|
Search over 100 encyclopedias and dictionaries: |
Research categories | Follow us on Twitter |
Research categories
View all topics in the newsView all reference sources at Encyclopedia.com |
|||
albedo
albedo The fraction of the total light or other radiation falling on a non-luminous body, such as a planet, or on a planetary surface feature, that is reflected from it. In general, the albedo is equal to the amount of light reflected divided by the amount of light received. Albedo values range from 0.0 (0%) for a totally black surface that absorbs all incident light, to 1.0 (100%) for a perfect reflector. Planets or planetary satellites with dense atmospheres have much higher albedos than those with transparent or no atmospheres. The albedo may vary over the surface, so for practical purposes an average albedo is specified. Natural surfaces reflect different amounts of light in different directions, and albedo can be expressed in several ways according to whether the measurement is made in one direction or averaged over all directions. See Bond Albedo; Geometrical Albedo; Hemispherical Albedo.
|
|
|
Cite this article
"albedo." A Dictionary of Astronomy. 1997. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "albedo." A Dictionary of Astronomy. 1997. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O80-albedo.html "albedo." A Dictionary of Astronomy. 1997. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O80-albedo.html |
|
albedo
albedo The proportion of insolation that is reflected back from the Earth, from the tops of the clouds, and from the atmosphere, without heating the receiving surface. It averages about 30 per cent, but varies widely according to the substance and texture of the surface, and the angle and wavelength of the incident radiation. The value for green grass and forest is 8–27 per cent (over 30 per cent for yellowing deciduous forest in autumn); for cities and rock surfaces 12–18 per cent (over 40 per cent for chalk and light-coloured rock and buildings); for sand up to 40 per cent; for fresh, flat snow up to 90 per cent; and for calm water only 2 per cent in the case of vertically incident radiation but up to 78 per cent where there is a low angle of incidence. The albedo for cloud surfaces averages 55 per cent, but can be up to 80 per cent for thick stratocumulus.
|
|
|
Cite this article
MICHAEL ALLABY. "albedo." A Dictionary of Ecology. 2004. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. MICHAEL ALLABY. "albedo." A Dictionary of Ecology. 2004. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O14-albedo.html MICHAEL ALLABY. "albedo." A Dictionary of Ecology. 2004. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O14-albedo.html |
|
albedo
albedo The proportion of insolation that is reflected back from the Earth, from the tops of the clouds, and from the atmosphere, without heating the receiving surface. It averages about 30%, but varies widely according to the substance and texture of the surface, and the angle and wavelength of the incident radiation. The value for green grass and forest is 8–27% (over 30% for yellowing deciduous forest in autumn); for cities and rock surfaces, 12–18% (over 40% for chalk and light-coloured rock and buildings); for sand up to 40%; for fresh, flat snow up to 90%; and for calm water only 2% in the case of vertically incident radiation but up to 78% where there is a low angle of incidence. The albedo for cloud surfaces averages 55%, but can be up to 80% for thick stratocumulus.
|
|
|
Cite this article
AILSA ALLABY and MICHAEL ALLABY. "albedo." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. AILSA ALLABY and MICHAEL ALLABY. "albedo." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O13-albedo.html AILSA ALLABY and MICHAEL ALLABY. "albedo." A Dictionary of Earth Sciences. 1999. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-albedo.html |
|
albedo
albedo , reflectivity of the surface of a planet, moon, asteroid, or other celestial body that does not shine by its own light. Albedo is measured as the fraction of incident light that the surface reflects back in all directions. A perfect reflector by definition has an albedo of unity, i.e., all the incident light is reflected; a body that reflects no light at all would have an albedo of zero. Real surfaces have albedos between these values. The albedos of planets, moons, and asteroids provide valuable information about the structure and composition of their surfaces. The dark regions on the earth's moon give it the very low average albedo of 0.07, while highly reflective clouds give Venus an albedo of 0.85, the highest of any body in the solar system. |
|
|
Cite this article
"albedo." The Columbia Encyclopedia, 6th ed.. 2008. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "albedo." The Columbia Encyclopedia, 6th ed.. 2008. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1E1-albedo.html "albedo." The Columbia Encyclopedia, 6th ed.. 2008. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-albedo.html |
|
albedo
al·be·do / alˈbēdō/ • n. (pl. -dos) chiefly Astron. the proportion of the incident light or radiation that is reflected by a surface, typically that of a planet or moon. |
|
|
Cite this article
"albedo." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "albedo." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O999-albedo.html "albedo." The Oxford Pocket Dictionary of Current English. 2009. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O999-albedo.html |
|
albedo
|
|
|
Cite this article
DAVID A. BENDER. "albedo." A Dictionary of Food and Nutrition. 2005. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. DAVID A. BENDER. "albedo." A Dictionary of Food and Nutrition. 2005. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O39-albedo.html DAVID A. BENDER. "albedo." A Dictionary of Food and Nutrition. 2005. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O39-albedo.html |
|
albedo
albedo Fraction of light or other radiation that is reflected from a surface. An ideal reflector has an albedo of 1; those of real reflectors are less; that of the Earth, viewed from satellites, is 0.35.
|
|
|
Cite this article
"albedo." World Encyclopedia. 2005. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "albedo." World Encyclopedia. 2005. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O142-albedo.html "albedo." World Encyclopedia. 2005. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O142-albedo.html |
|
|
Search over 100 encyclopedias and dictionaries:
HighBeam™ Research, Inc. © Copyright 2012. All rights reserved.
The Encyclopedia.com advertising network includes:
