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The SimLab TerrSys is currently primarily involved in supporting groups of the Geoverbund ABC/J and of the TR32 research effort.

Work encompasses the porting, (performance) testing and (standard) setup of the ParFlow.CLM model and the fully coupled TerrSysMP system for different model domains either regionally (North Rhine Westphalia) or locally (small and meso-scale river catchments) at high resolutions at the sub-km grid scale (both model systems) and at a km scale for continent-wide model domains (ParFlow.CLM). In the latter setup, domains may be as large as 10.5 Mio. grid elements and 6 or more depth layers.

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The target architecture at the moment is therefore JUQUEEN, where e.g. ParFlow.CLM scales well with a good efficiency up to a full JUQUEEN rack (16384 tasks) and beyond, but the JUROPA supercomputer is used as well e.g. for smaller problem sizes.

The fully coupled system is likewise trageting at highly scalable architectures, especially when also the atmospheric model component is run at convection resolving resolutions of 3 km and less with very short timesteps. The external coupler OASIS3 is used in order to ensure a higher modularity, more easy upgrades or replacements of model system components and also to promote a more rapid development cycle with relatively few code adjustments. However this MPMD design feature and its fairly complex distribution of tasks needs a lot of scalability testing to determine an optimum run configuration.

When the above configurations are run beyond test cases, validation ore process case studies for longer, transient timespans, e.g. in climate change setups, long runtimes become as well an issue as data handling, processing and storage.

Linked to this are research activities of the SimLab that focus on running the WRF atmospheric model in a climate mode setup in the framework of the Euro-CORDEX initiative as part of the World Climate Research Programme.

A competence centre of