Albedo is the ratio of the amount of radiation reflected from an object's surface compared to the amount that strikes it. So the Albedo is a measure for the ability of reflection of a corpus. Reflection means both, the direct and the diffuse reflection. Albedo is not a constant parameter. It depends for example on the altitude of the sun. The highest values are reached when the sun is positoned near horizon. It also depends on the properties of the surface, e.g. the polar caps have a very high, the oceans a low albedo.