Circular‐polarization radar properties of high‐altitude ice: Western Kunlun Shan and central Andes

Abstract

Full polarization synthetic aperture radar images of high‐altitude glaciers and ice fields in the Western Kunlun Shan of Tibet and the central Andes near Santiago, Chile, made with the shuttle imaging radar, display regions with circular‐polarization ratios, μc, in excess of unity. The mountainous topography at both locales allows reconstruction of the angular scattering behavior. The behavior is very similar to that displayed by Greenland's percolation zone. Glaciologic evidence from the Tibetan site confirms ice pipes and lenses embedded in the firn, which have been identified as the scatterers producing μc>1 in Greenland. This demonstrates that the cold snow percolation facies radar signature exists outside of Greenland. The Greenland radar behavior had been suggested as an analogue for that of the icy Galilean satellites. We, like previous workers, find that the near‐nadir backscatter is too specular to be considered analogous to that of the Jovian moons. We also present a crevasse region in Tibet that exhibits μc>1 and a possible detection of the ice substrate of a rock‐covered glacier in the Andes.