## 3 Science Data Product Performance
### The CrIS/ATMS Instruments and Science Data Products
#### 3.2.1 The NUCAPS CrIS/ATMS EDR Products  
The NUCAPS algorithm is built upon heritage from the Atmospheric Infrared Sounder (AIRS) science team retrieval algorithm [83]. In addition to temperature, water vapor, and ozone products, the NUCAPS system operationally produces several trace gas products (e.g., CO, CH\({}_{4}\), CO\({}_{2}\), Volcanic SO\({}_{2}\)) from the CrIS/ATMS instruments. CrIS radiances are also used to produce near-real-time Outgoing Longwave Radiation (OLR) product. CrIS-derived OLR values are estimated as a weighted linear combination of CrIS-adjusted \"pseudo channel\" radiances. The estimation of OLR on a near-real-time basis provides a unique perspective for studying the variability of Earth's current atmospheric radiation budget [86]. The CrIS instrument NSR/FSR observations have been applied to NUCAPS retrieval algorithm to provide temperature, moisture, ozone profiles, and atmospheric trace gas profiles [84]. The full spectral resolution coupled with low noise in all three bands enable high quality CO and other trace gas retrievals [87]. The FSR observations allow discriminating very strong water lines in the MWIR and this leads to better derivation of upper tropospheric humidity. The increased spectral resolution also improves the calibration of the SWIR and improve temperature sounding, which, in turn, leads to improved sounding products [88]. The NUCAPS algorithm has been adapted as an enterprise solution to work on S-NPP and NOAA-20 CrIS/ATMS, AIRS/AMSU-A, and Meteorological Operational Satellite Program (MetOp) Infrared Atmospheric sounder (IASI)/AMSU-A/AMSU-B instrument complements. The algorithm has been evolved and evaluated over the years using the data from the hyper-spectral IR instruments and using associated MW instruments. The temperature, water vapor, and ozone retrievals have been validated for AIRS [89; 90], IASI [91], and CrIS [92; 93; 94; 95]. The CO derived from full resolution SNPP and NOAA-20 CrIS SDR has reached provisional maturity, while CO\({}_{2}\) and CH\({}_{4}\) remain at beta maturity [4]. Tables 10 and 11 show the S-NPP NUCAPS products performance for Temperature/Moisture Profiles and for Trace Gases and OLR Products, respectively. Figure 11: CrIS NSR/FSR. The full spectral resolution coupled with incredibly low noise in all three bands enables high quality CO and other trace gas retrievals. (Figure courtesy: [PERSON], STAR CrIS SDR team). Figure 12 comprises a suite of images from JPSS products; VIIRS Active Fire (a), VIIRS AOD (b), as well as the CO derived from CrIS/NUCAPS at 500 mb (c) and 700 mb (d), over the severe fires in California on 09 November 2018. The retrieved CO product from NUCAPS, while showing a distribution consistent with the fire and smoke observed from VIIRS, also provides information about the vertical distribution and transport of the CO over the downwind regions. NUCAPS Sounding EDRs derived from various satellite missions (S-NPP and NOAA-20 CrIS/ATMS; Aqua-AIRS/AMSU-A; MetOp-A, B, IASI/AMSU-A/AMSU-B) allow for inter-comparison of the products and enterprise validations using common ground truth measurements [89; 90; 96], development of blended products for consistent mission-agnostic data products, and establishment of future objective requirements.