Evaluating the Radiometric Performance of the Clouds and the Earth’s Radiant Energy System (CERES) Instruments on Terra and Aqua Over 20 Years

Six Clouds and the Earth’s Radiant Energy System (CERES) instruments on four satellites are used to produce a global continuous multidecadal record of Earth’s radiation budget (ERB) at the top-of-atmosphere (TOA). Each CERES instrument was calibrated and characterized on the ground before launch, while postlaunch calibration was conducted using onboard calibration sources. The performance of the CERES instruments is verified using vicarious approaches involving both Earth and celestial targets. In this article, we describe the calibration and validation approach and demonstrate the performance of the CERES instruments on the Terra and Aqua spacecraft over the 20-year period since launch. Validation results demonstrate that after applying the appropriate calibration corrections, all four instruments are stable and perform consistently with each other. Comparisons of observations between instruments on the two spacecraft during orbital crossings further confirm the consistent performance across all instruments over the 20-year period.