The National Oceanic and Atmospheric Administration (NOAA) Unique Combined Atmospheric Processing System (NUCAPS) retrieves atmospheric temperature, water vapor, and trace gases profiles from hyperspectral infrared sounding and microwave instruments aboard Joint Polar Satellite System (JPSS) satellites, and the Infrared Atmospheric Sounder (IASI) aboard the Meteorological Operational Satellite Program (Metop) satellites. Among all enhancement of the recently released NUCAPS V3.1, a new ozone climatology, a new carbon dioxide climatology, and averaging kernel matrix output are important updates. The comparison between NUCAPS retrieved ozone and ECMWF analysis on 12 focus days in 12 months indicates that the global ozone retrievals are improved in all seasons, especially over Antarctic region during spring to summer transition time. The diagnostic study using averaging kernel analysis shows that NUCAPS retrieved ozone profiles have good agreement with ozonesonde measurements.

The NOAA Unique Combined Atmospheric Processing System (NUCAPS) is the official operational hyperspectral enterprise sounding product system that produces vertical profiles of temperature, water vapor, ozone, and various trace gas products (e.g., CO, CH4, and CO2). The NOAA Center for Satellite Applications and Research (STAR) has implemented the NUCAPS enterprise algorithm to produce these atmospheric and trace gas products from the Joint Polar Satellite System (JPSS, NOAA-20, and the JPSS-2 satellite expected to be launched in September 2022) Cross-track Infrared Sounders (CrIS), and from the Infrared Atmospheric Sounder (IASI) instruments aboard the Meteorological Operational Satellite Program (MetOp-B, C, 9:30 AM/PM orbit) series of satellites. In pursuance of the European Organisation for the Exploitation of Meteorological Satellite Second Generation (EUMETSAT-SG, expected launch in September 2022) IASI Next Generation (IASI-NG) hyperspectral observations, NOAA STAR has initiated refinements to the NUCAPS algorithm to produce NOAA unique products from the IASI-NG hyperspectral sounder. This paper presents an overview of the NUCAPS atmospheric composition and trace gas products, performance, and utilization for many regional and global applications. Refinements and augmenting the NUCAPS for EPS-SG IASI, recent improvements to the data products accommodating user needs, upgrades to the data products to support near-real-time applications are discussed. In addition, continued efforts towards reprocessing to generate missionlong high-quality science products and geophysical data products via direct broadcast networks are discussed for user awareness and international collaborations.

A geostationary (GEO) hyperspectral infrared sounder (HyIRS) is capable of providing high spectral (0.625 cm −1 ), temporal (every 30 min) and spatial (4 km) resolution observations over the continental U.S. (CONUS). Frequent observations from a GEO-HyIRS at high spatial resolution are expected to contribute to the generation of three-dimensional structures of atmospheric temperature and humidity, and wind. These new observations will provide valuable information for timely forecasts of severe storms over the CONUS and the overall Western Hemisphere. Infrared (IR) sounder observations from a geostationary orbit open a new set of possibilities, including the capability of monitoring the diurnal cycle of atmospheric patterns, which is difficult from Low Earth Orbit IR sounders and the capability of timely and accurate retrievals of several trace gases. In this article, the feasibility of adding a HyIRS into the next generation of U.S. geostationary environmental satellites is studied. The configuration of a notional U.S. GEO-HyIRS sensor and its ground data processing system are discussed. A hyperspectral IR data simulator is developed and reported as part of this engineering study, where proxy data is used to model the end-to-end ground processing system. Various considerations for the configuration and the calibration and validation of the instrument are addressed.

The NOAA Unique Combined Atmospheric Processing System (NUCAPS) is the official operational hyperspectral enterprise sounding product system that produces vertical profiles of temperature, water vapor, ozone, and a variety of trace gas products (e.g. CO, CH4, and CO2). These products provide continued support of global environmental data from multiple polar-orbiting satellites to monitor atmospheric composition, trace gas concentrations, climate change and Earth system processes. This paper presents an overview of the NUCAPS atmospheric composition products, performance, and utilization for many regional and global applications. Future plans on collaborations, special data needs by user communities, and upgrades to the data products to support near real-time applications are discussed. In addition, continued efforts towards reprocessing to generate mission-long high-quality science products, adapting to enterprise algorithms, and providing calibrated radiances and geophysical data products via direct broadcast networks are discussed for user awareness and international collaborations.

The Outgoing Longwave Radiation (OLR) package was first developed as a stand-alone application, and then integrated into the National Oceanic and Atmospheric Administration (NOAA) Unique Combined Atmospheric Processing System (NUCAPS) hyperspectral sounding retrieval system. An objective of this package is to provide near-real-time OLR products derived from the Cross Track Infrared Sounder (CrIS) onboard the Joint Polar Satellite System (JPSS) satellites. It was initially developed and validated with CrIS onboard the Suomi National Polar-orbiting Partnership (SNPP) satellite, and has been expanded to JPSS-1 (renamed NOAA-20 after launch) datasets that are currently available to the public. In this paper, we provide the results of detailed validation tests with NOAA-20 CrIS for large and wide representative conditions at a global scale. In our validation tests, the observations from Clouds and Earth’s Radiant Energy System (CERES) on Aqua were treated as the absolute reference or “truth”, and those from SNPP CrIS OLR were used as the transfer standard. The tests were performed on a 1°×1° global spatial grid over daily, monthly, and yearly timescales. We find that the CrIS OLR products from NOAA-20 agree exceptionally well with those from Aqua CERES and SNPP CrIS OLR products in all conditions: the daily bias is within ±0.6 Wm−2, and the standard deviation (STD) ranges from 4.88 to 9.1 Wm−2. The bias and the STD of OLR monthly mean are better, within 0.3 and 2.0 Wm−2, respectively. These findings demonstrate the consistency between NOAA-20 and SNPP CrIS OLR up to annual scales, and the robustness of NUCAPS CrIS OLR products.

This paper provides an overview of the validation of National Oceanic and Atmospheric Administration (NOAA) operational retrievals of atmospheric carbon trace gas profiles, specifically carbon monoxide (CO), methane (CH4) and carbon dioxide (CO2), from the NOAA-Unique Combined Atmospheric Processing System (NUCAPS), a NOAA enterprise algorithm that retrieves atmospheric profile environmental data records (EDRs) under global non-precipitating (clear to partly cloudy) conditions. Vertical information about atmospheric trace gases is obtained from the Cross-track Infrared Sounder (CrIS), an infrared Fourier transform spectrometer that measures high resolution Earth radiance spectra from NOAA operational low earth orbit (LEO) satellites, including the Suomi National Polar-orbiting Partnership (SNPP) and follow-on Joint Polar Satellite System (JPSS) series beginning with NOAA-20. The NUCAPS CO, CH4, and CO2 profile EDRs are rigorously validated in this paper using well-established independent truth datasets, namely total column data from ground-based Total Carbon Column Observing Network (TCCON) sites, and in situ vertical profile data obtained from aircraft and balloon platforms via the NASA Atmospheric Tomography (ATom) mission and NOAA AirCore sampler, respectively. Statistical analyses using these datasets demonstrate that the NUCAPS carbon gas profile EDRs generally meet JPSS Level 1 global performance requirements, with the absolute accuracy and precision of CO 5% and 15%, respectively, in layers where CrIS has vertical sensitivity; CH4 and CO2 product accuracies are both found to be within ±1%, with precisions of ≈1.5% and ⪅0.5%, respectively, throughout the tropospheric column.

The NOAA Unique Combined Atmospheric Processing System (NUCAPS) is currently the National Oceanic and Atmospheric Administration (NOAA) operational hyper-spectral infrared sounding product system for deriving vertical profiles of temperature, water vapor, ozone, and trace gas products (CO, CH4, and CO2). In pursuance on the use of European Organisation for the Exploitation of Meteorological Satellite Second Generation (EUMETSAT-SG, expected launch in 2022) IASI Next Generation (IASI-NG) hyperspectral observations, NOAA Center for Satellite Applications and Research (STAR) has initiated refinements to the NUCAPS algorithm to produce NOAA unique products from the IASI-NG and accompanying Microwave Sounder (MWS). This paper presents an overview of the NUCAPS Suomi-NPP/NOAA-20 products performance and on-going efforts in setting up a NUCAPS-NG product development system using proxy/synthetic data sets provided by the EUMETSAT and generated at STAR for the IASI-NG instrument.

This study describes the algorithm for deriving near-real-time outgoing longwave radiation (OLR) from Cross-Track Infrared Sounder (CrIS) hyperspectral infrared sounder radiance measurements. 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. CrIS-derived OLR values are estimated as a weighted linear combination of CrIS-adjusted "pseudochannel'' radiances. The algorithm uses the Atmospheric Infrared Sounder (AIRS) as the transfer instrument, and a least squares regression algorithm is applied to generate two sets of regression coefficients. The first set of regression coefficients is derived from collocated Clouds and the Earth's Radiant Energy System (CERES) OLR on Aqua and pseudochannel radiances calculated fromAIRS radiances. The second set of coefficients is derived to adjust the CrIS pseudochannel radiance to account for the differences in pseudochannel radiances between AIRS and CrIS. The CrIS-derived OLR is then validated by using a limited set of available CERES SNPP OLR observations over 1 degrees x 1 degrees global grids, as well as monthly OLR mean and interannual differences against CERES OLR datasets from SNPP and Aqua. The results show that the bias of global CrIS OLR estimation is within +/- 2W m (-2) and that the standard deviation is within 5 W m (2) for all conditions, and +/- 1 and 3 W m (2) for homogeneous scenes. The interannual CrIS-derivedOLR differences agree well with Aqua CERES interannualOLR differences on a 1 degrees x 1 degrees spatial scale, with only a small drift of the global mean of these two datasets of around 0.004 W m (-2)

The Advanced Technology Microwave Sounders (ATMS), carried on the Suomi National Polar‐orbiting Partnership (SNPP) satellite, was launched on 28 October 2011. The ATMS is a follow‐on instrument to advanced microwave sounding unit (AMSU), currently flying on National Oceanic and Atmospheric Administration (NOAA) satellites. The primary new ATMS features are a reduced hardware package and improved gap coverage. One thing in common about cross‐track sounders is a scan perpendicular to the motion of the satellite, allowing a broad swath of measurements to be taken. But an undesirable feature is that the measurements vary with scan angle because of changes in the optical pathlength through the Earth's atmosphere between the Earth and the satellite. One approach to this problem is to limb adjust the measurements to a fixed view angle. The limb correction algorithm applied to ATMS is based on the heritage methodology originally applied to MSU and later to AMSU. The limb correction method is applied to each of the 96 ATMS field of view (FOV) per scan line, adjusting the off‐nadir FOV to the nadir view with fitting error generally within the instrumental noise. The limb‐adjusted brightness temperature were used in the original, legacy TIROS Operational Vertical Sounder, and Advanced TIROS Operational Vertical Sounder NOAA sounding product algorithms and more recently to derive the total precipitation water (TPW) retrieval over ocean, with a bias of 0.046 mm and a standard deviation of 3.43 mm, when compared with European Centre for Medium‐Range Weather Forecasts TPW data. The limb‐corrected brightness temperature can be used to detect the atmospheric weather features, such as the warm cores for tropical cyclones, and the imagery presents snapshots for quick weather signal diagnosis.

This paper continues an overview of the validation of operational profile retrievals from the Suomi National Polar-Orbiting Partnership (SNPP), with focus here given to the infrared (IR) ozone profile environmental data record (EDR) product. The SNPP IR ozone profile EDR is retrieved using the cross-track IR sounder (CrIS), a Fourier transform spectrometer that measures high-resolution IR earth radiance spectra containing atmospheric state information, namely, vertical profiles of temperature, moisture, and trace gas constituents. The SNPP CrIS serves as the U.S. low earth orbit (LEO) satellite IR sounding system and will be featured on future Joint Polar Satellite System (JPSS) LEO satellites. The operational sounding algorithm is the National Oceanic and Atmospheric Administration-Unique Combined Atmospheric Processing System (NUCAPS), a legacy sounder science team algorithm that retrieves atmospheric profile EDR products, including ozone and carbon trace gases, with optimal vertical resolution under non-precipitating (clear to partly cloudy) conditions. The NUCAPS ozone profile product is assessed in this paper using extensive global in situ truth data sets, namely, ozonesonde observations launched from ground-based networks and from ocean-based intensive field campaigns, along with numerical weather predic-tion model output. Based upon rigorous statistical analyses using these data sets, the NUCAPS ozone profile EDRs are determined to meet the JPSS Level 1 global performance requirements.

This work presents an analysis of the vertical resolution of the temperature and water vapor retrieved by the National Oceanic and Atmospheric Administration (NOAA) Unique Combined Atmospheric Processing System (NUCAPS) using averaging kernels as a diagnostic tool. One of the goals of an atmospheric profile retrieval system is to estimate the state of the atmosphere using an optimal set of observations containing independent information content in order to simultaneously minimize the retrieval error and maximize the vertical resolution. The averaging kernels are also used to compute the number of degrees of freedom of retrieved temperature and water vapor in order to estimate the number of useful independent observations contained in the infrared and microwave observations. Our work uses data obtained from the Suomi National Polar-orbiting Partnership (S-NPP) Cross-track Infrared Sounder (CrIS) and the Advanced Technology Microwave Sounder (ATMS) to diagnose the vertical resolution of NUCAPS retrieved sounding products over different latitudes and seasons, and to support comparisons of retrievals against correlative radiosonde measurements. This work is expected to be extended to other NUCAPS products, since the generation of the averaging kernels is a functionality embedded as part of NUCAPS.

This paper provides an overview of the validation of the operational atmospheric vertical temperature profile (AVTP) and atmospheric vertical moisture profile (AVMP) environmental data record (EDR) products retrieved from the Cross-track Infrared Sounder (CrIS) and the Advanced Technology Microwave Sounder (ATMS), two passive sounding systems onboard the Suomi National Polar-Orbiting Partnership (SNPP) satellite. The CrIS/ATMS suite serves as the U.S. low earth orbit (LEO) satellite sounding system and will span the future Joint Polar Satellite System (JPSS) LEO satellites. The operational sounding algorithm is the National Oceanic and Atmospheric Administration-Unique Combined Atmospheric Processing System (NUCAPS), a legacy sounder science team algorithm capable of retrieving atmospheric profile EDR products with optimal vertical resolution under nonprecipitating (clear to partly cloudy) conditions. The SNPP NUCAPS AVTP and AVMP EDR products are validated using extensive global in situ baseline data sets, namely, radiosonde observations launched from ground-based networks and ocean-based intensive field campaigns, along with numerical weather prediction model output. Based upon statistical analyses using these data sets, the SNPP AVTP and AVMP EDRs are determined to meet the JPSS Level 1 global performance requirements.

This paper examines the performance of satellite sounder atmospheric vertical moisture profiles under tropospheric conditions encompassing moisture contrasts driven by convection and advection transport mechanisms, specifically Atlantic Ocean Saharan air layers (SALs), tropical Hadley cells, and Pacific Ocean atmospheric rivers (ARs). Operational satellite sounder moisture profile retrievals from the Suomi National Polar-Orbiting Partnership (SNPP) NOAA Unique Combined Atmospheric Processing System (NUCAPS) are empirically assessed using collocated dedicated radiosonde observations (raobs) obtained from ocean-based intensive field campaigns. The raobs from these campaigns provide uniquely independent correlative truth data not assimilated into numerical weather prediction (NWP) models for satellite sounder validation over oceans. Although ocean cases are often considered "easy" by the satellite remote sensing community, these hydro meteorological phenomena present challenges to passive sounders, including vertical gradient discontinuities (e.g., strong inversions), as well as persistent uniform clouds, aerosols, and precipitation. It is found that the operational satellite sounder 100-layer moisture profile NUCAPS product performs close to global uncertainty requirements in the SAL/Hadley cell environment, with biases relative to raob within 10% up to 350 hPa. In the more difficult AR environment, bias relative to raob is found to be within 20% up to 400 hPa. In both environments, the sounder moisture retrievals are comparable to NWP model outputs, and cross-sectional analyses show the capability of the satellite sounder for detecting and resolving these tropospheric moisture features, thereby demonstrating a near-real-time forecast utility over these otherwise raob-sparse regions.

The Cross-track Infrared Sounder (CrIS) and the Advanced Technology Microwave Sounder (ATMS) instruments aboard the Suomi National Polar-orbiting Partnership satellite provide high-quality hyperspectral infrared and microwave observations to retrieve atmospheric vertical temperature and moisture profiles (AVTP and AVMP) and many other environmental data records (EDRs). The official CrIS and ATMS EDR algorithm, together called the Cross-track Infrared and Microwave Sounding Suite (CrIMSS), produces EDR products on an operational basis through the interface data processing segment. The CrIMSS algorithm group is to assess and ensure that operational EDRs meet beta and provisional maturity requirements and are ready for stages 1-3 validations. This paper presents a summary of algorithm optimization efforts, as well as characterization and validation of the AVTP and AVMP products using the European Centre for Medium-Range Weather Forecasts (ECMWF) analysis, the Atmospheric Infrared Sounder (AIRS) retrievals, and conventional and dedicated radiosonde observations. The global root-mean-square (RMS) differences between the CrIMSS products and the ECMWF show that the AVTP is meeting the requirements for layers 30-300hPa (1.53K versus 1.5K) and 300-700hPa (1.28K versus 1.5K). Slightly higher RMS difference for the 700hPa-surface layer (1.78K versus 1.6K) is attributable to land and polar profiles. The AVMP product is within the requirements for 300-600hPa (26.8% versus 35%) and is close in meeting the requirements for 600hPa-surface (25.3% versus 20%). After just one year of maturity, the CrIMSS EDR products are quite comparable to the AIRS heritage algorithm products and show readiness for stages 1-3 validations.

Scope of this paper is a cross-comparison among the AIRS/AMSU, IASI/AMSU/MHS and CrIS/ATMS retrieval results using the NOAA/NESDIS/STAR Operational Hyper Spectral Retrieval Algorithm. We perform a detailed analysis of the statistical and instrument performance of the three systems in order to assess their level of maturity and inter-consistency.