For an accurate and reliable weather forecasting and enhanced understanding of atmospheric chemistry

To improve the quality of forecasts out to a few days, weather services need more detailed data concerning atmospheric humidity and temperature profiles. The IASI optical instrument is designed to achieve just that.

IASI provides weather forecasters with atmospheric infrared emission spectra of unprecedented accuracy, twice daily. It makes it possible to establish temperature and humidity profiles with a vertical resolution of 1 km, accurate to 1°C and 10% respectively.

The instrument comprises a spectrometer that resolves infrared radiation into line spectra and detects minority species like ozon, carbon monoxide, methane and also ammonia that interests the atmospheric chemistry domain. It also has an imager operating in tandem with the spectrometer to locate soundings.

Operating alongside the other instruments on the Metop satellites, with a planned service life of 15 years, it is a key link in the chain of systems monitoring the environment and global climate. IASI programme is composed of 3 instruments on-board 3 successive Metop satellites.

IASI is a joint CNES/Eumetsat initiative.

CNES has overall technical responsibility for the instruments and development of the data-processing software. It also set up a technical expertise centre. Since the end of in-orbit checkout of the 1^st instrument, CNES has acted as the design authority for the flight and ground instruments, is maintaining the level-1 processing system and running the technical expertise centre. Eumetsat will operate the IASI instrument and process, archive and distribute data to users.

IASI is the core payload of Europe’s series of 3 MetOp satellites, the 1^st of which was launched into sun-synchronous orbit on 19 October 2006.

_{Updated : July 2010}