Download 2006 Water Resources Outlook for Idaho and the

2006 Water Resources Outlook
for Idaho and the Western U.S.
JISAO Center for Science in the Earth System
Climate Impacts Group
and Department of Civil and Environmental Engineering
University of Washington
October, 2006
http://www.hydro.washington.edu/Lettenmaier/Presentations/2004/hamlet_2006_forecast_oct_2005.ppt
Alan F. Hamlet
Andy Wood
Dennis P. Lettenmaier
Background
Background: Forecast System Schematic
local scale (1/8 degree)
weather inputs
Hydrologic
model spin up
NCDC met.
station obs.
up to 2-4
months from
current
1-2 years back
LDAS/other
real-time
met. forcings
for spin-up
gap
soil moisture
snowpack
INITIAL
STATE
streamflow, soil moisture,
snow water equivalent, runoff
Hydrologic forecast
simulation
ensemble forecasts
SNOTEL
SNOTEL
/ MODIS*
Update
Update
25th Day, Month 0
ESP traces (40)
CPC-based outlook (13)
NCEP GSM ensemble (20)
NSIPP-1 ensemble (9)
Month 6 - 12
* experimental, not yet in real-time product
Background: Hydrology Model
Background: Estimating Initial Conditions
SNOTEL assimilation
Assimilation Method
• weight station OBS’ influence over VIC cell based on distance and
elevation difference
• number of stations influencing a given cell depends on specified
influence distances
• distances “fit”: OBS
weighting increased
throughout season
• OBS anomalies applied to
VIC long term means,
combined with VIC-simulated
SWE
• adjustment specific to each
VIC snow band
spatial weighting function
elevation
weighting
function
SNOTEL/ASP
VIC cell
Background:
Streamflow Forecast
Locations
California
Columbia R. basin
in development:
Colorado R.,
Upper Rio Grande
Snake R.
basin
Linkage to Reservoir Models
Streamflow
Forecast
Bias Correction
Reservoir Model
Observed Reservoir
Contents
Demand Scenarios
Storage
Ensemble
Recap of Water Year 2005
Observed Nino3.4 anomally
Natural Flows at Milner 1928-1989
April-September Avg Naturalized
Streamflow (cfs)
30000
25000
20000
15000
10000
5000
-3
-2
-1
0
1
2
Nino 3.4 Anomaly (C)
3
4
Natural Streamflow (KAF)
Simulated Natural Flow at Milner (Oct ESP Nino3.4
between +0.2 and +1.2) (data from 1960-2002 period)
WY 2005
http://www.hydro.washington.edu/forecast/westwide/archive/spatial/columbia.shtml
http://www.hydro.washington.edu/forecast/westwide/archive/spatial/columbia.shtml
Probability of Exceedence Plot for Natural Flow at
Milner from WY 2005 Forecast
April-Sept streamflow
volume (KAF)
12000
10000
8000
6000
4000
2000
0
0
0.2
0.4
0.6
0.8
Probabilty of Exceedence
1
System Storage
Forecast from
SnakeSim:
Nino3.4 anomaly
between 0.2 and
1.2 C
Demand aligned
with water cond.
Active Reservoir Storage (kaf)
Jackson Lake
Palisades
Island Park
Ririe
American Falls
Lake Walcott
October 1 Spin Up
Obs. System
Storage Oct 1, 2005
Outlook for Water Year 2006
April 1 SWE (mm)
Winter Climate
Forecasts Dominate
June
December
Hydrologic State
Variables Dominate
March
http://www.hydro.washington.edu/forecast/westwide/
Initial Soil Moisture Conditions
Oct 1, 2004
UW West Wide Seasonal Hydrologic Forecast System
http://www.hydro.washington.edu/forecast/westwide/sflow/index.shtml
UW West Wide Seasonal Hydrologic Forecast System
http://www.hydro.washington.edu/forecast/westwide/sflow/index.shtml
Used range:
Jan3.4 >= -0.4
Jan3.4 <= 0.6
Used range:
Jan3.4 >= 0.0
Jan3.4 <= 0.6
Natural Flows at Milner 1928-1989
April-September Avg Naturalized
Streamflow (cfs)
30000
25000
20000
15000
10000
5000
-3
-2
-1
0
1
2
Nino 3.4 Anomaly (C)
3
4
Natural Streamflow (KAF)
Climatology of Naturalized Streamflow in the Snake River at Milner
Milner
Climatology
1928-1992
Natural Streamflow (KAF)
Red = long term mean
Blue = ensemble mean
Gray = ensemble members
Black = range of observations
WY 2006
Natural Streamflow (KAF)
Red = long term mean
Blue = ensemble mean
Gray = ensemble members
Black = range of observations
Natural Streamflow (KAF)
PDO ENSO Forecast for Milner Assuming “Neutral PDO Years”
And Nino3.4 between -0.4 and 0.6
System Storage
Forecast from
SnakeSim:
Nino3.4 anomaly
between -0.4 and
0.6 C
Demand aligned
with water cond.
Active Reservoir Storage (kaf)
Jackson Lake
Palisades
Island Park
Ririe
American Falls
Lake Walcott
October 1 Spin Up
Summary of 2006 Forecast
Current soil moisture on Oct, 2005 is relatively wet in southern Idaho,
and relatively dry in northern Idaho.
ENSO neutral conditions are likely in WY 2006, with forecast Nino3.4
anomalies ranging from about 0.0 to 0.6 in mid winter.
Probability distributions for streamflow in ENSO neutral years are
similar in character to the climatology overall. The central tendency
of the WY 2006 streamflow forecast at Milner is near the long term
mean for both ENSO and PDO/ENSO composites. Risks of very high
or very low flows are somewhat reduced, but very high and low flow
events have occurred for similar ENSO/PDO conditions in the past.
Carryover storage in the upper Snake reservoirs is improved from
last year, and the reservoir system forecast suggests peak reservoir
storage levels of about 3000 KAF in April or May, 2006, and
carryover storage in Sept, 2006 of about 1000 KAF.
Climate Change Planning Activities
Snake River Planning Data Resources
Weekly time step surrogate observations and climate change
streamflow scenarios for the Snake basin are currently
available:
ftp://ftp.hydro.washington.edu/pub/hamleaf/snakesim/
USBR planning study for the Flathead
•Draft daily flow scenarios are completed
•Preliminary reservoir model analysis in progress
New GCM Scenarios from the IPCC 4th Assessment
CIG Climate Change Reports and White Papers for King
Co. Planning Meeting and Puget Sound Action Team
Overview of Experimental EnergyRelated Forecasting Products
Covariation of Normalized PNW and CA
Hydropower Production
3.000
2.000
PNW*
CA*
1.000
0.000
-1.000
-2.000
R2 =0.541
-3.000
191719221927193219371942194719521957 196219671972197719821987199219972002
California hydropower is less than 10% of total CA demand, but
may play a significant role in energy trading on short time
scales.
Probability of Exceedance for Spring Surplus Energy
Resources in the PNW
Voisin, N., A. F. Hamlet, L. P. Graham, D. W. Pierce, T. P. Barnett, and D. P.
Lettenmaier, 2005: The role of climate forecasts in western U.S. power planning,
Journal of Applied Meteorology (accepted).