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JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 109, E06009, doi:10.1029/2003JE002227, 2004

Impact crater related surficial deposits on Venus: Multipolarization radar observations with Arecibo

Lynn M. Carter

Department of Astronomy, Cornell University, Ithaca, New York, USA


Donald B. Campbell

Department of Astronomy and the National Astronomy and Ionosphere Center, Cornell University, Ithaca, New York, USA


Bruce A. Campbell

Center for Earth and Planetary Studies, National Air and Space Museum, Smithsonian Institution, Washington, D. C., USA


Abstract

The distribution of surficial deposits in the vicinity of impact craters on Venus was studied using measurements of the polarization properties of the reflected radar wave. Subsurface scattering of an incident circularly polarized radar signal results in a linearly polarized component in the radar echo due to the differing transmission coefficients at a smooth (at wavelength scales) atmosphere-surface boundary for the horizontal (H) and vertical (V) linearly polarized components of the incident wave. Arecibo 12.6 cm wavelength radar observations in 1999 and 2001 provided images of the surface of Venus in the full Stokes polarization parameters of the reflected echo, from which images in the degree of linear polarization were derived. These images show that substantial areas of Sedna, Guinevere, and Lavinia Planitias return a radar echo with a significant degree of linear polarization, indicating that mantling deposits may be relatively widespread on the plains of Venus. The areas showing linear polarization enhancements are strongly correlated with topographic features, primarily impact craters, dome fields, and windblown deposits, including dune fields. A strong linearly polarized echo component (∼10–40% linear polarization) is found from regions near 45 impact craters, including 5 parabolas. These linear polarization features typically correspond to diffuse, higher backscatter cross-section (bright) regions in Magellan images. The linearly polarized component in these regions is attributed to subsurface echoes from a mantled substrate or from buried rocks.

Received 19 December 2003; accepted 28 April 2004; published 22 June 2004.

Keywords: impact craters; radar; surface properties; Venus.

Index Terms: 6295 Planetology: Solar System Objects: Venus; 5420 Planetology: Solid Surface Planets: Impact phenomena (includes cratering); 5470 Planetology: Solid Surface Planets: Surface materials and properties; 5464 Planetology: Solid Surface Planets: Remote sensing; 6949 Radio Science: Radar astronomy.

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Citation: Carter, L. M., D. B. Campbell, and B. A. Campbell (2004), Impact crater related surficial deposits on Venus: Multipolarization radar observations with Arecibo, J. Geophys. Res., 109, E06009, doi:10.1029/2003JE002227.