Mesoscale Roughness of Venus
Abstract
The global distribution of multikilometer (approx. 9 km) length scale 'roughness' (hereafter mesoscale roughness or MR) on Venus can be estimated from the Magellan global altimetry dataset (GxDR) and then compared with MR data derived for Earth from 5' ETOP5 data and for Mars (from USGS Mars DTM dataset). The mesoscale roughness parameter (MR) represents the RMS variance in meters of the actual planetary surface topography relative to the best fitting tangent plane defined on the basis of a 3x3 pixel sliding window. The bestfit plane was computed using a leastsquares solution which minimizes delta H, the sum of the squares of the differences between the 9 local elevation values (H_{i}), and the elevation of bestfit plane at the same grid location. Using the bestfit plane and delta H, we have computed the RMS 'roughness' var(delta R), where this parameter is always minimized on the basis of its calculation using least squares. We have called this 'ruggedness' parameter the Mesoscale Roughness (MR) because it is directly related to the highfrequency variance of topography after mesoscale slopes and tilts (i.e., for Venus, the baseline over which MR is computed (dx) is approx. 8.8 km and dx for Earth is approx. 9.3 km) are removed. As such, MR represents the degree to which a planetary surface is more rugged than approximately 10 km scale facets or tilts. It should not be confused with the radar 'RMS Roughness' parameter computed at 0.1 to 10 m length scales on the basis of the Magellan radar altimeter echo. We will use our MR parameter to investigate the global ruggedness properties of Venus as they relate to geological provinces and in comparison with the spatial pattern of MR for Earth and Mars.
 Publication:

Lunar and Planetary Science Conference
 Pub Date:
 March 1994
 Bibcode:
 1994LPI....25..407G
 Keywords:

 Geological Surveys;
 Mesoscale Phenomena;
 Position (Location);
 Radio Altimeters;
 Satellite Altimetry;
 Surface Roughness;
 Topography;
 Venus Surface;
 Flat Surfaces;
 Pixels;
 Planetary Geology;
 Ruggedness;
 Slopes;
 Lunar and Planetary Exploration