HR: 16:15h
AN: PP34B-02    [Abstracts]
TI: North Pacific Atmospheric Circulation and Tropical Teleconnections Over the Past 1500 Years From a Mt. Logan Ice Core
AU: * Osterberg, E C
EM: erich.c.osterberg@dartmouth.edu
AF: Dartmouth College Department of Earth Sciences, 6105 Sherman Fairchild Hall, Hanover, NH 03755, United States
AU: Mayewski, P A
EM: paul.mayewski@maine.edu
AF: University of Maine Climate Change Institute, Sawyer Environmental Research Building, Orono, ME 04469, United States
AU: Kreutz, K J
EM: karl.kreutz@maine.edu
AF: University of Maine Climate Change Institute, Sawyer Environmental Research Building, Orono, ME 04469, United States
AU: Fisher, D A
EM: fisher2@nrcan.gc.ca
AF: Geological Survey of Canada, 601 Booth Street, Ottawa, ON K1A 0E8, Canada
AU: Maasch, K
EM: krik.maasch@maine.edu
AF: University of Maine Climate Change Institute, Sawyer Environmental Research Building, Orono, ME 04469, United States
AU: Sneed, S B
EM: sharon.sneed@maine.edu
AF: University of Maine Climate Change Institute, Sawyer Environmental Research Building, Orono, ME 04469, United States
AB: A calibrated 1500 year-long glaciochemical proxy record for the strength of the wintertime (November-March) Aleutian Low (ALOW) from the Mt. Logan summit (PR Col; 5300 m a.s.l.) ice core [Na⁺] time series reveals a strong ALOW from ca. 650-900 A.D., ca. 1300-1550 A.D., and ca. 1700-1998 A.D., and a weaker ALOW from ca. 900-1300 A.D. and ca. 1550-1700 A.D. The proxy record was calibrated to instrumental sea-level pressure data using standard regression techniques, and verified using statistical, spectral, and spatial correlation analyses. The Mt. Logan ALOW proxy record shows strong similarities with sea surface temperature, precipitation, and glacier extent proxy records from the Pacific basin sensitive to the El Niño-Southern Oscillation, indicating a robust coupling between high-latitude and tropical Pacific climate during the late Holocene. The Medieval Warm Period was characterized by more persistent La Niña-like conditions (weak ALOW), while the Little Ice Age (LIA) was characterized by at least two intervals of more persistent El Niño-like conditions (strong ALOW; 1300-1550 A.D., 1700-1998 A.D.). The LIA intensification of the ALOW is similar to the LIA intensification of the Icelandic Low in the North Atlantic (based on the GISP2, Greenland ice core [Na⁺] calibrated proxy record) and the Amundsen Sea Low in the high-latitude South Pacific (based on the Siple Dome, West Antarctica ice core [Na⁺] calibrated proxy record).
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1637 Regional climate change
DE: 3344 Paleoclimatology (0473, 4900)
DE: 4922 El Nino (4522)
DE: 4932 Ice cores (0724)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting