Comparison of AIRS And CrIS Calibrated Radiance between May 2012 and May 2015.

Abstract:

The Atmospheric Infrared Sounder (AIRS) on EOS Aqua and the Cross-track Infrared Sounder (CrIS) on NPP Suomi are hyperspectral infrared sounders with similar objectives, similar specifications, and in polar orbits with the same 1:30PM ascending node. The AIRS data record started in 2002, CrIS started in 2012. After the AIRS data come to an end, CrIS and its follow-on are expected to continue the AIRS data record. The most direct verification that this data record is continued without artifacts, which may be misinterpreted as climate change, is the direct comparison of radiances. We compare AIRS and CrIS data for the 3 year period starting in May 2012 using daily random nadir samples. The comparison focuses on daily mean values and extreme values (10 and 90 percentiles) in the tropical, moderate and polar zones. We limit the comparison to three atmospheric window channel at 900 cm-1, 1232 cm-1 and 2508 cm-1, since they are representative of the three CrIS bands and because the three channels from AIRS and there equivalents from CrIS can be compared at the 50 mK level without an explicit correction for differences in their spectral response functions.