Analysis of regional climate model simulations for Central Europe as a potential tool to assess weather-related air quality conditions

Potentially adverse air quality is discussed via its relation to wind conditions and boundary layer thickness. The main goal of the study is to evaluate different RegCM simulations for 1981–1990, driven by either reanalysis data or global climate model output. Wind speed, temperature, planetary boundary layer (PBL) height and the Holst stagnation index are analysed and compared to the reference data. Wind is overestimated throughout the year. Temperature is overestimated in the plain areas, whereas underestimated in the mountains. The PBL height is generally overestimated and substantial differences are identified between the RegCM4.5 and RegCM4.3 simulations. Consequently, these result in substantial underestimations of the Holst stagnation index and of the frequency of potentially adverse air quality, although the annual cycles are reproduced well. In order to prepare reliable projections, the testing of different model setups must be continued, especially changing the Holtslag scheme to a different PBL parameterisation scheme.