The Clouds and the Earth's Radiant Energy System (CERES) scanner 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 scanner, CERES Prototype Flight Model (PFM), was launched aboard the joint NASA/Japan Aerospace Exploration Agency Tropical Rainfall Measuring Mission (TRMM) satellite in November 1997, and was operational through 2015.