VIC-WUR

Within our group we develop and maintain the VIC-WUR global-to-regional scale hydrological model. We can run this model in several settings over various spatial and temporal scales. For example, including groundwater flow, connected to a crop growth model, and connected to a sectoral water demand and water use module. Run for past, current and future conditions. Results are used to assess impacts and trade-offs of global change, assess adaptation options and impacts, and in early warning systems. 

Core model developers are: Lisanne Nauta, Karun Datadien, and Sida Liu. Coordinated by Inge de Graaf

Model description

VIC-WUR 

The Variable Infiltration Capacity (VIC) model (Liang et al., 1994) is a semi-distributed macroscale hydrological model and forms the fundamentals of the VIC-WUR model. The VIC-WUR model is an extension of the VIC-5 model and includes additional modules to account for anthropogenic influences (Hamman et al., 2018, Droppers et al., 2020). In this contract, the model will be setup to simulate natural flow conditions.  

Land Cover 

The surface fluxes and the water and energy fluxes at the land surface are simulated at daily time step for each cell individually; i.e. there is no lateral water or energy exchange. Sub-grid heterogeneity is represented using a statistical distribution of land cover classes. These land cover classes influence soil evaporation and the attenuation of wind and radiation in the interspaces between individual plants. Leaf Area Index (LAI) and albedo values for each land cover class are prescribed from monthly climatology to account for seasonal variability (Bohn and Vivoni, 2016). 

Soil 

The VIC-WUR model uses 3 vertical soil layers with spatially varying depths excluding a fixed 0.3m top-soil layer. The infiltration into the top-moist layers is controlled by variable infiltration capacity. The upper two soil layers interact with the vegetation layer and provide water for transpiration. The third (deepest) soil layer is assumed to be outside the root zone and accounts for subsurface runoff (baseflow) following the Nijssen baseflow formulation (Nijssen et al, 2001). Frozen soil processes are included using the numerical approach of Cherkauer and Lettenmaier (1999). 

Evapotranspiration 

Potential transpiration is computed for the current vegetation, using its current architectural resistance and LAI to compute canopy resistance in the absence of limitation from soil moisture, vapor pressure deficit, temperature, or insolation. The Penman-Monteith formula is used to calculate the potential transpiration with architectural resistance and LAI. 

Snow  

The snow is captured in two components: ground snowpack and canopy-intercepted snow. The ground snowpack is treated as a quasi two-layer system where the uppermost layer is considered separately for solving the energy balance at the pack surface (Andreadis et al., 2009). The snow algorithm also considers partial snow coverage and blowing snow sublimation (Bowling et al, 2004).  

References 

Liang, X., Lettenmaier, D. P., Wood, E. F., & Burges, S. J. (1994). A simple hydrologically based model of land surface water and energy fluxes for general circulation models. Journal of Geophysical Research: Atmospheres, 99(D7), 14415-14428. https://doi.org/10.1029/94jd00483  

Hamman, J. J., Nijssen, B., Bohn, T. J., Gergel, D. R., & Mao, Y. (2018). The Variable Infiltration Capacity model version 5 (VIC-5): infrastructure improvements for new applications and reproducibility. Geosci. Model Dev., 11(8), 3481-3496. https://doi.org/10.5194/gmd-11-3481-2018  

Droppers, B., Franssen, W. H. P., van Vliet, M. T. H., Nijssen, B., & Ludwig, F. (2019). Simulating human impacts on global water resources using VIC-5. Geosci. Model Dev. Discuss., 2019, 1-40. https://doi.org/10.5194/gmd-2019-251  

Cherkauer, K. A., & Lettenmaier, D. P. (1999). Hydrologic effects of frozen soils in the upper Mississippi River basin. Journal of Geophysical Research: Atmospheres, 104(D16), 19599-19610. https://doi.org/https://doi.org/10.1029/1999JD900337  

Bohn, T. J., & Vivoni, E. R. (2016). Process-based characterization of evapotranspiration sources over the North American monsoon region. Water Resources Research, 52(1), 358-384. https://doi.org/https://doi.org/10.1002/2015WR017934  

Nijssen, B., O'Donnell, G. M., Lettenmaier, D. P., Lohmann, D., & Wood, E. F. (2001). Predicting the Discharge of Global Rivers. Journal of Climate, 14(15), 3307-3323. https://doi.org/10.1175/1520-0442(2001)014<3307:Ptdogr>2.0.Co;2  

Andreadis, K. M., Storck, P., & Lettenmaier, D. P. (2009). Modeling snow accumulation and ablation processes in forested environments. Water Resources Research, 45(5). https://doi.org/https://doi.org/10.1029/2008WR007042  

Bowling, L. C., Pomeroy, J. W., & Lettenmaier, D. P. (2004). Parameterization of Blowing-Snow Sublimation in a Macroscale Hydrology Model. Journal of Hydrometeorology, 5(5), 745-762. https://doi.org/https://doi.org/10.1175/1525-7541(2004)005<0745:POBSIA>2.0.CO;2