title: Evidence for solar cycles in a late Holocene speleothem record from Dongge Cave, China.
abstract: The association between solar activity and Asian monsoon (AM) remains unclear. Here we evaluate the possible connection between them based on a precisely-dated, high-resolution speleothem oxygen isotope record from Dongge Cave, southwest China during the past 4.2 thousand years (ka). Without being adjusted chronologically to the solar signal, our record shows a distinct peak-to-peak correlation with cosmogenic nuclide (14)C, total solar irradiance (TSI), and sunspot number (SN) at multi-decadal to centennial timescales. Further cross-wavelet analyses between our calcite δ(18)O and atmospheric (14)C show statistically strong coherence at three typical periodicities of ~80, 200 and 340 years, suggesting important roles of solar activities in modulating AM changes at those timescales. Our result has further indicated a better correlation between our calcite δ(18)O record and atmospheric (14)C than between our record and TSI. This better correlation may imply that the Sun-monsoon connection is dominated most likely by cosmic rays and oceanic circulation (both associated to atmospheric (14)C), instead of the direct solar heating (TSI).
authors.affiliation: College of Geography Science, Nanjing Normal University, Nanjing 210023, China.
authors.forename: Fucai
authors.initials: F
authors.lastname: Duan
authors.affiliation: 1] College of Geography Science, Nanjing Normal University, Nanjing 210023, China [2].
authors.forename: Yongjin
authors.initials: Y
authors.lastname: Wang
authors.affiliation: High-Precision Mass Spectrometry and Environment Change Laboratory (HISPEC), Department of Geosciences, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Chuan-Chou
authors.initials: CC
authors.lastname: Shen
authors.affiliation: Department of Geography, School of Global Studies, University of Sussex, Brighton BN1 9QJ, UK.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: 1] Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China [2] Department of Geology and Geophysics, University of Minnesota, Minneapolis MN 55455, USA.
authors.forename: Hai
authors.initials: H
authors.lastname: Cheng
authors.affiliation: High-Precision Mass Spectrometry and Environment Change Laboratory (HISPEC), Department of Geosciences, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Chung-Che
authors.initials: CC
authors.lastname: Wu
authors.affiliation: High-Precision Mass Spectrometry and Environment Change Laboratory (HISPEC), Department of Geosciences, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Hsun-Ming
authors.initials: HM
authors.lastname: Hu
authors.affiliation: College of Geography Science, Nanjing Normal University, Nanjing 210023, China.
authors.forename: Xinggong
authors.initials: X
authors.lastname: Kong
authors.affiliation: College of Geography Science, Nanjing Normal University, Nanjing 210023, China.
authors.forename: Dianbing
authors.initials: D
authors.lastname: Liu
authors.affiliation: College of Geography Science, Nanjing Normal University, Nanjing 210023, China.
authors.forename: Kan
authors.initials: K
authors.lastname: Zhao