A 210-year tree-ring δ¹⁸O record in North China and its relationship with large-scale circulations

Abstract

Tree-ring stable oxygen isotope (δ¹⁸O_TR) demonstrates the enormous potential for revealing hydrological climate changes and large-scale atmospheric circulations. Here, we established the 210-year δ¹⁸O_TR chronology of Pinus tabulaeformis Carr. in Baotou, southwest Inner Mongolia, North China. The regional precipitation δ¹⁸O (δ¹⁸O_P) and June-July-August relative humidity (RH_JJA) were the two dominant environmental factors controlling the δ¹⁸O_TR changes. Since the 1930s, the increasing δ¹⁸O_TR values ​in the study region reflected the drying trend due to reducing precipitation and increasing temperature. The δ¹⁸O_TR series in Baotou generally exhibited stronger correlations with three Indian summer monsoon (ISM) indexes than three East Asian summer monsoon (EASM) indexes during 1948–2009 AD. However, the δ¹⁸O_TR record also significantly correlated with one EASM index. These results indicated that the Asian summer monsoon played an essential role in modifying the δ¹⁸O_TR values, and the ISM possibly had more considerable influence compared with the EASM. We also found that the δ¹⁸O_TR record had a higher correlation with the central-Pacific El Niño-Southern Oscillation (ENSO) than that with eastern-Pacific ENSO, probably because of the more substantial impact of the central-Pacific ENSO on the ISM.

Keywords:

• tree ring
• stable oxygen isotope (δ18O)
• Asian monsoon
• El Niño-Southern Oscillation (ENSO)
• climate change

Acknowledgement

We thank two anonymous reviewers for their helpful comments and suggestions.

Declaration of interest

No potential conflict of interest was reported by the authors.

Data availability statement

Data that have contributed to the reported results are available from the corresponding author on request.

Additional information

Funding

This work was supported by Chinese Academy of Sciences (CAS) under Grant QYZDJ–SSW–DQC021, DQGG0104, GJHZ1777, XDA23070202; Youth Innovation Promotion Association of CAS under Grant No. 2017451; National Natural Science Foundation of China under Grant NSFC 41630531; West Light Foundation from CAS; the Key Project of IEECAS; and the project of the State Key Laboratory of Loess and Quaternary Geology, IEECAS under Grant SKLLQG1822.