seasonal outlooks for hydrology and water resources in the pacific northwest andy wood alan hamlet...
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Seasonal outlooks for hydrology and water resources in the Pacific Northwest
Andy Wood Alan Hamlet
Dennis P. Lettenmaier
Department of Civil and Environmental Engineering
for Climate and Water Resource Forecasts for the 2006 Water Year
UW Climate Impacts Group
October 26, 2005, Seattle
Presentation Outline
1. Introduction: UW Experimental Hydrologic
Forecasting System
2. Water Year 2005 Assessment
3. Water Year 2006 Outlook
Average annual water cycle
Introduction: A review of the PNW hydrologic cycle
PNW
Where we are now on average
soil moisture near annual low
runoff near low
nearly all water year precipitation yet to come
snow season not really underway
evaporation not a factor
Oct 1 ESP fcst: Summer Volumes
Introduction
Forecast System Website
Experimental W. US Hydrologic Forecast System
Soil MoistureInitial
Condition
SnowpackInitial Condition
Experimental W. US Hydrologic Forecast System
ESP
ENSO/PDO
ENSO
CPC Official Outlooks
Coupled Forecast System
CAS
OCN
SMLR
CCA
CA
NSIPP/GMAO dynamical
model
VIC Hydrology Model
NOAA
NASA
UW
Multiple Seasonal Climate Forecast Data Sources
Hydrologic prediction using ESP
NWS River Forecast Center (RFC) approach:
rainfall-runoff modeling(i.e., NWS River Forecast System,
Anderson, 1973 offspring of Stanford Watershed Model, Crawford & Linsley, 1966)
Ensemble Streamflow Prediction (ESP)
• used for shorter lead predictions;• increasingly used for longer lead
predictions
ICsSpin-up Forecast
obs
recently observedmeteorological data
ensemble of met. datato generate forecast
ESP forecast
hydrologicstate
targeted statisticse.g., runoff volumes
monthly hydrographs
spatial forecast maps
Presentation Outline
1. Introduction: UW Experimental Hydrologic Forecasting
System
2. Water Year 2005 Assessment
3. Water Year 2006 Outlook
Recap WY2005, Dec. 1 hydrologic conditions
Recap WY2005, Jan. 1 hydrologic conditions
Recap WY2005, Feb. 1 hydrologic conditions
Recap WY2005, Mar. 1 hydrologic conditions
Recap WY2005, Apr. 1 hydrologic conditions
Recap WY2005, May. 1 hydrologic conditions
Recap WY2005, Jun. 1 hydrologic conditions
Current WY2005, Oct. 1 hydrologic conditions
Oct. 1 Soil Moisture Comparison
THIS YEAR LAST YEAR
Streamflow volume forecasts
UPPER HUMBOLDT RIVER BASIN
Streamflow Forecasts - May 1, 2003
<==== Drier === Future Conditions === Wetter ====>
Forecast Pt ============ Chance of Exceeding * ===========
Forecast 90% 70% 50% (Most Prob) 30% 10% 30 Yr Avg
Period (1000AF) (1000AF) (1000AF) (% AVG.) (1000AF) (1000AF) (1000AF)
MARY'S R nr Deeth, Nv
APR-JUL 12.3 18.7 23 59 27 34 39
MAY-JUL 4.5 11.3 16.0 55 21 28 29
LAMOILLE CK nr Lamoille, Nv
APR-JUL 13.7 17.4 20 67 23 26 30
MAY-JUL 11.6 15.4 18.0 64 21 24 28
N F HUMBOLDT R at Devils Gate
APR-JUL 5.1 11.0 15.0 44 19.0 25 34
MAY-JUL 1.7 7.2 11.0 50 14.8 20 22
Winter 2004-05: seasonal volume forecast for APR-SEP flow
ESP median, 10th & 90th %-ilesESP-ENSO (warm) median
OBS
Forecasts made on 1st of Month
Winter 2004-05: seasonal volume forecast for APR-SEP flow
ESP median, 10th & 90th %-ilesESP-ENSO (warm) median
OBS
Forecasts made on 1st of Month
Winter 2004-05: seasonal volume forecast for APR-SEP flow
ESP median, 10th & 90th %-ilesESP-ENSO (warm) median
OBS
Forecasts made on 1st of Month
Winter 2004-05: seasonal volume forecast for APR-SEP flow
ESP median, 10th & 90th %-ilesESP-ENSO (warm) median
OBS
Forecasts made on 1st of Month
Winter 2004-05: seasonal volume forecast for APR-SEP flow
ESP median, 10th & 90th %-ilesESP-ENSO (warm) median
OBS
Forecasts made on 1st of Month
Presentation Outline
1. Introduction: UW Experimental Hydrologic Forecasting
System
2. Water Year 2005 Assessment
3. Water Year 2006 Outlook
Basin Average Water Balance Perspective
Averaging water balance variables over a region can help characterize the evolution of the water year
forecast distribution
max
0.75median0.25
min
spinup
Oct 1 ESP fcst: WY2006 Precip, Temp
Columbia R. basin upstream of The
Dalles, OR
Precip Temp
2005 2006 2005 2006
Oct 1 ESP fcst: WY2006 SM, SWE, RO
Runoff
hangover fromlast year’s soil moisture deficitApr-Sep % of
avg
ESP: 98%ENSO: 95%
Soil Moist
SWE
2005 2006
Oct 1 ESP fcst: WY2006 Precip, Temp
Precip Temp
2005 2006
Puget Sound Drainage Basin
2005 2006
Oct 1 ESP fcst: WY2006 SM, SWE, RO
Apr-Sep % of avg
ESP: 98%ENSO: 96%
Runoff
Soil Moist
SWE2005 2006
Oct 1 ESP fcst: WY2006 Precip, Temp
Precip Temp
2005 2006
Yakima R. Basin near
Parker, WA
2005 2006
Oct 1 ESP fcst: WY2006 SM, SWE, RO
Apr-Sep % of avg
ESP: 93%ENSO: 90%
RunoffSoil Moist
SWE2005 2006
Oct 1 ESP fcst: WY2006 Precip, Temp
Precip Temp
2005 2006 2005 2006
BC portion of Columbia R. Basin
Oct 1 ESP fcst: WY2006 SM, SWE, RO
Apr-Sep % of avg
ESP: 101%ENSO: 99%
RunoffSoil Moist
SWE2005 2006
Conclusions
It’s still early in year for hydrologic forecasts, especially in an ENSO neutral year
Most PNW basins have land surface tendency for being on dry side by 3-10 percent: exceptions: south edge of Snake R. basin, also BC
The parts of the region that receive higher rainfall (west of the Cascades) are more likely to recover from moisture deficits from last year.
Questions?
website:
www.hydro.washington.edu / forecast / westwide /
Seasonal Climate Prediction
e.g., precipitation
CPC Temperature Outlook
CPC Precipitation Outlook
3/15 ESP fcst: WY2006 vs. WY1977 Precip, Temp
Snake River basin