Method of obtaining global digital maps of underlying surface electric characteristics in the very low frequency band
The conductivity and dielectric permittivity of the underlying surface are part of the initial data necessary for calculating the energy parameters of radio tracks. The lack of complete information about the electrical characteristics of the Earth surface indicates the relevance of the researches. The technique of forming global digital maps of the electrical characteristics of the underlying surface in the very low frequency range points to two main aspects: the formation of information about the electrical characteristics of the continental and oceanic parts of the Earth surface. We obtained the global conductivity map of the continental part of the Earth surface by digitizing the soil conductivity atlas. We calculated a regression function, on the base of which a global map of the dielectric permittivity of the soil has been formed. Using the methods described in the ITU recommendations, we obtained global maps of the conductivity and permittivity of the oceanic part of the Earth surface based on data of the temperature and salinity of the world ocean. With the help of the developed data consolidation algorithm, we transformed the intermediate results into global digital maps of electrical characteristics of the Earth surface in the very low frequency range.