Semester of Graduation

Spring 2025

Degree

Master of Science (MS)

Department

Oceanography and Coastal Sciences

Document Type

Thesis

Abstract

General circulation models (GCMs) lack the necessary spatial resolution to accurately depict the atmospheric and land surface processes that define the regional climate of any particular location. In contrast, regional climate models (RCMs) explicitly capture the interactions between the broad-scale weather patterns simulated by global models and the specific characteristics of the local terrain. In this work, the Weather Research and Forecasting (WRF) model is used for high-resolution (12-km) dynamical downscaling simulations for a historical period (1996-2005) and the future (2090-2099) forced by the NCAR's Community Earth System Model, version 1 (CESM1), for Louisiana and Mississippi. WRF performs more satisfactorily for temperature than precipitation when validated against atmospheric reanalysis and observations from meteorological stations. WRF shows improved performance in simulating temperature (r > 0.98, RMSE < 0.45 C°) and precipitation (r > 0.88, RMSE < 34 mm) during the transition seasons, such as fall and spring, compared to winter and summer. The lower correlation coefficient and higher RMSE observed for summer precipitation indicate the need for caution when interpreting future projections for this season. For all the meteorological seasons, the future RCM runs demonstrate significant projected increases in average and extreme temperatures overall, while precipitation changes were spatially variable and largely statistically insignificant. Despite less pronounced change in precipitation rates overall, fall season precipitation is expected to increase significantly near the Gulf of Mexico coast. Computing the differences between mean annual values of several extreme climate indices from the historical to the future simulation reveals interesting patterns of changes. The Gulf coast is projected to experience the largest increase in the frequency of extreme temperature days, while the northern climate divisions of Louisiana and central to northern Mississippi are expected to face a higher risk of prolonged extreme heat events. Contrasting trends of extreme precipitation intensity and frequency imply fewer but more intense precipitation events in the future. Analysis of the combined projected trends in extreme precipitation intensity, duration, and frequency indices suggests that, among all 19 climate divisions in the study area, the three northern climate divisions of Louisiana are likely to be the most susceptible to extreme and prolonged precipitation events by the end of the century. Insights from this work will contribute toward a comprehensive understanding of the potential impacts of climate change on the Gulf coast.

Date

3-21-2025

Committee Chair

Rohli, Robert V

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Available for download on Tuesday, March 14, 2028

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