Publication Date:
2022-05-25
Description:
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2009.
Description:
Tropical cyclone activity over the last 5000 years is investigated using overwash
sediments from coastal lagoons on the islands of Vieques, Puerto Rico and Koshikijima,
Japan. A simple sediment transport model can reproduce the landward fining deposits
observed at Vieques, and reveals that although the record exhibits centennial-tomillennial
changes in hurricane overwash frequency, the magnitude of these flooding
events has remained relatively constant. Stochastic simulations of hurricane overwash
show that breaks in activity at Vieques are extremely long and unlikely to occur under the
current hurricane climatology and the present barrier morphology. Periods of less
frequent hurricane deposition at Vieques are contemporaneous with intervals of increased
El Niño occurrences and reduced precipitation in West Africa, suggesting a dominant
influence by these two climatic phenomena. Hiatuses in overwash activity between 3600-
to-2500 and 1000-500 years ago are longer than what is generated by overwash
simulations under a constant El Niño-like state, indicating that mechanisms in addition to
variability in the El Niño/Southern Oscillation are required to completely produce the
overwash variability at Vieques. Periods of low overwash activity at Vieques are
concurrent with increased overwash activity at Kamikoshiki and may indicate a
correspondence between tropical cyclone activity in the western Northern Atlantic and
the western North Pacific.
Description:
Funding for this research was provided by the Earth Systems History Program of
the National Science Foundation, the Risk Prediction Initiative, the National Geographic
Society, the Andrew W. Mellon Foundation Endowed Fund for Innovative Research, and
graduate student fellowships from the Coastal Ocean Institute at Woods Hole
Oceanographic Institution and the United States Geological Survey.
Keywords:
Cyclones
;
Sedimentation and deposition
Repository Name:
Woods Hole Open Access Server
Type:
Thesis
Format:
application/pdf
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