Greenhouse gas retrievals for the CO2M mission using the FOCAL method: first performance estimates

• Published in: Atmospheric measurement techniques 2024-04, Vol.17 (8), p.2317-2334
• Main Authors: Noël, Stefan, Buchwitz, Michael, Hilker, Michael, Reuter, Maximilian, Weimer, Michael, Bovensmann, Heinrich, Burrows, John P, Bösch, Hartmut, Lang, Ruediger
• Format: Article
• Language: English
• Subjects: Aerosols; Air pollution; Algorithms; Anthropogenic factors; Artificial satellites; Atmospheric carbon dioxide; Atmospheric models; Atmospheric monitoring; Carbon dioxide; Cirrus clouds; Climate change; Datasets; Emissions; Gases; Greenhouse gases; International organizations; Launching; Meteorological satellites; Meteorology; Methane; Methods; Monitoring; Nitrogen dioxide; Paris Agreement; Polarimeters; Product quality; Radiance; Radiative transfer; Remote sensing; Retrieval; Satellite constellations; Satellites; Simulation; Spectroscopy; Surface properties; Systematic errors; Trace gases
• ISSN: 1867-8548; 1867-1381; 1867-8548
• DOI: 10.5194/amt-17-2317-2024

The Anthropogenic Carbon Dioxide Monitoring (CO2M) mission is a constellation of satellites currently planned to be launched in 2026. CO2M is planned to be a core component of a Monitoring and Verification Support (MVS) service capacity under development as part of the Copernicus Atmosphere Monitoring Service (CAMS). The CO2M radiance measurements will be used to retrieve column-averaged dry-air mole fractions of atmospheric carbon dioxide (XCO.sub.2 ), methane (XCH.sub.4) and total columns of nitrogen dioxide (NO.sub.2). Using appropriate inverse modelling, the atmospheric greenhouse gas (GHG) observations will be used to derive United Nations Framework Convention on Climate Change (UNFCCC) COP 21 Paris Agreement relevant information on GHG sources and sinks. This challenging application requires highly accurate XCO.sub.2 and XCH.sub.4 retrievals. Three different retrieval algorithms to derive XCO.sub.2 and XCH.sub.4 are currently under development for the operational processing system at EUMETSAT. One of these algorithms uses the heritage of the FOCAL (Fast atmOspheric traCe gAs retrievaL) method, which has already successfully been applied to measurements from other satellites. Here, we show recent results generated using the CO2M version of FOCAL, called FOCAL-CO2M.