This PDF file contains the front matter associated with SPIE Proceedings Volume 11208, including the Title Page, Copyright information, Table of Contents, Author and Conference Committee lists.

We use a deterministic approach to simulate summer hydrothermal regime of a stream. Our simple model involves calculating water temperature in a coordinate system moving with the water. The physically based estimation of water heat budget takes into account absorption of solar radiation by water surface, emission of thermal infrared radiation (TIR) by water and absorption of atmospheric TIR, as well as convective heating of water and heat loss due to evaporative processes. The proposed model is applied to simulate stable diurnal thermal regime of the Yenisei River, employing the Fourier equation for mathematical modeling. We assess the contribution of each of the physical processes into water temperature and come up with a stable temporal diurnal thermal regime for the Yenisei River.

The paper presents the results of 2D numerical simulations with a magnetohydrodynamic model "shallow water" which was used to estimate the influence of magnetic field on increments of instabilities in the tachocline caused by anomalies of the mean flow. Calculations confirmed the previously obtained result about the strong influence of anomalies of the mean flow on the instabilities of the differential rotation. Average magnetic field of relatively small magnitude stabilized development instabilities, but when it reaches a critical value, stabilization stopped and typical time of instabilities development sharply decreased. Also instabilities significantly well depended on amplitudes of initial perturbation velocity field and the magnetic field.

The main components of the synthesis gas are hydrogen, carbon monoxide, methane and carbon dioxide. In this work, we studied the spectral characteristics of the most intensive Raman bands of these components as a function of environment at a fixed pressure of 25 bar. It has been established that, under these conditions, the change in the characteristics of pure rotational hydrogen lines is negligible, and the vibrational bands of methane, carbon monoxide and carbon dioxide shift to a few tenths of cm^–1. The data obtained allow to improve the accuracy of determining the composition of the synthesis gas using Raman spectroscopy.

The effect of methane environment and increased pressure (up to 25 bar) on the stability of the conformational equilibrium of gaseous n-butane was investigated using Raman spectroscopy. It is established that under these conditions the change in the concentration of trans and gauche-conformers of n-butane is less than 1%. The results obtained will be useful for Raman diagnostics of natural gas composition.

The upward and downward fluxes of longwave radiation are simulated for the atmospheric conditions observed in summer and winter in Lower Volga region. The discrepancies in the longwave fluxes in the radiative block of the RegCM climatic model due to use of different water vapor continuum models are estimated. The continuum models used in NCAR CCM3 and RRTM radiation schemes in the regional climate model RegCM 4.5 are considered.

We applied the method of statistical trials to the parabolic equation of laser radiation propagation in biotissue to perform a new method of optical coherence tomography modeling. Results of modeling tests show the efficiency of the developed approach.

The complete collection of published spectral line parameters of aluminum hydride and deuteride molecules in W@DIS and its parts are described. About 35 information sourses were created and about 60 papers were collected.

In this paper, various designs of non-resonant photoacoustic cells with a different arrangement of microphones are investigated. It is demonstrated that it is possible to expand the dynamic range of measurement of gas concentration using the special configuration of cell cavities and the specific location of the microphone. The suppression of resonant acoustic effects occurring in the measuring photoacoustic cell is characteristic of this cell cavity design. Given this suppression, only the primary sound wave affects the microphone diaphragm. The implementation of a new cell design allows us to extend the range of measurement of SF6 gas impurity concentration in the atmosphere from 100 - 1000 ppm up to 10 - 10,000 ppm.

The results of a comparative study of an emanation from the skin of patients with diabetes mellitus and healthy volunteers using THz spectroscopy. A technique for collecting and analyzing emanation samples from the skin has been developed, and its applicability in THz spectroscopy has been demonstrated. Good separation of THz spectra of the skin emanations has been shown for the target and control groups by the principal component analysis. It shows that THz spectroscopy of skin emanations is useful for the diagnosis of diabetes mellitus.

A software module, enabling approximate calculation of spectral atmospheric transmission coefficients within the wavelength range from near-ultraviolet to near-infrared emission, was developed. The present module provides computational and informational support for computer modeling process of optoelectronic systems (first of all, for geodetic purposes) when amount of source data on atmospheric conditions anticipated in modeling is limited. Principal mathematics taken as a basis of the model are specified.

The quasi-static compression optical coherence elastography (OCE) is used to find Young’s modulus of human skin^1,2 . The data on the layers of human skin deformation in vivo were obtained and analyzed. In the OCE compression method, a calibration layer with a known Young's modulus was used, which made it possible to identify the value of the volunteers' skin elastic modulus.

The results of the comparative analysis of exhaled air samples from patients with diabetes mellitus second type (target group) and healthy volunteers (control group) with using laser optical-acoustic IR spectroscopy are presented. The measured absorption spectra of exhaled air samples visualization were performed using the principal component analysis. The good spatial separation of the target and control groups in the space of the main components was achieved, which indicates a significant change in the composition and concentration of metabolites in the exhaled air of patients with diabetes. The volatile metabolites that may be characteristic of diabetes are also discussed.

Methods of two-photon microscopy are widely used in the study of biological objects, in particular, skin, due to the possibility to study objects both on the surface and at depth without attracting additional fluorophores due to endogenous autofluorescence. In this paper, the methods of image analysis of the AF signal and SHG signal are applied to assess the condition of the skin during the development of lymphedema. It is shown that for groups of healthy tissue and lymphedematous using SAAID distribution histograms, changes in tissues can be detected.

A model of lymphedema was developed using laboratory animals. During lymphatic edema enhancement, a study was made of changes in the structure of biological tissues by interference optical methods in the near infrared region of the spectrum. Statistical methods were applied for describing textures of the experimental images of the affected tissues, informative features of the dynamics of fibrosis development were identified.

The results of studies of exosome visualization obtained using multiphoton fluorescence spectroscopy for healthy volunteers and patients with colorectal cancer are presented. Standard centrifuging technology was used to isolate exosomes from blood plasma. Exosome samples were investigated using the femtosecond laser pumping at the wavelength of 760 nm with and without FITC (Fluorescein isothiocyanate) labels. In particular, the exosomes with CD9 surface glycoprotein of the tetraspanin family was shown to be studied without labeling using FLIM (fluorescent lifetime microscopy).

The paper presents the results of experimental studies of the influence of the level of tonal acoustic noise on the times of simple human reactions, such as a simple auditory-motor reaction, a simple visual-motor reaction, a simple tactile-motor reaction, as well as a detection reaction. Experimental studies have shown that during the action of tonal acoustic noise with a frequency of 100 Hz, the subjects experienced an increase in the times of all the simple reactions being analyzed. The effect of tonal noise with a frequency of 100 Hz on the detection response is less pronounced.

During analyzing of geophysical data, the problem of highlighting a form of geophysical signals often appears. In this work, it is proposed to use deep learning, which is currently one of the top priorities in the field of artificial intelligence and machine learning. The samples of geophysical signals, as well as the generated samples of signals by their mathematical models and typical examples of forms, act as a training dataset for deep neural network. End-to-end demonstration examples of the highlighting of reflection traces from different layers of the ionosphere in the ionograms, as well as the highlighting of whistler forms in the VLF spectrograms are presented.

Small sets of chemical kinetics equations describing the cluster formation of complexes in water vapor are investigated. Sets of equations for N≤10 are solved by means of the implicit Eulerian method of the first order of accuracy for the model systems with unit rate constants and with real rate constants available in the literature. The character of cluster concentration distribution in the steady state as a function of their dimensions is changed at variations of the total monomer number A.

An effect of the implementation of the new aerosol-cloud-radiation interaction scheme in the COSMO model is described. The results of simulations with the new scheme are given for various values of the aerosol concentration. The aerosol effect on the forecast of cloud microphysical characteristics and radiative fluxes was determined. The study conducted for Meteorological Observatory of Moscow State University for a warm period (April – October) 2018. Values of integral cloud water/ice content obtained in experiments with fixed cloud nuclei concentration were noticeably smaller than in experiment with aerosol climatological data. Simulations shown the decreasing of global radiation with increasing cloud particle number that is connected with increasing of the concentration of cloud nuclei. We obtain better results against observations when cloud nuclei concentration is set according to Tegen aerosol climatology compare to fixed concentration.

We study the annual cycle and interannual variability of the intensity of outgoing longwave radiation (OLR) in Western Siberia region for the period 2003-2018 as observed by AIRS/Aqua. It is established that the OLR intensity anomalies rate of change in the study period varies from -0.30 W/(m² year) and +0.14 W/(m² year) for the cloudy atmosphere and from -0.23 W/(m² year) to +0.17 W/(m² year) – for the cloudless one. Simultaneous analysis of the OLR data and the surface temperature and water vapor distributions showed that the variation of OLR in 2003-2018 in Western Siberia was mainly caused by changes in surface temperature.

We consider the simulation system for modeling the AIRS/Aqua channels readings. The key element of the system is the Line-By-Line Radiative Transfer Model (LBLRTM), which allows to calculate the intensity of the outgoing radiation with high spectral resolution (up to 0.001 cm^-1). The results of simulations of the IR atmospheric sounder AIRS/Aqua readings for nighttime cloudless AIRS pixels in the area of the Atlantic Ocean are presented. Verification of the simulation system has been performed. Also we discuss the results of the “tuning” procedure designed to exclude systematic errors associated with an uncertainty of setting the optical and thermodynamic properties of the atmosphere.

The methane absorption spectra in the range between 6600 and 9200 cm^-1 have been recorded at 296 K and 109 K by the Fourier spectrometer IFS – 125M at pressures from 11 to 300 mbar, and spectral resolution 0.03 cm^-1. Low temperature cell with a length of 220 cm was used, which provided the threshold sensitivity to absorption of the order of 10^-7 cm^-1. Empirical values of the lower state energy level were derived from the intensity ratios of the lines measured at 200 K and 296 K. Line assignment of the the 3ν₃ band of the ¹²CH₄ molecule was performed. The parameters of Voigt, SDV, HTP contours (the line center, intensity) were determined at 296K.

Air pressure induced broadening and shift coefficients for methane absorption lines in the 6000–6100 cm^–1 region have been measured. The spectra were recorded using Bruker IFS 125 HR spectrometer at room temperature, at the spectral resolution of 0.01 and 0.007 cm^–1 and in a wide pressure range of air. The multispectrum fittings with the quadratic speed dependent Voigt profile were performed to retrieve the broadening parameters for CH₄ spectral lines. The atmospheric transmission of CH4 calculated by line-by-line method with use of absorption lines parameters from different spectroscopic databases and data obtained in this work was compared.

An approach is presented which allows visual and quantitative trust assessment of composite multi-paper plots, where the results of the graphical representation of calculation or measurement results from different publications are compared. Using plots from the W@DIS IS collection, which characterize the continuum absorption, as an example, we show the procedure of construction of a composite multi-paper plot.

A mechanism of excitation of the CO₂ vibrational states due to E-V energy transfer through a chain O(¹D) → (N₂(v), v=1−5 and O₂(v), v=1−4) ↔ CO₂(v₃) was updated in the non-LTE model for the CO₂ infrared emissions in the Earth atmosphere. It was found that including this mechanism results in significant increase of populating the excited vibrational states of N₂, O₂ and CO₂ followed by significant increase of cooling rate due to transfer of radiation in the CO₂ bands in the altitude region of 90-110 km. Main inferences are as follows. For noon conditions at the equator for spring equinox under average level of solar activity (F_10.7=90), about 23-25 per cent of flux of solar UV energy, which spent to excitation the O(¹D) state after photodissociation of ozone and molecular oxygen, transfers to both N₂(v) and O₂(v) vibrational states due to E-V energy exchange during collisions. After that, a part of this flux transfers to the CO₂(v₃) states due to intermolecular V-V energy exchange. Finally, the energy is radiated from the atmosphere mainly in the 4.3μm fundamental band of the CO₂ principal isotope with an efficiency of 0.9, 0.87, 0.82, 0.6, and 0.25 at the altitudes of 90, 95, 100, 105, and 110 km, respectively. This provides an additional cooling of the MLT region with a maximum rate of order 6.0 K/day at 105 km. Such an estimation is more larger than it had been obtained in previous investigations. So, comparing to the most recent estimations of the 15 μm CO₂ band cooling rate, this seems to be a valuable additional source of cooling of the lower thermosphere comparing to the most recent estimations of the 15 μm CO₂ band cooling rate.

Results of theoretical and experimental investigations into problems of underwater optical communication on scattered laser radiation in the Siberian Branch of the Russian Academy of Sciences (SB RAS) are discussed. Theoretical investigations of bistatic communication channels are carried out by statistical simulation of the process of signal propagation from a source to a receiver by the Monte Carlo method. Experiments were carried out under field conditions with different characteristics of radiation sources and receivers, orientations of their optical axes, and immersion depths in water. Ranges of action, probabilities of communication errors, and their SD estimated for winter and spring-and-summer seasons are presented.

We report the numerical simulation results obtained using a two-frequency coherence function in the double-weighted Fourier transform approximation. We perform the simulation for different models of inhomogeneous media.

The approximating dependencies for the spatial characteristics of the intensity distribution of the wave beam in the registration plane are proposed. Was formulated algorithms for control the rotation of a profile without changing its structure, allowable tensile and compression deformities along selected directions. A three component multiplicative form for the ABCD matrix of the optical system-converter of the wave beam profile is discussed.

We have considered the problems of full-view matrix recorders of signals and energy wave beams for telecommunications, remote sensing and wireless energy transfer. The results of an experimental study of the temperature field being formed when working with sources of continuous coherent radiation of high power, inhomogeneous thermal degradation of the integral efficiency of the converter has been presented. We have also studied the influence of the energy-carrying beam form factor on the structure of the recorded signal and the efficiency of photoconversion. The problems of the thermal response of the photoconverting matrix have been considered when working on the borders of the quantum yield band of silicon photoconverters.

Results of numerical simulation of light absorption by the dimer of bilayer spherical particles consisting of a water core and a polymer shell absorbing radiation are presented. The spatial distribution and the amplitude characteristics of the volume density of the absorbed power are investigated. It is shown that for a certain spatial dimer configuration, the maximal achievable density of the absorbed power is realized. It is also established that for closely spaced microcapsules with high shell absorption indices, the total power absorbed in the dimer volume can increase in comparison with the radiation absorption by two insulated microparticles

The problem of reconstruction of the Earth surface reflection coefficients from satellite data with allowance for radiation polarization is considered. Previously it was shown that in the process of atmospheric correction, optical-geometrical conditions may arise under which the allowance for radiation polarization is essential. In the present paper, the program complex for atmospheric correction of satellite images has been developed that takes into account radiation polarization. It has been used to process the Earth surface images recorded by the MODIS device.

The long-term observations of day and night stratification of the atmosphere in the Sayan Solar Observatory (Mondy settlement, Buryatia) were continued. A new mobile hardware-software ultrasonic complex AMK-03-4 designed to measure the characteristics of turbulent meteorological fields was used for measurements. New experimental data for turbulent scales of velocity V* (friction velocity) and temperature T*, which are important characteristics of turbulence in the Monin-Obukhov similarity theory, are presented. Comparison of the experimental results with the data obtained by the authors earlier in different times in various climatic and geographical regions is carried out.

The temporal error of the adaptive optical system leads to a significant degradations in the characteristics of the system operating in the atmosphere. One of the methods for solving this problem is the use of prediction algorithms based on the analysis of the evolution of phase fluctuations. In the paper the wavefront sensor as the key element of atmospheric adaptive optical system with predictions algorithms is considered. The results of the development and testing of the Shack-Hartmann wavefront sensor providing measurements of phase fluctuations, determination of the Fried parameter and wind speed using original design solutions and software are presented. The practical and theoretical aspects of using the Shack-Harmann wavefront sensor are discussed. For it dynamic range, sensitivity and accuracy of the sensor are estimated. The influences of parameters of microlens array on range of measurements of the Shack-Harmann wavefront sensor are studied. The tests of the S-H WFS were carry out with acoustic measurements of wind speed and the structural constant of the refractive index of the atmosphere, as well as in adaptive optics system in laboratory test bench.

The optical element in the Shack-Hartman wavefront sensor is a microlens raster, which breaks the light field with phase distortions in the approximation of geometric optics into partial beams. The phase fluctuations of the light field within the sub-aperture correspond to the fluctuations of two angles of arrival or the fluctuations of two local inclinations of the wave front within the same limits of the sub-aperture and are associated with correlation relations. In this case, the correlation is a quantitative measure of the "similarity" of the two corresponding phase distributions within the subaperture on the two analyzed Shack-Hartmann patterns. The paper presents the results of numerical experiments on the reconstruction of the wave front using the correlation approach to the centering of focal spots.

The Hartmann-type wavefront sensor consists of two parts: optical and algorithmic. The parameters of the elements of the optical part of the sensor can vary. The results of the analysis of wavefront reconstruction from sensor measurements are presented depending on the configuration of the sub-apertures of the lens raster included in the reconstruction and on the intensity of turbulent distortions of the light field coming to the input aperture of the adaptive system. The analysis was performed on numerical models of the Shack-Hartman wavefront sensor, atmospheric turbulence, and a lens raster with an arbitrary configuration of subapertures included in the wave front reconstruction.

It are evaluated characteristics of an simulation stand on adaptive optics. The stand is created on the basis of LCAO IOA SB RAS in order to work out algorithms for adaptive correction, research and testing of measuring equipment. The stand allows generating turbulence with given parameters for a particular flexible mirror. In this case, a wave front with different turbulent inhomogeneities with varying their intensity is formed, and the wind transfer of inhomogeneities in the plane of the entrance aperture of the system is also set. For the deflector [1] included in the stand scheme, the tilt angles of the optical radiation are programmed. The Shack-Hartman wavefront sensor and, in parallel with it, a split photodetector measure the characteristics of the incoming optical radiation, which are compared with given parameters. The flexible mirror and deflector reproduce turbulence with given parameters and slopes, respectively.

The paper considers various technologies of alignment of rotary kilns in their operation mode. It gives the theory of mathematical processing of rotary machines measurements with the help of electromagnetic emission and the influence of refraction onto their accuracy. The research showed that the technology of measuring along the kiln shell can contain significant errors, caused by refraction in horizontal section due to big temperature gradients. The technology, when the observing beam goes perpendicular to the kiln shell, is practically unresponsive to the influence of refraction. The paper considers the tasks, which demand further research and refinement.

Using a combination of the Fock proper-time method and the double weighted Fourier transform, we have derived a solution of the problem of wave reflection from a regularly inhomogeneous layer with random irregularities. The report uses this solution to determine the mean field and the frequency coherence function. The condition of applicability of the geometrical optics approximation for the frequency coherence function in the narrowband case is much weaker than that for individual realizations. We report the simulation results for the Gaussian spectrum of irregularities and for Shkarofsky's model.

Using the developed algorithm of the Monte-Carlo method with modified double local estimation, the impulse response of the link of non-line-of-site underwater communication on scattered radiation is simulated for base distances between the source and the receiver from 10 to 100 m. The quality characteristics of the communication link, including the received radiation power and the maximal repetition frequency of pulses transmitted through the communication link, are estimated based on the impulse response characteristics calculated for the transceiving system at a wavelength of 0.5 μm.

The Shaсk-Hartmann wave front sensor measures the coordinates of the energy centers of gravity of the focal spots located in the plane of the receiving device in the form of the Hartmann pattern. The Hartmann pattern can be definite and not fully defined, i.e. on it there can be no separate focal stains or groups of focal spots. The information extracted from such Hartmann patterns change significantly the result of the wave front reconstruction. This suggests also the creation of a modification of the previously developed correlation algorithm for calculating the speed of transverse wind transfer of the turbulence. The results of numerical studies are presented.

The atmospheric channel of optical non-line-of-site communication is considered. Minimal ratio of the source power to the maximal sensitivity of the receiving system is estimated at which communication is still possible.

In this paper, using the numerical simulation, we investigated the possibility of compensating aberration wavefront distortions caused by aero-optical effects on the aircraft-satellite paths using the backscatter signal in the atmosphere. It is shown that phase distortion is compensated and the intensity distribution of the laser beam becomes symmetric about the optical axis.

Formation of ice particles of noctilucent clouds is discussed. These ice particles are supposed to contain ice 0, the recently discovered ferroelectric modification of ice. At the contact of ice 0 with the surface of a dust particle, there emerges a thin layer having high electric conductivity, which accounts for intensive scattering of electromagnetic radiation in the broad band of frequencies. Another mechanism is suggested for emergence of water in the mesosphere due to reaction of interaction between hydroxyl molecular groups on the surface of a silicate particle and molecules of gaseous hydrogen. It is proposed to make observations over noctilucent clouds by employing the methods of microwave radiometry.

The paper presents an optical model of a shock wave, which is formed by supersonic air flow around a body of an aerodynamic shape. The mean values of the flow parameters were calculated using the CFD Fluent 6.0 software package, taking into account the compressibility of the gas. The results of numerical simulation of the propagation of an optical beam transmitted through a shock wave at the beginning of the path and then propagating in a homogeneous medium and a turbulent atmosphere under various turbulent conditions of light propagation are presented.

An algorithm is proposed for the fast Fresnel transform, for problems of propagation of an electromagnetic signal in free space, suitable for both modeling FSO problems of optical communication technology and holography. The algorithm is based on reducing the number of repetitive computations of the elements of the transform kernel based on the use of different types of symmetries when calculating the corresponding transform kernels. It is shown that the proportion of unique Fresnel transform kernels is much less than the total number and even less than in the Fourier transform.

The article discusses various methods of image quality assessment. A comparative analysis of sharpness functions as a measure of image quality, in the absence of a standard for comparison, was conducted.

Possibilities of remote detecting of laser beams, propagating in the scattering atmosphere, are considered.
The field studies show that, for chosen conditions of measurements and types of laser beams, the contrast of brightness depends strongly on beam type.

In this work, we present the directions of further development of a prototype of television navigation system (TNS) for course setting in precision orientation of vehicles during their motion guided by the video and audio information transmitted via radio channel to the receiving onboard instrumentation.
We discuss the issues of precision of TNS-guided course setting and possibilities for TNS and GLONASS/GPS system coupling using digital navigation maps with the ship coordinate determination simultaneously in two independent channels, thus making the ship navigation much more reliable and safe. A key salient feature of TNS is that the ship can be navigated within the line of sight at distances as long as 20 km at up to 1-m SD of cross-track deviation from preset course, and those observations are ensured under the conditions of degraded visibility in the atmosphere.
Capabilities of “Vzlet” TNS are explored for aircraft taxiing, take-off, and landing on the basis of preliminary flight tests. Other potential TNS applications are discussed.

To restore the height profiles of the atmospheric turbulence we used the analysis of the spatial crosscorrelation functions of wavefront distortions registered by the Shack-Hartmann sensor of the adaptive optics (AO) system of Large solar vacuum telescope. In the paper the results of analysis of spatial crosscorrelation function within the field of view ~35 arcsec are discussed. It is shown that the wavefront distortions formed within the field of view ~35 arcsec are not random. There are the repetitive hills of spatial crosscorrelation functions in the field of view at the same intervals for different space subapertures. It is shown that spatial crosscorrelation functions do not contain pronounced kernel for finding the exact position of the atmospheric layer contributing to significant distortions in the wavefront incident on the telescope aperture.

Results of numerical simulation of a vortex laser beam propagation reflected by a flat mirror at different intensity of optical turbulence in the atmospheric are presented. The relative variance of fluctuations of mean intensity in the cross section of the beam is analyzed. It is found that the strength of the optical turbulence increase, the fluctuations of mean intensity to the edge of the beam decrease for the reflected beam than that for the beam having pass double distance in the direct path.

In numerical and field experiments, a wind profiling algorithm based on analysis of a mutual correlation of turbulent fluctuations of the energy centroids of binocular video images of remote incoherent sources was tested. It is shown that by selecting the configuration of the relative position of sources and receiver lenses it is possible to achieve the formation of a stable correlation function with a maximum shifted relative to zero delay. The magnitude and direction of the shift are consistent with the velocity and direction of the turbulent flow in the corresponding part of the optical path.

Theoretical research of coherent properties of the vortex conic waves propagating in turbulent atmosphere is developed. For the analysis of the analytical solution of the equation for the transverse second-order mutual coherence function of a field of optical radiation was used. The coherence radius, the normalized root-mean-square and the integral scales of a coherence degree of the vortex conic waves were considered, their dependence on parameters of optical radiation and turbulent atmosphere is analyzed. In particular, with increase in a topological charge the value of integral scale of coherence degree of a vortex conic wave beam are decreased. Preference of use for the adaptive optical systems compensating distortions of pseudo-Bessel beams in turbulent atmosphere as the gauge of distortions not a coherence radius measuring instrument such beam and a measuring instrument of integral scale of coherence degree is proved.

Properties of vortex radiation are discussed in the article using the data obtained by the authors and information found in references. Possible applications of such radiation are considered. Special attention is devoted to the methods of vortex registration. Precision of two registration algorithms is compared and particularities of their practical realization are analyzed.

Two possible methods to solve scalar parabolic wave equation describing beam propagation in a randomly inhomogeneous medium have been compared in the article. The analytical approach was based on additive approximation, while numerically the equation was solved by the split-step Fourier algorithm. As was shown calculation of the beam radius with the use of both methods provides approximately the same results in the interval of weak fluctuations of the index of refraction. Increase of distortion intensity leads to divergence of data obtained analytically and in computer simulations. This disagreement can be explained by intrinsic limitations of additive approximation evolving in the regime of strong amplitude-phase fluctuations.

A statistical analysis of profiles from 0 to 70 meters of potential temperature and main bio-optical characteristics of the Black Sea was performed: chlorophyll a concentration, particle backscattering coefficient at 700 nm, the concentration of the colored component of dissolved organic matter, obtained as a result of long-term measurements from three bio-argo floats. The analysis made it possible to describe the profiles of the above parameters, as well as their dynamics during the year. In comparison with the obtained profiles previously used in the model, calculations showed their higher accuracy. The last made it possible, in conjunction with satellite, measurements more accurately restore the vertical structure of the bio-optical characteristics of the upper layer of the Black Sea from September 1997 to December 2018.

The results of a numerical analysis of the manifestation of the backscatter amplification effect in the regime of weak optical turbulence in dependence on diffractive size of the transmitting aperture are presented. It is shown that the magnitude and localization of the amplification of the average power of the radiation back scattered in a turbulent atmosphere depends on the Fresnel number of the transmitting aperture. Since the Fresnel number changes with changes in the distance from which the lidar signal arrives, this must be taken into account when profiling the intensity of optical turbulence from the lidar data on the amplification of the average power of scattered radiation.

This paper analyses conditions of flame stabilization in a channel with moderate swirling of a flow and low Reynolds numbers. The effect of swirling on the flame structure and localization of the combustion zone is investigated, and the conditions for flameout in flows with a moderate swirling flow are determined.

The work is devoted to the development of an algorithm describing the nature of the interaction of directed optical radiation with an optically transparent object of spherical shape – a raindrop. To solve this problem, in the approximation of geometric optics, the relations describing the angular nature of the radiation propagation in the droplet for four reflections from the interface of the two environments under consideration were obtained: air-water. Further, on this basis, the relations were obtained to describe the nature of the angular propagation of radiation outside the droplet for the four interaction points. As a result, the obtained relations were used to obtain digital data on the extreme values of the angles of the two functions: Ψ and φ . These values coincided with the angles of the primary and secondary rainbows formed by the interaction of directed optical radiation with a raindrop. Thus, the correctness of the developed algorithm describing the interaction of directed optical radiation with a raindrop is confirmed. This fact allows the estimation of the parameters of interaction of optical radiation with different values of refractive index, i.e., for other environments.

In this paper we consider the influence of various parametrizations of aerosol-cloud-interaction on the total solar radiation and cloud transmission at the earth's surface according to the INMCM5 model. Several 10-year numerical experiments were carried out with/without three parametrizations of this interaction. In addition, numerical experiments with different emissions of aerosol precursor gases for 1980 and 2005 were performed. We show that the account for aerosol particles in aerosol-cloud interaction leads to an increase in the cloudiness by an average of 0.1 and a decrease in the total radiation by 25 W/m². As a result, there is a decrease in the air temperature by an average of 2 degrees for all months of the year. This result confirms the theoretical assumptions about the increase of the cloud albedo effect with a decrease in the effective radius of the particles. However, numerical experiments with different emissions of aerosol precursor gases for 2005 and for 1980 revealed that at lower emissions there is a decrease in cloud transmission and an increase in the cloudiness. The probable causes of the observed effect are discussed.

Calculated and experimental studies of the amplitude-time and spectroscopic characteristics of an IR parametric laser based on mercury thiogallate with wavelength tuning in the range 5-9 μm were carried out. The possibility of achieving the maximum energy output up to 5 mJ per pulse with an extremely narrow spectral width of the radiation (≤ 0.5 cm-1) is shown.

The method of laser IR radiation propagation simulation in a case of randomly inhomogeneous media based on Leontovich – Fock equation in the application of optical coherent tomography modeling in biotissues is proposed. We describe the proposed methodology and demonstrate its implementation on a test case.

The numerical simulation results of coal slurry fuel (CWS) combustion in a swirling-type furnace are presented. The velocity and temperature distribution in various sections of the furnace are obtained, as well as the trajectory of the fuel particles movement and its burnout time.

The paper presents the experimental study results on the effect of heat flux emitted by a standard source on the charring and ignition characteristics of pine wood. Using a new method of setting the experiment with the recording of IR image, the charring rate and depth of the wood as a result of heat exposure from a standard source. The influence of several fire retardants on the charring rate and depth of samples is analysed. The use of noncontact IR diagnostics allows one to analyse the charring rate of pine wood depending on the intensity of heat flux and to draw up the temperature field.

The paper represents the experimental study of combustion over the surface of a vertically-mounted oriented strand board panel under different environmental conditions. An infrared camera was used to obtain the sequences of thermograms characterizing the heat flow pattern on the surface of the sample during vertical combustion and determine the velocity of the combustion wave under laboratory and field conditions. In addition, the change in the angle of the combustion front was estimated depending on time.

The paper presents the results of a comparative analysis of the spectral characteristics of the Schumann resonances in the Russian Altai and the Tomsk Region for the period from 2015 to 2018.

The paper presents the results of a three-year monitoring study of the magnetic component of the EM background in the Altay in the seasonal-daily observation cycle. Describe variations of resonant frequency and amplitude of the first three modes Schumann resonances.

The effect of superheated water vapor on the flame characteristics was experimentally studied by IR thermography in a wide range of operating parameters using a spray burner and diesel fuel. A FLIR thermal imaging camera (JADE J530SB) was used for measurements. The instantaneous and average temperature fields were obtained and time-averaged temperature profiles were constructed along the symmetry axis of flame. The maximum flame temperature as a function of steam consumption at constant fuel consumption was found: with increasing steam consumption, a decrease in temperature is observed, which can positively affect the concentration of hazardous substances in exhaust gases. It was also found that with an increase in fuel consumption at constant steam consumption, the maximum flame temperature shifts from the base of the flame, and the high-temperature flame zone increases. The obtained data can be used for numerical simulation of combustion.

Vertical refraction affects the results of trigonometric leveling. It is known that in the summer period, in the midday time, height differences measured by the total station are less than the true ones, and the angular errors can reach 20ʹʹ and more. During the experiment, on the basis of a length of 364 m, the geodesic method was used to determine the refraction coefficient in winter conditions, with the height of the sighting beam up to 1,6 m. The average coefficient was k=+ 2.3, i.e. in winter conditions, the measured height differences are greater than the true values, and the angular error was +13,5ʹʹ.

The paper presents the experimental study results on the effect of external pressure fluctuations on the temperature field in a flame during the combustion of certain liquid hydrocarbon fuels. It is determined that the height of the flame is changed with an external effect occurrence in the form of small amplitude pressure pulsations. Identified oscillations correspond to the frequency of external sound exposure in the spectrum of flame temperature change.

This paper represents physical and mathematical modeling of the flame flow generated during the combustion of diesel fuel. The scale of vortex structures and the change in the Reynolds number in flame were estimated using the methods of IR thermography. The main thermodynamic parameters of flame are in good agreement with the scale of turbulent vortices in flame.

The paper presents experimental investigation results of turbulent vortices scales in diffusion flames. Comparison of obtained data on the basis of digital tracer visualization and thermography was carried out. A good correlation is obtained between the sizes of large vortex structures in the velocity field, recorded using the PIV method, and the size of temperature inhomogeneities, recorded by flame thermography.

We demonstrate a synthesis strategy to design a compact long-focus catadioptric objective with a field compensator. The compensator is used to increase the field of view (FoV) by correcting tangential coma and astigmatism. The feature of the optical scheme is that the primary and the tertiary mirrors are coincide, i.e. rays are reflected twice from the same mirror. To demonstrate the effectiveness of the synthesis strategy we have designed an F/8 catadioptric objective with 2000 mm focal length and 15 arc minutes FoV.

The distribution of the probability density of fluctuations of the intensity of the scattered radiation of a focused laser beam (0.63 μm) in the near – ground (surface) atmosphere in a haze on a 130 m long path was measured. It is established that the probability density distribution has one maximum. The distribution had the right asymmetry or had a form close to symmetric. The form of distribution does not depend on the wind speed and its perpendicular component to the path at close atmospheric conditions, at close values of the scattering coefficient and the size of the haze particles. Most experimental probability density distributions are approximated by the gamma  distribution.

The results of experimental studies aimed at improving the efficiency of the “telescope-deformable mirror” scheme for the purposes of long-range propagation of intense light channels in the air are presented.

One of the actual problems of the multi-frequency laser remote sensing is the using of the self-action phenomena of pulsed femtosecond laser radiation. When femtosecond laser radiation propagates in the atmosphere, both the transformation of the spectral and spatial characteristics of the radiation dispersion and the pulse duration occurs. The effect of atmospheric air dispersion on the duration of a femtosecond pulse propagating in the atmosphere is discussed via the results of experiments. The fact of compensating of the dispersion spreading of the pulse duration in air by its temporary “compression” under the influence of a change in the phase modulation index in an optically active impurity is not excluded.

A simulation computer model of the optoelectronic path of the active-pulse visualization system is developed, which allows to analyze the influence of the atmospheric channel on the efficiency of the system as a whole. Most attention is paid to the effect of backscattering noise on the output image, as the most significant factor that reduces the contrast between the object and the background. The model provides an estimated-information support of the process of CT scan imaging optical-electronic systems. The basic mathematical relations underlying the model are given.

The results of experimental and theoretical studies of the filamentation of femtosecond laser pulses using a bimorph deformable mirror, which allows controlling the position of the filamentation domain throughout a model path due to phase distortions of different parts of a laser beam, determining localization of filaments and high-intensity channels in the beam cross section.

In the paper, we present an algorithm of the Monte Carlo method for calculating the optical transfer function (OTF) of the ocean-atmosphere system based on a combination of the methods of “correlated sampling” and “conjugate trajectories”. Some numerical estimates of the effect of a number of factors on the OTF system are presented.

A stochastic non-Gaussian model of the random field of the attenuation coefficient in stratus cloudiness is presented, as well as a weighted Monte Carlo algorithm for simulating the optical radiation transfer in a random cloudy medium.

Theoretical and experimental study of nonresonance generation of laser radiation by atoms, molecules and ions of matter - superradiation - is an important area of research in the field of femtosecond optics. Narrowly directed (forward and reverse), with an intensity proportional to the square of the number of inverted atoms, molecules and ions, radiation can be used to probe the atmosphere using femtosecond lidars. This paper presents the results of comparative experimental studies of the appearance of superradiance at transitions of molecular nitrogen ion in the atmosphere and at transitions of atomic strontium ion in a mixture with inert gases (He, Ne) in a heated cuvette. For the first time, superradiance was observed in the transition from the resonant electronic state ²Р_1/2 / to the ground state ²S_1/2 (407.8 nm), when Sr pairs were pumped by radiation at a wavelength of 268.1 nm.

The wind speed in the airport runway was measured using a passive optical method based on a correlation analysis of turbulent distortions of images of distant observation objects. The optical path was organized in the area of the ground section of the glide path near the start of the runway. Against the background of a moderate crosswind, after the aircraft passed above the line of sight, the significant velocity changes, caused by the wake, were stably recorded using the passive optical meter. The results illustrate the practical possibility of using this method for instrumental indication of the presence or absence of wake vortex tracks over the airport. This information can be useful in assessing the safe intervals in the process of organizing departures and landings of aircrafts.

The software has been developed for thematic processing of data of Russian satellite systems. It is based on the algorithm of atmospheric correction developed by IAO SB RAS. The software allows retrieval of the reflection coefficients of the Earth’s surface with the RTM atmospheric correction algorithm in the visible and near-IR range on the assumption of a uniform surface. The software includes converters for reading and unpacking input formats of satellite data and related metadata, an atmospheric correction module, and an auxiliary module for formation of the atmospheric model. The atmospheric correction includes procedures for statistical simulation of the Earth’s surface illumination and for calculation of the spherical albedo of the atmosphere, intensity of radiation noninteracting with the surface, and intensity of radiation reflected by the surface.

The paper presents the results of the development of environmental graphene antennas on paper substrates for operation in 1.8 and 2.6 GHz cellular operators (GSM-1800 and LTE-2600), which can be used for multi-channel systems for the transmission of atmospheric data and ocean information. The design of these antennas, the voltage standing wave ratio, the radiation pattern and the comparison of the experimental characteristics with those calculated are presented. Some features of the manufacturing technology of these antennas are analyzed.

The influence of the receiving aperture size and photo detector array resolution on the accuracy of crosswind speed estimation from the correlation analysis of turbulent distortions in optical images is studied in numerical simulation. Receiving optical system (video camera) parameters optimal for the technique for passive estimation of crosswind speed are determined.

The effectiveness of reconstruction of images formed by single- and multi-aperture systems and disturbed by atmospheric turbulence is analyzed. Based on the numerical simulation, we show that the use of multi-aperture observation systems for the computer correction of atmospheric disturbances under anisoplanatism allows a significant reduction of the exposure time. Main distortions are well corrected in this case during imaging for the short exposure time, which corresponds to the “frozen” turbulence of the medium. The time required for the correction of residual small-scale disturbances is an-order-of-magnitude shorter than in the case where long-exposure images are synthesized with traditional single-aperture observation systems.

The dynamics of spectral components arising in the time interval up to 15 ns after the main femtosecond pulse is investigated for filamentation of tightly focused laser radiation. The femtosecond pulse duration was 65 fs, the main pulse energy increased from 0.5 to 1.7 mJ. Several spectral components of laser emission in the wavelength range of 720–780 nm are registered. With increase of main pulse energy, the shape of the spectrum of the supercontinuum changes, the intensity of the post-pulse and the amplified spontaneous emission increases, and a shift of the component to the blue region is observed. It is assumed that the component whose central wavelength shifts to the blue region with is associated with Rabi splitting of the oxygen atom levels.

The criteria for the transition of laser beams to the regime of the strong optical turbulence based on the variance of intensity fluctuations and the shape of the profile of the average beam intensity in the atmosphere are discussed. Estimates of the path length are made for fixed values of the structural characteristics of fluctuations of the refractive index of the medium, during which the transition to the regime of strong intensity fluctuations a loss of dependence of intensity distribution of laser beam on its initial intensity distribution at the source plane occurs. It is shown that an increase in topological charge leads to an increase in the critical path length, at which the transition of the vortex beam to the regime of strong optical turbulence occurs.

The behavior of the average Umov-Poynting vector of vortex laser beams propagating in the atmosphere under conditions of strong optical turbulence has been studied. An asymptotic expression is obtained for the radial and azimuthal components of the average flux vector of energy density. The criterion of the transition of the vortex beam into the regime of strong optical turbulence, which is constructed on the basis of the obtained streamline equation, is discussed.

This paper studies effects of random anisotropic ionospheric irregularities on the residual error of dual-frequency GNSS measurements. For this purpose, in the phase path equation we take into account second- and third-order corrections associated with geomagnetic effects and ray path bending in the presence of random irregularities respectively. We also examine the influence of the orientation of ionospheric irregularities along geomagnetic field lines (the so-called anisotropy of irregularities) on the third-order residual error of dual-frequency measurements. We simulate the residual error to investigate the conditions under which this effect becomes most significant.

The results of experimental studies of fluctuations of the parameters of a laser beam propagating through a supersonic submerged jet (SJ) at selected distances from the nozzle are presented. The measurements were performed at different distances perpendicular to the beam axis. The results of the analysis of the intensity fluctuations and the directions of the phase front (performed using a coordinate-sensitive photodetector) are considered. The results of studies of the propagation of a laser beam over a wing model, which is installed in a closed wind tunnel T-313, are analyzed.

The present report is devoted to the overview of topography mapping of convex aspheric surface using the created interferometer for large convex optical aspheric surfaces. The testing method is also presented. It is based on an orthogonal ray scheme, where the convex testing surface is illuminated by a collimated beam, that is perpendicular to the optical axis of the surface. The interference pattern is formed on a screen by the interaction of the reference beam passing over the test surface and the object beam reflected from the test surface. The interference pattern is a system of quasi-straight fringes, containing information about the shape of the tested surface as the distance between those fringes. The experimental data obtained on the interferometer and presented.

About development of laser induced breakdown spectrometer for analysis of thin film or layer of particles with size less than 100 nm, deposited on the surface of a transparent substrate.

The angular distribution of the scattered radiation brightness for different observation conditions was obtained in the systems of vision through the atmosphere. Calculations was carried out by Monte Carlo method. The results of numerical experiments are processed on the basis of wavelet analysis

This article is devoted to studying of statistical characteristics of intensity fluctuations of the fundamental BesselGaussian optical beams propagating in turbulent atmosphere. Research of intensity fluctuations is developed by a method of the statistical moments, particularly, the behavior of the fourth-order coherence function of the optical radiation field is analyzed. The asymptotic solution for area of weak fluctuations of intensity is derived, using it calculations of a variance and spatial correlation function of intensity fluctuations of a fundamental Bessel-Gaussian optical beam in turbulent atmosphere are realized. The effect of relative easing of intensity fluctuations of a fundamental BesselGaussian optical beam in comparison with the similar characteristic of a Gaussian optical beam is discovered. It is shown that intensity fluctuations of a fundamental Bessel-Gaussian optical beam are essentially non-uniform in cross-section of an optical beam. Spatial correlation function of intensity fluctuations of a fundamental Bessel-Gaussian optical beam within its first maximum is weakly sensitive to change of parameter of a Bessel optical beam.

The spatial analysis of the wavefront distortions registered by the Shack-Hartmann sensor of the adaptive optics (AO) system of Large solar vacuum telescope have been performed. In the paper the results of analysis of spatial structure of the wavefront within the field of view ~35 arcsec are discussed. It is shown that the wavefront distortions formed within the field of view ~35 arcsec are not random. There are the repetitive hills of spatial crosscorrelation functions in the field of view at the same intervals for different space subapertures. It is shown that spatial crosscorrelation functions do not contain pronounced kernel for finding the exact position of the atmospheric layer contributing to significant distortions in the wavefront incident on the telescope aperture.

Calculations are presented for the atmospheric attenuation of HF/DF laser radiation propagating from a height of 0 and 10 km at angles of 0 and 35 degrees relative to the zenith. The results of numerical simulation of the influence of the turbulent atmosphere using the phase screen method and the position of the radiation detector at altitudes of 200 and 600 km are also presented.

The paper presents the results of an experiment on the formation of vortex optical fields propagating in a convective turbulent medium. The formation of vortex optical fields is carried out with the help of a micromirror modulator.

The distribution of mean intensity of a laser beam backscattered from a remote aerosol layer in the radiation plane is calculated as a function of the intensity of turbulent fluctuations of the refractive index of air at the propagation path. The mean intensity of backscattered radiation is shown to increase in the backward direction in comparison with the case of scattering in a homogeneous medium due to the effect of backscattering amplification in random media. As the intensity of optical turbulence increases, the amplification factor first grows, achieves the maximum level, and then decreases. The zone of manifestation of the backscattering amplification effect in the receiving plane increases in size with intensification of optical turbulence. It is found that the amplification factor depends on the inner scale of turbulence and the regime of diffraction of optical radiation at the transmitting aperture. It is maximal for the regime of spherical wave and grows with an increase of the inner scale. The calculated data on the amplification effect of mean power of the lidar echo signal as a function of optical turbulence intensity, regime of diffraction at the transmitting aperture, inner scale of turbulence, and size of the receiving aperture are reported for the first time.

In 2016 the authors performed space experiments to obtain the tropospheric NO2 field with the horizontal spatial resolution for the first time at the world level reaching 2.4 km. The NO2 fields were restored based on spectral measurements of GSA instrument installed on board the Russian satellites of the Resurs-P series. For the first time, the high spatial resolution of the new method makes it possible to identify local sources of NO2 pollution and their plumes. Good agreement with OMI NO2 observations with resolution 13 km x 24 km confirmed the reliability of the obtained Resurs-P NO2 fields in general. For the validation of high-detailed structures detected in the NO2 fields of GSA/Resurs-P, we are developing methods based on comparisons with chemical transport models. The comparison is performed for Hebei province, the North China Plain, which is the most NO2 polluted area in the world, using Resurs-P data obtained on September 29, 2016. The paper presents preliminary comparison of the Resurs-P tropospheric NO2 field with simulation based on HYSPLIT transport model. For the solution of the problem a high-detailed chemical transport model based on a solution of the nonlinear heat and mass transfer equation is under development. A theoretical background of the methods of asymptotic analysis of multidimensional singularly perturbed problems for the nonlinear heat and mass transfer equation is proposed.

Differential optical absorption spectroscopy (DOAS) gas-analyzer was successfully tested. Ultraviolet light emitting diodes and high pressure Xe arc lamp were employed as a light sources. Recent developments in fibre-coupling telescope technology and the availability of UV LEDs allowed us to construct a portable instrument. The DOAS system consisted of a coaxial telescope, a spectrometer, and retroreflector. Gas analyzer spectral data bank includes more than 40 molecules absorbed in UV spectral region. Minimally detected concentration is the unit of ppb on paths up to 500 m. The results of the field test measurements of pollutants in Tomsk are presented

The possibilities of retrieving the mean relative concentration of methane using pseudo-inverse matrices, fully connected and convolutional neural networks based on signals from the Earth received by a 450 km orbit space-based lidar are considered. It is shown that the random error of methane concentration retrieving for lidar with laser pulse energy of 9 mJ and repetition rate 20 Hz, receiving system size of 68 cm, resolution of 50-60 km is not higher than 30 ppb.

The work reports the results of the measurements of particulate matter (PM), organic (OC) and elemental (EC) carbon mass concentrations, and carbon isotope composition (δ¹³С) in atmospheric aerosol sampled along the route of the research vessel “Academician Mstislav Keldysh” (71 voyage). The measurements were carried out over the Baltic Sea – the North Sea – the North Atlantic – the Norwegian Sea – the Barents Sea from June to August 2018. The increased OC, EC concentrations and the high δ¹³С value in the samples collected off the coast of Greenland are shown to be not due to marine origin, but due to the transfer of atmospheric aerosol formed in Canada during biomass burning (forest fires).

We present the results of the content of 18 PAHs in the atmosphere over Lake Baikal obtained in the course of the shipboard expedition during wildfires in the Krasnoyarsk Territory and Yakutia in July 2018. We have obtained the data on the spatial distribution of the PAHs content and the mass concentration of aerosol particles in the near-water air layer throughout the entire lake area. We have also calculated PAH inflows to the water surface of the lake. Using backward trajectory modelling and satellite photographs, we have traced the movements of plumes from the seats of wildfires towards Lake Baikal.

In this report we present an analysis of lidar measurements of aerosol optical characteristics in the stratosphere over Tomsk, based on which we determined the periods of increased aerosol content after anomalous aerosol layers of nonvolcanic origin from severe forest fires in Canada were recorded in summer-fall period of 2017. Owing to the pyroconvection, the fire products were lifted to the stratosphere and spread over the entire Northern Hemisphere. The thickness of the recorded aerosol layers of non-volcanic origin was comparable to that produced by one of volcanoes in Pacific Ring of Fire in 2006-2012. A background state of aerosol loading has been established in the stratosphere over Tomsk since November 2017. Time series of long-term measurements of integrated aerosol backscattering coefficient В^a_π for the background stratospheric state from 2012 to July 2017 was used to construct a linear regression of the form В^a_π=2.2213•10⁻⁴−1.7936•10^-7•t.
Our regional empirical model of background stratospheric aerosol for 2000-2016 was corrected to include the measurements from 2016 to 2019.

In this paper, we calculated the air quality index (AQI) for 2018 based on data from automated observation posts located in the city of Krasnoyarsk. The influence of individual components (pollutants) on the index value is analyzed.

In this research, we analyzed the long-term variability and seasonal dynamics of NH₄⁺, Ca²+, NO₃^-, SO₄^2- ions prevailed in surface aerosol layer at the monitoring sites in the Baikal Region. During the warm period the chemical composition of the aerosol forms mainly due to the soil-erosion source; during the cold period power plants emissions are the most significant source. Quantitative estimates of the ion content in the aerosol at the monitoring sites, which indicate spatial heterogeneity of its chemical composition in the atmosphere of the Baikal Region, are given.

An analysis of measurement data of surface ozone and nitrogen oxides concentrations near the coastal zone of Lake Baikal is carried out. Features of vertical distribution of surface ozone and its diurnal variations are revealed. The air flow changing play an important role in the diurnal variations of ozone and other small gas impurities under the conditions of breeze circulations. The air flow changing substantially affect to the transport and dispersion of atmospheric impurities in the region. Features of structure and dynamic of meteorological processes in an atmosphere of coastal zone of Lake Baikal are noted.

Here, we present the results of a mobile campaign undertaken in late October to early November of 2018 to survey heterogeneity of the spatial distribution of CO₂ and CH₄ concentrations across West Siberia using the Picarro G4301 mobile gas concentration analyzer. The measurements were carried out along the following routes Tomsk–Karasevoe– Tomsk and Tomsk–Omsk–Tobolsk–Noyabrsk–Tobolsk–Chelyabinsk–Omsk–Tomsk. The highest baseline level of carbon dioxide mixing ratio of 431.0±2.2 ppm was observed at the western route segments between Chelyabinsk and Kurgan, and the lowest ones at segments Tomsk – Karasevoye, Demyanskoe – Noyabrsk, and Tobolsk – Yalutorovsk, where average concentrations of CO₂ were 410.1±1.1 ppm, 410.7±1.6 ppm, and 411.5±1.5 ppm, respectively. Enhanced methane background (> 2000 ppb) was recorded in the oil and gas production areas, as well as in the vicinity of such large industrial centers as Kurgan and Chelyabinsk.

A lidar system was designed on the basis of parametric light generation with nonlinear KTA and KTP crystals, which allow turning laser radiation in the near and mid infrared spectral regions. Lidar echoes were experimentally detected in the 1.8–2.5 and 3–4 μm wavelengths ranges.

The problem of evaporation in diffusion mode is solved by using linear operators approach for two identical interacting large atmospheric aerosol drops heated by internal heat sources in the case when heating of drops occurs due to absorption of monochromatic radiation falling on them. The formula for the correction factor to the formula for the complete evaporation time of a single aerosol drop is given. The dependence of the correction factor on the radiation intensity and the center distance of the drops is analyzed.

Results of measurements of optical and microphysical characteristics of atmospheric aerosol at the Mys Baranova ice base in 2018 are analyzed. Peculiarities of monthly average variability of aerosol characteristics are considered. The data are compared with the analogous (in particular, many-year) data obtained at the Barentsburg polar station and the midlatitudinal Fonovaya Observatory. The impact of transported smokes on the measured parameters is demonstrated.

A series of laboratory experiments was carried out to measure the absorption of the IR OPO laser radiation by methane within a calibrated CH₄:N₂ molecular mixture in a gas cell. The results of measurements of the laser radiation absorption at sounding wavelengths selected are presented and compared with the calculation results. Backscattered signals in the 3.30–3.43 μm spectral range are detected and processed with the use of the IR OPO lidar system designed along a horizontal sounding path in the atmosphere. Based on the experimental results, the absorption coefficients are estimated and the CH4 concentrations along a 800 m surface path are retrieved in the spectral range under study with a spatial resolution of 100 m.

Carbonaceous aerosol originating from forest fires and other types of open biomass burning (BB) is known to have a strong impact on the radiative balance of the atmosphere but available model estimates of the corresponding climate effects are characterized by large uncertainties due to insufficient knowledge of its sources and atmospheric transformations (aging). Here we study the atmospheric aging of BB aerosol by analyzing data of satellite measurements of the absorption and extinction aerosol optical depths (AAOD and AOD) in BB plumes from wildfires in Siberia. Along with the aerosol measurements, our analysis involves satellite data for CO column amounts as well as the simulations of the BB aerosol photochemical age using a chemistry transport model. The analysis includes the two main stages. First, we study the BB aerosol evolution as a function of its photochemical age by using the observations over Siberia in the period from May to September of 2012. Second, we examine changes in the BB aerosol optical characteristics in the smoke plumes that had been transported from Siberia into the European part of Russia in July of 2016. The results indicate that photochemical aging strongly affects the behavior of both AAOD and AOD. The results also show that aged BB aerosol becomes less absorptive at the near UV wavelength range, indicating a depletion of brown carbon in particles. The BB aerosol aging effects detected at the both stages of the analysis are found to be consistent.

We presented the time series (1994-2017) of the total ozone (TO) content over Tomsk, obtained using M-124 ozonometer. These data were used to compose the average annual behavior. After the TO time series was processed to remove the annual oscillations, its variations were examined for a normality of the distribution. Annual and semiannual TO variations have been manifested in the Fourier spectrum. Application of simpler methods of statistical analysis allowed us to identify the quasibiennial oscillations.

The analyzer RGA/m is presented for measurements of mercury vapor concentrations in ambient air. It is based on a method of the atomic absorption spectroscopy. The emission source used in the analyzer is a low-pressure capillary lamp filled with mercury of natural isotope mixture. The transverse Zeeman Effect is used to split emission line into fine components. The several features of this analyzer are demonstrated.

We discuss the specific features of the spatial distribution of aerosol and black carbon concentrations in the near-ground atmospheric layer, as well as of aerosol optical depth (AOD) over the North Atlantic and Arctic Ocean according to measurements in two marine expeditions in 2018. On the average, the spatial distribution shows aerosol characteristics, decreasing with the growing latitude (from the Baltic to Barents Sea), and comparably low characteristics over Arctic seas, from the Barents to Eastern Siberian Sea. The average aerosol characteristics over the Arctic Ocean were: 4.8 cm^-3 for number concentrations of particles (with diameters of 0.4 – 10 μm), 40 ng/m³ for black carbon mass concentration, and 0.048 for AOD (0.5 μm). The largest characteristics were obtained in the south of the Barents Sea (near Scandinavia), with values 11 cm^-3 for particle concentration, 310 ng/m³ for black carbon concentration, and 0.164 for AOD (0.5 μm).

A method for calculating the motion characteristics of fractal-like aggregates based on the use of gas-kinetic results for homogeneous spherical particles is presented. The essence of the technique consists in replacing the real fractal aggregate by equivalent sphere with the mobility radius and in approximation of density and thermal conductivity of particles by their effective values. This method confirmed its efficiency in comparison with known experimental data.

Results of multiyear expedition studies are used to create the updatable Database of atmospheric aerosol characteristics in different regions of the World Ocean. The database summarizes the measurements onboard research vessels (47 expeditions over 30 years) of aerosol optical depth in the wavelength range of 0.34-2.14 μm, particle number concentration (0.4-10 μm), mass concentration of absorbing substance (black carbon), as well as the content of watersoluble ions and elements in aerosol.

Based on multiyear (2004-2018) studies of atmospheric aerosol on the route of the Russian Antarctic expeditions (from English Channel to Antarctica), we analyze the specific features of interannual variations in aerosol optical depth of the atmosphere and aerosol and black carbon concentrations in four latitude zones of the Eastern Atlantic (25°N – 60°N, 20°N – 0°, 5°S – 33°S, and 40°S – 63°S). Data on interannual variability ranges of aerosol characteristics in different zones and trend estimates are presented.

The effect of meteorological parameters on the spectral aerosol extinction coefficients ε(λ) in the near-surface layer of the marine and coastal atmosphere is studied. The results obtained are of interest both in the calculations of radiative characteristics of the atmosphere, and in the calculations of energy properties of the optical signals in optical-electronic devices of different purposes in the wavelength range ▵λ = (0.2 – 16) μm.
The MaexPro model is shown to calculate adequately ε(λ) and concentration of sea salt aerosol (SSA) particles for different wind regimes, fetches, and humidity. The calculated ε(λ) profiles well agree with experimental data and with calculations using ANAM code. The results thus obtained give a new explanation for the effect of decreasing transparency, manifested in coastal zone, and make it possible to account for indirectly the type (marine or coastal) of air mass.

Results from preparatory stage of studying the seasonal and interannual variations in atmospheric aerosol optical depth (AOD) at two Arctic stations on the Spitsbergen Archipelago (Ny-Ålesund and Barentsburg) are presented. The first task in the preparatory stage was to identify and sort out suspect measurements of spectral AOD in multiyear time series of observations at the Ny-Ålesund station. The second task was to select an optimal method of estimating two AOD components, caused by attenuation of radiation by fine- and coarse-mode aerosol. Comparative analysis of application of four types of methods showed comparable results: average error of estimating two AOD components is less than 0.01.

Multiyear (1995-2018) time series of photometer observations of characteristics of aerosol optical depth (AOD) and columnar water vapor of the atmosphere are used to analyze the specific features of their seasonal and interannual variations, taking into consideration the results, obtained in the last four years. It is noted that the annual AOD behavior persistently exhibits two maxima (in spring and summer periods), mainly attributed to the increased content of fine-mode smoke aerosol. The interannual variations in AOD and in concentration of coarse-mode particles show a statistically significant trend, with the decreases being, on the average, respectively about 0.013 and 0.006 μm³/μm² per decade.