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 sensit ivity studies bearing on changes in ambient relative humidity and vari ous sulfate formation rates, the model is used to calculate cloud drop let nucleation for an ascending air parcel. Using the spectrum obtaine d with the aerosol model initialized with experimentally determined ch emical concentrations, the critical radius thus obtained appears quite realistic. Sensitivity studies on the vertical velocity and on the ae rosol mass concentrations display good agreement with previous publish ed results.