The AVHRR five channel scanning radiometer with 1.1-km resolution is sensitive in the visible and near-infrared, and the infrared 'window' regions. This instrument will be carried through NOAA-J (14); NOAA-K, L and M (15, 16, and 17) and will have a similar instrument with six channels and other improvements. AVHRR data are broadcast for reception by ground stations and also tape-recorded onboard the spacecraft for readout at the Fairbanks and Wallops Command Data Acquisition stations. These data can be recorded in 1.1-km resolution (the basic resolution of the AVHRR instrument) or at 4 km resolution; the swath width is >2600 km. The stored high resolution (1.1-km) imagery is known as Local Area Coverage (LAC). Owing to the large number of data bits, only about 11+ minutes of LAC can be accommodated on a single recorder. In contrast, 115 minutes of the lower resolution (4-km) imagery, called Global Area Coverage (GAC), can be stored on a recorder, enough to cover an entire 102 minute orbit of data.

The AVHRR has flown on the following U.S. civilian meteorological satellites: TIROS-N; NOAA-6 through NOAA-14, inclusive.

NOAA-K, L and M (NOAA-15 onwards) carry an enhanced version of the AVHRR scanner. It has six channels (three visible and three infra-red) but, for compatibility at receiving stations, only five are transmitted. Channel 3 is the visible channel during the daytime and the infra-red channel at nighttime, although sometimes it is infra-red during the day too for fire detection. Additionally, the visible channels have been modified with a dual slope for calibration to give greater sensitivity at low light levels.

Channel Wavelength
(microns)
Primary Use
1 0.58 - 0.68 Daytime cloud/surface mapping
2 0.725 - 1.10 Surface water delineation, ice and snow melt
3A 1.58 - 1.64 Snow / ice discrimination (NOAA K,L,M)
3 (or 3B) 3.55 - 3.93 Sea surface temperature, nighttime cloud mapping
4 10.30 - 11.30 Sea surface temperature, day and night cloud mapping
5 11.50 - 12.50 Sea surface temperature, day and night cloud mapping

Entry taken from:
Rao,P.K., S.J. Holmes, R.K. Anderson, J.S. Winston, P.E. Lehr, Weather Satellites: Systems, Data, and Environmental Applications, American Meteorological Society, Boston, 1990. ISBN 0-933876-66-1


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