Modeling formation of SOA from cloud chemistry with the Meso-NH model: Sensitivity studies of cloud events formed at the puy de Dôme Station

Abstract

The majority of the organic fraction of aerosols is suspected to be of secondary origin. However, the sources, chemical composition and formation mechanisms of secondary organic aerosols (SOA) remain one of the least understood processes relevant to the atmosphere. Laboratory experiments, in situ measurements and numerical simulations recently highlighted the formation of SOA through aqueous chemistry in humid aerosol particles and in cloud droplets. However, there is still a need to evaluate the relative relevance of SOA formation through aqueous chemistry in comparison to classical gas to particles conversion pathways. Cloud resolving model (CRM) allows simulating the complex aerosols-cloud-chemistry interactions. Meso-NH (Mesoscale Non-Hydrostatic atmospheric model) CRM model includes a cloud chemistry module and an aerosol module, which allows representing the formation of SOA due to aqueous phase reactivity. The model is applied on a cloud event observed at the puy de Dôme Mountain. Comparing simulations with or without the cloud chemistry module activated assesses the contribution of the cloud chemistry in the SOA formation. Results show a significant contribution of aqueous phase reactivity in the formation of SOA downstream the Mountain.