| 黑河上游高寒山区降雨-径流形成过程的同位素示踪 |
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| 引用本文： | 潘钊,孙自永,马瑞,常启昕,胡雅璐,刘源,王旭.黑河上游高寒山区降雨-径流形成过程的同位素示踪[J].地球科学,2018,43(11):4226-4236. |
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| 作者姓名： | 潘钊 孙自永 马瑞 常启昕 胡雅璐 刘源 王旭 |
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| 作者单位： | 1.中国地质大学环境学院, 湖北武汉 430074 |
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| 基金项目： | 国家重点研发计划课题2017YFC0406105国家自然科学基金项目4141070国家自然科学基金项目91325101国家自然科学基金项目91125009 |
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| 摘 要： | 为揭示中、低纬度高寒山区降雨-径流的形成过程，指导水资源的合理开发利用，选择黑河上游红泥沟小流域为研究区，基于河道径流量及雨水和河水稳定同位素的观测数据，构建二元混合模型，计算了2013年7月23日及8月21日两次典型降雨-径流事件中事件水（降雨）和事件前水（流域前期储水）对河道径流的贡献及其动态变化.结果显示:两次降雨事件中事件前水的贡献比例分别为68.69%和54.46%；事件前水的贡献比例在涨水阶段减小，在退水阶段增大.结合河水电导率的观测结果，进一步分析了降雨-径流的形成过程:河道径流的形成主要受饱和区蓄满产流、河岸带地下径流和山坡地下径流3种产流机制控制；事件水主要源于蓄满产流，事件前水主要源于河岸带和山坡地下径流；事件初期和末期以河岸带地下水补给为主，涨水阶段后期和退水阶段前期转为以蓄满产流和山坡地下水补给为主，洪峰期间蓄满产流的贡献达到最大.两次事件的对比表明，事件前的湿度条件和降雨强度对降雨-径流的形成过程有着重要影响:前期越湿润，流域储水能力越弱，导水能力越强，事件水的贡献越大，河道径流对降雨的响应越迅速；降雨强度越大，蓄满产流及其中的事件水比例越高，河道径流中事件水的比例也越高.
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| 关 键 词： | 高寒山区 径流分割 稳定同位素 水分来源 电导率 地下水 |
| 收稿时间： | 2017-12-07 |
Isotopic Investigation of Rainfall-Runoff Generation in an Alpine Catchment in Headwater Regions of Heihe River,Northeast Qinghai-Tibet Plateau |
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| Abstract: | The objective of this study is to identify the dominant rainfall-runoff generation mechanisms in the middle-low latitude alpine catchment, which can guide the exploitation and utilization of water resources, stream discharge and isotopic composition of rainwater and stream water in the Hongnigou catchment, an alpine catchment in the headwater regions of the Heihe River, Northeast Qinghai-Tibet plateau, were determined during two typical rainfall-runoff events on July 23 and August 21, 2013. Two-component hydrograph separation along with δ2H of rainwater and stream water was used to estimate the contributions of event and pre-event waters to streamflow and their variations over time. The results show that storm runoff was dominated by pre-event water, which contributed 68.69% and 54.46% of the total runoff during the two events, respectively. Pre-event water contributions decreased on rising limbs and increased on recession limbs. The results of the electrical conductivity of stream water suggest that runoff generation at the Hongnigou catchment was controlled by three hydrological processes, namely overland flow from the saturated zone, riparian groundwater, and hillslope groundwater. The majority of event water came from overland flow, whereas pre-event water mainly came from riparian and hillslope groundwaters. At the beginning and ending of the events, riparian groundwater dominated the runoff response while the contributions of overland flow and hillslope groundwater were limited. During the other parts of the events, i.e., from the late rising limb to early recession limb, overland flow and hillslope groundwater conversely dominated the runoff response, with the contribution of overland flow reaching its maximum at the streamflow peak. The comparison of event results indicates that event water contributions to streamflow were related to antecedent wetness conditions and rainfall intensity. Event water contribution was larger during the event with higher antecedent moisture condition or with higher rainfall intensity. |
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