HR: 17:30h
AN: B34B-07    [Abstracts]
TI: High-Resolution Paleotempestology: Proxy Models for Reconstructing Interannual-Decadal Variations in Pre-Historic Tropical Cyclone Frequency and Intensity
AU: * Frappier, A B
EM: a.frappier@unh.edu
AF: Climate Change Research Center, Institute for the Study of Earth, Oceans, and Space, and Dept. of Earth Sciences, University of New Hampshire, 346 Morse Hall, Durham, NH 03824 United States
AU: Sahagian, D
EM: dork.sahagian@lehigh.edu
AF: Environment Initiative and Dept. of Earth Sciences, Lehigh University, 31 Williams Drive, Bethlehem, PA 18015 United States
AU: Carpenter, S J
EM: scott-j-carpenter@uiowa.edu
AF: Center for Global and Regional Environmental Research and Dept. of Geoscience, The University of Iowa, 121 Trowbridge Hall, Iowa City, IA 52242-1379 United States
AU: Gonz lez, L A
EM: lgonzlez@ku.edu
AF: Department of Geology, University of Kansas, 1475 Jayhawk Blvd., Rm. 120, Lawrence, KS 66045-7613 United States
AU: Frappier, B R
EM: frappier@unh.edu
AF: Department of Natural Resources, University of New Hampshire, 215 James Hall, Durham, NH 03824 United States
AB: Tropical cyclones (including hurricanes, typhoons, and cyclones) are among the most deadly and destructive natural hazards. As coastal populations and infrastructure in affected areas grow, the impact of these storms is sure to increase. On the other hand, the impact of global climate change on tropical cyclone activity remains uncertain and highly controversial. Recent research suggests that the destructive power of tropical cyclones in the Atlantic and north Pacific has increased substantially in recent decades in response to global warming. Related work also suggests that global tropical cyclone activity may be an important feedback mechanism in the planetary heat transport system that works to stabilize tropical temeratures and de-stabilize polar temperatures. In this century, climate change scenarios project that ocean-atmosphere conditions will become increasingly different from the 20th century for which the best historial and meteorological records of tropical cyclones are available. Geo-biologic proxies for paleotempestology can extend the historical record of tropical cyclone activity, enabling hypothesis testing across a wider array of climate boundary conditions. We present a 23-year tropical stalagmite record of recent stable isotope variations at monthly-weekly temporal resolution contains abrupt low excursions in the stable oxygen isotope ratio (δ¹⁸O value) of calcite that correspond temporally with recent historical tropical cyclones in the vicinity of the cave. Using logistic regression, we developed a statistical model to detect the proxy signature of tropical cyclone precipitation events in high-resolution speleothem stable isotope records can be used to reconstruct interannual-decadal variations in pre-historic storm frequency. The model reliably identified eight of the ten historically known tropical cyclone proxy signals in this record using the measurable parameters δ¹⁸O value, δ¹³C value, and single point changes in δ¹⁸O value; the model incorrectly classified only one of nearly 1200 non-storm sampling points. We also present a preliminary model to reconstruct the intensity of individual storms from the amplitude of δ¹⁸O value excursions. High-resolution speleothem stable isotope records thus may prove a useful new source of data in the effort to elucidate the controversial associations between highly variable tropical cyclone activity and the dynamic range of Quaternary climate.
DE: 0454 Isotopic composition and chemistry (1041, 4870)
DE: 0468 Natural hazards
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1694 Instruments and techniques
DE: 3344 Paleoclimatology (0473, 4900)
SC: Biogeosciences [B]
MN: Fall Meeting 2005