4.2. Oh model

The Oh model is established based on theoretical scattering models [9], scatterometer measurements, and airborne polarimetric SAR datasets (in L-, C-, and X-band, respectively) under different roughness and soil moisture conditions at incidence angles ranging from 10 to 70�. This model relates the co-polarized ratio <sup>p</sup> <sup>¼</sup> <sup>σ</sup><sup>0</sup> HH=σ<sup>0</sup> VV and the cross-polarized ratio <sup>q</sup> <sup>¼</sup> <sup>σ</sup><sup>0</sup> HV=σ<sup>0</sup> VV and absolute σ<sup>0</sup> HV to soil parameters (including s, l, ε) and radar system parameters (including the wave number k and local incidence angle θ).
