SEVIRI

SEVIRI
Name	SEVIRI
Operator	European Space Agency / EUMETSAT
Spacecraft	Meteosat Second Generation
Mission type	Meteorological
Launch	Ariane 5
Orbit	Geostationary orbit
Instrument type	Radiometer
Wavelength	Visible, near-infrared, infrared
Mass	55 kg (instrument)
Power	120 W (instrument)
Dimensions	1.0 m × 0.6 m × 0.6 m

SEVIRI is a spaceborne imaging radiometer flown on the Meteosat Second Generation series of geostationary meteorological satellites operated by EUMETSAT and launched on Ariane 5 vehicles. Designed for high temporal and spatial monitoring, the instrument supports operational services including weather forecasting, climate monitoring, and severe-event detection for regions centered on Europe, Africa, and the Atlantic Ocean. SEVIRI provides multispectral data that feeds into numerical weather prediction systems run by agencies such as ECMWF, UK Met Office, and Météo-France.

Overview

SEVIRI is a spin-stabilised, scanning multispectral imager installed on the Meteosat Second Generation platform developed by EUMETSAT in partnership with the European Space Agency. It was conceived to succeed instruments aboard the Meteosat First Generation and to complement polar-orbiting sensors flown on NOAA and Metop spacecraft. SEVIRI’s combination of frequent full-disk imaging and targeted rapid-scan modes supports operational services provided by organizations including National Oceanic and Atmospheric Administration, Deutscher Wetterdienst, Serviço Nacional de Meteorologia e Geofísica, and research groups at ECMWF and CIRA.

Instrument Design and Specifications

The SEVIRI payload is an on-axis, mirror-based radiometric imager using a beam-splitting optical bench feeding cooled and uncooled detector assemblies. Mechanical and thermal design draws on heritage from instruments developed by EADS Astrium and subcontractors including Thales Alenia Space and Sodern. The instrument uses a rotating mirror scan mechanism to produce full-disk images with a geometric resolution of approximately 3 km at nadir for the visible channel and about 3 km to 6 km for infrared channels. Electronics and data handling were designed to interface with the Meteosat Second Generation platform avionics and the EUMETSAT ground segment, providing telemetry, telecommand, and housekeeping derived from standards used by ESA missions.

Spectral Bands and Products

SEVIRI acquires imagery in 12 spectral channels spanning visible, near-infrared, and thermal infrared wavelengths. Key channels include the 0.6 µm broadband visible for cloud and surface contrast, the 0.8 µm near-infrared for vegetation and aerosol discrimination, the 1.6 µm and 3.9 µm shortwave-infrared for cloud phase and fire detection, and multiple thermal infrared bands near 6.2 µm, 7.3 µm, 8.7 µm, 9.7 µm, 10.8 µm, 12.0 µm, and 13.4 µm for atmospheric sounding, water vapor profiling, and sea surface temperature retrievals. These channels enable generation of operational products such as rapid-scan visible animations for World Meteorological Organization-coordinated nowcasting, cloud mask and cloud type maps used by NOAA and UK Met Office, volcanic ash detection products consumed by ICAO and Icelandic Meteorological Office, and fire-hotspot alerts analogous to products used by NASA and JAXA.

Onboard Calibration and Processing

SEVIRI employs onboard calibration subsystems including solar diffuser-based reflective calibration for solar channels and blackbody references for thermal channels, with thermal control provided by radiator assemblies and thermal blankets developed by aerospace contractors such as RUAG and EADS. The instrument performs radiometric and geometric preprocessing to deliver Level 1 radiance and calibrated radiance counts to the EUMETSAT ground segment. Calibration strategies are coordinated with intercalibration campaigns involving instruments on GOES-R, Himawari, and Metop platforms, enabling cross-validation with community centers such as ECMWF and CAMS.

Data Reception, Distribution, and Applications

SEVIRI data are downlinked via the EUMETSAT broadcast system to regional ground stations, processed into BUFR and NetCDF formats for dissemination through distribution networks including the EUMETCast multicast service and the WMO GTS. End users range from national meteorological services like Météo-France and Met Office to emergency responders in UN OCHA operations, aviation users coordinated by ICAO, and research institutions at University of Reading and DLR. Applications include numerical weather prediction assimilation at ECMWF, nowcasting at MeteoSwiss, wildfire monitoring used by European Forest Fire Information System, and climate monitoring activities supported by Copernicus services.

Mission History and Operational Use

The SEVIRI instrument first entered service with the initial Meteosat Second Generation satellite following a successful Ariane 5 launch. Subsequent flight models have been launched and operated in series to provide continuity, feeding long-term climate archives curated by EUMETSAT and research data centers like CMEMS and CDS. Operational use has included contributions to major events such as monitoring Hurricane systems in the Atlantic Hurricane Season, tracking Saharan dust outbreaks that affected aviation and air quality agencies, and supporting responses to volcanic eruptions monitored by Icelandic Meteorological Office and Met Office ash advisory centers.

Challenges and Limitations

Limitations include reduced spatial resolution away from nadir typical for instruments in Geostationary orbit, calibration drift over multi-year operations requiring cross-calibration with polar-orbiting sensors such as Metop and Suomi NPP, and susceptibility to stray light and instrument degradation from energetic particle environments managed by agencies including ESA and EUMETSAT. Operational constraints also arise from the fixed longitude of geostationary platforms affecting coverage of high-latitude regions and from latency requirements imposed by real-time services coordinated through WMO and national centers.

Category:Spacecraft instruments Category:Earth observation satellites