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Full-Text Articles in Physical Sciences and Mathematics
Radar Signatures In Tropical Cyclone Tornadic And Nontornadic Supercells, Michaela Wood
Radar Signatures In Tropical Cyclone Tornadic And Nontornadic Supercells, Michaela Wood
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
Tropical cyclones (TCs) contain highly-sheared environments that are conducive for supercell thunderstorms. These TC supercells sometimes produce tornadoes, often with little warning. Given the often-close proximity of tornadic and nontornadic TC supercells, environments may not be well-distinguished, pointing to the potential value of radar observations. In this study, dual-polarimetric radar signatures of a sample of TC supercells are examined in the context of known supercell structure and microphysics. Tornadic and nontornadic TC supercells are compared with their midlatitude counterparts, and the environments and characteristic structure of these storms are shown to be notably different. An attempt is made to distinguish …
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 …
The Role Of Boundary-Parallel Vertical Wind Shear In Convection Initiation, Alexander J. Krull
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 …
Modeling And Satellite Remote Sensing Of The Meteorological Impacts Of Irrigation During The 2012 Central Plains Drought, Clint Aegerter
Modeling And Satellite Remote Sensing Of The Meteorological Impacts Of Irrigation During The 2012 Central Plains Drought, Clint Aegerter
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
As irrigation is increasingly needed for agricultural production, it is becoming progressively more important to understand not only how irrigation impacts water availability, but how the introduction of this water into the soil impacts weather and climate through land-atmosphere interactions. In the summer of 2012, the Central Plains of the United States experienced one of its most severe droughts on record. This study examines the meteorological impacts of irrigation during this drought through observations and model simulations using the Community Land Model (CLM) coupled to the Weather Research and Forecasting (WRF) model. A simple parameterization of irrigation processes is added …
An Examination Of The Mechanisms And Environments Supportive Of Bow Echo Mesovortex Genesis, George Limpert
An Examination Of The Mechanisms And Environments Supportive Of Bow Echo Mesovortex Genesis, George Limpert
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
Low-level mesovortices are associated with enhanced surface wind gusts and high-end wind damage in quasi-linear thunderstorms. Although damage associated with mesovortices can approach that of moderately strong tornadoes, skill in forecasting mesovortices is low. The overarching goal of this work is to understand mesovortices and how they develop, to improve the skill in forecasting them. This was done by developing a climatology of mesovortices, which required a tracking algorithm, and numerical simulations were conducted to answer questions that could not be answered through the observational data. A climatology of mesovortices was constructed from 44 events during 2009 and 2010 to …
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 …
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 …
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 …