Can we gain knowledge on COS anthropogenic and biogenic emissions from a single atmospheric mixing ratios measurement site?

Abstract. Lack of knowledge still remains on many processes leading to COS atmospheric fluxes, either natural such as the oceanic emissions or the vegetation and soil fluxes, or anthropogenic, from industrial activities and power generation. Moreover, COS atmospheric mixing ratio data are still too sparse to evaluate the estimations of these sources and sinks. This study assesses the anthropogenic and biogenic COS fluxes at the regional scale, in the footprint a measurement site in Western Europe, at a seasonal to diurnal time resolution over half a decade. The continuous time series of COS mixing ratios obtained at the monitoring site of Gif-sur-Yvette (in the Paris area) from August 2014 to December 2019 are compared to simulations with the Lagrangian model FLEXPART, transporting oceanic emissions, biogenic land fluxes from the process-model ORCHIDEE and anthropogenic emissions by two different inventories. The anthropogenic emission inventory based on reported industrial emissions and the characteristics of coal power plants in Europe is consistent with the observations. The flat temporal variability applied to anthropogenic fluxes due to lack of information on industrial and power-generation activity in viscose factories and coal-power plants and the potential mismatches in the representation of the plumes emitted from these hot-spots in the model are the main limitations of this inventory. We find that the net ecosystem COS uptake simulated by ORCHIDEE is underestimated in winter at night, which suggests improvements in the parameterization of the nighttime uptake by plants for COS.