Satellite infrared spectrometer

From Glossary of Meteorology

Satellite Infrared Spectrometer

(Abbreviated SIRS.) The first space-based, grating spectrometer used for vertical temperature soundings of the atmosphere.

SIRS was flown on ''Nimbus''-3 and -4 launched in April 1969 and April 1970, and was a forerunner of the ''HIRS''-2 operational instrument on the TIROS-N satellites since 1978.