HR: 0800h
AN: OS31A-0561    [Abstracts]
TI: Extending Observational Volume and Heat Transport Records of the Indonesian Throughflow Using Repeat Expendable Bathythermograph (XBT) Lines
AU: * Vranes, K
EM: kvranes@ldeo.columbia.edu
AF: Department of Geology, University of Montana, 32 Campus Dr. #1296, Missoula, MT 59812
AU: Gordon, A
EM: agordon@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, P.O. Box 1000 61 Route 9W, Palisades, NY 10964
AU: Susanto, D
EM: dwi@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, P.O. Box 1000 61 Route 9W, Palisades, NY 10964
AB: The Indonesian Throughflow (ITF) is the only tropical link between ocean basins on the planet, carrying roughly 10\times 10$^{6}$ m$^{3}$/s (10 Sv) of thermocline water from the Pacific Ocean to the Indian Ocean. The ITF varies on interannual and decadal time scales, forced by ENSO, the Asian monsoons and interannual climate variability in the Indian Ocean basin. To date, direct current measurements of the ITF have been limited to two years duration, which is not enough to fully describe this Pacific-to-Indian connection on long-period scales. Recent measurements taken from December 1996 to July 1998 in the Makassar Strait of the Indonesian seas provide a detailed vertical and temporal picture of the ITF through its main channel, but only provide 1.7 years of record. Temperature data from a repeat expendable bathythermograph (XBT) program have been collected between Shark Bay, Australia and Sunda Strait between Sumatra and Java, Indonesia since 1982. This repeat line is perpendicular to the path of ITF outflow into the Indian Ocean South Equatorial Current at 12§S, allowing for geostrophic calculations of ITF volume transport into the Indian Ocean. A geostrophic transport time series is constructed from the Australia-Indonesia repeat XBT line and compared to the Makassar time series, finding excellent correlations for the 1.7-year duration of the Makassar series. It is inferred that the repeat XBT line may serve as an appropriate proxy record for interior ITF flow, extending the observational record of the ITF for at least two decades. The twenty-year record of ITF flow is most strongly influenced by ENSO, but is significantly influenced by other climatic process.
UR: http://www.earthinstitute.columbia.edu/flash/itf2004.html
DE: 4203 Analytical modeling
DE: 4504 Air/sea interactions (0312)
DE: 4522 El Ni¤o
DE: 4532 General circulation
DE: 1635 Oceans (4203)
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting