2006), Inverse modeling of emissions for local photo-oxidant pollution: Testing a new methodology with kriging constraints, Annales Geophysicae

For chemistry-transport models operating at regional scales, surface emissions are the input data to which the output concentrations are the most sensitive. They are nevertheless poorly known. The possibility of modifying existing inventories seems therefore promising for better simulation of concentration fields and better understanding of photo-oxidant pollution. The aim of this study was to define a methodology to optimize surface emissions at local scale i.e. to compute correction factors for the available (called first-guess) inventory so that the optimized fluxes of NOx and VOCs minimize the difference between simulated and measured ozone and/or NOy concentrations. A new approach is proposed which is based on the aggregation of several numerical techniques. A kriging method is used to obtain analyzed maps of ozone concentrations, which are then used as constraints for the inversion. Our modeling system is based on CHIMERE chemistry-transport model and its adjoint. It performs 4D-integration. Academic cases were run in order to validate the inverse code and quantify the limitations of the new methodology that is particularly suited to local pollution. 1. Optimizing the emissions: what for