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GRACE时变重力场的高斯平滑研究.docx

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GRACE时变重力场的高斯平滑研究 Introduction: GRACE(GravityRecoveryandClimateExperiment)isajointprogramoftheNationalAeronauticsandSpaceAdministration(NASA)andtheGermanAerospaceCentre(DLR)tostudytheEarth’sgravityfieldanditstemporalvariations.Themissionwaslaunchedin2002withtwoidenticalsatellitesorbitingintandemformationwithonboardprecisioninstrumentstomeasurethedistancebetweenthem. Thetime-variablegravityfieldmeasuredbytheGRACEsatellitesprovidesvaluableinsightsintotheEarth’shydrological,oceanographic,andgeophysicalprocesses.Thedatacollectedhasrevolutionizedourunderstandingofglobalgroundwaterstorage,icesheetandglaciermassvariations,andoceancurrentdynamics. OneofthemostessentialstepsinprocessingtheGRACEdataistouseaGaussiansmoothingfiltertoreducethenoiseandtoextractmeaningfulsignalsfromthedata.ThispaperaimstoexploretheuseoftheGaussiansmoothingfilterforprocessingtheGRACEdatatogeneratesmoothandaccuratetime-variablegravityfieldsolutions. Methodology: TheGaussiansmoothingfilterisamathematicaltoolusedtoremovethehigh-frequencyvariationsintheGRACEdataandretainthelow-frequencyvariationorsignal.ThefilterworksbyweightingeachdatapointintheinputsignalwithaGaussiandistributioncenteredatthatpoint. SeveralstudieshaveusedtheGaussiansmoothingfiltertoanalyzethetemporalvariationsintheEarth’sgravityfield,includinggroundwaterdepletion,icemasschanges,andsealevelrise.ThefilterhasbeenshowntoprovideaccurateandrobustresultsandhasbecomeastandardtoolforprocessingGRACEdata. ToapplytheGaussiansmoothingfiltertoGRACEdata,thedataisfirstprocessedtoremoveanyerrorsornoise.Thiscanbedoneusingmethodssuchasoutlierrejection,atmosphericcorrection,andremovalofexternalnoisesources.ThefiltereddataisthensmoothedusingtheGaussianfilter,whichremoveshigh-frequencynoiseandretainslow-frequencyvariation. Results: SeveralstudieshavedemonstratedtheeffectivenessoftheGaussiansmoothingfilterinimprovingtheaccuracyandreliabilityofGRACEdataanalysis.Forexample,Chenetal.(2015)usedtheGaussianfiltertoextractthetemporalvariationsintheCaliforniaCentr