The COSMO model in CLimate Mode (COSMO-CLM or CCLM) is a nonhydrostatic regional climate model developed from the Local Model (LM) of the German Meteorological Service by the CLM-Community. Since 2005 it is the Community-Model of the german climate research. The model has been used for simulations on time scales up to centuries and spatial resolutions between 1 and 50 km.

The LM has been developed by the German Weather Service (DWD) for operational weather forecast. Meanwhile it is used and further developed by several other weather services organized in the COnsortium for Small-scale MOdelling (COSMO).

In this sense the COSMO-CLM model system is a unified model system for Numerical Weather Prediction and Regional Climate Modeling.

Model development

The management of the model system is in close cooperation with the COSMO consortium for the COSMO, int2lm, fieldextra as well as VERSUS software. The folder release plan gives an overview over the model developments which are already implemented into which model version. The folder developments lists planned or ongoing development efforts within the COSMO consortium, the CLM-Community and COSMO-ART.

Scientific Documentation

For the scientific documentation of the model please visit the COSMO model documentation on the COSMO model home page. 

The COSMO-CLM is the climate mode of the COSMO model and the source codes of the individual model components  are identical with the COSMO model sources for each main model version.This documentation covers the documentation of the COSMO model and the pre-processing program INT2LM as well as a User's Guide. It is updated regularly.  However, it is never "up to date" since the documentation takes a lot of time. Recent developments are documented  in COSMO Technical Reports and articles in the COSMO-Newsletters.

There are no additional documentations of the source code modifications for the climate mode yet.

Documentation of the (independed) Model System Components

Direct coupled components

  • TERRA (surface and soil model)
  • FLake (a fresh-water lake model) is a COSMO_4 model component
  • ART (Aerosols and Reactive Trace gases) is a COSMO_5 model component. The routines are available from FZK Karlsruhe, B.Vogel,

Component coupled through a standard coupler OASIS

  • CLM (Community Land Model), is an independent SVAT with dynamical vegetation (it is an alternative to TERRA)
  • Veg3D, is a SVAT (it is an alternative to TERRA)
  • TRIMNP, NEMO, and ROMS are regional ocean models
  • CICE is a sea ice model
  • ECHAM is a global climate model (with OASIS a bi-directional nesting is possible)

Programming Standards of int2lm and COSMO-CLM

The COSMO model is written in FORTRAN 90 based on European standards for writing and documenting exchangeable FORTRAN 90 code. Its details are specified in the “COSMO standards for source code development” (see Terms & conditions for the latest version). 



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