SMOS salinity retrievals enhancement in coastal areas by joint application of nodal sampling and corrected correlator efficiency

This work is focused on the quality improvement of ESA's SMOS (Soil Moisture and Ocean Salinity) salinity retrievals, paying special attention to coastal regions. Two correction techniques have been applied to enhance the quality of brightness temperatures: the nodal sampling for the reduction of Gibbs-like contamination and the correction of residual amplitude calibration errors for the mitigation of systematic biases close to land. The application of these techniques leads to improvements in salinity retrievals not only in open ocean, but also in strongly contaminated coastal areas. Comparisons to in-situ salinity estimates show that salinities retrieved from the corrected brightness temperatures are closer to zero bias and present a reduced standard deviation with respect to those retrievals from the current SMOS brightness temperatures.