A rough-surface scattering function for Titan radar studies

Abstract

Numerous studies show a relationship between radar backscattering and surface roughness. While estimating the statistical properties of small-scale topography is of particular interest for geologic analysis of Cassini radar data, there is no analytic description of radar scattering over a wide range of incidence angles and roughness. This paper presents an empirical function that links the rms slope at the horizontal scale of the wavelength and HH- or VV-polarization radar echoes. The model is based on comparison of 24-cm wavelength AIRSAR data for lava flows in Hawai'i, at incidence angles of 25° to 55°, with topographic profiles at 25-cm posting. Comparison of model predictions to the range of observed Titan echoes suggests that the radar return is often dominated by a component arising from subsurface scattering.