Wavelength dependence of the radar reflectivity of the Earth and the Moon

Abstract

Recent interest in the use of a multifrequency radar as a remote sensor for exploration of the earth and the moon has stimulated this study of the variation of radar backscattering with change in electromagnetic wavelength. The analysis of data has shown that radar cross sections of land and sea surfaces decrease with increasing wavelength and, on the average, follow approximately a λ−1 behavior, although the exponent may vary from +2 to −6 in individual cases. Snow‐covered surfaces at all depression angles and sea surfaces at angles above 73° are the ones with positive values for the exponent. The wavelength dependence of the moon and the average values found on the earth in this study are quite similar. The combination of polarization and wavelength dependence versus depression angle may be characteristic features for distinguishing various terrain types by a multifrequency radar.

Very high frequency radiowave scattering by a disturbed sea surface Part II: Scattering from an actual sea surface

“…Thus in most cases, as the wavelength increases, the reflected intensity decreases (or at least remains constant) following the law a-A. (-2 < a l o), which is in agreement with the experimental results[19]-[25]. That there is no dependence of u on the height of the large…”

A survey of lunar geology, 10 January through 10 June, 1966

“…A range of a from -6 to -2 was predicted for both isotropic scatterers and facet-like specular reflectors. Katz [112] has recently discussed this concept in terms of currently available data from terrestrial reflectivity experiments. He averaged the available data from what he termed "apparently similar surfaces" at a given angle of incidence and concluded that the variation of the exponent a with depression angle was characteristic of a particular surface.…”