How do barchan dunes differ from other dunes in the Namib Desert?

In the Namib Desert, barchan dunes differ from other prominent forms, such as the star dunes found near Sossusvlei, primarily in their formation and shape.12

• Wind Consistency: Barchans are crescent-shaped dunes that form in areas where the wind blows consistently from a single direction. In contrast, the star dunes of the Namib are shaped by winds blowing from multiple directions, resulting in a pyramidal structure with radiating arms.132
• Morphology: Barchans are characterized by a convex windward side and a steep slip face on the leeward side, with horns pointing downwind. They are relatively small, typically reaching heights of 9–30 meters. Conversely, the dunes in the Namib Sand Sea can reach massive heights of up to 325 meters.12
• Dune Hierarchy: While barchans often occur as isolated dunes or chains, the Namib also features complex, large-scale compound dunes (or draa), which are often covered by smaller, secondary dune patterns and ripples.3