Measuring the propagation properties of a forest canopy using a polarimetric scatterometer

A truck-mounted 1.6-GHz polarimetric scatterometer was used from a 19-m high platform to measure the backscattering from a dense canopy of pine trees at an incidence angle of 40°. Two sets of measurements were made at each of many spatial locations, one set with and the other without a trihedral corner reflector present on the ground surface underneath the canopy. From the two sets of polarimetric measurements, it was possible to determine the mean values and the statistical distributions of the canopy attenuation factors for horizontal and vertical polarizations. The mean values of the one-way attenuation factors were found to be 9.31 dB for horizontal polarization and 9.16 dB for vertical polarization. The precision associated with the values of the canopy loss factor measured using the polarimetric technique is estimated to be on the order of ±0.3 dB