The ICON Modelis a non hydrostatic atmospheric prediction model developed by the german weather service. It has been designed for both operational numerical weather prediction (NWP) and various scientific applications. The ICON Model is based on the primitive thermo-hydrodynamical equations describing compressible flow in a moist atmosphere. The model equations are integrated on an icosahedral grid and a hybrid terrain following height coordinate. A variety of physical processes are taken into account by parameterization schemes. Besides the forecast model itself, a number of additional components such as data assimilation, interpolation of boundary conditions from a driving model, and postprocessing utilities are required to run the model in NWPmode, climate mode or for case studies.
Regional numerical weather prediction at CNMCA is entirely based on the ICON Model. The convection-resolving model ICON-IT, covers Italy and its surroundings with a grid spacing of 2.2 km, on an ichosaedral grid, and interpolated on a 971x771 grid points/layer, and 65 vertical layers. A convection-permitting ensemble prediction system (ICON-IT EPS) is running since March 2025. The ICON model is integrated 20 times on the same domain of the ICON-IT deterministic system, with a grid spacing of 2.2 km, on an ichosaedral grid, and interpolated on a 971x771 grid points/layer, and 65 vertical layers. The initial conditions are from the high-resolution LETKF analysis system and the lateral boundaries conditions are derived from the IFS ECMWF-EPS. It performs 48 h forecasts for the 00 and 12 UTC runs.
