Mr. Robert S. Wilson Profile

Robert S. Wilson

at Science Systems and Applications Inc

SPIE Involvement:

Author

Publications (51)

Proceedings Article | 9 September 2019 Presentation + Paper

Performance trends of Clouds and the Earth’s Radiant Energy System (CERES) instruments aboard terra, aqua, S-NPP and NOAA-20 missions

Susan Thomas, K. Priestley, M. Shankar, P. Hess, R. Wilson, N. Smith, D. Walikainen, Z. Szewczyk

Proceedings Volume 11127, 1112716 (2019) https://doi.org/10.1117/12.2530828

KEYWORDS: Sensors, Shortwaves, Calibration, Space operations, Clouds, Sensor calibration, Instrument modeling, Sensor performance, Black bodies, Lamps

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Clouds and the Earth’s Radiant Energy System (CERES) instrument was designed to provide accurate measurements for the long-term monitoring of Earth’s radiation energy budget. Seven copies of the CERES instruments were built by Northrop Grumman Aerospace Systems (NGAS) and has been flying aboard five spacecraft platforms. The CERES instrument with the three scanning sensors measure radiances in 0.3 to 5.0 micron region with Shortwave sensor, 0.3 to >100 microns with Total sensor, and either a 8 - 12 micron region Window sensor on the first six instruments or a 5 – 35 micron longwave sensor on the seventh Flight Model 6 (FM6) instrument. Currently there are six instruments actively collecting Longwave and Shortwave measurements. Four of the CERES instruments (Flight Models1 through 4) fly aboard Earth Observing System (EOS) Terra and Aqua platforms with two instruments aboard each spacecraft. Flight Models 5 and 6 are aboard the Suomi-NPP and NOAA-20 spacecrafts. The pre-launch accuracy goal for the CERES instrument measurements is to have the emitted longwave radiances within 0.5% and the shortwave radiances within 1.0%. The in-flight evaluation of the sensor performance are carried out using the internal calibration module (ICM) comprising of blackbody sources and tungsten lamp, and a solar diffuser plate known as the Mirror Attenuator Mosaic (MAM). The ICM and MAM calibration results are instrumental in understanding the ground to flight shift and in-flight drifts in CERES sensors’ gains. In addition, several validation studies utilising targets such as tropical ocean and deep convective clouds are performed as part of the Cal/Val protocol. Comparisons of sensor measurements from instruments on the same spacecraft as well as coincident measurements of CERES instruments on different spacecraft at overpass regions are also performed to support the intercomparison studies between the sensors of different instruments. The calibration and validation studies collectively provide good understanding of the instrument performance and any changes occuring at different spectral regions of the sensors. This paper discusses the various studies utilized to evaluate the sensor perform.

Proceedings Article | 18 September 2018 Presentation

Ensuring continuity of earth radiation budget observations initial results of CERES FM-6 on NOAA-20 (Conference Presentation)

Kory Priestley, Susan Thomas, Nathaniel Smith, Janet Daniels, Robert Wilson, Dale Walikainen, Anum Ashraf

Proceedings Volume 10764, 107640Q (2018) https://doi.org/10.1117/12.2321645

KEYWORDS: Calibration, Space operations, Clouds, Climatology

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Proceedings Article | 7 September 2018 Paper

Early trends on the Clouds and the Earth's Radiant Energy System (CERES) Flight Model 6 (FM6) instrument's performance

Nathaniel Smith, Robert Wilson, Z. Peter Szewczyk, Susan Thomas, Kory Priestley

Proceedings Volume 10764, 107640R (2018) https://doi.org/10.1117/12.2322712

KEYWORDS: Calibration, Sensors, Shortwaves, Clouds, Space operations, Black bodies, Solar radiation, Satellites

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Proceedings Article | 8 September 2015 Paper

Assessment of the clouds and the Earth’s Radiant Energy System (CERES) instrument performance and stability on the Aqua, Terra, and S-NPP spacecraft

Nathaniel Smith, Susan Thomas, Mohan Shankar, Phillip Hess, Natividad Smith, Dale Walikainen, Robert Wilson, Kory Priestley

Proceedings Volume 9607, 96070T (2015) https://doi.org/10.1117/12.2190110

KEYWORDS: Calibration, Sensors, Shortwaves, Space operations, Solar radiation, Satellites, Clouds, Solar energy, Black bodies, Radiometry

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Proceedings Article | 26 September 2014 Paper

Assessment of the clouds and the Earth's radiant energy system (CERES) flight model 5 (FM5) instrument's performance and stability

Nathaniel Smith, Susan Thomas, Mohan Shankar, Z. Szewczyk, Robert Wilson, Dale Walikainen, Janet Daniels, Phillip Hess, Kory Priestley

Proceedings Volume 9218, 921802 (2014) https://doi.org/10.1117/12.2061833

KEYWORDS: Calibration, Sensors, Shortwaves, Black bodies, Satellites, Solar radiation, Space operations, Solar radiation models, Clouds, Instrument modeling

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Proceedings Article | 23 September 2013 Paper

Performance assessment of the Clouds and the Earth's Radiant Energy System (CERES) instruments aboard Terra and Aqua spacecraft

Susan Thomas, K. Priestley, M. Shankar, N. Smith, N. Loeb, D. Walikainen, P. Hess, R. Wilson

Proceedings Volume 8866, 886606 (2013) https://doi.org/10.1117/12.2024963

KEYWORDS: Sensors, Shortwaves, Calibration, Space operations, Clouds, Sensor calibration, Black bodies, Bolometers, Lamps, Tungsten

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Clouds and the Earth's Radiant Energy System (CERES) instruments were designed to measure the reflected shortwave and emitted longwave radiances of the Earth’s radiation budget and to investigate the cloud interactions with global radiances for the long-term monitoring of Earth's climate. The three scanning thermistor bolometer sensors on CERES measure broadband radiances in the shortwave (0.3 to 5.0 micrometer), total (0.3 to <100 micrometer) and in 8 - 12 micrometer water vapor window regions. Of the five CERES instruments that are currently in operation, four of the CERES instruments (Flight Models1 through 4) fly aboard Earth Observing System (EOS) Terra and Aqua platforms with two instruments aboard each spacecraft, in 705 KM sun-synchronous orbits of 10:30 AM and 1:30 PM equatorial crossing time.

A rigorous and comprehensive radiometric calibration and validation protocol comprising of various studies was developed to evaluate the calibration accuracy of the CERES instruments. The in-flight calibration of CERES sensors are carried out using the internal calibration module (ICM) comprising of blackbody sources and quartzhalogen tungsten lamp, and a solar diffuser plate known as the Mirror Attenuator Mosaic (MAM). The ICM calibration results are instrumental in determining the changes in CERES sensors’ gains after launch from the prelaunch determined values and the on-orbit gain variations. In addition to the broadband response changes derived from the on-board blackbody and the tungsten lamp, the shortwave and the total sensors show a spectrally dependent drop in responsivity in the shorter wavelegth region below one micron that were brought to light through validation studies. The spectrally dependent changes were attributed to the instrument operational modes and the corrections were derived using the sensor radiance comparisons. This paper covers the on-orbit behavior of CERES sensors aboard the Terra and Aqua spacecraft and the determination of the sensor response changes utilising the in-flight calibration and the radiance measurement comparisons viewing various targets. The corrections for the sensor response changes were incorporated in the radiance calculations of CERES Edition3 data products.

Proceedings Article | 23 September 2013 Paper

On-orbit solar calibration methods using the Clouds and Earth's Radiant Energy System (CERES) in-flight calibration system: lessons learned

Robert Wilson, Kory Priestley, Susan Thomas, Phillip Hess, Mohan Shankar, Nathaniel Smith, Peter Szewczyk

Proceedings Volume 8866, 886607 (2013) https://doi.org/10.1117/12.2025967

KEYWORDS: Calibration, Shortwaves, Sensors, Solar energy, Bolometers, Diffusers, Sun, Solar radiation, Space operations, Mirrors

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The Clouds and Earth's Radiant Energy System (CERES) scanning thermistor bolometers measure earth-reflected solar and earth-emitted long-wave radiances, at the top- of-the-atmosphere. The bolometers measure the earth radiances in the broadband shortwave solar (0.3-5.0 microns) and total (0.3->100 microns) spectral bands as well as in the 8->12 microns water vapor window spectral band over geographical footprints as small as 10 kilometers at nadir. December 1999, the second and third set of CERES bolometers was launched on the Earth Observing Mission Terra Spacecraft. May 2003, the fourth and fifth set of bolometers was launched on the Earth Observing Mission Aqua Spacecraft. Recently, (October 2011) the sixth instrument was launched on the National Polar-orbiting Operational Environmental Satellite System Preparatory Project (Suomi NPP) Spacecraft. Ground vacuum calibrations define the initial count conversion coefficients that are used to convert the bolometer output voltages into filtered earth radiances. The mirror attenuator mosaic (MAM), a solar diffuser plate, was built into the CERES instrument package calibration system in order to define on-orbit shifts or drifts in the sensor responses. It followed a similar design as the Earth Radiation Budget Experiment (ERBE) scanners with improvements from lessons learned.

The shortwave and shortwave part of the total-wave sensors are calibrated using the solar radiances reflected from the MAM's. Each MAM consists of baffle-solar diffuser plate systems, which guide incoming solar radiances into the instrument fields of view of the shortwave and total wave sensor units. The MAM diffuser reflecting type surface consists of an array of spherical aluminum mirror segments, which are separated by a Merck Black A absorbing surface, over-coated with SIOx (SIO2 for PFM). Thermistors are located within each MAM plate and the total channel baffle. The CERES MAM is designed to yield calibration precisions approaching .5 percent for the total and shortwave detectors. The Terra FM1 and FM2 shortwave channels and the FM1 and FM2 total channels MAM calibration systems showed shifts in their solar calibrations of 1.5, 2.5, 1.5 and 6 percent, respectively within the first year. The Aqua FM3, and FM4 shortwave channels and the FM3 and FM4 total channels MAM calibration systems showed shifts in their solar calibrations of 1.0, 1.2, 2.1 and .8 percent, respectively within the first year. A possible explanation has attributed the MAM reflectance change to on-orbit solar ultraviolet/atomic oxygen/out-gassing induced chemical changes to the SIOx coated MAM assembly during ram and solar exposure. There is also changes to the sensor telescope shortwave filters as well as the Total channel mirrors and/or sensors. The Soumi NPP FM5 is still after 2.5 years displaying a stability of less than .5 percent. In this presentation, lessons learned from the ERBE MAM and application of knowledge of how the space environment affected the CERES FM1-4 solar calibrations will be presented along with on-orbit measurements for the thirteen years the CERES instruments have been on-orbit.

Proceedings Article | 19 October 2012 Paper

Performance of the Clouds and the Earth's Radiant Energy System (CERES) Flight Model 5 (FM5) instrument on NPP mission

Susan Thomas, Kory Priestley, Phillip Hess, Robert Wilson, Nathaniel Smith, Mark Timcoe, Mohan Shankar, Dale Walikainen

Proceedings Volume 8510, 851005 (2012) https://doi.org/10.1117/12.930775

KEYWORDS: Sensors, Calibration, Shortwaves, Space operations, Clouds, Instrument modeling, Systems modeling, Lamps, Aerospace engineering, Diffusers

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Proceedings Article | 15 October 2012 Paper

On-orbit solar calibration methods using the Clouds and Earth's Radiant Energy System (CERES) in-flight calibration system

Robert Wilson, Kory Priestley, Susan Thomas, Phillip Hess

Proceedings Volume 8510, 851003 (2012) https://doi.org/10.1117/12.930922

KEYWORDS: Calibration, Shortwaves, Sensors, Sun, Solar energy, Bolometers, Diffusers, Space operations, Raster graphics, Radiometry

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The Clouds and Earth's Radiant Energy System (CERES) scanning thermistor bolometers measure earth-reflected solar and earth-emitted longwaveradiances, at the top- of-the-atmosphere. The bolometers measure the earthradiances in the broadband shortwave solar (0.3-5.0 microns) and total (0.3-<100 microns) spectral bands as well as in the 8-<12 microns water vapor window spectral band over geographical footprints as small as 10 kilometers at nadir. December 1999, the second and third set of CERES bolometers was launchedon the Earth Observing Mission Terra Spacecraft. May 2003, the fourth and fifth set of bolometers was launched on the Earth Observing Mission Aqua Spacecraft. Recently, (October 2011) the sixth instrument was launched on the National Polar-orbiting Operational Environmental Satellite System Preparatory Project (Suomi NPP) Spacecraft. Ground vacuum calibrations define the initial count conversion coefficients that are used to convert the bolometer output voltages into filtered earth radiances. The mirror attenuator mosaic (MAM), a solar diffuser plate, was built into the CERES instrument package calibration system in order to define in-orbit shifts or drifts in the sensor responses. The shortwave and shortwave part of the total sensors are calibrated using the solar radiances reflected from the MAM's. Each MAM consists of baffle-solar diffuser plate systems, which guide incoming solar radiances into the instrument fields of view of the shortwave and total wave sensor units. The MAM diffuser reflecting type surface consists of an array of spherical aluminum mirror segments, which are separated by a Merck Black A absorbing surface, overcoated with SIOx (SIO2 for PFM). Thermistors are located in each MAM plate and the total channel baffle. The CERES MAM is designed to yield calibration precisions approaching .5 percent for the total and shortwave detectors. In this presentation, the MAM solar calibration contrasting procedures will be presented along with on-orbit measurements for the eleven years the CERES instruments have been on-orbit. A switch to an azimuth rotation raster scan of the Sun rather than a fixed azimuth rotating elevation scan will be discussed. Comparisons are also made between the Terra, Aqua, and Suomi NPP CERES instruments during their MAM solar calibrations and total solar irradiance experimental results to determine how precise the CERES solar calibration facilities are at tracking the sun's irradiance.

Proceedings Article | 11 November 2010 Paper

Characterization of the clouds and the Earth's radiant energy system (CERES) sensors on Terra and Aqua spacecraft

Susan Thomas, K. Priestley, N. Smith, N. Loeb, P. Hess, M. Shankar, D, Walikainen, Z. Szewczyk, R. Wilson, D. Cooper

Proceedings Volume 7862, 78620N (2010) https://doi.org/10.1117/12.869684

KEYWORDS: Sensors, Shortwaves, Calibration, Space operations, Black bodies, Sensor calibration, Lamps, Clouds, Tungsten, Bolometers

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Proceedings Article | 28 August 2010 Paper

On-orbit solar calibrations using the Clouds and Earth's Radiant Energy System (CERES) in-flight calibration system

Robert Wilson, Kory Priestley, Susan Thomas, Phillip Hess

Proceedings Volume 7807, 78070D (2010) https://doi.org/10.1117/12.862172

KEYWORDS: Calibration, Shortwaves, Sensors, Sun, Solar energy, Bolometers, Diffusers, Space operations, Radiometry, Clouds

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The Clouds and Earth's Radiant Energy System (CERES) scanning thermistor bolometers measure earth-reflected solar and earth-emitted longwaveradiances, at the top- of-the-atmosphere. The bolometers measure the earthradiances in the broadband shortwave solar (0.3-5.0 microns) and total (0.3->100 microns) spectral bands as well as in the 8->12 microns water vapor window spectral band over geographical footprints as small as 10 kilometers at nadir. December 1999, the second and third set of CERES bolometers was launchedon the Earth Observing Mission Terra Spacecraft. May 2003, the fourth and fifth set of bolometers was launched on the Earth Observing Mission Aqua Spacecraft. Ground vacuum calibrations define the initial count conversion coefficients that are used to convert the bolometer output voltages into filtered earth radiances. The mirror attenuator mosaic (MAM), a solar diffuser plate, was built into the CERES instrument package calibration system in order to define in-orbit shifts or drifts in the sensor responses. The shortwave and shortwave part of total sensors are calibrated using the solar radiances reflected from the MAM's. Each MAM consists of baffle-solar diffuser plate systems, which guide incoming solar radiances into the instrument fields of view of the shortwave and total wave sensor units. The MAM diffuser reflecting type surface consists of an array of spherical aluminum mirror segments, which are separated by a Merck Black A absorbing surface, overcoated with SIOx. Thermistors are located in each MAM plate and the total channel baffle. The CERES MAM is designed to yield calibration precisions approaching .5 percent for the total and shortwave detectors. However, in their first year of operation the Terra and Aqua MAMs showed shifts in their calibrations larger than expected. Shifts of this nature have been seen in other Solar viewing instruments in the past. A possible explanation has attributed the changes to pre-orbit or on-orbit contamination combined with solar ultraviolet/atomic oxygen induced chemical changes to the contaminant during solar exposure. In the subsequent year of operation all instruments begin to stabilize within the .5 percent precision range. In this presentation, the MAM solar calibration procedures will be presented along with on-orbit measurements for the nine years the CERES instruments have been on-orbit. A switch to an azimuth rotation raster scan of the Sun rather than an elevation scan will be discussed. The implementation of a thermal correction to the shortwave channel will also be discussed. Comparisons are also made between the Terra CERES instruments and the Aqua instruments during their MAM solar calibrations and total solar irradiance experimental results to determine how precise the CERES solar calibration facilities are at tracking the sun's irradiance.

Proceedings Article | 28 August 2009 Paper

Sensor performance of Clouds and the Earth's Radiant Energy System (CERES) instruments aboard EOS Terra and Aqua spacecraft based on post-launch calibration studies

Susan Thomas, K. Priestley, P. Hess, R. Wilson, M. Avery, D. Walikainen, Z. P. Szewczyk, D. Cooper, M. Shankar

Proceedings Volume 7452, 74520I (2009) https://doi.org/10.1117/12.828487

KEYWORDS: Sensors, Shortwaves, Calibration, Space operations, Clouds, Black bodies, Lamps, Tungsten, Sensor calibration, Sensor performance

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Proceedings Article | 26 August 2009 Paper

On-orbit solar calibrations using the Aqua Clouds and Earth's Radiant Energy System (CERES) in-flight calibration system

Robert Wilson, Kory Priestley, Susan Thomas, Phillip Hess

Proceedings Volume 7452, 74520J (2009) https://doi.org/10.1117/12.827305

KEYWORDS: Calibration, Sensors, Shortwaves, Solar energy, Sun, Bolometers, Diffusers, Space operations, Radiometry, Clouds

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Proceedings Article | 5 October 2007 Paper

Radiometric performance of the CERES Earth radiation budget climate record sensors on the EOS Aqua and Terra spacecraft

Kory Priestley, G. Louis Smith, Susan Thomas, Denise Cooper, Robert Lee, Dale Walikainen, Phil Hess, Z. Peter Szewczyk, Robert Wilson

Proceedings Volume 6677, 66770H (2007) https://doi.org/10.1117/12.735294

KEYWORDS: Calibration, Shortwaves, Space operations, Climatology, Sensors, Black bodies, Optical filters, Environmental sensing, Earth's atmosphere, Radiometry

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Proceedings Article | 8 December 2006 Paper

Radiometric stability results of clouds and the Earth's radiant energy system (CERES) instrument sensors aboard EOS Terra and Aqua spacecraft

Susan Thomas, K. Priestley, R. Wilson, G. Matthews, D. Walikainen, D. Cooper, P. Hess

Proceedings Volume 6408, 640805 (2006) https://doi.org/10.1117/12.694077

KEYWORDS: Sensors, Shortwaves, Calibration, Space operations, Clouds, Sensor calibration, Black bodies, Diffusers, Lamps, Mirrors

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Proceedings Article | 20 September 2006 Paper

Validation studies performed on Clouds and the Earth's Radiant Energy system (CERES) instrument sensors aboard EOS Terra and Aqua spacecraft

Susan Thomas, K. Priestley, R. Wilson, D. Walikainen, G. Matthews

Proceedings Volume 6296, 62960L (2006) https://doi.org/10.1117/12.681626

KEYWORDS: Sensors, Shortwaves, Calibration, Space operations, Clouds, Sensor calibration, Black bodies, Diffusers, Lamps, Mirrors

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Proceedings Article | 30 December 2004 Paper

On-orbit characterizations of Earth Radiation Budget Experiment broadband shortwave active cavity radiometer sensor responses

Robert Lee, Robert Wilson, G. Louis Smith, Kathryn Bush, Susan Thomas, Dhirendra Pandey, Jack Paden

Proceedings Volume 5660, (2004) https://doi.org/10.1117/12.578822

KEYWORDS: Sensors, Shortwaves, Radiometry, Calibration, Solar radiation, Active sensors, Satellites, Quartz, Space operations, Remote sensing

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Proceedings Article | 4 November 2004 Paper

Validation of spacecraft active cavity radiometer total solar irradiance (TSI): long-term measurement trends using proxy TSI least squares analyses

Robert Lee, Robert Wilson

Proceedings Volume 5570, (2004) https://doi.org/10.1117/12.565647

KEYWORDS: Space operations, Magnetism, Radiometry, Sensors, Solar radiation, Climatology, Satellites, Climate change, Solar energy, Atmospheric sciences

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Proceedings Article | 24 February 2004 Paper

Calibrations of the Clouds and the Earth’s Radiant Energy System (CERES) instruments on the Terra and Aqua spacecrafts

Aiman Alhajjah, Dhirendra Pandey, Jack Paden, Kory Priestley, Robert Lee, Robert Wilson, Susan Thomas

Proceedings Volume 5232, (2004) https://doi.org/10.1117/12.511527

KEYWORDS: Calibration, Shortwaves, Sensors, Space operations, Lamps, Photodiodes, Black bodies, Silicon, Instrument modeling, Data modeling

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Proceedings Article | 16 February 2004 Paper

Twelve-month running trends from Earth Radiation Budget Satellite (ERBS) active-cavity radiometric measurements and global surface temperatures

Dhirendra Pandey, Robert Lee, Jack Paden, Kathryn Bush, Dianne Snyder, Robert Wilson, Waldena Banks, Aiman Al-Hajjah, Susan Thomas

Proceedings Volume 5235, (2004) https://doi.org/10.1117/12.511231

KEYWORDS: Satellites, Radiometry, Shortwaves, Sensors, Data centers, Temperature metrology, Calibration, Climatology, Climate change, Space operations

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Proceedings Article | 2 February 2004 Paper

On-orbit calibrations of the ERBE active-cavity radiometers on the Earth Radiation Budget Satellite (ERBS): 1984-2002

Robert Lee, George Smith, Kathryn Bush, Jack Paden, Dhirendra Pandey, Robert Wilson, Kory Priestley

Proceedings Volume 5234, (2004) https://doi.org/10.1117/12.511181

KEYWORDS: Calibration, Satellites, Space operations, Radiometry, Black bodies, Shortwaves, Solar radiation, Sensors, Sun, Bolometers

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Proceedings Article | 10 November 2003 Paper

On-orbit solar calibrations using the Aqua Clouds and Earth's Radiant Energy System (CERES) in-flight calibration system

Robert Wilson, Robert Lee, Jack Paden, Dhirendra Pandey, Kory Priestley, Susan Thomas, Aiman Al-Hajjah

Proceedings Volume 5151, (2003) https://doi.org/10.1117/12.507526

KEYWORDS: Calibration, Sensors, Shortwaves, Solar energy, Sun, Bolometers, Diffusers, Space operations, Radiometry, Solar radiation

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Proceedings Article | 10 November 2003 Paper

A comprehensive radiometric validation protocol for CERES Earth Radiation Budget climate record sensors

Kory Priestley, Susan Thomas, Peter Spence, Z. Szewczyk, Edward Kizer, Dale Walikainen, Aiman Al-Hajjah, Robert Wilson

Proceedings Volume 5151, (2003) https://doi.org/10.1117/12.507520

KEYWORDS: Calibration, Sensors, Optical filters, Shortwaves, Clouds, Space operations, Instrument modeling, Environmental sensing, Climatology, Error analysis

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Proceedings Article | 10 November 2003 Paper

Measurements of filtered lunar radiances using the NASA Terra spacecraft/CERES thermistor bolometer sensors during 2000 and 2001

Robert Lee, George Smith, Zbigniew Szewczyk, David Kratz, Kory Priestley, Susan Thomas, Kathryn Bush, Jack Paden, Dhirendra Pandey, Robert Wilson, Aiman Al-Hajjah

Proceedings Volume 5151, (2003) https://doi.org/10.1117/12.508333

KEYWORDS: Sensors, Shortwaves, Bolometers, Space operations, Calibration, Temperature metrology, Solids, Black bodies, Clouds, Instrument modeling

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Studies were conducted to define lunar radiances on an absolute radiometric scale tied to the International Temperature Scale of 1990 (ITS-90). The Clouds and the Earth's Radiant Energy System (CERES) thermistor bolometer sensor instruments were used to measure lunar radiances from the NASA Tropical Rainfall Measuring Mission (TRMM), Terra, and Aqua spacecraft platforms. Each CERES instrument package consisted of three different sensors: (1) broadband shortwave [0.3 to 5 micrometers]; (2) broadband total [0.3 to >100 micrometers]; and (3) narrowband, water vapor window [8 to 12 micrometers]. Moon-reflected solar radiances were measured with the shortwave sensor while both moon-reflected solar and moon-emitted longwave radiances were measured using the total sensor. The differences between the total and shortwave sensor measurements were used to determine the broadband longwave, moon-emitted radiances. The narrowband, water vapor window sensor measured only the longwave, moon-emitted radiances. The radiances were obtained as a function of phase angle (formed at the moon between directions to the sun and the spacecraft). The resulting filtered radiances were normalized to the mean sun-moon distance, one astronomical unit (AU), and to the mean earth-moon distance of 0.0026 AU (384,400 kilometers). 1998, 2000, and 2001, CERES lunar filtered measurements are presented, compared, and analyzed. Additional measurements are presented from the January 9, 2001, and May 16, 2003, total lunar eclipse events. Analyses of the Clouds and the Earth's Radiant Energy System (CERES) thermistor bolometer sensor observations of lunar radiances indicated that broadband shortwave and longwave lunar filtered radiances can be linked to a radiometric scale based upon an International Temperature Scale of 1990 (ITS-90) at absolute levels approaching ± 0.2 Wm^-2sr^-1. For a lunar image diameter of 31 minutes of arc, an emitting lunar disc temperature of approximately 400 Kelvin was estimated from the longwave radiances near 7-degree phase angle. The integration of the CERES unfiltered radiances over all reflection angles can be used to define the moon radiation budget (MRB).

Proceedings Article | 14 March 2003 Paper

Performance studies of CERES sensors on Earth Science Enterprise (ESE) Terra mission using onboard calibrations and other validation methods

Susan Thomas, Kory Priestley, Robert Lee, Peter Spence, Robert Wilson, Aiman Al-Hajjah, Jack Paden, Dhirendra Pandey

Proceedings Volume 4886, (2003) https://doi.org/10.1117/12.462968

KEYWORDS: Sensors, Shortwaves, Calibration, Black bodies, Mirrors, Bolometers, Space operations, Sensor calibration, Diffusers, Space telescopes

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Clouds and the Earth's Radiant Energy system (CERES) sensors provide accurate measurements for the long-term monitoring of the Earth's radiation budget components such as reflected shortwave and emitted longwave radiances. CERES instruments has three scanning thermistor bolometers that measure broadband radiances in the shortwave (0.3 to 5.0 micrometer), total (0.3 to >100 micrometer) and in 8 - 12 micrometer water vapor window regions. Two of the CERES instruments (Flight Models 1 and 2(FM1&2)) are part of ESE Terra mission and has been successfully making Earth radiance measurements for the past two years. The CERES sensors are calibrated in flight using the on-board blackbody sources and a tungsten lamp known as internal calibration module (ICM) as well as a solar diffuser plate known as the Mirror Attenuator Mosaic (MAM). The ICM calibrations is used to determine the sensor measurement precisions during the ground, ground to orbit, and the on-orbit phases of the sensor calibrations. The MAM calibrations define on-orbit shifts or drifts in shortwave and total sensor responses. The traditional validation studies conducted to understand the stability of the sensors' performance include the analysis of Tropical Mean (TM) value using nadir tropical ocean measurements and three channel intercomparison between sensors of the same instrument. With two CERES instruments on the same platform, an additional study utilizing direct comparison of similar sensor measurements viewing the same geolocation is also conducted. The ICM results have shown that total sensors on both instruments have shown a variation of 0.25 and 0.5 percent respectively, whereas the shortwave sensors show a minimal change of 0.2 percent each. With high variability during the initial year, the MAM results have stabilised within the 0.5 percent precision range in the second year. The validation studies have shed additional light into the behaviour of total sensors in the shortwave and longwave spectral regions. The TM longwave day night difference (DN) derived from longwave sensors of each CERES instrument indicate that the FM1 sensors have varied about 0.25 watts m^-2sr^-1, whereas the total sensor in FM2 has a gradual rise of 1.4 watts m^-2sr^-1 in a 30 month period. This paper discusses briefly the contribution of each calibration and validation study in understanding the CERES sensors' behavior and the results from both Terra instruments' sensors. It also discusses how the various analyses are put together in understanding the rise seen in the total sensor of FM2 instrument.

Proceedings Article | 24 September 2002 Paper

On-orbit radiometric calibrations of the Earth Radiation Budget Experiment (ERBE) active-cavity radiometers on the Earth Radiation Budget Satellite (ERBS)

Robert Lee, Jack Paden, Dhirendra Pandey, Robert Wilson, Kathryn Bush, G. Louis Smith

Proceedings Volume 4814, (2002) https://doi.org/10.1117/12.451614

KEYWORDS: Sensors, Radiometry, Space operations, Calibration, Satellites, Shortwaves, Black bodies, Solar radiation, Resistance, Lamps

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Proceedings Article | 21 February 2001 Paper

Relationship between the Clouds and the Earth's Radiant Energy System (CERES) measurements and surface temperatures of selected ocean regions

Dhirendra Pandey, Robert Lee, Shannon Brown, Jack Paden, Peter Spence, Susan Thomas, Robert Wilson, Aiman Al-Hajjah

Proceedings Volume 4150, (2001) https://doi.org/10.1117/12.416957

KEYWORDS: Optical filters, Shortwaves, Satellites, Clouds, Temperature metrology, Sensors, Calibration, Bolometers, Sensor calibration, Space telescopes

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Proceedings Article | 31 January 2001 Paper

Validation and analysis of Earth Radiation Budget active-cavity radiometric data (1985-1999)

Jack Paden, G. Louis Smith, Robert Lee, Kory Priestley, Dhirendra Pandey, Robert Wilson

Proceedings Volume 4168, (2001) https://doi.org/10.1117/12.413852

KEYWORDS: Sensors, Shortwaves, Calibration, Data acquisition, Radiometry, Sun, Black bodies, Satellites, Temperature metrology, Climatology

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Proceedings Article | 15 November 2000 Paper

Determination and validation of slow mode coefficients of the Clouds and the Earth's Radiant Energy System (CERES) scanning thermistor bolometers

G. Louis Smith, Dhirendra Pandey, Peter Spence, Kory Priestley, Bruce Barkstrom, Robert Lee, Jack Paden, Susan Thomas, Robert Wilson, Aiman Al-Hajjah

Proceedings Volume 4135, (2000) https://doi.org/10.1117/12.494226

KEYWORDS: Sensors, Calibration, Shortwaves, Bolometers, Black bodies, Space operations, Clouds, Instrument modeling, Aerospace engineering, Fermium

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Proceedings Article | 15 November 2000 Paper

On-orbit solar calibrations using the Terra Clouds and Earth's Radiant Energy System (CERES) in-flight calibration system

Robert Wilson, Robert Lee, Bruce Barkstrom, Jack Paden, Dhirendra Pandey, Kory Priestley, G. Louis Smith, Susan Thomas, Aiman Al-Hajjah

Proceedings Volume 4135, (2000) https://doi.org/10.1117/12.494223

KEYWORDS: Calibration, Shortwaves, Sensors, Sun, Radiometry, Solar energy, Bolometers, Diffusers, Space operations, Solar radiation

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Proceedings Article | 15 November 2000 Paper

Terra spacecraft CERES flight model 1 and 2 sensor measurement precisions: ground-to-flight determinations

Robert Lee, Kory Priestley, Bruce Barkstrom, Susan Thomas, Aiman Al-Hajjah, Jack Paden, Dhirendra Pandey, Robert Wilson, G. Louis Smith

Proceedings Volume 4135, (2000) https://doi.org/10.1117/12.494216

KEYWORDS: Sensors, Calibration, Shortwaves, Black bodies, Lamps, Space operations, Environmental sensing, Sensor calibration, Chlorine, Photodiodes

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Proceedings Article | 15 November 2000 Paper

Clouds and the Earth's Radiant Energy System (CERES) spectral response characterizations

Aiman Al-Hajjah, Kory Priestley, Susan Thomas, Robert Lee, Bruce Barkstrom, Jack Paden, Dhirendra Pandey, Robert Wilson

Proceedings Volume 4135, (2000) https://doi.org/10.1117/12.494240

KEYWORDS: Sensors, Shortwaves, Fourier transforms, Calibration, Optical filters, Mirrors, Reflectivity, Clouds, Signal detection, Planets

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Proceedings Article | 17 July 2000 Paper

Early trends of the Clouds and the Earth's Radiant Energy System (CERES) instrument's performance using in-flight calibration sources for the Earth Science Enterprise (ESE) TERRA mission

Susan Thomas, Robert Lee, Kory Priestley, Bruce Barkstrom, Aiman Al-Hajjah, Robert Wilson, Jack Paden, Dhirendra Pandey

Proceedings Volume 4030, (2000) https://doi.org/10.1117/12.391785

KEYWORDS: Calibration, Sensors, Black bodies, Shortwaves, Bolometers, Space operations, Sensor calibration, Lamps, Clouds, Earth sciences

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Proceedings Article | 28 December 1999 Paper

Ground through on-orbit transfer of the International Temperature Scale of 1990 (ITS-90): radiometeric scale using the CERES thermistor bolometers and built-in flight calibration systems

Robert Lee, Susan Thomas, Robert Wilson, Kory Priestley, Jack Paden, Dhirendra Pandey, Aiman Al-Hajjah

Proceedings Volume 3870, (1999) https://doi.org/10.1117/12.373207

KEYWORDS: Sensors, Calibration, Black bodies, Shortwaves, Bolometers, Lamps, Space operations, Sensor calibration, Tungsten, Aluminum

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The Clouds and Earth's Radiant Energy System (CERES thermistor bolometers were calibrated using filtered radiances, characterized on an International Temperature Scale of 1990 (ITS-90) derived absolute radiometric scale. Longwave filtered radiances were characterized using the optical and geometric surface properties of the reference Narrow-Field-of-View Blackbody (NFBB), the NFBB temperature measurements from the ITS-90 calibrated platinum resistance thermometers (PRT) embedded in the blackbodies, and the spectral responses of the CERES bolometers. Shortwave filtered radiances were characterized using the cryogenically-cooled Transfer Active Cavity Radiometer (TACR) which was an ITS-90 transfer standard, and using the spectral responses of the bolometers. In ground vacuum facilities, the ITS-90, temperature-based radiometric scale was transferred to the CERES bolometers. As ITS-90 transfer standards, the bolometers were used to characterize the emitted filtered radiances from in-flight systems: (1) the internal calibration module (ICM) which consisted of anodized aluminum blackbodies and tungsten lamp sources; and (2) mirror attenuator mosaic (MAM) which was an aluminum solar diffuser plate, built into the bolometer instrumentation. From the ground [October 1995] through the on-orbit phases [December 1998 - July 1999] of the Tropical Rainfall Measuring Mission (TRMM) Spacecraft CERES instrument mission, the stabilities of the bolometer's responses were assessed from periodical observations of the in-flight calibration systems radiances. Each CERES instrument package consisted of broadband shortwave [0.3 micrometer to 5.0 micrometer], broadband total [0.3 micrometer to greater than 100 micrometer], and narrowband window [8 micrometer and 12 micrometer], scanning thermistor bolometer sensor units; and of in-flight calibration systems. Between the ground and initial on-orbit calibrations, the TRMM CERES bolometers and the built-in, flight calibration system sources maintained their filtered radiance measurement ties to ITS-90 at the plus or minus 0.2 Wm^-2sr^-1 precision level. On-orbit calibration studies indicate that the radiance measurements were stable at the plus or minus 0.2 Wm^-2sr^-1 precision level. The ground and on- orbit calibration results are presented and discussed.

Proceedings Article | 24 September 1999 Paper

Analyses of on-orbit determinations of the Clouds and the Earth's Radiant Energy System (CERES) thermistor bolometer sensor zero-radiance offsets

Robert Lee, Susan Thomas, Kory Priestley, Bruce Barkstrom, Jack Paden, Dhirendra Pandey, G. Louis Smith, Aiman Al-Hajjah, Robert Wilson

Proceedings Volume 3750, (1999) https://doi.org/10.1117/12.363545

KEYWORDS: Sensors, Space operations, Content addressable memory, Shortwaves, Bolometers, Clouds, Solar energy, Black bodies, Calibration, Instrument modeling

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Proceedings Article | 24 September 1999 Paper

Point response characteristics for the CERES/EOS-PM, FM3, and FM4 instruments

Jack Paden, G. Louis Smith, Robert Lee, Dhirendra Pandey, Kory Priestley, Susan Thomas, Robert Wilson

Proceedings Volume 3750, (1999) https://doi.org/10.1117/12.363536

KEYWORDS: Point spread functions, Instrument modeling, Data modeling, Shortwaves, Calibration, Data acquisition, Sensors, Radiometry, Phase modulation, Fermium

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