V. M. Artyushenko1, V. I. Volovach2
1 Technological University n. a. twice Hero of the Soviet Union, pilot-cosmonaut A.A. Leonova – a branch of the FSBEI HE «Moscow State University of Geodesy and Cartography» (Korolev, Moscow region, Russia)
2 Volga Region State University of Service (Tolyatti, Russia)
2 MIREA – Russian Technological University (Moscow, Russia)

1 artuschenko@mail.ru, 2 volovach.vi@mail.ru

Radio physical models are used to describe the relationships between scattering characteristics, thermal radiation and the geometry of the earth's surface, which take into account not only the effects of single, but also multiple scattering and shading. Considering the effects of secondary and multiple scattering allows reducing the characteristic methodological error in comparison with the approximate estimate at single scattering.

The possibilities of determining the radiation coefficient through the determination of the average energy flux passing through an uneven boundary and through the calculation of the bistatic scattering coefficient have been shown. It has been shown that in the Gaussian distribution of the tangent of the angle of inclination of surface irregularities, the observation angle, the dielectric constant of the medium and the dispersion of the tangent of the angle of inclination of random irregularities are used to describe the characteristics of scattering and radiation. In the second case of determining the radiation coefficient, instead of said dispersion, the corresponding probability density distribution is used. The effect of secondary and multiple scattering has been quantified. The relative value of energy corresponding to multiple scattering has been determined. A mechanism for taking into account the effect of reflected atmospheric radiation on the radiation of the natural cover has been shown. As a result, a radio physical model of surface radiation has been obtained, which makes it possible to take into account the effect of reflected radiation from a cloudless atmosphere and surface roughness on the characteristics of the thermal signal in the Kirchhoff approximation. It has been shown that an increase in the dispersion of the tangent of the angle of inclination of irregularities leads to a weakening of the polarization contrast in the thermal radiation of the surface. The error of calculation of the cover radiation factor in the single scattering approximation has been determined. The methodological error of the obtained radio physical model has been determined in specific cases by the relative role of multiple scattering effects. It has been determined that the equivalent atmospheric radiation temperature has a weak dependence not only on the roughness parameter, but also on the type of polarization of the received radiation. It has been noted that the effects of multiple scattering must be taken into account when the dispersion of the slope tangent exceeds unity.

The proposed radio physical model using multiple scattering and shading can be effectively used in the Kirchhoff approximation to describe the effect of reflected atmospheric radiation and surface roughness on the characteristics of thermal radio emission of natural covers.

Artyushenko V.M., Volovach V.I. Analysis of effect of the atmosphere and irregularities of the reflecting surface on the radiometric characteristics of natural covers. Antennas. 2025. № 5. P. 5–15. DOI: https://doi.org/10.18127/j03209601-202505-01 (in Russian)

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