Radar Measurements of the Surface Topography and Roughness of Mars


  • A. E. E. Rogers,

  • M. E. Ash,

  • C. C. Counselman,

  • I. I. Shapiro,

  • G. H. Pettengill


During the period surrounding the 1969 opposition, the planet Mars was observed with the Haystack radar to determine the topography in a belt near the equator. Elevation values obtained for the same surface location on Mars on different days of observation agree, for high signal-to-noise ratio cases, to within about 100 meters. Preliminary results show that the variation of surface height with longitude between latitudes 3°N and 12°N is similar to that measured for latitudes near 22°N during the 1967 opposition. The most notable difference is found near 215° longitude, where at 22°N there is a highland at Elysium, although at 5°N a lowland is found. Optically dark regions often have a high radar cross section. However, the topography shows no significant correlation with either the visual or the radar brightness.