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The spectrum of the ¹⁵N¹⁶O molecule in the region 5200-5500 сm^-1 is recorded and analyzed. As a result of the analysis, 150 Λ-doublets of vibration-rotational lines are found in the 3-0 band of the main transitions between the ²Π_1/2 and ²Π_3/2 electronic states. For 108 of them, when the splitting value was greater than 4.5 × 10^-13 сm^-1, it was possible to obtain the positions and relative intensities of each component of the doublet, while the self-expansion parameter was fixed to the value from HITRAN2020, and the intensities of the components e and f were considered equal. The maximum of the rotational quantum number J was 30.5. The frequencies of the transitions recorded, weighted in accordance with the experimental uncertainties, were processed by the program code using the non-linear least squares method. As a result of processing, the spectroscopic constants for the v = 3 vibrational state of the ¹⁵N¹⁶O isotopologue are found. The Λ-doubling constants for this state are determined for the first time. The results are compared with the well-known database of spectroscopic information HITRAN2020.

Today, the gas-adsorption porosimetry technique is standard for determining the pore sizes of nanoporous materials. However, it requires liquid nitrogen, and measurements take a long time. We have suggested a spectroscopic technique for determining the pore diameters of nanoporous silicon materials from the absorption spectra of water adsorbed in a material (Atmos. Ocean. Opt. 2021. V. 34, N 6. P. 542-546). In this work, this technique is used to measure the pore size of zeolites. The pore sizes of five samples are estimated with the use of the regression analysis. The values obtained by the spectroscopic technique are in a good agreement with measurements by the standard one: the error of the spectroscopic technique is less than 10%. In terms of speed, the spectroscopic technique exceeds the standard one by dozens of times. The spectroscopic technique can also be applied to determining the static water capacity of materials.

The results obtained at Institute of Atmospheric Optics SB RAS and abroad in studying the broadening and shifts of H₂O absorption lines by monatomic gases He, Ar, Kr, and Xe are reviewed. The experimental studies at IAO SB RAS were carried out in the spectral range 3200-11200 cm^-1 using a Bruker IFS 125 Fourier spectrometer. The broadening and shift coefficients were measured for the lines of 24 vibrational bands with maxim of vibrational quantum numbers v₁ = 3, v₂ = 6, and v₃ = 3 and of rotational quantum numbers J = 14 and K_a = 8. The calculations were carried out by the semiclassical method using effective vibrationally dependent potentials. The experimental and calculated values of the broadening and shift coefficients are compared. Using the analytical model γ(sur), available experimental data on the broadening coefficients are analyzed, and their incompatibility is revealed in some cases. The model parameters γ(sur) are determined which allow generating the coefficients of broadening of H₂O absorption lines by He, Ar, Kr, and Xe atoms in the range 350-14000 cm^-1.

The work analyzes the spatial distribution of carbon dioxide over the seas of the Russian sector of the Arctic based on the results of the comprehensive experiment conducted in September 2020. It turned out that during the experiment, the concentration of CO₂ increased from west to east. The minimum 396 ppm was over the Barents Sea, and the maximum, over the Chukchi Sea - 4106 ppm. The difference in concentrations between a level of 200 m and the free troposphere reached -156 ppm over the Barents Sea and decreased to -56 ppm over the Laptev Sea. Over the eastern seas, the difference generally became positive, which was associated with the air transfer from Alaska. Above the waters of most seas, horizontal heterogeneity in the distribution of carbon dioxide was observed, reflecting the regional features of its assimilation by the ocean and transfer from the continent.

Carbon monoxide (CO) total column (TC) measurements of the TROPOMI high-resolution orbital spectrometer have been validated by ground-based spectroscopic measurements at sites of the A.M. Obukhov Institute of Atmoshperic Physics, Russian Academy of Sciences, in Moscow and Zvenigorod for the period from June 28, 2018, to December 31, 2021. Correlation coefficients ( R ) between TROPOMI orbital data and ground-based stationary data are determined and analyzed. The high values of the correlation coefficient are obtained ( R ~ 0.81-0.97) depending on the observation point, spatial averaging, and filtration applied. For different averaging of satellite data, the dependences of correlation parameters on the orbital angles, underlying surface albedo, and the height of atmospheric boundary layer are investigated. No influence of albedo on the correlation parameters of orbital and ground-based measurements is found for both observation sites. No significant dependence of correlation parameters on the viewing zenith angle is detected either. However, the correlation coefficients depend on the viewing azimuthal angles and the height of the atmospheric boundary layer. An increase in the correlation is obtained during observations at viewing azimuthal angles of less than 40° (up to R ~ 0.97), as well as under an increase in the height of the atmospheric boundary layer (up to R ~ 0.90).

An impact of uncertainties of the atmospheric gases absorption line parameters in the modern spectroscopic databases on the longwave fluxes simulation in the atmosphere is estimated. The mass calculations of downward and upward IR fluxes are carried out for meteorological conditions observed in summer months in the Lower Volga Region and winter months in Novosibirsk and for average zonal meteorological models. The radiative fluxes and cooling rates at different levels of the atmosphere calculated with use of new versions of HITRAN and GEISA spectroscopic databases and its previous versions are compared. It is shown that the difference in absorption line parameters in the spectroscopic databases leads to an error less than 0.7 W/m² (0.3%) in the simulated integral fluxes in the 0-3000 cm^-1 region, at that the relative differences in the spectral fluxes calculated with moderate spectral resolution (20 cm^-1) are up to 10%. The atmospheric gases and spectral intervals contributing more to the errors in the IR fluxes simulations due to uncertainties of initial spectroscopic information are revealed.

The seasonal and daily variations in the radiation extinction coefficient due to midges (RECM) in Western Siberia are calculated for June, July, August, and September 2018. The average RECM values in the visible and infrared spectral regions were ~ 0.06 km^-1 in June, ~ 0.05 km^-1 in July, ~ 0.04 km^-1 in August, and ~ 0.02 km^-1 in September. There are two maxima in the daily variations in June, July, August, and September. The first maximum falls at 9 a.m. The second maximum is more pronounced and is observed at 17 p.m. The RECM is minimal in nighttime and at noon. In addition, a different daily behavior is characteristic for certain days of September, with a maximum in daytime and a minimum in nighttime.

We present a mathematical model of the process of laser-induced fluorescence of phosphorus oxide (PO) molecules. Based on the model, the dependences of the fluorescence intensity of PO molecules on the energy and time parameters of the exciting laser radiation are derived. It has been established that the dependence of the PO fluorescence signal on the energy density of the exciting radiation has the form of a saturation curve, and the dependence on the pulse duration under real atmospheric conditions has a local maximum. It is shown that the optimal pulse duration decreases with the energy density of the exciting radiation.

A mobile ozone lidar for sounding at wavelengths of 299 and 341 nm was designed and put into operation. The lidar is capable of covering the altitude range from 0.1 to 12 km with a spatial resolution of lidar signals from 1.5 to 150 m. The specification of the mobile lidar is given; the results of a field experiment on laser sounding of the atmosphere in Tomsk are presented. Echo signals received and the ozone profiles retrieved confirm the information content of lidar measurements in the troposphere. The results of lidar and satellite (MetOp) measurements are compared.

We compare the main characteristics of the Arctic polar vortex obtained from the NASA GSFC data (zonal mean wind at 60° N, mean temperature in the region 60-90° N) and by the vortex delineation method using geopotential (mean wind speed along the vortex edge, mean temperature inside the vortex) on the example of three largest Arctic ozone depletion events and on average over 1979-2021. The mean wind speed along the vortex edge according to the delineation method is on average two times higher than the zonal mean wind at 60° N and is 37.3 ± 5.6 and 58.9 ± 13.1 m/s in January at the 50 and 10 hPa levels, respectively. The mean temperature inside the vortex according to the delineation method is on average 5 °C lower than the mean temperature in the region 60-90° N in the lower stratosphere. The quantitative characteristics obtained expand the understanding of the Arctic polar vortex dynamics in the lower stratosphere.