Bioclimate analogue regions - finding present day examples for future bioclimatic conditions.

This study combines the method of climate analogue regions with a bioclimatic approach. Bioclimate analogue regions were determined for the Rhenish lignite mining area in western Germany, which will face a major structural change in the following decades. These analogue regions currently experience a similar number of days with heat stress compared to the projected future (RCP8.5) at the end of the century in the investigation area. The method is based on the Universal Thermal Climate Index (UTCI) parameters temperature, solar radiation, wind and relative humidity in 3-h temporal resolution while taking day- and night-time values into account. The analogues were calculated for an ensemble of 15 GCM-RCM model combinations from EURO-CORDEX data. The results suggest that analogue regions of the Rhenish lignite mining area are most likely to be found in southern Europe. The highest similarities for the whole ensemble can be found around the Gulf du Lion in southern France. However, some other regions, e.g. around the Black Sea, north of the Balkan Mountains or south of Bordeaux are good fits in some individual model results. While some of these regions are in accordance with previous studies on climate analogue regions, some others were unexpected. The study further shows advantages of using full-coverage instead of punctual data for climate analogue determination, as the results in this study exhibit a high level of spatial detail. For areas facing major structural changes, knowledge of possible climate futures and their present examples can be key aspects for regional planning.