Soil Characteristics Measurements with Ground Penetrating Radar: A Review
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摘要: 总结了探地雷达技术(Ground Penetrating Radar, 简称GPR)使用反射波、地波、反射系数、全波形反演和早期信号分析进行土壤特性研究的方法,在详细介绍基本原理的基础上,通过分析近年来的研究实例展示GPR探测土壤特性的能力和局限性:基于信号速度的分析方法应用广泛,数据获取和处理简单,但结果具有主观性,受实验环境的限制;基于信号幅度的分析方法受水分分布和表面粗糙度的影响,容易出现低估的现象;全波形反演和早期信号分析方法的提出强调了GPR探测中数据获取和处理的重要性,为此应设计新的数值分析模型和数据处理方法,提高数据采集速度和雷达测量精度。Abstract: This review summarized the methods of estimating soil characteristics using ground penetrating radar (GPR), such as analyses of reflections, ground wave, surface reflection coefficient, full-waveform inversion and early-time signal analysis. This study analyzed the basic principle and method using GPR to detect soil characteristics in detail, and reviewed the ability and limitation of GPR by summarizing latest studies. The approaches based on signal velocity analysis were widely used; however, the results were subjective and limited by the experimental environment. The approaches based on reflection amplitude analysis were limited by varying soil water contents with depths and surface roughness, and which leaded to a decrease in reflection coefficient. The full waveform inversion and early-time signal analysis methods emphasized the importance of data acquisition and processing in detection. More complex numerical analysis models and data processing approaches should be developed to improve data acquisition speed and measurement accuracy.
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Key words:
- GPR /
- Soil water content /
- Soil layer thicknesses /
- Soil salinity /
- Soil texture /
- Root system
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图 1 土壤含水率的3D可视化,表面空心椭圆为覆盖植被的位置和大小[16]
Figure 1. The 3D visualization of soil water content. Open ovals on the surface represent the distribution and size of shrub canopies.
图 3 土壤介电常数对早期信号幅度的影响[74]
Figure 3. Influence of soil dielectric constant on the amplitude of the early-time signal
图 4 频率峰值的偏移[89]
Figure 4. The shift in the frequency peak.
表 1 探地雷达技术探测土壤特性的研究汇总
Table 1. Summary of soil characteristics detected using GPR methods.
应用范围
Application方法
Method参考文献
Reference土壤含水率 反射波速度 刘等,2020;赵贵章等,2020;罗古拜等;2019;刘等,2018;Ercoli等,2018;
吴志远等,2017;陆等,2017;Koyama等,2017年;刘成禹等,2016;王前锋等,2013;
潘等,2012;Steelman等,2012;Wollschlager等,2010;Bradford等,2008。地波速度 曹棋等,2020;Koyama等,2017;陆等,2017;Mangel等人;2017;Terry等,2017;
Paz等,2017;Mertens等,2016;Ardekani等,2013;Steelman等,2012;
Pallavi等,2010;van der Kruk等,2010。表面反射系数 金光来等,2020;崔凡等,2018;吴志远等,2017;卢奕竹等,2017;马福建等,2014;
Ardekani等,2013;王前锋等,2013;Reppert等,2000。全波形反演 Klotzsche等,2018;齐等人;2018;Gueting等,2017;Tran等,2015;Ardekani等,2014;
Mourmeaux等,2014;Ardekani等,2013;Minet等,2012;Minet等,2011;Meles等,2010;
Muller等,2010;Lambot等,2008;Weihermüller等,2007;Lambot等,2004。早期信号分析 崔凡等,2018;Algeo等,2016;Comite等,2016;吴志远等,2015;Comite等,2014;
Ardekani等,2013;Di Matteo等,2013;Ferrara等,2013;Pettinelli等,2007;Grote等,2003。土壤层深度 信号反射技术 李俐等,2020;高强山等,2019;Comas等,2017;Rodriguez-Robles等,2017;
Comas等,2017;Simms等;2017张昊等,2016;夏银行等,2016;Andre等,2016;
李等,2016;张等,2014;Novakova等,2013;Simeoni等,2009。信号反演技术 André等,2016;André等,2015;Buchner等,2012。 有机层厚度 André等,2016;Li等,2015;André等,2015;André,2014;Winkelbauer等,2011。 土壤盐分和质地 早期信号分析表面反射系数 马永辉等,2020;刘成禹等,2016;Rejsek等,2015;Busch等,2014;
Benedetto等,2013;Tosti等,2013;何瑞珍等,2011;Meadows等,2006。土壤根系 信号反射技术 刘等,2018;Rodriguez-Robles等,2017;Simms等,2017;Tanikawa等,2016;
Stover等,2016;Borden等,2016;李等,2016;Tardio等,2016;Freeland等,2015;
吴等,2014;朱等,2014;郭等,2013;Raz-Yaseef等,2013;崔等,2011。根直径和生物量 王明凯等,2020;刘等,2018;Rodriguez-Robles等,2017;Simms等,2017 ;
李等,2016;Stover等,2016;Tanikawa等,2016;Borden等,2016;崔等,2011。其他内容 张迪等,2020;罗古拜等,2019;刘等,2018;Comas等,2017;
Terry等, 2017;刘等,2016;Walter等,2016。表 2 GPR探测土壤含水率的5种方法
Table 2. Five methods of soil moisture estimation using GPR
方法
Methods适用条件
Applicable conditions优点
Advantages缺点
Disadvantages信号速度分析方法
——反射波足够的信号穿透力
清晰的介电常数对比度
明确反射器深度理论简单易懂
广泛用于探测SWC无法控制测量深度分辨率
多偏移量测量操作复杂
多通道测量需较大偏移量,会促进电磁波衰减信号速度分析方法
——地波不需要清晰的反射层
导波的分散特性空气波和地波难以区分
地波振幅衰减较快
出现导波时可能无法识别信号幅度分析方法
——表面反射系数精确的幅度测量
高频率天线− 容易低估介电常数 全波形反演 − 提高地下特征分辨率
数据反演计算精度高受土壤粗糙度和异质性的影响 早期信号分析 GPR信号的早期部分 解决地波空气波难以识别的问题
检查波形属性与土壤电磁特性的关系− -
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