Atmospheric and Oceanic Optics最新文献

The form of the vibrational-rotational operator of kinetic energy for linear symmetric molecules of the A₂B₂ type in polyspherical nonorthogonal internal coordinates (bond lengths and angles between bonds) is obtained. Nonorthogonal coordinates have advantages in calculating the wave functions of heavy linear molecules, for example, C₂F₂ and C₂Cl₂; they also simplify the calculation of the intensity of vibrational-rotational spectral lines of molecules belonging to this type. This work is a continuation of work [1], in which the form of the kinetic energy operator in orthogonal coordinates was obtained. To verify the expressions derived, the lower vibrational-rotational energy levels of the acetylene molecule are calculated.

The paper presents the results of studies of the content of particulate matter PM₁–PM₁₀ in the atmosphere of the western coast of Southern Baikal with high temporal resolution. It has been established that PM are emitted into the atmosphere of Southern Baikal from both anthropogenic and natural sources. In winter, the influence of thermal power facilities increases, as evidenced by synchronous increases in the concentrations of submicron aerosol PM₁ and sulfur dioxide. In summer, remote forest fires make a significant contribution to atmospheric pollution with particulate matter. The relationship between the increase in the concentration of PM₁ in the atmosphere in the region under study and mesometeorological features (temperature inversions and mesoscale transfer of plumes from large thermal power plants) has been revealed. Increases in PM₁ concentrations in most cases occur during the night and morning hours, which is associated with a decrease in the thickness of the atmospheric boundary layer.

Results of experimental studies of aerosol in the surface air layer in the southeastern part of the Crimean Peninsula at the background environmental monitoring Vyazemsky Karadag Scientific Station from March 21 to June 17, 2020, are presented. The daily average mass concentration of aerosol ranged from 3 to 35 μg/m³ over the measurement period, with an average value of 13 μg/m³. The exception are high concentrations during the episode of March 25–27, 2020 (48, 195, and 49 μg/m³, respectively), when an extreme eastward transfer from sources in Kazakhstan (a dust storm in the region of the Aral Sea) through Kalmykia to the Crimea took place. Accounting this episode, the daily average mass concentration of aerosol was 16 μg/m³. Days with different directions of airmass arrival and days with the highest daily average mass concentrations of aerosol are distinguished out of 89 observation days. For this set (31 samples), the concentrations of 64 chemical elements in the samples are determined. Accumulation of chemical elements in soil and in aerosol particles is estimated; the clarkes of concentrations of chemical elements in soil, aerosol concentration coefficients, and enrichment factors of chemical elements in aerosols are calculated. The dependences of the mass concentration, size distribution, and elemental composition of the surface aerosol on long-range aerosol transport are considered.

The paper considers changes in the state of the environment in Krasnoyarsk and its environs during the existence of the smoke of large-scale Yakut fires in August 2021. The appearance of smoke aerosols in the atmosphere weakens the solar radiation flux reaching the Earth’s surface and, accordingly, decreases the temperature of the active soil layer and the surface air layer. Advection of cooled air with high relative humidity over the surface of the Yenisei River in the lower downstream of the Krasnoyarsk HPP formed cooling fogs.

The results of experimental determination of near-surface aerosol density for particles of different composition and size have been published over many years. Based on the generalization of these data, as well as the results of our own field observations of microphysical characteristics and composition of Moscow aerosol, an algorithm and parameters for numerical estimation of mass concentration of submicron and micron urban aerosol are suggested. Using this algorithm, on the basis of experimental data on the size distribution function of aerosol particles in the diameter range 0.3–10 μm obtained during regular observations at IAP RAS in Moscow in 2020–2022, the mass concentration of near-surface aerosol of various fractions was calculated. A comparative analysis of the results of such an assessment and the data of synchronous measurements of mass concentration of aerosol particles using a portable aerosol spectrometer GRIMM 1.108 over the past two years has shown a good correspondence between the calculated and measured values. Density values for four ranges of aerosol particle sizes are selected for more correct numerical estimation of the mass concentration of urban aerosol of fractions PM_2.5 and PM₁₀.

Gases desorbed by the vacuum method from the tree rings of discs of deciduous trees are measured. The content of residual gases vacuum-desorbed from tree rings is analyzed with an optoacoustic gas analyzer with a tunable CO₂ laser. The chronologies of residual CO₂ and (CO₂ + H₂O) of some deciduous trees growing near the city of Tomsk (Western Siberia) have been derived. All the chronologies are cyclic with pronounced 2–4-year cycles. A correlation was found between the content of gases and summer temperatures and precipitation. We believe that the annual distribution of residual gases in the discs reflects the pattern of annual release of the gases from the stems of the deciduous trees into the atmosphere.

The ecological state of the Arctic hydrocarbon field territories over the period 2013–2022 is estimated. Vegetation cover is considered an indicator of the ecological state of the territories under study. Based on the Terra/MODIS satellite data, the state of the vegetation cover of hydrocarbon fields in the Purovsky District of the Yamal-Nenets Autonomous Okrug is studied: Urengoyskoye, Vostochno-Tarkosalinskoye, Gubkinskoye, Vyngayakhinskoye, Komsomolskoye, and Tarasovskoye. Using the ArcGis geographic information system, the average values of EVI (Enhanced Vegetation Index) of the field vegetation cover for the full growing season from May 25 to September 20, 2013–2022, are calculated. The EVI minima and maxima for the territories are determined. Tendencies towards an increase in EVI in the final period of the growing season over the 10-year period under study are found.

We simulate and examine the absorption dynamics of the near-infrared optical radiation in a spherical microcapsule surrounded by solid nanoparticles of different optical properties (metal, biocompatible dielectric) with the use of numerical finite-difference time-domain (FDTD) calculations. A model microcapsule resembles a microcontainer used in modern bio- and medical technologies for targeted delivery of therapeutic nanodoses of drugs to the desired region of biological tissues. We show that the optical field superlocalization in the “hot regions” on the microcapsule surface takes place due to light scattering on nanoparticles. The three-fold light absorption enhancement can be achieved due to the addition of buffer nanoparticles.

The Fried’s length r₀, the outer scale L₀, the isoplanatism θ₀, the coherence time τ₀, and the profile of the optical turbulence energy (C_{n}^{2}(h)) are parameters of the wavefront spatiotemporal coherence. Numerous optical methods are used to determine the images quality through the estimation of the parameters r₀, L₀, θ₀, and τ₀, where numerical simulations of the transversal and longitudinal covariance (as a function of the angle-of-arrival (AA)) play a significant role. In this work, we, first, perform the statistical analysis of the fluctuations of angle-of-arrival using theoretical models of the atmospheric turbulence, and second, the statistical analysis of the AA fluctuations in solar limb images. This analysis plays a significant role in the optimization of techniques, such as adaptive optics (OA) and in interferometry, in astronomical observations with high angular resolution.

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 exciting laser radiation are derived. It is ascertained that the dependence of the PO fluorescence signal on the energy density of the exciting radiation is 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 exciting radiation energy density.