Modelling the climate and its evolution at the global and regional scales

Principal Investigator

Prof J. P. van Ypersele and Prof Th. Fichefet
Institut de l'Astronomie te de Geophysique G Lemaitre
Université catholique de Louvain
2 Chemin du Cyclotron
B-1348 Louvain-la-Neuve
Belgium

vanypersele@astr.ucl.ac.be and fichefet@astr.ucl.ac.be

Project description

The main objective of the CLIMOD (CLImate MODelling) network project is to contribute to the international research effort leading to an improved understanding of the climate system and to a better assessment of the impact of human activities on the global and regional climates. Two main tools will serve this objective: modelling and data analysis.

Four among the best Belgian laboratories will pool their expertise in this project: the Global Climate Modelling Group of the Institut d'Astronomie et de Géophysique G. Lemaitre (ASTR), the Regional Climate Modelling Group of ASTR, the Geografisch Instituut of the Vrije Universiteit Brussel, and the General Climatology Section of the Royal Meteorological Institute of Belgium.

Today, members of the CLIMOD network have at their disposal a coupled atmosphere-ocean general circulation model (AOGCM; the first and only one in Belgium), a regional atmospheric model (RegAM), and a Greenland ice-sheet model (GISM). Each of these complex three-dimensional models is run by a different team in a different location. At the end of the project, an advanced "community model", to which each team will have contributed a component will be accessible to all in a common computer environment.

The physics in each component will be improved to stay in line with the latest advances of the climate science. Interactions between turbulence, convection, clouds, and radiation will receive particular attention in the AOGCM, with the specific goal to reduce the drift observed with most similar models. The GISM will be improved in the areas of basal sliding, iceberg calving, and bedrock isostasy. After a thorough validation over Greenland, the RegAM will be used to develop a meltwater-budget parameterization to be imbedded in the coupling interface between the GISM and the AOGCM. A 50-km resolution version of the RegAM will be validated over Western Europe for the present climate. In a finer-resolution version of the RegAM limited to Belgium, one will test physical parameterizations adapted to the simulation of extreme weather events (e.g., storms, fog). To validate these models and put the future regional changes they simulate in perspective, data from two sources will be used: analyses from a numerical weather prediction model, and a new regional database for Belgium produced for this purpose.

The AOGCM and GISM will be coupled using the parameterization derived with the RegAM. The coupled model will then be forced with the IPCC IS92a scenario, and the impact of iceberg discharge and meltwater flow on the sea level and on the oceanic thermohaline circulation will be studied. The results of this coupled run will be analysed, with a particular attention paid to Western Europe and the North Atlantic.

To refine climate projections over Western Europe, the 50-km resolution RegAM will be nested in the coupled model, and time-slice climate change experiments will be performed.

Finally, the transition towards an even more advanced AOGCM will be prepared.

The ECMWF computers will be used for running the LMD atmospheric GCM coupled to the ASTR-UCL coupled ocean/sea-ice model (CLIO), and for running the ASTR-UCL regional atmospheric model (MAR) in order to achieve the CLIMOD objectives. The CLIMOD project involves cooperation between ASTR-UCL (Université catholique de Louvain), the IRM-KMI (Royal Meteorological Institute) and the VUB (Free University of Brussels). ASTR-UCL coordinates the project. The personnel for CLIMOD research is funded by the Belgian Ministry for Science Policy.

Final report.

Additional information

Project started in 1998, finished 2003.