Subgrid variability may strongly affect hydrological models
Elena Leonarduzzi and colleagues presented a comprehensive numerical analysis to demonstrate the effects of sugrid heterogeneity on hydrological fluxes and slope stability
In coarse resolution hydrological models we often ignore the fact that hydrological processes may vary within the computational grid. In this extensive numerical work conducted in a collabrative study between ETH and the Colorado School of Mines, Elena Leonarduzzi and colleagues quantify the effect of such subgrid heterogeneities in topography and soil thickness. The presence of subgrid side slope is shown to be most important, leading to large underestimation of runoff, affecting the spatial distribution of soil moisture, and overestimating slope stability. This recently published work is raising a warning to modellers who should consider ways to include subgrid effects in coarse-scale hydrological predictions.
Leonarduzzi, E., Maxwell, R. M., Mirus, B. B., & Molnar, P. (2021). external page Numerical analysis of the effect of subgrid variability in a physically based hydrological model on runoff, soil moisture, and slope stability. Water Resources Research, 57, e2020WR027326.