HYDROLOGIC ENSEMBLE FORECASTING Dong-Jun Seo 1, Sunghee Kim 1, Hossein Sadeghi 1, Frank Bell 2, Andrew Philpott 2 1 Dept. of Civil Eng., The University of Texas at Arlington, Arlington, TX 2 West Gulf River Forecast Center, NOAA/NWS, Fort Worth, TX 1
What is ensemble forecasting? 2
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Why ensemble forecasting? Quantify forecast uncertainty Improve forecast accuracy Extend forecast lead time Weather and climate forecasts are noisy; the only practical way to make use of their skill is via ensemble forecasting Improve cost-effectiveness of investment In 2006, the National Research Council recommended that the NWS produce uncertaintyquantified products, expand verification and make information easily available to all users in near real time. June 5, 2015 Sustainable Urban Water Workshop, Arlington, TX 4
Provide an estimate of the forecast (i.e. predictive) uncertainty Current short-range river forecasts are single-valued RFCs have limited capability to provide what-if scenarios Customers demand uncertainty information for decision support Instead, run ensembles of inputs through river models to generate hydrologic forecasts Apply ensemble information to quantify forecast uncertainty and produce a full range of possible hydrologic scenarios 5
Hydrologic Ensemble Forecast Service (HEFS) Demargne et al. (2014) 6
Meteorological Ensemble Forecast Processor (MEFP) WPC: Weather Prediction Center RFC: River Forecast Center GEFS: Global Ensemble Forecast System CFSv2: Climate Forecast System version 2 June 5, 2015 Sustainable Urban Water Workshop, Arlington, TX 7
Study area Upper Trinity River Basin 8
0.7 0.6 0.5 BSS for RFC QPF & climatology All seasons Brier Skill Score 0.4 0.3 0.2 0.1 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15-0.1 Forecast lead time (days) 0.0 (Pr=0.25) 0.11243 (Pr=0.75) 4.8132 (Pr=0.9) 13.60888 (Pr=0.95) 39.57512 (Pr=0.99) 9
0.7 0.6 BSS for RFC QPF & GEFS Brier Skill Score 0.5 0.4 0.3 All seasons 0.2 0.1 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15-0.1 Forecast lead time (days) 0 (Pr = 0.25) 0.11243 (Pr = 0.75) 4.8132 (Pr = 0.9) 13.6088 (Pr = 0.95) 39.57512 (Pr = 0.99) 10
From Brown et al. 2014 June 5, 2015 Sustainable Urban Water Workshop, Arlington, TX 11
From Brown et al. 2014 June 5, 2015 Sustainable Urban Water Workshop, Arlington, TX 12
From Brown et al. 2014 June 5, 2015 Sustainable Urban Water Workshop, Arlington, TX 13
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Partners Description Contact One of the largest raw water suppliers in the state of Texas. Provides water to more than 1.7 million people in the North Central Texas area. Serves more than 30 wholesale customers including the cities of Fort Worth, Arlington, Mansfield and the Trinity River Authority. Operations span an 11-county area and include maintenance of dams at the Water District s four reservoirs as well as the more than 150 miles of pipeline used for water transport. Tarrant Regional Water District (TRWD) The Trinity River Authority of Texas (TRA) North Central Texas Council of Government (NCTCOG) Key partners and collaborators A conservation and reclamation district providing water and wastewater treatment, along with recreation and reservoir facilities, for municipalities within the nearly 18,000-squaremile Trinity River basin. Also maintains a master plan for basin-wide development, and serves as a conduit for taxexempt financing for municipal projects and as a local sponsor for federal water projects. Assists local governments in planning for common needs, cooperating for mutual benefit, and coordinating for sound regional development. Serves a 16-county region of North Central Texas (over 6.5 million residents), which is centered around the two urban centers of Dallas and Fort Worth. NCTCOG has over 230 member governments including 16 counties, numerous cities, school districts, and special districts. Hydrologic ensemble forecasting Laura Blaylock (Laura.Blaylock@t rwd.com), hydrologist Glenn Clingenpeel (ClingenpeelG@tri nityra.org), Senior Manager, Planning & Environ. Mgt. Div. Jack Tidwell (JTidwell@nctcog. org), Manager of Environment & Development NOAA/NWS/West Gulf River Forecast Center in Fort Worth, TX 15
Tarrant Regional Water District Water Supply System 16
Lake Bridgeport Eagle Mtn. Lake Richland- Chambers Cedar Creek Lake Arlington * Benbrook Lake * Lake Worth * Primary Inflow West Fork of the Trinity River West Fork of the Trinity River, Lake Bridgeport Richland Creek, Chambers Creek Primary Outflow Eagle Mtn. Lake Lake Worth Richland Creek Catchment Owner Area (mi 2 ) 1,111 TRWD 859 (excl. that TRWD of Lake Bridgeport) 1,957 TRWD Cedar Creek Trinity River 1,007 TRWD 143 City of Arlington 429 US Army Corps of Engineers 82 (excl. that of City of Fort Eagle Mtn. Worth Lake) 17
Water supply, drought - NOAA/NWS Hydrologic Ensemble Forecast Service (HEFS) Hydrologic ensemble forecasting From Pyke (2013) From NWS (2014) 18
THANK YOU For more information, please contact: djseo@uta.edu 19