Date of Award
December 2024
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Atmospheric Sciences
First Advisor
Jake Mulholland
Abstract
Urban areas absorb and radiate energy at a higher rate compared to surrounding rural areas due to several factors, including an urban area’s tendency to have sparse vegetation and tree canopies along with high incidences of pavement. Urban areas have been shown to impact both the environment in which thunderstorms form (by altering thermodynamic, microphysical, and wind flow patterns) and the thunderstorms themselves; however, most of this previous work focused on isolated thunderstorms amid weak environmental vertical wind shear. This thesis analyzes how the structure of observed quasi-linear convective systems (QLCSs)—i.e., lines of thunderstorms—are altered as they pass over urban areas. Due to every urban area’s unique size, along with distribution of various land cover types and population, their potential effectiveness at modifying QLCSs will vary. A QLCS storm track database between 2010–2021 was leveraged using archived radar data from the GridRad (3-D Gridded NEXRAD WSR-88D Radar Data)-Severe database. These archived radar data were used to note any variations in observed QLCS size, structure, and intensity before, during, and after passing over six different urban areas of various sizes (and one “control” rural area) across the United States that frequently experience QLCSs.The results of the observed radar analysis show a tendency for QLCS tracks to display higher (lower) column maximum reflectivity, vertically integrated liquid density, and echo top heights upwind (over and downwind) of the centroid of each urban area. Even though statistically significant variations in the three radar variables examined were present across many of the urban areas, it is difficult to confidently draw any overarching conclusions with respect to the exact mechanisms that may be causing these variations. Overall, support of downwind intensification of QLCSs after passing over urban areas (as noted in recent idealized numerical simulations and with other convective) was more evident in the literature than in the observed radar analysis. Possible reasons for these trends are discussed and avenues for future work are highlighted.
Recommended Citation
Wooton, Claiborne, "Investigating The Impact Of Urban Areas On Quasi-Linear Convective Systems" (2024). Theses and Dissertations. 6582.
https://commons.und.edu/theses/6582