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. University of Notre Dame

2. Part I Wave Bottom Friction Patrick C. Kerr 17 th ADCIRC WORKSHOP April 29-30, 2013 2 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?

3. Wave Bottom Friction Friction Formulations 3 Patrick C. Kerr 17 th ADCIRC WORKSHOP April 29-30, 2013 3 Variable Bottom Material JONSWAP Formulation Bottom Friction in SWAN Recommend by Literature Muddy Bottom? Madsen Formulation Based on Manning’s n

4. A CB

5. D GE

6. H JI

7. Wave Bottom Friction Summary of Findings 7 Patrick C. Kerr 17 th ADCIRC WORKSHOP April 29-30, 2013 7 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.

8. Part II Component Contributions Patrick C. Kerr 17 th ADCIRC WORKSHOP April 29-30, 2013 8 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?

9. Contribution of Non-Linear Advection OVERALL TEMPORAL

10. Contribution of Wave Radiation Stress OVERALL TEMPORAL

11. Component Contributions Scaling Ike at 5 Locations 11 Patrick C. Kerr 17 th ADCIRC WORKSHOP April 29-30, 2013 11 Local Non-Linear Advection Coriolis Surface Gradient Atmospheric Pressure Tidal Potential Gradient Wind Stress Wave Radiation Stress Gradient Bottom Friction Diffusion (Momentum) Terms

12. LOCATION 1 Significant Terms: Pressure Surface Local Coriolis

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

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

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

16. LOCATION 5 Significant Terms: Bottom Surface Wind

17. Component Contributions Summary of Findings 17 Patrick C. Kerr 17 th ADCIRC WORKSHOP April 29-30, 2013 17 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.

18. QUESTIONS 18 Patrick C. Kerr 17 th ADCIRC WORKSHOP April 29-30, 2013 18