This dataset contains monthly mean ozone output between 1979-2016 simulated by the TOMCAT/SLIMCAT global three-dimensional chemical transport model.

The data contains ozone and a passive odd-oxygen tracer that is set equal to the modelled chemical Ox =O(3 P)+O(1 D)+ O3 concentration on the first day every year and then advected passively without chemistry. It was simulated using the TOMCAT/SLIMCAT three-dimensional offline chemical transport model, using σ-p vertical coordinates and identical stratospheric chemistry and aerosol loading, solar flux input and surface mixing ratios of long-lived source gases.

The long-term simulation (1979-2016) was performed with a T42 horizontal resolution of approximately 2.8° latitude × 2.8° longitude and 32 levels (hybrid σ-p vertical coordinate) from the surface to 60 km. The model uses horizontal winds and temperature from the reanalysis data of the European Centre for Medium-Range Weather Forecasts.

The TOMCAT/SLIMCAT model contains a detailed description of the distribution of chemical species for the troposphere and stratosphere including heterogeneous reactions on sulfate aerosols and liquid/solid polar stratospheric clouds either with a simple or full microphysical PSC scheme, as well as chemistry reactions of the oxygen, nitrogen, hydrogen, chlorine and bromine families. The model used here has a hybrid σ-p vertical coordinate and has an option to run at different horizontal resolution forced by different meteorological reanalysis. Tracer transport uses the conservation of the second order moments scheme of Prather. Vertical advection is calculated from the divergence of the horizontal mass flux.