Sentinel-5p, the Atmospheric Composition Sentinel Pioneer
The European Earth Observation programme Copernicus contributes several atmospheric composition sounders to the constellation of satellites being deployed by international space agencies for the coordinated global monitoring of air quality, climate forcing, stratospheric ozone, and environmental hazards.
Launched in October 2017 aboard the Low Earth Orbit (LEO) Sentinel-5 Precursor satellite (hereafter Sentinel-5p), TROPOspheric Monitoring Instrument (TROPOMI) measures daily, on the global scale, and at the unprecedented horizontal resolution of 3.5 x 5.5 km², the atmospheric abundance of O₃, NO₂, HCHO, SO₂, CO, CH₄, clouds, aerosols, and other constituents of interest. Sentinel-5p paves the way to the series of three Sentinel-5 instruments which, from 2023 till 2045, will monitor from similar LEO orbits and on the same daily frequency the distribution and evolution of these constituents.
Complementarily, two Sentinel-4 geostationary satellites (GEO), to be launched respectively in 2023 and 2031, will provide hourly monitoring of atmospheric composition over Europe. Dedicated to the global monitoring of CO2 and CH4 emissions, the high priority candidate Sentinel mission CO2M (Copernicus Anthropogenic Carbon Dioxide Monitoring) will also provide measurements of air quality related species like NO2 and aerosols.
Quality Assurance of Data Production
Developed partly at BIRA-IASB, the data processors and quality assurance systems for the atmospheric Sentinels rely on several heritage missions like GOME, SCIAMACHY and GOME-2.
In recent years these processors and systems have been updated and tailored to respond to more and more stringent requirements. Special care has been given to the quality assurance and operationalisation of the data processing chains to ensure compliance with the needs of the Copernicus information services, and interoperability with other missions of the satellite constellations.
Operational Quality Assessment for Sentinel-5p
Procured by an international consortium commissioned by ESA and supported by The Netherlands, Germany and Belgium, the Sentinel-5p Mission Performance Centre (MPC) provides an operational response to the Copernicus Sentinel mission requirements for:
- quality control
- end-to-end system performance monitoring.
In particular, the Sentinel-5p MPC delivers the TROPOMI operational validation service, which relies on the Validation Data Analysis Facility (VDAF) hosted at BIRA-IASB. VDAF evaluates routinely the quality of TROPOMI data with respect to Fiducial Reference Measurements (FRM) generated by ESA’s FRM programme and collected from ground-based monitoring networks contributing to WMO’s Global Atmosphere Watch.
Operational validation of TROPOMI data is documented on the Validation Data Analysis Facility Portal (http://mpc-vdaf.tropomi.eu). Lessons learnt from the Sentinel-5p operational quality assessment are instrumental in designing operational validation services for the following atmospheric Sentinels and for the international satellite constellations.