Modal aerosol dynamics model for Europe: development and first applications

The Modal Aerosol Dynamics model for Europe (MADE) has been developed as an extension to mesoscale chemistry transport models to allow a more detailed treatment of aerosol effects in these models. Due to the complexity of the atmospheric aerosol system an approach has been chosen which is, on the one hand, fast enough for this application and, on the other, provides sufficient information on the particle size distribution. In MADE, which is developed from the regional particulate model (RPM) the particle size distribution of the submicrometer aerosol is represented by two overlapping lognormal modes. The chemical composition is currently treated in the sulfate–nitrate–ammonium and water system. Sources for aerosol particles are modelled through nucleation and emission. Coagulation, condensation, transport and deposition are considered as processes modifying the aerosol population in the atmosphere. Aerosol dynamics calculations are performed on-line within the chemistry-transport model. Process studies with a one-dimensional version of the model system are used to investigate the relative importance of the individual aerosol dynamic processes and the important links between between the gas and aerosol phase as well as meteorological parameters. Results from a first three-dimensional application of the fully coupled system of MADE and the European Air Pollution Dispersion model system (EURAD) are presented, showing the suitability of MADE as an aerosol dynamics model even within complex air quality models. The application of the new aerosol model provides information on particle number, size and surface area in addition to the chemical concentration fields, which can be used to study a variety of aerosol-related air pollution issues in subsequent studies.