Introduction

The CLM-Community is an open international network of scientists, who accepted the CLM-Community agreement in all of its details. Members of the Climate Limited-area Modelling-Community (CLM-Community) are applying and developing the regional climate model COSMO-CLM or CCLM, which is the COSMO model in CLimate Mode. In addition, the CLM-Community is developing ICON-CLM which is the regional ICON-LAM in climate mode.

The first version of the COSMO-CLM (named CLM) was developed by colleagues from HZG, PIK and BTU Cottbus on the basis of the Local Model (LM) version 3.1 (now COSMO model), originally developed by the German Meteorological Service. 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 MOdeling (COSMO).

In 2005 CLM became the regional Community-Model for the German climate research. This model version 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 both CLM and LM developments were unified to get a model version for regional climate modelling (COSMO-CLM) and operational weather forecast  (COSMO). From this time, the idea of a uniform model version for weather and climate became a guiding principle of the model development. 

The unified model version COSMO 5 for weather, climate, and environmental research was released in 2015. An intensive evaluation on a climatological time scale on this version was performed. Since CLM-Community Assembly 2016 the new recommended version of the CLM-Community is the COSMO_5.0_clm6. It comes together with a recommendation for the configurations for the European domain (see figure).

Additional effort is put to further configurations for horizontal model grid widths between 1 and 50 km and other regions of the world.

A comprehensive overview over regional climate modeling (in German) is given in PROMET Volume 99 published in 2017.