Modifications des modèles de diffusion pour une meilleure compréhension de la mesure radar sur les sols agricoles nus.

摘要

Radar remote sensing has shown great potential in the characterization of soil surface and hydrological processes. The knowledge of these parameters is of fundamental interest to quantify and predict the distribution of rainfall as well as modelling of the erosion of agricultural soils. Several models have been already developed but they still have limitations in understanding the behaviour of radar signal. The objective of this thesis is to provide improvements in backscattering modelling and description of agricultural bare soils using data from SAR and ground measurements. Using the analytical model of surface scattering IEM, we take into account a soil moisture profile by introducing a multi layered aspect. Taking into account constant moisture on the few centimetres of the surface is not realistic. We also take into account air pockets in the soil structure by redefining the dielectric constant and by introducing a compound air/ground. These developments allowed to improve IEM simulations and to better understand the behaviour of the radar signal and variations in the relationship between the backscattering coefficient and soil moisture. Finally, we perform a more realistic representation of agricultural soils including clods on the soil profiles. From an electromagnetic scattering numerical model based on the method of moments, we analyze the influence of these clods on the backscattering coefficient.