Future evolution of European terrestrial water resources in the groundwater-to-atmosphere regional climate system model TSMP1

The intensification of the water cycle with climate change not only affects hydroclimatic extremes but also water resources, i.e., water availability, with implications for natural and managed systems, including agricultural, industrial and domestic water use. As part of the ongoing Coordinated Regional Downscaling Experiment European initiative (EURO-CORDEX) downscaling CMIP6 GCMs, we contribute with the fully coupled TSMP1 to the EURO-CORDEX regional climate model ensemble. TSMP1 consists of the atmospheric model COSMO, the Community Land Model, and the integrated hydrologic model ParFlow, connected through the OASIS3-MCT coupler. TSMP1 simulates the complete terrestrial water cycle from the groundwater (down to -60m) to the atmosphere. We show initial results from a transient climate run from 1950 to 2100, downscaling the MPI ESM1.2-HR CMIP6 GCM historical and SSP1-2.6 and SSP3-7.0 scenarios over the 12km pan-European CORDEX domain (EUR-12). Simulations are aligned with the CORDEX-CMIP6 simulation protocol and further extend the balanced GCM-RCM matrix. We investigate the future evolution of essential variables related to the terrestrial water cycle, such as the total water storage, groundwater recharge, and water table depth for 30-year mid- and end-of-the-century time slices over PRUDENCE regions. Past hydroclimatic extremes, decadal variability, and future trends are well reflected in the TSMP1 groundwater to top-of-atmosphere representation, which provides physically consistent 4D images of the coupled terrestrial water and energy cycles.