Impacts of Microtopographic Snow Redistribution and Lateral Subsurface Processes in an Arctic Polygonal Ecosystem
Lateral subsurface hydrologic and thermal processes were explicitly represented in the E3SM Land Model.
A novel analysis of the impact of snow redistribution and lateral subsurface processes on hydrologic and thermal states at a polygonal tundra site near Utqiagvik (Barrow), Alaska.
The research demonstrates the importance of including accurate surface distribution of snow in models to simulate the temperature of subsurface soil temperature and moisture, both vertically and horizontally, during winter and into the warmer seasons.
Current land surface models, including the Energy Exascale Earth System Model (E3SM) Land Model v1 (ELMv1), are inadequate to capture landscape heterogeneity due to microtopographic features in the Alaskan Arctic costal plan. A team led by Lawrence Berkeley National Laboratory extended the ELM to redistribute incoming snow by accounting for microtopography and incorporated subsurface lateral transport of water and energy. The spatial heterogeneity of snow depth during the winter due to snow redistribution generated surface soil temperature heterogeneity that propagated in depth and time. Excluding lateral subsurface hydrologic and thermal processes led to an overestimation of spatial variability in soil moisture and soil temperature as subsurface liquid pressure and thermal gradients were artificially prevented from spatially dissipating over time. This work also demonstrates an important three-dimensional modeling capability integrated in the global-scale land model ELMv1.
William J. Riley
Lawrence Berkeley National Laboratory
This research was supported by the Office of Biological and Environmental Research, within the U.S. Department of Energy (DOE) Office of Science, of under Contract No. DE-AC02- 05CH11231 as part of the Next-Generation Ecosystem Experiments (NGEE)–Arctic and Energy Exascale Earth System Model (E3SM) programs.
Bisht, G., Riley, W. J., Wainwright, H. M., Dafflon, B., Fengming, Y., and Romanovsky, V. E. “Impacts of microtopographic snow redistribution and lateral subsurface processes on hydrologic and thermal states in an Arctic polygonal ground ecosystem: A case study using ELM-3D v1.0, Geoscientific Model Development 11, 61–76 (2018). [DOI:10.5194/gmd-11-61-2018].