Radar reflectivities of plausible Titan surfaces

We consider plausible reflectivity ranges for candidate Titan surfaces, with application to radar altimeter investigations on both the Cassini Orbiter and Huygens Probe. The appropriate measure of surface scattering is the specific backscatter cross-section at normal incidence or, for smooth surfaces, the specific backscatter averaged over the sensitivity of the altimeter beam pattern. A clean ethane ocean gives cross-sections as low as 0.3-0.6. Maximum backscatter cross-sections for solid surfaces are typically of the order 10-100, though over very localised regions they might be two orders of magnitude higher.