Transcript Hydrologic response of Pacific Northwest Rivers to climate change

Hydrologic response of Pacific Northwest Rivers
to climate change
Fengge Su 1, Lan Cuo2, Huan Wu3, Nate Mantua1,
Dennis P. Lettenmaier1
1University
of Washington, Seattle, WA 98195
2University of Victoria, BC Canada V8W 2Y2
3 University of Montana, Missoula, MT 59812
2016/4/11
Background
North Pacific Rim
Pacific Ocean
Pacific Northwest
4/11/2016
A warming climate will alter:
• the snow pack
• seasonality of streamflow
• magnitude and frequency of
peak flow and low flow events
• Water temperatures
• Changes in hydrologic regime
and stream temperature have
the potential to negatively
impact the Pacific wild
salmon.
Experimental Design
downscaled Climate data (T, P) for
2010-2098
Hydrologic model for
streamflow simulations
Floodplain
habitat model
Energy balance model
for stream temperature
simulations
Statistically downscale coarse-resolution temperature and
precipitation change scenarios from global climate models; use
these as forcings in a finer scale hydrologic model to produce
streamflow and temperature change scenarios.
4/11/2016
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Hydrology Model and dataset
Hydrology model: VIC
Study domain: shaded area
Resolution: 1/8
Number of grids: 146351
Pacific Northwest
4/11/2016
Input:
Daily precipitation, Tmax, Tmin, and Wind
speed.
Derived input: Downward Solar and long
wave, vapor pressure deficit
Observed meteorology: daily P, Tmax, Tmin,
Wind for 1950-1999 (global, 0.5 degree)
(Maurer et al. 2009; Adam and Lettenmaier 2003)
Output:
Daily runoff, soil moisture, evaporation, and
snow water equivalent
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Bias correction and spatial downscaling
scheme for GCM output (Wood et al., 2002, 2004)
Raw monthly P &T from 20 GCMs in IPCC AR4 under
scenarios B1, A1B at 0.5-3.5 degree, 2010-2098
Bias correction
Downscaling from 2.0 to 0.5
degree, monthly to daily
Regridding from 0.5 to 0.125
degree
with respect to observed climatology for
the period 1950-1999 at 2.0 degree
with respect to observed climatology for
the period 1950-1999 at 0.5 degree
Using nearest neighbor approach
Bias correction: Quantile-Quantile technique with
respect to observed climatology (1950-1999)
Raw GCM
value
Bias corrected
GCM value
Raw GCM cdf
Observed data cdf
Prcp CDF,
monthly,2degree, grid
data_47.00_121.00
Temp CDF,
monthly,2degree,grid
data_47.00_121.00
Monthly average precipitation (2070-2098) from one
GCM -BCCR (Bjerknes Centre for Climate Research in Norway)
Raw GCM output,
2.0 degree
bias corrected and
downscaled map, 0.5 degree
mm/mon
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Average of 20 GCMs bias-corrected temperature
changes under Scenario A1B
1960-1999
ºC
2040-2069
2070-2098
ºC
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Average of 20 GCMs bias-corrected precipitation
changes under Scenario A1B
1960-1999
mm/mon
2040-2069
2070-2098
mm/mon
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Hydrologic response to projected climate
change -case study in Colombia River Basin
Willamette River
4/11/2016
Salmon river
Resolution: 1/8 degree
Historic run: 1960-1999
Future run: 2000-2098
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Projected precipitation and temperature for the basins of
Salmon and willamette
Salmon
2010-2039
Willamette
Salmon
Willamette
2010-2039
2010-2039
2010-2039
2070-2098
2040-2069
2070-2098
Temperature (ºC)
Precipitation (mm)
2040-2069
2040-2069
2040-2069
2070-2098
1 2 3 4 5 6 7 8 9 10 11 12
1 2 3 4 5 6 7 8 9 10 11 12
1 2 3 4 5 6 7 8 9 10 11 12
Single GCM
4/11/2016
2070-2098
GCM average
1 2 3 4 5 6 7 8 9 10 11 12
Historical
(1960-1999)
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Projected streamflow for the basins of Salmon,
and willamette
Salmon
Willamette
2010-2039
2010-2039
Single GCM
GCM average
Historical
(1960-1999)
•
Streamflow (m3/s)
2040-2069
2040-2069
•
2070-2098
2070-2098
•
1 2 3 4 5 6 7 8 9 10 11 12
4/11/2016
1 2 3 4 5 6 7 8 9 10 11 12
The salmon is a snow-melt
dominant basin, while
Willamette is a rain dominant
basin.
The spring peak flow is
projected to appear earlier in
the Salmon basin in
connection with an earlier
snow melt.
The Willamette basin is
projected to have an
increasing cool season flow
as a result of increasing
winter precipitation.
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Analysis underway …
• see our POSTER on stream temperature simulations:
Climate Change impacts on the hydrology and
temperature of Pacific Northwest streams (1340h
H33E-0929, Wednesday )
• How will a changing climate affect summer low flows
and flood peaks?
• How will a changing climate affect snow water
equivalent (SWE) in Spring?
• How will a changing climate and hydrologic regime
affect stream temperature?
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Thank You!
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