How Sand Dunes Grow Huge

Giant dunes in Grand Erg Oriental, Algeria. Credit: Bruno Andreotti

From Live Science:

Anyone who has seen giant sand dunes, the tall ones stretching many hundreds, even thousands, of feet across the desert floor, has surely wondered how they get to be so big. Scientists, too, have deliberated the question for years.

The sandy behemoths form in China, the Sahara, Namibia, and Iran, among other desert areas, and they come in ridge, star, or crescent shapes.

Bruno Andreotti and Philippe Claudin of the Laboratory of the Physics and Mechanics of Heterogeneous Media in Paris and colleagues now have some answers. The team studied giant-dune fields on-site, analyzed aerial and satellite photos and meteorological data, and ran aerodynamic models to investigate dune growth.

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