The paper presents new approaches to taxonomy and classification of urban landscapes which are the most significant transformers of natural geosystems. Two groups of energy and material flows, i.e. transformed and autonomous, are identified in urban areas. The first include, for example, water consumption, final energy consumption and others. Autonomous flows that did not exist in the natural landscapes are, for example, the concentration of solid waste or the emission of greenhouse gases. Of 819 European cities with a population of over 100 thousand people, key cities for four UN statistical categories (over 5 million people; from 1 to 5 million people; from 500 thousand to 1 million people; from 100 thousand to 500 thousand people) were selected. Specific features of material and energy flows in the cities of foreign Europe and the European part of Russia with different population numbers were revealed. Cities of the first category are characterized by maximum specific indicators of all material and energy flows, both natural-anthropogenic and autonomous. In cities belonging to the second category the energy load on the territory is significantly reduced. For cities of the third category, the most acute geo-environmental problems are food supply, drinking water supply, disposal of domestic waste, and in the cities of the fourth category water and air treatment are the top priority. The parameters of material and energy flows transformation in urban areas and the calculated indicators of their environmental impact make it possible to establish classification characteristics for the refinement and development of the small-scale classification of urban geosystems.

The problem of smoking “epidemic” affecting the public health is highly actual in Russia for many years already. There are many detailed studies of smoking in Russia at the national level. However, at the moment there is no regionally representative survey of the Russian population on smoking issues. Unfortunately, the data of scattered regional studies do not solve the problem. The article is aimed at identifying regional aspects and patterns of smoking in the regions of Russia. The authors suggest an indirect assessment of how smoking affects the health and mortality of the population in various regions of Russia, by studying the regional characteristics of mortality from several diseases. For this purpose, a method of mathematical assessment based on the data on population mortality from diseases associated with smoking was developed and the regions were typified in terms of mortality associated with smoking, separately for men and for women. Based on the results, typological maps were constructed, and the regional differences in the structure of mortality from diseases associated with smoking were analyzed. A “northeastern gradient” of the effects of the tobacco epidemic in the structure and level of mortality was identified, as well as regional gender differences. If the consequences of male smoking, all other things being equal, are lower in the regions with a higher level of economic development and urbanization (excluding the regions of the Northern Caucasus), then for female smoking there are a number of violations of the regularity.

The paper discusses the impact of COVID-19 on the global tourism market. The brief overview of world pandemics and the comparison of SARS-CoV-2 and 1918–1920 Spanish flu are presented. Causes that could lead to the outbreak of a new coronavirus infection are analyzed.
The research propose an assessment scale based on official data of several international organizations such as UNWTO, UN, World Bank, IATA, WTTC, which allowed to classify countries into 4 types, according to the degree of COVID-19 impact on the international tourism. Information on such indicators as: the proportion of people infected with coronavirus; number of tourist arrivals in 2020 (compared to 2019); the share of tourism in the country’s national domestic gross product (GDP) for 2019; the percentage of tourism in the country’s national domestic gross product (GDP) for 2019; the share of tourism employees to the total number of country’s employment for 2019; lockdown restrictions and their duration; the existence or absence of international sanctions, was analyzed and systematized. The sample includes data on 181 countries.
The research has shown the vulnerability of states to the 2020 tourism crisis. The most significant possible risks due to the global epidemiological crisis belongs to countries where tourism is one of the systemically important sectors of the economy, and where a long entry/exit country ban or a full sanction list were imposed. Countries where tourism contribution to the economy was insignificant are the least vulnerable.
It has been determined that early and prolonged lockdown is an effective preventive measure in the fight against a new coronavirus infection. The study revealed the connection of tourism and COVID-19’s expansion around the world in March 2020. The results confirm the need for changes in the tourism sector as a response to the current social economic changes.

The ratio of different fractions of soil organic matter is seen as an indicator of the level of biological activity and could be used to assess the ability of soil to accumulate stable organic compounds, including the deposition of atmospheric carbon. The territory of the Tigirek reserve is an example of the vertical landscape structure invariant free of the past and present anthropogenic pressure. So, it is possible to reveal the features of accumulation of organic carbon of various oxidation states, which characterizes the ratio of labile and stable C pools of soil organic matter. It is shown that organic compounds in soils of mountain-steppe, subalpine and alpine belts are characterized by a higher proportion of moderately oxidized compounds (>28%) due to the predominance of herbaceous species in plant communities with a high content of cellulose and amino sugars in the litter. The soils of mountain-taiga landscapes are characterized by a higher proportion of hard-to-oxidize compounds (up to 60%) in comparison with the soils of mountain-steppe (up to 55%), alpine and subalpine belts (up to 27%), due to the predominance of tree species in plant communities with significantly higher lignin content in the litter. The share of hard-to-oxidize compounds in mountain-steppe and mountain-taiga soils increases with depth. At the same time, an increase in the proportion of difficult-to-oxidize compounds in mountain taiga soils is due to decreasing proportion of moderately oxidizable compounds (from 32 ± 9.1 to 25 ± 7.9%) with a relatively stable proportion of easily oxidized ones (about 23%). The opposite tendency is observed in mountain-steppe soils: a decrease in the proportion of easily oxidized fraction (from 26 ± 4.5 to 17 ± 4.3) against the background of a relatively stable proportion of moderately oxidized one (about 41%). The soils of alpine and subalpine landscapes are characterized by a stable ratio of easily (15–25%), medium (47–60%) and hardly oxidizable (19–31%) compounds of organic matter within the soil profile, due to low thickness of the soil profile and reduced microbial activity under acidic environment and unfavorable climatic conditions.

The oxygen isotope analysis is an important tool for the correlation of palaeogeographic events both within the Caspian region and while considering the Caspian history against the background of global climate changes. At the current level of knowledge, the oxygen isotope application as a palaeotemperature method for the Caspian region cannot be substantiated theoretically; such reconstructions for the Caspian Sea require a special approach. The necessary special studies have not been carried out yet in the region. A practical attempt to calculate palaeotemperatures for the Late Pleistocene – Holocene was carried out on the basis of oxygen isotope data from two boreholes in the northern part of the Caspian Sea. Ostracod shells are one of the most reliable indicators of palaeoecological parameters, so they were chosen as a material for isotope measurements. An attempt to solve several variations of the palaeotemperature equations with a certain degree of convention was made, by applying zero correction for the water background, calculating water background through salinity values and considering taxonomic and metabolic features of ostracod shells. The resulting water temperatures in the Late Pleistocene – Holocene were from 12.8 to 99.7°C in the first case, from 5.4 to 49.9°C in the second, and about 35.4–62.3°C during the Holocene in the third case. The calculated palaeotemperatures values are definitely overestimated and cannot be considered reliable. We conclude that the considered methods are not applicable for calculating palaeohydrological parameters in the Caspian region. The importance and necessity of the selection and introduction of special corrections is shown, since the changes in the isotopic composition of a closed reservoir undergo much more complex trends than in the ocean, and require a detailed study of all factors that can influence them.

The 2009, 2010, 2011, 2019 and 2020 hydrographs for the Protva River were separated into fast and basic components by the grapho-analytical method using the GrWat software package. The algorithm makes it possible to automatically separate the spring flood, baseline runoff, rain and thaw floods, depending on the characteristics of the water regime and uses the meteorological information of re-analysis. Separation of the runoff into two genetic components – groundwater and precipitation for individual days of the summer low-water period was performed. Isotopic separation was performed by the balance equation according to the δ18О values determined in river runoff and groundwater outlets. The oxygen isotopic composition of precipitation was taken as a monthly average δ18О of Moscow. For the summer low water, the algorithm divides the runoff into fast (atmospheric precipitation, surface runoff) and basic. The basic runoff separated by the GrWat algorithm is the total underground supply and consists of the groundwater itself and the suspended water. The assessment of soil component by the isotopic method does not include the suspended water. Thus, by using both separation methods together, it is possible to estimate the proportion of suspended water in the base runoff. The aim of the study was to establish the feature of the base flow of the Protva River and determine the amounts of groundwater supply, precipitation and water entering the main channel through the soil horizons (suspended water) for the summer low-water period. It was found that the contribution of the ground water component to the base flow is about 70–80%, and 20–30% of the base flow is formed by precipitation coming through the soil horizons. The study of the base flow formation and its separation in the GrWat algorithm is currently important for the catchments with irregular observations. The importance increases under the sharp interannual changes in water regime resulting from climate changes.

The problem of spring runoff regulation is considered basing on the knowledge of the regularities of its formation. The solution of this hot task is possible when identifying the role of natural factors affecting the flow. The aim of the work was to identify the role of snow reserves combined with other natural factors (the depth of soil freezing and its humidity) in the formation of meltwater surface runoff on agricultural land. The research was carried out on light chestnut soil in the dry-steppe zone of the Volgograd region. The methodological basis of our research was a system of methods used in erosion control, hydrology and other related sciences, adapted to the goals and objectives of the study. The complex interaction of snow reserves with other natural factors influencing the formation of meltwater surface runoff in the dry-steppe zone of the Volgograd region is revealed. It was found that when the soil freezes to a depth of less than 50 cm, the runoff forms independently of snow reserves. With deeper freezing, runoff depends on the interaction of snow reserves and soil moisture. If the level of moistening of the upper soil layer (0–30 cm) is below a certain limit (70 mm), the runoff is not formed even under its deep freezing. Regression equations for the relationship of runoff with water reserves in snow and soil under its freezing to more than 50 cm are suggested for various types of land (arable land, meadow, fallow) and arable land (autumn tillage, winter crops, perennial grasses, etc.). These fundamental studies allow taking a new approach to the assessment of the hydrological process and implementing the important applied research.

Parameters of snow cover and its individual layers were measured through the winter of 2015–2016 in the north-east of the Moscow Oblast. The aim of the study was to reveal the influence of local conditions of the spatial pattern and evolution of snow cover. Three sites with distinctly different vegetation and microtopography (field, forest meadow and mixed forest) were selected for the study.
During the maximum accumulation of snow the depth of snow cover was the least under the mixed forest, as compared with two other sites. Water reserves in the forest were by 50% smaller than at the forest meadow and by 40% smaller than in the field. Canopy intercepted snow fall down during wind, thaw, etc., and disturbed ground snow structure under tree crowns and at 1–2 m around them. Some snow layers were full of organic matter, thus reducing the surface reflectivity and increasing the intensity of snow melting. Deeper and much more

Baer knolls are usually elongated ridges of predominately sub-latitudinal orientation, which are widespread in the Northern Caspian region from the Kuma River mouth in the Kizlyar Bay at the western coast to the Emba River mouth at the eastern coast of the Caspian Sea. These ridges are not found anywhere above 0…+2 m a.s.l. beyond the limits of the Late Khvalynian transgression of the sea. The objective of the paper is to interpret the genesis of relief forms under study basing on detailed structure and lithology descriptions and dating of their material. Sediments of the Baer knolls usually consist of three lithological formations (LF1, LF2 and LF3) referring to the time interval of 21 to 11 cal. ka BP. Chocolate clays, as well as underlying marine sediments of a regression terrace and alluvium of rivers flowing to the Khvalynian basin were principal sources of material for knoll formation. The mollusk complexes of predominately brackish-water Didacna protracta, D. ebersini, D. parallella, D. parallella borealis, D. praetrigonoides, Dreissena rostriformis and Dr. polymorpha were identified in the deposits. Baer knolls were formed during the Late Khvalynian – Early Holocene transition. The knolls’ material cannot be attributed to the aeolian deposits because of their lithological, faunistic and geochemical features. The Baer knolls were formed at the lagoon bottom by the currents resulting from the Late Khvalynian basin water outflow through the Manych Strait. The landforms are analogues of river ripples and dunes appearing at the bottom of a turbulent flow, where the accumulation of sandy material and shell detritus took place simultaneously with the deposition of clay particles at the geochemical barrier as a result of coagulation under the mixing of lagoon brackish water and river fresh water.

The paper deals with the problem of landscape structure transformation under the influence of technogenic factors associated with the extraction of hydrocarbons within the territory of the Orenburg region. Technological systems of the Rostashinsky and Zaikinsko-Zorinsky deposits are chosen as objects of study. The main goal of the research was to study the dynamics of the geosystems of oil and gas fields in order to determine the direction and degree of destructive processes. For this purpose, the coefficients of horological, typological, and entropic diversity of landscapes were calculated using the geoinformation analysis of multi-temporal remote sensing data. As a result, ten numerical indices reflecting the structure of technogeosystems and six indices of landscape differentiation (Shannon entropy measure of diversity and complexity, heterogeneity of Ivashutina – Nikolaev, Odum, Glison – Margalef and Simpson) were obtained. Analysis of the morphological structure of the technogeosystem of the Zaikinsky and Rostashinsky fields showed that their dynamics is determined by the following key factors: increasing number of facilities related to subsoil use, due to the need to maintain the level of production at the old developed field; a sharp increase in the area of highly-mosaic fallow lands, due to weed successions; quantity reduction of agricultural hydrotechnical facilities (ponds), while maintaining and even increasing the area of technical reservoirs used by the oil and gas industry; reduction in the area of forest belts and increasing number of patches due to dead wood, shrubs and self-seeding; abandonment of settlements and decreasing population in the remaining ones, which also increases the number of contours. Higher degree of fragmentation of the technogenic landscapes of oil and gas fields, with an obvious decrease in the anthropogenic load, illustrates the restoration of disturbed inter-component and intra-landscape interactions due to positive feedbacks under weakening external influences.

Net migration at the municipal level in Russia varies significantly, both in positive or negative values and the size. The majority of Russia’s regional centres are experiencing positive net migration. Population size and migration attractiveness of a regional centre appear to be critical determinants for the positive spillover effect on the net migration in its suburbs. The paper aims to validate the hypothesis by the case of 63 urban okrugs (core areas) and their outer zones, which include 75 urban okrugs, 12 intra-urban territories of Moscow outside the Moscow Ring Road, 388 urban and 2973 rural settlements. The study is primarily based on the municipallevel statistics database of the Rosstat (BD PMO). The following indicators were used: administrative data on net migration for 2015–2019, population of the studied municipal units, the shortest centre-to-centre distance by existing roads from regional capital to each municipality in its suburban area (km). The values of average net migration rate were calculated and analyzed for 2015–2019.
The net migration rate for core areas averaged 4.3 ‰. Its value is higher in suburban areas at the distance of up to 40 km from the centre of regional capital. A steady migration decline is observed from a distance of 65 km. These boundaries extend further for metropolitan areas with a larger core. As the distance from the regional capital increases, both the number of municipal units with positive net migration and their share in the total population decrease.
Net migration values in the suburbs are higher than in regional capitals, and there are a few municipal units with an ultra-high, “explosive” rate providing for higher average values. Such areas are located in the immediate vicinity of the capitals and most commonly have relatively small “base” population.
The gap in net migration rate between regional capitals and suburban municipal units, as well as the spatial localization of positive growth rate in the suburbs, indicates the peculiarity of suburban processes in Russia. The nearest suburbs become a part of contiguous urbanized area of a regional capital beyond its administrative boundaries, providing the opportunities for extensive growth of a city.

The article deals with transfering passengers to the largest Russian cities of Moscow and St. Petersburg, which are also the largest transport hubs, both in railway and air traffic. We selected 62 cities or agglomerations which have a transport hub with year-round connections to Moscow and St. Petersburg. We also analyzed medium-and long-distance traffic flows mainly served by air and long-distance trains.
During the analysis, all connections of the selected nodes were grouped by their intensity depending on the number of passengers and by their percentage in the overall traffic structure. This made it possible to identify key differences between air and rail connections with Moscow and St. Petersburg. A large concentration of high-intensity and large-scale connections with Moscow was revealed, while the number of such connections with St. Petersburg is extremely small. A pronounced orientation of flows to the Moscow aviation and railway nodes was revealed, and the role of St. Petersburg was recognized as insignificant for the vast majority of cities.
Thus, the article states that, as of 2016, Moscow is the dominant factor in medium and long-distance transportation, both by aviation and by rail. The St. Petersburg node, despite its position in the structure of aviation and railway transport, practically does not have a territory gravitating towards it in absolute terms. The zone of relative gravitation was analyzed, which was estimated relative to the share of the population of the St. Petersburg agglomeration. An analysis of the aggregate gravitation zones for aviation and railway communication at medium and long distances revealed that, in general, St. Petersburg attracts the territories north of the line stretching from the south of the Pskov region to the north of the Kirov region.

The formulation and development of the discipline “Geophysics of the landscape” were based on the system approach, physical monism, method of balances and the trophic pyramid model. The wide application of measuring procedures and GIS-technologies at the beginning of the 21st century led to the accumulation of a huge array of data on the state of landscapes. The idea of the necessity of creating a physical and mathematical basis for the synthesis of the structure and functioning of geosystems was established. Since the beginning of the century physical and mathematical training made a considerable progress at the department of physical geography and landscape studies as a result of the establishment of such disciplines as “Instrumental base of landscape studies”, “Methods of analysis of spatial data”, “Modeling of geosystems”, “Geoinformation technology of landscape studies”, “Biogeophysics and biogeochemistry of landscapes“, “Mathematical morphology of landscape”, “Physical and mathematical principles of landscape studies” and others. Specific features of material presentation with the account of the knowledge of mathematics in the volume taught to the physical geography stream are considered. The way of introducing basic equations and models at the physical level of rigor is justified. New disciplines are discussed in brief. The link of systems methodology with the physical and mathematical essence of the landscape organization model is shown by the example of landscape-hydrological geosystems according to Horton and Straler. Practical value of the development of the direction for optimization of nature management and forest management is shown.