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Woods Hole Oceanographic Institution

Nathalie Dubois

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Projects
» IPWP paleohygrology

» Central Pacific seismic

» South Pacific Gyre sediment grain size

» Organic chemistry of South Pacific Gyre Sediments

» Eastern Equatorial Pacific


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Enlarge image
Map of the IPWP. Red dots show the core tops chosen to be analysed. Yellow stars show the location of 2 speleothems records which we will compare our paleohydrologic reconstructions to (Borneo & Flores). (N. Dubois using ODV)


Hydrologic History of the Indo-Pacific-Warm Pool During the Last 25,000 Years

Collaborators:
Dr. Delia Oppo (WHOI), Prof. Tim Eglinton (ETHZ), Dr. Valier Galy (WHOI)

The aim of this project is to generate records of hydrologic changes from the Indo-Pacific Warm Pool (IPWP), the largest reservoir of warm surface water on Earth and a major source of heat for the global atmosphere.

We will measure compound-specific hydrogen and carbon isotopes of terrestrial longchain leaf wax fatty acids (δDwax and δ13Cwax) in marine sediment cores collected from continental margins around central and western Indonesian islands. The isotopes of terrestrial leaf plants will be used as tracers of water isotopes (δD) and aridity (δ13C) to reconstruct changes in the hydrologic cycle in the Indonesian region, during the last glacial maximum (LGM), the deglaciation, as well as during the Holocene and across late Holocene centennial-millennial events. These records will allow a better description of N-S migration, E-W migration, and expansion and contraction of precipitation centers.

Data will be interpreted in the context of model sensitivity studies, through a collaboration with Dr. Allegra LeGrande (GISS). Understanding how abrupt and gradual forcing influence tropical climate is critical for predicting future climate change. State-of-the-art models generally simulate weaker Walker and weaker but expanded Hadley circulations for greenhouse warming, although the amplitude of changes depends on the global sensitivity of the hydrologic cycle, which is uncertain.


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