The area shown here (10 kilometers across) is a small part of the dune field which is now protected as the Len&ccelde;óis Maranhenses National Park, on Brazil’s north coast, about 700 kilometers east of the Amazon River mouth. Persistent winds blow off the equatorial Atlantic Ocean onto Brazil from the east, driving white sand inland from the 100 kilometer stretch of coast (upper margin of the image), to form a large field of dunes. The strongly regular pattern of these dunes is a common characteristic of dune fields. The basic shape of each sand mass, repeated throughout the view, is a crescent-shaped dune. In an area with a rich supply of sand such as coastal Brazil, individual crescents coalesce to form entire chains many miles long. The wind strength and supply of sand are sufficient to keep the dunes active, and thus free of vegetation, despite 1500 mm (60 inches) of rainfall annually. The dark areas between the white dunes are fresh water ponds that draw fisherman to this newly established park.
Published Oct 20, 2003
This astronaut photograph shows classic large and small sand masses of the central Sahara Desert, where wind is a more powerful land-shaping agent than water.
Published Jan 19, 2009
Layers of dunes march across a sand sea in the east-central Tenéré Desert of Niger in this astronaut photo from December 1, 2009.
Published Dec 28, 2009
This detailed true-color image from February 24, 2011, shows the variety of sand dunes that make up the Algodones Dunes in southeastern California.
Published May 27, 2011
Winds shape the sands that were left behind by an ancient river.
Published Jun 4, 2012
Sand dunes sprawl along the coast of northeastern Brazil, sometimes extending kilometers inland.
Published Jul 11, 2010
Acquired June 12, 2010, this natural-color image shows camel-colored sand dunes marching past Mongolia’s Har Nuur.
Published Jun 27, 2010
