HR: 1330h
AN: PP22A-1192    [PDF]
TI: Linking Surface Hydrology in the Tropical Indian Ocean, Ocean Circulation, and Atmospheric Methane Over the Last two Climatic Cycles
AU: * Waelbroeck, C
EM: claire.waelbroeck@lsce.cnrs-gif.fr
AF: LSCE, Domaine du CNRS, bat.12, Gif-sur-Yvette, 91198 France
AU: Chappellaz, J
EM: jerome@lgge.obs.ujf-grenoble.fr
AF: LGGE, 54, rue Moliere, St-Martin d'Heres, 38402 France
AU: Parrenin, F
EM: Frederic.Parrenin@notos.cst.cnes.fr
AF: LEGOS, 18, av. E. Belin, Toulouse, 31400 France
AU: Ferrer, M
EM: mfcqam@iiqab.csic.es
AF: CSIC, Jordi Girona, Barcelona, 08034 Spain
AU: Levi, C
EM: levi@lsce.cnrs-gif.fr
AF: Rudgers University, Dudley Road, 71, New Brunswick, NJ 08901 United States
AU: Shackleton, N
EM: njs5@cam.ac.uk
AF: Godwin Laboratory, Pembroke Street, Cambridge, CB2 3SA United Kingdom
AU: Grimalt, J
EM: jgoqam@iiqab.csic.es
AF: CSIC, Jordi Girona, Barcelona, 08034 Spain
AU: Labeyrie, L
EM: labeyrie@lsce.cnrs-gif.fr
AF: LSCE, Domaine du CNRS, bat.12, Gif-sur-Yvette, 91198 France
AU: Jouzel, J
EM: jouzel@lsce.saclay.cea.fr
AF: LSCE, Domaine du CNRS, bat.12, Gif-sur-Yvette, 91198 France
AB: Core MD 98-2165 (9$\deg$38'96 S, 118$\deg$20'31 E, 2100 m) from the tropical Indian Ocean has been studied at a time resolution of about 200 y over the two last climatic cycles within the POP project. Oxygen and carbon isotopic composition ($\delta$$^{18}$O and $\delta$$^{13}$C) of benthic and planktonic foraminifera has been measured. The benthic d18O record is remarkably similar to Antarctica ice deuterium ($\delta$D) or $\delta$$^{18}$O records. 15 AMS $^{14}$C dates covering the last 26 kyrs allowed us to verify that our benthic $\delta$$^{18}$O record is perfectly synchronous with the ice records. This finding indicates that the impressive similarity found between a benthic $\delta$$^{18}$O record from the Iberian Margin and Vostok $\delta$D (Shackleton, 2000) between 24 and 64 kyrs BP, is not restricted to this particular deep sea core and to marine isotopic stage 3. Correlating our high resolution benthic $\delta$$^{18}$O records to Dome Fuji ice $\delta$$^{18}$O record dated by the inverse approach of Parrenin et al. (2001), we obtain a high resolution marine time scale which is consistent with the Antarctic ice cores time scales. Moreover, the error on the relative age of the marine versus ice core records is necessarily lower than the duration of the millennial events recognised in both records, hence yielding a great improvement in our ability to compare marine and ice records over the last two to three climatic cycles. In this new marine chronology, we examine the relative timing of changes in surface and deep-water variability in the tropical Indian Ocean with respect to the air temperature and atmospheric methane concentration records from Antarctic ice cores. Our results highlight a tight correspondence between sea surface salinity in the tropics and atmospheric methane concentration. In contrast, the millennial scale climatic variability characterising glacial periods does not exhibit a clear relationship between sea surface salinity in the tropical Indian Ocean and atmospheric methane concentration.
DE: 1620 Climate dynamics (3309)
DE: 4215 Climate and interannual variability (3309)
DE: 4267 Paleoceanography
DE: 4283 Water masses
DE: 9340 Indian Ocean
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2003 Fall Meeting