Modeling and measurements of the ABL in Sofia, Bulgaria

Sofia (Bulgaria) has very high ground level concentrations of PM both in winter and summer, due to the high anthropogenic emissions and frequent stagnant meteorological conditions that characterize this area. It is important to use Air Quality Modeling Systems for this area integrating chemical transport models, emission models, meteorological models and initial and boundary condition processors. Meteorological models are core modules of these Systems and, due to their complexity, require high computational costs to perform simulations. Evaluation of the model performance over the area is a key issue that is rarely met, especially concerning comparisons of modeled and measured vertical profiles of meteorological parameters.

This paper presents the results obtained in the frame of the HPC-EUROPA (Pan-European Research Infrastructure on High Performance Computing) cooperation project. The meteorological fields over Sofia have been simulated using RAMS (Regional Atmospheric Modeling System) through parallel computing. The meteorological simulations have been calculated considering different RAMS model versions, nested grid configuration and spatial resolutions. The evaluation of the model results is then performed against boundary-layer experimental measurements, using radio-sounding and surface data collected in the area from September to October 2003. Bulgaria.