Archive

Posts Tagged ‘Travel’

Salar de Uyuni

From Wikipedia, the free encyclopedia

Location of Salar de Uyuni

Salar de Uyuni viewed from space, with Salar de Coipasa in the top left corner.

Salar de Uyuni (or Salar de Tunupa) is the world’s largest salt flat at 10,582 square kilometers (4,086 sq mi). It is located in the Potosí and Oruro departments in southwest Bolivia, near the crest of the Andes, and is elevated 3,656 meters (11,995 ft) above mean sea level.[1] The Salar was formed as a result of transformations between several prehistoric lakes. It is covered by a few meters of salt crust, which has an extraordinary flatness with the average altitude variations within one meter over the entire area of the Salar. The crust serves as a source of salt and covers a pool of brine, which is exceptionally rich inlithium. It contains 50 to 70% of the world’s lithium reserves,[2] which is in the process of being extracted. The large area, clear skies and exceptional surface flatness make the Salar an ideal object for calibrating the altimeters of the Earth observation satellites.[3][4][5][6][7] The Salar serves as the major transport route across the Bolivian Altiplano and is a major breeding ground for several species of pink flamingos. Salar de Uyuni is also a climatological transitional zone, for towering tropical cumulus congestus and cumulus incus clouds that form in the eastern part of the massive salt flat during summer, cannot permeate beyond the salt flat’s considerably more arid western edges, near the Chilean border and the Atacama Desert.

Contents

[hide]

Formation, geology and climate

The salar is composed of various layers of salt and water.

Salar de Uyuni is part of the Altiplano of Bolivia in South America. The Altiplano is a high plateau, which was formed during uplift of the Andes mountains. The plateau includes fresh and saltwater lakes as well as salt flats and is surrounded by mountains with no drainage outlets.[8]

The geological history of the Salar is associated with a sequential transformation between several vast lakes. Some 30,000–42,000 years ago, the area was part of a giant prehistoric lake, Lake Minchin. Its age was estimated from radiocarbon dating of shells from outcropping sediments and carbonate reefs and varies between reported studies. Lake Minchin (named after the Juan B. Minchin of Oruro[9]) later transformed into paleolake Tauca having a maximal depth of 140 meters (460 ft), and an estimated age of 13,000–18,000 or 14,900–26,100 years depending on the source. The youngest prehistoric lake was Coipasa, which was radiocarbon dated to 11,500–13,400 years. When it dried, it left behind two modern lakes, Poopó Lake and Uru Uru Lake, and two major salt deserts, Salar de Coipasa and the larger Salar de Uyuni. Salar de Uyini spreads over 10,582 square kilometers (4,086 sq mi), which is roughly 25 times the size of the Bonneville Salt Flats in the United States. Lake Poopó is a neighbor of the much larger lake Titicaca. During the wet season, Titicaca overflows and discharges into Poopó, which, in turn, floods Salar De Coipasa and Salar de Uyuni.[10]

Underneath the surface of the Salar is a lake of brine 2 to 20 meters (7 to 66 ft) deep. The brine is a saturated solution of sodium chloridelithium chloride and magnesium chloride in water. It is covered with a solid salt crust with a thickness varying between tens of centimeters to a few meters. The center of the Salar contains a few “islands”, which are the remains of the tops of ancient volcanoes which were submerged during the era of lake Minchin. They include unusual and fragile coral-like structures and deposits that often consist of fossils and algae.[11]

The area has a relatively stable average temperature with a peak at 21 °C (70 °F) in November–January and a low of 13 °C (55 °F) in June. The nights are however cold all through the year with temperatures between -9 and 5 °C (16 and 41 °F). The relative humidity is rather low and constant throughout the year at 30–45 %. The rainfall is also low at 1–3 millimeters (0.039–0.12 in) per month between April and November, but it may increase up to 70 millimeters (2.8 in) in January. However, except for January, even in the rainy season the number of rainy days is below 5 per month.[7]

Incahuasi Island in the center of the Salar

Economic influence

Salt production at the Salar

The Salar contains large amounts of sodiumpotassiumlithium and magnesium (all in the chloride forms of NaCl, KCl, LiCl and MgCl2, respectively), as well as borax.[11] Of those, lithium is arguably most important as it is a vital component of many electric batteries. With estimated 9,000,000 tonnes (8,900,000 long tons; 9,900,000 short tons), Bolivia holds about 43% of the world’s lithium reserves;[12] most of those are located in the Salar de Uyuni. Lithium is concentrated in the brine under the salt crust at a relatively high concentration of about 0.3%. It is also present in the top layers of the porous halite body lying under the brine; however the liquid brine is easier to extract, by boring into the crust and pumping out the brine.[13] The brine distribution has been monitored by the Landsat satellite and confirmed in ground drilling tests. Following those findings, an American-based international corporation has invested $137 million to develop lithium extraction.[14] However, lithium extraction in the 1980s and 1990s by foreign companies met strong opposition of the local community. Despite their poverty, locals believed that the money infused by mining would not reach them. There is currently no mining plant at the site, and the Bolivian government doesn’t want to allow exploitation by foreign corporations. Instead, it intends to build its own pilot plant with a modest annual production of 1,200 tonnes (1,200 long tons; 1,300 short tons) of lithium and to increase it to 30,000 tonnes (30,000 long tons; 33,000 short tons) tonnes by 2012.[15]

Salar de Uyuni is estimated to contain 10 billion tonnes (9.8 billion LT; 11 billion ST) of salt, of which less than 25,000 tonnes (25,000 long tons; 28,000 short tons) is extracted annually. All miners working in the Salar belong to Colchani’s cooperative.

Because of its location, large area and flatness, the Salar is a major car transport route across the Bolivian Altiplano.[8]

Name

Salar is salt flat in Spanish and Uyuni originates from the Aymara language and means a pen (enclosure). Thus Salar de Uyuni can be loosely translated as a salt flat with enclosures, the latter possibly referring to the “islands” of the Salar. Uyuni is also the name for a town of 10,600 people, which serves as a gateway for tourists visiting the Salar.

Aymara legend tells that the mountains Tunupa, Kusku and Kusina, which surround the Salar, were giant people. Tunupa married Kusku, but Kusku ran away from her with Kusina. Grieving Tunupa started to cry while breast-feeding her son. Her tears mixed with milk and formed the Salar. Many locals consider the Tunupa an important deity and say that the place should be called Salar de Tunupa rather than Salar de Uyuni.[11]

Flora and fauna

The Salar is virtually devoid of any wild life and vegetation. The latter is dominated by giant cacti (Echinopsis atacamensis pasacanaEchinopsis tarijensis, etc.). They grow at a rate of about 1 centimeter (0.39 in) per year to a length of about 12 meters (39 ft). Other shrubs include Pilaya, which is used by locals to cure catarrh, and Thola (Baccharisdracunculifolia), which is burned as a fuel. Also present are quinoa plants and quenua bushes.[11]

Every November, Salar de Uyuni is the breeding grounds for three species of pink South American flamingos: the ChileanAndean and rare James’s Flamingos, their color presumably originating from feeding on pink algae. There are about 80 of other bird species present, including the horned coot, the Andean goose and the Andean Hillstar. Andean fox (culpeo) is a representative animal, and the “islands” of Salar (in particular the Incahuasi island, which is also called Isla del Pescadores) host a colony of rabbit-like viscachas.[11]

Tourism

Hotels

Traditional salt production at Salar. Such salt blocks are used for building salt hotels.

See also: Palacio de Sal

Salar de Uyuni attracts tourists from around the world. As it is located far from the cities, a number of hotels have been built in the area. Due to lack of conventional construction materials, many of them are almost entirely (walls, roof, furniture) built with salt blocks cut from the Salar. The first such hotel was erected in 1993-1995[16][17] in the middle of the salt flat,[18][19] and soon became a popular tourist destination.[20] However, its location in the center of a desert produced sanitary problems, as most waste had to be collected manually. Mismanagement caused serious environmental pollution and the hotel had to be dismantled in 2002.[21][22] New salt hotels were built near the periphery of the Salar, closer to roads, in full compliance with environmental rules.

Train cemetery

One major tourist attraction is an antique train cemetery. It is 3 kilometers (1.9 mi) outside Uyuni and is connected to it by the old train tracks. The town served in the past as a distribution hub for the trains carrying minerals enroute to Pacific Ocean ports. The rail lines were built by British engineers arriving near the end of the 19th century and formed a sizeable community in Uyuni. The engineers were invited by British-sponsored Antofagasta and Bolivia Railway Companies, which is now Ferrocarril de Antofagasta a Bolivia. The rail construction started in 1888 and ended in 1892. It was encouraged by Bolivian President Aniceto Arce, who believed Bolivia would flourish with a good transport system, but it was also constantly sabotaged by the local Aymara indigenous Indians who saw it as an intrusion into their lives. The trains were mostly used by the mining companies. In the 1940s, the mining industry collapsed, partly because of mineral depletion. Many trains were abandoned, producing the train cemetery. There are proposals to build a museum from the cemetery.[11]

Cemetery of trains near the town of Uyuni.

Satellite calibration

When covered with water, the Salar becomes one of the largest mirrors on Earth.

Dried surface of the Salar.

Salt flats are ideal for calibrating the distance measurement equipment of satellites because they are large, stable surfaces with strong reflection, similar to that of ice sheets. As the largest salt flat on Earth, Salar de Uyuni is especially suitable for this purpose. In the low-rain period of from April to November, due to the absence of industry and its high elevation the skies above Salar de Uyuni are very clear, and the air is dry (relative humidity is about 30%, rainfall is roughly 1 millimetre or 0.039 inches per month). It has a stable surface which is smoothed by seasonal flooding (water dissolves the salt surface and thus keeps it leveled). As a result, the variation in the surface elevation over the 10,582-square-kilometer (4,086 sq mi) area of Salar de Uyuni is less than 1 meter (3 ft 3 in), and there are few square kilometers on Earth which are as flat. The surface reflectivity (albedo) for ultraviolet light is relatively high at 0.69 and shows variations of only a few percent during the daytime.[6] The combination of all these features makes Salar de Uyuni about five times better for satellite calibration than the surface of an ocean.[4][5][23] Using Salar de Uyuni as the target, ICESat has already achieved the short-term elevation measurement accuracy of below 2 centimeters (0.79 in).[24]

With the use of modern GPS technology, it can now be proved that the Salar de Uyuni is not perfectly flat. New measurements revealed previously missed features resembling ridges, hills, and valleys measuring only millimeters in height. They originate from the variation in material density, and thus the gravitational force, beneath the Salar’s sediments. Just as the ocean surface rises over denser seamounts, the salt flat surface also rises and falls to reflect the subsurface density variations.[23][25]

References

  1. ^ “Uyuni Salt Flat”. Encyclopædia Britannica. Retrieved 2007-12-01.
  2. ^ Keating, Joshua (2009-10-21). “Bolivia’s Lithium-Powered Future: What the global battery boom means for the future of South America’s poorest country.”Foreign Policy.
  3. ^ Borsa, A. A; et al. (2002). “GPS Survey of the salar de Uyuni, Bolivia, for Satellite Altimeter Calibration”. American Geophysical Union, Fall Meeting.
  4. a b Hand, Eric (2007-11-30). “The salt flat with curious curves”Nature.
  5. a b Fricker, H. A. (2005). “Assessment of ICESat performance at the salar de Uyuni, Bolivia” (free download pdf). Geophysical Research Letters 32 (21): L21S06. Bibcode 2005GeoRL..3221S06F.doi:10.1029/2005GL023423.
  6. a b Reuder, Joachim et al (2007). “Investigations on the effect of high surface albedo on erythemally effective UV irradiance: Results of a campaign at the Salar de Uyuni, Bolivia” (free-download pdf). Journal of Photochemistry and Photobiology B 87 (1): 1–8.doi:10.1016/j.jphotobiol.2006.12.002PMID 17227712.
  7. a b Lamparelli, R. A. C. et al (2003). “Characterization of the Salar de Uyuni for in-orbit satellite callibration”. IEEE Trans. Geosci. Remote Sens. 41 (6): 1461–1468.doi:10.1109/TGRS.2003.810713.
  8. a b “Salar de Uyuni, Bolivia”NASA Earth Observatory. Retrieved 2007-12-01.
  9. ^ Isaiah Bowman Results of an Expedition to the Central Andes, Bulletin of the American Geographical Society, Vol. 46, No. 3 (1914), pp. 161
  10. ^ Baker, P. A. et al (2001). “Tropical climate changes at millennial and orbital timescales on the Bolivian Altiplano”.Nature 409 (6821): 698–701. doi:10.1038/35055524.PMID 11217855.
  11. a b c d e f Atkinson, David (2007-03-01). Bolivia: The Bradt Travel Guide. Bradt Travel Guides. pp. 170; 174–176.ISBN 978-1-84162-165-4.
  12. ^ “Lithium”. USGS.
  13. ^ “In search of Lithium: The battle for the 3rd element”. Dailymail. 5 April 2009.
  14. ^ National Research Council (U.S.). Board on Science and Technology for International Development, National Research Council (U.S.). Office of International Affairs (1988). Science and technology for development: prospects entering the twenty-first century : a symposium in commemoration of the twenty-fifth anniversary of the U.S. Agency for International Development. National Academies. p. 60.
  15. ^ “Bolivia holds key to electric car future”. BBC. 2008-11-09.
  16. ^ “Bolivian Hotel Truly Is the Salt of the Earth”. January 27, 2009.
  17. ^ “Don’t Lick the Walls of the Salt Hotel”. 19 May 2009.
  18. ^ McFarrren, Peter (1999-03-04). “Salt hotel has a rule: No licking”. The Associated Press.
  19. ^ Box, Ben; Robert Kunstaetter, Daisy Kunstaetter, Geoffrey Groesbeck (2007). Peru, Bolivia & Ecuador. Footprint Travel Guides. pp. 378. ISBN 1-906098-06-9.
  20. ^ “Photo in the News: New Salt Hotel Built in Bolivia”. National Geographic. 2007-07-25. Retrieved 2009-09-01.
  21. ^ Adès, Harry (2004). The Rough Guide to South America. Rough Guides. pp. 259. ISBN 1-85828-907-6.
  22. ^ “Palacio del Sal” (in German).
  23. a b “The Hills And Valleys Of Earth’s Largest Salt Flat”. GPS Daily. 2007-11-29.
  24. ^ Spreen, Gunnar (2008). Satellite-based Estimates of Sea Ice Volume Flux: Applications to the Fram Strait Region. GRIN Verlag. p. 22. ISBN 3-640-13064-2.
  25. ^ Bills, Bruce G. et al (2007). “MISR-based passive optical bathymetry from orbit with few-cm level of accuracy on the Salar de Uyuni, Bolivia”. Remote Sensing of Environment 107(1–2): 240–255. doi:10.1016/j.rse.2006.11.006.

Gallery

Panoramic view of the Salar

Wikimedia Commons has media related to: Salar de Uyuni
  • The Salar de Uyuni reflecting a sunset.

  • Piles of salt at the Salar

  • Llamas in the Salar

Advertisements
Categories: Travel Tags: ,

卫星照片:全球最繁忙的国际机场

April 22, 2012 Leave a comment

Via 天涯-贴图专区

1哈兹菲尔德-杰克逊亚特兰大国际机场 Hartsfield–Jackson Atlanta International Airport 92,365,860 ATL/KATL


2北京首都国际机场 Beijing Capital International Airport 77,403,668 PEK/ZBAA


3 伦敦希思路机场 London Heathrow Airport 69,433,565 LHR/EGLL


4芝加哥奥黑尔国际机场 O’Hare International Airport 66,561,023 ORD/KORD


5日本羽田国际机场 Tokyo International Airport 62,263,025 HND/RJTT


6 洛杉矶国际机场 Los Angeles International Airport 61,848,449 LAX/KLAX


7巴黎-夏尔?戴高乐机场 Paris Charles de Gaulle Airport 60,970,551 CDG/LFPG


8达拉斯-沃思堡国际机场 Dallas Fort Worth International Airport 57,806,152 DFW/KDFW


9德国法兰克福国际机场 Frankfurt Airport 56,436,255 FRA/EDDF


10香港国际机场 Hong Kong International Airport 53,314,213 HKG/VHHH


11丹佛国际机场 Denver International Airport 52,699,298 DEN/KDEN


12印尼苏加诺-哈达国际机场 Soekarno-Hatta International Airport 52,446,618 CGK/WIII


13阿联酋迪拜国际机场 Dubai International Airport 50,977,960 DXB/OMDB


14荷兰史基浦机场 Amsterdam Schiphol Airport 49,754,910 AMS/EHAM


15西班牙马德里-巴拉哈斯机场 Madrid Barajas Airport 49,644,302 MAD/LEMD


16泰国素万那普机场 Suvarnabhumi Airport 47,910,744 BKK/VTBS


17纽约约翰?菲茨杰拉德?肯尼迪国际机场 John F. Kennedy International Airport 47,854,283 JFK/KJFK


18新加坡樟宜机场 Singapore Changi Airport 46,543,845 SIN/WSSS


19拉斯维加斯麦卡伦国际机场 McCarran International Airport 41,479,572 LAS/KLAS


20上海浦东国际机场 Shanghai Pudong International Airport 41,450,211 PVG/ZSPD

  21旧金山国际机场 San Francisco International Airport 40,907,389 SFO/KSFO


22菲尼克斯天港国际机场 Phoenix Sky Harbor International Airport 40,565,677 PHX/KPHX


23休斯顿乔治?布什洲际机场 George Bush Intercontinental Airport 40,170,844 IAH/KIAH


24夏洛特/道格拉斯国际机场 Charlotte Douglas International Airport 39,043,708 CLT/KCLT


25迈阿密国际机场 Miami International Airport 38,314,389 MIA/KMIA

  26德国慕尼黑机场 Munich Airport 37,763,701 MUC/EDDM


27马来西亚吉隆坡国际机场 Kuala Lumpur International Airport 37,670,586 KUL/WMKK


28意大利罗马-菲乌米奇诺机场 Leonardo da Vinci-Fiumicino Airport 37,651,222 FCO/LIRF


29土耳其阿塔蒂尔克国际机场 Atatürk International Airport 37,398,221 IST/LTBA


30 澳大利亚悉尼金斯福德?史密斯国际机场 Sydney Airport 36,022,614 SYD/YSSY

Categories: Travel Tags: , ,
%d bloggers like this: