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Microwave back and forward scattering from a layer of vegetation continues to have important applications in remotely sensing soil moisture and vegetation biomass. Satellite radars detect backscattered returns while GNSS receivers can measure forward scatter. The scattering cross sections can be computed by the Distorted Born Approximation (DBA) and by 1st order transport theory. The first is a field...
The importance of antenna beam width in detecting enhanced backscatter in a layer of vegetation is studied. First, the vegetation is modeled as a layer of random media over a flat dielectric half space. The random media consists of thin dielectric discs and cylinders. The polarimetric bistatic scattering coefficients are calculated using the Distorted Born Approximation (DBA) taking into account scattering...
This paper traces the development vegetation modeling during the 1980's. In this time period, discrete random media methods were applied to model vegetation. The distorted Born approximation and transport theory were successfully employed to understand the different contributions to the backscattering cross section from a layer of vegetation. Leaves were modeled by thin dielectric discs and stems,...
A Fresnel double scattering (FDS) method is presented in this paper to accurately and efficiently calculate the scattering cross section from two tree branches not necessarily in the far field of each other at L-band frequencies. The branches, modeled as dielectric cylinders, are assumed to have lengths comparable to one or more wavelengths. It is demonstrated that the FDS method provides a good approximation...
A Fresnel Double Scattering (FDS) method is presented in this paper to accurately and efficiently calculate the backscattering cross sections from two tree branches in the Fresnel zone of each other. The branches have a comparable size to the wavelength for L band frequencies in length and in radius. It is demonstrated that the FDS results provide a good approximation to the exact solutions where...
Vegetation scattering problems in L band contain plant or tree components in the near field of each other. In this case, the interleaf or inter-branch interaction effect becomes more significant. In this paper, scattering properties from a cluster of plant or tree components are analyzed to study the interaction effect in the cluster. A numerical approach, the Discrete Dipole Approximation, is applied...
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