Absolute Calibration of Jason-1 and TOPEXPoseidon

Thisarticlewasdownloadedby:[CenterforSpaceScience&AppliedResearch]On:24October2012,At:00:56Publisher:Taylor&FrancisInformaLtdRegisteredinEnglandandWalesRegisteredNumber:1072954Registeredoffice:MortimerHouse,37-41MortimerStreet,LondonW1T3JH,UKMarineGeodesyPublicationdetails,includinginstructionsforauthorsandsubscriptioninformation::Jason-1Calibration/ValidationP.Bonnefonda,P.Exertiera,O.Lauraina,Y.Ménardb,A.Orsonic,G.Jand&E.JeansoudaObservatoiredelaCôted'Azur—CERGA,Grasse,FrancebCentreNationald'EtudesSpatiales,Toulouse,FrancecInstitutGéographiqueNational—CNES,Toulouse,FrancedNOVELTIS,RamonvilleSaintAgne,FranceVersionofrecordfirstpublished:21Jun2010.Tocitethisarticle:P.Bonnefond,P.Exertier,O.Laurain,Y.Ménard,A.Orsoni,G.Jan&E.Jeansou(2003):AbsoluteCalibrationofJason-1andTOPEX/PoseidonAltimetersinCorsicaSpecialIssue:Jason-1Calibration/Validation,MarineGeodesy,26:3-4,261-284Tolinktothisarticle:::30MGDTJ871-10MarineGeodesy,26:261–284,2003CopyrightCTaylor&FrancisInc.ISSN:0149-0419print/1521-060XonlineDOI:10.1080/01490410390251623AbsoluteCalibrationofJason-1andTOPEX/PoseidonAltimetersinCorsicaP.BONNEFONDP.EXERTIERO.LAURAINObservatoiredelaCˆoted’Azur—CERGAGrasse,FranceY.M´ENARDCentreNationald’EtudesSpatialesToulouse,FranceA.ORSONIInstitutG´eographiqueNational—CNESToulouse,FranceG.JANE.JEANSOUNOVELTISRamonvilleSaintAgne,FranceThedoublegeodeticCorsicasite,whichincludesAjaccio-AsprettoandCapeSenetosa(40kmsouthAjaccio)inthewesternMediterraneanarea,hasbeenchosentopermittheabsolutecalibrationofradaraltimeters.Ithasbeendevelopedsince1998atCapeSenetosaand,inadditiontotheuseofclassicaltidegauges,aGPSbuoyisdeployedevery10daysunderthesatellitesgroundtrack(10kmoffshore)since2000.The2002absolutecalibrationcampaignmadefromJanuarytoSeptemberinCorsicarevealedthenecessityofdeployingdifferentgeodetictechniquesonadedicatedsitetoreachanaccuracylevelofafewmm:inparticular,theFrenchTransportableLaserRangingSystem(FTLRS)foraccurateorbitdetermination,andvariousgeodeticequipmentaswellasalocalmarinegeoid,formonitoringthelocalsealevelandmeansealevel.TOPEX/Poseidonaltimetercalibrationhasbeenperformedfromcycle208to365usingM-GDRproducts,whereasJason-1altimetercalibrationusedcyclesfrom1to45usingI-GDRproducts.ForJason-1,improvedestimatesofsea-statebiasandcolumnaratmosphericwetpathdelayaswellasthemostpreciseorbitsavailablehavebeenused.Thegoalofthisarticleistogivesyntheticresultsoftheanalysisofthedifferenterrorsourcesforthetandemphaseandforthewholestudiedperiod,asgeophysicalcorrections,orbitsandreferenceReceived26May2003;accepted13June2003.ThisworkhasbeenconductedandfinancedthankstoCNESandMinistryofResearchfortheFrenchpart.ThankstoC.GailleminwhotakescareofalltheinstrumentsatCapeSenetosaandhaspermittedmakingtheGPSbuoyexperimentasuccess.SpecialthanksalsototheobserversoftheFTLRSfortheirdeepinvestmentduringthe2002Corsicacampaign.AddresscorrespondencetoPascalBonnefond,CERGA,AvenueNicolasCopernic,Grasse,France.E-mail:[e-mail]261Downloadedby[CenterforSpaceScience&AppliedResearch]at00:5624October2012November25,200315:30MGDTJ871-10262P.Bonnefondetal.frame,sealevel,andfinallyaltimeterbiases.Resultsareatthemillimeterlevelwhenconsideringoneyearofcontinuousmonitoring;theyshowagreatconsistencybetweenbothsatelliteswithbiasesof6±3mm(ALT-B)and120±7mm,respectively,forTOPEX/PoseidonandJason-1.Keywordsaltimetercalibration,GPSbuoy,preciseorbit,satellitelaserrangingDuringthelastyears,complementaryaltimetricmissionshavenotablypermittedcompar-inginstruments:relativecalibrationshavebeenachieved,globalstatisticsandresultsshowthepowerofsuchatechnique(DesaiandVincent2003).However,throughthesemis-sions,problemshavebeendiscoveredbothinthealgorithmsandtheinstruments:theSPTRandUSOdriftcorrectionsforERS(Benveniste1997),theoscillatordriftcorrectionsforTOPEX/Poseidon(AVISO1996),andmorerecentlyintheJMRwetpathdelaycorrectionforJason-1.Thishasreinforcedtheinterestofabsolutecalibrationcampaignstodetectsuchproblemsinnear-realtime.Beyondthecalibrationofthealtimeters,thecalibrationsitesalsoareveryusefulinassessingthevariouscomponentsofthealtimetricsystems,evenifitisonlyasingle-pointverific