Details

Autor(en) / Beteiligte

• Wang, Liheng
• Liu, Wenjing
• Xu, Zhifang
• Zhang, Jiangyi

Titel

Water sources and recharge mechanisms of the Yarlung Zangbo River in the Tibetan Plateau: Constraints from hydrogen and oxygen stable isotopes

Ist Teil von

• Journal of hydrology (Amsterdam), 2022-11, Vol.614, p.128585, Article 128585

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2022

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• •The isotopic composition of stream water is controlled by the different sources.•The lapse rate of δ18O was −0.19 ‰/100 m across the YZR Basin.•Potential sources of YZR were identified and quantified. Investigations of the hydrological processes of the Yarlung Zangbo River (YZR), a sizeable highland river on the southern margin of the Tibetan Plateau (TP), face challenging constraints owing to the complexities in the water sources and cycle pathway. A total of 156 stream water samples from the YZR Basin were collected and analyzed to elucidate our understanding of regional hydroclimate. The isotopic values were more negative in the uppermost reaches of the YZR and progressively increased along the river, with mean δ18O and δD values at − 15.16 ‰ and − 111.58 ‰, respectively. A clear negative gradient of − 0.19 ‰/100 m was obtained from the datasets, which is consistent with that of the southeastern TP. The linear regression for all samples was δD = 8.64 × δ18O + 19.80 (R2 = 0.93, n = 192), and the slope and intercept were highly similar to those of the meteoric water line in the TP, suggesting that precipitation plays a dominant role in stream recharge sources. Combining the results from the air mass trajectory model and the d-excess values, we found that moisture in the YZR originates mainly from the Bay of Bengal, with westerly mixing in the upper reaches. In addition to precipitation, glacial meltwater and geothermal waters were considered significant water sources for the YZR based on geographic and geological conditions. The proportion of glacial meltwater in the uppermost reaches was calculated to range from 68.2 % to 70.4 % using the end-member mixing analysis method. The contribution ratios of precipitation, glacial meltwater, and geothermal water were almost equal in the middle of the basin, while glacial meltwater contribution dominated in the downstream regions. These findings will significantly impact understanding of the hydrological cycle in the study area and provide vital baseline knowledge about the contribution proportion of different recharge sources in the YZR basin.