TY - JOUR
T1 - Increased drought events in southwest China revealed by tree ring oxygen isotopes and potential role of Indian Ocean Dipole
AU - Xu, Chenxi
AU - An, Wenling
AU - Wang, S. Y.Simon
AU - Yi, Liang
AU - Ge, Junyi
AU - Nakatsuka, Takeshi
AU - Sano, Masaki
AU - Guo, Zhengtang
N1 - Funding Information:
We deeply appreciate the helpful comments from two anonymous reviewers and editor to improve the manuscript. The project was supported by Natural Science Foundation of China (Grant No. 41672179 , 41672352 , 41630529 , 41430531 , 41690114 , 41888101 ), the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB26020000 , XDA13010106 ), the Chinese Academy of Sciences (CAS) Pioneer Hundred Talents Program, the National Key R&D Program of China (Grant No. 2016YFA0600502 , 2017YFE0112800 ). No potential conflict of interest was reported by the authors.
Publisher Copyright:
© 2019 Elsevier B.V.
PY - 2019/4/15
Y1 - 2019/4/15
N2 - The highlands in southwestern China experience pronounced fluctuations in the hydroclimate with profound impacts on agriculture and economics. To investigate the drought history of this region beyond instrumental records, a tree ring cellulose oxygen isotope (δ 18 O c ) chronology was developed for the period 1733–2013 using samples collected from six Larix trees in the low-latitude highlands (LLH) of southwestern China. The analysis revealed that δ 18 O c is significantly correlated with the rainy season (May–October) precipitation and relative humidity, as well as drought severity. The δ 18 O c chronology accounts for 46% of the observed variance in the rainy season precipitation and it was subsequently used to reconstruct precipitation. The reconstructed precipitation reveals an apparent drying trend since 1840, accompanied by increasingly frequent drought events since 1970. Interdecadal variability is also present, characterized with two distinct wet periods in 1740–1760 and 1800–1900 and two drier periods in 1760–1800 and 1900–2013. On the interannual timescale, the LLH precipitation was modulated collectively by the El Niño–Southern Oscillation (ENSO) and the Indian Ocean dipole (IOD). There appears to be an enhanced precipitation-IOD relationship since 1970 in response to the increase in positive-IOD events, implying an increasing likelihood of drought for the southwest China LLH.
AB - The highlands in southwestern China experience pronounced fluctuations in the hydroclimate with profound impacts on agriculture and economics. To investigate the drought history of this region beyond instrumental records, a tree ring cellulose oxygen isotope (δ 18 O c ) chronology was developed for the period 1733–2013 using samples collected from six Larix trees in the low-latitude highlands (LLH) of southwestern China. The analysis revealed that δ 18 O c is significantly correlated with the rainy season (May–October) precipitation and relative humidity, as well as drought severity. The δ 18 O c chronology accounts for 46% of the observed variance in the rainy season precipitation and it was subsequently used to reconstruct precipitation. The reconstructed precipitation reveals an apparent drying trend since 1840, accompanied by increasingly frequent drought events since 1970. Interdecadal variability is also present, characterized with two distinct wet periods in 1740–1760 and 1800–1900 and two drier periods in 1760–1800 and 1900–2013. On the interannual timescale, the LLH precipitation was modulated collectively by the El Niño–Southern Oscillation (ENSO) and the Indian Ocean dipole (IOD). There appears to be an enhanced precipitation-IOD relationship since 1970 in response to the increase in positive-IOD events, implying an increasing likelihood of drought for the southwest China LLH.
KW - Indian Ocean Dipole
KW - Precipitation
KW - Southwest China
KW - Tree ring oxygen isotope
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U2 - 10.1016/j.scitotenv.2019.01.186
DO - 10.1016/j.scitotenv.2019.01.186
M3 - Article
C2 - 30682614
AN - SCOPUS:85060306910
VL - 661
SP - 645
EP - 653
JO - Science of the Total Environment
JF - Science of the Total Environment
SN - 0048-9697
ER -