The European Space Agency Soil Moisture and
Ocean Salinity (SMOS) mission aims at obtaining global maps of
soil moisture and sea surface salinity from space for large-scale and
climatic studies. It uses an L-band (1400–1427 MHz) Microwave
Interferometric Radiometer by Aperture Synthesis to measure
brightness temperature of the earth’s surface at horizontal and
vertical polarizations ( h and v). These two parameters will be
used together to retrieve the geophysical parameters. The retrieval
of salinity is a complex process that requires the knowledge of
other environmental information and an accurate processing of
the radiometer measurements. Here, we present recent results
obtained from several studies and field experiments that were part
of the SMOS mission, and highlight the issues still to be solved
