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University of Nebraska - Lincoln
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
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- Meteorology (4)
- Climate (2)
- Lightning (2)
- MODIS (2)
- Satellite (2)
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- Snow (2)
- Supercells (2)
- Verification (2)
- Weather (2)
- Wildfire (2)
- Algorithm (1)
- Alternative energy (1)
- Arctic (1)
- Atmospheric Attenuation (1)
- Boreal forest (1)
- Cobb (1)
- Crashes (1)
- Cryosphere (1)
- Doppler radar (1)
- Dual polarimetric analysis (1)
- Energy (1)
- Energy balance (1)
- Evapotranspiration (1)
- Fire Radiative Power (1)
- Fire Weather (1)
- Fire weather (1)
- Flash Multiplicity (1)
- Forecast (1)
- Forecasting (1)
- Greenhouse (1)
Articles 1 - 14 of 14
Full-Text Articles in Meteorology
Polarimetric Radar Signatures In Significant Severe Left-Moving Supercells, Raychel Nelson
Polarimetric Radar Signatures In Significant Severe Left-Moving Supercells, Raychel Nelson
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
Left-moving (LM) supercells, though rarer than right-moving (RM) supercells, may produce significant severe weather. However, there are very few existing studies on LM supercells, particularly polarimetric radar analyses. The upgrade of the nationwide Weather Surveillance Radar-1988 Doppler (WSR-88D) network to polarimetric capability and subsequent studies vastly improved understanding of RM supercells, but similar efforts have largely not been made for LM supercells. This study employs an automated polarimetric radar signature detection algorithm to examine a dataset of significant severe (hail ≥ 2.00”, wind ≥ 65 kts) LM supercells to quantify their polarimetric signatures. Comparisons are made with RM supercells to …
A Dual-Polarimetric Analysis Of A Large Sample Of Left-Moving Supercells, Ben Schweigert
A Dual-Polarimetric Analysis Of A Large Sample Of Left-Moving Supercells, Ben Schweigert
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
Supercells have been researched extensively since they were first described over 50 years ago. They are prolific severe weather producers, responsible for the most severe hail, severe wind gusts, and tornadoes. These rotating thunderstorms require attention from forecasters to protect life and property from their threats, most effectively done with Doppler radars. While extensive amounts of radar-based investigations have been completed, they focused almost exclusively on right-moving (RM) supercells, resulting in a knowledge gap surrounding their counter-rotating (left-moving, LM) partners. This study works to fill the void by developing a dataset of LM supercells and analyzing the dual-polarimetric features observed …
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 …
Case Studies Of Alberta Clipper Systems And The Impacts On Winter Weather Road Maintenance, Cameron Wunderlin
Case Studies Of Alberta Clipper Systems And The Impacts On Winter Weather Road Maintenance, Cameron Wunderlin
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
Winter weather can cause profound impacts to a variety of economic sectors in the mid-latitudes. In the Great Plains of North America, one sector that is highly impacted by winter weather is road transportation. The burdens to road transportation caused by winter weather have led to the adoption of a Maintenance Decision Support System (MDSS) by the Nebraska Department of Transportation (NDOT). Using both observational and numerical weather model data, NDOT-MDSS generates both winter weather forecasts and winter road maintenance recommendations. Little is known about how well NDOT-MDSS is forecasting conditions for different winter weather events. Using a case study …
An Observational Study Of Winter Weather-Related Traffic Crashes In Nebraska, Jacob Petr
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 …
Retrieval Of Sub-Pixel-Based Fire Intensity And Its Application For Characterizing Smoke Injection Heights And Fire Weather In North America, David Peterson
Retrieval Of Sub-Pixel-Based Fire Intensity And Its Application For Characterizing Smoke Injection Heights And Fire Weather In North America, David Peterson
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
For over two decades, satellite sensors have provided the locations of global fire activity with ever-increasing accuracy. However, the ability to measure fire intensity, know as fire radiative power (FRP), and its potential relationships to meteorology and smoke plume injection heights, are currently limited by the pixel resolution. This dissertation describes the development of a new, sub-pixel-based FRP calculation (FRPf) for fire pixels detected by the MODerate Resolution Imaging Spectroradiometer (MODIS) fire detection algorithm (Collection 5), which is subsequently applied to several large wildfire events in North America. The methodology inherits an earlier bi-spectral algorithm for retrieving sub-pixel …
Periodicities Of Peak Current And Flash Multiplicity In Cloud To Ground Lightning, Alexander R. Gibbs
Periodicities Of Peak Current And Flash Multiplicity In Cloud To Ground Lightning, Alexander R. Gibbs
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
Research on lightning has been conducted on various topics including thunderstorm electrification and climatology of lightning strikes however; there are still some characteristics of lightning that are not well known, such as flash multiplicity and peak current as a function of individual thunderstorms. These characteristics are the leading cause of injuries and damage each year. This study examines a severe weather event in Minnesota on 16 September 2006, in order to determine what may cause peak current and flash multiplicity. Cycles in peak current and flash multiplicity are identified and then associated with CAPE to determine if a thunderstorm’s updraft …
Water And Energy Balance Response Of A Riparian Wetland To The Removal Of Phragmites Australis, Phillip Mykleby
Water And Energy Balance Response Of A Riparian Wetland To The Removal Of Phragmites Australis, Phillip Mykleby
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
Vegetation and climate both play integral roles in water availability, particularly for arid to semi-arid regions. Changes in these variables can lead to extreme shortages in water for regions that rely on water for crop irrigation (i.e., the Great Plains). The objective of this study is to evaluate the impacts of vegetation on water availability in the Republican River basin in central Nebraska. Decreases in streamflow have been observed in the river basin for many years and, as a result, an invasive riparian plant species (Phragmites australis) is being removed in an effort to reduce evapotranspiration and reclaim …
Verification Of The Cobb Snowfall Forecasting Algorithm, Josh Barnwell
Verification Of The Cobb Snowfall Forecasting Algorithm, Josh Barnwell
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
Forecasting storm total snow accumulation is one of the most difficult aspects of meteorological forecasting. The forecaster has to interpret three main variables in order to forecast snowfall accurately. These forecasting variables are the duration of the snowfall, the amount of liquid water the storm will produce, and the snow density or snow ratio. With the advancement of computer models in recent history, the need for a quick and easy interpretation of these variables has grown, and to improve on previous forecasting techniques’ disadvantages with including the three snow forecasting variables. The Cobb Method snowfall forecasting algorithm utilizes model data …
Trends Of Wind And Wind Power Over The Coterminous United States, Eric M. Holt
Trends Of Wind And Wind Power Over The Coterminous United States, Eric M. Holt
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
The trends of wind and wind power at a typical wind turbine hub height (80 m) are analyzed using the North American Regional Reanalysis (NARR) dataset for 1979-2009. Based upon the wind speeds at NARR’s vertical layers right above and below the 80 m level, the wind speeds at 80 m are estimated using two methods assuming the wind profile respectively as linear and power-law distribution with respect to the altitude in the lower boundary layer. Furthermore, we calculate the following variables at 80 m that are needed for the estimation and interpretation of wind power: the air density, zonal …
Improved Verification And Analysis Of National Weather Service Point Forecast Matrices, Paul Fajman
Improved Verification And Analysis Of National Weather Service Point Forecast Matrices, Paul Fajman
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
Verification is the process of determining the quality of forecast information. Office and personal forecast verifications are significantly lacking throughout the National Weather Service for many reasons. The primary reasons are that verification is time consuming, tedious, and monotonous. This research attempted to ease that process by creating new computer procedures to automate the verification process. The new procedures were tested using two years of forecasting data from November 2007 to November 2009 from the Omaha/Valley Weather Forecasting Office to serve as a framework for future verifications. Point Forecast Matrices (PFM) produced by the National Weather Service twice daily and …
An Intercomparison Of Regional Atmospheric Circulation And The Melt Season Loss Of Arctic Snow Cover And Sea Ice Extent Across The Land-Ocean Boundary, Angela C. Bliss
An Intercomparison Of Regional Atmospheric Circulation And The Melt Season Loss Of Arctic Snow Cover And Sea Ice Extent Across The Land-Ocean Boundary, Angela C. Bliss
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
This study is designed to compare the monthly continental snow cover and sea ice extent loss in the Arctic with regional atmospheric conditions including: mean sea level pressure, 925 hPa air temperature, and mean wind direction among others during the melt season (March-August) over the 29-year study period 1979-2007. Little research has gone into studying the concurrent variations in the annual loss of continental snow cover and sea ice extent across the land-ocean boundary, since these data are largely stored in incompatible formats. However, the analysis of these data, averaged spatially over three autonomous study regions located in Siberia, North …
Impacts Of Meteorological Factors On Modis-Observed Fire Activity In The North American Boreal Forest: The Role Of Lightning, David A. Peterson
Impacts Of Meteorological Factors On Modis-Observed Fire Activity In The North American Boreal Forest: The Role Of Lightning, David A. Peterson
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
The meteorological impact on wildfire activity in the North American boreal forest during the fire seasons of 2000 – 2006 is statistically analyzed through an integration of the following data sets: the MODerate Resolution Imaging Spectroradiometer (MODIS) level 2 fire products, the 3-hourly 32-km gridded meteorological data from North American Regional Reanalysis (NARR), the instantaneous lightning data collected by the Canadian Lightning Detection Network (CLDN), and the Alaska Lightning Detection Network (ALDN). Positive anomalies of the 500 hpa geopotential height field, convective available potential energy (CAPE), number of cloud-to-ground lightning strikes, and the number of consecutive dry days are found …