查看更多>>摘要：On the basis of high-precision astronomical ephemeris with a high spatial and temporal resolution, the insolation of the Earth at the upper boundary of the atmosphere was calculated for the period from 3000 BC to 2999 AD. The differences from the earlier calculations of insolation are associated with the initial astronomical data and new calculation algorithms. In our calculations of insolation, the time interval of 5999 years and the entire surface of the Earth have been covered in detail. The Earth is not identified with a sphere, but is approximated by an ellipsoid. Previously, calculations of high-frequency variations in insolation were performed for individual parallels (in space), and in time for four or five separate points of the year (equinoxes, solstices and, sometimes, points with a geocentric longitude of 120 degrees). We have calculated insolation for the surface of latitudinal zones at 1 degrees latitude and time intervals equal to 1/360 of the duration of a tropical year (approximately a day). Correlation analysis of the total mass balance of alpine glaciers (for the period from the balance years 1948/1949 to 2009/2010) with summer and winter insolation and summer, winter and annual insolation contrast of the northern hemisphere, which in a summarized forms (by regions of heat source and sink) reflects long-term changes in the meridional insolation gradient. It has been determined that the long-term variability in the total mass balance of alpine glaciers on average (for glaciers covered by balance observations) is accounted for by the trend at 94.3%. The trend to a reduction of alpine glaciers by an average of 90.6% is determined by the annual insolation contrast, which reflects an increase in the meridional heat transfer, as determined by an increase in the meridional contrast of radiant energy (on the Earth's surface, excluding the atmosphere). Based on the close correlations determined by using a regression model, a forecast of the total mass balance of glaciers up to 2050 AD was made, which indicates a catastrophic development of the degradation of the modern glaciation of the Alps.
查看更多>>摘要：The use of diverse, multi-temporal satellite space information has become the main approach in investigating the current status of mountain glaciers. We have accumulated large archives of satellite images of snow-glacial systems on Earth with different spatial resolutions over the past 50 years. Together with the previously created topographic maps displaying glaciers, glacier catalogs, special maps, and atlases of ice and snow, they provide data to determine changes in areas, lengths, volumes, and altitudes of glaciers during the current climate warming. In 1986, the World Glacier Monitoring Service (WGMS) was founded to monitor glacier fluctuations in different regions of the Earth. However, the number of observation sites is limited. The Global Ground Glacier Observing Network mainly includes those glaciers where we previously conducted ground-based studies of glacier front fluctuations, mass balance measurements, measurements of meteorological parameters, ice flow velocities, and ablation features. To identify regional differences, different altitude and plan locations, the influence of permafrost, and the background landscape environment requires that data on a larger number of glaciers be analyzed. Therefore, groups of researchers from Irkutsk and Beijing began to study the dynamics of glaciers in the inland regions of Eurasia within the framework of international projects. Several glaciers were selected in the mountains of the south of Eastern Siberia, the Mongolian Altai, and the eastern part of the Tien Shan. We recorded current glacier fronts and their elevations. The lengths and areas of glaciers in the early 1970s and early 2000s and their current state were determined. In recent decades, some connections between the dynamics of glaciers and changes in meteorological parameters have been revealed.
查看更多>>摘要：This paper examines the transformation of irrigated lands in regions of Russia over the course of a long period. In 1990-2018, the area of irrigated lands decreased nationwide from 6.2 to 4.7 million ha. In some constituent entities of the Russian Federation, the area of irrigated lands decreased by 4-14 times; while in two of them, it increased by 35-40%. In 2018, 735 000 ha (16%) of irrigated lands were not used in agriculture, primarily due to soil salinization and waterlogging; back in 1990, the share of unused lands was only 3.7%. It is concluded that agricultural use of idle irrigated lands should be resumed as soon as possible to enhance food security and increase exports of foods and agricultural raw materials. The ongoing transformations in the structure of irrigated agricultural lands in Russia are not that perceptible at the federal level; however, in some regions, they are quite noticeable. The share of forage crops in irrigated crop rotation systems should be increased to enhance soil fertility and boost the production of forage and livestock products. A steady deterioration trend in the ameliorative condition of irrigated lands has been observed in the country in recent decades. An especially unfavorable situation is noted in the Northwestern Federal District. The area of lands that require capital improvements to raise the technical level of their irrigation systems has increased dramatically. The area of actually watered irrigated lands has decreased from 4.9 million ha in 1990 to 1.4 million ha in 2016. Concurrently, high-efficiency drip irrigation systems are rapidly developing. Domestic manufacturers and joint ventures should boost the production of drip irrigation systems in Russian regions. This study presents data that indicate a revival in the production of domestic sprinkling equipment that is not inferior to foreign counterparts and costs much less.
查看更多>>摘要：Experimental investigations were made into the basicity-acidity indices (pH) and soil biochemical activity (SBA) in the industrial city of Ust'-Ilimsk in conditions of Eastern Siberia. A cartographic representation of the distribution of values of integral indicators of soils in the city is presented for the first time. The significance of the method of mapping urban soils that are experiencing urbanization and technogenesis is emphasized. The investigation was made by using the express method of determining the soil biochemical activity. In addition to this indicator, pH conditions of soils were identified. The study encompassed the main functional zones of two parts of Ust'-Ilimsk: the Old Town (Levoberezhie) and the New Town (Pravoberezhie). The neutral and weakly alkaline soils are of widespread occurrence on the territory. The pH values vary from 7.4 to 7.8; in the control soils, they vary from 6.3 to 6.9. A significant area of the city (43.9%) is occupied by weakly alkaline soils. The level of soil biochemical activity permitted us to categorize the soils as active and very active. The proportion of very active soils makes up 32.9% of the total territory of the city. This indicates a trend of ecological regression, namely a loss of a biogenic element, nitrogen. The study revealed trends of a weak but positive dependence of SBA on pH. The coefficients of approximation are positive and vary, according to the zones of the city, from 0.2 to 0.5. The absolute and relative distribution of the areas with pH and SBA values is shown. A comparative analysis of data revealed a difference of the Ust'-Ilimsk soils from the soils in other cities of the Angara region.
查看更多>>摘要：This study discusses the environmental consequences of a major landslide that occurred on the shore of the Bureya reservoir in December 2018, for the first time in the winter period; it was the largest such phenomenon in Russia over the last decade. Toxic organic substances present in water and aufeis in the landslide impact zone and after the collapse of the dam composed of rocks were analyzed. A comparative analysis of aromatic compounds contained in water in the vicinity of the landslide body prior to and after blasting operations and in the newly-built artificial canal was performed using gas chromatography. Predominant organic components present in the water included a number of toxic substances (e.g., methanol and methylated benzene derivatives); after the drainage of the water through the landslide body, concentrations of these substances increased. Many volatile organic substances have a natural origin and could be contained in the pore space of rocks. After the blasting operations, the content of hexane and isopropyl benzene in the water of the artificial canal increased. It has been established that rock grinding caused by the landslide and by the blasting operations significantly affected the composition of volatile organic substances. Rock watering, thawing, and freezing; decomposition of plant residues; and transformations of detonation products of explosives initiate various biogeochemical processes in the pore space; aromatic compounds formed as a result of such processes pose environmental risks to the reservoir ecosystem.
查看更多>>摘要：Based on analyzing bathymetric material obtained in different years by using high-precision geophysical equipment featuring multi-beam echo sounders, the main bottom relief features of the South, Middle, and North basins of the Baikal depression have been considered. It has been established that ridge-ravine forms and canyon valleys are well developed on the underwater slope of all depressions. The valleys of the canyons of the Middle and South basins reach their maximum maturity, which is associated with a longer history of the evolution of these basins. The canyon valleys are highly sinuous there, which is associated with the peculiarities of the underlying substrate and fault tectonics. The canyons of the western side of the Baikal depression are predominantly tectogenic in origin, are short, and show a significant steepness of the longitudinal profile; their valleys are mostly rectilinear. The underwater slope along the eastern coast of the North basin and its abyssal surface are complicated by a set of glacial landforms: moraine swells and fan cones formed by turbidite flows during interglacial periods. On the coast, they are continued by very extended swells of lateral and stadial moraines. Tectogenic scarps are widespread in the lower parts of the underwater slopes and usually run parallel to the coastline. It has been established that the flat-convex surfaces of the deltas, which sometimes reach the abyssal surface of the lake, are a very characteristic form of the sloping relief of the South basin. Numerous outcrops of Miocene-Pliocene limnic sediments on the eastern coast of the Middle basin, and the nature of their spatial arrangement suggests that the sedimentary strata of the underwater slope of this basin may be of the same age and be genetically homogeneous with terrestrial strata, which are Miocene-Pliocene in age. Similar deposits of the Tankhoi field on the southern coast of the depression also extend far into the water area of the lake, which supports the existing points of view about the similar history of the development of the South and Middle basins.
查看更多>>摘要：To analyze the recreational development of the coast of Lake Baikal, a map of the contemporary landscape structure on a key site (Goloustnoe coast) has been compiled; based on this map, the main factors of natural attractiveness for the development of the tourism industry have been identified. Considering the economic and geographical patterns of the region combined with its landscape and recreational potential, historically formed and preferred types of recreation activities have been determined. With a view to reveal environmental problems, the main directions for recreational activities have been identified that have the greatest negative impact on the functioning of landscape complexes in the area. It has been pointed out that a low level of ecological culture of vacationers is frequently the chief cause of an intensification of adverse events. Therefore, the risk of crisis situations is borne not only by tourists, but also by the operation of recreational infrastructure facilities. Geoimages obtained by processing images taken with a drone helped to identify centers of greatest environmental stress, as well as present quantitative parameters characterizing the extent of the negative impact. Having considered the high degree of sensitivity of landscape complexes to anthropogenic impact, ecotourism-oriented leisure activities have been proposed that can not only reduce the burden on the part of recreational activities, but also increase the level of environmental morality. Besides, the authors have provided the examples of recreational facilities, already existing on the Goloustnoe coast of Lake Baikal and methods of their management, guaranteeing environmental stability, which is necessary in the implementation of measures aimed at sustainable development of the Baikal territory.
查看更多>>摘要：The features of the suspended sediment load along the 200-km braided channel of the Lena River from the city of Pokrovsk to the Aldan River mouth (upstream of the Aldan braiding) are described in detail (30-m resolution) based on water-sediment concentration modeling, using the collection of Landsat images for the period of 1992-2018. It is shown that large anabranching river reaches correspond to changes of the system of sediment transport and accumulation, manifesting themselves as the predominance of the occurrences of positive (increase) or negative (decrease) Delta S-0 values (where Delta S-0 stands for suspended sediment-concentration budget). The conditions of a longitudinal decrease in suspended-sediment concentration along the braided reach of the Lena River are characterized by high water discharges (>20 000 m(3)/s) and are associated with sediment accumulation in riffles and floodplain areas. It has been revealed that a significant role in the longitudinal decrease in water-sediment concentration is played by lateral floodplain branches, which accumulate a part of the incoming suspended sediments and exert a dilution effect on the sediment flow downstream of the confluence with the main channel. Cases of a longitudinal increase in the water-suspended sediment concentration are typical for lower water flow rates (<20 000 m(3)/s) and are related to increased bank thermal erosion in summer and erosion of riffles during a low-water period. A combination of the grid of suspended-sediment concentration, velocities, and channel depths with a 30 x 30-m resolution (more than 20 000 cells) for low-water conditions revealed a dependence of the local suspended-sediment concentration on the transporting capacity of the flow, which was determined for particular verticals. A correspondence between the regime of certain reaches in different phases of water regime is observed. It indicates the mutual influence of the directedness of mass exchange and channel morphology. The transformation of distribution systems of suspended sediments may be interpreted as one of the self-regulation mechanisms in the channel system. Complex systems of sediment flow distribution along the channel of a large river reflect the opposite directions of erosion-accumulation processes caused by bends in the longitudinal profile.
Namzalov, B-Ts B.Taisaev, T. T.Budazhapov, L-Z, VNamzalov, M. B-Ts...
9页
查看更多>>摘要：This article summarizes the material from geobotanical and biogeochemical studies into the vegetation of the Irkut River valley in the spurs of the Kitoi Goletzes of the Eastern Sayan Mountains. An analysis is made of the features in spatial structure and the floristic and phytocenotic diversity of vegetation of cryo-steppe open woodland, taiga larch forests and meadow-bog complexes in the high-mountain valley of the Irkut River. It was found that the landscapes of the subalpine cold forest-steppe represented by a combination of sparse herbaceous (ptylagrostis-cobresia, fescue) larch forests, shrub groups with the involvement of Spiraea alpina, Betula rotundifolia, and Dasiphora fruticosa, and communities of cryophytic steppes typically occur at altitudes of 2000 m above sea level. The latter constitute the original element of the forest-steppe, which is often dominated by the endemic fescue Festuca komaroviis. The dominant taiga vegetation is dominated by larch forests. Larch forests are dominant in the composition of prevailing taiga vegetation. These are mainly lingonberry-rhododendron-lichen larch forests and larch forests with lingonberry moss-lichen communities. The communities of subalpine larch forests of the Il'chir tract showed anomalies in the gold contents in samples of fruticose lichens, that is, reindeer lichen. The gold content in lichen samples varies from 0.1 to 0.8, and in some places it reaches 1-3 g/t. In general, in the Sayan alpine landscapes, gold-sulfide vein zones are known to occur in rocks of the Paleozoic volcanogenic-terrigenous formation and at its contact with the carbonate formation. Along the slope, gentle watershed ridges overgrown with taiga larch forests are interspersed with narrow hollows of cryogenic subsidence with the occurrence of boggy willow forests, sedge-cobresia, and ptyagrostis meadows with Dasiphora fruticosa. Only at the foothills, on bedrock terraces with outcrops of rocks of the Paleozoic carbonate formation, communities of the cobresia-fescue alpine steppe are formed.
查看更多>>摘要：This article discusses recent changes in the development of industrial production in Irkutsk oblast from 2010 to 2019. Industry is the basic component in the economic complex; it provides about half of the region's gross added value and is characterized by a multi-sectoral structure formed primarily on the basis of using natural resources and cheap electricity. It is pointed out that in the last decade, a significant change in the structure of industry has led to a structural simplification of its sectoral composition with a significant shift toward the raw materials sector. Cities remain the leading centers of concentration of the manufacturing industry. The grouping of municipalities according to the level of industrial development was carried out according to the available statistical data: the calculated share of the employed in industry and the volume of shipped products of large and medium-sized organizations. On the basis of their ratio, groups of regions with intensive development of the extractive industries, primarily the oil and gas sector, as well as territories in which the industrial profile was formed in Soviet times but underwent transformations under the influence of changes in the market, were identified. A group of regions with very low industrial development has been identified, in which economic activities are mainly related to agriculture, logging, transport, and tourism. It is shown that some of the municipalities have changed their position in the groups when compared to 2010. The rest of the composition is relatively stable. It was found that in the first and fourth groups a change in priority in the development of types of economic activity occurred, whereas the second and third groups show a change in their proportions. Large business contributes to the extremely uneven distribution of investments across the oblast in the implementation of investment projects.
NSTL
Springer Nature