Stalagmite oxygen isotope (δ18O) record has been widely used in characterizing Asian Monsoon variations. In southwest (SW) China, although the stalagmite δ18O was usually suggested as a precipitation proxy, it remains a subject of debate. Here we present two replicated, high-precise-dated stalagmite δ18O records for the interval 1710–2003 AD from Yunnan province, SW China. The stalagmite δ18O shows no correlation with the local monsoon precipitation, but a significantly positive correlation with the Pacific Decadal Oscillation (PDO) index. It demonstrates that the stalagmite δ18O in SW China is most likely influenced by the atmospheric circulation associated with the PDO through the upstream depletion mechanism. During the warm (cold) PDO period, the deficit rainfall over India would make the δ18O of water vapor transporting to SW China less (more) negative due to the weaker Rayleigh distillation process, which would lead to the less (more) negative stalagmite δ18O. Consequently, the stalagmite δ18O in SW China is suitable to reconstruct the PDO variations. It is important to note that the other factors, such as El Niño–Southern Oscillation (ENSO) or sea surface temperature (SST) also possibly affect the stalagmite δ18O in SW China, and the relationship between them requires further studies.
Bibliographical noteFunding Information:
We deeply appreciate the helpful comments from two anonymous reviewers and editor to improve the manuscript. We are grateful to PhD Qian Xu (University of Hong Kong) and PhD Miaofa Li (Fujian Normal University) for their helpful discussions, and thank Wenling An (Institute of Geology and Geophysics, Chinese Academy of Sciences) for sharing her tree-ring δ 18 O data. This research was supported by the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB26020000 ), the National Key Research and Development Program of China ( 2017YFA0603401 ), National Natural Science Foundation of China (Grant No. 41772184 , 41731174 and 41888101 ) and the U.S. NSF (Grant No. 1702816). Data archiving is underway and the datasets will be uploaded to https://www.ncdc.noaa.gov/dataaccess/paleoclimatology-data/datasets/speleothem .
© 2021 Elsevier Ltd
- Oxygen isotope
- Pacific decadal oscillation
- Southwest China
- Upstream depletion