Flood Forecasting - Peter Gibbs

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Presentation given by Peter Gibbs, Met Office and BBC broadcast meteorologist, as part of the EDINA Geoforum 2014 event on Thursday 19th June 2014 at the Informatics Forum, University of Edinburgh.

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Flood Forecasting - Peter Gibbs

  1. 1. All images courtesy of the Met Office / Environment Agency unless stated otherwise
  2. 2. Summer Floods 2007 All images courtesy of the Met Office / Environment Agency unless stated otherwise
  3. 3. (6) The Environment Agency and the Met Office should work together, through a joint centre, to improve their technical capability to forecast, model and warn against all sources of flooding (34) The Met Office and the Environment Agency should issue warnings against a lower threshold of probability to increase preparation lead times for emergency responders. Pitt Review Recommendations Photograph: Getty Images
  4. 4. Difficult science
  5. 5. Difficult science
  6. 6. Surface observations
  7. 7. Upper air
  8. 8. Aircraft Over 130,000 observations per day
  9. 9. Weather satellites
  10. 10. The Unified Model And now, the forecast
  11. 11. GM (40 Km) UK4 (4 Km) Model resolution
  12. 12. Model resolution
  13. 13. Model resolution
  14. 14. Model resolution
  15. 15. • soil type • Soil moisture content • vegetation type • sea surface temperature • proportion of sea-ice cover • sea-ice thickness • sea surface currents Not just weather!
  16. 16. Day 1 Chaos in action
  17. 17. Day 3 Chaos in action
  18. 18. Day 7 Chaos in action
  19. 19. Ensemble forecasting
  20. 20. Ensemble forecasting
  21. 21. Summer Floods 2007
  22. 22. Ensemble forecasts Grid to Grid Modelling Impact assessment Improved guidance Our Science
  23. 23. Fluvial (river) flooding © Vagner Vidal/INS News Agency
  24. 24. Pluvial (flash) flooding Image courtesy of the BBC
  25. 25. Coastal flooding Photograph: Danny Lawson/PA
  26. 26. Groundwater flooding Image courtesy of the BBC
  27. 27. Gridded input data for: Rain gauge / radar; Nowcasts; (STEPS)NWP Cumbria 2009
  28. 28. G2G flow (cumecs)
  29. 29.  Forecast flows from each grid cell are converted to return period flows (QT grids) G2G flows presented as return periods
  30. 30. G2G return periods - National Overview  Final steps are to summarise this information as a ‘maximum status’ of return period flow exceedance for each county over a chosen time interval (e.g. 24 hours)  And then link this in with risk levels on FGS
  31. 31. Cumbria 2009, FGS leading up to the event Nov 19-20
  32. 32. Lowestoft (~5 day forecast) 1. Assessing the flood risk
  33. 33. Lowestoft (~4 day forecast)
  34. 34. Lowestoft (~2 day forecast)
  35. 35. 2. Communicating the flood risk - Risk Timeline  Thursday 28 Nov CHM briefed Strategic Manager  Saturday 30 Nov Escalation starts with ‘what if’ scenarios  Sunday 1 Dec – Green, but referenced in FGS & briefings  Monday 2 Dec - Yellow  Tuesday 3 Dec - Yellow  Wednesday 4 Dec - Amber  Thursday 5 Dec – Amber (AM) then Red  Friday 6 Dec – Red (AM) then Amber  Saturday 7 Dec - Yellow  Sunday 8 Dec - Yellow
  36. 36. Example of possible impact assessment output Impact Score None Minimal Minor Significant Severe Modelling is at 1 km grid squares, but output is designed to be used at lower resolution due to uncertainties in the forecasts and to input into the Flood Guidance Statement.
  37. 37. Expertise in Hydrometeorology: • Holistic approach to flood forecasting • New services for surface water and public • A framework for up-skilling in the industry • Greater trust by raising industry standards and improving communications • Efficiencies and value for money Our Skills

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