DOI: 10.1038/ngeo2323
论文题名: Sand dune patterns on Titan controlled by long-term climate cycles
作者: Ewing R.C. ; Hayes A.G. ; Lucas A.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2015
卷: 8, 期: 1 起始页码: 15
结束页码: 19
语种: 英语
Scopus关键词: climate cycle
; dune
; long-term change
; radar
; satellite imagery
; Saturn
; spacecraft
; tidal cycle
; Titan
; wind direction
英文摘要: Linear sand dunes cover the equatorial latitudes of Saturn's moon Titan and are shaped by global wind patterns. These dunes are thought to reflect present-day diurnal, tidal and seasonal winds, but climate models have failed to reproduce observed dune morphologies with these wind patterns. Dunes diagnostic of a specific wind or formative timescale have remained elusive. Here we analyse radar imagery from NASA's Cassini spacecraft and identify barchan, star and reoriented dunes in sediment-limited regions of Titan's equatorial dune fields that diverge by 23° on average from the orientation of linear dunes. These morphologies imply shifts in wind direction and sediment availability. Using a numerical model, we estimate that the observed reorientation of dune crests to a change in wind direction would have taken around 3,000 Saturn years (1 Saturn year 29.4 Earth years) or longer-a timescale that exceeds diurnal, seasonal or tidal cycles. We propose that shifts in winds and sediment availability are the product of long-term climate cycles associated with variations in Saturn's orbit. Orbitally controlled landscape evolution-also proposed to explain the distribution of Titan's polar lakes-implies a dune-forming climate on equatorial Titan that is analogous to Earth. © 2014 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/106203
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: Department of Geology and Geophysics, Texas A and M University, College Station, TX, United States; Department of Astronomy, Cornell University, Ithaca, NY, United States; Laboratoire AIM, Université Paris-Diderot, CEA-SACLAY, Gif sur Yvette, France
Recommended Citation:
Ewing R.C.,Hayes A.G.,Lucas A.. Sand dune patterns on Titan controlled by long-term climate cycles[J]. Nature Geoscience,2015-01-01,8(1)