Characterizing Daytime Aeolian Erosion Potential on Mars Using a Turbulence-Resolving Atmospheric Model

Grant #: NNX08AU36G
Senior Scientist: Lori Fenton

A primary goal of Mars science is to understand the present-day interaction between the atmospheric environment and the planet’s surface that ultimately results in climatically- and geologically-important aeolian phenomena (e.g., dust storms, dust devils, albedo changes, dune migration, surface erosion). In particular, the actual patterns of (and processes causing) particle entrainment are poorly quantified. On Mars aeolian activity is produced by a combination of local processes that operate on a spatial scale of < 10 km (e.g., dust devils, convective wind gusts) that are superimposed on (and interact with) regional and global scale dynamics (e.g., slope winds, baroclinic eddies, fronts). Although the impact of regional- and global-scale dynamics on aeolian processes have been modeled and studied in detail, the potential aeolian impact (especially during the daytime) of the complex, highly three-dimensional dry convective circulations within the planetary boundary layer is neither well-quantified nor understood, although it is suspected to be quite significant.

A Large Eddy Simulation (LES) models atmospheric circulations to a much finer resolution than general circulation models (GCMs) and mesoscale models, resolving turbulent eddies down to the resolution of the model domain (10s to 100s of meters). Using an LES, we will characterize the relative variations in daytime aeolian erosion potential on Mars caused by changes in boundary layer convective structure as a result of time-of-day, season, surface elevation, latitude, and a variety of other parameters. We will investigate the ramifications of the full aeolian potential being realized, including dust entrainment, surface abrasion, bedform activity, saltation flux, and surface albedo modification. The proposed work is designed to bridge the gap in understanding between local- and global-scale aeolian processes and to apply this knowledge to interpreting the sedimentary and climate history of Mars.