Atmospheric Composition Monitoring with MOPITT and IASI: CO, a Tracer of Pollution

Carbon monoxide (CO) is an important trace gas for understanding air quality and atmospheric composition. It is a good tracer of pollution plumes and atmospheric dynamics. In this presentation we analyse the global and regional CO distributions as seen by remote sensors onboard of satellites, in particular the nadir-looking thermal infrared MOPITT/Terra and IASI/MetOp instruments. Since several years of data are now available, we show CO distributions over polluted and clean regions for the period 2008-2013, and we discuss their evolution with time. A detailed analysis was performed to compare both datasets and we show the influence of the a priori assumptions in the retrieval process. We did a retrieval experience where the MOPITT retrieval code was run on the MOPITT dataset using the IASI a priori profile and covariance matrix. The agreement for total columns and profiles distributions is discussed, and the retrieved profiles are validated with aircraft IAGOS data. Finally, we will also describe how MOPITT and IASI data are routinely assimilated in the Monitoring Atmospheric Composition and Climate (MACC) system (the pre-operational Copernicus Atmosphere Service of the European Union), which provides analyses and forecasts of global CO distributions.