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 

机构地区：[1]School of Earth System Science,Tianjin University,Tianjin 300072,China [2]College of Forestry,Gansu Agricultural University,Lanzhou 730070,Gansu Province,China [3]Key Laboratory of Biosafety,Nanjing Institute of Environmental Sciences,Ministry of Ecology and Environment,Nanjing 210042,Jiangsu,China

出　　处：《Acta Geochimica》2021年第2期176-183,共8页地球化学学报（英文）

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)。

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.

关 键 词：Water stable isotopes Mountain watersheds Water evaporation losses Altitude effect Rayleigh fractionation 

分 类 号：P333[天文地球—水文科学]