Antarctic Convergence
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The Antarctic Convergence, also known as the Antarctic Polar Frontal Zone, is a line encircling Antarctica where the cold, northward-flowing Antarctic waters sink beneath the relatively warmer waters of the sub-Antarctic. The line is actually a zone approximately 20 to 30 miles wide, varying somewhat in latitude in different longitudes, extending across the Atlantic, Pacific, and Indian Oceans between the 48th and 61st parallels of south latitude. The precise location at any given place and time is made evident by the sudden change in surface temperature, which averages 5 to 10 degrees Fahrenheit (2.8° C to 5.5° C). Although this zone is a mobile one, it usually does not stray more than a half a degree of latitude from its mean position.
This line, like the tree line of the north, is a natural boundary rather than one derived from reasoning. It not only separates two hydrological regions, but also separates areas of distinctive marine life associations and of different climates. The South Shetland Islands, South Orkney Islands, South Sandwich Islands, South Georgia, Bouvetoya, Heard Island and McDonald Islands all lie south of the Antarctic Convergence. The Iles Kerguelen lie approximately on the Convergence; the Falkland Islands, Prince Edward Islands, Iles crozet and Macquarie Island lie north of the Convergence.
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- This article is based on a United States Geological Survey gazetteer.
