Barchan Dune Landscape or Crescent Dune Landscape
Reference work entry
This is a type of sand dune resembling a crescent moon and is the most basic type of mobile dune. Sand tends to accumulate into a crescent moon shape on a planar surface due to the wind. It is a mature form of dune development. The dunes move because of the wind and can reach heights of more than ten metres and widths from tens to hundreds of metres. The two slopes of the dune are asymmetrical. The windward slope is convex and gentle with a gradient of 5–20°, but the leeward slope is concave and steep with a dip of 28–34°. The two slopes connect to form an arc-shaped ridge. The dune ends extend along the prevailing wind direction. The extent is controlled by the strength of the dominant wind. The stronger the dominant wind, the smaller is the angle of intersection. Barchan dunes are often found along the desert margins and in large deserts. Chains of large barchan dunes can be found along the middle of the Southern Xinjiang Desert Highway in Xinjiang Province (Fig. 7).
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