AN APPROACH TO ZOOM MODELING OF ACID DEPOSITION ON THE BASIS OF SULFUR COMPOUND EVALUATION FOR THE ST. PETERSBURG REGION

One of the problems of atmospheric pollution modelling in industrial r egions is a harmonization of local and regional modelling results. For many European domains, deposition from remote emitters may be as much as half of the total. A modelling activity aimed at solving this prob lem is presented. A model with variable spatial and temporal resolutio n is used. It is based on the current model of MSC-E for acid compound s and could operate with grid cell size from 25 km x 25 km to 150 km x 150 km. Special methodology applied to the model provides automatic r escaling of necessary parameters and then adjustment for the grid size used. The reasons for some disagreement between local and regional re sults are discussed. As an example, the results of the model applicati on to North-East Europe is considered. The calculation domain is chara cterized by high non-uniformity of source distribution, high values of local emissions, and intense impact from distant emitters. Results of model runs showed that changing the spatial and temporal resolution b y the factor of 6 may lead to redistribution of the deposition by the factor of 10. This effect is significant even for long-term multiannua l calculations.