丰满流域春季径流水源及产流模式分析

Analysis for the composition of spring runoff in Fengman Basin

春季径流主要来源于融雪水和冻土条件下的降雨径流,但是,如何定量进行各产流模式阶段划分和各水源量的估算,一直是春季径流研究的挑战。为了评价多年平均状态下的春季水源组成及其产流模式阶段,结合丰满流域1944—2017年的日径流量资料,根据典型年(2017年)春季日径流过程总结出东北春季径流过程由3种产流模式构成,即融雪产流模式、冻土条件下融雪-降雨产流模式、冻土条件下降雨产流模式。通过Eckhardt递归数字滤波法进行基流分割,定义地下径流与总径流之比为基流比,根据总径流量和基流比曲线变化趋势分析产流模式起止日期及历时,并采用箱形图对历年产流模式起止日期及历时进行统计分析。结果表明:丰满流域在多年平均状况下,融雪产流开始日期为3月21日,冻土条件下融雪、降雨产流开始日期为4月21日,融雪产流结束日期为5月11日,冻土消融日期为5月28日;融雪产流模式历时为31 d,冻土条件下融雪、降雨产流模式历时20 d,冻土条件下降雨产流模式历时18 d;多年平均状况下,丰满流域春季总径流中,融雪产流约占39.4%,冻土条件下融雪、降雨产流约占35.3%,冻土条件下降雨产流约占25.3%;丰满流域年总径流中,融雪产流约占10.3%,冻土条件下融雪、降雨产流约占9.2%,冻土条件下降雨产流约占6.6%。研究成果对北方地区流域春汛来水预报具有参考价值。

In order to reveal the intrinsic formation mechanism of spring runoff change,the spring flood forecasting is more complicated because of the multi-component water source,many influencing factors and the complex process of each factor,based on the daily runoff data of Fengman basin from 1944 to 2017,the spring runoff process in Northeast China consists of three kinds of runoff mode,that is,snowmelt runoff mode,snowmelt and rainfall runoff combined mode and rainfall runoff mode under permafrost condition according to the typical year(2017)spring daily runoff process.Eckhardt recursive digital filtering method was used to segment the base flow,and the ratio of underground runoff to total runoff was defined as the base flow ratio.According to the variation trend of the curve of total runoff and base flow ratio,the starting and ending dates of runoff modes and the duration were analyzed.By means of the box-plot,the starting and ending dates of runoff modes and the duration were statistically analyzed.The results show that in the Fengman basin,under the average condition of many years,the beginning date of snowmelt runoff is March 21,the beginning date of snowmelt and rainfall runoff combined under permafrost conditions is April 21,the ending date of snowmelt runoff is May 11,and the date of frozen soil melting is May 28.The snowmelt mode lasted 31 days,snowmelt and rainfall runoff combined mode under permafrost condition lasted 20 days,and rainfall runoff under permafrost condition mode lasted 18 days.On the average condition of many years in Fengman basin.During the spring runoff process,snowmelt stage is about 39.4%,snowmelt and rainfall runoff combined stage under permafrost condition is about 35.3%and rainfall runoff stage under permafrost condition is about 25.3%;during the total annual runoff process,snowmelt stage is about 10.3%,snowmelt and rainfall runoff combined stage under permafrost condition is about 9.2%and rainfall runoff stage under permafrost condition is about 6.6%.The research results have reference value or guiding significance for the basic work of spring flood forecasting.