Barchandünen

Barchandünen, also known as transverse dunes, are a common type of sand dune characterized by their crescent shape. They form in environments where there is a unidirectional wind and a limited supply of sand. The wind erodes sand from one side, creating a gently sloping windward face, and deposits it on the leeward side, forming a steeper slip face. The horns or crests of the barchan dune point in the direction of the prevailing wind. These dunes are migratory, slowly moving across the landscape as sand is transported from the windward to the leeward side. Their size can vary significantly, from a few meters to several hundred meters in width. Barchandünen are often found in deserts and coastal areas. The characteristic shape is a result of the wind flow dynamics around the dune. The sand accumulates on the leeward side due to eddies forming in the wind, which causes sand to fall down the slip face. The horns are formed by the wind flowing around the edges of the dune, transporting sand outwards. This continuous process of erosion and deposition allows the barchan dune to maintain its shape as it moves.