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Uniform radiance scenes show little difference

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Uniform radiance scenes show little difference

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  1. Calibration/validation of Operational Instruments at NASA Langley Research Center, NASA Goddard Space Flight Center and the University of WisconsinPresented to CGMS-41 Working Group II, WGII/3James J. Butler1, Jack Xiong1, David R. Doelling2, David E. Tobin31NASA Goddard Space Flight Center2NASA Langley Research Center3University of Wisconsin

  2. MTSAT-1R and MTSAT-2 Inter-comparison (NASA Langley) MTSAT-1R minus MTSAT-2 Dec 21, 2010, 0:30 GMT MTSAT-2 image Dec 21, 2010, 0:30 GMT Uniform radiance scenes show little difference Clear areas near bright clouds show larger differences Develop MTSAT-1 point spread function (PSF) to subtract contribution from area surrounding pixel MTSAT-1R & MODIS Aqua comparison before PSF correction MTSAT-1R & MODIS Aqua comparison after PSF correction This is a GSICS success story, ArataOkuyama (JMA) provided the MTSAT-2 commissioning images, that made this PSF correction possible

  3. Meteosat-9 0.65µm gain comparison using the MODIS Aqua 0.65µm band as reference (NASA Langley) • MODIS Terra/Met-9 ray-match inter-calibration (first inter-calibrate MODIS Terra to MODIS Aqua using SNOs over poles) • Aqua-MODIS/Met-9 ray-match inter-calibration • Deep Convective Calibration using MODIS Aqua/Met-9 DCC reference radiance to predict MET-9 DCC radiance • Libya-4 Daily Exo-atmospheric Radiance Model (DERM) (DERM built using reference GEO inter-calibrated with MODIS Aqua, then use DERM to predict target GEO) • SCIAMACHY/Met-9 ray-match inter-calibration (first inter-calibrate SCIAMACHY to MODIS Aqua using SNOs) Mean gains are within 1%

  4. Suomi NPP CrISintercomparisons with EOS AIRS, Metop IASI and Suomi NPP VIIRS (U. of Wisconsin) (1 of 2) • CrIS/AIRS brightness T (BT) intercomparisons using Simultaneous Nadir Overpasses (SNOs) over a wide range of latitude and longitude Comparison of the log scale BT distributions (i.e. left 6 plots) leads to mean BT difference distribution agreements of 0.12⁰ or better (i.e. right 6 plots) • CrIS/IASI BT intercomparisons using Simultaneous Nadir Overpasses (SNOs) over northern, high latitude, nadir views Comparison of CrIS and IASI mean BTs from northern SNOs from April 2012 to November 2012 Weighted mean CrIS/IASI BT differences and uncertainties are less than a few tenths K Similar results obtained using southern SNOs

  5. Suomi NPP CrISintercomparisons with EOS AIRS, Metop IASI and Suomi NPP VIIRS (U. of Wisconsin) (2 of 2) • CrIS/VIIRS brightness T (BT) intercomparisons Time series of daily mean BT differences between VIIRS and CrIS from February 2012 to April 2013 for VIIRS bands at 4µm, 10.8µm, and 12µm Discontinuities due to adjustment to VIIRS blackbody T knowledge (March 2012) and planned VIIRS blackbody warm up/cool down linearity tests Since April 2012, the mean BT differences are less than 0.1K and are very stable Scan angle, scene T and orbit phase effects on VIIRS and CrIS BTs are being studied to fully understand instrument performance

  6. b. a. SNPP VIIRS has shown large gain degradation (1/F factor) in the near infrared and shortwave infrared vs time on-orbit due to WOx contamination incurred during fabrication of the telescope mirrors SNPP VIIRS gains trended over the mission using the on-board Solar Diffuser (SD) and near-monthly views of the ~51° phase Moon (NASA Goddard) Solar diffuser reflectance degradation (H factor) vs time on-orbit using the on-board Solar Diffuser Stability Monitor c. • SDSM ratios measurements of the solar illuminated diffuser and the Sun • SNPP VIIRS SD degradation is similar to that of MODIS Terra and Aqua with larger degradation seen at lower wavelengths • Curves: SD calibration gain trending • Points: Lunar calibration gain trending • M1: 412nm; M2: 445nm; M3: 488nm • M4: 555nm; I1: 640m; M5: 672nm; M6: 746nm; M7: 865nm; I2: 65nm • c. M8: 1240nm; M9: 1378nm; I3: 1610nm; M10: 1610nm; M11: 250nm Note: the VIIRS Sensor Data Record is corrected for mirror reflectance degradation in the affected bands

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