GPR based RTM imaging technology for estimating rhizome diameters and application in the western China mining area  

基于GPR逆时偏移成像技术的西部矿区植物根系直径估算试验研究

作　　者：Cui Fan Li Shuai Yuan Jiong-Xuan Bai Jie-Bin Zhao Yu-Xuan Zhou Ying-Ging 崔凡;李帅;原炯轩;白洁玢;赵煜轩;周莹庆(煤炭开采水资源保护与利用国家重点实验室,北京100000;中国矿业大学(北京)煤炭资源与安全开采国家重点实验室,北京100083;中国矿业大学(北京)地球科学与测绘工程学院,北京100083)

机构地区：[1]State Key Laboratory of Water Resource Protection and Utilization in Coal Mining,Beijing 100000,China [2]State Key Laboratory of Coal Resources and Safe Mining,CUMTB,Beijing 100083,China [3]College of Geoscience and Surveying Engineering,China University of Mining and Technology,Beijing 100083,China

出　　处：《Applied Geophysics》2020年第1期154-166,170,共14页应用地球物理（英文版）

基　　金：supported by the Open Foundation of the State Key Laboratory of Water Resource Protection and Utilization in Coal Mining(Gant No.SHJT-16-30.18);National Natural Science Foundation of China(No.41602364);National Key R&D Program of China(No.2016YFC0801404);State Key Laboratory of Coal Resources and Safe Mining,China University of Mining and Technology(Beijing)(No.SKLCRSM16DCB14,SKLCRSM17DC01)。

摘　　要：The rhizome functions are of great significance to the ecological protection of the western China mining area,whose ecological management can be provided with technical support via accurate calculations of the rhizome biomass.The rhizome diameter is an important index parameter of rhizome biomass.In this study,we propose an estimation of rhizome diameters based on ground penetrating radar(GPR)-based reverse time migration(RTM)imaging technology.First,the spatial distribution of shallow rhizomes is simulated using the finite difference time domain method.The simulation data are examined via RTM imaging and single-channel rhizome analysis to obtain the rhizome index parameters:Δh,the width of the maximum positive peak amplitude measured at an amplitude of zero,andΔH,the distance between the zero-amplitude position above the largest positive peak in the shallow region and the zero-amplitude position below the largest positive peak in the deeper region.The experiments of physical models verify the effectiveness of the two parameters(Δh andΔH).and indicate that the values ofΔh andΔH are independent of the rhizome burial depth;instead,they are only related to the diameter of the rhizome.For both the numerical simulations and the physical model experiment,the estimation errors ofΔh andΔH for the rhizome diameters can be constrained to less than 6%and 5%,respectively,which shows that the estimation of the rhizome diameters using GPR based RTM imaging technology is reasonable and effective and its high estimation accuracy meets the technical requirements.植物根系的固砂、存水以及防止土壤沙漠化等功能对西部矿区的生态保护具有重要意义,精确计算植物地下根系的生物量可以对矿区的生态治理提供一定的技术支撑。而植物根系的直径作为生物量计算的一个重要指标参数,直接影响着根系生物量的计算结果。本研究提出了一种基于探地雷达逆时偏移(RTM)(成像技术的植物根系直径估算方法。首先基于时域有限差分(FDTD)原理对浅层地下植物根系的空间分布情况开展数值模拟,获取绕射波双曲线图像。然后结合RTM成像条件对数值模拟数据进行成像与单道分析,获取直接反映植物根系直径的指标参数:最大正波峰振幅为零的两个位置之间的距离(△h)和浅部最大正波峰上方的零振幅位置与深部最大正波峰下方的零振幅位置之间的距离(△H),并通过物理模型验证了数值模拟结果分析中求得的两个指标参数△h、△H对植物根茎直径估算的有效性。综合结果表明:指标参数△h和△H的值与根茎埋深无关,只与样本直径大小有关。当根茎直径在5 cm及以下时,△h可作为描述直径的指标参数;当根茎直径在5 cm以上时,△H可作为描述直径的指标参数。针对数值模拟和物理模型探测两种数据,△h和△H对植物根茎直径的估算误差分别可控制在6%和5%以下,这表明以探地雷达RTM成像为基础建立的根径估算方法是合理且有效的,估算精度满足技术要求。

关 键 词：Ground penetrating radar western China mining area RTM imaging rhizome diameter estimation 

分 类 号：Q948[生物学—植物学] X171[环境科学与工程—环境科学]