Semester of Graduation

Spring 2020

Department

Oceanography and Coastal Sciences

Document Type

Thesis

Abstract

The coastal wetlands of Louisiana constitute ~40% of the wetlands in the United States. However, it suffers from 80% of the wetland losses in the whole country. In shallow coastal and estuarine environments, bed shear stresses related to wind waves contributes substantially to the edge erosion in the northern Gulf of Mexico (NGoM). Therefore, wave simulations in shallow estuarine areas are of great importance.

There are several challenges in simulating waves nearshore, especially over the shallow and nearly horizontal sea beds typical of the NGoM continental shelf and adjacent complex geometry estuaries: determination of the appropriate wind forcing dataset to drive the wave model; underestimation of wave heights due to the application of default depth-induced breaking formulae under finite-depth wave growth condition and neglecting wave-current interaction in areas with a strong tidal current that causes the model simulation deviate from real conditions.

This study aims to evaluate wave dynamics over the shallow inlet/estuarine environment of the NGoM using a numerical modelling approach. The third-generation SWAN wave model employing an unstructured mesh is constructed to simulate wind-wave generation, decay, and transformation over the inner continental shelf and the Barataria Bay. A detailed sensitivity analysis is conducted in which various options for input wind sources, wave generation and dissipation, depth induced wave breaking, and bed friction are tested. The objective is to find the best parameter combination to improve predictions in integrated wave parameters, such as significant wave height and peak wave period. Verifying against available field measurements in the NGoM, the model results are found to be in fair agreement with the observations.

Committee Chair

Huang, Haosheng

DOI

10.31390/gradschool_theses.5059

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