Comparison of Msg/seviri Calibration Reference with Meris Brf over Bright Desert Calibration Targets

Meteosat Second Generation (MSG) is the new generation of European geostationary meteorological satellites operated at EUMETSAT. SEVIRI, the MSG main radiometer, measures the reflected solar radiation within three spectral bands centered at 0.6, 0.8 and 1.6 m, and within a broad band similar to the VIS channel of MVIRI, the radiometer on-board the first generation of METEOSAT satellites. The operational calibration of these channels relies on modelled reflectances over bright desert sites, as no in-flight calibration device is available. These simulated reflectances represent therefore the “reference” against which SEVIRI is calibrated. The present study evaluates the uncertainties associated with the characterization of this “reference”, i.e., the modelled reflectances. To this end, top-of-atmosphere simulated reflectances are compared with calibrated space-borne observations acquired over the SEVIRI desert calibration sites. Results show that the relative bias between simulation and observation does not exceed 6%.