An empirical model for phase difference statistics of rough surfaces

Polarimetric radar measurements were conducted for bare soil surfaces under a variety of roughness and moisture conditions at 1.5, 4.75, and 9.5 GHz at incidence angles ranging from 20° to 70°. Using a laser profile meter and dielectric probes, complete and accurate sets of ground truth data were collected for each surface condition from which accurate measurement were made of the rms height, correlation length, and dielectric constant. Based on the experimental observations, an empirical model is developed for the degree of correlation, which is a measure of the width of the probability density function of the co-polarized phase angle φ_c(=φ_hh-φ_υυ) for a distributed target. The validity of the proposed model is checked by comparing the results based on the empirical model with an independent data set measured by a different radar system