Atacama Desert

Article By:

Wikle, Thomas A. Department of Geography, Oklahoma State University, Stillwater, Oklahoma.

Last reviewed:March 2022

DOI:https://doi.org/10.1036/1097-8542.058300

Show previous versions

• Hyperaridity and the dry limits of life, published June 2016:Download PDF Get Adobe Acrobat Reader

Earth's oldest desert and the most arid place outside of Antarctica's Dry Valleys. Located along the edge of the Pacific Ocean and to the west of the Andes in Chile's Antofagasta Province, the Atacama Desert (Fig. 1) has long been recognized as among the Earth's driest locations, with some locations having never reported precipitation. Intense solar radiation, broad temperature fluctuations, and a thin atmosphere contribute to the Atacama being characterized as close to, or perhaps beyond the dry limits of life for living organisms. Though they are often depicted as hot and barren landscapes, the common element of all arid regions is low precipitation. In classifying aridity, the index p/PET is often applied using a sliding scale based on temperature and moisture, where p = precipitation and PET = potential evapotranspiration, as determined by solar radiation, atmospheric humidity, and wind. Hyperarid (extremely dry) regions such as the Atacama receive less than 200 mm of annual rainfall and have a p/PET of less than 0.05. In comparison, southern Africa's Kalahari Desert receives about 250 mm of precipitation each year, and the Mojave Desert, located in the U.S. Southwest, receives about 350 mm of annual precipitation. Another distinguishing feature of the Atacama is its temperature. In comparison to hot deserts, such as North Africa's Sahara or the Kalahari, the Atacama is relatively cold, with temperatures ranging from 0 to 25°C. See also: Antarctica; Desert; Kalahari Desert; Pacific Ocean; South America

The content above is only an excerpt.