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Average annual rainfall in mm map

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Mean annual precipitation

Particular features of the mountainous topography have a significant impact on the formation and distribution of precipitation over the study area. The altitude and especially the location of mountains with respect to moisture-laden air flows lead to uneven distribution of precipitation. Different precipitation amount is observed at the same altitudes of mountain ranges. The greatest precipitation amount characterizes the north-western and western slopes of primary (with regard to prevailing air flows) ridges bordering Lake Baikal, i.e. up to 1400 mm; on the windward slopes of secondary ridges and within the plateau inner areas it reaches up to 400-700 mm. Precipitation amount of 200-250 mm fall out in the steppe part of the western shore of Lake Baikal and on its islands, and up to 300 mm precipitate in the intermontane depressions and in the Selenga and Uda river valleys.

Annual precipitation amount of 250-300 mm falls out in the mountains of Khentei at altitudes above 1000 m, in the mountains of the Khovsgol area at altitudes above 1500 m, and in the mountains of Khangai at altitudes above 2000 m. Summer precipitation predominate, constituting 60-70% of the annual amount.

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Averagelong-termrunoff map

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Flow

The map “Mean annual flow” reflects the formation patterns of the water regime of the territory, which are determined by the properties of landscapes to transform atmospheric moisture into the runoff.

For a water body basin, the surface runoff is the total amount of water loss from the watershed landscapes. The runoff rate from landscape complexes is determined by solving the inverse problem, i.e. identification of the connection of flow rate at the main stream station of a catchment with the runoff from landscapes, occupying its area, and is calculated based on the equation Qj = ∑qi fij, where j is the index of the river basin, Qj is its runoff, L/s; qi is a modification of flow from the i-th landscape complex, L/s km2; fij is an area of the j-th basin occupied by the i-th landscape, km2. Long-term average runoff data for small and medium-sized rivers of theLake Baikal basin were used in calculations for the map construction [Long-term…, 1986, http://www.r-arcticnet.sr.unh.edu]. Characteristics of landscape components were obtained on the basis of the materials on landscape of the Baikal region [Landscapes…, 1977, Natural..., 2009, Landscapes…, 1990, Lysanova et al., 2009]. In accordance with the regional dimension, generalization degree is chosen at the geom level, and their average annual flow moduli are determined. The territory on the map is divided into regions according to five gradations of the module - from less than 1 to more than 10 L/s km2.

The catchment area of the lake covers a variety of landscape zones and altitudinal belts, which makes a great contrast between the runoff rates. The highest annual flow moduli are formed within the goletz and mountain-taiga landscapes. Steppe and forest-steppe areas are distinguished by the minimum runoff rates, and in the desert regions of Mongolia (the Selenga river basin) flow formation almost does not take place.

The maps of minimum and maximum flow were compiled based on the typological landscape classification represented on the map [Landscapes…, 1977]. In the course of investigation, landscapes of different types were generalized by identifying the most hydrologically informative properties (morphological characteristics, vegetation structure, altitudinal zonation, etc.). As a result, more than 200 landscapes were combined into sixteen types of natural complexes, and runoff rates were determined for them. The moduli of maximum snow runoff and minimum summer runoff were calculated as described above.

Areas with the highest runoff of floods are confined to the mountain ranges and systems with goletz open woodlands and mountain-taiga landscapes. The main areas, distinguished by formation of frequent and high floods are the Baikalsky Range on the north-eastern end of the lake; Barguzinsky Range, located in the south-eastern part of the catchment, and the Khamar-Daban, covering the south-western shore of Lake Baikal. The values of the maximum flow modification are shown in three gradations on the map, namely: less than 25, 25-70, and more than 100 L/s km2.

Features of formation of the minimum summer runoff in the Baikal basin are associated with the regime of atmospheric moisture, as well as with the effects of altitude and exposition. The calculations and analysis of the minimum summer runoff have shown a relatively high water yield in the low-flow period from high-mountain taiga landscapes and extremely low river flow formation in the central areas of the Selenga river catchment and in Priolkhonie, which are covered with light coniferous landscapes and steppe complexes on slopes and plains. The map shows the value of the minimum flow in three gradations, namely: less than 1.5, 3.0-5.0, and more than 5.0 L/s km2.

Landscape-hydrological mapping based on the quantitative characteristics of water yield of landscape complexes objectively reflects the hydrological organization of the territory.

References

Kuznetsova T.I. (2009). Map "Natural landscapes of the Baikal region and their use: purpose, structure, and content”.  T.I. Kuznetsova, A.R. Batuev, and A.V. Bardash. Geodeziya i kartografiya, , no 9, pp. 18-28.

Landscapes of southern East Siberia [Maps]: [physical map] (1977) / compiled and prep. for printing by factory no. 4 GUGK in 1976, authors: V.S. Mikheev and V.A. Ryashin. 1: 1 500 000, Moscow: GUGK, 1 map (4 sheets): col.

Landscapes [Maps] [physical map] / The National Atlas of the Mongolian People's Republic. / comp .and prep to print by GUGK in 1989, authors: B.M. Ishmuratov, K.N. Misevich, I.L. Savelyeva, et al.

Lysanova, G.I., Semenov, Yu.M., Shekhovtsov, A.I., and Sorokovoy, A.A. (2013). Geosystems of the Republic of Tuva. Geografiya i prirodnye resursy, no. 3, pp. 181-185.

Long-term data on the regime and surface water resources. The Baikal basin. (1986). Vol. 1, no. 14, Leningrad: Gidrometeoizdat, 361 p.

A Regional, Electronic, Hydrographic Data Network For the Arctic Region. URL: http://www.r-arcticnet.sr.unh.edu

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Bottom contour map

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Bottom relief

The history of depth measurements in Lake Baikal goes back to 1798, when E. Kopylov and S. Smetanin, employees of a mine plant, carried out 28 measurements between the head of the Angara river and the mouth of the Selenga river. One of such measurements yielded a maximum depth of 1,238 m. Lake Baikal was immediately recognised as the second deepest lake in the world.

In the period of 1869-1876, B. Dybovsky and V. Godlevsky compiled a detailed and precise (for that time) map of Southern Baikal, which covered 11 cross-sections. Measurements of depth were carried out from the ice, which provided high accuracy [Dybovsky, Godlevsky, 1871, 1877].

In 1902 and 1908, the Pilot Chart of Lake Baikal and Atlas of Lake Baikal were published as a result of numerous hydrographic expeditions under the leadership of F. Drizhenko, in which the depths were shown in detail for the coastal areas of the lake.

In 1925, the USSR Academy of Sciences developed a long-term project under the supervision of G. Vereshchagin to study bathymetry of Lake Baikal. This initiative resulted in the organisation of Limnological Station, later reorganised into Limnological Institute. This project helped discover the deepest place in the lake and an underwater shallow ridge named the Akademichesky Ridge, which separates the northern basin from the central one. New bathymetric maps (scales 1:300,000 and 1:500,000) were compiled. They were demonstrated at the International Limnological Congress held in Rome in 1934.

In 1962, A. Rogozin and B. Lut compiled a new bathymetric map (scale 1:300,000) as a result of long-term bathymetric expeditions. Based on this map, the Central Department for Navigation and Oceanography of the Ministry of Defence of the USSR (CDNO) published maps  “Northern and Southern Areas of Lake Baikal”  in 1973 and 1974.

In the period of 1979-1985, CDNO carried out new systematic echo-sounding bathymetric measurements throughout the entire Lake Baikal. Traverses had a spacing of 100 and 250 m in the coastal waters and 1 km in the abyssal areas. As a result of these investigations, a four-sheet bathymetric map of Lake Baikal was published in 1992 (scale of 1:200,000). To date, this is the most reliable bathymetric map of Lake Baikal. However, it has some shortcomings:

  • Bathymetry is based only on some available original data;
  • Bathymetry is presented by the contours of isobaths that were taken manually;
  • Bathymetry is mainly represented by isobaths with a step of 100 m up to a depth of 1,000 m and 500 m for depths exceeding 1,000 m;
  • Recent investigations showed that significant discrepancies can exist between true depth values and echo-sounding measurements, which are attributed to discrepancies between the real acoustic speed in Lake Baikal and the calculated rate for the echo-sounder.

In 1999, an international group of experts was organised to jointly compile a new, more precise bathymetric map of Lake Baikal. It was necessary to carry out more detailed recalculations of measurement values, which were used for maps in 1992, to digitise and adjust them to the real acoustic speed, to integrate them with the echo-sounding data obtained earlier, and to compile a new more complete computer map of Lake Baikal based on all available measurement data. This project was financially supported by INTAS (International Association for the Promotion of Cooperation with Scientists from the New Independent States of the Former Soviet Union).

The CD ROM is available with final results of this project. Coordinates of points are in a Mercator’s projection, WGS 1984 ellipsoid. The latitude for all generated maps is 53o 0’ 00’’ N.

New bathymetric data made it possible to obtain specified morphometric information on Lake Baikal and to present it in tables. Taking into account that the lake surface is at 455.5 m a.s.l. (Baltic System of Heights), the deepest point of Lake Baikal is situated at 1186.5 m below the sea level.

The relief of the bottom of Lake Baikal is represented by isobaths with a step of 100 m. The lake consists of three basins: Northern basin – the most shallow one with a maximum depth of 904 m and an average depth of 598.4 m. Central basin is the deepest one. Its maximum depth is 1637 m, while the average depth is 856.7 m. Southern basin’s maximum depth is 1461 m with the average depth of 853.4 m. The existing Baikal depression is asymmetric: its northern and northwestern slopes are very steep, while the southern and southwestern slopes are more flat. Maximum depths are located at a distance of one third of the lake’s width from the steep northwestern slope. There is a shallow platform – a shelf - on the lake's northern and northwestern side, which is weakly developed. The shelf on the southern and southwestern coast is more pronounced.

Measurement results demonstrated that in the place of the supposed maximum depth of 1741 m, according to G. Y. Vereschagin, the actual depth is less than 1600 m - 1593-1596 m. Based on the data derived from echo sounding, the deepest part of Central Baikal is located between Cape Izhimei and Otto-Khushun. In 1972, control measurements using the NEL-5 echo-sounder showed the depth of 1637 m [Lut, 1987].

Numerous underwater works using Pisces, Mir-1, and Mir-2 submersibles offered an opportunity to visually examine morphologic and morphometric features of the underwater slopes and compare these data with the results of echo sounding. Northern and northwestern slope is sporadically covered with silt deposits with bed rock monoliths protruding between silty patches.

The steepest part of the underwater slope is located on the northern side of the depression near Cape Kolokolny, about 40 km from the southern edge of the depression. The total steepness of the slope here reaches 60-65 degrees, however, its steepness is lower than the steepness on the Baikal side of Olkhon Island by 10-15 degrees [Lut, 1987]. The steepness of northern and northwestern slopes reaches 60-40 degrees. According to the Pisces XI expedition on September 22, 1991, negative slopes at the depth of more than 700 m were observed. The steepness of the southern and southeastern slope is five to six times lower.  The average slope of the whole lake is four degrees.                                                                                                                                                                                                                                                                                                                                                     

References

Drizhenko, F. K. (1902). Pilot Chart of Lake Baikal.

Drizhenko, F. K. (1908). Atlas of Lake Baikal.

Dybovsky, B., Godlevsky, V. (1871). Report on depth measurements in Lake Baikal carried out in spring of 1871. Bulletin of the East Siberian Department of the Imperial Russian Geographical Society, 2(5). p 6-16.

Dybovsky, B., Godlevsky, V. (1877). Report on experiments in 1876 (Profiles of Lake Baikal in the appendix Bulletin of the East Siberian Department of the Imperial Russian Geographical Society, 8. p 115-135.

Lut, V. F. (1987). Morphology and morphometry of the Baikal basin. The way of knowing Baikal. Novosibirsk: Nauka. p 34-47.

Northern Area of Lake Baikal. Scale 1:300,000. (1973). Leningrad: GUNIO.

Southern Area of Lake Baikal. Scale 1:300,000. (1974). Leningrad: GUNIO.

Lake Baikal (4 sheets). Scale 1:200,000. (1991, 1992). Leningrad-St. P: GUNIO.

De Batist, M., Canals, M., Sherstyankin, P. P., Alekseev, S. P., and Teams (2002). The INTAS Project 99-1669, October 2002.

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