ELECTROMAGNETIC-WAVE SCATTERING FROM REAL-LIFE ROUGH-SURFACE PROFILESAND PROFILES BASED ON AN AVERAGED SPECTRUM

We investigate random rough-surface scattering with surface profiles o f three different kinds. For each surface profile we calculate the sca ttering cross section exactly, and the average scattering cross sectio n is taken over realizations. In the first method we use a limited num ber of real-life measured profiles of natural surfaces. In the second method, the average surface spectrum of the measured profiles of the f irst method is found. With the use of the averaged spectrum, many prof iles are generated, the scattering cross sections of which are calcula ted. In the third method, the averaged rough-surface power spectral de nsity found in the second method is fitted with a spectrum (e.g., powe r law). From the fitted spectrum, many profiles are generated and the average scattering cross section is calculated. We find that the back- scattering levels of Method 3 and Method 1 can have differences (e.g, 6 dB). Method 2 generally gives reasonable results within 1.1 dB of Me thod 1. Examples are taken from soil, snow, and rock surfaces. (C) 199 6 John Wiley & Sons, Inc.