<P> Albedo (/ ælˈbiːdoʊ /) (Latin: albedo, meaning "whiteness") is the measure of the diffuse reflection of solar radiation out of the total solar radiation received by an astronomical body (e.g. a planet like Earth). It is dimensionless and measured on a scale from 0 (corresponding to a black body that absorbs all incident radiation) to 1 (corresponding to a body that reflects all incident radiation). </P> <P> Surface albedo is defined as the ratio of irradiance reflected to the irradiance received by a surface . The proportion reflected is not only determined by properties of the surface itself, but also by the spectral and angular distribution of solar radiation reaching the Earth's surface . These factors vary with atmospheric composition, geographic location and time (see position of the Sun). While bi-hemispherical reflectance is calculated for a single angle of incidence (i.e., for a given position of the Sun), albedo is the directional integration of reflectance over all solar angles in a given period . The temporal resolution may range from seconds (as obtained from flux measurements) to daily, monthly, or annual averages . </P>

More solar energy is reflected back to space (30 ) than is absorbed directly by the atmosphere (20 )