Seven CERES instruments on five satellites have been launched. Six of the seven are currently operational. The instruments measure reflected sunlight and thermal radiation emitted by the Earth. CERES helps provide measurements of the spatial and temporal distribution of Earth’s Radiation Budget (ERB) components. This further develops understanding of the links between the ERB and the proprieties of atmosphere and surface that define it.
Each CERES instrument is a narrow field-of-view scanning radiometer with nadir footprint size of 10 km (TRMM), 20 km (Terra, Aqua), or 24 km (S-NPP, NOAA-20). A narrow FOV enables: higher spatial resolution, clear-sky observations for cloud feedback studies, frequent space views to correct thermal offsets, intercalibration with other instruments, and lunar/solar calibrations.
CERES Proto-Flight Model (PFM), the first CERES instrument, was launched aboard the Tropical Rainfall Measuring Mission (TRMM) on November 28, 1997. The last data processed from the PFM instrument aboard TRMM was March 2000.
CERES-FM1 and CERES-FM2 were launched on December 18, 1999, aboard the Terra platform. One operates in a cross-track scan mode and the other in a biaxial scan mode. The cross-track scanning data extends the CERES data from the the CERES-PFM to achieve complete global measurements by adding mid-latitude and polar observations. The biaxial scan mode provides new observations of the angular radiation fields in order to improve the accuracy of the final fluxes of solar and thermal energy used to derive the Earth’s radiation balance.
CERES-FM3 and CERES-FM4 were launched on May 4, 2002, aboard the Aqua platform. Until June 2005, one instrument on each platform operated in a fixed azimuth scanning mode and the other operated in a rotating azimuth scanning mode; now all are typically operating in the fixed azimuth scanning mode.
CERES-FM5 was launched on October 28, 2011, aboard the Suomi-NPP platform. The CERES-FM5 instrument operates in the fixed azimuth scanning mode though it can operate in a rotating azimuth scanning mode.
CERES-FM6 was launched on November 18, 2018, aboard the NOAA-20 (JPSS-1) platform.