Hills Danny, Lawless Becan, Khangerey Rauan, Wilkinson Jeremy, Marsh Liam A
Department of Electronic and Electrical Engineering, University of Manchester, Manchester M13 9PL, UK.
British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK.
Sensors (Basel). 2025 Jan 16;25(2):510. doi: 10.3390/s25020510.
Frequency-domain electromagnetic induction (EMI) is routinely used to detect the presence of seawater due to the inherent electrical conductivity of the seawater. This approach is used to infer sea-ice thickness (SIT). A time-domain EMI sensor is presented, which demonstrates the potential for correlating the spectroscopic properties of the received signal with the distance to the sea surface. This is a novel approach to SIT measurement, which differs from existing methods in that it uses measurements from 10 kHz to 93 kHz rather than a single frequency. The sensor was tested at a tidal pool containing seawater and measured to have a conductivity of 57.3 mS/cm. Measurements were performed at a range of heights between 0.2 m and 1.9 m above the sea surface and for inclinations from 0° to 45°. These measurements were correlated with Finite Element Modeling (FEM) simulations performed in COMSOL. The measured and simulated datasets are presented along with a proposed form of post-processing, which establishes a correlation between the distance to the sea surface and the measured EMI response. This forms a proxy measurement for the absolute distance from the EMI sensor to the sea surface. Because the air gap between the sensor and the seawater is indicative of the properties of sea ice, this study demonstrates a novel approach to non-destructive measurement of sea-ice thickness. The measurements show that this distance to the sea surface can be estimated to within approximately 10% of the known value from 0.2-1.5 m and 15% from 1.5 to 1.9 m.
频域电磁感应（EMI）通常用于检测海水的存在，这是由于海水固有的电导率。这种方法被用于推断海冰厚度（SIT）。本文介绍了一种时域EMI传感器，它展示了将接收到的信号的光谱特性与到海面的距离相关联的潜力。这是一种测量海冰厚度的新方法，它与现有方法的不同之处在于它使用10 kHz至93 kHz的测量频率，而不是单一频率。该传感器在一个装有海水的潮汐池中进行了测试，测得电导率为57.3 mS/cm。测量在海面上方0.2 m至1.9 m的一系列高度以及0°至45°的倾斜角度下进行。这些测量结果与在COMSOL中进行的有限元建模（FEM）模拟相关联。给出了测量数据集和模拟数据集以及一种建议的后处理形式，该后处理建立了到海面的距离与测量的EMI响应之间的相关性。这形成了一种从EMI传感器到海面绝对距离的替代测量方法。由于传感器与海水之间的气隙表明了海冰的特性，本研究展示了一种非破坏性测量海冰厚度的新方法。测量结果表明，到海面的距离在0.2 - 1.5 m范围内可估计到已知值的约10%以内，在1.5至1.9 m范围内可估计到15%以内。
