HR: 11:50h
AN: PP52A-07    [Abstracts]
TI: Stability of Pacific Decadal Oscillation over the last 270 years
AU: * Liu, J
EM: jl58@duke.edu
AF: Duke University, Division of Earth & Ocean Sciences, Nicholas School of the Environment and Earth Sciences, Durham, NC 27708, United States
AU: Crowley, T J
EM: thomas.crowley@ed.ac.uk
AF: University of Edinburgh, School of Geosciences,King's Buildings, Edinburgh, EH9 3JY, United Kingdom
AB: With the near certitude of the imprint of greenhouse warming on the global temperature record, climate scientists have shifted focus to more regional scale tests for greenhouse forcing in other records. A global warming signal has already been found in trends of mid-high northern latitude sea level pressure and zonal precipitation. But so far, there is no consensus on the effects of "future" greenhouse forcing on Pacific Decadal Oscillation–the most significant interdecadal oscillation in the largest ocean basin. Herein we test for a trend in the PDO by combining coral and tree ring proxies back 270 years. The high correlation (r=0.74) between these two proxies over a 147 years validation interval (1733-1880) justifies development of a joint proxy yielding a 0.91 correlation with the PDO from 1880 to 1992. The joint proxy indicates that the present state of the PDO is nearly "neutral", with no significant trend over the entire record. The stability implies that significant negative feedbacks identified for this mode are sufficiently strong to neutralize (so far) the effects of global warming on behavior of this mode.
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1635 Oceans (1616, 3305, 4215, 4513)
DE: 4220 Coral reef systems (4916)
DE: 4513 Decadal ocean variability (1616, 1635, 3305, 4215)
DE: 4920 Dendrochronology
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting