HR: 1340h
AN: PP33C-1600    [Abstracts]
TI: North Pacific Climate Variability in Ice Core Accumulation Records From Eclipse Icefield, Yukon, Canada
AU: * Yalcin, K
EM: yalckapl@isu.edu
AF: Department of Geosciences, Idaho State University, Pocatello, ID 83209 United States
AU: Wake, C P
EM: cameron.wake@unh.edu
AF: Climate Change Research Center, University of New Hampshire, Durham, NH 03824 United States
AU: Kreutz, K J
EM: karl.kreutz@maine.edu
AF: Climate Change Institute, University of Maine, Orono, ME 04469 United States
AB: Three annually dated ice cores from Eclipse Icefield, Yukon, Canada provide records of net accumulation spanning the last 100 to 500 years. The ice cores were dated by annual layer counting verified by reference horizons provided by radioactive fallout and volcanic eruptions. Annual layers become progressively thinner with depth in the Eclipse ice cores, requiring reconstruction of original annual layer thicknesses by correcting for ice creep. An empirical approach was used that is based on the observed layer thicknesses from annual layer counting of the Eclipse ice cores. Accumulation records are highly reproducible with 73% of the signal shared between the three cores. The accumulation time-series shows considerable decadal scale variability that can be related to climate regimes that characterize the North Pacific. For example, periods of high accumulation are noted from 1470-1500, 1540-1560, and 1925-1975. Periods of low accumulation are observed between 1500-1540, 1680-1780, and 1875-1925. The strongest multi-year drop in accumulation is seen between 1979 and 1984, although there are isolated years with lower accumulation. This drop in accumulation is possibly related to the 1977 regime shift in the Pacific Decadal Oscillation. However, PDO regime shifts are not always reflected in the accumulation time series, implying a non-linear response or modulation by other modes of climate variability such as ENSO. Its is noteworthy that the Eclipse accumulation time series is out of phase with the accumulation time series from nearby Mount Logan on all time scales for reasons to be investigated.
DE: 1637 Regional climate change
DE: 3305 Climate change and variability (1616, 1635, 3309, 4215, 4513)
DE: 3344 Paleoclimatology (0473, 4900)
DE: 4932 Ice cores (0724)
DE: 9355 Pacific Ocean
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005