Physical Sciences and Mathematics Commons^™

A Climatology Of Snowpack In The Southern Rocky Mountains And Snow To Liquid Ratio Forecasting Techniques Using Model Generated Soundings From The Rapid Refresh Model, Carson Jones

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

Mountainous snowpack represents up to 70% of the total water resources for areas in the western United States. Temperature and precipitation control the accumulation and ablation of the snowpack throughout the cold season, both of which are subject to a changing climate. This study will use a network of snow telemetry (SNOTEL) stations to investigate changes in the snowpack season, snow water equivalent (SWE), and temperature in the southern Rocky Mountain region. Additionally, this study will use model generated soundings from the Rapid Refresh (RAP) model to establish relationships between the depth and cloud proportion of ice crystal growth layers, …

Examining The Effects Of Greenland Ice Sheet Melting And Atlantic Meridional Shutdown On The Climate Of Scandinavia And The British Isles, Tyler Lemburg

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

Earth’s climate has been rapidly changing over the last hundred years, and its global average temperature is rising. However, climate change is far more complicated than a simple increase in temperature. For example, it is theorized that certain regions of Earth, including Scandinavia and the British Isles, could actually become cooler through ongoing climate change processes. Two of these processes are Greenland Ice Sheet (GrIS) melting, and slowdown of the Atlantic Meridional Overturning Circulation (AMOC). This research examines if climate change, through GrIS melting and AMOC slowdown, could contribute to cooler, instead of warmer, temperatures in Scandinavia and the British …

An Observational Study Of Winter Weather-Related Traffic Crashes In Nebraska, Jacob Petr

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

The responsibilities of meteorologists have evolved over time from simply providing a forecast to needing to also understand how those predictions will impact society and then communicating those risks in a clear, concise, and consistent manner. Increased motor vehicle crash numbers due to adverse weather conditions represent one such impact worthy of further study. Snowfall, in particular, significantly increases the overall risk of a crash, which can result in extensive property damage, severe injuries, and even loss of life.This project seeks to supplement traffic crash information in Nebraska by assessing how snowfall impacts crashes across the state. Crash data were …

The Role Of Boundary-Parallel Vertical Wind Shear In Convection Initiation, Alexander J. Krull

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

Convection initiation (CI) remains a forecasting challenge for meteorologists. CI frequently occurs within the vicinity of some airmass boundary or density current. Airmass boundaries are favored areas of convergence, thus associated forced ascent facilitates CI. Features such as misocyclones often develop along the leading edge of airmass boundaries, favoring updraft formation and prompting alterations to the horizontal and vertical flow near the boundary. Airmass boundary characteristics and CI potential have been found to be sensitive to the environmental vertical wind shear. This affects propagation speed, convergence, and thus forced ascent along the leading edge. Previous studies have focused primarily on …

Changes In Mammalian Abundance Through The Eocene-Oligocene Climate Transition In The White River Group Of Nebraska, Usa, Robert Gillham

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

Marine records show major cooling during the Eocene-Oligocene Climate Transition (EOCT). Most proxy studies in the White River Group suggest drying across the EOCT, and some suggest cooling. The lower resolution continental record has hindered a direct correlation of the marine climate record to Nebraska. I explore various correlation schemes and what they imply for faunal changes. This study compiles and analyzes data from 4,875 specimens in the University of Nebraska State Museum (UNSM) collection to test the hypothesis that climate change across the Eocene-Oligocene (E-O) boundary caused significant abundance changes in mammals. A series of binning schemes was created. …

Evaluation Of Viirs Nightfire Product And Comparison With Modis And Viirs Active Fire Products In A Russian Gas Flaring Region., Ambrish Sharma

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

Gas flaring is a commonly used practice for disposing of waste gases emerging from industrial oil drilling and production processes. It is a serious environmental and economic hazard with adverse impacts on air quality, climate, and the public health. Accurate determination of flare locations and estimation of associated emissions are therefore of prime importance. Recently developed Visible Infrared Imaging Radiometer Suite (VIIRS) Nightfire product (VNF) has shown remarkable efficiency in detecting gas flares globally, owing primarily to its use of Shortwave Infrared (SWIR) band in its detection algorithm. This study compares and contrast nocturnal hot source detection by VNF to …

Major And Trace Element Analyses For Studying Oceanic Crustal Construction And Ridge Morphology Along The Kane- Atlantis Supersegment Of The Mid-Atlantic Ridge, Yitong Lyu

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

Faulting style along slow-spreading ridge segments exerts a major control over oceanic crustal construction and ridge morphology. Seafloor spreading along slow-spreading ridges is classified into asymmetrical detachment faulting and symmetrical spreading styles. Magma supply variations may influence the formation of symmetric versus asymmetric segments, but the factors that derive such variations remain unclear. We present U and Th concentration data by isotope dilution for basalts from 24 to 30 ^oN MAR, of which 18 samples were retrieved from detachment faulted and 10 from symmetrical segments. The U-Th concentration results from this study are further compiled with prior published data …

An Analysis Of Differential Reflectivity Arc Characteristics In 109 Supercell Storms, Matthew Wilson

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

Differential reflectivity (Z_DR)arcs are one of the most prominent dual-polarization features of supercell storms, and are manifest as an arc-shaped area of high Z_DR along a supercell’s forward flank reflectivity gradient. Since previous modelling studies have hypothesized that the magnitude of the drop-size sorting by the storm-relative wind which creates the arc signature is related to the strength of the low-level shear and SRH in a storm’s environment, the presence of a strong Z_DR arc is often said to indicate that a storm may have the potential to develop strong low-level rotation and potentially become tornadic. …

A Case Study Analysis Of Two Heavy Snowfall Events And Road Weather Implications In 2018 For Nebraska, Nancy Barnhardt

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

Weather-related car accidents make up approximately a quarter of all crashes even though the amount of time during the year in which they can occur is minimal in comparison to fair weather day crashes. Maintenance Decision Support Systems (MDSS) were developed to help mitigate the number of crashes that occur during winter weather through improved operations along with reducing chemical usage. An MDSS uses weather information to recommend road treatments based on current and future weather conditions. To evaluate the limitations and capabilities of the Nebraska Department of Transportation Maintenance Decision Support System (NDOT-MDSS), case study analysis was performed on …

Insights Into Paleoenvironmental Conditions, Relative Sea-Level, And Carbonate Reservoir Quality Using Ichnology: Middle-Upper Miocene Slope Deposits, Great Bahama Bank, Ryan M. Mustacato

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

Detailed ichnological and petrographic analyses were conducted on two biostratigraphically-constrained intervals (11.9-11.3 Ma and 10.7-9.4 Ma) from the Middle-Upper Miocene stratigraphy of the Great Bahama Bank’s leeward margin to assess spatiotemporal trends in paleoenvironmental conditions and reservoir properties in carbonate slope deposits. Six ichnofacies, varied in expression, are documented: the Skolithos Ichnofacies (distal and impoverished expressions) the Cruziana Ichnofacies (proximal, archetypal, distal and impoverished expressions), the Zoophycos Ichnofacies, the Nereites Ichnofacies, the Glossifungites Ichnofacies, and the Trypanites Ichnofacies. An analysis of spatiotemporal ichnofacies trends reveals two distinct responses of the benthic community to significant environmental perturbations on the slope. An …

Diatom-Inferred Records Of Paleolimnological Variability And Continental Hydrothermal Activity In Yellowstone National Park, Usa, Sabrina Brown

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

Fossil diatoms were used to reconstruct paleoclimatic and hydrothermal conditions in Yellowstone National Park. First, an extensive literature review summarizes the current state of knowledge about eukaryotic organisms characteristic of continental hydrothermal environments. Eukaryotes in hydrothermal systems can live at extremes of acidity (pH 9.0), and at moderately high temperatures (<62 >^○C). Silicate and carbonate precipitation in continental hydrothermal environments is mediated by eukaryotic organisms, which are important members of biofilm communities.

A case study of alkaline-chloride sinter deposits in Yellowstone Lake and the Upper Geyser Basin inferred in-situ diatom growth rather than post-depositional accumulation of valves settling from …