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The results of numerical simulation based on the Mie theory of the superresonance effect in a dielectric sphere with a low refractive index are presented. Water was used as the material of the mesoscale sphere. It is shown that not only the previously studied weakly dissipative mesoscale spheres made of a material with “medium” (~ 1.5) and high (> 2) refractive indices, but also with a low one (~ 1.3) support the high-order Fano resonance effect associated with internal Mie modes. In this case, the intensities of resonant peaks for both magnetic and electric fields can attain extremely high values on the order of 10⁶-10⁷ in the vicinity of the poles of a water droplet with a Mie size parameter of ~ 70.

The paper presents the results of complex experimental studies of gas impurities and the vertical structure of aerosol in the atmosphere over Lake Baikal in September 2021, using the research vessel (RV) "Academician V.A. Koptyug". Measurements of gaseous impurities in the near-air layer were carried out using local control means - chemiluminescent gas analyzers. The sounding of aerosol fields was carried out using a multi-frequency polarization aerosol-Raman lidar "LOSA-A2". Compared to previous expeditions, in 2021, low concentrations of gaseous impurities and aerosols, close to the background ones, were recorded. The analysis showed that the main contribution to atmospheric pollution was made by nearby local sources located near the coastal zone of the lake.

The approbation results for the algorithm of detecting specularly reflecting layers in high-level clouds based on passive satellite data are presented. We consider cirrus clouds with an optical thickness of less than 5 and a top height of more than 8300 m consisting of horizontally oriented ice crystals, observed over the territory of Western Siberia from 2006 to 2007. The technique for detecting specularly reflecting layers in high-level clouds is described and the statistical analysis of their parameters is performed on the basis of spectroradiometer MODIS satellite data. We discuss the seasonal and latitudinal properties of the parameters of considered clouds over Western Siberia..The typical values of the area, top height, reflection ratio, and effective emissivity of specularly reflecting layers over different latitudinal zones of the target region were estimated for the first time.

In this work, the long-term series of vertical stratification of aerosol in the stratosphere are processed and analyzed with the use of the scattering ratio as an example, as well as the vertical distribution of aerosol scattering coefficients at a wavelength of 532 (altitude range 15-50 km) over Tomsk. The experimental data were received from regular measurements at the lidar station of Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, in 2010-2021. On the basis of the accumulated experimental material, regional features of the intra- and interannual variability of the stratospheric aerosol in Western Siberia were revealed. An optical-aerosol model of the atmosphere is suggested for this region, more adequate to actual conditions are compared to existing ones.

Possibilities of wind speed measurement in the atmospheric layer from 10 to 20 km with a ground-based pulsed coherent Doppler lidar (PCDL) operating on molecular light scattering are numerically studied. Requirements for the parameters of PCDL with sounding radiation wavelengths of 1 and 2 mm for receiving reliable information about the wind speed and direction in the atmospheric layer under study are determined in numerical experiments.

The reasons are found for a decrease in the sensitivity of a TROA (time-resolved optoacoustic) detector in spectrometers with pulsed lasers and of a non-resonant OA detector in spectrometers with cw lasers when buffer gas nitrogen (air) is replaced by hydrogen in mixtures with an absorbing gas. In the first case, the reason is the high speed of sound in hydrogen at an insufficiently wide working frequency band of the microphone. In the second case, the reason for the loss of sensitivity is the low dynamic viscosity of hydrogen, which results in faster pressure equalization in the pre- and behind-membrane volumes of the OA detector chamber for a light pause as compared to heavier molecular gases. Therefore, the amplitude of an OA signal at the modulation frequency of the cw laser radiation increases in proportion to the dynamic viscosity of the gas.

The mixed moments of wind vector components on the turbulent and meso-gamma scales calculated from experimental data obtained in the surface air layer at an altitude of 10 m are compared. The statistics of mixed moments for several months in different seasons of 2021 is presented. The dependence of mixed moments on the wind velocity and temperature stratification in the surface air layer is briefly analyzed. The values of mixed moments formed by the wind field components on the meso-gamma scale are comparable with those formed by the mixed moments of turbulent components of the wind vector.

The simulation results the radiative forcing of smoke aerosol (RFA) at the boundaries of the atmosphere are considered depending on the photochemical evolution of its organic component, illumination conditions, and underlying surface types (water, mixed forest, and snow/ice). An increase in the albedo of the underlying surface and a decrease in the aerosol optical depth can lead to the transformation of the cooling effect into heating at the top of the atmosphere. An increase in the absorbency of aerosol particles is the cause of an increase in RFA at the top of the atmosphere, which is most significant over snow/ice surfaces, while at the bottom of the atmosphere, RFA decreases. As the solar zenith angle increases, the absolute value of RFA decreases as the smoke plume propagates over weakly reflecting surfaces, but with an increase in the albedo of the underlying surface, this dependence transforms into a nonmonotonic one. It is shown that neglecting the transformations of the optical characteristics of organic aerosol can lead to overestimation or underestimation of the radiative forcing of the aerosol at the top of the atmosphere by several times (by several tens of W/m²), and also cause an error in determining the RFA sign.

With an increase in energy consumption, more and more attention is being paid to nontraditional energy, including natural resources of thermal springs. Along with the problems of using thermal waters, their search is an important task. The experience of analyzing maps of plastic relief for the detection of thermal springs, obtained by using the example of the south of Kamchatka, is presented. Linear and ring-shaped zones of tension of the Earth’s crust were identified according to the maps of the relief plasticity. Of particular interest are the intersections of linear and ring structures. There arise zones of increased fracturing of rocks, within which active and extinct volcanoes and thermal springs are located. A map of promising sites is presented, the development of which in the near future will make it possible to solve the problems of energy consumption in an environmentally safe way, expand the geography of tourism and spa balneology. This will give an impetus to the development of the entire region as a whole. The experience of analyzing relief plastic maps in order to detect thermal springs can be applied throughout Russia in the future, including when searching for ore deposits.

The problem of forest degradation caused by high growth rates of population is considered by using the Anuppur District (India) as an example. It is shown that the study area is faced with a significant reduction in the forest area due to a rapid population increase and an enhancement of economic activities. In 1981, the area occupied by forests in Anuppur was estimated at 129 885 ha (the area of the district totaling 374 671 ha), whereas it decreased to 76 448 ha in 2011. For the same period the population increased from 418 731 to 749 237. We identified a feedback between the population and the status of forests in the study area. Many kinds of economic activities (agriculture, construction of settlements, motor roads and railroads, engineering structures, development of mineral resources in the forest zone, etc.) are carried out in an unsupervised manner, which leads to a reduction of forest areas, loss of biodiversity of forest ecosystems, and to other ecological problems. Recommendations are made for improvement of forest management in order to increase sustainability of forest ecosystems as well as to meet the needs of the economy and population of the district for various forest resources.