The Climate Machine: Atmospheric Band Absorption

The atmosphere attenuates both longwave and shortwave radiation and reduces the amount of sunlight that reaches the surface and the amount of longwave radiation that leaves the top of atmosphere.  Below is a graph showing the longwave radiation emitted a blackbody surface of a given temperature and the amount emitted to space. For shortwave spectral absorption, click here.
The graph on the right shows the amount of longwave radiation that is emitted to space. An important atmospheric window exists from 8 to 13 micrometers. 

Energy emitted through this window accounts for almost half of longwave radiation emitted to space. CO2 and H2O absorbs radiation at wavelengths longer than the atmospheric window while ozone and methane absorb at wavelengths shorter than the window. 

Within the window, some absorption occurs as well (due to CO2 and ozone) but the total absorption is weak in most regions of the globe.

Other important absorbers include CH4, N2O and CFC's.

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