CROP PARAMETER-ESTIMATION FROM GROUND-BASED X-BAND (3-CM WAVE) RADAR BACKSCATTERING DATA

The possibilities of crop parameter estimation from X-band radar backscattering measurements were investigated using empirical and simple physical relationships. The study used ground-based, multitemporal, multiangle, and copolarized radar data. The investigated crops were beet, potato, wheat, and barley. The investigated crop parameters were dry canopy biomass, amount of crop water, soil cover, and crop height. The implications of the results and recommendations for further research were discussed. Empirical relations and the "cloud" equations were inapt for accurate estimations of crop parameters from X-band radar data at one state of copolarization and one angle of incidence. The use of both vertical and horizontal copolarized radar data did not improve the estimation accuracy. The use of both a medium and a high angle of incidence improved the estimation accuracy of the amount of crop water in the early growing season of (only) beet. The use of more angles of incidence did not further improve the estimation accuracy. The low estimation accuracies were attributed to specific features of the X-band (early saturation, low soil-crop contrast), and to the simplicity of the mono / bivariate inversion schemes used.