MISR: In-Flight Radiometric Calibration and Characterization Plan

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Reformatting/Annotation SubsystemRadiometric/Geometric SubsystemTop-of-Atmosphere/Cloud SubsystemLevel 1A Level 1B Level 2Raw data ingestRadiance scalingRadiance conditioningReflecting levelparameter generationData reformatting Geometric rectification Cloud classificationand registrationData annotationCloud detectionTOA albedo calculationLevel 4Model generationData analysisResearch publicationResearch/Modeling SubsystemLevel 3High-level parametergenerationGlobal griddingTemporal binningGridding/Binning SubsystemLevel 2Retrieval pathdeterminationAerosol retrievalSurface retrievalAerosol/Surface SubsystemValidationandQualityAssessmentFigure 2.1. MISR Product Generation SystemStandard products generated at the DAAC are critically dependent on calibrationparameters and other lookup data, such as threshold datasets, atmospheric climatologies, aerosoland surface model datasets, which are produced at the SCF. Functions performed at the SCF areseparated from DAAC activities because they require much closer scrutiny and involvement bythe MISR Science Team than the MISR DAAC could provide. Updates to these data structuresoccur infrequently compared to the rate of standard product generation, and therefore fit into themore limited processing capabilities of the SCF. The Level 1A and 1B products are detailedbelow, as they are most pertinent to this document.2.5.1 Level 1A Reformatted Annotated ProductSquare-root encoding is performed in-flight in order to compress MISR data prior totransmission. Thus, the 14-bit data which are produced by each camera are square-root encoded,through use of a table look-up process, and reduced to 12-bit numbers. At the lowest archive levelfor MISR data, Level 1A, this step is reversed, then padded to a 16-bit word. That is, the Level 1Adata are representative of the original camera output. In addition to these camera DN values, theLevel 1A product is appended with platform navigation and MISR engineering parameters, andpoints to the associated radiometric calibration coefficients, as shown in Table 2.1. Metadata filesare generated which assess the data quality by flagging lines of data that are missing, contain oneor more saturated pixels, have extremely high average DN values for the array, have DN valuesfor an active pixel which are less than the offset video, or transition from a scene of highreflectance across most of the array, to a scene of low reflectance across most of the array. Theseconditions may affect the data quality, to some degree, as is discussed in Section 4.2.2. Experiment overview16
Table 2.1. Level 1A productProductLevel 1A: Reformatted AnnotatedProductPrincipal contents• Data numbers linearized via square-root decoding• Navigation and engineering data, and pointer to therelevant ARP file.2.5.2 Level 1B1 Radiometric ProductThe Level 1A data are used as input to the Level 1B1 processing code. The primaryobjective of the MISR Level 1B1 processing algorithm is to produce a measure of incidentradiances, averaged over the in-band response profile, from the camera digital numbers (DN).This parameters are summarized in Table 2.2. The radiometric data are reported at the samespatial resolution as the input DN, and no re-sampling is performed. Processing is done routinelyon all transmitted MISR data.Table 2.2. Level 1B1 Radiometric ProductParameternameUnitsRadiance W m -2 µm -1sr -1HorizontalSampling (Coverage)250 m nadir, 275 m offnadir,or averages per thecamera configuration(Global)Comments• Radiometrically-scaled data• No geometric resampling• 9 cameras, 4 bands• Uncertainty reported in AncillaryRadiometric ProductThe algorithm used to produce the Level 1B1 Radiometric Product requires knowledge ofthe radiometric calibration coefficients for each pixel. This instrument calibration is updatedmonthly using On-Board Calibrator (OBC) data, vicarious calibration (VC) data, histogramequalization (HE) data, and trend data, as available. The coefficients used in the RadiometricProduct generation are documented in the Ancillary Radiometric Product (ARP), summarized inTable 2.4. Also included in the ARP are absolute and relative radiance uncertainties, signal-tonoise(SNR) ratios, spectral parameters, instantaneous fields-of-view (IFOV) information, andvarious threshold parameters used in Level 1A metadata reports which describe the data quality.The ARP is generated at the MISR SCF, updated as needed, and delivered to the DAAC. Thus,production of the ARP is not part of the routine DAAC processing of MISR data, however it fallswithin the purview of this plan.Traditionally, the radiance retrieval is produced using a simple radiance scaling algorithmin which a gain and offset coefficient (specific to each pixel) are used in conjunction with a linearcalibration equation. For MISR, a quasi-linear calibration equation that includes a small quadraticterm is utilized. In addition, point-spread function deconvolution, and in-band response non-In-flight Radiometric Calibration and Characterization Plan, JPL D-1331517
Page 6: 10.4.2 Radiative transfer. . . . .
Page 9 and 10: 1. INTRODUCTION1.1 PURPOSEThis docu
Page 11 and 12: • MISR Algorithm Development Plan
Page 13 and 14: 2.1 MISR SCIENCE OBJECTIVES2. EXPER
Page 15: In addition to these modes, the ins
Page 19 and 20: Table 2.4. Level 1B1 Ancillary Radi
Page 21 and 22: 3. CALIBRATION OVERVIEW3.1 REQUIREM
Page 23 and 24: equally to filter pinholes or scatt
Page 25 and 26: PREFLIGHTDATAIFRCCactivityOtheracti
Page 27 and 28: Multiple methodologies are utilized
Page 29 and 30: laboratory environment. This includ
Page 31 and 32: 4. PREFLIGHT CALIBRATION AND CHARAC
Page 33 and 34: determination was originally planne
Page 35 and 36: Cause: The filters are non uniform
Page 37 and 38: is the affected area is about 30 pi
Page 39 and 40: 5. IN-FLIGHT RADIOMETRIC CALIBRATIO
Page 41 and 42: esponse functions will be verified
Page 43 and 44: the array. Dark current is expected
Page 45 and 46: OBC design effort. The actual uncer
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Page 49 and 50: laboratory measurements. In order t
Page 51 and 52: 6. LEVEL 1B1 RADIOMETRIC PRODUCT AL
Page 53 and 54: flight. Generation of the updated p
Page 55 and 56: 7. CHARACTERIZATIONThe radiance unc
Page 57 and 58: 7.1.4 PolarizationMISR has been des
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Page 61 and 62: 8. CALIBRATION INTEGRITYCalibration
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Page 65 and 66: had all lamps on, and the satellite
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9. MANAGEMENT9.1 PERSONNEL ROLES9.1
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EurOpto (preflight radiometriccal.)
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PRINCIPALINVESTIGATORDavid J. Diner
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• Identifying/specifying all of t
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10. REFERENCES10.1 MISR EXPERIMENT(
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10.3 IN-FLIGHT CALIBRATION METHODOL
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38. Vane, G., T.G. Chrien, J.H. Rei
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APPENDIX A. NOMENCLATUREThe followi
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A.4 CHARACTERIZATIONcalibration. Th
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G 0 , G 1 , and G 2 are the respons
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APPENDIX B. CALIBRATION MODE SEQUEN
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In Cal-Dark data are acquired over
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Config. Home Run is a commanding of
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Repeat for 200 line repeat times, t
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MISR: In-Flight Radiometric Calibration and Characterization Plan

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