Friedrich Boeing

and 10 more

Global warming is altering soil moisture (SM) droughts in Europe with a strong drying trend projected in the Mediterranean and wetting trends projected in Scandinavia. Central Europe, including Germany, lies in a transitional zone showing weaker and diverging change signals exposing the region to uncertainties. To analyse the projected SM drought changes and associated uncertainties in Germany, we utilize a large multi-model ensemble of 57 bias-adjusted and spatially disaggregated regional climate model simulations to run the hydrologic model mHM at a high spatial resolution (0.015625°, eq. 1.2 km) for Germany over the period 1971-2098. We show that projections of future changes in soil moisture droughts over Germany depend on the emission scenario, the soil depth and the timing during the vegetation growing period. The most robust and widespread increase in soil moisture drought intensities is projected for upper soil layers (0-30 cm) in the late growing season July-September under RCP8.5. There are greater uncertainties in the changes in soil moisture droughts in the early vegetation growing period (April-June). Regional differences are visible, with the strongest Soil moisture Drought Intensities (SDI) increase in the south-west of Germany. In the north-east, we observe divergent trends between the top soils and the total soils (0-200 cm). We find stronger imprints of changes in meteorological drivers controlling the spatial disparities of SM droughts than regional diversity in physio-geographic landscape properties. Our study provides nuanced insights for an important climatic transition zone and is therefore relevant for regions with similar transitions.