recap of water year 2009 hydrologic forecast and forecasts for water year 2010 francisco...
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Recap of Water Year 2009 Hydrologic Forecast and Forecasts for Water Year 2010
Francisco Munoz-ArriolaAlan F. Hamlet Shraddhanand ShuklaDennis P. Lettenmaier
•JISAO/CSES Climate Impacts Group Dept. of Civil and Environmental Engineering
University of Washington
Outline• The UW West-wide Seasonal Hydrological Forecast System
– Hydrology Model
– Ensemble Streamflow Prediction (ESP)
• Recap of Water Year 2009
– ENSO conditions and 2008 Streamflow forecast reliability
• Water year 2010
– Warm ENSO “El Niño Travieso” or the Mischievous Boy
– Land-surface conditions: Soil Moisture (SM) and Surface Water Equivalent (SWE)
• UW-West-wide Seasonal Hydrological Forecast System: Forecasting 2010 streamflow
• Summary
West-Wide Hydrologic Forecast
Soil MoistureState
SnowpackState
VIC
UW West-wide Seasonal Hydrologic Forecast System
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
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
1915 20051960 1999
Streamflow forecast (ESP)
Historical Streamflow (simulated)
1-yr
1-yr[…]
Simulated Streamflow
Recap of WY 2008
ECMRWF ENSO anomaly 2009
0.2
-0.6
-1.0
Predicted Neutral (N)
Observed La Niña (LN)
European Centre for Medium-Range Weather Forecasts
http://www.ecmwf.int/products/forecasts/d/charts/seasonal/forecast/seasonal_range_forecast/nino_plumes_public_s3/
Oct 1st Jan 1st Apr 1st Jul 1st
Soil Moisture and Snow (SWE) Evolution WY 2009
WY 2009 Streamflow Forecast
3.4 Range 2009
-0.6 to 0.2
Ensemble Mean 1961-99
Historical Mean 1961-2000
Ensemble MembersObserved Extremes
Observations WY 2009
Ensemble Mean N years
Validation Plot for 2008 Forecast (1961-2000) at MILNEfor predicted Neutral
3.4 in 2009
~ -1
Ensemble Mean 1961-99
Historical Mean 1961-2000
Ensemble MembersObserved Extremes
Observations WY 2009
Ensemble Mean LN years
Validation Plot for 2008 Forecast (1961-2000) at MILNEbased on the observed LN
Water Year 2010
WY 2008
ENSO Transition States
WY 2009 WY 2010
European Centre for Medium-Range Weather Forecasts
http://www.ecmwf.int/products/forecasts/d/charts/seasonal/forecast/seasonal_range_forecast/nino_plumes_public_s3/
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 2010
1.8
0.9
Forecast of September 2009
150000
200000
250000
300000
350000
400000
450000
-3 -2 -1 0 1 2 3 4
NINO3.4 Index Anomaly
April-September Average
Streamflow
1915-2005
April-September Naturalized Flow for the Columbia River at The MILNE, ID from Historic Water Years vs January Nino 3.4
Anomalies.
The Mischievous Boy or “El Niño Travieso” visits the PNW
NOAA, CFS Precipitation Forecast
Oct-Nov-Dec
Dec-Jan-Feb
IRI-Multi-model Probability Precipitation Forecast
Historical Streamflows (1915-2000)
All Years
Historical Mean 1915-2000
Ensemble MembersObserved Extremes
Ensemble Mean EN years
WY 2010 Forecast
Initial Conditions (changes in weeks)
SM
Sept 25thSept 1st Oct 11th
SWE
Streamflow Forecast on MILNE 1961-2000
All Years
Ensemble Mean 1961-2000
Historical Mean 1961-2000
Ensemble MembersObserved Extremes
3.4 Range 2010
0.9 to 1.8
Based on MILNE Climatology 1961-1999 ESPs
Ensemble Mean 1961-99
Historical Mean 1961-2000
Ensemble MembersObserved Extremes
Ensemble Mean EN years
Forecast and Observed Streamflow Differences
EN ensemble mean - Observed Average (%)
6 months
12 months
MILNE
Streamflow Forecast
http://www.hydro.washington.edu/forecast/westwide/sflow/index.shtml
Summary• Expected Neutral ENSO conditions at the beginning
for the WY 2009 showed good agreement with respect to observed streamflows (simulated) during the Fall-Winter seasons; for streamflow forecast during Sumer of 2009 forecast streamflow was underestimated
• Recent increments in SM over parts of the Snake River Basin have improved the expected streamflows for WY 2010. However, a conspicuous warm phase of ENSO (EN) increase the likelihood of below normal streamflows over the SRB.
• Stations along the mid- and upper SRB showed streamflows 8 to 12% (in average) below historical averaged streamflows for the following 6 months
SWE SM
2008
January June JuneJanuary2009
Soil Moisture and Snow Water Anomalies
Oct 2008 Jan 2009 Jun 2009 Sep 2009
Soil Moisture and Snow Water Equivalent Percentiles
SWE and SM
Simulated
February March April
Climatological
1915 20051960 1999
ESP
Simulated Streamflow from Observations
Simulated
Climatological
SWE and SM for the 2008 and 2009 WY
SWE SM
2008
2009
Based on MILNE Simulated Observations 1915-2005
All Years
Ensemble Mean 1961-99
Observed Mean 1961-2000
Ensemble MembersObserved Extremes
Observations WY 2009
Ensemble Mean N years
UW Forecast System• Less than 10% of the
stations are around the Climatology the rest are below at the North of Columbia river basin
• Around 50% of the stations at the eastern portion of the basin with Stremflows around the climatology
• In the stations related with hydropower generation at 81% ofthe normal
• Dalles at 88% of the normal