Estimating Water Content of Unsaturated Sandy Soils by Ground-Penetrating Radar During an Infiltration Experiment

Summary This study shows how to estimate water content of unsaturated sandy soils from ground-penetrating radar (GPR) data acquired during water infiltration experiment. Using the Topp equation, water content can be converted to dielectric permittivity. Afterwards, based on 1D forward modeling method, a GPR synthetic trace is generated. Finally, a trial-and-error match of modeled and observed GPR traces is performed to estimate the optimum set of parameters characterizing the materials composing the soil. According to the comparison of the modeling signal and the real signal, we go back to update the model and water content. Repeating the procedure until the modeling signal fits the real signal very well. We used this procedure to obtain the water content of unsaturated sandy soils. We present the setup experiment carried out for an unsaturated sandy soil. In order to follow the water front progression in depth, we picked up four real measured GPR traces at different injected times and by modeling obtained the water content for each trace.