Optimum Radar Parameters for Mapping Soil Moisture

Abstract

The radar response to soil moisture content was experimentally determined for each of three bare fields with considerably different surface roughnesses at eight frequencies in the 2-8 GHz band for HH and VV polarizations. Analysis of the data indicates that the effect of roughness on the radar backscattering coefficient can be minimized by proper choice of the radar parameters. If, in addition, sensitivity to soil moisture content and system design constraints are considered, the following radar parameters are recommended for an operational soil moisture mapper: Radar Signal Frequency: 4 GHz Angle of Incidence Range: 7°-15° from nadir Signal Polarization: HH or VV. The corresponding sensitivity is about 0.25 dB/.01 g/cm3.