Model Characteristics

The COSMO Model ( a non hydrostatic limited-area atmospheric prediction model. It has been designed for both operational numerical weather prediction (NWP) and various scientific applications on the meso-β and meso-γ scale.

The COSMO Model is based on the primitive thermo-hydrodynamical equations describing compressible flow in a moist atmosphere. The model equations are formulated in rotated geographical coordinates and a generalized 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 COMET is entirely based on the COSMO Model. COSMO-ME covers Europe with 1083x559 grid points/layer at a grid spacing of 5 km and 45 layers, and the convection-resolving model COSMO-IT, covers Italy and its surroundings with a grid spacing of 2.8 km, 542x604 grid points/layer and 65 layers. Based on COSMO-ME, a probabilistic ensemble prediction system on the convective scale, called COSMO-ME-EPS, is operational with 20 EPS members, with a grid spacing of 7 km, 779x401 grid points/layer and 45 layers. It is initialized by the LETKF analysis members and driven by the ECMWF-EPS. A convection permitting ensemble prediction system (COSMO-IT EPS) is running since december 2018 on hybrid CPU/GPU architecture at COMET. The COSMO model is integrated 20 times on the same domain of the COSMO-IT system with a grid spacing of 2.2 km, 576x701 grid points/layer and 65 layers. The initial conditions are from the high resolution LETKF analysis system and the lateral boundaries conditions are derived from the ECMWF-EPS. It performs 48 h forecasts for the 00 and 12 UTC runs.

Documentation is fully available at