Can anyone tell me what is the difference between Albedo and surface reflectance? I know for sure that they are not the same. Any links / comments are most welcome.
Albedo is the percentage of solar energy striking a surface that is reflected away from the earth.
Surface Reflectance is ratio of the amount light not absorbed by a surface to the amount of light striking the surface.
Albedo is a measure of energy and Surface Reflectance is a property of a material.
Solar radiation times the percentage that gets through the atmosphere and strikes the surface times the Surface Reflectance ratio equals Albedo.
A perfect mirror at night produces zero Albedo.
I agree with @blah238 here is more information Albedo is the percentage of solar radiation reflected by an object. Reflectivity is the capacity of an object to reflect solar radiation. It is described as a function of radiation wavelength and is determined by the physical composition of the object.
Relation of reflectivity to albedo Albedo is the integrated product of incident solar radiation spectral composition and the spectral reflectivity of the object. Outside the atmosphere, solar radiation spectral composition is relatively constant, peaking at about 0.5µm, decreasing rapidly at shorter wavelengths to small amounts at 0.2µm, and decreasing less rapidly at longer wavelengths to small amounts at about 4.0µm. The atmosphere selectively absorbs and scatters solar radiation. As a result, at the Earth’s surface the spectral composition of solar radiation varies significantly as a function of atmospheric conditions (e.g. clouds, water vapor, and dust) and solar elevation (Robinson, 1966; Dickinson, 1983). The majority of albedo measurements have been carried out under clear-sky, high-sun elevation conditions (Table A15). Under cloudy conditions radiation is predominantly in the visible spectrum. This decreases the albedos of soils and vegetation but increases snow albedo (Miller, 1981). When atmospheric turbidity is high, or the sun is low in the sky, the spectral distribution of solar radiation shifts to the red and infrared portion of the spectrum. Soil and vegetation albedos increase and snow albedo decreases (Kondrotyev, 1973). This variability points out the need to know both the spectral reflectivity of objects and the spectral composition of incident radiation in order to evaluate earth albedos.