nasa snpp cross track infrared sounder (cris) level 1b ... · quality = 2 (invalid) spectral...

NASASNPPCrossTrack InfraredSounder(CrIS) Level 1BQuality Flags DescriptionDocumentUniversityofWisconsin-MadisonSpaceScienceandEngineeringCenter

Version1.0

May2017

JoeTaylor

UW-MadisonSSEC

2

RevisionHistory

DocumentVersion Date CommentDraft 2016-02-18 Creationofdocument0.1(Beta3) 2016-03-24 ConsistentwithBeta3implementation1.0(Version1.0RC) 2016-07-10 UpdatedforproposedV1.0implementation1.1(Version1.0RC) 2016-07-22 Added threshold value tables and updated

dependencytrees1.2(Version1.0RC) 2016-07-25 Addedthresholdvalues1.3(Version1.0RC) 2016-07-29 Added preliminary threshold values for

“Invalid Instrument Temperature” and“ExcessThermalDrift”

1.4(Version1.0RC) 2016-08-01 Removed redundant check of ICT and DSwindow sizes from L1b Quality Invalid;removed ES Mag Spectrum Check; removedMet Laser Quality QF; added ISA DegradedQF.

1.5(Version1.0RC1) 2016-08-12 Added information on band specific inputsandoutputs (colorcodeddependency trees);fixed error in rad cal quality flag = 1(degraded)dependencytree;addedl1afilltorad cal quality flag = 2 (invalid) dependencytree.

1.6(Version1.0RC3) 2016-08-24 Upped Excess Thermal Drift Threshold to1.0K

1.7(Version1.0RC6) 2016-10-15 Removed section with detail ofRDR/SDR/GEO IDPS QFs; added caveat onknown error in false positives for rad_qualandqualflags.

1.8(Version1.0RC7) 2016-11-07 Updated lunar intrusion info and rollingwindow threshold information. Added CrISL1Breferencedocuments.

1.9(Version1.0RC8) 2017-02-08 No significant changes from RC7; documentreviewedforrelease.

1.10(Version1.0) 2017-05-01 Additionofintroduction.Noothersignificantchanges from RC8; document reviewed forrelease.

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TableofContents1 Introduction..................................................................................................................................................................6

1.1 Overview................................................................................................................................................................6

1.2 References.............................................................................................................................................................6

2 L1BFlagDescriptions...............................................................................................................................................7

2.1 L1BQuality...........................................................................................................................................................8

2.2 GeoQuality...........................................................................................................................................................9

2.3 RadiometricCalibrationQuality...............................................................................................................11

2.3.1 ICTTemperatureStability..................................................................................................................13

2.3.2 ICTTemperatureConsistency..........................................................................................................13

2.3.3 NumberofValidPRTTemperatures.............................................................................................13

2.3.4 ESImpulseNoiseCount.......................................................................................................................14

2.4 SpectralCalibrationQuality.......................................................................................................................14

2.5 ImaginaryRadianceAnomaly...................................................................................................................16

2.6 LunarIntrusionDetected............................................................................................................................16

2.7 InvalidInstrumentTemperature.............................................................................................................16

2.8 ExcessThermalDrift.....................................................................................................................................17

2.9 FCEDetected.....................................................................................................................................................17

2.10 FCECorrectionFailed.................................................................................................................................17

2.11 NeonCalibrationQuality..........................................................................................................................18

2.12 ISADegraded..................................................................................................................................................18

2.13 L1aESMissing...............................................................................................................................................18

2.14 BitTrimMismatch.......................................................................................................................................18

2.15 ScanLineMissing8SecSci......................................................................................................................19

3 L1BtoSDRqualityflagcomparison................................................................................................................20

4 GeolocationFlagDescriptions...........................................................................................................................22

5 CaveatsandKnownIssues..................................................................................................................................23

4

FiguresFigure1:L1bQualityFlagdependencytreeforL1bQuality=1(Degraded).........................................8

Figure2:L1bQualityFlagdependencytreeforL1bQuality=2(Invalid)..............................................9

Figure3:Geoqualitydependencytree.................................................................................................................10

Figure 4: Radiometric Calibration Quality Flag dependency tree for Rad Cal Quality = 1(Degraded). ThisflagconditionisimplementedwithreducedfunctionalityinVersion1.0........................................................................................................................................................................................12

Figure5:RadiometricCalibrationQualityFlagdependencytreeforRadCalQuality=2(Invalid)........................................................................................................................................................................................12

Figure 6: Spectral Calibration Quality Flag dependency tree for Spectral Cal Quality = 1(Degraded). ThisflagconditionisimplementedwithreducedfunctionalityinVersion1.0........................................................................................................................................................................................15

Figure7:SpectralCalibrationQualityFlagdependencytreeforSpectralCalQuality=2(Invalid).ThisflagconditionisimplementedwithreducedfunctionalityinVersion1.0.........................15

5

TablesTable1:l1b_qualbitassignments..............................................................................................................................7

Table2:InputstoL1bQualitydependencytree.................................................................................................8

Table3:L1bQualityvaluesanddescription.........................................................................................................8

Table4:AbsoluteESSpectrumthresholdvaluesandwavenumberranges...........................................9

Table5:GeoQualityinputs........................................................................................................................................10

Table6:GeoQualityvaluesanddescription......................................................................................................10

Table7:InputstoRadiometricCalibrationQualitydependencytree.....................................................11

Table8:RadiometricCalibrationQualityvaluesanddescription............................................................11

Table9:InputstoSpectralCalibrationQualitydependencytree.............................................................14

Table10:SpectralCalibrationQualityvaluesanddescription..................................................................14

Table11:ImaginaryRadianceAnomalyvaluesanddescription..............................................................16

Table12:ImaginaryRadianceAnomalythresholdvaluesandwavenumberranges......................16

Table13:LunarIntrusionDetectedQualityFlagvaluesanddescription.............................................16

Table14:InvalidInstrumentTemperatureQualityFlagvaluesanddescription..............................16

Table15:Validrangesforinstrumenttemperatures.....................................................................................17

Table16:ExcessThermalDriftQualityFlagvaluesanddescription......................................................17

Table17:ExcessThermalDriftThreshold..........................................................................................................17

Table18:FCEDetectedQualityFlagvaluesanddescription......................................................................17

Table19:FCECorrectionFailedQualityFlagvaluesanddescription....................................................18

Table20:NeonCalibrationQualityFlagvaluesanddescription..............................................................18

Table21:ISADegradedQualityFlagvaluesanddescription.....................................................................18

Table22:L1aESMissingQualityFlagvaluesanddescription...................................................................18

Table23:BitTrimMismatchQualityFlagvaluesanddescription...........................................................19

Table24:ScanLineMissing8SecSciQualityFlagvaluesanddescription..........................................19

Table25:L1BtoSDRqualityflagcomparison,sortedbySDRQualityFlag.........................................20

Table26:L1BtoSDRqualityflagcomparison,sortedbyL1BQualityFlag.........................................21

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1 Introduction

1.1 OverviewThisdocumentprovidesdetailedinformationregardingtheLevel1BQualityFlag(QF)variableinVersion 1.0 of theNASACross-track Infrared Sounder (CrIS) Level 1B (L1B) data product,includingthederivationandmeaningoftheindividualflagsthatmakeuptheQFvariable.ThisdocumentisintendedtosupplementthemoregeneralinformationintheNASASNPPCrossTrackInfraredSounder(CrIS)Level1BProductUsers’Guide,Version1.0.ForguidanceonusingQFs,aswellasotherinformationregardingtheCrISL1Bdataproduct,refertothatdocument.

1.2 References1. NASASNPPCrossTrackInfraredSounder(CrIS)Level1BProductUsers’Guide,Version1.02. NASASNPPCrossTrackInfraredSounder(CrIS)Level1BDeltaAlgorithmTheoreticalBasis

Document(ATBD),Version1.03. InstallationInstructionsfortheCrISL1BVersion1.0Rc8SoftwarePackage.4. CrossTrack Infrared Sounder (CrIS) SensorDataRecord (SDR)User’s Guide, Version 1.0,

NOAATechnicalReportNESDIS1435. JointPolarSatelliteSystem(JPSS)OperationalAlgorithmDescription(OAD)Document for

Cross-track InfraredSounder (CrIS) SensorDataRecord (SDR) Software,RevisionE, JointPolarSatelliteSystem(JPSS)GroundProjectCode474474-00071

6. JointPolarSatelliteSystem(JPSS)AlgorithmSpecificationVolumeI:SoftwareRequirementSpecification (SRS) for the CrIS RDR/SDR, Revision D, Joint Polar Satellite System (JPSS)GroundProjectCode474474-00448-01-03

7. JointPolarSatelliteSystem(JPSS)AlgorithmSpecificationVolumeII:DataDictionaryfortheCrISRDR/SDR,RevisionE,JointPolarSatelliteSystem(JPSS)GroundProjectCode474474-00448-02-03-B0200

8. JointPolarSatelliteSystem(JPSS)CrossTrackInfraredSounder(CrIS)SensorDataRecords(SDR)AlgorithmTheoreticalBasisDocument(ATBD),RevisionC,JointPolarSatelliteSystem(JPSS)GroundProjectCode474474-00

7

2 L1BFlagDescriptions

Table1:l1b_qualbitassignments.

Name BitAssignment InitialReleaseLWL1BQuality B0–B1 Beta3MWL1BQuality B2–B3 Beta3SWL1BQuality B4–B5 Beta3GeoQuality B6 Version1LWRadiometricCalibrationQuality B7–B8 Version1MWRadiometricCalibrationQuality B9–B10 Version1SWRadiometricCalibrationQuality B11–B12 Version1LWSpectralCalibrationQuality B13–B14 Version1MWSpectralCalibrationQuality B15–B16 Version1SWSpectralCalibrationQuality B17–B18 Version1LWImaginaryRadianceAnomaly B19 Beta3MWImaginaryRadianceAnomaly B20 Beta3SWImaginaryRadianceAnomaly B21 Beta3LWLunarIntrusionDetected B22 Version1MWLunarIntrusionDetected B23 Version1SWLunarIntrusionDetected B24 Version1InvalidInstrumentTemperature B25 Version1ExcessThermalDrift B26 Version1FCEDetected B27 FCECorrectionFailed B28 NeonCalibrationQuality B29 Version1ISADegraded B30 Version1Unassigned B31–B47 LWL1aESMissing* B48 Beta3MWL1aESMissing* B49 Beta3SWL1aESMissing* B50 Beta3BitTrimMismatch* B51 Beta3ScanLineMissing8SecSci* B52 Beta3Unassigned B53–B64 *replicatedfromES/l1a_qual

8

2.1 L1BQualityThese are summary flags (LW,MW, SW)with value range 0 – 3. The dependency trees areshowninFigure1(L1BQuality=1)andFigure2(L1BQuality=2),withtheinputssummarizedinTable2.L1bQualityFlagValuesaresummarizedinTable3andl1b_qualbitassignmentsaredefinedinTable1.

Table2:InputstoL1bQualitydependencytree.

Input InputType Reference Version1RadiometricCalibrationQuality QualityFlag Section2.3 YesSpectralCalibrationQuality QualityFlag Section2.4 YesGeoQuality QualityFlag Section2.2 YesBitTrimMismatch QualityFlag L1aQF YesScanLineMissing8SecSci QualityFlag L1aQF YesL1aESMissing QualityFlag L1aQF YesImaginaryRadianceAnomaly QualityFlag Section2.5 YesESSpectrum Value(testvs.threshold) Table4 NO(TBR)

Table3:L1bQualityvaluesanddescription

Value Description0 NoL1Bqualityissues1 L1Bquality‘Degraded’.RefertoL1a,geo,L1bqualityflagsformoreinformation2 L1Bquality‘Invalid’.RefertoL1a,geo,L1bqualityflagsformoreinformation

Figure1:L1bQualityFlagdependencytreeforL1bQuality=1(Degraded).

OR

Radiometric Calibration Quality = 1 (Degraded)

Spectral Calibration Quality = 1 (Degraded)

Geo Quality = 1 (Invalid)OR

L1b Quality = 1 (Degraded)

Black Text / Lines: Version 1 proposed implementationGrey Text / Lines: Possible future implementation

Grey Fill: Band Dependent (LW, MW, SW)

9

Figure2:L1bQualityFlagdependencytreeforL1bQuality=2(Invalid).

Table4:AbsoluteESSpectrumthresholdvaluesandwavenumberranges

Band WavenumberRangeforthresholdcheck ThresholdValueMin(Index) Max(Index)

LW 242(TBR) 530(TBR) MW 234(TBR) 394(TBR) SW 40(TBR) 80(TBR)

2.2 GeoQualityThis is a summary flagof theoverall geolocationqualitywithvalue range0–1. l1b_qualbitassignmentisdefinedinTable1.

OR

Radiometric Calibration Quality = 2 (Invalid)


Bit Trim = 1 (Failed)

OR

L1b Quality = 2 (Invalid)

Scan Line Missing 8 Sec Sci = 1

OR

ES Data Missing = 1

OR

Imaginary RadianceAnomaly = 1

OR

⎮ES Spectrum⎮ > ThresholdBlack Text / Lines: Version 1 proposed implementation

Grey Text / Lines: Possible future implementationGrey Fill: Band Dependent (LW, MW, SW)

L1a Fill = 1

OR

OR

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Table5:GeoQualityinputs

Input InputType Reference Version1obs-time-missing QualityFlag GeoQF Yesservo-errors-missing QualityFlag GeoQF Yesspacecraft-diary-missing QualityFlag GeoQF Yesstale-utcpole QualityFlag GeoQF Yes

Table6:GeoQualityvaluesanddescription

Value Description0 Nogeolocationqualityissues1 Geolocationqualityissues.Refertogeo_qualformoreinformation.

Figure3:Geoqualitydependencytree.

OR

geo_qual:obs-time-missing = 1

geo_qual:servo-errors-missing = 1

Geo Quality = 1

geo_qual:spacecraft-diary-missing = 1


geo_qual:stale-utcpole = 1

OR

OR

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2.3 RadiometricCalibrationQualityThesearesummaryflagsdescribingtheoverallradiometriccalibrationquality(LW,MW,SW)withvaluerange0–2. ThedependencytreesareshowninFigure4(RadiometricCalibrationQuality=1)andFigure5(RadiometricCalibrationQuality=2),withtheinputssummarizedinTable 7. Radiometric Calibration Quality Flag values are summarized in Table 8, and thel1b_qual bit assignments are defined in Table 1. These flags are implemented at reducedfunctionalityfortheVersion1.0release.

Table7:InputstoRadiometricCalibrationQualitydependencytree

Input InputType Reference Version1DSWindowSize Value(testvs.threshold)

Threshold=26ifmovingwindowsize=31

Figure4Figure5

Yes

ICTWindowSize Value(testvs.threshold)Threshold=26ifmovingwindowsize=31

Figure4Figure5

Yes

ICTTemperatureStability Value(testvs.threshold) Section2.3.1 YesICTTemperatureConsistency Value(testvs.threshold) Section2.3.2 YesNumberofValidPRTTemperatures Value(testvs.threshold) Section2.3.3 Yes(TBR)ESImpulseNoiseCount Value(testvs.threshold) No(TBR)ExcessThermalDrift QualityFlag Section2.8 YesInvalidInstrumentTemperature QualityFlag Section2.7 Yes

Table8:RadiometricCalibrationQualityvaluesanddescription

Value Description0 Goodradiometriccalibration1 Degradedradiometriccalibration2 Invalidradiometriccalibration

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Figure4:RadiometricCalibrationQualityFlagdependencytreeforRadCalQuality=1(Degraded).ThisflagconditionisimplementedwithreducedfunctionalityinVersion1.0.

Figure5:RadiometricCalibrationQualityFlagdependencytreeforRadCalQuality=2(Invalid).

OR

0 < DS Window Size <Threshold Window Size (26)

0 < ICT Window Size <Threshold Window Size (26)

ICT Temperature Stability > Threshold

OR

Radiometric Calibration Quality = 1 (Degraded)

ICT Temperature Consistency > Threshold

0 < Number of Valid PRT Temperatures < Threshold

OR

ES Impulse Noise Count > Threshold

OR

Excess Thermal Drift = 1

OR

OR

Invalid Instrument Temperature = 1

OR



OR

DS Window Size = 0

ICT Window Size = 0

Radiometric Calibration Quality = 2 (Invalid)



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2.3.1 ICTTemperatureStability

ThresholdValue: 1.0(TBR)ictTempStabilityThreshold

FromtheSDRUser’sGuide[REF1]:

ICT_TemperatureStabilitymeasuresthestabilityofthetwoPRTmeasurementsoftheICT.Thisvariableiscalculatedusingthefollowingequation:

ICTTS = T i( )− 1ICTWS

T j( )j=1

ICTWS

∑⎡

⎣⎢

⎤

⎦⎥

i=1

ICTWS

∑2

ICTWS −1( ) (1.1)

where ICTWS is the ICTWindow Size,T i( ) = 1N

T i,k( )k=1

N

∑ ,where T(i,k) is the converted

PRT temperature in the validated kth epoch, represents the average ICT temperaturemeasuredfromaPRTfortheithscan.ThisvariableissetseparatelyforthetwoPRTs.

2.3.2 ICTTemperatureConsistency

ThresholdValue: 1.0(TBR)ictTempConsistencyThreshold


ICT_TemperatureConsistency measures the consistency between the two PRTmeasurementsoftheICT.Thisvariableiscalculatedusingthefollowingequation:

ICTTC = 1ICTWS

T1 i( )i=1

ICTWS

∑ − 1ICTWS

T2 i( )i=1

ICTWS

∑ (1.2)

The nomenclature is similar to the ICT_TemperatureStability variable except that thesubscripts1and2denotethetwoPRTs,respectively.

2.3.3 NumberofValidPRTTemperaturesThethresholdvaluefromtheIDPS/ADLconfiguration(PCT)binaryfileisnotedbelow.

ThresholdValue: 15(numOfValidPRTTempThreshold)


numberOfValidPRTTemperatures represents the number of PRT temperatures that havebeenvalidatedusingtheproceduredescribedbelow.Themeanandstandarddeviationofthe PRT temperatures is calculated to identify any outliers, which are defined as beingdifferent from themean by an amount ofmore than 3-sigma (standard deviation). Theoutliersdonotentersubsequentprocessing.

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2.3.4 ESImpulseNoiseCountThethresholdvaluefromtheIDPS/ADLconfiguration(PCT)binaryfileisnotedbelow.

ThresholdValue: 2(impulseNoiseCountThreshold)

2.4 SpectralCalibrationQualityThesearesummaryflags(LW,MW,SW)describingtheoverallspectralcalibrationqualitywithvalue range 0 – 2 where the dependency trees are shown in Figure 6 (Spectral CalibrationQuality = 1) and Figure 7 (Spectral Calibration Quality = 2), with the inputs summarized inTable9.QualityFlagvaluesaresummarizedinTable10,andthel1b_qualbitassignmentsaredefinedinTable1. TheseflagsareimplementedatareducedfunctionalityfortheVersion1.0release.

Theusageof “MetLaserMonitored” for v1.0 remainsToBeReviewed (TBR). If it is omittedfromv1.0, thedependencytrees for“Degraded”and“Invalid”SpectralCalibrationQualitywillneedtobemodifiedaccordingly.

Table9:InputstoSpectralCalibrationQualitydependencytree

Input InputType Reference Version1FCEDetected QualityFlag Section2.9 NoNeonCalibrationQuality QualityFlag Section2.11 YesISADegraded QualityFlag Section2.12 YesMetLaserMonitored TBD NO

Table10:SpectralCalibrationQualityvaluesanddescription

Value Description0 Goodspectralcalibration1 Degradedspectralcalibration2 Invalidspectralcalibration

15

Figure6:SpectralCalibrationQualityFlagdependencytreeforSpectralCalQuality=1(Degraded).ThisflagconditionisimplementedwithreducedfunctionalityinVersion1.0.

Figure7: SpectralCalibrationQualityFlagdependencytreeforSpectralCalQuality=2(Invalid). ThisflagconditionisimplementedwithreducedfunctionalityinVersion1.0.

OR

FCE Detected = 1

Neon Calibration Quality = 1


ISA Degraded = 0

AND


ISA Degraded = 1

AND

OR



OR

FCE Correction Failed = 1


Spectral Calibration Quality = 2 (Invalid)

ISA Degraded = 1

AND



16

2.5 ImaginaryRadianceAnomalyLargeimaginarycomponentofthecalibratedradianceisanindicationofpoorqualityofthethecalibratedradiance. Theseflags(LW,MW,SW)indicatewhetherthe imaginarycomponentofthe calibrated radiance exceeds the defined thresholds,with value range 0 – 1. L1b_qual bitassignmentsaredefinedinTable1.

Table11:ImaginaryRadianceAnomalyvaluesanddescription

Value Description0 Imaginarycomponentofthecalibratedradianceiswithinthethresholdvalue1 Imaginarycomponentofthecalibratedradianceexceedsthethresholdvalue

Table12:ImaginaryRadianceAnomalythresholdvaluesandwavenumberranges

Band WavenumberRangeforthresholdcheck ThresholdValueMin(Index) Max(Index)

LW 242 530 +/-1.5MW 234 394 +/-0.88SW 40 80 +/-0.05

2.6 LunarIntrusionDetectedThe Lunar Intrusion Detected flags indicate that a lunar intrusion has been detected in asignificantnumberofthedeepspacereferencespectrawithinthemovingaveragewindowspan.If lunar intrusion is detected, the DS spectrum is marked as invalid and excluded from themovingwindowaverage.ThisresultsinareducednumberofDSspectraintheslidingwindowaverageusedinthecalibrationofthecurrentobservation.Theseflagshavearangeof0–1,andthel1b_qualbitassignmentisdefinedinTable1.

Table13:LunarIntrusionDetectedQualityFlagvaluesanddescription

Value Description0 NoDSviewsaffectedbylunarintrusion1 AtleastoneDSviewisaffectedbymoonwithinthemovingwindow

2.7 InvalidInstrumentTemperatureThe Invalid Instrument Temperature flag is intended to identify the situation when themeasured temperaturesof certain instrument componentsareoutofallowable ranges.Thesetemperature measurements are used to compute the contributions of the instrumentcomponentstotheICTradiometricmodel. This flaghasarangeof0–1,andthe l1b_qualbitassignmentisdefinedinTable1.

Table14:InvalidInstrumentTemperatureQualityFlagvaluesanddescription

Value Description0 Allinstrumenttemperatureswithinrespectivethresholds1 Instrumenttemperatureoutsideofrespectivethreshold

17

Table15:Validrangesforinstrumenttemperatures

Temperature MinValue MaxValueT_PRT1 270(TBR) 290(TBR)T_PRT2 270(TBR) 290(TBR)OMA_structure_input_1 270(TBR) 290(TBR)OMA_structure_input_2 270(TBR) 290(TBR)SSM_scan_mirror 270(TBR) 290(TBR)beamsplitter_1 270(TBR) 290(TBR)SSM_scan_mirror_baffle 270(TBR) 290(TBR)

2.8 ExcessThermalDriftThe Excess Thermal Drift flag is intended to identify the situation when the measuredtemperatureofanyinstrumentcomponentshasdriftedgreaterthantheallowablelimit.Thesetemperature measurements are used to compute the contributions of the instrumentcomponentstotheICTradiometricmodel. This flaghasarangeof0–1,andthe l1b_qualbitassignmentisdefinedinTable1.

Table16:ExcessThermalDriftQualityFlagvaluesanddescription

Value Description0 Noexcessthermaldriftofinstrumenttemperatures1 Thermaldriftbetweenmeasurementsexceedsrespectivethreshold

Table17:ExcessThermalDriftThreshold

Temperature ThresholdT_PRT1 +/-1.0(TBR)T_PRT2 +/-1.0(TBR)OMA_structure_input_1 +/-1.0(TBR)OMA_structure_input_2 +/-1.0(TBR)SSM_scan_mirror +/-1.0(TBR)beamsplitter_1 +/-1.0(TBR)SSM_scan_mirror_baffle +/-1.0(TBR)

2.9 FCEDetectedThisflaghasarangeof0–1,andthel1b_qualbitassignmentisdefinedinTable1.ThisflagisnotimplementedfortheVersion1.0release.

Table18:FCEDetectedQualityFlagvaluesanddescription

Value Description0 Nofringecounterrordetected1 Fringecounterrordetected

2.10 FCECorrectionFailedThisflaghasarangeof0–1,andthel1b_qualbitassignmentisdefinedinTable1.ThisflagisnotimplementedfortheVersion1.0release.

18

Table19:FCECorrectionFailedQualityFlagvaluesanddescription

Value Description0 FCEcorrectionsuccessful1 FCEcorrectionfailed

2.11 NeonCalibrationQualityThisflaghasarangeof0–1,andthel1b_qualbitassignmentisdefinedinTable1.

Table20:NeonCalibrationQualityFlagvaluesanddescription

Value Description0 Lessthan25%oftheneoncalibrationdatasetvariedfromthemeanbygreaterthanthe

28ppmthreshold1 25%orgreateroftheneoncalibrationdatasetvariedfromthemeanbygreaterthanthe

28ppmthreshold

2.12 ISADegradedThe ISADegraded flag is intended to identify the situationwhen the inverse self-apodizationmatricesthatareusedintheself-apodizationcorrectionweregeneratedforametrologylaserwavenumber that differs from the currentmetrology laserwavenumber bymore than a pre-definedthreshold.This flaghasarangeof0–1,andthe l1b_qualbitassignment isdefinedinTable1.

Table21:ISADegradedQualityFlagvaluesanddescription

Value Description0 Current laserwavenumbervaluediffersby less than15ppmwithrespect to the laser

wavenumberusedtocalculatetheISAmatrices1 Currentlaserwavenumbervaluediffersby15ppmorgreaterwithrespecttothelaser

wavenumberusedtocalculatetheISAmatrices

2.13 L1aESMissingThis flaghasarangeof0–1, ispropagated fromthecorrespondingES/l1a_qual flag,andthel1b_qualbitassignmentisdefinedinTable1.

Table22:L1aESMissingQualityFlagvaluesanddescription

Value Description0 CompleteESinterferogrampacket1 Interferogrampacketwasnotreceived

2.14 BitTrimMismatchThis flaghasarangeof0–1, ispropagated fromthecorrespondingES/l1a_qual flag,andthel1b_qualbitassignmentisdefinedinTable1.

19

Table23:BitTrimMismatchQualityFlagvaluesanddescription

Value Description0 Bittrimsucceeded1 Bittrimfailed,toomuchortoolittlepackedinterferogramdata

2.15 ScanLineMissing8SecSciThis flaghasarangeof0–1, ispropagated fromthecorrespondingES/l1a_qual flag,andthel1b_qualbitassignmentisdefinedinTable1.

Table24:ScanLineMissing8SecSciQualityFlagvaluesanddescription

Value Description0 8-secsciencepacketavailableforthisscanline1 8-secsciencepacketunavailableforthisscanline

20

3 L1BtoSDRqualityflagcomparisonTable25:L1BtoSDRqualityflagcomparison,sortedbySDRQualityFlag.

RDR/SDR/GEO l1b_qualQualityFlag QualityVariable(Bit) QualityFlag(#ofbits) RelDataGap QF1_SCAN_CRISSDR

(B0)LWESMissing(1)*MWESMissing(1)*SWESMissing(1)*

B3

TimingSequenceError

QF1_SCAN_CRISSDR(B1)

NotimplementedinV1.0

LambdaMonitoredQuality



InvalidInstrumentTemperature


InvalidInstrumentTemperature(1) V1

ExcessThermalDrift


ExcessThermalDrift(1) V1

SuspectNeonCalibration


NeonCalibrationQuality(1) V1

LunarIntrusionForward

QF2_CRISSDR(B0)

LWLunarIntrusionDetected(1)MWLunarIntrusionDetected(1)SWLunarIntrusionDetected(1)

V1

LunarIntrusionReverse

QF2_CRISSDR(B1)

SDROverallQuality QF3_CRISSDR(B0-B1)

LWL1BQuality(2)MWL1BQuality(2)SWL1BQuality(2)

B3

InvalidGeolocation QF3_CRISSDR(B2)

GeoQuality(1)(TBD) B3

InvalidRadiometricCalibration

QF3_CRISSDR(B3-B4)

LWRadiometricCalibrationQuality(2)MWRadiometricCalibrationQuality(2)SWRadiometricCalibrationQuality(2)

V1

InvalidSpectralCalibration

QF3_CRISSDR(B5-B6)

LWSpectralCalibrationQuality(2)MWSpectralCalibrationQuality(2)SWSpectralCalibrationQuality(2)

V1

SDRFCECorrectionFailed

QF3_CRISSDR(B7)

FCECorrectionFailed(1)NotimplementedinV1.0

Day/NightIndicator QF4_CRISSDR(B0)


InvalidRDR QF4_CRISSDR(B1)

N/A

FCEDetected QF4_CRISSDR(B2)

FCEDetected(1)NotimplementedinV1.0

BitTrimFailed QF4_CRISSDR(B3)

BitTrim(1)* B3

ImaginaryRadianceAnomaly

QF4_CRISSDR(B4)

LWImaginaryRadianceAnomaly(1)MWImaginaryRadianceAnomaly(1)SWImaginaryRadianceAnomaly(1)

B3

ScanLineMissing8SecSci(1)* B3 ISADegraded(1) V1*replicatedfroml1a_qual

21

Table26:L1BtoSDRqualityflagcomparison,sortedbyL1BQualityFlag.

QualityFlag(#ofbits) Rel QualityFlag QualityVariable(BitAddress)

LWL1BQuality(2)MWL1BQuality(2)SWL1BQuality(2)

Beta3

SDROverallQuality QF3_CRISSDR(B0-B1)

GeoQuality(1) Beta3

InvalidGeolocation QF3_CRISSDR(B2)

LWRadiometricCalibrationQuality(2)MWRadiometricCalibrationQuality(2)SWRadiometricCalibrationQuality(2)

V1 InvalidRadiometricCalibration

QF3_CRISSDR(B3-B4)

LWSpectralCalibrationQuality(2)MWSpectralCalibrationQuality(2)SWSpectralCalibrationQuality(2)

V1 InvalidSpectralCalibration

QF3_CRISSDR(B5-B6)

LWImaginaryRadianceAnomaly(1)MWImaginaryRadianceAnomaly(1)SWImaginaryRadianceAnomaly(1)

Beta3

ImaginaryRadianceAnomaly

QF4_CRISSDR(B4)

LWLunarIntrusionDetected(1)MWLunarIntrusionDetected(1)SWLunarIntrusionDetected(1)

V1 LunarIntrusionForward

QF2_CRISSDR(B0)

LunarIntrusionReverse

QF2_CRISSDR(B1)

InvalidInstrumentTemperature(1) V1 InvalidInstrumentTemperature


ExcessThermalDrift(1) V1 ExcessThermalDrift


FCEDetected(1)NotimplementedinV1.0

FCEDetected QF4_CRISSDR(B2)

FCECorrectionFailed(1)NotimplementedinV1.0

SDRFCECorrectionFailed

QF3_CRISSDR(B7)

NeonCalibrationQuality(1) V1 SuspectNeonCalibration


ISADegraded(1) V1 N/A N/ANotimplementedinV1.0 LambdaMonitored

QualityQF1_SCAN_CRISSDR(B2)

NotimplementedinV1.0 TimingSequenceError


LWESMissing(1)*MWESMissing(1)*SWESMissing(1)*

Beta3

DataGap QF1_SCAN_CRISSDR(B0)

BitTrim(1)* Beta3

BitTrimFailed QF4_CRISSDR(B3)

ScanLineMissing8SecSci(1)* Beta3

N/A InvalidRDR QF4_CRISSDR(B1)

NotimplementedinV1.0 Day/NightIndicator QF4_CRISSDR(B0)

*replicatedfroml1a_qual

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4 GeolocationFlagDescriptions

Thederivationandmeaningofgeolocationqualityflagswillbedescribedinafutureversionofthis document. However there is a brief description of the meanings of the individualgeolocationflagsintheNASASNPPCrISLevel1BProductUsers’Guide,Version1.0.

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5 CaveatsandKnownIssues

Evaluationofanearlyreleasecandidate(v1.0RC6)indicatedthatflagsforQualityDegradedandRadQualDegradedincludefalsepositives.Thisissuewasaresultoffalsepositivedetectioninthe lunar intrusion check that was primarily occurring at the ends of the context granules,resultinginthemovingaverageforthespaceviewbeinglessthannominalforthefirst/lastfewscansofthegranulebeingcalibrated.

Inspection did not reveal any real issues for the radiances flagged as degraded in thesecases. Forthecasesreviewed,thiswasprimarilyanissuefortheSW,andFOV3inparticular,withmorefalsedegradedQFsneartheSouthPole.

Intermsofrootcause,itwasdeterminedthatthethresholdinthelunarintrusioncheckwassettootight,particularly fortheSW. Theshort-termsolution(v1.0RC7/RC8)wasto increasethethresholdsuch that these falsepositivesarenotoccurring,while the lunar intrusionsarestillsuccessfullydetected.

The long-term solution is to further refine the lunar intrusion check algorithm. The currentalgorithm is based on the IDPS method but has been modified to account for the issuesidentifiedinthatmethod,andstillincorporatestighterthresholdsinv1.0RC7/RC8thanusedintheIDPSsoftware.

nasa snpp cross track infrared sounder (cris) level 1b ... · quality = 2 (invalid) spectral...

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