HR: 0800h
AN: PP21C-1569    [Abstracts]
TI: Sea Surface Temperature Variability in the Southwest Tropical Pacific Since 1679 AD Derived From Coral Skeletal Geochemistry
AU: * DeLong, K L
EM: kdelong@marine.usf.edu
AF: College of Marine Science, University of South Florida, 140 7th Ave. South, St. Petersburg, FL 33701 United States
AU: Quinn, T M
EM: quinn@marine.usf.edu
AF: College of Marine Science, University of South Florida, 140 7th Ave. South, St. Petersburg, FL 33701 United States
AU: Taylor, F W
EM: fred@utig.ig.utexas.edu
AF: Institute for Geophysics, The John A. and Katherine G. Jackson School of Geosciences, The University of Texas at Austin, 4412 Spicewood Springs Rd., Austin, TX 78759 United States
AB: We present a reconstruction of sea surface temperature (SST) back to 1679 AD using Sr/Ca determinations in a Porites lutea coral collected offshore of Am/'{e}d/'{e}e Island, New Caledonia (22°29'S, 166°28'E). The ~ monthly Sr/Ca samples were extracted from the coral slabs along a path parallel to that used for previous stable isotopic studies (core 92-PA-A-1). The age model developed from the Sr/Ca time series was used to revise the previously published chronology of this core, which was based on seasonal δ¹⁸O variations. The revised chronology of the Amédée coral includes select sections from a companion core (core 92-PA-A-2) collected from the same coral colony. Annual extension rates average 0.99 ±0.44 cm/year (2σ), and varies from a low of 0.53 cm/year to a high of 1.87 cm/year; extension rates between overlapping paths and companion core paths agree within a few millimeters. The potential for kinetic effects on coral Sr/Ca signal was judged to be minimal based on the lack of correlation between annual extension rate and annual average Sr/Ca (r = -0.01, p < 0.01, n = 319). The local 33-year instrumental SST record was extended back to 1870 via calibration with a gridded SST product (HadISST1.1). SST's cooler than average occurred in the earliest 1700's, 1760-1780, 1815-1875, and 1937-1947. Several cool intervals coincide with known periods of volcanism: Pinatubo (1991), Krakatau (1883), and other events in the 1800's, early 1700's and late 1600's. Multi-taper (MTM) spectral analysis of the Sr/Ca time series revealed significant spectral power (99% CI) in the multi-decadal bands and a lack of spectral power at interannual bands; an MTM of the instrumental SST record showed similar results. Wavelet analysis of the Sr/Ca record revealed a strong concentration of spectral power in the multi-decadal (quasi-30 year band) in two intervals: 1900-1990 and 1725-1830. Spectral power in the multi-decadal band was strongest in the 20^th century.
DE: 4900 PALEOCEANOGRAPHY (0473, 3344)
DE: 4916 Corals (4220)
DE: 4954 Sea surface temperature
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005