Equilibrium versus disequilibrium of barchan dunes

被引：30
|
作者：
El Belrhiti, Hicham [1 ]
Douady, Stephane [2 ]
机构：
[1] Commiss European Communities, Joint Res Ctr, IES, Land Management & Nat Hazards Unit, I-21027 Ispra, VA, Italy
[2] Univ Paris Diderot, Lab Matiere & Syst Complexes, F-75205 Paris 13, France
来源：
GEOMORPHOLOGY | 2011年 / 125卷 / 04期
关键词：
Barchan; Shape; Instability; Migration; Morphodynamics; Equilibrium; Disequilibrium; SAND-DUNES; SILVER PEAK; DESERT; GEOMORPHOLOGY; MORPHOLOGY; TRANSPORT; SLOPE; MODEL; WIND;
D O I：
10.1016/j.geomorph.2010.10.025
中图分类号：
P9 [自然地理学];
学科分类号：
0705 ; 070501 ;
摘要：
Barchans are crescentic dunes which occur in mainly mono-directional winds. Shape, aspect ratios and velocities of these dunes have been studied as if they were in equilibrium. However, following a study of the shape and migration of 11 barchans of different sizes for 18 months in the field on Moroccan Atlantic Sahara, we show that they only appear to be in a stationary state if studied over a long timeframe (at the scale of the year or several years), but are never in equilibrium at the scale of weeks or months. Rather, they are always 'trying' to reach a possible equilibrium state but never have enough time to accomplish this. This may be the main reason for the large variation observed in previous measurements, and justifies some caution in what can be deduced from them. (C) 2010 Elsevier B.V. All rights reserved.
引用
收藏
页码：558 / 568
页数：11
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