【摘要】 蒸发是水循环的一个重要环节，探究河水蒸发比例变化特征有利于流域水资源管理。通过分析天山乌鲁木齐河中上游夏季（6～8月）河水理化指标及同位素组成特征，运用瑞利分馏模型，探讨氢氧稳定同位素对河水蒸发的指示作用。结果表明：1)夏季河水同位素组成呈现出显著的月际差异和空间分异特征，夏季中上游河水δ²H和δ¹⁸O值变化范围分别为-83.7‰～-41.6‰和-15.64‰～-6.70‰。6月和7月同位素组成较8月更富集，上游河段同位素组成的波动幅度大于中游河段。2)河水同位素组成与水体理化性质存在显著相关性。6月，河水的δ²H和δ¹⁸O值与电导率呈显著正相关（P<0.05）;7月，δ²H值与pH值、水温和电导率呈显著负相关（P<0.05）;8月，δ²H和δ¹⁸O值与pH值、水温和电导率呈负相关（P<0.05）,与海拔呈正相关（P<0.01）。3)乌鲁木齐河夏季中上游河水蒸发比例呈现显著的月际差异，基于δ²H和δ¹⁸O量化的结果显示：6月蒸发比例分别为23.6%～31.3%和28.2%～35.7%,7月增至26.9%～35.7%和29.6%～42.3%,而8月则降至14.5%～22.7%和24.5%～29.0%,7月蒸发强度最大，6月次之，8月最弱。统计分析揭示蒸发比例与高程、pH值、电导率和NDWI均呈显著相关（P<0.05）。4)基于后向轨迹模型模拟得出夏季河水的水汽主要源自大西洋水汽，其次为天山山脉和印度洋水汽。文中研究首次量化了乌鲁木齐河水体蒸发比例，研究成果可服务于乌鲁木齐河流域水资源精细化管理，对加深干旱区气候变化条件下水文过程的认识具有重要意义。更多还原

【Abstract】 Evaporation is a crucial component of the water cycle, so investigating the variation characteristics of river water evaporation ratios is beneficial for watershed water resource management. By analyzing the physicochemical indicators and isotopic composition of the water in the middle and upper reaches of the Urumqi River in the Tianshan Mountains during the summer（June to August）, and employing the Rayleigh fractionation model, this study explores the indicative role of stable hydrogen and oxygen isotopes in river water evaporation.The results indicate that: 1)The river water isotopes exhibited significant monthly variations and spatial heterogeneity. The δ²H and δ¹⁸O values in the middle and upper reaches ranged from-83.7‰ to-41.6‰ and-15.64‰ to-6.70‰, respectively. Isotopic compositions were more enriched in June and July than in August, with greater fluctuation amplitudes observed in the upstream river segments than in the midstream segments. 2) The isotopic composition of river water showed significant correlations with the physico-chemical properties of the water. In June, δ²H and δ¹⁸O values of the river water were significantly positively correlated with electrical conductivity（P<0.05）. In July, δ²H values exhibited significant negative correlations with pH, water temperature, and electrical conductivity（P<0.05）. In August, both δ²H and δ¹⁸O values were negatively correlated with pH, water temperature, and electrical conductivity（P<0.05）, while being positively correlated with altitude（P<0.01）. 3) The evaporation proportion of river water in the mid-upper reaches of the Urumqi River during the summer exhibited significant monthly variations. Quantification based on δ²H and δ¹⁸O results showed that the evaporation proportions were 23.6%～31.3% and 28.2%～35.7% in June, increasing to 26.9%～35.7% and 29.6%～42.3% in July, and then decreasing to 14.5%～22.7% and 24.5%～29.0% in August. The evaporation intensity was the highest in July, followed by June, and the lowest in August. Statistical analysis revealed that the evaporation proportion was significantly correlated with altitude, pH, electrical conductivity, and the Normalized Difference Water Index（NDWI）（P<0.05）. 4) Backward trajectory modeling revealed that summer river moisture was primarily derived from Atlantic sources, with secondary contributions from the Tianshan Mountains and Indian Ocean. This study represents the first quantitative assessment of evaporation proportions in the Urumqi River, providing critical data to support precision water resource management in the basin. These findings significantly advance our understanding of hydrological processes in arid regions under climate change situations.更多还原