Title page for ETD etd-06302009-161650


Type of Document Dissertation
Author Rego, Joao Lima
Author's Email Address jlimarego@gmail.com
URN etd-06302009-161650
Title Storm Surge Dynamics over Wide Continental Shelves: Numerical Experiments Using the Finite-Volume Coastal Ocean Model
Degree Doctor of Philosophy (Ph.D.)
Department Oceanography & Coastal Sciences
Advisory Committee
Advisor Name Title
Chunyan Li Committee Chair
Clinton S. Willson Committee Member
Dimitris E. Nikitopoulos Committee Member
Jaye E. Cable Committee Member
James Catallo Dean's Representative
Keywords
  • Storm Motion
  • Surge Dynamics
  • Numerical Modeling
  • Physical Oceanography
  • Storm Surge
  • Louisiana
  • Texas
  • Coastal Inundation
  • Flooding
  • Numerical Modeling
  • Nonlinear interaction
  • Hurricane
Date of Defense 2009-06-16
Availability unrestricted
Abstract
Storm surge is an abnormal rise of the sea surface caused by atmospheric forcing, including the wind stress and atmospheric pressure associated with extra-tropical and tropical cyclones. Hurricanes and typhoons have a great impact on coastal regions, and can cause severe loss of lives and great damages. A systematic investigation of storm surge impact to the coasts of Louisiana and Texas, where the continental shelf reaches up to 200 km in width, is conducted

here using the hydrodynamics Finite-Volume Coastal Ocean Model, FVCOM (Chen et al., 2003). The model is applied to the northern Gulf of Mexico to simulate the storm surges caused by Hurricanes Rita (September 2005) and Ike (September 2008), and allows the resolution of the

flooding along the Louisiana and Texas coasts. Observations of inland flooding from USGS are

used to validate the model with satisfactory results. Various idealized scenarios are also

simulated using FVCOM, to gain insight into specific surge mechanisms. This study focuses on

the following topics: 1) The roles of shelf geometry and tides in a hurricane surge are explored in a set of experiments where the nonlinear interaction between tide and surge is investigated and found to be important, relative to the tidal amplitude; 2) The receding flow of Hurricane Rita’s surge waters back to the Gulf of Mexico and the different dynamics that produce the remarkably different flooding (~0.5 days) and return (>7 days) periods are explained; 3) The effect of the often overlooked forward speed of a hurricane, which was found to have an unexpected and significant impact on coastal surges, in that faster storms produce higher coastal peak surges but smaller overall inland flooding (vice-versa for slower storms); and 4) The importance of

Galveston Bay’s barrier islands on the propagation of Hurricane Ike’s surge, where results suggested that under a realistic erosion scenario for Bolivar Peninsula’s, the bay is exposed to dangerously high water levels almost as much as if the Peninsula was leveled to about Mean Sea Level, underlining the non-linear nature of this bay-barrier system.

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