Demény István: Dél-Amerika és az Antarktisz-félsziget (2008) / 1060-2008

Port Lockroy Museum. The Blue ice covering Lake Fryxell, in the Transantarctic Mountains, comes from glacial meltwater from the Canada Glacier and other smaller glaciers. is a frozen desert with little precipitation; the South Pole itself receives almost none. Temperatures reach a minimum of between -85 °C and -90 °C (-121 °F and -130 °F) in the winter and about 20 °C (30 °F) higher in the summer months. Sunburn is often a health issue as the snow surface reflects over 90% of the sunlight falling on it.'

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2! Eastern Antarctica is colder than its western counterpart because of higher elevation. Weather fronts rarely penetrate far into the continent, leaving the center cold and dry. Despite the lack of precipitation over the central portion of the continent, ice there lasts for extended time periods. Heavy snowfalls are not uncommon on the coastal portion of the continent, where snowfalls of up to 1.22 meters (48 inches) in 48 hours have been recorded. At the edge of the continent, strong katabatic winds off the polar plateau often blow at storm force. In the interior, however, wind speeds are typically moderate. During summer more solar radiation reaches the surface at the South Pole than is received at the equator in an equivalent period.'

2^ Antarctica is colder than the Arctic for two reasons. First, much of the continent is more than 3 km above sea level, and temperature decreases with elevation. Second, the Arctic Ocean covers the north polar zone: the ocean's relative warmth is transferred through the icepack and prevents temperatures in the Arctic regions from reaching the extremes typical of the land surface of Antarctica. Mountain glaciation. Given the latitude, long periods of constant darkness or constant sunlight create climates unfamiliar to human beings in much of the rest of the world. The aurora australis, commonly known as the southern lights, is a glow observed in the night sky near the South Pole. Another unique spectacle is diamond dust, a ground-level cloud composed of tiny ice crystals. It generally forms under otherwise clear or nearly clear skies, so people sometimes also refer to it as clear-sky precipitation. A sun dog, a frequent atmospheric optical phenomenon, is a bright "spot" beside the true sun.'

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2' Population See also: Demographics of Antarctica Antarctica has no permanent residents, but a number of governments maintain permanent research stations throughout the continent. The number of people conducting and supporting scientific research and other work on the continent and its nearby islands varies from approximately 4000 in summer to 1000 in winter. Many of the stations are staffed year-round. The first semi-permanent inhabitants of regions near Antarctica (areas situated south of the Antarctic Convergence) were English and American sealers who used to spend a year or more on South Georgia, from 1786 onward. During the whaling era, which lasted until 1966, the population of that island varied from over 1000 in the summer (over 2000 in some years) to some 200 in the winter. Most of the whalers were Norwegian, with an increasing proportion of Britons. The settlements included Grytviken, Leith Harbour, King Edward Point, Stromness, Husvik, Prince Olav Harbour, Ocean Harbour and Godthul. Managers and other senior officers of the whaling stations often lived together with their families. Among them was the founder of Grytviken, Captain Carl Anton Larsen, a prominent Norwegian whaler and explorer who adopted British citizenship in 1910, and his family.