Degree

Doctor of Philosophy (PhD)

Department

Geography and Anthropology

Document Type

Dissertation

Abstract

Precipitation changes are one of the most important potential outcomes of a warming climate because of how essential it is to society and ecosystems. Sub-daily precipitation time series provide more information on precipitation characteristics, particularly frequency, intensity, and duration compared to daily data. In a series of four peer-reviewed manuscripts, this research investigates sub-daily precipitation characteristics from a climatological perspective. The first study introduces a climatology of hourly precipitation for four first-order weather stations across Louisiana, explores possible changes in the hourly precipitation distribution, and links winter Gulf of Mexico sea surface temperatures to the frequency of hours with precipitation. The second manuscript introduces a climatology of hourly precipitation characteristics, investigates trends in precipitation hours, accumulation, and uses four different times series to determine if precipitation intensity is changing across the Southeast U.S (SeUS) from 1960–2017. The third study uses regression to determine the effect of the El Niño-Southern Oscillation on winter precipitation characteristics at 54 first-order weather stations across the SeUS from 1950–2017. The final study tests for trends in annual maximum accumulation series, station specific annual 90th percentile hourly accumulations, average and maximum dry spell durations, and maximum annual wet period. Results from these studies show the hourly precipitation distribution has changed across the region. While the frequency of annual precipitation hours remains largely the same at most stations in the SeUS, average accumulations and intensity of hourly events have increased while the average duration of events decreased. The magnitude of the heaviest hourly events showed little change at most stations and the frequency of 90th percentile events did not increase broadly across the region, revealing changes in the distribution are largely caused by more hours with above average accumulations

Committee Chair

Keim, Barry

DOI

10.31390/gradschool_dissertations.4983

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