The CERES spacecraft scanning thermistor bolometers measure earth-reflected solar and earth-emitted longwave radiances, at the top-of-the-atmosphere. The bolometers measure the earth radiance in the broadband shortwave solar and total spectral bands as well as in the 8-12 micrometers water vapor window spectral band over geographical footprints as small as 10 kilometers at nadir. November 1997, the first set of CERES bolometers was launched on the Tropical Rainfall Measuring Mission spacecraft. Ground vacuum calibrations define the initial count conversion coefficients that are used to convert the bolometer output voltages into filtered earth radiances. The mirror attenuator mosaic (MAM), a solar diffuser plate, was built into the CERES instrument package calibration using the solar radiances reflected from the MAM's. Each MAM consists of baffle-solar diffuser plate system, which guide incoming solar radiances into the instrument fields of view of the shortwave and total wave sensor units. The MAM diffuser reflecting type surface consists of an array of spherical, overcoated with silicon dioxide. Thermistors are located in each MAM plate and baffle. The CERES MAM is designed to yield calibration precisions approaching 2 percent for the total and shortwave detectors. In this paper, the MAM solar calibration data reduction techniques are presented along with on-orbit measurements.
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