Reference Entry


Michael Allaby

in A Dictionary of Geology and Earth Sciences

Fourth edition

Published in print January 2013 | ISBN: 9780199653065
Published online September 2013 | e-ISBN: 9780191744334

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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 ...

Reference Entry.  139 words. 

Subjects: Earth Sciences and Geography

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