Paleotempestology

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Paleotempestology is the study of past tropical cyclone activity by means of geological proxies. Examples of proxies include overwash deposits preserved in the sediments of coastal lakes and marshes, microfossils such as foraminifera, pollen, diatoms, dinoflagellates, phytoliths contained in coastal sediments, wave-generated or flood-generated sedimentary structures or deposits (called tempestites) in marine or lagoonal sediments, storm wave deposited coral shingle, shell, sand and shell and pure sand shore parallel ridges, oxygen isotopic ratios of hurricane rainfall in shallow-water corals and speleotherms, and tree rings. The method of using overwash deposits preserved in coastal lake and marsh sediments is adopted from earlier studies of paleotsunami deposits. Both storms and tsunamis leave very similar if not identical sedimentary deposits in coastal lakes and marshes and differentiating between the two in a sedimentary record can be difficult.

The first studies to examine prehistoric records of tropical cyclones occurred in Australia and the South Pacific during the late 1970s and early 1980s. These studies examined multiple shore parallel ridges of coral shingle or sand and marine shells. As many as 50 ridges can be deposited at a site with each representing a past severe tropical cyclone over the previous 6,000 years. Tsunamis are not known to deposit multiple sedimentary ridges and therefore these features can be more easily attributed to a past storm at any given site.

Isotope studies in speleothems and tree rings offers a means by which higher resolution records of long-term tropical cyclone histories can be attained. Unlike the isotope records, the sedimentary records are too coarse in their resolution to register quasi-cyclic activity at decadal to centennial scales. These higher resolution records therefore offer a means for possibly differentiating between the natural variability of tropical cyclone behaviour and the effects of anthropogenically induced global climate change.

The term paleotempestology was coined by Prof. Kerry Emanuel of MIT.

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Baines, G. B. K and McLean, R. F. (1976). Sequential studies of hurricane deposit evolution at Funafuti Atoll. Marine Geology; 21: M1-M8.
Rhodes, E.G.; Polach, H.A.; Thom, B.G.; Wilson, S.R. (1980). Age structure of Holocene coastal sediments, Gulf of Carpentaria, Australia. Radiocarbon; 22: 718-727.
Chappell, J.; Chivas, A; Rhodes, E. and Wallensky, E. (1983). Holocene palaeo-environmental changes, central to north Great Barrier Reef inner zone. BMR Journ. Aust. Geol and Geophys; 8: 223-235.
Nott, J.F. (2004). Palaeotempestology – a review and implications for risk assessment. Environment International, 30, 433-447.
Liu, K.-b. (2004) Paleotempestology: Principles, Methods, and Examples from Gulf Coast Lake Sediments, in R. J. Murnane and K.-b. Liu (Eds.), Hurricanes and Typhoons: Past, Present, and Future, pp. 13-57. Columbia University Press, New York.
Donnelly, J. P. and T. Webb III (2004) Back-barrier Sedimentary Records of Intense Hurricane Landfalls in the Northeast United States, in R. J. Murnane and K.-b. Liu (Eds.), Hurricanes and Typhoons: Past, Present, and Future, pp. 58-98. Columbia University Press, New York.
Elsner, J. B. and A. Birol Kara (1999) Hurricanes of the North Atlantic: Climate and Society, pp 49-51, 378. Oxford University Press, New York.