title: East Asian summer monsoon precipitation variability since the last deglaciation.
abstract: The lack of a precisely-dated, unequivocal climate proxy from northern China, where precipitation variability is traditionally considered as an East Asian summer monsoon (EASM) indicator, impedes our understanding of the behaviour and dynamics of the EASM. Here we present a well-dated, pollen-based, ~20-yr-resolution quantitative precipitation reconstruction (derived using a transfer function) from an alpine lake in North China, which provides for the first time a direct record of EASM evolution since 14.7 ka (ka = thousands of years before present, where the "present" is defined as the year AD 1950). Our record reveals a gradually intensifying monsoon from 14.7-7.0 ka, a maximum monsoon (30% higher precipitation than present) from ~7.8-5.3 ka, and a rapid decline since ~3.3 ka. These insolation-driven EASM trends were punctuated by two millennial-scale weakening events which occurred synchronously to the cold Younger Dryas and at ~9.5-8.5 ka, and by two centennial-scale intervals of enhanced (weakened) monsoon during the Medieval Warm Period (Little Ice Age). Our precipitation reconstruction, consistent with temperature changes but quite different from the prevailing view of EASM evolution, points to strong internal feedback processes driving the EASM, and may aid our understanding of future monsoon behaviour under ongoing anthropogenic climate change.
authors.affiliation: MOE Key Laboratory of Western China's Environmental System, Lanzhou University, Lanzhou 730000, China.
authors.forename: Fahu
authors.initials: F
authors.lastname: Chen
authors.affiliation: Institute of Nihewan Archaeology Research, College of Resources and Environment, Hebei Normal University, Shijiazhuang 050024, China.
authors.forename: Qinghai
authors.initials: Q
authors.lastname: Xu
authors.affiliation: MOE Key Laboratory of Western China's Environmental System, Lanzhou University, Lanzhou 730000, China.
authors.forename: Jianhui
authors.initials: J
authors.lastname: Chen
authors.affiliation: 1] Department of Biology and Bjerknes Centre for Climate Research, University of Bergen, N-5020 Bergen, Norway [2] Environmental Change Research Centre, University College London, London WC1E 6BT, UK; and School of Geography and the Environment, University of Oxford, Oxford OX1 3QY, UK.
authors.forename: H John B
authors.initials: HJ
authors.lastname: Birks
authors.affiliation: MOE Key Laboratory of Western China's Environmental System, Lanzhou University, Lanzhou 730000, China.
authors.forename: Jianbao
authors.initials: J
authors.lastname: Liu
authors.affiliation: Institute of Nihewan Archaeology Research, College of Resources and Environment, Hebei Normal University, Shijiazhuang 050024, China.
authors.forename: Shengrui
authors.initials: S
authors.lastname: Zhang
authors.affiliation: MOE Key Laboratory of Western China's Environmental System, Lanzhou University, Lanzhou 730000, China.
authors.forename: Liya
authors.initials: L
authors.lastname: Jin
authors.affiliation: MOE Key Laboratory of Western China's Environmental System, Lanzhou University, Lanzhou 730000, China.
authors.forename: Chengbang
authors.initials: C
authors.lastname: An
authors.affiliation: Department of Biology and Bjerknes Centre for Climate Research, University of Bergen, N-5020 Bergen, Norway.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Telford
authors.affiliation: Institute of Nihewan Archaeology Research, College of Resources and Environment, Hebei Normal University, Shijiazhuang 050024, China.
authors.forename: Xianyong
authors.initials: X
authors.lastname: Cao
authors.affiliation: MOE Key Laboratory of Western China's Environmental System, Lanzhou University, Lanzhou 730000, China.
authors.forename: Zongli
authors.initials: Z
authors.lastname: Wang
authors.affiliation: MOE Key Laboratory of Western China's Environmental System, Lanzhou University, Lanzhou 730000, China.
authors.forename: Xiaojian
authors.initials: X
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005, China.
authors.forename: Kandasamy
authors.initials: K
authors.lastname: Selvaraj
authors.affiliation: Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China.
authors.forename: Houyuan
authors.initials: H
authors.lastname: Lu
authors.affiliation: Institute of Nihewan Archaeology Research, College of Resources and Environment, Hebei Normal University, Shijiazhuang 050024, China.
authors.forename: Yuecong
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Earth Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Zheng
authors.affiliation: MOE Key Laboratory of Western China's Environmental System, Lanzhou University, Lanzhou 730000, China.
authors.forename: Haipeng
authors.initials: H
authors.lastname: Wang
authors.affiliation: MOE Key Laboratory of Western China's Environmental System, Lanzhou University, Lanzhou 730000, China.
authors.forename: Aifeng
authors.initials: A
authors.lastname: Zhou
authors.affiliation: MOE Key Laboratory of Western China's Environmental System, Lanzhou University, Lanzhou 730000, China.
authors.forename: Guanghui
authors.initials: G
authors.lastname: Dong
authors.affiliation: MOE Key Laboratory of Western China's Environmental System, Lanzhou University, Lanzhou 730000, China.
authors.forename: Jiawu
authors.initials: J
authors.lastname: Zhang
authors.affiliation: MOE Key Laboratory of Western China's Environmental System, Lanzhou University, Lanzhou 730000, China.
authors.forename: Xiaozhong
authors.initials: X
authors.lastname: Huang
authors.affiliation: Department of Geography and Planning, University of Liverpool, Liverpool L69 3BX, UK.
authors.forename: Jan
authors.initials: J
authors.lastname: Bloemendal
authors.affiliation: MOE Key Laboratory of Western China's Environmental System, Lanzhou University, Lanzhou 730000, China.
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Rao