R.P. Bystrov, E.A. Zasovin, A.V. Sokolov, S.A. Sokolov

It is known that submillimeter (SBMW), millimeter (MMW), centimetric (SMW) and decimeter (DMW) waves have oscillations in receiving amplitude of a signal in radar and transmitting applications in aerosphere which are known as fading. Basically such fadings essentially worsen the operation of various radio systems depending on conditions in aerosphere, distribution of refraction index of air and its temporal and space oscillations. Reasons of similar fadings in aerosphere are rather numerous, and they are studied, as a rule, statistically. The prime problem - to collect enough statistic at reception of various signals in different wavelengths taking into account singularities of aerosphere-s structure, various metrological conditions, daytime and season, and also effect by hydrometeors and aerosols. The research of fadings of the signals spreading on short routes appears slow oscillations of received signals due to convective space and temporal total-absorption fluctuations. One should be noted that fractal rotational fadings have been investigated in detail with American mathematician Mandelbrot. Thus it has given a statistical treatment of the random fractals, obeying the Gaussian law. This phenomena is named as fractal Brownian motion (FBM) with a statistical self-similarity [1]. Recently Lee and Waterman have shown convincingly [2] that V.I. Tatarsky theory [3] can describe fadings on MM and SM waves as well as that of optical radiation. Assuming the absence of strata of inversions and considering that the frequency spectrum of fluctuations of refraction index of air is proportional to f5/3, it is possible to sign the following expressions for definition of the logarithm of amplitude of fadings on the routes located along terrestrial surface at altitudes of some tens of meters: Random fadings of signals which Gaussian spectra diminish in extent 8/3 are investigated. The convective transpositions of air masses from a modification of intensity of non-fractal radio signals which correspond to regular inhomogeneous refraction of radio waves are investigated. Daily and seasonal types of fadings, and also appearances of super-refraction, subrefractions and fluctuations of an antenna pattern direction are established. The refraction errors are estimated in geometric optics approximation.