Institute Of Atmospheric Optics Research Articles

Atmospheric Research for Adaptive Optics

Adaptive optics (AO) systems are an essential part of large astronomical telescopes and laser complexes operating through the atmosphere. Each AO system is individually designed; the requirements for the components and the performance of an AO system are determined by the intensity and distribution of turbulent fluctuations of the air refractive index over the radiation propagation path. In this work, we review the techniques and instruments for measuring and forecasting atmospheric conditions for AO, including devices and techniques developed at the Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences. The basic principles of atmospheric AO and the related atmospheric parameters are briefly described. Particular attention is paid to the parameter used for the estimation of capabilities of AO systems, i.e., the wind speed at a level of 200 hPa. The comparison with the data from foreign astronomical observatories is carried out. The necessity for atmospheric research for large Russian astronomical observatories is discussed.

Temporal variability of submicron and coarse aerosol concentrations in the surface air layer at the Aerosol Station of Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, Tomsk (2000-2020)

Temporal variability of submicron and coarse aerosol concentrations in the surface air layer at the Aerosol Station of Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, Tomsk (2000-2020)

Мониторинг изменчивости стратосферного слоя аэрозоля над Томском в 2016—2018 гг. по данным лидарного зондирования

The results of observations of the features of intraannual variability for the vertical structure of background aerosol in the stratosphere over Western Siberia in 2016–2018 are presented and analyzed. Experimental data were obtained at the lidar complex of Zuev Institute of Atmospheric Optics (Siberian Branch, Russian Academy of Sciences) with a receiving mirror diameter of 1 m. The objective of the study is to investigate the dynamics of background stratospheric aerosol, since during this period there were no volcanic eruptions leading to the transport of eruptive aerosol into the stratosphere. The results of the study confirm a stable intraannual cycle of maximum aerosol filling of the stratosphere in winter, a decrease in spring to the minimum, practical absence in summer, and an increase in autumn. At the same time, the variability of stratification and aerosol filling is observed for different years. It was found that aerosol is concentrated in the layer up to 30 km all year round, except for the winter period. It is shown that the vertical aerosol stratification is largely determined by the thermal regime of the tropo- sphere–stratosphere boundary layer. The absence of a pronounced temperature inversion at the tropopause contributes to an increase in the stratosphere–troposphere exchange and, as a result, to the aerosol transport to the stratosphere. This situation is typical of the cold season. For the first time, data on the quantitative content of stratospheric aerosol (its mass concentration) were obtained from single- frequency lidar data.

Numerical Simulation of Meteorological Conditions and Air Quality above Tomsk, West Siberia

This paper presents the simulation results of meteorological and air quality parameters for the Siberian city of Tomsk predicted by mesoscale meteorological and chemical transport models. Changes in the numerically predicted wind velocity fields, temperature, and concentration of major air pollutants were modelled in detail for the selected dates, when anticyclonic weather with cloud free and calm wind conditions was observed in Tomsk. The simulation results have shown that stable or neutral atmospheric stratification with light wind and low ambient air temperature (−30, −20 °C) are the most unfavorable meteorological conditions leading to the near surface pollutants accumulation. The numerical calculation results were compared with observation data from the Joint Use Center (JUC) “Atmosphere” of V.E. Zuev Institute of Atmospheric Optics (IAO) and showed good agreement.

Bank of Spectral Line Parameters of the H2S Molecule

A bank of spectral line parameters of the principal isotopologue of the hydrogen sulfide molecule (H232S) is presented. The databank is based on the global simulation of line positions and intensities of this molecule within the method of effective operators. Parameters of the global effective Hamiltonian and effective dipole moment operator were derived from their fitting to the line positions and intensities observed, respectively, which were taken from the literature. The databank covers the 552.76–8424.32 cm−1 spectral range and includes the calculated values of the following spectral line parameters: line position and intensity, energies of lower and upper states, Einstein coefficient for the spontaneous emission, and the statistical weights of the lower and upper states. The intensity cutoff was chosen equal to 10−28 cm/molecule at T = 296 K. In total, the databank contains about 88 thousand lines. This databank is deployed on the website of V.E. Zuev Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences ( ftp://ftp.iao.ru/pub/H2S/ ).

Lidar Methods and Tools for Studying the Atmospheric Turbulence at the Institute of Atmospheric Optics

Main results of works carried out during last five years at the Institute of Atmospheric Optics on the creation of lidar methods and tools for studying atmospheric turbulence are surveyed.

Studying the Variations in Aerosol Loading and Thermal Regime of the Stratosphere Over Tomsk on the Basis of Lidar Monitoring

One of the important applications of lidar techniques is the study of aerosol content and thermal regime of the stratosphere. Such investigations in monitoring mode were initiated at the Institute of Atmospheric Optics since 1986 (for aerosol) and 1994 (for temperature), and are continued to the present. The main attention is paid to studying the annual variations in aerosol content in the stratosphere and sudden disturbances caused by winter stratospheric warming. In this paper we present the results of studying the aerosol content and its vertical stratification and vertical distribution of temperature in the stratosphere over Tomsk for the last three years.

Synergy of Ground-Based and Satellite Optical Remote Measurements for Studying Atmospheric Aerosols

The methodology for integrated ground-based and satellite monitoring of atmospheric aerosols is discussed. An algorithm for processing data from coordinated lidar and radiometric sensing (LRS) is described. The algorithm was tested by studying aerosol parameter altitude profiles in the vicinity of AERONET stations using data from ground-based solar radiometers and CALIOP satellite lidar. Coordinated measurements with AERONET network radiometers and ground-based multiwavelength lidars at remote sensing stations of the Institute of Physics, NASB (Minsk, Belarus), Institute of Atmospheric Optics, SB, RAS (Tomsk, Russia), and KRSU (Teploklyuchenka, Kyrgyzstan) were used to verify the satellite sensing results.

Atmospheric Correction of Satellite Images of the Earth’s Surface in the Optical Wavelength Range. Optical Communication Based on Scattered Radiation

The results obtained at the Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, from 2010 to 2019 regarding problems on atmospheric correction of satellite images of the Earth’s surface and of optical communication based on the scattered laser radiation in the optical wavelength range in the atmosphere and under water are briefly reviewed.

Singular Atmospheric Optics: From Wavefront Dislocations to Synthesis of Vortex Laser Beams

Studies on the singular optics of scalar wave fields carried out in the world and at V.E. Zuev Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences (IAO SB RAS) are reviewed. The study results of the processes of origination and annihilation of phase singularities are generalized. The methods for singular phase reconstruction and their applicability to the problems of adaptive focusing of radiation in randomly inhomogeneous media are examined. The energy, statistical, and topological properties of vortex optical beams propagating through a turbulent atmosphere are analyzed. The results of the synthesis of vortex beams with quickly controllable orbital angular momentum by the matrix approach developed at IAO SB RAS are described.

Optoelectronic UV Communication on Scattered Laser Radiation

Previous and new results on the problems of optical communication in scattered laser radiation in the UV wavelength range, obtained at the Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, are discussed. Field experiments on optoelectronic communication in night- and daytime conditions in 2017 and 2018 are presented.

Modified Beam-Splitting 1 (MBS-1) Algorithm for Solving the Problem of Light Scattering by Nonconvex Atmospheric Ice Particles

A new algorithm for solving the problem of light scattering by nonconvex crystals typical for cirrus clouds is presented. It is based on the beam tracing algorithm for convex particles (Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences). The new algorithm is applied for solving the problem of light scattering by hollow-column particles and aggregates of hexagonal ice columns. It is an opensource freely available algorithm.

Estimation of the Effect of Meteorological and Orographic Conditions on Aerosol Contamination of the Snow Cover in the South of Tomsk Region

We analyze the dynamics of layer-by-layer variations in aerosol contamination of snow cover under the circulation conditions during winter at the site of the Fonovaya Observatory (Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences) in the Tom-Ob interfluve. The chemical composition of the snow cover at the observation point is characterized. It is found that in the elemental composition of the aerosol substance accumulated in the snow cover, a typomorphic association of indicator elements associated with coal mining is consistently manifested. The conclusion is geochemically substantiated that enterprises of the coal-mining industry, located southward of the region under study, have a seasonal effect on the aerosol field of the Fonovaya Observatory. It is shown that the remote sources of aerosol contamination of the snow cover should be identified through the morphometric analysis of the terrain and a retrospective estimation of temporal variability of the indices, reflecting the effect of meteorological factors (ratios of dispersion fractions of near-surface aerosol, wind regime, snowfall intensity), and in the context of specific features of the layer-by-layer distribution of indicator groups of typomorphic elements in the snow layer that characterize the specific types of industrial plants.

Lidar Complex for Measurement of Vertical Ozone Distribution in the Upper Troposphere–Stratosphere

A lidar complex designed at V.E. Zuev Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences (Tomsk) and used at the Siberian Lidar Station (56.5° N, 85.0° W) for the study of ozone dynamics near tropopause and for tracking global ozonosphere changes is presented. It allows measurements of ozone vertical distribution in the upper troposphere–stratosphere when sounding using the differential absorption technique at the wavelength pairs 299/341 and 308/353 nm. The lidar complex covers altitudes from ∼5 to ∼45 km.

Variations in Condensation Properties of Mixed Smoke from Biomass Burning at Different Smoke Evolution Stages

The variations in the optical-microphysical properties of the mixed wood smoke are studied in the Large Aerosol Chamber, Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences (volume of 1800 m3) during long-term (6-day) smoke aging under the conditions of periodic impacts of relative air humidity varying in the range 45–95%. Spectral nephelometric measurements of angular scattering and solution of the inverse problem were used to analyze the dynamics of the size distributions and complex refractive indices for ultrafine, medium-sized, and coarse fractions of particles, as well as effective particle radius, lidar scattering parameter, and single scattering albedo in the visible spectral range. It is found that both quantitative and qualitative features of the variations in the aerosol optical-microphysical parameters substantially change at different smoke aging stages as functions of air humidity. It is shown that, during aging of the mixed smoke, the key factors of the variations in smoke properties are the physical-chemical heterogeneity of three fractions of smoke particles, as well as the physical processes of coagulation migration of ultrafine black carbon particles (<100 nm in size) across the size spectrum and the condensational wetting of smoke particles. The interrelated effect (“interference”) of these processes on the particle structure determines the main features of the dynamics of the disperse composition and absorption properties of smoke particles.

Lidar investigations of thermal regime and aerosol stratification of the stratosphere over tomsk

One of the important applications of lidar techniques is the study of thermal regime and aerosol content of the stratosphere. Such investigations in monitoring mode were started at the Institute of atmospheric optics since 1994 and are continued to date. The main attention is paid for the study of the unexpected disturbances caused by winter stratospheric warming. In this paper we present the results of the study of the vertical distribution of temperature and aerosol over Tomsk of last years.

Siberian lidar station: instruments and results

The Siberian Lidar Station created at V.E. Zuev Institute of Atmospheric Optics and operating in Tomsk (56.5° N, 85.0° E) is a unique atmospheric observatory. It combines up-to-date instruments for remote laser and passive sounding for the study of aerosol and cloud fields, air temperature and humidity, and ozone and gaseous components of the ozone cycles. In addition to controlling a wide range of atmospheric parameters, the observatory allows simultaneous monitoring of the atmosphere throughout the valuable altitude range 0–75 km. In this paper, the instruments and results received at the Station are described.

Interannual variations in aerosol microstructure parameters according to data of sun photometer measurements in Tomsk

Results of studying the time variations in aerosol microstructure parameters retrieved by inverting the spectral measurements of the aerosol optical depth are presented. The input data were obtained at the Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences using SP-type sun photometers during periods of observations in 2003–2006 and 2011–2014. During the first period, aerosol optical depth was measured at 13 wavelengths in the range 0.37–4 μm. In the second period, the upper boundary of the wavelength range of measurements was 2.14 μm. The total amount of data processed had been more than 7000 hourly average spectra. The aerosol microstructure parameters, such as the geometric cross section, volume concentration, and average particle radius, were analyzed.

Verification of a passive correlation optical crosswind velocity meter in experiments with a Doppler wind lidar

The results of comparative experiments on measurements of the crosswind velocity by the passive correlation optical method and with a coherent Doppler wind lidar are analyzed. The passive correlation optical measurements were carried out with a crosswind velocity meter developed at the Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences (IAO SB RAS).

Influence of 3D cloud effects on spatial-angular characteristics of the reflected solar radiation field

Spatial-angular characteristics of reflected solar radiation in broken clouds are simulated in the spherical model of the atmosphere using statistical algorithms developed in the Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences. The patterns of formation of radiance fields of scattered radiation, caused by the finite cloud extents, mutual cloud shading, and radiation re-reflection by neighboring cloud elements are considered by the example of individual cloud realizations. It is shown that, for small and moderate cloud fractions, the specific features of the radiance field of reflected solar radiation are mainly determined by cloud localization relative to the viewing direction and direction “toward the Sun”.