The Atacama Desert is a plateau in
South America, covering a 1,000-kilometre (600 mi) strip of land on the
Pacific coast, west of the
Andes mountains. It is, according to
NASA,
National Geographic and other sources, the driest desert in the world. The
Atacama occupies 105,
000 square kilometres (41,000 sq mi) composed mostly of salt lakes (salares), sand, and felsic lava flows towards the
Andes. The Atacama Desert ecoregion, as defined by the
World Wide Fund for Nature (
WWF), extends from a few kilometers south of the Peru--Chile border to about 30° south latitude. To the north lies the
Peruvian Sechura Desert ecoregion, whilst to the south is the
Chilean Matorral ecoregion.
The National Geographic Society, by contrast, considers the coastal area of southern
Peru to be part of the
Atacama Desert. It includes in this definition the deserts south of the
Ica Region in Peru. To the east lies the less arid
Central Andean dry puna ecoregion. The drier portion of this ecoregion is located south of the Loa
River between the parallel
Sierra Vicuña Mackenna and
Cordillera Domeyko. To the north of the Loa lies the
Pampa del Tamarugal. The Atacama Desert is commonly known as the driest place in the world, especially the surroundings of the abandoned Yungay town (in
Antofagasta Region,
Chile). The rainfall in the
Chilean region of the Atacama Desert is between
1 millimetre (0.04 in) and 15 millimetres (0.59 in) per year, with an average of 50 millimetres (1.97 in) per year. Some weather stations in the Atacama have never received rain.
Periods of up to four years have been registered with no rainfall in the central sector, delimited by the cities of
Antofagasta, Calama and
Copiapó, in Chile.
Evidence suggests that the Atacama may not have had any significant rainfall from 1570 to
1971. It is so arid that mountains that reach as high as 6,885 metres (22,589 ft) are completely free of glaciers and, in the southern part from 25°S to 27°S, may have been glacier-free throughout the
Quaternary, though permafrost extends down to an altitude of 4,
400 metres (14,400 ft) and is continuous above 5,
600 metres (18,400 ft). Studies by a group of
British scientists have suggested that some river beds have been dry for
120,000 years. However, some locations in the Atacama receive a marine fog known locally as the camanchaca, providing sufficient moisture for hypolithic algae, lichens and even some cacti the genus Copiapoa is notable among these. In July
2011, an extreme
Antarctic cold front broke through the rain shadow, bringing 80 centimetres (31 in) of snow to the plateau, stranding residents across the region, particularly in
Bolivia, where many drivers became stuck in snow drifts and emergency crews became overtaxed with a large number of rescue calls. This phenomenon is called the altiplano winter, which can produce a little rain and abundant electrical storms, and occurs in January and February. In
2012, the altiplano winter saw floods in
San Pedro de Atacama. At night the temperature fluctuates to as low as −25°C in the zone of Ollagüe, while during the day the temperature can be between 25--30°C in the shade.
The difference between the summer and the winter is minimal, because it is situated at the border of the tropic of
Capricorn. In summer, the morning ambient temperature is 4--10°C and the maximum it reaches is 45°C which is full solar radiation.[citation needed] The solar radiation is very high in the ultraviolet spectrum, making the use of glasses and UV sunscreens indispensable. The relative humidity in the air is about 18% in the interior, but very high near the coast, reaching up to 98% during the winter months. The atmospheric pressure is 1017 millibars. There are seasonal tornado-like winds or blizzards whose velocity can easily reach
100 km/h, generally registered at midday. The topography of the zone slopes downwards gradually towards the sea, but its average relative height is 400--1500 meters above sea level. In a region about
100 kilometres (60 mi) south of Antofagasta, which averages
3,000 metres (10,000 ft) height, the soil has been compared to that of
Mars. Owing to its otherworldly appearance, the Atacama has been used as a location for filming Mars scenes, most notably in the television series
Space Odyssey:
Voyage To
The Planets. In
2003, a team of researchers published a report in the journal
Science in which they duplicated the tests used by the
Viking 1 and Viking 2 Mars landers to detect life, and were unable to detect any signs in Atacama Desert soil. The region may be unique on
Earth in this regard and is being used by NASA to test instruments for future Mars missions.
- published: 03 Jul 2013
- views: 1327