Details

Autor(en) / Beteiligte

• Zhu, Xiaofan
• Wu, Tonghua
• Zhao, Lin
• Yang, Chengsong
• Zhang, Huiwen
• Xie, Changwei
• Li, Ren
• Wang, Weihua
• Hu, Guojie
• Ni, Jie
• Du, Yizhen
• Yang, Shuhua
• Zhang, Yuxin
• Hao, Junming
• Yang, Cheng
• Qiao, Yongping
• Shi, Jianzong

Titel

Exploring the contribution of precipitation to water within the active layer during the thawing period in the permafrost regions of central Qinghai-Tibet Plateau by stable isotopic tracing

Ist Teil von

• The Science of the total environment, 2019-04, Vol.661, p.630-644

Ort / Verlag

Netherlands: Elsevier B.V

Erscheinungsjahr

2019

Link zum Volltext

Quelle

Elsevier ScienceDirect Journals

Beschreibungen/Notizen

• Stable isotopic tracing has proven to be a useful tool for assessing surface water source dynamics and hydrological connectivity in permafrost regions. This study has investigated the contribution of precipitation to water within the active layer at three long-term observation sites, including Fenghuoshan (FHS), Hoh Xil (KKXL) and Wudaoliang (WDL), by using isotopic tracer technique and two-component mixing model. The results showed that precipitation was the predominant source for water within the active layer, permafrost and ground ice near permafrost table at the three sites. Precipitation in August was the predominant source for water within the active layer at FHS, and precipitation in September was the main source at KKXL and WDL. The variation of isotopic values at different levels indicated that the water sources within the active layer could vary as the depth increases. The evaporation fractionation of water within the active layer at WDL was noticeable at depths of 0–50 cm, and the evaporation intensity decrease gradually from late June to late September. The relationship of isotopic tracing values between precipitation and water within the active layer at depths of 0–50 cm becomes more significant as the amount of the recently-occurring precipitation increases. Moreover, the relatively higher d-excess in precipitation indicates that local recycled moisture has greater contribution to precipitation. The differences of d-excess in most water within the active layer, permafrost and ground ice near permafrost table revealed that there were isotopic fractionation when precipitation supplying to above-mentioned three water bodies. The precipitation event amounted to 8.1 mm at KKXL can exert 49% ± 7.1% and 30.8% ± 3.6% contribution to water within the active layer at depths of 0–10 cm and 10–20 cm, respectively. While the long-period contribution cannot be identified because of the impact of evaporation. The results would provide new insights into the contribution of precipitation to water within the active layer on the QTP, which is also helpful to improve process-based hydrological models in the permafrost regions. [Display omitted] •Precipitation is the predominant source for water within the active layer.•Obvious evaporation fractionation sign for water within the active layer exists at depths of 0–50 cm.•The contribution ratio of single precipitation event to water within the active layer can be identified.