洮儿河流域径流事件对降水的响应研究

以洮儿河流域为研究对象，选取洮南水文站1960—2016年日径流数据，采用改进退水系数后的Chapman-Maxwell法对流域日径流进行基流分割，并在分离径流事件的基础上，探究径流事件对降水的响应规律．结果表明:洮儿河流域降水、径流与基流均呈现下降趋势，且径流、基流与降水均检测到减小突变；基流维持径流过程的连续性，基于日径流序列，共分离出72次径流事件，均由多次降水导致，降水总量显著影响最大径流、最大基流；受土壤含水量和流域储水量等因素影响，径流对降水的响应具有明显的阈值特征．因此，在气候变化、人为干扰等不确定因素影响下，深入理解水文过程动态变化与生态性能指标之间的内在联系，有助于河流生态的保护和恢复．本文研究结果可加深不同流域产流机制和径流对降水响应的理解，为维持河道生态系统健康提供一定理论依据和实践参照． 

Study on runoff event response to precipitation in the Taoer River basin,China

The Chapman-Maxwell method (the CM filter) with recession constant calculated from Automatic Baseflow Identification Technique (ABIT) was used to separate baseflow from daily runoff at the Taonan hydrological station in Taoer River basin．Time series-based rainfall-runoff events were separated to explore runoff event response to precipitation． Annual precipitation, runoff and baseflow were found to show decreasing trends, with abrupt decreases detected in all three．Baseflow was found to maintain continued runoff process, with a total number of 72 events being identified from daily series of streamflow．A strong correlation of the volume of precipitation (P_tot) to maximum runoff (Q_max) and maximum baseflow (Q_Bmax) was observed．Runoff event response to precipitation showed marked threshold characteristics, being affected by soil moisture content and watershed water storage．Runoff process was found to be affected by climate change and human disturbance, therefore linking dynamic hydrological changes to ecological indexes was helpful to protect river ecology．These data will help to understand runoff generation and hydrological connectivity, and provide certain theoretical and practical references to maintain river ecosystem health．