3. Tifernine Dune Field, Algeria, Sahara
The Tifernine Dunes form the southernmost part of the Grand Erg Oriental, one of the most desolate parts of the Sahara. The nearest oasis is 100 kilometers (62 miles) away. The structures within the dune field are highlighted by the evening Sun, giving a better perspective on their height and morphology. To the north of the photograph the dunes most frequently form in long crescents or "barchans" with a steep, convex face toward the prevailing winds from the west or southwest. To the south of the dune field star dunes predominate, indicating that there is no consistent wind direction there.
Even in the driest parts of the Sahara the landscape has been largely shaped by flowing water. The deeply incised gullies at lower left are drainage channels probably cut during late glacial times, during a period of heavier rainfall. Flash floods following very rare rainstorms may cause minor modifications at the present day.
STS-2, November 1981. Picture #2-12-0810.