Stable isotopes applied as water tracers for infiltration experiment  

作　　者：LIU Xiaoyan CHEN Jiansheng SUN Xiaoxu SU Zhiguo 

机构地区：[1]State Key Laboratory of Hydrology, Water Resources & Hydraulic Engineering Hohai University, Nanjing 210098, China [2]College of Earth Sciences and Engineering, Hohai University, Nanjing 210098, China

出　　处：《Nuclear Science and Techniques》2011年第4期251-256,共6页核技术（英文）

基　　金：Supported by the National University Foundation of China (Grant No.50809024);the National Natural Science Foundation of China (Grant No 40973001)

摘　　要：The δD and δ18O vertical profiles of soil water were measured prior to and after a rainfall event.Mechanisms of soil water movement were deciphered by comparing the soil water isotope profiles with the isotopic composition of precipitation.The results show that evaporation at the upper depth led to enrichment of the heavy isotopes.Compared to the loess profile,the shallow soil water of sand profile is relatively enriched in D and 18O due to macro-pore and low water-holding capacity.The precipitation is infiltrated into soil in piston mode,accompanied with significant mixing of older soil water.The preferential fluid flow in loess was observed at depths of 0-20 cm,caused by cracks in the depths.The hydrogen and oxygen isotopic compositions in outflow are close to the precipitation,which shows a mixing of the precipitation and old soil water,and indicates that the isotopic composition of outflow water is mainly controlled by that of the precipitation.The δD and δ18O in outflow decreased with time until stable δ values of outflow are close to those of the precipitation.The δD and δ18O vertical profiles of soil water were measured prior to and after a rainfall event. Mechanisms of soil water movement were deciphered by comparing the soil water isotope profiles with the isotopic composition of precipitation. The results show that evaporation at the upper depth led to enrichment of the heavy isotopes. Compared to the loess profile, the shallow soil water of sand profile is relatively enriched in D and ^18O due to macro-pore and low water-holding capacity. The precipitation is infiltrated into soil in piston mode, accompanied with significant mixing of older soil water. The preferential fluid flow in loess was observed at depths of 0-20 cm, caused by cracks in the depths. The hydrogen and oxygen isotopic compositions in outflow are close to the precipitation, which shows a mixing of the precipitation and old soil water, and indicates that the isotopic composition of outflow water is mainly controlled by that of the precipitation. The δD and δ18O in outflow decreased with time until stable δ values of outflow are close to those of the precipitation.

关 键 词：土壤水分测定 稳定同位素 渗透实验 同位素组成 应用 示踪 垂直剖面 黄土剖面 

分 类 号：P597.2[天文地球—地球化学] S152.7[天文地球—地质学]