Dr. Denis Elliott Profile

Dr. Denis Elliott

AIRS Operations Manager at Jet Propulsion Lab

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Author

Publications (28)

Proceedings Article | 19 September 2016 Presentation + Paper

Comparison of the AIRS, IASI, and CrIS 900 cm-1 channel for Dome Concordia

H. Aumann, Denis Elliott, Evan Manning

Proceedings Volume 9972, 997209 (2016) https://doi.org/10.1117/12.2235945

KEYWORDS: Calibration, Climate change, Infrared radiation, Calibration, Temperature metrology, Radiometry, Radon, Domes, Spectral calibration, Pollution control, Current controlled current source

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Proceedings Article | 8 September 2015 Paper

Improving AIRS radiance spectra in high contrast scenes using MODIS

Thomas Pagano, Hartmut Aumann, Evan Manning, Denis Elliott, Steven Broberg

Proceedings Volume 9607, 96070K (2015) https://doi.org/10.1117/12.2188311

KEYWORDS: MODIS, Point spread functions, Infrared radiation, Sensors, Calibration, Clouds, Space operations, Spectral calibration, Data acquisition, Spatial resolution

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The Atmospheric Infrared Sounder (AIRS) on the EOS Aqua Spacecraft was launched on May 4, 2002. AIRS acquires hyperspectral infrared radiances in 2378 channels ranging in wavelength from 3.7-15.4 um with spectral resolution of better than 1200, and spatial resolution of 13.5 km with global daily coverage. The AIRS is designed to measure temperature and water vapor profiles for improvement in weather forecast accuracy and improved understanding of climate processes. As with most instruments, the AIRS Point Spread Functions (PSFs) are not the same for all detectors. When viewing a non-uniform scene, this causes a significant radiometric error in some channels that is scene dependent and cannot be removed without knowledge of the underlying scene. The magnitude of the error depends on the combination of non-uniformity of the AIRS spatial response for a given channel and the non-uniformity of the scene, but is typically only noticeable in about 1% of the scenes and about 10% of the channels. The current solution is to avoid those channels when performing geophysical retrievals. In this effort we use data from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument to provide information on the scene uniformity that is used to correct the AIRS data. For the vast majority of channels and footprints the technique works extremely well when compared to a Principal Component (PC) reconstruction of the AIRS channels. In some cases where the scene has high inhomogeneity in an irregular pattern, and in some channels, the method can actually degrade the spectrum. Most of the degraded channels appear to be slightly affected by random noise introduced in the process, but those with larger degradation may be affected by alignment errors in the AIRS relative to MODIS or uncertainties in the PSF. Despite these errors, the methodology shows the ability to correct AIRS radiances in non-uniform scenes under some of the worst case conditions and improves the ability to match AIRS and MODIS radiances in non-uniform scenes.

Proceedings Article | 8 September 2015 Paper

Calibration and data analysis issues in modern infrared spectrometers using large detector arrays

Denis Elliott, Hartmut Aumann

Proceedings Volume 9607, 96070M (2015) https://doi.org/10.1117/12.2186680

KEYWORDS: Sensors, Calibration, Infrared radiation, Infrared detectors, Spectrometers, Detector arrays, Photovoltaics, Infrared spectroscopy, Data analysis, Infrared sensors

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Proceedings Article | 1 September 2015 Paper

Performance status of the AIRS instrument thirteen years after launch

Denis Elliott, Thomas Pagano, Hartmut Aumann, Steven Broberg

Proceedings Volume 9611, 961109 (2015) https://doi.org/10.1117/12.2186608

KEYWORDS: Sensors, Lamps, Infrared radiation, Space operations, Calibration, Climatology, Data modeling, Clouds, Photovoltaics, Spectroscopy

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Proceedings Article | 25 September 2014 Paper

Comparison of AIRS, IASI, and CrIS radiances and trends at Dome C

Denis Elliott, Hartmut Aumann

Proceedings Volume 9218, 92180D (2014) https://doi.org/10.1117/12.2061079

KEYWORDS: Temperature metrology, Satellites, Infrared radiation, Calibration, Thermal effects, Domes, Infrared sensors, Sensors, Atmospheric sensing, Interferometers

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Proceedings Article | 23 September 2013 Paper

Calibration status of the Atmospheric Infrared Sounder after eleven years in operation

Denis Elliott, Margie Weiler, Evan Manning, Thomas Pagano, Steven Broberg, Hartmut Aumann

Proceedings Volume 8866, 88660T (2013) https://doi.org/10.1117/12.2024585

KEYWORDS: Calibration, Mirrors, Sensors, Infrared radiation, Space mirrors, Climatology, Polarization, Environmental sensing, Black bodies, Space operations

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Proceedings Article | 9 November 2012 Paper

Performance status of the Atmospheric Infrared Sounder ten years after launch

Thomas Pagano, Steve Broberg, Hartmut Aumann, Denis Elliott, Evan Manning, Larrabee Strow

Proceedings Volume 8527, 852703 (2012) https://doi.org/10.1117/12.977309

KEYWORDS: Infrared radiation, Sensors, Calibration, Spectroscopy, Mirrors, Infrared spectroscopy, Signal to noise ratio, Space operations, Black bodies, Staring arrays

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Proceedings Article | 25 October 2012 Paper

Validation of the radiometric stability of the Atmospheric Infrared Sounder

H. Aumann, D. Elliott, L. Strow

Proceedings Volume 8510, 85100T (2012) https://doi.org/10.1117/12.929979

KEYWORDS: Carbon dioxide, Shortwaves, Calibration, Infrared radiation, Climatology, Ozone, Clouds, NOx, Temperature metrology, Stratosphere

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It has been widely accepted that an infrared sounder in low polar orbit is capable of producing climate quality data, if the spectral brightness temperatures have instrumental trends of less than 10 mK/yr. Achieving measurement stability at this level is not only very demanding of the design of the instrument, it is also pushes the state of art of measuring on orbit what stability is actually achieved. We discuss this using Atmospheric Infrared Sounder (AIRS) L1B data collected between 2002 and 2011. We compare the L1B brightness temperature observed in cloud filtered night tropical ocean spectra (obs) to the brightness temperature calculated based on the known surface emissivity, temperature and water vapor profiles from the ECMWF ReAnalysis (ERA) and the growth rates of CO₂ , N₂O and Ozone. The trend in (obscalc) is a powerful tool for the evaluation of the stability of the 2378 AIRS channels. We divided the channels into seven classes: All channels which sound in the stratosphere (at pressure levels below 150 hPa), 14 um CO₂ sounding, 4 um CO₂ P-branch sounding, 4um CO₂ R-branch sounding, water vapor sounding, shortwave surface sounding and longwave surface sounding. The peak in the weighting function at 1050 hPa separates sounding and surface channels. The boundary between shortwave and longwave is 5 μm. Except for the stratosphere sounding channels, the remaining six groups have (obs-calc) trends of less than 20 mK/yr. The longwave surface channels have trends of 2 mK/yr, significantly less than the 8 mK/yr trend seem in the shortwave window channels. Based on the design of the instrument, trends within a group of channels should be the same. While the longwave and shortwave trends are less than the canonical 10 mK/yr, the larger trend in the shortwave channels could be an artifact of using the pre-launch determined calibration coefficients. This is currently under evaluation. The trend in (obs-calc) for the non-surface sounding channels, in particular for stratosphere sounding and upper tropospheric water channels, is dominated by artifacts created in calc, most likely due to changes in the ERA Ozone and water vapor. Based on this argument the best estimate of the trend for the channels within a channel group is given by the surface sensitive channels within the group. Based on this consideration we estimated the trend of all AIRS longwave channels as 2 mK/yr, while the shortwave channels have a trend of 8 mK/yr.

Proceedings Article | 15 October 2012 Paper

Level-1C product from AIRS: principal component filtering

Evan Manning, Yibo Jiang, Hartmut Aumann, Denis Elliott, Scott Hannon

Proceedings Volume 8510, 85100V (2012) https://doi.org/10.1117/12.928546

KEYWORDS: Principal component analysis, Spectroscopy, Climatology, Sensors, Calibration, Clouds, Infrared radiation, Error analysis, Diamond, Space operations

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Proceedings Article | 15 October 2012 Paper

Relative trends of AIRS and IASI radiometric calibrations

Denis Elliott, Hartmut Aumann

Proceedings Volume 8510, 85100S (2012) https://doi.org/10.1117/12.930045

KEYWORDS: Calibration, Clouds, Temperature metrology, Climatology, Infrared radiation, Electroluminescence, Lanthanum, Space operations, Spatial coherence, Imaging systems

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Proceedings Article | 14 September 2011 Paper

Evaluation of cloudy data as stable references for climate research using AIRS and IRIS data

Hartmut Aumann, Yibo Jiang, Denis Elliott

Proceedings Volume 8153, 815304 (2011) https://doi.org/10.1117/12.892797

KEYWORDS: IRIS Consortium, Clouds, Calibration, Infrared radiation, Climatology, Radiometry, Infrared spectroscopy, Satellites, Climate change, Spectral resolution

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Proceedings Article | 14 September 2011 Paper

Sensitivity of AIRS and IASI radiometric calibration to scene temperature

Denis Elliott, Hartmut Aumann

Proceedings Volume 8153, 815303 (2011) https://doi.org/10.1117/12.893795

KEYWORDS: Temperature metrology, Climatology, Calibration, Environmental sensing, Spectroscopy, Infrared radiation, Clouds, Fourier transforms, Spectral resolution, Space operations

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Proceedings Article | 27 August 2010 Paper

Comparison of AIRS and IASI co-located radiances for cold scenes

Denis Elliott, H. Aumann, Steven Broberg

Proceedings Volume 7807, 78070J (2010) https://doi.org/10.1117/12.860964

KEYWORDS: Calibration, Temperature metrology, Climatology, Infrared radiation, Domes, Sensors, Analytical research, Environmental sensing, Spectral calibration, Infrared sensors

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Proceedings Article | 26 August 2010 Paper

Systems approach to developing a climate data record from satellite observations

Steve Broberg, Thomas Pagano, Hartmut Aumann, Denis Elliott, Fred O'Callaghan

Proceedings Volume 7813, 78130C (2010) https://doi.org/10.1117/12.862073

KEYWORDS: Climatology, Environmental sensing, Calibration, Data archive systems, Infrared radiation, Spectroscopy, Fourier transforms, Sensors, Satellites, Black bodies

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Proceedings Article | 12 August 2009 Paper

Two-year comparison of radiances from the Atmospheric Infrared Sounder (AIRS) and the Infrared Atmospheric Sounding Interferometer (IASI)

Denis Elliott, Hartmut Aumann, L. Larrabee Strow, Scott Hannon

Proceedings Volume 7456, 74560S (2009) https://doi.org/10.1117/12.826996

KEYWORDS: Infrared radiation, Calibration, Interferometers, Climatology, Spectroscopy, Space operations, Atmospheric corrections, Environmental sensing, Spectral calibration, Phase modulation

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Proceedings Article | 20 August 2008 Paper

Level 1C spectra from the Atmospheric Infrared Sounder (AIRS)

Denis Elliott, Hartmut Aumann, Yibo Jiang, Steven Broberg

Proceedings Volume 7081, 70810L (2008) https://doi.org/10.1117/12.795491

KEYWORDS: Climatology, Spectroscopy, Calibration, Infrared radiation, Sensors, Principal component analysis, Error analysis, Environmental sensing, Spectral calibration, Temperature metrology

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Proceedings Article | 20 August 2008 Paper

Absolute radiometric calibration accuracy of the Atmospheric Infrared Sounder (AIRS)

Thomas Pagano, Hartmut Aumann, Rudolf Schindler, Denis Elliott, Steve Broberg, Kenneth Overoye, Margaret Weiler

Proceedings Volume 7081, 70811B (2008) https://doi.org/10.1117/12.795445

KEYWORDS: Calibration, Black bodies, Polarization, Mirrors, Infrared radiation, Spectroscopy, Sensors, Temperature sensors, Scattering, Data modeling

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Proceedings Article | 27 September 2007 Paper

Contributions to climate studies from four years of hyperspectral data from the Atmospheric Infrared Sounder (AIRS)

Denis Elliott, Hartmut Aumann, L. Larrabee Strow, David Gregorich

Proceedings Volume 6677, 667714 (2007) https://doi.org/10.1117/12.732662

KEYWORDS: Temperature metrology, Calibration, Climatology, Infrared radiation, Space operations, Climate change, Domes, Spectral calibration, Spectral resolution, Clouds

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Proceedings Article | 8 December 2006 Paper

Version 5 product improvements from the atmospheric infrared sounder (AIRS)

Thomas Pagano, Hartmut Aumann, Moustafa Chahine, Evan Manning, Steve Friedman, Steven Broberg, Stephen Licata, Denis Elliott, Fredrick Irion, Brian Kahn, Evan Fishbein, Edward Olsen, Stephanie Granger, Joel Susskind, Fricky Keita, John Blaisdell, Larrabee Strow, Sergio DeSouza-Machado, Chris Barnet

Proceedings Volume 6408, 640808 (2006) https://doi.org/10.1117/12.696561

KEYWORDS: Clouds, Infrared radiation, Ozone, Carbon monoxide, Yield improvement, Microwave radiation, Climatology, Error analysis, Methane, Calibration

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Proceedings Article | 8 September 2006 Paper

The impact of the AIRS spatial response on channel-to-channel and multi-instrument data analyses

Denis Elliott, Thomas Pagano, H. Aumann

Proceedings Volume 6296, 62960I (2006) https://doi.org/10.1117/12.679542

KEYWORDS: MODIS, Collimators, Mirrors, Infrared radiation, Sensors, Spectral resolution, Spectroscopy, Scanners, Infrared imaging, Space operations

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Proceedings Article | 4 May 2006 Paper

Lessons from three years of hyperspectral data from the Atmospheric Infrared Sounder (AIRS) on the EOS AQUA

Hartmut Aumann, Denis Elliott, Dave Gregorich

Proceedings Volume 6233, 623318 (2006) https://doi.org/10.1117/12.666222

KEYWORDS: Clouds, Calibration, Infrared radiation, Contamination, Temperature metrology, Optical filters, Skin, Spectrometers, Spatial coherence, Space operations

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More than three years of data from the Atmospheric InfraRed Sounder (AIRS) have given many new insights into infrared hyperspectral sounding from space. Among other things they have shown that 1) Absolute accuracy at the 200 mK level and stability at the better than 20 mK/year level can be deduced for the AIRS data by comparing the observed brightness temperatures with those predicted by NOAA/NCEP's RTGSST for surface channels and those predicted from the ECMWF temperature and moisture profiles for all channels except those sensitive to stratospheric temperatures or water vapor. While the 2616 cm^-1 window channel used with AIRS for the validation of the calibration relative to the RTGSST is superior, the 1231 cm^-1 window channel can be used for IASI and CRIS with slightly degraded accuracy. 2) Residual cloud contamination of about 240 mK for tightly cloud-filtered data establishes an effective noise floor for channels with weighting function below the cloud tops. With the AIRS 13.5 km footprints and mean NeDT of 0.2 K, the noise floor is reached by filtering out all but 2% of the spectra. 3) The absolute value of the difference between adjacent clear ocean footprints at night provides an excellent estimate of the NeDT in all spectral regions not affected by water vapor. Water vapor spatial scene inhomogeneity on a 13.5 km scale even in clear footprints acts as a source of noise up to a factor of six larger than the NeDT in water sensitive channels. The methodology established by AIRS for system performance evaluation and trend analysis, including the use of the RTGSST and the ECMWF profiles, lays the foundation and establishes the benchmark for the validation of the performance of future hyperspectral sounders. AIRS was launched into polar 705 km altitude orbit on the EOS Aqua spacecraft on May 4, 2002. It covers the 3.7 to 15.4 micron region of the thermal infrared spectrum with spectral resolution of 1200. Since the start of routine data gathering in September 2002 AIRS has returned 2.9 million spectra of the upwelling radiance each day.

Proceedings Article | 29 August 2005 Paper

Improving AIRS spatial co-registration by resampling

Thomas Pagano, Denis Elliott, Hartmut Aumann, Steven Broberg, Steven Gaiser, Rudolf Schindler, Moustafa Chahine

Proceedings Volume 5890, 58900Q (2005) https://doi.org/10.1117/12.616237

KEYWORDS: Infrared radiation, Staring arrays, Infrared imaging, Mirrors, Electroluminescence, Calibration, Spectral resolution, Detector arrays, Error analysis, Satellites

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Proceedings Article | 22 August 2005 Paper

Performance of the Atmospheric Infrared Sounder (AIRS) in the radiation environment of low-earth orbit

Margaret Weiler, Kenneth Overoye, James Stobie, Paul O'Sullivan, Steven Gaiser, Steven Broberg, Denis Elliott

Proceedings Volume 5882, 588210 (2005) https://doi.org/10.1117/12.615244

KEYWORDS: Calibration, Radiation effects, Infrared radiation, Sensors, Staring arrays, Readout integrated circuits, Earth's atmosphere, Mercury cadmium telluride, Signal processing, Space operations

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Proceedings Article | 1 June 2005 Paper

Channel alignment and radiometry in hyperspectral atmospheric infrared sounders

Denis Elliott, H. Aumann, Thomas Pagano, Kenneth Overoye, Rudolf Schindler

Proceedings Volume 5806, (2005) https://doi.org/10.1117/12.604450

KEYWORDS: Sensors, Infrared radiation, Clouds, Detector arrays, Radiometry, Climatology, Calibration, Space operations, Ocean optics, Atmospheric sciences

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Proceedings Article | 26 October 2004 Paper

Stephen Licata, Steven Broberg, Denis Elliott, Steven Gaiser

Proceedings Volume 5542, (2004) https://doi.org/10.1117/12.557362

KEYWORDS: Calibration, MATLAB, Data archive systems, Data centers, Data processing, Space operations, Binary data, Microwave radiation, Databases, Inspection

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Proceedings Article | 26 October 2004 Paper

AIRS infrared polarization sensitivity and in-flight observations

Thomas Pagano, Hartmut Aumann, Denis Elliott, Steven Broberg

Proceedings Volume 5542, (2004) https://doi.org/10.1117/12.557435

KEYWORDS: Polarization, Infrared radiation, Mirrors, Spectroscopy, Signal detection, Sensors, Calibration, Atmospheric sensing, Space operations, Instrument modeling

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Proceedings Article | 10 November 2003 Paper

AIRS/AMSU/HSB on EOS Aqua: first-year post-launch assessment

Thomas Pagano, Moustafa Chahine, Hartmut Aumann, Denis Elliott, Evan Manning, Vincent Realmuto, Charles Thompson, Bjorn Lambrigtsen, Sung-Yung Lee, Steve Broberg, Edward Olsen, Eric Fetzer, Larrabee Strow

Proceedings Volume 5151, (2003) https://doi.org/10.1117/12.504915

KEYWORDS: Infrared radiation, Calibration, Microwave radiation, Clouds, Temperature metrology, Sensors, Climatology, Infrared spectroscopy, Spectroscopy, Humidity

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Proceedings Article | 18 January 2002 Paper

Operational readiness for the atmospheric infrared sounder (AIRS) on the Earth Observing System Aqua spacecraft

Thomas Pagano, Denis Elliot, Michael Gunson, Hartmut Aumann, Steven Gaiser, Navid Dehghani, Kenneth Overoye

Proceedings Volume 4483, (2002) https://doi.org/10.1117/12.453468

KEYWORDS: Calibration, Infrared radiation, Earth's atmosphere, Space operations, Climatology, Temperature metrology, Lamps, Infrared spectroscopy, Spectroscopy, Mirrors

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Showing 5 of 28 publications

Proceedings Volume Editor (1)

SPIE Conference Volume | 21 November 1980

Applications of Digital Image Processing to Astronomy

Conference Committee Involvement (1)

Applications of Digital Image Processing to Astronomy

20 August 1980 | Los Angeles, United States

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