Atmospheric Window
Also known as: Sky Window
Atmospheric gases absorb and emit infrared radiation differently at different wavelengths. Within the approximately 8–13 μm atmospheric window, transmission can be relatively high, allowing some surface emission to reach space. Humidity, clouds and wavelength affect this exchange; the window is not perfectly transparent.
Scientific detail
The 8–13 μm atmospheric window sits between the strong CO₂ and H₂O absorption bands. Effective sky brightness temperature within this window can be 40–60 K below ambient under clear conditions, providing the radiative sink that enables sub-ambient PDRC. Cloud cover, high humidity and aerosols increase absorption within the window and diminish net radiative heat loss.
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