V: Instrument & Product Calibration / Validation

1. V: Instrument & Product Calibration / Validation Alexander P. Trishchenko* (Environment Canada) Fuzhong Weng (NOAA) * on secondment from the Canada Centre for Remote Sensing, NRCan

2. Outline • EC PCW CalVal Plan • Calibration requirements for PCW imager vs GOES-R ABI • Planned instrument calibration approach for PCW • Inter-calibration with GEO and LEO, participation in GSICS • STAR CalVal Overview • IJPS Calibration • GOES/GOES-R • NPP/JPSS • Non-NOAA (FY-3/DMSP/NASA/Jason) • GSICS

3. PCW Imager Vs GOES-R/ABI Bands in Bold are Priority 1. The remaining bands are in priority 2 list

4. Calibration for PCW • Pre-launch characterization • Some limited capacity exist in Canada (ABB BOMEM, COMDEV, CSA DFL) • Co-operation with NOAA, NASA and NIST would be very helpful for pre-launch radiometric, geometric and spectral calibration of PCW imager • In-flight calibration • Solar, spectralon diffusor(s): frequent in the beginning, periodic during regular operations (limited by spectralon UV exposure) • Blackbody, every scene • Deep space counts (twice per scan) • Intercalibration between PCW imagers to ensure consistency in derived imagery and products • Lunar calibration – co-operation with NOAA and NASA would be very helpful • NOAA bias analysis using comparison with RTM results would be very useful

5. Intercalibration with LEO and GEO • PCW would significantly benefit from participation in the Global Space-based Inter-Calibration System (GSICS) • Improved quality of PCW imagery and products • Consistency between PCW and other satellite data • PCW can be intercalibrated against polar orbiters (LEO) as well as GEO • The Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission led by NASA could be of a unique value for absolute radiometric and spectral calibration

6. Temporal coverage map for PCW system (% of total time, 100% means 24hrs per day) VZA <700; 100% coverage >580N; ~ 50% for tropics; Up to 20% for tropical zone below equator Good opportunity for temporal and spatial collocation Trishchenko and Garand, 2010, JTECH, submitted

7. Imagery and Product Cal/Val • Part of the PCW Meteorological Product Application Processing Facility (MAPF) at EC. • L1 QC • Calibration monitoring • Geolocation monitoring • Operational product verification • Operational analysis and reporting statistics • Visual control • Cal/Val activities could be shared with NOAA • Science activities • Focused research in special areas of interest & products • Specialized product cal/val projects involving joint science teams • Partnering with CEOS WGCV and GSICS

8. NESDIS/STAR Operational Calibration • IJPS (NOAA/METOP) Calibration • TVAC analysis • Radiometric calibration • Calibration coefficients LUT and data sets • Spectral and spatial calibration • On-orbit verification and Long-term monitoring • GOES-R Calibration Working Group • Post-launch checkup • Vicarious calibration • NPP/JPSS Calibration • SDR Code processing and updates • On-orbit Verification • Long-term monitoring • Non-NOAA Instruments (FY-3/DMSP/GPM) • WMO GSICS Executive Chair and Coordination Center

9. The GOES-R Calibration Working Group Led by Dr. C. Cao • Verify and ensure well-calibrated, & well-navigated GOES-R L1b data for the life time of the instruments (ABI, GLM, and SWx) • Ensure Level 1B data quality. Provide technical oversight and IV&V for: • Radiometric calibration • Spectral calibration • Spatial calibration/navigation check • Independent verification of L1B data • Evaluate and mitigate instrument performance risks (e.g., possible striping, noise, cross-talk, RVS, spectral response uncertainty, etc) • Provide technical support to the Flight and Ground through PSE Radiometric Spectral Spatial

10. The GOES-R Calibration Working Group Expertise • Prelaunch calibration support (flight segment) • Test data analysis and instrument performance evaluation (bench and thermal vacuum) • Prelaunch test participation on-site at Rochester and Fort Wayne (w/ two CWG representatives) • SI traceability using NIST state-of-the-art technologies such as transfer radiometers (TXR, VXR) as well as SIRCUS characterization • Expertise include advanced degrees in opto-electronics, physics, imaging science, software engineering, and Earth sciences. • Advisors from heritage GOES, POES, and NASA EOS programs • Members from NOAA, NASA, NIST, and MIT/LL • Ground systems • Calibration support to the operational processing system design and development • Postlaunch capability developments • On-orbit verification • Instrument performance evaluation • Anomaly diagnosis • Vicarious calibration • Operational longterm monitoring • Prototyping for GOES-R using current GOES data • GSICS collaboration From Meteorology to Metrology

11. Four Phases of Calibration/Validation 1. Pre-Launch (development and I&T) - CDRL peer review, PDR/CDR - Algorithm & calibration database development & verification - Data format/content/quality flags - Bench/TVAC tests and analysis - Trade studies and waivers - Validation capability development and preparation - Prelaunch SI traceability 2. Operational check-out (Post-Launch Tests) - Engineering tests to ensure specification compliance - Calibration processing - Anomaly analysis 3. On-orbit verification (Environmental cal. initialization) - Instrument characterization - Sensor artifact study and correction - Algorithm adjustment - Inter-comparison between satellites, and with NWP models - Both SDR and EDR Validation 4. Long-Term Monitoring (Mission operational life) -Routine monitoring of instrument performance -Inter-satellite comparison and NWP models

12. Spectral Response Function Analysis • Two sets of pre-launch spectral response functions (SRFs) for ABI • The CIMSS version and the CWG version • Quantified the differences between them and their impacts through spectral analysis using Hyperion and IASI spectra • Working with AWG to assess impact (Walter Wolfe & Jamie Daniels) Hyperion Derived (VNIR) Targets IASI Derived (IR) Targets

13. Spectral Response Function Analysis • Differences found between the two sets of SRFs • Solar Bands: differences ranged from near 0 to approaching 2% TOA reflectance • IR Bands: differences from near 0 to >1K in brightness temperature • Recommendation: users should use a consistent set of SRF, until the flight model SRF becomes available VNIR Results IR Results

14. NIST Activities • Working with NIST and ITT on the deployment of NIST instruments • VXR: ~ Spring 2011 • TXR: ~ 2010 • SIRCUS: in discussion with ITT • Thermal Transfer Radiometer (TXR), Visible Transfer Radiometer (VXR), and ASD Spectrometer • Ensure prelaunch SI traceability • Spectral Irradiance and Radiance Responsivity Calibrations using Uniform Sources (SIRCUS) • Significantly improves solar band spectral response function characterization/validation • Straylight characterization • Capabilities for IR channels are being developed

15. GOES-R Ground System Support • Defining instrument calibration data sets • Calibration data files proposed • Once every two hours; one for each instrument • Example items: • Instrument temperatures • Calibration event data (e.g., internal target and space view counts) • Calibration data statistics (e.g., instrument noise) • Level 1b landmark data • Calibration data will go into GAS (GOES-R Access Subsystem, 7day storage), and CLASS (for long-term) • Collaborating with NSOF calibration specialists to ensure operational monitoring of: • Calibration-related instrument engineering and science data • L0-to-L1b data processing parameters • Work in process, not all instruments have passed CDR

16. Global Space-based Inter-Calibration System • What is GSICS? • Global Space-based Inter-Calibration System • Initiative of CGMS and WMO • An effort to produce consistent, well-calibrated data from the international constellation of operational meteorological satellites • What are the basic strategies of GSICS? • Best practices/requirements for prelaunch characterisation (with CEOS WGCV) • Improve on-orbit calibration by developing an integrated inter-calibration system • Initially by LEO-GEO Inter-satellite/inter-sensor calibration • This will allow us to: • Improve consistency between instruments • Produce less bias in Level 1 and 2 products • Retrospectively re-calibrate archive data • Better specify future instruments

17. GSICS organization • Organizations contributing to GSICS: CMA, CNES, EUMETSAT, ISRO, JAXA, JMA, KMA, NASA, NIST, NOAA, WMO • Overseen by GSICS Executive Panel Assisted by Research Working Group and Data management Working Group • GSICS activities rely on: • GSICS Coordination Centre (GCC) • operated by NOAA/NESDIS • Processing & Research Centres (GPRC) • operated by each satellite operator • Calibration Support Segments (CSS) • including field sites and laboratories GSICS as an element of the space-based component of the Global Observing System CoordinationCenter Calibration Support Segments (reference sites, benchmark measurements, aircraft, model simulations) Regional Processing Research Centers at Operational Space Agencies

18. Applications of GSICS • Quantify the differences – magnitude and uncertainty • Removethe differences – empirical or physical • Understandthe differences – root cause analysis and correction/prevention

19. GOES Imager 13.3 μm Channel SRF • GOES-13 PLT found Imager Band 6 cold bias of -2.4 K • Original proposal of a -4.7 cm-1 shift of SRF • Instrument vendor revised SRF, effectively shifted -1 cm-1 • NOAA implemented additional -2.1 cm-1 shift, eliminated bias and its dependence on scene temperature (not shown) GOES-13 Imager Band 6 spectral response functions, with (green) and without (blue) a -4.7 cm-1 shift, superimposed on spectral radiance for the U. S. Standard Atmosphere (red). GOES-13 Imager Band 6 spectral response functions, original (blue) and revised (red), superimposed on AIRS spectral radiance for the U. S. Standard Atmosphere (black). GOES-13 Imager Band 6 radiance difference (in terms of brightness temperature) from AIRS (blue) and IASI (red), two well calibrated hyperspectral instrument used as reference for GSICS.

20. GSICS Monitoring and Correction

21. Impact of GSICS Correction on GOES-12 Imager radiance Compared to CRTM, GOES-12 Imager Channel 6 bias was reduced from -2.55K before GSICS correction to -0.11K after T. Zhu, F. Weng

22. Impact of GSICS Correction for GOES-12 Imager radiance on GFS forecast GOES-12 imager with and without GSICS bias correction Anomaly Correlation for 500 mb height over tropics (left) and NH (right) T. Zhu, F. Weng

23. Impact of GSICS Correction for SEVIRI radiance on GFS forecast MSG SEVIRI CSR with and without GSICS bias correction Anomaly Correlation for 500 mb height over tropics (left) and NH (right) T. Zhu, F. Weng

24. Double Difference Technique: A Robust Way for Estimating Sensor to Sensor biases • It reduces the impact related to temporal difference when two instruments have distinct orbits • It reduces the errors related to forward models and from forecast models • It works in the region where the forward model has the same error characteristics • Assumptions: • The same temporal difference from observations and simulations • Negligible forward model biases for two instruments

25. SSMIS TDR Anomalies ( Observation – Simulation ) 54.4 GHz V 55.5 GHz V

26. Double Difference Technique (DDT)

27. Summary • PCW calibration can be leveraged from NOAA GOES-R calibration components • GSICS baseline algorithms can be refined for PCW applications