Isotopic composition of precipitation over Arid Northwestern China and its implications for the water vapor origin

• Published in: Journal of geographical sciences Vol. 19; no. 2; pp. 164 - 174
• Main Authors: Liu, Jianrong, Song, Xianfang, Sun, Xiaomin, Yuan, Guofu, Liu, Xin, Wang, Shiqin
• Format: Journal Article
• Language: English
• Published: Heidelberg SP Science in China Press 01.04.2009; Springer Nature B.V
• Subjects: Air temperature; Asia; Atmospheric circulation; Bgi / Prodig; China; Earth and Environmental Science; Evaporation; Fractionation; Geographical Information Systems/Cartography; Geography; Mathematical functions; Meteoric water; Nature Conservation; Physical Geography; Precipitation; Remote Sensing/Photogrammetry; Spatial distribution; Surface temperature; Water reuse; Water vapor; 可视化效果; 同位素组成; 多元线性回归方程; 月降水量; 气候控制; 水汽来源; 西北地区; North-Western China; China; China, People's Rep; precipitation; δ; Arid Northwestern China (ANC); water vapor origin; O; Deuterium; Precipitation; Oxygen 18; Arid area; Model; Isotope analysis; Regression analysis; Water vapor
• ISSN: 1009-637X; 1861-9568
• DOI: 10.1007/s11442-009-0164-3

In order to reveal the characteristics and climatic controls on the stable isotopic composition of precipitation over Arid Northwestern China, eight stations have been selected from Chinese Network of Isotopes in Precipitation （CHNIP）. During the year 2005 and 2006, monthly precipitation samples have been collected and analyzed for the composition of δD and δ^18O. The established local meteoric water line δD=7.42δ^18O＋1.38, based on the 95 obtained monthly composite samples, could be treated as isotopic input function across the region. The deviations of slope and intercept from the Global Meteoric Water Line indicated the specific regional meteorological conditions. The monthly δ^18O values were characterized by a positive correlation with surface air temperature （δ^18O （‰） =0.33 T （℃）-13.12）. The amount effect visualized during summer period （δ^18O （‰） = -0.04P （mm）-3.44） though not appeared at a whole yearly-scale. Spatial distributions of δ^18O have properly portrayed the atmospheric circulation background in each month over Arid Northwestern China. The quantitative simulation of δ^18O, which involved a Rayleigh fractionation and a kinetic fractionation, demonstrated that the latter one was the dominating function of condensation of raindrops. Furthermore, the raindrop suffered a re-evaporation during falling processes, and the precipitation vapor might have been mixed with a quantity of local recycled water vapor. Multiple linear regression equations and a δ^18O-T relation have been gained by using meteorological parameters and δ^18O data to evaluate physical controls on the long-term data. The established δ^18OT relation, which has been based on the present-day precipitation, could be considered as a first step of quantitatively reconstructing the historical environmental climate.