IMPACT OF CLOUD DYNAMICS ON TROPOSPHERIC CHEMISTRY - ADVANCES IN MODELING THE INTERACTIONS BETWEEN MICROPHYSICAL AND CHEMICAL PROCESSES

A chemical module describing the tropospheric photochemistry of ozone precursors in both gaseous and aqueous phases for a remote continental atmosphere has been developed within the framework of a two-dimensional cloud model. Dynamical, microphysical and chemical processes are fully interacting in order to study the influence of clouds on ozone chemistry and to quantify the relative importance of the different processes on the budget and evolution of 12 chemical species. Whereas the concentrations of highly soluble species are strongly affected by evaporation and sedimentation, less soluble species are affected primarily by accretion. The model reproduces previously observed chemical phenomena such as the enrichment of formic acid at the top of the cloud.