Date of Award
8-2026
Degree Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
School
Ocean Science and Engineering
Committee Chair
Dr. Jerry Wiggert
Committee Chair School
Ocean Science and Engineering
Committee Member 2
Dr. Kemal Cambazoglu
Committee Member 2 School
Ocean Science and Engineering
Committee Member 3
Dr. Diana Bernstein
Committee Member 3 School
Ocean Science and Engineering
Committee Member 4
Dr. Brian Dzwonkowski
Committee Member 5
Dr. John Warner
Abstract
This dissertation seeks to understand riverine stressors in the complicated coastal system of the Mississippi Sound and Bight (MSB) and provide accurate real-time and historical model output for science-based guidance to resource managers and decision makers by developing a regional forecast system. The system, msbCOAWST, incorporates operational forecast model forcing and boundary conditions which assimilate quality controlled in-situ data sources, including National Water Model riverine discharge, High Resolution Rapid Refresh atmospheric parameters and Navy Coastal Ocean Model regional lateral boundary conditions. The model, validated against available in situ data for 2023 and 2024, exceeds both National Ocean Service and Regional Ocean Modeling System (ROMS) targets for temperature, water level meets the ROMS assessment target for RMSE, and salinity meets the ROMS assessment target for correlation coefficient. Two seasons in 2024 are examined to assess sensitivity of the model to forecast forcing and boundary conditions, March representing the spring freshet and synoptic events and August representing calmer summer weather and a strong sea land breeze.
Sensitivity assessment found the forecast experiment has lower correlations and higher root mean squared error with in situ data for all variables when compared to the hindcast experiment. Isolating individual forecast forcing and boundary conditions showed that forecast river forcing improved how the model predicted salinity and sea surface height trends, but decreased the accuracy of salinity prediction; forecast boundary conditions led to lowest correlations with sea surface height; forecast atmospheric forcing led to lower average correlations and higher average RMSE with ocean temperature.
An assessment of regions of freshwater influence, salinity and transport fluxes indicates a broad circulation pattern within the Sound that is a result of the combined influence of zonal winds, sea surface height gradients and the geomorphology of the MSB. The msbCOAWST historical and daily hindcast collection has 10+ years of realistic forcing and output data which can be used to assess regional and seasonal patterns in circulation, water quality, hypoxia, habitat suitability, ecosystem response and sediment transport. Daily modeling of physical processes in the MSB can be used to derive daily products and provide guidance for resource managers addressing public concerns.
ORCID ID
0000-0003-3995-0444
Copyright
Brandy Armstrong, 2026
Recommended Citation
Armstrong, Brandy, "Assessing Salinity, Temperature, and Sea Surface Height Sensitivity to Riverine Water, Boundary Conditions, and Atmospheric Forcing in a Northern Gulf of Mexico Forecast System" (2026). Dissertations. 2487.
https://aquila.usm.edu/dissertations/2487