DOI: 10.1038/ngeo2406
论文题名: Methane storms as a driver of Titan's dune orientation
作者: Charnay B. ; Barth E. ; Rafkin S. ; Narteau C. ; Lebonnois S. ; Rodriguez S. ; Courrech Du Pont S. ; Lucas A.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2015
卷: 8, 期: 5 起始页码: 362
结束页码: 366
语种: 英语
Scopus关键词: climate modeling
; dune
; eolian deposit
; gravity
; methane
; momentum
; numerical model
; planetary landform
; prediction
; Saturn
; storm
; Titan
; topography
英文摘要: The equatorial regions of Saturn's moon Titan are covered by linear dunes that propagate eastwards. Global climate models (GCMs), however, predict westward mean surface winds at low latitudes on Titan, similar to the trade winds on Earth. This apparent contradiction has been attributed to Saturn's gravitational tides, large-scale topography and wind statistics, but none of these hypotheses fully explains the global eastward propagation of dunes in Titan's equatorial band. However, above altitudes of about 5 km, Titan's atmosphere is in eastward super-rotation, suggesting that this momentum may be delivered to the surface. Here we assess the influence of equatorial tropical methane storms - which develop at high altitudes during the equinox - on Titan's dune orientation, using mesoscale simulations of convective methane clouds with a GCM wind profile that includes super-rotation. We find that these storms produce fast eastward gust fronts above the surface that exceed the normal westward surface winds. These episodic gusts generated by tropical storms are expected to dominate aeolian transport, leading to eastward propagation of dunes. We therefore suggest a coupling between super-rotation, tropical methane storms and dune formation on Titan. This framework, applied to GCM predictions and analogies to some terrestrial dune fields, explains the linear shape, eastward propagation and poleward divergence of Titan's dunes, and implies an equatorial origin of dune sand. © 2015 Macmillan Publishers Limited. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/106209
Appears in Collections: 气候减缓与适应 科学计划与规划
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作者单位: Virtual Planetary Laboratory, University of Washington, Box 351580, Seattle, WA, United States; Laboratoire de Météorologie Dynamique, IPSL/CNRS/UPMC, Paris, France; Southwest Research Institute, Boulder, CO, United States; Institut de Physique du Globe de Paris, CNRS-UMR 7154, Université Paris-Diderot, Paris, France; Laboratoire Astrophysique, Instrumentation et Modélisation, CNRS-UMR 7158, Université Paris-Diderot, Gifsur Yvette, France; Laboratoire de Matière et Systèmes Complexes, CNRS-UMR 7057, Université Paris-Diderot, Paris, France
Recommended Citation:
Charnay B.,Barth E.,Rafkin S.,et al. Methane storms as a driver of Titan's dune orientation[J]. Nature Geoscience,2015-01-01,8(5)