TY - SER ID - hemmerle2020mowa T1 - Metadata of 32 wells and temperature-depth profiles of the shallow subsurface between 1992 and 2019 in Bavaria, Germany AU - Hemmerle, Hannes PY - 2020/10/02/ PB - PANGAEA DO - 10.1594/PANGAEA.923529 UR - https://doi.org/10.1594/PANGAEA.923529 N2 - Thermodynamic coupling between atmosphere and ground yields increasing aquifer temperatures as a consequence of global warming. While this is expected to manifest as a gradual warming in groundwater temperature time series, such continuous long-term recordings are scarce. As an alternative, the present work examines the use of repeated temperature-depth profiles of 32 wells in southern Germany, that were logged during campaigns in the early 1990s and in 2019. It is revealed that the temperatures have increased in nearly all cases. We find a moderate to good depth-dependent correlation to trends in air temperature, which however is strongly influenced by local hydrogeological and climate conditions. While during the last three decades, air temperatures have increased by a rate of 0.35 K (10a)-1 on average, the temperature increase in the subsurface is decreasing with depth, with median values of 0.28 K (10a)-1 in 20 m and only of 0.09 K (10a)-1 in 60 m depth. Still, the slow and damped warming of the groundwater bodies are remarkable, especially considering naturally very minor temperature changes in pristine groundwater bodies and predictions of atmospheric temperatures. This entails implications for temperature-dependent ecological and hydro-chemical processes, and also for the heat stored in the shallow ground. Moreover, it is demonstrated that the annual heat gain in the groundwater bodies below 15 m due to climate change is in the range of one third of the state's heat demand, which underlines the geothermal potential associated with the change in natural heat fluxes at the ground surface. KW - Climate change KW - groundwater temperature KW - shallow geothermal KW - subsurface KW - water resources ER -