Thermal creep assisted dust lifting on Mars: Wind tunnel experiments for the entrainment threshold velocity
arXiv:1508.01047 · doi:10.1002/2015JE004848
Abstract
In this work we present laboratory measurements on the reduction of the threshold friction velocity necessary for lifting dust if the dust bed is illuminated. Insolation of a porous soil establishes a temperature gradient. At low ambient pressure this gradient leads to thermal creep gas flow within the soil. This flow leads to a sub-surface overpressure which supports lift imposed by wind. The wind tunnel was run with Mojave Mars Simulant and air at 3, 6 and 9 mbar, to cover most of the pressure range at martian surface levels. Our first measurements imply that the insolation of the martian surface can reduce the entrainment threshold velocity between 4 % and 19 % for the conditions sampled with our experiments. An insolation activated soil might therefore provide additional support for aeolian particle transport at low wind speeds.
accepted by JGR:Planets, 12 pages, 7 figures, 3 tables
References in corpus (4)
- Eight-year Climatology of Dust Optical Depth on Mars
- Difference in the wind speeds required for initiation versus continuation of sand transport on Mars: Implications for dunes and dust storms
- Dust Ejection from Planetary Bodies by Temperature Gradients: Laboratory Experiments
- An Insolation Activated Dust Layer on Mars