HR: 08:45h
AN: H11G-03    [Abstracts]
TI: Characterization of Watershed Model Behavior and Sensitivity-Guided Parameter Estimation Across a Hydroclimatic Gradient
AU: * van Werkhoven, K
EM: klg292@psu.edu
AF: Pennsylvania State University, 212 Sackett Building, University Park, PA 16802, United States
AU: Wagener, T
EM: thorsten@engr.psu.edu
AF: Pennsylvania State University, 212 Sackett Building, University Park, PA 16802, United States
AU: Reed, P
EM: preed@engr.psu.edu
AF: Pennsylvania State University, 212 Sackett Building, University Park, PA 16802, United States
AU: Tang, Y
EM: yxt132@psu.edu
AF: Pennsylvania State University, 212 Sackett Building, University Park, PA 16802, United States
AB: A fundamental tradeoff exists in watershed modeling between a model's flexibility for representing a range of watersheds with varying characteristics versus its potential for over-parameterization. This study uses global sensitivity analysis and multiobjective optimization to evaluate how a medium-complexity model, the Sacramento Soil Moisture Accounting Model (SAC-SMA), represents a wide range of watersheds with varying physical and hydroclimatic characteristics. Initially, Sobol's sensitivity analysis has been used to evaluate SAC-SMA's behavior in twelve Model Parameter Estimation Experiment (MOPEX) watersheds in the US. The watersheds span a wide hydroclimatic gradient from arid to humid systems. Four evaluation metrics reflecting base flows, mid-range flows, peak flows, and long-term water balance were used to comprehensively characterize trends in sensitivity and model behavior. Results show significant variation in parameter sensitivities that are strongly correlated to the hydroclimatic characteristics of the MOPEX watersheds. The sensitivity patterns are consistent with the expected dominant processes in each case and demonstrate the need for moderate model complexity to adequately represent different hydroclimatic regimes. As a final step, the parameter sensitivities have been used to guide an adaptive multiobjective calibration framework and assess the impacts of reducing parameterization requirements for each of the MOPEX watersheds.
DE: 1846 Model calibration (3333)
DE: 1847 Modeling
DE: 1879 Watershed
SC: Hydrology [H]
MN: 2007 Fall Meeting