Doctoral Dissertation Research: Proxy Records of Paleohurricane Activities for the Western and Southern Caribbean

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This project aims to establish the geological proxy records of hurricane activities in the western and southern parts of the Caribbean region. Shifts in the location of hurricane tracks occur across a variety of scales, from interannual to millennial. The damage hurricanes inflicted upon the United States during the 2004 and 2005 seasons dramatically demonstrates the societal importance of such shifts. The goal of this doctoral dissertation research project is to identify the climatic forcing mechanisms responsible for these shifts by correlating long-term climate and hurricane histories. Such a correlation has not heretofore been possible due to gaps in the paleohurricane record, particularly from the oft-struck Caribbean region. This study attempts to close this gap by obtaining proxy hurricane records from sediment cores from coastal sites in Belize, Nicaragua and Barbados. Major hurricanes (category 3 or greater) typically leave an identifiable sedimentary signature in coastal lakes and swamps by transporting recognizable beach and marine material, such as sand and marine organisms, inland where it is deposited onto more organic material. A comprehensive history of hurricane landfalls extending thousands of years into the past can be determined by counting and dating these hurricane-generated layers. Present evidence indicates dramatic changes in landfall frequency for the Gulf Coast on timescales of centuries to millennia, driven by changes in atmospheric circulation. This study will help delineate the temporal and spatial extent of these changes by extending sedimentary studies to the far southern Caribbean. Past climate conditions will be ascertained from a pollen analysis conducted on the cores and from published records, while laboratory analyses of magnetic susceptibility, electric resistivity, organic content, and grain size will be used to identify hurricane-generated layers. Chronological control will be by radiocarbon dating. Extending the proxy hurricane record to unstudied Caribbean areas will facilitate a clearer understanding of long-term hurricane behavior on a regional basis, while connecting the hurricane and climatic records will improve our understanding of the relationship between the two. Investigating hurricane activity as an interactive component of the larger circulation patterns facilitates untangling the complex connections. Since property damage and loss of life in the Caribbean and the United States resulting from the shift in the frequency and location of hurricane paths since the mid 1990s has been tremendous, any increased understanding of the mechanisms controlling the location and frequency of landfall will be of great societal value. The clarification of the role hurricanes play in the North Atlantic climate system and the way these relationships respond to changing climatic conditions is a critical step towards developing an effective societal response to this serious natural hazard.