Atmospheric Absorption and Atmospheric Windows

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Figure 2-15. Atmospheric windows with wavelength on the x-axis and percent transmission

measured in hertz on the y-axis. High transmission corresponds to an "atmospheric win-

dow," which allows radiation to penetrate the Earth's atmosphere. The chemical formula is

given for the molecule responsible for sunlight absorption at particular wavelengths across

the spectrum. Modified from

f. Atmospheric Absorption and Atmospheric Windows. Absorption of electromagnetic

radiation is another mechanism at work in the atmosphere. This phenomenon occurs as

molecules absorb radiant energy at various wavelengths (Figure 2-12). Ozone (O3), car-

bon dioxide (CO2), and water vapor (H2O) are the three main atmospheric compounds

that absorb radiation. Each gas absorbs radiation at a particular wavelength. To a lesser

extent, oxygen (O2) and nitrogen dioxide (NO2) also absorb radiation (Figure 2-15). Be-

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