recap of water year 2009 hydrologic forecast and forecasts for water year 2010 francisco...

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 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





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



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




3.4 Range 2010

0.9 to 1.8

Based on MILNE Climatology 1961-1999 ESPs




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


Observed Mean 1961-2000



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

recap of water year 2009 hydrologic forecast and forecasts for water year 2010 francisco...

Documents

ensemble slide

streamflow forecast

climate forecast slide

s3 slide

neutral slide

streamflow summary slide

observed ln slide

yr simulated streamflow