Large wildfires and their induced thunderstorms, pyrocumulonimbus (pyroCb), are getting increasing interest and attention. Most previous studies are based on broadband satellite data, and the use of hyperspectral infrared data for pyroCb detection has not been explored. Australia’s unprecedented fires at the end of 2019 to early 2020 induced an extreme pyroCb outbreak, and the largest event occurred on 30 December 2019 was successfully captured by the Cross-track Infrared Sounder (CrIS) onboard JPSS-1 and S-NPP. Analysis of these CrIS data demonstrated that the slopes and standard deviations of the spectral brightness temperature (BT), derived from a linear fitting to the spectrum in 800-980 cm-1, along with the split-window technique using selected CrIS channels, can aid in pyroCb detection. An inverted “V” feature in the spectra near 9.6 μm is associated with high pyroCb, and its depth, H_index, can provide information of cloud top height. These characteristics are verified through radiative transfer model (RTM) simulations and analysis of another case of pyroCb induced from California Creek fire on 5 September 2020. It is found that a combination of H_index and BT difference between 1231 and 677 cm-1is promising to distinguish high pyroCbs. A more accurate determination of pyroCb plume height can be achieved from the single Field of View Sounder Atmospheric Products (SiFSAP), which indicate that several pyroCb pixels reach 3-6 km above the tropopause. These approaches could be applied to study more pyroCbs using over 20 years of hyperspectral sounder data.

NASA’s Climate Absolute Radiance and Refractivity Observatory (CLARREO) Pathfinder (CPF) mission will deploy an Earth-observing reflected solar (RS) spectrometer, designed to measure Earth-reflected solar radiation from the International Space Station with a remarkable SI-traceable radiometric uncertainty of 0.3%-0.6% (k=1). The high-accuracy CPF measurements will provide an on-orbit reference for intercalibrating other spaceflight RS instruments. The CPF intercalibration team will showcase an innovative on-orbit intercalibration approach, wherein two other RS sensors—the shortwave (SW) channel of the Clouds and the Earth’s Radiant Energy System (CERES) and the Reflective Solar Bands (RSB) of the Visible Infrared Imager Radiometer Suite (VIIRS)—are intercalibrated against CPF benchmark measurements, with an unprecedented intercalibration methodology uncertainty of 0.3% (k=1).

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.

A novel ice particle optical property model, referred to as the Lidar Ice Model (LIM), is developed for applications to active remote sensing in three channels centered at 355, 532, and 1064 nm. The theoretical lidar ratio and integrated attenuated backscatter (IAB) computed based on the LIM are consistent with the Cloud-Aerosol Lidar and Infrared Pathfinder in Space Observations (CALIPSO) counterparts due to a better treatment of backscattering properties in the present study. The LIM provides robust optical properties to facilitate the implementation of active remote sensing algorithms for inferring the microphysical and radiative properties of ice clouds.

The Climate Absolute Radiance and Refractivity (CLARREO) Pathfinder (CPF) mission will take Système Internationale (SI)-traceable spectral reflectance measurements of Earth at an unprecedented accuracy of 0.3% (k=1). CPF will also take measurements to support intercalibration of other satellite-based sensors. To achieve the desired intercalibration methodology uncertainty of 0.3% (k=1), the CPF intercalibration measurements need to closely match those from target sensors in time, space, angles, and wavelength. This paper introduces an innovative angular correction method to significantly reduce errors due to angular mismatches between CPF and target sensor measurements. The method leverages the spectral correlations among the reflected solar radiances from the same surface target at two adjacent angles. Our studies have shown that the spectral radiance or reflectance difference measured at angles slightly deviating from the CPF observation angles can be accurately predicted based on the hyperspectral CPF measurements. The method will serve as part of the operational algorithms to support the core mission goal of conducting intercalibration analysis with measurements from the shortwave channel of the Clouds and the Earth’s Radiance Energy System (CERES) and the reflective solar bands of the Visible Infrared Imaging Radiometer Suite (VIIRS); however, it can also be extended for other reference-target intercalibration applications.

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.

The Climate Absolute Radiance and Refractivity Observatory (CLARREO) Pathfinder (CPF) mission consists of a high accuracy reflected solar spectrometer that will take measurements from the International Space Station for one year starting in 2023. CPF will demonstrate that its novel on-orbit absolute calibration approaches are capable of achieving 0.3% (1-sigma) radiometric uncertainty. Additionally, using its two-axis pointing gimbal which enables nearly-concurrent measurements matching look angles with other orbiting sensors, CPF will demonstrate a novel inter-calibration approach by inter-calibrating CERES and VIIRS. CPF is currently in its Final Design and Fabrication Stage and recently passed its Critical Design Review.

CLARREO Pathfinder is a hyperspectral instrument designed to resolve reflectance of solar radiation from Earth in the wavelength range of 350 nm to 2300 nm with an uncertainty of 0.3% ( k=2) or less. Its success will demonstrate CLARREO's ability to provide on-orbit SI-Traceable calibration of measured spectral reflectance with an advanced accuracy. The CLARREO pathfinder simulator has been developed to generate high-fidelity inter-calibration event data products that can be used for pre-launch inter-calibration algorithm study. A high-fidelity simulation for CLARREO inter-calibration events includes computationally intensive radiative transfer calculations for observations within each individual collocation footprint. A principal component based radiative transfer model is incorporated in the simulator to enable an ultra-fast forward simulation, ensuring a low-latency data processing for month-to year-long intercalibration events. This paper introduces the design and development of the CLARREO pathfinder simulator and some of its applications for inter-calibration matching error evaluation.

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.

NUCAPS (NOAA Unique CrIS/ATMS Processing System) uses the same scientific foundation as AIRS team science algorithm. The NUCAPS is being run operationally at NOAA for Suomi-NPP CrIS/ATMS, Metop-A/B IASI/AMSUA/MHS and provides atmospheric profiles of temperature, moisture, ozone, carbon oxide, carbon monoxide, and Methane. The sounding team at NASA developed a retrieval system using principal component radiative transfer model (PCRTM). The NASA retrieval system can be applied under all weather conditions at single field of view (FOV). In this presentation, we will present the trace gaseous environmental data record from hyperspectral sounders.

Atmospheric Vertical Temperature Profile (AVTP) and Atmospheric Vertical Moisture Profile (AVMP) retrievals produced by the Cross-track Infrared Sounder and the Advanced Technology Microwave Sounder suite (CrIMSS) official algorithm were evaluated with global European Center for Medium Range Weather Forecast (ECMWF) analysis fields, radiosonde (RAOB) measurements, and Aqua-Atmospheric Infrared Sounder (AIRS) heritage algorithm retrievals. The operational CrIMSS AVTP and AVMP product statistics with truth data sets are quite comparable to the AIRS heritage algorithm statistics. Planned updates and improvements to the CrIMSS algorithm will alleviate many issues observed with `day-one' focus-day results and show promise in meeting the Key Performance Parameter (KPP) specifications.

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.

This paper reports on the recent status of the validation program for the Suomi National Polar-orbiting Partnership (NPP) Cross-track Infrared Microwave Sounding Suite (CrIMSS), a hyperspectral infrared sounding system designed for providing high resolution atmospheric vertical temperature and moisture profile (AVTP and AVMP) environmental data records (EDRs). CrIMSS EDR validation activities, currently (as of this writing, May 2012) segueing from the Early-Orbit Checkout (EOC) phase to the Intensive Cal/Val (ICV) phase of the program, are briefly highlighted.

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.