Oceanography and Atmospheric Sciences and Meteorology Commons^™

Why Was There A Harmful Algal Bloom In 2015: The Relative Growth Of Toxic And Non-Toxic Diatoms As A Function Of Temperature, Ariana M. Jensen, Meagan P. Beley-Finnemore, Christopher E. Ikeda, William P. Cochlan

STAR Program Research Presentations

A coastwide bloom of the toxigenic diatom Pseudo-nitzschia in 2015 resulted in the largest recorded outbreak and unprecedented levels of the neurotoxin, domoic acid (DA), along the North American west coast. The scientific community has suggested that warmer ocean temperatures were the main cause of this harmful algal bloom (HAB), but little scientific evidence to support the relationship between temperature, and the growth and toxicity of Pseudo-nitzschia has been provided for local isolates of these diatoms. To gain insight into bloom dynamics, a laboratory study was conducted to examine the growth of toxic and non-toxic phytoplankton species at a range …

Estimation Of The Instantaneous Downward Surface Shortwave Radiation Using Modis Data In Lhasa For All-Sky Conditions, Xu Lu

Sustainability and Social Justice

Measuring the solar irradiance with high accuracy is the basis of PV power forecasting. Although the downward surface shortwave radiation (DSSR) data derived from satellite images are widely used in the PV industry, the instantaneity and accuracy of these data are not suitable for PV power forecasting in a short-time period. In this study, an algorithm to calculate instantaneous DSSR for all-sky conditions was developed by combining clear-sky radiative transfer model and 3D radiative transfer model using MODIS products (MOD03-07, 09). The algorithm was evaluated by ground measurements from a station in Lhasa and a reference dataset from FLASHFlux. The …

Optical Water Quality And Human Perceptions Of Rivers, Amie West

Graduate Theses and Dissertations

Understanding water quality dynamics in recreational rivers is integral in shaping management strategies that maintain ecosystem health, perceived value and appeal, and regional economic significance in a changing environment. Optical water quality describes the behavior of light in water as governed by its physical and chemical composition, and is among the strongest influences on human perceptions of water quality. Ethnohydrology is the study of culturally constructed knowledge and understanding of water. This work is the culmination of an interdisciplinary approach to water resources research—integrating optical water quality and ethnohydrology methods to recognize the intersection between measured water quality and visible …

Agro-Climatic Change, Crop Production And Mitigation Strategies-Case Studies In Arkansas, Usa And Kenya, John Westley Magugu

Graduate Theses and Dissertations

Although climate change impacts vary geographically and temporally, studies at local levels are not readily available for stakeholders to better understand how their local communities would be affected and what remedial measures could be more effective in their local contexts. This dissertation has examined climate change and its impacts in two different local contexts: eastern Arkansas in the USA and Nyando in Kenya. The first part of this dissertation develops agro-meteorological indicators and examines the relationship between agro-meteorological indicators and crop yields in eastern Arkansas between 1960 and 2014. Results reveal that temperature based indicators were more strongly correlated to …

Fish Communities Associated With Cold-Water Corals Vary With Depth And Substratum Type, Rosanna Milligan, Gemma Spence, J. Murray Roberts, David M. Bailey

Marine & Environmental Sciences Faculty Articles

Understanding the processes that drive the distribution patterns of organisms and the scales over which these processes operate are vital when considering the effective management of species with high commercial or conservation value. In the deep sea, the importance of scleractinian cold-water corals (CWCs) to fish has been the focus of several studies but their role remains unclear. We propose this may be due to the confounding effects of multiple drivers operating over multiple spatial scales. The aims of this study were to investigate the role of CWCs in shaping fish community structure and individual species-habitat associations across four spatial …

A Tribute To Thomas M. Church: Exploring Chemical Oceanography In The Coastal Zone-The History And Future, Gregory A. Cutter, David J. Burdige

OES Faculty Publications

(First paragraph) One can find different historical perspectives on the development of studying the chemistry of oceans as well as names for this study—marine chemistry, chemistry of the sea, marine aquatic chemistry, marine biogeochemistry, or chemical oceanography. It could be argued that chemical oceanography is the most inclusive for an earth science since oceanography itself is an integrated discipline that links the biology, chemistry, geology, and physics together. Regardless of the name, perhaps the first intensive, modern/post-nineteenth century study of the ocean’s chemistry was the GEOSECS Program from ca. 1970–1978. The significance of GEOSECS was that it examined the chemistry …

Revisiting The Problem Of The Gulf Stream Separation: On The Representation Of Topography In Ocean Models With Different Types Of Vertical Grids, Tal Ezer

CCPO Publications

The difficulty of simulating a realistic Gulf Stream (GS) that separates from the coast at Cape Hatteras has troubled numerical ocean modelers for a long time, and the problem is evident in different models, from the early models of the 1980s to the modern models of today. The source of the problem is not completely understood yet, since GS simulations are sensitive to many different factors, such as numerical parameterization, model grid, treatment of topography and forcing fields. A curious result of early models is that models with terrain-following vertical grids (e.g., “sigma” or “s” coordinates) seem to achieve a …

Flow Scales Of Influence On The Settling Velocities Of Particles With Varying Characteristics, Corrine N. Jacobs, Wilmot Merchant, Marek Jendrassak, Varavut Limpasuvan, Roi Gurka, Erin E. Hackett

Marine Science

The settling velocities of natural, synthetic, and industrial particles were measured in a grid turbulence facility using optical measurement techniques. Particle image velocimetry and 2D particle tracking were used to measure the instantaneous velocities of the flow and the particles' trajectories simultaneously.We find that for particles examined in this study (Rep = 0.4-123), settling velocity is either enhanced or unchanged relative to stagnant flow for the range of investigated turbulence conditions. The smallest particles' normalized settling velocities exhibited the most consistent trends when plotted versus the Kolmogorov-based Stokes numbers suggesting that the dissipative scales influence their dynamics. In contrast, the …

Tsunami Warning System, Amay Vijay Desai

Doctoral Dissertations and Master's Theses

The effects of a tsunami on a coastline can be devastating. In an attempt to mitigate the damages caused by tsunamis, and to provide coastal communities with evacuation alerts, it is essential to have early warning systems installed offshore. Tsunami early warning systems can detect the formation of tsunami waves long before they reach shore, providing coastal communities with information about the strength of an incoming tsunami.

Since providing accurate information about oceanic wave patterns is absolutely necessary to forecast the magnitude of a tsunami as it forms, the focus of this research is to develop a novel approach which …

Determining The Viability Of Recent Storms As Modern Analogues For North-Central Gulf Of Mexico Paleotempestology Through Sedimentary Analysis And Storm Surge Reconstruction, Joshua Caleb Bregy

Master's Theses

The northern Gulf of Mexico has been devastated by recent intense storms. Camille (1969) and Katrina (2005) are two notable hurricanes that made landfall in virtually the same location in Mississippi. However, fully understanding the risks and processes associated with hurricane impacts is impeded by a short and fragmented instrumental record. Paleotempestology could potentially use modern analogues from intense storms in this region to extend the hurricane record back to pre-observational time. Existing empirically based models can back-calculate surge heights over coastal systems as a function of transport distance, particle settling velocity, and gravitational acceleration. We collected cores in a …

Chlorine Demand Shows Thresholds And Hierarchy With Source Water Quality At Beaver Lake, Arkansas, Jaime M. Gile

Graduate Theses and Dissertations

This study investigated the effects of source water quality in Beaver Lake on the amount of chlorine (Cl) needed to develop decision support system to help guide chlorination practices in pre-treatment of source water. Chlorine demand assays were performed on water samples from Beaver Lake collected from the intake structure at Beaver Water District from March 2014 through August 2015, and using data from these assays, the two points of interest in this study were the Cl dose at which Cl residuals began to accumulate and the mean Cl demand occurring after that dose. Three methods of analysis were used …

Is The Detection Of Accelerated Sea Level Rise Imminent?, J. T. Fasullo, R. S. Nerem, B. Hamlington

CCPO Publications

Global mean sea level rise estimated from satellite altimetry provides a strong constraint on climate variability and change and is expected to accelerate as the rates of both ocean warming and cryospheric mass loss increase over time. In stark contrast to this expectation however, current altimeter products show the rate of sea level rise to have decreased from the first to second decades of the altimeter era. Here, a combined analysis of altimeter data and specially designed climate model simulations shows the 1991 eruption of Mt Pinatubo to likely have masked the acceleration that would have otherwise occurred. This masking …

Stream Microbial Communities As Potential Indicators Of River And Landscape Disturbance In North-Central Arkansas, Wilson Howard Johnson

Graduate Theses and Dissertations

In the past decade, 29 shale basins have been actively developed across 20 states for extraction of natural gas (NG) via horizontal drilling/hydraulic fracturing (=fracking). This includes ~5000 wells within the Fayetteville shale of north-central Arkansas. Development often impacts both river- and landscapes, and management requires catchment-level evaluations over time, with organismal presence/absence as indicators. For this study next-generation sequencing was used to identify/characterize microbial communities within biofilm of eight Arkansas River tributaries, so as to gauge potential catchment influences. Streams spanned a gradient of landscape features and hydrological flows, with four serving as ‘potentially impacted catchment zones’ (PICZ) and …

Trend Analysis Of Water Quality In Northwest Arkansas Streams Reflects Changes In The Watershed, Zachary Paul Simpson

Graduate Theses and Dissertations

Watershed export of nutrients, sediments, and chemicals impacts receiving waters. Changes within the watershed (e.g., anthropogenic or climatic) can alter the transport of constituents in streams. Stream monitoring is crucial for understanding these effects. This study developed a potential improvement to flow-adjusting constituent concentrations in streams, an important step of analyzing monitoring data in lotic systems for trends. The method incorporates a K-fold cross-validation procedure to optimize a model explaining the relationship between the concentration and streamflow, thus providing a valuable tool to researchers in water quality. Additionally, two case studies were conducted on watersheds located in northwest Arkansas using …

Evolutionary Potential Of A Dispersal-Restricted Species In Response To Climate Change, Lorena Torres Martinez

Open Access Dissertations

Habitat replacement and fragmentation associated with projected climate change pose a critical threat to global biodiversity. Edaphically limited plant species with restricted dispersal abilities will be especially handicapped to track their optimal climate spatially. Instead, the persistence of these species will depend on their capacity to adapt in situ to novel climate regimes. Here I evaluated the evolutionary potential of Lasthenia fremontii, an annual plant species restricted to ephemeral wetlands called vernal pools in California to adapt to the projected patterns of climate change. Across L. fremontii distribution there is a latitudinal gradient in precipitation which, combined with reduced …

Tornado Density And Return Periods In The Southeastern United States: Communicating Risk And Vulnerability At The Regional And State Levels, Michelle Bradburn

Electronic Theses and Dissertations

Tornado intensity and impacts vary drastically across space, thus spatial and statistical analyses were used to identify patterns of tornado severity in the Southeastern United States and to assess the vulnerability and estimated recurrence of tornadic activity. Records from the Storm Prediction Center's tornado database (1950-2014) were used to estimate kernel density to identify areas of high and low tornado frequency at both the regional- and state-scales. Return periods (2-year, 5-year, 10-year, 25-year, 50-year, and 100-year) were calculated at both scales as well using a composite score that included EF-scale magnitude, injury counts, and fatality counts. Results showed that the …

Biogeochemistry Of A Saline, Alkaline, Terminal Lake Ecosystem In Transition; Walker Lake, Nevada, Katherine Lynn Willever

UNLV Theses, Dissertations, Professional Papers, and Capstones

Walker Lake is a saline, alkaline, terminal lake ecosystem located in west-central Nevada. For over one hundred years, anthropogenic streamflow diversions within the Walker River Basin have ultimately led to little or no water reaching Walker Lake, the basin’s terminus for water flow. These diversions have resulted in a >46 meter decrease in the lake surface altitude and increases in salinity and dissolved salt constituents that have caused the elimination of native fish species. This study examines how the lack of freshwater inflow has altered the physical, chemical, and microbiological structure of Walker Lake during the lake’s ongoing desiccation.

Between …

Wind Climatology: A Study Of Trends On Rodgers' Dry Lakebed, Dana Coppernoll-Houston

STAR Program Research Presentations

A number of smaller projects at the Armstrong Flight Research Center fly on or close to the ground and are subject to ground-level winds. Many of these are new prototype models, such as PRANDTL-D (Preliminary Research Aerodynamic Design to Lower Drag). Waiting for the right conditions on a day of variable winds can sometimes mean that teams fail to complete testing. A strategic analysis of wind behavior at a locations where winds can vary greatly due to terrain could lend insight into the best times to test for near-ground aircraft. The purpose of this project was to data mine historical …

Evaluating A Measure-Calculate Method For Determining Sediment Oxygen Demand In Lakes, Adrian Beirise

Graduate Theses and Dissertations

A steady-state mass diffusion model used with simple measurable and calculable inputs for determining sediment oxygen demand (SOD) is compared to an intact core incubation (ICI) SOD method using samples from three lakes. The mass diffusion model coupled with inputs is known as the measure-calculate method (M-C) and is a potential alternative to existing methods for measuring SOD which are more complex, time-consuming, and costly. The M-C method requires inputs for volumetric sediment oxygen uptake (Ṅsed), sediment density and porosity, and water properties. Ṅsed was determined by suspending sediment in oxygen-saturated water with a DO probe and determining the steady …

Electrodeionization Versus Electrodialysis: A Clean-Up Of Produced Water In Hydraulic Fracturing, Brigitte Marie Rodgers

Graduate Theses and Dissertations

Electrodeionization (EDI) is a widely studied process ranging from applications in wastewater clean-up in the food and beverage industry to purifying organic compounds. To date, there are no apparent studies on applying this technology to produced wastewater recovered from hydraulic fracking sites. Water consumption within hydraulic fracturing sites can reach in the upwards of millions of gallons per site, so a need for a water recycling process becomes necessary within areas where water requirements are scarce. Implementation of an EDI module that is capable of handling high salt solutions from produced wastewater in subsequent fracturing practices will decrease overall water …

The Impact Of Climate Change In Bangladesh On The Rice Market And Farm Households, Mst Ashrafun Nahar

Graduate Theses and Dissertations

Bangladesh is trying to achieve self-sufficiency in domestic rice production but climate change effects on agricultural production makes it challenging to attain the goal. The country is highly vulnerable to the effects of climate change since it is the major cause to rise in sea level, more warm summer, and happening food and cyclone in the country.

This study develops an Aggregate Farm Household Model to analyze the impact of potential land loss and yield reduction from climate change on production, consumption, prices, welfare, and the ability of government to achieve self-sufficiency in rice production. The model is calibrated to …

Elevation Data And Mapping Updates, Doug Marcy

July 29, 2016: The Latest in Sea Level Rise Science

No abstract provided.

Street Level Predictive Modeling Of Nuisance Flooding In Norfolk, Va, Jon Derek Loftis, Harry V. Wang, David R. Forrest, William 'Skip' A. Stiles

July 29, 2016: The Latest in Sea Level Rise Science

No abstract provided.

Noaa Inundation Dashboard, Audra Luscher, Paul Fanelli

July 29, 2016: The Latest in Sea Level Rise Science

No abstract provided.

The Science Of Sea Level Rise And The Impact Of The Gulf Stream, Tal Ezer

July 29, 2016: The Latest in Sea Level Rise Science

No abstract provided.

Risk Of Extreme Events, Don Resio

July 29, 2016: The Latest in Sea Level Rise Science

No abstract provided.

Subsidence Monitoring In Hampton Roads Using Satellites, Ben Hamlington

July 29, 2016: The Latest in Sea Level Rise Science

No abstract provided.

Agenda, Hr Adaptation Forum

July 29, 2016: The Latest in Sea Level Rise Science

No abstract provided.

Total Water Level And Wave Run Up Forecast, Eric Seymour

July 29, 2016: The Latest in Sea Level Rise Science

No abstract provided.

Coral Persistence To Ocean Warming Via Developmental Acclimation, Heather L. Schaneen

HCNSO Student Theses and Dissertations

Scleractinian corals are the ‘engineers’ of tropical coral reef ecosystems. Their three-dimensional structure provides habitat for thousands of fish and invertebrate species. The persistence of corals is threatened by climate change. In this study I investigated if corals may be able to increase tolerance to ocean warming through developmental acclimation, i.e. if corals that experience warmer temperatures during embryonic and larval development are better able to cope with higher temperatures later in life. Larvae of the broadcast spawning coral Montastraea cavernosa were raised at ambient (29°C) and future projected ocean warming temperatures (+2°C, 31°C). After larval settlement, coral juveniles from …