Late Holocene hurricane activity and climate variability in the northeastern Gulf of Mexico

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 September 2011Hurricane activity in the Northeastern Gulf of Mexico and its relationship to regional and large-scale climate variability during the Late Holocene is explored. A 4500-year record of hurricane-induced storm surges is developed from sediment cores collected from a coastal sinkhole near Apalachee Bay, Florida. Reconstructed hurricane frequency is shown to exhibit statistically significant variability with the greatest activity occurring between 2700 and 2400 years ago and the least activity between 1900 to 1600 years ago and after 600 years ago. Proxy records of stormrelevant climate variables contain similar timescales of variability and suggest both regional and large-scale mechanisms have influenced hurricane activity on centennial to millennial timescales. In particular, low-frequency migrations of the Loop Current may exercise control over regional hurricane activity by changing the thermal structure of the upper ocean and influencing the role of storm-induced upwelling on hurricane intensification. A new method for estimating the frequency of hurricanegenerated storm surges is presented and applied to Apalachee Bay, Florida. Multisite paleohurricane reconstructions from this region are developed, and the effects of geographic boundary conditions and temporal resolution on estimates of paleohurricane frequency are explored.Financial support provided by the American Meteorological Society, the National Science Foundation, the Bermuda Risk Prediction Initiative, the National Center for Airborne Laser Mapping, and the Coastal Ocean Institute