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Articles 3511 - 3540 of 13989

Full-Text Articles in Oceanography and Atmospheric Sciences and Meteorology

Development Of Novel Instrumentation And Methods To Investigate The Composition And Phase Partitioning Of Semivolatile And Intermediately Volatile Organic Compounds In Atmospheric Organic Aerosol, Claire Fortenberry May 2020

Development Of Novel Instrumentation And Methods To Investigate The Composition And Phase Partitioning Of Semivolatile And Intermediately Volatile Organic Compounds In Atmospheric Organic Aerosol, Claire Fortenberry

McKelvey School of Engineering Graduate Student Theses & Dissertations

Atmospheric particulate matter (PM) is ubiquitous in both indoor and outdoor air and is generally detrimental to human health. PM composed of particles with aerodynamic diameters less than 2.5 um (PM2.5) are related to adverse health outcomes including heart disease and respiratory disease. Fundamentally, particle physical properties such as size and hygroscopicity are dictated by chemical composition, which can be highly complex, particularly for organic aerosol (OA). In both outdoor and indoor air, OA is composed substantially of intermediately volatile and semivolatile organic compounds (I/SVOCs), which exist in both gas and particle phases under typical atmospheric conditions. The distribution of …


Soil Microbes Trade-Off Biogeochemical Cycling For Stress Tolerance Traits In Response To Year-Round Climate Change, Maria O. Garcia, Pamela H. Templer, Patrick O. Sorensen, Rebecca Sanders-Demott, Peter M. Groffman, Jennifer M. Bhatnagar May 2020

Soil Microbes Trade-Off Biogeochemical Cycling For Stress Tolerance Traits In Response To Year-Round Climate Change, Maria O. Garcia, Pamela H. Templer, Patrick O. Sorensen, Rebecca Sanders-Demott, Peter M. Groffman, Jennifer M. Bhatnagar

Advanced Science Research Center

Winter air temperatures are rising faster than summer air temperatures in high-latitude forests, increasing the frequency of soil freeze/thaw events in winter. To determine how climate warming and soil freeze/thaw cycles affect soil microbial communities and the ecosystem processes they drive, we leveraged the Climate Change across Seasons Experiment (CCASE) at the Hubbard Brook Experimental Forest in the northeastern United States, where replicate field plots receive one of three climate treatments: warming (+5°C above ambient in the growing season), warming in the growing season + winter freeze/thaw cycles (+5°C above ambient +4 freeze/thaw cycles during winter), and no treatment. Soil …


Molecular Properties Are A Primary Control On The Microbial Utilization Of Dissolved Organic Matter In The Ocean, Yuan Shen, Ronald Benner May 2020

Molecular Properties Are A Primary Control On The Microbial Utilization Of Dissolved Organic Matter In The Ocean, Yuan Shen, Ronald Benner

Faculty Publications

The global ocean sequesters a large amount of reduced carbon in dissolved organic molecules that can persist for centuries to millennia. The persistence of dissolved organic carbon (DOC) in the deep ocean has been attributed to inherently refractory molecules and to low concentrations of molecules, but the relative roles of molecular properties and molecular concentrations remain uncertain. We investigate both of these possibilities using bioas-say experiments with unfiltered seawater collected from five depths (50–1500 m) at the Bermuda Atlantic Time-Series Study site. The microbial utilization of compositionally distinct forms of seawater DOC at in situ and elevated concentrations was determined. …


Massive Peatland Carbon Banks Vulnerable To Rising Temperatures, A. M. Hopple, R. M. Wilson, M. Kolton, Cassandra A. Zalman, J. P. Chanton, J. Kostka, P. J. Hanson, Jason K. Keller, S. D. Bridgham May 2020

Massive Peatland Carbon Banks Vulnerable To Rising Temperatures, A. M. Hopple, R. M. Wilson, M. Kolton, Cassandra A. Zalman, J. P. Chanton, J. Kostka, P. J. Hanson, Jason K. Keller, S. D. Bridgham

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Peatlands contain one-third of the world’s soil carbon (C). If destabilized, decomposition of this vast C bank could accelerate climate warming; however, the likelihood of this outcome remains unknown. Here, we examine peatland C stability through five years of whole-ecosystem warming and two years of elevated atmospheric carbon dioxide concentrations (eCO2). Warming exponentially increased methane (CH4) emissions and enhanced CH4 production rates throughout the entire soil profile; although surface CH4 production rates remain much greater than those at depth. Additionally, older deeper C sources played a larger role in decomposition following prolonged warming. Most …


What Is The Limiting Nutrient In Winter In Urban Reservoirs? A Case Study, Precious Nyabami May 2020

What Is The Limiting Nutrient In Winter In Urban Reservoirs? A Case Study, Precious Nyabami

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

The importance of reservoirs in widely acknowledged by urban population, yet little is understood scientifically about their ability to process nutrients deposited into them in winter. Nutrients in waste water, lawns and construction runoff are deposited into reservoirs and several ecosystem services are lost which leads to what several researchers call “the urban syndrome”. Some studies have been done on the winter limnology of lakes, yet little is understood about the same process in reservoirs. To fill this missing knowledge gap, a study on one of Nebraska’s lakes (Holmes’ lake) was done. In this study, we simulated how phosphorus, nitrogen …


Erratum: Charles G. Messing (2020) A Revision Of The Unusual Feather Star Genus Atopocrinus With A Description Of A New Species (Echinodermata: Crinoidea). Zootaxa, 4731: 471–491., Charles G. Messing May 2020

Erratum: Charles G. Messing (2020) A Revision Of The Unusual Feather Star Genus Atopocrinus With A Description Of A New Species (Echinodermata: Crinoidea). Zootaxa, 4731: 471–491., Charles G. Messing

Marine & Environmental Sciences Faculty Articles

Erratum.


Synergistic Use Of Remote Sensing And Modeling For Estimating Net Primary Productivity In The Red Sea With Vgpm, Eppley-Vgpm, And Cbpm Models Intercomparison, Wenzhao Li, Surya Prakash Tiwari, Hesham El-Askary, Mohamed Ali Qurban, Vassilis Amiridis, K. P. Manikandan, Michael J. Garay, Olga V. Kalashnikova, Thomas C. Piechota, Daniele C. Struppa May 2020

Synergistic Use Of Remote Sensing And Modeling For Estimating Net Primary Productivity In The Red Sea With Vgpm, Eppley-Vgpm, And Cbpm Models Intercomparison, Wenzhao Li, Surya Prakash Tiwari, Hesham El-Askary, Mohamed Ali Qurban, Vassilis Amiridis, K. P. Manikandan, Michael J. Garay, Olga V. Kalashnikova, Thomas C. Piechota, Daniele C. Struppa

Mathematics, Physics, and Computer Science Faculty Articles and Research

Primary productivity (PP) has been recently investigated using remote sensing-based models over quite limited geographical areas of the Red Sea. This work sheds light on how phytoplankton and primary production would react to the effects of global warming in the extreme environment of the Red Sea and, hence, illuminates how similar regions may behave in the context of climate variability. study focuses on using satellite observations to conduct an intercomparison of three net primary production (NPP) models--the vertically generalized production model (VGPM), the Eppley-VGPM, and the carbon-based production model (CbPM)--produced over the Red Sea domain for the 1998-2018 time period. …


Law School News: Dennis W. Nixon: Doctor Of Laws, Honoris Causa 05-09-2020, Roger Williams University School Of Law May 2020

Law School News: Dennis W. Nixon: Doctor Of Laws, Honoris Causa 05-09-2020, Roger Williams University School Of Law

Life of the Law School (1993- )

No abstract provided.


Estimating Global Mean Sea-Level Rise And Its Uncertainties By 2100 And 2300 From An Expert Survey, Benjamin P. Horton, Nicole S. Khan, Niamh Cahill, Janice S.H. Lee, Timothy A. Shaw, Andra J. Garner, Andrew C. Kemp, Simon E. Engelhart, Stefan Rahmstorf May 2020

Estimating Global Mean Sea-Level Rise And Its Uncertainties By 2100 And 2300 From An Expert Survey, Benjamin P. Horton, Nicole S. Khan, Niamh Cahill, Janice S.H. Lee, Timothy A. Shaw, Andra J. Garner, Andrew C. Kemp, Simon E. Engelhart, Stefan Rahmstorf

School of Earth & Environment Departmental Research

Sea-level rise projections and knowledge of their uncertainties are vital to make informed mitigation and adaptation decisions. To elicit projections from members of the scientific community regarding future global mean sea-level (GMSL) rise, we repeated a survey originally conducted five years ago. Under Representative Concentration Pathway (RCP) 2.6, 106 experts projected a likely (central 66% probability) GMSL rise of 0.30–0.65 m by 2100, and 0.54–2.15 m by 2300, relative to 1986–2005. Under RCP 8.5, the same experts projected a likely GMSL rise of 0.63–1.32 m by 2100, and 1.67–5.61 m by 2300. Expert projections for 2100 are similar to those …


Refining Interpretations Of A Deglacial Record In Gulf Of Mexico Marine Sediment Cores Using Foraminifera C-14 Dates And Multi-Proxy Sediment Analyses, Lindsey R. Monito May 2020

Refining Interpretations Of A Deglacial Record In Gulf Of Mexico Marine Sediment Cores Using Foraminifera C-14 Dates And Multi-Proxy Sediment Analyses, Lindsey R. Monito

Senior Honors Projects, 2020-current

The upper fourteen sections of three cores recovered from the International Marine Past Global Changes Study (IMAGES) VIII/Paleoceanography of the Atlantic and Geochemistry (PAGE) 127 expedition of 2002, are stratigraphic records of the climate and provenance variations that influenced sediment deposition in the Gulf of Mexico during the Pleistocene and Holocene. Though originally cored by the USGS for gas hydrate investigations, cores MD02-2535, MD02-2555, and MD02-2560 have been repurposed for undergraduate course-based paleoclimate research at JMU. Shipboard interpretations of the color reflectance data for these cores suggested that two dark stratigraphic intervals present in all of the cores were regional …


Lightning Activity In The Continental United States On An Enso Time Scale, 2002-2015, Tyler M. Gingrich May 2020

Lightning Activity In The Continental United States On An Enso Time Scale, 2002-2015, Tyler M. Gingrich

Senior Honors Projects, 2020-current

This investigation examined the frequency and spatial pattern of lightning in the continental United States from 2002 to 2015. Before analysis, flashes were grouped based on their El Niño Southern Oscillation (ENSO) phase and Spatial Synoptic Classification (SSC) type for the winter season (December, January, and February). The purpose of this study is to better understand the relationship between planetary teleconnections, synoptic scale air masses, and micro scale phenomena, specifically lightning, in the continental United States. Evidence suggests ENSO cold phase flashes tend to have a lower frequency in number of flashes and flash days, as well as a northward …


Fine-Scale Coral Connectivity Pathways In The Florida Reef Tract: Implications For Conservation And Restoration, Charles Frys, Antoine Saint-Amand, Matthieu Le Henaff, Joana Figueiredo, Alyson Kuba, Brian K. Walker, Jonathan Lambrechts, Valentin Vallaeys, David Vincent, Emmanuel Hanert May 2020

Fine-Scale Coral Connectivity Pathways In The Florida Reef Tract: Implications For Conservation And Restoration, Charles Frys, Antoine Saint-Amand, Matthieu Le Henaff, Joana Figueiredo, Alyson Kuba, Brian K. Walker, Jonathan Lambrechts, Valentin Vallaeys, David Vincent, Emmanuel Hanert

Marine & Environmental Sciences Faculty Articles

Connectivity between coral reefs is critical to ensure their resilience and persistence against disturbances. It is driven by ocean currents, which often have very complex patterns within reef systems. Only biophysical models that simulate both the fine-scale details of ocean currents and the life-history traits of larvae transported by these currents can help to estimate connectivity in large reef systems. Here we use the unstructured-mesh coastal ocean model SLIM that locally achieves a spatial resolution of ~100 m, 10 times finer than existing models, over the entire Florida Reef Tract (FRT). It allows us to simulate larval dispersal between the …


Survivorship And Growth In Staghorn Coral (Acropora Cervicornis) Outplanting Projects In The Florida Keys National Marine Sanctuary, Matt Ware, Eliza N. Garfield, Ken Nedimyer, Jessica Levy, Les Kaufman, William F. Precht, R. Scott Winters, Steven Miller May 2020

Survivorship And Growth In Staghorn Coral (Acropora Cervicornis) Outplanting Projects In The Florida Keys National Marine Sanctuary, Matt Ware, Eliza N. Garfield, Ken Nedimyer, Jessica Levy, Les Kaufman, William F. Precht, R. Scott Winters, Steven Miller

Marine & Environmental Sciences Faculty Articles

Significant population declines in Acropora cervicornis and A. palmata began in the 1970s and now exceed over 90%. The losses were caused by a combination of coral disease and bleaching, with possible contributions from other stressors, including pollution and predation. Reproduction in the wild by fragment regeneration and sexual recruitment is inadequate to offset population declines. Starting in 2007, the Coral Restoration Foundation™ evaluated the feasibility of outplanting A. cervicornis colonies to reefs in the Florida Keys to restore populations at sites where the species was previously abundant. Reported here are the results of 20 coral outplanting projects …


The Role Of Bacterial Symbionts And Bioluminescence In The Pyrosome, Pyrosoma Atlanticum, Alexis Berger May 2020

The Role Of Bacterial Symbionts And Bioluminescence In The Pyrosome, Pyrosoma Atlanticum, Alexis Berger

HCNSO Student Theses and Dissertations

The pelagic tunicate, Pyrosoma atlanticum, is known for its brilliant bioluminescence, but the mechanism causing this bioluminescence has not been fully characterized. This study identifies the bacterial bioluminescent symbionts of P. atlanticum collected in the northern Gulf of Mexico using various methods such as electron microscopy, light microscopy, and molecular genetics. The bacteria are localized within a specific pyrosome light organ. Bioluminescent symbiotic bacteria of Vibrionaceae composed >50% of taxa in tunicate samples (n=13), which was shown by utilizing current molecular genetics methodologies. While searching for bacterial lux genes in 2 tunicate samples, we also serendipitously generated a draft …


Weather And Climate Summary And Forecast: May 2020 Report, Gregory V. Jones May 2020

Weather And Climate Summary And Forecast: May 2020 Report, Gregory V. Jones

Linfield University Wine Studies Reports

This report provides a summary of the weather and climate forecast for May 2020. It includes forecast information specific to the Pacific Northwest and the western United States, as well as forecast information for other portions of the United States and abroad.


Symbiosis And Bioinvasive Dynamics Of Durusdinium Trenchii And Its Acroporid Coral Hosts, David Craig Lawson May 2020

Symbiosis And Bioinvasive Dynamics Of Durusdinium Trenchii And Its Acroporid Coral Hosts, David Craig Lawson

HCNSO Student Capstones

Biological invasions are a growing threat to coral reef ecosystems, as increasing anthropogenic transport and changing environmental patterns allow invasive species to establish and spread. Durusdinium trenchii is a dinoflagellate that has invaded the Greater Caribbean reef system and established symbioses with coral hosts. Establishment and persistence of invasive endosymbionts like D. trenchii could indicate a shift in the clade composition of coral holobionts worldwide. Statistical analyses were performed on the GeoSymbio database (Franklin et al. 2012) to determine whether differences in clade composition have occurred over time. Factors that influence biological invasions in marine ecosystems were assessed and analogous …


Intersections Of Climate Justice, Brigid Mark, Alejandra Gallardo, Jack Pieper, Danielle Voss, Corrie Grosse, Leonardo Cumplido, Elena Lozano May 2020

Intersections Of Climate Justice, Brigid Mark, Alejandra Gallardo, Jack Pieper, Danielle Voss, Corrie Grosse, Leonardo Cumplido, Elena Lozano

Environmental Studies Faculty Publications

This packet covers current information on climate justice issues in Minnesota including: Latinx immigration, public health, Black Lives Matter, native rights, LGBTQIA+ community, Somali livelihoods, and just transition.

We hope to help realize how we are connected to the climate crisis, identify action items for individuals, and build an understanding of how the crisis may affect our neighbors with different experiences. We believe that exchanging knowledge and raising awareness of local issues are essential to build a lasting and welcoming movement to secure healthy and happy livelihoods for all.


Building Adaptive Capacity In Tribal Communities Of The Missouri River Basin To Manage Drought And Climate Extremes: A Case Study From The Wind River Indian Reservation, Crystal J. Stiles, Natalie Umphlett, Mitch Cottenoir May 2020

Building Adaptive Capacity In Tribal Communities Of The Missouri River Basin To Manage Drought And Climate Extremes: A Case Study From The Wind River Indian Reservation, Crystal J. Stiles, Natalie Umphlett, Mitch Cottenoir

High Plains Regional Climate Center: Staff Publications

Native American peoples of the Northern and Central Plains have long endured harsh climate conditions, such as floods and droughts, and they possess valuable traditional knowledges that have enhanced their resilience to these extreme events. However, in recent times, limited capacity to adapt to a rapidly changing climate combined with a lack of resources have increased tribes’ vulnerability to climate extremes and their associated impacts. In response, a number of projects have been developed to assist tribes with their self-identified climate- and drought-related needs, particularly in the context of on-reservation decision-making. In this case study, we present an engagement strategy …


Critical Habitats And Biodiversity: Inventory, Thresholds And Governance, Alex Rogers, Octavio Aburto-Oropeza, Ward Appeltans, Jorge Assis, Lisa T. Ballance, Philippe Cury, Carlos M. Duarte, Fabio Favoretto, Joy Kumagai, Catherine Lovelock, Patricia Miloslavich, Aidi Niamir, David Obura, Bethan C. O'Leary, Gabriel Reygondeau, Callum Roberts, Yvonne Sadovy, Tracey Sutton, Derek P. Tittensor, Enriqueta Velarde May 2020

Critical Habitats And Biodiversity: Inventory, Thresholds And Governance, Alex Rogers, Octavio Aburto-Oropeza, Ward Appeltans, Jorge Assis, Lisa T. Ballance, Philippe Cury, Carlos M. Duarte, Fabio Favoretto, Joy Kumagai, Catherine Lovelock, Patricia Miloslavich, Aidi Niamir, David Obura, Bethan C. O'Leary, Gabriel Reygondeau, Callum Roberts, Yvonne Sadovy, Tracey Sutton, Derek P. Tittensor, Enriqueta Velarde

Marine & Environmental Sciences Faculty Reports

Key Messages:

  • Evidence suggests that ocean biodiversity at all levels is being lost as a result of the direct and indirect impacts of human pressures. The main drivers of biodiversity loss are overexploitation and human pressures in coastal environments (development, habitat loss, pollution, disturbance). Increasingly, climate change and ocean acidification are and will be drivers of biodiversity loss especially in sensitive coastal ecosystems.

  • Despite advances in understanding the distribution of species and habitats in the ocean, many aspects of marine biodiversity remain poorly understood. As a result, changes in marine biodiversity are difficult to ascertain and there is a critical …


The Microscopic Threat With A Macroscopic Impact: Microplastics Along The Southeast Florida Reef Tract, Emma Wightman May 2020

The Microscopic Threat With A Macroscopic Impact: Microplastics Along The Southeast Florida Reef Tract, Emma Wightman

HCNSO Student Theses and Dissertations

Microplastics have been found in large quantities in marine water samples and biota around the world. These microplastics, when present in the marine environment, decrease water quality and negatively impact marine life. This research quantified and classified marine plastic pollution along the Southeast Florida Reef Tract (SEFRT), in order to understand how this plastic is entering the ocean and the scope of the microplastic contamination in the northern SEFRT. Surface and bottom water samples were collected at 7 sites along the SEFRT for 6 months, filtered, and microscopically analyzed for microplastic content and composition using Fourier-transform infrared spectrophotometry (FTIR). Classification …


Statistical Comparisons Of Temperature Variance And Kinetic Energy In Global Ocean Models And Observations: Results From Mesoscale To Internal Wave Frequencies, Conrad A. Luecke, Brian K. Arbic, James G. Richman, Jay F. Shriver, Matthew H. Alford, Joseph K. Ansong, Steven L. Bassette, Maarten C. Buijsman, Dimitris Menemenlis, Robert B. Scott, Patrick G. Timko, Gunnar Voet, Alan J. Wallcraft, Luis Zamudio May 2020

Statistical Comparisons Of Temperature Variance And Kinetic Energy In Global Ocean Models And Observations: Results From Mesoscale To Internal Wave Frequencies, Conrad A. Luecke, Brian K. Arbic, James G. Richman, Jay F. Shriver, Matthew H. Alford, Joseph K. Ansong, Steven L. Bassette, Maarten C. Buijsman, Dimitris Menemenlis, Robert B. Scott, Patrick G. Timko, Gunnar Voet, Alan J. Wallcraft, Luis Zamudio

Faculty Publications

©2020. American Geophysical Union. All Rights Reserved. Temperature variance and kinetic energy (KE) from two global simulations of the HYbrid Coordinate Ocean Model (HYCOM; 1/12° and 1/25°) and three global simulations of the Massachusetts Institute of Technology general circulation model (MITgcm; 1/12°, 1/24°, and 1/48°), all of which are forced by atmospheric fields and the astronomical tidal potential, are compared with temperature variance and KE from a database of about 2,000 moored historical observations (MHOs). The variances are computed across frequencies ranging from supertidal, dominated by the internal gravity wave continuum, to subtidal, dominated by currents and mesoscale eddies. The …


Microplastic Prevalence In Four Oregon Rivers Along A Rural To Urban Gradient Applying A Cost-Effective Validation Technique, Amy Valine, Ashley Peterson, Dorothy Horn, Kaegan M. Scully‐Engelmeyer, Elise F. Granek May 2020

Microplastic Prevalence In Four Oregon Rivers Along A Rural To Urban Gradient Applying A Cost-Effective Validation Technique, Amy Valine, Ashley Peterson, Dorothy Horn, Kaegan M. Scully‐Engelmeyer, Elise F. Granek

Environmental Science and Management Faculty Publications and Presentations

Microplastics are ubiquitous in our environment and are found in rivers, streams, oceans, and even tap water. Riverine microplastics are relatively understudied compared to those in marine ecosystems. In Oregon, we sampled eight sites along four freshwater rivers spanning rural to urban areas to quantify microplastics. Plankton tow samples from sites along the Columbia, Willamette, Deschutes, and Rogue Rivers were analyzed using traditional light microscopy for initial microplastic counts. Application of Nile Red dye to validate microplastics improved microplastic identification, particularly for particles (Wilcox Test; p‐value=0.001). Nile Red‐corrected microfiber abundance was correlated with human population within five kilometers of the …


The Rapid Weakening Of Hurricane Fred (2009), Christina Talamo May 2020

The Rapid Weakening Of Hurricane Fred (2009), Christina Talamo

Atmospheric & Environmental Sciences

This research project discusses the rapid weakening of Hurricane Fred, a major Category 3 hurricane that occurred in the Atlantic basin during the 2009 Atlantic hurricane season. Between the days of 9 September and 13 September, Fred remained stationary off the coast of Africa in the Atlantic Ocean and never made landfall, all the while consistently weakening over open ocean from a major Category 3 hurricane to a tropical storm. In the Atlantic basin, I will define the rapid weakening, or RW, of a tropical cyclone as a decrease in the storm’s maximum sustained winds by 10.3 m s⁻¹ in …


Examining Terrain Effects On Upstate New York Tornado Events Utilizing High-Resolution Model Simulations, Luke Lebel May 2020

Examining Terrain Effects On Upstate New York Tornado Events Utilizing High-Resolution Model Simulations, Luke Lebel

Atmospheric & Environmental Sciences

The region at the intersection of the Mohawk and Hudson valleys of New York is characterized by complex terrain. It has been hypothesized that this complex terrain may have an impact on the development and evolution of severe convection in the region. Specifically, previous research has hypothesized that terrain-channeled flow in the Hudson and Mohawk valleys contributed to increased low-level wind shear and instability in the valleys during past severe weather outbreaks. However, a lack of observations in the region prevented this hypothesis from being robustly tested.

The goal of this study is to further examine this hypothesis and complement …


High-Resolution Simulation Of A Tornado In Bangladesh On 13 May 1996, Katherine Hollinger May 2020

High-Resolution Simulation Of A Tornado In Bangladesh On 13 May 1996, Katherine Hollinger

Atmospheric & Environmental Sciences

The country of Bangladesh has been known to experience some of the deadliest tornado outbreaks in the world. The severe weather season in this region only spans from late March to early May, but can produce significant severe weather outbreaks in that short time. Even with these outbreaks occurring, there has not been extensive analysis completed to evaluate the environmental parameters on these tornado event days in this region.

The goal of this project is to use a Weather Research and Forecasting (WRF) model simulation to evaluate a significant tornado that occurred in the Tangail and Jamalpur districts in Bangladesh …


The Release, Transport, And Utilization Of Phosphorus From Bed-Sediments: A Study Of A Eutrophic Littoral Cove On Beaver Lake In Northwest Arkansas, James A. Mccarty May 2020

The Release, Transport, And Utilization Of Phosphorus From Bed-Sediments: A Study Of A Eutrophic Littoral Cove On Beaver Lake In Northwest Arkansas, James A. Mccarty

Graduate Theses and Dissertations

Eutrophication of surface waters not only impacts the environment but also water treatment processes, the most significant of which is from the effects of algae. During peak algal growth in many southern U.S. reservoirs, inflows that bring nutrients are at an annual minimum, and phosphorus released from bed-sediments is trapped in the hypolimnion. Littoral areas, described as the most productive zone of the lake, may be a possible source of phosphorus that fuels algal growth in the reservoir. I studied an isolated shallow cove in the War Eagle Creek arm of Beaver Lake in Northwest Arkansas to measure, quantify, and …


Climate From The Mcmurdo Dry Valleys, Antarctica, 1986–2017: Surface Air Temperature Trends And Redefined Summer Season, Maciej K. Obryk, Peter T. Doran, Andrew G. Fountain, M. Myers, Christopher P. Mckay May 2020

Climate From The Mcmurdo Dry Valleys, Antarctica, 1986–2017: Surface Air Temperature Trends And Redefined Summer Season, Maciej K. Obryk, Peter T. Doran, Andrew G. Fountain, M. Myers, Christopher P. Mckay

Geology Faculty Publications and Presentations

The weather of the McMurdo Dry Valleys, Antarctica, the largest ice‐free region of the Antarctica, has been continuously monitored since 1985 with currently 14 operational meteorological stations distributed throughout the valleys. Because climate is based on a 30‐year record of weather, this is the first study to truly define the contemporary climate of the McMurdo Dry Valleys. Mean air temperature and solar radiation based on all stations were −20°C and 102 Wm−2, respectively. Depending on the site location, the mean annual air temperatures on the valleys floors ranged between −15°C and −30°C, and mean annual solar radiation varied …


Geochemical Tracers Of Arctic Ocean Processes: A Study Of Gallium, Barium, And Vanadium, Laura M. Whitmore May 2020

Geochemical Tracers Of Arctic Ocean Processes: A Study Of Gallium, Barium, And Vanadium, Laura M. Whitmore

Dissertations

The Arctic Ocean is linked to the global oceans and climate through its connectivity with the North Atlantic Ocean and the regional thermohaline deep water formation sites. It’s also a region undergoing rapid environmental change. To inform the community of potential changes in geochemical and biogeochemical cycles, this dissertation addresses three dissolved geochemical tracers (gallium, barium, and vanadium) as indicators of Arctic Ocean processes. Gallium is tested as a replacement for nutrient-type tracers in an effort to deconvolve Pacific and Atlantic derived waters in the Arctic Ocean basins. These water masses carry different heat and salt content and can influence …


Analyzing The Effects Of Of Seasonal Land Cover And Precipitation On The Sediment Delivery Ratio Of An Agriculture Dominated Watershed., Jonah Liebman May 2020

Analyzing The Effects Of Of Seasonal Land Cover And Precipitation On The Sediment Delivery Ratio Of An Agriculture Dominated Watershed., Jonah Liebman

Electronic Theses and Dissertations

Soil erosion is of escalating importance as increasing population and climate change have put increasing pressures on agricultural food production. Vegetation and precipitation are two factors that control the amount of soil erosion extant within a region. Sediment delivery ratios (SDRs) assess the ratio of soil eroded from a watershed system that is permanently removed from the system through stream sediment discharge. Using 1) river discharge and sediment concentration data and 2) the Revised Universal Soil Loss Equation (RUSLE), this thesis analyzes fluctuations in monthly SDRs for an average hydroclimatological crop-harvest season for the Senachwine Creek watershed, IL. Through calculating …


Machine Learning Modeling Of Horizontal Photovoltaics Using Weather And Location Data, Christil Pasion, Torrey J. Wagner, Clay Koschnick, Steven J. Schuldt, Jada B. Williams, Kevin Hallinan May 2020

Machine Learning Modeling Of Horizontal Photovoltaics Using Weather And Location Data, Christil Pasion, Torrey J. Wagner, Clay Koschnick, Steven J. Schuldt, Jada B. Williams, Kevin Hallinan

Faculty Publications

Solar energy is a key renewable energy source; however, its intermittent nature and potential for use in distributed systems make power prediction an important aspect of grid integration. This research analyzed a variety of machine learning techniques to predict power output for horizontal solar panels using 14 months of data collected from 12 northern-hemisphere locations. We performed our data collection and analysis in the absence of irradiation data—an approach not commonly found in prior literature. Using latitude, month, hour, ambient temperature, pressure, humidity, wind speed, and cloud ceiling as independent variables, a distributed random forest regression algorithm modeled the combined …