The major ions in precipitation can reflect the conditions of the atmosphere, while stable isotopic characteristics provide information on the moisture source. In order to understand the local hydro-chemical features and regional geochemical cycle, it is essential to assess the chemical composition of precipitation and the associated sources. Therefore, a total of 57 precipitation samples (2016 to 2017) for major ions and 178 samples (2013 to 2017) for stable isotopes were collected from the Wengguo station and analyzed to explore the major ionic deposition and stable isotopic characteristics in the northern slopes of the Himalayas. The average pH and electrical conductivity were 6.82 ± 0.45 and 15.36 ± 11.67 μS cm−1, respectively. Ca2+ followed by K+ and Mg2+ played a crucial role in neutralizing the precipitation acidity. The major ionic sources in the region were terrigenous (Ca2+, HCO3−, and Mg2+) and sea salt (Na+, Cl−, and Mg2+), as well as anthropogenic emissions (SO42− and NO3−) and biomass burning (K+). The total deposition flux of the major ions was higher in 2016 than in 2017 and was influenced by the higher precipitation. The average values of δ18O and δD in precipitation were − 15.22 ± 5.17 ‰ and − 116.01 ± 41.31 ‰, respectively. The precipitation stable isotopes were not significantly correlated to the local air temperature but the precipitation amount. Moreover, the variation in stable isotopes, local meteoric water line, and d-excess indicated the existence of continental and monsoon moisture transport systems. The transport of chemicals over the high elevation region from polluted cities in South Asia via moisture originating in the Bay of Bengal and the Arabian Sea was determined based on the source identification, clusters of air mass backward trajectory analysis, and the National Center for Environmental Prediction Final dataset. Thus, the ionic concentrations and stable isotopic characteristics of the precipitation from this study provided a valuable dataset to assess the atmospheric environment in the northern slopes of the Himalayas at Southern Tibetan Plateau.

中文翻译：

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喜马拉雅北坡翁果地区降水化学及稳定同位素特征

降水中的主要离子可以反映大气状况，而稳定的同位素特征提供有关水分来源的信息。为了了解当地的水化学特征和区域地球化学循环，必须评估降水的化学成分和相关来源。因此，从文果站采集了57个主要离子降水样本（2016-2017年）和178个稳定同位素样本（2013-2017年），并对其进行了分析，探讨了北坡的主要离子沉积和稳定同位素特征。喜马拉雅山。平均 pH 值和电导率分别为 6.82 ± 0.45 和 15.36 ± 11.67 μS cm-1。Ca2+ 其次是 K+ 和 Mg2+ 在中和沉淀酸度方面起着至关重要的作用。该地区的主要离子源是陆源（Ca2+、HCO3- 和 Mg2+）和海盐（Na+、Cl- 和 Mg2+），以及人为排放（SO42- 和 NO3-）和生物量燃烧（K+）。2016 年主要离子的总沉积通量高于 2017 年，受降水量增加的影响。降水中δ18O和δD的平均值分别为-15.22±5.17‰和-116.01±41.31‰。降水稳定同位素与当地气温的相关性不显着，但与降水量相关。此外，稳定同位素、当地大气水线和 d-excess 的变化表明大陆和季风水分输送系统的存在。化学物质从南亚受污染城市通过源自孟加拉湾和阿拉伯海的水分在高海拔地区的运输是基于源识别、气团反向轨迹分析和国家环境预测中心确定的最终数据集。因此，本研究降水的离子浓度和稳定同位素特征为评估青藏高原南部喜马拉雅山北坡的大气环境提供了有价值的数据集。