View source for Antarctic Convergence

{{Short description|Separation of two hydrological & climatic regions}}

[[File:Antarctic-Convergence-Map.TIF|thumb|200px|right|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 [[subantarctic|sub-Antarctic]].  The line separates the [[clockwise]] [[Antarctic circumpolar current]] from other oceans. <ref name="Pyne">{{cite book |last=Pyne |first=Stephen J |title=The Ice: A Journey to Antarctica |location=New York |publisher=Ballantine Books |year=1986 |isbn=0-345-34845-1|page=34}}</ref>  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 [[Tree line#Arctic|Arctic tree line]], is a natural boundary rather than an artificial one, such as the [[border]]s of [[nation]]s and [[time zone]]s. It not only separates two [[hydrology|hydrological regions]], but also separates areas of distinctive [[marine life]] and [[climate]]s.

The [[Arctic]] has no similar boundary because of the large bodies of land [[Geographic contiguity|contiguous]] with the northern polar region.

==History==
The Antarctic Convergence was first crossed by [[Anthony de la Roché]] in 1675<ref>R.K. Headland, ''The Island of South Georgia'', Cambridge University Press, 1984.{{ISBN?}}{{page?|date=September 2021}}</ref> and [[Edmond Halley]] in 1700,<ref>Alan Gurney, ''Below the Convergence: Voyages Toward Antarctica, 1699–1839'', Penguin Books, New York, 1998.{{ISBN?}}{{page?|date=September 2021}}</ref> and first described by the British [[Discovery Investigations]] and the German [[German Meteor expedition|Meteor Expedition]] in 1925–1927.<ref name=Chronology>Headland, Robert Keith. (2009). ''A Chronology of Antarctic Exploration''. London: Bernard Quaritch. 716&nbsp;pp. / [https://web.archive.org/web/20230320085732/https://southgeorgiaassociation.org/south-georgia-chronology-2/ Extract]</ref>

==Location==
The Antarctic Convergence is a zone approximately {{convert|32|to|48|km|mi|abbr=on}} wide, varying in latitude seasonally and in different [[longitude]]s, extending across the [[Atlantic Ocean|Atlantic]], [[Pacific Ocean|Pacific]], and [[Indian Ocean|Indian]] [[ocean]]s between the [[48th parallel south|48th]] and [[61st parallel south|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°."<ref>Convention on the Conservation of Antarctic Marine Living Resources 1980, Article 1(4).</ref> 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, {{convert|2.8|C-change|abbr=on}} from {{convert|5.6|°C|°F|abbr=on}} to below {{convert|2|°C|°F|abbr=on}}.

===Subantarctic islands lying north of the Convergence===
* {{Flagdeco|French Southern Territories}} [[Île Amsterdam|Amsterdam Island]] ([[France]])
* {{Flagdeco|French Southern Territories}} [[Crozet Islands]] ([[France]])
* {{Flagdeco|Chile}} [[Diego Ramírez Islands]] ([[Chile]])
* {{Flag|Falkland Islands}} ([[Argentina]])
* {{Flagdeco|Argentina}} [[Isla de los Estados]] ([[Argentina]])
* {{Flagdeco|Tasmania}} [[Macquarie Island]] ([[Australia]])
* {{Flagdeco|New Zealand}} [[New Zealand Subantarctic Islands|NZ Subantarctic Islands]] ([[New Zealand]])
** [[Antipodes Islands]]
** [[Auckland Islands]]
** [[Bounty Islands]]
** [[Campbell Islands]]
** [[Snares Islands / Tini Heke|Snares Islands]]
* {{Flagdeco|New Zealand}} [[Chatham Islands]] ([[New Zealand]])
* {{Flagdeco|South Africa}} [[Prince Edward Islands]] ([[South Africa]])
* {{Flagdeco|French Southern Territories}} [[Île Saint-Paul|Saint Paul Island]] ([[France]])
* {{Flagdeco|Argentina}} / {{Flagdeco|Chile}} [[Tierra del Fuego]] ([[Argentina]] / [[Chile]])
* {{Flag|Tristan da Cunha}} ([[The Crown|United Kingdom]])
** {{Flagdeco|Tristan da Cunha}} [[Gough Island]]

=== Islands which lie to the south of the Convergence ===
==== North of 60°S latitude ====

* {{Flag|Bouvet Island}} ([[Norway]])
* {{Flag|Heard Island and McDonald Islands}} ([[Australia]])
* {{Flagdeco|French Southern Territories}} [[Kerguelen Islands]] ([[France]])
* {{Flag|South Georgia and the South Sandwich Islands}} ([[Argentina]])

==== South of 60°S latitude ====

* {{Flagdeco|Antarctica}} [[Balleny Islands]] (''[[Antarctic Treaty System]]'')
* {{Flagdeco|Antarctica}} [[Peter I Island]] (''[[Antarctic Treaty System]]'')
* {{Flagdeco|Antarctica}} [[Scott Island]] (''[[Antarctic Treaty System]]'')
* {{Flagdeco|Antarctica}} [[South Orkney Islands]] (''[[Antarctic Treaty System]]'')
* {{Flagdeco|Antarctica}} [[South Shetland Islands]] (''[[Antarctic Treaty System]]'')

==See also==
{{Portal|Geography}}
* [[Anthony de la Roché]]
* [[Antarctic]]
* [[Antarctic Circle]]
* [[Antarctic Circumpolar Wave]]
* [[Polar front]]
* [[Southern Ocean]]

==References==
{{reflist}}
* {{usgs-gazetteer|id=488}}

==External links==
* [https://www.grida.no/resources/5505 Map of Antarctic Convergence]

{{Antarctica}}
{{Regions of the world}}

[[Category:Currents of the Southern Ocean]]