A Closer Look at Albedo
The DaisyWorld example illustrates albedo, which is the percentage of the Sun’s energy that is reflected off a surface. Albedo values range from 0 to 1 (or 0–100 percent). A pure black surface absorbs all of the incoming light and reflects none (0 percent), so it has an albedo value of 0. A mirror, on the other hand, which absorbs no light and reflects all of it (100 percent), has an albedo value of 1. In general, the higher the albedo of a surface, the more light it reflects; the lower the albedo, the more light it absorbs. The images below show the typical albedo values of some common materials.
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Notice that albedo can vary even in the same material, depending on its composition, the angle at which sunlight strikes its surface, or even how wet it is! For example, soil is darker when it gets wet from rain, so it absorbs more sunlight, decreasing its albedo. When the Sun shines directly over the ocean, water can absorb much of the light, so the albedo is low. But when the Sun is setting and near the horizon, the sunlight can bounce off the surface of the ocean, making the ocean's albedo much higher.
Overall, Earth has an average albedo of 0.3, mostly due to the effects of clouds; it reflects back 30 percent of the light it receives.
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