Home – Home – Jornals – Atmospheric and Oceanic Optics 2024 number 12

The SO₂ - CO₂ line profile parameters are important to study the carbon dioxide atmospheres of terrestrial planets (Venus, Mars) and exoplanets. The carbon-dioxide shift coefficients of sulfur dioxide lines in ν₁ + ν₃ band are calculated at room temperature; the rotational quantum numbers J varies from 0 to 100 and K_a varies from 0 to 20. Calculations were made using a semi-empirical method, which includes a correction factor with adjustable parameters depending on the rotational quantum numbers. The calculated shift coefficients are in a good agreement with few published data.

Absorption by carbon monoxide in a mixture with argon is considered on the basis of the asymptotic line wing theory. Line contour parameters, related to the quantum potential of intermolecular interaction describing absorption in the short-wavelength wing of the CO rotational band have been found. This contour is used for describing continuum absorption within the longwave wing of the CO rotational band, leading to agreement with experiment. Thus, the line contour obtained can be applied for estimation of the CO continuum absorption within the CO rotational band.

The parameters of the spectral model of small-scale turbulence are the most important characteristics used to describe the propagation of light and sound in the atmosphere. One of the determining factors affecting the spectral composition of turbulence is the stratification regime. Based on the processing of time series of fluctuations of meteorological parameters recorded by acoustic weather stations, the effect of stratification of the surface air layer on the deviations of the turbulence spectrum from the Kolmogorov-Obukhov model is investigated. When comparing the time dynamics of the stability characteristic (Monin-Obukhov number) and the index of the power model of the spectrum of temperature fluctuations, a significant correlation between them is established. An empirical model of the dependence of the spectrum index on the stability parameter is proposed. The model makes it possible to estimate changes in the parameters of the spectral structure of small-scale turbulence based on estimates of the magnitude and direction of turbulent heat and momentum fluxes. The dependence reflects the features of generation of temperature turbulence with different stratification in the surface layer. Information on turbulent spectral parameters obtained on the basis of estimation of stratification can be further used to solve problems of propagation, of optical and acoustic as well as sounding of the atmosphere.

Atmospheric aerosols have a significant impact on air quality, climate, and human health. The comparison of gaseous impurity and ionic composition monitoring data in the surface atmosphere over Antwerp and Beijing showed that the hygroscopicity level of dense haze particles over Beijing in winter is determined by the depth of heterogeneous reactions of sulfate and nitrate formation. The paper discusses the dynamics and mechanisms of these non-photochemical processes, as well as the features of their coupling in a haze-polluted atmosphere. Their rapid occurrence in particles in combination with the absorption of water vapor from the air causes abnormally high mass concentrations of aerosol and their variability during the haze period over Beijing. The results are necessary for forecasting the occurrence of dense hazes, as well as for constructing models of transfer of gas and aerosol microimpurities in the atmosphere.

The paper investigates the generation of THz radiation in the filamentation process. The possibility of increasing the generation efficiency of terahertz (THz) radiation in a single-color filamentation mode excited in air by laser beams with necklace amplitude profile is considered. A stationary model of THz radiation generation is proposed, which allows us to study the dependence of conversion efficiency on the amplitude profiling of pump beams. It is shown that the partitioning of radiation over subapertures allows controlling the energy of THz radiation. The optimal class of gorget beams is found by the genetic algorithm method. The results of this work are important for the development of technologies for remote generation of THz radiation in gaseous media.

The ongoing global warming leads to the need for continuous monitoring of greenhouse gas concentrations and the magnitude of their fluxes. Gas exchange between terrestrial ecosystems and the atmosphere is mainly measured using eddy covariance, gradient, and chamber methods. This work compares greenhouse gas fluxes measured using the airborne eddy covariance technique and by means of the gas analysis system and meteorological sensors at the ZOTTO observatory. A description of instrument suites of the aircraft laboratory and observatory is presented. The comparison results showed that CO₂ and CH₄ fluxes measured by two different methods at the same altitudes coincide in sign, are close to each other in value for carbon dioxide, and differ by up to 2 times for methane. The results are of interest to specialists who study greenhouse gas fluxes using the eddy covariance method.

The paper presents the results of lidar measurements of the vertical ozone distribution in the lower stratosphere - upper troposphere at the Siberian Lidar Station (SLS) of V.E. Zuev Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, over Tomsk in 2023. The annual variation in the vertical ozone distribution and the increased ozone content in the lower stratosphere - upper troposphere recorded in March 2023 are shown. It is assumed that the event of high ozone content in the lower stratosphere - upper troposphere on March 9 was caused by a rather rare process of stratospheric - tropospheric transfer of an air mass through the tropopause.

The study of internal gravity waves (IGWs) generated in the atmospheric boundary layer (ABL) under stable temperature stratification and the mechanisms of interaction of IGW with wind turbulence are important for understanding the dynamic processes in the atmosphere and improving the algorithms of ABL numerical modeling and weather forecasts. This work is devoted to the study of wave structures and turbulence in stable ABL using the data of our experiments conducted in 2023. In these experiments, two pulsed coherent Doppler lidars (PCDL) horizontally spaced 3250 m apart were simultaneously used. The analysis of the experimental results has shown that from the measurements of two PCDLs it is possible to determine the time shift of the moments of passage of the leading edge of an atmospheric wave through the lidar locations, which is used to determine the propagation velocity of the atmospheric wave. For the first time in our lidar experiments, the case of atmospheric wave propagation in the layer at altitudes from 200 m to 1 km with a maximum amplitude of quasi-harmonic oscillations of the vertical component of the wind speed vector of about 4 m/s (at an altitude of 400 m) was revealed. It is established that due to the transfer of energy from an atmospheric wave to small-scale wind fluctuations, it is possible to increase the turbulent energy dissipation rate by four orders of magnitude in just a few tens of minutes.

A system has been created for numerical prediction of concentrations of pollutants in the atmosphere and their deposition to the ground using the Chimere chemical transport model, which takes into account emissions from stationary, emergency, and mobile sources. The forecast of meteorological fields was carried out using the regional high-resolution non-hydrostatic atmospheric model WRF-ARW. The system is fully automated, which allows it to be used as a tool for quickly obtaining operational information in the work of situation centers and decision-making centers in the cases of industrial, natural, and man-made emergencies. The results of testing the system showed its operability, the possibility of using it in operational and research work, as well as in scenarios of development of emergency situations anywhere in the country and implementation of measures to assess and eliminate the consequences of accidents. The first results of the calculation of atmospheric pollution with the system are presented. They can be considered as test. To obtain statistically reliable results, it is necessary to have longer series of measurements of atmospheric pollution concentrations and of higher resolution.

Cirrus clouds play an important role in formation of the climate of our planet, as far as they influence its radiation balance. Their study requires solving the problem of interpreting atmospheric laser sounding data, which is solved differently for clouds consisting of randomly oriented ice crystals and clouds containing layers of horizontally oriented crystals. In this article, within the framework of the physical optics method, light backscattering properties for horizontally oriented ice particles of cirrus clouds of the “plate”, “column” and “hollow column” type were numerically simulated. Simulations were carried out for particles ranging in size from 10 to 316 µm for wavelengths of 0.532 and 1.064 mm with refractive indexes for ice of 1.3116 + i 1.48 × 10^-9 and 1.3004 + i 1.9 × 10^-6. The solution was obtained for typical lidar tilt angles of 0, 0.3, 3, and 5°. The results are of interest for developing an optical model of cirrus clouds for interpreting atmospheric laser sounding data in case of cirrus clouds containing this types of particles.

The article presents statistics on the distribution of aerosol particles during the summer vegetation and winter dormancy of woody plants at the size Fonovaya observatory of the IAO SB RAS (Tomsk Region) from July 1, 2022, to June 30, 2023. The analysis of the ratios of aerosol fractions revealed a paradoxical situation, where the count concentration of aerosol particles 0.3-2.0 mm diameter turned out to be significantly higher in winter than in summer. A phenomenological model is suggested which describes this effect as a manifestation of the action of radiometric forces.

The main results of investigations of energy and time characteristics of laser pulse transmission in the range from 0.36 to 1.55 mm along horizontal and inclined mountain paths with lengths from 0.05 to 8.5 km at altitudes from 1100 to 2100 m at ILP SB RAS research site “Kaitanak" in the Altai Mountains are presented. The characteristics of optical interference in the UV- A range at different altitudes were measured. Experimental estimates of optical signals reception in the range of 0.36 mm and 0.45 mm by UAVs at a distance of up to 1.5 km from ground-based laser emitters are obtained. The parameters of retroreflectors for laser signals after operation for several years at remote mountain posts are given. The totality of the obtained characteristics opens new possibilities of building laser environmental monitoring systems for remote control of dangerous deformations of mountain slopes and rockfalls, snow accumulation, and occurrence of fires, storms, etc.