Developed by CNES in partnership with Eumetsat, the IASI instrument (Infrared Atmospheric Sounding Interferometer) is flying on the European MetOp series of weather satellites. Besides acquiring temperature and humidity data, IASI also measures more than 25 other atmospheric components with high precision and is supporting the efforts of scientists monitoring Earth’s climate.

The IASI interferometer measures atmospheric temperature and humidity with extreme precision, as well as detecting trace gases like ozone, methane and carbon monoxide, and monitoring a range of other variables—clouds, aerosols and greenhouse gases—vital to climate research. IASI instruments are currently flying on the European MetOp-A and MetOp-B weather satellites, launched in 2006 and 2012 by the European Space Agency (ESA) and Eumetsat (EUropean organisation for the exploitation of METeorological SATellites). IASI will also fly on MetOp-C, scheduled to join its sister satellites in orbit in 2018. After that, the programme will be continued with the IASI-NG new-generation instrument, now in phase B at CNES, which will fly on the MetOp-SG weather satellites.

Built by Thales Alenia Space with technical oversight from CNES, IASI comprises two main elements: a spectrometer designed to resolve atmospheric infrared radiation into line spectra, and an imager to locate points to be sounded. The instrument also features in-built data processing software developed by CNES. A technical expertise centre at CNES’s Toulouse Space Centre is tasked with monitoring the IASI system’s performance and handling any anomalies. Data are processed on the ground by Eumetsat. France is playing a pre-eminent role in the broad scientific community exploiting data from the IASI mission.