Qualitative monitoring of the water content evolution in an inhomogeneous soil column

A microwave imaging problem is considered where a soil column is surrounded by a metallic circular enclosure. This system is presently being developed to demonstrate the potentiality of non-invasive microwave imaging systems for volumetric water content monitoring. The final goal is to retrieve soil moisture information as it is an important parameter for understanding fluid flows in the soil as well as the water uptake by plant roots. Here, we address the qualitative part of the problem with the help of a rapid and rather robust sampling methods: the Linear Sampling Method (LSM) and the MUSIC method. These methods are tested for the following configuration: one water source diffuses in a heterogeneous background. We show that, to a certain extent, the evolution of the soil water content can be qualitatively monitored with the LSM. Moreover, we propose a quick way for detecting the position of the water source inside the soil column.