Physical Sciences and Mathematics Commons^™

The Influences Of Sea-Surface Temperature Uncertainty On Cool-Season High-Shear, Low Cape Severe Weather Event Predictability In The Southeast United States, Michelle Rose Spencer

Theses and Dissertations

Environments conducive to severe weather and tornadoes occur throughout the southeastern United States, particularly during the cold-season. Throughout the cold-season, severe weather in this region predominantly occurs in environments characterized by high-shear, low-CAPE (HSLC). An important aspect to the production of severe weather in HSLC environments in the southeast United States is that air parcels that help contribute to the limited positive-buoyancy generation originate over areas such as the Gulf of Mexico, western Caribbean Sea, and western Atlantic Ocean. These relatively warm bodies of water, particularly outside of the cooler coastal shelf regions, allow the air parcels to warm and …

Transport And Fate Of Phosphorus In The Nearshore Zone Of Lake Michigan, Nathan Van Ee

Theses and Dissertations

Bioavailable phosphorus loads exported to Lake Michigan from the Milwaukee and Sheboygan River Watersheds appear to have increased in the last 40 years despite meeting total phosphorus (TP) loading goals set by the Great Lakes Water Quality Agreement (GLWQA).Overall, bioavailability of P delivered from the Milwaukee and Sheboygan Rivers was highest during the warmer months, which coincides with the nearshore nuisance algae growth season. However, first order loss rates of SRP calculated during baseflow recession were also greatest during the summer, suggesting that increased river residence time during the summer could reduce export of bioavailable P. Observations of phosphorus partitioning …

Assessment And Monitoring Of Deltaic Wetlands And Fluvial Systems: Refining And Validating A Multimetric Index Of Resaca Ecosystem Health, David Lecusay Jr.

Theses and Dissertations

Resacas are ancient distributary channels of the lower Rio Grande River historically serving as floodwater drainage pathways onto the Laguna Madre, Texas. Resacas provide numerous ecosystem services and critical habitat for many species. Mainly influenced by urbanization, integrating a multimetric index for assessing and monitoring resaca ecosystem health is required for adaptive management. The Resaca Health Index (RHI) integrates structural and functional components: (1) nonredundant metrics describing fish communities (Fish Community Index); (2) Trophic State Index derived from Secchi depth; (3) decay constant from riparian vegetation leaf litter decomposing in the water column; and (4) a riparian quality index based …

Snook (Centropomus Undecimalis) Behavior And Accelerometer Telemetry In The Bahia Grande Of Texas, Jonathan Truett Cawlfield

Theses and Dissertations

There has been very little study of the Texas population of snook. No studies have have looked at behavior in the Texas snook population. In this study we look at behavioral patterns and activity level in Lower Laguna Madre snook utilizing accelerometer telemetry tags. Twenty-one common snook were surgically implanted with tags and monitored from summer and fall of 2019 until September 2020. The accelerometer tags which sum acceleration over the x, y, and z planes calculated (ODBA) which was used to estimate behavior. This behavior was then compared with environmental data like diel period, tidal period, water temperature, and …

A South Polar View Of Late Paleozoic Glaciation: Physical Sedimentology And Provenance Of Glacial Successions In The Tasmanian And Transantarctic Basins, Elizabeth Rosa Woodford Ives

Theses and Dissertations

The Late Paleozoic Ice Age (LPIA; ~ 374 – 256 Ma) is the longest Phanerozoic icehouse interval. this interval in Earth’s history was largely defined by extensive glaciation of the southern hemisphere at both polar and temperate latitudes. Glaciers are powerful climatic and geologic actors, especially during icehouse periods, and widespread glaciation can have a significant influence on both regional and global climate and geology. Therefore, constraining the characteristics of LPIA glaciers is essential to developing a global-scale understanding of this key climatic event in Earth’s history. The manuscripts in this dissertation examine the sedimentology, transport directions, stratigraphy, and detrital …

Managing Water Resource And Land Use In Lower Rio Grande Valley Of South Texas Using A Groundwater Vulnerability Model, Leslie Soto Sanchez

Theses and Dissertations

The Lower Rio Grande Valley (LRGV) has three Metropolitan Statistical Areas. These are Brownsville-Harlingen, Laredo, and McAllen-Edinburg-Mission, the latter with a population of around 1 million people and had an estimated growth of 62% from the period of 2010-2018 (Texas State Data Center, 2020). Low precipitations, intensive agricultures as well as growth in the manufacturing and tourism industries have resulted in an increasing concern of scarce water supply especially the region relies primarily on a single water source, the Rio Grande River. These circumstances could potentially disrupt economic development, negatively affecting the local manufacturing industry, agriculture, and the community. With …

Changes In The Abundance And Distribution Of Benthic Mollusks In Polluted Sediments Of A Shallow Subtropical Estuary, Rachael Holtsberg Stark

Theses and Dissertations

The Indian River Lagoon (IRL) has been degraded by decades of eutrophication, and has accumulated an abundance of fine-grained, organic-rich sediments (muck). To quantify the impacts of organic sediments and environmental dredging, benthic mollusks were chosen to serve as bioindicators of environmental change, sediment health, and water quality. Data on species richness, biodiversity, and abundances was collected alongside sediment and water quality data before, during and after dredging. Organic sediment content was found to have an inverse logarithmic relationship benthic mollusk biodiversity, species richness, and abundance. Sediments low in percent organic content (0.7% to 6.1%) were located near the adjacent …

Development And Optimization Of A Denitrification System To Promote Biological Nutrient Removal In A Subtropical Estuary, Abigail Gering

Theses and Dissertations

Eutrophication impacts coastal ecosystems globally and triggers phytoplankton and algal blooms, leading to an increase in oxygen demand in the water column and sediments due to various biogeochemical processes. Naturally, biological nitrification, denitrification and anammox processes help to remove nitrogen predominately by nitrifying and denitrifying bacteria in the sediments. Eutrophic systems have increased nutrient and organic matter loading and are prone to the accumulation of ‘muddy’, fine-grained, organic-rich sediments (locally termed ‘muck’) that may not be able to support high enough populations of these bacteria, and therefore, may not adequately support nitrification/denitrification processes that would otherwise remove nitrogen. To decrease …

Ionospheric F-Layer Dipole Flute Instability Effects On Electromagnetic Scattering In A Magnetohydrodynamic Plasma, Andrew J. Knisely

Theses and Dissertations

The ionosphere has significant impact on radio frequency (RF) applications such as satellites, over-the-horizon radar, and commercial communication systems. The dynamic processes effecting the behavior of the ionic content leads to a variety of instabilities that adversely affect the quality of RF signals. In the F-layer ionosphere, flute instability persists, appearing as two radial regions of high and low density perturbations elongated along the earth's geomagnetic field lines. The sizes of flute structures are comparable to the wavelengths in the high frequency spectrum. The objective is to characterize the high frequency scattering of an incident field by developing a 3D …

Relationship Between Solar Energetic Particle He/H Abundance Ratios And Properties Of Flares And Cmes, Christopher R. Davidson

Theses and Dissertations

Previous studies have investigated the He/H elemental abundance ratios of Solar Energetic Particle (SEP) Events of energies above 4 MeV. Also, studies have investigated the correlations between SEPs, Coronal Mass Ejections (CME), and Solar Flares. This work finds the correlations between the >4 MeV He/H abundance ratios and the solar parameters from the SEP, CME, and solar flare associated with the abundance increases. 43 SEP events located at solar west longitude are analyzed to find the correlation coefficients. Highly significant correlation was found between the He/H abundance ratios and the following parameters: solar flare flux, solar flare fluence, CME linear …

Deep Learning For Weather Clustering And Forecasting, Nathaniel R. Beveridge

Theses and Dissertations

Clustering weather data is a valuable endeavor in multiple respects. The results can be used in various ways within a larger weather prediction framework or could simply serve as an analytical tool for characterizing climatic differences of a particular region of interest. This research proposes a methodology for clustering geographic locations based on the similarity in shape of their temperature time series over a long time horizon of approximately 11 months. To this end an emerging and powerful class of clustering techniques that leverages deep learning, called deep representation clustering (DRC), are utilized. Moreover, a time series specific DRC algorithm …

Development And Verification Of Extreme Space Weather Phenomena Models, Sophia G. Schwalbe

Theses and Dissertations

A range of 14 M-class flares from 1 June 2015 to 27 September 2016 were analyzed to find significant trends in electron frequency profile modeling using the GLobal airglOW (GLOW) model and radar parameters using a ray tracing algorithm developed by the Air Force Research Laboratory. GLOW was run for all the flares using three different solar spectrum schemes and an average of the three: the Hinteregger method, EUV flux model for aeronomic calculations (EUVAC), and a rebinned Flare Irradiance Spectrum Model (FISM) result. Comparing data for the E-layer where GLOW is most accurate, it was determined that GLOW using …

Profiling Atmospheric Turbulence Using A Dynamically Ranged Rayleigh Beacon System, Steven M. Zuraski

Theses and Dissertations

The effect of turbulence on a long range imaging system manifest as an image blur effect usually quantified by the phase distortions present in a system. The blurring effect is conceivably understood on the basis of measured strength of atmospheric turbulence profiled within the propagation volume. One method for obtaining a turbulence strength profile is by use of a dynamically ranged Rayleigh beacon system that exploits strategically varied beacon ranges along the propagation path, effectively deducing estimates of specific path segment contributions of the blurring aberrations affecting an optical imaging system. A system utilizing this technique has been designed, and …

Assessing Long-Term Coral Coverage At East And West Flower Garden Banks, Rebekah Alicia Hernandez

Theses and Dissertations

Coral reefs provide critical habitat for diverse benthic communities; however, more than 10% of existing reefs have been lost as a result of natural and anthropogenic stressors. While there has been a decline in reefs around the world, East and West Flower Garden Banks (FGBs), part of Flower Garden Banks National Marine Sanctuary (FGBNMS), have maintained > 50% live coral cover for over 27 years as revealed by the FGBNMS long-term monitoring (LTM) program. In the 1980’s, the LTM program at East and West FGBs was developed in response to the expansion of oil and gas exploration, anchoring, and fishing impacts …

Biochar Applications To The Remediation Of Lead And Polychlorinated Biphenyl Contaminated Water, Victory Itua Igberase

Theses and Dissertations

This study investigated the performance of biochar materials as adsorbents to remove Pb and polychlorinated biphenyl (PCB) in aqueous solutions. Batch adsorption and column experiment packed with biochar and geomaterials (pumice) in 1:1 volume ratio was evaluated to address the efficacy of biochar in removing Pb while only batch adsorption was employed for PCB removal with biochar materials. Overall, PT biochars performed the best (42–53 mg g−1) followed by BE biochars (10–32 mg g−1) and AB biochars (17–27 mg g−1) while high temperature biochars were favored in terms of maximum Pb adsorption capacity. Column Pb breakthrough showed similar results, with …

An Investigation Into The Thermodynamics Of Overland Tropical Cyclone Intensity Change In Weakly/Non-Baroclinic Environments, Michael Partrick Vossen

Theses and Dissertations

There are two leading theories regarding how tropical cyclones can maintain or increase their intensity over land in weakly to non-baroclinic environments. In the first, tropical cyclones are maintained overland by enhanced upward surface enthalpy fluxes facilitated by the tropical cyclone’s rains, whereas in the second, tropical cyclones are maintained by enhanced enthalpy fluxes under inflowing trajectories at larger radii from the cyclone’s center. These theories have yet to be rigorously tested, however. To rigorously test these hypotheses, this study uses a quasi-idealized version of the Weather Research and Forecasting model lacking parameterized radiation to test the sensitivity of overland …

Verification Of Environmental-Regime–Stratified Gfs Short-Range Vertical Sounding Forecasts, Dillon Blount

Theses and Dissertations

In recent years, the United States’ operational global numerical weather prediction model, the Global Forecast System (GFS), has been upgraded to include a new dynamical core and an updated turbulence parameterization. This updated turbulence parameterization uses a hybrid eddy-diffusivity, countergradient, and mass-flux formulation to approximate near-surface turbulent vertical mixing. The precise formulation used is based on the local stability, with the eddy-diffusivity, countergradient, and mass flux formulations used under stable, weakly unstable, and strongly unstable conditions, respectively. In this study, an objective classification of environmental regimes is used to verify GFS short-range vertical soundings, focusing on the planetary boundary layer …

Investigation Of Techniques And Their Application For The Cryopreservation Of Algal Species, Jazmine Leija

Theses and Dissertations

An alternative source for petroleum-based crude oils are algae derived biofuels. Fossil fuels are harmful for the environment, expensive and becoming scarce. There has been an increase in research on environmentally sustainable energy, using lipids derived from microalgae, which can be converted into biofuel. The use of microalgae as a source for biofuels has a lot of benefits including decreasing greenhouse gas emissions, rapid fuel production, absorption of carbon dioxide, and production of a renewable source of energy.

Algae cryopreservation aids in the maintenance of the best algae strains selected for producing lipids for biofuels. Cryopreservation will help minimize genetic …

A Biological Assessment Of Oyster Restoration Mats Throughout The Indian River Lagoon: Changes In Community Composition And Filtration Capacity Of Living Docks, Morgan Katherine Gilligan

Theses and Dissertations

Like many estuaries worldwide, the Indian River Lagoon (IRL), has seen a decline in resources and overall water quality due to human activities. There is a growing interest in implementing ecological engineering methods to restore water quality. One such method is the construction and deployment of oyster restoration mats on dock pilings, known as the Living Docks program. This community driven program was founded at Florida Tech with the goal of promoting the growth of filter feeding benthic organisms to improve local water quality. Since 2013, twelve docks have been deployed in the central IRL, spanning from Cape Canaveral (28º …

Studies On How Grooming Can Improve The Performance Of Fouling Control Coatings, Lauren Elizabeth Foy

Theses and Dissertations

Biofouling is the accumulation of unwanted organisms on a submerged surface. This can be a major issue to most marine activities. The most common approach to biofouling prevention on ship hulls is the application of fouling control coatings (FCC), which can be categorized as biocidal and biocide-free. Grooming has been proposed as a proactive method to maintain these coatings and extend their working lives. In 2010, Tribou first defined grooming as the systematic, gentle, and mechanical disruption and removal of fouling on a ship hull. For biocidal coatings, grooming maintains the active biocide contained in the coating, preventing organism attachment. …

Estimation Of The Planetary Boundary Layer Height: Part 1: Global Radar Wind Profiler Network Data; Part 2: A Comparison To Ceilometer Data, Holly Josephs

Theses and Dissertations

Two methods for estimating the planetary boundary layer, an algorithm to identify a maximum in the backscatter and a covariance wavelet transform method, are explored and applied to global radar wind profiler network data and ceilometer data respectively. The objective of the study is to establish that the data sources and algorithms can be used to estimate planetary boundary layer heights so that global studies can make use of these estimates. Data from the global network of wind profilers required significant restructuring and quality control in order to be used for the present study. The maximum backscatter identification algorithm was …

Investigating The Potential Of A Combined Air Quality-Heat Index In Predicting Mortality, Shayna Fever

Theses and Dissertations

Although the development of the Air Quality Index (AQI) has been significant in informing and protecting the public, it may not be entirely reflective of the health effects from exposure to air pollutants. Meteorological factors that are considered in the heat index (HI), temperature and relative humidity, are not considered when calculating the AQI. It may be important to consider certain meteorological factors when assessing the quality of the air because such factors affect the dynamics of air movement as well as the formation of certain pollutants.Through a series of Quasi-Poisson regression models, we investigated whether the relationship between the …

Autumn Tree Phenology In Northern Wisconsin: Humans Versus Photographs, Trevor Iglinski

Theses and Dissertations

Ecosystem primary productivity halts when plants go dormant, and so the timing of dormancy as it relates to autumn phenology has been a focus of much interdisciplinary research. While monitoring plant phenology has its roots in directly observing specimens, digital sensors along with modern methods have also become a mainstay in phenology. Results from different methods often vary, so there is still a need to better understand how digital cameras record autumn phenology, especially in comparison with ground-based observations (Keenan et al. 2014). This study compared autumn phenology derived from direct ground observations with upward-facing fisheye photography, in the context …

Cathodically Protected Steel Mesh As An Environmentally Friendly Material For Oyster Reef Restoration, Afanasy Melnikov

Theses and Dissertations

Plastic mesh is widely used in oyster reef restoration efforts worldwide, including the Indian River Lagoon (IRL) estuary in Florida. Plastic degrades overtime, releasing microplastics and nanoplastics particles into the environment and causing harm to the marine ecosystem. Thus, there is an ongoing need to find an alternative eco-friendly material. Cathodically protected steel, a possible alternate substrate for such restoration, involves an electrical current running through steel to create an impressed cathodic system. This results in the formation of chalk on the steel, similar to the limestone (calcium carbonate) base of reefs. A benefit of this process is that the …

Climate-Informed Prediction And Forecast Modeling Of Installation Total Energy Consumption, Scott C. Weiss

Theses and Dissertations

Climate variability is an external and stochastic factor that causes energy demand uncertainty. Energy managers can use climate-based models to understand future trends of energy demand and to adjust operations, policy, and budgets accordingly. This research focuses on 1) identifying how climate attributes impact energy use, 2) creating a historically informed statistical modeling framework to skillfully predict energy use, and 3) forecasting future changes to energy use and costs, using CMIP5 temperature projections, at the campus level. After synthesizing the existing breadth of research on climate-informed energy modeling, a skillful, unbiased, climate-informed total energy consumption prediction model is developed for …

Ccsfs/Ksc Total Lightning Warning Radii Optimization For Merlin Using Preexisting Lightning Areas, Kimberly G. Holland

Theses and Dissertations

The purpose of this research is to optimize lightning warning radii specifications for the 45th Space Wing (45 SW), thus reducing the number of unnecessary warnings that delay ground processing needed for space launch execution at Kennedy Space Center and Cape Canaveral Space Force Station. This thesis sought to answer two key research questions addressing: 1) What radius reduction effectively balances both safety and operations and do reduction recommendations from previous research align with results from the new detection system? 2) What insights can be gained from comparing measurement results for seasonal lightning events as well as lightning types? This …

Correction Of Back Trajectories Utilizing Machine Learning, Britta F. Gjermo Morrison

Theses and Dissertations

The goal of this work was to analyze 24-hour back trajectory performance from a global, low-resolution weather model compared to a high-resolution limited area weather model in particular meteorological regimes, or flow patterns using K-means clustering, an unsupervised machine learning technique. The duration of this study was from 2015-2019 for the contiguous United States (CONUS). Three different machine learning algorithms were tested to study the utility of these methods improving the performance of the CFS relative to the performance of the RAP. The aforementioned machine learning techniques are linear regression, Bayesian ridge regression, and random forest regression. These results mean …

Improving Airfield Pavement Degradation Prediction Skill With Local Climate And Traffic, Evan M. Fortney

Theses and Dissertations

Airfield pavements are a critical component of the global transportation network that provide a platform for national defense. Preventative and corrective maintenance activities are founded upon accurate expectations of degradation. The leading pavement management software creates degradation predictions from pavement groups using age as the IV and current state conditions as the DV. For this work, a framework is created and implemented that utilizes a PCR model to build upon accepted practices for degradation modeling to enhance and possibly augment future prediction capabilities. The model was applied to pairs of location and pavement family and reveals several findings: the selected …

Identifying Four Year Average Cloud Field Regimes From World Wide Merged Cloud Analysis Dataset By Way Of K-Means Clustering, Stewart G. Almeida

Theses and Dissertations

Joint histograms of cloud top height (CTH) and optical depth (OD) are created using the World-Wide Merged Cloud Analysis (WWMCA) dataset over a four year period (2014-2017) to identify average cloud field regimes and assess the application of utilizing the WWMCA dataset with the AFIT Sensor and Scene Emulation Tool (ASSET). Two selected regions encompassing the Florida peninsula and a portion of the Pacific Ocean off the west-central coast of South America are examined over the months of January and July. Cloud field regimes are identified by running generated hourly OD-CTH histograms through k-means clustering, with optimal cluster number ( …

Comparison Of Spatial Precipitation Forecasts With A Satellite Dataset, Andrew C. Siebels

Theses and Dissertations

The purpose of this research is to analyze and compare global precipitation data from the Climate Forecast System Version 2 (CFSv2) with the Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN)-Climate Data Record (CDR) to improve long term precipitation forecasting. The CFSv2 has a 0.5-degree resolution which will provide model data for precipitation forecasts. The PERSIANN-CDR is a satellite derived daily 0.25-degree dataset with 37 years of global precipitation coverage 60 N to 60 S. The 0-to-10, 15-to-25, 55-to-65, and 80-to-90 day forecast time frames will then be analyzed for accuracy, and a quantile mapping (QM) technique …