HR: 14:45h
AN: OS13A-05 INVITED     [Abstracts]
TI: Reconstructing Holocene Climate Variability and the Indonesian Throughflow in the Western Equatorial Pacific
AU: * Rosenthal, Y
EM: rosentha@marine.rutgers.edu
AF: Institute for Marine and Coastal Sciences, and Department of Geology, Rutgers University 71 Dudley Road, New Brunswick, NJ 08901 United States
AU: Oppo, D W
EM: doppo@whoi.edu
AF: Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543 United States
AU: Linsley, B
EM: blinsley@albany.edu
AF: Department of Earth and Atmospheric Sciences, ES 351, University at Albany-SUNY, 1400 Washington Ave, Albany, NY 12222 United States
AU: Djajadihardja, Y S
EM: iyung24@yahoo.com
AF: Indonesian Ministry of Science and Technology, J1 M.H. Thamarin 8 Jakarta, Jakarta, 10340 Indonesia
AU: Ridlo, A
EM: aridlo@webmail.bppt.go.id
AF: Indonesian Ministry of Science and Technology, J1 M.H. Thamarin 8 Jakarta, Jakarta, 10340 Indonesia
AU: Syamsudin, F
EM: fadli@ocean.hiroshima-u.ac.jp
AF: Indonesian Ministry of Science and Technology, J1 M.H. Thamarin 8 Jakarta, Jakarta, 10340 Indonesia
AB: The Indonesian Throughflow (ITF) is an important component of modern tropical climate and yet we have very limited understanding of its long term variability. Instrumental data indicate that the ITF modifies the heat and freshwater budgets and the air-sea heat fluxes of the Pacific and Indian Oceans, and may exercise a role in the ENSO and Asian monsoon. The ITF has also been noted as an important current for transferring climate signals and their anomalies around the world's oceans in part because it transports warm water from about ~5°N in the WPWP through the Indonesian Seas, into the Indian Ocean at ~12°S. Although we now have a more complete understanding of interannual variations in the ITF over the last several ENSO cycles, nothing is known about longer term, lower frequency ITF variations. Our method for reconstructing the Holocene history of the ITF is based on the strong correlation between thermocline temperatures, ITF transport through the Makassar Strait and the state of ENSO/ WPWP observed in the modern ocean ( Ffield et al., 2000). We are studying gravity and multi cores spanning the depth range of the main ITF (300-700m) from key locations within the Indonesian Seaway. Our goal is to use paired planktic and benthic δ¹⁸O and Mg/Ca analyses along depth transects to reconstruct changes in the hydrographic structure of the upper ocean in this region. So far we have generated two low-resolution (every 8cm) records of both planktonic ( Globigerinoides rubber) and benthic ( Cibicidoides sp.) δ¹⁸O and Mg/Ca from thermocline depth cores on opposite sides of the Makassar Strait. The paired δ¹⁸O and Mg/Ca records show the utility of this method to provide new and potentially exciting insights on the behavior of the thermocline in the Makassar Strait during the deglaciation and the Holocene, and by inference also on long-term ENSO dynamics. The preliminary results suggest that comparable amplitude millennial-scale changes in Makassar Strait thermocline depth occurred both during the deglaciation and the Holocene. Furthermore, the new records suggest that past millennial-scale changes in ITF transport might have been substantially larger than the observed interannual variability.
DE: 4231 Equatorial oceanography
DE: 4536 Hydrography and tracers
DE: 4924 Geochemical tracers
SC: Ocean Sciences [OS]
MN: Fall Meeting 2005