The p-TOMCAT model is a 3D global Eulerian model, driven here by meteorological fields (winds, temperatures and humidities) from the operational analyses of the European Centre for Medium-range Weather Forecasts. For the purposes of this work, it was run at a resolution of ~2.8° x ~2.8° on 31 hybrid sigma-pressure levels. The levels extend from the surface to 10 hPa with a spacing of approximately 100 m in the boundary layer and 1-1.5 km in the vicinity of the tropopause. The model’s chemistry includes 52 species and 174 reactions that together describe the gas-phase HOx/NOx chemistries of methane, ethane, propane and isoprene; isoprene oxidation follows the Mainz Isoprene Mechanism (Pöschl et al., 2000).