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Scanning Microwave Spectrometer (SCAMS)

NSSDC ID: 1975-052A-10
Mission Name: Nimbus 6
Principal Investigator: Prof. David H. Staelin


The Nimbus 6 Scanning Microwave Spectrometer (SCAMS) was designed to map tropospheric temperature profiles, water vapor abundance, and cloud water content to be used for weather prediction even in the presence of clouds, which block conventional satellite infrared sensors. The instrument was an advancement of the Nimbus E microwave spectrometer (NEMS) on Nimbus 5. The SCAMS continuously monitored emitted microwave radiation at frequencies of 22.235, 31.65, 52.85, 53.85 and 55.45 GHz. The three channels near the 5.0-mm oxygen absorption band were used primarily to deduce atmospheric temperature profiles. The two channels near 10 mm permitted water vapor and cloud water content over calm oceans to be estimated separately. The instrument, a Dicke-superheterodyne type, scanned plus or minus 45 deg normal to the orbital plane with a 10-deg field of view. The three oxygen channels shared common signal and reference antennas. Both water vapor channels had their own signals and reference antennas. The absolute rms accuracy of the oxygen channels was better than 2 deg K and that of the water vapor channels better than 1 deg K. The dynamic range for all channels was 0-400 deg K. The ground resolution was approximately 145 km near nadir and 330 km at the scan limit. For a more detailed description, see Section 4 in "The Nimbus 6 User's Guide" (TRF B23261), available from NSSDC. The instrument ceased functioning on May 31, 1976, due to jamming of the scan mechanism. Selected SCAMS images were presented in "The Nimbus 6 Data Catalog" (TRF B26731), also available from NSSDC.

Alternate Names


Facts in Brief

Mass: 23.4 kg
Power (avg): 46.0 W
Bit rate (avg): 0.12 bps

Funding Agency

  • Unknown (United States)


  • Earth Science: Atmospheric Dynamics

Additional Information

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



NameRoleOriginal AffiliationE-mail
Prof. Alan H. BarrettOther InvestigatorMassachusetts Institute of Technology 
Prof. David H. StaelinPrincipal InvestigatorMassachusetts Institute of
Mr. W. Scott PhillipsOther InvestigatorMassachusetts Institute of
Mr. Frank T. BarathOther InvestigatorNASA Jet Propulsion
Dr. William B. LenoirOther InvestigatorNASA Johnson Space Center 
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