Possible solar forcing of 400-year wet–dry climate cycles in northwestern China |
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| Authors: | Jinglu Wu Zicheng Yu Hai’Ao Zeng Ninglian Wang |
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| Institution: | (1) Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA 95039-9644, USA;(2) University of Wyoming, Laramie, WY 82071, USA;(3) University of California Davis, Davis, CA 95616, USA;(4) University of Tromso, 9037 Tromso, Norway;(5) Department of Earth Science, University of Bergen, 5007 Bergen, Norway;(6) University of New Hampshire, Durham, NH 03824-3589, USA;(7) United States Geological Survey, Woods Hole, MA 02543, USA;(8) United States Geological Survey, Menlo Park, CA 94025, USA |
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| Abstract: | Here we present a multi-proxy paleolimnological record from a closed-basin lake (Ebinur Lake) in northwestern China to investigate
climate change in this arid region during the last 1,500 years. The 120-cm long sediment core was dated by AMS radiocarbon
and 210Pb methods. The fine-grained clay sediments contain 3–17% organic matter (OM) and 9–31% carbonate, and are interrupted by
multiple sand and silt layers. These sand/silt layers, having consistently low OM, were found at 700–800, 1000–1100, 1300–1400,
and 1700–1750 a.d., with a time spacing of 300–400 years. We interpret that the low OM sand/silt layers were deposited during higher lake levels
caused by increased river inflow from the surrounding mountains during wet climate intervals. This interpretation is supported
by concurrent decreases in δ
18O and δ
13C of bulk carbonate and in carbonate content. Wet climate intervals at 700–800 a.d. and at 1700–1750 a.d. also correlate with elevated snow accumulation and low δ
18O from Guliya ice core on the NW Tibetan Plateau, both regions strongly influenced by the westerlies. This approximate 400-year
periodicity of wet–dry climate oscillations appear to correlate with solar activity as shown by atmosphere 14C concentration and with paleo-moisture records in interior North America. Our results suggest that solar activities might
have played a significant role in driving wet–dry climate oscillations at centennial scales in the interior of Eurasian continent. |
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