http://arxiv.org/abs/2203.00562
Sediment transport by atmospheric winds shapes the surface and affects the climates of planetary bodies. Reliably predicting the occurrence and rate of sediment transport in the Solar System has been notoriously difficult because fluid density, grain size and soil cohesiveness vary across many orders of magnitude. Here, we use recent advances in analytical and numerical sediment transport modeling to derive general scaling relations for planetary transport. In particular, we show that the equations of motion of rebounding grains predict that the minimum threshold fluid shear velocity needed to sustain transport (transport cessation threshold) scales with the particle-fluid-density ratio ($s$) as $s^{1/3}$, in contrast to the $s^{1/2}$-scaling exhibited by the threshold for transport initiation. The grain size corresponding to this minimum is in the range $80{-}290~\mu\mathrm{m}$ for Solar System bodies. Our results, summarized in phase diagrams for the cessation threshold, mean transport rate and dust emission potential, explain the observed eastward propagation of Titan’s dunes, in spite of a predominantly westward wind circulation, indicate active dust cycles on Earth, Mars and Titan, and suggest marginal but active atmospheric transport on Venus, Triton and Pluto.
T. Pähtz, O. Duŕan and F. Comola
Wed, 2 Mar 22
36/54
Comments: N/A