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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 JISAO/CSES Climate Impacts Group Dept. of Civil and Environmental Engineering University of Washington. Outline.
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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 • JISAO/CSES Climate Impacts Group • Dept. of Civil and Environmental Engineering • University of Washington
Outline • 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
Potential Implications of ENSO Transition States WY 2008 WY 2009 European Centre for Medium-Range Weather Forecasts http://www.ecmwf.int/products/forecasts/d/charts/seasonal/forecast/seasonal_range_forecast/nino_plumes_public_s3/
ECMRWF ENSO anomaly 2009 0.2 -0.6
Ensemble Mean 1961-99 Climatological Mean 1961-99 Ensemble Members Climatological Extremes Validation Plot for 2009 Forecast (All Neutral ENSO composite) at Dalles 3.4 Range 2009 -0.6 to 0.2 Ensemble Mean N years Observations
Ensemble Mean 1961-99 Climatological Mean 1961-99 Ensemble Members Climatological Extremes Based on Dalles Climatology 1901-2005 All Years Ensemble Mean N years Observations
ECMRWF ENSO anomaly 2010 1.8 0.9 Forecast of September 2009 European Centre for Medium-Range Weather Forecasts http://www.ecmwf.int/products/forecasts/d/charts/seasonal/forecast/seasonal_range_forecast/nino_plumes_public_s3/
Potential Implications of ENSO Transition States WY 2008 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/
April-September Naturalized Flow for the Columbia River at The Dalles, OR from Historic Water Years vs January Nino 3.4 Anomalies. 1916-2002
The Mischievous Boy or “El Niño Travieso” visits the PNW NOAA, CFS Precipitation Forecast IRI-Multi-model Probability Precipitation Forecast Oct-Nov-Dec Dec-Jan-Feb
2008 January June January June 2009 SWE SM
SWE and SM for the 2008 and 2009 WY 2008 Simulated SWE SM Climatological 2009
USGS Streamflow current status Obtained from http://waterwatch.usgs.gov/
Climatological Mean 1915-2000 Ensemble Members Climatological Extremes Climatological Streamflows (1915-2000) All Years Ensemble Mean EN years
Initial Conditions (percentiles) SM Change in SM
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
Ensemble Mean 1961-99 Climatological Mean 1961-99 Ensemble Members Climatological Extremes Streamflow Forecast on Dalles 1961-1999 All Years Ensemble Mean EN years
Ensemble Mean 1961-99 Climatological Mean 1961-99 Ensemble Members Climatological Extremes Based on Dalles Climatology 1961-1999 ESPs 3.4 Range 2010 0.9 to 1.8 Ensemble Mean EN years
Streamflow Change Observation Sep 2009-May 2010 8.4% 12.2%
Summary • Neutral ENSO conditions showed good agreement with climatological and observed streamflows during the Fall-Winter seasons in WY 2009; streamflow forecast during Summer of 2009 was underestimated • Conspicuous warm phase of ENSO in addition to dry soil moisture increase the likelihood of below normal streamflows during the WY 2010 over the Columbia river basin • Dalles station summarizes the surface hydrology of the Columbia River basin showing streamflows 8 to 12% (on average) below climatological streamflows for the following 9 months.
Soil Moisture and Snow Water Anomalies Sep 2009 Oct 2008 Jan 2009 Jun 2009
SWE and SM February March April Simulated Climatological