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NOAA-18 Instrument Calibration and Validation Briefing

NOAA-18 Instrument Calibration and Validation Briefing. NOAA/NESDIS/Office of Research and Applications As of the Week of June 6-10, 2005 For archived activities and latest news, please visit http://www.orbit.nesdis.noaa.gov/smcd/spb/n18calval. NOAA-18 Instrument Payload.

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NOAA-18 Instrument Calibration and Validation Briefing

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  1. NOAA-18 Instrument Calibration and Validation Briefing NOAA/NESDIS/Office of Research and Applications As of the Week of June 6-10, 2005 For archived activities and latest news, please visit http://www.orbit.nesdis.noaa.gov/smcd/spb/n18calval

  2. NOAA-18 Instrument Payload We focus on these instruments: • AVHRR/4 Advanced Very High Resolution Radiometer • HIRS/4 High Resolution Infrared Sounder • AMSU-A Advanced Microwave Sounding Unit-A • MHS Microwave Humidity Sounder • SBUV/2 Solar Backscattered Ultraviolet Radiometer

  3. Calibration and Validation Legend • PRT: Platinum Resistance Thermometers • NEDN/T: Noise Equivalent Delta Radiance/Temperature • ATOVS: Advanced TIROS Operational Vertical Sounder (TOVS) • TOAST: Total Ozone Analysis using SBUV/2 and TOVS • MSPPS: Microwave Surface and Precipitation Product System • NDVI: Normalized Difference Vegetation Index • SST: Sea Surface Temperature • UV: Ultraviolet • TPW: Total Precipitable Water • CLW: Cloud Liquid Water

  4. ORA NOAA-18 Instrument Cal/Val Mission Goals • Monitor and improve NOAA-18 instrument post-launch calibration • Assess and quantify instrument noises though analyzing calibration target counts and channel measurements • Monitor possible instrument anomaly and provide recommended solution • Quantify satellite navigation and geolocation errors • Characterize other biases in radiance and products such as cross-track asymmetry through forward modeling and inter-satellite calibration • Validate NESDIS NOAA-18 products (ATOVS and MSPPS, TOAST, UV index, NDVI, SST) for operational implementation • Provide early demonstration and assessments of NOAA-18 data for improving numerical weather prediction through JCSDA

  5. Mitch Goldberg: ORA/SMCD Division Chief, - Management and Technical Oversight Fuzhong Weng: ORA/SMCD/Sensor Physics Branch Chief and NOAA-18 cal/val team leader. Changyong Cao: HIRS instrument calibration Fred Wu: AVHRR VIS/IR instrument calibration Tsan Mo: AMSU/MHS instrument calibration Jerry Sullivan: AVHRR thermal channel calibration/ NDVI validation Tony Reale: HIRS/AMSU sounding channel/products validation Mike Chalfant: HIRS/AMSU sounding channel/products validation Ralph Ferraro: AMSU/MHS window channels/MSPPS products validation Larry Flynn: SBUV product validation Tom Kleespies: AMSU on-orbit verification Hank Drahos: Sounding product validation Dan Tarpley: AVHRR product NDVI monitoring John LeMashall: NWP validation Our Team

  6. HIRS Cal/Val News • HIRS/4 longwave channels (1 - 12) do not meet NEDN specification • More channel 1 scene counts are out of limits (-4095 to +4095). This will make difficult to assess HIRS noise value • Channel 12 (water vapor) is noisy, compared with NOAA-17 HIRS-3 at the same day of observation • Noise issues are being investigated • HIRS noise continues the same level

  7. HIRS/4 On-Orbit NEDN (6/14/2005) On-orbit NEDN needs to be fully assessed and is needed for NCEP data assimilation system and physical sounding retrieval system Red: channel noise can not be assessed Yellow: Noise level is assessed but out of spec.

  8. NOAA-18/HIRS Sample Orbit (June 7, 2005) Brightness Temperature for 19 IR channels ch1 ch2 ch3 ch4 ch5 ch6 ch7 ch8 ch9 ch10 ch11 ch12 ch13 ch14 ch15 ch16 ch17 ch18 Chs 1-12 longwave channels do not meet the spec Ch 12 for water vapor

  9. Compare with HIRS/NOAA-17sample orbit June 7, 2005

  10. AVHRR Cal/Val News • ORA AVHRR calibration algorithms work well • The blackbody temperature changes are monitored and shows in a small range of variability (only 2K) • Thermal channel (3-5) calibration is healthy • Wu’s Vis/IR calibration algorithms are working well • AVHRR NDVI products from NOAA-18 are of the similar quality to NOAA-16’s due to robust visible channel calibration • AVHRR geolocation error • 3 pixels (N-S) and 2 pixels (E-W) offsets are identified using the NDVI vegetation index as a land-sea tag

  11. AVHHR Thermal Channel Assessment PRT temperature is used to convert the count to brightness temperature using Planck function. If PRT temperature and scene counts are strongly linearly correlated, illustrating healthy thermal channel calibration

  12. NOAA-18 AVHRR derived NDVI is based on NOAA-16 vicarious calibration algorithm. This NDVI product is selected for our initial assessments of visible channel calibration because it uses both visible/near infrared channel data. It is a good indicator from our previous AVHRR experience if it shows consistent patterns. Since NOAA-18 has no on-board visible channel calibration. We normally wait for at least 6 months after launch to make vicarious calibration meaningful.

  13. AVHRR Geolocation Error AVHRR geolocation error is showed as offsets in north and south (3 pixels), east and west (2 pixels) directions

  14. AMSU Cal/Val News • AMSU-A NEDT on orbit is calculated and shows nearly all channel meet specification • AMSU post-launch calibration parameter information data base (CPIDS) were successfully updated for larger cold space calibration counts • AMSU-A2 cold space calibration count errors tolerance is increased from 25 counts to 50 counts • Overall AMSU calibration algorithms are healthy with reasonable gains, and variability in cold and warm calibration targets • AMSU-A channel 1 and 2 show some cross-scan asymmetry, similar to previous AMSU • Reasonable AMSU TPW and CLW product quality

  15. AMSU-A On-Orbit NEDT

  16. N18 vs. N16 – 05/25/05Total Precipitable Water

  17. Note asymmetry affects: More clouds on right side of scan. Need to update asymmetry coefficients. N18 vs. N16 – 05/25/05Cloud Liquid Water

  18. MHS Cal/Val News • The NOAA-18 MHS NEDT for each channel was calculated and is better than AMSU-B • MHS looks overall nominal except for a possible slight warm bias for the 183 +/- 1 and +/- 3 GHz channels. • MHS produces robust rainfall products and detect more light precipitation

  19. MHS On-Orbit NEDT MHS AMSU-B

  20. SBUV/2 Status • SBUV/2 is making some measurements in its standard operating mode • Ozone retrieval is performed. The change in total ozone behavior yesterday is probably related to a test switching from anode to cathode mode for the PMT

  21. Overall Summary • Most instruments are meeting specification with the current exception of HIRS • AMSU-A noise performance is exceptional • AVHRR NOAA-18 NDVI product appear to be consistent with NOAA-16 • MHS hydrological parameters (rainfall, total precip. water) appear to be better quality than AMSU-B (MHS noise is lower than AMSU-B) • AVHHR geolocation error is under investigation

  22. Next Step • Continue monitoring HIRS/4 noises • Quantify the instrument biases through rigorous forward calibration and inter-satellite calibration using simultaneous nadir overpassing (SNO) method • Assess the AMSU cross-track asymmetry for better cloud and rainfall products

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