A regional model of European aerosol transport: Evaluation with sun photometer, lidar and air quality data

Aerosol transport simulations within Europe were performed with the regional transport model COSMO-MUSCAT for two different time periods, July 19–26, 2006 and February 16–26, 2007. Simulated PM2.5, backscatter profiles and aerosol optical depths (AODs) were compared to observations, showing good agreements in magnitude, shape and day-to-day variations. Maximum AODs (>0.4) were found over Middle Europe and minimum AODs (<0.13) over the ocean during both time periods, corresponding to regions of high (PM2.5 > 10 μg m−3) and low (PM2.5 < 4.0 μg m−3) concentration near the surface. Vertical aerosol distributions were evaluated with lidar measurements from the EARLINET ground network and CALIPSO satellite retrievals. The characteristic vertical distribution and the differences for the summer and the winter cases were represented well by the regional model. Mean differences between −5.0 × 10−7 to−2.0 × 10−7 m−1 sr−1 (summer case) and −2.3 × 10−6 to 1.0 × 10−6 m−1 sr−1 (winter case) from 0.0 to 2.5 km altitude were found between observed (space-based lidar) and simulated backscatter coefficients. For the cases that were investigated in this study different prescriptions of the vertical distribution at the lateral model boundaries resulted in only small differences in aerosol distributions within the interior of the model region.