Antarctic Convergence

Antarctic Convergence

The Antarctic Convergence, better known as the Antarctic Polar Front (or "Polar Front" for short), is a curve continuously encircling Antarctica where cold, northward-flowing Antarctic waters meet and mix with the relatively warmer waters of the sub-Antarctic. Antarctic waters predominantly sink beneath sub-Antarctic waters, while associated zones of mixing and upwelling create a zone very high in marine productivity, especially for Antarctic krill. The Polar Front is actually a zone approximately 32 to 48 km (20 to 30 mi) wide, varying somewhat in latitude seasonally and 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 drop in temperature from north to south of, on average, 2.8 °C (37 °F) to 5.5 °C (42 °F), to below 2 °C (36 °F). Although this zone is a mobile one, it usually does not stray more than a half a degree of latitude from its mean position.

The zone north of the Polar Front is called the Polar Frontal Zone; its northern boundary is the Subantarctic Front. Both the Polar Front and the Subantarctic Front are strong eastward currents that are part of the Antarctic Circumpolar Current.

There is no Arctic equivalent, due to the amount of land surrounding the northern polar region.

This line, like the Arctic tree line, is a natural boundary rather than an artificial one, like a line of latitude. 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 Georgia and the South Sandwich Islands, Bouvet Island, Heard Island and McDonald Islands all lie south of the Antarctic Convergence.

The Kerguelen Islands lie approximately on the Convergence; the Falkland Islands, Prince Edward Islands, Crozet Islands, Île Amsterdam, Île Saint-Paul, Tierra del Fuego and Macquarie Island lie north of the Convergence.

First crossed by Anthony de la Roché in 1675^[1], and described by Sir Edmund Halley in 1700.^[2]

External links

• Map of Antarctic Convergence

This article incorporates text from Antarctic Convergence, in the Geographic Names Information System, operated by the United States Geological Survey, and therefore a public domain work of the United States Government.

See also

• Antarctic
• Antarctic Circle
• Antarctic Circumpolar Wave
• Antarctic Ocean
• Subantarctic

Notes