THE EFFECTS OF CLOUDS ON AEROSOL AND CHEMICAL-SPECIES PRODUCTION AND DISTRIBUTION .2. CHEMISTRY MODEL DESCRIPTION AND SENSITIVITY ANALYSIS

A modeling study of the effects of cumulus convection on the transform ation and redistribution of chemical species in the troposphere is des cribed. A sulfate chemistry model is coupled with a two-dimensional, m ixed-phase, two-moment microphysics Eulerian cloud model to examine th e importance of different pathways for aqueous sulfate production. The complexation of CH2O with S(IV) was found to be of minor importance i n most of the model cloud, compared with the oxidation of S(IV) by H2O 2 and O-3, while Fe(III)-catalyzed oxidation plays an important role i n aqueous phase sulfate production. Significant redistribution of SO2 from the boundary layer to the middle and upper troposphere was predic ted, with a larger percentage redistributed in cases initialised with chemical fields representative of polluted continental conditions. The sensitivity of the S(IV) production and SO2 redistribution to variati ons in several model parameters is also examined.