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15 November 2000 Terra spacecraft CERES flight model 1 and 2 sensor measurement precisions: ground-to-flight determinations
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On December 18, 1999, the Clouds and the Earth’s Radiant Energy System (CERES) flight models 1 (FM1) and 2 (FM2) sets of scanning thermistor bolometer sensors were launched into orbit aboard the NASA Terra Spacecraft. The sensors measure earth radiances in the broadband shortwave solar (0.3 µm - 5.0 µm) and total (0.3 µm - >100 µm) spectral bands, as well as in the 8 -12 micrometer water vapor window, narrow-band spectral band. In order to measure sensor response drifts or shifts, inflight blackbody and evacuated tungsten lamp calibration systems were built into the CERES instrumentation. These systems were used to determine the sensor responses during the ground/pre-launch, ground to orbit, and on-orbit phases of the sensor calibrations. Analyses of the pre-launch, vacuum ground calibrations indicated that the CERES sensor responses can change as much as 0.6% between vacuum and ground ambient atmospheric pressure environments. The sensor responses were found to vary directly with the temperature as much as 2% between the 311 K and 270 K thermal environment of the vacuum calibration facility. From the vacuum ground calibration through the on-orbit calibration phases, the Terra Spacecraft CERES broadband total and shortwave sensor responses and in-flight calibration sources maintained their radiance measurement ties to an International Temperature Scale of 1990 (ITS-90) radiometric scale at precision levels approaching ± 0.3% (0.3 Wm-2sr-1). Analyses of the ground and on-orbit calibrations are presented and discussed using built-in, reference blackbody and lamp observations.
© (2000) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Robert Benjamin Lee III, Kory J. Priestley, Bruce R. Barkstrom, Susan Thomas, Aiman Al-Hajjah, Jack Paden, Dhirendra K. Pandey, Robert S. Wilson, and G. Louis Smith "Terra spacecraft CERES flight model 1 and 2 sensor measurement precisions: ground-to-flight determinations", Proc. SPIE 4135, Earth Observing Systems V, (15 November 2000);

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