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Current ?Official Forecasts". Methodologies currently in use for ?Official Forecasts" are statistical: Multiple Linear Regression Principle Component AnalysisMonthly, Seasonal Volume, Residual VolumeEarly Season forecasts (Nov 1, Dec 1)Associated forecast errors (cross-validation standard er
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1. Water Supply Forecasts Nancy Stephan
Bonneville Power Administration
RMJOC Climate Change Data Set Workshop
June 9, 2009
2. Current “Official Forecasts” Methodologies currently in use for “Official Forecasts” are statistical:
Multiple Linear Regression
Principle Component Analysis
Monthly, Seasonal Volume, Residual Volume
Early Season forecasts (Nov 1, Dec 1)
Associated forecast errors (cross-validation standard error)
3. Predictors used to make Water Supply Forecasts Fall/Winter precipitation
Snowpack (SWE)
Spring precipitation
Antecedent runoff
Temperature (used in BCH forecast)
Climate Indices: Southern Oscillation Index Multivariate ENSO Index
4. Water Supply Forecasts
6. What are the volumes used for? To-date – July: Calculate Treaty projects power draft rights (VECC)
April – Aug (Jul): Flood Control Determine Refill Curves Bi-Op, Fish operations
May – Jul (Sep): Refill Curve for HGH
7. Forecast Errors The Dalles:
January – July = 104 maf
Jan1 – SE 16.6 maf (95% confidence 27.3 maf)
Feb1 – SE 12.4 maf (95% confidence 20.1 maf)
Mar1 – SE 9.4 maf (95% confidence 15.5 maf)
Apr1 – SE 7.1 maf (95% confidence 11.7 maf)