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vegetation with due regard for the electromagnetic properties of vegetative
elements to satisfy the needs in reliable assessment of vegetation impact
(screening effect of vegetation) on soil condition sensing;
developing methodologies of vegetation impact assessment in active (SAR) and
passive (MR) remote sensing of the Earth
s covers to reduce/eliminate/remove
the impact of vegetation on the land surface observation;
'
developing methodologies for assessing the impact of vegetation on the radio-
communication.
This project solved the following main tasks.
Building up of the measuring complex to conduct investigations of the atten-
uation of electromagnetic waves in vegetation covers and in plant elements
(leaves, sticks, etc.).
Systematization and generalization of the existing theoretical and experimental
data about attenuation of electromagnetic waves in vegetation.
Acquisition of experimental characteristics of electromagnetic waves attenuation
by various types of vegetative covers in the laboratory and
field conditions in
meter, decimeter and centimeter wavelength range.
Conducting model investigations of the attenuation of electromagnetic waves in
vegetation covers in meter, decimeter, and centimeter wavelength range.
Elaboration of methodologies for the screening effect of vegetation assessment
by conducting single wavelength measurements and by combining active and
passive methods.
Elaboration of methodologies for the screening effect assessment by conducting
multi-wavelength measurements and by combining active and passive remote
sensing systems.
Elaboration of methodologies for the screening effect of vegetation assessment
in radio communication.
Technical approach and methodology under the solution of these tasks were
founded on the following ideas. Theoretical part included utilization of the methods
of the radio waves propagation for the two basic types of vegetation models:
(1) vegetation in a form of inhomogeneous randomized media (stochastically
inhomogeneous or irregular), in particular to discuss the vegetation model as a
continuous medium with an effective value of dielectric permittivity; and
(2) vegetation as a community of discrete, separately located scatters; the deter-
mination of the attenuation cross-section of these elements.
In a continuous model, the vegetative cover was described as a homogeneous
medium with effective value of dielectric permittivity. The effective values of
permittivity were calculated in a quasi-static approach (the size of irregularities,
disks, needles, strips, is much less compared with a wavelength) by deriving dif-
ferent relationship based on the theory of dielectric mixtures. The corrections for
effective value of dielectric permittivity was made with due regard for the oscil-
lating (wavy) nature of the process.
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