Measurement of sea surface temperature from HIRS2/MSU

The High-Resolution Infrared Sounder (HIRS), a 20-channel infrared sounder, and the Microwave Sounding Unit (MSU), a 4-channel microwave sounder, were first launched on the TIROS-N Satellite in November 1978 as an upgraded operational temperature sounding system. Essentially identical instruments have flown on NOAA-6 and NOAA-7 and are scheduled to fly on future operational satellites through the eighties. While HIRS2 and MSU were designed primarily for the purpose of measuring atmospheric temperature profiles, the observed radiances are also sensitive to other meteorological parameters such as sea surface temperature, ground temperature, cloud height and cloud amount, ice extent over ocean, snow cover over land, etc. A physically based processing system for analysis of HIRS2/MSU data was developed to determine the above atmospheric and surface parameters, which when substituted in the radiative transfer equation, match the satellite observations to a given noise level. All parameters are retrieved in a mutually interacting fashion.