About the Atacama
The Atacama Desert (Spanish: Desierto de Atacama) is a plateau in South America, covering a 1,000-kilometre (600 mile) 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 kilometres 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 average rainfall in the Chilean region of the Atacama Desert is .004 inches per year, meaning it gets 4 inches of rain in a thousand years. 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.
The desert 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. Geographically, the aridity can be explained by the following reasons:
· The desert is located on the leeward side of the Chilean Coast Range, so little moisture from the Pacific Ocean can reach the desert.
· The Andes are so high that they block convective clouds, which might bring precipitation, formed above the Amazon Basin from entering the desert from the east.
· An inversion layer is created by the cold Humboldt current and the South Pacific High.
· The rain that would change the climate of the land mostly falls at sea instead. Largely this is caused by the cold waters of the Humboldt current just off shore. The temperature change causes most of the clouds and the rain to occur over the ocean instead of over the land. The Humboldt Current transports cold water from Antarctica towards the north the length of the Chilean and Peruvian coasts; this water that makes the western sea breezes cold, reducing evaporation and creating a thermic inversion (cold air immobilized under a cover of tepid air) which prevents the formation of large, rain-producing clouds.
Comparisons to Mars
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. The team duplicated the Viking tests in Mars-like Earth environments and found that they missed present signs of life in soil samples from Antarctic dry valleys, the Atacama Desert of Chile and Peru, and other locales.
In 2008, the Phoenix Mars Lander detected perchlorates on the surface of Mars at the same site where water was first discovered. Perchlorates are also found in the Atacama Desert and associated nitrate deposits have contained organics, leading to speculation that signs of life on Mars are not incompatible with perchlorates. The Atacama is also a testing site for the NASA-funded Earth-Mars Cave Detection Program.Movie Connections
The unique geography offered by the Atacama Desert is such that it has been chosen as a location for scenes in many movies. These include The Motorcycle Diaries (2004), Spy Kids (2001) with the most notable being James Bond’s Quantum of Solace (2008). In Quantum of Solace, the final scenes bring James Bond to Bolivia but in reality the ‘Bolivian’ village is Baquedano is actually located in the Atacama Desert in Chile. (Baquedano is about 50 miles northeast of the coastal city of Antofagasta in northern Chile.) James Bond’s nemesis in the movie is a character called Dominic Greene and his ‘Bolivian’ desert hideout is the Residencia. The Residencia houses accommodation for the Paranal Observatory of the ESO (European Southern Observatory), in the desert about 75 miles south of Antofagasta in northern Chile.
Quantum of Solace – James Bond leaves Mr. Greene in the Atacama Desert