当前位置: 首页 > 开放交流 > 发表论文

Stable isotope composition of precipitation in the south and north slopes of Wushaoling Mountain, northwestern China

2016-11-29 10:25:43 【 【打印】【关闭】

Stable isotope composition of precipitation in the south and north slopes of Wushaoling Mountain, northwestern China

 

Li Zongxing a,b,, Feng Qi a, Yong Song b, Q.J.Wangb, Jiao Yang c, Li Yongge a, Li Jianguo a, Guo Xiaoyan a

 

a Key Laboratory of Ecohydrology of Inland River Basin/Gansu Hydrology andWater Resources Engineering Research Center, Cold and Arid Region Environment and Engineering Research Institute,Chinese Academy of Sciences, Lanzhou 730000, China

b CSIRO Land and Water, Private Bag 10, Clayton South, VIC 3169, Australia

c Key Laboratory of Meteorological Disaster, Ministry of Education/Institute of Climate Change and Evaluation between China and UK, Nanjing University of Information Science and Technology,Nanjing 210044, China

 

a b s t r a c t

A study of spatial and temporal variability of precipitation isotope composition on the southern and north slopes of Wushaoling Mountain was conducted in order to explore the processes influencing its evolution. The analysis indicated that the isotopic composition, the slopes and intercepts of Local MeteroicWater Lines, altitude gradients and temperature effect are higher on the north slope than those on the south slope. The d-excess showed an increase fromlower to higher altitudes, and the altitude gradients changedwith season. The correlation coefficients between δ18O and d-excess decreased with increasing altitude due to weakening sub-cloud evaporation. Westerly wind principally dominatesWushaoling Mountain, so the relatively negative stable isotope values observed are related to the long distance transportation of water vapor in spring and winter. In summer and autumn, the locally strong sub-cloud evaporation cause relatively higher δ18O and lower d-excess. The results suggested that the sub-cloud evaporation has enriched the δ18O composition by 23%, 23%, 32%, 42% and 29% in May, June, July, August and September, respectively. In some circumstances, δ18O and δD were depleted at the end ofmulti-days rainfall events due to the rainout process. In addition, monsoonal moisture caused some negative δ18O in summer when an enhanced cyclonic circulation had developed on Tibetan Plateau. The study enhances the knowledge of isotopic evolution of precipitation and provides a basis for further study of isotopic hydrology in arid regions.