Doctoral Dissertation Research: Tracking Donna Across the Northern Caribbean: Developing a Modern Analog Methodology for Paleotempestology

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The highly destructive hurricane season of 2005 intensified debate regarding the degree to which the number and intensity of hurricane and other severe storms were related to possibly significant changes in local, regional, and global climatic regimes. Attempts to study historical trends have been hampered by the fact that instrument-based climate records have existed only in relatively recent time periods. Paleotempestology can look to the proxy record to overcome the limitations of the instrumental record and can help to identify hurricane frequency changes that are not evident in the modern record. This doctoral dissertation research project will establish the first extensive modern analog study for paleotempestology by quantitatively assessing and characterizing the geomorphic and sedimentological impacts of Hurricane Donna across three northern Caribbean islands via the stratigraphic analysis of coastal lake sediment cores. Hurricane Donna directly struck the Caribbean island nations of Barbuda, Anguilla, and Acklins Island (Bahamas) as a severe category 4 hurricane in 1960 before making landfall in southern Florida and ravaging the U.S. Atlantic coast, causing tremendous destruction and casualties along its path. This study will test the hypothesis that Donna caused an overwash event in each of the three Caribbean islands, which would have left a detectable record in the form of overwash sand layers in the sediments of coastal back-barrier lakes. The stratigraphic record of Donna will be compared with those of other recent hurricanes of known intensities that also impacted the islands, so that the modern relationship between hurricane intensity and proxy signal strength (e.g., sand layer thickness) can be established. Using multiple geological and biological proxies in concert with radio-isotopic dating (14C and 137Cs), the stratigraphic signature of Hurricane Donna will be identified and used to calibrate the proxy records of prehistoric hurricane strikes in an effort to reconstruct a late-Holocene history of hurricane activities for the northern Caribbean. The reconstruction of a long-term hurricane history for the northern Caribbean will allow, in conjunction with other ongoing paleotempestological studies in other parts of the Caribbean, for the interpretation of basin-wide shifts in hurricane patterns that in turn can be used to decipher the forcing mechanisms behind them. This project is significant as it contributes to the young science of paleotempestology by establishing a comprehensive modern analog methodology that is essential to the calibration and interpretation of the proxy records. This project will also establish the first proxy records of prehistoric hurricane strikes for the northern Caribbean, thereby filling a large gap in the current knowledge and data network for Atlantic paleohurricanes. These new proxy records from the northern Caribbean will be vital for testing the Bermuda High Hypothesis, which is a cornerstone in the burgeoning field of paleotempestology. There are many practical applications for this study and they have far reaching relevance to the societies of the Caribbean region. There is a pressing need to understand the spatial and temporal variability of hurricane activity in the Caribbean and the climate mechanisms responsible for this variability. This study will produce long-term proxy records that are necessary for the calculation of hurricane return periods and annual landfall probabilities for the northern Caribbean region. These data have great societal value and can be used by local government officials in risk assessment and mitigation planning. Involvement of local researchers and school students in fieldwork will also contribute to science education and capacity building in these Caribbean island nations.