The two-way nested global chemistry-transport zoom model TM5: algorithm and applications M. Krol1, S. Houweling2, B. Bregman3, M. van den Broek2,3, A. Segers3, P. van Velthoven3, W. Peters4, F. Dentener5, and P. Bergamaschi5 1Institute for Marine and Atmospheric Research Utrecht, The Netherlands 2Space Research Organisation Netherlands, Utrecht, The Netherlands 3Royal Netherlands Meteorological Institute, de Bilt, The Netherlands 4National Oceanic and Atmospheric Administration, Climate Monitoring and Diagnostics Laboratory, Boulder, USA 5Joint Research Centre, Institute for Environment and Sustainability, Ispra, Italy
Abstract. This paper describes the global chemistry Transport Model, version 5 (TM5) which allows two-way nested zooming.
The model is used for global studies which require high resolution regionally but can work on a coarser resolution
The zoom algorithm introduces refinement in both space and time in some predefined regions. Boundary conditions of the
zoom region are provided by a coarser parent grid and the results of the zoom area are communicated back to the parent.
A case study using 222Rn measurements that were taken during the MINOS campaign reveals the advantages of
As a next step, it is investigated to what extent simulated concentrations over Europe
are influenced by using an additional zoom domain over North America.
An artificial ozone-like tracer is introduced with a lifetime of twenty days and simplified non-linear chemistry.
The concentration differences at Mace Head (Ireland) are generally smaller than 10%, much smaller than the
effects of the resolution enhancement over Europe. Thus, coarsening of resolution at some distance of a sampling station seems
allowed. However, it is also noted that the budgets
of the tracers change considerably due to resolution dependencies of, for instance, vertical transport.
Due to the two-way nested algorithm, TM5 offers a consistent
tool to study the effects of grid refinement on global atmospheric chemistry issues
like intercontinental transport of air pollution.
Citation: Krol, M., Houweling, S., Bregman, B., van den Broek, M., Segers, A., van Velthoven, P., Peters, W., Dentener, F., and Bergamaschi, P.: The two-way nested global chemistry-transport zoom model TM5: algorithm and applications, Atmos. Chem. Phys., 5, 417-432, doi:10.5194/acp-5-417-2005, 2005.