Oceanography and Atmospheric Sciences and Meteorology Commons^™

Regional Variability In Tornado Tracks: A Gis-Based Study Of Surface Roughness And Land Cover Differences Between The Lower Midwest And Southeast United States, Joshua Morgan Dison

Theses and Dissertations

Throughout the years, much research has been dedicated to the physical processes leading to tornadogenesis and tornado decay. Much of this research is centered around the inner workings of the supercell itself. Recent studies are now showing that tornadogenesis and decay processes may be generated by interactions with the Earth’s surface. This study examines longtrack tornadoes from 2001-2016 in the southeast and lower Midwest regions of the United States. Utilizing the National Land Cover Database (NLCD) and American Meteorological Society / Environmental Protection Agency / Regulatory Model (AERsurface) surface roughness values, efforts are made to see if statistical significance is …

Environmental Monitoring In Shallow Lakes: Public Health Threats In Urban Waters, Kyleigh E. Johnson

Theses and Dissertations

Lakes are an integral part of urban and suburban communities, providing ecological, recreational, and public health benefits. Many of these lakes are located in densely populated areas and are subject to urban influences on water quality. Algal toxins and Escherichia coli are two common recreational concerns. Algal toxins come from harmful algal blooms that are influenced by nutrient availability and temperature, while bacteria are often introduced through run-off and animal waste. Sampling every 3-4 weeks from May-October 2025 allowed for the assessment of seasonal patterns and site-specific differences across nine lakes in the Richmond area. The highest bacterial concentrations appeared …

Interpretable Alignment Of Textual Weather Reports With Local Sensor Time Series For Extreme Weather Event Visualization, Juan Luis Garza

Theses and Dissertations

This thesis presents an automated and interpretable pipeline that links natural-language weather narratives with local meteorological sensor time series. Using large language models, NOAA-style event reports are transformed into structured records capturing event type, timing, descriptive context, and uncertainty. Each extracted event is aligned with harmonized temperature, precipitation, and wind measurements from nearby weather stations, enabling systematic comparisons between narrative evidence and observed atmospheric conditions.

Across roughly fifty stations and more than two thousand events, the analyses show that discrepancies between narrative descriptions and sensor behavior arise primarily from spatial separation rather than from temporal offsets, sensor preprocessing artifacts, or …

Benthic Infaunal Responses To Shoreline Restoration, Jessica Lauren Cline

Theses and Dissertations

In the age of increasing urban coastal sprawl, natural shorelines are being replaced by hard armoring structures, which result in the loss of valuable ecosystem services. Hybrid living shorelines, areas that include limited and less intensive armoring strategies paired with the integration of plants and other natural materials, present an opportunity to marry the need for more aggressive stabilization with the continued preservation of ecosystem functions and biological communities. This project uses benthic infauna to evaluate the success of a living shoreline installation in Palm Bay, Florida. The deployment features experimental treatments of breakwaters and red mangroves to explore how …

Validation And Proposed Expansion Of The Data-Driven D Region Model, Kevin M. Watson

Theses and Dissertations

Predicting ionosphere effects on radio wave propagation is critical for communications and over-the-horizon radar systems. The D region is challenging to model for several reasons, one of which is chemical complexity. Ion density changes during sunrise/sunset introduce substantial uncertainty in electron density profiles (EDPs). The Data Driven D Region (D3R) model solves electron densities through an ion chemistry model and assimilates relevant space weather inputs. This study evaluates D3R against the Faraday International Reference Ionosphere (FIRI) and measurements using Very Low Frequency (VLF) propagation paths. Space weather event impacts on D3R EDPs are evaluated during the disturbed period from 8-12 …

Satellite-Based Identification Of Mesoscale And Submesoscale Eddies And Fronts In The Gulf Of Mexico, Ethan Cruz

Theses and Dissertations

Mesoscale and submesoscale processes in the Gulf of Mexico (GoM) are fundamental in shaping the region’s physical and biogeochemical ocean dynamics. Advances in high-resolution satellite observations now allow detailed detection of submesoscale (< 25 km radius) and mesoscale eddies and ocean fronts, which drive heat, nutrient, and carbon fluxes. This dissertation integrates two complementary investigations: (1) a comparison of eddy-tracking algorithms: Contour Tracing (CT) and Temperature Thresholding (TT), applied to Optimum Interpolation Sea Surface Temperature (OISST, 1/4°) and Operational Sea Surface Temperature and Ice Analysis (OSTIA, 1/20°) products; and (2) a comparative evaluation of three ocean front detection algorithms: Canny Edge Detection (Canny), the Cayula–Cornillon Algorithm (CCA), and the Belkin–O’Reilly Algorithm (BOA), across multiple satellite-derived parameters, including sea surface temperature (SST), sea surface salinity (SSS), chlorophyll-a (Chl-a), and altimetry-derived absolute dynamic topography (ADT). The eddy-tracking analysis shows that the higher-resolution OSTIA consistently detected more eddies than OISST, with TT performing best during winter when SST gradients were strongest. The front detection analysis, incorporating datasets from the Surface Water and Ocean Topography (SWOT) and Plankton, Aerosol, Cloud, Ocean Ecosystem (PACE) missions, was evaluated under diverse conditions, including flood and drought periods, Loop Current phase changes, and extreme weather events. A machine learning–based Gaussian Mixture Modeling (GMM) approach was also developed, providing a novel framework for dynamic front detection. By benchmarking traditional and machine learning methods, this integrated study identifies optimal algorithm–dataset combinations for resolving submesoscale and mesoscale features in the GoM, with applicability to other regions.

Exploring The Use Of A Random Forest In Correcting Gfs Tropical Cyclone Landfall Errors, Victoria Grace Maxwell

Theses and Dissertations

While Tropical Cyclone (TC) track forecasting has improved over the years it has been slow. These improvements can be attributed to increased computer capability and better model inputs. Machine learning has been used for forecasting different TC track and intensity. The study here looks to use a Random Forest to predict the TC latitude/longitude “landfall” at 72-hr and quantify improvements to the GFS forecast. Principal Component Analysis was used to reduce the dimensionality of the meteorological variables. Stepwise regression was used to determine the principal components that were important for forecasting landfall. These variables were then tested with a multivariate …

An Investigation Into The Inclusivity, Methodology, And Education Of Severe Weather In K-12 Schools, Stephen Holden Wooten

Theses and Dissertations

Schools are a focal point in the lives of everyone in the community, especially teachers, parents, and students. Investigating the connection between these individuals and tornadoes by identifying shortcomings in education, training, and emergency procedures can induce more effective and informed decision-making for future encounters. This study evaluated the inclusivity of tornado protocols for students with disabilities, uncovered where parents prefer their child to shelter in early dismissal situations and clarified how extensively natural hazard education and tornado drills are covered in schools. Two surveys and semi-structured interviews were used to obtain responses from earth science teachers, K-12 guardians, and …

Atmospheric Turbulence Education Effects On Flight Anxiety, Megan A. Hanna

Theses and Dissertations

This study examines the effect of turbulence education on flight anxiety. A pre-post methodology measured students’ anxiety levels before and after a study abroad flight, using an educational video during the pre-flight survey to change their feelings. The Flight Anxiety Situations (FAS) questionnaire assessed anxiety at three survey points: pre-video, post-video, and post-flight. Qualitative analysis using Friedman’s test and the Wilcoxon Signed-rank test, indicated that turbulence education effectively decreased generalized and anticipatory flight anxiety, particularly in non-phobic students. Text analysis of open-ended responses suggested increased scientific knowledge post-video helped students apply technical atmospheric processes to their feelings. Turbulence education was …

Evaluating Rainfall Sensitivity Over Land To Tropical Cyclone Parameters Using Idealized Wrf, Madison C. Yawn

Theses and Dissertations

Tropical cyclones (TCs) are extreme weather events impacting the United States nearly every year. These events often cause severe damage due to the associated responses they produce including storm surge and rainfall, and the accurate estimation of these TC hazards is necessary to support coastal engineering, risk assessment, and emergency management activities. Evaluating TC-driven hazards is often done in combination with numerical models to simulate how environmental interactions alter the physical processes and responses of these storms. The purpose of this study was to simulate synthetic TC events using the Advanced Weather Research and Forecasting (WRF) model to understand how …

Real-Time Enhanced Tornado Warning Product Guidance Based On Tornado Debris Signature Height And Population Density, Alexander Cooke

Theses and Dissertations

This research aims to develop an operational program for enhancing real-time tornado warning capabilities by integrating tornado debris signature (TDS) analysis with population impact assessment. The proposed Python-based tool will ingest Level II radar data to identify and analyze TDS, estimating tornado intensity based on maximum TDS height. For high-intensity tornadoes, the program will project the potential impact area using storm motion vectors and integrate this with population density data. The system will assess whether the situation meets National Weather Service criteria for enhanced warning products, providing forecasters with rapid, objective guidance for critical warning decisions. The program’s performance will …

Influence Of Horizontal Grid Spacing On Numerical Weather Prediction Simulations Of Clear Air Turbulence, Kailah Rose Gordon

Theses and Dissertations

The focus of this research was to analyze the influence of horizontal grid spacing on numerical simulations of kinetic and thermal forced clear air turbulence (CAT) by quantifying uncertainty using a resolution ensemble. Previous studies indicated that microscale (< 1km) spatial resolutions are necessary to resolve turbulent kinetic energy (TKE) with low uncertainty. Six case studies of moderate or greater CAT, from pilot reports, were simulated at six horizontal grid spacings including 1, 2, 4, 8, 16, and 32km using the Weather Research and Forecast (WRF) Model. Results showed that grid spacing does influence the magnitude of uncertainty; however, the relationship between the grid spacings varied with the type of CAT being simulated and the addition of the cumulus parameterization scheme for grid spacings greater than 4km. Overall, higher precision was found between convective resolutions (1-4km), indicating that microscale resolutions are not necessary to precisely simulate TKE for CAT forecasts.

From Tree Rings To Streamflow: Reconstructing The Hydroclimatic History Of The Mississippi River Basin Over The Past Millennia, Brandon Mcdaniel

Theses and Dissertations

The Mississippi River Basin (MRB), the largest watershed in the United States, plays a central role in shaping regional hydroclimate. This study reconstructs streamflow variability in the MRB from the year 1200 to 2005 by applying principal component regression to streamflow data from 51 gauges and the North American Drought Atlas (NADA), a tree-ring-based reconstruction of the summer self-calibrating Palmer Drought Severity Index. Verification statistics indicated strong predictive skill across the domain. These findings provide critical insight into long-term hydroclimatic variability in the MRB and underscore the value of paleoclimate records for improving water resource assessments.

The Role Of Enso Diversity In Modulating Tornadic Activity In The United States, Davis Boyd Newton

Theses and Dissertations

Tornado activity in the United States is influenced by large-scale climate patterns, especially by the El Niño-Southern Oscillation (ENSO). While prior research has explored ENSO’s impact on severe weather, the influence of ENSO flavors, Central Pacific (CP) and Eastern Pacific (EP), on tornadic activity remains understudied. Using tornado records, reanalysis data, and sea surface temperature anomalies, we assess how convective available potential energy (CAPE), wind shear, and jet stream dynamics influence tornado frequency and distribution. Results indicate that CP La Niña years had significant increases in tornado frequency, particularly across the Midwest, Central Plains, and Southeast. EP ENSO years had …

Integrating Case Studies With Meteorologists’ Insight: Assessing Meteorologists’ Perception And Utilization Of Composite Indices, Brianna Marie Salazar

Theses and Dissertations

Meteorologists from sectors, including broadcast, academia, and operations, use derived composite indices such as 0-1km and 0-3km energy helicity index (EHI), effective-layer supercell composite parameter (SCP), fixed-layer and effective layer significant tornado parameter (STP), in addition to other resources, when developing severe local storm forecasts. This study utilizes the Weather Research and Forecasting (WRF) model to create simulations of composite indices for two tornado-producing events: 31 March 2023 and 3 May 1999. With modifications to geographical location, these simulated scenarios are then utilized in the survey to gauge how meteorologists assess where tornado potential is highest. Additionally, a combination of …

Analyzing Lf/Vlf Lightning Waveforms To Estimate D-Region Electron Density Profiles: Process, Application, And Comparison, William R. Smith

Theses and Dissertations

Lightning waveforms in the low frequency (LF; 30-300 kHz) and the very low frequency (VLF; 3-30 kHz) can be exploited to produce data-driven ionospheric Dregion electron density profile (EDP) estimates with significantly higher spatial and temporal coverage than previously available. The lightning waveforms used in this paper are signals detected in the LF/VLF of negative cloud-to-ground lightning by the Earth Networks Total Lightning Detection Network. Each waveform contains a ground wave and a time-delayed ionospheric reflection. The time delay between the ground wave and ionospheric reflection has previously been used to estimate a single specular reflection altitude, where LF/VLF emissions …

Spatiotemporal Prediction Of Atmospheric Events Through Recurrent Deep Learning Model, Brian W. F. Popick

Theses and Dissertations

The main contributions of this research is to add to the growing library of literature on the use of deep learning algorithms for the spatiotemporal prediction of dangerous atmospheric and hydrologic phenomena. Specifically, we develop novel attention-based and non-attention-based recurrent neural network frameworks to produce short-range sequential forecasts for lightning and tornado occurrences. Additionally, we introduce methods that account for and include error in the model tuning process to generate more reliable models. Furthermore, we have created a lightweight spatiotemporal tornadic prediction dataset that we plan to make publicly available. The first component of this research develops three novel spatiotemporal …

Evaluating Weather Effects On Sortie Generation Using Discrete Event Simulation, Markus Case

Theses and Dissertations

United States Air Force (USAF) operations rely on sortie generation, a complex system involving aircraft maintenance, operational planning, munitions, security forces, and aircrew. Failures in any of these areas can jeopardize a mission, and extreme weather events such as lightning, high winds, and snow further complicate operations. This thesis examines the impact of extreme weather on sortie generation, focusing on developing a data-driven discrete-event simulation (DES) to predict generation timelines and identify high-risk areas. The model allows users to adjust key inputs, including the month, number of aircraft, processing times, and personnel/equipment availability. By simulating real-world conditions, the model helps …

Geomorphic Evolution Of St. Augustine Inlet, St. Johns County, Florida, Kristen Becker

Theses and Dissertations

Tidal inlets interrupt longshore sediment transport, influencing adjacent beach morphology and allowing the exchange of water and sediment between the open oceans and protected back barrier bay. Inlets evolve through a combination of natural processes and are highly dynamic zones where sediment exchanges cause shifting shoreline positions nearby and create new morphological features. Barrier islands/beaches that are close in proximity to inlets evolve and are an important natural feature that dissipates wave energy and protects inland areas. Both natural and anthropogenic processes that affect barrier islands will be investigated during this study, including storm activity, waves, wind, water level, and …

Discrimination The Roles Of Anthropogenic Greenhouse Gases And Aerosols On Tropical Cyclone Frequency From Downscaling Cmip6 Models, George Gyabaah

Theses and Dissertations

Tropical cyclones (TCs) are devastating disasters, yet predicting their future activity remains highly uncertain. To better understand the impacts of different anthropogenic forcings, specifically greenhouse gases (GHG) and aerosols on the TCs, I downscaled the single forcing experiments of 11 CMIP6 models in the Columbia HAZard Model (CHAZ). This analysis focused on changes in the distribution of the North Atlantic (ATL) and Western North Pacific (WNP) basins and explored the shift in environmental variables that drive them. We then used the formulation of the genesis component of CHAZ as a constraint to quantify the relative contribution of each predictor relative …

Offshore Detachment Of The Winyah Bay Plume Through Ekman Dynamics Under Upwelling Conditions, Isabella Moore

Theses and Dissertations

ABSTRACT River plumes play a crucial role in coastal ecosystems by influencing land-ocean interactions, primary production, water quality, and ocean circulation. This study presents observations of a buoyant river plume off Winyah Bay, South Carolina (USA), conducted in 2020 and 2021. Observations comprised CTD casts and shipborne ADCP profiles as well as near surface flow measurements from a floating platform and microstructure profiles in uprising mode. This research focuses on the offshore transport of the buoyant water through Ekman dynamics under upwelling-favorable conditions. Under varying wind forcing and stratification scenarios, the Winyah Bay plume either remains near the coast or …

Assessing The Gut Content Of Styela Plicata: A Benthic Filter Feeder In The Indian River Lagoon, Honor Lily Triumph Edmands

Theses and Dissertations

The Indian River Lagoon (IRL) has experienced declining water quality due to human activities involving nutrient input, leading to Harmful Algal Blooms (HABs). The Living Docks program affixes oyster mats to dock pilings to promote the settlement and recruitment of benthic filter feeders for water quality improvement. However, questions remain about filtering efficiencies of organisms that make up the mat communities, and whether organisms remove harmful species from the IRL. The pleated sea squirt, Styela plicata, is a common oyster mat resident. The goal of this thesis was to investigate what phytoplankton and bacteria S. plicata consumes, and if …

Calibration And Use Of The Transparency Tube As An Estimate Of Turbidity: An Analysis Of Factors Controlling Light Attenuation In Estuarine Waters, Makenna Leigh Thompson

Theses and Dissertations

The transparency tube is low-cost, portable, and easy to use to measure the transparency or clarity of the water. Filling the tube with water creates a small-scale water column where water will be slowly drained out of the bottom until the Secchi disk at the bottom of the tube is visible from the top opening, and the depth of the remaining water in the tube is recorded in centimeters. Unlike traditional Secchi disk measurements, the advantage of this instrument is that sampling depth in highly turbid waters is possible with a centimeter scale resolution. Transparency tube measurement, through careful calibrations, …

Remote Profiling Of Atmospheric Turbulence: Enhanced Resolution With Stacked Rayleigh Beacons In Tardis, Benjamin C. Wilson

Theses and Dissertations

A stacked beacon turbulence profiling methodology has been introduced and applied to have increased profiling on the Turbulence and Aerosol Research and Investigation System (TARDIS). The model was derived and demonstrated the applicability through discussion on data processing and inversion processes. The methodology was applied for two different nighttime experiments, one in Summer and one in Fall. C 2 n profiles were derived into the 1300 m altitude ranges for both nights and the summer experiment was compared to a co-located DELTA Sky measurements and LEEDR generated Climatological profiles. The comparison implied promise in the methodology with additional work needed …

A Statistical Fetch Model For Water Wave Glint Correction Using Worldview-3 Imagery, Amanda Jade Quintanilla

Theses and Dissertations

Sun glint in satellite imagery of the water surface contaminates the upwelling signal received by a detector. Many models exist that attempt to correct for this wave facet effect and phenomena. In this work a model for sun glint correction is created using the comparison of image transects between two nearly simultaneously collected images of the same area, although with differing sensor geometry. One image utilized in this research is almost entirely glint free while the other is contaminated by water wave facet glint. Although many models for removing sun glint exist based on various techniques, none are completely accurate, …

Assessing The Relationship Between The Quasi-Biennial Oscillation And D-Region Electron Density, Natalie R. Wirth

Theses and Dissertations

High frequency (HF) communication is a vital aspect of military communication and is highly reliant upon ionospheric conditions. The variation in electron density within the lowest echelon of the ionosphere, the D-region, can significantly impact HF signals, making communication inconsistent and unreliable for these wavelengths. Despite the D-region’s important, research in this area mainly focuses on understanding the impact of space weather anomalies on the upper ionosphere, particularly its higher layers, with relatively little exploration of the D-region. This region, situated closest to the troposphere and stratosphere, has been definitively linked to solar weather events like solar flares and geomagnetic …

Global Empirical Model Of Sporadic-E Occurrence Rates, Eli V. Parsch

Theses and Dissertations

Encompassing the Earth, the ionosphere presents unique challenges to modern communication, navigation, and surveillance technologies. Intense ionization enhancements known as sporadic-E (Es), can degrade and disrupt signals in unpredictable ways. Much work has been done to understand this phenomenon and more recent efforts have attempted to model its behavior and impacts. However, there have been limited efforts at modeling global Es occurrence rates (OR) at high time resolutions. This study develops a global empirical model of blanketing sporadic-E (fbEs) occurrence rates using a Karhunen-Lo´eve Expansion (KLE) of global fbEs OR climatologies built with Global Positioning System radio occultations (GPS-RO) and …

Investigation Of High-Latitude Gnss Radio Occulation Sporadic-E And Auroral-E Measurements, Kyle D. Roberts

Theses and Dissertations

Abnormal sporadic-E (E_s) occurrences were found in the high latitude regions during a recent climatology study by (Hodos, 2022), that calculated sporadic-E occurrence rates derived from a data set of GPS radio occultation (GPS-RO) and ionosondes. In this study, sporadic-E GNSS-RO techniques are shown to falsely attribute sporadic-E events to auroral-E (E_a) events. A comparative study is conducted on GPS-RO measurement techniques to find false occurrence rates for various RO techniques using a single ionosonde site in Gakona, Alaska. Phase-based RO techniques were found to be more likely to falsely attribute sporadic-E as auroral-E, while amplitude …

Modeling Lightning Flashes In Dissimilar Non-Homogeneous Clouds, Scott R. Wolff

Theses and Dissertations

A new methodology for near-infrared lightning radiative transfer through clouds is presented. High-resolution weather modeling is used to generate realistic three-dimensional non-homogeneous clouds, which are then used as environments for a Monte Carlo simulation of photon multiple scattering from approximations of lightning flashes. Resultant emissions from the cloud tops are in line with previous studies and satellite observations.

Center Fixing Tropical Depressions And Tropical Storms Using Machine Learning-Nighttime Visible Imagery, Nathan K. Stanford

Theses and Dissertations

The first step in most TC-retrieval algorithms is determining the storm’s central position. In mature TCs, the center is highlighted by a distinct eye and curved band pattern; however, in intensifying and decaying storms, the center is often obscured by thick clouds or overlying cirrus. This study assesses the benefits of incorporating machine learning-derived nighttime visual imagery to improve analysis of center fix in intensifying and decaying TD- and TS-strength TCs during periods of darkness and when polar orbiting satellites are unavailable. The study is divided into two parts: the first, an objective analysis using the ARCHER-2 algorithm, and the …