  SMOS (Soil Moisture and Ocean Salinity), is the second mission of 'Earth
Explorer' to be developed within the program 'Living Planet' of the European
Space Agency (ESA). This satellite, containing the very first 1.4GHz
interferometric radiometer 2D, will carry out the first cartography on a
planetary scale of the moisture of the grounds and the salinity of the oceans.
The forests are relatively opaque, and the knowledge of moisture remains
problematic. The effect of the vegetation can be corrected thanks a simple
radiative model. Nevertheless simulations show that the effect of the litter on
the emissivity of a system litter + ground is not negligible. Our objective is
to highlight the effects of this layer on the total multi layer system. This
will make it possible to lead to a simple analytical formulation of a model of
litter which can be integrated into the calculation algorithm of SMOS.
Radiometer measurements, coupled to dielectric characterizations of samples in
laboratory can enable us to characterize the geological structure. The goal of
this article is to present the step which we chose to validate this analytical
model.
