Two semi-empirical models, simulating the backscattering coefficient from d
ifferent crops, were tested on the same wheat canopy. The physics of the se
mi-empirical models and the limitations of these models when scattering eff
ects are discussed. The results show that both models can be included in a
generalized formulation adapted to a large range of measurement conditions.
This conclusion confirms that the radar configuration (waveband, polarizat
ion, incidence angle) plays a role similar to that of the canopy structure
in the control of the radar backscattering coefficient.