Saltation under Martian gravity and its influence on the global dust distribution
General circulation model
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Dust and sand motion are a common sight on Mars. Understanding the interaction of atmosphere and Martian soil is fundamental to describe the planet’s weather, climate and surface morphology. We set up a wind tunnel to study the lift of a mixture between very fine sand and dust in a Mars simulant soil. The experiments were carried out under Martian gravity in a parabolic flight. The reduced gravity was provided by a centrifuge under external microgravity. The onset of saltation was measured for a fluid threshold shear velocity of 0.82 ± 0.04 m/s. This is considerably lower than found under Earth gravity. In addition to a reduction in weight, this low threshold can be attributed to gravity dependent cohesive forces within the sand bed, which drop by 2/3 under Martian gravity. The new threshold for saltation leads to a simulation of the annual dust cycle with a Mars GCM that is in agreement with observations.
CitationMusiolik, G.; Kruss, M.; Demirci, T.; Schrinski, B.; Teiser, J.; Daerden, F.; Smith, M.D.; Neary, L.; Wurm, G. (2018). Saltation under Martian gravity and its influence on the global dust distribution. , Icarus, Vol. 306, 25-31, DOI: 10.1016/j.icarus.2018.01.007.