Satellite remote sensing of global greenhouse gas (GHG) concentrations provides invaluable information on GHG sources and sinks, supporting efficient climate mitigation policies. Recently, the accuracy targets of upcoming GHG satellite missions (MERLIN, CO2M) have become increasingly stringent (e.g., 2 ppb of XCH₄ and 1 ppm of XCO₂). The proposed research will greatly improve the accuracy of underlying spectral line parameters for satellite GHG retrievals and validate this accuracy with AirCore and ground-based observations. This will establish traceability to the SI and improve data comparability and trustworthiness among GHG satellite missions. Furthermore, it will generate equivalence among ground-based sites, and considerably reduce costs on aircraft calibrations

The contribution of Empa’s E&I group will focus on improving spectral fitting algorithms and interference correction to realize more accurate stable isotopes (¹³CO₂/¹²CO₂, C¹⁸O¹⁶O/C¹⁶O¹⁶O) and radiocarbon (¹⁴CO₂/¹²CO₂) analysis in atmospheric CO₂.