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| 基于探地雷达的田块尺度下不同深度土壤含水量监测 | |
| 作者姓名： | 张文瀚 杜克明 孙彦坤 刘布春 孙忠富 马浚诚 郑飞翔 |
| 作者单位： | 东北农业大学 资源与环境学院，黑龙江 哈尔滨 150030 中国农业科学院农业环境与可持续发展研究所，北京 100081 |
| 摘 要： | 为确定田块尺度下探地雷达对不同深度及相邻反射层间土壤含水量的反演精度、有效反演深度、最佳反演深度及最优反演模型,本研究采用1000 MHz中心频率探地雷达设备,分别在无降雨偏干旱土壤和降雨后湿润土壤两种条件下,在选定农田区域基于共中心点法采集雷达波数据,提取有效地表波与反射波数据,通过双曲线拟合法分别获取不同深度反射层... |
| 关 键 词： | 探地雷达 土壤含水量监测 共中心点法 最佳反演深度 最优反演模型 Roth模型 |
| 收稿时间： | 2021-12-25 |
Monitoring Specified Depth Soil Moisture in Field Scale with Ground Penetrating Radar |
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| Authors: | ZHANG Wenhan DU Keming SUN Yankun LIU Buchun SUN Zhongfu MA Juncheng ZHENG Feixiang |
| Institution: | College of Resources and Environment, Northeast Agricultural University, Harbin 150030 Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081 |
| Abstract: | Ground-penetrating radar (GPR) is one of the emerging technologies for soil moisture measurement. However, the measurement accuracy is difficult to determine due to some influence factors including radar wave frequency, soil texture type, etc. The GPR equipment with 1000 MHz center frequency and the measurement method of common midpoint (CMP) were adopted in the research to collect radar wave raw data in the selected field area under arid soil and moist soil conditions. The transmitter and receiver antennas of the GPR equipment were moved 0.01 m respectively in opposite directions on each radar wave raw data collection. Therefore, a CMP radar image consisted of 100 pieces of radar wave raw data by increasing the antenna distance from 0 m to 2 m. Each radar wave raw data indicated that the radar waves were reflected in the reflective layer with different dielectric constant under the same antenna distance. And the reflected and refracted radar waves were acquired by the receiving antenna at different two-way travel time respectively, and recorded in the computer. The collection of CMP soundings aimed to determine the inversion accuracy, optimum inversion depth, effective inversion depth and optimal inversion model of soil moisture content at different depth ranges and adjacent reflective layers by GPR at field scale. The reflected and refracted radar wave data were extracted from the raw data. The velocities of the surface waves and reflected waves were obtained respectively from the line slope of the surface wave data and the hyperbolic curves fitting of the reflected wave data. In addition, the relative dielectric constant of the soil at specified depth were deduced according to the soil dielectric constant and its reflected wave velocity. Moreover, 4 different models including Topp, Roth, Herkelrath and Ferre were used to figure out the soil volumetric water content inversion. Meanwhile, the measured data of soil volumetric moisture content obtained by oven drying method were used to verify the accuracy of the inversion results. The results showed that the effective inversion depth of 1000 MHz GPR ranged from 0 to 50 cm. The best inversion depth was 50 cm in arid soil and 40 cm in moist soil. The Roth model had the best correlation and stability with the highest R2 was 0.750, the Root Mean Square Error (RMSE) was 0.0114 m3/m3 and the lowest Relative Error (RE) was 3.0%. The GPR could possess the capacity of quick, precise and non-destructive measurement of specified depth soil moisture in field scale. The inversion model of soil moisture content needs to be calibrated according to different soil conditions. |
| Keywords: | ground penetrating radar soil water content monitoring common midpoint optimum inversion depth optimum inversion model Roth model |
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