Soil moisture retrieval using the Danish L- & C-band polarimetric SAR

Danish polarimetric SAR data have been applied to estimate soil moisture (SM). The preliminary results evaluated with the L- and C-band SAR data acquired at the Danish test site Foulum during a number of missions in 1994 and 1995 are presented. In situ data have been collected during the SAR missions and the variations of SM at field scale are discussed. The Integral Equation Method (IEM), the Dubois empirical model and the Oh polarized-ratio model have been used as algorithms to inverse SM from polarimetric SAR data under near bare field conditions. Comparisons between the inversions and the in situ measured data showed that the Dubois empirical model gave the best results for inversion of SM. The standard deviations between the inversed and the measured data at C-band are s_m(v) = 6.1% for SM and s_σ = 0.37 cm for soil surface rms height, respectively. C-band data are better than L-band data for estimation of surface roughness.