ИСТИНА

Scattering of electromagnetic radiation in media, regular or random, provides important information on the structure and dynamical behavior of these media. Particular case of backscattering, i.e. scattering in the direction opposite to the direction of incidence, is of special importance for remote sensing applications because monostatic configuration of the experimental setup is very common in remote sensing experiments. For this reason, this type of scattering is extensively studied. Among physical effects, typical for backscattering in random media, it worth mentioning the weak localization, i.e. coherent backscattering enhancement effect. Under Twersky approximation, it is related to the backscattered intensity pattern of the pencil beam (searchlight), which can be evaluated with the radiative transfer theory. Present report summarizes some results of investigations of the backscattering of light in media with highly anisotropic phase scattering functions obtained during recent years. The backscattered intensity patterns of the pencil beams in these media have been extensively simulated numerically. The so called backscattering halo of the pencil beams, i.e. typical annular structure of the backscattered intensity pattern, was encountered in some cases. Asymptotic expressions of the backscattered radiation intensity have been derived and analyzed. Analytic criterion manifestation of the backscattering halo effects has been established and validated with Monte-Carlo simulation results. Dynamic backscattering halo observed in thin layers of scattering media, e.g. in lidar sensing of clouds , has been simulated by the finite-difference numerical solution of the vectorial radiative transfer equation (VRTE). Necessary conditions of the effect manifestation are studied.