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Abstract. Ice-free land comprises 26 % of the Earth's surface and holds liquid water that delineates ecosystems, affects global geochemical cycling, and modulates sea levels. However, we currently lack the capacity to simulate and predict these terrestrial water changes across the full range of relevant spatial (watershed to global) and temporal (monthly to millennial) scales. To address this knowledge gap, we present the Water Table Model (WTM), which integrates coupled components to compute dynamic lake and groundwater levels. The groundwater component solves the 2D horizontal groundwater flow equation using non-linear equation solvers from the C++ PETSc (Portable, Extensible Toolkit for Scientific Computation) library. The dynamic lake component makes use of the Fill–Spill–Merge (FSM) algorithm to move surface water into lakes, where it may evaporate or affect groundwater flow. In a proof-of-concept application, we demonstrate the continental-scale capabilities of the WTM by simulating the steady-state climate-driven water table for the present day and the Last Glacial Maximum (LGM; 21 000 calendar years before present) across the North American continent. During the LGM, North America stored an additional 14.98 cm of sea-level equivalent (SLE) in lakes and groundwater compared to the climate-driven present-day scenario. We compare the present-day result to other simulations and real-world data. Open-source code for the WTM is available on GitHub and Zenodo.
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Water table: WTM steady-state water table simulations for LGM and present day
We used the Water Table Model (WTM) to simulate steady-state water tables at the Last Glacial Maximum (LGM, 21,000 calendar years before present), and in the present day. This dataset includes two GeoTIFF files (one for each time simulated). These files represent steady-state water table depth, including both groundwater table and lake surfaces. Water table depth is reported in metres relative to the land surface: negative numbers represent groundwater, and positive numbers represent lakes. The WTM does not include ice hydrology, such that lakes atop ice sheets may not be well represented.
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- Award ID(s):
- 1903606
- PAR ID:
- 10648711
- Publisher / Repository:
- HydroShare
- Date Published:
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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