Das Projekt "Klimasimulation mit hoher Aufloesung fuer 10 Jahre" wird vom Umweltbundesamt gefördert und von Max-Planck-Institut für Meteorologie durchgeführt. Objective: To evaluate the improvements of the present climate simulation as the model horizontal resolution increases. General Information: The present generation of general circulation models have a horizontal mesh size of between 600 and 300 km. This project addresses the issue of increased horizontal resolution and its main objective is to quantify the benefits of decreasing the grid size from 300 km to 100 km. It will advance our understanding of systematic errors and thereby lead to improvements in the models used for climate prediction. This study will also contribute to the CLIVAR programme by assessing the ability of high-resolution models to reproduce natural variability. The overall aim is to provide some of the quantitative information required to design the next generation of models that will be used to predict climate evolution due to the greenhouse gas radiative forcing for the assessment scenarios proposed within the IPCC framework. Three European models (the CNRM ARPEGE model, the MPI ECHAM4 model, and the UKMO Unified Model), each having a horizontal resolution of around 100 km, will be used for 10-year simulations of the present climate. This project follows on from the AMIP programme coordinated at the international level but performed with lower resolution models. As was the case for AMIP, boundary conditions will be provided by the observed sea surface temperatures for the period 1979-1988. The output of the 3 models will be organized as a common database, together with the ECMWF reanalysis fields which can be used as a reference. Indeed, two of the models use the same spectral truncation (T106) as the reanalysis. This database will be accessible by all European scientists. The study of the output will be organized, according to the specific knowledge of the participants. On the global scale, the simulated fields will be compared with ECMWF reanalyses, and also with fields obtained from a similar experiment, but with a standard resolution of 300 km. On the regional scale, the simulated fields will be compared by national meteorological services with data from the observation network. The surface fluxes of water, momentum and heat in the model exchange with the ocean will be investigated. The radiative fluxes at the top of the atmosphere, as well as at the surface, will be compared with the appropriate observation databases. The time evolution of the Alpine snow mantle, as estimated from the model circulations will be studied. The behaviour of the models over the ice sheets, their ability to force a limited area model, the simulation of blocking phenomena and of baroclinic waves will also be subjects of investigations. Prime Contractor: Centre National de la Recherche Scientifique, URA 1357, Groupe d Etude de l Atmosphere Meteorologique-Game; Zoulouse; France.