2. Sossus Vlei, Namibia
This Skylab 4 picture of one section of the area in the Namibian Desert covered by slide #1 was taken 10 years before the shuttle picture. Apparent color differences are due to lighting, viewing geometry, and photographic processing. An intricate network of patterning can be seen in the dunes at Sossus Vlei. Long parallel dunes are constructed by the prevailing wind coming off the coast, but where the dune field meets rocky outcrops leading to higher ground eolian transport is confused, and smaller, distinct, peaking dunes, sometimes called star dunes, are produced.
A comparison of slide #1 and this slide shows virtually no change in the morphology or distribution of the dunes over the 10-year period, at least at the scale of the photographic resolution, about 50 meters (165 feet). While in some desert regions dunes migrate relatively rapidly, climatic conditions in Namibia have remained stable and the dune pattern changes only slowly.
Skylab 4, November 1973-February 1974. Picture #SL4-207-8073.