Vorticity at 850 hPa after 9 days of simulation of the Jablonowski Williamson baroclinic wave test; comparison of ECHAM at resolution T255 (left) and the ICON hydrostatic dynamical core using a triangular grid at resolution R2B06 (right).

ICON

The ICON dynamical core is a new development initiated by the Max Planck Institute for Meteorology (MPI-M) and the Deutscher Wetterdienst (DWD). This dynamical core will combine several properties, which are considered important for future progress in numerical weather forecasting at DWD or climate research at MPI-M.

In particular the ICON dynamical core will solve the fully compressible non-hydrostatic equations of motion for simulations at very high horizontal resolution. The discretization of the continuity and tracer transport equations will be consistent so that mass of air and its constituents are conserved, which is a requirement for atmospheric chemistry. Furthermore, the vector invariant form of the momentum equation will be used, and thus, vorticity dynamics will be emphasized.

The new dynamical core solves the system of equation in grid point space on the icosahedral grid, which allows

  • the quasi-isotropic horizontal resolution on the sphere, and

  • the restriction to regional domains.

The choice of triangular cells given by the Delaunay triangulation allows C-grid type discretization and straightforward local refinement in selected areas, in the global as well as regional framework.

Alternative grid options for ICON are also intended: These comprise the hexagonal C-grid as an alternative to the triangular version, and a quadrilateral regional version for simplified comparison with existing limited area models.

 

Models

 

  The following models have reached a mature stage:

  • a shallow water model,
  • a hydrostatic atmospheric dynamical core, with or without local grid refinement,
  • a non-hydrostatic atmospheric dynamical core, with or without local grid refinement, and
  • flux-form semi-Lagrangian schemes for tracer transport.

 We are currently working on

  • the hydrostatic atmospheric model ICOHAM, which uses the ECHAM physics parameterization, and will be used in climate research;
  • the non-hydrostatic atmospheric model ICONAM, which will be used for operational weather forecast at DWD;
  • the hydrostatic ocean model ICOHOM;
  • a coupled atmosphere ocean ICON model.