Atacama

(in Indian—desert area), a desert in northern Chile, on the western slopes of the Andes. It is about 1,000 km long and includes the coastal cordillera—with elevations of up to 3,200 m—the longitudinal valley, and the western slopes of the Cordillera de Domeyko—with elevations to 4,325 m. Atacama belongs to the category of so-called coastal deserts, which form under the influence of the outlying eastern area of subtropical anticyclones. Its climate is a tropical trade-wind climate and is relatively cool because of the effects of the cold Peruvian current. On the coast the average January temperature is about 20°C, and the average July temperature is about 13° C. Precipitation, which does not occur every year, averages less than 50 mm per year. The spring and winter relative humidity on the coast reaches 82 percent; cloudiness reaches 85 percent. At elevations of up to 600 m, fog (camanchaca) and light drizzle (garua) are typical. Occasional water currents from the Andes dry up or are channeled off for irrigation; only the Loa River reaches the ocean.

The surface of the Atacama is primarily covered with moving sands, detritus, and saline soils. The coastal strip becomes covered with loma-type temporary vegetation during periods of fog. On coastal cliffs and islets there are seashore bird colonies and deposits of guano. On the eastern foot of the coastal cordillera there are unique deposits of sodium and potassium nitrates, borax, iodine, and common salt. The largest deposits of copper in the capitalist world— Chuquicamata, El Salvador, and others—are located on the western slopes of the Andes.