Cloud and Earth Radiant Energy System (CERES)

P. G. Weber

Los Alamos National Laboratory

The instruments of the Cloud and Earth Radiant Energy System (CERES) are intended to provide the Earth Observing System (EOS) with continued long-term measurement of the Earth's radiation budget. The CERES instruments are a pair of broadband, scanning radiometers based on the Earth Radiation Budget Experiment (ERBE) scanners (EOS 1990, Stowe et al. 1990). There are three spectral channels in each radiometer: total radiance (0.2 to > 100 mm), shortwave (0.2 to 3.5 m) and longwave (6.5 to 25 m), defined using filters. The detectors are thermistor bolometers, which are to operate at a constant 375C. The operating principle is that of an active cavity radiometer; namely, the heat required to main-tain the temperature of the active cavity relative to a reference cavity determines the thermal flux collected. The instrument view angle is to be 82 (half angle) about nadir, while the instantaneous field-of-view (IFOV) will be about a 35 pixel centered at the optical axis corresponding to a 25 x 35-km footprint at nadir from a polar platform.