Using the Community Land Model to Assess Uncertainty in Basin Scale GRACE-Based Groundwater Estimates

Abstract:

One method for interpreting the variability in total water storage
observed by GRACE is to partition the integrated GRACE measurement
into its component storage reservoirs based on information provided
by hydrological models. Such models, often designed to be used in
couple Earth System models, simulate the stocks and fluxes of moisture
through the land surface and subsurface. One application of this
method attempts to isolate groundwater changes by removing modeled
surface water, snow, and soil moisture changes from GRACE total water
storage estimates. Human impacts on groundwater variability can
be estimated by further removing model estimates of climate-driven
groundwater changes. Errors in modeled water storage components
directly affect the residual groundwater estimates. Here we examine
the influence of model structure and process representation on
soil moisture and groundwater uncertainty using the Community Land
Model, with a particular focus on basins in the western U.S.