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 GIIz at incidence angles ranging from 20" to 70". Using a laser profile meter and dielectric prohes, a complete and accurate set of ground truth data were collected for each snrface conditions, from which accurate measurement were made of the rms height, correlation length, and dielectric constant. Rased on the experimental observations, an empirical model is developed for the degree of correlation a, which is a measure of the width of the probability density hinction of the co-polarized phase angle &(= mhh 4"") for a distributed target. The validity of the proposed model is checked by comparing t.he results based on the empirical model with an independent data set measured by a different radar system.