干旱区研究

干旱区研究 ›› 2022, Vol. 39 ›› Issue (1): 21-29.doi: 10.13866/j.azr.2022.01.03

• 天气与气候 • 上一篇    下一篇

基于蒸发皿实验的大气水汽氢氧稳定同位素模拟

雷世军1,2(),王圣杰1,2(),朱小凡3,张明军1,2   

  1. 1.西北师范大学地理与环境科学学院,甘肃 兰州 730070
    2.甘肃省绿洲资源环境与可持续发展重点实验室,甘肃 兰州 730070
    3.中国科学院西北生态环境资源研究院,甘肃 兰州 730000
  • 收稿日期:2021-04-19 修回日期:2021-07-26 出版日期:2022-01-15 发布日期:2022-01-24
  • 通讯作者: 王圣杰
  • 作者简介:雷世军（1993-）,男,硕士研究生,主要研究方向为寒旱区生态水文过程. E-mail: geolei@163.com
  • 基金资助:
    国家自然科学基金项目(41971034);国家自然科学基金项目(41701028);甘肃省杰出青年基金项目(20JR10RA112);西北师范大学重大科研项目培育计划项目(NWNU-LKZD2021-04)

Simulation of stable hydrogen and oxygen isotopes in atmospheric water vapor based on an evaporation pan experiment

LEI Shijun1,2(),WANG Shengjie1,2(),ZHU Xiaofan3,ZHANG Mingjun1,2   

  1. 1. College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730070, Gansu, China
    2. Key Laboratory of Resource Environment and Sustainable Development of Oasis, Gansu Province, Lanzhou 730070, Gansu, China
    3. Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, Gansu, China
  • Received:2021-04-19 Revised:2021-07-26 Online:2022-01-15 Published:2022-01-24
  • Contact: Shengjie WANG

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摘要：

大气水汽氢氧稳定同位素直接反映了水在大气中输送、混合和相变等过程的关键信息,通过蒸发皿实验可以模拟大气水汽氢氧稳定同位素组成,但模拟方法的可靠性仍需要实测资料的验证。于2019年9—11月在甘肃兰州进行了蒸发皿实验,对逐日大气水汽氢氧稳定同位素进行模拟,同期利用在线大气水汽氢氧稳定同位素分析仪进行实时监测从而对模拟结果的可靠性进行验证。研究发现：（1） 利用自然蒸发状态下的Craig-Gordon线性阻力模型和水体同位素质量平衡方法模拟得到的大气水汽中δ18O与直接测量得到的大气水汽中δ18O之间表现出较好的一致性,均方根误差为4.5‰,平均绝对误差为3.2‰,平均偏差为0.03‰。（2） 大气水汽中δ18O的模拟残差与相对湿度（R2=0.43）、蒸发剩余比（R2=0.39）和剩余水体同位素值（R2=0.39）都具有一定相关性。（3） 模型对相对湿度的敏感性高,在相对湿度较低时模型误差会增大。在实验末期蒸发剩余比偏低和剩余水体同位素富集的情况下,水汽同位素模拟残差相较于实验前期而言更大。

关键词: 氢氧稳定同位素, 蒸发皿, 模拟, 大气水汽

Abstract:

The stable hydrogen and oxygen isotopes in atmospheric water vapor reflect the key processes of water transport, mixing, and phase change in the atmosphere. The stable isotopic compositions of hydrogen and oxygen in atmospheric water vapor can be simulated using an evaporation pan experiment, but a measurement-based assessment of model reliability is necessary. In this study, an evaporation pan experiment was conducted in Lanzhou, Gansu, from September to November 2019. The daily atmospheric water vapor isotopes were simulated using the Craig-Gordon linear resistance model and the water isotopic mass balance method in a natural evaporative state. Online observations of atmospheric water vapor isotopes were performed using a water vapor isotope analyzer and then the pan-based simulations were verified. The simulated δ 18O in atmospheric water vapor and the directly measured δ 18O were in good agreement with a root mean square error of 4.5‰, a mean absolute error of 3.2‰, and a mean bias error of 0.03‰.The residual of simulated δ18O values were correlated with relative humidity (R2=0.43), remaining ratio (R2=0.39), and the isotopic values of the remaining water bodies (R2=0.39). The model was highly sensitive to relative humidity: lower relative humidity conditionstypically corresponded to a higher error. Under the conditions of low remaining ratio and isotopically enriched remaining water at the end of the evaporation experiment, the simulation residual was much larger than that at the beginning of the experiment.

Key words: stable hydrogen and oxygen isotopes, evaporation pan, simulation, atmospheric water vapor