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TIROS Operational Vertical Sounder

NSSDCA ID: 1981-059A-02

Mission Name: NOAA 7
Principal Investigator:


The TIROS Operational Vertical Sounder (TOVS) consisted of three instruments: the high-resolution infrared radiation sounder modification 2 (HIRS/2), the stratospheric sounding unit (SSU), and the microwave sounding unit (MSU). All three instruments were designed to determine radiances needed to calculate temperature and humidity profiles of the atmosphere from the surface to the stratosphere (approximately 1 mb). The HIRS/2 instrument had 20 channels in the following spectral intervals: channels 1 through 5 , the 15-micrometer CO2 bands (15.0, 14.7, 14.5, 14.2, and 14.0 micrometers); channels 6 and 7, the 13.7- and 13.4-micrometer CO2/H2O bands; channel 8, the 11.1-micrometer window region; channel 9, the 9.7-micrometer ozone band; channels 10, 11, and 12, the 6-micrometer water vapor bands (8.3, 7.3, and 6.7 micrometers); channels 13 and 14, the 4.57- and 4.52-micrometer N2O bands; channels 15 and 16, the 4.46- and 4.40-micrometer CO2/N2O bands; channel 17, the 4.24-micrometer CO2 band; channels 18 and 19, the 4.0- and 3.7-micrometer window bands; and channel 20, the 0.70-micrometer visible region. The SSU instrument was provided by the British Meteorological Office. It was similar to the pressure-modulated radiometer (PMR) flown on Nimbus 6. The SSU operated at three 15.0-micrometer channels using selective absorption, passing the incoming radiation through three pressure-modulated cells containing CO2. The MSU instrument was similar to the scanning microwave spectrometer (SCAMS) flown on Nimbus 6. The MSU had one channel in the 50.31-GHz window region and three channels in the 55-GHz oxygen band (53.73, 54.96, and 57.95 GHz) to obtain temperature profiles which were free of cloud interference. The HIRS/2 had a field of view (FOV) 30 km in diameter at nadir, whereas the MSU had a FOV of 110 km in diameter. The HIRS/2 sampled 56 FOVs in each scan line about 2250 km wide, and the MSU sampled 11 FOVs along the swath with the same width. Each SSU scan line had 8 FOVs with a width of 1500 km. This experiment was also flown on other TIROS-N/NOAA series spacecraft. For a more detailed description, see W. L. Smith, "The TIROS-N operational vertical sounder," Bull. Am. Meteorol. Soc., v. 60, pp. 1177-1187, 1979. Archival data are available from the Satellite Data Services Division, National Climatic Center, NOAA, Washington, D.C.

Alternate Names

  • TOVS

Facts in Brief

Mass: 63.4 kg
Power (avg): 75 W

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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