2012 Volume 118 Issue 10 Pages 632-649
Eolian dunes are particularly suited for comprehensive planetary studies because they are generally present on terrestrial planets, including Earth, Mars, Venus, and Saturn's moon Titan. Although the distribution and orientation of eolian dunes are thought to record surface wind patterns and atmospheric circulation systems on planets and moons, the validity of this idea has not been fully tested. In this study, I compared general circulation model (GCM) reconstructions of the present-day atmospheric circulation systems on Mars and Titan with eolian dune orientations and dune field distributions. The reconstructed Martian surface wind patterns indicated by dune centroid azimuths (DCA) and dune slipface orientations (SF) are generally consistent with the predominant surface wind patterns during the northern Martian hemisphere winter. In addition, dune fields are concentrated in high-latitude areas adjacent to areas with strong winds associated with the descending part of the Hadley circulation cell. This indicates that the distribution of dune fields and dune orientation patterns provide a record of atmospheric circulation patterns on Mars. In comparison, dune orientation-based wind pattern reconstructions on Titan are not consistent with GCM-based atmospheric circulation patterns. This discrepancy is thought to relate to occasional fast westerly winds during equinoxes that dominate the eastward streamlining pattern of Titan's dunes. Nevertheless, dune field distributions are reflected in atmospheric circulation patterns on Titan. Therefore, although eolian dune orientations are not always consistent with prevailing planetary and lunar atmospheric circulation patterns, the distribution of dune fields generally does reflect these patterns.
