Master of Science (M.S.), University of Dayton, 2024, Aerospace Engineering

This research introduces an Origami-inspired dynamic spacecraft radiator, capable of adjusting heat rejection in response to orbital variations and extreme temperature fluctuations in lunar environments. The research centers around the square twist origami tessellation, an adaptable geometric structure with significant potential for revolutionizing radiative heat control in space. The investigative involves simulations of square twist origami tessellation panels using vector math and algebra. This study examines both a two-dimensional (2- D), infinitely thin tessellation, and a three-dimensional (3-D), rigidly-foldable tessellation, each characterized by an adjustable closure or actuation angle “φ”. Meticulously analyzed the heat loss characteristics of both the 2D and 3D radiators over a 180-degree range of actuation. Utilizing Monte Carlo Ray Tracing and the concept of “view factors”, the study quantifies radiative heat loss, exploring the interplay of emitted, interrupted, and escaped rays as the geometry adapts to various positions. This method allowed for an in-depth understanding of the changing radiative heat loss behavior as the tessellation actuates from fully closed to fully deployed. The findings reveal a significant divergence between the 2D and 3D square twist origami radiators. With an emissivity of 1, the 3D model demonstrated a slower decrease in the ratio of escaped to emitted rays (Ψ) as the closure/actuation angle increased, while the 2D model exhibited a more linear decline. This divergence underscores the superior radiative heat loss control capabilities of the 2D square twist origami geometry, offering a promising turndown ratio of 4.42, validating the model's efficiency and practicality for radiative heat loss control. Further exploration involved both non-rigidly and rigidly foldable radiator models. The non-rigidly foldable geometry, initially a theoretical concept, is realized through 3D modeling and physica (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2023, Materials Science and Engineering

Rising concerns related to fuel consumption and greenhouse emissions are being addressed by the automotive industry through vehicle lightweighting. Hence to meet the stringent requirements for lightweighting, conventional steel body parts are being replaced with Al alloys, Mg alloys and composite materials. However, the use of dissimilar materials together poses a serious threat of galvanic corrosion leading to accelerated degradation of galvanically coupled body parts. Aiming to develop the automotive closure panels using carbon fiber reinforced plastics (CFRP) inner and an outer aluminum alloy sheet to replace what is now an all-steel design, corrosion studies are performed to determine effective qualification of materials. In the first part of this project, CFRP materials of two types, named as twill and random, coupled with aluminum alloys (AA) 6111 and 6022 in all combinations, are subjected to a Ford laboratory accelerated cyclic corrosion test (CETP: 00.00-L-467) and on-road testing with the help of OSU campus buses for a year. The ability of the laboratory accelerated test to predict the on-road corrosion behavior is assessed by comparing the material volume loss determined using optical profilometer, microscopic images of corroded regions, and measurements of galvanic currents of the coupons exposed to the cyclic test. Analysis of the test results indicated that the coupon combination AA6111 and CFRP-random exhibits the highest corrosion susceptibility whereas AA6022 coupled with CFRP-twill is least susceptible to galvanic corrosion among the combinations used in this study. In the second part of the study, electrochemical behavioral differences between CFRP-twill and -random contributing to the differences in activities when coupled to AA6xxx are evaluated. For this, a copper deposition technique was developed to quantify the extent of electrochemical activity and identify the exact location of electrochemically active sites on the CFRP. Optimization (open full item for complete abstract)

Master of Science (MS), Ohio University, 2022, Chemical Engineering (Engineering and Technology)

Methane, the second largest greenhouse gas, is often released as a fugitive emission from natural gas drilling sites commonly located in rural, sparsely populated areas. At this level satellites lack the necessary spatial resolution to identify methane emissions, and site by site ground-based monitoring is economically unsustainable. To reconcile these issues, implementing aerial remote sensing platforms have recently been investigated. In this study a low altitude aircraft retrofitted with a shortwave infrared (SWIR), non-imaging spectrometer was used to locate methane leaks and estimate methane concentrations from active natural gas producing regions and natural gas infrastructures in Eastern Ohio. Three separate monitoring flights were completed on July 3rd, 2018, October 18th, 2018 and May 8th, 2019. Pairing flight data with MODTRAN6 radiative modeling, multiple concentration heat maps displaying flight path and estimated methane concentration were constructed. From these maps there was shown to be elevated methane concentrations in multiple regions: Proctor and Wheeling, West Virginia, Piedmont Lake, Ohio and an area of Eastern Ohio densely populated with actively producing horizontally drilled natural gas wells. There was also shown to be elevated methane concentrations at several specific locations: the Athens-Hocking Reclamation Center, a natural gas compressor station, a natural gas processing facility, and a surface mining site.

Master of Fine Arts, The Ohio State University, 2022, Art

This thesis paper is in correlation with the making and result of two projects named: My Hands, Your Eyes, Your Hands, Your Eyes and Broken Objects. Both projects are connected to a site and object determined process that values an open and conditional art practice. They locate themselves in the conditions of working with spaces, materials and objects that may be discarded or unnoticed as a way of reimagining of what we regard as important. This thesis paper describes the installation of My Hands Your Eyes, Your Hands, Your Eyes which was included in the 2022 Master of Fine Arts thesis exhibition that occurred from February 15th to March 19th at Urban Arts Space in Columbus Ohio. This project explores the differences and ambiguities of art, design and architecture with a phenomenological and experiential installation using light, space, and reflection. It also reflects on the craft oriented and contemplative material processes of laminating cardboard, stained glasswork, and neon bending. Included are a selection of writings and photographs from Broken Objects, an on-going project where I solicit and mend objects for others. This project began by thinking about the cycle of disposal in my object making practice. It has grown into a collection of unique correspondences between myself and project participants that center around their objects in need of mending and the stories they generate. Both projects work to re-invent artistic modes and ways of making by reinvigorating objects, spaces, and conditions. I value the knowledge gained through working with one's hands by way of craft materials and processes. These projects create opportunities to work in craft and studio practices while focusing on communal and shared experiences.

Master of Science (MS), Wright State University, 2021, Pharmacology and Toxicology

The functions of Ataxia telangiectasia and Rad-3 related protein (ATR) is very much important in a cell, as it is a DNA damage response protein, which plays an important role in cell division, DNA repair and apoptosis. This protein helps in proliferation in the actively DNA dividing normal cells and in cancer cells. The functions of ATR in a proliferating cell are well studied and known to involve regulation of replication fork and cell cycle progression after DNA damage. Whereas, in a non-replicating cell, the functions of ATR are not so well known. In the human body, most of the cells are in a non-replicating state, which do not actively replicate DNA, and include cells in a quiescent, senescent, and terminally differentiated state. What could be the function of ATR in these cells is something that nobody has ever looked at and is important because differentiated cells are routinely exposed to DNA damaging agents. ATR inhibitors are used as combination treatments in DNA damage-based anti-cancer therapies to inhibit pro-survival functions of ATR in cancer cells. Some of the studies show that, inhibition of ATR in non-diving cells would show an opposite effect than in the diving cells in response to DNA Damage caused by UVB. Hence, we have conducted experiments to test if inhibition of ATR would show a pro-survival role in differentiated keratinocytes. DNA damage has been induced using UV-B radiation and ATR is activated in both differentiated N-TERT keratinocytes in vitro and in human skin.

Bachelor of Sciences, Ohio University, 2021, Geography

To prepare for disaster mitigation and preparation, individual counties need to understand their risk for severe weather—specifically tornadoes, hail, and winds events. Weather forecasters have multiple tools at their disposal to predict severe weather events. These tools include radar, satellite, upper air observations, surface observations, and numerical weather models. (i.e., NAM, GFS, RAP, EURO, HRRR, etc.) All of these tools put together can give us a full picture of what the atmosphere is doing from the surface to the upper levels. Factoring in climatological data, we can start to understand patterns and predict when severe weather events will occur. Knowing this can offer a unique insight to the public of potential dangers corresponding with their location. This study examines climatological data from NCEI storm data reports for tornadoes, wind, and hail across the state of Ohio from January 1st, 1950 to May 31st 2020. Statistics, bar graphs, and GIS spatial representation were used to investigate the spatial distribution of storm events and the impact those events had on life and property. The storm mode of the parent thunderstorms associated with the severe reports was identified for events from 2010 to 2020. Results indicate that there have been more confirmed tornadoes in W and N OH than in SE OH. Most events with hail under 2 inches in diameter occurred in NE OH near Cleveland; however, hail over 2 inches is sporadically spaced across the state. Winds events both over and under 65 knots occurred most often in the northern part of the state—specifically, Lorain, Cuyahoga, and Lake counties. For parent storm modes, MCSs, and QLCSs were most responsible for tornado reports across the state.

Master of Science (M.S.), University of Dayton, 2021, Electro-Optics

This research project compares the performance of a Monolithic Optical Receiver and a Multi Aperture Receiver, in order to reduce optical power fluctuations induced by a Gaussian beam traveling through atmospheric turbulence. In this this work a mathematical model to describe the effects of focal spot wander and aperture averaging is provided, in order to explain the reduction of scintillation by increasing the area of an optical receiver. In particular, the Churnside model is used due to its simplicity to describe the effect of aperture averaging as a function of the collection diameter for receiving optical systems. In other hand, the steps for the alignment of Multi Aperture Receiver systems are shown. In this section, interferometric tests are used to align each aperture of this optical receiver system, and thereby achieve a correct multimode fiber optic coupling of the Gaussian beam received after propagating through atmospheric turbulence. At the same time, a finder scope is attached, which aims to align the multi aperture receiver system with the optical axis of the Gaussian beam propagated through an atmospheric channel. iv This work proposes a set of five experiments which use the normalized variance of the received power as a figure of merit, to compare the fluctuations of power received with both optical collectors in different conditions of atmospheric turbulence. The atmospheric channel used in practice is described in detail, and consists of a 7km optical path in the city of Dayton Ohio, which is subjected to tests in different conditions of atmospheric turbulence, that changes depending on the time of day in which measurements are done. In the case of the Multi Aperture Receiver system, it has been possible to define an effective diameter to compare the increase in sub-apertures with the increase in the total diameter of a monolithic system. With this, it has been possible to introduce a new concept called "sub-apertures averaging", referring to t (open full item for complete abstract)

PHD, Kent State University, 2021, College of Arts and Sciences / Department of Geography

Cold Air Outbreaks (CAOs) are extreme events that can negatively impact the agricultural industry, human health, and cause widespread power outages from increased energy consumption. A systematic CAO classification was developed using two different climate reanalysis data sets from 1979 – 2018. Trends in CAOs were calculated for different regions across the globe and the results from each reanalysis dataset compared with one another to identify discrepancies. CAOs occur more frequently in the Northern Hemisphere than the Southern Hemisphere with the highest number of CAOs in Europe, Central Eurasia, and North America. CAOs were found to have decreased in spatial extent, frequency, duration, and magnitude across much of the globe, particularly across Alaska, Canada, and the North Atlantic, while an increase in CAOs was observed in Eastern Europe, Central Eurasia, and the Southern Ocean. Early and late winter CAOs have also become much less frequent in most regions. Increasing the predictability of CAOs is critical to limiting the adverse impacts on society, but skillful predictions rely on well-defined mechanisms of causation. To improve the understanding of CAO mechanisms, this study examines the relationship between atmospheric and oceanic teleconnection indices and CAOs in the Northern Hemisphere (NH) during two distinct periods, 1979 – 1998 and 1999 - 2018. Changes in the relationship between CAOs and teleconnections during these two periods are calculated and used to determine the teleconnections that currently have the strongest relationship with CAOs across the NH. Several significant relationships are found to no longer be significant while several other significant relationships have emerged, particularly with the Tropical Northern Hemisphere (TNH) pattern. Upstream teleconnections, as opposed to downstream teleconnections, were generally found to have a stronger relationship with CAOs. The East Pacific Oscillation (EPO) and East Pacific/North Pacific (E (open full item for complete abstract)

Master of Science (M.S.), University of Dayton, 2020, Electro-Optics

In this work, simulations of propagation of helical Ince-Gauss beams, elliptical solutions of the paraxial wave equation that carry orbital angular momentum, were performed in order to see how the nature of these modes affects their performance as information carrying beams in free space optical communication systems. Special attention was put in to the effects that the order "p", degree "m" and ellipticity "ε" parameters, and their evolution, have on the robustness of the beam, finding that for a given mode, the chose of basis in which it is projected (ellipticity value) does not heavily affect the light spatial mode performance as information carrier and is instead more heavily affected by the combination of "p", "m" and their difference p−m for the chosen helical Ince-Gauss mode. These results were obtained by varying propagation parameters such as the refractive index structure parameter or propagation distances and using different beam structure parameters as the mentioned "p", "m" and "ε". From the simulations, both intensity and phase transverse profiles were recovered as well as propagation measurements such as the fidelity of the modes, and specially defined scintillation index and strehl ratio. Additionally, the generation of these vortex beams using spatial light modulators was demonstrated, showing the evolution of the modes with the ellipticity "ε" parameter and proposing the detection of these modes using their near-field intensity profile, as it shows more clearly the distribution of the intensity optical vortexes of the modes.

Master of Science (M.S.), University of Dayton, 2020, Aerospace Engineering

Velocity measurement inside of a wind tunnel is an extremely useful quantitative data for a multitude of reasons. One major reason is that velocity has a mathematical relationship with dynamic pressure which in turn influences all the aerodynamic forces on the test model. Many devices and methods exist for measuring velocity inside wind tunnels. At the same time, Doppler wind lidar (light detection and ranging) has been used for decades to make air speed measurements outdoors at long ranges. Lidar has been proven effective for many applications, and it has the potential to solve many of the problems faced by current velocimetry techniques inside wind tunnels. Despite this, minimal research has been performed with Doppler wind lidars inside wind tunnels. While multiple commercial systems exist for making air speed measurements at longer ranges, there are currently no widely available commercial devices designed to work well inside wind tunnels. In this research, initial work is described for the design and development of a continuous wave (CW), coherent wind lidar system. The system is for use as an alternative non-intrusive velocimetry method inside wind tunnels relying on the Doppler effect. A scaled down wind lidar designed to operate at much shorter ranges than current commercial wind lidars can be simpler, less expensive, and require less power. A first iteration of the design was constructed for proof of concept testing with a small-scale wind tunnel at low speeds (7.5-9 m/s). Testing showed that the lidar system could take one-dimensional speed measurements of seeded flow that closely matched Pitot static tube data. When not adding tracer particles to the flow, the lidar return signal was not strong enough for the photodetector used to measure the beat frequency. This research is focused on the process for designing the Doppler wind lidar system, constructing the experimental setup, and studying methods for data analysis. Results of testing presente (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2019, Electrical and Computer Engineering

The interaction between the ocean and lower troposphere in the marine atmospheric boundary layer produces rapid moisture and temperature inversions, which creates atmospheric ducts. Electromagnetic (EM) waves can be entrapped within the duct layers and propagate more efficiently than in normal conditions. The effects of the duct on EM wave propagation result in longer propagation range, signal fades at specific locations, and increased radar clutter. Also, the propagation effects strongly vary with frequency in the nonstandard atmosphere. Hence, good characterizing of the localized refractivity structure is essential to understand the propagation abilities of radio wave communications and radar systems. This dissertation addresses lower atmospheric refractivity inversions from multi-frequency EM measurements, analyzes the accuracy of a numerical weather prediction model over a wide frequency range. The Lower Atmospheric Propagation Ultra-Wide Band (LATPROP-UWB) system is designed and built to measure EM propagation over a long distance for 2 to 40 GHz. The system was deployed during the Coupled Air-Sea Processes and EM Ducting Research (CASPER) East and West Campaigns. In CASPER East, range-dependent propagation loss (PL) up to 55 km was collected. With the upgraded system, fixed link PL was recorded during Casper West. Multi-frequency inversion algorithms are developed to estimate the refractivity profiles. The parabolic wave equation method is used to model EM wave propagation along long-range in low grazing angle. Extensive and concurrent meteorological measurements collected during both CASPER Campaigns are used to evaluate the inversion results. The estimation accuracy improves with a larger number of frequencies in both simulation and measured results. The multi-frequency system also makes the retrieval less dependent on varying environmental conditions when some frequencies are not sensitive to atmospheric conditions. The inversion results show that (open full item for complete abstract)

Master of Science (MS), Ohio University, 2019, Environmental Studies (Voinovich)

Atmospheric mercury is a pollutant of concern due to its detrimental effects on wildlife and humans. It is easily deposited to the environment in its oxidized form known as reactive gaseous mercury (RGM), which enters the atmosphere predominately from coal fired power plants (EPA). A mercury air monitoring site is located in Athens, OH where the ambient RGM data are studied in depth. This research strove to determine 8-year trends of atmospheric RGM and determine source regions affecting RGM levels in Athens. The top 5% RGM concentrations levels for 2009, 2010, 2016, and 2017 were analyzed separately to determine hotspots. The HYSPLIT model was utilized to generate back trajectories of high RGM days. These back trajectories were overlapped into ArcGIS where the most dominant source region was determined to be Northeast of Athens, OH. Meteorological parameters were investigated as well to determine a meteorological scenario attributing to high RGM levels. The RGM levels in Athens from 2009 to 2017 have decreased by 73.14%. However, high RGM days occur in association with stable planetary boundary layer conditions, with an inversion beginning at the surface or when there is an unstable planetary boundary layer with mixing and then an inversion aloft. Meteorology plays a major role in high RGM concentrations in Athens, OH.

Bachelor of Science (BS), Ohio University, 2019, Physics

Atmospheric models have difficulty in accurately predicting concentrations of ozone-related pollutants on the Wisconsin shore of Lake Michigan. This is at least partly due to the difficulty of modeling planetary boundary layer dynamics during lake breezes. This issue motivated the 2017 Lake Michigan Ozone Study: a multi-institutional remote sensing field campaign along the Wisconsin shore of Lake Michigan. Using remote sensing data collected by the University of Wisconsin during this campaign, an analysis has been done on the relative fidelity of two Weather Research and Forecasting nested model runs. The two schemes, referred to as the EPA Baseline and YSU-Noah-Thompson schemes, differ in their parameterization of the planetary boundary layer, surface physics, and microphysics. Focus has been placed on model fidelity capturing the evolution of the thermodynamic and kinematic profiles during high-ozone lake breeze events in Sheboygan, Wisconsin. Both physics schemes show significant failure to forecast daytime surface thermal stability. Increases in spatial resolution show an increase in wind modeling error and a decrease in temperature modeling error.

Bachelor of Arts (BA), Ohio University, 2019, Geography

For decades, there has been a common practice among tornado chasers of targeting the southernmost supercell (colloquially known as the “Tail-end Charlie”) when there are multiple supercells aligned in a north-south manner. This practice is based off of the belief that the southernmost storm has the greatest likelihood of producing a tornado due to its relatively uncontaminated inflow and its tendency to remain isolated longer than cells further north. However, no conclusive evidence exists to confirm this hypothesis. The current study aims to statistically evaluate the distribution of tornado-producing supercells in the United States when multiple (2 or more) supercells are linearly oriented along a north-south axis, to determine if the southern-end storm is indeed favored for tornado production over the others. All cases with lines of multiple north–south-oriented supercells from the full calendar years of 2016 and 2013, as well as specific selected cases from 2011 were gathered using data from the official Storm Prediction Center severe-weather database and Level II WSR-88D data. A total of 568 supercells and 243 tornadoes were sampled associated with 190 north–south-oriented lines. The Chi-squared statistic was used to analyze any possible sources of dependency between the events individually and collectively, the total number of supercells in the line, month of occurrence, geographic region, type of surface boundary initiating the storms, tornado destruction potential index, and azimuthal orientation of the line. Ultimately, there were no statistically significant trends to indicate that southernmost supercells are more prolific tornado producers than other supercells in the line, although some groupings had stronger dependence than others. From this research, the following conclusions were drawn: 1) in the month of April, fewer southernmost supercells produced tornadoes than expected; 2) more north–south-oriented lines occurred in the Southern Plains, but th (open full item for complete abstract)

Master of Science (MS), Ohio University, 2018, Geography (Arts and Sciences)

The state of Oklahoma is located in an area prone to severe hail and tornadoes and central OK represents a bullseye of severe weather. The Wichita Mountain Range, located in southwest OK, spans 97 km in a northwest to southeast direction, while the general wind pattern in southwest OK flows from southwest to northeast, carrying air parcels over the Wichita Mountains. Given the fact that topographic features have been known to affect the initiation of convection, it is possible that the Wichita Mountain Range in southwest OK may influence the initiation of supercell thunderstorms that go on to produce tornadoes and severe hail in central OK. The purpose of this study is to determine whether the Wichita Mountains cause air parcels to ascend through orographic lift, achieving convection initiation. This study will be completed using a combination of historical storm archives, radar-based storm tracking software, archived environmental conditions, statistical and trajectory analyses. Results indicate that there is qualitative and quantitative evidence suggesting that the Wichita Mountain Range does indeed influence the convection initiation of large hail and tornado producing supercells through the forced ascent of air parcels.

Master of Science (MS), Ohio University, 2018, Civil Engineering (Engineering and Technology)

The Yaqui River Basin (YRB) is located in the semi-arid state of Sonora in northwest Mexico. This watershed flow is controlled by three reservoirs: Angostura, Novillo, and Oviachic. In order to assess and improve the management of the Yaqui reservoir system, a daily reservoir operation model was developed. This model is composed of a semi-distributed daily watershed simulation combined with an optimization model. The hydrologic simulation was developed using the Hydrologic Modeling System (HEC-HMS) developed by the US Army Corps of Engineers (USACE) Hydrologic Engineering Center. This simulation framework can estimate the water availability in different regions of the watershed. The HEC-HMS model was integrated to a nonlinear optimization model that estimates the water allocation in order to satisfy the competing water demands from different users according to water rights established in Mexico's National Water Law. The optimization model is developed using the General Algebraic Modeling System (GAMS). The communication between HEC-HMS and GAMS was completely automated via Python scripts for time efficiency reasons. Different hydrological forcing (precipitation, temperature, and solar radiation) scenarios were applied to the HEC-HMS simulation: (1) a network of daily ground observations from Mexican water agencies during the historical period of 1990-2010, (2) gridded fields from the North America Land Data Assimilation System (NLDAS) at 12 km resolution during the same simulation period, and (3) bias corrected NLDAS fields. The NLDAS forcing and bias corrected NLDAS performed better for Angostura and Novillo whereas ground observation datasets provided the best simulation for Oviachic. The simulated reservoir releases were compared to ideal releases at the three reservoirs to generate confidence in the simulation tools. It was concluded that authorized water allocation is unable to satisfy all users' demands. The simulated water allocation satisfied these demand (open full item for complete abstract)

Master of Science (MS), Wright State University, 2017, Physics

Atmospheric turbulence has afflicted accurate observations of celestial bodies since man first gazed upon the stars. In this past century, the technology of adaptive optics was invented to help compensate for the optical distortions that atmospheric turbulence causes. As part of that technology, artificial guide stars, wave front sensors, deformable mirrors, and other optical components were developed to correct these wave aberrations. The purpose of this study focuses on the modeling and configuration of an adaptive optics system that is appropriate for the John Bryan Observatory Quad Axis Telescope System (JBO-Q), which is funded by the United States Air Force. Scaling law modeling of site-specific atmospheric parameters using numerical weather data and laser propagation theory was used determination and optimization of some critical system specifications and threshold parameters for this baseline model.

Master of Arts, The Ohio State University, 2017, Geography

Drought is a prominent climatic hazard in the south-central United States. This study examines spatial variations in the persistence of meteorological drought in Texas, Oklahoma, and Kansas (1900-2015). Drought persistence is analyzed separately for droughts of varying severity, as determined by the U.S. National Drought Monitor (USDM). Results indicate that objective drought thresholds should be utilized to improve drought monitoring. With new thresholds, this research identifies areas where drought persistence is greatest and examines how it varies as a function of drought severity. When drought characteristics were examined at a fine resolution, spatial variability was high. In many cases, intraregional differences in drought behavior were not statistically significant. These findings suggest that drought persistence may be less dependent upon continentality than previously thought. Despite intraregional similarities, there is some evidence that drought persistence is highest across central Texas. Drought persistence forecasts in this region may be ineffective as monthly relationships are not statistically significant. However, there is strong evidence of increasing drought lengths with increasing severities. These results have utility for improving the understanding of drought recovery.

Master of Science (MS), Ohio University, 2017, Geography (Arts and Sciences)

Across Antarctica, most meteorological observations did not begin until the International Geophysical Year of 1957-58, making it difficult to understand Antarctic climate variability during the early 20th century. To overcome this hurdle, this thesis creates, evaluates, and analyzes several seasonal spatial pressure reconstructions that extend back to 1905 across the Antarctic continent. A kriging interpolation method is used to generate the seasonal spatial pressure reconstruction using 19 Antarctic stations as predictors. Multiple evaluation techniques were used to assess the reliability of the spatial pressure reconstructions when compared to ERA-Interim, which is deemed the most reliable gridded pressure dataset after 1979. From all these evaluation metrics, it is concluded that the most reliable spatial pressure reconstructions are for the summer and winter seasons, but all seasons have enough skill to be useful in interpreting pressure variability throughout the 20th century. Using the newly generated spatial reconstructions, it is clearly seen that the negative pressure trend in the late 20th century across the entire continent in DJF is unique when compared to the 100+ year record. Given this uniqueness and contemporary modeling studies, it is likely that stratospheric ozone depletion plays a leading role in the recent negative Antarctic pressure trends in summer. In contrast, the early 20th century in DJF and the entire 20th century for the other seasons are characterized by interannual variability, with strong decadal-scale variability especially prevalent in winter. This highlights the importance of natural variability in causing the majority of ongoing Antarctic circulation pattern changes.

Master of Science, The Ohio State University, 2016, Atmospheric Sciences

Utilization and understanding of risk assessments in disastrous hurricane events aids in the preparation of and recovery from the event; an especially helpful tool to the residents of Gulf of Mexico coastal counties. This hurricane specific analysis consists of variables that make counties along the gulf coast of the United States more vulnerable or resilient to damage from hurricanes and the hypothetical ability to recover in the aftermath. The analysis included social vulnerability based on the demographics of the county, physical data from ten different hurricanes, and the resilience opportunities available to the residents of these counties. Analyses of the specified variables resulted in a correlation between high initial vulnerabilities and high hurricane hazards with respect to higher risks. However, a stronger correlation occurred between the resiliency of the county and the overall risk associated with each hurricane. Counties with larger overall vulnerabilities only received high risks if the county was not equipped with the necessary resiliency factors. Hancock County, while having lower vulnerabilities than other counties and not always acquiring the largest hurricane parameters, was consistently the county with the highest risk in relevant hurricane cases due to its extremely low resiliency. This low resiliency was based on the county's population of over 2 million and its deficiency in emergency services available to the community.