TM5

The TM5 model is a 3D atmospheric chemistry-transport ZOOM model. It allows the definition of arbitrary zoom regions, which are 2-way nested into the global model. Thus simulations at relatively high spatial resolution (currently 1x1 degrees longitude-latitude) can be performed over selected regions, with boundary conditions always provided consistently from the global model. 

In order to smooth the transition from the global grid (6x4) to the fine grid (1x1), usually an intermediate zoom region with 3x2 is also employed. The figure to the right shows an example with the zoom regions defined over Europe and Northern Africa. Zooming is possible over any region of interest.

The definition of vertical layers is linked to the 60 vertical layers of the ECMWF model (ERA-interim or OD before 2006). The tropospheric TM5 version uses a subset of 25 layers (mostly in the troposphere). Since January 2006, the operational ECMWF model uses 91 vertical layers, and a 34-layer subset has been created for TM5.