title: The intertropical convergence zone modulates intense hurricane strikes on the western North Atlantic margin.
abstract: Most Atlantic hurricanes form in the Main Development Region between 9°N to 20°N along the northern edge of the Intertropical Convergence Zone (ITCZ). Previous research has suggested that meridional shifts in the ITCZ position on geologic timescales can modulate hurricane activity, but continuous and long-term storm records are needed from multiple sites to assess this hypothesis. Here we present a 3000 year record of intense hurricane strikes in the northern Bahamas (Abaco Island) based on overwash deposits in a coastal sinkhole, which indicates that the ITCZ has likely helped modulate intense hurricane strikes on the western North Atlantic margin on millennial to centennial-scales. The new reconstruction closely matches a previous reconstruction from Puerto Rico, and documents a period of elevated intense hurricane activity on the western North Atlantic margin from 2500 to 1000 years ago when paleo precipitation proxies suggest that the ITCZ occupied a more northern position. Considering that anthropogenic warming is predicted to be focused in the northern hemisphere in the coming century, these results provide a prehistoric analog that an attendant northern ITCZ shift in the future may again return the western North Atlantic margin to an active hurricane interval.
authors.affiliation: Texas A&M University at Galveston, Department of Marine Sciences, Galveston, Texas, 77554.|Texas A&M University, Department of Oceanography, College Station, Texas, 77843.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: van Hengstum
authors.affiliation: Woods Hole Oceanographic Institution, Department of Geology and Geophysics, Woods Hole, Massachusetts, 02543, USA.
authors.forename: Jeffrey P
authors.initials: JP
authors.lastname: Donnelly
authors.affiliation: University of North Carolina Charlotte, Department of Geography and Earth Sciences, Charlotte, North Carolina, 28223, USA.
authors.forename: Patricia L
authors.initials: PL
authors.lastname: Fall
authors.affiliation: U.S. Geological Survey, Eastern Geology and Paleoclimate Science Center, Reston, VA, 20192.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Toomey
authors.affiliation: Antiquities, Monuments, and Museums Corporation/National Museum of The Bahamas, PO Box EE-15082, Nassau, The Bahamas.
authors.forename: Nancy A
authors.initials: NA
authors.lastname: Albury
authors.affiliation: Bahamas Underground, Marsh Harbour, Abaco Island, The Bahamas.
authors.forename: Brian
authors.initials: B
authors.lastname: Kakuk