Chapter 1.3 Inverse modeling of local surface emissions with the CHIMERE-adjoint model: The case of the Paris area during the ESQUIF field experiment

The aim of this study is to define, test and apply a methodology to optimize surface emissions of anthropogenic species such as NO_x at a local scale by using routine measurements of the air quality monitoring networks (measurements available in numerous areas and for long periods). A new methodology in which analyzed maps of concentrations obtained through a kriging technique are used as constraints for the inversion is proposed. The methodology is tested and applied to the Paris area because (i) the kriging technique has been developed for and first applied to this area because of the fully developed AIRPARIF measurement network and (ii) the layout of the area is representative of a simple type of large urbanized area. The NO_x emission fluxes were particularly studied because (i) they are ozone precursors with large uncertainties, particularly in their 24-h time profile (Vautard et al., 2003) and (ii) they are directly linked to NO concentrations that are measured by AIRPARIF and can be analyzed by kriging.