A 20-channel infrared radiometric sounder carried by NOAA polar-orbiting meteorological satellites. Data, when combined with observations from the Advanced Microwave Sounding Units, are used to determine atmospheric temperature and pressure profiles to altitudes of c.40 km. HIRS data also measure sea-surface temperatures, ozone levels, precipitable water, and cloud properties (height, coverage, and albedo). Legacy units are being fitted to Eumetsat MetOp satellites (see Initial Joint Polar System.)
Subjects: Meteorology and Climatology.