MODIS Calibration And Characterization For The . - NASA
EOSMODIS Calibration and Characterizationfor the Reflective Solar Bands (RSB)Jack Xiong and Bill Barnes (NASA/GSFC)RSB Group (MODIS Characterization Support Team)Ocean Color Calibration and Characterization Review Meeting, February 11-12, 2004
OutlineEOS Instrument Background Reflective Solar Bands (RSB) Calibration Overview– Pre-launch calibration activities– On-orbit calibration algorithm Calibration Results and Discussions––––––Solar diffuser (SD) bi-directional reflectance factor (BRF)Temperature correction coefficientsResponse versus scan angle (RVS)SD screen (SDS) vignetting function (VF)SD degradation using SD stability monitor (SDSM)m1 trending resultsPage 2
OutlineEOS Challenging Issues and Concerns–––––BRF error’s impact on RSB calibrationInstrument and focal plane temperature effectsOn-orbit RVS characterization limitsPolarization (SBRS/MCST/Miami)SD screen vignetting effect – observations andsimulation results (Xiong/Waluschka)– Scattering (SBRS/Waluschka)– Earth shine (Wolfe)– Calibration (detector’s response) stabilityPage 3
Instrument BackgroundEOS VelocityVector 36 spectral bands withwavelengths from 0.4 to 14.5 µmSpatial resolution at nadir: 250m (2bands), 500m (5 bands) and 1000m4 FPAs: VIS, NIR, SMIR, LWIROn-Board Calibrators: SD/SDSM,SRCA, and BB (plus space view)12 bit (0-4095) dynamic range2-sided paddle wheel scan mirrorscans 2330 km swath in 1.47 sec(1354 data frames, 55º)Day data rate 10.6 Mbps; nightdata rate 3.3 Mbps (100% dutycycle, 50% day and 50% night)Page 4
Instrument BackgroundEOSMODIS Design Parametersand SpecificationsPage 5
Instrument BackgroundOPTICAL SYSTEMEOSVISDBANTRACK12119SCAN34715MODIS Optics SystemVIS FOCAL PLANE14 15151515SWIR/MWIRFOCAL PLANE14 1211SCA9N3475.5 7416715151415152 1SCATRACK19.371SCANLWIRFOCAL PLANE19.371NIR FOCAL PLANESPage 6
Instrument BackgroundEOSMODIS Four Focal Planes (36 bands, 490 detectors)FILTERSVISFILTERS OPTICAL 2211111Instrument FPA Main Frame Temperature9843Silicon9854316986515987414' 149865198742986513' 075210742S106519191810PV HgCdTeSNIR191012106207SiliconT202017302928273334PV HgCdTe353631T132PC HgCdTeCold FPAs: (80. 83, 85k)S: scan direction; T: track directionB13 and B14 have 2 columns of detectors for TDI high and low gain outputsPage 7
Instrument BackgroundEOSOn-board Calibrators (OBCs)Blackbody (BB)Spectro-Radiometric Calibration Assembly (SRCA) Solar Diffuser (SD)Solar Diffuser Stability Monitor (SDSM) BB for thermalemissive bands(TEB) calibrationSD for reflectivesolar bands (RSB)calibrationSDSM formonitoring SDdegradationSRCA for spatialand spectral (RSBonly) monitoringPage 8
Calibration OverviewEOSPre-launch Calibration Calibration and Characterization:– SIS100 (Spectral Integration Sphere) used for RSBradiometric calibration in thermal vacuum (TV) Calibration performed at three instrument temperature plateaus(hot, nominal, and cold) Calibration parameters derived (detector’s response and itstemperature dependence, noise characterization, non-linearity)––––Spectral and spatial characterization (RSR; BBR)Response versus scan angle measurements (RVS)SD BRF measurementsPolarization characterizationPage 9
Calibration OverviewEOSMODIS Calibration Accuracy Requirements (RSB) Band12345678910111213L14L15161718192613H14H0.3Ltyp to 0.9Lmax; within 45º of scan angle range:– Reflectance: 2%; Radiance: 5%– Polarization: 2% (except for B8 at 10001000100010001000Ltyp(W/m 2/sr/ µ)Lmax(W/m 2/sr/ µ)Lcloud(W/m 2/sr/ 6167572501509101087Page 10
Calibration OverviewEOSPre-launch: Thermal Vacuum ChamberOBC BB (AOI 26.7 )Space View Port(AOI 11.2 )Scan MirrorCryogenicSpace ViewSourceBCSSIS 100 45 Port(AOI 60.5 )SpMA0 Nadir Port(AOI 38 )-45 Port(AOI 15.5 )Instrument Temperature Plateaus, SMIR and LWIR FPAs Temperatures (TEB)Page 11
Calibration OverviewEOSPre-launch Pre-launch calibration and characterizationResults– Previous workshops Examples from FM1 Pre-launch Calibration (pages 29-41,56-64)– Science meeting briefings– Decisions for the on-orbit approach Use on-board SD reflectance based calibrationApply a simple linear algorithm (offset 0)Apply pre-launch RVS and temperature coefficientsTrack SD degradation with SDSMDerive and validate SD screen (SDS) vignetting function (VF)on-orbit Use lunar observations to track the response stabilityPage 12
Calibration OverviewEOSOn-orbit Calibration RadiometricSolarDiffuser– Thermal emissive bands (TEB)by BB– Reflective solar bands (RSB)by SD/SDSM Spatial and Spectral– Spatial for RSB and TEB bySRCA– Spectral for RSB by SRCA SRCASDSMLunar Observations (support)BlackbodyScanMirrorSpaceViewMoon– Instrument characterization– RSB response trending– RSB RVSPage 13
Calibration OverviewEOSOn-orbit Calibration SchematicSunSDSM Views:Sun, SD, Dark1.44% ScreenOptional 7.8% Screen(Bands 8-16 saturatew/o screen)SDSMToScan MirrorSDPage 14
EOSCalibration OverviewCalibration AlgorithmSD Reflectance based linear approach:*2 d Earthρ EV cos (θ EV ) dnEV Sun ( EV ) *2ρ SD cos (θ SD ) dnSD d Earth Sun ( SD )*dnEV ( DN EV DN SV ) {1 k INST (TINST ( EV ) TREF )}/ RVS EV*dnSD ( DN SD DN SV ) {1 k INST (TINST ( SD ) TREF )}/ RVS SDρEV·cos(θEV): EV pixel reflectance factor (ρ is the BRF and θ is the solar zenith angle)dn*EV: Detector’s EV “corrected” digital numberdEarth-Sun(EV): Earth-Sun distance at the time of EV observationTINST(EV) : Instrument temperature at EV observationTREF : Instrument reference temperaturekINST : Instrument temperature correction coefficientsDN: Detector’s response (raw DN)Page 15
EOSCalibration OverviewCalibration AlgorithmEV Reflectance factor:SD calibration coefficient:*2ρ EV cos (θ EV ) m1 dnEV d Earth Sun ( EV )ρ SD cos (θ SD )m1 *2dnSD d Earth Sun ( SD )Consider SD degradation ( SD) and SD screen effect (ΓSDS):ρ SD cos (θ SD )m1 * SD Γ SDS2dnSD d Earth Sun ( SD )ρSD: SD pre-launch Bidirectional Reflectance Factor (BRFSD) SD: SD on-orbit degradation (determined by SDSM)ΓSDS: SD screen vignetting function (1 for open mode)Page 16
Calibration OverviewEOSCalibration AlgorithmEV Radiance:LEVESun ρ EV cos (θ EV ) 2π d EarthSun ( EV )Solar Irradiance ESUN:0.4-0.8 µm Thuillier et al., 1998;0.8-1.1 µm Neckel and Labs, 1984;Above 1.1 µm Smith and Gottlieb, 1974Others:Thermal leak applied for SWIR bands (B5-7, B26)Leak coefficients determined from EV night time dataB26 de-striping algorithm added (from C. Moeller of Wisconsin)Page 17
Results and Discussions(SD BRF characterization)EOSm1 ρ SD cos (θ SD )dn d*SD2Earth Sun ( SD ) SD Γ SDSPage 18
Results and Discussions(SD BRF characterization)EOS– Pre-launch characterization performed by Santa Barbara RemoteSensing (SBRS)– A scattering goniometer used in a comparison mode– Traceability maintained from standard reference (characterized atNIST) secondary reference (characterized at SBRS) MODISSD– BRF calibrations performed at 400, 500, 600, 700, 900, and 1700nmover a two-dimensional grid of nine incident directions– 2100nm BRF derived from Total Integrated Scatter (TIS) and BRF atother wavelengths– Quadratic fitting applied to the BRF surfaces at characterizedwavelengths– Interpolation used to obtain BRF for MODIS spectral bandsρ SDBRFλ (θ SD ,φ SD ) a0 a1θ SD a2φ SD a3θSD a4φ SD a5θ SDφ SDPL2θSD : SD Zenith, φSD : SD Azimuth2Page 19
Results and DiscussionsEOS(SD BRF characterization)SBRS PFM BRF at 400nm (J. Young’s memo, PL3095-N06370A):Average of and difference between pre and post BRF scale transferSpatial uniformity and repeatabilityPage 20
Results and Discussions(SD BRF characterization)EOSSD Characterization Uncertainties (J. Young’s memo, ��–NIST reference:0.5%Characterization of SBRC scattering goniometer:0.7%Transfer of NIST BRF scale to MODIS SD:0.5%Solar diffuser characterization:0.5%Solar diffuser spatial non-uniformities:0.7%Interpolation angular / spectrally:0.1%Prelaunch to orbit insertion BRDF change:0.5%Characterization of 8.5% SD screen:0.2%SDSM solar 2% attenuation and SDS impact:0.5%On-orbit stray light elements during the use of the illuminated SDSolar illumination of the SD surrounds0.3%Earthshine through the SD door0.3%Earthshine through nadir aperture door0.1%Errors can be different at different illuminating/viewing anglesRSS 1.6%Page 21
Results and DiscussionsEOS(SD BRF characterization)– On-orbit BRF validation performed using SD observationduring yaw maneuvers at different azimuth angles– Detector’s solar response is proportional to the BRF– Bands 1-4 and 17-19 used to validate the BRF (bands 8-16saturate without SD screen; crosstalk in SWIR bands 5-7 and26)– Results (Terra MODIS) agree with pre-launch values to within 0.25%* (consistency checked among different detectors withina band; * B2 differences vary from -0.21 to 0.41%)– Pre-launch BRF is used in the m1 calculationBand*dnSDBRFSD cos(θSD )1234171819Min Diff Max 0.1747-0.20450.2705-0.13850.2491-0.15900.2552Page 22
Results and DiscussionsEOS(SD BRF characterization)Terra B3 BRF: fitting (solid line); on-orbit data (symbols)Symbols: Yaw numbersPage 23
Results and DiscussionsEOS(SD BRF characterization)Terra B3 BRF: pre-launch (solid line); on-orbit fitting (symbols)Symbols: Yaw numbersPage 24
Results and Discussions(Temperature correction coefficients)EOSm1 ρ SD cos (θ SD )dn d*SD2Earth Sun ( SD ) SD Γ SDS*dnSD ( DN SD DN SV ) {1 k INST (TINST ( SD ) TREF )}/ RVS SDPage 25
Results and DiscussionsEOS(Temperature correction coefficients)Pre-launch characterization resultsMore examples in FM1 (Aqua MODIS) Pre-launch Calibration (pages 29-41)Pre-launch calibration:LSISdnSIS R*Temperature correction coefficients:k INST {R *(TREF ) / R *(TINST ) 1}/(TINST TREF )Page 26
Results and DiscussionsEOS(Response versus scan angles)– Pre-launch characterization and results Examples in FM1 Pre-launch Calibration (pages 56-64)– On-orbit RVS Response trending from SD, SRCA, and Lunar observations These three sectors have different angles of incidence (AOI) to thescan mirror Results used to update pre-launch values (for VIS bands 8, 9, 3, and10) Ocean group applies “additional correction”Page 27
Results and DiscussionsEOS(Response versus scan angles)Page 28
Results and Discussions(Response versus scan angles)EOSRSB Calibration Using the MoonSD Calibrationm1 BRFSD cos(θ SD ) dn*SD2 dEarth Sun ΓSD SDf (view geometry)m1 dn *Moon Moon CalibrationGeometry factors corrected:How:Nighttime orbits, SV port0-20o roll maneuvers, 55o phase angleWhy:No SD degradation, different AOIf f phase angle flibration fover sampling22dSund MoonModis MoonPage 29
Results and Discussions(Response versus scan angles)EOSGeometry factors corrected:f Librationf phase angle flibration fover sampling22ddSun MoonModis MoonOver-samplingPhase anglePage 30
Results and DiscussionsEOS(Response versus scan angles)SD AOI 50.2 Moon AOI 11.2 Symbols are the band numbers; B-side response normalized to the A-sideOptics (scan mirror) degradation at different AOITime-dependent RVS implemented in MODIS L1B code using response trendingresults from SD, SRCA (AOI 38º), and the MoonPage 31
Results and Discussions(SDS vignetting function)EOSm1 ρ SD cos (θ SD )dn d*SD2Earth Sun ( SD ) SD Γ SDSPage 32
Results and Discussions(SDS vignetting function)EOS– No pre-launch characterization activities– On-orbit characterization using ratio of detector’s solar responsewith SDS to that without SDS; on-orbit yaw maneuver data sets– VF determined from bands 3-4 and 17-19 and applied to bands 816 which saturate without SDS– Fitting results agree with observations to within about 0.30%– Results of quadratic fitting coefficients used in m1 calculationΓ SDS** dnSD dnSD coscosθθ()()SD SDS DownSD SDS Up Page 33
Results and DiscussionsEOS(SDS vignetting function)BandMin DiffMax (difference in %)Page 34
Results and Discussions(SD degradation using SDSM)EOSm1 ρ SD cos (θ SD )dn d*SD2Earth Sun ( SD ) SD Γ SDSPage 35
Results and Discussions(SD degradation using SDSM)EOSSD (BRF) degradation from SDSM SD dcSD viewdcSun viewLarge ripples seen from SDSM Sun view responseRipples caused due to design error in a SDSM componentThis approach did not workRelative approach developedSDSM detectorsCenter wavelength 62D7856.49D8904.29D9936.23dcSun view: SDSM detector’s Sun view digital count (DC) with dark signal subtracteddcSD view: SDSM detector’s SD view digital count (DC) with dark signal subtractedand SD BRF factor correctedPage 36
Results and DiscussionsEOS(SD degradation using SDSM) SD dcSD viewdcSun viewOriginal approachnot working!!Large ripples seen inSDSM Sun view responseSDSM data during SD calibrationPage 37
Results and Discussions(SD degradation using SDSM)EOS(Leland and Arecchi, 1995, SPIE, 2475, 384)SDSM data from YawTerra MODIS SDSM D9 degradation trendingNormalize to SDSM D9 at 936nmdc SD SDdc SunD1 dc D1 SD view / dcSun view D9D9dc/dc SD viewSun view Page 38
Results and DiscussionsEOS(SD degradation using SDSM)SDSM D1 TrendingGreen: no-normalization to D9Red: normalize to D9 at 936nmSDSM D2 TrendingPage 39
Results and DiscussionsEOS(SD degradation using SDSM)Time: day from year 2000Page 40
Results and DiscussionsEOS(m1 trending results)Examples given for B8 and B11. All m1 trending results are available.Page 41
Results and DiscussionsEOS(m1 trending results)Examples given for B8 and B11. All m1 trending results are available.Page 42
Results and Discussions(Summary)EOS MODIS RSB calibration error budget included– SD characterization errors (NIST reference, standardtransfer, instrument effect, measurements errors– Pre-launch to on-orbit BRF change estimate– SD and SDSM screen impact– Stray light elements (e.g. Earthshine related) Considering all the factors identified in the calibrationchain, the calibration is within the instrumentspecifications– Reflectance: 2%; Radiance: 5% Caveats– Polarization correction, if necessary, is used in the scienceapplication algorithm, not in the L1B calibration– RVS changes on-orbit, if not fully characterized, will causeadditional errors (at different AOIs from that of the SD)Page 43
List of Acronyms and gle of IncidenceBlackbodyBand to Band RegistrationBlackbody Calibration SourceBi-directional Reflectance Distribution FunctionBi-directional Reflectance FactorEarth ViewFocal Plane AssemblyInstantaneous Field Of ViewNadir Aperture DoorOn Board CalibrationOut-of-BandReflective Solar BandsRelative Spectral ResponseResponse Versus Scan AngleThermal Emissive BandsSolar DiffuserSolar Diffuser ScreenSolar Diffuser Stability MonitorSignal to Noise RatioSpherical Integrating SourceSpectral Measurement AssemblySpectro-Radiometric Calibration AssemblySpace View DoorSpace View SourceTime Delayed IntegrationTop of AtmosphereVignetting FunctionPage 44
MODIS Calibration and Characterization for the Reflective Solar Bands (RSB) Jack Xiong and Bill Barnes (NASA/GSFC) RSB Group (MODIS Characterization Support Team) Ocean Color Calibration and Characterization Review Meeting, February 11-12, 2004. Outline EOS Instrument Background
correction for MODIS Terra (Meister et al., 2012), residual de-trending and MODIS Terra-to-Aqua cross-calibration (Lyapustin et.al, 2014). The L1B data are first gridded into 1km MODIS sinusoidal grid using area-weighted method (Wolfe et al., 1998). Due to cross-calibration, MAIAC processes MODIS Terra and Aqua jointly as a single sensor. 2.
Aerosol Optical Depth at 0.55 micron MODIS-Terra/Aqua 00.02/02.07 OPS TS Atmospheric Water Vapor (QA-weighted) MODIS-Terra/Aqua 00.02/02.07 OPS TS MODIS-Terra/Aqua 00.02/02.07 OPS TS Cloud Fraction (Day and Night) MODIS-Terra/Aqua 00.02/02.07 OPS TS Cloud Fraction (Day only/Night only)) MODIS-Terra/Aqua 00.02/02.07 OPS TS
MOD43B3C: MODIS/Terra Albedo 16-Day L3 Global 5km ISIN Grid MOD43B4C: MODIS/Terra Nadir BRDF-Adjusted Reflectance 16-Day L3 Global 5km ISIN Grid Products at _ degree MOD43C1: MODIS/Terra Albedo 16-Day L3 Global 0.25Deg CMG MOD43C2: MODIS/Terra BRDF/Albedo Parameters 16-Day L3 Global 0.25Deg CMG
MODIS/Terra Surface Reflectance Daily L2G Global 250m SIN Grid MOD09GQ 6 1,028 . Suomi NPP NOAA-20 JPSS-2 JPSS-3 l fly JPSS-4-art JPSS Program Office Decadal Survey Program of Record . MODIS VIIRS VIIRS instrument adopted many of the qualities of MODIS IPO benefited from MODIS experience - But not all science needs were accommodated
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The MODIS development was managed by NASA’s Goddard Space Flight Center (GSFC) in Greenbelt, Maryland. The MODIS instruments were designed, built, and tested by Raytheon / Santa Barbara Remote Sensing (SBRS) in Goleta, California. The MODIS Characterization
Calibration (from VIM3) Continued NOTE 1 A calibration may be expressed by a statement, calibration function, calibration diagram, calibration curve, or calibration table. In some cases, it may consist of an additive or multiplicative correction of the indication with associated measurement uncertainty. NOTE 2 Calibration should not be .
Accounting Standard (IAS) terminology and requiring pre sentation in International Standard format. Approach – These qualifications were designed using Pearson’s Efficacy Framework. They were developed in line with World-Class Design principles giving students who successfully complete the qualifications the opportunity to acquire a good knowledge and understanding of the principles .
