We show the potential of on-ground Ground-Penetrating Radar (GPR) to identify the parameterisation of the soil water retention curve, i.e. its functional form, with a semi-quantitative analysis based on numerical simulations of the radar signal. An imbibition and drainage experiment has been conducted at the ASSESS-GPR site to establish a fluctuating water table, while an on-ground GPR antenna recorded traces over time at a fixed location. These measurements allow to identify and track the capillary fringe in the soil. The typical dynamics of soil water content with a transient water table can be deduced from the recorded radargrams. The characteristic reflections from the capillary fringes in model soils that are described by commonly used hydraulic parameterisations are investigated by numerical simulations. The parameterisations used are (i) full van Genuchten, (ii) simplified van Genuchten with im/i = 1 ? 1/in/i and (iii) Brooks–Corey. All three yield characteristically different reflections, which allows the identification of an appropriate parameterisation by comparing to the measured signals. We show that for the sand used here, these signals are not consistent with the commonly used simplified van Genuchten parameterisation with im/i = 1 ? 1/in/i.
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机译:我们通过基于雷达信号数值模拟的半定量分析,展示了地面探地雷达(GPR)识别土壤保水曲线的参数化(即其功能形式)的潜力。已在ASSESS-GPR站点进行了吸水和排水实验,以建立波动的地下水位,而地面GPR天线则记录了固定位置随时间变化的痕迹。这些测量结果可以识别并跟踪土壤中的毛细边缘。可以从记录的雷达图推导出具有瞬时地下水位的土壤水分的典型动态。通过数值模拟研究了模型土中毛细条纹的特征反射,这些反射由常用的水力参数化描述。使用的参数化是(i)完整的van Genuchten,(ii) m i> = 1的简化的van Genuchten。 1 / n i>和(iii)布鲁克斯-科里。所有这三个都产生特征不同的反射,这允许通过与测量信号进行比较来识别适当的参数。我们表明,对于此处使用的沙子,这些信号与 m i> = 1?时常用的简化van Genuchten参数化不一致。 1 / n i>。
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