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Prasanjit Dash STAR/CIRA Alexander Ignatov STAR

Cal/Val QC/QA of SST, Aerosols and Clear Sky Radiances over Oceans NDE Preliminary Design Review, 22 March 2007, 9-11:30am, WWB Rm. 707. Global consistency of MetOp-A & NOAA18-15 AVHRR Clear Sky Brightness Temperatures using MODTRAN-4.2 forward RTM. Prasanjit Dash STAR/CIRA

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Prasanjit Dash STAR/CIRA Alexander Ignatov STAR

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  1. Cal/Val QC/QA of SST, Aerosols and Clear Sky Radiances over OceansNDE Preliminary Design Review, 22 March 2007, 9-11:30am, WWB Rm. 707 Global consistency of MetOp-A & NOAA18-15 AVHRR Clear Sky Brightness Temperatures using MODTRAN-4.2 forward RTM Prasanjit DashSTAR/CIRA Alexander IgnatovSTAR Acknowledgment John Sapper, OSDPD – Providing MUT AVHRR Data Yury Kihai, STAR/QSS – Archiving GDAS Data from NCEP Cross-platform consistency of AVHRR Clear Sky BT

  2. Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 f-RTM: OBJECTIVE Check consistency of TOA BTs in AVHRR Earth Emission Bands onboard MetOp-A & NOAA-KLMN by intercomparing RTM ‘forward simulations’ and ‘measurements’ Cross-platform consistency of AVHRR Clear Sky BT

  3. Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTMAPPROACH REALIZATION : Step 1 : SPATIAL MERGING OF AVHRR vs. NCEP • Atmo: T, RH, GP (Z), P • Surf: Ts Forward Simulation, 1cm-1 (MODTRAN 4.2) 5 UTCs for a Date Step 2 : Surf:Modeled Spectral Emissivity (1cm-1 intervals & 17 angles) Step 3 : Temporal Interpolation of forward RTC betw. 2 UTCs RESULTS Intercomparison (statistical analysis) forward model BT vs. gridded AVHRRs’ BT INPUT DATA : • AVHRR Brightness Temperatures from heritage • SST processor (Main Unit Task- MUT), NIGHT-TIME • NCEP GDAS profiles (atmosphere) • Emissivity (Fresnel’s law), Tsurface from NCEP (surface) Cross-platform consistency of AVHRR Clear Sky BT

  4. Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTM Step3: TEMPORAL INTERPOLATION Temporal Variation of Column Water Vapor (Feb 2007) Cross-platform consistency of AVHRR Clear Sky BT

  5. Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTM RESULTS: BT (RTM – MetOp-A AVHRR) MAPS Channel 3B (RTM - AVHRR) Channel 4 (RTM - AVHRR) Channel 5 (RTM - AVHRR) BT (RTM – AVHRR) CAN BE PLOTTED AS : • HISTOGRAM OR AS A FUNCTION OF : • LATITUDE • VIEW ZENITH ANGLE • COLUMN WATER CONTENT • AIR-SEA TEMPERATURE DIFFERENCE • WIND SPEED Cross-platform consistency of AVHRR Clear Sky BT

  6. Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTM RESULTS: BT (AVHRR – proxy) as a function of View Zenith Angle MetOp-A, NOAA18 through NOAA15 AVHRR - RTM AVHRR – NCEP RTG SST AVHRR RSR (ncdc.noaa.gov) Cross-platform consistency of AVHRR Clear Sky BT

  7. Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTM RESULTS: BT (AVHRR - proxy) as a function of VZA vs. SNO AVHRR Channel 3B - RTG DETECTION OF SENSOR PROBLEM USING:SNO MATCH-UPS Channel 3B (NOAA 18 vs. MetOp-A) DETECTION OF SENSOR PROBLEM USING:FORWARD_RTM APPROACH Channel 3B (AVHRR - RTM) Source: Intersatellite Instrument CharacteristicsPOES NOAA18 AVHRR and Metop-A AVHRR http://www.orbit.nesdis.noaa.gov/smcd/spb/calibration/icvs/n18-metopa-avhrr.html Cross-platform consistency of AVHRR Clear Sky BT

  8. Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTM RESULT HIGHLIGHTS Using RTM Forward RTC as an expected state for TOA BT is an effective tool for monitoring (QC) • Ch-4 shows excellent consistency for 5 platforms and Ch-5 too … • Ch-3B of AVHRR onboard MetOp-A and NOAA-16 show anomalous pattern • cause being explored – RSR ? Or Cal ? Or anything else ? Cross-platform consistency of AVHRR Clear Sky BT

  9. BACK-UP SLIDES Cross-platform consistency of AVHRR Clear Sky BT

  10. Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTM RESULTS: BT (RTM – AVHRR) as a function of #SSTOBS in GRID Channel 3B Channel 4 Channel 5 Cross-platform consistency of AVHRR Clear Sky BT

  11. Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTM RESULTS: BIAS and STANDARD DEVIATION, e.g., NOAA-18 NOAA-18, STATISTICS FROM GRIDS WITH STATISTICALLY SIGNIFICANT #OBS e.g., >= 8 Channel 3B: BIAS: 0.86 STDV: 0.55 Channel 4: BIAS 0.18 STDV: 0.67 Channel 5: BIAS:1.07 STDV: 0.67 Cross-platform consistency of AVHRR Clear Sky BT

  12. Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTM Step 2 :EMISSIVITY MODELING Emissivity angular variation Validation against Masuda et al. (1988) Emissivity spectral variation for MetOp-A AVHRR 3B, 4, 5 channels Ch-4 Ch-5 Ch-3B Cross-platform consistency of AVHRR Clear Sky BT

  13. Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTM RESULTS: BT (RTM – AVHRR) as a function of View Zenith Angle MetOp-A, NOAA18 through NOAA15 Channel 3B (RTM - AVHRR) Channel 4 (RTM - AVHRR) Channel 5 (RTM - AVHRR) Cross-platform consistency of AVHRR Clear Sky BT

  14. Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTM AVHRR Relative Response Functions Channel 3B AVHRR Channel 3B Relative Response Functions (MetOp-A & NOAA 18-15) annotated over Mid-Latitude Summer Transmissivity Values calculated with MODTRAN at 1cm-1 Cross-platform consistency of AVHRR Clear Sky BT

  15. Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTM AVHRR Relative Response Functions Channel 4 AVHRR Channel 4 Relative Response Functions (MetOp-A & NOAA 18-15) annotated over Mid-Latitude Summer Transmissivity Values calculated with MODTRAN at 1cm-1 Cross-platform consistency of AVHRR Clear Sky BT

  16. Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTM AVHRR Relative Response Functions Channel 5 AVHRR Channel 5 Relative Response Functions (MetOp-A & NOAA 18-15) annotated over Mid-Latitude Summer Transmissivity Values calculated with MODTRAN at 1cm-1 Cross-platform consistency of AVHRR Clear Sky BT

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