An Additive Mask Correction Approach for Reducing the Systematic Floor Error in Imaging Radiometry by Aperture Synthesis

The Soil Moisture and Ocean Salinity (SMOS) mis- sion is a European Space Agency (ESA) mission aimed at the global monitoring of surface soil moisture and ocean salinity from radiometric L-band observations. This work described in this letter is devoted to the reduction of the systematic error in the reconstruction of brightness temperature maps from SMOS interferometric measurements. Despite the fact that the image reconstruction method currently used was proposed and imple- mented in the ESA L1 processor for reducing this error, residual offset and ripples still persist. This is particularly penalizing for oceanographic applications with SMOS data. A new approach for reducing this residual error is presented here and illustrated with brightness temperature maps retrieved over the Pacific ocean. Index Terms—Aperture synthesis, imaging radiometry, inverse problem, reconstruction bias, regularization.