ICON (Icosahedral non-hydrostatic) general circulation model

The ICON dynamical core is a development initiated by the Max Planck Institute for Meteorology (MPI-M) and the Opens external link in current windowGermany Weather Service (DWD). This dynamical core  is designed to better tap the potential of new generations of high performance computing, to better represent fluid conservation properties that are increasingly important for modelling the Earth system, to provide a more consistent basis for coupling the atmosphere and ocean and for representing subgrid-scale heterogeneity over land, and to allow regionalization and limited area implementations.

In particular the ICON dynamical core will solve the fully compressible non-hydrostatic equations of motion for simulations at very high horizontal resolution.  This approach minimizes global communication, thereby localizing memory access which is advantageous for highly distributed and heterogeneous computing infrastructures.  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 facilitaes

  • 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, and facilitates coupling to the ocean and land.

Currently ICON is undergoing tests in its NWP mode, and the ECHAM physics is being coupled to the dynamical core for the purpose of climate studies.  Tests with a mimetic discretization of the ocean component of the ICON model, designed to eventually replace MIPOM are also under way.  A cloud resolving, or large-eddy simulation version of the ICON core is also intended to replace the current generation of LES models used within the institute, and serve as the basis for a new initiative centered around the high-definition simulations of clouds and precipitation for climate prediction (HD(CP)2).


For more information about ICON at the MPI-M contact Marco Giorgetta (Opens window for sending emailmail) or Peter Korn (Opens window for sending emailmail).