Recap of Water Year 2009 Hydrologic Forecast and Forecasts for Water Year 2010 Francisco Munoz-Arriola Alan F. Hamlet Shraddhanand Shukla Dennis P. Lettenmaier •JISAO/CSES Climate Impacts Group Dept. of Civil and Environmental Engineering University of Washington
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Recap of Water Year 2009 Hydrologic Forecast and Forecasts for Water Year 2010 Francisco Munoz-Arriola Alan F. Hamlet Shraddhanand Shukla Dennis P. Lettenmaier.
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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)
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