Conditions for aeolian transport in the Solar System
Conditions for aeolian transport in the Solar System
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DOI：
10.1038/s41550-022-01669-0
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发表时间：
2022-05-19
期刊：
影响因子：
14.1
通讯作者：
Jerolmack, Douglas J.
中科院分区：
文献类型：
--
作者：
Gunn, Andrew;Jerolmack, Douglas J.
沙丘在太阳系中无处不在(2)，沙丘是由超过阈值速度的风将松散的沉积物动员起来，并且颗粒足够强大，可以在碰撞中幸存下来的地方形成的。然而，目前的阈值理论通常忽略了在外来条件下相关的物理过程（3,4），并且在外推到地外行星体时存在分歧（5-9）。在这里，我们利用接触力学（10）、稀薄气体力学（11）、统计力学（12）和粘附力学（13）的结果，提出了一个包含太阳系天体中存在的各种条件的风成运输的流体和冲击阈值的理论。我们的理论预测与现有的实验阈值观测结果一致，并表明这些阈值在很大程度上取决于地球以外的其他地方的当地环境条件。我们的研究结果表明，除其他因素外，土卫六的沙丘来自当地(4)，而火星的高阈值使其沙丘更能抵抗运动（14）。这项工作强调了沙丘在理解大气动力学和地表沉积物中的作用。需要进一步的研究，包括迄今为止被忽视和仍然知之甚少的过程。
Sand dunes, which arise wherever loose sediment is mobilized by winds that exceed threshold speed and grains are sufficiently strong to survive collisions', are ubiquitous in the Solar System(2). However, current threshold theories usually neglect physical processes that become relevant under exotic conditions(3,4), and are in disagreement when extrapolated to extraterrestrial planetary bodies(5-9). Here we draw on results in contact(10), rarefied gas(11), statistical(12) and adhesion(13) mechanics to present a theory for the fluid and impact thresholds of aeolian transport that encompasses the various conditions present in Solar System bodies. Our theoretical predictions are consistent with available experimental threshold observations and indicate that these thresholds strongly depend on local environmental conditions everywhere but Earth. Our results suggest, among other things, that Titan's dunes are locally sourced(4) and that Mars's high threshold makes its dunes more resistant to motion(14). This work highlights the role of dunes in understanding atmospheric dynamics and surface sediment. Further studies are needed to include hitherto neglected and still poorly understood processes.