On the reliability of current GPR ground wave methods for determining near-surface water contents

Abstract

We explore the stability of the Ground-Penetrating Radar (GPR) ground wave signal and its applicability for measuring near-surface water contents along a 0.6 km long measurement line, crossing several vegetated sand dunes at a semi-desert site in Northwestern China. We find that the direct ground wave signal is a stable proxy for measuring near-surface soil moisture. However, the absolute water content may be difficult to establish without additional auxiliary information (e.g. through TDR point measurements). This is mainly due to limitations of the current feature-to-feature evaluation of the airand ground wave wavelets.

Quantitative high-resolution observations of soil water dynamics in a complicated architecture using time-lapse ground-penetrating radar

“…Provided highly accurate GPR observations are available over a preferably large range of soil water contents, monitoring soil water dynamics with GPR in connection with a suitable inversion scheme can in principle give access to soil hydraulic properties. So far, several studies have shown promise in inferring near-surface soil hydraulic properties based on time-lapse observations of soil water dynamics, using borehole GPR (e.g., Kowalsky et al, 2005;Rucker and Ferré, 2004;Looms et al, 2008), off-ground GPR (e.g., Jadoon et al, 2008;Lambot et al, 2009;Tran et al, 2014), and multi-offset on-ground GPR (Busch et al, 2013). Follow-ing a different approach, Moysey (2010) estimated soil hydraulic properties based on hydrologic trajectories derived from fixed-offset time-lapse monitoring of an infiltration experiment by on-ground GPR.…”