TOMCAT chemical transport model

A still taken from a gif showing Arctic ozone layer loss in 2004/5

TOMCAT/SLIMCAT is a 3D offline chemical transport model (CTM).

It can be used to simulate past and current atmosphere, help to interpret observations and diagnose the extent of problems – such as ozone depletion or tropospheric pollution.

The model uses winds and temperatures from meteorological analyses (e.g. from the Met Office) to specify the atmospheric transport and temperatures, and calculates the chemical species in the troposphere and stratosphere.

Model details

  • Variable resolution. Typical resolutions are 5 x 5 degrees for multiannual runs to up to 1 x 1 degree.
  • Forced by meteorological analyses, usually ECMWF and sometimes UKMO.
  • Options of detailed stratospheric or tropospheric chemistry schemes.
  • Options of detailed aerosol microphysics (GLOMAP) and PSCs (DLAPSE).
  • Chemical data assimilation scheme.
  • Embedded trajectory code.
  • Written in Fortran (f77, f90). Runs on most platforms (including vector machines). Parallelised using OpenMP and MPI.

Campaign model results

Key papers

  • Basic model description: (advection, grid, etc) 
    Chipperfield, M.P., New Version of the TOMCAT/SLIMCAT Off-Line Chemical Transport Model: Intercomparison of Stratospheric Tracer Experiments 
    Q. J. R. Meteorol. Soc., 132, 1179-1203, doi:10.1256/qj.05.51, 2006. 
  • Convection scheme: 
    Stockwell, D.Z., and M.P. Chipperfield, A tropospheric chemical transport model: Development and validation of the model transport schemes. Q. J. R. Meteorol. Soc. , 125, 1747-1783, 1998.
  • Stratospheric chemistry scheme: 
    Chipperfield, M.P., Multiannual Simulations with a Three-Dimensional Chemical Transport Model, 
    J. Geophys. Res., 104, 1781-1805, 1999.
  • Tropospheric chemistry scheme: 
    Arnold, S.R., M.P. Chipperfield, and M.A. Blitz, A three-dimensional model study of the effect of new temperature-dependent quantum yields for acetone photolysis, 
    J. Geophys. Res. , 110 (D22), D22305 doi:10.1029/2005JD005998, 22 November 2005 
  • Chemical data assimilation: 
    Chipperfield, M.P., B.V. Khattatov, and D.J. Lary, Sequential Assimilation of Stratospheric Chemical Observations in a Three-Dimensional Model, 
    J. Geophys. Res., 107(D21), 4585, doi:10.1029/2002JD002110, 2002. 

 Model animations