JPM Model Results

1. JPM Model Results Peter J Vickery and Dhiraj Wadhera Applied Research Associates 8537 Six Forks Rd, Suite 600 Raleigh, NC, 27615 March 9 2011

2. Historic Storms

3. Cat 2 Hurricanes

4. Cat 3 and Higher Hurricanes

5. Simulation Methodology

6. Coastal Segments

7. Landfall Pressures

8. Mile Posts

9. Comparison of Pressures

10. Comparison of Translation Speed

11. Comparisons of Heading

12. 100,000 Year Simulation Results 57,000 storms in the storm set. 17,664 storms produce a surge greater than 1m somewhere in the region. 100,000 year simulation performed using ARA And a simple Holland wind field model with a surface wind factor of 0.884

13. 100,000 Year Simulation Results 57,000 storms in the storm set. 17,664 storms produce a surge greater than 1m somewhere in the region. 100,000 year simulation performed using ARA and a simple Holland wind field model with a surface wind factor of 0.884

14. Effect of Reduced Storm Set

15. Effect of Reduced Storm Set

16. “Landfall” regions

17. Processing of reduced storm set • Three classes of storms • 1) NC Landfall (8190/17664) • 2) By-pass (5760/17664) • 3) VA/DE/NJ Landfalls (3171/17664)

18. NC and By-pass Tracks

19. VA Tracks

20. Surge vs. Landfall Parameters

21. Surge vs. Landfall Parameters

22. Landfall Location

23. NC Heading Pressure Correlation

24. Surge vs. By-Pass Parameters

25. JPM/Stochastic Landfall Parameters

26. JPM/Stochastic Landfall Parameters

27. Region III Grid Points 675 coastal locations used to compare JPM SWEL results with the full stochastic set SWEL results. Total of 468 tracks used in model.

28. % Errors in 100 Year MRI SWL • Error = (JPM-Stochastic)/Stochastic • Mean Error = -0.8%

29. Errors in 100 Year MRI SWL (ft) • Error = JPM-Stochastic • Mean Error = 0.05 ft

30. % Errors in 500 Year MRI SWL • Error = (JPM-Stochastic)/Stochastic • Mean Error = 5.6%

31. Errors in 500 Year MRI SWL (ft) • Error = (JPM-Stochastic)/Stochastic • Mean Error = 0.7 ft

32. % Errors in 10 Year MRI SWL • Error = (JPM-Stochastic)/Stochastic • Mean Error = -34%

33. Errors in 10 Year MRI SWL (ft) • Error = JPM-Stochastic • Mean Error = -0.6 ft

34. JPM vs. Stochastic

35. JPM vs. Stochastic

36. JPM vs. Stochastic

37. JPM vs. Stochastic

38. Error in 100 Year MRI SWEL’s

39. Error in 500 Year MRI SWEL’s

40. Summary • Design level storm surge dominated by hurricanes with central pressure differences less than ~ 75 mbar (central pressure greater than 938 mbar). • Typical RMW ~ 50 km or greater • Highest surges produced by hurricanes making landfall along the VA/DE/NJ coast • Contribution of by-passing hurricanes to design level events is relatively small • 99% of JPM results are within +/- 1 ft of the stochastic model • 89% of JPM results are within +/- 6 inches of the stochastic model

41. Summary • JPM methodology underestimates 10 year MRI SWEL and overestimates the 500 MRI SWEL • Recommend using current storm set • Apply mean offset correction to 10 year and 500 year results

42. Summary of results for thesingle Holland b storm set

43. % Errors in 100 Year MRI SWL • Error = (JPM-Stochastic)/Stochastic • Mean Error = -1.4%

44. Errors in 100 Year MRI SWL (ft) • Error = JPM-Stochastic • Mean Error = -0.04 ft

45. % Errors in 500 Year MRI SWL • Error = (JPM-Stochastic)/Stochastic • Mean Error = 1.7%

46. Errors in 500 Year MRI SWL (ft) • Error = (JPM-Stochastic)/Stochastic • Mean Error = 0.3 ft

47. % Errors in 10 Year MRI SWL • Error = (JPM-Stochastic)/Stochastic • Mean Error = -45%

48. Errors in 10 Year MRI SWL (ft) • Error = JPM-Stochastic • Mean Error = -0.8 ft

49. JPM vs. Stochastic

50. JPM vs. Stochastic