Estimation of evaporation losses based on stable isotopes of stream water in a mountain watershed

作     者：Zhongcong Sun Chaochen Hu Di Wu Guopeng Chen Xiaoqiang Lu Xueyan Liu Zhongcong Sun;Chaochen Hu;Di Wu;Guopeng Chen;Xiaoqiang Lu;Xueyan Liu

作者机构：School of Earth System ScienceTianjin UniversityTianjin 300072China College of ForestryGansu Agricultural UniversityLanzhou 730070Gansu ProvinceChina Key Laboratory of BiosafetyNanjing Institute of Environmental SciencesMinistry of Ecology and EnvironmentNanjing 210042JiangsuChina 

出 版 物：《Acta Geochimica》 (地球化学学报（英文）)

年 卷 期：2021年第40卷第2期

页      面：176-183页

核心收录：

学科分类：0709[理学-地质学] 0819[工学-矿业工程] 08[工学] 081501[工学-水文学及水资源] 0708[理学-地球物理学] 0815[工学-水利工程] 

基　　金：support by Tanchang County People’s Government,Forestry Bureau of Tanchang County,and Guan’egou National Forest Park on the field work supported by National Natural Science Foundation of China(No.41730855) State Key Project of Research and Development Plan(2016YFA0600802)。 

主　　题：Water stable isotopes Mountain watersheds Water evaporation losses Altitude effect Rayleigh fractionation 

摘      要：Water stable isotopes(δ^(2) H andδ^(18)O)can record surface water evaporation,which is an important hydrological process for understanding watershed structure and function evolution.However,the isotopic estimation of water evaporation losses in the mountain watersheds remains poorly explored,which hinders understanding spatial variations of hydrological processes and their relationships with the temperature and vegetation.Here we investigatedδ^(2) H,δ^(18)O,and d-excess values of stream water along an altitude gradient of 2130 to 3380 m in Guan’egou mountain watershed at the east edge of the Qinghai-Tibet Plateau in China.The meanδ^(2) H(-69.6‰±2.6‰),δ^(18)O(-10.7‰±0.3‰),and dexcess values(16.0‰±1.4‰)of stream water indicate the inland moisture as the major source of precipitation in study area.Water stable isotopes increase linearly with decreasing altitudes,based on which we estimated the fractions of water evaporation losses along with the altitude and their variations in different vegetations.This study provides an isotopic evaluation method of water evaporation status in mountain watersheds,the results are useful for further understanding the relationship between hydrological processes and ecosystem function under the changing climate surrounding the Qinghai-Tibet Plateau.