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behavior, but unlike solitons, which flow through a medium leaving it undisturbed (similar to waves passing through water), the sand particles themselves are moved. When the smaller dune catches up the larger dune, the winds begin to deposit sand on the rear dune while blowing sand off the front dune
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As barchan dunes migrate, smaller dunes outpace larger dunes, catching-up the rear of the larger dune and eventually appear to punch through the large dune to appear on the other side. The process appears superficially similar to waves of light, sound, or water that pass directly through each other,
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dunes, which can gradually migrate with the wind as a result of erosion on the windward side and deposition on the leeward side, at a rate of migration ranging from about one meter to 100 meters per year. Barchans usually occur as groups of isolated dunes and may form chains that extend across a
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of the sand in question, approximately 30–35 degrees for medium-fine dry sand. The upwind side is packed by the wind, and stands at about 15 degrees. Barchans may be 9–30 m (30–98 ft) high and 370 m (1,210 ft) wide at the base measured perpendicular to the wind.
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plain in the direction of the prevailing wind. Barchans and mega-barchans may coalesce into ridges that extend for hundreds of kilometers. Dune collisions and changes in wind direction spawn new barchans from the horns of the old ones and govern the size distribution of a given field.
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without replenishing it. Eventually, the rear dune has assumed dimensions similar to the former front dune which has now become a smaller, faster moving dune that pulls away with the wind.
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all over the world and are arc-shaped, markedly asymmetrical in cross section, with a gentle slope facing toward the wind sand ridge, comprising well-sorted
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This type of dune possesses two "horns" that face downwind, with the steeper slope known as the slip face, facing away from the wind, downwind, at the
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289:
Alvarez, Carlos A.; Franklin, Erick M. (2018-10-19). "Role of
Transverse Displacements in the Formation of Subaqueous Barchan Dunes".
164:, also known as Zastruga – Sharp irregular grooves or ridges formed on a snow surface, about snowforms of similar mechanism
615:
Couldrey, Amelia J.; Benson, Thomas; Knaapen, Michiel A.F.; Marten, Kerry V.; Whitehouse, Richard J.S. (30 September 2020).
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H. Elbelrhiti; P. Claudin & B. Andreotti (2005). "Field evidence for surface-wave-induced instability of sand dunes".
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98:, appearing convex and are produced by wind action predominantly from one direction. They are a very common
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196:
631:
617:"Morphological evolution of a barchan dune migrating past an offshore wind farm foundation"
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Alvarez, Carlos A.; Franklin, Erick M. (2017-12-18). "Birth of a subaqueous barchan dune".
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Schwämmle, V. & H.J. Herrmann (2003). "Solitary wave behaviour of sand dunes".
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142:, where the thin atmosphere produces winds strong enough to move sand and dust.
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667:"Shifting sands: R&D gurus report in on scour of 'marching' seabed dunes"
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401:"A Comprehensive Picture for Binary Interactions of Subaqueous Barchans"
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but the detailed mechanism is very different. The dunes emulate
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Simple barchan dunes may appear as larger, compound barchan or
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352:"Collision of barchan dunes as a mechanism of size regulation"
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appear underwater as sands shift their way across the seabed.
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82:. The term was introduced in 1881 by Russian naturalist
588:Nemiroff, R.; Bonnell, J., eds. (April 20, 2009).
569:Nemiroff, R.; Bonnell, J., eds. (March 3, 2008).
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158: – National park in Colorado, United States
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399:Assis, W. R.; Franklin, E. M. (2020-09-28).
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156:Great Sand Dunes National Park and Preserve
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350:Hersen, Pascal; Douady, Stéphane (2005).
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677:from the original on 1 November 2020.
624:Earth Surface Processes and Landforms
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698:The Bibliography of Aeolian Research
665:Snieckus, Darius (23 October 2020).
590:"Flowing Barchan Sand Dunes on Mars"
138:Barchan dunes have been observed on
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23:. For the military operation, see
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195:Pye, Kenneth; Haim Tsoar (2008).
693:—Great Sand Dunes National Park
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86:, based on their occurrence in
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321:10.1103/PhysRevLett.121.164503
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1:
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595:Astronomy Picture of the Day
576:Astronomy Picture of the Day
571:"Sand Dunes Thawing on Mars"
405:Geophysical Research Letters
356:Geophysical Research Letters
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199:Aeolian Sand and Sand Dunes
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94:regions. Barchans face the
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730:
260:10.1103/PhysRevE.96.062906
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472:(September 29): 720–723
84:Alexander von Middendorf
527:(December 11): 619–620
291:Physical Review Letters
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203:. Springer. pp.
182:"Barchan - sand dune"
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19:For the village, see
435:10.1029/2020GL089464
377:10.1029/2005GL024179
144:Marine barchan dunes
16:Crescent-shaped dune
636:2020ESPL...45.2884C
565:See for instance:
490:10.1038/nature04058
482:2005Natur.437..720E
427:2020GeoRL..4789464A
368:2005GeoRL..3221403H
313:2018PhRvL.121p4503A
252:2017PhRvE..96f2906A
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630:(12): 2884–2896.
230:Physical Review E
90:and other inland
71:[bɑɾˈχɑn]
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41:Typical shape
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21:Barchan, Iran
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62:barkhan dune
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51:Namib Desert
123:megabarchan
691:Dune types
418:2009.12671
304:1810.11074
243:1712.07162
169:References
652:225400184
451:221970569
443:0094-8276
386:0094-8276
88:Turkestan
708:Category
675:Archived
671:Recharge
545:14668849
529:Abstract
498:16193049
474:Abstract
337:53231618
329:30387641
276:25558699
268:29347350
162:Sastrugi
150:See also
100:landform
78:-shaped
76:crescent
25:Barkhane
632:Bibcode
506:4411463
478:Bibcode
423:Bibcode
364:Bibcode
309:Bibcode
248:Bibcode
132:soliton
74:) is a
68:бархан
58:barchan
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553:688445
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521:Nature
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466:Nature
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92:desert
66:Kazakh
64:(from
714:Dunes
648:S2CID
620:(PDF)
549:S2CID
502:S2CID
447:S2CID
413:arXiv
333:S2CID
299:arXiv
272:S2CID
238:arXiv
600:NASA
581:NASA
541:PMID
494:PMID
439:ISSN
382:ISSN
325:PMID
264:PMID
209:ISBN
140:Mars
108:sand
96:wind
80:dune
640:doi
533:doi
525:426
486:doi
470:437
431:doi
372:doi
317:doi
295:121
256:doi
205:138
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