impact of climate change on flow in the upper mississippi river basin eugene s. takle iowa state...
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Impact of Climate Change Impact of Climate Change on Flow in the Upper on Flow in the Upper
Mississippi River BasinMississippi River Basin
Eugene S. TakleEugene S. TakleIowa State UniversityIowa State University
Ames, IA 50011 USAAmes, IA 50011 [email protected]@iastate.edu
Project collaborators:Project collaborators:
Manoj Jha, Zaitao Pan, Roy GuManoj Jha, Zaitao Pan, Roy GuRegional-Scale Climate Modelling WorkshopWorld Climate Research ProgrammeLund, Sweden, 29 March - 1 April 2004
If we have perfect If we have perfect predictability of global predictability of global fields, how well can we fields, how well can we
downscale this downscale this predictability to stream predictability to stream
flow at one point?flow at one point?
OutlineOutline Domain and hydrological model (SWAT)Domain and hydrological model (SWAT) Calibration and validationCalibration and validation Observations -> stream flowObservations -> stream flow NNR -> RCM -> SWAT-> stream flowNNR -> RCM -> SWAT-> stream flow GCM -> RCM -> SWAT-> stream flowGCM -> RCM -> SWAT-> stream flow GHGGHG -> GCM -> RCM -> SWAT -> -> GCM -> RCM -> SWAT ->
stream flowstream flow Stream flow vs. precipitationStream flow vs. precipitation Use for policy developmentUse for policy developmentFor details see: Jha, M., Z. Pan, E. S. Takle, and R. Gu, 2003:
Impacts of climate change on stream flow in the Upper MississippiRiver Basin: A regional climate model perspective.Journal of Geophysical Research (in press).
Sub-Basins of theSub-Basins of theUpper MississippiUpper MississippiRiver BasinRiver Basin
119 sub-basins
Outflow measuredat Grafton, IL
Approximately oneobserving stationper sub-basin
Approximately onemodel grid pointper sub-basin
Soil Water Assessment Soil Water Assessment Tool (SWAT)Tool (SWAT)
Long-term, continuous watershed Long-term, continuous watershed simulation model (Arnold et al,1998)simulation model (Arnold et al,1998)
Daily time stepsDaily time steps Assesses impacts of climate and Assesses impacts of climate and
management on yields of water, management on yields of water, sediment, and agricultural chemicalssediment, and agricultural chemicals
Physically based, including hydrology, Physically based, including hydrology, soil temperature, plant growth, soil temperature, plant growth, nutrients, pesticides and land nutrients, pesticides and land managementmanagement
SWAT Output with Various Sources SWAT Output with Various Sources of Climate Inputof Climate Input
Calibration of SWAT:Calibration of SWAT:Annual Stream Flow at Grafton, ILAnnual Stream Flow at Grafton, IL
Calibration of SWAT:Calibration of SWAT:Monthly Stream Flow at Grafton, ILMonthly Stream Flow at Grafton, IL
Validation of SWAT:Validation of SWAT:Annual Stream Flow at Grafton, ILAnnual Stream Flow at Grafton, IL
Validation of SWAT:Validation of SWAT:Monthly Stream Flow at Grafton, ILMonthly Stream Flow at Grafton, IL
RegCM2 Simulation DomainRegCM2 Simulation Domain
Red = global model grid point Green/blue = regional model grid points
Annual Stream Flow Simulated by SWATAnnual Stream Flow Simulated by SWATDriven by the RegCM2 Regional ClimateDriven by the RegCM2 Regional Climate
Model with NNR Lateral Boundary ConditionsModel with NNR Lateral Boundary Conditions
Seasonal Stream Flow Simulated by SWATSeasonal Stream Flow Simulated by SWATDriven by the RegCM2 Regional ClimateDriven by the RegCM2 Regional Climate
Model with NNR Lateral Boundary ConditionsModel with NNR Lateral Boundary Conditions
Mean Monthly Precipitation Simulated by Mean Monthly Precipitation Simulated by the RegCM2 Regional Climate Model the RegCM2 Regional Climate Model
with NNR Lateral Boundary Conditionswith NNR Lateral Boundary Conditions
0
20
40
60
80
100
120
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Snowfall (mm)
RegCM2
SWAT
(a)
(b)
0
10
20
30
40
50
60
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Aver.
Runoff (mm)
RegCM2
SWAT
(c)
0
20
40
60
80
100
120
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Evapotranspiration (mm)
RegCM2
SWAT
(d)
0
20
40
60
80
100
120
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Snowmelt (mm)
RegCM2
SWAT
RegCM2RegCM2 SWATSWAT
EvapotranspirationEvapotranspiration 588588 528528
Surface runoffSurface runoff 151151 166166
SnowmeltSnowmelt 256256 240240
Note: All values are in mm per year averaged for 1980-1988 in NNR run.
Hydrological component comparison between RegCM2 and SWAT
Ten-Year Mean Monthly Stream Flow Generated by the Ten-Year Mean Monthly Stream Flow Generated by the RegCM2 Regional Climate Model Driven RegCM2 Regional Climate Model Driven
with HadCM2 Global Model Results for the with HadCM2 Global Model Results for the Contemporary and Future Scenario (2040s) ClimateContemporary and Future Scenario (2040s) Climate
Ten-Year Mean Precipitation Generated by the RegCM2 Ten-Year Mean Precipitation Generated by the RegCM2 Regional Climate Model Driven with HadCM2 Regional Climate Model Driven with HadCM2
Global Model Results for the Contemporary and Global Model Results for the Contemporary and
Future Scenario (2040s) ClimateFuture Scenario (2040s) Climate
Errors in Simulated Stream FlowErrors in Simulated Stream Flow and Climate Changeand Climate Change
ComparisonsComparisons EvaluateEvaluate
SWAT 1 vs. MeasuredSWAT 1 vs. Measured SWAT errorSWAT error
SWAT 2 vs. SWAT 1SWAT 2 vs. SWAT 1 RCM errorRCM error
SWAT 3 vs. SWAT 2SWAT 3 vs. SWAT 2 GCM errorGCM error
SWAT 3 vs. SWAT 1SWAT 3 vs. SWAT 1 GCM-RCM errorGCM-RCM error
SWAT 2 vs. MeasuredSWAT 2 vs. Measured RCM-SWAT errorRCM-SWAT error
SWAT 3 vs. MeasuredSWAT 3 vs. Measured GCM-RCM-SWAT errorGCM-RCM-SWAT error
SWAT 4 vs. SWAT 3SWAT 4 vs. SWAT 3 Climate changeClimate change
Comparison of Simulated Stream Flow under Comparison of Simulated Stream Flow under Climate Change with Various Model BiasesClimate Change with Various Model Biases
Hydrologic Hydrologic budget budget
componentscomponents
CalibratioCalibrationn
(1989-(1989-1997)1997)
ValidatioValidationn
(1980-(1980-1988)1988)
NNRNNR
(1980-(1980-1988)1988)
CTLCTL
(aroun(around d
1990s)1990s)
SNRSNR
(aroun(around d
2040s)2040s)
% Change (SNR-% Change (SNR-CTL)CTL)
PrecipitationPrecipitation 856856 846846 831831 898898 10821082 2121
SnowfallSnowfall 169169 103103 237237 249249 294294 1818
SnowmeltSnowmelt 168168 9999 230230 245245 291291 1919
Surface runoffSurface runoff 151151 128128 151151 178178 268268 5151
GW rechargeGW recharge 154154 160160 134134 179179 255255 4343
Total water Total water yieldyield
273273 257257 253253 321321 481481 5050
Potential ETPotential ET 947947 977977 799799 787787 778778 -1-1
Actual ETActual ET 547547 541541 528528 539539 566566 55
Hydrologic Budget Components Hydrologic Budget Components
Simulated by SWAT under Different ClimatesSimulated by SWAT under Different Climates
All units are mmYield is sum of surface runoff, lateral flow, and groundwater flow
Relation of Runoff to Precipitation Relation of Runoff to Precipitation for Various Climatesfor Various Climates
Regression Analysis: Regression Analysis:
Stream Flow vs. PrecipitationStream Flow vs. Precipitation
Stream flow vs. precipitation Scenario Slope1. Measured stream flow vs. observed precipitation (1980-1997) Observed 0.662. Simulated stream flow vs. observed precipitation (1980-1988) SWAT 1 0.653. Simulated stream flow vs. RCM/NNR precipitation (1980-1988) SWAT 2 0.874. Simulated stream flow vs. CTL precipitation (around 1990s) SWAT 3 0.645. Simulated stream flow vs. SNR precipitation (around 2040s) SWAT 4 1.16
SummarySummary
RCM provides meteorological detail RCM provides meteorological detail needed by SWAT to resolve sub-basin needed by SWAT to resolve sub-basin variability of importance to streamflowvariability of importance to streamflow
There is strong suggestion that climate There is strong suggestion that climate change introduces changes of magnitudes change introduces changes of magnitudes larger than variation introduced by the larger than variation introduced by the modeling processmodeling process
Relationship of streamflow to Relationship of streamflow to precipitation might change in future precipitation might change in future scenario climatesscenario climates
Future DirectionsFuture Directions
Couple GCM, RCM, SWAT, Crop Couple GCM, RCM, SWAT, Crop Model and Economic ModelModel and Economic Model
Evaluate policy alternatives:Evaluate policy alternatives: Impact of introducing conservation Impact of introducing conservation
practicespractices Impact of introducing incentivesImpact of introducing incentives
Hypothesis:Hypothesis:It is possible to balance profitability It is possible to balance profitability with sustainability in an intensively with sustainability in an intensively managed agricultural area under managed agricultural area under changing climate through changing climate through development of robust policydevelopment of robust policy
Water Quality
PublicPolicy
Incentives
ClimateOver UMRB
Streamflow
SoilDrainage
ManagementChoices
Crop Yield
Land-use
NNR
OBS
Soil Carbon
Evaluate Sustainabilityand Profitability
SWAT
RCM
EconomicModel
CropModel
GCM
OBS
Crop Production
Water Quality
PublicPolicy
Incentives
ClimateOver UMRB
Streamflow
SoilDrainage
ManagementChoices
Crop Yield
Land-use
NNR
OBS
Soil Carbon
Evaluate Sustainabilityand Profitability
SWAT
RCM
EconomicModel
CropModel
GCM
OBS
Crop Production
Without sufficient resolution, it just doesn’t look right.
EST&LM