Antarctic Convergence
The Antarctic Convergence or Antarctic Polar Front is a marine belt encircling Antarctica, varying in latitude seasonally, where cold, northward-flowing Antarctic waters meet the relatively warmer waters of the sub-Antarctic. The line separates the clockwise Antarctic circumpolar current from other oceans. [1] Antarctic waters predominantly sink beneath the warmer subantarctic waters, while associated zones of mixing and upwelling create a zone very high in marine productivity, especially for Antarctic krill.
This line, like the Arctic tree line, is a natural boundary rather than an artificial one, such as the borders of nations and time zones. It not only separates two hydrological regions, but also separates areas of distinctive marine life and climates.
The Arctic has no similar boundary because of the large bodies of land contiguous with the northern polar region.
History
The Antarctic Convergence was first crossed by Anthony de la Roché in 1675[2] and Edmond Halley in 1700,[3] and first described by the British Discovery Investigations and the German Meteor Expedition in 1925–1927.[4]
Location
The Antarctic Convergence is a zone approximately Template:Convert wide, varying in latitude seasonally and in different longitudes, extending across the Atlantic, Pacific, and Indian oceans between the 48th and 61st parallels of south latitude. Although the northern boundary varies, for the purposes of the Convention on the Conservation of Antarctic Marine Living Resources 1980, it is defined as "50°S, 0°; 50°S, 30°E; 45°S, 30°E; 45°S, 80°E; 55°S, 80°E; 55°S, 150°E; 60°S, 150°E; 60°S, 50°W; 50°S, 50°W; 50°S, 0°."[5] Although this zone is a mobile one, it usually does not stray more than half a degree of latitude from its mean position. The precise location at any given place and time is made evident by the sudden drop in seawater temperature from north to south of, on average, Template:Convert from Template:Convert to below Template:Convert.
Subantarctic islands lying north of the Convergence
- Template:Flagdeco Amsterdam Island (France)
- Template:Flagdeco Crozet Islands (France)
- Template:Flagdeco Diego Ramírez Islands (Chile)
- Template:Country data Falkland Islands (Argentina)
- Template:Flagdeco Isla de los Estados (Argentina)
- Template:Flagdeco Macquarie Island (Australia)
- Template:Flagdeco NZ Subantarctic Islands (New Zealand)
- Template:Flagdeco Chatham Islands (New Zealand)
- Template:Flagdeco Prince Edward Islands (South Africa)
- Template:Flagdeco Saint Paul Island (France)
- Template:Flagdeco / Template:Flagdeco Tierra del Fuego (Argentina / Chile)
- Template:Country data Tristan da Cunha (United Kingdom)
Islands which lie to the south of the Convergence
North of 60°S latitude
- Template:Country data Bouvet Island (Norway)
- Template:Country data Heard Island and McDonald Islands (Australia)
- Template:Flagdeco Kerguelen Islands (France)
- Template:Country data South Georgia and the South Sandwich Islands (Argentina)
South of 60°S latitude
- Template:Flagdeco Balleny Islands (Antarctic Treaty System)
- Template:Flagdeco Peter I Island (Antarctic Treaty System)
- Template:Flagdeco Scott Island (Antarctic Treaty System)
- Template:Flagdeco South Orkney Islands (Antarctic Treaty System)
- Template:Flagdeco South Shetland Islands (Antarctic Treaty System)
See also
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- Anthony de la Roché
- Antarctic
- Antarctic Circle
- Antarctic Circumpolar Wave
- Polar front
- Southern Ocean
References
External links
Template:Antarctica Script error: No such module "Navbox".
- ↑ Script error: No such module "citation/CS1".
- ↑ R.K. Headland, The Island of South Georgia, Cambridge University Press, 1984.Template:ISBN?Template:Page?
- ↑ Alan Gurney, Below the Convergence: Voyages Toward Antarctica, 1699–1839, Penguin Books, New York, 1998.Template:ISBN?Template:Page?
- ↑ Headland, Robert Keith. (2009). A Chronology of Antarctic Exploration. London: Bernard Quaritch. 716 pp. / Extract
- ↑ Convention on the Conservation of Antarctic Marine Living Resources 1980, Article 1(4).