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Bergeron theory
Bergeron theory (Bergeron—Findeisen theory) A theory, proposed around 1930 by T. Bergeron, and subsequently developed by W. Findeisen, that provides a mechanism for the growth of raindrops in ice/water cloud. It is based on the differential values for saturation vapour pressure over ice and supercooled-water surfaces. At cloud temperatures of −12 to −30°C air can be saturated over ice but not over water particles, so evaporation can take place from the water droplets, and ice particles can grow by sublimation at the expense of water droplets. When they are large enough, the ice particles can fall from the cloud, melting as they pass through lower, warmer air. The process depends on there being a mixture of ice and water, and so may operate in mid- and high-latitude cloud but not in all clouds, e.g. not in tropical clouds which are at temperatures above freezing. See also COLLISION THEORY; and ICE NUCLEUS.
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Cite this article
AILSA ALLABY and MICHAEL ALLABY. "Bergeron theory." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>. AILSA ALLABY and MICHAEL ALLABY. "Bergeron theory." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O13-Bergerontheory.html AILSA ALLABY and MICHAEL ALLABY. "Bergeron theory." A Dictionary of Earth Sciences. 1999. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-Bergerontheory.html |
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Bergeron theory
Bergeron theory(Bergeron–Findeisen theory) A theory proposed around 1930 by T. Bergeron, and subsequently developed by W. Findeisen, that provides a mechanism for the growth of raindrops in ice/water cloud. It is based on the differential values for saturation vapour pressure over ice and supercooled water surfaces. At cloud temperatures of −12 to −30°C air can be saturated over ice but not over water particles, so evaporation can take place from the water droplets, and ice particles can grow by sublimation at the expense of water droplets. When they are large enough the ice particles can fall from the cloud, melting as they pass through lower, warmer air. The process depends on there being a mixture of ice and water, and so may operate in mid- and high-latitude cloud but not in all clouds (e.g. not in tropical clouds which are at temperatures above freezing). See also collision theory and ice nucleus.
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Cite this article
MICHAEL ALLABY. "Bergeron theory." A Dictionary of Ecology. 2004. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>. MICHAEL ALLABY. "Bergeron theory." A Dictionary of Ecology. 2004. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O14-Bergerontheory.html MICHAEL ALLABY. "Bergeron theory." A Dictionary of Ecology. 2004. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O14-Bergerontheory.html |
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