Home – Home – Jornals – Atmospheric and Oceanic Optics 2020 number 9

Absorption in the 1-0 CO band wing broadened by He at different temperatures is regarded within the asymptotic line wing theory. It presents absorption as a sum of the absorption coefficients of individual line with a special shape at far distances from the line center. The line shape parameters pertaining to quantum and classical interaction potentials are found as a result of fitting to the experimental absorption data in the 1-0 CO band wing and the temperature dependence of the second virial coefficient.

The ¹³CH₄ absorption spectra in the range between 7400 and 7600 cm^-1 have been recorded at for temperatures from 296 to 200 K by the Fourier spectrometer IFS-125M at a spectral resolution of 0.03 cm^-1. A 220 cm cell was used, which provided a threshold sensitivity to absorption on the order of 10^-6 cm^-1. Line assignment of the n₂ + 2n₃ band of the ¹³CH₄ molecule was performed. Rotational constants of the (0120) state and the integral intensity of the n₂ + 2n₃¹³CH₄ band were determined for the first time.

To compensate for aberration of laser radiation passed through a turbulent atmosphere, a wavefront corrector was designed in the form of a cooled stacked-actuator deformable mirror. In this work, theoretical estimations which allow one to determine main characteristics of this mirror are represented. The method suggested for cooling the reflecting surface of the wavefront corrector developed through piezoactuators body is experimentally studied. The results of measurements of main characteristics of the deformable mirror are shown, including the initial mirror surface shape, response functions of actuators, stroke of the mirror, and first resonance response of the mirror surface.

The conditions for the occurrence of two pump beams propagating at an angle to each other, in which highly directed white SC beams are formed, are investigated and analyzed. The beams are formed due to aberration focusing of a femtosecond radiation pulse with a wavelength of 940 nm. It is shown that the mechanism of their formation is related to the diffraction of the pump beam on the filament plasma in the meridional focus region and Kerr self-focusing of radiation. The dynamics of development of these beams is demonstrated.

Urban emissions of black carbon (BC) were studied, since BC is the most significant component of the polluted atmosphere of the Arctic region. Three-months continuous measurements of BC mass concentrations were carried out in April-August 2019 at the aerosol station near the Salekhard city with an AE33 seven-wavelength aethalometer. Using a concentration probability function for BC concentrations measured under different wind speed and direction, potential sources of emissions have been identified. In the north-west direction from the station, the sector of urban emissions was detected, where the range of BC concentrations was from 73 to 135 ng/m³. According to official data, transport and thermal power plants, which use diesel fuel, gasoline, and natural gas, are the major Salekhard urban emission sources. In April-May and June 2019, the average BC concentrations in urban emissions were 133 ± 80 and 105 ± 80 ng/m³. In July, during a period of intense forest fires on the Polar Circle, they attained 350 ± 120 ng/m³ and identified the contribution of smoke plumes to the aerosol loading and deterioration of the urban air.

Results of the complex experimental study of the spectral and temporal characteristics of the emission glow of control samples of several substances in the solid state (imitation of topographic targets in the atmosphere) and in the form of solid aerosols (imitation of air pollutants) under the action of femtosecond pulses of a Ti:Sa laser (at a carrier wavelength of 800 nm) and nonlinear optical effects are presented.

The aim of this work is to summarize the results of the study of the development of a high-depth thunderstorm over water area of the Gulf of Finland. A waterspout was observed under the base of the cloud. Remote sensing methods were used in the study. The general conditions of atmospheric instability, microphysical and electrical characteristics of the cloud are considered. Cloud microphysics and its relation with lightning frequency are discussed. High correlation was discovered between the frequency of lightning discharges and supercooled volume of the cloud, as well as precipitation flux.

The review provides information on the ozone concentration in the surface air and troposphere in the first half of 2020. The data were acquired at 13 stations in different Russian regions; vertical distributions were obtained with the use of the aircraft laboratory. The excess over the Russian Federation hygienic standards was assessed; the daily average maximum permissible ozone concentration is found to be regularly higher at most stations. At some stations, there are features which differ the seasonal variations in the ozone concentration in the period under study from previous years.

The process of the formation of a plume of NO₂ emitted into the atmosphere by a point source is considered with the use of a new method for reconstructing NO₂ distribution fields in the troposphere from GSA Resource-P satellite data and mathematical simulation. The functional form of the model is ascertained, which agrees in complexity with the amount of available experimental information. The values of the model parameters are found. The emission power is calculated. The reliability of the simulation results is estimated from the comparison of the calculations with the experimental data on the distribution of the altitude-integral amount of NO₂ in air depending on the horizontal coordinates.

The results of a comprehensive experiment carried out to derive the vertical distribution of methane in the troposphere over Western Siberia from solar spectra recorded with a IFS-125M Fourier transform spectrometer, in situ aircraft measurements, and satellite observations are describean, analyzed, and compared.

Methods and results of numerical forecast of ice phenomena over the territory of the central Russia for winters 2003-2018 are presented. The forecast success is compared using the analysis of precipitation types and the heat balance model, where the predictions of the WRF-ARW model are used as input. Some advantages of forecasts using a heat-balanced model are shown. It is suggested to develop an integral method in the future.

The dynamics of forest loss from fires in the Verkhneketsky district of the Tomsk region is considered. The volumes of pollutant emissions resulting from fires are calculated. It was established that in the Verkhneketsky region smoke aerosols from the fires of 2012 and 2016 in terms of mass significantly exceed technogenic emissions from stationary sources. It is shown that smoke from fires spreads over a distance of more than 30 km. According to CALIOP lidar data, smoke elevations were estimated to be from 1.3 to 4.3 km, which does not contradict the calculations based on model formulas.