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Past dynamics of the Australian monsoon: precession, phase and links to the global monsoon
L. Beaufort1, S. van der Kaars2, F. C. Bassinot3, and V. Moron1,4
1CEREGE, CNRS-Universités Aix-Marseille, UMR 6635, Aix en Provence, France
2Centre for Palynology and Palaeoecology, School of Geography and Environmental Science, Monash University, Victoria, 3800, Australia
3LSCE, CEA-CNRS, Gif sur Yvette, France
4IRI, Columbia University, New York, USA
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Abstract. Past variations in the dynamics of the Australian monsoon have been
estimated from multi-proxy analysis of a core retrieved in the Eastern Banda
Sea. Records of coccolith and pollen assemblages, spanning the last 150,000
years, allow reconstruction of past primary production in the Banda Sea,
summer moisture availability, and the length of the dry season in Northern
Australia and Southeastern Indonesia. The amount of moisture available
during the summer monsoon follows typical glacial/interglacial dynamics with
a broad asymmetrical 100-kyr cycle. Primary production and length of the dry
season appear to be closely related, given that they follow the precessional
cycle with the same phase (August insolation). This indicates their
independence from ice-volume variations. The present inter-annual
variability of both parameters is related to El Niño Southern
Oscillation (ENSO), which modulates the Australian Winter Monsoon (AWM). The
precessional pattern observed in the past dynamics of the AWM is found in
ENSO and monsoon records of other regions. A marked shift in the monsoon
intensity occurring during the mid Holocene during a period of constant ice
volume, suggest that low latitude climatic variation precedes global ice
volume. This precessional pattern suggests that a common forcing mechanism
underlies low latitude climate dynamics, acting specifically and
synchronically on the different monsoon systems.
 Notice on Discussion StatusThe requested discussion paper has a corresponding peer-reviewed
final revised paper in the journal Climate of the Past (CP). You are
encouraged to refer to the final revised version. Final Revised Paper (CP) Discussion Paper (PDF, 3808 KB)
Citation: Beaufort, L., van der Kaars, S., Bassinot, F. C., and Moron, V.: Past dynamics of the Australian monsoon: precession, phase and links to the global monsoon, Clim. Past Discuss., 6, 1045-1076, doi:10.5194/cpd-6-1045-2010, 2010. Bibtex EndNote Reference Manager XML
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