RADAR BACKSCATTER FROM A DENSE DISCRETE RANDOM MEDIUM

A dense medium phase matrix developed based on the concept of random l attice perturbation is employed in the radiative transfer theory to ca lculate the co- and cross-polarized backscatter from a layer of random ly distributed spherical scatterers. The position randomness propertie s are characterized by the variance and correlation function of scatte rer positions within the medium, The dense medium phase matrix differs from the conventional one in two major aspects, i.e., there is an amp litude and a phase correction, These corrections account for the effec ts of close spacing and position correlation between scatterers in a d ense discrete random medium. This study shows that phase coherency and close-spacing amplitude modifications are two separate corrections ne cessary for an electrically dense medium, Results indicate that there is a need to distinguish between spatially and electrically dense medi um, The phase correction is found to have a greater impact on cross-po larized than like-polarized backscatter coefficients; the converse is true of the amplitude correction, Backscattering calculations from the theory are compared with measurements from controlled microwave exper iments on random media consisting of closely packed spheres, and from field measurements of dry snowpack. Predictions from such a theory agr ee well with the measured data.