Application of GPR ground wave to monitor seasonal variations of surface moisture contents at a kanto loam field site

摘要

In the present study GPR ground wave was used to monitor the spatial distribution of surface moisture content at a kanto loam field site. To map the soil moisture variations at spatiotemporal scale, measurements were conducted on a regular interval of 2-3 days per week. To obtain more concise relation between the surface soil physical properties from the GPR, the study site was divided into two zones with and without vegetation to examine the influence of soil conditions respectively. Results revealed that GPR ground wave data were sensitive with the upper surface soil conditions as well as seasonal variations. Significant increase in dielectric constant, K, values was observed from the vegetated zone, while minor influence was found from the bare zone after a day after precipitation campaign. The cause of minor difference in the Zone-II was probably concerned with the percolation, runoff, evaporation, and the soil physical properties of the specific zone. Additionally, the depth influence based on Sperl (1999) and Pallavi et al. (2009) was found most accurate among other depth models. The above study signifies that the GPR ground wave can be used as a principal tool for spatial mapping of moisture content with the known sampling volume for Kanto loam.