Climatic significance of tree-ring δ

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• 作者：Xiaohong Liu ; Xuemei Shao ; Eryuan Liang ; Tuo Chen ; Dahe Qin ; Wenling An ; Guobao Xu ; Weizhen Sun ; Yu Wang
• 关键词：Oxygen isotopes ; Tree rings ; Temperature effects ; Atmospheric circulation patterns
• 刊名：Chemical Geology
• 出版年：2009
• 出版时间：20 October 2009
• 年：2009
• 卷：268
• 期：1-2
• 页码：147-154
• 全文大小：1156 K

文摘

It is important to understand the history and dynamics of climate in a transitional region between areas with different atmospheric circulation patterns, where the vegetation and ecosystems are vulnerable to environmental change. We investigated variations in the long-term oxygen isotope composition (δ¹⁸O) in tree rings of Qinghai spruce (Picea crassifolia) and their relationships to climatic parameters in the arid Qilian Mountains of northwestern China from 1870 to 2006. We found that the mean temperature from the previous November to the current February was significantly and positively correlated with the tree-ring δ¹⁸O values. The temperature effect, (the positive relationship between the temperature and the precipitation δ¹⁸O value) can explain the connection between temperature and the tree-ring δ¹⁸O values. Due to pooling of the earlywood and latewood into yearly tree-ring samples, it appears that the cellulose δ¹⁸O may be influenced by isotopically nonhomogeneous water sources and climatic conditions during the previous and current growing seasons. Subtle shifts and amplitude deviations in cellulose δ¹⁸O, which abruptly became more positive around 1977–1978, may be attributed to the shifting climatic regime in China and to temperature variations, respectively. Our results illustrated the potential for investigating climatic or atmospheric circulation patterns based on oxygen isotope records in tree rings in regions near the interface between different large-scale synoptic circulations.