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dc.contributor.advisorAshley, Walker S.en_US
dc.contributor.authorStrohm, Jacoben_US
dc.date.accessioned2019-12-03T21:27:48Z
dc.date.available2019-12-03T21:27:48Z
dc.date.issued2019
dc.identifier.urihttps://commons.lib.niu.edu/handle/10843/21655
dc.descriptionCommittee members: Changnon, David; Handlos, Zachary.en_US
dc.descriptionAdvisor: Ashley, Walker S.en_US
dc.descriptionIncludes illustrations and maps.en_US
dc.descriptionIncludes bibliographical references.en_US
dc.description.abstractQuasi-linear convective systems, or QLCSs, are a common, organized thunderstorm mode in the U.S. Over the last fifty years, severe weather research has focused on the supercell, but, recently, QLCSs have become an increasingly important area of study. Researchers and operational meteorologists realize that this morphology is difficult to forecast and may be responsible for a large proportion of the severe weather reports in the eastern two-thirds of the U.S. This study seeks to determine the degree to which QLCSs threaten humans and their assets by, first, assessing their climatology and, second, measuring their contribution to the severe report record. Initially, an objective classification scheme was developed and employed to detect and track QLCSs on conterminous U.S. composite radar data spanning the most recent two decades. The objective classification scheme, or computer algorithm, was constructed using machine learning techniques on thousands of subjectively, expert-defined QLCSs from a sample of observed mesoscale convective system events during the observed record. After the scheme was tested and verified, a descriptive climatology of QLCSs was produced. The climatology assessed algorithm-identified QLCS slices (instantaneous footprint of an event) and swaths (the entire footprint of an event) as units of measure, providing the first, long-term spatiotemporal analysis of this morphology. Thereafter, QLCS slices were linked with the severe storm database to determine the proportion of thunderstorm hazard reports produced by this morphology. Results show that, on average, there are 139 QLCSs in any given year. The majority occur in three corridors, depending on the year and season: the eastern High Plains into western Missouri and Arkansas; the Midwest, stretching from Iowa through Wisconsin and northern Illinois to Indiana; and the South, from the central Gulf Coast to Tennessee. QLCSs are found to account for more than one-third of severe wind reports, as well as more than one-fifth of reported tornadoes. The overarching goal of the research was to 1) develop an objective analysis routine that can assist meteorologists in identifying QLCSs in observed and simulated radar reflectivity data, 2) provide the first objectively identified, long-term climatology of QLCSs in the U.S., and 3) increase scientific understanding of the impacts of QLCS hazards on the populace and built environment.en_US
dc.format.extent71 pagesen_US
dc.language.isoengen_US
dc.publisherNorthern Illinois Universityen_US
dc.rightsNIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.en_US
dc.subject.lcshGeographyen_US
dc.subject.lcshMeteorologyen_US
dc.titleA climatology of quasi-linear convective systems in the U.S.en_US
dc.type.genreDissertation/Thesisen_US
dc.typeTexten_US
dc.contributor.departmentDepartment of Geographic and Atmospheric Sciencesen_US
dc.description.degreeM.S. (Master of Science)en_US


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