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The Impact of Representing Variable Soil Thickness with Topographic Subgrid Heterogeneity in E3SM

Presentation Date
Monday, January 11, 2021 at 1:40pm



The simulation of soil moisture, surface runoff, and groundwater processes have been shown to be affected by the inclusion of variable soil thickness using a realistic estimate of depth-to-bedrock rather than a constant soil thickness coupled to a groundwater model. Testing of this has so far largely been performed using grid cell mean soil thickness, but, since depth-to-bedrock (DTB) is strongly determined by topographic setting, there would be a large variation in DTB in regions of highly variable topography. Recently, a subgrid structure to represent topographic subgrid heterogeneity has been included in the Energy Exascale Earth System Model (E3SM) Land Model (ELM) on which DTB will be supplied by our dataset for simulations with variable soil thickness. In addition, grid cell mean meteorological forcings will be downscaled to the various topographic units representing the subgrid structure. The change in hydrological fluxes like surface runoff and evapotranspiration and in sub-surface temperature from the representation of grid cell mean soil thickness to the representation on topographic units will be explored. The impact of feedbacks between land and atmosphere will be further evaluated by comparing land-only simulations with atmosphere-land coupled simulations.

Funding Program Area(s)