Monitoring aerosols over Europe: an assessment of the potential benefit of assimilating the VIS04 measurements from the future MTG/FCI geostationary imager

Abstract

Abstract. The study assesses the possible benefit of assimilating Aerosol Optical Depth (AOD) from the future spaceborne sensor FCI (Flexible Combined Imager) for air quality monitoring in Europe. An Observing System Simulation Experiment (OSSE) was designed and applied over a 4-months period that includes a severe pollution episode. The study focuses on the FCI channel centred at 444 nm, which is the shortest wavelength of FCI. A Nature Run (NR) and four different Control Runs of the MOCAGE chemistry-transport model were designed and evaluated to guarantee the robustness of the OSSE results. The AOD synthetic observations from the NR were disturbed by errors that are typical of the FCI. The variance of the FCI AOD at 444 nm was deduced from a global sensitivity analysis that took into account the aerosol type, surface reflectance and different atmospheric optical properties. The experiments show a general benefit on all statistical indicators of the assimilation of the FCI AOD at 444 nm for aerosol concentrations at surface over Europe, and also a positive impact during the severe pollution event. The simulations with data assimilation reproduced spatial and temporal patterns of PM10 concentrations at surface better than without assimilation all along the simulations and especially during the pollution event. This work demonstrates the capability of data from the future FCI sensor to bring an added value to the MOCAGE aerosol simulations, and in general, to other chemistry transport models.

Impact of synthetic spaceborne NO<sub>2</sub> observations from the Sentinel-4 and Sentinel-5p platforms on tropospheric NO<sub>2</sub> analyses

“…Atlas, 1997;Atlas et al, 2003) and in the past 10 years have evolved for air quality applications (Timmermans et al, 2015). These OSSEs have focused on aerosols (Descheemaecker et al, 2018;Timmermans et al, 2009;Yumimoto and Takemura, 2013), carbon monoxide (CO) (Abida et al, 2017;Claeyman et al, 2011;Edwards et al, 2009;Yumimoto, 2013) and ozone (Hamer et al, 2011;Zoogman et al, 2011Zoogman et al, , 2014aZoogman et al, , 2014b from either LEO, GEO or a combination of both observing systems.. The review by Timmermans et al, (2015) provides a 5 framework and set of requirements for each step in the framework to ensure realistic evaluation of the benefit of the new instruments.…”