1. MODEL RESPONSE SENSITIVITY TO WAVES, NONLINEAR ADVECTION, AND BOTTOM FRICTION Patrick C. Kerr 17 th ADCIRC WORKSHOP April 29-30, 2013 1 Patrick Corbitt Kerr, P.E. JJ Westerink, RC Martyr, ME Hope University of Notre Dame

2. usSEABED: GoM Offshore Surficial Sediment Database 2 Patrick C. Kerr 17 th ADCIRC WORKSHOP April 29-30, 2013 2

3. 3 TIDES Ike (2008) CURRENT ENERGY

4. Effect of Chezy-Type Bottom Friction 4 Patrick C. Kerr 17 th ADCIRC WORKSHOP April 29-30, 2013 4

5. Part I Wave Bottom Friction Patrick C. Kerr 17 th ADCIRC WORKSHOP April 29-30, 2013 5 If circulation models are sensitive to bottom friction on the Louisiana-Texas shelf, what is the sensitivity of wave models to bottom friction formulation in that region?

6. Wave Bottom Friction Friction Formulations 6 Patrick C. Kerr 17 th ADCIRC WORKSHOP April 29-30, 2013 6 Variable Bottom Material JONSWAP Formulation Bottom Friction in SWAN Recommend by Literature Muddy Bottom? Madsen Formulation Based on Manning’s n

7. A CB

8. D GE

9. H JI

10. Wave Bottom Friction Summary of Findings 10 Patrick C. Kerr 17 th ADCIRC WORKSHOP April 29-30, 2013 10 Model Response Sensitivity to Wave Bottom Friction Formulation – Madsen and JONSWAP formulations are both adequate – The JONSWAP friction coefficient is sensitive to bottom type, therefore a C jfon =0.019m 2 s -3 should be used for the muddy LATEX shelf.

11. Part II Component Contributions Patrick C. Kerr 17 th ADCIRC WORKSHOP April 29-30, 2013 11 What is the spatial and temporal contributions of wave radiation stress and non-linear advection terms in a hurricane storm surge model and how do these processes compare with the other components of the shallow water equations?

12. Contribution of Non-Linear Advection OVERALL TEMPORAL

13. Contribution of Wave Radiation Stress OVERALL TEMPORAL

14. Component Contributions Scaling Ike at 5 Locations 14 Patrick C. Kerr 17 th ADCIRC WORKSHOP April 29-30, 2013 14 Local Non-Linear Advection Coriolis Surface Gradient Atmospheric Pressure Tidal Potential Gradient Wind Stress Wave Radiation Stress Gradient Bottom Friction Diffusion (Momentum) Terms

15. LOCATION 1 Significant Terms: Pressure Surface Local Coriolis

16. LOCATION 2 Major Terms: Local Coriolis Pressure Surface Moderate Terms: Advection Wind

17. LOCATION 3 Significant Terms: Surface Wind Bottom Coriolis Local Advection

18. LOCATION 4 Significant Terms: Surface Wind Advection Wave Bottom Coriolis

19. LOCATION 5 Significant Terms: Bottom Surface Wind

20. Component Contributions Summary of Findings 20 Patrick C. Kerr 17 th ADCIRC WORKSHOP April 29-30, 2013 20 Galveston, TX Component Contributions for Hurricane Ike (2008) – Non-linear advection captures 10-20cm of geostrophic setup and increases resonant waves by 30-40cm. – Wave radiation stress adds 20- 40cm to maximum water levels and is responsible for an earlier rise in water levels. – Bottom Friction and Coriolis were significant components in the development of Ike’s Forerunner.

21. QUESTIONS 21 Patrick C. Kerr 17 th ADCIRC WORKSHOP April 29-30, 2013 21