Effects of Climate Change on Water and Heat Fluxes in the Shallow Subsurface in Cold Regions
Freezing and thawing of water in the shallow subsurface in cold regions plays a significant role in the exchange of water between the land surface (e.g., precipitation, infiltration) and the subsurface (e.g., aquifer recharge). ÌýA warming climate will lead to changes in the timing and duration of freezing events, which will impact near-surface water and heat fluxes. How these changes will affect groundwater temperature and groundwater recharge remains an open question.Ìý
This work develops an Amanzi-ATS model of the Karhinkangas aquifer in central Finland and uses the model to investigate the effects climate warming on groundwater temperature and recharge. Amanzi-ATS is a flexible multi-physics flow and transport simulator with capabilities to simulate coupled surface and subsurface hydrologic and thermal processes, including freeze-thaw capabilities in both surface and subsurface regimes. ÌýThe simulations consider transient changes in pressure, temperature, and water/ice saturation in the shallow subsurface as a result of time-varying air temperature and precipitation signals. The results improve the understanding of subsurface freeze-thaw dynamics and implications on groundwater recharge. Ìý