MetOp overview
Polar orbiting missions are vital for both operational meteorology and climate monitoring as they provide global observations on a regular and consistent basis.
The United States is currently operating polar-orbiting meteorological satellites in four sun-synchronous orbital planes, for two services: an early morning and afternoon pair of military satellites (DMSP) and a mid-morning and afternoon civil pair, Television Infrared Observation Satellite (TIROS).
The POES (Polar Operational Environmental Satellites) programme operated by the United States National Oceanic and Atmospheric Administration (NOAA) is in charge of the American civil (TIROS) programme.
The Initial Joint Polar System (IJPS) is a co-operative agreement between the European Organisation for the Exploitation of Meterological Satellites (EUMETSAT) and NOAA to replace the POES mid-morning service by an equivalent European service – the EUMETSAT Polar System (EPS). The MetOp satellites have been developed for this purpose.
In order to fulfil the mission objectives, MetOp carries out the following missions:
- Operational Meteorology
- Climate monitoring
Additional missions are:
- Space Environmental Monitoring (SEM)
- Humanitarian service (Search and Rescue)
The Operational Meteorology Mission provides the morning service of the Polar Orbiting Environmental Satellite (POES) system.
The Climate Monitoring Mission is related to the global study and monitoring of the Earth's climate system. International co-operation programmes such as the Global Climate Observing System (GCOS), the International Geosphere-Biosphere Programme (IGBP) and the World Climate Research Programme (WCRP) endorse this.
MetOp is the space segment of the EUMETSAT Polar System (EPS) and represents the first European polar-orbiting satellite dedicated to operational meteorology. For the user community, it is essential that EPS data provide continuity and commonality to the primary mission results associated with the POES era. A POES meteorological instrument package will be accommodated on MetOp-1 and MetOp-2. This will generate similar data as the 13:30h afternoon orbit covered by NOAA-N and N' satellites. The MetOp orbit is at a mean local solar time of 09:30h. This dual system provides global data sets every six hours.
The combination of instruments on board MetOp has remote sensing capabilities to observe the Earth by day and night as well as under cloudy conditions.
European instruments
The MetOp concept will greatly enhance data quality with a new generation of European instruments:
- ASCAT (Advanced SCATterometer)
- GRAS (GNSS Receiver for Atmospheric Sounding)
- GOME-2 (Global Ozone Monitoring Experiment 2)
- IASI (Infra-Red Atmospheric Sounder Interferometer)
These instruments offer advanced sounding capabilities, the measurement of ocean surface wind as well as improved observation of ozone and other trace gases. Besides providing complementary data for meteorology, the European contribution will lead to a better understanding of our climate. MetOp also accommodates a suite of American instruments that matches the instruments provided by NOAA. This ensures data continuity to the meteorological community.
The meteorological instrument package will be used to establish three-dimensional fields of temperature and humidity through the Earth's atmosphere for operational, numerical weather prediction models (NWP). The imaging capability will include cloud coverage for weather forecasting and sea surface temperature.
The selection of a low Earth orbit ensures high-resolution data from the instrument suite. The solar incidence angle on the Earth's surface associated with a morning or afternoon polar orbit provides good contrast and shadow conditions for global imagery.