The Partitioning of Catchment Evapotranspiration Fluxes as Revealed by Stable Isotope Signals in the Alpine Inland River Basin

Evapotranspiration is an important process in the water budget of an ecosystem. Quantifying the components of evapotranspiration is of great significance in revealing the ecohydrological process of alpine inland river basins. In this study, the evapotranspiration fluxes in the Shaliu River basin were classified by hydrogen and oxygen stable isotope technology and remote sensing technology. The results showed the following: (1) The average value of soil fractional evaporation (E-1) in the summer of 2018 and 2019 was 7.59 mm and 2.10 mm, respectively. (2) The average ratio of soil evaporation (E-soil) in the summer of 2018 was 48.82%, 68.11%, 54.99%, respectively. The average ratio of E-soil in the summer of 2019 was 66.86%, 57.50%, 55.53%, respectively. The average value of E-soil in the summer of 2018 and 2019 was 42.84 mm and 35.36 mm, respectively. (3) The average ratio of vegetation transpiration (T) in the summer of 2018 was 51.18%, 31.89%, and 45.01%, respectively. The average ratio of T in the summer of 2019 was 33.14%, 42.50%, and 44.47%, respectively. The average value of T in the summer of 2018 and 2019 was 32.59 mm and 26.23 mm, respectively. Obviously, the soil fractionation was stronger in the summer of 2018 than that in the summer of 2019. At the same time, both soil evaporation and plant transpiration in summer 2018 were higher than those in summer 2019, and soil evaporation in the Shaliu River basin was greater than plant transpiration in summer during the study period. The results of this study can provide data reference for mastering the eco-hydrological process of the Shaliu River basin.

Automated summary

Evapotranspiration is an important process in the water budget of an ecosystem. This study used hydrogen and oxygen stable isotope technology and remote sensing technology to classify evapotranspiration fluxes in the Shaliu River basin. The results showed that soil fractionation was stronger in the summer of 2018 compared to 2019, and both soil evaporation and plant transpiration in summer 2018 were higher than those in summer 2019. Soil evaporation in the basin was greater than plant transpiration during the study period. This study provides data reference for understanding the eco-hydrological process of the Shaliu River basin.