Air Quality Simulations Over Europe for the Period 1996–2006 with Emphasis on Tropospheric Ozone

A modeling system based on the air quality model CAMx driven off-line by the regional climate model RegCM3 is used for assessing the impact of lateral boundary conditions and anthropogenic emissions on tropospheric ozone over Europe for the period 1996–2006. The RegCM3 and CAMx simulations were performed on a 50 km × 50 km grid over Europe with RegCM3 driven by NCEP reanalysis fields. Average monthly concentration values obtained from the global chemistry climate model ECHAM5-MOZ were used as chemical boundary conditions for the CAMx simulations. The present period (1996–2006) was simulated four times. The first run was forced with time and space invariable lateral chemical boundary conditions and EMEP emissions based on the year 1996. The second decadal simulation was based on ECHAM5-MOZ chemical boundary conditions and emissions both fixed for the year 1996. The third decadal simulation was based on ECHAM5-MOZ chemical boundary conditions with interannual variation but fixed emissions from the year 1996. Finally, the fourth decadal simulation was based on ECHAM5-MOZ chemical boundary conditions and emissions, both having interannual variation. Simulated ozone concentrations are compared against measurements from the EMEP network in order to evaluate the modeling system.