recap of water year 2008 hydrologic forecast and forecasts for water year 2009 francisco...
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Recap of Water Year 2008 Hydrologic Forecast and Forecasts for Water Year 2009
Francisco Munoz-ArriolaAlan F. Hamlet Shraddhanand ShuklaDennis P. Lettenmaier
•JISAO/CSES Climate Impacts Group Dept. of Civil and Environmental Engineering
University of Washington
Recap of WY 2008
ECMRWF ENSO anomaly 2008
European Centre for Medium-Range Weather Forecasts
Validation Plot for 2008 Forecast (All Cool ENSO composite)
Mod
ified
Flo
w (
cfs)
The Dalles
150000
200000
250000
300000
350000
400000
450000
-3 -2 -1 0 1 2 3 4
NINO3.4 Index Anomaly
Ap
ril-
Se
pte
mb
er
Av
era
ge
S
tre
am
flo
w
1916-2002
April-September Naturalized Flow for the Columbia River at The Dalles, OR from Historic Water Years vs January Nino 3.4 Anomalies.
5000
10000
15000
20000
25000
30000
-3 -2 -1 0 1 2 3 4
Nino 3.4 Anomaly (C)
Apr
il-S
epte
mbe
r A
vg N
atur
aliz
ed
Str
eam
flow
(cf
s)
Natural Flows at Milner 1928-1989
Nat
ural
Flo
w (
KA
F)
Red = long term meanBlue = ensemble meanGray = ensemble membersBlack = range of observations
Simulated Natural Flow at Milner (ESP all years)
Milner
Nat
ural
Flo
w (
KA
F)
Red = long term meanBlue = ensemble meanGray = ensemble membersBlack = range of observations
Simulated Natural Flow at Milner (ESP cool ENSO)
Milner
WY 2008 Forecast
WY 2007 WY 2008
Potential Implications of ENSO Transition States
WY 2009
http://www.ecmwf.int/products/forecasts/d/charts/seasonal/forecast/seasonal_range_forecast/nino_plumes_public_s3/
European Centre for Medium-Range Weather Forecasts
ECMRWF ENSO anomaly 2009
0.2
-0.6
150000
200000
250000
300000
350000
400000
450000
-3 -2 -1 0 1 2 3 4
NINO3.4 Index Anomaly
Ap
ril-
Se
pte
mb
er
Av
era
ge
S
tre
am
flo
w1916-2002
April-September Naturalized Flow for the Columbia River at The Dalles, OR from Historic Water Years vs January Nino 3.4 Anomalies.
Natural Flows at Milner 1928-1989
West-Wide Hydrologic Forecast
UW Forecast Approach Schematic
NCDC COOP station obs.
up to 3 months from
current
local scale (1/8 degree) weather inputs
soil moisturesnowpack
VIC Hydrologic model spin up
SNOTEL
Update
streamflow, soil moisture, snow water equivalent, runoff
25th Day, Month 01-2 years back
index stn. real-time
met. forcings for spin-up
gap
Hydrologic forecast simulation
Month 12
INITIAL STATE
ObservedSWE
Assimilation
ensemble forecasts ESP traces CPC-based outlook NCEP CFS ensemble NSIPP-1 ensemble
West-wide System
Ensemble Streamflow Prediction (ESP)
ICsSpin-up Forecast
observed
recentmet data to generate
“perfect” ICs
ensemble of historical met datato generate ensemble
forecast
hydrologicstate
Applications: climate forecast
Soil Moisture and Snow Water Anomalies
SWE and SM
SimulatedClimatological
March AprilFebruary
SWE and SM
SimulatedClimatological
MarchFebruary April
July August September
Based on Milner Climatology 1960-2005
All Years
Ensemble Mean
Climatological Mean
Ensemble Members
Climatological Extremes
0
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400000
600000
800000
1000000
S O N D J F M A M J J A
Nat
ura
l Str
eam
flo
w (
cfs)
Based on Dalles Climatology 1901-2005
All Years
Ensemble Mean
Climatological Mean
Ensemble Members
Climatological Extremes
Based on Milner Climatology 1960-2005
ENSO-Neutral Years
Ensemble Mean
Climatological Mean
Ensemble Members
Climatological Extremes
0
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400000
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800000
1000000
1200000
S O N D J F M A M J J A
Nat
ura
l Str
eam
flo
w (
cfs)
Based on Dalles Climatology 1901-2005
ENSO-Neutral Years
Ensemble Mean
Climatological Mean
Ensemble Members
Climatological Extremes
3.4 Range 2009
-0.6 to 0.2
Based on Milner Climatology 1901-2005
Ensemble Mean
Climatological Mean
Ensemble Members
Climatological Extremes
0
200000
400000
600000
800000
1000000
1200000
S O N D J F M A M J J A
Nat
ura
l Str
eam
flo
w (
cfs)
3.4 Range 2009
-0.6 to 0.2
Based on Dalles Climatology 1901-2005
Ensemble Mean
Climatological Mean
Ensemble Members
Climatological Extremes
West-Wide Hydrologic Forecast
West Wide Forecast (1961-2000)
All Years
Ensemble Mean
Climatological MeanEnsemble Members
Climatological Extremes
ENSO-years Mean (N)
Milner
0
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400000
600000
800000
1000000
S O N D J F M A M J J A
Nat
ura
l Str
eam
flo
w (
cfs)
West Wide Forecast (1961-2000)
All Years
Ensemble Mean
Climatological MeanEnsemble Members
Climatological Extremes
ENSO-years Mean (N)
Dalles
ENSO-Neutral Years
West Wide Forecast (1961-2000)
Ensemble Mean
Climatological MeanEnsemble Members
Climatological Extremes
ENSO-years Mean (N)
Milner
0
200000
400000
600000
800000
1000000
S O N D J F M A M J J A
Na
tura
l S
tre
am
flo
w (
cfs
)
ENSO-Neutral Years
West Wide Forecast (1961-2000)
Ensemble Mean
Climatological MeanEnsemble Members
Climatological Extremes
ENSO-years Mean (N)
Dalles
3.4 Range 2009
-0.6 to 0.2
West Wide Forecast (1961-2000)
Ensemble Mean
Climatological MeanEnsemble Members
Climatological Extremes
ENSO-years Mean (N)
Milner
0
200000
400000
600000
800000
1000000
S O N D J F M A M J J A
Na
tura
l S
tre
am
flo
w (
cfs
)
3.4 Range 2009
-0.6 to 0.2
West Wide Forecast (1961-2000)
Ensemble Mean
Climatological MeanEnsemble Members
Climatological Extremes
ENSO-years Mean (N)
Dalles
UW Forecast System in the Snake River
Hells Canyon Dam
Milner
UW Forecast System in the Hydropower-related stations at the
Columbia River
Grand Coulee
Chief Joseph Dam
Conclusions:•Cool ENSO event during the winter of 2007-2008, increased above average Apr-Sep flow at Milner•High snowpack during winter-spring was associated with low values in soil moisture•The WY 2008 ESP forecast predicted increased likelihood of wet conditions. Observed summer flows at Milner in 2007 were above average (~25% of normal for April-Sept)•Current soil moisture conditions may contribute to slightly reduce streamflow generation during the Jan-June period by 3%.•The west-wide forecast system predicts flows similar to those observed in the climatologies for the Dalles , However for the Milner stations there is a increased likelihood of drought and consequently flows slight below normal for the coming water year.•Slightly below 1961-2000 climatological values•Slightly above -0.6-to-0.2 ENSO neutral values•On the average of ENSO neutral years
WY 2007 WY 2008
Potential Implications of ENSO Transition States
1904 1.47
1907 1.00
1921 1.00
1925 0.49
1932 0.39
1943 0.88
1965 0.90
1971 1.55
1974 2.22
1984 0.58
1989 -0.40
1996 0.93
1999 0.89
Historic Dalles Apr-Sept streamflow anomalies for water years with previous winter warm ENSO, current winter cool ENSO
Stats:
12 of 13 above 0.39
11 of 13 above 0.49
9 of 13 above 0.88
WY Std Ann.
Nat
ural
Str
eam
flow
(cf
s)Based on Dalles Climatology 1901-2003
1932 -0.235
1943 1.137
1965 1.238
1971 2.170
1974 1.686
1984 1.883
1989 -0.080
Historic Milner Apr-Sept streamflow anomalies for water years with previous winter warm ENSO, current winter cool ENSO
WY Std Ann.
Stats:
5 of 7 above 1.1
3 of 7 above 1.7
enso_2008 enso_trans_2008
Based on Milner ESP 1961-2000N
atur
al F
low
(K
AF
)
Nat
ural
Flo
w (
KA
F)