Elevation dependence of biases and trends of climatic indices from EURO-CORDEX regional climate models in the European Alps

Climate change is a global phenomenon with regionally varying peculiarities and sensitivities, such as in the Mediterranean region, which is characterised by observed climatic changes that exceed global means. A significant impact on Mediterranean weather and climate is due to one of its mountain range systems, the European Alps, that are especially sensitive to climatic changes. At the same time, the complex local topography of the Alpine region modulates meteorological and climatic patterns which makes the projection of the evolving mountain environment and climate even more complex. To put estimates of future climate change patterns in the Alpine area, in this study we evaluate the representativeness of historical climate simulations in function of the elevation over the European Alps by using the EURO-CORDEX ensemble of regional climate models at 0.11° resolution. In addition to the raw simulations, we also evaluate the models and bias adjustment methods as available within CORDEX-Adjust. The model data are compared to high-resolution observational datasets over the entire Alpine region, such as APGD and EOBS, and to national observational datasets. Besides climatic averages, also climatic indices that sample extreme conditions are evaluated. We identify potential advantages and weaknesses of bias-adjustment methods depending on elevation, region, and climatic index. Based on the results, we can evaluate which are the most appropriate indices for studies including climate change adaptation, and defining physical mechanisms at play.