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Relationships between the Oxygen Isotopes in East Asian Stalagmites and Large-Scale Atmospheric and Oceanic Modes |
JING Yuan-Yuan1,2, LI Shuanglin1, WAN Jiang-Hua1, LUO Fei-Fei1 |
1Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
2College of Atmospheric Sciences, Chengdu University of Information Technology, Chengdu 610225, China |
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Abstract The stalagmite δ18O record is known to be associated with the climate, but the specifics of the relationship remain unclear. It may not represent variation in air temperature or precipitation, but instead reflect integral changes of monsoon circulation, especially water vapor sources (the so-called “circulation effect”). Since large-scale atmospheric-oceanic modes such as the Atlantic Multidecadal Oscillation (AMO), Pacific Decadal Oscillation (PDO), and North Atlantic Oscillation (NAO) exert significant effects on Asian monsoon, in this paper the authors investigate the relationships of the East Asian stalagmite δ18O record with these modes. The last three centuries form the focus of our study, for which the authors use reconstructed as well as instrumental data. Considering the impacts of human activity, our analysis is conducted with respect to two periods—the pre- and post-industrial periods. The results show significant lead-lag connections: a positive correlation peaks when the PDO leads East Asian stalagmite δ18O by 3 years, which is persistent over the past 300 years; while the relationships of the AMO and NAO with the East Asian stalagmite δ18O record show significant differences in the post-industrial relative to the pre-industrial period. This implies that the East Asian stalagmite δ18O record may primarily reflect the PDO signal.
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Received: 26 May 2014
Revised: 03 June 2014
Accepted: 03 July 2014
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Corresponding Author:
LI Shuanglin
E-mail: shuanglin.li@mail.iap.ac.cn
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