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Instrument: radiometer
The GOES Imager is a 5 channels device: visible channel is 0.55-0.75 µm, infrared channels are 3.8-4.0 µm, 10.2-11.2 µm, 11.5-12.5 µm and water vapour channel is 6.5-7.0 µm. In the visible channel, the resolution is 1 km. In the infrared, the resolution is 4 km and in the water vapour channel, the resolution is 8 km.
The radiometer scans the earth's surface line by line; each line consists of a series of individual image elements or pixels. For each pixel the radiometer measures the radiative energy of the different spectral bands. This measurement is digitally coded and transmitted to the ground station for pre-processing before being disseminated to the user community. The data are distributed by the National Environmental Satellite and Information Service (NESDIS)
GOES satellites provide global half-hourly observations. Images of the United States are taken every 15 minutes. It is possible to scan terrestrial areas with more frequent intervals (for example five minutes, even a minute) for the assistance to the NOAA alarm programs.
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