Monitoring near-surface soil water content using an innovative perforated cylinder coaxial dielectric sensor
Monitoring near-surface soil water content using an innovative perforated cylinder coaxial dielectric sensor
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使用创新的穿孔圆筒同轴介电传感器监测近地表土壤含水量
DOI：
10.1016/j.jhydrol.2019.04.020
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发表时间：
2019-06
影响因子：
6.4
通讯作者：
Cheng Qiang
中科院分区：
文献类型：
--
作者：
Chen Chao;Yan Xiaofei;Ma Yihan;Yu Song;Xu Qiang;Grantz David A;Lammers Peter Schulze;Wang Zhongyi;Sun Yurui;Cheng Qiang
近地表土壤含水率(NSWC)是表征水文过程、土壤-大气边界水汽交换和潜在生物生产力的重要参数。本文设计了一种基于介质的频域阻抗传感器，工作频率为100MHZ，采用了新颖的同轴探头设计，并在电路板中嵌入了温度传感器。该穿孔圆柱体同轴(PCC)传感器可同时测量体积土壤水分(VSWC)和温度。温度测量允许对电路板的温度响应和土壤水的介电常数进行信号校正。我们对PCC传感器的性能进行了表征，并将其与替代的3针和2针电极FD阻抗传感器进行了比较，每种传感器都使用了性能相似的电路板。进行了一系列的理论分析和实验，包括(I)传感器的校准，(Ii)温度效应及其校正，(Iii)通过模拟分析和逐步土壤去除(SSR)测试每个传感器所感知的土壤体积，以及(Iv)三种传感器用于NSWC测量的精度比较。校准结果验证了PCC型、3针型和2针型探头适用于VSWC(均方根 ≤ 0.0142 cm3 cm−3)的测量。利用高频结构模拟器软件(HFSS)进行的仿真分析表明，新型PCC探头具有对称的电场分布，完全包含在圆柱体内，避免了电场在土壤-大气界面泄漏到空气中，并消除了传感体积对VSWC的依赖。SSR测试结果表明，PCC探头接收电极外的电场分布可以忽略不计，而两个针型电极的电场分布在接收电极外的距离取决于垂直驻波系数(即当可变驻波系数 >； 0.17 cm3 cm−3时，3针高达8 mm，2针设计高达11 mm)，这与模拟分析一致。此外，新的PCC探头提供了比3针或2针探头更准确的NSWC测量，因为电场包含在穿孔圆柱体内，避免了电场泄漏，并固定了独立于VSWC的传感土壤体积。当水平安装在地表以下至少11 mm的土壤中时，销钉结构的探头似乎表现最好。
Near-surface soil water content (NSWC) is an important parameter for characterizing hydrological processes, water and vapor exchange at the soil-atmosphere boundary, and potential biological productivity. Here we develop a dielectric based frequency-domain (FD) impedance sensor operating at 100 MHz, with a novel coaxial probe design and a temperature sensor embedded in the circuit board. This perforated cylinder coaxial (PCC) sensor provides simultaneous measurements of volumetric soil water content (VSWC) and of temperature. The temperature measurement allows signal correction for the temperature response of the circuit board and of the permittivity of soil water. We characterize the performance of the PCC sensor and compare it with alternative 3-pin- and 2-pin-electrode FD impedance sensors each using a similarly performing circuit board. A series of theoretical analyses and experiments were conducted, including (i) sensors calibration, (ii) temperature effects and their correction, (iii) soil volume sensed by each sensor through simulation analysis and a stepwise soil removal (SSR) test and (iv) accuracy comparison of the three sensors when applied for the NSWC measurements. The calibration results verified that the PCC, 3-pin and 2-pin probes were suitable to measure VSWC (RMSE ≤ 0.0142 cm3cm−3). The simulation analysis using High Frequency Structure Simulator software (HFSS) indicated that the novel PCC probe had a symmetrical distribution of the E-field, wholly contained within the cylinder, avoiding leakage of the E-Field into air at the soil-atmosphere interface and removing the dependency of sensed volume on VSWC. The results of the SSR test showed that the E-field distributed outside the receiving electrode of the PCC probe could be ignored whereas that of both pin-type electrodes was distributed outside of the receiving electrode to a distance that depended on VSWC (i.e. up to 8 mm for 3-pin and up to 11 mm for 2-pin designs when VSWC > 0.17 cm3cm−3), which corresponds to the simulation analysis. Moreover, the new PCC probe provided more accurate NSWC measurement than 3-pin or 2-pin probes because the E-field was contained within the perforated cylinder, avoiding E-field leakage and fixing sensed soil volume independent of VSWC. The pin-structure probes appear to perform best when installed horizontally in the soil at least 11 mm below the surface.
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DOI：
10.3390/rs9060580
发表时间：
2017-06
期刊：
Remote. Sens.
影响因子：
--
作者：
C. Koyama;Hai Liu;Kazunori Takahashi;M. Shimada;Manabu Watanabe;T. Khuut;Motoyuki Sato
通讯作者：
C. Koyama;Hai Liu;Kazunori Takahashi;M. Shimada;Manabu Watanabe;T. Khuut;Motoyuki Sato
影响因子：
6.4
作者：
DEAN, TJ;BELL, JP;BATY, AJB
通讯作者：
BATY, AJB
影响因子：
13.5
作者：
Liu, WD;Baret, F;Zhang, B
通讯作者：
Zhang, B
DOI：
10.1109/tgrs.1985.289498
发表时间：
1985-01-01
影响因子：
8.2
作者：
DOBSON, MC;ULABY, FT;ELRAYES, MA
通讯作者：
ELRAYES, MA
影响因子：
13.5
作者：
Albergel, Clement;de Rosnay, Patricia;Wagner, Wolfgang
通讯作者：
Wagner, Wolfgang