Keywords: dry deposition model, photochemical air pollution model, root-zone soil water content, ozone, stomatal flux, air quality, Hungary, soil wetness, soil moisture
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 soil water deficiency can strongly reduce the stomatal conductance and hence the ozone flux through it.