Identifier

etd-03182009-161153

Degree

Doctor of Philosophy (PhD)

Department

Geography and Anthropology

Document Type

Dissertation

Abstract

Tropical cyclones (TCs) are among the most devastating of natural disasters, producing high winds, heavy rainfall, and floods. When TC remnants are considered, these events have impacts nearly nationwide across the U.S. Tropical cyclone activity in the North Atlantic Basin experiences great variability on intra-annual, interannual, and interdecadal timescales. That variability is often associated with El Niño Southern Oscillation (ENSO) and Atlantic Multidecadal Oscillation (AMO). George Cry (1967), in his pioneering study of tropical cyclone-induced rainfall found that TC rainfall presents an intraseasonal pattern over the eastern Unite States, contributing up to 40% of the monthly rainfall. This study replicates much of what was done by Cry (1967) using a denser raingage network and more sophisticated techniques for analysis. Rainfall data for this study comes from 717 stations from the Historical Climate Network covering 31 states to capture the TC contribution in the monthly and seasonal precipitation in the Eastern United States. An approach was used to separate TC rainfall from non-tropical rainfall from 1960-2007. Results showed that September has the highest TC rainfall contribution. Coastal regions of North Carolina, Virginia, and Alabama receive more than 30% of monthly rainfall totals from TCs. Comparisons between 1931-1960 and 1960-2007 shows that the storm track density shifted slightly eastward. TC rainfall, during the period 1960-2007, presented great interannual variability in the frequency, intensity, and duration of the storms (number of storm days). ENSO and AMO phases were found to play different roles in relation to TC rainfall contribution in the U.S. ENSO has a significant signal in relation to the number of storms, but did not have a statistically significant signal in the total of TC rainfall in the eastern U.S. AMO showed a positive correlation with individual stations in the Gulf Coast and in Maine. In addition, ENSO phases are correlated with TC rainfall in Texas.

Date

2009

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Barry Keim

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