Collaborative Research: Exploring Lata Holocene Sedimentary Archives of Extreme Storms in the Northeastern United States

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The potential for rapid changes in the global climate system raises concerns about potential risks to coastal communities and ecosystems from tropical cyclones. Understanding how past changes in tropical cyclone activity may be linked to changes in climate will aid the projection of future changes and possibly mitigate socio-economic impacts. By recording how past changes in intense hurricane activity has varied during the past 2000 years, this project will reconstruct landfalls from intense hurricanes from sediment records along the coast from New Jersey to Massachusetts and will extend the temporally limited instrumental record in the western North Atlantic Ocean.Intellectual MeritIntense hurricanes pose a significant threat to lives and resources in heavily populated regions and can extensively modify coastal landforms. Given the relative rarity of intense hurricanes making landfall (e.g. 1 per 100 yr in New England) and the shortness of the instrumental record, little is known about past patterns of intense hurricane activity. The development of long-term records (1000 years or longer) of hurricane activity would make it possible to examine how past climate change may have influenced the frequency, intensity, and region of occurrence of hurricanes. Storm surge and waves create overwash deposits that are preserved within coastal sedimentary environments and that can provide a record of severe storms. Previous work has shown that intense hurricane strikes produce a distinctive sedimentary signature that can be used to reconstruct long-term records of these events. Extensive backbarrier salt marshes and coastal freshwater ponds in the northeastern United States are well situated to receive sediments during intense hurricane landfalls. These normally low-energy environments are dominated by fine-grained highly organic sediments, with the exception of episodic deposition of coarser-grained mineral sediments from the beach and near-shore environment during extreme storms. Sediment obtained from a series of cores from each site can be used to map and date storm-induced deposits. This project will develop sedimentary records of intense hurricanes for the last 2000 years within three study areas: 1) New York/New Jersey Bight, 2) eastern CT/western RI, and 3) Buzzards Bay, MA. Storm-induced deposits will be identified, mapped and dated with a variety of isotopic and stratigraphic methods. Multiple sites with different flooding thresholds within each study area will allow estimation of the elevation and distribution of individual prehistoric storm surge events and to determine which storm-induced deposits likely resulted from intense hurricane strikes. With the resulting records of intense hurricane activity, the group will explore links between the frequency of these events and known climate oscillations such as the Little Ice Age and Medieval Warm Period as well as indices of climate variability such as ENSO and the North Atlantic Oscillation.Broader ImpactsThe results of this study will be particularly useful to coastal resource managers, disaster mitigation managers, and policy makers and will enable these groups to make informed decisions regarding appropriate management practices and regulatory strategies. Other stakeholders (coastal zone managers; habitat restoration groups; land managers; business interests concerned with managing risk; coastal property owners and coastal scientists) will benefit from the results of this project. The research should help planning to reduce the loss of human lives and valuable coastal resources.