2007 Volume 60 Issue 6 Pages 455-466
This paper reviews methods of measuring soil volumetric water contents and soil hydraulic properties, such as unsaturated hydraulic conductivity and water retention curve, in the vadose zone with non-invasive surface ground penetrating radar (GPR). While saturated hydraulic conductivities were estimated in a number of studies from GPR measurements, there are only a limited number of studies performed to determine soil hydraulic properties such as water retention curves using GPR measurements. In this paper, we mainly reviewed stepped-frequency-continuous-wave radar which can estimate soil hydraulic properties. Though its importance has been recognized for long time, no study has attempted to fully characterize the spatial distribution of soil hydraulic properties from GPR measurements. Since obtaining spatial distribution of soil hydraulic properties is an inter-disciplinary topic, we need to build a multi-disciplinary cooperative system for effective synergies among geophysicists, soil physicists, hydrologists, and geostatisticians to address current issues.
