This Landsat image shows the Turpan Depression in the rain shadow desert of the Tian Shan of China. A sand sea is in the lower center on the right, but desert pavement, gray in color, dominates this desert. The few oases in the desert and the vegetation in the mountains at the top are in red. A blanket of snow separates the vegetation in the Tian Shan from the rain shadow desert.
Coastal deserts
Coastal deserts generally are found on the western edges of continents near the Tropics of Cancer and Capricorn. They are affected by cold ocean currents that parallel the coast. Because local wind systems dominate the trade winds, these deserts are less stable than other deserts. Winter fogs, produced by upwelling cold currents, frequently blanket coastal deserts and block solar radiation. Coastal deserts are relatively complex because they are at the juncture of terrestrial, oceanic, and atmospheric systems. A coastal desert, the Atacama of South America, is the Earth’s driest desert. In the Atacama, measurable rainfall—1 millimeter or more of rain—may occur as infrequently as once every 5-20 years.
Crescent-shaped dunes are common in coastal deserts such as the Namib, Africa, with prevailing onshore winds. Low clouds cover parts of the Namib in this space shuttle photo.
High dunes of the Namib Desert near Sossus Vlei (photograph by Georg Gerster).
Morning fog moistens the dunes of the Namib coastal desert (photograph by Georg Gerster).