气候变化领域集成服务门户(CCPortal): A lower-than-expected saltation threshold at Martian pressure and below

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DOI	10.1073/pnas.2012386118
	A lower-than-expected saltation threshold at Martian pressure and below
	Andreotti B.; Claudin P.; Iversen J.J.; Merrison J.P.; Rasmussen K.R.
发表日期	2021
ISSN	00278424
卷号	118 期号:5
英文摘要	Aeolian sediment transport is observed to occur on Mars as well as other extraterrestrial environments, generating ripples and dunes as on Earth. The search for terrestrial analogs of planetary bedforms, as well as environmental simulation experiments able to reproduce their formation in planetary conditions, are powerful ways to question our understanding of geomorphological processes toward unusual environmental conditions. Here, we perform sediment transport laboratory experiments in a closed-circuit wind tunnel placed in a vacuum chamber and operated at extremely low pressures to show that Martian conditions belong to a previously unexplored saltation regime. The threshold wind speed required to initiate saltation is only quantitatively predicted by state-of-the art models up to a density ratio between grain and air of 4 × 105 but unexpectedly falls to much lower values for higher density ratios. In contrast, impact ripples, whose emergence is continuously observed on the granular bed over the whole pressure range investigated, display a characteristic wavelength and propagation velocity essentially independent of pressure. A comparison of these findings with existing models suggests that sediment transport at low Reynolds number but high grain-to-fluid density ratio may be dominated by collective effects associated with grain inertia in the granular collisional layer. © 2021 National Academy of Sciences. All rights reserved.
英文关键词	Impact ripples; Mars; Saltation at low pressure; Sediment transport threshold
语种	英语
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/180787
作者单位	Laboratoire de Physique de l’Ecole Normale Supérieure, UMR 8023, CNRS, Université de Paris, PSL Research University, Paris, 75005, France; Physique et Mécanique des Milieux Hétérogènes, UMR 7636, CNRS, École Supérieure de Physique et de Chimie Industrielles de la Ville de Paris, PSL Research University, Sorbonne Université, Université de Paris, Paris, 75005, France; Department of Physics and Astronomy, Aarhus University, Aarhus C, 8000, Denmark; Department of Geoscience, Aarhus University, Aarhus C, 8000, Denmark
推荐引用方式 GB/T 7714	Andreotti B.,Claudin P.,Iversen J.J.,et al. A lower-than-expected saltation threshold at Martian pressure and below[J],2021,118(5).
APA	Andreotti B.,Claudin P.,Iversen J.J.,Merrison J.P.,&Rasmussen K.R..(2021).A lower-than-expected saltation threshold at Martian pressure and below.Proceedings of the National Academy of Sciences of the United States of America,118(5).
MLA	Andreotti B.,et al."A lower-than-expected saltation threshold at Martian pressure and below".Proceedings of the National Academy of Sciences of the United States of America 118.5(2021).