Simulations of warm cloud microphysics with a particle-based multicomponent model

A particle-based cloud microphysical model which explicitly resolved the composition of individual droplets with multiple compositions is developed. The model accurately tracks the evolution by activation, condensation and coalescence of individual droplets with internally mixed aerosols. The evolution of the drop population by coalescence is calculated with the stochastic algorithm of Gillespie (1976) for chemical reactions, in the formulation proposed by Laurenzi and Bartlett (2002). For the four-component case (droplet mass and three types of internally mixed aerosols) the model was applied to model the microphysical evolution of a wave cloud, with good results that illustrate the potential of this modeling approach.