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Atlas

Trends rainfall map

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Climate change

The ratio of a linear trend, which is determined by the least square technique and characterizes the average rate of the climatic variable corresponding to the trend, was used as a measure of intensity of climatic changes within a specified period of time.

Annual temperature of the lower layer of air is used to describe the current climatic changes. The physical sense of this climatic characteristic is determined by an almost linear dependence of longwave radiation coming from the top border of the atmosphere on the temperature of the lower air layer. Given this dependence, the assessment of the indicated temperature is largely analogous to the estimation of the average outgoing longwave radiation, which can be used to determine the speed of heating or cooling of the Earth's surface.

Annual temperature trend values in 1961-2008 were positive and ranged from 0.24° to 0.52° C/10 years, which is an order of magnitude higher than similar ratios calculated on the average for the Northern Hemisphere. Maximum values of the trend are observed in the north of the study area. One of the centers is located in the Barguzinsky reserve. This area (on the northeastern coast of Lake Baikal) is also interesting, as unlike other weather stations it has the same high trends throughout the year. The majority of these locations is characterized by the annual variation of the coefficients describing the linear trend of air temperature, with a peak in February and a minimum in the summer months. July has an asymmetric distribution of trend values. Although they are all statistically significant, their maximum clearly shifts to the territory of Zabaikalsky krai. The foothills of the Khamar-Daban (the Khamar-Daban station) and the upper Lena river (the Kachug station) can be called the local areas of minimal trends during all months of the year.

 

A quite different pattern is observed for the trends in annual precipitation. Positive trends take place approximately on the two thirds of the basin, where there are two places with maximum values exceeding 10-15 mm/10 years – in the basins of the rivers Khilok and Chikoy and in the town of Babushkin and its adjacent mountainous area. On the other hand, negative trends in precipitation with the gradient of -15 mm/ 10 years are observed in the most part of the Khamar-Daban mountain range, southern Buryatia, the Olkhon area, the coastal area of Barguzinsky Bay, and some other territories.

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Uninodal, binodal, trinodal, and quadrinodal seic_65 map

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Uninodal (bimodal, trinodal and quadrinodal)

seiche oscillations

Seiches are standing waves in an enclosed or partially enclosed water body. Seiche oscillations in Lake Baikal are observed almost continuously throughout the whole year. Some characteristics of these oscillations were obtained from in-situ observations, laboratory experiments on a spatial hydraulic model and from appropriate theoretical calculations. The results of these studies have been published in the works (References). However, available information on Baikal seiches is scarce due to the difficulties of in-situ measurements and rather crude data on bottom topography. Sophisticated instrumental tools and advanced techniques for in-situ measurements were used to perform calculations of seiche oscillations in Lake Baikal based on a spectral difference model using specified bathymetric data obtained by researchers from Limnological Institute SB RAS. All these data are included in this atlas. The main aim of this study was to investigate solutions corresponding to oscillations with the periods of 277, 152, 84, 67, and 59 min, which were identified during in-situ observations.

The spectral difference model is based on the linearized system of equations for shallow water in the spherical coordinate system. Difference approximation is based on irregular triangular spatial mesh. The side length of the calculation mesh is 30 m near the shoreline and about 1 km for the rest of the model area. The numerical model includes solution of the eigenvalues problem. It allows the researchers to get a set of frequencies and corresponding forms of seiche oscillations.

The calculations were obtained taking into consideration the Earth’s rotation. Complex solutions were normalised in such a way that imaginary component was minimal, whereas true components of solutions for the rest of the model area were within the range of -10 to 10. The values in the nodes with the depth less than 10 m and in the nodes within the contour of Maloye More (Small Sea) were not taken into account. Spatial distribution of seiche oscillations with the periods of 276.96; 151.58; 84.25; and 67.38 min corresponds to uninodal, binodal, trinodal, and quadrinodal longitudinal seiche modes of Lake Baikal. The level distribution along the centreline is shown for the enumerated modes in Figure. It should be noted that it is necessary to use other approaches for specification of solutions in shallow areas of Lake Baikal, such as Mukhor and Proval Bays and Cherkalovsky and Posolsk Sors, where the bottom friction is likely to play a significant role. The results for the first mode are consistent with the data on distribution of seiche oscillation height along the Baikal length in [Sudolsky, 1991, Fig. 5.2], in which the data on calculations and survey results from the spatial hydraulic model are compared.

Amplitudes of seiche oscillations in Lake Baikal and their seasonal variability were analysed from the data obtained at 3 stations located in the southern basin of the lake. Well-defined maxima for the oscillations with the periods of 277, 152, 84, and 67 min are observed within the range of density spectrum derived from the annual level record. No significant differences were recorded between the amplitudes for a uninodal seiche and amplitudes during the rest of the year when the lake is covered with ice and protected from wind. It was established that a seiche with the period of 67 min is observed in different seasons of the year. At three stations, level changes for the oscillation with the 277 min period differ in significantly. For the 152 min period they have slight differences, and for the 84 and 67 min periods they are similar only at those sites with relatively high amplitudes of oscillations. This is attributed to the effect of wind and atmospheric pressure. Measured and calculated periods for the first four seiche modes are given in Table.

References

Arsenyeva, N. M., Davydov, L. K., Dubrovina, L. N., & Konkina, N. G. (1963). Seiches in lakes of the USSR. Leningrad: LSU Publishing. p 184.

Verbolov, V. I. (1970). On Baikal seiches. In Seiches in lakes: Surface and internal. Leningrad: Nauka. p 50-52.

Solovyev, V. N. (1925). Method of models and its application in seiche survey at Lake Baikal. News of the Institute of Biology and Geography, 2. p 9-26.

Solovyev, V. N., Shostakovich, V. B. (1926). Seiches in Lake Baikal. Proceedings of Magnetic and Meteorological Observatory, 1.

Sudolsky, A. S. (1991). Dynamic phenomena in water bodies. Leningrad: Hydrometeoizdat. p 263 p.

Sudolsky, A. S. (1968) Laboratory experiments and calculations of Baikal seiches. Proceedings of GGI, 155. p 109-123.

Timofeev, V. Y., Ardyukov, D. G., Granin, N. G., Zhdanov, A. A., Kucher, K. M., Boiko, E. V., & Timofeev, A.V.  (2010). Deformation of ice cover, tidal and true level fluctuations of Lake Baikal. Phys. Mesomech: Special Issue, 13, p 58-71.

Timofeev, V. Y., Granin, N. G., Ardyukov, D. G., Zhdanov, A. A., Kucher, K. M., & Ducarme, B. (2009). Tidal and seiche signals on Baikal Lake level. Bulletin of Inf. MareesTerrestres, 145. p 11635—11658.

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Urbanization map

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Population

The population maps focus on current patterns of the settlement and demographic situation in the Baikal basin. They relate to a complex of underlying social, economic and ecological factors.

The population maps of the Baikal basin are based on the statistical data of the Federal State Statistics Service of the Russian Federation and National Statistical Office of Mongolia. Also important were the data from population censuses of Russia and Mongolia and the data of the current measurements of demographic events. The authors used statistical sources to calculate indicators for territories included into the Baikal basin.

The distribution of settlements within the Baikal basin is quite irregular. There are four locations of the regional concentration of the population. In Irkutsk oblast, the main settlement belt along the Trans-Siberian Railway stretches from the western border of the region up to Lake Baikal. Here, there are many agricultural settlements and the majority of large administrative and economic centers, where manufacturing sector dominates the economy. Irkutsk – a large multi-functional center – tops the group of these settlements. Only sparsely populated the Olkhon and Slyudyanka districts and part of the Irkutsk district fully lie within the Baikal basin. In the direct vicinity of Lake Baikal, but in the Angara basin, there are cities of Irkutsk and Shelekhov. In the Republic of Buryatia, there is a major settlement area around Ulan-Ude with a maximum concentration to the south of the city. Geographic differences in the specialization of settlements have emerged. Settlements involved in manufacturing and transportation are overwhelmingly dominant along the Trans-Siberian Railway. In Southern Buryatia, there are mostly agricultural settlements. In Zabaikalsky krai, there are three settlement networks: settlements involved in manufacturing and transportation located along the railway; mining settlements near deposits; and agricultural settlements located south of Chita in the forest-steppe and steppe zone. In Mongolia, the population is mainly concentrated in the central region – from Ulaanbaatar in the south to Sukhbaatar in the north. Three largest cities of the country and more than a half of its population are located in this area. The other territories of the Mongolian part of the Baikal basin are sparsely populated.

Distribution of the population and the degree of the settlement of the territory are displayed on the maps “Density of population (as of 1.1.2013)”; “Density of rural population and population size of urban settlements (as of 1.1.1989)”; “Density of rural population and population size of urban settlements (as of 1.1.2013)”.

The Baikal region belongs to sparsely and unevenly populated territories. The population density of the Baikal basin is 17 times lower than the world’s average of 53 persons/km2. The population density in the Russian part of the basin is 2.9 persons/km2, which is nine times lower than in the European part of Russia (26 persons/km2).

The intra-regional differentiation of settlement patterns is stipulated by several spatial gradients of the population density decrease, with the main gradient leading from the center (capitals and administrative centers) to the periphery. Other gradients are also present in particular territories. Thus, in the Russian part of the basin, the population density tends to decrease as it goes from the south to the north and from the west to the east. The Russian-Mongolian border for the most part rather separates than unites the areas of settlement, except for one direction. The core of this direction is the Selenga Valley, where an area with a highly dense population has formed between Ulaanbaatar and Ulan-Ude.

The territories around large cities, like the regional centers Irkutsk, Ulan-Ude and Chita, are most densely populated. Along with the areas with dense population, there are also virtually unpopulated territories of tens of thousands square kilometers in area. The distribution of rural population is less contrasting than the urban one. The main clusters of rural population are located in the forest-steppe and steppe zones, where the density of population may reach 10-20 persons/km2. Rural population is mainly concentrated in the south of Irkutsk oblast (around Irkutsk) and in the central part of Buryatia (south of Ulan-Ude).

The major cities of the Russian part of the basin grew along the transportation lines. Thus, 11 out of 13 towns are located along the railways. Only Zakamensk and Kyakhta are located away from the railroad. In the Mongolian part of the basin, the connection of urban settlements to transportation lines is less pronounced with only five out of 12 towns being situated on the railways.

The map “Dynamics of the population size (1989-2013)” shows considerable changes in the population size – a situation, where a high concentration of the population in a few largest centers is followed by depopulation of vast territories.

In the Russian part of the basin, there were two clear patterns of the population size dynamics from 1989 to 2013. Firstly, the decrease of population tends to be more pronounced from the southwest to the northeast. Secondly, the population dynamics in regional centers (Irkutsk, Ulan-Ude, and Chita) and their suburbs is relatively positive. Population growth is observed only in the Irkutsk, Shelekhov, and Olkhon districts of Irkutsk oblast, Ivolga district of the Republic of Buryatia and Chita district of Zabaikalsky krai. The record level growth of population (over 160 %) was recorded in the suburban Ivolginsky and Irkutsk districts. The biggest drop in the population takes place in the localities that are classified as districts of the Far North, with the Muisky and Severobaikalsky districts of the Republic of Buryatia loosing over half of their population.

In the Mongolian part of the Baikal basin, population growth is registered on over a half of the nation’s territory. The main Mongolian cities – Ulaanbaatar, the capital of Mongolia, (244 % to the level of 1989), Erdenet, and Darkhan are the fastest growing cities. The Khovsgol and Selenga aimags also demonstrate a significant growth of population. The population in the four aimags of Arkhangai, Zavkhan, Tov, and Khentei decreases due to an outward migration of residents.

The contrasting nature of the population dynamics within the Baikal basin is quite distinct:

– The Russian part of the Baikal basin is characterized by the type of the population dynamics, where an outward migration is several times higher than a natural population decline;

–        The Mongolian part is characterized by the type of the population dynamics, where a natural increase of population prevails over inward migration.

Territorial specifics of demographic development are shown on the map “Natural increase of population”.

In the Baikal basin, different modes of reproduction of population exist along with a wide variety of quantitative parameters of demographic processes. In general, it is possible to identify two types of population reproduction. Thus, all of Mongolia, Tuva and part of Buryatia are characterized by an expanded type of reproduction with high birth rates, average mortality, and a significant natural growth. The Baikal region of Irkutsk oblast, Zabaikalsky krai, and most of Buryatia is characterized by a narrow type of reproduction with low birth rates, high mortality, and a natural population decline or insignificant natural growth. The annual natural growth of the population in Mongolian aimags is 17-19%. In the Russian part of the basin, natural movement of the population led to mixed results, where 23 municipalities showed population increase, while 10 municipalities had natural decline. With an average natural population increase of 1.4 per mille, there were significant variations – from the decline ranging from -5 to -6% (in the Petrovsk-Zabaikalsky, Irkutsk and Olkhon districts) to the increase exceeding 10 pro mille (10.4% in the Dzhida district, 12.1% in the Kizhinga District, and 16.0% in the Tere-Khol district). The natural population increase in the Mongolian capital Ulaanbaatar was 17.2%, while the increase in the Russian regional centers Ulan-Ude and Chita was 4.3% and 3.4%, respectively, with the decline of -2.7 % in Irkutsk.

The map “Urbanization of the territory” shows the proportion of urban population in Russian municipal districts and Mongolian aimags. The share of urban population exceeds 74% of the entire population and is composed of a few territories. The level of the urbanization of the population exceeds the world’s average (51%) by nearly one and half times, however, the level of the urbanization of the territory is low. Urban territories mainly include settlements located along the railways, as well as densely populated administrative centers. In the Mongolian part of the Baikal basin, only Ulaanbaatar and the Orkhon and Darkhan-uul aimags are highly urbanized, while the remaining nine aimags have only a small share of urban population (17.5%-34.9 %). In Mongolia, administrative centers of every aimag must be urban settlements. However, in Russia, the legislation does not mandate municipalities to have urban settlements. Therefore, in the Russian part of the basin, as of 2013, 14 districts did not have urban population at all. Some settlements (Barguzin, Ivolginsk, Kyren, and Khorinsk) rejected their urban status in the process of municipal reforms of the 2000s. The population of Mongolian towns within the basin nearly doubled in 1989-2013, with the population of Ulaanbaatar growing from 540.6 to 1,318.1 thousand people. The population of the largest cities in the Russian part of the basin did not change that much: in Irkutsk, it grew from 572.4 to 606.1 thousand people, in Ulan-Ude – from 352.5 to 416.1, while in Chita it declined from 365.8 to 331.3 thousand people.

The main results of migration processes in 2010-2012 are shown on the map “Migratory increase of population”.

In Russia, including the Baikal basin, the last two decades witnessed a significant decrease of migration activity of the population. However, outward migration from the region remains high and reproduces almost annually from the mid-1990s up to now. Population movement has mostly become intra-regional – the intra-regional migration turnover makes about 2/3 of relocations in the Baikal basin. The intra-Russian interregional migration causes migration losses, while migratory relationships with the CIS countries contribute to a considerable growth of population.

Redistribution of the population between the constituent parts of the Baikal region is intensive including some tens of thousands people annually. In 2010-2012, on average 66.5 thousand people arrived, and 58.6 thousand left. In the Baikal region, the average annual migration increment was 7.9 thousand people. However, it was due to the growth in the attractive for migrants cities of Irkutsk and the Irkutsk district (+9.3 thousand people), Ulan-Ude (+3.4 thousand people) and Chita (+2.9 thousand people). The total growth of the population in these cities was 15.6 thousand people. The rest of the region experienced the outflow of residents totaling 7.7 thousand people. Migration redistribution leads to the growth of the population in regional centers and their suburbs. Only 10 municipalities had a migratory growth, while the rest 24 showed a decline. The intensity of migrant arrivals is highest (twice as high as average) in the suburban Irkutsk and Ivolginsky districts, while the intensity of departures is highest (twice as high as average) in the undeveloped Dzhida, Kizhinga and Muisky districts. Against this backdrop, the Russian part of the Baikal basin has two migration poles – the Irkutsk and Dzhida districts, where an average annual migration balance is +47.4% and -46.0%, accordingly.

In general, the majority of territories is characterized by a progressive outward migration, which is compounded by unfavorable structural features of the outflow (with young and educated groups of people leaving the region). The results of migration movement are clearly expressed in terms of the center-periphery relationship: there are three areas of migration growth in the Russian part of the basin (Irkutsk, Ulan-Ude, and Chita with their suburban districts) and one in the Mongolian part, which combines the capital Ulaanbaatar and the aimags lying to the north of it –  Selenge, Orkhon, and Darkhan.

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