Pre-launch characterization of spectral response functions for the Clouds and Earth's Radiant Energy System (CERES) instrument sensors

Abstract The method used to estimate the unfiltered shortwave broadband radiance from the filtered radiances measured by the Geostationary Earth Radiation Budget (GERB) instrument is presented. This unfiltering method is used to generate the first released edition of the GERB-2 dataset. The method involves a set of regressions between the unfiltering factor (i.e., the ratio of the unfiltered and filtered broadband radiances) and the narrowband observations of the Spinning Enhanced Visible and Infrared Imager (SEVIRI) instrument. The regressions are theoretically derived from a large database of simulated spectral radiance curves obtained by radiative transfer computations. The generation of the database is fully described. Different sources of error that may affect the GERB unfiltering have been identified and the associated error magnitudes are assessed on this database. For most of the earth–atmosphere conditions, the error introduced during the unfiltering process is below 1%. In some conditions (e.g., low sun elevation above the horizon) the error can present a higher relative value, but the absolute error value remains well under the accuracy goal of 1% of the full instrument scale (2.4 W m−2 sr−1). To increase the confidence level, the edition 1 unfiltered radiances of GERB-2 are validated by cross comparison with collocated and coangular Clouds and the Earth’s Radiant Energy System (CERES) observations for different scene types. In addition to an overall offset between the two instruments, the intercomparisons indicate a scene-type dependency up to 4% in unfiltered radiance. Further studies are required to confirm the cause, but an insufficiently accurate characterization of the shortwave spectral response of the GERB instrument in the visible part of the spectrum is one area under further investigation.

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Generation of a Seamless Earth Radiation Budget Climate Data Record: A New Methodology for Placing Overlapping Satellite Instruments on the Same Radiometric Scale

Remote Sensing ◽

10.3390/rs12172787 ◽

2020 ◽

Vol 12 (17) ◽

pp. 2787

Author(s):

Mohan Shankar ◽

Wenying Su ◽

Natividad Manalo-Smith ◽

Norman G. Loeb

Keyword(s):

Spectral Response ◽

Radiant Energy ◽

Energy System ◽

Radiation Budget ◽

Climate Data ◽

Data Record ◽

Earth Radiation Budget ◽

Climate Data Record ◽

Earth Radiation

The Clouds and the Earth’s Radiant Energy System (CERES) instruments have enabled the generation of a multi-decadal Earth radiation budget (ERB) climate data record (CDR) at the top of the Earth’s atmosphere, within the atmosphere, and at the Earth’s surface. Six CERES instruments have been launched over the course of twenty years, starting in 1999. To seamlessly continue the data record into the future, there is a need to radiometrically scale observations from newly launched instruments to observations from the existing data record. In this work, we describe a methodology to place the CERES Flight Model (FM) 5 instrument on the Suomi National Polar-orbiting Partnership (SNPP) spacecraft on the same radiometric scale as the FM3 instrument on the Aqua spacecraft. We determine the required magnitude of radiometric scaling by using spatially and temporally matched observations from these two instruments and describe the process to radiometrically scale SNPP/FM5 to Aqua/FM3 through the instrument spectral response functions. We also present validation results after application of this radiometric scaling and demonstrate the long-term consistency of the SNPP/FM5 record in comparison with the CERES instruments on Aqua and Terra.

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Validation of Point Spread Functions of CERES Radiometers by the Use of Lunar Observations

Journal of Atmospheric and Oceanic Technology ◽

10.1175/2010jtecha1322.1 ◽

2010 ◽

Vol 27 (6) ◽

pp. 1005-1011 ◽

Cited By ~ 8

Author(s):

Kory J. Priestley ◽

Susan Thomas ◽

G. Louis Smith

Keyword(s):

Radiant Energy ◽

High Sensitivity ◽

Energy System ◽

Response Functions ◽

The Moon ◽

Point Spread Functions ◽

Point Spread ◽

Lunar Observations ◽

Pointing Accuracy ◽

Raster Scans

Abstract The Clouds and the Earth’s Radiant Energy System (CERES) scanning radiometers have been operating to make raster scans of the moon on a quarterly basis to validate the point response function for the three channels of flight models 1–4 aboard the Terra and Aqua spacecraft. Instrument pointing accuracy was verified by this method to 0.2° for the total channel of FM-3. The point response functions were computed from the lunar observations and were found to be nominal with the exception of the FM-2 window channel, which was found to have a region of high sensitivity. This anomaly is attributed to a delamination of the detector flake from the heat sink in that region. The influence of this anomaly is accounted for by the in-flight calibration and has no adverse effect on the application of the data.

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

10.1117/12.494240 ◽

2000 ◽

Author(s):

Aiman Al-Hajjah ◽

Kory J. Priestley ◽

Susan Thomas ◽

Robert B. Lee III ◽

Bruce R. Barkstrom ◽

...

Keyword(s):

Spectral Response ◽

Radiant Energy ◽

Energy System

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End-to-end spectral characterization of the Clouds and the Earth's Radiant Energy System (CERES) thermistor bolometer radiometers

10.1117/12.333629 ◽

1998 ◽

Cited By ~ 2

Author(s):

Kory J. Priestley ◽

Bruce R. Barkstrom ◽

Herbert C. Bitting ◽

Robert B. Lee III ◽

Dhirendra K. Pandey ◽

...

Keyword(s):

Radiant Energy ◽

Energy System ◽

Spectral Characterization ◽

End To End

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Pre-launch characterization of the clouds and the Earth'S Radiant Energy System (CERES) flight model 5 (FM5) instrument on NPP

2011 IEEE International Geoscience and Remote Sensing Symposium ◽

10.1109/igarss.2011.6048891 ◽

2011 ◽

Cited By ~ 1

Author(s):

Susan Thomas ◽

Kory J. Priestley ◽

Mohan Shankar ◽

Nathaniel P. Smith ◽

Mark G. Timcoe

Keyword(s):

Radiant Energy ◽

Energy System ◽

Flight Model

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Evaluation of net shortwave radiation over China with a regional climate model

Climate Research ◽

10.3354/cr01598 ◽

2020 ◽

Vol 80 (2) ◽

pp. 147-163

Author(s):

X Liu ◽

Y Kang ◽

Q Liu ◽

Z Guo ◽

Y Chen ◽

...

Keyword(s):

Regional Climate Model ◽

Climate Model ◽

Regional Climate ◽

Radiant Energy ◽

Energy System ◽

Radiation Budget ◽

Shortwave Radiation ◽

Monsoon Region ◽

Clear Sky ◽

Sky Conditions

The regional climate model RegCM version 4.6, developed by the European Centre for Medium-Range Weather Forecasts Reanalysis, was used to simulate the radiation budget over China. Clouds and the Earth’s Radiant Energy System (CERES) satellite data were utilized to evaluate the simulation results based on 4 radiative components: net shortwave (NSW) radiation at the surface of the earth and top of the atmosphere (TOA) under all-sky and clear-sky conditions. The performance of the model for low-value areas of NSW was superior to that for high-value areas. NSW at the surface and TOA under all-sky conditions was significantly underestimated; the spatial distribution of the bias was negative in the north and positive in the south, bounded by 25°N for the annual and seasonal averaged difference maps. Compared with the all-sky condition, the simulation effect under clear-sky conditions was significantly better, which indicates that the cloud fraction is the key factor affecting the accuracy of the simulation. In particular, the bias of the TOA NSW under the clear-sky condition was <±10 W m-2 in the eastern areas. The performance of the model was better over the eastern monsoon region in winter and autumn for surface NSW under clear-sky conditions, which may be related to different levels of air pollution during each season. Among the 3 areas, the regional average biases overall were largest (negative) over the Qinghai-Tibet alpine region and smallest over the eastern monsoon region.

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