The term is applied in particular to devices used to measure infrared radiation.
2. A receiver for detecting microwave thermal radiation and similar weak wide-band signals that resemble noise and are obscured by receiver noise.The primary application of an atmospheric radiometer has been on board spacecraft measuring atmospheric and terrestrial radiation, and they are mostly used for meteorological or oceanographic remote-sensing.
Their secondary application is also meteorological, as zenith-pointing surface instruments that view the earth's atmosphere in a region above the stationary instrument.
By understanding the physical processes associated with energy emission at these wavelengths, scientists can calculate a variety of surface and atmospheric parameters from these measurements, including air temperature, sea surface temperature, salinity, soil moisture, sea ice, precipitation, the total amount of water vapor and the total amount of liquid water in the atmospheric column directly above or below the instrument.