Retrieval of the effective soil moisture contents as a ground truth from natural soil surfaces

摘要

A method for retrieving effective soil moisture contents from natural soil surfaces is proposed. Natural soil surfaces usually have various types of soil moisture depth profiles. The transmission and reflection coefficients of the homogeneous soil surfaces were examined. The backscatter from a two-layered rough surface was also examined. From those examinations, it can be concluded that only the top 0-1 cm layer of soil surfaces influence the backscatter even for an extremely dry surface, and the effective soil moisture can be obtained from the 1 cm surface layer for L-band, and the top surface layer for C- and X-band frequencies.