Applying polarimetric radar imagery for mapping the productivity of wheat crops

Abstract

Airborne, fully polarimetric C-band radar imagery was acquired over an agricultural test site located in southern Ontario (Canada) on 30 June 1999. Approximately 2 weeks after this image acquisition, yield-monitor data were collected over two wheat fields. Zones of higher productivity had higher radar backscatter, for linear (HH, VV, HV) and circular (RR, LR) polarizations. Zones of productivity were classified using backscatter from the linear polarizations, and these classified maps agreed well with the maps generated by the yield monitors. The linear cross-polarization (HV) provided the greatest contrast between zones of high and low productivity, although the height of the cross-polarization pedestal also varied between these two classes. No significant differences were observed between high- and low-producing zones using either the copolarization pedestal height or the copolarization phase difference. This study demonstrated that polarimetric radar parameters such as the linear and circular polarizations and the cross-polarization pedestal height are sensitive to differences in wheat productivity.