HR: 08:00h
AN: H31M-01    [Abstracts]
TI: A Framework to Compare Lumped and Distributed Hydrological Models of Climate-Land Surface-Groundwater Dynamics
AU: * Mantilla, R
EM: ricardo@nmt.edu
AF: Earth and Environmental Sciences Department New Mexico Tech, 801 Leroy Pl, Socorro, NM 87801, United States
AU: Gomez, J
EM: jdgomez@nmt.edu
AF: Earth and Environmental Sciences Department New Mexico Tech, 801 Leroy Pl, Socorro, NM 87801, United States
AU: Vivoni, E
EM: vivoni@nmt.edu
AF: Earth and Environmental Sciences Department New Mexico Tech, 801 Leroy Pl, Socorro, NM 87801, United States
AB: We have developed a framework to compare predictions of lumped and distributed hydrological models. Our work is motivated by the need to rigorously identify differences in the parameterization of atmosphere-land- groundwater dynamics across a range of scales. The framework is based on the prediction of the components of the long-term water balance, which can be approximated by the value of fluxes (runoff, evapotranspiration) and state variables (catchment storage) in steady-state conditions. We define the river basin as our control volume for which the mass conservation equation holds. In particular, we focus on the equilibrium catchment storage, discharge-storage relations and ratio of surface to subsurface runoff for different climate conditions. We develop an example comparing two well known hydrological models: the ARNO model, as an example of a lumped- conceptual model, and the tRIBS model, as an instance of a physically based distributed model. We create idealized scenarios in which the parameterizations of both models are consistent. We demonstrate that these two representations of the hydrological system do not yield equal steady-state behavior, and that the incompatibilities are not related to particular model parameters, but to the functional model structure. In particular, we provide an interpretation for the structural differences as a consequence of lateral redistribution of flows in the shallow saturated zone. We also apply the comparison framework to the VIC-2L and VIC-3L models. Finally, we compare the models in a more realistic situation where we incorporate a complex topography overlying an impervious bedrock layer. We argue that the proposed framework can provide insight into the functional behavior of a range of different climate-land surface-groundwater models, with implications toward the need for new observations and theory to accurately capture the dynamics of natural basins.
DE: 1630 Impacts of global change (1225)
DE: 1847 Modeling
DE: 4445 Nonlinear differential equations
SC: Hydrology [H]
MN: 2007 Fall Meeting