ReKliEs-De – Regional Climate Projections Ensemble for Germany | Umweltbundesamt

Developed for the fifth report of the Intergovernmental Panel on Climate Change (IPCC AR5), the global initiative CMIP5 (Coupled Model Intercomparison Project Phase 5) represents global climate simulations enabling a new category of climate scenarios. Including the fourth IPCC report, scenarios had been based on emission trends of greenhouse gases so far. The new RCP scenarios (Representative Concentration Pathways) provides scenarios of concentration gradients. Under the European initiative EURO-CORDEX (Coordinated Downscaling experiment for Europe) several of these global simulations have been regionalized using (dynamic) regional climate models.

Within work package 3 of this project, climate projection results gathered so far in previous projects will be pooled (using the SRES scenarios) and prepared for a joint evaluation. Based on this the new climate simulation results (using the RCP scenarios) will be compared with the results obtained so far. There will be a classification of the new results. It will be analyzed whether the new results are in the same range of expected changes like the results obtained so far, or whether they need to be reclassified.

Furthermore, new simulations will be carried out within work package 4. This includes the preparation of regional (statistical and dynamical) climate models for the use of the new input data - from previously used global climate models and the new RCP scenarios - as well as the evaluation of the model results. In addition, complementary high resolution simulations (1x1 km) for several selected heavy precipitation events will be carried out. This particularly high resolution simulations will be used to assess the usability of the lower resolution simulations (12x12 km) especially for hydrological studies on the effects of heavy precipitation events.

On the one hand, work package 5 intends to prepare new high resolution observation data to evaluate the model results. On the other hand, the direct model results will be standardized within this work package to analyze and compare them with one another as well as with further simulation results scientifically.

In work package 6 analyzes will be carried out to assess the range of climate change signals and future extreme events. In addition, it will be investigated whether and if so, which systematic differences of the results are there between statistical and dynamic regional climate models. A robustness analysis will be carried out, which intends to investigate how many ensemble members are needed for stable results and how these members need to be selected. Furthermore, this work package includes the proper representation and visualization of complex ensemble results in a form that is appropriate for the use in climate research and policy advice.

all parameters of the climate models

The project analyzes are used to estimate whether the climate change signals used so far are still adequate for the use of planning and implementation of climate protection and adaptation measures, or whether risks have to be reassessed and adaptation measures designed differently or need to be prioritized. Thus existing user surveys will be evaluated and if necessary further surveys of potential users of the project results be carried out. The aim of these evaluations is to optimize the project results in terms of its usability or applicability for target groups (climate impact research and policy consulting).