Adaptation of a cloud activation scheme to a spectral-chemical aerosol model

Development and preliminary tests of a cloud activation scheme adapted to a spectral-chemical aerosol model are presented. After some sensitivity studies bearing on changes in ambient relative humidity and various sulfate formation rates, the model is used to calculate cloud droplet nucleation for an ascending air parcel. Using the spectrum obtained with the aerosol model initialized with experimentally determined chemical concentrations, the critical radius thus obtained appears quite realistic. Sensitivity studies on the vertical velocity and on the aerosol mass concentrations display good agreement with previous published results.