remote-sensing of water-vapor in the near ir from eos modis

《remote-sensing of water-vapor in the near ir from eos modis》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。

1、IEEETRANSACTIONSONGEOSCIENCEANDREMOTESENSING,VOL.30,NO.5,SEPTEMBER1992U7IRemoteSensingofWaterVaporintheNearIRfromEOS/MODISYoramJ.KaufmanandBo-CaiGaoAbstruct-Remotesensingofthetotalcolumnwatervapordroughtconditionsanddesertificationprocesses.Thesparse(incloudfreeconditions)fromtheproposedMODISi

2、nstrumentlocationofgroundmonitoringstations,especiallyindryareas,ontheNASA’sEarthObservingSystemrequiresspecial“watercallsforanaccurateremotesensingtechniquethatcanprovidevapor”channelsinthenearinfrared(IR).Byusing2near-IR“watervapor”channels(0.905pmand0.940Irm)inadditionwatervaporinformationo

3、nadailybasiswithahighspatialtoexisting“window”channels(0.865pmand1.24pm),itwillresolution(e.g.,1-5kmfromMODIS).bepossibletoderivethetotalcolumnwatervaporamountfromPresentinfraredsounders141,[SI,[22],1291arecapableMODISdata.Aratioofthemeasuredradianceinanabsorbingofretrievingwatervaporprofilesa

4、sabyproductofremotechannelat0.940k0.025pmor0.905+0.015pmtothatinasensingoftheatmospherictemperatureprofiles.Thederivednonabsorbingchannelat0.865+0.020pmisproposedtoretrievethecolumnwatervaporoverland.watervaporprofiledependsinpartontheinitialguessforLOWTRAN-7codewasusedtosimulateremotesensingo

5、fthetemperatureandmoistureprofilesassumedintheinver-watervaporover20differentsurfacecovers.Thesimulationsion[141,beingparticularlysensitivetotheassumedprofileswasusedtooptimizethewatervaporchannelselectionandtoclosetothesurface1271.Asfarasweknow,nosystematictesttheaccuracyoftheremotesensingmet

6、hod.ThechannelselectionminimizestheuncertaintyinthederivedwatervaporcomparisonbetweentotalprecipitablewatervaporderivedbyduetovariationsinthespectraldependenceofthesurfaceinversionoftheHIRSiMSUdataandradiosondemeasure-reflectance.Theselectionalsominimizesthesensitivityofthementshasyetbeenpubli

7、shed.Unpublisheddata(Susskind,selectedchannelstopossibledriftinthechannelposition.Inprivatecommunication)indicatesabsoluteaccuracyof20%.asensitivityanalysisitisshownthattheerrorinthedirectlyRecentlycollectedradiosonde(21cases)andsunphot