布哈河流域丰水期降水及河水氢氧同位素研究OA

In this study,we analyzed the temporal and spatial variation of stable isotopes and deuterium surplus(D-excess)in river water and precipitation in the Buha River basin,clarified the atmospheric pre-cipitation line and river water line during the wet season,and discussed the relationship between precipita-tion stable isotopes and temperature and precipitation.We also tracked the water vapor source of precipita-tion in the basin by running the model backwards.The aim of the study was to explore the moisture sourc-es of the Buha River basin,eco-hydrological cycling and offer scientific insights for source attribution and support for ecological cycle studies in the region.The study was based on the precipitation and river water isotope data as well as meteorological data for the wet season(May-September)of 2023 in the Buha Riv-er basin.Results show that:(1)The δ2H and δ18O variation ranges of river water during the wet season in the Buha River basin were-59.12--38.81‰and-13.74--8.9‰,respectively.Spatially,stable isotope val-ues in river water exhibited depletion in the northwest and enrichment in the southeast.The δ2H and δ18O ranges of precipitation were-127.7--0.58‰ and-21.37--6.33％o,respectively,a broader range than for river water.Both precipitation and river water showed generally elevated d-excess values.(2)The slope and intercept of the atmospheric precipitation line during the wet season of the basin were significantly higher than those of the global atmospheric precipitation line,while the slope and intercept of the river water line were lower than those of the local atmospheric precipitation line,indicating that the river water underwent intense evaporation.(3)The precipitation stable isotope values did not show significant temper-ature or rainfall effect and,while the stable isotope values of river water decreased with increasing alti-tude,the effect was not significant.(4)Simulation results from the backwards trajectory model showed that the primary source of water vapor for precipitation during the wet season was the Atlantic Ocean,transported to the basin by the westerly winds.