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The intertropical convergence zone modulates intense hurricane strikes on the western North Atlantic margin

July 1, 2016

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.

Publication Year 2016
Title The intertropical convergence zone modulates intense hurricane strikes on the western North Atlantic margin
DOI 10.1038/srep21728
Authors Peter J. van Hengstrum, Jeffrey P. Donnelly, Patricia L. Fall, Michael Toomey, Nancy A. Albury, Brian Kakuk
Publication Type Article
Publication Subtype Journal Article
Series Title Scientific Reports
Index ID 70188437
Record Source USGS Publications Warehouse
USGS Organization Eastern Geology and Paleoclimate Science Center