Surface Soil Moisture Retrieval from Envisat/asar Ap Observations Combining Two Backscattering Models

Radar based surface soil moisture retrieval has been subject of intense research during the last decades. However, the space-borne radar sensors available so far provided single configuration observations where the influence of surface roughness frequently caused the solution of the backscattering process to be ill-posed. The ENVISAT/ASAR sensor offers new perspectives since the alternating polarization (AP) mode acquires two simultaneous observations in different polarizations. However, the benefits of the AP mode for surface soil moisture retrieval are still unclear. In this paper a methodology proposed by Pauwels et al. [1] is adapted to ENVISAT/ASAR AP observations. The methodology combines two backscattering models and provides an estimation of the roughness and moisture of the soil surface. The results obtained show that the soil surface conditions and sensor configuration significantly affect the estimations, thus, the approach lacks robustness and cannot be generalized to any situation.