The project Flood hazard in a changing climate is addressing the issue whether a change of risk for flood events of different severities has to be expected within a changing climate in the near future (2021-2050). The project is funded by the Center for Disaster Management and Risk ReductionTechnology (CEDIM, www.cedim. de).
CEDIM is an interdisciplinary research center in the field of disaster management supported by Helmholtz-Centre Potsdam, German Research Centre for Geosciences and the Karlsruhe Institute of Technology (KIT).
The assessment of changes in flood hazard for small and medium sized river catchments requires spatial and temporal high resolved climate simulations. For the quantification of uncertainty ranges in particular due to different global climate models, regionalization techniques, model type and model setup an ensemble of high resolution regional climate simulations and hydrological simulations (see Figure 1) is developed.
Regional climate simulations with a high spatial resolution of 7 km are carried out with two regional climate models (CCLM at IMK-TRO and WRF at IMK-IFU). Thereby a similar setup for CLM and WRF with respect to domain size, horizontal and vertical resolution is used. Hydrological simulations are carried out for each of the following three catchments with at least two different hydrological models (WaSiM at IMK-IFU). As representative small to medium sized river catchment s for the alpine, low mountain range, and lowland region in Germany the following catchments were defined: Ammer, Ruhr, and Mulde.
• KIT, Institute for Meteorology and Climate Research - Troposphere (IMK-TRO), Karlsruhe
• GFZ, Section 5.4: Hydrology - German Research Centre for Geosciences, Potsdam
• KIT, Institute for Meteorology and Climate Research - Atmospheric Environmental Research (IMK-IFU), Garmisch-Partenkirchen
Figure 1: Schematic over the ensemble simulations strategy. The additional step of bias correction is included on the right side of the diagram
Figure 2: Annual precipitation change [\%] over Germany in 7 km resolution between 1971 to 2000 and 2021 to 2050; top row: CEDIM ensemble mean, ECHAM5 realisation one driven CCLM and WRF simulations; bottom row: CCCma3 driven