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Antarctica Continent

Antarctica Explanation :: --Antarctica History||Antarctica Geography||Antarctica Administration||

You are here at Antarctica Continent,This is the list of Antarctic territories ..

 

  • Size: 13,209,000 sq km, 5,100,021 sq miles 
    (varies due to changing ice shelves)
  • Percent of Earth's Land: 8.9%
  • Status Antarctica, almost 98% solid ice, was finally considered a continent in 1840, and not just a group of isolated islands. Today it has active territorial claims submitted by Argentina, Australia, Chile, France, New Zealand, Norway and the United Kingdom. (Many of these claims are not recognized by some countries and remain in a constant disputed status)
  • Capital City none
  • Climate Antarctica is the coldest and windiest spot on the planet. In fact, the lowest temperature ever recorded on Earth was recorded in Antarctica (-129.3ºF) and the mean winter temperatures range from -40º to -94ºF. Winds are commonly measured at up to 200 miles per hour.

Antarctica is Earth's southernmost continent, encapsulating the South Pole. It is situated in the Antarctic region of the Southern Hemisphere, almost entirely south of the Antarctic Circle, and is surrounded by the Southern Ocean. At 14.0 million km2 . it is the fifth-largest continent in area after Asia, Africa, North America, and South America. For comparison, Antarctica is nearly twice the size of Australia. About 98% of Antarctica is covered by ice that averages at least 1.6 kilometres in thickness.

Antarctica

Antarctica, on average, is the coldest, driest, and windiest continent, and has the highest average elevation of all the continents. Antarctica is considered a desert, with annual precipitation of only 200 mm along the coast and far less inland. The temperature in Antarctica has reached −89 °C . There are no permanent human residents, but anywhere from 1,000 to 5,000 people reside throughout the year at the research stations scattered across the continent. Only cold-adapted organisms survive there, including many types of algae, animals bacteria, fungi, plants, and protista. Vegetation where it occurs is tundra.
Although myths and speculation about a Terra Australis ("Southern Land") date back to antiquity, the first confirmed sighting of the continent is commonly accepted to have occurred in 1820 by the Russian expedition of Fabian Gottlieb von Bellingshausen and Mikhail Lazarev. The continent, however, remained largely neglected for the rest of the 19th century because of its hostile environment, lack of resources, and isolation. The Antarctic Treaty was signed in 1959 by 12 countries; to date, 47 countries have signed the treaty. The treaty prohibits military activities and mineral mining, prohibits nuclear explosions and nuclear power, supports scientific research, and protects the continent's ecozone. Ongoing experiments are conducted by more than 4,000 scientists of multiple nationalities.

 

The geography of Antarctica is dominated by its south polar location and, thus, by ice. The Antarctic continent, located in the Earth's southern hemisphere, is centered asymmetrically around the South Pole and largely south of the Antarctic Circle. It is surrounded by the southern waters of the World Ocean – alternatively (depending on source), it is washed by the Southern (or Antarctic) Ocean or the southern Pacific, Atlantic, and Indian Oceans. It has an area of more than 14 million km².

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Antarctic Circle 
The Antarctic (or Antarctica) Circle is one of the five major circles or parallels of latitude that mark maps of the Earth. 

Shown on the image above with a dashed red line, this parallel of latitude sits at approximately 66.33° south of the Equator. It marks the northern limit of the area within which, for one day or more each year, the sun does not set or rise. 

The length of continuous day or night increases southward from the Antarctic Circle, mounting to six months at the South Pole. 

  • Highest Point Vinson Massif at 16,066 ft. (4,897 m)
  • Lowest Point Bentley Subglacial Trench, -2,555 m)
  • Latitude/Longitude 90° S, 0.00° E
  • Official Language none
  • Official Currency none
  • Population Officially none, but governmental research stations are populated with small groups of scientists at all times. In addition, during the 2009/2010 season, nearly 37,000 tourists visited the continent.

 

 

Ice mass and global sea level

Due to its location at the South Pole, Antarctica receives relatively little solar radiation. This means that it is a very cold continent where water is mostly in the form of ice.

 

Precipitation is low (most of Antarctica is a desert) and almost always in the form of snow, which accumulates and forms a giant ice sheet which covers the land. Parts of this ice sheet form moving glaciers known as ice streams, which flow towards the edges of the continent.

 

Next to the continental shore are many ice shelves. These are floating extensions of outflowing glaciers from the continental ice mass. Offshore, temperatures are also low enough that ice is formed from seawater through most of the year.

antarctica map

It is important to understand the various types of Antarctic ice to understand possible effects on sea levels and the implications of global warming.
Sea ice extent expands annually in the Antarctic winter and most of this ice melts in the summer. This ice is formed from the ocean water and floats in the same water and thus does not contribute to rise in sea level. The extent of sea ice around Antarctica has remained roughly constant in recent decades, although the thickness changes are unclear.
Melting of floating ice shelves (ice that originated on the land) does not in itself contribute much to sea-level rise (since the ice displaces only its own mass of water). However it is the outflow of the ice from the land to form the ice shelf which causes a rise in global sea level. This effect is offset by snow falling back onto the continent. Recent decades have witnessed several dramatic collapses of large ice shelves around the coast of Antarctica, especially along the Antarctic Peninsula. Concerns have been raised that disruption of ice shelves may result in increased glacial outflow from the continental ice mass.
On the continent itself, the large volume of ice present stores around 70% of the world's fresh water. This ice sheet is constantly gaining ice from snowfall and losing ice through outflow to the sea. West Antarctica is currently experiencing a net outflow of glacial ice, which will increase global sea level over time. A review of the scientific studies looking at data from 1992 to 2006 suggested that a net loss of around 50 gigatonnes of ice per year was a reasonable estimate (around 0.14 mm of sea level rise).Significant acceleration of outflow glaciers in the Amundsen Sea Embayment may have more than doubled this figure for 2006.
East Antarctica is a cold region with a ground base above sea level and occupies most of the continent. This area is dominated by small accumulations of snowfall which becomes ice and thus eventually seaward glacial flows. The mass balance of the East Antarctic Ice Sheet as a whole is thought to be slightly positive (lowering sea level) or near to balance.However, increased ice outflow has been suggested in some regions.

Effects of global warming

Some of Antarctica has been warming up; particularly strong warming has been noted on the Antarctic Peninsula. A study by Eric Steig published in 2009 noted for the first time that the continent-wide average surface temperature trend of Antarctica is slightly positive at >0.05 °C per decade from 1957 to 2006. This study also noted that West Antarctica has warmed by more than 0.1 °C per decade in the last 50 years, and this warming is strongest in winter and spring. This is partly offset by fall cooling in East Antarctica. There is evidence from one study that Antarctica is warming as a result of human carbon dioxide emissions. However, the small amount of surface warming in West Antarctica is not believed to be directly affecting the West Antarctic Ice Sheet's contribution to sea level. Instead the recent increases in glacier outflow are believed to be due to an inflow of warm water from the deep ocean, just off the continental shelf. The net contribution to sea level from the Antarctic Peninsula is more likely to be a direct result of the much greater atmospheric warming there.
In 2002 the Antarctic Peninsula's Larsen-B ice shelf collapsed. Between 28 February and 8 March 2008, about 570 square kilometres of ice from the Wilkins Ice Shelf on the southwest part of the peninsula collapsed, putting the remaining 15,000 km2 of the ice shelf at risk. The ice was being held back by a "thread" of ice about 6 km wide,prior to its collapse on 5 April 2009. According to NASA, the most widespread Antarctic surface melting of the past 30 years occurred in 2005, when an area of ice comparable in size to California briefly melted and refroze; this may have resulted from temperatures rising to as high as 5 °C .

Ozone depletion

Each year a large area of low ozone concentration or "ozone hole" grows over Antarctica. This hole covers the whole continent and is at its largest in September. 2008 saw the longest lasting hole on record, which remained until the end of December. The hole was detected by scientists in 1985 and has tended to increase over the years of observation. The ozone hole is attributed to the emission of chlorofluorocarbons or CFCs into the atmosphere, which decompose the ozone into other gases.
Some scientific studies suggest that ozone depletion may have a dominant role in the recent climate changes in Antarctica (and a wider area of the Southern Hemisphere).Ozone absorbs large amounts of ultraviolet radiation in the stratosphere. Ozone depletion over Antarctica can cause a cooling of around 6 °C in the local stratosphere. This cooling has the effect of intensifying the westerly winds which flow around the continent (the polar vortex) and thus prevents outflow of the cold air near the South Pole. As a result, the continental mass of the East Antarctic ice sheet is held at lower temperatures, and the peripheral areas of Antarctica, especially the Antarctic Peninsula, are subject to higher temperatures, which promote accelerated melting.Recent models also suggest that the ozone depletion/enhanced polar vortex effect also accounts for the recent increase in sea-ice just offshore of the continent.

 

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