Influence of vegetable cover on propagation of...

Conclusion

[38] 1. The influence of the vegetable cover on propagation of electromagnetic waves in the Earth-ionosphere wave channel may be taken into account in the model of a homogeneous isotropic "forest layer" with the effective value of the dielectric permeability e_f=1.2 and electric conductivity s_f (t ^oC) depending on the environmental temperature according to the curve shown in Figure 2.

[39] 2. The character of the electromagnetic field behavior at the presence of large forests is of a well-pronounced seasonal character additionally complicated by the diurnal variations of the field depending on the environmental temperature variations.

[40] 3. The modulus of the attenuation function of forest paths at some distances from the emitter is higher than unity because of the influence of the Zennek surface wave.