Different retrieval algorithms have been developed to process top-of-atmosphere (TOA) spectral radiance data provided by hyperspectral infrared sounder missions. Those algorithms are either optimal estimation method (OEM) based schemes with radiative transfer calculation involved in the retrieval process, or machine learning based methods that allow ultra-efficient data procession but lack of radiometric consistency validation based on the directly measured information. Combining both approaches leverages their respective technical advantages, leading to more accurate results. This study introduces a hyperspectral sounder fingerprinting algorithm to explore this hybrid approach. This approach involves the use of a spectral information-based classification method to identify an reference geophysical state and the corresponding radiative kernel. This enables the efficient retrieval of geophysical variables of interest through a radiative kernel-based linear inversion procedure. The fingerprinting method has been applied to analyze a decadelong hyperspectral sounder data record.

The Hunga Tonga-Hunga Ha'apai volcanic eruption, with the largest eruption occurring on 15 January 2022, ejected unprecedented amounts of water vapor (H2O) and SO2into the stratosphere. Using the hyperspectral infrared sounder CrIS on S-NPP and JPSS-1 (also NOAA-20), we present some unique features of the spectral near 9.6 μm and its great potential value for detecting plumes or clouds with tops near or above tropopause. We identified the existence of two umbrella clouds and observed the continued westward propagation of the upper plume even 8-9 hours after the eruption onset, as well as its dissipation from two CrIS observations onboard JPSS-1 and S-NPP taken in 50 minutes apart. Using a new Single Field-of-view Sounder Atmospheric Products (SiFSAP) from CrIS and ATMS on JPSS-1, which has a high spatial resolution of about 14 km, this study analyzes the impact of Hunga Tonga eruption on the distribution of temperature, H2O and ozone near the tropopause. These results demonstrate the value of hyperspectral infrared sounder and its single-field-view retrieval products for monitoring the volcanic eruptions and their impact on the lower stratosphere.

The Single Field-of-view Sounder Atmospheric Products (SiFSAP) answer the need for a novel high spatial resolution atmospheric data product for major hyper-spectral infrared (IR) sounder missions. SiFSAP include a complete set of atmospheric vertical profiles, cloud, and surface properties, which are physically retrieved from top-of-atmosphere (TOA) spectral radiances under all-sky conditions via a rigorously defined radiative transfer relationship. By using a state-of-art fast radiative transfer model and a carefully designed optimal estimation based physical retrieval scheme, the SiFSAP algorithm ensures both an ultra-fast data processing speed needed for operational weather applications and the radiometric consistency desired by long-term climate studies. SiFSAP supplement existing operational products by providing data at the native spatial resolution of the sounder instruments, the direct and accurate retrieval of cloud scattering properties, and the establishment of ‘radiance closure’.

The Single Field-of-view Sounder Atmospheric Products (SiFSAP), including ozone (0 3 ) and carbon monoxide (CO), from CrIS on SNPP have a spatial resolution of about 14 km at nadir. Such high-resolution sounder products enable us to make process-oriented analysis of CO emission and transport from large wildfires as well as the 0 3 production along the transport of fire plumes. An analysis of SiFSAP CO from Australia's unprecedented wildfires in the end of 2019 to early 2020, as well as comparison with satellite products from TROPOMI and MOPPIT and MERRA-2 reanalysis products, demonstrate an overall good agreement of CO observations among these space-borne sensors. This study also demonstrates the advantage of the SiFSAP CO in capturing the feature of CO transport and 0 3 production from wildfires, which will benefit air quality study.

The Single Field of View (SFOV) retrieval products from CrIS on SNPP have a spatial resolution of ∼ 0.15 by 0.15 degree. Such high resolution observations of the thermodynamic state of atmosphere may provide a very useful dataset to monitor the extreme weather events and strong dynamic transport process. This study compared the SFOV-retrieved temperature and water vapor with ERA5 reanalysis data for one polar vortex breakup case and one stratospheric intrusion event. The results show a good agreement between them in matching the large scale patterns but with some differences in the finer scale features. Comparison of the corresponding SFOV ozone with OMPS measurements demonstrated that the enhancement of ozone can be used to map the air transport. This study suggests that the SFOV sounding products may have a great value to help analyze the mechanism of dynamics, model diagnosis and weather forecasting.

A physical retrieval system is developed for all sky single field-of-view (FOV) hyperspectral sounding. This system can be used to retrieve atmospheric temperature, moisture, and trace gas profiles, along with cloud height and cloud microphysical properties simultaneously from single FOV radiances measured by hyperspectral sounders. Single FOV retrieval results allow the users to extract horizontal gradient information with a spatial resolution defined by the size of one FOV. Moreover, the system finds solutions by directly fitting observed spectral radiances and therefore can be used to obtain radiative kernels that fulfill the `radiance closure' needed for climate applications. As a comparison, current operational retrieval algorithms find solutions by fitting the `cloud cleared' radiances generated from several adjacent FOVs. Not only the spatial resolution of those results is several times coarser than that defined by a single FOV, but the results cannot be used to build radiometric consistent radiative kernels under cloudy sky conditions. In this paper, some applications of the system are demonstrated to highlight the benefit of the full spatial resolution retrieval and the capability of building radiometric consistent radiative kernels under all sky conditions.

Since launch of the Suomi NPP (SNPP) satellite in late 2011, two airborne field campaigns have been conducted with a primary focus on SNPP instrument and data product calibration / validation: 1) mid-latitude flights based out of Palmdale, CA during May 2013 (SNPP-1), and 2) flights over Greenland during March 2015 while based out of Keflavik, Iceland (SNPP-2). In addition to under-flying SNPP, aircraft flight profiles were defined to also obtain coincident observations with the NASA A-train (i.e. AQUA), MetOP-A, and MetOP-B advanced sounder satellites (i.e. AIRS, IASI, and CrIS), along with radiosonde and ground truth sites. The NASA LaRC National Airborne Sounder Testbed-Interferometer (NAST-I) was one of the key payload sensors aboard the ER-2 aircraft during these campaigns. This presentation summarizes the SNPP field campaigns and shows sample inter-comparisons results involving NAST-I and other measurement assets.

This paper applies a physical inversion approach to retrieve geophysical properties from the single instrumental field-of-view (FOV) spectral radiances measured by the Infrared Atmospheric Sounding Interferometer (IASI) under all-sky conditions. We demonstrate the use of a principal-component-based radiative transfer model (PCRTM) and a physical inversion methodology to simultaneously retrieve cloud radiative and microphysical properties along with atmospheric thermodynamic parameters. By using a fast parameterization scheme, the PCRTM can include the cloud scattering properties simulation in radiative transfer calculations without incurring much more computational cost. The computational speed achieved for a single FOV forward simulation under cloudy skies is similar to that normally achieved for clear skies. The retrieval algorithm introduced herein adopts a novel cloud phase determination scheme, to stabilize and/or constrain retrieval iterations, based on characteristics of the reflectance and transmittance of ice and water clouds. A modified Gaussian-Newton minimization technique is employed in the iterative inversion process in order to overcome a highly nonlinear cost function introduced by the cloud parameters. We carry out a rigorous error analysis for the retrieval of temperature, moisture, ozone (O3), and carbon monoxide (CO) from IASI measurements under cloudy-sky conditions. Our algorithm is applied to real IASI observations. Retrieval results are validated using European Center for Medium-Range Weather Forecasting data and collocated Lidar/Radar measurements, and the dependence of retrieval accuracy on cloud optical depth is illustrated.

As a part of the Joint Polar Satellite System (JPSS) and the Suomi National Polar-orbiting Partnership (NPP), the Cross-track Infrared Sounder (CrIS) and Advanced Technology Microwave Sounder (ATMS) instruments make up the Cross-track Infrared and Microwave Sounder Suite (CrIMSS). CrIMSS primarily provides globally-referenced calibrated radiances and vertical profiles of temperature, moisture, and pressure. The CrIMSS operational code has been ported to various LINUX systems and retrievals are performed using both proxy and real ATMS/CrIS data. The high quality proxy data generated from the IASI instrument provided useful testing for the CrIMSS EDR algorithm prior to the launch of the SUOMI NPP satellite. The experience learned from processing the proxy data helped us to handle the SUOMI NPP CrIS/ATMS data as soon as they became available to the CAL/VAL team. In this paper, encouraging preliminary results of applying the ported CrIMSS EDR algorithm to the SUOMI NPP CrIS/ATMS data are presented.

Ultraspectral resolution infrared (IR) radiances obtained from nadir observations provide information about the atmosphere, surface, aerosols, and clouds. Surface spectral emissivity (SSE) and surface skin temperature from current and future operational satellites can and will reveal critical information about the Earth's ecosystem and land-surface-type properties, which might be utilized as a means of long-term monitoring of the Earth's environment and global climate change. In this study, fast radiative transfer models applied to the atmosphere under all weather conditions are used for atmospheric profile and surface or cloud parameter retrieval from ultraspectral and/or hyperspectral spaceborne IR soundings. An inversion scheme, dealing with cloudy as well as cloud-free radiances observed with ultraspectral IR sounders, has been developed to simultaneously retrieve atmospheric thermodynamic and surface or cloud microphysical parameters. This inversion scheme has been applied to the Infrared Atmospheric Sounding Interferometer (IASI). Rapidly produced SSE is initially evaluated through quality control checks on the retrievals of other impacted surface and atmospheric parameters. Initial validation of retrieved emissivity spectra is conducted with Namib and Kalahari desert laboratory measurements. Seasonal products of global land SSE and surface skin temperature retrieved with IASI are presented to demonstrate seasonal variation of SSE.

As a part of the National Polar-orbiting Operational Environmental Satellite System (NPOESS) and the NPOESS Preparatory Project (NPP), the instruments Cross-track Infrared Sounder (CrIS) and Advanced Technology Microwave Sounder (ATMS) make up the Cross-track Infrared and Microwave Sounder Suite (CrIMSS). CrIMSS will primarily provide global temperature, moisture, and pressure profiles and calibrated radiances [1]. In preparation for the NPOESS/NPP launch, porting and testing of the CrIMSS Environmental Data Record (EDR) algorithms need to be performed.

The geosynchronous-imaging Fourier transform spectrometer (GIFTS) engineering demonstration unit (EDU) is an imaging infrared spectrometer designed for atmospheric soundings. It measures the infrared spectrum in two spectral bands (14.6 to 8.8 mum, 6.0 to 4.4 mum) using two 128times128 detector arrays with a spectral resolution of 0.57 cm-1with a scan duration of ~11 seconds. From a geosynchronous orbit, the instrument will have the capability of taking successive measurements of such data to scan desired regions of the globe, from which atmospheric status, cloud parameters, wind field profiles, and other derived products can be retrieved. The GIFTS EDU provides a flexible and accurate testbed for the new challenges of the emerging hyperspectral era. The EDU ground-based measurement experiment, held in Logan, Utah during September 2006, demonstrated its extensive capabilities and potential for geosynchronous and other applications (e.g., earth observing environmental measurements). This paper addresses the experiment objectives and overall performance of the sensor system with a focus on the GIFTS EDU imaging capability and proof of the GIFTS measurement concept.

The National Polar-orbiting Operational Environmental Satellite System (NPOESS) is expected to become the central element of the long-term global observing system. While the critical design and fabrication for many sensor suites have been completed, some aspects of the instrument configuration of NPOESS's primary infrared sensor, the Cross-track Infrared Sounder (CrIS), can still be optimized. This paper considers the relationship between various specifications for the sensor spatial resolution (sampling area size) and the anticipated performance of global temperature and water vapor profile sounding, these being among the highest priority measurements NPOESS will provide. Although the trade-off between signal to noise ratio, dwell time, sampling area (SA), and other instrumental issues such as weight, power and volume are complicated and need to be carefully considered, a finer SA will theoretically enable improved sounding through scattered clouds. Preliminary analysis of high-spectral infrared measurements from Atmospheric InfRared Sounder (AIRS) (which has a 13.5 km nadir SA) on NASA's polar-orbiting EOS-Aqua satellite shows that the percentage of its SA being cloud free is less than 20%. In addition, we demonstrate using sounding and imaging data from NPOESS' surrogate, AIRS and MODIS, how improved SA can achieve not only the improved sounding performance for meeting threshold and objective requirements, but also reduce processing demands, simplify data assimilation and utilization, and enhance delineation of mesoscale moisture gradients.

The methodology for retrieval of atmospheric temperature and composition profiles, and surface thermal properties from observed radiance spectra is reported. These retrieval parameters are determined using a three-stage approach that combines three algorithms: (1) statistical physical-eigenvector-regression, (2) simultaneous non-linear matrix inversion, and (3) trace species profile enhancement. NAST-I aboard a high altitude aircraft has been successfully collecting data during many field campaigns. NAST-I provides relatively high spectral resolution (0.25 cm/sup -1/) measurements in the spectral region of 645-2700 cm/sup -1/ with moderate spatial resolution (a linear resolution equal to 13% of the aircraft altitude at nadir) and cross track scanning (producing a swath width on the Earth's surface of approximately twice the aircraft altitude). Retrieval results from several NAST-I field campaigns are presented in conjunction with co-incident ground and in situ measurements for validation. These results demonstrate the ability of the NAST interferometer to reveal fine-scale horizontal features with relatively high vertical resolution.