Paleo-reconstruction of summer streamflow and seasonal uncertainties using the VIC hydrologic model...
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Paleo-reconstruction of summer streamflow
and seasonal uncertainties using the VIC hydrologic model
Eric LutzAlan Hamlet
Jeremy Littell
JISAO CSES Climate Impacts GroupCivil and Environmental Engineering
University of Washington
Climate science in the public interest
Acknowledgments
FundingNOAA CPO SARP (N. Mantua, J. Littell, A. Hamlet, C. Woodhouse)
JISAO
ContributorsJ. Deems ~ Meteorological data processingM. McGuire Elsner ~ VIC implementation
P. Carrasco ~ Programming supportG. Pederson (USGS) ~ Chronologies of the Northern Rockies
Contributors of the International Tree-Ring Data Bank
GoalsI. Reconstruct Seasonal Streamflow
Exploit PNW character: Summer Streamflow driven by Winter Precipitation
Use a physically based hydrologic model (VIC)
Summer Streamflow ~ Winter Precipitation Yakima Basin
r2 = 0.65r2 = 0.73; w/o outlier (1934)
GoalsI. Reconstruct Seasonal Streamflow
Exploit PNW character: Summer Streamflow driven by Winter Precipitation
Use a physically based hydrologic model (VIC)
Summer Streamflow ~ Winter Precipitation
r2 = 0.65r2 = 0.73; w/o outlier (1934)
Goals
II. Quantify Streamflow Uncertainty
Integrate historic meteorological variability into tree-ring based streamflow reconstruction
Develop a physically-based framework for assessing streamflow uncertainty caused by various
factors (Land use change, vegetation dynamic, etc.)
Methods
1. Reconstruct cool season (October-March) precipitation from proxy relationships between historic meteorological data and tree-ring chronologies
2. Create an extended historic meteorological dataset that contains natural variability of the historic record combined with the winter precipitation estimates from the paleo reconstruction.
3. Reconstruct summer streamflow for the period 1600-1981 by driving VIC hydrologic model with the extended historic meteorological datasets.
4. Demonstrate how summer streamflow may be systematically influenced by a climate-change scenario.
Tree-ring Reconstruction of Basin-Average Winter Precipitation
Meteorological RecordMeteorological Record
EOF/PCA, RegressionEOF/PCA, Regression
Historic Record (1916-2006)Paleo Period (1600-1915)
Reconstructed Basin-Average Winter PrecipitationReconstructed Basin-Average Winter Precipitation
Dendrochronological Record (Tree-rings)Dendrochronological Record (Tree-rings)
91 years ofBasin-Average
Winter Precipitation
91 years ofBasin-Average
Winter Precipitation
Tree-ring Reconstruction of Basin-Average Winter Precipitation
‘1937’ ‘1953’ ‘1983’ ‘1933’ ‘1926’
Disaggregate onto multiple winter precipitation patterns
Ensemble of Extended Meteorological Forcings for VIC
High Flow
Pattern
Low Flow
Pattern
Ave. Flow
Pattern
Summer Streamflow ReconstructionHistoric Period (VIC-generated)
Historic Meteorological Patternassociated with
Very high summer flow
Very low summer flow
Average summer flow
Summer Streamflow ReconstructionPaleo-Reconstruction (VIC-generated)
Historic Meteorological Patternassociated with
Very high summer flow
Very low summer flow
Average summer flow
r2 = 0.3
Dalles Streamflow observations (thin black) and long-term linear trend (bold black, p =0.005) compared with reconstructed streamflow (thin red) and long-term linear trend (bold red, p = 0.08).
1860 1880 1900 1920 1940 1960
1500
0025
0000
3500
00
YEAR
Stre
afm
lwo
[cfs
]
Summer Streamflow ReconstructionClimate Change Scenario (VIC-generated)
Historic Meteorological Patternassociated with
Very high summer flow
Very low summer flow
Average summer flow
Summer Streamflow ReconstructionClimate Change Scenario (VIC-generated)
Paleo
Future
Ave. Paleo
Ave. Future
Study Design
Meteorological RecordMeteorological RecordEOF/PCA, RegressionEOF/PCA, Regression
Historic Record(1916-2006)
Paleo Period(1600-1915)
Reconstructed Basin-Average Winter PrecipitationReconstructed Basin-Average Winter Precipitation
Reconstructed StreamflowReconstructed Streamflow
Dendrochronological Record (Tree-rings)Dendrochronological Record (Tree-rings)
Winter PrecipitationSensitivity AnalysisWinter PrecipitationSensitivity Analysis
Spatial & temporal re-distribution of cool-season precipitation
Spatial & temporal re-distribution of cool-season precipitation
Macro-scale hydrological model (VIC)Macro-scale hydrological model (VIC)
Met. Ensemble Representative of Historic Variability
Met. Ensemble Representative of Historic Variability
Extended Distributed Meteorological Data(perturbed independently for Climate Change scenario)
Extended Distributed Meteorological Data(perturbed independently for Climate Change scenario)