Revisiting Titan's Earth-based scattering data at 13 cm-λ

Earth-based measurements of scattering from Titan's surface at 13 cm-λ obtained by the Arecibo Observatory provide an almost complete record over longitude of the backscattering spectra from the surface of Titan at 25.5°S. The observations contain a quasi-specular component, indicating the presence of smooth surfaces on wavelength scale, that is distinct from an omni-present diffuse background. Previous modeling of this scattering using Hagfors law produces values for the surface dielectric constant consistent with liquid hydrocarbons. Use of plausible alternative models, such as a linear combination of two Gaussian scattering laws, yields higher dielectric constant results, which are consistent with a solid surface of simple organics or "dirty" water ice. In instances where several scattering laws are plausible models for the data, it is helpful to check the consistency of the inferred surface parameters before making conclusions concerning surface composition. Copyright 2007 by the American Geophysical Union.