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

Abstract

The CERES instruments obtain their measurements by three scanning thermistor bolometers: total channel which measures radiation in the 0.3 - 100 μm spectral region; window channel which measures radiations from 8 - 12 μm; and the shortwave channel which measures the reflected solar energy from 0.3 - 5.0 μm. The Aqua dedicated to advancing our understanding of Earth's water cycle and our environment was launched on May 4, 2002. The Aqua CERES Internal Calibration module follows similar operations as previous CERES instruments (FM1 and FM2) that were launched on the Terra spacecraft in December 1999. The Internal Calibration mechanism and the resulting data for Flight Model 3 (FM3) and Flight Model 4 (FM4) instruments are critical in determining the stability of both instruments as referenced to ground-based calibration. In this paper, the Internal Calibration procedure and the results will be presented. Both the FM3 and FM4 instruments were found stable within 0.3% since the launch date. Results for the FM1 and FM2 instruments will also be discussed.