On the Moment Method for the Modeling of Cloud Microphysics in Rarefied Turbulent Atmospheres: I. Condensation and Mixing

A compact and efficient method for the description of microphysics and dynamics of condensational clouds in planetary atmospheres is proposed. It is based on the representation of the aerosol size distribution in terms of its moments. The method is justified, and different ways for closing the chain of moment equations and constructing numerical schemes are discussed. Simulations performed with the method of moments are compared to grid simulations. In a wide range of parameters, the accuracy of the method of moments is on the order of or better than 15–20%, which is comparable to or better than the accuracy of grid methods at low resolution. The method was successfully applied to the modeling of global circulation in the Martian atmosphere.