COMPARISON OF GOLDSTONE AND MAGELLAN RADAR DATA IN THE EQUATORIAL PLAINS OF VENUS

Goldstone radar observations of the equatorial plains of Venus provide complementary information to that obtained by Magellan. Different radar scattering mechanisms dominate each system, leading to a sampling of different surface properties. Comparison of image data and derived parameters indicate that (1) relatively high dielectric constants on impact-related parabolic features are detected in Goldstone backscatter, Magellan reflectivity, and Magellan emissivity data; the dielectric effects are overwhelmed by roughness-related signatures in Magellan synthetic aperature radar (SAR) data, (2) lava flows in Navka Planitia show dielectric variations both among and with flows; higher dielectric constants on the perimeter of some flows may be due to a decrease in vesicularity, (3) some volcanic domes are relatively smooth at the wavelength scale and probably consist of low-density deposits, (4) comparisons of Magellan SAR data with rough surface scattering models and SAR data of terrestrial surfaces indicate that the roughness characteristics of the equatorial plains surfaces are comparable to modified terrestrial lava flows, and (5) scattering properties of an equatorial "ridge belt" structure suggest highly weathered or soil-dominated surfaces.