Department Lecture Series: Wallace

Mon, Feb 24, 2020, 4:00 pm to 5:00 pm
Guyot 220
All Welcome

Atlantic hurricanes threaten growing coastal property and populations along the U.S. coastline and Caribbean islands. Unfortunately, most of our predictive hurricane models are validated using an observational dataset that is short (1851-present) and biased. Little is known about the forces that alter hurricane activity on multi-decadal to centennial timescales. Coarse-grained hurricane-induced deposits preserved in blue holes throughout the tropical Atlantic offer high-resolution records of past hurricane activity stretching over thousands of years. Here we present near-annually resolved records of the frequency of intense hurricane events over the past 1500 years in blue holes from two islands in the Caribbean: South Andros Island and Long Island in The Bahamas. The records contain coarse-grained deposits dating to known historical hurricane strikes including Hurricane Joaquin in 2015. Both records suggest that the climate system was capable of producing multi-decadal and longer periods of very high levels of intense hurricane activity in the northern Caribbean. The patterns of hurricane activity reconstructed from South Andros match those from the Gulf of Mexico but are anti‐phased with records from New England. In contrast, the record from Long Island shows opposing patterns of hurricane activity to South Andros. The differences in these records suggest more localized controls on hurricane patterns in The Bahamas. We analyze a set of synthetic Atlantic hurricanes downscaled over the last millennium to constrain whether the centennial-scale variability observed at these sites is related to changing climate or random clustering of events under a stationary climate.