The Experts below are selected from a list of 924 Experts worldwide ranked by ideXlab platform

Robert O Knuteson - One of the best experts on this subject based on the ideXlab platform.

  • A Longwave Broadband QME Based on ARM Pyrgeometer and AERI Measurements
    2020
    Co-Authors: Shepard A. Clough, H E Revercomb, David D Turner, Eli J. Mlawer, David C. Tobin, A. D. Brown, Constantin Andronache, T. R. Shippert, Robert O Knuteson
    Abstract:

    Accurate modeling of the downwelling longwave flux at the surface is critical to our understanding of a number of important issues: the earth’s energy balance; processes at the atmosphere’s lower boundary including ice melt and ocean forcing; and evaluating our ability to model atmospheric fluxes for dynamical models including numerical weather prediction and climate models. Under the Atmospheric Radiation Measurement (ARM) Program, there has been a concerted effort (Brown et al. 1998) to evaluate the modeling of the downwelling zenith spectral Radiances using Atmospheric Emitted Radiance Interferometer (AERI) measurements (Revercomb et al. 1997) and the line-by-line radiative transfer model (LBLRTM) (Clough and Iacono 1995). Up to this point, there has not been a comparable effort to extend this type of analysis to the downwelling fluxes at the surface, which are of interest to the broader community.

  • AERIs for ARM: Accuracy and Applications
    2020
    Co-Authors: Robert O Knuteson, Ray K Garcia, Henry E Revercomb, Wayne F Feltz, R G Dedecker, T P Dirkx, H B Howell, Daniel H. Deslover, David C. Tobin
    Abstract:

    Measurements from the atmospheric Emitted Radiance interferometer (AERI) are used within the Atmospheric Radiation Measurement (ARM) Program to improve our understanding of the atmospheric processes important for atmospheric radiation. One of the earliest ARM goals was the collection of high spectral resolution emission data for validation of radiative transfer model (RTM) calculations in the infrared (IR). Over the years, the list of applications of AERI data have grown to include remote sensing of atmospheric thermodynamic variables, atmospheric constituents, and surface properties. Fundamental to the success of these applications is the radiometric accuracy of the AERI IR atmospheric emission measurements. This paper presents the theoretical accuracy estimates of the AERI measurements and demonstrated performance derived from data collected in the laboratory and in the field.

  • a new marine atmospheric Emitted Radiance interferometer for shipboard atmospheric and oceanic observations
    Fourier Transform Spectroscopy and Hyperspectral Imaging and Sounding of the Environment (2015) paper JM1A.2, 2015
    Co-Authors: Jonathan P Gero, Robert O Knuteson, Denny Hackel, Fred A Best, Ray K Garcia, C Phillips, Henry E Revercomb, William L Smith, Eric Verret, Stephane Lantagne
    Abstract:

    The Marine-Atmospheric Emitted Radiance Interferometer (M-AERI) is a robust, accurate seagoing instrument that measures thermal emission spectra from the sea surface and marine atmosphere. Results from the first shipboard deployment of a new M-AERI instrument are presented.

  • E-AERI calibration performance certification
    Multispectral Hyperspectral and Ultraspectral Remote Sensing Technology Techniques and Applications III, 2010
    Co-Authors: Robert O Knuteson, Denny Hackel, Fred A Best, Henry E Revercomb, Joe K. Taylor, Ray K. Garcia, Nicholas Ciganovich, David D Turner
    Abstract:

    The University of Wisconsin-Madison Space Science and Engineering Center (UW-SSEC) is certifying the calibration performance of a new generation of instruments for the measurement of the downwelling atmospheric infrared spectrum at the surface. The E-AERI instrument series is the commercial follow-on to the successful Atmospheric Emitted Radiance Interferometer (AERI) which was developed at UW-SSEC in the early 1990s with support from the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) program. This paper describes the E-AERI instrument specification, the UW-SSEC certification methodology, and examples of preliminary of results obtained to date. The E-AERI instrument is a commercially available product of ABB/Bomem of Quebec, Canada using technology licensed by the UW-SSEC. The E-AERI meets the same specification as the original AERI instrument in a fully automated system for use in both research and operational profiling networks.

  • Retrieving Temperature and Moisture Profiles from AERI Radiance Observations: AERIPROF Value-Added Product Technical Description Revision 1
    2007
    Co-Authors: Wayne F Feltz, Robert O Knuteson, William L Smith, H B Howell, Harold M Woolf, David D Turner, Jennifer M. Comstock, R Mahon, Chitra Sivaraman, Td Halter
    Abstract:

    This document explains the procedure to retrieve temperature and moisture profiles from high-spectral resolution infrared Radiance data measured by the U.S. Department Of Energy (DOE) Atmospheric Radiation (ARM) Program’s atmospheric Emitted Radiance interferometer (AERI) instrument. The technique has been named the AERIPROF thermodynamic retrieval algorithm. The software has been developed over the last decade at the University of Wisconsin-Madison and has matured into an ARM Value-Added Procedure. This document will describe the AERIPROF retrieval procedure, outline the algorithm routines, discuss the software heritage, and, finally, provide references with further documentation.

Wayne F Feltz - One of the best experts on this subject based on the ideXlab platform.

  • AERIs for ARM: Accuracy and Applications
    2020
    Co-Authors: Robert O Knuteson, Ray K Garcia, Henry E Revercomb, Wayne F Feltz, R G Dedecker, T P Dirkx, H B Howell, Daniel H. Deslover, David C. Tobin
    Abstract:

    Measurements from the atmospheric Emitted Radiance interferometer (AERI) are used within the Atmospheric Radiation Measurement (ARM) Program to improve our understanding of the atmospheric processes important for atmospheric radiation. One of the earliest ARM goals was the collection of high spectral resolution emission data for validation of radiative transfer model (RTM) calculations in the infrared (IR). Over the years, the list of applications of AERI data have grown to include remote sensing of atmospheric thermodynamic variables, atmospheric constituents, and surface properties. Fundamental to the success of these applications is the radiometric accuracy of the AERI IR atmospheric emission measurements. This paper presents the theoretical accuracy estimates of the AERI measurements and demonstrated performance derived from data collected in the laboratory and in the field.

  • Retrieving Temperature and Moisture Profiles from AERI Radiance Observations: AERIPROF Value-Added Product Technical Description Revision 1
    2007
    Co-Authors: Wayne F Feltz, Robert O Knuteson, William L Smith, H B Howell, Harold M Woolf, David D Turner, Jennifer M. Comstock, R Mahon, Chitra Sivaraman, Td Halter
    Abstract:

    This document explains the procedure to retrieve temperature and moisture profiles from high-spectral resolution infrared Radiance data measured by the U.S. Department Of Energy (DOE) Atmospheric Radiation (ARM) Program’s atmospheric Emitted Radiance interferometer (AERI) instrument. The technique has been named the AERIPROF thermodynamic retrieval algorithm. The software has been developed over the last decade at the University of Wisconsin-Madison and has matured into an ARM Value-Added Procedure. This document will describe the AERIPROF retrieval procedure, outline the algorithm routines, discuss the software heritage, and, finally, provide references with further documentation.

  • profiling the lower troposphere over the ocean with infrared hyperspectral measurements of the marine atmosphere Emitted Radiance interferometer
    Journal of Atmospheric and Oceanic Technology, 2007
    Co-Authors: Malgorzata Szczodrak, Peter J Minnett, Nicholas R Nalli, Wayne F Feltz
    Abstract:

    Abstract Measurements of the spectra of infrared emission from the atmosphere were taken by a Marine-Atmospheric Emitted Radiance Interferometer (M-AERI) deployed on the NOAA ship Ronald H. Brown during the Aerosol and Ocean Science Expedition (AEROSE) in the tropical Atlantic Ocean from 29 February to 26 March 2004. The spectra are used to retrieve profiles of temperature and humidity in the lower troposphere up to a height of 3000 m. The M-AERI retrievals of the atmospheric structure require an initial guess profile. In this work, retrievals obtained from four separate initializations are compared, using 1) radiosondes launched from the Ronald H. Brown, 2) NOAA/NWS/NCEP model reanalyses, 3) ECMWF model analyses, and 4) ECMWF model forecasts. The performance of the M-AERI retrievals for all four first-guess sources is then evaluated against the radiosonde measurements. The M-AERI retrievals initialized using radiosondes reproduce the radiosonde profiles quite well and capture much of the observed vertica...

  • continuation of data analysis software development for the atmospheric Emitted Radiance inter ferometer aeri
    2005
    Co-Authors: Robert O Knuteson, Wayne F Feltz, S A Clough
    Abstract:

    Data from the Atmospheric Emitted Radiance Interferometer (AERI) has been analyzed under the ARM Fourier Transform Data Analysis Tools science team project. A portion of the effort was accomplished through a subcontract to S. A. Clough of Atmospheric Environmental Research (AER), Inc. This section of the proposal highlights a few important accomplishments obtained during the past grant period. Specific accomplishments include: 1) The AERIplus temperature and moisture retrieval algorithm (Feltz et al. 2003, 2005) has now implemented a new fast model based upon LBLRTM. The fast model provides a doubling of vertical resolution within the first 100 hPa of atmosphere (surface to 900 hPa) from 10 hPa spacing to 5 hPa. This algorithm has been implemented at Pacific Northwest National Laboratories to upgrade previous AERI retrieval software. A peer reviewed paper has been published with regard to this work along with Value Added Product (VAP) technical document available through ARM web site. 2) Developed an objective methodology to detect planetary boundary layer (PBL) height using the AERI derived potential temperature field. AERI temperature and moisture data are also used to correlate the perturbation temperature and moisture in time within the planetary boundary layer (PBL) to view the structure of PBLmore » turbulence and convection. 3) The temporal resolution of the DOE ARM AERI systems is now being increased to less than 20 seconds (currently ~ 8 minutes depending on system). The University of Wisconsin mobile AERI system was deployed three times (Texas 2002 at SGP, CRYSTAL-FACE in southern Florida, and AWEX 2003 at SGP) collecting data at 40 second temporal resolution. The DOE ARM science team has requested that all DOE ARM AERI systems be upgraded to run in rapid sampling mode (including the ARM Mobile Facility AERI) to provide improved sampling of changing cloud characteristics using high spectral resolution infrared data. This grant has facilitated in the demonstration of improved science when the AERI systems on operated in this higher temporal resolution mode.« less

  • atmospheric Emitted Radiance interferometer part ii instrument performance
    Journal of Atmospheric and Oceanic Technology, 2004
    Co-Authors: Robert O Knuteson, Fred A Best, Ray K Garcia, Henry E Revercomb, Wayne F Feltz, N C Ciganovich, R G Dedecker, T P Dirkx, S C Ellington, H B Howell
    Abstract:

    The Atmospheric Emitted Radiance Interferometer (AERI) instrument was developed for the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Program by the University of Wisconsin Space Science and Engineering Center (UW-SSEC). The infrared emission spectra measured by the instrument have the sensitivity and absolute accuracy needed for atmospheric remote sensing and climate studies. The instrument design is described in a companion paper. This paper describes in detail the measured performance characteristics of the AERI instruments built for the ARM Program. In particular, the AERI systems achieve an absolute radiometric calibration of better than 1% (3s) of ambient Radiance, with a reproducibility of better than 0.2%. The knowledge of the AERI spectral calibration is better than 1.5 ppm (1s) in the wavenumber range 400‐ 3000 cm21.

Henry E Revercomb - One of the best experts on this subject based on the ideXlab platform.

  • AERIs for ARM: Accuracy and Applications
    2020
    Co-Authors: Robert O Knuteson, Ray K Garcia, Henry E Revercomb, Wayne F Feltz, R G Dedecker, T P Dirkx, H B Howell, Daniel H. Deslover, David C. Tobin
    Abstract:

    Measurements from the atmospheric Emitted Radiance interferometer (AERI) are used within the Atmospheric Radiation Measurement (ARM) Program to improve our understanding of the atmospheric processes important for atmospheric radiation. One of the earliest ARM goals was the collection of high spectral resolution emission data for validation of radiative transfer model (RTM) calculations in the infrared (IR). Over the years, the list of applications of AERI data have grown to include remote sensing of atmospheric thermodynamic variables, atmospheric constituents, and surface properties. Fundamental to the success of these applications is the radiometric accuracy of the AERI IR atmospheric emission measurements. This paper presents the theoretical accuracy estimates of the AERI measurements and demonstrated performance derived from data collected in the laboratory and in the field.

  • a new marine atmospheric Emitted Radiance interferometer for shipboard atmospheric and oceanic observations
    Fourier Transform Spectroscopy and Hyperspectral Imaging and Sounding of the Environment (2015) paper JM1A.2, 2015
    Co-Authors: Jonathan P Gero, Robert O Knuteson, Denny Hackel, Fred A Best, Ray K Garcia, C Phillips, Henry E Revercomb, William L Smith, Eric Verret, Stephane Lantagne
    Abstract:

    The Marine-Atmospheric Emitted Radiance Interferometer (M-AERI) is a robust, accurate seagoing instrument that measures thermal emission spectra from the sea surface and marine atmosphere. Results from the first shipboard deployment of a new M-AERI instrument are presented.

  • E-AERI calibration performance certification
    Multispectral Hyperspectral and Ultraspectral Remote Sensing Technology Techniques and Applications III, 2010
    Co-Authors: Robert O Knuteson, Denny Hackel, Fred A Best, Henry E Revercomb, Joe K. Taylor, Ray K. Garcia, Nicholas Ciganovich, David D Turner
    Abstract:

    The University of Wisconsin-Madison Space Science and Engineering Center (UW-SSEC) is certifying the calibration performance of a new generation of instruments for the measurement of the downwelling atmospheric infrared spectrum at the surface. The E-AERI instrument series is the commercial follow-on to the successful Atmospheric Emitted Radiance Interferometer (AERI) which was developed at UW-SSEC in the early 1990s with support from the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) program. This paper describes the E-AERI instrument specification, the UW-SSEC certification methodology, and examples of preliminary of results obtained to date. The E-AERI instrument is a commercially available product of ABB/Bomem of Quebec, Canada using technology licensed by the UW-SSEC. The E-AERI meets the same specification as the original AERI instrument in a fully automated system for use in both research and operational profiling networks.

  • GIFTS Radiance Validation from Ground-Based Sky-Viewing Comparisons to AERI
    Fourier Transform Spectroscopy Hyperspectral Imaging and Sounding of the Environment, 2007
    Co-Authors: Henry E Revercomb, Robert O Knuteson, Fred A Best, William L Smith, David D Turner, David C. Tobin, Joe K. Taylor, Daniel K. Zhou, Robert A. Reisse, Gregory W. Cantwell
    Abstract:

    Spectral Radiance validation of the Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) engineering design unit has been performed using zenith sky viewing comparisons with an Atmospheric Emitted Radiance Interferometer (AERI). Good agreement is demonstrated.

  • noise reduction of atmospheric Emitted Radiance interferometer aeri observations using principal component analysis
    Journal of Atmospheric and Oceanic Technology, 2006
    Co-Authors: David D Turner, Henry E Revercomb, R G Dedecker
    Abstract:

    A principal component noise filter has been applied to ground-based high-spectral-resolution infrared Radiance observations collected by the Atmospheric Emitted Radiance Interferometers (AERIs) deployed by the Atmospheric Radiation Measurement (ARM) program. The technique decomposes the Radiance observations into their principal components, selects the ones that describe the most variance in the data, and reconstructs the data from these components. An empirical function developed for chemical analysis is utilized to determine the number of principal components to be used in the reconstruction of the data. Statistical analysis of the noise-filtered minus original Radiance data, as well as side-by-side analysis of data from two AERI systems utilizing different temporal sampling, demonstrates the ability of the noise filter using this empirical function to retain most of the atmospheric signal above the AERI noise level in the filtered data. The noise filter is applied to data collected at ARM’s tropical, midlatitude, and Arctic sites, demonstrating that the random variability in the data is reduced by 5% to over 450%, depending on the spectral element and location of the instrument. A seasonal analysis of the number of principal components required by the noise filter for each site shows a strong seasonal dependence in the atmospheric variability at the Arctic and midlatitude sites but not at the tropical site.

William L Smith - One of the best experts on this subject based on the ideXlab platform.

  • a new marine atmospheric Emitted Radiance interferometer for shipboard atmospheric and oceanic observations
    Fourier Transform Spectroscopy and Hyperspectral Imaging and Sounding of the Environment (2015) paper JM1A.2, 2015
    Co-Authors: Jonathan P Gero, Robert O Knuteson, Denny Hackel, Fred A Best, Ray K Garcia, C Phillips, Henry E Revercomb, William L Smith, Eric Verret, Stephane Lantagne
    Abstract:

    The Marine-Atmospheric Emitted Radiance Interferometer (M-AERI) is a robust, accurate seagoing instrument that measures thermal emission spectra from the sea surface and marine atmosphere. Results from the first shipboard deployment of a new M-AERI instrument are presented.

  • Retrieving Temperature and Moisture Profiles from AERI Radiance Observations: AERIPROF Value-Added Product Technical Description Revision 1
    2007
    Co-Authors: Wayne F Feltz, Robert O Knuteson, William L Smith, H B Howell, Harold M Woolf, David D Turner, Jennifer M. Comstock, R Mahon, Chitra Sivaraman, Td Halter
    Abstract:

    This document explains the procedure to retrieve temperature and moisture profiles from high-spectral resolution infrared Radiance data measured by the U.S. Department Of Energy (DOE) Atmospheric Radiation (ARM) Program’s atmospheric Emitted Radiance interferometer (AERI) instrument. The technique has been named the AERIPROF thermodynamic retrieval algorithm. The software has been developed over the last decade at the University of Wisconsin-Madison and has matured into an ARM Value-Added Procedure. This document will describe the AERIPROF retrieval procedure, outline the algorithm routines, discuss the software heritage, and, finally, provide references with further documentation.

  • GIFTS Radiance Validation from Ground-Based Sky-Viewing Comparisons to AERI
    Fourier Transform Spectroscopy Hyperspectral Imaging and Sounding of the Environment, 2007
    Co-Authors: Henry E Revercomb, Robert O Knuteson, Fred A Best, William L Smith, David D Turner, David C. Tobin, Joe K. Taylor, Daniel K. Zhou, Robert A. Reisse, Gregory W. Cantwell
    Abstract:

    Spectral Radiance validation of the Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) engineering design unit has been performed using zenith sky viewing comparisons with an Atmospheric Emitted Radiance Interferometer (AERI). Good agreement is demonstrated.

  • near continuous profiling of temperature moisture and atmospheric stability using the atmospheric Emitted Radiance interferometer aeri
    Journal of Applied Meteorology, 2003
    Co-Authors: Wayne F Feltz, Robert O Knuteson, William L Smith, H B Howell, Harold M Woolf, Henry E Revercomb
    Abstract:

    Abstract The Department of Energy Atmospheric Radiation Measurement Program (ARM) has funded the development and installation of five ground-based atmospheric Emitted Radiance interferometer (AERI) systems at the Southern Great Plains (SGP) site. The purpose of this paper is to provide an overview of the AERI instrument, improvement of the AERI temperature and moisture retrieval technique, new profiling utility, and validation of high-temporal-resolution AERI-derived stability indices important for convective nowcasting. AERI systems have been built at the University of Wisconsin—Madison, Madison, Wisconsin, and deployed in the Oklahoma–Kansas area collocated with National Oceanic and Atmospheric Administration 404-MHz wind profilers at Lamont, Vici, Purcell, and Morris, Oklahoma, and Hillsboro, Kansas. The AERI systems produce absolutely calibrated atmospheric infrared Emitted Radiances at one-wavenumber resolution from 3 to 20 μm at less than 10-min temporal resolution. The instruments are robust, are a...

  • Ground-based measurement of cirrus cloud optical properties as validation to aircraft- and satellite-based cloud studies
    Remote Sensing of Clouds and the Atmosphere VII, 2003
    Co-Authors: Daniel H. Deslover, David D Turner, David N. Whiteman, William L Smith
    Abstract:

    Ground-based Atmospheric Emitted Radiance Interferometer (AERI) and Raman Lidar measurements are used to infer cirrus cloud absorption optical depth and effective particle size. Our methodology will be discussed, and results shown for a number of contrasting cloud cases. The high spectral resolution AERI measurements allow inversion of the infrared radiative transfer equation between gaseous absorption lines (e.g., regions of minimal atmospheric emission), referred to as microwindows, to derive the cloud infrared absorption optical depth. Spectral variation in the cloud optical depth yields information on particle size and shape. A best fit of absorption optical depth to the measured absorption optical depth in each microwindow is used to determine the effective radius of particles within the cloud. Results will also be compared to simultaneous upwelling aircraft measurements.

David D Turner - One of the best experts on this subject based on the ideXlab platform.

  • A Longwave Broadband QME Based on ARM Pyrgeometer and AERI Measurements
    2020
    Co-Authors: Shepard A. Clough, H E Revercomb, David D Turner, Eli J. Mlawer, David C. Tobin, A. D. Brown, Constantin Andronache, T. R. Shippert, Robert O Knuteson
    Abstract:

    Accurate modeling of the downwelling longwave flux at the surface is critical to our understanding of a number of important issues: the earth’s energy balance; processes at the atmosphere’s lower boundary including ice melt and ocean forcing; and evaluating our ability to model atmospheric fluxes for dynamical models including numerical weather prediction and climate models. Under the Atmospheric Radiation Measurement (ARM) Program, there has been a concerted effort (Brown et al. 1998) to evaluate the modeling of the downwelling zenith spectral Radiances using Atmospheric Emitted Radiance Interferometer (AERI) measurements (Revercomb et al. 1997) and the line-by-line radiative transfer model (LBLRTM) (Clough and Iacono 1995). Up to this point, there has not been a comparable effort to extend this type of analysis to the downwelling fluxes at the surface, which are of interest to the broader community.

  • Impacts of Targeted AERI and Doppler Lidar Wind Retrievals on Short-Term Forecasts of the Initiation and Early Evolution of Thunderstorms
    Monthly Weather Review, 2019
    Co-Authors: Michael C. Coniglio, David D Turner, Glen S. Romine, Ryan D. Torn
    Abstract:

    AbstractThe ability of Atmospheric Emitted Radiance Interferometer (AERI) and Doppler lidar (DL) wind profile observations to impact short-term forecasts of convection is explored by assimilating r...

  • Recent Advances in AERI Data Processing: Real-time Quality Control and Real-time Thermodynamic Retrievals
    Light Energy and the Environment 2018 (E2 FTS HISE SOLAR SSL), 2018
    Co-Authors: P. Jonathan Gero, Denny Hackel, Ray K Garcia, C Phillips, David D Turner, Alex Diebold, Matthew H. Westphall
    Abstract:

    The Atmospheric Emitted Radiance Interferometer (AERI) measures downwelling thermal infrared Radiance from the atmosphere. Recent development of real-time quality control and thermodynamic retrievals transform the AERI into a vastly more valuable tool for atmospheric science.

  • quantifying the accuracy and uncertainty of diurnal thermodynamic profiles and convection indices derived from the atmospheric Emitted Radiance interferometer
    Journal of Applied Meteorology and Climatology, 2017
    Co-Authors: W G Blumberg, David D Turner, Timothy J Wagner, J Correia
    Abstract:

    AbstractWhile radiosondes have provided atmospheric scientists an accurate high-vertical-resolution profile of the troposphere for decades, they are unable to provide high-temporal-resolution observations without significant recurring expenses. Remote sensing technology, however, has the ability to monitor the evolution of the atmosphere in unprecedented detail. One particularly promising tool is the Atmospheric Emitted Radiance Interferometer (AERI), a passive ground-based infrared radiometer. Through a physical retrieval, the AERI can retrieve the vertical profile of temperature and humidity at a temporal resolution on the order of minutes. The synthesis of these two instruments may provide an improved diagnosis of the processes occurring in the atmosphere. This study provides a better understanding of the capabilities of the AERI in environments supportive of deep, moist convection. Using 3-hourly radiosonde launches and thermodynamic profiles retrieved from collocated AERIs, this study evaluates the a...

  • information content and uncertainties in thermodynamic profiles and liquid cloud properties retrieved from the ground based atmospheric Emitted Radiance interferometer aeri
    Journal of Applied Meteorology and Climatology, 2014
    Co-Authors: David D Turner, Ulrich Lohnert
    Abstract:

    AbstractThe Atmospheric Emitted Radiance Interferometer (AERI) observes spectrally resolved downwelling Radiance Emitted by the atmosphere in the infrared portion of the electromagnetic spectrum. Profiles of temperature and water vapor, and cloud liquid water path and effective radius for a single liquid cloud layer, are retrieved using an optimal estimation–based physical retrieval algorithm from AERI-observed Radiance data. This algorithm provides a full error covariance matrix for the solution, and both the degrees of freedom for signal and the Shannon information content. The algorithm is evaluated with both synthetic and real AERI observations. The AERI is shown to have approximately 85% and 70% of its information in the lowest 2 km of the atmosphere for temperature and water vapor profiles, respectively. In clear-sky situations, the mean bias errors with respect to the radiosonde profiles are less than 0.2 K and 0.3 g kg−1 for heights below 2 km for temperature and water vapor mixing ratio, respecti...