Rainfall history for the Hexi Corridor in the arid northwest China during the past 620 years derived from tree rings

Authors

  • Bao Yang,

    Corresponding author
    1. Key Laboratory of Desert and Desertification, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, 260 Donggang West Road, 730000 Lanzhou, China
    2. MOE Key Laboratory of West China's Environmental System College of Earth and Environment Sciences, Lanzhou University, Lanzhou, Gansu, China
    • Key Laboratory of Desert and Desertification, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, 260 Donggang West Road, 730000 Lanzhou, China.
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  • Chun Qin,

    1. Key Laboratory of Desert and Desertification, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, 260 Donggang West Road, 730000 Lanzhou, China
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  • Achim Bräuning,

    1. Institute of Geography, University of Erlangen, Kochstrasse 4/4, 91054 Erlangen, Germany
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  • Iris Burchardt,

    1. Institute of Geography, University of Erlangen, Kochstrasse 4/4, 91054 Erlangen, Germany
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  • Jingjing Liu

    1. Key Laboratory of Desert and Desertification, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, 260 Donggang West Road, 730000 Lanzhou, China
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Abstract

We present a 620-year long ring width record from the middle Qilian Mountains, where it is presently controlled by the Westerlies. The chronology was developed from Qilian juniper (Sabina przewalskii) growing at sites near the western distribution limit of the species in the northern Qilian Mountains, Gansu Province, China. A linear regression model between ring width and annual (July to June) precipitation accounts for 34.9% of the observed instrumental precipitation variance during the period 1952 to 2007. Spatial correlation analyses between the reconstruction and gridded precipitation data shows that the annual precipitation reconstruction captures regional climatic variations over the Qilian Mountains and the nearby Hexi Corridor. We also show the scaled standard chronology adjusted to the mean and variance of the instrumental data. Relatively wet periods are identified for AD 1390–1413, 1425–1450, 1530–1649, 1792–1920, 1937–1949 and 1980–1985. Dry conditions prevailed during AD 1414–1424, 1451–1529, 1650–1791, 1921–1936, 1950–1979 and 1986–2007. In comparison with the regression-based reconstruction, the scaled reconstruction indicates considerably wetter conditions during 1390–1413, 1425–1450, 1570–1630 and 1790–1920. The interval AD 1451–1529 was the most intense and longest drought epoch in the Hexi Corridor over the past six centuries. This drought was not only recorded in the Qilian Mountains but also occurred in northern and eastern China. It might be caused by a substantial weakening of the Asian summer monsoon induced by the joint effects of solar and volcanic activities at that time. Our results also suggest that the Hexi Corridor was under the control of the Asian monsoon circulation on inter-decadal to centennial timescales in the past centuries. Copyright © 2010 Royal Meteorological Society

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