This article has been reviewed by the following Topic Editor: C Michael Hogan
The Antarctic Convergence, also known as the Polar Front, is a line encircling Antarctica where the cold, northward-flowing Antarctic waters sink beneath the relatively warmer waters of the sub-Antarctic.
Antarctic Convergence . Source: Michigan State University
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. It reaches south of 60 degrees south near New Zealand and near 48 degrees south in the far South Atlantic coinciding with the path of the maximum velocity westerly winds.
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 to 5.5 Celsius).
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.
The hydrologic trasition that occurs at the convergence is shown in the diagram below. The easterly flowing Antarctic Circumpolar Current (ACC) moves the Antarctic Surface Water at the surface south of the Convergence. At the Convergence and north of it, the Antarctic Surface Water sinks to become Antarctic Intermediate Water under warmer Subantarctic Surface Water.
Schematic diagram of sea currents and depth zones in the Antarctic region.
The Antarctic Convergence not only separates two hydrological regions, but also separates areas of distinctive marine life associations and of different climates. The term Polar Front is used because it marks the transition between the Polar Frontal Zone (PFZ) to the north and the Antarctic Zone (AZ) to the south.
The Antarctic Convergence marked against an image of ice cover on the Southern Ocean during the southern winter. NASA/National Snow and Ice Data Center
Further Reading
Physical Oceanography Index
Below the Convergence: Voyages Towards Antarctica, 1699-1839, Alan Gurney, W.W. Norton and Company, 1997 ISBN: 0393039498.
Matthias Tomczak and J. Stuart Godfrey. Regional Oceanography: An Introduction. Pergamon, 1994, pp. 76-79.
U.S. Geological Survey (Lead Author);Steve Baum, Peter Saundry (Contributing Author);C Michael Hogan (Topic Editor) "Antarctic Convergence". In: Encyclopedia of Earth. Eds. Cutler J. Cleveland (Washington, D.C.: Environmental Information Coalition, National Council for Science and the Environment). [First published in the Encyclopedia of Earth March 30, 2010; Last revised Date June 1, 2011; Retrieved May 22, 2012 <http://www.eoearth.org/article/Antarctic_Convergence>
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The Antarctic Convergence, also known as the Polar Front, is a line encircling Antarctica where the cold, northward-flowing Antarctic waters sink beneath the relatively warmer waters of the sub-Antarctic.
Antarctic Convergence . Source: Michigan State University
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. It reaches south of 60 degrees south near New Zealand and near 48 degrees south in the far South Atlantic coinciding with the path of the maximum velocity westerly winds.
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 to 5.5 Celsius).
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.
The hydrologic trasition that occurs at the convergence is shown in the diagram below. The easterly flowing Antarctic Circumpolar Current (ACC) moves the Antarctic Surface Water at the surface south of the Convergence. At the Convergence and north of it, the Antarctic Surface Water sinks to become Antarctic Intermediate Water under warmer Subantarctic Surface Water.
Schematic diagram of sea currents and depth zones in the Antarctic region.
The Antarctic Convergence not only separates two hydrological regions, but also separates areas of distinctive marine life associations and of different climates. The term Polar Front is used because it marks the transition between the Polar Frontal Zone (PFZ) to the north and the Antarctic Zone (AZ) to the south.
The Antarctic Convergence marked against an image of ice cover on the Southern Ocean during the southern winter. NASA/National Snow and Ice Data Center
Further Reading
Physical Oceanography Index
Below the Convergence: Voyages Towards Antarctica, 1699-1839, Alan Gurney, W.W. Norton and Company, 1997 ISBN: 0393039498.
Matthias Tomczak and J. Stuart Godfrey. Regional Oceanography: An Introduction. Pergamon, 1994, pp. 76-79.
Antarctic Convergence . Source: Michigan State University
Schematic diagram of sea currents and depth zones in the Antarctic region.
The Antarctic Convergence marked against an image of ice cover on the Southern Ocean during the southern winter. NASA/National Snow and Ice Data Center
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