Sensitivity of cloud condensation nuclei activation processes to kinetic parameters

The activation of cloud condensation nuclei to form cloud drops can be a kinetically limited process under some circumstances. Here the sensitivity of particle activation to parameters that are related to kinetic processes, in particular condensational growth and ambient supersaturation, is examined. Specifically, the parameters studied are the thermal and mass accommodation coefficients, the rate of solute dissolution for a particle, and the updraft velocity. Results are based on the equation for condensational growth and simulations using adiabatic parcel models. We conclude that activation is not very sensitive to the thermal accommodation coefficient but is sensitive to the mass accommodation coefficient below some critical value of ∼0.1 to 0.001. Dissolution rates (defined for 100 nm dry particles) in the range of 10 min to 1 day can significantly affect activation. Sensitivity to updraft velocity uncertainties can be significant and are likely to be more important for polluted rather than clean conditions.