Vol 31, No 5 (2018)

The possibility of estimating the optical refractive index in the atmospheric boundary layer from air temperature profiles measured with a MTP-5 meteorological temperature profiler is studied. The refractive index profiles retrieved from MTP-5 data and from aerological measurements are compared. Examples of the refractive index and its derivatives for different seasons are given.

The software was created to automatically retrieve the water vapor continuum absorption from experimental data. The program includes a baseline correction (if required), automatic correction of the experimental spectrum by frequency, automatic “spectroscopic” correction of the pressure measured, subtraction of spectral line local contributions, automatic selection of transparency microwindows most reliable for continuum retrieving, and, smoothing of the values obtained. The software is currently intended to be used for processing Fourier transform spectrometer FTS absorption spectra, but it can be adjusted for other experimental methods.

Models for estimating the average and maximum concentrations of chemically active impurities in cross sections of their plumes from remote stationary sources are proposed. The models were tested with the use of aircraft sounding data on the multicomponent contamination of the winter atmosphere in the Norilsk industrial region. The process of gas–particle active transition observed at a distance of 58–103 km from the emission source is numerically studied. The average and maximum sulfur oxidation rates in the winter polar atmosphere are estimated as 0.027–0.034 and 0.055–0.07 h⁻¹, respectively.

Near-ground propagation of monochromatic acoustic radiation at frequencies of 300, 1000, 2000, and 3150 Hz along atmospheric paths up to 100 m long is investigated experimentally and theoretically depending on altitudes of the acoustic source and receiver. The experiment was carried out at the experimental site of the Institute of Monitoring of Climatic and Ecological Systems (IMCES) using a specially developed setup. The dependence of the recorded sound pressure level on the propagation path length and initial signal power is analyzed. The theoretical analysis is performed by the Monte Carlo method using the local estimation algorithm developed by the authors. The comparison of the experimental and theoretical results shows their satisfactory agreement, which indicates the effectiveness of the proposed algorithm and its applicability to predicting the near-ground sound propagation.

The variability of time series of the integrated water vapor of the atmosphere and the surface partial pressure of water vapor for the territory of Europe over a long period have been studied. The main contribution to the variance of both integrated and surface water vapor is made by seasonal variations of 60–70%; mesoscale processes, 7–17%; and synoptic processes, 17–27%. The linear trend contributes less than 1% to the overall variance of the variability of the atmospheric water vapor in Europe. It has been shown that the interannual variability of the atmospheric water vapor manifests itself both in quasi-periodic variations in the annual average values and in variations in the intensity of synoptic processes. The irregular coherence of variations in the circulation indices and surface partial water vapor pressure in Europe with periods of 2–3, 5–6, 8–11, and 10–13 years has been established.

Based on long-term (2004–2016) expedition studies, statistical generalization and zoning of aerosol physicochemical characteristics in the eastern Atlantic (from the English Channel to Antarctica) are performed. For six latitudinal zones of the Atlantic and Southern Oceans (>45°N; 20°–45°N; 0°–20°N; 0°–20°S; 20°–55°S; >55°S) the average values of the main aerosol characteristics are presented, i.e., atmospheric aerosol optical depth (AOD), fine and coarse AOD components, particle number concentrations, and mass concentrations of aerosol, black carbon, and water-soluble ions (Na⁺, Mg²⁺, Cl⁻, K⁺, Ca²⁺, \(\rm{NH}_4^+, \rm{NO}_3^-, \rm{SO}_4^{2-}\)), as well as of gas admixtures (SO₂, HCl, HNO₃, NH₃). It is shown that the zonal variability range of optical and microphysical aerosol characteristics is about an order of magnitude: the largest (minimal) average values are observed in the tropical zone (over Southern Ocean). The zonal differences (a factor of 1.3 to 4.3) in concentrations of ions and gas admixtures are much smaller and comparable to synoptic-scale variations. The concentrations of “marine” ions are maximal over the Southern Atlantic, and those of “continental” ions in the Northern hemisphere tropical and subtropical zones; the concentrations of all ions are minimal over the Southern Ocean. The specific features of geographic distribution of gas admixtures are noted: the maximal concentrations of HCl and NH₃ are observed over the Southern Atlantic, those of SO₂ and HNO₃ near Europe, and the lowest level is observed in the tropical zone.

Measurement results of a complex of aerosol microphysical, chemical, and optical parameters in two cruises of the Akademik Mstislav Keldysh research vessel in 2016 are analyzed. The work was carried out in the Kara Sea from July 10 till August 20 and in the Barents Sea from August 25 till October 10. The mean values of the following aerosol characteristics are given: AOD of the atmosphere, fine and coarse components of AOD, number concentration of particles in the near-water air layer, mass concentrations of the absorbing matter (soot), water-soluble ions (Na⁺, Mg²⁺, Cl^–, K⁺, Ca²⁺, \(\rm{NH}_4^+, \rm{NO}_3^-, \rm{SO}_4^{2-}\)), and gaseous admixtures (SO₂, HCl, HNO₃, and NH₃). The characteristic particle size distribution functions are presented for different regions of the Kara and Barents Seas. It is shown that the levels of both aerosol turbidity of the atmospheric column (AOD) and the aerosol and soot concentrations in the near-water air layer were close to the long-term mean values in Arctic latitudes. The atmospheric turbidity during the period of measurements was noticeably affected by emissions of continental forest fire smokes. The contribution of smoke aerosol to, e.g., the mean shipborne-measured AOD at λ = 0.5 μm is about 44%.

Experimental data obtained in summer 2017 in the course of field hydrophysical studies on the variation in the index of light absorption by a yellow substance in the surface layer of Lake Teletskoye (Altai Mountains) are presented. The calculated values of the index of light absorption by a yellow substance (in natural logarithms) in the spectrum range 400–800 nm during the period under study were within 0.1–2.1 m^–1. The yellow substance concentration in Lake Teletskoye, found according to the optical method by the measured index of light absorption by the yellow substance, varied within 2.9–5.1 g/m³. To estimate the effect of light absorption by the yellow substance on the total attenuation, the relative spectral contribution of main optically active lake water components (yellow substance, suspended matter, chlorophyll, and clean water) to the spectral absorption index over the water body under study has been calculated. It has been revealed that the yellow substance makes the maximum contribution at all points (in total, 21 sampling points) of the lake.

The transmission spectrum of a holographic sensor (silver nanograins embedded in a polymer matrix) is shown to be well described by expressions for the Rayleigh light scattering and absorption by silver nanograins. The optical characteristics of the medium are determined in the Maxwell Garnett approximation. In the presence of a holographic structure, a dip appears in the spectrum. A possibility of obtaining the approximating curves depends on the approximation range. The spectra are well approximated both in the presence and in the absence of an interference structure. For different approximation ranges, the dip parameters coincide despite the values of the background parameter associated with absorption can differ significantly.

A four-channel photoelectric counter has been designed and manufactured for the measurements of saltating sand concentration fluctuations and size distribution function of particles with diameters >30 μm over desertified areas. The measurement results are given. It is shown that the vertical profile of the saltating sand concentration does not change on average in the altitude range from 3 to 7 cm over a desertified area in the neighborhood of the Volga. The distribution function of saltating sand particles over the desertified area is approximated with satisfactory accuracy by the lognormal distribution near the distribution maximum. Noticeable distinctions between the abovementioned distributions for large and small sand particles are observed.