Date of Award

Summer 8-2021

Degree Type

Masters Thesis

Degree Name

Master of Science (MS)

School

Ocean Science and Engineering

Committee Chair

Jerry D. Wiggert

Committee Chair School

Ocean Science and Engineering

Committee Member 2

Stephan Howden

Committee Member 2 School

Ocean Science and Engineering

Committee Member 3

Mustafa Kemal Cambazoglu

Committee Member 3 School

Ocean Science and Engineering

Abstract

A small yet notable hypoxic event manifests east of the Birdfoot Delta in the Mississippi Sound and Bight (MSAB). The shallow shelf environment of the MSAB is affected by a host of complex physical interactions and separating the influences of each process is difficult to accomplish with in-situ data alone. A physical model using high-resolution atmospheric forcing has been developed which provides insights into the physical interactions in this coastal marine system heavily influenced by freshwater plumes and diurnal wind forcing. Twin experiments using a high temporal (hourly) and spatial (0.01 deg) resolution meteorological analysis product, along with a temporally filtered version, have been performed to investigate the influence of the diurnal sea breeze on the flushing of estuarine waters onto the shelf.

Results from these numerical experiments have provided a detailed perspective on flushing times and the impacts on the appearance of the poorly understood hypoxic event in the MSAB. The higher resolution atmospheric forcing has demonstrable impacts on the hydrodynamics of the MSAB. The twin experiments highlight the influence of diurnal sea-breeze forcing, which impacts bottom water flushing times in areas known to be hypoxia hotspots. The experiments show that the probability of hypoxia formation decreases when diurnal energy is present due to its impact on water column stability. Finally, the wind fields used to conduct the twin experiments are combined to create a seasonal evolution of the sea-land breeze circulation within the MSAB that was not previously realized using the in-situ data alone.

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