Volumetric Effects in Cross-Polarized Airborne Radar Data

In recent years the detection of soil moisture using remote sensing technology has become of interest to investigators and a variety of state and federal government agencies. The parameter of interest is important in agricultural, meteorological, biological, and hydrological applications. The use of active microwave devices has shown to provide capability for remote measurement from space. Problems do exist however, in isolating moisture information from the effects of other parameters such as roughness and vegetation. Of special concern is the suppression of the roughness effects in the radar return. This paper presents an analysis of airborne cross-polarized radar measurements of agricultural scenes. The relative responses of the system to moisture and surface roughness are presented and compared to predicted responses using radar backscatter models. It is shown that the depolarized model predictions are sensitive to soil moisture, but are much less sensitive to surface roughness effects.