NUCAPS Hyperspectral Infrared Atmospheric Sounding Products: Recent Algorithm Improvements and Product Updates for JPSS-CrIS and MetOp-IASI.

The NOAA Unique Combined Atmospheric Processing System (NUCAPS), operated by the National Oceanic and Atmospheric Administration (NOAA), produces vertical profiles of temperature, water vapor, ozone, and a variety of trace gas products (e.g., CO, CH4, and CO2) using the Cross-track Infrared Sounder (CrIS) and the Advanced Technology Microwave Sounder (ATMS) aboard the JPSS series of satellites (NOAA-20, NOAA-21). The system also generates consistent products from the Meteorological Operational Satellite Program (MetOp-B/C) Infrared Atmospheric Sounder (IASI) hyperspectral sounder radiances and the Advanced Microwave Sounding Unit (AMSU-A) and Microwave Humidity Sounder (MHS) instrument complements. The retrieval algorithm is built on the Atmospheric Infrared Sounder (AIRS) science team algorithm, and NOAA STAR led the efforts to develop, test, validate and refine the NUCAPS algorithm as an enterprise solution within the Hyperspectral Enterprise Algorithm Package (HEAP). In addition to NUCAPS atmospheric composition and trace gas products, the HEAP provides pre-processing and post-process capability for the NUCAPS and derives other hyperspectral radiance products such as thinned radiance data sets, principal component scores, and outgoing longwave radiation (OLR). Products are available worldwide through the NOAA Comprehensive Large Array-data Stewardship System (CLASS). The NUCAPS algorithm is also part of the Community Satellite Processing Package (CSPP) to disseminate products through Direct Broadcast (DB) services. A variety of NUCAPS sounding products are also ingested into the Advanced Weather Interactive Processing System (AWIPS-2) for their utility by many Weather Forecasting Offices (WFOs) nationwide.

Following the user groups' recommendations from the NOAA Global Monitoring Laboratory (GML) and Proving Ground and Risk Reduction (PGRR) initiatives, the NUCAPS team implemented the addition of averaging kernels (AKs) into the NUCAPS operational product output files. These data facilitate the comparison of satellite-retrieved profiles with model simulations and in situ observations to identify the relative contributions of the retrieval versus the a priori and assess the vertical sensitivity of the retrieved profiles. In addition, the NUCAPS team performed a wide range of scientific investigations and validation efforts to further improve temperature and water vapor biases in the boundary layer, land snow/ice, and ocean spectral emissivity improvements, ozone product improvements, and surface corrections to alleviate product use for operational applications. Toward new product development, the NUCAPS team performed research and validation efforts to include Ammonia (NH3) as a future operational product. This paper aims to provide details of these upgrades, the utilization of the NUCAPS products for many regional and global applications, and the monitoring of significant environmental events.