A trajectory-grid approach for solving the condensation and evaporation equations of aerosols

The trajectory-grid method (Chock et al., Atmospheric Environment 30 (1996) 857–868) for solving the transport equation in a grid model can be easily adapted to solve the condensation/evaporation equations of internally mixed multicomponent aerosols based on the sectional approach. Compared to the Bott scheme (Monthly Weather Review 117 (1998) 1006–1015, 2633–2636) often used for solving these equations, the method is significantly more accurate, of comparable speed, but gaining in speed as the number of aerosol components increases. Most notably, there is no mismatch in size change of the different components of the same aerosol. The method is quite flexible, can handle an abrupt change in aerosol size due to evaporation of fog particles, and is ideal for multiply-parallel processors.