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It is quite difficult to determine the coordinates and magnification of reconstructed holographic image of a particle due to the lack of a clear geometrical-optical model describing the digital holographic process. To obtain magnified images in traditional optics and microscopy, lenses are usually used. In digital holography, such images can be formed without mechanical focusing and the use of optical components, for example, by controlling the divergence of illumination beams. This paper considers the issues related to the optimization of the optical scheme of digital holography that ensures lensless magnification of reconstructed images, justifies the feasibility of using a geometric optics apparatus in the design of such digital holographic systems, and describes their limitations. The results of the work can be used in the design and development of digital holographic microscopy systems, for high-precision reconstruction and analysis of holographic images of particles.

The main problem in solar energy is reducing optical losses due to light reflection from the surface of photovoltaic cells. This paper presents the results of a numerical study of antireflection properties of nanostructured silicon dioxide (SiO₂) coatings deposited on the surface of a solar cell. Two types of porous antireflection coatings are considered: a multilayer assembly of nanospheres and vertical air nanopores embedded in a continuous silicon dioxide layer. The light transmission efficiency is assessed depending on the thickness and structural design of the antireflection coating. It is found that the efficiency of solar energy conversion into electricity can significantly vary across different spectral ranges for the same antireflection coating type. It is shown that a coating made of vertical nanopores in most cases provides more efficient conversion of incident light compared to a porous layer formed by an ordered microassembly of nanospheres. The results are important for the development of more efficient solar cells and can be used to create anti-reflective coatings to improve the overall performance of photovoltaic devices.

Natural gamma radiation easily penetrates into the cells of a human body and destructively affects all structures causing a wide range of diseases. It also plays an active role in the atmosphere by participating in electrical processes and origination of ions, which affects cloud formation, precipitation, radiation balance, etc. There are very few measurements of the vertical distribution of gamma background over the Russian territory. This paper summarizes the results of aircraft sounding in 2003-2025. Based on the analysis of the long-term data, an average vertical profile of this parameter was calculated, which shows its nonlinear increase with altitude. In the surface air layer, this parameter varied within 0.03-0.25 mSv/h with the average over the period under study being 0.11 mSv/h. At an altitude of 10 km, the gamma background varied in the range 2.18-2.80 mSv/h, and the average was 2.35 mSv/h. The analysis of the latitudinal distribution revealed the belt 60-70° N with high gamma radiation values; the gamma background was lower to the south and north of that belt The data analysis has also revealed a weak annual variation with a maximum in November and a minimum in August, which is not typical for other atmospheric parameters. The results can be useful for choosing the range and uncertainty of developed radiation protection devices and means, as well as for assessing the probability of origination of radiative effects.

Stratospheric polar vortices, which form over the polar regions in late autumn, are large-scale cyclonic formations whose stability in the winter-spring period determines the scale and depth of spring ozone depletion. Using the vortex delineation method based on ERA5 reanalysis data, we studied the features in the vertical dynamics of the Arctic and Antarctic polar vortices in 2020 during their anomalous strengthening, which was accompanied by deep and prolonged ozone depletion in the Arctic and Antarctic. In particular, we examined the synchronicity in temporal changes at different stratospheric levels. The polar vortex breakdown in 2020 was observed from late spring to early summer spreading from top to bottom over 1-2 months. The dynamics of the Arctic polar vortex showed three peaks of activity, spreading from the upper to the lower stratosphere within a month. The dynamics of the Antarctic polar vortex clearly showed one peak of activity spreading from the upper to the lower stratosphere over a period of 2 months. The anomalous duration of the western phase of the quasi-biennial oscillation in the middle stratosphere has been proposed as a possible reason for the unprecedented strengthening of the polar vortices in 2020. The results can be used to assess the risks of increasing ground-level UV-B radiation which is dangerous for the biosphere.

The objective of this study was to determine an optimal radiation wavelength for scanning marine surface from air, which provides minimal radiation absorption, parasitic fluorescence, beam divergence, and scattering in the water column. These parameters depend on the probing laser type used. The research focused on water samples from the Black Sea collected 200 m from the shore immediately before the experiment and water samples stored for one year in light-protected hermetically sealed containers. For both sets of samples, the following were examined: scattering phase function, spectral transmission coefficients, laser beam divergence, particle size distribution of organic matter in the samples, and its effect on fluorescence spectra. Commercial semiconductor lasers with wavelengths of 450, 520, and 660 nm were used. The study shows a 450-nm laser to be optimal for underwater probing tasks since it exhibits the lowest radiation attenuation in the water column (0.5 dB/m), the smallest scattering spot, and minimal fluorescence. Organic particles do not significantly affect hydro-optical properties of seawater in the samples both immediately collected before the experiment and stored for one year. The results can be used in the design of above-water and underwater laser probing systems for marine surface analysis.

The results of a study of the intraseasonal radial growth of Gmelin larch ( Larix gmelinii (Rupr.) Rupr.) trees growing in a cryogenic larch forest on an anthropogenically modified site (the edge of a seasonal road) and on a natural forest site without anthropogenic disturbances are presented. Continuous measurements of radial growth during the season were conducted on experimental trees using DR-26A point dendrometers during the 2017-2019 seasons, which differed significantly in terms of weather conditions. The dynamics of intra-seasonal growth of the annual ring of an individual tree was characterized by a set of maximum daily values. Using the Pearl-Reed approximating logistic equation ( R ² = 68-99 %), the main phenological characteristics of tree ring seasonal growth for each tree were determined: the dates of the start and end of the growth season, duration of three stages of the growth season (in days), and the maximum growth intensity (mm/day) during the second stage. It was found that the tree ring width of the annual ring (TRW) is determined by the maximum intensity during the second stage of seasonal growth ( R = 78-97 %). In the anthropogenically modified site, the TRW is significantly wider than in the control area, regardless of the weather conditions during the season. The tree rings formed in the trees on the control site in 2019 was narrower than those in 2018, while they were wider in the anthropogenically modified site. The opposite trends are interpreted based on previously obtained relationships between radial increments and climatic factors (Benkova et al., 2024). The maximum intensity of tree ring growth during the season and TRW in the experimental sites are determined by weather conditions at different stages of xylogenesis. In the anthropogenically altered site, this is the period preceding the growth season (early May), when the weather conditions pre-determine the value of maximum intensity of tree ring growth associated with the stage of formation of new tracheids. In the control site, this is the later period (late May to middle June), when the weather conditions directly affect the process of new tracheid formation.

Trees are an important component of the urban landscape, a source of biodiversity and an important element in creating a comfortable environment. In urban conditions, trees are exposed to a wide range of stress factors that negatively affect their vital state and appearance. Regular observations are necessary to promptly assess the condition of the trees and their care. This is especially true for Arctic cities, where the range of tree stands is lower and their condition is more depressed. Combining visual and instrumental examination of a tree increases the accuracy of assessments, allows you to identify the volume of wood with varying degrees of destruction, assess the accident rate and make an informed decision on the appointment of support measures or removal. In 2024, the condition of tree stands in the Akademgorodok Park in Apatity, Murmansk Oblast was assessed using Siberian fir ( Abies sibirica Ledeb.). The categories of tree condition were determined using visual and instrumental methods using the Resistograph model R650-EA device, a number of health measures were recommended.

In recent decades, climate change has had a marked impact on ecosystems around the world. One of the most obvious effects of climate change is the marked transformations in stands of the upper forest limit. Studies show that climatic changes, particularly increases in mean annual temperatures and changes in precipitation regimes, are leading to significant shifts in vegetation zones. This paper is the first to analyze the dynamics of forest stands in the forest reserve Yenganepe on the western macro-slope of the Polar Urals. The variability of average morphometric indices of forest stands depending on altitude is shown. Despite the fact that individual trees of Siberian spruce ( Picea obovata Ledeb.), within the studied ecotone appeared in the early XIX century, the greatest changes in stand density occurred in the 30-60s of the XX century. The density of stands since the beginning of the XX century increased 12 times at the limit of individual trees distribution in tundra and up to 35-30 times in sparse forests and dense spruce forest. The dynamics of the studied stands differs significantly from the previously shown changes in the upper forest limit in the Subarctic.

A study of Scots pine ( Pinus sylvestris L.), Siberian spruce ( Picea obovata Ledeb.), and blue spruce ( Picea pungens Engelm.) tree samples in the parks of the city of Krasnoyarsk was conducted to select the most urban-tolerant forms. Morphological parameters of the stem and crown, as well as crown condition, were measured. Water-holding capacity of needles was used to assess tree drought tolerance. The most informative traits characterizing tree resilience to urban conditions, habit, and gas-cleaning capacity were selected for correlation analysis. Significant differences in the nature of multiple correlations between traits were found in the compared species within each park, as well as between samples of the same species from different parks across the city. A comparative analysis of correlation coefficients showed that the magnitude and direction of the relationship can serve as an additional significant criterion for selecting trees not only based on direct but also indirect traits. The results of correlation and discriminant analyses showed that tree breeding approaches should differ across the city, including due to the varying ages of tree stands. It is likely that, given increased air pollution and negative correlations between resistance traits and tree growth, a compromise between resistance and productivity is needed for urban tree breeding. Three evergreen coniferous species with the best traits were selected for further selection and use in urban landscaping.

The intensity and duration of vegetative growth of plants determines their biological productivity, which in turn depends on various environmental factors and the climatic conditions of the growing region. Therefore, identifying patterns of seasonal growth in coniferous trees is essential for determining the type and timing of measures aimed at increasing the productivity of forest stands, especially in regions of introduction. Since research data are scarce in the south of Western Siberia and are of interest for generalizing the results of introduction, the aim of this study was to identify patterns of seasonal growth of two- and five-needle pine species of the genus pines ( Pinus L.) within the residential area of the city of Omsk. This article examines the climatic conditions of Omsk during the seasonal shoot growth period of model trees and constructs a climatic diagram of the G. Walter modification according to Bagnoul-Gossen for April-June 2024 and 2025. A study based on data from the Omsk Hydrometeorological Center examined the dynamics of seasonal shoot growth in two-needle pine trees: mountain pine ( Pinus mugo Turra), Scots pine ( Pinus sylvestris L.) and jack pine ( Pinus banksiana Lamb.), and five-needle pine trees: white pine ( Pinus strobus L.) and Siberian stone pine ( Pinus sibirica Du Tour).