Physical Sciences and Mathematics Commons^™

Whistler-Mode Waves In Magnetic Ducts, Anatoly V. Streltsov, Salman A. Nejad

Publications

Observations from the NASA MMS satellites show packages of ELF whistler-mode waves localized inside the small-scale irregularities of the magnetic field. These irregularities are formed by the narrow field-aligned channels where the magnitude of the background magnetic field inside the channel is greater or less than outside. By analogy with the classical density ducts, we introduce the high-B duct (HBD), where the magnitude of the field inside the channel is greater than the outside, and the low-B duct (LBD), where the magnitude of the field inside the channel is less than the outside. We investigate the guiding of the ELF …

Supporting Data For Figures In "Mixing Of The Connecticut River Plume During Ambient Flood Tides: Spatial Heterogeneity And Contributions Of Bottom-Generated And Interfacial Mixing", Michael M. Whitney

Department of Marine Sciences

This archive contains the supporting data for figures in the manuscript "Mixing of the Connecticut River plume during ambient flood tides: Spatial heterogeneity and contributions of bottom-generated and interfacial mixing" by Michael M. Whitney. The objectives of this modeling study are 1) characterizing the spatial heterogeneity of turbulent buoyancy fluxes, 2) partitioning turbulent buoyancy fluxes into bottom-generated and interfacial shear contributions, and 3) quantifying contributions to plume-integrated mixing within the tidal plume. Data are from the Regional Ocean Modeling System (ROMS) results for idealized model configurations. The Zip file (Figure_data.zip) contains MATLAB data files, which are named FigureXX_data.mat. Variable names …

Supporting Data For Figures In "Wind-Enhanced Separation Of Large-Scale River Plumes From Coastal Corners", Michael M. Whitney

Department of Marine Sciences

This archive contains the supporting data for figures in the manuscript "Wind-enhanced separation of large-scale river plumes from coastal corners" by Michael M. Whitney. This study analyzes idealized models to quantify how large-scale river plumes and wind-driven currents interact at perpendicular coastal corners. Data are from the Regional Ocean Modeling System (ROMS) results for idealized model configurations. The Zip file (Figure_data.zip) contains MATLAB data files, which are named FigureXX_data.mat. Variable names and units correspond to graphed data of each figure in manuscript. Full descriptions of research methods and results are included in manuscript.

2023 August 10 - Tennessee Weekly Drought Summary, Tennessee Climate Office, East Tennessee State University

Tennessee Climate Office Weekly Drought Summaries

No abstract provided.

2023 August 3 - Tennessee Weekly Drought Summary, Tennessee Climate Office, East Tennessee State University

Tennessee Climate Office Weekly Drought Summaries

No abstract provided.

Applications Of Artificial Intelligence To Improve Coastal Ocean Modeling, Dongliang Shen

Electronic Theses and Dissertations

Numerical Modeling (NM) is widely used to simulate and predict hydrodynamic processes and marine particle movements in coastal oceans, particularly during extreme weather events and emergencies. NM offers the capability to realistically simulate multiple state variables and fill gaps caused by scarce observations. However, inherent uncertainties exist in all NMs, primarily arising from the following three factors: 1) insufficient observations leading to uncertain model initial and boundary conditions, 2) inevitable truncation errors due to coarse model resolution, and 3) imperfect physics parameterization schemes for sub-grid processes, especially those related to waves. The consequences of these uncertainties are that 1) even …

Characteristics Of Refractivity And Sea State In The Marine Atmospheric Surface Layer And Their Influence On X-Band Propagation, Douglas Matthew Pastore

Electronic Theses and Dissertations

Predictions of environmental conditions within the marine atmospheric surface layer (MASL) are important to X-band radar system performance. Anomalous propagation occurs in conditions of non-standard atmospheric refractivity, driven by the virtually permanent presence of evaporation ducts (ED) in marine environments. Evaporation ducts are commonly characterized by the evaporation duct height (EDH), evaporation duct strength, and the gradients below the EDH, known as the evaporation duct curvature. Refractivity, and subsequent features, are estimated in the MASL primarily using four methods: in-situ measurements, numerical weather and surface layer modeling, boundary layer theory, and inversion methods.

The existing refractivity estimation techniques often assume …

Improving The Design And Conduct Of Aquatic Toxicity Studies With Oils Based On 20 Years Of Croserf Experience, Wa Stubblefield, M Barron, G Bragin, Me Delorenzo, B De Jourdan, B Echols, Dp French-Mccay, P Jackman, Jr Loughery, Tf Parkerton, D. Abigail Renegar, Jl Rodriguez-Gil

Marine & Environmental Sciences Faculty Articles

Laboratory toxicity testing is a key tool used in oil spill science, spill effects assessment, and mitigation strategy decisions to minimize environmental impacts. A major consideration in oil toxicity testing is how to replicate real-world spill conditions, oil types, weathering states, receptor organisms, and modifying environmental factors under laboratory conditions. Oils and petroleum-derived products are comprised of thousands of compounds with different physicochemical and toxicological properties, and this leads to challenges in conducting and interpreting oil toxicity studies. Experimental methods used to mix oils with aqueous test media have been shown to influence the aqueous-phase hydrocarbon composition and concentrations, hydrocarbon …

Precipitation Variability And Predictability Over The Arabian Peninsula, Central Southwest Asia, And Southern Africa, Matthew Francis Horan

Doctoral Dissertations

The Northern Hemisphere winter is the main rainy season for the Arabian Peninsula (AP), Central Southwest Asia (CSWA), and Southern Africa (SF), where precipitation predictability is limited or understudied. This dissertation research focuses on improving our understanding of these regions' wet-season precipitation characteristics and predictability.

First, I have identified the AP's key moisture sources through a Lagrangian back-trajectory algorithm. Mid-latitude land and water bodies, such as the Mediterranean and Caspian Seas, are the primary moisture sources in the northern region. Areas further south rely on moisture transport from the Western Indian Ocean and the African continent. A significant drying trend …

Decadal Climate Variability In Mesoscale-Resolving Coupled Models, Ilijana Mastilovic

Theses and Dissertations

Most of our knowledge about the causes of 20th-century climate change comes from simulation using numerical models. However, the observed climate variability and the one simulated by the state-of-the-art climate models exhibit substantial discrepancies at the decadal-to-multidecadal time scale and thus it hinders our fundamental understanding of the observed climate change. Evidence is mounting that vigorous intrinsic variability associated with mesoscale oceanic features contributes significantly to large-scale low-frequency climate variability, with fundamental implications for decadal climate low-frequency climate prediction. As of yet, extensive simulation of these decadal effects using high-resolution state-of-the-art coupled climate models has been computationally prohibitive, as it …

Unsupervised Machine Learning Of Tornado-Producing Storms In The Southeastern United States, Morgan R. Steckler

Masters Theses

The east-southeastern US is uniquely affected by storm and tornado-related damages, costs, injuries, and deaths. Based on doppler radar, satellite, and modeled data, previous research sought to understand these different types of storms that produce strong tornadoes. Many approaches to storm classification are time intensive, complex, and vary significantly across the literature. The purpose of this work is to (1) explore the radar-derived data structure and spread of strong tornado-producing mesoscale storms in the east-southeastern US; (2) use K-Means unsupervised machine learning methods to elucidate clusters (storm types) and clustering attributes; and (3) assess the utility of K-Means as a …

A Framework For Statistical Modeling Of Wind Speed And Wind Direction, Eva Murphy

All Dissertations

Atmospheric near surface wind speed and wind direction play an important role in many applications, ranging from air quality modeling, building design, wind turbine placement to climate change research. It is therefore crucial to accurately estimate the joint probability distribution of wind speed and direction. This dissertation aims to provide a modeling framework for studying the variation of wind speed and wind direction. To this end, three projects are conducted to address some of the key issues for modeling wind vectors.\\

First, a conditional decomposition approach is developed to model the joint distribution of wind speed and direction. Specifically, the …

2023 August - Tennessee Monthly Climate Report, Tennessee Climate Office, East Tennessee State University

Tennessee Climate Office Monthly Report

No abstract provided.

Ocean Wave-Coherent Temperature And Humidity Near-Surface Vertical Distributions And Their Effect On Radar Performance Over The Ocean, Mathew James Stanek

Electronic Theses and Dissertations

Large knowledge gaps concerning the effect of ocean surface waves on near-surface vertical distributions of temperature and humidity in the marine atmospheric surface layer exist due to practical limitations and sensor fidelity challenges of direct measurements. Wave effects on these distributions between the wave trough and crest are least studied within the literature. These scalar distributions influence atmospheric refractivity, which can lead to anomalous propagation of electromagnetic energy. Measurements of temperature and humidity are classically made using rocket- or radiosondes and fixed weather stations, and can utilize tethered profiling systems. However, these measurement systems have limitations when obtaining measurements near …

A Preliminary Characterization And Assessment Of Mesophotic Octocoral Microbiomes In The Western Gulf Of Mexico, Edward P. Gniffke

Theses and Dissertations

Mesophotic Coral Ecosystems are highly diverse and productive ecosystems in the western Gulf of Mexico which are composed of, in part, by octocorals (subclass Octocorallia). Despite their importance as foundational organisms octocorals are an understudied group in this region, with little known about their microbial community. Ninety-eight Octocoral samples collected from the western and northwestern Gulf of Mexico were sequenced using 16S rRNA sequencing to characterize their microbial communities. The sequenced microbiomes were generally low in diversity composed of a few core microbial taxa. Octocoral group was the main driver of microbiome composition as opposed to depth, season, region, and …

Investigation Of The Flow Field In The Jack Rabbit Ii Mock Urban Environment Field Tests Using A 1:50 Scale Wind Tunnel Model, Paulo Victor De Freitas Lopes

Graduate Theses and Dissertations

Accidental release of toxic chemicals can put workers and nearby populations at significant risk. Consequence assessment of accidents in urban environments is of particular interest. Urban geometries create wind channels between buildings, along with particularly dangerous areas downwind of buildings, where near-stagnant flow is present. Furthermore, recirculation zones can be formed between buildings, trapping high concentrations of toxic gases at ground level, particularly for denser-than-air gases. In 2015, the Department of Homeland Security conducted the Jack Rabbit II Field Test (JR-II) at Dugway Proving Ground, UT. During JR-II, chlorine was released at the center of a Mock Urban Environment (MUE) …

Hydrological Dynamics Of Surface-Groundwater Interactions Between Major Springs Of Mammoth Cave And The Green River, Kentucky, Usa, Matthew Cecil

Masters Theses & Specialist Projects

Mammoth Cave is an iconic example of the cave and karst systems that underlie over 50% of the United States and provide around 13% of the world’s population with water resources. These environmental features are vulnerable to drought, pollution, and human impacts. The complex hydrological regime of the Mammoth Cave system has been studied in the past, but there are improvements and updates that can be made to the past research. The dynamics of the surface-groundwater system, particularly reversals of the Green River and how it backfloods into the cave, are some examples. Echo River and River Styx Springs provide …

Nitrogen Cycling In The Lower Chesapeake Bay And Mid- And South Atlantic Bight, Yifan Zhu

OES Theses and Dissertations

Nitrogen (N) is central to marine primary production; its availability often limits the capacity and rates of primary productivity in most of the world’s oceans. Contrastingly, estuaries frequently receive anthropogenic N loading, oftentimes resulting in eutrophication, harmful algal blooms (HABs), and substantially degraded water quality. Nutrient variability in both estuaries and oceanic regimes results from meteorological forcing and physical processes, including wind-induced, tidal, and mesoscale mixing and upwelling. In this dissertation, a comprehensive investigation of N variability and cycling and its links to physical-biogeochemical processes was conducted using time-series monitoring approaches, flux estimations, satellite imaging, biogeochemical measurements, and molecular analyses. …

A Comparative Study Of Vinti-Based Orbit Propagation And Estimation For Cubesats In Very Low Earth Orbits, Ethan Michael Senecal

Mechanical & Aerospace Engineering Theses & Dissertations

In recent years, there has been a growing interest in CubeSats and very low Earth orbit (VLEO) space missions. Mission SeaLion, a collaborative CubeSat mission between Old Dominion University, the U.S. Coast Guard Academy, and U.S. Air Force Institute of Technology, planned to launch a 3U CubeSat into VLEO. The VLEO mission is a particularly challenging environment for navigation and orbit propagation because drag introduces a significant perturbation for orbit models such as SGP4. Additionally, mission requirements left no capacity for attitude determination or control, further reducing knowledge of drag behavior of the satellite in flight. This deficiency is a …

History Of Ice-Rafting In The Arctic Ocean During Glacial Maxima Through Marine Isotope Stage 6, Shannon M. Cofield

OES Theses and Dissertations

Numerous studies attempted to reconstruct Arctic paleoclimate, specifically ice mass timing and locations, during glacial maxima. While some regions, like the Barents-Svalbard Ice Sheet (BSIS) are well-studied, they may benefit from a high-resolution paleo proxy. Other regions are highly contested, such as the East Siberian Sea or the presence of a central Arctic Ocean ice mass.

This research uses an Fe-grain provenance method to (1) define how the BSIS behaved during Marine Isotope Stage (MIS) 2, 4, and 6, and when it retreated; (2) determine the presence and ages of Shelf Ice Masses (SIMs) in the Beaufort Sea and East …

Tidal Flooding In The Mid-Atlantic Region Of The Us: Water Quality Effects In The Lower Chesapeake Bay, Alfonso Macias Tapia

OES Theses and Dissertations

Many coastal areas around the globe suffer from nutrient pollution and its environmental, social, and economic consequences. Nutrient inputs can come from point (e.g., the end of a pipe) and nonpoint sources, from which the former are better constrained as sampling need only be conducted at a discharge point. Given the temporal and spatially extensive nature of tidal flooding events, they can represent another type of nonpoint source of nutrients to adjacent water bodies heretofore, unexamined and quantified. Most studies examining impacts of tidal flooding have focused on threats to resources on land, such as urban infrastructure and human health …

Effect Of Morphology And An Upstream Tall Building On A Street Canyon Flow, Haoran Du

Electronic Thesis and Dissertation Repository

The effects of the morphological model and the existence of an upstream tall building on the turbulent street canyon flow and the overlying boundary layer are investigated in a wind tunnel, using Stereoscopic Particle Image Velocimetry (S-PIV) measurements. The velocity variances, Reynolds shear stress, and turbulent kinetic energy are found to be larger than in a similar idealized street canyon model. Increasing building height results in a decrease in vertical mass fluxes across the opening of the canyon, at least in the canyon portion directly downstream of the building. The interaction between the large-scale structures in the overlying boundary layer …

Diurnal Variations Of Meteorological Elements To Fluctuation Of Air Quality Parameters, Wandayantolis Wandayantolis, Firda Amalia Maslakah, Sugeng Nugroho

Journal of Environmental Science and Sustainable Development

Many studies have shown the relationship between meteorological elements and air quality. However, some aspects of the relationship are unknown, particularly in Indonesia, which has a variety of topographical landscapes and climatic conditions. This study seeks to define the relationship between meteorological variables and the diurnal pattern of three pollutants that contributes to the so-called Indeks Standard Pencemar Udara (ISPU), similar to the Air Quality Index (AQI), in a remote area in Bukit Kototabang, West Sumatra, Indonesia. The three parameters, namely Particulate Matter 10 micrometers (PM10), carbon monoxide (CO), and tropospheric ozone (O₃), were correlated with diurnal variations …

Crustal Structures Of Diebold Knoll And Adjacent Juan De Fuca Oceanic Crust From Integration Of Seismic, Gravity And Magnetic Data, Md Ariful Islam

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Cascadia Subduction Zone (CSZ) has a long history of devastating earthquakes as the Juan de Fuca plate subducts beneath North America, where an imminent megathrust earthquake is expected. Compared to other subduction zones, CSZ exhibits unusually low seismic activity, particularly in the central region with respect to relatively high seismicity zones to the north and south. Some researchers attribute this behavior to subducted seamounts, although their impact on seismicity remains poorly understood and highly debated in the literature. Examining subducted seamounts is challenging due to complexity of the overburden strata. That is why this study focuses on an isolated not-yet-subducted …

Fun Azores: A Functional Trait Database For The Meio-, Macro-, And Megafauna From The Azores Marine Park (Mid-Atlantic Ridge), Neus Campanyà-Llovet, Amanda E. Bates, Daphne Cuvelier, Eva Giacomello, Diana Catarino, Andrew J. Gooday, Björn Berning, Blanca Figuerola, Manuel A. E. Malaquias, Carlos J. Moura, Joana R. Xavier, Tracey Sutton, Laurence Fauconnet, Sofia P. Ramalho, Bárbara De Moura Neves, Gui M. Machado, Tammy Horton, Andrey V. Gebruk, Kirill Minin, Joël Bried, Tina Molodtsova, Mónica A. Silva, Anna Dilman, Antonina Kremenetskaia, Eudriano F. S. Costa, Jameson Clarke, Helen R. Martins, Christopher K. Pham, Marina Carreiro-Silva, Ana Colaço

Marine & Environmental Sciences Faculty Articles

Trait-based approaches that complement taxonomy-based studies have increased in popularity among the scientific community over the last decades. The collection of biological and ecological characteristics of species (i.e., traits) provides insight into species and ecosystem vulnerability to environmental and anthropogenic changes, as well as ecosystem functioning. Here, we present the FUN Azores trait database, describe our approach, evaluate its scope, compare it to other marine trait databases, and explore the spatial distribution of its traits with “functional maps.” While most of the available trait databases to date contain essential information to understand the functional diversity of a taxonomic or functional …

2023 July 27 - Tennessee Weekly Drought Summary, Tennessee Climate Office, East Tennessee State University

Tennessee Climate Office Weekly Drought Summaries

No abstract provided.

The Impact Of Climate Change On Selected Pnw Watersheds Through The Lens Of Western Red Cedar Habitat, Jordan T. Hamann

Dissertations and Theses

Climate change is a real phenomenon that is exacerbating existing natural processes and developing into a new normal for the planet. This change may be devastating for Pacific Northwest populations of Western Red Cedar (WRC) west of the Cascade Mountain range in the states of Oregon and Washington. WRC is a valuable tree species for reasons both economic and cultural. Dieback among WRC is following an accelerating trend. Since dieback is usually followed by tree mortality, understanding its causes and distribution is beneficial to the overall success of the species going into the future.

Through the use of ESRI's ArcGIS …

2023 July 20 - Tennessee Weekly Drought Summary, Tennessee Climate Office, East Tennessee State University

Tennessee Climate Office Weekly Drought Summaries

No abstract provided.

Integrated Observation And Research On Climate And Environment From Boundary Layer To Middle And Upper Levels Of Atmosphere, Xiang’Ao Xia, Yufang Tian, Yunfei Wu, Jing Yang, Dongsheng Ji, Jinqiang Zhang, Renjian Zhang, Pucai Wang, Hongbin Chen, Xiushu Qie, Daren Lü

Bulletin of Chinese Academy of Sciences (Chinese Version)

After more than 50 years of development, the Xianghe station (XH), Institute of Atmospheric Physics, Chinese Academy of Sciences, has been equipped with comprehensive detection capabilities covering from the boundary layer to the middle and upper levels of the atmosphere. As one of the few atmospheric integrated field scientific test stations in the world, XH has joined a number of important networks. Many large international field campaigns have been carried out. Long-term continuous observation data are widely used to study exchange of energy and mass in the middle and upper atmosphere, atmospheric physical chemistry and air quality in the boundary …

Xianghe Integrated Observatory Of Climate And Environment, Institute Of Atmospheric Physics, Chinese Academy Of Sciences

Bulletin of Chinese Academy of Sciences (Chinese Version)

No abstract provided.