Roughness of the Moon as a Radar Reflector

Abstract

IN a recent communication¹ Hughes has suggested that the law of scattering of radio waves by the lunar surface is consistent with scattering by a rough surface which has irregularities much greater than the radio wave-length, and such that the root mean square value of the slope is about 1 in 20, or 3°. The law of scattering as a function of angle of incidence which, on this model, would be the same as the distribution of the slope of the irregular surface, was found from radar observations to be given by : where σ is the effective scattering area and θ the angle of incidence.