摘要
为分析长江下游小流域不同降雨类型水文要素的同位素特征,结合氢氧同位素资料,分析了长江流域下游和睦桥小流域两场降雨事件(台风雨和梅雨)中各水文要素。结果表明,各水文要素同位素的时程效应较为显著。台风雨事件中降雨同位素愈来愈贫化,而梅雨事件中的降雨同位素具有显著富集趋势。各水体同位素值围绕大气水线分布,表明均由降雨产生。河水同位素变化不明显且分布最为集中,体现了降雨同位素特征的消减性。土壤水同位素由于在土壤水入渗过程中发生了混合作用,造成δ2H-δ18O相关点位于大气水线的右下方且集中分布。研究成果可为长江下游流域的径流成分划分与水循环机理研究提供参考。
In order to study the isotopic characteristics of hydrologic elements for different rainfall types in small watershed of the lower reaches of the Yangtze River,the precipitation,surface water,soil water and river water based on oxygen and hydrogen isotopes were analyzed for two rainfall events(typhoon event and Meiyu rain event)in Hemuqiao catchment,in the lower reaches the of Yangtze River.The results show that the isotope of hydrologic elements exhibited a strong temporal variation.Precipitation isotope in typhoon events had depleted trend contrast with the enrichment characteristics in Meiyu rain event.All the isotopes were distributed around local meteoric water line indicating they were originated from the precipitation.The river isotope had the most concentrated distribution and this result showed the weakness in precipitation isotope.Soil water isotope had a distribution under local meteoric water line because of mixture in soil water infiltration.These results can provide references for study on the runoff generation and water circulation mechanism in the lower Yangtze River basin.
引文
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