Home – Home – Jornals – Atmospheric and Oceanic Optics 2024 number 5

An expert assessment of the accuracy codes for the intensities of rovibrational transitions of water vapor in the spectral range 2500-6500 cm^-1 of the HITRAN2020 database has been carried out. From comparison with experimental data, the normalization coefficients of the variational calculation by Conway E.K., Gordon I.E., Kyuberis A.A., Polyansky O.L., Tennyson J., Zobov N.F. // J. Quant. Spectrosc. Radiat. Transfer. 2020. V. 241. P. 106711 were determined; for the absorption bands (001)-(000), (020)-(000), (011)-(000), and (110)-(000), they were 1.010, 1.007, 1.013, and 1.030, respectively. Using variational calculations and modeling based on the effective Hamiltonian approach, the analysis of experimental data from the HITRAN2020 database has been conducted, revealing less accurate values. Based on these results, an adjusted list of H₂¹⁶O absorption lines in the range 2500-6500 cm^-1 has been constructed, which can be useful for natural experiments.

The influence of two factors on the contour of an absorption line of water vapor molecule in a mixture with helium, argon, krypton, and xenon is studied: the dependence of the broadening coefficients γ and shifting coefficient δ on the velocity ν_a of the absorbing H₂O molecule (wind effect) and the change in the velocity of H₂O upon collision with these atoms. Three absorption lines of H₂O molecule from n₁ + n₂ + n₃ band with different rotational quantum numbers of the initial quantum state were chosen for the study.

The results of long-term measurements of the atmospheric turbulence characteristics in the Sayan Solar Observatory (SSO) in summer 2023 are presented. It is confirmed that the cause of the prevailing direction of local winds appearing in SSO is temperature mountain-valley gradient between the Sayan Mountains north of the SSO observatory and the valley to the south. A smaller level of the mean intensity of atmospheric turbulence in SSO compared to the turbulence over flat terrain in middle latitudes is confirmed. The presence of coherent turbulence in the SSO area is shown, at which the quality of images obtained by optical instruments is improved. New data are obtained for the turbulent scales of temperature and wind speed depending on the atmospheric stratification.

The impact of PM_2.5 in urban air on the frequency of hospitalizations for respiratory diseases is studied based on data on the atmospheric PM_2.5 concentration from the TOR station (Tomsk) and on the number of hospitalizations of Tomsk residents for respiratory diseases and coronavirus infection (ICD-10 codes J00-J99, U07.1, and U07.2) from the register of emergency calls over a twelve-year period (2010-2022). It is shown that the level of air pollution with PM_2.5 and the duration of pollution episodes almost do not affect the number of hospitalizations for respiratory diseases in the absence of infectious agents, which increase the number of such hospitalizations. However, in the cases where infectious agents, including SARS-CoV-2, are present in urban air, which promotes an increase in the number of hospitalizations for respiratory diseases, fine aerosols as carriers of the infectious agents contribute to their faster transfer and infection of more city residents compared to the cases of clean air. During such episodes, relatively low PM_2.5 concentrations (30-50 μg/m³) can several times increase the number of hospitalizations for respiratory diseases, including coronavirus infection, even in such a fairly clean city as Tomsk, ignoring the rise of the number of hospitalizations due to seasonal morbidity or epidemic.

In this article, we have calculated light backscattering by large irregularly shaped particles with random orientations. We have utilized the physical optics approximation to analyze this phenomenon. Our findings demonstrate that there is a distinct polarization surge in the degree of linear polarization, which arises from coherent backscattering. The sign of the polarization surge for pairs of conjugate beams can vary, being either negative or positive, depending on the light beam trajectorie which significantly contribute to the backscattering process. By summing up these surges, we have concluded that the well-known phenomenon of negative polarization not necessarily occur when a single particle scatters light in the vicinity of the backscattering direction.

A flight experiment was carried out in which turbulence was sounded with the UV lidar BSE-5 from the Tu-134 Optik laboratory aircraft. The experiment was conducted in September 2022 as part of the Arctic exploration program. During the flights, lidar recorded zones of moderate turbulence in the lower troposphere, where the probability of turbulence is maximal, and isolated cases of clear air turbulence (CAT) at an altitude of 9 km. The intensity of the aircraft shaking was monitored using a 3-coordinate accelerometer. It was found that the turbulent lidar can be used in practice for remote detection of turbulent zones at altitudes where most commercial flights are carried out. The prospect of ground-based application of turbulent lidar for solving aviation safety problems during flights in the lower troposphere is shown. The results of the BSE-5 lidar sounding in winter, when an increase in the intensity of turbulence in the 0.4-1.6 km layer was recorded during the passage of a cold front, are presented.

The article discusses some characteristics of the propagation of atmospheric waves based on photographic observations of noctilucent clouds in the city of Yakutsk. For the first time, a case of observation of the so-called mesospheric boron in noctilucent clouds over Eastern Siberia, recorded synchronously with two cameras of the same type, has been described. The height of the wave front determined by the triangulation method was 79 km. The case of video recording of the propagation of several waves of different lengths with intersecting directions in noctilucent clouds on July 25, 2018 is analyzed. Analysis of the parameters of two waves propagating towards each other showed that the first has average wavelength of 53.5 ± 6.2 km, average phase velocity of 98.4 ± 12 m/s, and northeast direction. The second wave of the scallop type propagated to the southwest with an average phase velocity of 61.5 ± 6 m/s, its average wavelength was 14.8 ± 1.8 km. The speed of westerly wind drift of all clouds was 67 ± 5 m/s.

The influence of aerosol particles on the parameters of the global atmospheric electrical circuit is among important issues of the theory of atmospheric electricity. This paper presents a theoretical model of the effect of aerosol particles on the global atmospheric electrical circuit (GEC) under the fair weather. Surface aerosol is considered as a summand in the total atmospheric columnar resistance. Electric field generators which support the GEC are taken into account through the boundary condition as specified ionospheric potential. In addition to the theoretical model, experimental observations of electrical characteristics of the atmosphere and of the aerosol concentration are presented. The theoretical and experimental studies make it possible to estimate the concentration of submicron aerosol particles.

The processes of planetary wave breaking (Rossby Wave Breaking - RWB) significantly contribute to variability in stratospheric circulation. Employing a previously developed method for identifying RWB, adapted for stratospheric circulation, this study analyzes the climatology and long-term variability of RWB processes in the middle stratosphere. The method is based on the analysis of potential vorticity (PV) contour geometry at the 850-K level using ERA5 data within the PV range 0-400 PVU (Potential Vorticity Units) determined based on PV field climatology. It was demonstrated that RWB processes exhibit intraseasonal peculiarities. Most frequently, waves break in the northern regions of East Asia and the Pacific Ocean from October to December and in April to March. In January and February, no areas with prevailing RWB processes were identified. We obtained statistically significant increase in the number of RWB for the first half of winter (October-December) and for the end of the winter period (March and April). For mid-winter (January and February), insignificant negative trends were obtained.

The influence of early sudden stratospheric warming (SSW) on the stratospheric polar vortex is presented. The definition of SSW and their classifications have been formulated for a long time, but detailed information is not available about the early (in November - the first half of December) SSW. The determination of early SSW was carried out in two ways using the zonal averaged values of temperature and zonal wind component with and without the climatic component. The polar vortex's response to warming is represented by the geopotential height field. The study was conducted using JRA-55 and Merra2 reanalysis data. Also, the variation of surface temperature and surface pressure during the displacement and splitting of the stratospheric polar vortex during the early SSW is presented based on sounding data at stations of the polar region of different continents. It is known that the VSP has a significant impact on the weather in the troposphere, including the dynamics of the upper atmosphere.

The paper considers the possibilities of taking into account data from lightning networks in the procedure for lightning data assimilation in numerical models of atmospheric dynamics. A universal procedure is proposed and the code is implemented within the framework of the WRF-ARW model. According to the data from lightning detection networks, the cells of the computational grid are determined, in which lightning was recorded. Then moisture is iteratively added in these cells until the occurrence of thermodynamic instability and, hence, convection. The effect of using this scheme on the forecast of precipitation, temperature, and humidity is studied, and a comparison is made with other lightning assimilation methods. The use of data from lightning detectors makes it possible to locally improve the forecast of heavy precipitation and temperature in areas where thunderstorms were observed. The Piercy-Obukhov coefficient for forecasting intense precipitation using the proposed procedure increases from 0.26 to 0.40.

Temperature data at weather stations in the Northern Hemisphere and astronomical insolation data are ordered by increasing latitude and analyzed together for different samples between 1897 and 2010. By step-by-step regression of the latitudinal variation in the long-term average temperature to a polynomial of astronomical insolation, a latitudinal temperature trend determined by the Sun and fluctuating regression residuals, in which individual features of data appear, are identified. The absence of interaction of these components is numerically achieved for any samples. It has been established that in the Northern Hemisphere for the available samples, the latitudinal trend in the long-term average temperature completely determines the warming and contributes about 82% to the total temperature dispersion. The boundaries of areas where temperatures are above and below the latitudinal trend in the long-term average temperatures reveal known geographic structures, thereby verifying the trend.