The role of subsurface freeze and thaw on groundwater storage and connectivity in a variably saturated upland Arctic hillslope
Abstract
Upland permafrost regions occupy approximately one third of the Arctic landscape. In these regions, hydrologic fluxes along zero-order geomorphic features known as water tracks, can be promoted or impeded by seasonal freezing. Flow enhancement or impedance depends on multiple factors: field measurements suggest that soil moisture and subsurface flow differences between water tracks and their adjacent hillslopes may strongly influence ground thermal response to varying air temperatures. As continued warming of air temperatures in the Arctic may amplify the depth of seasonal freeze and thaw of the subsurface, it is imperative to examine the relationship between subsurface freeze and thaw and water tracks' variable flow and soil saturation status.
Here, we characterize how the rate and timing of subsurface thaw interacts with subsurface water storage and hillslope connectivity in an upland Arctic hillslope using SutraICE, a coupled subsurface flow and heat transport model with freeze and thaw capabilities for variably saturated media. The model is applied to a representative Arctic hillslope and narrow water track with a drainage area of 0.029 km2 in the Upper Kuparuk River watershed, North Slope, Alaska, USA. We calibrate the model with hydrologic and thermal field data including subsurface temperature, air temperature, precipitation, snow depth, water table depth, and discharge collected in the water track and its adjacent non-water-track hillslope from 2013-2014. Initial results suggest that variable saturation strongly influences summer ground thermal patterns and consequently, subsurface flow paths. The results of this work may inform our understanding of how variably saturated active layers in Arctic uplands influence terrestrial and aquatic thermal and hydrologic responses to warming temperatures.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.C51C1051E
- Keywords:
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- 0702 Permafrost;
- CRYOSPHEREDE: 0710 Periglacial processes;
- CRYOSPHEREDE: 1625 Geomorphology and weathering;
- GLOBAL CHANGEDE: 1807 Climate impacts;
- HYDROLOGY