期刊名称：Geological Survey of Denmark and Greenland Bulletin
印刷版ISSN：1604-8156
出版年度：2017
卷号：38
页码：53-56
语种：English
出版社：De Nationale Geologiske Undersoegelser for Danmark og Groenland
摘要：Albedo, Latin for 'whiteness', is a term used to describe the amount of sunlight reflected by the ground. Fresh snow albedo can exceed 85%, making it among the most reflective natural substances. Warm conditions promote snow crystal metamorphosis that, like the presence of liquid water, bring snow albedo down below 65%. With the darkening, caused by the metamorphosis, absorbed solar energy thus increases by roughly a factor of two. Seasonal snow melts over the lower reaches of a glacier leading to the exposure of bare ice with albedo below 55%. Impurities such as dust, black carbon or microbes can bring glacier-ice albedo below 30%, meaning that snow ablation gives way to impurity-rich, bare glacier ice which increases absorbed sunlight by more than a factor of three.
