Temporal and spatial variabilities of surface roughness response over Hapex-Sahel area: use of ERS1 windscatterometer

Surface roughness and vegetation reduce the variations of σ ⁰ with angle and the sensitivity of the signal to soil moisture. Without any knowledge of one of these parameters, it is difficult to discriminate their effect. In this study, taking into account the temporal and angular evolutions of the soil moisture sensitivity, the soil-moisture content is extracted. After reducing the angular effects, the authors removed soil moisture influence on σ ⁰(dB). The remaining signal is thus linked to vegetation and soil roughness. Without any roughness measurement, the possibility to take into account surface roughness variability into signal evolution is addressed