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Global Sensitivity of Simulated Water Balance Indicators Under Future Climate Change in the Colorado Basin
Author(s) -
Bennett Katrina E.,
Urrego Blanco Jorge R.,
Jonko Alexandra,
Bohn Theodore J.,
Atchley Adam L.,
Urban Nathan M.,
Middleton Richard S.
Publication year - 2018
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1002/2017wr020471
Subject(s) - evapotranspiration , environmental science , streamflow , baseflow , surface runoff , climate change , water balance , albedo (alchemy) , downscaling , sensitivity (control systems) , leaf area index , snow , hydrology (agriculture) , water cycle , uncertainty analysis , climate model , climatology , precipitation , drainage basin , meteorology , geography , mathematics , geology , ecology , statistics , art , electronic engineering , engineering , biology , art history , cartography , geotechnical engineering , performance art , oceanography
The Colorado River Basin is a fundamentally important river for society, ecology, and energy in the United States. Streamflow estimates are often provided using modeling tools which rely on uncertain parameters; sensitivity analysis can help determine which parameters impact model results. Despite the fact that simulated flows respond to changing climate and vegetation in the basin, parameter sensitivity of the simulations under climate change has rarely been considered. In this study, we conduct a global sensitivity analysis to relate changes in runoff, evapotranspiration, snow water equivalent, and soil moisture to model parameters in the Variable Infiltration Capacity (VIC) hydrologic model. We combine global sensitivity analysis with a space‐filling Latin Hypercube Sampling of the model parameter space and statistical emulation of the VIC model to examine sensitivities to uncertainties in 46 model parameters following a variance‐based approach. We find that snow‐dominated regions are much more sensitive to uncertainties in VIC parameters. Although baseflow and runoff changes respond to parameters used in previous sensitivity studies, we discover new key parameter sensitivities. For instance, changes in runoff and evapotranspiration are sensitive to albedo, while changes in snow water equivalent are sensitive to canopy fraction and Leaf Area Index (LAI) in the VIC model. It is critical for improved modeling to narrow uncertainty in these parameters through improved observations and field studies. This is important because LAI and albedo are anticipated to change under future climate and narrowing uncertainty is paramount to advance our application of models such as VIC for water resource management.