title: Indian monsoon variability on millennial-orbital timescales.
abstract: The Indian summer monsoon (ISM) monsoon is critical to billions of people living in the region. Yet, significant debates remain on primary ISM drivers on millennial-orbital timescales. Here, we use speleothem oxygen isotope (δ(18)O) data from Bittoo cave, Northern India to reconstruct ISM variability over the past 280,000 years. We find strong coherence between North Indian and Chinese speleothem δ(18)O records from the East Asian monsoon domain, suggesting that both Asian monsoon subsystems exhibit a coupled response to changes in Northern Hemisphere summer insolation (NHSI) without significant temporal lags, supporting the view that the tropical-subtropical monsoon variability is driven directly by precession-induced changes in NHSI. Comparisons of the North Indian record with both Antarctic ice core and sea-surface temperature records from the southern Indian Ocean over the last glacial period do not suggest a dominant role of Southern Hemisphere climate processes in regulating the ISM variability on millennial-orbital timescales.
authors.affiliation: Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China.
authors.forename: Gayatri
authors.initials: G
authors.lastname: Kathayat
authors.affiliation: Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China.|Department of Earth Sciences, University of Minnesota, Minnesota 55455, USA.
authors.forename: Hai
authors.initials: H
authors.lastname: Cheng
authors.affiliation: Department of Earth Sciences, California State University Dominguez Hills, CA 90747, USA.
authors.forename: Ashish
authors.initials: A
authors.lastname: Sinha
authors.affiliation: Institut für Geologie, Universität Innsbruck, Innrain 52, A-6020 Innsbruck, Austria.
authors.forename: Christoph
authors.initials: C
authors.lastname: Spötl
authors.affiliation: Department of Earth Sciences, University of Minnesota, Minnesota 55455, USA.
authors.forename: R Lawrence
authors.initials: RL
authors.lastname: Edwards
authors.affiliation: Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China.
authors.forename: Haiwei
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China.
authors.forename: Xianglei
authors.initials: X
authors.lastname: Li
authors.affiliation: State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Yi
authors.affiliation: Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China.
authors.forename: Youfeng
authors.initials: Y
authors.lastname: Ning
authors.affiliation: Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710054, China.
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Cai
authors.affiliation: Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710054, China.
authors.forename: Weiguo Lui
authors.initials: WL
authors.lastname: Lui
authors.affiliation: Department of Earth Sciences, University of Cambridge, Downing Street, CB2 3EQ Cambridge, UK.|institute for Geology, Mineralogy &Geophysics, Ruhr-Universität Bochum, Universitätsstr, 150, 44801 Bochum, Germany.
authors.forename: Sebastian F M
authors.initials: SF
authors.lastname: Breitenbach