title: Hydroclimate of the western Indo-Pacific Warm Pool during the past 24,000 years.
abstract: The Indo-Pacific Warm Pool (IPWP) is a key site for the global hydrologic cycle, and modern observations indicate that both the Indian Ocean Zonal Mode (IOZM) and the El Niño Southern Oscillation exert strong influence on its regional hydrologic characteristics. Detailed insight into the natural range of IPWP dynamics and underlying climate mechanisms is, however, limited by the spatial and temporal coverage of climate data. In particular, long-term (multimillennial) precipitation patterns of the western IPWP, a key location for IOZM dynamics, are poorly understood. To help rectify this, we have reconstructed rainfall changes over Northwest Sumatra (western IPWP, Indian Ocean) throughout the past 24,000 y based on the stable hydrogen and carbon isotopic compositions (δD and δ(13)C, respectively) of terrestrial plant waxes. As a general feature of western IPWP hydrology, our data suggest similar rainfall amounts during the Last Glacial Maximum and the Holocene, contradicting previous claims that precipitation increased across the IPWP in response to deglacial changes in sea level and/or the position of the Intertropical Convergence Zone. We attribute this discrepancy to regional differences in topography and different responses to glacioeustatically forced changes in coastline position within the continental IPWP. During the Holocene, our data indicate considerable variations in rainfall amount. Comparison of our isotope time series to paleoclimate records from the Indian Ocean realm reveals previously unrecognized fluctuations of the Indian Ocean precipitation dipole during the Holocene, indicating that oscillations of the IOZM mean state have been a constituent of western IPWP rainfall over the past ten thousand years.
authors: Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125;Biodiversity and Climate Research Centre (BiK-F) and Senckenberg Gesellschaft für Naturforschung, D-60325 Frankfurt, Germany; eva.niedermeyer@senckenberg.de.
authors: Eva M
authors: EM
authors: Niedermeyer
authors: Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125;
authors: Alex L
authors: AL
authors: Sessions
authors: Department of Earth Sciences, University of Southern California, Los Angeles, CA 90089; and.
authors: Sarah J
authors: SJ
authors: Feakins
authors: MARUM-Center for Marine Environmental Sciences, University of Bremen, D-28359 Bremen, Germany.
authors: Mahyar
authors: M
authors: Mohtadi
mesh_terms: D002247:Carbon Isotopes / Q000032:analysis; D057231:Climate Change / Q000266:history* / Q000706:statistics & numerical data; D003903:Deuterium / Q000032:analysis; D059000:El Nino-Southern Oscillation; D049690:History, Ancient; D019156:Indian Ocean; D007214:Indonesia; D010944:Plants / Q000737:chemistry*; D011891:Rain; D014872:Water Movements; D014885:Waxes / Q000737:chemistry
chemical_list: D002247:Carbon Isotopes; D014885:Waxes; D003903:Deuterium
keywords: Indonesia; plant wax δ13C; plant wax δD