c11a-0747. sennel-3 performance improvement for ice sheets · 2017. 3. 6. · guildford, united...
TRANSCRIPT
(1)CentreforPolarObserva3onandModelling,UniversityofLeeds,Leeds,UnitedKingdom([email protected]),(2)isardSATLtd,Guildford,UnitedKingdom,(3)CLS,RamonvilleSaint-Agne,France,(4)LEGOS,Toulouse,France,(5)ESAESRIN,Frasca3,Italy.
SPICEwilldevelopandtestSARprocessingalgorithms,aimingul3matelytoimproveSen3nel-3performanceovericesheets.
InPhase1,SPICEwillgeneratebaselinesolu3ons,usingcurrentlyimplementedprocessingapproaches.
InPhase2,SPICEwillinves3gatenovelalgorithmdevelopmentsaimedatimprovingSARretrievalsoficesheeteleva3on.
• Delay-DopplerProcessing(DDP).SPICEprocessordevelopmentswillinclude:
1. Accoun3ngfortheantennapaUernatthestacklevel,soastoconsidertheangleofeachDopplerbeam.
2. EnablingDopplerbeamfocussingonpar3culartargetsofinterest.
3. CleaningthestackssothattherangebinsofDopplerbeamswithnousefulinforma3onareremoved.
• SAR retracking. In Phase 1, SPICE will inves3gate the performance of exis3ng retrackers. In Phase 2, SPICE willdeveloptwonewSARretrackers,basedonbothanewphysicalandanewempiricalmodel.
• Pseudo-LRM(pLRM)processing.SPICEwilldevelopapLRMprocessingchain,toassessthefeasibilityofgenera3ngalowresolu3onproductfromaclosedburstSARsystem.Ifsuccessful,pLRMcanfacilitatethecrosscomparisonofpulselimitedandSARal3metry,asbothhigherlevelproductscanbegeneratedfromthesameFBRdata.
• AspartoftheSPICEstudy,weareconduc3ngahighlevelevalua3onofalldataproducts,to assess the ability of SAR and pulse limited al3metry to determine reliablemeasurementsofsurfaceeleva3on.
• At each study site, reference datasets comprised of airborne (IceBridge) and satellite(ICESat)measurementswillbeusedtoassesstheSPICEeleva3onproducts.
• Intersec3ons between ground tracks are iden3fied (figure right) and eleva3ondifferencesrela3vetoeachreferencedatasetarecomputed.
• To date, SPICE baseline datasets at Dome C and Vostok have been analysed. Results(figurebelow) indicate comparable levelsofperformancebetweendifferentopera3ngandprocessingmodes.Inpar3cular,theSPICEpLRMsolu3onshowspromisingresultsattheselowreliefstudysites.
• Interferometric and SAR al3metry processing techniques were firstimplemented on an Earth Observing satellite in 2010, when CryoSat-2waslaunched.CryoSat-2SARacquisi3onswere,however,primarilylimitedtoseaiceandwatersurfaces.
• Sen3nel-3, which launched early in 2016, now provides opera3onal SARal3metryoverbothicesheets.TheSPICEstudyaimstoaddresstheneedtoevaluateandop3miseSARprocessingtechniquesfortheseenvironments.
• SPICEwillfocusonfourstudysites:
• TheLakeVostok,DomeCandSpiritsitesinAntarc3ca,wherededicatedSARacquisi3onshavebeenmadebyCryoSat-2.
• TheRussellGlacier inGreenland,whereSAR interferometric (SARIn)FullBitRate(FBR)datawillbeusedtogeneratepseudo-SARmeasurements.
CONTEXT&STUDYSITESSARPROCESSINGIMPROVEMENTOVERICESHEETS
FUTUREWORK
Independentevalua3onofal3metereleva3onsattheDomeCandVostoksites,usingairborne(IceBridge)andsatellite(ICESat2009campaigns)datasets.Ateachsite,SAR,LRMandpLRMeleva3onmeasurementshavebeencomparedto
eachofthereferencedatasets,andthedistribu3onofeleva3ondifferenceshasbeencalculated.
MalcolmMcMillan1*,RogerEscolà2,MònicaRoca2,MariaJoséEscorihuela2,PierreThibaut3,AndrewShepherd1,FrédériqueRemy4,JérômeBenveniste5,AméricoAmbrózio5andMarcoRestano5.
www.seom-spice.org|[email protected]|*CentreforPolarObserva3on&Modelling,UniversityofLeeds,UK
Theloca3onofSPICEstudysitesinAntarc3ca(mainpanel)andGreenland(inset).
• SPICE (Sen3nel-3 Performance improvement for Ice sheets) is a 2 yearstudy funded by ESA’s SEOM (Scien3fic Exploita3on of Opera3onalMissions)program.
• In prepara3on for Sen3nel-3, the project aims to contribute to thedevelopment and evalua3on of novel SyntheSc Aperture Radar (SAR)alSmetryprocessingmethodsovericesheets.
• SPICE will process full bit rate (FBR) CryoSat-2 SAR acquisi3ons usingexis3ngbaselines,generatenovelSARandpseudo-LRM(pLRM)products,and inves3gate the expected performance of Sen3nel-3 prior toopera3onaldataavailability.
SUMMARY
AssessandimproveDelay-Doppleral3meterprocessingforicesheets
EvaluatetheperformanceofSARal3metryrela3vetoconven3onal
pulselimitedal3metry.
AssessanddevelopSARwaveformretrackersforicesheets.
AssesstheimpactonSARal3metermeasurementsofradarwaveinterac3on
withthesnowpack.OBJECTIVES
eleva3
on(m
)
CryoSat-2 LRM CryoSat-2 SAR
SPICE baseline SAR
SPICE pLRM
3000
3100
3200
3250
3150
3050
• SPICEPhase2.
DuringPhase2,wewilldevelopandassesnewalgorithms,aimedat improvingtheDelay-Dopplerandretrackingprocessingchains.SPICE aims to draw on experiences from othermissions (for example Sen3nel-6 development) and related fields of research (forexampleSAMOSAoceanretracking)tocontributetotheimprovementofSARal3metryovericesheets.
• RadarwaveinteracSonwiththesnowpack.
SPICEwillalsoinves3gatetheimpactonSARal3metryofradarwaveinterac3onwiththesnowpack.Firstly,theeffectofbackscaUeringanisotropywillbeassessedbycomparingmeasurementsacquiredfromdifferentviewingdirec3ons.Secondly,acomparisonbetweenCryoSat-2Ku-bandandSARALKa-bandmeasurementswillbeusedtoinves3gateradarwavepenetra3onintothesnowpack.
SPICEPERFORMANCEEVALUATION
Surfaceeleva3on(m)
IceBridgetracks
SPICEtrackscrossingpointsSPICEpLRM
SPICEbaselineSAR
recordnum
ber
recordnum
ber
increasingeleva3on
increasingeleva3on
Topandmiddlepanels.SPICEpLRMandSARwaveformsgeneratedfromthesameSARFBRdata,foratrackcrossingDomeC.BoWompanel.SPICEbaselineSARandpLRMeleva3onsforatrackcrossingDomeC(loca3onshownininsetfigure),comparedtotherangeofCryoSat-2BaselineCLRM
solu3ons.SARandpLRMprofilesarefromdedicatedSARacquisi3onsin2014.TheLRMdataarefromanearcoincidenttrackfromthefollowingorbitcycle.Allsolu3onsresolveabroadlyconsistenttopography,withoffsetsoftheorderof1meterduetothedifferentretrackersused.
Intersec3onsbetweenSPICEandIceBridgereferencedatasetsatDomeC.
C11A-0747.SenSnel-3PerformanceimprovementforIcesheets
CryoSat-2LRM
CryoSat-2SA
R
SPICEbaselineSA
R
SPICEpLRM
CryoSat-2LRM
CryoSat-2SA
R
SPICEbaselineSA
R
SPICEpLRM
CryoSat-2LRM
CryoSat-2SA
R
SPICEbaselineSA
R
SPICEpLRM
CryoSat-2LRM
CryoSat-2SA
R
SPICEbaselineSA
R
SPICEpLRM
22measurements 470measurements80measurements25measurements