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abstracts
Coherence between the Asian monsoon and Indonesian hydrology during the past two millennia
Jessica Tierney, Delia Oppo, James Russell, Braddock Linsley, Yair Rosenthal
The West Pacific Warm Pool (WPWP) is the largest zone of deep convection on earth, and thus a major source of heat and water vapor to the global atmosphere. Shifts in the location and intensity of convection in the WPWP dramatically affect local precipitation, and – through modification of Hadley and Walker circulation – global atmospheric heating and circulation. However, mechanisms of hydrologic change in the WPWP are poorly understood, and paleohydrologic variability in this region, especially on decadal-to-millennial scales, is scarcely constrained. To better understand hydrology in this critical tropical region, we use hydrogen isotopic ratios on terrestrial higher plant leaf waxes (δDleaf wax) in marine sediments to infer centennial-scale changes in rainfall amount in Southwest Sulawesi, Indonesia during the last two millennia. Our data indicate drier conditions during the Medieval Warm Period (1000-1300 AD) and the Roman Warm Period (0-400 AD). The Little Ice Age (1400-1850 AD) appears to be the wettest interval during the past two millennia, in agreement with existing δ18O of seawater (δ18Osw) data from the Makassar Strait. Notably, δDleaf wax resolves centennial-scale trends in precipitation that are antiphased with a speleothem-based rainfall reconstruction from Southeast Asia. This relationship suggests that migrations of the Inter-tropical Convergence Zone (ITCZ) coupled with changes in Asian monsoon strength were major influences on Indonesian hydrology during the past 2000 yr.
Jessica Tierney, Department of Geological Sciences, Brown University,Box 1846 324 Brook St., Providence, RI 02912, United States, Jessica_Tierney@brown.edu
Delia Oppo, Woods Hole Oceanographic Institution, Department of Geology and Geophysics, United States
James Russell, Brown University, Department of Geological Sciences, United States
Braddock Linsley, University of Albany-State University of New York, Department of Atmospheric and Environmental Sciences, United States
Yair Rosenthal, Rutgers, The State University, Institute of Marine and Coastal Sciences and Department of Earth and Planetary Sciences, United States
Session: F3: Global Earth-System Dynamics
Download Talk:
> YSM09_OralF_JessicaTierney.pdf
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