Róbert Mészáros

The Simulation of Photochemical Smog Episodes in Hungary and Central Europe Using Adaptive Gridding Models

An important tool in the management of photochemical smog episodes is a computational model which can be used to test the effect of possible emission control strategies. High spatial resolution of such a model is important to reduce the impact of numerical errors on predictions and to allow better comparison of the model with experimental data during validation. This paper therefore presents the development of an adaptive grid model for the Central European Region describing the formation of photochemical oxidants based on unstructured grids. Using adaptive methods, grid resolutions of less than 20 km can be achieved in a computationally effective way. Initial simulation of the photochemical episode of August 1998 indicates that the model captures the spatial and temporal tendencies of ozone production and demonstrates the effectiveness of adaptive methods for achieving high resolution model predictions.

Effect of the soil wetness state on the stomatal ozone fluxes over Hungary

A coupled Eulerian photochemical reaction-transport model and a detailed ozone dry deposition model have been utilised for the estimation of stomatal ozone fluxes over Hungary. Ozone concentrations were modelled on an unstructured triangular grid using a method of lines approach to the solution of the reaction−diffusion−advection equations describing ozone formation, transport and deposition. The model domain covers Central-Europe including Hungary, which was located at the centre of the domain and covered by a high resolution nested grid. The dry deposition velocity of ozone was calculated based on the aerodynamic, quasi-laminar boundary layer and canopy resistance. The effect of soil water content on the stomatal ozone flux was analysed. The stomatal ozone flux calculations were performed for two cases, with and without taking into account the effect of the soil moisture stress on the ozone deposition. The meteorological data were generated by the ALADIN meso-scale limited area numerical weather prediction model. It was found that

Modelling Photochemical Air Pollution in Hungary Using an Adaptive Grid Model

An adaptive grid model, describing the formation of photochemical oxidants based on triangular unstructured grids, has been developed for the Central European Region. The model automatically places a finer resolution grid in regions were higher numerical error is predicted by the comparison of 1st and 2nd order solutions. Using this method, grid resolutions of the order of 15 km could be achieved in a computationally effective way. Initial simulation of the photochemical episode of August 1998 indicate that the model captures well the spatial and temporal tendencies of ozone production.