Objectives
The specific scientific objectives of SUB-AERO are the following:
- to evaluate and assess the physical, chemical and meteorological processes responsible for the spatial and temporal variability of photochemical pollutants and fine particles in subgrid and their effect on their long-range transport characteristics. In this task we will evaluate the importance of mixing/transformation interactions, and the adequacy of existing modeling methods, for photochemical/fine particle air pollution systems, using the extensive field data which will be obtained from the experimental part of our research proposal and also from other available field data from previous studies on gas and aerosol phase pollutants.
- to obtain and provide to the scientific and policy-maker community in Europe a critical data base on the vertical and horizontal distribution of ozone and fine particle concentrations together with meteorological conditions to allow interpretation of the contributions from local and distant sources to their ambient pollution concentrations.
- to evaluate methods (often developed in different scientific and technical fields) available for assessing the effects of turbulent mixing on physical and chemical transformations, from the perspective of their applicability in the framework of current and future generation mesoscale air quality models. Field measurements will provide a comprehensive data set for comparison proposes. Emission inventory data for photochemical gases and aerosols already compiled from international and national efforts for Europe will be used in the mesoscale modelling efforts (TNO, 1997).
- to investigate the importance of new particle formation and fate in subgrid scale as well as their chemical composition in the Mediterranean area under different meteorological conditions and seasons (summer and winter). This task will be achieved with a combination of detailed extensive field studies. Field campaigns will focus on the evolution of aerosol number and mass (for selected species) size distribution with respect to the observed concentrations of precursor (NOx, SO2, O3) and equilibrium (NH3, NOy) gases. Measurements will be performed by SMPS, OPC, Cascade impactors, virtual impactors, annular denuders and gas analysers. Modeling tools (as the classical nucleation theory for binary and multicomponent mixtures in combination with the MM5 (meteorological model) and UAM-AERO (air quality photochemistry-aerosol model) frameworks).
- to develop (or refine as necessary), and test a modified CB-IV (and eventually EMEP) chemistry module including secondary aerosol and ozone formation and mesoscale air quality models (UAM-AERO), based on findings from the present project and other on-going research developments on the understanding of atmospheric chemistry of ozone and secondary PM as well as in turbulent transport, kinetic theories and atmospheric mixing. The information obtained by computationally intensive methods, such as second order turbulent closure and Large Eddy Simulations (LES), will be used to evaluate simpler parameterizations of mixing/transformation interactions and for developing and testing practical computational tools such as versatile Plume-In-Grid Model and a module linking a Large Eddy Simulation model with Chemistry and Aerosol Dynamics.
