Advanced very-high-resolution radiometer

Advanced very-high-resolution radiometer (AVHRR) instruments are a type of space-borne sensor that measure the reflectance of the Earth in five spectral bands that are relatively wide by today's standards. Most AVHRR instruments are or have been carried by the National Oceanic and Atmospheric Administration (NOAA) family of polar orbiting platforms (POES). The first two are centered on the red (0.6 micrometres, 500 THz) and near-infrared (0.9 micrometres, 300 THz) regions, the third one is located around 3.5 micrometres, and the last two sample the thermal radiation emitted by the planet, around 11 and 12 micrometres, respectively. The NOAA satellite has equator crossing times of 0730 and 1930 local solar time.