Snow and Frozen Ground Simulations

Snow Model of Helmand River Basin, Afghanistan

  • Follum, M. et al. (2019). “A comparison of snowmelt‐derived streamflow from temperature‐index and modified‐temperature‐index snow models”. Hydrological Processes. 1– 16.
  • Follum, M. et al. (2018). “A simple temperature-based method to estimate heterogeneous frozen ground within a distributed watershed model”. Hydrol. Earth Syst. Sci.,
  • Follum, M. and C. Downer (2013). “Snow Water Equivalent Modeling Capabilities of the GSSHA Watershed Model”. Coastal and Hydraulics Laboratory Technical Report ERDC/CHL TR-13-4. U.S. Army Engineer Research

Snow Model of Helmand River Basin, Afghanistan

Water from the snowpack drives the rivers for much of the World and can be a large contributor to flooding. Historically, snow has been difficult to simulate due to limited data availability for both forcing and calibrating the numerical methods. Many hydrologic models contain multiple snow simulation methods depending on available data. Complex methods solve the physical processes within the snowpack, but often require numerous and highly-accurate forcing data. Simpler methods require less data, but often miss the spatial characteristics of the snowpack (differences between South- and North-facing slopes, shading, vegetation, etc.). Dr. Follum developed the Radiation-Derived Temperature Index (RTI) snow method and the Modified Continuous Frozen Ground Index (ModCFGI) method to help simulate snowpack and frozen ground more accurately using minimal data. Both methods have been implemented within the U.S. Army Gridded Surface Subsurface Hydrologic Analysis (GSSHA) model. The RTI snow method is an option within the HEC-HMS model.

Frost Depth simulations for Sleepers River Experimental Watershed, VT.

CFGI: Spatial variation based on elevation
modCFGI: Spatial variation based on land cover, elevation, and slope/aspect.