NASA, CGMS-41, July 2013

Coordination Group for Meteorological Satellites - CGMSCoordination Group for Meteorological Satellites - CGMS

Calibration/validation of Operational Instruments at NASA Langley Research Center, NASA

Goddard Space Flight Center and the University of Wisconsin

Presented to CGMS-41 Working Group II, WGII/3

James J. Butler1, Jack Xiong1, David R. Doelling2, David E. Tobin3

1NASA Goddard Space Flight Center2NASA Langley Research Center

3University of Wisconsin

NASA, CGMS-41, July 2013

Coordination Group for Meteorological Satellites - CGMS

Uniform radiance scenes show

little difference

Clear areasnear bright clouds

show larger differences

-300 -200 -100 0 100 200 300-6x10-5

-4x10-5

-2x10-5

0

2x10-5

4x10-5

6x10-5

PS

F

pixel position

peak=1.0

A

Elliptical_Gauss

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, Arata Okuyama (JMA) provided the MTSAT-2 commissioning images, that made this PSF correction possible

MTSAT-2 imageDec 21, 2010, 0:30 GMT

MTSAT-1R minus MTSAT-2Dec 21, 2010, 0:30 GMT

MTSAT-1R and MTSAT-2 Inter-comparison (NASA Langley)

NASA, CGMS-41, July 2013

Coordination Group for Meteorological Satellites - CGMS

• 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%

Meteosat-9 0.65µm gain comparison using the MODIS Aqua 0.65µm band as reference (NASA Langley)

NASA, CGMS-41, July 2013

Coordination Group for Meteorological Satellites - CGMS

CrIS/AIRS brightness T (BT) intercomparisons using Simultaneous Nadir Overpasses (SNOs) over a wide range of latitude and longitude

CrIS/IASI BT intercomparisons using Simultaneous Nadir Overpasses (SNOs) over northern, high latitude, nadir views

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)

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

Suomi NPP CrIS intercomparisons with EOS AIRS, Metop IASI and Suomi NPP VIIRS (U. of Wisconsin) (1 of 2)

NASA, CGMS-41, July 2013

Coordination Group for Meteorological Satellites - CGMS

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

Suomi NPP CrIS intercomparisons with EOS AIRS, Metop IASI and Suomi NPP VIIRS (U. of Wisconsin) (2 of 2)

NASA, CGMS-41, July 2013

Coordination Group for Meteorological Satellites - CGMS

Solar diffuser reflectance degradation (H factor) vs time on-orbit using the on-board Solar Diffuser Stability Monitor

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

a.

b.

c.

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

Curves: SD calibration gain trending Points: Lunar calibration gain trending

a. M1: 412nm; M2: 445nm; M3: 488nm

b. 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

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)