Department of Civil and Environmental Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI 53706.
Ground Water. 2012 May-Jun;50(3):340-7. doi: 10.1111/j.1745-6584.2012.00928.x. Epub 2012 Mar 28.
Characterizing both spatial and temporal soil moisture (θ) dynamics at site scales is difficult with existing technologies. To address this shortcoming, we developed a distributed soil moisture sensing system that employs a distributed temperature sensing system to monitor thermal response at 2 m intervals along the length of a buried cable which is subjected to heat pulses. The cable temperature response to heating, which is strongly dependent on soil moisture, was empirically related to colocated, dielectric-based θ measurements at three locations. Spatially distributed, and temporally continuous estimates of θ were obtained in dry conditions (θ≤ 0.31) using this technology (root mean square error [RMSE] = 0.016), but insensitivity of the instrument response curve adversely affected accuracy under wet conditions (RMSE = 0.050).
用现有技术很难在现场尺度上描述土壤水分（θ）的时空动态。为了解决这个缺点，我们开发了一种分布式土壤水分传感系统，该系统采用分布式温度传感系统来监测沿埋地电缆长度每隔 2 米的热响应，该电缆受到热脉冲的影响。电缆对加热的温度响应强烈依赖于土壤水分，通过与三个位置的共置介电θ测量值进行经验相关，得到了空间分布和时间连续的θ估计值。在干燥条件下（θ≤0.31），使用这项技术获得了θ的空间分布和时间连续估计值（均方根误差 [RMSE] = 0.016），但仪器响应曲线的不敏感性会对潮湿条件下的精度产生不利影响（RMSE = 0.050）。
