MODEL RESPONSE SENSITIVITY TO WAVES, NONLINEAR ADVECTION, AND BOTTOM FRICTION Patrick C. Kerr 17 th ADCIRC WORKSHOP April 29-30, Patrick Corbitt Kerr, P.E. University of Notre Dame
Part I Wave Bottom Friction Patrick C. Kerr 17 th ADCIRC WORKSHOP April 29-30, 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?
Wave Bottom Friction Friction Formulations 3 Patrick C. Kerr 17 th ADCIRC WORKSHOP April 29-30, Variable Bottom Material JONSWAP Formulation Bottom Friction in SWAN Recommend by Literature Muddy Bottom? Madsen Formulation Based on Manning’s n
A CB
D GE
H JI
Wave Bottom Friction Summary of Findings 7 Patrick C. Kerr 17 th ADCIRC WORKSHOP April 29-30, 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.
Part II Component Contributions Patrick C. Kerr 17 th ADCIRC WORKSHOP April 29-30, 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?
Contribution of Non-Linear Advection OVERALL TEMPORAL
Contribution of Wave Radiation Stress OVERALL TEMPORAL
Component Contributions Scaling Ike at 5 Locations 11 Patrick C. Kerr 17 th ADCIRC WORKSHOP April 29-30, Local Non-Linear Advection Coriolis Surface Gradient Atmospheric Pressure Tidal Potential Gradient Wind Stress Wave Radiation Stress Gradient Bottom Friction Diffusion (Momentum) Terms
LOCATION 1 Significant Terms: Pressure Surface Local Coriolis
LOCATION 2 Major Terms: Local Coriolis Pressure Surface Moderate Terms: Advection Wind
LOCATION 3 Significant Terms: Surface Wind Bottom Coriolis Local Advection
LOCATION 4 Significant Terms: Surface Wind Advection Wave Bottom Coriolis
LOCATION 5 Significant Terms: Bottom Surface Wind
Component Contributions Summary of Findings 17 Patrick C. Kerr 17 th ADCIRC WORKSHOP April 29-30, 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 cm 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.
QUESTIONS 18 Patrick C. Kerr 17 th ADCIRC WORKSHOP April 29-30,