Impacts of hydrological variability and change on water resources

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Impacts of hydrological variability and change on
water resources
Dennis P. Lettenmaier Department of Civil and
Environmental Engineering University of
Washington for presentation at Fifth IHP/IAHS
George Kovacs Colloquium UNESCO, Paris 2 June 2000
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Outline of this talk
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Modeling the Connections Between Climate and
Streamflow
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Currently Modeled US Basins
1 Northwest 5 Rio Grande 10 Upper Mississippi 2
California 6 Missouri 11 Lower Mississippi 3
Great Basin 7 Arkansas-Red 12 Ohio 4 Colorado 8
Gulf 13 East Coast 9 Great Lakes
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Schematic for Forecasting Experiments Using
Resampled Observed Data
Select Met Data Ensemble from Historic Record
Associated with Forecast Climate Category
Long-Lead Climate Forecast
ENSO
Run Initialized Hydrologic Model
PDO
Ensemble Streamflow Forecast
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Columbia PDO Effects
Columbia ENSO Effects
PDO/ENSO Effects
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Chester Morse PDO Effects
Chester Morse ENSO Effects
PDO/ENSO Effects
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Time Line for 12-month Lead Time Retrospective
Forecasts
Climate Forecast
Estimated Initial Conditions
Forecast Ensemble
Lead time 12 months
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Columbia River Streamflow Forecast at The Dalles
for 2001
Highest Simulation (1948-1997)
Cool PDO/ENSO Neut. Ensemble
Lowest Simulation (1948-1997)
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Columbia River Streamflow Forecast at The Dalles
for 2000
Cool PDO/Cool ENSO Ensemble
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Overview of Streamflow Forecasting Schemes Using
Climate Models
Global Climate Models
Water Resources Models
Hydrology Models
streamflow
Temp. Precip. wind
downscaling
Regional Climate Models
water demand
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Constructing the Hydrology Model Driving Data
Using a Normal SST Nov-Apr Climate Forecast
MM5 Sim
24 MM5 Forecasts
MM5 Sim
MM5 Sim
MM5 Sim
MM5 Sim
MM5 Sim
MM5 Sim
MM5 Sim
Nov
Dec
Feb
Mar
Apr
Jan
MM5 Sim
MM5 Sim
MM5 Sim
MM5 Sim
MM5 Sim
MM5 Sim
. . .
. . .
1960
Oct
May
Jun
Jul
Repeating 1960 Observed Temp and Precip Time
Series with Nov-April Replaced by MM5 Forecasts
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Test Simulations for the Columbia River at The
Dalles
Control (observed Nov-Aprs)
RCM (raw climate simulations for Nov-Aprs)
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Simple Bias Correction Used in MM5
Experiments (Nov-Mar Ensembles inserted in
repeating 1960)
Mean
Variance
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Quantile Mapping Bias Correction
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Kanawha River Basin Simulations Using Observed
Data and Bias Corrected GCM Output
Mean
Observations Bias-Corrected GCM
Variance
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Downscaled GSM forecast ensembles compared to
historical climatological bounds
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Current Streamflow Forecast Basins
1 Ohio 3 Delaware 4
Alabama-Coosa-Tallapoosa 2 Potomac 5
Apalachicola-Chattahoochee-Flint
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Current Streamflow Forecast Basins
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Climate Scenarios
Adjustments To Observed Meteorology
Performance Measures
Transient GCM Simulations for Increasing CO2 and
Aerosols
Delta Precip, Temp
Reliability of System Objectives
Reservoir Model (ColSim)
Hydrologic Model (VIC)
DamReleases, Regulated Streamflow
Natural Streamflow
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2025
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2045
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ColSim Reliability of System Objectives