Evidence for solar cycles in a late Holocene speleothem record from Dongge Cave, China - PubMed (original) (raw)

Evidence for solar cycles in a late Holocene speleothem record from Dongge Cave, China

Fucai Duan et al. Sci Rep. 2014.

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).

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Figures

Figure 1

Figure 1. Inter-comparison of stalagmite δ18O records from Dongge Cave, China during the late Holocene.

The DA record is from ref. , while the D4 record is from ref. . Black dots with horizontal error bars are MC-ICPMS U-Th ages (Table S1). Vertical gray bars denote the periods of weak monsoon events.

Figure 2

Figure 2. Inter-comparison between Dongge Cave Δ18O isotopic data and solar activity proxies.

The DAS Δ18O record (green) is plotted against the records of DA Δ18O (grey, A), Δ14C (orange, B), ΔSN (pink, C) and ΔTSI (purple, D). For the best correlation of two datasets, the chronology for the DAS record has been shifted older by 40 years and the one for the DA record younger by 47 years. Intensive solar activity (smaller Δ14C, larger ΔSN and ΔTSI) corresponds to a strong AM (smaller Δ18O). Vertical yellow bars indicate the weakest solar activity.

Figure 3

Figure 3. Continuous transform wavelet spectra for the DAS Δ18O (A) and Δ14C (B) data, and cross-wavelet spectrum between them (C).

Spectral power (variance) is shown by colors ranging from deep blue (weak) to deep red (strong). Gleissberg cycle at ~80 yr, Suess cycle at ~200 yr and unnamed cycle at ~340 yr are marked using horizontal, gray dashed lines. Black boundaries mark 95% significance level.

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References

    1. Wang B. et al. Northern Hemisphere summer monsoon intensified by mega-El Niño/southern oscillation and Atlantic multidecadal oscillation. Proc. Natl. Acad. Sci. USA 110, 5347–5352 (2013). - PMC - PubMed
    1. Krishnamurthy V. & Goswami B. N. Indian monsoon–ENSO relationship on interdecadal timescale. J. Climate 13, 579–595 (2000).
    1. Wang Y. J. et al. The Holocene Asian Monsoon: links to solar changes and North Atlantic climate. Science 308, 854–857 (2005). - PubMed
    1. Gupta A. K., Das M. & Anderson D. M. Solar influence on the Indian summer monsoon during the Holocene. Geophys. Res. Lett. 32, L17703, 1–4 (2005).
    1. Webster P. J. et al. Monsoons: Processes, predictability, and the prospects for prediction. J. Geophys. Res. 103, 14451–14510 (1998).

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