The Copernicus CO2M mission for monitoring anthropogenic carbon dioxide emissions from space

The European Space Agency (ESA), in collaboration with the European Commission (EC) and EUMETSAT, is developing a space-borne observing system for quantification of anthropogenic carbon dioxide (CO2) emissions. Forming part of the EC's Copernicus programme, the CO2 monitoring (CO2M) mission will be implemented as a constellation of identical satellites, to be operated over a period > 7 years and measuring CO2 concentration in terms of column-averaged mole fraction (denoted as XCO2). Each satellite will continuously image XCO2 along the satellite track on the sun-illuminated part of the orbit, with a swath width of >250 km. Observations will be provided at a spatial resolution < 2 x 2 km2 near the swath center, with high precision (<0.7 ppm) and accuracy (bias <0.5 ppm). To this end, the payload comprises a suite of instruments addressing the various aspects of the challenging observation requirements: A push-broom imaging spectrometer will perform co-located measurements of top-of-atmosphere radiances in the Near Infrared (NIR) and Short-Wave Infrared (SWIR) at high to moderate spectral resolution (NIR: 747-773nm@0.1nm, SWIR-1: 1595-1675nm@0.3nm, SWIR-2: 1990-2095nm@0.35nm). These observations are complemented by measurements in the visible spectral range (405-490 nm@0.6nm), providing vertical column measurements of nitrogen dioxide (NO2) that serve as a tracer to assist the detection of fossil-fuel emission plumes (e.g. from coal-fired power plants and cities). High quality retrievals of XCO2 will be ensured even over polluted industrial regions, thanks to co-located measurements of aerosols performed by a Multiple-Angle Polarimeter (MAP). Finally, measurements of a three-band Cloud Imager, co-registered with the CO2 observations, will provide the required cloud-flagging capacity at sub-sample level (<200m resolution). The presentation will review the results of the Phase A/B1 instrument studies carried out in 2018-2019, including technology pre-development activities, and highlight the identified engineering challenges. The preliminary design of the CO2M mission’s instruments at the beginning of the implementation phase will be presented, along with an outlook on the development activities under the Phase B2CD programme.