Multi‐Elevation UAV‐Based Frequency Domain Electromagnetic Method for Data Calibration and Field Investigation

Cheng, Qinbo and Ma, Zhijin and Binley, Andrew and Chai, Jiayun and Liu, Jintao and Zhang, Zhicai and Chen, Xi (2025) Multi‐Elevation UAV‐Based Frequency Domain Electromagnetic Method for Data Calibration and Field Investigation. Water Resources Research, 61 (9): e2024WR039. ISSN 0043-1397

Text (2024WR039579.pdf)
2024WR039579.pdf - Published Version
Available under License Creative Commons Attribution-NonCommercial-NoDerivs.
Download (3MB)

Abstract

Plain Language Summary: Geophysical methods are now routinely used to measure the spatial (and temporal) variation of a proxy (e.g., electrical conductivity) that can often provide valuable insight into properties and states of interest (e.g., soil moisture, groundwater salinity, etc.). This study introduces an innovative method that uses drones equipped with an electromagnetic induction (EMI) instrument to map the electrical conductivity of shallow soils. Traditionally, EMI instruments are used as handheld devices and data are collected from one height above ground level. This can limit the amount of information obtained. In addition, in some cases access to areas of interest can be limited. In our new approach, drones fly along predetermined routes at different heights to collect multiple sets of EMI data. This multi‐elevation strategy not only allows greater areal coverage but also improves the quality of the data by calibrating the measurements from the instrument's different sensors. Field tests were conducted at two locations‐a riparian zone along the Yangtze River and a geothermal area in Tibet. The surveys reveal spatial variation in subsurface electrical conductivity that are related to the presence and movement of fluids in the ground. The drone‐based EMI system offers a powerful tool for water resource management.