Applications of adjoint modelling in atmospheric chemistry: sensitivity and inverse modelling

We present two applications of adjoint modelling with the objective of diagnosing and simulating air pollution in an urban atmosphere. The concerned city is Paris and its surroundings. The first application is the sensitivity of an afternoon ozone peak to anthropogenic emissions and reaction rates. We show in particular the diurnal profile of sensitivity. Despite the paper being mostly methodological, some interesting results come out: we show that (i) the ozone peak is mostly sensitive to morning solvent releases and traffic emissions, and (ii) that only a few reactions are sensitive although the chemical mechanism used is fairly complete. The other application is inverse modelling of the ozone concentrations at the boundaries of the region considered. We demonstrate that the boundary concentrations are in good agreement with independent airborne measurements.