Quantifying the Effect of Model Scales with the Inclusion of Groundwater on Simulated Surface-Energy Fluxes

Abstract:

Non-linear interactions between landcover and soil moisture affects the partitioning of surface energy fluxes. On the other hand, spatial-temporal variability of soil moisture is dependent on: 1) Variability of meteorological conditions and precipitation events, and 2) Spatial heterogeneity of landcover, geology and topography. For numerical models, heterogeneity is a deterministic source of variability and a possible pattern generator dependent on the modeling scale (grid cell size) of the numerical domain. Modeling scale becomes important as one moves from column models ( related to modeling vertical fluxes) to physically based models with integrated surface-groundwater flows, adding a new dimension of spatial complexity. This study tries to examine how the model scales effect the soil moisture variability and surface-energy fluxes with the inclusion of lateral surface and groundwater flow. We use the hydrological component of the newly developed Terrestrial System Modeling Platform (TerrSysMP) over a subcatchment of Rur in Germany. The hydrological component of TerrrSysMP (TerrSysMP-Hydro) consists of NCAR Community Land Model (CLM) coupled with 3D variably saturated ground water model ParFlow. Results are presented based on the yearly simulations at multiple modeling scales (960m, 480m, 240m, 120m and 90m).