17 January 2009


Albedo: I was looking for words about snow. What's particularly interesting to me about albedo is the feedback aspect. See the Wikipedia quote below.

Al*be"do, n. [L., fr. albus white.]

Whiteness. Specifically: (Astron.) The ratio which the light
reflected from an unpolished surface bears to the total light
falling upon that surface.
[1913 Webster]

-- From The Collaborative International Dictionary of English v.0.48

n : the ratio of reflected to incident light [syn: reflective

-- From WordNet (r) 2.0

"The albedo of an object is the extent to which it diffusely reflects light from the Sun."

Snow albedos can be as high as 90%; this, however, is for the ideal example: fresh deep snow over a featureless landscape. Over Antarctica they average a little more than 80%. If a marginally snow-covered area warms, snow tends to melt, lowering the albedo, and hence leading to more snowmelt (the ice-albedo positive feedback).


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