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Scanning Radiometer (SR)

NSSDCA ID: 1973-086A-02

Mission Name: NOAA 3
Principal Investigator:


The NOAA 3 (ITOS-F) Scanning Radiometer (SR) subsystem consisted of two scanning radiometers, a dual SR processor and two SR recorders. This subsystem permitted the determination of surface temperatures of the ground, the sea, or cloud tops viewed by the radiometer. The radiometer measured reflected radiation from the earth/atmosphere system in the 0.52- to 0.73-micron band during the day and emitted radiation from the earth and its atmosphere in the 10.5- to 12.5-micron band during the day and night. Unlike a camera, the SR did not take a picture but instead formed an image using a continuously rotating mirror. The mirror scanned the earth's surface perpendicular to the satellite's orbital path at a rate of 48 rpm. As the satellite progressed along its orbital path, each rotation of the mirror provided one scan line of picture. Radiation collected by the mirror passed through a beam splitter and spectral filter to produce the desired spectral separation. Up to two full orbits of data (145 min) were stored on magnetic tape for subsequent transmission (1697.5 MHz) to an acquisition station. The data were also transmitted in real time to local APT stations. Once the signal was received by the ground station, a continuous picture was formed by using a facsimile recorder whose scan was in phase with the satellite's forward motion. From a planned altitude of 1460 km, the radiometer had a ground resolution of approximately 4 km at nadir and was capable of yielding radiance temperatures between 185 and 330 deg k to an accuracy of +4 and -1 deg k, respectively. All operational data from this experiment were handled by NOAA and will eventually be archived at the National Climatic Center, Asheville, NC. Identical experiments were flown on NOAA 1, NOAA 2, and NOAA 4.

Alternate Names

  • NOAA3/SR
  • SR

Funding Agency

  • NOAA National Environmental Satellite Service (United States)


  • Earth Science: Atmospheric Dynamics

Additional Information

Questions and comments about this experiment can be directed to: Coordinated Request and User Support Office



NameRoleOriginal AffiliationE-mail
Principal InvestigatorNOAA National Environmental Satellite, Data and Information Service
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