High resolution mapping of total deposition of acidifying pollutants

A framework has been developed to estimate dry and wet deposition over Southern Belgium for a variety of acidifying substances on a 5 × 5 km2 grid. Concentrations of different compounds in the atmosphere or in the precipitation are provided by the measurement networks (both stations and gauges) and are interpolated over Southern Belgium. Dry deposition velocities are calculated using local meteorology and land use information, following the approach described in Zhang et al. (2001, 2003). Local precipitation is provided by merged radar-gauge observations. This is the first high resolution framework for Southern Belgium computing both time- and space-dependent deposition, using a modified kriging interpolation method (for SO2 and NO2), as well as radar-based precipitation. Estimated dry and wet depositions are compared with long range transport (LRT) model results, based on the European emission inventories. Although a good agreement is observed between our results and LRT model results on the annual totals averaged over Southern Belgium, the extent of agreement for the spatial variability of the annual deposition differs significantly from one pollutant to another. This new framework provides consistent high resolution maps for several pollutants, while improving the mapping of dry and wet deposition in Southern Belgium, in order to assess critical loads exceedances.