Type of Document Master's Thesis Author Russo, Michelle Marie URN etd-07022004-111634 Title Extreme Precipipitation Events in East Baton Rouge Parish: An Areal Rainfall Frequency/Magnitude Analysis Degree Master of Science (M.S.) Department Geography & Anthropology Advisory Committee
Advisor Name Title Barry Keim Committee Chair Andrew Curtis Committee Member John Sansalone Committee Member Keywords
- rainfall frequency magnitude analysis
- East Baton Rouge Parish
- synoptic type analysis
- areal rainfall summation methods
- interpolation techniques
- extreme precipitation
- areal rainfall analysis
Date of Defense 2004-06-18 Availability unrestricted AbstractSevere rainfall events are one of the most frequent weather hazards in the United States. These events are particularly problematic for the southeastern United States because of its subtropical climate. For these reasons, and because of the recent urban growth in the parish, East Baton Rouge Parish officials are concerned whether the current stormwater drainage system can keep pace with development. As a result, this project evaluated the rainfall frequency/magnitude for parish-wide extreme events and their synoptic forcing mechanisms. To this end, this research mapped parish-wide storms and compared three interpolation techniques. It also compared two methods of areal summation and five quantile estimation techniques.
Results of cross-validation suggested kriging was the best interpolation technique for this research. Also, statistical testing showed that there were no significant differences between parish-wide rainfall totals calculated using gridded areal summation and contoured areal summation methods. Although the non-parametric SRCC method best fit the storm partial duration series, the parametric Beta-P was selected to produce quantile estimates.
When areal design storms for East Baton Rouge Parish were compared to point rainfall totals for the parish from previous studies, areal totals were generally smaller. However, totals were larger for longer duration events (12- and 24-hour) at longer return intervals (50- and 100-year). This was attributed to differences in distributions used in quantile estimation and periods of record between the studies. This research included some large events (i.e., T.S. Allison II) that were not included in the two earlier studies.
Results from the synoptic analysis showed that the frontal forcing mechanism dominated storms at all durations. Also, results showed that only the 3-hour duration included air-mass induced events, suggesting that these events were not generally a problem for larger areas, and were not significant in an areal analysis.
Interannual variability showed that the years with the most events were associated with El Niņo events, which increases precipitation in Louisiana, especially during winter. Also, most extreme events tend to occur in the month of April and are produced by fronts. In contrast, most extreme events resulting from tropical activity occurred in September.
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