Wavelength dependence in radiowave scattering and specularpoint theory.
Abstract
Radiowave scattering from natural surfaces contains a strong quasispecular component that at fixed wavelengths is consistent with specularpoint theory, but often has a strong wavelength dependence that is not predicted by physical optics calculations under the usual limitations of specularpoint models. Wavelength dependence can be introduced by a physical approximation that preserves the specularpoint assumptions with respect to the radii of curvature of a fictitious, effective scattering surface obtained by smoothing the actual surface. A uniform lowpass filter model of the scattering process yields explicit results for the effective surface roughness versus wavelength. Interpretation of experimental results from planetary surfaces indicates that the asymptotic surface height spectral densities fall at least as fast as an inverse cube of spatial frequency. Asymptotic spectral densities for Mars and portions of the lunar surface evidently decrease more rapidly.
 Publication:

Radio Science
 Pub Date:
 February 1976
 DOI:
 10.1029/RS011i002p00083
 Bibcode:
 1976RaSc...11...83T
 Keywords:

 Frequency Response;
 Radio Scattering;
 Specular Reflection;
 Surface Roughness Effects;
 Diffuse Radiation;
 Low Pass Filters;
 Planetary Surfaces;
 Scattering Cross Sections;
 Statistical Analysis