干旱区研究

干旱区研究 ›› 2025, Vol. 42 ›› Issue (1): 72-83.doi: 10.13866/j.azr.2025.01.07 cstr: 32277.14.AZR.20250107

• 水土资源 • 上一篇    下一篇

黄河源区典型日近地表土壤-植被-水体蒸散发及水汽同位素特征

柏文文(), 王尚涛(), 倪三川, 贺巨龙, 王春艳, 刘伊丰, 吴淼, 苏宇博, 王凯玉   

  1. 青海大学土木水利学院，黄河上游生态保护与高质量发展实验室，水利部江河源区水生态治理与保护重点实验室，三江源生态与高原农牧业国家重点实验室，青海 西宁 810016
  • 收稿日期:2024-08-12 修回日期:2024-09-29 出版日期:2025-01-15 发布日期:2025-01-17
  • 通讯作者: 王尚涛. E-mail: 2019990024@qhu.edu.cn
  • 作者简介:柏文文（1989-），男，副教授，博士，主要从事水文气象、水力学与河流动力学等方面的研究. E-mail: baiwenwen@qhu.edu.cn
  • 基金资助:
    青海省科技厅青年基金(2023-ZJ-971Q);国家重点研发计划项目(2022YFF1302602);国家自然科学基金(52209092)

Characteristics of near-surface soil-vegetation-water body evapotranspiration and water vapor isotope in typical days in source region of the Yellow River

BAI Wenwen(), WANG Shangtao(), NI Sanchuan, HE Julong, WANG Chunyan, LIU Yifeng, WU Miao, SU Yubo, WANG Kaiyu   

  1. Qinghai University, School of Civil Engineering and Water Resources, Laboratory of Ecological Protection and High-Quality Development in the Upper Yellow River, Key Laboratory of Water Ecology Remediation and Protection at Headwater Regions of Big Rivers, Ministry of Water Resources, State Key Laboratory of Plateau Ecology and Agriculture, Xining 810016, Qinghai, China
  • Received:2024-08-12 Revised:2024-09-29 Published:2025-01-15 Online:2025-01-17

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摘要：

基于蒸发量及其水汽同位素原位观测，研究了黄河源区王家乡典型日近地表土壤-水体-植被蒸散发特性，探讨了土壤-植被-水体蒸散发水汽同位素特征，计算了蒸散发和迁移水汽占比。研究结果表明：土壤、植被蒸散发峰值时间相对于水体蒸发峰值时间存在延迟效应，蒸散发影响土壤水深度为20 cm。不同观测对象（裸土、植被、水体、混合）蒸散发水汽同位素值存在显著性差异，植物散发过程相对土壤蒸发过程，有更加强烈的同位素分馏过程，并且蒸散发消耗土壤水深度越大，分馏效应越强，蒸发引起观测水汽δ18O、δD、δ17O先富集增大后趋于稳定，表明存在同位素平衡分馏过程，而蒸发过程氘盈余持续减小。采用逐小时瑞利分馏模型可以较好的刻画水汽同位素变化特征。水汽同位素端元混合模型计算结果表明观测站点近地表以蒸散发水汽为主，未来在水资源量调配和管理时，应更加关注气候变化对土壤蒸散发量的影响。

关键词: 土壤蒸散发, 水汽同位素, 瑞利分馏模型, 黄河源区

Abstract:

Based on the in situ observation of evaporation and water vapour isotope, the study investigated the characteristics of near-surface soil-water-vegetation evaporation and transpiration in Wangjiaxiang, a typical area in source region of the Yellow River, and explored the isotopic features of water vapour emitted from soil, vegetation, and water bodies. The study also calculated the proportion of evaporation and migrating water vapour. The results show that the peak time of soil and vegetation evaporation is delayed relative to the peak time of water body evaporation, and the influence of evaporation on soil water depth is 20 cm. There are significant differences in the isotopic values of evaporation between different observation objects (bare soil, vegetation, water bodies, and mixed), the isotope fractionation process during plant transpiration is generally stronger than that during soil evaporation. The isotopic fractionation effect becomes stronger as the depth of soil water consumed by evaporation increases. Evaporation causes the observed water vapour δ18O, δD and δ17O to initially enrich and then stabilize, indicating the existence of an isotopic equilibrium process, while the d-excess continues to decrease during evaporation. The hourly Rayleigh fractionation model can reflect the changes in the isotopic composition of evaporation water vapour to a good extent. The results of the endmember mixing model for water vapour isotopes show that the near-surface observation site, water vapour is mainly dominated by evapotranspirationn. Future water resource allocation and management should pay more attention to the impact of climate change on soil evaporation.

Key words: soil evapotranspiration, water vapour isotopes, Rayleigh fractionation model, source region of the Yellow River