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EST Approach for Extratropical Storms

EST Approach for Extratropical Storms. Empirical Simulation Technique. Preferred method for calculating return period elevations for extratropical storms Based on a bootstrap resampling-with-replacement and parameter interpolation scheme

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EST Approach for Extratropical Storms

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  1. EST Approach for Extratropical Storms

  2. Empirical Simulation Technique Preferred method for calculating return period elevations for extratropical storms Based on a bootstrap resampling-with-replacement and parameter interpolation scheme Multiple life cycle simulations of non-deterministic events Method effectively expands smaller sample populations

  3. SWEL Stations • JPM/EST • 2000 ft grid • 74,719 pts • 68% land • 32% water

  4. EST Input Parameters • Stations • Number of input parameters = 2 • Tide • Surge • Event Frequency = (events/years) • Response Parameter Threshold • Length of simulations • Simply to frequency of interest • Number of simulations • Sensitivity • Number of response parameter = 1 • Combined tide & surge

  5. Response Parameter Threshold • Allows user to specify minimum response value (global parameter) • MHHW • Calculated for all mesh nodes, translated to grid • Zonal division

  6. Treatment of Tides Ext. STORM Spring Tie Neap Tide Spring Tide Neap Tide Lunar spring-neap tidal cycle at Cape Hatteras Pier, NC.

  7. Reconstruction of Tides • Each Station and Storm • Historical Tidal Signal • One month period • Diurnal High Tide • Assumed to occur during the peak elevation of the storm event

  8. CDF Related to Tidal Curve Probability density function representing diurnal high tide elevation range over the lunar tidal cycle. Tidal elevation bins as related to the sampled tidal signal.

  9. Input and Response Vectors • Input Vectors • I1. Tidal stage, representing potential tidal stage levels over the lunar cycle • I2. Peak surge elevation, as simulated by the ADCIRC for each event • Response Vector • R1. Combined tide and surge elevation

  10. Probabilities • Literature shows…(Scheffner and Mark 1997, Scheffner et al 1999a, Scheffner et al 1999b, Scheffner and Carson 2001, Scheffner and Mack 2004). • Events assigned equal probability on resample • Equal probability that the event could occur at any of the five tidal stages

  11. Input • Each event resampled at 5 tidal elevations March 1962 Northeaster, Surge elevation of 0.65 m

  12. Output

  13. Combined Return Period • JPM tropical and EST extratropical frequency analyses are combined for the final return period elevations:

  14. Questions?

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