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polar front

 
Dictionary: polar front

n.
The region or boundary separating air masses of polar origin from those of tropical or subtropical origin.


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Geography Dictionary: polar front
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The discontinuous, variable front which forms over the north Atlantic and north Pacific, where polar maritime air meets tropical maritime air. The formation of mid-latitude depressions at the polar front is connected with the development of troughs in the polar front jet stream, a band of high-velocity winds in the wider Rossby waves. The polar front jet stream, and hence the polar front, moves southwards in winter and northwards in summer. Polar easterlies blow east-west, from polar highs to sub-polar lows.

 
Columbia Encyclopedia: polar front
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polar front, zone of transition between polar and tropical air masses. Its average position during the winter is at about 30° lat. and during the summer at about 60° lat. In the N Atlantic Ocean, for example, the polar front can often be traced as a continuous line extending over thousands of miles, usually toward the northeast from a point just off the coast of the United States at about 30°N. Most cyclones outside the tropics develop along the polar front from waves caused by the juxtaposition of cold air moving toward the equator and hot air moving toward the poles; the earth's rotation gives this air its cyclonic twist. See front.


WordNet: polar front
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Note: click on a word meaning below to see its connections and related words.

The noun has one meaning:

Meaning #1: the front of an advancing mass of colder air
  Synonym: cold front


Wikipedia: Polar front
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AtmosphCirc2.png

In meteorology, the polar front is the boundary between the polar cell and the Ferrel cell in each hemisphere. At this boundary a sharp gradient in temperature occurs between these two air masses, each at very different temperatures.

The polar front arises as a result of cold polar air meeting warm tropical air. It is a stationary front as the air masses are not moving against each other. Off the coast of eastern North America, especially in winter, there is a sharp temperature gradient between the snow-covered land and the warm offshore currents.

The polar front theory says that mid-latitude cyclones form on boundaries between warm and cold air. In winter, the polar front shift towards the Equator, whereas high pressure systems can dominate more in the summer.

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Copyrights:

Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.  Read more
Geography Dictionary. A Dictionary of Geography. Copyright © Susan Mayhew 1992, 1997, 2004. All rights reserved.  Read more
Columbia Encyclopedia. The Columbia Electronic Encyclopedia, Sixth Edition Copyright © 2003, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/ Read more
WordNet. WordNet 1.7.1 Copyright © 2001 by Princeton University. All rights reserved.  Read more
Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "Polar front" Read more