Geography

Antarctica's land mass covers about 15.4 million square miles (7 million km2), making it the smallest continent aside from Australia. Yet its mountains are such a significant portion of its landmass that it is the highest, on average, of all seven continents. It is also the windiest continent, the coldest continent -- and of course, the least populated continent on earth.

The most distinctive feature of Antarctica is its ice cap -- by far the largest body of ice in the world, and the largest body of fresh water, comprising nearly 70 % of the earth's total. Yet despite the enormous quantity of ice that covers the continent, the average precipitation on Antarctica is quite low -- about 2 inches per year, far less than in many desert areas. In fact, using precipitation as the measure, Antarctica is the largest desert in the world.

In general, Antarctica is described as the continent and its adjacent islands. By common definition, however -- and by international agreement under the Antarctic Treaty of 1959 -- the jurisdiction of Antarctica covers the entire region below 60 degrees South. The biological limit of Antarctica is the Antarctic Convergence, or Antarctic Polar Front. The position of this boundary is roughly equivalent to the political boundary, but varies by season and specific locale, from 60 degrees S in the vicinity of South America to 50 degrees S in the Indian Ocean, as a result from changes in winds, currents and sea conditions.
















The Circumpolar Current

The Antarctic is encircled by the Southern Ocean, which flows for the most part in an eastward direction. This global movement, known as the Circumpolar Current, is driven by the strong westerly winds that circle the world in the high latitudes. These powerful winds and depressions create some of the most tempestuous seas in the world. The high latitudes are appropriately known to sailors as the "roaring forties", "furious fifties" and "screaming sixties", and it is rare not to encounter at least one storm of mountainous proportions when sailing to and from the continent. A shallower, less powerful counter circulation known as the Eastwind Drift, immediately adjacent to the Antarctic, moves pack-ice under its influence in a westerly direction. Return


The Antarctic Convergence

The water temperatures of the Southern Ocean are far from uniform. Around 60 degrees South, where the Southern ocean meets the warmer southward flowing waters of the Atlantic, Pacific and Indian oceans, is the zone known as the Antarctic Convergence, or Polar Front. The total area of sea within the convergence makes up one tenth of all the world's oceans, and contains the coolest and densest water to be found anywhere.

A portion of this, known as Antarctic Bottom Water, spreads out over the world's ocean floors and causes the temperature of much of the deep ocean to be cooled to less than 2 degrees C. Antarctic Bottom Water is rich in oxygen. The cold moderates much of the earth's climate by counter-balancing the heating effect of the tropics.

Within the boundaries of the Southern Ocean, the east-flowing currents have a complex vertical circulation which draws water rich in nutrients to the surface. These nutrients are the basis for the highly productive nature of the southern seas. As well as being rich in marine life, the Southern Ocean plays a complex role in the formation of weather patterns of the continent. Return


The Highest Continent

Antarctica is also the highest continent in the world, with an estimated average altitude of 7500 feet (2300 m). Asia, by comparison, has an average height of only about 2900 feet (900 m) in spite of the presence of Mount Everest and the mighty Himalaya.

The tallest mountain in Antarctica is the Vinson Massif in the Sentinel Range, which towers 16,067 feet (4897 m) above sea-level. The peak was established as the highest by an American traverse party in 1957 and named by them after Carl Vinson, the chairman of the U.S. House Armed Services Committee. Vinson Massif was first climbed in December 1966 by an American expedition. In summer the peak is a popular destination for mountaineers many of whom are attempting to climb the highest points on all seven continents. Return
Photography ©Jonathan Chester, Extreme Images© 1995 Terraquest. All Rights Reserved.