A parameterization of cloud droplet nucleation. Part II: Multiple aerosol types

A parameterization of cloud droplet nucleation for a single, log-normally distributed, aerosol type is generalized to the case of multiple aerosol types with differing size distributions and compositions. The parameterization accounts for the competition between different aerosol types as cloud condensation nuclei, and the dependence of the competition on the number concentration, composition and size distribution of each aerosol type. Comparisons with detailed numerical solutions indicate typical differences of 50% and 20% for the number fraction and mass fraction, respectively, of aerosols activated for each type.