A comparison of multi-polarization and multi-angular approaches for estimating bare soil surface roughness from spaceborne radar data

Soil surface roughness and moisture content both have a significant effect on microwave backscatter to the satellite. The purpose of this work is to evaluate the optimum sensor configuration for existing radar satellites to quantify soil surface roughness. A simulation study using theoretical and empirical models permits the estimation of the sensitivity of the backscatter coefficient to relative variations in soil parameters in terms of radar characteristics. Two different configurations for estimating surface roughness were tested, multi-polarization (co-polarizations) and multi-angular, and the results of the multi-angular configuration provided the best results. A normalized radar backscatter soil roughness index (NBRI) is presented for estimating soil roughness from a multi-angular approach using sensors such as RADARSAT-1. This index was tested using the geometric optics model (GOM) and RADARSAT data. Coefficients of determination of 99% and 83%, respectively, were obtained for each simulation.