HR: 11:35h
AN: H21G-06    [PDF]
TI: Uncertainties Associated With Base Flow Parameterizations in The Variable Infiltration Capacity Land Surface Model in Ungauged Basins Under Cold Climate
AU: * Huang, M
EM: huangmy@uclink.berkeley.edu
AF: University of California, Berkeley, Department of Civil and Environmental Engineering, Berkeley, CA 94720 United States
AU: Liang, X
EM: liang@ce.berkeley.edu
AF: University of California, Berkeley, Department of Civil and Environmental Engineering, Berkeley, CA 94720 United States
AB: Identifying dominant physical processes and estimating the model parameters associated with these processes through a physically based approach is critical for improving hydrologic simulations and predictions with reduced uncertainties for given regions. For ungauged basins, this is probably even more important because often the hydrological model predictions suffer significantly more uncertainties. In this study, we focus on investigating the subsurface flow process and evaluate its associated model parameter estimations for cold regions through water and energy budget simulations by applying a new version of the Three-Layer Variable Infiltration Capacity (VIC-3L) land surface model, called VIC-ground, which incorporates dynamically the surface and groundwater interactions. In VIC-ground, groundwater table depth can be dynamically simulated and thus could greatly facilitate the investigation of an alternative base flow parameterization based on Boussineq equation for unconfined flow in a sloping aquifer. This base flow parameterization has more physical basis and its associated model parameters can be related with watershed characteristics. Therefore, comparing with the original ARNO base flow parameterization used in VIC-3L, the Boussineq equation may offer a great potential in reducing the uncertainties in parameter estimations which is especially important for ungaged basins. The study site is the Usadievskiy watershed at Valdai, Russia, which is a small boreal grassland watershed with its multiple measurements on water fluxes provided by the Project for Intercomparison of Landsurface Parameterization Schemes (PILPS) Phase 2(d). The VIC-ground simulated groundwater table, streamflow, snow water equivalent, evaporation, soil moisture profile and freezing front will be compared with the Valdai observations. Sensitivity of the base flow parameterization based on Boussineq equation on water and energy budgets will be investigated. Also, the uncertainties associated with the two base flow parameterizations will be investigated.
DE: 1800 HYDROLOGY
DE: 1823 Frozen ground
DE: 1833 Hydroclimatology
DE: 1836 Hydrologic budget (1655)
DE: 1860 Runoff and streamflow
SC: Hydrology [H]
MN: 2003 Fall Meeting