Numerical modeling and field evidence of coastal overwash in southern New England from Hurricane Bob and implications for paleotempestology

In this paper, we examine the use of coastal overwash modeling in conjunction with geological proxy techniques to provide a more comprehensive tool for paleotempestology. Southern New England, which lies in the path of north tracking hurricanes, has been a prime location for paleotempestological studies. Hurricane Bob of 1991 is the most recent landfall in this region and has the most comprehensive data for model assessment and validation. Using the hurricane track, central pressure, and radius of maximum wind as input, a collection of four interoperable model components simulates the meteorological conditions, astronomical tides and storm surge, ocean and coastal waves, and the surf zone processes and runup onto dry land. The computed surface pressure, winds, waves, and water levels give very good agreement with data from weather stations, moored buoys, and tide gauges near the track and in the zone of maximum wind. The validated wave conditions and storm water levels define the boundary conditions for coastal overwash modeling, and the results show strong correlation with aerial photographs and sedimentary records at five sites near the landfall. The results provide modern analogs for the interpretation of early hurricane landfalls in southern New England that lack an instrumental record. Reconstruction of paleohurricanes will require geological proxy data at multiple locations for the multivariate inverse analysis with uncertain paleotopography and storm characteristics.