HR: 16:20h
AN: PP14A-02 INVITED    [Abstracts]
TI: The Indian Monsoon Variability during the Holocene: New Speleothem Records from the Core Monsoon Zone of India
AU: * Sinha, A
EM: asinha@usc.edu
AF: California State University Dominguez Hills, 1000 E. Victoria, Carson, CA 90747, United States
AU: Stott, L
EM: Stott@usc.edu
AF: University of Southern California, 3651 Trousdale PKWY, Los Angeles, CA 90089, United States
AU: Cannariato, K
EM: cannaria@usc.edu
AF: University of Southern California, 3651 Trousdale PKWY, Los Angeles, CA 90089, United States
AU: Cheng, H
EM: cheng021@umn.edu
AF: University of Minnesota, 100 Union Street SE, Minneapolis, MN 55455, United States
AU: Edwards, R
EM: edwar001@umn.edu
AF: University of Minnesota, 100 Union Street SE, Minneapolis, MN 55455, United States
AB: The Indian summer monsoon (ISM) brings 80% of India and Southeast Asia's annual precipitation and is vital to sustaining the region's agriculture, which supports nearly a quarter of the world's population. Although considerable efforts have been focused to improve its seasonal to inter-annual predictive capabilities, the potential for decade to century scale departures from the normal monsoon precipitation pattern poses one of the most significant risks to human health and welfare in the ISM dominated regions. Meteorological records of ISM (available since 1850 AD) document droughts on inter-annual to sub-decadal timescales but are too short to asses whether longer and/or more severe intervals of monsoon failures occurred during the Holocene. The goals of our work are to characterize the full spectrum of the longer-term monsoon variability, particularly on the societal time-scales, and to compare this with the instrumental and historic record from the last century in order to evaluate the potential for larger or more extended periods of monsoon failure. We are approaching these goals by using precisely dated and near-annually resolved oxygen isotope records of the speleothems collected from a suite of caves throughout the core monsoon zone of India. We present new, well-dated, speleothem records from north, central, and north-east India that document past monsoon variations spanning much of the Holocene. To a large extent, our records confirm the previous marine based reconstructions of ISM that suggest that the episodes of rapid monsoon changes in Holocene coincided with major shifts in North Atlantic temperatures. Our data also suggest that significant century-scale decreases in monsoon rainfall also took place during the early to mid-Holocene, a period of generally enhanced monsoon strength. The centennial scale departures in our reconstructions appear to be more severe than any change observed in last 150 years. Our ISM reconstructions during the Late Holocene (600 to 1500 AD) interval, which spans the Medieval Warm Period (MWP) and the earliest portion of the Little Ice Age (LIA), indicates that the short instrumental record of ISM seriously underestimates the magnitude of monsoon rainfall variability. Periods of severe drought, lasting decades, occurred during the 14th and mid 15th centuries and coincided with several of India's most devastating famines.
DE: 1635 Oceans (1616, 3305, 4215, 4513)
DE: 1836 Hydrological cycles and budgets (1218, 1655)
DE: 4900 PALEOCEANOGRAPHY (0473, 3344)
DE: 4901 Abrupt/rapid climate change (1605)
DE: 8408 Volcano/climate interactions (1605, 3309)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting