Polarization Structure of Multiply Scattered Background Components of Lidar Signals Reflected from Cloud Ice Crystals

A numerical experiment is performed to obtain the polarization characteristics of signals of a monostatic lidar intended for homogeneous cloud sensing. It is assumed that clouds consist of monodisperse randomly-oriented hexagonal ice crystals. To solve the vector radiative transfer equation, the light scattering phase matrices, preliminary calculated with the help of the beam splitting technique, are used as input data. The formation of the polarization structure of multiply scattered background signal component is studied for different scattering orders depending on crystal shapes and sizes and optical and geometrical conditions of the experiment.     

Acoustic Diagnostics of Laser Sparks in the Atmosphere

The results of an experimental study of the parameters of acoustic radiation generated by a laser spark made by focusing of a CO₂ high-power pulsed laser radiation outdoors in a slightly dusty atmosphere are presented. An analysis of the acoustic pulse spectrum shows that the position of its maximum is determined by the local plasma-formation radius, and the position of its low-frequency minimum is determined by the laser spark length. A new method of laser spark diagnostics in real time is suggested that enables one to estimate the plasma-formation size distribution function and the transmission factor for laser radiation propagated in the atmosphere under conditions of laser breakdown. The results obtained are in agreement with the available experimental data.     

On algorithms of the Monte-Carlo method for solving problems in the theory of propagation of narrow light beams. I

The characteristic features of the application of the Monte-Carlo method to one class of problems in atmospheric physics are discussed. Using an analysis of one of the programs in the most general form, we establish some characteristic features of the method of simulating radiation transport processes in narrow collimated light beams. An estimate is made of the advantages of semianalytic modifications of the Monte-Carlo method by comparison with direct simulation; and the results of test calculations are presented, confirming the feasibility of such modifications.     

Analysis of a stratified atmospheric aerosol model for the optical sounding wavelengths λ=0.6943, 1.06, 2.36, and 10.6 Μ

The vertical profiles of the aerosol attenuation and scattering coefficients are computed for the most prospective optical sounding wavelengths. The computations are carried out by exact formulas of Mie diffraction theory using experimental data about the microphysical nature of the continental aerosol.     

Algorithms for statistical modeling of radiation diffusion in a medium with a reflecting surface

An algorithm has been developed for calculating the transient propagation of a narrow collimated light beam in a scattering medium near a reflecting surface. The solution is applicable to a medium with an arbitrary scattering indicatrix and particle-size distribution. The angular reflection function and the albedo of the reflector are also arbitrary. Tabulated transmission functions are supplied, which allows the algorithm to be extended to the infrared region.We are indebted to G. V. Rozenberg and V. E. Zvev for proposing the topic.     

Synthesis, structure, and antioxidant activity of hybrid N-substituted salicylic acid amides

Sterically hindered phenols, 3-tert-butyl-N-(3,5-di-tert-butyl-4-hydroxyphenyl)-5-ethyl-2-hydroxybenzamide and N-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propyl]-2-hydroxybenzamide, were synthesized as potential antioxidants, and the formation of hydrogen bonds by their molecules was shown by UV and IR spectroscopy.