Multi-species inversion of CH<sub>4</sub>, CO and H<sub>2</sub> emissions from surface measurements
Abstract. In order to study the spatial and temporal variations of the emissions of greenhouse gases and of their precursors, we developed a data assimilation system. It is based on the atmospheric chemical transport model LMDz and on a simplified scheme for the oxidation chain of hydrocarbons, including methane, formaldehyde, carbon monoxide and molecular hydrogen together with methyl chloroform. Inversions of the emission fluxes of CO, CH4 and H2 and concentrations of HCHO and OH were performed for the year 2004, using surface concentration measurements as constraints. Independent data from satellite retrievals are used to evaluate the realism of the results. The total emitted mass of CO is 30% higher after the inversion and the spatial distribution of emissions of CH4 is modified by an increase of fluxes in boreal areas. The comparison between mono- and multi-species inversions shows that the results are close at a global scale but may significantly differ at a regional scale because of the interactions between the various tracers during the inversion.