Nonstationary homogeneous nucleation in the atmosphere — a numerical solution

Abstract

The present study deals with the problem of nonsteadiness of the formation process of a new phase in the atmosphere. Using a numerical method, the solution of the main kinetic equation of phase formation is found in the cases of nonstationary homogeneous condensation, deposition and freezing. The results obtained are compared with those derived by the analytical approach, and the advantages of the numerical solution are stressed. The differences between the time characteristics of the nonstationary phase formation process, delay time τ n , transient time t n , effective time lag θ n and induction time or time lag τ are pointed out. The period of nonsteadiness is shown as being essential in the process of formation of a new phase in the atmosphere, which has to be thoroughly studied. It is emphasised that the numerical approach is also applicable to over-critical sizes, i.e. it is applicable in order to obtain the description of the process of condensational growth leading to the formation of visible clusters under experimental conditions. This provides a possibility for immediate comparison between theory and experiment.