he natural zone is a basic concept of physical geography, reflecting the horizontal differentiation of the geographic sphere from the equator to the poles. Diversification of global geospatial data and the improvement of automatic computer classification methods offer new opportunities for the application of geoinformation analysis algorithms for delimitation of land units by zonal climatic features. The aim of the article is to apply geoinformation modeling to identify natural zonal boundaries, as well as to reveal limitations and problems associated with the uncontrolled classification. We use normalized indicators from the University of Edinburgh database (compiled on the basis of WorldClim data). At the first step, a set of significant climatic parameters necessary to model zonal-climatic groupings of natural complexes: annual temperature range, seasonality of monthly average temperatures, annual sum of average daily temperatures above 0°C, annual seasonality of precipitation, Thornthwaite aridity index and seasonality of potential evapotranspiration, was substantiated by the analysis of the main components. Further, uncontrolled classification of these parameters was carried out according to a different number of classes (15, 22, 72). To obtain a picture similar to the global naturalzonal differentiation, 22 classes are allocated in the model. New zonal-climatic boundaries obtained as a result of modeling were compared with the boundaries of natural zones on maps compiled on the basis of other methodological approaches using the case of Europe. In general new boundaries reflect major regularities of the belt-zonal differentiation of the land and could provide background for further typology of landscapes by means of geoinformation modeling. The study made it possible to identify principal methodological limitations of the geoinformation modeling of natural zones at the global and continental levels. Limitations of the cluster analysis for small-scale mapping of natural complexes are also associated with the complexity of choosing the optimal number of classes to obtain adequate visualization of the spatial structure of natural zonal systems, as well as with the “equal contribution” factor of all climatic variables used for modeling. It is shown that realization of automated modeling algorithms requires other geospatial data, in addition to climatic parameters (even in various combinations). The undoubted advantage of the described approach is the reproducibility of classification algorithms and the possibility to obtain the required degree of detail at the output, depending on specific tasks of particular geo-ecological studies.

The work is devoted to the assessment of the efficiency of green belts on road sections in the city of Irkutsk. For this purpose video surveillance of the composition and traffic intensity of vehicles was carried out during rush hours. Sound pressure levels were measured in areas with and without green spaces located along highways, using sound level meters. The obtained results were compared with the prescribed sanitary norms of permissible noise loads. Statistical characteristics of the noise level recorded in key areas were calculated. The analysis of the results obtained made it possible to reveal the excess of acoustic standards established in the Russian Federation, and the ability of investigated strips of green spaces to reduce the level of traffic noise by an average of 9,7 dBA. It was found that green spaces of the key areas under study are not sufficiently efficient to ensure the noise level that meets the established sanitary standards (55 dBA). Analysis of the data obtained during field measurements of the sound level at various distances from the road with different traffic intensity indicates the acoustic load on the territory exceeding the daytime hygienic standard by 15,2–23,8 dBA. It was found that traffic flows create a low frequencies noise level, but green spaces achieve the greatest absorption effect at high frequencies (above 1000 Hz). The noise generated on the carriageway propagates both to the first echelon of houses and deeper into residential buildings. Recommendations for reducing the sound pressure level to ensure the acoustic well-being of the population in residential areas adjacent to highways are proposed. Increasing the efficiency of green spaces throughout the territory subject to acoustic load should be achieved by placing multi-row tree belts near both noise sources and protected objects. A whole range of urban planning, engineering and administrative and organizational measures is necessary to reduce acoustic pollution of the environment by application of traditional and alternative methods on road sections.

The Hrazdan River water quality within the city of Yerevan was assessed by hydrochemical parameters using the Canadian Water Quality Index (CCME WQI) and ecological (regional) standards accepted by the Republic of Armenia for the functioning of ecosystems, fishery, and protection. Hydrochemical observations by 21 indicators were carried out twice a year (in low- and high-water periods) on 8 permanent stations from 2012 to 2018. The river water is classified into 5 quality classes by the water quality index values: high (95‒100), good (80‒94), moderate (60‒79), poor (45‒59) and bad (0‒44).
It is shown that water quality becomes poorer downstream the river: from water quality index values of 41 when entering the city (station Hrw-6), to 37 when flowing out of the city (Hrw-8). Water quality also deteriorated over recent years, from 47 in 2012 to 37 in 2018. By the coefficient of determination, the degree (amplitude) of standard deviations of indices (F3) and the quantity of standard-exceeding indices (F1) largely influence the ultimate result of the index making 82% and 80%, respectively. Water quality deterioration is caused mainly by mineral compounds of nitrogen (24%), chlorides (24), phosphates (23), sodium (14), sulfates (6), and heavy metals (2%).
The research results indicated that in general water in the Hrazdan River section within the city of Yerevan is of “bad” quality. It is anthropogenic factors, namely changes in natural hydrological regime, runoff control, heterochronous and uneven supply of pollutants entering from point and non-point sources, that determine the anomalous distribution of hydrochemical parameters by sampling stations along the urban section of the Hrazdan River in different years.
It is suggested to strengthen water quality control at Hrw-1, Hrw-6 and Hrw-8 stations when planning further monitoring studies, with an emphasis on determination of representative pollution indicators, such as ammonia, nitrite and nitrate nitrogen, phosphates, and indices of salt composition in water.

Since the electrical power output by converting total solar radiation using PV cells is low, it is necessary to identify areas with high solar radiation. However, low efficiency of PV panels (14‒18%) and the low intensity of total solar radiation on a horizontal surface require a large installation space to achieve a certain power level. Due to the high cost of installing solar power plants, a comprehensive systematic assessment of the geographic factors of a region is necessary to select the most suitable location. The reason we chos e Nakhichevan as a study area is that the radiation level is high compared to other regions of Azerbaijan (1220‒1699 kWh/m2 per year), and the annual duration of sunshine exceeds 2500 hours. Since the creation of solar power plants in regions with high values of the total radiation on a horizontal surface generally depends on technical, economic and environmental criteria, the areas corresponding to high criteria values in the model were thoroughly investigated using balanced comparison to identify suitable sites. The Analytical Process Hierarchy (AHP) model, based on Multi-Criteria Decision-Making (MCDM) methods, was used to identify suitable locations for solar power plants. In the first phase of the study seven criteria were analyzed to determine suitable locations, i.e. total solar radiation on a horizontal surface, slope gradient, land use, buffer distance from areas with high annual solar energy potential to residential areas, proximity to substations, highways and power supply lines. In the second stage the degree of accessibility and suitability of areas according to certain criteria was determined using the Weighted Overlay tool in Geographic Information Systems (GIS). As a result of the study, it was concluded that 9,5% (510 km2) of the area of Nakhichevan has high suitability, 12% (645 km2) ‒ average suitability and 24% (1290 km2) ‒ low suitability for placing solar power plants. The remaining 54,5% (2930 km2) of the region are unsuitable territories because of low radiation, high slope, the presence of protected areas, settlements and agricultural areas, and poorly developed infrastructure. Optimal locations are mainly in the southern and eastern parts of the region, as shown in the polygon shape on the suitability map.

GIS technologies increase the potential of socio-economic studies, i. e. they support collection, storage, processing and display of spatial data and documents related to a specific territory, as well as provide tools for system analysis of the situation, comparison and typology of territories and visualization of results. The range of sources for socio-economic research is steadily expanding; in addition to official statistics, “big data”, text documents, photographs, audio and video recordings, aerial photography, space photography, remote sensing of the Earth and other are available. GIS technologies make it possible to integrate various types of data characterizing a certain territory and visualize them in the form of layers on electronic maps. The possibilities offered by GIS make them modern tools for the complex analysis of regions and territories. Using these tools, the scientific community, business and government departments develop GIS applications for the comprehensive study of specific geographic objects, as well as analytical models and educational programs.
Significant GIS applications could be only implemented if there is full-fledged spatial data platform. Elaboration of the national spatial platform, starting with the development of standards for the interoperability of resources available at different government departments and other participating institutions, is the responsibility of government agencies.
The article reviews several GIS applications for social research functioning in foreign and Russian universities and research centers and briefly presents a Russian project to develop an open use platform for the study of socio-economic processes in the subjects of the Russian Federation using GIS tools. Foreign experience and inventions of the Russian scientific community may prove to be important for the promotion of geoinformation research methods in this country.

The article analyzes the processes of reducing numbers and reorganization of schools in rural areas of Russia for the period from the 1970s to 2019. Two large periods of rundown were identified. The Soviet one (early 1960s – late 1970s) is associated with programs of “regular” countryside transformation. The Russian one (from the mid ‒ 2000s to the present) began with the adoption of the Order “On restructuring of the network of educational institutions located in rural areas”. The quantitative characteristics of the process of closing schools in the RSFSR and Russia are shown. A comprehensive analysis of state documents, legal acts and orders shows their leading role in determining the directions and territorial projections of the ongoing school network transformation.
The relationship between the dynamics of school reorganization and the characteristics of rural settlement (in terms of their average population numbers) was analyzed for the Russian stage. In the period from 2002 to 2019, the most intensive reorganization of schools (reduction in the numbers from 83 to 40%) was characteristic of the least-populated regions of the European Center and the North-West and the Volga River region. Relatively stable network of villages in the European South and the disperse location of settlements in Siberia and the Far East contributed to a relatively moderate reorganization within these territories. The study showed general correspondence between the optimization solutions and the conditions of resettlement, but there are also visible deviations. It is noted that at the present stage the existing statistics overestimate the ongoing liquidation of educational institutions, since some schools are no longer considered after their transformation into a branch of the basic school (the process of reorganization). The author’s calculations show that after the formal completion of school restructuring program in 2010, the administrations of municipalities in most regions were forced to continue reducing and / or reorganizing the school network. This time the factors of “per capita financing” of educational institutions and measures for the implementation of state social policy (in particular, the level of teachers’ salaries) were complicating the functioning of small schools.

The Kamchatka Strait is the westernmost and deepest strait of the Aleutian archipelago. The harsh climate, the influence of permanent and seasonal atmospheric action centers, the passage of cyclones, seismic activity, tsunami hazard, and the complex bottom topography significantly complicates the investigation of water circulation in the Kamchatka Strait. Thus the goal of our research was to study the variability of water circulation in the strait during spring hydrological season (May, June) for the period of 1950‒2017 based on numerical modeling. The Ocean Data View software (ODV software) was used for statistical processing and graphical display of the data. The modeling results showed that the spring change of the winter atmospheric monsoon to the summer monsoon causes the transformation of current system. Against the background of cyclonic water movement prevailing during the whole year in the region of the Aleutian Island arc, the cyclonic activity in the Kamchatka Strait weakens in the spring, and anticyclonic gyres are formed, contributing to significant inflow of warm Pacific waters into the Bering Sea. Besides, during the above-mentioned season the Kamchatka current is not a single continuous flow of water masses. Instead, several hydrodynamic gyres of different signs are noted, indicating its vortex transitional structure. It is shown that the spring hydrological season is a kind of a threshold for the change from winter to summer water regimes, because in the spring synoptic season (March, April) the winter monsoon still prevails, and the average monthly air temperature is below zero. The differences in May and June show a gradual seasonal transformation of circulation schemes in the region, and, at the same time, a certain instability of hydrodynamic structures associated with uneven spring atmospheric processes.

For several decades the northeastern slope of the Borisoglebsk Upland has been a focal point for natural scientist interested in geochronology and Quaternary environmental reconstructions. A key reference section of the Upper Volga River region is a set of geological cores, exposures and excavations on the side slopes of the Puzhbol Gully system. The ORV section (Eastern Cheremoshnik Gully) was studied in detail applying the comprehensive analytical approach. We revealed an intermittent geological record of local transformations in the exposed sequence as follows: unstable infilling of a lacustrine depression by mineral and mineral-biogenic sediment during the Mikulin thermoxeric stage; biogenic and mineral-biogenic accumulation in waterlogged areas during the transition to subaerial deposition under periglacial environment of an initial phase of the Early Glacial; discrete erosion and accumulation with associated slope processes during Pleniglacial; and just an episode of colluvial deposition attributed to a cold Holocene stage. Hiatuses in the paleogeographic record were identified for several periods of different duration, at least for the Mikulino thermohygrotic interglacial stage and for significant intervals of the Late Glacial and the Holocene, mainly because of the occasional activation of erosion processes. Stratigraphic discordances exposed in the ORV section have shown its deficiency as a reference one for the reconstruction of the Late Pleistocene and Holocene environmental history of the region. Nevertheless, we can use fractional particle size distribution of the layers formed by sedimentation of lacustrine depressions and erosion cuts as a sensitive indicator of the local Late Pleistocene lithodynamics.

Impact of the implementation of large coal mining projects on socio-economic changes in rural areas is investigated using the example of the Altai district of the Republic of Khakassia, where new coal mines developed in the 2010s. The study was carried out on the basis of materials collected during an expedition to the Altai region in August 2021, supplemented by open statistical data of regional and republican departments and the Russian Federal State Statistics Service. It is shown that direct economic effects of the activities of coal mining companies, such as the growth of employment, wages and tax revenues, concentrate in the settlements located in the immediate vicinity (within 20–30 km) of the coal mines. At the same time, greater effects of developing new coal enterprises in the Altai district are pronounced outside its territory. Development of the coal industry is a factor curbing the population decline in rural settlements of the district, however the bulk of the employed and contractors, as well as educational centers that train personnel for coal industry, are located in nearby cities, i. e. Abakan and Chernogorsk, thus negating the stimulating effect on the dynamics of economic development of the studied municipal area. Employment, income increase and financing of social projects are concentrated mainly in the district center, as well as in the settlements closest to coal mines or having coal mining specialization. They also experience a principal transformation in the population lifestyle, i. e. the reduction of livestock at personal subsidiary farms. The only type of effects from coal mining that is distributed relatively evenly across the territory of the district are social budgetary effects, namely financial assistance from coal companies for the implementation of local social projects in the municipality, which is distributed by the district administration, in particular to its peripheral territories. At the same time, there is no significant negative impact on agriculture of the district. During the 2010s its main indicators are growing, but a kind of territorial transformation took place when the main enterprise of Arshanovo settlement “moves” to another one farther from coal mines.

The sex ratio is an important component of the age-sex population structure and an integral demographic characteristic. Formation of the sex ratio is one of the key demographic issues in turbulent Russian history of the last century. Nevertheless, the territorial differentiation of sex ratio and various determinants affecting it, especially at the local level, has received little attention from Russian scientists. The article examines spatial patterns of the sex ratio in Russian municipalities during 2016–2020. The sex ratio was considered for the entire population, as well as for particular age groups, namely 0, 14–15, 18–19, 35–59, and 60+ years. The article is a first detailed study of the spatial differentiation of sex ratio by age at this level of administrative division in Russia. Methods of demographic and cartographic analysis were used in the study, and the situation in Central Russia was considered in detail.
The results of the study showed that the sex ratio at different ages depends on the rank of a territory in the central-peripheral hierarchy, while the distribution of the institutional population is the main extraterritorial factor. The sex ratio registered at birth changes under the influence of migration and natural population chan ges. The principal determinant at young ages is different mobility between sexes (higher intra- and inter-regional migration of women), resulting in a disproportion of the ratio in favor of women in central municipalities, and in favor of men in the periphery. In later life higher male mortality in peripheral territories gradually neutralize the differences in sex ratio between municipalities formed by migration. In addition to above-mentioned factors, other determinants, such as ethnic composition of the local population and cohort effects, may also affect the sex ratio.

Major changes in global geoeconomics and geopolitics significantly impact the development of border regions, which are active participants of the international trade because of their geographical location. Sanctions and restricted access to some international markets alter traditional international economic relations as well as the geographic focus of trade flows in border regions. Their export and import openness transforms the prerequisites for the development of regional industries and the entire economy.
The paper analyzes the international trade flows of the exclave region during 2012–2020. The approach suggested by the authors is applicable to any Russian region actively involved in international trade. The study uses the theoretical and empirical typology of international trade flows by the criteria of changes in their territorial concentration and value added. The typology of international trade flows is based on their involvement in regional industries. The influence of geography on the identified typological groups is analyzed at various spatial levels: I – continental; II – groups of countries; III – individual countries and regions.
The typology allows for assessing the prospects of each industry under consideration for maintaining or increasing their added value under changing geopolitical situation.

The formation of increased turbidity zones in tidal estuaries is an important factor influencing their hydrochemical, hydrobiological and hydroecological regimes. The authors solved the problem of identifying regularities for processes in the estuarine areas of small rivers flowing into the tidal sea and analyzed the features caused by morphological patterns and the tide magnitude. Expeditionary studies of 2015‒2019 in the estuarine areas of the Kyanda, Tamitsa, Syomzha, Pyia and Chyosha rivers exposed that higher turbidity, or concentration of suspended sediments, comparing with adjacent riverine and marine water masses, is characteristic of the areas of reversing tidal currents. The sediment concentration was determined using the gravimetric method by filtering samples taken synchronously with recording the flow parameters. A wide range of turbidity fluctuations occurs depending on the tidal cycle phase, the fresh and salt water mixing, the geological and geomorphologic structure of the seashore and river channel pattern, as well as the weather conditions. The highest maximum turbidity is during the open channel season in macro-tidal estuaries, for example, 4,32 kg/m3 in the Chyosha River estuary and 2,66 kg/m3 in the Syomzha River estuary. The maximum turbidity in the Kyandy and Tamitsa rivers meso-tidal estuaries is lower by an order. Regular changes in turbidity have been traced during the tidal cycle, when the maximums of flood flow velocity and turbidity occur almost simultaneously. Increased turbidity could be facilitated by wind waves on the seashore, which entrains bottom sediments into motion, as well as by intense rainfall over the extensive tidal floodplains before their inundation. During the ice cover season synoptic factors become less important, although the tidal ice hummocking and ice contact with the bottom sediments could result in episodically higher local turbidity. As a rule, the minimum turbidity has been noted just before the beginning of the flood when fresh river water runs off. Vertical turbidity stratification in small estuaries during flood and ebb currents is practically non-existent due to intense turbulent mixing; however, under high slack water during the periods of current direction change it could appear in river pools where suspended particles settle.