HR: 1340h
AN: H33C-1449    [Abstracts]
TI: SABAE-HW3D: a Meteor-Hydrological Model Coupling the Land Surface to Groundwater Flow
AU: * Loukili, Y
EM: loukili@cc.umanitoba.ca
AF: University of Manitoba, Department of Civil Engineering, Engineering Building, 15 Gillson Street, Winnipeg, MB R3T 5V6, Canada
AU: Woodbury, A D
EM: woodbur@cc.umanitoba.ca
AF: University of Manitoba, Department of Civil Engineering, Engineering Building, 15 Gillson Street, Winnipeg, MB R3T 5V6, Canada
AB: A new coupled model linking the land surface scheme SABAE-HW with the saturated groundwater flow is introduced. SABAE-HW stands for: Soil Atmosphere Boundary, Accurate Evaluations of Heat and Water. It was presented (Loukili et al., 2007) as a parallel extension to the Canadian LAnd Surface Scheme (CLASS) which permits a free choice of soil column depth and layers. This development is important as it allows for the coupling of the atmosphere, land surface and subsurface zones. The generic domain under study is subdivided into soil columns whose surface areas represent GCM grid squares. The depths of columns extend to the saturated zone where a water table lower boundary condition is prescribed. In each column the unsaturated flow is forced by the corresponding meteorological data, and the moisture (liquid and frozen) and temperature profiles are computed by SABAE-HW using the half hour time step. The horizontal flow in the saturated zone is described by the vertically integrated model incorporating a storage term, and discretized using a finite volume scheme operating on the same GCM quadrilateral mesh. Since the saturated flow model affords larger time steps, bottom drainages from soil columns are summed up and input as cell recharges. Meanwhile, as the water table fluctuates, the individual column's mesh is allowed to deform. This physically based coupling strategy was selected for its superiority in providing stable and consistent results. In fact, the convergence to steady state situations in both the unsaturated and saturated zones is realized in many validation numerical tests. Moreover, our SABAE-HW3D code was successfully benchmarked against the finite element code Seep/W (Geo-Slope International, 2002) for steady and transient groundwater flows through different soil types. Even when handling coarse grids, SABAE-HW3D solutions are free of moisture oscillation and under or overshoot near the water table. The model is used to understand and assess properly regional moisture exchanges between the atmosphere and the ground in the Canadian Prairies. The ultimate goal is to investigate the onset and persistence of drought.
DE: 1805 Computational hydrology
DE: 1829 Groundwater hydrology
DE: 1830 Groundwater/surface water interaction
DE: 1843 Land/atmosphere interactions (1218, 1631, 3322)
DE: 1847 Modeling
SC: Hydrology [H]
MN: 2007 Fall Meeting