Embed Size (px)
DESCRIPTION
Review of 2008 April through July Period Forecast for 4 Selected Basins Determine what verification statistics say about our forecasting efforts by: Determine which tools might work better than others Look for patterns that indicate better performance or indicate a wasted effort - PowerPoint PPT Presentation
Citation preview
Great Basin Verification Task 2008Great Basin Verification Task 2008
Increased VariabilityReview of 2008 April through July Period Forecast for 4 Selected Basins
Determine what verification statistics say about our forecasting efforts by:
Determine which tools might work better than others
Look for patterns that indicate better performance or indicate a wasted effort
Look at patterns of variability in data and forecasts.
Look for Patterns in both the Observed and Forecasts Records
Big Cottonwood Creek Near Salt Lake City, UTBig Cottonwood Creek Near Salt Lake City, UTHistorical Stream Flow and ForecastsHistorical Stream Flow and Forecasts
Increased Variability?1899-2008
1979-2008
Big Cottonwood Creek Near Salt Lake City, UTBig Cottonwood Creek Near Salt Lake City, UTScatter Plot of Stream Flow ForecastsScatter Plot of Stream Flow Forecasts
Over Forecasting Lows
Under Forecasting Highs
1991-2008
Big Cottonwood Creek Near Salt Lake City, UTBig Cottonwood Creek Near Salt Lake City, UTHistorical Stream Flow and Forecasts Scatter Plots PORHistorical Stream Flow and Forecasts Scatter Plots POR
1979-2008
1979-2008
1979-2008
Coordinated Forecasts are Consitently Too High
Big Cottonwood Creek Near Salt Lake City, UTBig Cottonwood Creek Near Salt Lake City, UTRank HistogramRank Histogram
3 times the calculated probability
Big Cottonwood Creek Near Salt Lake City, UTBig Cottonwood Creek Near Salt Lake City, UTMean Absolute Error Lead TimeMean Absolute Error Lead Time
14%
26%
6%
Bear River – Near Utah, Wyoming State LineBear River – Near Utah, Wyoming State LineHistorical Stream FlowHistorical Stream Flow
1992-2008
1942-2008
1992-2008
Bear River – Near Utah, Wyoming State Line Bear River – Near Utah, Wyoming State Line Scatter Plot of Stream Flow vs Forecast ValuesScatter Plot of Stream Flow vs Forecast Values
1992-2008
2001-2008
Bear River – Near Utah, Wyoming State Line Bear River – Near Utah, Wyoming State Line
1942-20081986
1977
1992-2008
Bear River – Near Utah, Wyoming State LineBear River – Near Utah, Wyoming State LineSkill Score – 2 periodsSkill Score – 2 periods
1992-2000
2001-2008
Bear River – Near Utah, Wyoming State Line Bear River – Near Utah, Wyoming State Line Rank HistogramRank Histogram
2001-2008
1992-2000
Logan River Near Logan, UtahLogan River Near Logan, UtahHistorical Stream Flow & ForecastsHistorical Stream Flow & Forecasts
1983-2007
1900-2008
1958-19702000
1986
Logan River Near Logan, UtahLogan River Near Logan, UtahHistorical Stream Flow & ForecastsHistorical Stream Flow & Forecasts
1990-2008: Forecast POR
2001-2008: SWS seems to be over forecasting.
Logan River Near Logan, UtahLogan River Near Logan, UtahScatter Plot of ForecastsScatter Plot of Forecasts
1991-2008
1979-2008
Split Distribution of Values
Distribution move evenly space going back to 1971
Logan River Near Logan, UtahLogan River Near Logan, UtahRank Histogram 1991-2008Rank Histogram 1991-2008
1991-2008
Under Forecasting moreFrequently in the
Region of the 10% ExceedanceProbability
Over Forecasting LessFrequently in the 90%
Exceedance Region than in the 10% Region.
Logan River Near Logan, UtahLogan River Near Logan, UtahRank Histogram 2001-2008Rank Histogram 2001-2008
Better than Predicted forecasting of low flows
Worse than PredictedValues when Forecasting High
Flows.
2001-2008
Improved StatsUsing the most recent years
Logan River Near Logan, UtahLogan River Near Logan, UtahPOD Above / POD Below Threshold for PORPOD Above / POD Below Threshold for POR
Consistently Lower POD “Above Threshold” - No Matter the Month
Good POD ofVolumes Below
Threshold, except SWS in Jan, Feb.
Logan River Near Logan, UtahLogan River Near Logan, UtahMean Absolute Error – Lead TimeMean Absolute Error – Lead Time
44kaf
28kaf25kaf
23kaf 18kaf13kaf
Weber at Oakley, UtahWeber at Oakley, UtahHistorical Stream Flow and ForecastsHistorical Stream Flow and Forecasts
1990-2008
7 of Top 10 A-J Flows Occurred Before 1922
Weber at Oakley, UtahWeber at Oakley, UtahHistorical Forecast PlotsHistorical Forecast Plots
2001-2008 ~ Using New Averages SeemsTo have Improved our Forecasting Efforts
1990-2000 ~ Prior to ESP and New AveragesUnder Forecasting was a Consistent Problem
Weber at Oakley, UtahWeber at Oakley, UtahScatter Plot of Forecast vs ObservedScatter Plot of Forecast vs Observed
1990-2008, no forecast were made prior to 1990
Clearly Under Forecasting the High Years
Weber at Oakley, UtahWeber at Oakley, UtahRank HistogramRank Histogram
Weber at Oakley, UtahWeber at Oakley, UtahPOD Above and Below ThresholdPOD Above and Below Threshold
Weber at Oakley, UtahWeber at Oakley, UtahMean Absolute Error Lead TimeMean Absolute Error Lead Time
38kaf
9kaf
ConclusionsConclusionsGreat Basin Verification Task 2008Great Basin Verification Task 2008
Increased Variability
Findings indicate we detect low flows better than high flows with current and often over forecast the 10% exceedance values.
Some Statistics Suggest that SWS often forecast too high in comparison to NWS, NRCS and ESP Forecasts
That coordinated forecast numbers are skewed and result in over forecasting.
That many of the data sets from 1991-2008 have a binary split indicating that more extremes have occurred in observed flows during the last 20 years.
MOST IMPORTANTLY
That our forecasting efforts have improved since 2001.
![06008.01-Task 2-Documents and Data Review 1031061].01-ta… · OCTOBER 2006 EAA BASIN DATA EVALUATION (PHASE I) TASK 2: DOCUMENTS AND DATA REVIEW, ST061287-WO01 06008.01-Task 2-Documents](https://img.pdfslide.us/doc/110x75/5f0f47347e708231d4435de6/0600801-task-2-documents-and-data-review-103106-101-ta-october-2006-eaa-basin.jpg)
