The project “Updating the data basis for adaptation to climate change in Germany” (UDAG) provides high-resolution regional climate projections generated with the ICON-CLM regional climate model as part of the CORDEX-CMIP6 (https://cordex.org/experiment-guidelines/cordex-cmip6/) initiative.
Global climate models (GCMs) provide the basis for climate projections under different climate scenarios. However, with typical horizontal resolutions of 80–100 km, GCMs cannot adequately represent regional and local climate features relevant for climate impact assessments and adaptation planning. Dynamical downscaling uses GCM projections as boundary conditions for high-resolution regional climate models (RCMs), enabling finer-scale simulation of climate processes. In UDAG, the regional climate model ICON-CLM downscales global projections to ~12 km across Europe and, for a selected subset, to ~3 km over Central Europe. This higher resolution improves the representation of complex terrain, land-surface heterogeneity, and local weather processes, providing a scientific basis for regional climate change adaptation.
UDAG provides historical RCM simulations and climate projections for the EUR-12 domain of EURO-CORDEX, dynamically downscaled from six CMIP6 GCMs (MPI-ESM1-2-HR, EC-Earth3-Veg, MIROC6, CNRM-ESM2-1, CMCC-CM2-SR5, and NorESM2-MM) under SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5. A quality-checked subset of the 12 km simulations is further downscaled for SSP1-2.6 and SSP3-7.0 to 3 km over Central Europe (CEUX-3) using ICON-CLM in a convection-permitting setup. Simulations are performed by DWD, KIT, Hereon, GERICS, BTU, C2SM, FZJ, Wegener Centre, and IMWM. Both ICON-CLM setups were optimized in the COPAT2 (EUR-12) and CECPI-Ger (CEUX-3) initiatives of the CLM community through objective tuning of numerous model parameters (Geyer et al, 2026, https://doi.org/10.5194/egusphere-2025-4726).