| 黄土丘陵沟壑区小流域不同水体氢氧同位素特征 |
| 摘要点击 2781 全文点击 1091 投稿时间：2018-11-02 修订日期：2019-02-18 |
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| 中文关键词 同位素 转化比例 氘盈余 降水 韭园沟 |
| 英文关键词 isotopes conversion ratio d-escess precipitation Jiuyuangou |
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| 中文摘要 |
| 研究黄土丘陵沟壑区不同水体间同位素特征及水体转化关系，可以更好了解黄土丘陵沟壑区水循环特征，为评价区域环境、气候、生态建设和水资源形成机制提供依据.通过野外采集2017年整年生态建设治理条件良好的韭园沟研究区降水、河水及浅层地下水中δD和δ18O日及月平均数据及相关气象资料，运用稳定同位素技术，分析了不同水体中稳定氢氧同位素的组成关系、影响因子及时空变化，结合二端元混合模型揭示了研究区不同水体中稳定同位素间转化特征.结果显示：河水氘盈余参数在观测期间内呈现出随海拔升高而增大的趋势，河水δ18O值随着距河源距离的增大而富集，随着高度的递增而降低；气温、风速、相对湿度和降水量对大气降水氢氧同位素值均影响显著；河水在非汛期表现为降水和浅层地下水补给河水，比例分别为46%和54%，在汛期为河水和降水补给浅层地下水，比例分别为60%和40%.表明研究区"降水-河水-浅层地下水"间具有良好转化关系，生态建设措施的实施对小流域不同水体转化产生了一定影响.通过以上结果可为流域水资源开发保护及流域生态水文过程研究提供帮助，为建立黄土丘陵沟壑区流域水循环模型提供依据. |
| 英文摘要 |
| Studying the isotope characteristics and water body transformation relationships among different water bodies in the hilly and gully region of the Loess Plateau can provide a theoretical foundation for evaluating regional climate, ecology, and water resources. In this study, daily and monthly averaged δD and δ18O in precipitation, river water, and shallow groundwater were measured in 2017 in the Jiuyuangou watershed, which has a good ecological condition. The compositional relationship between the stable hydrogen and oxygen isotopes in difference water bodies was explored, the influence factors and spatio-temporal variation of δ18O in precipitation and river water were analyzed, and the stable isotope conversion ratios between different water bodies in the study area were calculated using the two-terminal mixed model. The main conclusions of the study are as follows:the d-excess of river water showed an increasing trend with elevation during the observation period; the δ18O of river water was enriched with increasing distance from the river source and decreased with increasing altitude; temperature, wind speed, and relative humidity had significant effects on the hydrogen and oxygen isotopes of precipitation; precipitation and shallow groundwater replenish the river during the non-flood period, the proportions of which were 46% and 54%, respectively; and during the flood season, the shallow groundwater is replenished by river water and precipitation, the proportions were 60% and 40%, respectively. These results indicate that there is a good conversion relationship between "precipitation-river-shallow groundwater" in the study area. The implementation of soil and water conservation measures has had some influence on the conversion of different water bodies in small watersheds. The results provide a basis for the establishment of water cycle models for hilly and gully regions of the Loess Plateau. |
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