barchan dune

bar·chan dune

 (bär-kän′)
n.
A crescent-shaped dune, reaching heights of up to 30 meters (98 feet) and widths of 350 meters (1,148 feet), and having a steep, concave leeward side with crescent tips pointing downwind.

[Russian barkhan, barchan dune, from Kazakh barxan; akin to Uyghur bargan, dune that moves.]
References in periodicals archive ?
The Kalahari Sands Hotel is sponsoring accommodation for the visiting legends, while Air Namibia chipped in with a good discount, AVIS Car Rental is sponsoring two mini buses to transport the sports legends, Barchan Dune Retreat is sponsoring a hunt and accommodation for some of the players, Xco Namibia assisted with promotional items The sister companies in the CIH Group of companies will also be part of the day.
Half of the traps were set on the advancing side of a barchan dune (Muma 1980).
Inevitably, the points of the barchan dune become snagged and firmly anchored.
Now, a new mathematical model for wind-driven sand, as well as computer simulations of the same, reveal that one Barchan dune can, indeed, act as a soliton and pass through a slower-moving dune.
Barchan dunes are massive, crescent-shaped sand piles that move across windswept deserts at speeds up to tens of meters per year.
The management has also 1) carried out studies to assess the viability of replanting and stabilizing the barchan dune fields, 2) conducted research into the physiology of native plants and animals to see how they react to changes in salinity, temperature, and aridity, 3) studied the changes in the soil moisture regime, and 4) measured the effects of grazing on plant productivity.
They are formed when the largest symmetrical undulations become asymmetrical and adopt the typical profile of a barchan dune, with a steep slope on the leeward side.
It's unclear why barchan dunes exist at all," says Pieter Vermeesch, a geologist at University College London.
The Empty Quarter is the biggest desert in the world, so rolling dunes, the challenging barchan dunes (arc-shaped sand ridges) I know to expect, but am most looking forward to sleeping under the stars in the Empty Quarter.
It appears that a change in wind direction has blown the crescent tails from a field of so-called barchan dunes.
and is characterised by large and concentrated sand dunes in the form of reticulated chains of barchan dunes with natural vegetation cover of <1%.
The largest sand structures (rhourds, linear dunes or seifs, elbs, and silks) are stable, while barchan dunes may move dozens of meters a year (even hundreds of meters in the sand tongues of Patagonia).