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Bayesian Estimation of Nowcast and Forecast Flow

Bayesian Estimation of Nowcast and Forecast Flow. NSF Group Meeting Update Carolyn Krekeler 11/12/2010. Recent Developments. Implemented Nowcasting and Forecasting in Bayesian Network with message passing

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Bayesian Estimation of Nowcast and Forecast Flow

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  1. Bayesian Estimation of Nowcast and Forecast Flow NSF Group Meeting Update Carolyn Krekeler 11/12/2010

  2. Recent Developments • Implemented Nowcasting and Forecasting in Bayesian Network with message passing • Reduced number of spatial nodes so relationships between adjacent nodes contain more information • Investigated addition of point source rain data and Nexrad data, separately

  3. RC RU . . . . . . Nowcast Day Forecast Day Network and Features • Training Data • WAM Predictions, 1/1/1990 – 12/31/2008, ft3/s • NCDC Rain at Starke (confined) and High Springs (unconfined) accumulated over 5 day periods, 10/1/2000 – 12/31/2008, mm

  4. Correlation Issue • Flow is highly correlated with itself both spatially and temporally • This does not allow for information gain from rain data • Solution: Subsample spatial nodes so flow upstream is not as similar to flow downstream

  5. Subsampled Spatial Locations • Chose 6 spatial nodes along stream rather than 23

  6. Results (Nowcast and 3 Day Forecast) Node 1 Nowcast(evidence) • NSE: 1.00 • PBIAS: 0.00% • RSR: 0.00 • Node 1 Forecast • NSE: 0.38 • PBAIS: 15.18% • RSR: 0.79

  7. Results (Nowcast and 3 Day Forecast) Node 2 Nowcast • NSE: 0.93 • PBIAS: 15.70% • RSR: 0.28 • Node 2 Forecast • NSE: 0.36 • PBAIS: 26.78% • RSR: 0.80

  8. Results (Nowcast and 3 Day Forecast) Node 3 Nowcast • NSE: 0.81 • PBIAS: 22.53% • RSR: 0.43 • Node 3 Forecast • NSE: 0.33 • PBAIS: 29.01% • RSR: 0.82

  9. Results (Nowcast and 3 Day Forecast) Node 4 Nowcast • NSE: 0.67 • PBIAS: 26.41% • RSR: 0.57 • Node 4 Forecast • NSE: 0.27 • PBAIS: 24.89% • RSR: 0.85

  10. Results (Nowcast and 3 Day Forecast) Node 5 Nowcast (evidence) • NSE: 1.00 • PBIAS: 0.00% • RSR: 0.00 • Node 5 Forecast • NSE: 0.55 • PBAIS: -10.51% • RSR: 0.67

  11. Results (Nowcast and 3 Day Forecast) Node 6 Nowcast • NSE: 0.97 • PBIAS: 2.55% • RSR: 0.18 • Node 6 Forecast • NSE: 0.69 • PBAIS: 1.65% • RSR: 0.56

  12. R R R R R R Nowcast Day Forecast Day Topology with Nexrad Data • Summed Nexrad daily rain over contributing area for each node • Accumulated summed Nexrad over 5 day period, as with point rain data • Rain over last 5 days at the nowcast day used as evidence for forecasting flow

  13. Nexrad Data Issue • Forecast flow shows similar issue as with pre-subsampled flow • Flow highly resembles Nexrad rain, with limited contribution from nowcast flow • Possible Solutions: • Subsample Network more to weaken relationship between rain and nowcast flow • Use fewer rain classes • Increase smoothing factor (kernel overlap) when forming pdfs of rain

  14. Nexrad-Flow Correlation • Can see that Forecast flow is mainly determined by Nexrad Rain data

  15. Nexrad Analysis • To get somewhat meaningful forecast results, used class labels from nowcast days (not affected by rain), rather than those generated from clustering current flow, current rain, and future flow together • Still get noisy forecast, but it at least follows the trend of flow rather than rain • Will continue to use point rain data instead of Nexrad

  16. Results with Nexrad (Nowcast and 3 Day Forecast) Node 3 Nowcast • NSE: 0.89 • PBIAS: 17.24% • RSR: 0.33 • Node 3 Forecast • NSE: 0.35 • PBAIS: 14.89% • RSR: 0.81

  17. The End

  18. Point Source Rain • Confined (Starke) • Unconfined (High Springs)

  19. Nexrad Rain • Rain Node 1 • Rain Node 2

  20. Nexrad Rain • Rain Node 3 • Rain Node 4

  21. Nexrad Rain • Rain Node 5 • Rain Node 6

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