Introduction

Members of the ClimateLimited-areaModelling-Community (CLM-Community) are applying and developing the COSMO-CLM or CCLM, which is the COSMO model in CLimate Mode. The CLM-Community is an open international network of scientists, who accepted the CLM Community agreement in all of its details.

The COSMO model is the nonhydrostatic operational weather prediction model applied and further developed by the national weather services joined in the COnsortium for SMall scale MOdelling (COSMO).

The first version of the COSMO-CLM (named CLM) was developed by colleagues from GKSS, PIK and BTU Cottbus on the basis of the Local Model (LM) version 3.1 (now COSMO model), originally developed by the German Weather Service. In 2005 the CLM became the regional Community-Model for the german climate research. The model has been applied on time scales up to centuries and spatial resolutions between 10 and 50 km in different regions of the world.
In 2007/08 the CLM and the LM developments have been unified and a model version for regional climate modelling COSMO-CLM and operational weather forecast the COSMO, has been made available. The idea of a uniform model version for weather and climate became a guiding theme of the further model development.

The current official model version of the CLM-Community is the COSMO-CLM_3. The COSMO-CLM4 is still being evaluated and tested on space scales between 1 and 50 km and in different regions of the world.