First validation of the CAMS greenhouse gas system with IAGOS aircraft measurements of CO2 and CH4

IAGOS (In-service Aircraft for a Global Observing System) is a European Research Infrastructure for global observations of atmospheric composition using commercial aircraft. Commercial aircraft are ideal platforms for providing long-term in-situ measurements with high vertical and temporal resolution, particularly at cruise altitude (between 9 and 13 km) in the climate-sensitive region of the atmosphere known as the upper troposphere-lower stratosphere (UTLS) and throughout the depth of the troposphere during the landing and take off phases of the flights.  Fully automated instruments are permanently installed on Airbus A330 aircraft operated by different airlines. Data are collected on about 500 flights per aircraft per year. The aircraft measure the abundances of many essential climate variables and the data are transmitted in near real time to weather services and are freely available for the scientific community, national air quality prediction centres and the Copernicus Atmosphere Monitoring Service (CAMS).  The data are routinely used to validate the operational ECMWF chemical forecasting model through the CAMS-84 project.  Up to now this effort has focused on reactive gases and water vapour. New to IAGOS are the measurements of the greenhouse gases (GHG),  CO2 and CH4.  We present the first comparison of the CAMS GHG system  (Global analyses and high resolution forecasts of greenhouse gases) with the new IAGOS CO2 and CH4 measurements and  show how this  will  be part of  the future validation of the CAMS operational model.