Oceanography and Atmospheric Sciences and Meteorology Commons^™

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.

2025 August 21 - Tennessee Weekly Drought Summary, Tennessee Climate Office, East Tennessee State University

Tennessee Climate Office Weekly Drought Summaries

No abstract provided.

Annual And Seasonal Mean Air Temperature Trends And Future Projections Over The Nile Delta, Egypt, Amna S. Dabbous, Dina M. Hendy, Yasser M. El-Wakeel, Tarek M. El-Geziry

Blue Economy

The Mediterranean air temperature has steadily increased during the last few decades. This shift affects ecological ecosystems and human activity. This study examined longterm air temperature trends in Alexandria and Port Said, using monthly data from 1957 to 2022 to assess the impact of climate change on these coastal cities, being the two extremities of the Nile Delta. Temperature records were analyzed using the Mann- Kendall test, a robust non-parametric statistical method for detecting trends in climatic data, and future projections were evaluated through the CMIP5 climate models under various RCP scenarios. Considerable warming trends were seen in the air …

New Precipitation Is Scarce In Deep Soils: Findings From 47 Forest Plots Spanning Switzerland, Emily I. Burt, Scott T. Allen, Sabine Braun, Simon Tresch, James W. Kirchner, Gregory R. Goldsmith

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

As precipitation infiltrates into soils, it can recharge them, displace previously stored waters, or bypass already-filled pores. Using 3,697 δ2H and δ18O measurements of water collected nearly monthly over >3 years in 47 forest plots across Switzerland, we present a systematic investigation of the controls on mobile soil water transport. We quantified the lags and damping of water as it percolates downward using young water fraction analysis (Fyw), and the fractions of soil water composed by precipitation that fell within the previous month (new water fractions, Fnew). The Fnew of water sampled in surface soils ranged …

The Future Intensification Of Hydrological Extremes And Whiplashes In The Contiguous United States Increase Community Vulnerability, Surendra Maharjan, Wenzhao Li, John D. Bolten, Hesham El-Askary

Mathematics, Physics, and Computer Science Faculty Articles and Research

Hydroclimatic whiplash rapid shifts between drought and flood poses growing risks to U.S. communities. Here, we assess historical extremes and future projections using a normalized streamflow metric: the annual mean flow’s deviation from the 1981–2020 average, expressed as a fraction of that average. This metric is applied to United States Geological Survey records and Localized Constructed Analogs downscaled projections under Representative Concentration Pathways 4.5 and 8.5. Results reveal sharp regional disparities, with drought deficits exceeding 300% of normal flow during multi-year droughts. By linking hydrologic outcomes with the Federal Emergency Management Agency’s National Risk Index, we find that counties facing …

Topological And Information-Theoretic Analysis Of Climate-Driven Indonesian Throughflow Dynamics, Sandy H. S. Herho, Katarina E.P. Herho, Iwan P. Anwar, Rusmawan Suwarman

Northeast Journal of Complex Systems (NEJCS)

The Indonesian Throughflow (ITF) represents the sole tropical pathway connecting Pacific and Indian Oceans, yet quantitative understanding of climate mode influences on its variability remains incomplete. We applied information-theoretic and topological frameworks to analyze 34 years (1984-2017) of observational ITF transport data alongside ENSO and IOD indices. Bootstrap analysis revealed pronounced ITF seasonality with 13.28 Sv amplitude peaking in September, contrasting with negligible climate index annual cycles, indicating scale separation in forcing mechanisms. Multi-method extrema detection identified 36-41 extreme events per variable, with 23.1% coincidence between ENSO and IOD high extrema confirming known co-occurrence patterns. Ensemble information-theoretic metrics demonstrated ENSO …

Mechanisms Of Gold Enrichment In Seafloor Massive Sulfide Deposits: A Study On The Higashi-Aogashima Hydrothermal Field, Claudia Martinez

UNLV Theses, Dissertations, Professional Papers, and Capstones

The study of Seafloor Massive Sulfides (SMS) deposit formation is vital for assessing both the economic potential and environmental risks posed by future marine mining projects. Metal-rich SMS deposits form in hydrothermal vent systems within tectonically active regions, such as back-arc basins, where faults enhance crustal permeability, enabling fluid migration driven by magmatic heat sources at depth in the crust. Currently our understanding of SMS formation processes is based on bulk-rock geochemical and isotopic data, lacking the necessary spatial and temporal resolution to understand ore forming processes. As a result, critical gaps remain in understanding the exact mechanisms responsible for …

Ocean And Coastal Acidification Monitoring Priorities For The Northeast Us And Eastern Canada, Christopher Hunt, Austin Pugh, Jake Kritzer, Samantha Siedlecki, Kumiko Azetsu-Scott, Parker Gassett, Diane Lavoie, Adam Pimenta, Amy Trice, Elizabeth Turner

Faculty Publications

The Interagency Working Group on Ocean Acidification Monitoring Prioritization Plan 2024 calls for Coastal Acidification Networks to identify the ocean and coastal acidification (OCA) monitoring needs most important for their regions. The Northeast Coastal Acidification Network (NECAN) organized a webinar series to study regional needs, which culminated with a workshop in November 2023. This workshop led to the identification of six priority new Monitoring Needs in addition to the maintenance of current monitoring efforts:

• Improve spatial and temporal scale of monitoring co-located OCA variables and biological measurements to better resolve variability of acidification dynamics in concert with biological processes …

2025 August 14 - Tennessee Weekly Drought Summary, Tennessee Climate Office, East Tennessee State University

Tennessee Climate Office Weekly Drought Summaries

No abstract provided.

Assessing The Costs Of Constructed Floating Wetlands For The Treatment Of Surface Waters And Wastewater, John Awad, Christopher Walker, Declan Page, Muhammad Arslan, Sarah A. White, Terry Lucke, Simon Beecham, Ryan J. Winston, William H.J. Stonsnider, Phil Nicodemus, Chris Streb, John Van Leeuwen

Faculty Publications

The development of constructed floating wetlands (CFWs) as a nature-based solution for water treatment has progressed over the last 25 years. However, full-scale CFW adoption remains relatively limited due in part to the uncertainty regarding the costs of CFWs in terms of capital and operational expenditure (CAPEX and OPEX) and treatment capacity. This study reports on the costs of 11 international CFW schemes including the factors affecting CAPEX and OPEX and levelized costs of nitrogen and phosphorus removal. The estimated levelized CAPEX and OPEX ranged from US$15/m² to $2537/m² and from $0.5/m² y⁻¹ to $181/m² y⁻¹, respectively, for CFW schemes …

The Effects Of Varying Temperatures And Food Availability On The Reproductive Output Of The Acorn Barnacle: Chthamalus Fissus, Karina L. Rog

McNair Summer Research Program

Climate change is predicted to intensify ocean warming and the reduction in phytoplankton abundance, potentially disrupting reproductive processes in filter-feeding intertidal invertebrates. This study investigated the combined effects of water temperature increases and food availability on the reproductive output on Chthamalus fissus, a dominant intertidal barnacle species found along the Southern California coastline. Using a controlled laboratory experiment, adult barnacles collected from the nearshore rocky intertidal habitat in La Jolla, California, were exposed to two temperature regimes (ambient water temperature ~ 18°C and elevated water temperature ~ 20-21°C) and two food concentration treatments (low and high phytoplankton and rotifer …

2025 August 7 - Tennessee Weekly Drought Summary, Tennessee Climate Office, East Tennessee State University

Tennessee Climate Office Weekly Drought Summaries

No abstract provided.

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 …

A 12,800-Year-Old Layer With Cometary Dust, Microspherules, And Platinum Anomaly Recorded In Multiple Cores From Baffin Bay, Christopher R. Moore, Vladimir A. Tselmovich, Malcolm A. Lecompte, Allen West, Stephen J. Culver, David J. Mallinson, Mohammed Baalousha M.Sc, Ph.D., James P. Kennett, William M. Napier, Michael Bizimis, Victor Adedeji, Seth R. Sutton, Gunther Kleteschka, Kurt A. Langworthy, Jesus P. Perez, Timothy Witwer, Marc D. Young, Jordan Jeffreys, Richard C. Greenwood, James A. Malley

Faculty Publications

The Younger Dryas Impact Hypothesis (YDIH) posits that ~12,800 years ago Earth encountered the debris stream of a disintegrating comet, triggering hemisphere-wide airbursts, atmospheric dust loading, and the deposition of a distinctive suite of extraterrestrial (ET) impact proxies at the Younger Dryas Boundary (YDB). Until now, evidence supporting this hypothesis has come only from terrestrial sediment and ice-core records. Here we report the first discovery of similar impact-related proxies in ocean sediments from four marine cores in Baffin Bay that span the YDB layer at water depths of 0.5–2.4 km, minimizing the potential for modern contamination. Using scanning electron microscopy …

A Deep Learning Framework With Explainable Ai For Atmospheric Blocking Detection And Interpretation, Devansh Khandelwal

Discovery Undergraduate Interdisciplinary Research Internship

Atmospheric blocking is a large-scale quasi-stationary phenomenon in mid-latitude circulation, characterized by persistent high-pressure systems that disrupt the typical west-to-east flow of the jet stream. These systems can cause extreme weather events—such as heatwaves, cold spells, or droughts—that persist for days or even weeks. This study proposes a deep learning framework to predict and interpret the occurrence of atmospheric blocking by integrating geophysical precursors such as geopotential height (Z500), stream function (SF200), and potential vorticity. These features, which are dynamically linked to blocking onset and persistence, serve as inputs to a Convolutional Neural Network model trained on the CESM Large …

Expanded Genetic And Functional Diversity Of Oceanic Fungi, Xuefeng Peng, David L. Valentine

Faculty Publications

Background

Fungi are known members of marine microbiomes that can act as saprotrophs, parasites, and pathogens. Although a few studies utilizing cultivation-based methods and metabarcoding have been conducted, the diversity, ecological roles, and functional activities of fungi in the open ocean remain vastly underexplored. This gap in knowledge is particularly notable in oxygen minimum zones (OMZ) of the ocean, which have expanded over the past 50 years, affecting marine ecosystems and biogeochemical cycles. The eastern tropical North Pacific Ocean (ETNP) is the largest oxygen minimum zone where fungi have been implicated in the production of the potent greenhouse gas nitrous …

Tree Rings And The Broader Ocean-Atmospheric Circulation In The Highland Himalayas, Sanjaya Bhandari

All-Inclusive List of Electronic Theses and Dissertations

Climate change has altered tree-growth patterns and resulted in higher sea-surface temperatures across the planet. The Himalayan biome is one of the most vulnerable areas in the world to climate change because it has caused changes in forests’ growth and glaciers’ retreat. Dendrochronology has been used to understand the impact of climate change on tree growth and for climate reconstruction. In this dissertation, I discuss the growth of trees in the highlands of the eastern, central, and western Himalayas for the last 500 years and relate these patterns to the present global warming scenario and broad-scale climate modes. I reconstructed …

2025 August - Tennessee Monthly Climate Report, Tennessee Climate Office, East Tennessee State University

Tennessee Climate Office Monthly Reports

No abstract provided.

Ocean-Ice Sheet Interactions During Super-Interglacial Mis 31: Comparison Of Rock Magnetic Records From The Scotia Sea (59.1°S) And Fram Strait (76.5°N), Olga Libman-Roshal

Theses, Dissertations and Culminating Projects

The mid-Pleistocene transition (MPT) was a period spanning ~1.2-0.7 Ma when glacial-interglacial cyclicity changed from 41 kyr obliquity paced to 100 kyr eccentricity paced cycles with increased glacial-interglacial contrast post-MPT. Marine Isotope Stage (MIS) 31 was a “super-interglacial” within the MPT and occurred in the recent geological past (1.08-1.06 Ma). During MIS 31, the tectonic configuration resembled the present day, but Earth’s orbital parameters were marked by maximum values of eccentricity and obliquity while atmospheric CO2 remained at pre-industrial levels (below 280 ppm). MIS 31 therefore offers a valuable baseline for testing the impacts of modern anthropogenic CO2 levels combined …

Simulation Of Photochemical Effects On Air Quality, Grace Li

Chemical Engineering Undergraduate Honors Theses

Nitrogen dioxide (NO₂) and ozone (O₃) are both EPA criteria air pollutants in the troposphere, largely generated by combustion and therefore present in significant concentrations in urban areas. Sunlight facilitates chemical reactions between pollutants and ambient air. Aerosols modulate the amount of available energy required to drive such photochemical reactions, ultimately impacting air quality. Simulating photolysis rates with FastJX software is a resource-efficient strategy to study how these aerosols can affect air quality.