General Description: General Description of the COSMO-Model

Last updated: August 2011


The COSMO-Model is a nonhydrostatic 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 NWP-mode, climate mode or for case studies. A comprehensive documentation of all components of the system is provided, the Description of the Nonhydrostatic Regional COSMO-Model. It also informs the user about code access and how to install, compile, configure and run the model.

The basic version of the COSMO-Model (formerly known as Lokal Modell (LM)) has been developed at the Deutscher Wetterdienst (DWD). The COSMO-Model and the triangular mesh global gridpoint model GME form – together with the corresponding data assimilation schemes – the NWP-system at DWD, which is run operationally since end of 1999. The subsequent developments related to the model have been organized within COSMO, the Consortium for Small-Scale Modelling. COSMO aims at the improvement, maintenance and operational application of the non-hydrostatic limited-area modelling system, which is now consequently called the COSMO-Model.