveScanningRadiometerontheEarthObservingSystem(AMSR-E)AquasatelliteobservationsrevealsverystrongandwidespreadRFIcontam-inationsontheC-andX-banddata.Fortunately,thestrongandmoderateRFIsignalscanbeeasilyidentifiedusinganindexonobservedbrightnesstemperaturespectrum.ItistheweakRFIthatisdiffi-culttobeseparatedfromthenaturesurfaceemission.Inthisstudy,anewalgorithmisproposedforRFIdetectionandcorrection.Thesimulatedbrightnesstemperatureisusedasabackgroundsignal(B)andadepartureoftheobservationfromthebackground(O-B)isutilizedfordetectionofRFI.ItisfoundthattheO-Bdeparturecanresultfromeitheranaturalevent(e.g.,precipitationorflooding)oranRFIsignal.AseparationbetweenthenatureeventandRFIisfurtherrealizedbasedonthescatteringindex(SI).ApositiveSIindexandlowbrightnesstemperaturesathighfrequenciesindicateprecipitation.IntheRFIcorrection,arelationshipbetweenAMSR-Emeasurementsat10.65GHzandthoseat18.7or6.925GHzisfirstdevelopedusingtheAMSR-EtrainingdatasetsunderRFI-freeconditions.ContaminationofAMSR-Emeasurementsat10.65GHzisthenpredictedfromtheRFI-freemeasurementsat18.7or6.925GHzusingthisrelationship.ItisshownthatAMSR-EmeasurementswiththeRFI-correctionalgorithmhavebetteragreementwithsimulationsinavarietyofsurfaceconditions.
简介:用被动微波辐射计的陆地检索对在陆地亮度温度的小变化敏感。因此,无线电频率干扰(射频干扰)发信号发出从人造微波放射传输器能在陆地检索导致大错误。在隧道能遥远地污染的C乐队和X乐队的射频干扰察觉到大小,经历了与扫描辐射计(AMSR-E)和WindSat传感器的先进微波。在这个工作,射频干扰察觉的应用程序和在从AMSR-E大小使用检索地球物理的参数的一间全面套房的修正算法,一个维的变化检索(1-DVAR)方法被描述。结果显示检索参数的值例如陆地皮肤温度(LST),在射频干扰污染的这些区域上比从全球数据吸收系统(GDAS)的那些高得多产品。结果也显示新检索和GDAS产品之间的差别通过考虑RFI修正算法显然被减少。另外,1-DVAR的集中度量标准(2)被发现是为识别陆地检索被射频干扰影响的区域的一个新方法。例如在有强壮得多的射频干扰的那些区域,例如欧洲和日本,<啜class=“a-plus-plus”>1-DVAR的2那么大集中不能被到达,检索结果不能是可靠的或不能被获得。而且,<啜class=“a-plus-plus”>2也与中等或弱的射频干扰为那些区域与改正射频干扰的算法减少。射频干扰的结果检测了由<啜class=“a-plus-plus”>2与那些识别了由几乎一致光谱差别方法。
简介:TheElNino-SouthernOscillation(ENSO)ismodulatedbymanyfactors;mostpreviousstudieshaveemphasizedtherolesofwindstressandheatfluxinthetropicalPacific.Freshwaterflux(FWF)isanotherenvironmentalforcingtotheocean;itseffectandtherelatedoceansalinityvariabilityintheENSOregionhavebeenofincreasedinterestrecently.Currently,accuratequantificationsoftheFWFrolesintheclimateremainchallenging;therelatedobservationsandcoupledocean-atmospheremodelinginvolvelargeelementsofuncertainty.Inthisstudy,weutilizedsatellite-baseddatatorepresentFWF-inducedfeedbackinthetropicalPacificclimatesystem;wethenincorporatedthesedataintoahybridcoupledocean-atmospheremodel(HCM)toquantifyitseffectsonENSO.AnewmechanismwasrevealedbywhichinterannualFWFforcingmodulatesENSOinasignificantway.Asadirectforcing,FWFexertsasignificantinfluenceontheoceanthroughseasurfacesalinity(SSS)andbuoyancyflux(QB)inthewestern-centraltropicalPacific.TheSSSperturbationsdirectlyinducedbyENSO-relatedinterannualFWFvariabilityaffectthestabilityandmixingintheupperocean.Atthesametime,theENSO-inducedFWFhasacompensatingeffectonheatflux,actingtoreduceinterannualQBvariabilityduringENSOcycles.TheseFWF-inducedprocessesintheoceantendtomodulatetheverticalmixingandentrainmentintheupperocean,enhancingcoolingduringLaNinaandenhancingwarmingduringElNino,respectively.TheinterannualFWFforcing-inducedpositivefeedbackactstoenhanceENSOamplitudeandlengthenitstimescalesinthetropicalPacificcoupledclimatesystem.
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简介:Inthispaper,wefirstanalyzedclouddriftwind(CDW)datadistributionintheverticaldirection,andthenreassignedtheheightofeveryCDWintheresearchdomainintermsofbackgroundinformation,andfinally,conductedcontrastnumericalexperimentsofassimilatingtheCDWdatabeforeandafterreassignmenttoexaminetheimpactsontheforecastofthetrackofTyphoonChanthu(1003)from00:00(CoordinatedUniversalTime)21Julyto00:00UTC23July,2010.TheanalysisresultsoftheCDWdataindicatethatthenumberofCDWsismainlydistributedinthemidandupper-troposphereabove500hPa,withthemaximumnumberatabout300hPa.Theheightreassigningmethodmentionedinthisworkmayupdatetheheighteffectively,andtheCDWdataaredistributedreasonablyandnoobviouscontradictionoccursinthehorizontaldirectionafterheightreassignment.Afterassimilatingtheheight-reassignedCDWdata,especiallythewatervaporCDWdata,theinitialwindfieldaroundTyphoonChanthu(1003)becamemorereasonable,andthenthesteeringcurrentleadingthetyphoontomovetothecorrectlocationbecamestronger.Asaresult,thenumericaltrackpredictionsareimproved.