Mapping the spatial variation of soil water content at the field scale with different ground penetrating radar techniques
Mapping the spatial variation of soil water content at the field scale with different ground penetrating radar techniques
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DOI：
10.1016/j.jhydrol.2007.03.013
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发表时间：
2007-07-15
影响因子：
6.4
通讯作者：
Vereecken, H.
中科院分区：
文献类型：
--
作者：
Weihermueller, L.;Huisman, J. A.;Vereecken, H.
两个探地雷达（GPR）技术被用来估计浅层土壤含水量在现场尺度。第一种技术是基于地面波的速度测量与双基地脉冲雷达连接到450兆赫地面耦合天线。第二种技术是基于在0.8-1.6 GHz频率范围内的离地单站TEM喇叭天线的逆建模。数据收集在8米的部分灌溉密集研究地块和沿着4个148.5米的横断面。时域反射仪，电容传感器，和体积土壤样品被用作参考测量。研究的目的是测试的适用性地波方法和离地反演模拟方法在现场规模的土壤粉质壤土质地。由于探地雷达信号的强烈衰减，地波技术的结果很难解释，这与试验场地的粉砂壤土质地有关。地波技术的均方根误差为0.076米（3）米（-3）时，与TDR测量和0.102米（3）米（-3）时，与体积土壤样品相比。离地单站探地雷达测量的田间土壤含水量变异性小于参考测量值，与TDR测量值相比，均方根误差为0.053 m（3）m（-3），与体积土壤样品相比，误差为0.051 m（3）m（-3）。两次探地雷达测量结果之间的变异性更大，RSME为0.115 m（3）m（-3）。总之，这两种探地雷达方法都没有提供足够的空间信息，在田间尺度上的土壤含水量变化。试验场地粉砂、粘土含量高，资料质量差是地波法结果出现偏差的主要原因。其他原因是浅反射和干燥的上层土壤层，不能检测到的地波方法。在离地探地雷达的情况下，对干燥表面层的高灵敏度是观察到的偏差的最可能的原因。离地探地雷达的结果可能会得到改善，通过使用不同的天线，允许在较低的频率范围内的数据采集。(C)2007 Elsevier B. V.保留所有权利。
Two ground penetrating radar (GPR) techniques were used to estimate the shallow soil water content at the field scale. The first technique is based on the ground wave velocity measured with a bistatic impulse radar connected to 450 MHz ground-coupled antennas. The second technique is based on inverse modeling of an off-ground monostatic TEM horn antenna in the 0.8-1.6 GHz frequency range. Data were collected on a 8 by 9 m partially irrigated intensive research plot and along four 148.5 m transects. Time domain reflectometry, capacitance sensors, and volumetric soil samples were used as reference measurements. The aim of the study was to test the applicability of the ground wave method and the off-ground inverse modeling approach at the field scale for a soil with a silt Loam texture. The results for the ground wave technique were difficult to interpret due to the strong attenuation of the GPR signal, which is related to the silt Loam texture at the test site. The root mean square error of the ground wave technique was 0.076 m(3) m(-3) when compared to the TDR measurements and 0.102 m(3) m(-3) when compared with the volumetric soil samples. The off-ground monostatic GPR measured less within-field soil water content variability than the reference measurements, resulting in a root mean square error of 0.053 m(3) m(-3) when compared with the TDR measurements and an error of 0.051 m(3) m(-3) when compared with the volumetric soil samples. The variability between the two GPR measurements was even Larger with a RSME of 0.115 m(3) m(-3). In summary, both GPR methods did not provide adequate spatial information on soil water content variation at the field scale. The main reason for the deviating results of the ground wave method was the poor data quality due to high silt and clay content at the test site. Additional reasons were shallow reflections and the dry upper soil layer that cannot be detected by the ground wave method. In the case of off-ground GPR, the high sensitivity to the dry surface layer is the most likely reason for the observed deviations. The off-ground GPR results might be improved by using a different antenna that allows data acquisition in a lower frequency range. (C) 2007 Elsevier B.V. All rights reserved.