Atmospheric and Oceanic Optics最新文献

Desertified areas are the main source of dust aerosol. The emission and transport of dust aerosol in the near-surface layer of the atmosphere are markedly affected by electrification of the wind-sand flux. Electrical processes in a wind-sand flux have been studied experimentally. Based on data of synchronous measurements of the density of saltation electric currents and currents caused by transport of charged dust aerosol particles at heights of 4 and 12 cm in a desertified area in Astrakhan oblast, statistical characteristics of variations in the density and density moduli of these currents are calculated. It is shown that in a wind-sand flux in the height range from 4 to 12 cm, the density modules of saltation electric currents and currents caused by transport of dust aerosol decrease with height much more slowly (the logarithmic gradients are −0.025 and −0.07 cm⁻¹) than the concentration of saltating particles (the logarithmic gradient is −0.32 cm⁻¹). It is confirmed that the moduli of saltation electric current density correlate with each other and with the wind speed in the surface air layer more closely than the current densities themselves. The results obtained are of interest in developing models of dust aerosol emission in desertified areas.

Accurate measurements of the concentration of nitrous oxide, a potent greenhouse gas, in the Earth’s atmosphere are important for modeling the radiation balance of our planet. The work presents the measured broadening and shift coefficients of N₂O lines by air pressure at room temperature for 82 rovibrational transitions in the (00⁰2) ← (00⁰0) band; the rotational quantum number m varies from 3 to 54. The measurements were carried out with a Bruker IFS-125M Fourier transform spectrometer with a spectral resolution of 0.0056 cm⁻¹. The calculated line-broadening and shift coefficients were obtained using a semiclassical method modified by introducing a correction factor in the calculation scheme. Our parameters are compared with those presented in the literature and in modern spectroscopic databases. A vibrational dependence of the line halfwidths is revealed for the ν₃ stretching vibration.

The purpose of the study is to describe the seasonal variability of optically active components in the Sea of Azov based on data from the combined MODIS-Aqua/Terra satellite observation product and a three-dimensional hydrodynamic model. The paper discusses the results of testing a method for retrieving missing data in remote sensing images from the results of three-dimensional hydrodynamic simulation. The method has been tested for four main biooptical parameters: the concentration of chlorophyll-a and pheopigments (TChl), coefficients of light absorption by phytoplankton pigments (a_ph(678)) and non-living organic matter (a_CDM(438)), and light backscattering coefficient (b_bp(438)). The results derived from the combined product were compared with in situ observations carried out in April–May 2019 at the scientific research vessel Professor Vodyanitsky. The deviations of the average TChl values according to MODIS and simulation data from in situ observations was 1.8 and 2.2 mg m⁻³, respectively. The analysis of the calculated series of main biooptical parameters derived through regular assimilation of MODIS data into a hydrodynamic model made it possible to ascertain their seasonal variability in the central part of the Azov Sea in 2019. Among the biooptical parameters under study, the pronounced seasonal variability of TChl stands out with, an average annual of 2.98 ± 1.22 mg m⁻³. Changes in a_CDM(438) and b_bp(438) are characterized by two periods of maximal values: spring (March–May) and autumn (August–October), with corresponding annual averages of 0.42 ± 0.15 and 0.10 ± 0.03 m⁻¹. Maximal changes in a_ph(678) are observed from July to October with an annual average of 0.04 ± 0.03 m⁻¹. The suggested approach uses advantage of remote sensing data, which expand the capabilities of operational oceanological monitoring, and simulation data, which enable filling gaps in these data. The results provide complete continuous data sets on the distribution of main biooptical indicators, which are crucial in predicting the ecological state of sea basins.

For five isotopologues of the SO₂ molecule: ³²S¹⁶O₂, ³⁴S¹⁶O₂, ³³S¹⁶O₂, ³²S¹⁸O₂, and ³²S¹⁶O¹⁸O, parameters of the effective vibrational Hamiltonian are derived from fitting to the available experimental data, as well as using the basic relations of the isotope substitution theory. Vibrational constants obtained from the fit reproduce the experimental vibrational energy levels within 0.025 cm^–1 for symmetric isotopologues. The obtained vibrational energy levels are compared with the variational calculation, and the quantum numbers for 93 vibrational states are corrected.

Contribution of carbonyl compounds into the generation of atmospheric organic aerosol in the presence of typical urban air pollutants is investigated. Aldehydes and ketones entering the atmosphere from natural and anthropogenic sources are identified by means of high-performance liquid chromatography. Field measurements were carried out on the territory of Novosibirsk scientific center and in adjacent forest areas. It is shown that the transport of typical gaseous urban air pollutants (nitrogen oxides and ozone) into the air of forest areas and the transport of biogenic compounds (alkenes and aldehydes) to the urban territory cause sharp changes of the kinetics and mechanism of organic aerosol generation in comparison with the processes taking place in typical urban atmosphere. Thus, in the presence of ozone, the yield of aerosol products from formaldehyde, acetaldehyde, and propanal photonucleation increases by a factor of 4–8, while for benzaldehyde and acrolein it exhibits 5- and 30-fold decrease, respectively. For aromatic substituted aldehydes and furfural, aerosol yield slightly increases (only up to 30%). The results make it possible to carry out quantitative evaluation of the capacity of natural and anthropogenic sources of organic aerosol in the forest-steppe zone of Western Siberia and predict the biological effect of aerosol generated in the presence of various pollutants.

Comparison of satellite measurements with independent measurements is an essential and necessary component of validation of satellite data. In this work, we compare the spectrometric measurements of the NO₂ content in the atmosphere by the Ozone Monitoring Instrument (OMI) in 2004–2020 with the ground-based twilight zenith measurements at 14 stations of the Network for the Detection of Atmospheric Composition Change (NDACC). We obtained the latitudinal distributions of NO₂ content and of the comparison characteristics: differences in the contents and the correlation and linear regression coefficients between the satellite and ground-based data. Criteria are proposed for testing the interannual and long-term changes in NO₂ content derived from the OMI data based on the ground-based measurements. The latitudinal—hemispheric and regional—features of the correspondence between the satellite and ground-based data have been revealed. Significantly new results have been obtained on the dependence of the comparison characteristics on the level of pollution of the lower troposphere with nitrogen oxides and on the timescale of NO₂ variations: day-to-day, seasonal, and interannual. The results will be useful in the analysis of NO₂ variability based on OMI data.

Abstract—Infectious diseases affecting the respiratory system are currently a serious medical problem. One of the ways of increasing the effectiveness of therapy for such diseases is targeted delivery of drugs. This approach requires the development of new methods for generating aerosols of drugs with particle sizes which enable penetrating into specified areas of the respiratory system. In this work, a technique for generating dry aerosol particles based on ultrasonic spraying of a drug solution is suggested and implemented. Using the example of a solution of the medicinal antifungal substance fluconazole, we show that this technique enables generating aerosol particles with stable concentration and average size for more than 2 hours. The resulting aerosol has optimal inhalation parameters: size from 1 to 1.9 microns and concentration of 70 000 ± 6500 cm⁻³. The suggested technique makes it possible to further study the biological effect of aerosols of drugs.

The absorption spectrum of the ¹⁴N¹⁷O molecule was recorded in the 5200–5550 cm⁻¹ range for the first time using a Bruker IFS-125M Fourier spectrometer with a spectral resolution of 0.0056 cm⁻¹. The analysis of the spectrum made it possible to detect 83 vibrational-rotational lines of the 3–0 band of the fundamental transitions in the X ²Π electronic state of the ¹⁴N¹⁷O molecule. For 29 resolved doublets, the positions and relative intensities of each component of a doublet are determined; the spectroscopic Λ-parameters are found. For the remaining 25 unresolved doublets, the positions and relative intensities of the doublet center are determined. The maximal rotational quantum number J was 24.5. The experimental line positions in the 3–0 band confirmed the calculated data given in the ExoMol database. The frequencies of recorded transitions weighted in accordance with experimental uncertainties have been processed, and the spectroscopic constants for the vibrational state ({v}) = 3 have been determined. With the found spectroscopic constants, the rotational energy up to J = 30.5 in the vibrational state ({v}) = 3 and the transition frequencies in 3–0 vibrational band for ²Π_1/2 and ²Π_3/2 electronic states were predictive calculated. The calculations showed agreement with the data given in the ExoMol database within a specified error.

The Erebus volcano is the southernmost active volcano on Earth, whose volcanogenic emissions include components which play a significant role in catalytic cycles of stratospheric ozone depletion. High cyclones contribute to the rise of gas emissions from the Erebus volcano (including HCl and SO₂) from the troposphere to the altitudes of ozone hole formation, from 14 to 22 km in the stratosphere. The paper considers the integral content of HCl and ClONO₂ for the period 1992–2023 and analyzes the variability of the frequency of high cyclone occurrence for the period 1980–2022 based on the ERA5 reanalysis data. It is revealed that the maximal frequency of occurrence of high cyclones over the Erebus volcano is usually observed in July. The integral HCl content over Antarctic stations is much higher than over Arctic ones and approximately twice as high as over midlatitude stations. The effect of HCl accumulation in the stratosphere is shown: the coefficient of correlation between 5-year average frequencies of occurrence of high cyclones and 5-year average areas of the ozone hole with a 4-year shift ahead of the series of ozone hole areas relative to the series of high cyclone frequencies, calculated for the period from 1980 to 2022, amounts 0.78.