The Clouds and the Earth's Radiant Energy System (CERES) instrument is a narrow field-of-view scanning radiometer that measures reflected solar and emitted thermal infrared radiation from Earth. These data provide a better understanding of the energy exchange between Earth and space that drives Earth’s climate system and how this energy exchange changes over time.

The first CERES instrument was launched aboard the joint NASA/Japan Aerospace Exploration Agency Tropical Rainfall Measuring Mission (TRMM), which operated from 1997 to 2015. Six CERES instruments are currently in space, including the CERES Flight Model 2 (FM2), which was launched on the Terra satellite in December 1999.