88th Annual Meeting (20-24 January 2008)

Monday, 21 January 2008
Variations of Atlantic tropical cyclones and climate change since the mid eighteenth century
Exhibit Hall B (Ernest N. Morial Convention Center)
Cary J. Mock, University of South Carolina, Columbia, SC; and M. Chenoweth, D. A. Glenn, S. F. Dodds, S. O. Holmberg, H. F. Young, J. Tanis, R. L. Murphy, L. J. Stroup, I. M. Altamirano, and C. W. Landsea
We present new results for the Atlantic Basin that extend time series prior to 1851 that are directly compatible and supplement the National Hurricane Center's HURDAT (Atlantic basin hurricane database), enabling robust statistical comparisons and linkages to important mechanisms of climate change. Historical documents used for reconstructing storms consist of data from ship logbooks, diaries, newspapers, and early instrumental records from more than 50 different archival repositories. Classification of storms were discriminated among tropical storms, hurricanes, major hurricanes, and non-tropical lows at least at tropical storm strength. The results detail the characteristics of several hundred storms, many of them newly documented. Continuous tropical cyclone series encompassing most of the western Atlantic Basin extend back to 1800, and four continuous regional hurricane series extend back to at least 1779. Results indicate that multidecadal behavior of tropical storms and hurricane frequencies dominates, but exhibit different temporal variability between subregions. For example, prominent active periods of tropical cyclones are evident along the southeast Atlantic Coast in the 1830s and 1890s, but parts of the Caribbean and Gulf coasts exhibit active periods more evident in the 1810s and 1820s. Paleoclimate and historical instrumental records of the AMO, Atlantic SSTs, West African rainfall, and ENSO indicate that different modes in these forcing mechanisms may explain some of the multidecadal behavior; however, particular synoptic-scale patterns in the latter part of the Little Ice Age, involving forcing from solar variability and perhaps volcanic eruptions, are also likely to have triggered seasons of abnormally high hurricane activity. Of particular attention, our presentation will also describe the active years along the coastal U.S. of 1806, 1815, 1837, 1838, and 1842; and individual major hurricanes with prominent societal impacts, including the closest major hurricane to ever pass New Orleans in 1812, and the critical re-evaluation of the Norfolk and Long Island hurricane in 1821.

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