CLARREO Pathfinder Inter-calibration: Requirements ...CLARREO Pathfinder, Inter-calibration...
Transcript of CLARREO Pathfinder Inter-calibration: Requirements ...CLARREO Pathfinder, Inter-calibration...
1CLARREO Pathfinder, Inter-calibration Workshop, November, 2016
NASA Langley Research Center
² Inter-calibration of sensors: background
² Mission Requirements & Success Criteria
² On-orbit pointing approach for inter-calibration
² Instrument Field-of-Regard from ISS location
² Other Inter-calibration opportunities
² Inter-calibration event prediction & sampling
² Inter-calibration data products
² Publications
CLARREO Pathfinder Inter-calibration:Requirements, Objectives & Opportunities
Constantine Lukashin, NASA LaRC
Outline:
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NASA Langley Research Center
² LEO and GEO data matching when available (e.g. MODIS and GOES-13).² Uniform and stable surface sites.² Instrument stability by observing the Moon (e.g. SeaWIFS).² Deep Convective Clouds, clear ocean & deserts: involve RT modeling.
Results from C. Roithmayr
Temporal matching: 30 minutes
Inter-Calibration of Sensors in RS: Current
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Inter-calibration of gain:² Type A uncertainty (random) is 5.11% (k=1): due to data matching.² Type B uncertainty (not random) is defined by the MODIS accuracy of 2% (k=1) [pre-launch].² Spectral Type B uncertainty: due to difference in spectral response.
Fundamental limitation of current approach
Results from the GSICS
Inter-Calibration of Sensors in RS: Current
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Threshold Science Requirements:
The CLARREO Pathfinder shall demonstrate the ability to use the reflected solar spectrometer as an in-orbit transfer standard for inter-calibration of the reflectance bands of the VIIRS instrument and the CERES instrument's shortwave channel. The uncertainty contribution from inter-calibration approach should be limited to 0.6% (k=1).
Baseline Science Objectives:
The CLARREO Pathfinder objective is to demonstrate the ability to use the reflected solar spectrometer as an in-orbit transfer standard for inter-calibration of the reflectance bands of the VIIRS instrument and the CERES instrument's shortwave channel. The uncertainty contribution from inter-calibration approach should be limited to 0.3% (k=1).
Inter-Calibration Objectives & Requirements
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Inter-Calibration Concept: CERES & VIIRS
² CLARREO Pathfinder Instrument provides high-accuracy reference on orbit. ² CLARREO Pathfinder Instrument has 2D pointing ability for real-time data matching.² CLARREO Pathfinder data matching with CERES and VIIRS on JPSS:
temporal matching within 10 minutes, on-orbit angular/spacial matching. ² CLARREO Pathfinder location on ISS: ELC-1 Site 3.
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Projection in JPSS cross-track plane
CPF Swath Top view
Red: full CLARREO approachGreen: CLARREO Pathfinder approach
CPF Swath
CPF (ISS, 400 km)
Inter-Calibration of Sensors: CERES & VIIRS
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NASA Langley Research Center
² Gimbal configuration: pitch - roll² Approximate gimbal range of motion at ISS ELC-1 Site 3.² Not all pointing angles are available due to ISS accommodation.² Refine analysis for ISS components affecting RS instrument view in Phase-A.
Accommodation studies by the NASA LaRC Engineering team: J. Leckey, C. Boyer, T. Jackson
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(1) Inter-calibration of Sensors:
² Prediction by orbital modeling² Filter out events with instrument FOV obscured by ISS fixed and rotating structures² Assess the value for every event by modeling² Deliver event parameters to instrument operations team
(2) Calibration of Lunar Spectral Reflectance:
² Prediction of Moon viewing by orbital modeling² Filter out events with instrument FOV obscured by ISS fixed and rotating structures² Assess the value for every lunar geometry by modeling² Coordinate with the instrument calibration team² Deliver event parameters to instrument operations team
(3) Characterization of Surface Sites:
² Prediction by orbital modeling² Filter out events with instrument FOV obscured by ISS fixed and rotating structures² Assess the value for every event by modeling² Deliver event parameters to instrument operations team
² New approach: first inter-calibration by real-time pointing off-nadir !² Inter-calibration on-orbit operations are planned ahead of time !
Inter-Calibration Event Prediction
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² Instrument FOV = 10o
² Time matching +/- 10 minutes² 1262 inter-calibration opportunities over 1 year
Results from C. Roithmayr
Geolocation of the ISS ground track during each opportunity to take measurements for inter-calibrating JPSS cross-track sensors (CERES and VIIRS).
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Inter-Calibration Events: Geolocation
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Inter-calibration with CERES and VIIRS on JPSS
Results from C. Roithmayr
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Behavior of the gimbal: for each opportunity, the maximum and minimum gimbal angle q1, angular speed d(q1)/dt, and angular acceleration d2(q1)/dt2 are shownin the top, middle, and bottom plots, respectively.
Behavior of the gimbal: for each opportunity, the maximum and minimum gimbal angle q2, angular speed d(q2)/dt, and angular acceleration d2(q2)/dt2 are shownin the top, middle, and bottom plots, respectively.
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Inter-Calibration Events: Gimbal Motion
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Simulation ISS ELC-1 Site 3: ² 10 minutes time matching² Instrument field-of-regard² Instrument FOV = 10o
² Instrument FOV obscuration = 0%² Event duration > 30 seconds ² SZA < 75o
² N good events = 1163
VIIRS: 100 samples every 5 seconds(imager re-sampling)
CERES: 3 FOVs every 5 seconds(large FOV)
Margin at 44% for operations not-available on average !
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Inter-Calibration: Sampling & Margin
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CALIBRATION TARGETS:
² Instrumented and not-instrumented Surface Sites (deserts)
² Moon: improve accuracy of lunar spectral reflectance
Other Inter-Calibration Opportunities
SENSORS:
² GEO imagers: NOAA ABI on GOES-16 EUMETSATESA GERB
² Land imagers: USGS Landsat ESA Sentinel-2A/B
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Product Contents Resolution GranuleLevel-1 Products forVIIRSCERESGEO (NOAA, ESA, etc.)Landsat (USGS)Surface SitesMoon
Calibrated and geo-located CPF observations.
Full spectraland spatial resolutionof the CPF RS Instrument.
Each granule contains single CPF inter-calibration event.
Level-4 Products for VIIRSCERES
Collections of CPF (Level-1), VIIRS, and CERES matched data (Level-1 & Level-2).
CLARREO (Level-11) and VIIRS(Level-1 & Level-2, Clouds and Aerosols) data spatially convolved over IC sample. CLARREO Spectral re-sampling.
CLARREO (Level-1) spatially convolved over CERES FOV’s PSF. CLARREO conversion to broadband reflectance. Scene ID from the CERES SSF.
Data processed by the CPF inter-calibration events.
Level-4 Products forVIIRSCERES
Inter-calibration results:Constraints on effective offset, gain, non-linearity, sensitivity to polarization, and spectral degradation.
N/A N/A
Inter-Calibration Data Products
v Additional data analysis – by a separately funded science team
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Roithmayr, C.M., and P.W. Speth, 2012: “Analysis of opportunities for intercalibration betweentwo spacecraft,” Advances in Engineering Research Vol. 1, Chapter 13, Edited: V.M.Petrova, Nova Science Publishers, Hauppauge, NY, pp. 409 - 436.
Lukashin, C., B. A. Wielicki, D. F. Young, K. Thome, Z. Jin, and W. Sun, 2013: “Uncertaintyestimates for imager reference inter-calibration with CLARREO reflected solar spectrometer,” IEEE Trans. on Geo. and Rem. Sensing, special issue on Intercalibration of satellite instruments, 51, n. 3, pp. 1425 – 1436.
Roithmayr, C. M., C. Lukashin, P. W. Speth, G. Kopp, K. Thome, B. A. Wielicki, and D.F. Young, 2014a: “CLARREO Approach for Reference Inter-Calibration of Reflected Solar Sensors: On-Orbit Data Matching and Sampling," IEEE TGRS, v. 52, 10, pp. 6762 - 6774.
Roithmayr, C. M., C. Lukashin, P. W. Speth, D.F. Young, B.A. Wielicki, K. J. Thome, and G.Kopp, 2014b, “Opportunities to Intercalibrate Radiometric Sensors from International Space Station,” J. of Atm. and Oce. Tech., DOI: 10.1175/JTECH-D-13-00163.1.
Wu, A., X. Xiong, Z. Jin, C. Lukashin, B.N. Wenny, J.J. Butler, 2015: “Sensitivity of IntercalibrationUncertainty of the CLARREO Reflected Solar Spectrometer Features,” IEEE TGRS, v. 53, 4741 - 4751, 10.1109/TGRS.2015.2409030
Sun W., C. Lukashin, and D. Goldin, 2015: “Modeling polarized solar radiation for CLARREOinter-calibration applications: Validation with PARASOL data," J. Quant. Spectrosc. Radiat.,v. 150, pp. 121 - 133.
Sun, W., R.R. Baize, C. Lukashin, and Y. Hu, 2015: “Deriving polarization properties ofdesert-reflected solar spectra with PARASOL data,” Atmos. Chem. Phys., 15, 7725 - 7734,doi: 10.5194/acp-15-7725-2015.
CLARREO Inter-Calibration: Key Publications