Reprocessing of Suomi NPP CrIS Sensor Data Records to Improve the Radiometric and Spectral Long-Term Accuracy and Stability

Abstract

Since early 2012, the cross-track infrared sounder (CrIS) on board the Suomi National Polar-orbiting Partnership (S-NPP) satellite has continually provided the hyperspectral infrared observations for profiling atmospheric temperature, moisture, and greenhouse gases. In this study, the CrIS sensor data record (SDR) data are improved for climate applications with its fine-tuning of calibration coefficients in an NOAA reprocessing project. A specific software system was developed to reprocess the CrIS SDR. This software system was updated with a new calibration algorithm, nonlinearity, and geolocation to improve the SDR data quality and long-term consistency. The calibration coefficients are refined with the latest updates, which were used to calibrate the latest operational SDR products and replace those in the engineering packet (EP) in the raw data record (RDR) data stream. The resampling wavelength Manuscript received September 8, 2020; revised January 19, 2021; accepted February 9, 2021. This work was supported by the National Oceanic and Atmospheric Administration JPSS Office under Contract ST133017CQ0050. (Corresponding author: Yong Chen.) Yong Chen, Flavio Iturbide-Sanchez, Changyong Cao, and Satya Kalluri are with the Center for Satellite Applications and Research, National Environmental Satellite, Data, and Information Service (NESDIS), National Oceanic and Atmospheric Administration, College Park, MD 20740 USA (e-mail: [email protected]; [email protected]; [email protected]; [email protected]). Denis Tremblay and Ninghai Sun are with the Global Science and Technology, Inc., Greenbelt, MD 20770 USA (e-mail: [email protected]; [email protected]). David Tobin and Henry E. Revercomb are with the Space Science and Engineering Center, University of Wisconsin, Madison, WI 53706 USA (e-mail: [email protected]; [email protected]). Larrabee Strow is with the Department of Physics, University of Maryland at Baltimore County, Baltimore, MD 21250 USA (e-mail: [email protected]). Likun Wang and Bin Zhang are with the Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20740 USA (e-mail: [email protected]; [email protected]). Daniel L. Mooney is with the Massachusetts Institute of Technology Lincoln Laboratory, Lexington, MA 02421 USA (e-mail: [email protected]). David Johnson is with the NASA Langley Research Center, Engineering Directorate, Hampton, VA 23681 USA (e-mail: [email protected]). Joe Predina is with Logistikos Engineering LLC, Fort Wayne, IN 46845 USA (e-mail: [email protected]). Lawrence Suwinski is with L3Harris Technologies, Inc., Fort Wayne, IN 46818 USA (e-mail: [email protected]). Lihang Zhou is with Joint Polar Satellite System (JPSS), NOAA/NESDIS, Greenbelt, MD 20771 USA (e-mail: [email protected]). Color versions of one or more figures in this article are available at https://doi.org/10.1109/TGRS.2021.3060639. Digital Object Identifier 10.1109/TGRS.2021.3060639 was updated based on the metrology laser wavelength and resulted in zero sampling error in the spectral calibration. All the historical SDRs (from February 2012 to March 2017) were generated with the same calibration coefficients and same version of the processing software system, resulting in improved accuracy and stability in terms of spectral and radiometric calibration during the CrIS lifetime mission. The quality of the reprocessed CrIS SDR data at nominal spectral resolution (NSR) is assessed in terms of its radiometric and spectral calibration. Comparisons against the operational SDR data are carried out to demonstrate the improved long-term stability of the reprocessed CrIS SDR data. Overall radiometric biases are found to be small and highly stable over the instrument mission, the FOV-to-FOV differences are less than ∼10 mK, and much better than that from the operational SDR data. It is shown that the CrIS metrology laser wavelength varies within 4 ppm as measured by the neon calibration system. The reprocessed SDR data have spectral errors less than 0.5 ppm, which is much better than the operational SDR data with about 4 ppm. This baseline version of the reprocessed SNPP CrIS SDR data is suitable for long-term climate monitoring and model assessments and can provide an infrared reference observation to assess other narrowor broadband infrared instruments’ calibration accuracy.