History of the CLM-Community

In the early 1990s, the Deutscher Wetterdienst (German Meteorological Service, DWD) recognized that future demands on weather forecasting require simulations at convection resolving resolution. As a consequence, grid mesh sizes of much less than ten kilometers were necessary, which could not be achieved by the Deutschlandmodell (DM), the operational model at DWD at that time. The DM was a hydrostatic model and thus limited by physical reasons to grid mesh sizes larger than ten kilometers. Therefore, DWD decided to develop a new non-hydrostatic model, the Lokalmodell (LM).

1999: The LM (LM1.1) replaced the DM as the operational weather forecast model at DWD in 1999 and after several improvements met the expectations in many respects.

The same arguments seemed to be valid for climate simulations. Furthermore, most regional climate models (RCMs) originated from weather forecast models. Therefore, it was not surprising that scientists at the Potsdam Institute for Climate Impact Research (PIK) took into account the LM as an option when they looked for an appropriate Regional Climate Model (RCM) for their WAVES project (Böhm et al., 2003) at the end of the 1990s. The non-hydrostatic kernel, the modern, clear, and modular programming, and the efficient MPI parallelization were some of the reasons to consider LM. After test simulations with encouraging results, scientists at PIK decided to develop a new RCM based on the LM.

In the early 2000s, scientists from BTU Cottbus and GKSS Research Centre (now Hereon) joined the CLM development and formed the basis for the further development of the CLM over the next few years.

2002: In the summer of 2002, the first climate version of the LM (CLM) was completed (LM 2.16 == CLM 1). Colleagues from GKSS Research Centre, PIK, and BTU Cottbus contributed to the development of the first version of COSMO-CLM based on the Lokalmodell (now COSMO model).

2004: Release of the second version of CLM (LM 2.19 == LM 3.1 == CLM 2)

2004: The history of the CLM-Community started in autumn 2004, when colleagues from PIK, GKSS, and BTU Cottbus presented the new version of the Climate Local Model (CLM) and invited all scientists to build a network for systematic development of the CLM, to coordinate the activities and to use the computational resources effectively. The CLM-Community was born.

2004: The first long-term hind-casting simulations (fifteen years driven by ERA15 reanalysis data) were also performed in 2004. The third version of these data sets was used in an intensive validation of the CLM with a focus on the ability of the model to serve as an RCM in comparison with other RCMs. Scientists at BTU Cottbus carried out the major part of this validation and found the CLM to be in the same range of accuracy as other RCMs resolving similar scales. In the same year, the CLM was successfully used for climate projections in the PRUDENCE project (Christensen et al., 2007 ). In the time slice experiments (1961–1990, 2071–2100), the CLM showed again competitive results.

In 2005, the CLM was officially nominated as the community model of the German climate research community by the steering committee of the German Climate Research Centre (DKRZ).

In summer 2005, Andreas Will became the first coordinator of the CLM-Community.

20050930: Decision that COSMO and CLM should be unified regularly and the unified versions get version number X.0 (e.g. 4.0, 5.0,…) was taken.

2006: Release of the third version CLM (unification of LM 3.x and CLM 2.4.11 == CLM 3)

2006: The 1st CLM-Community Assembly took place in Langen, Germany.

In 2006 and 2007, the CLM-Community performed transient climate change runs (consortial runs) for the period 1960-2100 for two GHG scenarios (A1B and B1). Two realizations were produced for each scenario with boundary conditions from ECHAM5. An important milestone at the time.

2007: Release of COSMO 4.0 == CCLM 4. The CLM-Community always kept in touch with the LM developers at DWD. In 2007, this resulted in the reunion of the CLM and the LM (which was renamed to COSMO model in the meantime) into the unified limited area model for operational weather forecast and regional climate modelling COSMO 4.0.

200801: Decision about naming conventions:

  • Model: COSMO-CLM or CCLM (COSMO model in CLimate Mode)

  • Community: Climate Limited-area Modelling Community (CLM-Community)

200806: The community had 70 members from 21 institutions.

200808: The Special Issue “Regional climate modelling with COSMO-CLM (CCLM)” was published in Vol. 17, No. 4 of Meteorologische Zeitschrift.

2009 - present: Active participation of various modelling groups of the CLM-Community in past and ongoing phases of CORDEX for many different regions of the world

200912: The CLM-Community had 125 members from 36 institutions.

20100113: First meeting of the Scientific Advisory Board (SAB) at Berlin-Brandenburgischen Akademie der Wissenschaften (BBAW) in Berlin

20100827: First discussion between BTU Cottbus and DWD about the inclusion of DWD in organizational and administrative tasks of the CLM-Community.

20100831: Startup meeting of the working group AIO with the aim to expand the COSMO-CLM by a regional ocean model.

2011: COSMO-CLM model coupled to the Community Land Model

201202: SAB chair and CLM-Community Coordinator contact the leader of the Climate and Environment division (KU) at DWD, Paul Becker, and offer a meeting to discuss the opportunities of institutionalization of CLM-Community coordination at DWD.

201304: COSMO_4.8_clm17 became the official model version of the CLM-Community together with the recommended configurations for Europe.

20130801: Barbara Früh (DWD) took over the coordination of the CLM-Community from Andreas Will (BTU).

201308: Publication of first CLM-Community newsletter (since then a newsletter has been published every six months).

2014: Release of the unified model version COSMO 5.0 for weather, climate, aerosol, and chemistry (COSMO 5.0 == CCLM 5)

2014: coupled atmosphere-ocean-ice system COSMO-CLM/NEMO (Pham et al. 2014 )

201409: The project group ICON was established to coordinate ICON-CLM development

201509: The 10th CLM-Community Assembly took place in Belvaux, Luxemburg.

20151001: CLM-Community members vote on the new recommended COSMO-CLM during the community meeting at the Assembly in Luxembourg and COSMO5.0_clm6 became the new recommended version of the CLM-Community.

2015: The CLM-Community has 250 members from 70 institutions.

201605: Publication of Special Issue “Recent developments in Regional Climate Modelling with COSMO-CLM, Part 1” in Vol. 25, No. 2 of Meteorologische Zeitschrift

20190917: Christian Steger (DWD) took over the coordination from Barbara Früh (DWD)

201911: After a membership survey, the number of active members in the CLM-Community is adjusted to 198 members from 69 institutions.

20200914: The CLM-Community Assembly is organized as a virtual conference for the first time because of the COVID-19 pandemic.

202101: The CLM-Community signs a development partnership agreement for ICON with DWD and becomes the key development partner of DWD for the further development of ICON in the field of regional climate modelling. 

20210218: The first paper about ICON-CLM is published in Geoscientifc Model Development: Van Pham, T., C. Steger, B. Rockel, K. Keuler, I. Kirchner, M. Mertens, D. Rieger, G. Zängl, B. Früh (2021): ICON in Climate Limited-area Mode (ICON release version 2.6.1): a new regional climate model. Geosci . Model Dev., 14, 985–1005, 2021 https://doi.org/10.5194/gmd-14-985-2021

20210423: A new administration and membership management tool are introduced. The tool replaces the existing pages of our website (institutions, members, and topic browser) and allows the self-management of personal data and information.

20210924: The community members agree on a new strategy for the CLM-Community for the period 2021 - 2026 in the community meeting at Assembly 2021. 

20211215: Release of COSMO 6.0, the last version of the COSMO model. With this release, the development of the COSMO model ended after more than two decades. 

20220923: A new working group “Model Development” is established during the CLM-Community Assembly 2022. The new WG is a platform for information exchange and coordination of the ICON-CLM development.

20230922: The first in-person CLM Assembly after COVID-19 was organized by KU Leuven in Belgium. During the communtiy meeting, the members voted for CMCC as new core consitution of the CLM Community and for COSMO 6.0 with the configuration C2C316 as new recommended version and configuration of the COSMO model. 

20240131: The first ICON Open Source Release was published. ICON is now available to the community under a permissive open source licence (BSD-3C). A new webpage for the ICON model was created and went online together with the open source release (www.icon-model.org )