黄土地区土壤含水量消退系数的变化规律与产流计算

Regularity of Variation of Recession Coefficient of Autecedent Precipitation in Soil and Runoff Yield Estimating for Loess Regions

土壤前期影响雨量的消退系数K是产流模型中的参数之一,它直接影响产流成果。以南京水文水资源所产流模型为例,对团山沟流域的K值与产流进行了计算,并得到如下认识:1)单点K值与土层深度成线性递增关系,而与初始土壤含水量呈递减关系。只有当土层取得足够厚时,计算的K值才能够较确切地反映蒸散发的影响,这个土层深度要依靠降雨入渗锋面的分析来确定;2)数域面平均K值应与数域产流模型结合考虑,作为模型参数优选确定。

The recession coefficient of antecedent precipitation in soil K, one of the factors affecting runoff yeild, brings influnce on runoff yeild estimating. Using a model developed by The Nanjing Research Institute of Hydrology and Water Re sources, calculation of runoff yeild and value of K was carried out for Tuanshangou basin, and following knowledge was obtained: 1) Single K value linear increasing with soil depth and decreasing with preliminary water content of soil. Calculated K value can include the effect of evaporation relevantly only in case of enough soil depth, which, in turn, is determined through analysing infiltration front; 2) Mean value of K for the basin, being considered together with pattern of runoff yeild, to be chosen-optimized as a parameter for the runoff yield model.