%A ZongXing Li, Qi Feng, YaMin Wang, JianGuo Li, XiaoYan Guo, YongGe Li %T Effect of sub-cloud evaporation on the δ18O of precipitation in Qilian Mountains and Hexi Corridor, China %0 Journal Article %D 2016 %J Sciences in Cold and Arid Regions %R 10.3724/SP.J.1226.2016.00378 %P 378-387 %V 8 %N 5 %U {http://www.scar.ac.cn/CN/abstract/article_128.shtml} %8 2016-10-01 %X The sub-cloud evaporation effect refers to the evaporation process for raindrops that fall from the cloud base to the ground, which is usually accompanied by depleted light isotopes and enriched heavy isotopes in the precipitation. Based on 461 event-based precipitation samples collected from 12 weather stations in the Qilian Mountains and the Hexi Corridor from May to August of 2013, our results indicated that sub-cloud evaporation has a great influence on the δ18O of precipitation, especially in small-amount precipitation events. In May, June, July, and August the δ18O composition was enriched by 35%, 26%, 39%, and 41%, respectively, from the cloud base to the ground. This influence clearly strengthened with temperature rise, from the Qilian Mountains to the Hexi Corridor. When falling raindrops are evaporated by 1.0% in the Qilian Mountains and the Hexi Corridor, the composition of δ18O would be enriched by 1.2% and 2.6%, respectively. Temperature dominated the sub-cloud evaporation in the Qilian Mountains, whereas relative humidity controlled it in the Hexi Corridor. These results provide new proofs of the evolutional process of stable isotopes in precipitation in arid regions.