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University of Nebraska - Lincoln
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
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- Supercells (2)
- Analysis (1)
- Biostratigraphy (1)
- Cretaceous (1)
- Dual-Polarization Radar (1)
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- Earthquake Relocation (1)
- Earthquakes (1)
- Geology (1)
- Geophysics (1)
- Gravity Base Station (1)
- Hydrologic (1)
- Hydrology (1)
- MAHTE (1)
- Micropaleontology (1)
- Nebraska (1)
- Nebraska wetlands (1)
- Polar research (1)
- Polarimetric (1)
- Polarimetric Radar (1)
- Preexisting airmass boundaries (1)
- Proximate Supercells (1)
- Rainwater basin (1)
- Rainwater basin wetlands (1)
- Statistical (1)
- Supercell (1)
- Supercell Environments (1)
- TORUS (1)
- Wetland (1)
- Wetlands (1)
Articles 1 - 8 of 8
Full-Text Articles in Physical Sciences and Mathematics
Human And Hydrologic Influences On Nebraska's Endangered Rainwater Basin Wetlands, Sarah Thompson
Human And Hydrologic Influences On Nebraska's Endangered Rainwater Basin Wetlands, Sarah Thompson
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
Over half of wetlands in North America have been lost or degraded. Rainwater Basin (RWB) wetlands, located in south-central Nebraska, are a primary example of such loss; an estimated 90% have been destroyed by land conversion for agriculture. Remaining RWB wetlands are often embedded in row-crop fields, where they are threatened by altered surface water runoff flow, drainage features, and excess sediment inputs. Efforts at the state and federal level have been made to preserve this wetland complex due to the critical stopover habitat these wetlands provide for migratory birds. Land managers work to maintain sufficient water levels during migratory …
Impacts Of Physical Parameterization Schemes And Soil Moisture Initialization On Boundary Layer Evolution In The Weather Research And Forecasting (Wrf) Model, Grace Cutting
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
Numerical weather prediction (NWP) models have become a necessary addition to the atmospheric research community over the last several decades, and atmospheric modeling has been used internationally for numerous operational and research purposes. NWP models contain a vast number of combinations of physical and dynamical parameterization schemes; however, they are not always accurate in forecasting weather phenomena at a particular location, as different combinations of parameterization schemes represent differing conditions. Weather Research and Forecasting (WRF) model simulations were run to explore which of the commonly used planetary boundary layer (PBL) schemes best represented upper-air data (as well as PBL evolution) …
Using Remote And In Situ Observations From Torus To Investigate A Preexisting Airmass Boundary And Its Influence On A Tornadic Supercell On 28 May 2019, Kristen Axon
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
During the 2019 field phase of Targeted Observation by Radars and UAS of Supercells (TORUS), a preexisting airmass boundary was sampled on 28 May 2019 in north-central Kansas in close proximity to a tornadic supercell. This work hypothesized that the preexisting airmass boundary was associated with a mesoscale air mass with high theta-E (MAHTE) that favorably interacted with the tornadic supercell to increase the likelihood of tornadogenesis. Observations from TORUS including mobile mesonets, unoccupied aerial vehicles, soundings, and ground-based mobile radar were used along with GOES-16 visible satellite imagery, Kansas mesonet surface stations, and KUEX WSR-88D data to investigate this …
The Diatom Dark Ages: Identification Of Mid-Cretaceous Arctic Platform Diatoms From The Basal Transgression Of The Kanguk Formation, Devon Island, Nunavut, Canada, Megan Heins
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
The lower part of the mid-Cretaceous Kanguk Formation (Lower Turonian interval) contains an important paleontological record crucial to the characterization of a poorly known interval of fossil marine diatoms history. Kanguk Formation mudstones are exposed in a ~200 m-thick section on Devon Island, Nunavut, Canadian High Arctic. Diatoms at this location are well-preserved due to shallow burial on this Arctic Platform site. The rock sequence was protected from glacial erosion that removed much of the Cretaceous record by being down-faulted in a linear graben. Study of these well-preserved fossil diatoms allows for a documentation of the assemblage, identification of potentially …
Comparing Polarimetric Signatures Of Proximate Tornadic And Non-Tornadic Supercells In Similar Environments, Devon Healey
Comparing Polarimetric Signatures Of Proximate Tornadic And Non-Tornadic Supercells In Similar Environments, Devon Healey
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
While much research has shown that characteristics of the environment surrounding supercells can potentially indicate their likelihood to become tornadic, it is not uncommon for tornadic and non-tornadic supercells to coexist in seemingly similar environments. In these situations, it is difficult operationally to separate tornadic from non-tornadic supercells using environmental observations alone. Given that tornadic and non-tornadic supercells have been found to coexist in similar environments, something must be occurring beneath the observational and/or model gridscale that is supporting tornadogenesis in some supercells while inhibiting it in others. This study examines dual-polarimetric radar signatures of proximate tornadic and non-tornadic supercells …
Using Field Scale Electrical Data To Understand Real-Time Agricultural Water Delivery, Bradley Dowell
Using Field Scale Electrical Data To Understand Real-Time Agricultural Water Delivery, Bradley Dowell
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
Areas across the High Plains (Ogallala) Aquifer region are experiencing unsustainable groundwater level declines and impacts to streamflow due to increasing human influence, posing challenges for sustaining future agricultural economies and groundwater resources. State and local agencies manage water using groundwater models, which are not at the same temporal and spatial scale as water management on farms. Well-informed agricultural water usage cannot be achieved without reliable and cost-effective water use at farm scale. Water meters are expensive and rarely installed unless required by the state or other regulatory agency; however, most center pivots have their own power supply, which reports …
Toward The Understanding Of The 2018 Arnold, Ne Earthquake Cluster: Relocation Of Hypocenters And Establishment Of New Gravity Base Stations, Kris Guthrie
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
In 2018, 27 unexpected earthquakes occurred in central Nebraska near Arnold. These earthquakes have no readily apparent cause and no evidence of the responsible fault system is seen at the surface. A joint analysis of vintage, regional gravity and magnetic datasets before the first earthquake revealed a lineament that could represent a pre-existing fault system. New high resolution potential fields data are needed to confidently map the subsurface features around the cluster. To design a survey and collect the data, the following tasks need to be addressed: [1] The earthquakes’ hypocenters need to be improved (relocated) to increase the efficiency …
An Analysis Of Associations Between Polarimetric Supercell Signatures, Erik Green
An Analysis Of Associations Between Polarimetric Supercell Signatures, Erik Green
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
Supercell thunderstorms produce unique polarimetric radar signatures that are not often observed in unorganized deep convection. Repetitive signatures include deep and persistent differential reflectivity (ZDR) columns and the ZDR arc signature, which are both indicative of thermodynamic and microphysical processes intrinsic to supercells. Prior investigations of supercell polarimetric signatures, both those observed by operational and research radars, and those simulated numerically, reveal positive correlations between the ZDR column depth and cross-sectional area and quantitative characteristics of the radar reflectivity field. This study expands upon prior work by incorporating a dataset of discrete, right moving supercells …