SMOS performance simulation analysis

In May 1999 the SMOS Earth Explorer mission was selected by ESA to provide global soil moisture and sea salinity maps. SMOS payload is MIRAS: an L-band 2D aperture synthesis interferometric radiometer, that generates brightness temperature images by processing the cross-correlations measured between the pairs of signals collected by each array element. In this paper we compare the results of the error budget used in previous SMOS studies to those obtained from a simulation campaign for different scenarios (brightness temperature input scenes). The total radiometric error, which includes the radiometric sensitivity term mainly due to the finite integration time, and the radiometric accuracy due to instrumental imperfections as well as residual calibration error, is computed from a series of 20 Monte Carlo simulations for each instrument configuration and scenario for both the brightness temperatures retrieved in the antenna reference frame (X- and Y-polarizations) and the Earth reference frame (V- and H- polarizations at each pixel). Finally, intercalibration instrumental drifts due to in-orbit temperature variations are analyzed using a standard configuration.