Stable oxygen isotope differences between the areas to the north and south of Qinling Mountains in China reveal different moisture sources

Yu, Wusheng, Yao, Tandong, Lewis, Stephen, Tian, Lide, Ma, Yaoming, Xu, Baiqing, and Qu, Dongmei (2014) Stable oxygen isotope differences between the areas to the north and south of Qinling Mountains in China reveal different moisture sources. International Journal of Climatology, 34 (6). pp. 1760-1772.

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Abstract

δ18O variability in daily precipitation at two stations (Lanzhou and Zhangye) north of the Qinling Mountains at the eastern margin of the Tibetan Plateau, China, and monthly precipitation δ18O at four stations to the south of the Qinling Mountains were examined. The data show that the δ18O composition of precipitation south of the Qinling Mountains is influenced strongly by the prevailing westerlies during winter and by the summer Asian monsoon during its most active periods. To the north, the westerlies prevail in winter, and δ18O trends coincide strongly with temperature. In summer, the Qinling Mountains block or weaken the Asian monsoon, which crosses them only during the most active periods. In these periods, the stations to the north experience relatively depleted δ18O values (<−7‰). During weak monsoon periods, however, most of the δ18O values in summer precipitation at Lanzhou and Zhangye are relatively enriched (>−5‰, and even as high as +9.2‰). A positive northward weighted average δ18O gradient of summer precipitation with increasing distance from the coast suggests the influence of the prevailing westerlies and of continental recycling of moisture. Both the frequency of these heavily depleted δ18O values and their duration decrease from south to north, reaching minimums at Zhangye, which may have been in the monsoonal tail region during the sampling period. The data reveal that the Qinling Mountains act as an important climatic divide along the eastern margin of the Tibetan Plateau. The effects of the Asian summer monsoon and of different moisture sources should be considered for paleoclimatic studies.

Item ID: 32243
Item Type: Article (Refereed Research - C1)
Keywords: Qinling Mountains; precipitation; δ18O; moisture sources; Asian summer monsoon
ISSN: 1097-0088
Funders: National Science Foundation of China (NSFC), Chinese Academy of Sciences (CAS), National Basic Research Program of China
Projects and Grants: NSFC 41190081, NSFC 41025002, NSFC 41125003, NSFC 40830638, NSFC 40971049, CAS XDB03030207, National Basic Research Program of China 2010CB954702
Date Deposited: 12 Jun 2014 03:15
FoR Codes: 04 EARTH SCIENCES > 0402 Geochemistry > 040203 Isotope Geochemistry @ 100%
SEO Codes: 96 ENVIRONMENT > 9603 Climate and Climate Change > 960301 Climate Change Adaptation Measures @ 100%
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