HR: 11:05h
AN: PP12A-04    [Abstracts]
TI: Evidence for Decadal and Centennial Variability of Southwest Indian Monsoon Precipitation During the B$\o$lling-$\AA$ller$\o$d
AU: Sinha, A
EM: asinha@usc.edu
AF: Earth Sciences, California State University, Dominguez Hills, Carson, CA 90747 United States
AU: * Cannariato, K G
EM: cannaria@usc.edu
AF: Earth Sciences, University of Southern California, Los Angeles, CA 90089 United States
AU: Stott, L D
EM: stott@usc.edu
AF: Earth Sciences, University of Southern California, Los Angeles, CA 90089 United States
AU: Li, H
EM: hli@usc.edu
AF: Earth Sciences, University of Southern California, Los Angeles, CA 90089 United States
AU: You, C
EM: cfy20@mail.ncku.edu.tw
AF: Earth Sciences, National Cheng-Kung University, Taiwan, 701 Taiwan
AU: Cheng, H
EM: cheng021@umn.edu
AF: Geology and Geophysics, University of Minnesota, Minneapolis, MN 55455 United States
AU: Edwards, R L
EM: edwar001@tc.umn.edu
AF: Geology and Geophysics, University of Minnesota, Minneapolis, MN 55455 United States
AB: Nearly one quarter of all people living today are affected by the seasonal rainfall of the Southwest Indian Summer Monsoon. Meteorological records and historical accounts reveal sub-decadal intervals of reduced monsoon rainfall that resulted in droughts, crop failures, and extensive famines. However, little is known about how monsoon precipitation varied before the short instrumental record began. Furthermore, there are few terrestrial records of SW Indian Monsoon variability from within India. Here we present our first SW Indian Monsoon precipitation record from stalagmites collected from caves located throughout India. The oxygen isotopic composition of speleothem calcite is a proxy for monsoon precipitation variability that we use to extend the instrumental record back to the last deglaciation. We generated a thorium-230-dated ($\sim$11.6 to 15.6 ka) high-resolution stalagmite oxygen isotope record from Timta Cave in the western Himalayas that documents precipitation changes throughout the B$\o$lling-$\AA$ller$\o$d. While the lower and upper portions of the stalagmite grew at a rate such that our isotope record has a temporal resolution of $\sim$20 yr during the transitions into and out of the B$\o$lling-$\AA$ller$\o$d, the middle portion grew much more rapidly. This portion of the precipitation record has a resolution of $\sim$2.5 yr allowing us to assess decadal-to-interannual variability of the SW Indian Monsoon during the late B$\o$lling and early $\AA$ller$\o$d. Compared to the glacial and Younger Dryas, the SW Indian Monsoon was enhanced during the B$\o$lling-$\AA$ller$\o$d and apparently coupled to the East Asian Monsoon and North Atlantic climate on millennial time scales during the deglaciation. Additionally, multi-centennial precipitation variations within the B$\o$lling-$\AA$ller$\o$d may be correlative to the climate variations recorded in the Greenland ice cores. This work suggests that the high and low latitude climate systems are closely coupled on millennial and possibly centennial time scales. Significant decadal variability was recorded in the middle high-growth-rate interval. Periodicities of this precipitation variability are similar to those found in the modern instrumental record suggesting that climate dynamics similar to today may have been responsible.
DE: 3344 Paleoclimatology
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting