Translation algorithm of the apparent conductivity using the frequency-domain electromagnetic method of a magnetic dipole

Abstract

In this paper, based on the expression of the relative magnetic anomaly for a frequency-domain magnetic dipole in homogeneous half-space under quasi-static conditions, we derive higher-order approximate formulas of the apparent conductivity. At the same time, it is found that there is a translational and expansionary characteristic between the response curve of the relative magnetic anomaly for the frequency-domain magnetic dipole and underground conductivity and observation frequency. Accordingly, we propose a translation algorithm that can directly calculate the apparent conductivity. By processing the data of the theoretical models and the GEM-2 electromagnetic measurement data from the detection of the thickness of Arctic sea ice, we validate the effectiveness of this method. In comparison with the conventional and the higher-order approximate calculation formula of the apparent conductivity, this method features fast computation speed, high accuracy, and insensitivity to the instrument height. Meanwhile, it also helps explain the burial depth of the conductive layer. Therefore, it is worth popularizing and applying in practical applications.