Modelling the thermodynamic properties of multicomponent aerosol particles.
To address the complexities arising from mixed inorganic / organic aerosol particles a range of rigorous physical chemistry models has been developed to predict their equilibrium composition. The single particle model ADDEM (Aerosol Diameter Dependent Equilibrium Model) has undergone continuous National Centre for Atmospheric Sciences (NCAS)-funded development over several years, primarily as a tool for analysing the interaction between aerosols and atmospheric water vapour. The model may be used as a benchmark for less detailed code and more details about ADDEM may be found here. Recent work has included an analysis of our ability to model mixed surface tensions; a critical parameter for predicting how an aerosol particle activates into a cloud droplet. Whilst the current model serves a benchmark for simplified schemes, its use in larger scale prognostic models is limited by its complexity and poor computational efficiency. An active area of activity is the development of reduced schemes which retain a high level of accuracy yet can be used to predict equilibrium compositions and gas phase / aerosol interactions in large scale models. Details of this work can be found here. This work is being driven by NCAS PDRA Dave Topping.
