What is the 8-14 micrometre infrared band of high atmospheric transmission called?

The 8–14 micrometre infrared band of relatively high atmospheric transmission is called the atmospheric window.

Earth’s atmosphere absorbs thermal infrared radiation unevenly. Between roughly 8 and 14 micrometres, absorption is comparatively weak, allowing some radiation emitted by the surface and lower atmosphere to escape directly to space. This “window” is central to Earth’s energy balance and is one reason the greenhouse effect depends strongly on the detailed spectrum of atmospheric gases.

The gap is mainly associated with relatively weak water-vapour absorption in that region. Carbon dioxide helps define the long-wavelength boundary, while ozone absorbs part of the middle of the band. Clouds and humid air can narrow or close the window, so it is not an always-open hole in the atmosphere.

George Simpson highlighted the atmospheric window’s importance for planetary heat balance in 1928. A common mistake is to treat the quoted 8–14 micrometre range as a rigid universal boundary: the exact transmission varies with humidity, clouds, altitude, and the observing path.