Uncertainty of Radar Backscattering Coefficients from Bare Soil Surface Due to Roughness Sample Variances

In this study, we examine how the surface roughness uncertainty, arising from sample variance, propagates to radar backscattering coefficients from exponentially correlated bare soil surfaces. We quantify the uncertainty of backscattering coefficients as a function of surface size, considering different slope indexes (the ratio of RMS height to correlation length) and roughness parameters. Furthermore, we infer a generalized rule of minimum surface size required to contain the uncertainty within 0.6dB, 1.0dB, and 1.5dB, accounting for commonly used incidence (20degrees to 60degrees) and frequency in L-band (1.25GHz). The findings could offer insights into optimal surface size selection for estimating radar backscattering coefficients from bare soil surfaces.