Answers are grounded in this paper and cite their sources.
A ground-penetrating radar (GPR) with a suspended horn antenna was used to obtain continual measurement of near-surface soil water content dynamics within a well-defined footprint. Water contents inferred from radar surface reflectivity (SR) were in agreement with gravimetric measurements from the top 1-cm soil layer. This sensitivity to top 1 cm was confirmed by comparison of SR with deeper measurements (1-5 cm) obtained by time-domain reflectometry. Measurements over sand and silt loam showed the role of soil type in controling near-surface dynamics of soil water due to evaporation and drainage processes. GPR with a horn antenna provided insights into physical processes that could affect larger scale radar platforms (air- or spaceborne) and enabled verification of radar measurements at well-defined spatial scales and detailed temporal resolutions not available by other radar remote sensing systems.
No takes yet. Share an insight, caveat, or question.
Serbin et al. (2004) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: