土壤入渗性能线源测量方法的近似算法研究

土壤入渗性能的确定对于水文过程模拟,如地表产流、土壤侵蚀以及降雨向土壤水和地下水的转换等均具有十分重要的意义。本文提出了一种土壤入渗性能线源入流测量方法的快速近似算法。该方法在水量平衡原理的基础上,将各时刻的土壤入渗率在湿润地表的空间范围内进行平均,确定土壤入渗性能随时间的变化过程;所提出的新的计算模型可以简单地计算土壤入渗性能。文中利用3组土壤入渗性能线源入流测量方法得到的试验数据,将该近似算法得到的结果与之前提出的数值解法计算得到的结果进行比较,并基于水量平衡原理估计了数值方法和该近似算法的误差。结果表明,该近似算法得到的结果比数值解法得到的结果偏大,比实际供水量偏大25.3%;该近似算法的计算结果稳定,可以作为试验过程中数值计算得到的土壤入渗性能的参照值。

An approximation approach for determination of soil infiltrability measured with linear source method

The determination of soil infiltration capacity is of great importance for modeling hydrological processes such as overland flow, soil erosion and the transformation of rainfall into soil water or ground water. A new method is proposed for the fast approximation of soil infiltrability. The new method was derived using the mass balance when the soil infiltration rates at different locations within the wetted area were averaged to quantify the temporal infiltration process. The proposed new mathematic model provides a simple but useful method for determining infiltrability. Data from three linear source experiments were used to compare the results from this new approximation method with those estimated with the numerical method. The errors of the infiltrated water as computed with the numerical method and this new approach were estimated with water balance method. The results indicate that the soil infiltration rates estimated with the approximation method are very stable though to some extend it is higher than those estimated with the numerical method, with an estimate error of 25.3% higher than the supplied water. This new method can also be used as a necessary reference for the results estimated with numerical method in the linear source experiments.