Model simulation of the amount of soluble mass during cloud droplet formation

The development of the amount of hygroscopic material from nitric acid vapour in nascent cloud droplets has been studied. This phenomenon was approached first by simple calculations in order to find out maximum values of condensed hygroscopic material in droplets and in cloud water. Then, a more detailed parcel model with the binary condensation of water and nitric acid vapours was used for the simulations of the development of droplet distribution and the composition of droplets. In the parcel model vapours are condensing on the ammonium nitrate particles. According to the results of this study condensation of nitric acid could increase considerably the amount of nitrate ions in the droplets, if we compare this to the amount of nitrate ions from ammonium nitrate salt. This can lead to the enhanced amount of activated cloud droplets.