Abstract
On November 18, 2017, the JPSS-1 satellite was launched into polar orbit and renamed NOAA-20. Included in its instrument suite is the Cross-Track Infrared Sounder (CrIS) that collects spectra used for atmospheric soundings with twice-daily global coverage. CrIS creates radiometrically calibrated spectra at 0.625 cm-1 resolution covering three spectral regions from 4 to 15 micrometers, with a 3x3 focal plane array and a nadir footprint of 14 km. NOAA-20 joined the orbit of its predecessor, Suomi National Polar-orbiting Platform (SNPP), with a half-orbit delay to provide better near-nadir coverage for the globe. NOAA-20 CrIS is a copy of the CrIS instrument on SNPP with a few electronics upgrades. The SNPP CrIS has performed well over its six years on orbit and continues to collect valuable data. NOAA-20’s CrIS data is in provisional status during further comparisons before an expected upgrade to full operational status later in 2018.
The NOAA-20 CrIS sensor had extensive ground calibration and has been undergoing further on-orbit validation since data collection began on January 4, 2018. Performance optimization on orbit resulted in only small changes to select pre-launch settings due to the robust on-ground calibration. In addition, on-orbit CrIS noise levels are similar to on-ground testing. This presentation will cover the results of JPSS-1/NOAA-20 CrIS noise characterization, calculated as the Noise Equivalent change in Radiation (NEdN), from both on-ground and on-orbit testing. In summary, the NOAA-20 CrIS instrument has performed well to date, meeting specified NEdN requirements. It performs comparable to SNPP CrIS, which still meets NEdN requirements. In addition, the relative responsivity (RR) of the NOAA-20 detectors has been tracked since on-orbit data collection began. RR was calculated as the difference between detector responses when viewing deep space and internal calibration targets. The NOAA-20 CrIS RR has thus far been stable after instrument optimization updates were applied on-orbit. The SNPP CrIS has performed very well in regards to RR—values are within 2% of initial RR for all but the shortest wavelengths, which have shown RR degradation of no more than 6% over the spacecraft lifetime. The latest updates on NOAA-20 and SNPP CrIS NEdN and RR will be included.
Calibration and On-Orbit Validation of the NOAA-20 CrIS Interferometer
On November 18, 2017, the JPSS-1 satellite was launched into polar orbit and renamed NOAA-20. Included in its instrument suite is the Cross-Track Infrared Sounder (CrIS) that collects spectra used for atmospheric soundings with twice-daily global coverage. CrIS creates radiometrically calibrated spectra at 0.625 cm-1 resolution covering three spectral regions from 4 to 15 micrometers, with a 3x3 focal plane array and a nadir footprint of 14 km. NOAA-20 joined the orbit of its predecessor, Suomi National Polar-orbiting Platform (SNPP), with a half-orbit delay to provide better near-nadir coverage for the globe. NOAA-20 CrIS is a copy of the CrIS instrument on SNPP with a few electronics upgrades. The SNPP CrIS has performed well over its six years on orbit and continues to collect valuable data. NOAA-20’s CrIS data is in provisional status during further comparisons before an expected upgrade to full operational status later in 2018.
The NOAA-20 CrIS sensor had extensive ground calibration and has been undergoing further on-orbit validation since data collection began on January 4, 2018. Performance optimization on orbit resulted in only small changes to select pre-launch settings due to the robust on-ground calibration. In addition, on-orbit CrIS noise levels are similar to on-ground testing. This presentation will cover the results of JPSS-1/NOAA-20 CrIS noise characterization, calculated as the Noise Equivalent change in Radiation (NEdN), from both on-ground and on-orbit testing. In summary, the NOAA-20 CrIS instrument has performed well to date, meeting specified NEdN requirements. It performs comparable to SNPP CrIS, which still meets NEdN requirements. In addition, the relative responsivity (RR) of the NOAA-20 detectors has been tracked since on-orbit data collection began. RR was calculated as the difference between detector responses when viewing deep space and internal calibration targets. The NOAA-20 CrIS RR has thus far been stable after instrument optimization updates were applied on-orbit. The SNPP CrIS has performed very well in regards to RR—values are within 2% of initial RR for all but the shortest wavelengths, which have shown RR degradation of no more than 6% over the spacecraft lifetime. The latest updates on NOAA-20 and SNPP CrIS NEdN and RR will be included.