Empirical Model for Backscattering at Millimeter-Wave Frequency by Bare Soil Subsurface With Varied Moisture Content

This letter presents results of the angular variation of millimeter-wave-radiation backscattering coefficient for various levels of soil moisture content. The research sets the basis for a method, which enables assessment of the soil-moisture content in the upper part of the shallow root zone. Further development of the method should provide a microprofile measurement of soil moisture up to the root zone depth. The method is based on the emerging technology of millimeter waves, providing improved spatial resolution of the subsurface concurrent with surface mapping. The development and the use of the method described herein will make it easier to analyze and understand processes governing the soil-water interface, such as soil crusting, infiltration, runoff, and soil erosion.