用分形特征参数定量描述土壤水流运动的非均匀程度

通过田间条件下开展的7个碘-淀粉染色示踪试验,研究了入渗初始条件和边界条件对土壤水流运动非均匀特征的影响.同时采用土壤水实际入渗深度分布非均匀系数(C_(ua))和活动流场模型(ARM)分形特征参数(γ)来定量描述不同入渗条件下土壤水流动的非均匀程度.研究结果显示,不同条件下,γ和C_(ua)有着相同的变化趋势,γ能正确描述土壤水流运动的宏观非均匀特征;较低的土壤水初始饱和度引起较显著的土壤水非均匀流动;在相同土壤水初始饱和度条件下,土壤水流运动的非均匀程度随着入渗水量的增大而先增大后减小.

Characterizing soil water flow heterogeneity using fractal characteristic parameter

A total of 7 iodine-starch staining experiments were conducted to study the heterogeneity of soil water flow affected by the initial (initial water content) and boundary (infiltration amount) conditions. A heterogeneity coefficient of real infiltration depth distributions ( C_(ua) ) and the fractal characteristic parameter of the active region model (γ) were used to characterize the heterogeneity of the preferential flow patterns quantitatively. The research indicated that, the fractal characteristic parameter captured the macroscopic heterogeneity of the flow patterns well and displayed the same change trend with C_(ua) , under different infiltration conditions. With a lower initial soil water saturation, the flow patterns became more heterogeneous, corresponding to a larger γ value. Under the same initial soil water saturation, flow heterogeneity increased firstly and then decreased with the increase of infiltration amount.