Publicado 12 números por año
ISSN Imprimir: 0040-2508
ISSN En Línea: 1943-6009
Indexed in
Microwave Emissivity of Random Media with Vertical Structures
SINOPSIS
Microwave emission from random media characterized by long vertical structures, such as wheat and rice, was investigated using experimental data collected at 10 and 37 GHz (vertical and horizontal polarizations) on vegetation and on an artificial experimental model.
The influence of single plant constituents on the total emission from crops was evaluated by means of measurements carried out on plants in natural conditions and after sequential cutting of fruits, leaves, and stems. In addition, the effects of spatial distribution of the scattering elements were investigated using an experimental model composed of various distributions of long, thin vertical dielectric cylinders attached to a reflecting screen. It was found that, when the cylinders are distributed in nearly circular clusters or in parallel rows, significant emission enhancement with respect to uniform distribution is detected at 10 GHz and at incidence angles smaller than 50°. In contrast, at 37 GHz the emission is lower for clusters and strongly dependent on the azimuth angle for the "row" form. Finally, the dependence of the optical depth and single scattering albedo on the plant water content was estimated from the emissivity of wheat, using a radiative transfer model.