Metop (Meteorological Operational satellite) is a series of three polar-orbiting meteorological satellites developed by the European Space Agency (ESA) and operated by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). The satellites form the space segment component of the overall EUMETSAT Polar System (EPS), which in turn is the European half of the EUMETSAT / NOAA Initial Joint Polar System (IJPS). The satellites carry a payload comprising 11 scientific instruments and two which support Cospas-Sarsat Search and Rescue services. In order to provide data continuity between Metop and NOAA Polar Operational Environmental Satellites (POES), several instruments are carried on both fleets of satellites.
Metop-A, launched on 19 October 2006, is Europe's first polar orbiting satellite used for operational meteorology. With respect to its primary mission of providing data for Numerical Weather Prediction, studies have shown that Metop-A data are measured as having the largest impact of any individual satellite platform on reducing 24-hour forecasting errors, and accounts for about 25% of the total impact on global forecast error reduction across all data sources.
Each of the three satellites were originally intended to be operated sequentially, however good performance of the Metop-A and Metop-B satellites mean there was a period of all three satellite operating. EUMETSAT lowered the orbit of Metop-A and decommissioned the spacecraft in November 2021
The successor to the Metop satellites will be MetOp-SG, currently with the first MetOp SG-A satellite expected to be launched in 2025.
Instruments
The following instruments are flown on board the Metop satellites:
Shared instruments
The following instruments are shared on the NPOES satellites which form the U.S. contribution to IJPS: AMSU-A1/AMSU-A2 – Advanced Microwave Sounding Units HIRS/4 – High-resolution Infrared Radiation Sounder (N.B. Not included on Metop-C) AVHRR/3 – Advanced Very High Resolution Radiometer Argos A-DCS – Advanced Data Collection System SEM-2 – Space Environment Monitor SARP-3 – Search And Rescue Processor (N.B. Not included on Metop-C) SARR – Search And Rescue Repeater (N.B. Not included on Metop-C) MHS – Microwave Humidity Sounder
Metop specific instruments
The following instruments are flown exclusively on the Metop satellites: IASI – Infrared Atmospheric Sounding Interferometer GRAS – Global Navigation Satellite System Receiver for Atmospheric Sounding ASCAT – Advanced SCATterometer GOME-2 – Global Ozone Monitoring Experiment-2
Background
Metop has been developed as a joint undertaking between the European Space Agency (ESA) and European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). Recognising the growing importance of Numerical Weather Prediction (NWP) in weather forecasting, Metop was designed with a suite of instruments to provide NWP models with high resolution global atmospheric temperature and humidity structure. Data from Metop are additionally used for atmospheric chemistry and provision of long term data sets for climate records.
Metop heritage
The Metop satellites have a modular construction, comprising a Service Module, a Payload Module and a suite of instruments.
A SPOT heritage service module provides power (via solar array and five batteries for eclipse), attitude and orbit control, thermal regulation and Tracking, Telemetry and Command (TT&C). An Envisat heritage payload module provides common command and control and power buses for the instruments along with science data acquisition and transmission.
The suite of instruments are largely derived from precursors flown on the European Space Agency's European Remote-Sensing Satellite ERS / Envisat satellites or are fully recurrent units originally developed for NOAA's Television Infrared Observation Satellite (TIROS) series of polar-orbiting satellites.
Data acquisition
With the exception of Search and Rescue (SARSAT), which is a purely local mission with its own dedicated transmitter, all data from the MetOp Instruments are formatted and multiplexed by the Payload Module and either stored on a solid-state recorder for later transmission via an X-Band antenna, or directly transmitted to local users via High Rate Picture Transmission (HRPT) L-Band antenna.