Environmental effect and spatiotemporal pattern of stable isotopes in precipitation on the transition zone between the Tibetan Plateau and arid region

Gui Juan; Zongxing Li; Feng Qi; Yuan Ruifeng; Ning Tingting; Zhang Baijuan; Xue Jian; Gao Wende; Nan Fusen; Ding Weixuan; Yang Anle; Liang Pengfei

doi:10.1016/j.scitotenv.2020.141559

Environmental effect and spatiotemporal pattern of stable isotopes in precipitation on the transition zone between the Tibetan Plateau and arid region

Sci Total Environ. 2020 Dec 20:749:141559. doi: 10.1016/j.scitotenv.2020.141559. Epub 2020 Aug 12.

Authors

Gui Juan¹, Zongxing Li², Feng Qi³, Yuan Ruifeng³, Ning Tingting³, Zhang Baijuan³, Xue Jian³, Gao Wende³, Nan Fusen³, Ding Weixuan³, Yang Anle³, Liang Pengfei³

Affiliations

¹ Observation and Research Station of Eco-Hydrology and National Park by Stable Isotope Tracing in Tibetan Plateau/Key Laboratory of Ecohydrology of Inland River Basin/Gansu Qilian Mountains Eco-Environment Research Center, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China.
² Observation and Research Station of Eco-Hydrology and National Park by Stable Isotope Tracing in Tibetan Plateau/Key Laboratory of Ecohydrology of Inland River Basin/Gansu Qilian Mountains Eco-Environment Research Center, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China. Electronic address: lizxhhs@163.com.
³ Observation and Research Station of Eco-Hydrology and National Park by Stable Isotope Tracing in Tibetan Plateau/Key Laboratory of Ecohydrology of Inland River Basin/Gansu Qilian Mountains Eco-Environment Research Center, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.

PMID: 33370891
DOI: 10.1016/j.scitotenv.2020.141559

Abstract

In the transition zone between the Tibetan Plateau and the arid region of northwestern China, the spatiotemporal patterns and environmental controls of stable isotopes in precipitation remain unclear. A network of 19 sampling stations was established across the Qilian Mountains to observe stable isotopes in precipitation, and 1310 precipitation event-scale samples were collected. The local meteoric water line (LMWL) was obtained and expressed as δD = 7.99δ¹⁸O + 14.57 (R² = 0.96). The spatiotemporal patterns of the stable isotopes were mainly dominated by the co-influence of the water vapor sources and the local environment. The westerly circulation, monsoon circulation, and Arctic circulation accounted for 79%, 13%, and 8% of all precipitation events in the study region, respectively. The rainout process also caused oxygen isotope depletion for continuous precipitation events. When the temperature increased by 1 °C, δ¹⁸O increased by 0.47‰, but this increase varied with the temperature range. The effect of precipitation amount was apparent in summer and was caused by sub-cloud evaporation. In addition, δ¹⁸O decreased by 0.13‰ for every 100 m increase in altitude in the Qilian Mountains. Future research should focus on quantifying the co-influence of sub-cloud evaporation, local moisture recycling, and water vapor sources on stable isotopes in precipitation.

Keywords: Environmental effect; Local environment; Qilian Mountains; Spatiotemporal pattern; Water vapor sources.