A RADAR STUDY OF LUNAR CRATER TYCHO AT 3.8-CM AND 70-CM WAVELENGTHS

Maps of the intensity distribution of radar echoes at 3.8- and 70-cm wavelengths from the lunar surface are presented for the region surrounding the crater Tycho. Surface resolution at 3.8 cm was between 1 and 2 km and at 70 cm between 7 and 10 km. The average scattering enhancement for Tycho at 3.8 cm was found to be 2.0 ± 0.3 when observed in the polarized mode (signals received using a sense of circular polarization orthogonal to that transmitted). At 70 cm, average enhancements of 5.0 ± 1.0 and 15 ± 2 in the polarized and depolarized modes, respectively, were observed. Using assumptions derived from earlier observations, that 15% and 6% of the average lunar surface at wavelengths of 3.8 and 70 cm, respectively, acts as a diffuse scatterer, we find from our observations that approximately 80% of the interior surface of tycho scatters diffusely at these wavelengths. Modulation of the intensity distribution associated with localized crater slopes is also observed. © 1968.