Illustration of the MECO(n) modelling system with three COSMO/MESSy refinements over Europe and Germany. The colours indicate the NOₓ mixing ratios at ground level.
MECO(n) is a numerical, global-regional chemistry-climate model. In MECO(n), the global model EMAC is coupled with n instances of the regional model COSMO/MESSy. The COSMO/MESSy instances can either be coupled to EMAC and/or nested within each other, so that the boundary data is taken from the model instance with the coarser resolution and covering a larger area. This coupling takes place "on-line". This means that the global and regional model instances run simultaneously, similar to different compartments (atmosphere, ocean) in a climate model. The boundary data required for the regional model instances is exchanged at runtime. This enables a particularly high update frequency of the boundary data, which is especially important for chemical species with short lifetimes. Both EMAC and COSMO/MESSy use the same description of the chemical processes and the diagnostics of the MESSy modelling system.
We use the MECO(n) model to support (aircraft) measurement campaigns. This includes ´providing tailor-made forecasts with customised diagnostics for planning research flights, as well as analysing the measurements and placing the results in a scientific context. We also use MECO(n) to analyse the impact of anthropogenic emissions, especially from the transport sector, on air quality under different climate conditions. On a regional scale, MECO(n) is used with spatial grid resolutions between 50 km and approx. 1 km.
