Oceanography and Atmospheric Sciences and Meteorology Commons^™

The Mobility Of Long-Lived Radioisotopes And Their Burial In The Marine Environment, Neil Redmond

Dissertations

Marine sediments record chemical signals that reflect past environmental conditions. It is important to establish how these signals are created and whether they may be altered over time so that they can be useful for reconstructing ocean history. Measurements of uranium isotopes are used as a novel proxy for sedimentary diagenetic processes (Chapter 2). Because ²³⁴U can be ejected from mineral lattice during the decay of ²³⁸U, it creates a pool of U in porewater that is potentially mobilized and then deposited elsewhere in the core. We found that alpha-recoiled ²³⁴U is sensitive to differences in sediment …

Assessing Dynamics And Trends Of Co2 Flux On The Louisiana Shelf, Claire Mcguire

Master's Theses

The Gulf of Mexico on an annual timescale acts as a sink for ­CO₂. Previous studies have investigated regional-scale trends in the Gulf based on model output. In our investigation of the northern Gulf of Mexico, and especially the area surrounding the Louisiana delta, we found different trends compared with previous studies of the open ocean Gulf and broader shelf region. Predictions of global patterns of the ocean CO₂ cycle require regional studies of unique areas like the Louisiana Shelf. The Louisiana Shelf is a shallow system, has input from river systems, experiences seasonal hypoxia, and is …

Understanding The Flow Dynamics Of The Pearl River, Ms, Through Hydrodynamic Modeling, Nahruma Mehzabeen Pieu

Master's Theses

The Pearl River brings fresh water and nutrients into Lake Borgne regulating conditions for oyster growth in estuarine waters. However, there are no flow measurement stations installed on East Pearl or West Pearl either at the river outlets or after the upstream bifurcation of the Pearl. This study aims to model the Lower Pearl River to understand the flow dynamics in the major branches, and to determine the final outflow distribution into the Mississippi Sound, aiming to improve river forcing for ocean models studying estuarine dynamics of the Mississippi Sound.

Synthetic meandering bathymetry with updated banks is developed and applied …

Drinking Water Contaminants: Lead, Bruce I. Dvorak, Becky M. Schuerman

Department of Civil and Environmental Engineering: Faculty Publications

Any lead exposure, even low levels, can be a serious health concern, especially for infants, children, and developing fetuses. This NebGuide discusses how to safely manage lead in a domestic water supply (or often referred to as a private well). This NebGuide includes discussion related to topics such as lead services lines and changes in public water supply regulations related to lead in drinking water.

Modeling Potential Damages Of Hurricanes At The Facility Scale: A Case Study Of Eglin Air Force Base, Alexander J. Baldwin, Christopher M. Chini, Steven J. Schuldt, Justin D. Delorit

Faculty Publications

Tropical cyclones have intensified and are expected to strengthen throughout the 21st century due to climate change impacts. Storm intensification poses a serious threat to coastal municipalities and infrastructure that are not designed to withstand future wind and storm surge potential. Coupled modeling software has been widely used to replicate extreme weather events and simulate climate change effects to understand the magnitude of vulnerability coastal regions face. However, these studies are often conducted at too coarse resolutions to provide decision makers with actionable information for facility-level adaptation. This study addresses this limitation using a coupled modeling approach by simulating climate-intensified …

Estimation Of Quantitative Genetic Parameters Of The Eastern Oyster (Crassostrea Virginica) In The Gulf Of Mexico, Heather King

Master's Theses

The decline of natural oyster reefs in Gulf of Mexico (Gulf) states has stimulated the development of aquaculture to support the industry and restoration programs. Gulf habitats feature diverse salinity environments that may require oysters bred for habitat-specific optimal genetic characteristics. In this work, genetic parameters for performance in habitats with different salinity were estimated. In September 2020, 102 males and 102 females sourced from 17 natural reefs across the northern Gulf were bred according to 2 males x 2 females non-overlapping factorial crossing designs, resulting in 204 full and half sibs. All families were pooled after fertilization according to …

Importance Of Vegetation In Tsunami Mitigation: Evidence From Large Eddy Simulations With Fluid-Structure Interactions, Abhishek Mukherjee

Dissertations

Communities worldwide are increasingly interested in nature-based solutions like coastal forests for the mitigation of coastal risks. Still, it remains unclear how much protective benefit vegetation provides, particularly in the limit of highly energetic flows after tsunami impact. The present thesis, using a three-dimensional incompressible computational fluid dynamics model with a fluid-structure interaction approach, aims to quantify how energy reflection and dissipation vary with different degrees of rigidity and vegetation density of a coastal forest.

In this study, tree trunks are represented as cylinders, and the elastic modulus of hardwood trees such as pine or oak is used to characterize …

Toxicological Effects Assessment For Wildlife In The 21st Century: Review Of Current Methods And Recommendations For A Path Forward, Thomas G. Bean, Val R. Beasley, Philippe Berny, Karen M. Eisenreich, John E. Elliott, Margaret L. Eng, Phyllis C. Fuchsman, Mark S. Johnson, Mason D. King, Rafael Mateo, Carolyn B. Meyer, Christopher J. Salice, Barnett A. Rattner

United States Geological Survey: Staff Publications

Model species (e.g., granivorous gamebirds, waterfowl, passerines, domesticated rodents) have been used for decades in guideline laboratory tests to generate survival, growth, and reproductive data for prospective ecological risk assessments (ERAs) for birds and mammals, while officially adopted risk assessment schemes for amphibians and reptiles do not exist. There are recognized shortcomings of current in vivo methods as well as uncertainty around the extent to which species with different life histories (e.g., terrestrial amphibians, reptiles, bats) than these commonly used models are protected by existing ERA frameworks. Approaches other than validating additional animal models for testing are being developed, but …

2023 May 25 - Tennessee Weekly Drought Summary, Tennessee Climate Office, East Tennessee State University

Tennessee Climate Office Weekly Drought Summaries

No abstract provided.

Ecology Of Viruses In Marine And Coastal Oxygen-Depleted Waters, Sophie Jurgensen

LSU Doctoral Dissertations

Deoxygenation of marine and coastal waters, both caused and exacerbated by a suite of abiotic and biotic factors, has been documented for more than sixty years. The incidence and severity of low-oxygen areas is predicted to expand globally in the coming decades. Despite their colloquial moniker “dead zones,” low-oxygen areas contain thriving and diverse microorganisms that have significant impacts on global biogeochemical cycles including contributing to positive feedback loops that further expand low-oxygen areas. While the diversity and activity of these microorganisms is beginning to be elucidated, the ecology of their viruses is particularly understudied. In this dissertation, I present …

Agricultural Shocks On Household Stability: A Case Study Of Tanzania Maize Farmers, Zimmi Silonda Ndlovu

Master's Theses

As the global populations grow, the need for stronger agricultural resilience in areas with high food insecurity like Sub-Saharan Africa (SSA) is a must. Crop failure due to climate related events has increased substantially over the past decade, raising the risks to vulnerable groups like subsistence farmers. Understanding the effects of climate variability on farmers and their crops is a pivotal step towards increasing resilience and productivity. In this paper I approach this question using a Linear Probability Fixed-effects Model on Tanzanian Panel Survey data with monthly temperature and precipitation for years 2008 to 2013. Results suggest a negative relationship …

2023 May 18 - Tennessee Weekly Drought Summary, Tennessee Climate Office, East Tennessee State University

Tennessee Climate Office Weekly Drought Summaries

No abstract provided.

A Gridded Co2 Emissions Inventory For Portland, Or, James E. Powell

Dissertations and Theses

Here we develop a new high resolution inventory of CO₂ emissions for the three Oregon counties which comprise the bulk of the City of Portland, Oregon, USA. Locally curated and long-running data collection efforts for on-road traffic activity and emission rates are used to model on-road emissions, and a new survey of the area's natural gas network informs the building energy model. The inventory estimates total emissions of CO₂ for each hour of the year 2018 in the on-road, residential, and commercial building sectors at 1 km² resolution. The onroad inventory compares to within 3% with an …

Understanding The Impacts Of Topobathymetric Data On Storm Surge Model Predictions, Sydni Crain

Master's Theses

The topobathymetric characteristics of a region are regularly altered by natural and anthropogenic causes. This directly impacts the resulting storm surge during a hurricane. The primary goal of this research was to gain a better understanding of the impact that topography and bathymetry have on storm surge models, particularly the Advanced Circulation (ADCIRC) Model. Hurricane Zeta (2020) and Hurricane Ida (2021) were chosen as case studies; therefore, the Gulf of Mexico (GOM) was chosen as the study site. This research was completed by comparing ADCIRC storm surge results which were based on older, lower-resolution data with results derived from more …

Analysis Of Weather-Related Flight Delays At 13 United States Airports From 2004-2019 Using A Time Series And Support Vector Regression, Caroline E. Sleeper

Theses and Dissertations

This study seeks to investigate weather-related flight delay trends at 13 United States airports. Flight delay data were collected from 2004-2019 and normalized by airport operations data. Using Support Vector Regression (SVR), visual trends were identified. Further analysis was conducted by comparing all four meteorological seasons through computing 95% bootstrap confidence intervals on their means. Finally, precipitation and snowfall data were correlated with normalized delays to investigate how they are related. This study found that the season with the highest normalized delay values is heavily dependent upon location. Most airports saw a decrease in the SVR line at some point …

Evaluating The Relationship Between Methane Seeps And Seafloor Geomorphology On The Northern Us Atlantic Margin, Gabriel Hernandez

Theses and Dissertations

Methane seeps are a transport pathway for carbon from seafloor sediments to the marine environment with important implications for global biogeochemical cycling. Accordingly, there is substantial interest in better understanding the processes that control seep location and predicting the distribution of seeps with existing seafloor datasets. Visual evaluation of methane seeps, in multibeam sonar water column data, suggests a spatial relationship between seeps and specific seafloor morphologic features such as ridge crests. In this thesis, seafloor geomorphology at 1996 seep detection sites on the US Atlantic margin was quantitatively characterized by geomorphologic phonotype, bathymetric position index, slope, rugosity, and aspect …

Quantifying Seasonal And Annual Precipitation Variability On San Salvador Island, Bahamas Using Surface Observations And Satellite Estimates., John Bryson Wells

Theses and Dissertations

San Salvador Island is a small Bahamian island located in the subtropics just north of the Tropic of Cancer. Due to its subtropical location, the island is influenced by both mid-latitude and tropical weather patterns. These weather patterns vary in scale from localized convective uplift to synoptic-scale systems. This study compares satellite-derived estimates of precipitation and rain gauge observations from June 2019 through September 2021 to evaluate the relationship between the two datasets. This study then uses the satellite-derived estimates of precipitation over a 20-year period to quantify annual and seasonal variability in precipitation on San Salvador. Corroborating past research, …

Protecting The Vulnerable: Tornado Sheltering And Communication Of Public Shelters With A Case Study From The Covid-19 Pandemic, Craig Douglas Croskery

Theses and Dissertations

One of the greatest natural hazards that is faced with in much of the United States are tornadoes. Despite improvements in the warning processes, the risk of significant loss of life remains high. That is particularly true with vulnerable communities which have higher proportions of mobile homes; however, violent tornadoes are very difficult to manage in permanent homes or buildings as well. As a result, tornado shelters have been built in some communities and have become available to the public. However, their presence is intermittent, and there are many tornado-prone areas that lack such shelters.

After a public survey, it …

Verification Of The Localized Aviation Mos Program (Lamp) At Major Us Airports For Ifr Conditions, Mackenzie O'Rourke

Theses and Dissertations

The objective of this research is to quantify the LAMP’s performance when forecasting for IFR conditions at specific major airports for forecast hours one, three, six, and twelve, and further determine how the LAMP performs seasonally at those specific airports and forecast hours. Two by two contingency tables were used to calculate the Probability of Detection (POD), False Alarm Ratio (FAR), Critical Success Index (CSI), Heidke Skill Score (HSS), and Bias score. The results show that the LAMP performs relatively better in the cool season compared to the warm season consistently at each chosen airport, and that the LAMP performs …

Tornado Outbreak False Alarm Probabilistic Forecasts With Machine Learning, Kirsten Reed Snodgrass

Theses and Dissertations

Tornadic outbreaks occur annually, causing fatalities and millions of dollars in damage. By improving forecasts, the public can be better equipped to act prior to an event. False alarms (FAs) can hinder the public’s ability (or willingness) to act. As such, a probabilistic FA forecasting scheme would be beneficial to improving public response to outbreaks.

Here, a machine learning approach is employed to predict FA likelihood from Storm Prediction Center (SPC) tornado outbreak forecasts. A database of hit and FA outbreak forecasts spanning 2010 – 2020 was developed using historical SPC convective outlooks and the SPC Storm Reports database. Weather …