Evidence of the aerosol core-shell mixing state over Europe during the heat wave of summer 2003 by using CHIMERE simulations and AERONET inversions

International audience; The aim of this work consists to infer the most probable mixing state of aerosols over the European continent during the heat wave of summer 2003, where large concentrations of biomass burning and anthropogenic aerosols have been observed. The methodology presented here is based on the Single Scattering Albedo (SSA) sensitivity to the mixing state of particles. Three different mixing cases; external mixing, internal mixing, and core-shell type mixing have been considered. Composite SSA has been computed for this intense pollution event over Europe and are compared with the AErosol RObotic NETwork (AERONET) retrieved SSA values. The most probable mixing state seems to be core-shell mixing, with secondary aerosols coating over primary soot and mineral dust. This work underlines clearly that this specific representation should be used in modeling exercises for simulating anthropogenic and/or biomass burning direct and semi-direct aerosol effects and climate impact over the European region.