Features of the weather in Siberia. Climate of Eastern Siberia

Eastern Siberia is characterized by pronounced continental climate features. This is manifested in exceptionally large seasonal differences in air temperature, low temperatures, and little precipitation in the area. In winter, it is formed under the influence of a vast area of ​​elevated - Asian. However, the position of the center of the anticyclone, the pressure in it and the area of ​​distribution change significantly during the cold period. This determines the variability, which is associated with day-to-day fluctuations in air temperature, which is especially typical for the southwest of Yakutia.
Although cyclonic activity is weakened in winter, it significantly affects the weather: it changes, precipitation occurs, and it forms.
Continental air predominates here, which cools in the surface layer, and in December - February in the lower layers it becomes colder than the Arctic air. The average in January over the vast expanse of Eastern Siberia varies from -26 in the southwest to -38, -42° in the Central Lowland. In valleys and basins it can drop to -60°.
However, against the background of very low average monthly temperatures, when warmer continental air is carried out from Central Asia, relative warming is observed in the Baikal region and Transbaikalia, accompanied by an increase in temperature to -15° and above. During prolonged exposure to relatively warm air masses Daytime air temperatures in Eastern Siberia can be above 0°.

Summer in Eastern Siberia is warm: up to 30 - 40% of solar heat is consumed to heat the air, and in the south and east of the Central Yakut Lowland up to 50%. Therefore, despite the flow of cold air from the seas, from the north and from the sea, average temperatures in July vary across the territory from north to south from 14 to 18°. The most high temperatures in these areas they occur when continental air is carried out from China and (35 - 38°).
In summer, the frequency of occurrence over Eastern Siberia is greater than in winter. They mainly come from the west, southwest and northwest. In the second half of summer, southern cyclones occur, which are associated with significant precipitation.
Relief and features distribute precipitation throughout the area. The annual amount of precipitation varies between 130 - 1000 mm, and there is no well-defined, as in the European territory of Russia and Western Siberia, gradual decrease in precipitation to the south. The combination of heat and moisture promotes forest growth across most of Eastern Siberia. However, the complex terrain of this region disrupts the natural environment.
Most favorable conditions(enough heat and moisture) are formed in areas where precipitation falls from 600 to 1000 mm. To the east, in the territory of Central Yakutia, with a decrease in precipitation to 200 - 250 mm, aridity increases. Only here, at latitudes around 60 degrees, negative differences between precipitation and evaporation are observed, which forms steppe zones. The climate of its coasts is maritime in nature, which is determined by the large size of the lake and its isolation from the surrounding area by mountain ranges. In winter, a center of low pressure forms over Lake Baikal. And from the area of ​​​​high pressure over Eastern Siberia they blow towards Lake Baikal. The minimum precipitation is observed in February - March (10 - 20 mm). In Transbaikalia, due to a decrease in precipitation to 300 - 400 mm, aridity increases from north to south. In the southwest and especially in the southeast of Transbaikalia, where evaporation exceeds precipitation by 200 mm, they form. However, greater aridity is observed in river valleys, in intermountain basins and on the southern slopes. Unlike other regions of Russia, in Eastern Siberia on the northern slopes it extends into the southernmost regions of Transbaikalia, and steppes along river valleys are found north of 60° N. w.

Central Siberia

Siberia has been and remains a unique part of planet Earth. The unique scale of its territory, the diversity of natural and climatic conditions, flora and fauna found in the depths of mineral resources, the energy capacity of rivers and the purity of lake waters, the original history and culture of the peoples inhabiting it. It is no coincidence that Siberia was originally called a land or a country. The annexation of Siberia became the most valuable acquisition of the Russian state during its entire existence and the most important milestone in the formation of the Russian Empire.

The first information about the nature of Central Siberia - its rivers, climate characteristics and fur riches - was obtained as a result of the campaigns of Russian “service people” at the beginning of the 17th century. Their observations were used to compile maps and drawings that contained a fairly accurate image of the most important geographical objects of the country for that time. In the 19th century, reconnaissance missions were carried out Scientific research many regions of Central Siberia. At the beginning of the 20th century, mineral deposits of Central Siberia (gold, coal, iron ores), navigation conditions on rivers and climate were studied. Expeditions of the Resettlement Administration undertook large-scale research of soils and vegetation in the southern regions of the country.

Currently, the nature and natural resources of Central Siberia have been studied relatively well. Deposits of various minerals have been discovered in the depths of the region. Hydropower resources and conditions for the construction of powerful hydroelectric power stations on the Angara, Lena and other rivers were studied.

Central Siberia has its own distinctive features of flora and fauna and its own contribution to the overall structure of life on Earth.

Nature of the Central Siberian Plateau

Geographical location, geological structure, tectonics and history of development of the territory

The Central Siberian Plateau is located between the Yenisei and Lena rivers. In the north, the plateau drops steeply to the North Siberian Lowland, and in the south it approaches the foothills of the Eastern Sayan Mountains, the Baikal region and the North Baikal highlands. The average heights of the plateau reach 500 – 700 meters. The most elevated areas are 1500 – 1700 meters (Putorana Plateau).

The most ancient section of the plateau is the Siberian Platform. The most important feature The structure is the high position of the Argian and Lower Proterozoic folded foundation and the overlying sedimentary Upper Proterozoic and Paleozoic deposits, penetrated by volcanic rocks and exposed to the ancient surface in most of the territory. Anteclises and syneclises were created by oscillatory movements on the platform; the depth of the foundation in the latter reaches 5000 - 7000 meters.

The Siberian platform has two large uplifts of the Argian basement - the Anabar and Aldan shields. The Anabar Shield is located in the upper part of the Anabar River basin. The folded base is most elevated in the central part and comes to the surface, and at the edges the surface of the foundation sinks under sedimentary deposits.

In the west of the Siberian Platform, dislocated Riphean rocks emerge (crystalline schists, tess, marbles, quartzites, all of them are intruded by intrusions), forming protrusions of the Baikal platform foundation - the Yenisei and Turukhansk uplifts.

The sunken sections of the foundation form syneclises and troughs. In the basins of the Angara, Kureika, Nizhnyaya and Podkamennaya Tunguska rivers there is the Tunguska syneclise, which is filled with Cambrian sediments and marine lagoonal sediments of the Devonian and Lower Carboniferous. Upper Paleozoic and Early Mesozoic rocks fill the entire Tunguska syneclise and consist of the so-called Tunguska suite, which is formed by thick continental sediments (sands, sandstones, gray clays and coal layers), tuffaceous suite and traps. Coal-bearing strata belong to the Carboniferous and Permian systems, forming the Tunguska basin. Its area is 1 million km2.

Eruptions and intrusions of basic rocks (diabases and basalts) began in the Permian period and continued until the beginning of the Jurassic. Volcanic processes on the Central Siberian Plateau manifested themselves in the form of powerful effusions that formed colossal lava covers, sheet intrusions and laccoliths in the thickness of the Upper Paleozoic rocks. The main distribution of traps is associated with the Tunguska syneclise, but they are also found beyond its borders. Under the influence of trap intrusions, some of the coals turned into graphite High Quality. The largest graphite deposits are concentrated in the lower parts of the Kureika and Nizhnyaya Tunguska river basins.

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The Vilyui syneclise is located between the Anabar and Aldan shields. At its base is the Ura aulacogen, filled with Proterozoic rocks. In place of the aulacogen, the Vilyui syneclise developed with a thick layer of Paleozoic and Mesozoic sediments, among which there are deposits of Cambrian salt, Jurassic and Cretaceous coals.

In the Carboniferous and Permian, the northwestern part of the platform subsided - the Tunguska syneclise was formed. Its surface was covered with lakes and swamps, and coal accumulated.

During the Jurassic period, due to tectonic activity, the formation of the main morphostructures occurs; in zones of stable subsidence, negative morphostructures emerged (Vilyui syneclise, Angara-Vilyui and Prisayan troughs), and in zones of uplift - positive ones (straight lines - Anabar anteclise; reverse ones arose in the Tunguska syneclise, Putorana plateau, etc.).

From the end of the Paleogene to the beginning of the Pleistocene, due to neotectonic movements, further changes in the relief and the formation of modern morphostructures occur.

By the beginning of the development of the continental branch, the Central Siberian Plateau rose again, due to which the rivers cut in and lower basement and accumulative terraces formed in their valleys. In the valleys of large rivers there are up to 8-10 terraces. Simultaneously with the incision of the rivers, the ledges of the Byrranga and Putorana plateaus were formed, facing the North Siberian Plain, which sagged and was filled with the waters of the Borgal transgression. Marine Quaternary deposits of this transgression are now located at altitudes of 200-220 meters.

In the Pleistocene, under the influence of glacial gouging and accumulation, erosion, nivation, frost weathering, solifluction and permafrost, morphosculpture is formed. The northwestern part was covered by Middle Pleistocene and Late Pleistocene glaciations, the centers of which were located in the Byrranga, Putorana and Anabar shield mountains. To the south of the glaciation boundaries, severe perigmatic conditions existed.

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In general, Central Siberia is confined to the Central Siberian Plateau, a country of traps and Tunguska coals. It has a fire-breathing past, although now there are no active or extinct volcanoes here. At first Mesozoic era the nature was different: interstratal and vein penetrations of magmatic masses penetrated the body of the platform and the structures of adjacent troughs, and in some places lavas flowed onto the surface. A complex system of frozen volumes of magma survived in the depths; erosion revealed them in the form of armor layers on vast plateaus with an area of ​​up to a million km2. Where strata intrusions were located in several tiers, stepped slopes arose (these lava layers are called traps - from Swedish “stairs”). The vents of many Mesozoic volcanoes are explosion tubes; during their formation, rare conditions arose that were necessary for the birth of diamond crystals. Two outcrops of the deep foundation of the Siberian Platform - the Anabar Shield and the Yenisei Ridge - were built by Precambrian rocks, and the Anabar structures are older than the Yenisei ones. In other areas, the platform is two-tiered - the foundation is covered by horizontally lying sedimentary strata of Paleozoic age, the extensive basement trough is the Tunguska depression. Here, in the thick thickness of continental strata, the coal-bearing Tunguska formation was concentrated in the Upper Paleozoic and early Mesozoic. This is how one of the richest coal basins in the country, the Tunguska, arose.

In the south the platform is bordered by the Pre-Sayan trough, in the north there is the North Siberian depression. Only in the east is the border devoid of certainty - the structures of the platform gradually sink towards the Vilyui depression, and the relief of the plateau just as imperceptibly turns into a plain.

Millions of years of erosion would have long ago turned the territory into a residual plain, but the newest uplifts, cracking, humping and tilting the surfaces, revived the incision of the valleys, and karst was powerfully formed in the salt-bearing and limestone strata over vast areas - caves and tunnels with underground rivers arose.

The geographical position of the Central Siberian Plateau on the ancient Siberian Platform determined the complexity and diversity of the geological structure, the development of physical and geographical processes, the nature of minerals and the formation of natural complexes. The territory of the region is composed of rocks of Precambrian (Archaean, Proterozoic), Paleozoic, Mesozoic and Cenozoic age, that is, ranging from ancient to modern formations.

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Relief

Compared to the rest of the predominantly mountainous High Siberia, Middle Siberia seems relatively flat, like an intermediate step between the plain of the west and the mountains of the south and east. But its surface can hardly be called a plain. More than a quarter of the territory is characterized by complex mountainous terrain. The word “plateau” itself is more of a tribute to tradition. Geographers' acquaintance with this country began with its flat parts, and horizontally lying strata were visible in the cliffs of the outskirts.

Along the meridian, Central Siberia is elongated, like Western Siberia, but the differences between the latitudinal zones recede into the background here. Almost the entire plateau is dominated by a variety of landscapes, this is facilitated by differences in the structure of the subsoil, the recent uplift of the protrusions of the ancient foundation and the high mobility of the younger margins of the plateau. Its northern and middle parts are more stable - the platform is stable here, while the south lies beyond it - these are ancient foothill troughs. The strata in them are disturbed by long-standing processes of folding, and the latest erosion creates not only table and stepped plateaus, but also beveled ridges, and in the Cis-Baikal trough even ridges.

The Central Siberian Plateau formed in the western part of the Siberian Platform, the structures of which were rigidly welded together as a result of trap magmatism. This entire territory in the Meso-Cenozoic steadily rose as a single structure and is represented in relief by the largest orographic unit. The Central Siberian Plateau is characterized by significant elevation and contrast of relief. The altitude within its boundaries ranges from 150-200 to 1500-1700 meters. The average height is 500-700 meters. A distinctive feature of the plateau is the combination of a predominantly flat or gently undulating stepped relief of the interfluves with deeply incised steep-slope (often canyon-like) river valleys.

In terms of the nature of the distribution of heights and dissection, the Central Siberian Plateau is very heterogeneous. Within its boundaries, more fractional orographic units are distinguished. The plateau reaches its maximum heights in the north-west, where the Putorana plateau (up to 1701 meters) and Syverma (more than 1000 meters) rise. They are adjacent to the Anabar Plateau, the Vilyui and Tunguska plateaus with altitudes of up to 850-950 meters.

From the Central Yakut Plain, located east of the Central Siberian Plateau, and confined to the Vilyui syneclise and the Predverzhoyansky trough, a lowland strip (300-500 meters) stretches through the territory of the plateau to the foot of the Sayan Mountains. Within its borders are the Angara and Central Tunguska plateaus. To the southeast of this strip the surface rises. Here are the Angara Ridge and the Leno-Angarsk Plateau with an altitude of up to 1000-1100 meters. To the northeast they pass into the Lena Plateau, limiting the Central Yakut Plain from the south. Thus, according to the altitude position, the Central Siberian Plateau is clearly divided into three parts: the northwestern - the most elevated, the central - lower, the southeastern - elevated.

The Central Siberian Plateau is characterized by the development of a multi-tiered stepped relief, the formation of which is due to the structural features of the Siberian Platform, long-term continental denudation since pre-Jurassic times, the lithology of the constituent rocks - dense traps and less stable sedimentary rocks of Pamozoic and Mesozoic age and recent tectonic movements that intensified the denudation process. Watershed spaces take the form of either isolated mesas or elongated ridge-like hills. In some places, under uniformly leveled surfaces, individual ridges composed of volcanic rocks (diabase and basalt) rise. The flat areas are swampy in some places. In the northwest is the Putorana plateau, composed of traps and volcanic tuffs. In its middle part, in the upper reaches of the Katanga River, the maximum heights are concentrated (1701 meters). To the west and east, the height of the mountains gradually decreases to 600-700 meters. Traces of ancient glaciations are widespread in the mountains. The bottom of the intermountain depressions is occupied by rivers (the upper reaches of the Pyasina, Kheta and others) and lakes (Keta, Khantaiskoe). In the upper reaches of the Anabar and Olenek rivers there is the Anabar Plateau with glacial processing. Its maximum heights reach 700-900 meters. From the southwest, the Central Siberian Plateau borders the Yenisei Ridge; it extends from the mouth of the Podkamennaya Tunguska River almost to the Eastern Sayan, which is separated by a tectonic depression. The highest height of the Yenisei Ridge is Mount Epashimsky Polkan (1104 meters).

Thus, the relief of the Central Siberian region was formed under the influence of internal and external forces manifested on our planet. Of course, he is quite unique.

At the base of the Central Siberian Plateau lies a rigid array of ancient crystalline rocks that are weakly compressible, which determined the nature of the relief of the plateau. From above these rocks are covered with traps.

Climate of Central Siberia

The climate of the territory is sharply continental. Continental climate is determined geographical location and relief. The territory is located in the center of the northern part of Asia, elevated, remote from warm seas, fenced off from them by mountain barriers. In most of the territory, except for the south, the radiation balance is negative meaning from October to March. The formation of climate is significantly influenced by orographic conditions. Large mountain ranges and deeply incised river valleys determine local climatic differences, uneven distribution of precipitation during winter temperature inversions. In terms of the annual number of hours of sunshine, the southern part exceeds many southern regions of the country: in Irkutsk it reaches 2099 hours. Compared with the climate of other territories located at the same latitudes, the continental climate is expressed in the coldest and coldest winters, the warmest summers and the least annual precipitation. Therefore, the climate is characterized by a large temperature amplitude and negative annual temperature air (Bratsk –2.60С).

Precipitation falls mainly in summer, 4-5 times more than in winter, which is twice as long as summer. On the Central Siberian Plateau, the annual precipitation is 300-400 millimeters. The continental climate increases towards the east, which is expressed in a decrease in precipitation, and in the mountains the amount of precipitation increases.

In winter, the entire territory is greatly cooled, which contributes to the development of a stable powerful anticyclone from October to March. From the center of the Asian anticyclone, a spur of high pressure actually extends to the north and northeast, filling almost the entire territory. Cold continental arctic and temperate air masses dominate. The weather is mostly clear, windless, with low temperatures.

In winter, precipitation is occasionally brought by cyclones coming from the west. The long stay of slow-moving anticyclones over the territory causes a strong cooling of the surface and ground layer of air, and the occurrence of powerful temperature inversions. This is also facilitated by the nature of the relief: the presence of deep river valleys and basins in which masses of cold, heavy air stagnate. The prevailing continental air here temperate latitudes characterized by very low temperatures and low moisture content. Therefore, January temperatures are 6-200C lower than mid-latitude ones. The lowest temperatures in January are typical for the northeastern part of the Central Siberian Plateau (-42...-430C). There is little precipitation in winter, about 20-25% of the annual amount.

Summer is relatively warm. Total solar radiation in July in the north reaches 12-13 Kcal/cm2, in most of the territory – 13-14 Kcal/cm2.

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In summer, due to warming up, low pressure is established over the territory. Air masses from the Arctic Ocean rush here, and westerly transport intensifies. But cold Arctic air, arriving on land, very quickly transforms (warms up and moves away from the saturation state) into continental air of temperate latitudes. July isotherms run sublatitudinally within the Central Siberian Plateau; this pattern is obscured by the influence of relief. The high hypsometric position causes less surface heating, so in most of its territory the average July temperature is 14-160C and only in the southern outskirts reaches 18-190C (Irkutsk 17.60C). As the altitude of the area increases, summer temperatures decrease, that is, vertical differentiation can be traced on the plateau territory temperature conditions, especially clearly expressed on the Putorana plateau.

The climate continentality naturally increases in east direction, especially in the northern part. Thus, the average air temperature in January at the northwestern limit of the zone is –320С, and at the eastern limit –380С, average July temperatures are +14 and +180С. at the southern border, the January average is 260C, and the July average is +180C. Average temperatures for the year are negative everywhere: at the northern border - about -100C, and at the southern border - about -40C. In the easterly direction the quantity decreases atmospheric precipitation from 500 to 250 mm, as well as evaporation from 250 in the southwest to 150 mm in the northeast.

The cooling of the continent in winter creates stable anticyclonic weather with severe frosts, low wind speeds and an abundance of calm conditions with moderate, and in other years, thin snow cover. An anticyclone begins to form in October, reaches its maximum in January, and collapses in March. The surface layers of air are intensively cooled, sometimes becoming colder than Arctic air masses. Throughout the entire territory, they can annually drop to -50, and sometimes to -620C, once every 15-20 years in January they increase to 3 and even to 00C, but there is no thaw.

Winter moves from the northeast to the southwest, where it lasts a total of 5 months. Characterized by stable temperature inversions with an increase of 1-30C for every 100 meters of altitude. In this regard, “lakes” of cold form in depressions not only in winter, but also in transition seasons. Therefore, plants in depressions suffer from frosts, while more productive and species-rich forests grow on hills and slopes compared to forests in depressions.

When the temperature drops below –350C, frosty fogs usually appear over populated areas - condensation of water vapor occurs. Fogs rise up to 40-50 meters, and sometimes up to 100 meters. The maximum annual cloudiness varies in November with up to 25 cloudy days. The sunniest month is March, when there are no more than 14-15 cloudy days.

Over a long period of almost six months cold period only about 15% of the annual precipitation falls. Snow lasts from October to May (from 250 days in the northwest to 230 days in the northeast and 185 in the south). Its distribution largely depends on the topography. If in the valleys its thickness does not exceed 30-40 centimeters, then on the hills it reaches 60-80 centimeters. In general, the greatest thickness of snow cover is observed in the Katanga basin in accordance with November snowfalls. Snow cover growth continues until January, then slows down. This depends on the increase in snow evaporation on sunny days. Persistent and severe frosts with little snow cover create conditions for maintaining, and in some places increasing, permafrost in soils.

The transition from winter to spring in the southern part of the zone is usually abrupt with a significant difference in low nighttime and high daytime air temperatures, especially on cloudless days. Sometimes, when warm air masses are transported from Central Asia, positive average daily temperatures are observed already in the first ten days of April. However, frosts occur until June.

In spring, air humidity is minimal (50-60%) and the least cloudiness of the year. In combination with not big amount precipitation (about 12% of the annual amount), droughts occur, especially in the southern part. This contributes to the dominant distribution of larch. Spring is also the windiest time of the year with fickle winds that change direction. Their speed often exceeds 15m/s. The snow, which has evaporated considerably during sunny March, melts quickly, with the exception of elevated shady places. But constant night frosts inhibit the thawing of soils, which prevents them from being moistened with melted snow water, which quickly slides into rivers without benefit for future harvests.

Preferential transfer of air masses to warm part years - from the west. Cold masses of it come from the north less often. Cyclonic activity is developing. Cyclones usually bring rain, except those that originate in Central Asia. However, the influence of the latest sharp cyclones is limited only to the southern part of the zone. Cold arctic air flows into the rear of western cyclones, causing cold snaps and even frosts.

The frost-free period naturally shortens from west to east and from south to north. Its average duration in the valleys of the southern rivers is 90-100 days, in the northwest - 70 days, and in the northeast - no more than 60 days. Daytime temperatures in summer are quite high everywhere and often exceed 300C. evaporation increases greatly. Cyclonic activity sharply increases the amount of precipitation. In 2-3 months, more than half of the annual amount falls, maximum in July - the first half of August.

Autumn, like spring, is very short and comes immediately, turning from warm summer days to constant night frosts. Everywhere at the beginning of autumn the weather is usually dry and clear. By the end of autumn, cyclonic activity subsides. An anticyclone begins to form. Frequent frosts occur at the end of August. In the valleys of small rivers, frosts occur at the end of August. In the valleys of small rivers, frosts occur at the end of August. In the valleys of small rivers, frosts begin almost a month earlier than in the valleys of large ones. In October-November the cloudiness is the greatest of the year, but the fogs decrease, the maximum of which occurs in August-September. In different years, the change of seasons of the year deviates up to two weeks in one direction or another.

As a result, we can conclude that the climate of the Central Siberian Plateau is formed under the influence of solar radiation arriving at the earth’s surface, the circulation of air masses and moisture circulation, as well as the underlying surface. The close interaction of these factors determined the formation of a sharply continental climate with cold long winters, low precipitation, relatively hot and humid summers, short transitional hot and humid summers, and short transition periods from winter to summer.

Inland waters

The largest rivers of Russia - the Lena, the Yenisei and their numerous tributaries - flow through Central Siberia.

The watershed between the Yenisei and Lena runs along the Central Siberian Plateau from south to north. In the northern part of the plateau, a watershed stretches from west to east, separating the rivers Pyasina, Khatanga, Anabar and Olenek from the headwaters of the tributaries of the Lower Tunguska, Kureika and Vilyuya rivers. All rivers carry their waters to the Laptev and Kara seas. Some rivers begin in the mountains, in the middle reaches their valleys have a transitional character and, finally, in the lower reaches they enter the plains and become typical lowland rivers. These include the Yenisei, Lena and the left tributaries of the Angara, Uda, Oka, Irkut and others. Other rivers - and most of them - begin on the Central Siberian Plateau. Their upper sections approach lowland rivers. In the middle reaches they cut deeply into the plateau, flowing through a narrow rapids valley, and in the lower reaches they become flat (for example, Podkamennaya and Nizhnyaya Tunguska, Vilyui).

Large rivers flow within the permafrost through the taiga. The headwaters of the rivers are located in the southern regions: here they have many tributaries that bring large amounts of water to the main rivers. The rivers are fed by rain and snow; part of the water in the rivers comes from the melting of ice and permafrost. Ground nutrition is insignificant. Spring-summer flood. During 4-6 warm months, more than 90-95% of the annual runoff occurs. The minimum flow of all rivers is observed in winter. Due to the long cold winter, ice cover on the rivers is very long. For example, in the northern part Irkutsk region the rivers freeze in the first half of November and open at the end of April. In winter, as a result of weakened flows and low temperatures, some rivers freeze. Water enters frozen sections of rivers from the upper reaches and spreads over the surface of the ice, forming powerful ice dams. At the same time, there are polynyas where powerful groundwater springs emerge, for example on the Lena River below Kachug. The freezing of Central Siberian rivers occurs in a very unique way. Ice first forms not on the surface of the water, but at the bottom on supercooled pebbles, and then rises to the surface. Freeze-up on rivers occurs in October, and on southern rivers - in early November. The ice thickness on the rivers reaches 1-3 meters. Small rivers freeze to the bottom.

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All large rivers are important transport routes and are used for shipping and timber rafting. The Angara River is navigable from Lake Baikal to the city of Bratsk and in the lower reaches - from the mouth upward at a distance of 300 km. The Lower Tunguska is a floatable river, navigable from the village of Turukhansk to the village of Tura. The Podkamennaya Tunguska is navigable only in its lower reaches.

Rivers have enormous reserves of electricity. A cascade of powerful hydroelectric power stations has been built and is being built on the Angara and Yenisei, but these large stations also have huge reservoirs, although with the relatively great depth and narrowness of the valleys they flood and less land than their "counterparts" on the Western plains. And yet, about 5 ½ thousand went under the waters of the Bratsk Sea, and a little less than 2 thousand km2 under the waters of the Ust-Ilimsk Sea. The Bratsk Sea stretches along the river for almost 550 km, and its bays that penetrate up the Oka River and its tributary - another 370 and 180 km, respectively. The Ust-Ilimsk reservoir raised the Angara by 300 km. in length, and the bay in the lower reaches of the Angarsk tributary of the Ilim turned out to be shorter by only 1 km. Still, the width of the new “seas” is significant. Large reserves of timber, primarily timber timber, were saved from flooding; timber was removed from more than 3 thousand km2. But the part of the forest that remains uncut down harms water bodies. As wood decomposes, it depletes water, and the lack of oxygen increases winter fish kills.

The Central Siberian Plateau has a well-developed river network. This is due to the significant elevation and difference in altitude of the territory, fracturing of rocks, a long period of continental development, the waterproof effect of permafrost, and deep and long-term ozone freezing of soils.

Permafrost not only prevents moisture from seeping into the ground, but also reduces evaporation due to the low temperature of river and groundwater. All this determines the features of the water balance - an increase in the table and, above all, its surface component and a decrease in evaporation compared to similar latitudes of the Russian Plain and Western Siberia.

The rivers are rich in a variety of fish. The main commercial species are sterlet, sturgeon, omul, whitefish, and grayling. Salmon fish make up 97% of the catch. Largest quantity These fish are concentrated at the mouths of the Yenisei and Lena rivers.

Soils, vegetation and fauna

Due to the appearance of perennial soils in the eastern Yenisei Ridge, soil formation is noticeably different from the western territories. The soil profile is more often loosened from the western territories. The soil profile is often loosened by the seasonal introduction of ice, causing its mobility.

The podzolic process is suppressed and occurs mainly on deeply thawed sandy clay soils, especially on river terraces. In the interfluves, soils are formed on massively crystalline or woody sedimentary rocks. As a result of orthoeluvium, the usually rocky amount of fine earth rapidly decreases with depth and height and becomes highly gravelly.

Due to the low-temperature substrate, the humification of litter proceeds extremely slowly, and the organocumulative horizon A1 becomes coarse-humus and often peaty. Easily soluble substances, and especially fulvic acids, are quickly washed out of it. The looseness and gravelly content of the soil profile accelerates the migration of most substances, including silica. Humus is found throughout the soil profile, although in lower proportions. If in the upper part its content reaches 8-10%, then at a depth of 50 cm it is about 5%, and at a depth of 1 meter there may be 2-3% humus.

The A2 podzolic horizon is not always formed, especially in the northern half of the Central Siberian taiga. In general, podzolization here is typical on those parent rocks that contain light, weathering-resistant minerals - quartz, feldspar, micaceous silicates, i.e. mainly on sands and Mesozoic sandstones, developed precisely in the southern half of the plateau. But a podzolic or simply brightened horizon is never thicker than 3-5 cm; it is usually underlain by a bright brown horizon. This is due to the leaching of iron and fulvic acids. With depth, humic substances gradually precipitate around mineral grains in the form of humus-iron oxide compounds, coloring the soil brown. The brightness of the color decreases downwards, although the glandular compounds increase. The slight differentiation of the soil profile is influenced by the frozen screen, which moistens the soil during the growing season. The high content of fulvic acids causes a strongly acidic reaction of the soils with a pH of the water extract of 4-6. A small amount of humus and high acidity do not ensure soil fertility.

In the south, in the Angara River basin, clayey, slightly podzolic and sod-forest soils without a podzolic horizon are more common. A dark gray upper humus horizon and a transitional horizon to the parent rock are distinguished. In soils on traps rich in sesquioxides, where humic acids predominate over fulvic acids, calcium and magnesium are leached, and an iron film is formed around the primary minerals, inhibiting podzol formation. Such soils are called soddy-iron-aluminum soils.

On the carbonate rocks of the lower Paleozoic plain there are soddy-carbonate soils with a poorly differentiated profile, but with a dark gray humus horizon, containing 5-6% humus and about 9% calcium carbonate. Humic acids predominate in humus. The reaction is neutral or even slightly alkaline.

In the northern taiga, a new type of soil on traps - granuzems - has recently been studied. They are formed under conditions of a sharply continental climate on rocks that, when weathered, produce minerals with framework structures, pyroxenes, and glasses, under which clay minerals are not transformed. Rapid physical crushing promotes the accumulation of amorphous compounds of iron and aluminum and the rapid removal of products of the interaction of humic acids with minerals. A thin soil (about 20 cm) is formed with an unexpressed differentiation into genetic horizons, a chemical composition close to the parent rock, but with a high humus content of the fulvate composition and unsaturation of the absorbing complex.

Vegetation.

The vegetation cover of the taiga zone, which occupies more than 70% of the territory, has the most unique character. Despite this relative homogeneity and the vast spaces occupied by the taiga, it is not always the same. Differences in the thickness of the permafrost layer, in appearance, in drainage and other factors create some diversity in the plant world.

Within Central Siberia, light coniferous forests of Siberian larch (in the west) and Dahurian larch (in the east) predominate. The dark coniferous taiga is pushed to the extreme western regions. Warm and not very humid summers cause more significant advance of forests to the north than anywhere else.

Animal world

The fauna of Central Siberia differs from the fauna of Western Siberia: it is more ancient; the sharp continentality of the climate contributes to the large movement of taiga species to the north in summer period; In harsh climatic conditions, the hair of fur-bearing animals acquires special splendor, tenderness and silkiness.

Taiga has a more diverse and rich fauna. Common predators Brown bear, wolverine, fox, weasel, ermine, sable. Wolverine lives everywhere. This nocturnal predator lives under tree roots, in rock crevices, in soft soil and in snow. Colonel with brown fluffy silky fur. It is widespread in the Vimoya basin in dense taiga with undergrowth. Sable is rare and is distributed in the rocky areas of the dense taiga. The lynx is the only animal from the cat family; its habitat is dense taiga forests. The most common ungulates in the taiga are elk and musk deer, and bighorn sheep are found on the Putorana Plateau. Maral and roe deer are common in the southern part of the pre-Denisei taiga.

Rodents are numerous in the taiga, especially the squirrel, which occupies a prominent place in the fur trade; It is found throughout the territory, but its main habitat is the central dark coniferous taiga. Other common rodents include the chipmunk, the mountain hare, and the vole. Common birds include hazel grouse, white partridge and many others.

Since 1930, muskrats have been released into the Irkutsk region. Its habitats are ponds, slow-flowing rivers, where there is a lot of wetland vegetation. In the western part of the Irkutsk region, the brown hare and American mink were acclimatized.

It is important to note that many animals of Central Siberia are wrapped in warm coats of fur and feathers, especially necessary in winter; they are much larger than their relatives living in milder climates, which is an advantage in conditions where it is necessary to keep warm (the larger the animal, the less surface that loses heat relative to its size).

Thus, the formation and distribution of soils, vegetation and fauna throughout the plateau is greatly influenced by its specific harsh, sharply continental climate and the associated almost universal distribution of permafrost. Permafrost preservation is favored by low average annual temperatures and the peculiarities of the cold period inherent in this climate: low temperatures, low clouds, promoting night radiation.

The diversity of the soil cover of the Central Siberian Plateau is closely dependent on the heterogeneity of rocks, topography, moisture conditions, temperature conditions and the nature of vegetation. The species composition of animals, their number, lifestyle, and external color depend on the characteristics of the surrounding geographic environment.

Natural resources

The territory of the Central Siberian Plateau is rich in natural resources, it is especially endowed with minerals, hydropower and forest resources.

Thus, in the west of the Siberian Platform there are dislocated Riphean rocks (crystalline schists, gneisses, marbles, quartzites), here is one of the largest iron ore basins in Siberia - the Angara-Pitsky - located in the Yenisei Ridge; it is confined to a large synclinorium. Iron ores of sedimentary origin are noticed in the upper Proterozoic strata.

One of the largest coal basins in Russia is located here; its coal-bearing strata are classified as the Carboniferous and Permian systems. Under the influence of trap intrusions, some of the coals turned into high-quality graphite. The largest graphite deposits are concentrated in the lower parts of the Kureyka and Lower Tunguska river basins.

The Lena coal basin is located in the Vilyui syneclise and the Verkhoyansk trough.

Most of the Central Siberian Plateau is covered with taiga, including the Angara region which belongs to the forest surplus zone.

The fauna is rich in game and fur-bearing animals, for which Central Siberia occupies a leading place in the production.

The rivers of the Central Siberian Plateau have significant hydropower potential, for example, on the Angara River there is the Ust-Ilimsk Hydroelectric Power Station (4.3 million kW) and the world's largest Bratsk Hydroelectric Power Station (4.5 million kW), as well as on the Vilyui River - the Vilyuiskaya Hydroelectric Power Station.

Thus, the territory of the Central Siberian Plateau is provided with all types of natural resources, as a result, the following industries are developed in the region’s economy: fuel, non-ferrous, forestry, energy, fur.

Current state of landscapes and geoecological problems, possible ways to solve them

The economic basis for the development of the economy of Central Siberia is bringing industry closer to sources of raw materials. But the development of natural resources in harsh conditions Siberian climate high costs and careful attitude to nature in the process of exploiting its resources. In the last decade, more and more centers of local changes in nature have appeared during the extraction of minerals during transport and energy construction.

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Man actively invades nature and often changes the permafrost regime, which entails not only a change in soil and vegetation cover, but often also in the relief. These changes turn out to be irreversible, although they do not yet cover large areas. A striking representative of areas of human influence on nature is the Angara basin. To preserve unique and typical natural complexes and to protect animals, the Ust-Lena Nature Reserve was created in 1985 in the lower reaches of the Lena on an area of ​​about 1.5 million hectares, and in the Tunguska province - the Central Siberian Nature Reserve with an area of ​​slightly less than 1 million hectares.

It is important to preserve and protect as much as possible the Central Siberian taiga, not only for ethical and moral reasons, but also unique environment habitat, and also because, apparently, coniferous forests play a significant role in regulating CO2 reserves in the Earth’s atmosphere. This has become clear from recent research. The regeneration of the taiga is painfully slow. When layers of soil are removed, permafrost rises to the surface and prevents new trees from growing. It is now obvious that it is human impact that is causing the most dramatic changes in the taiga ecosystem.

Large scale mining iron ore, gold and minerals have left their mark on large areas of the region. Roads, settlements and all infrastructure have completely changed the local environment. Moreover, steel mills and pulp and paper mills seriously pollute the air.

Impact factors include:

deforestation;

water and air pollution;

Forest fires;

roads, dams, hydroelectric power stations, pulp and paper mills, metallurgical plants, mining and so on.

The pine and pine-deciduous forests of the Angara basin are especially valuable, where over 35 million hectares are concentrated. Pine forests.

Forest is an important physical and geographical factor that creates a special climate, retains moisture, and weakens wind speed. The vast majority of the territory of the Central Siberian Plateau belongs to forest surplus areas.

Today, the anthropogenic pressure on the fauna of Central Siberia has increased many times over, although today we can be proud of the world leadership in the production of valuable fur-bearing animals, a variety of birds and river fish, but soon without the organization of cultural hunting and fishing farms, without the creation of reserves and reserves, nothing of this will not be.

Physico-geographical zoning of Central Siberia

Natural areas

Throughout Central Siberia there are 3 zones: tundra, forest-tundra and taiga. The taiga is most fully represented, occupying 70% of the area. The Central Siberian Plateau includes only forest-tundra and taiga.

The forest-tundra stretches in a narrow strip (up to 50-70 km); The border of the zone runs along the northern ledge of the Central Siberian Plateau.

The climate of the zone is assigned to B.P. Alisov to subarctic with a predominance of continental air of temperate latitudes in the cold period and transformed arctic air in the summer. The combination of a polar position with continentality with insignificant radiation and the dominance of anticyclonic weather determines the severity of the winter period, which lasts about 8 months, from October to May. Snow cover lasts 250-260 days. Its thickness is 30-50 cm, increasing slightly to the west. In summer, the soil and ground layer of air warm up intensively. The average temperature in July is 12-13°C.

Quite high temperatures during the growing season and a decrease in the strength of winter winds favor the growth of not only grass and shrub vegetation, but also trees. The dominant tree species here is Dahurian larch. The vegetation cover of the forest-tundra is dominated by shrub thickets of lean birch, alder, and willow. Trees are scattered in individual specimens or groups.

The taiga zone stretches from north to south for more than 2000 km from the northern edge of the Central Siberian Plateau.

The specific features of the Central Siberian taiga, which sharply distinguish it from the taiga of Western Siberia, are the sharply continental climate and the almost universal distribution of permafrost, insignificant swampiness, the dominance of monotonous deciduous taiga and frozen-taiga soils.

The climate of the zone is sharply continental, with harsh winters with little snow and moderately warm and cool, moderately humid summers. Cold winter with persistent and severe frosts lasts 7-8 months. On the western slopes of the Central Siberian Plateau, the greatest amount of precipitation falls, which contributes to the formation of snow cover up to 70-80 cm thick. The relief and features of atmospheric circulation determine the variegated distribution of precipitation in the zone.

Zonal soils of the taiga are permafrost-taiga. In the central part of the taiga, the density of the tree layer and the height of the trees increase. In the undergrowth, in addition to shrubs and birch trees, there are bird cherry, rowan, elderberry, juniper, and honeysuckle. The grass and moss cover is typically taiga. Under the forests, acidic permafrost-taiga soils develop. Diversity increases in southern taiga coniferous forests. In the space of the taiga zone, intrazonal differences associated with the nature of the lithogenic base are clearly visible.

The distribution of forests across the territory is most influenced by an increase in the severity of winter and a decrease in the thickness of the snow cover from west to east. In this regard, dark coniferous spruce-cedar forests predominate in the Yenisei part. To the east they are replaced by dark coniferous-deciduous and pine-deciduous ones.

Physiographic provinces and regions

There are two main provinces on the territory of Central Siberia:

1. The province of mountain-glacial tundra and forest-tundra mid-mountains and moraine-sea plains occupies the northern part of Central Siberia. The province is characterized by significant differentiation of neotectonic uplifts. The greatest uplifts appeared in the folded-block mountains of Byrranga, where, in connection with the rise of the territory, local centers of ancient and modern glaciations arose. Moraine-marine accumulative plains formed on the site of territories with minor subsidence and uplift. The province is located within the northern part of the Krasnoyarsk Territory and the north-west of the Yakut Autonomous Soviet Socialist Republic.

The Arctic deserts and tundras of Taimyr are the northernmost physiographic continental region of the Soviet Union. It occupies the northern half of the Taimyr Peninsula. The Byrranga Mountains extend from the Yenisei Bay to the Laptev Sea almost the length of the Caucasus (1000 km) and are divided into three parts: the western, located between the Yenisei Bay and the Pyasina River with altitudes up to 400 m; central between the Pyasina and Nizhnyaya Taimyra rivers with altitudes up to 700 m; the eastern part is the highest, the highest height reaches 1146 m. ​​The mountains gradually descend to the shores of the seas of the Arctic Ocean, forming a series of low hills, and fall steeply to the North Siberian Lowland. The ridges and massifs are separated by deep longitudinal and transverse river valleys. The mountains are composed mainly of Paleozoic rocks: in the north of the highlands there are outcrops of Precambrian (metamorphic shales of the Proterozoic) and acidic intrusions of pre-Paleozoic and Paleozoic age. The northern part of the highlands was created in the Caledonian folding, and the southern - in the Hercynian.

The relief is characterized by the widespread development of stone placers and a complex of exaration (“ram’s foreheads”, Kara, troughs) and frozen-solifluction forms. In the central and western parts, the mountain peaks are dome-shaped, and in the eastern part, dissected glacial relief predominates: moraines and outwash are common, located in low areas - highlands. There are numerous large snowfields and modern glaciers in the Byrranga Mountains.

Winter is severe with a negative radiation balance (from mid-September to April) and a predominance of severely frosty weather types. The duration of the cold period is about 290 days. The average January temperature is -30, -35° C. Snow cover lasts from September 15-20 to June 27, and its height in winter is 20-60 cm.

Summer is short and cold. Total radiation in July reaches 16 kcal/cm2. The average July temperature at Cape Chelyuskin is +1°C. Annual precipitation is about 200-300 mm. They fall approximately evenly throughout the year, the ratio of precipitation to evaporation is more than 1.33. The entire territory is located in the permafrost zone with minor seasonal thawing of the soil during the warm period and north of the bullet isoline of the sum of active temperatures.

In the highest part of the mountains, northeast of the lake. Taimyr, where up to 700 mm of precipitation falls at an altitude of 900 m, modern glaciation is developed. The area of ​​all glaciers is about 50 km2. The existence of glaciers and snowfields on the Byrranga Highlands should apparently be considered as altitude zone perennial snow and ice, since this is the highest part of the mountains, where the “365 level” comes close to the surface of the ridges.

At the foot of the mountains there are arctic tundras on hidden gley soils (in the northern foothills) and arctic tundra soils (in the southern foothills). In 13 southwestern foothills, moss, lichen and shrub tundras are developed on tundra gley soils.

Altitudinal zonation is expressed in the Byrranga Mountains as follows: at the foot of the northern slopes there is arctic tundra, and at the southern slopes there is arctic tundra and moss, lichen and shrub tundra; along the southern slopes, moss-grass tundras rise to a height of 200 m. Higher up the mountain slopes there are arctic deserts on cryptogley arctic soils. Even higher - sparse vegetation of screes and rocks, glaciers. Numerous finds of stumps and tree trunks (larch, birch, willow, spruce) in Quaternary deposits along the Upper and Lower Taimyr rivers, at the mouth of Pyasina and at Cape Chelyuskin (north of 76° N) indicate that forest vegetation covered Almost the entire territory of the Taimyr Peninsula and the northern border of the forest-tundra was 4-5° north of the modern one.

The North Siberian moraine-marine tundra lowland is located between the tectonic ledges of the Byrranga, Putorana and Central Siberian plateau mountains. In the west, the lowland merges with the West Siberian Plain, and in the east - with the Lena Delta. The hilly surface of the lowland has a height of 50-100 m. The maximum heights are about 225-260 m. From the Byrranga Mountains, individual ridges and hills with heights of 400-650 m enter the lowland. In the northeast of the lowland, two cuestas rise: Pronchishcheva (up to 315 m) and Chekanovsky (up to 529 m).

The coast west of the river mouth. Olenka continues to descend. This is evidenced by the estuaries of the Anabar and Khatanga rivers. To the east of the mouth of Olenek, rivers form deltas when they flow here, which indicates an uplift of the coast. River delta area Lena is 28,500 km 2. On many islands of the delta, peat bogs are developed, there are polygonal wedge ice and hydrolaccoliths.

The North Siberian Lowland formed on the site of submerged Hercynian structures of the Taimyr Peninsula, Mesozoic structures extending from the Pre-Verkhoyansk foredeep. The lowered folded structures form the marginal Khatanga trough, which is filled with sedimentary deposits of the Paleozoic, Mesozoic and Quaternary. Mesozoic deposits are carbon-bearing. Among the sedimentary rocks there are salt domes composed of Permian, Triassic sandstones, and Devonian rock salt (Nordvik).

The climate is arctic with moderately harsh, long winters and short, cool summers. In winter, anticyclonic weather prevails. The duration of the cold period is about 290 days. The average January temperature is about -30, -36°C, minimum -61°C. The average July temperature ranges from +4°C in the north of the lowland to +12°C in the south. The maximum temperature reaches +30° C. The annual amount of precipitation decreases from west to east from 300-350 to 200-220 mm, and in the Lena River delta about 100 mm falls. The zone is excessively humid: the ratio of annual precipitation to evaporation is more than 1.33. Sum of active temperatures 0-400°C, N=0-3.

The rivers Pyasina, Upper Taimyr and the lower reaches of Khatanga, Anabar and Olenek flow through the lowlands. Among the hilly-moraine sea plains and on the islands of the Lena Delta there are many shallow glacial and thermokarst lakes. Swamps are common in places: their depth is shallow, since the top layer of frozen soil thaws by 30-60 cm during the warm period.

In the North Siberian Lowland, moss-lichen and shrub tundras predominate; to the south, shrubby birch and willow tundras are common. The main soils are tundra gley. In the south of the lowland, swampy sparse larch forests appear on gley-permafrost-taiga soils. Siberian larch It comes from the west only to the sources of the Pyasina, and to the east of it the Daurian larch is widespread. Daurian larch moves along river valleys far to the north: in the river valley. Khatangi - up to 72° N. w. The northernmost section of the forest on globe located on the terrace of the Lukunskaya river (72°34" N). Northern border forests in the North Siberian Lowland during the period of the post-glacial thermal maximum passed significantly north of the modern one, approximately at the foot of the Barranga Mountains. To preserve the northernmost forest areas on Earth, it is necessary to organize a reserve in the river basin. Khatangi.

The northern taiga and mountain-tundra plateau of Putorana is located on the northwestern polar edge of the Central Siberian Plateau: its western and northern borders run along tectonic ledges, in places forming rocky walls 300-500 m high. The southern and eastern borders of the Putorana region are drawn along the border of the Zyryanka glaciation. Putorana is a huge dome-shaped mid-mountain uplift of part of the Central Siberian Plateau, the highest heights of which are concentrated in the center (1701 m). All the rivers begin there (Kotui, Kureika, upper reaches of Kheta), creating a centrifugal pattern of the hydraulic network and emphasizing the dome-shaped structure of the mountain system.

The Putorana Plateau was formed on the site of the lowered part of the Tunguska syneclise, the anticlinal zone and the marginal trough of the Baikal fold as a result of intense Quaternary uplifts. The plateau is composed of horizontally occurring sedimentary rocks of Paleozoic age and traps - volcanic rocks of Upper Permian and Lower Mesozoic age. In the creation of the modern relief, the determining factor was tectonic movements: pre-Quaternary and Quaternary splits of the latitudinal and meridian directions, as well as arched uplifts and subsidence in certain areas.

The main forms of relief are numerous elevated blocks along the split lines of the massif - ridges with flat rocky watersheds, separated by wide intermountain depressions, young erosional and glacial valleys. The mountain slopes drop steeply to deep intermountain depressions and to valleys created as a result of the activity of rivers and glaciers along the lines of Neogene, Paleogene and Quaternary rifts. The depth of the mountains reaches 800-1500 m. On the Putorana plateau in the Pleistocene, powerful ice sheets developed, which had a great influence on the formation of morphosculpture. Intermountain depressions are filled with glacial deposits and have a hilly-moraine topography with a large number of lakes dammed by moraines, as well as tectonic ones (lakes Lamo, Keto, Khantaiskoe, Glubokoe, etc.). On the slopes of the valleys, circuses and pits filled with snow are characteristic.

The Putorana plateau is located in the west of the Siberian region of the subarctic climate zone and is influenced by Atlantic and Arctic air masses and the Asian anticyclone. Therefore, there are significant differences in the climate of the western and eastern parts of the plateau. In the west of Putorana there is more rainfall and cooler summers than in its eastern half. Winter is long and very cold: the average temperature of the coldest month reaches -30, -38°C, the absolute maximum temperatures in the north are -58°C, and in the east -59°C. The snow cover lasts for about eight months. Summer is short, but moderately cool, in low areas the average temperature of the warmest month is from +12 to +14°C, and in the mountains, at an altitude of 600-1500 m, from +6 to +12°C. Maximum temperature was noted in the north +28°C, and in the east +31°C, in most of the region the sum of active temperatures was less than 400°C. The annual amount of precipitation in the west was 504 mm, and in the east - 300 mm. Humidity coefficient - 1.33, N = 3.

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The Putorana Plateau is located in the northern taiga subzone, where the western dark coniferous taiga touches the eastern larch taiga. Dark coniferous taiga with larch occupies intermountain basins and valleys, rising up to a height of 250-450 m.

Higher up are larch forests, which from a height of 450-500 m are replaced by larch woodlands and thickets of dwarf cedar. The mountain soils are permafrost-taiga, gleyic-acidic with signs of podzolization. Above 700-750 m there is a belt of alder, turning into mountain shrub tundra. From an altitude of 800-900 m, mountain tundras (lichen and rocky) are common. Below the solid rocky placers, mountain-tundra and mountain-arctic soils are developed.

The Anabar basement taiga and mountain-tundra upland is located in the upper reaches of the Anabar and Olenek rivers, on the Anabar shield, which is expressed in relief as a dome-shaped uplift. Its maximum heights reach 905 m in the center. The watersheds look like numerous massifs with smooth dome-shaped peaks.

The folded Archean crystalline base of the Anabar shield is elevated in the central part, and along the edges the surface of the basement declines, overlain mainly by limestones and sandstones of the Cambrian and Ordovician. In the southwest of the region there are outcrops of sedimentary Silurian and Permian deposits and trap covers. Between the Anabar Upland and the Putorana Plateau there is the Kotui swampy trap plateau. On the Anabar Upland and the Kotui Plateau, traces of ancient glaciations were discovered in the form of narrow ridges composed of boulder loams and sand and gravel material. Glaciation was inactive. The watersheds are flat with dome-shaped tops; valleys carved out of easily eroded rocks, floodplains with ancient terraces, and in some areas (where crystalline rocks emerge) the valleys are narrow with rapids and rifts. The main types of relief of the Anabar shield are basement plateaus with glacial and nival treatment; Along the edges of the Anabar shield, in the area of ​​development of Paleozoic rocks, erosional strata-tiered, water-glacial lacustrine and alluvial plains and a trap plateau were formed.

The climate is subarctic with cold, long winters. The average temperature in January is -38, -43°C. In the basin of Lake Essey, the minimum inversion temperature was recorded at about -70° C. Summer is moderately cool: the average July temperature is +12, + 14° C. The sum of active temperatures is 700-400° C or less (in the mountains). Humidity coefficient - 1.33-1.00. Annual precipitation is about 300 mm. The area is excessively wet.

The main part of the territory is covered with northern taiga forests of Daurian larch and mountain larch woodlands on gley-permafrost-taiga and mountain-permafrost-taiga soils. In the south, in the upper reaches of the river. Olenek, permafrost-taiga carbonate gravelly soils are developed on sedimentary rocks of the Lower Paleozoic. Forests rise along the slopes of valleys and mountain ranges to a height of 500-700 m. Mountain tundras on mountain-tundra soils are developed higher up.

The Tunguska trap north and middle taiga plateau occupies the Lower Tunguska basin and the upper reaches of Olenek and Vilyuy between the boundaries of the Samarova and Zyryanka glaciations. The heights of the watershed plateaus are up to 981 m (N. Tunguska basin). River valleys are cut deeply. The surface of the foundation of the Tunguska syneclise and the southwestern slope of the Anabar massif is lowered to depths from 1000 to 4000 m and is covered by a thick layer of sedimentary rocks of the Paleozoic and Triassic, penetrated by traps. During the Maximum and Taz glaciations, the region was a marginal glacial zone and bottom and terminal moraine-glacial deposits were formed on the surfaces of the trap plateau and strata-stage plains. During the Zyryan and Sartan glaciations, the territory represented a periglacial region: in conditions of a cold climate, permafrost and treelessness, colluvial and permafrost processes took place; microrelief was formed - mounds, polygonal shapes, etc.

The region lies in the subarctic and temperate zone. The climate is sharply continental and humid. The average January temperature is about -28°C in the southwest and -38°C in the northeast. The average temperature of roofing felt is +15, +16° C. The greatest amount of precipitation in the west is 400-500 mm; in the east they gradually decrease to 300 mm. The sum of active temperatures is 600-1000° C. Humidification coefficient is 1.33-1.00, N = 6-10.

An increase in precipitation and the proximity to the West Siberian Plain predetermined the development of a more diverse species composition of middle and northern taiga forests in the southwest of the region. They consist of larch (Daurian and Siberian), spruce, pine, cedar with an admixture of birch. In the east, the forest is formed of larch with an admixture of birch. Under the forests in permafrost conditions, permafrost-taiga, mountain permafrost-taiga carbonate and podzolic soils were formed; The highest watersheds (800-900 m high) are covered with mountain tundra.

2. The province of extraglacial erosional plateaus and highlands and alluvial-lacustrine lowlands of the forest zone is located in the southern half of Central Siberia, beyond the limit of maximum glaciation. The province is characterized by intense differentiated neotectonic movements. Permafrost and accompanying permafrost-solifluction landforms are widespread. The province lies mainly in the southern part of the Krasnoyarsk Territory and in the southwest of the Yakut Autonomous Soviet Socialist Republic.

The Leno-Olenyok northern taiga plateau is located in the northeast of the Central Siberian Plateau, between the boundary of maximum glaciation and the mountains of the Verkhoyansk Range. The plain is located on the eastern slope of the Anabar massif, consisting of the Olenyok trough, Olenyok and Munsky uplifts. The depth of the foundation in the trough is about 1500 m, and in the uplifts - from 500 to 1000 m. The platform cover is formed by carbonate deposits of the Cambrian and Ordovician. Quaternary rocks on watersheds are dominated by colluvial - solifluction and eluvial strata, and along river valleys - alluvial and deluvial-colluvial. The plateau is dissected by deep valleys with flat watersheds. In areas of fractured rocks, valleys sharply change their directions. The surfaces of carbonate rocks are dissected by modern ancient karst forms. Permafrost-solifluction forms are widespread throughout the territory.

The climate is subarctic with cold, long winters: the average January temperature is -40, -42°C. The duration of snow cover ranges from 220 days in the south of the region and more than 240 days in the north. The average July temperature is from +12 to +16° C. The sum of active temperatures is 400-1000° C. The territory is slightly arid, the humidification coefficient is 1.00-0.77. Annual precipitation is more than 200 mm.

The region is located in the northern taiga subzone of sparse larch forests. The sparse larch stand in the north - in the forest-tundra - is evenly distributed. On the Oleneksky rise, on elevated plateaus north of 70° N. latitude, the altitudinal zonation is manifested: from about a height of 350 m, the peaks of the plateau are covered with mountain tundra on mountain-tundra soils, and along lower watersheds and river valleys the larch forest extends far to the north. In the southern part of the Leno-Olenyok watershed, on the slopes of southern and southwestern exposure, relict steppe grass-forb areas have been preserved.

The main soils of the region are gley-permafrost-taiga and at the outcrops of carbonate Lower Paleozoic permafrost rocks.

notaiga carbonate.

The Angara-Tunguska trap mid- and southern taiga plateau is located in the basins of the Angara, Podkamennaya and Nizhnyaya Tunguska rivers and the upper reaches of the Lena, in the southern part of the Tunguska syneclise. The plateau is composed of Paleozoic and Lower Mesozoic sedimentary rocks with a wide distribution of traps. The Quaternary cover is formed by eluvial-deluvial, deluvial-solifluction and alluvial processes.

The relief is dominated by erosive strata-tiered and trap plateaus, separated by deep valleys. Karst forms are developed in easily soluble rocks, especially in the southern Angara region, where craters, caves, dry and blind valleys arose in gypsum, limestone and dolomite. The traps had a great influence on the relief forms of the entire territory: on watersheds they form a raised plateau, in the valleys they form canyon-like forms and rapids.

The large fracturing of the traps contributes to the accumulation of groundwater that emerges on the slopes of river valleys.

The climate is temperate, continental. Winter is very cold and moderately harsh. The average temperature in January is from -20 to -30°C, and the minimum is -58°C. Summer is warm: the average July temperature is + 16, +18° C. The sum of active temperatures is 1000-1600° C. The humidification coefficient is 1.00-0.77. The greatest amount of precipitation (about 400 mm) falls in the west of the region, to the east it decreases to 300 mm, N=10-16.

According to morphology, the Angara valley is divided into three parts: the upper one - from the lake. Baikal before the river flows into it. Oka, 680 km long, where the river flows in a narrow valley with rocky banks; the middle one - from the Oka River to the confluence of the Ilima River, 290 km long, where the Angara passes through traps, forming the rapids Podkamenny, Padunsky, Dolgiy, etc.; the lower one - from the Ilma River to the Yenisei, 860 km long, where the Angara River also flows through the traps, but the rapids in these sections are much smaller. The regime of the Angara largely depends on the regime of the lake. Baikal. The Angara is characterized by high water content and smooth level fluctuations, especially in the upper reaches. In the spring, there is not a flood on the Angara, but a decline in water. With the onset of freeze-up, the water level rises and remains high throughout the winter. In the spring, when the ice jams disappear, the water level begins to decrease.

The water temperature in summer at the source (in August) is about +8.4° C. Downstream it rises, reaching + 16.7° C at Bratsk (in August). There is often a line of thick fog over the Angara, since the water is colder in summer ambient air, and it is warmer in autumn. In the north of the region, larch forests with an admixture of spruce, cedar and pine grow on frozen-taiga acidic soils. To the south of the latitudinal segment of the Angara stretches the southern light-coniferous taiga, dominated by pine with an admixture of larch, cedar, spruce and birch on sod-podzolic soils, among which sod-carbonate soils are found.

The Yenisei basement taiga ridge consists of individual ridges and massifs with heights of 800-1100 m. The maximum peak is Enashimsky Polkan (1104 m). This ridge is formed by anticlinal and synclinal structures of the Baikal folding and is composed of Precambrian shales - gneisses and granites. In the northern part of the ridge, sandstones and limestones of the Lower Paleozoic lie on Precambrian rocks. Above the mouth of the Podkamennaya Tunguska, the Yenisei ridge is cut through by the Yenisei. To the west of the Yenisei valley it plunges under the sedimentary deposits of the West Siberian Plain. In places where the breakthrough occurs, the Yenisei valley is narrow, and there are Osinovsky rapids in the riverbed. The largest river of the Yenisei Ridge - Big Pit - cuts through it in the south and flows in a narrow, deep valley. The basement watershed elevations of the ridge are flat and ridged, swampy in places, and many rivers flow from the swamps. The slopes are strongly dissected by river valleys, the depth of which often reaches 180-200 m.

The climate is characterized by cold winters with high snow cover (up to 90 cm) and moderately warm summers. The average temperature in January is about -20, -25°C, and in July +16°C. The sum of active temperatures is 1200-1600°C. Annual precipitation 550-700 mm; The area is wet, the humidity coefficient is 1.33-1.00. The ridge is covered with dark coniferous mountain taiga forests consisting of spruce, fir, cedar with an admixture of larch, pine and birch. Mountain permafrost-taiga soils form under the forests.

The Leno-Vilyui accumulative and strata middle taiga plain occupies the zone of subsidence of the foundation of the Siberian Platform: the eastern part of the Angara-Lena trough, the Vilyui syneclise and the Pre-Verkhoyanok trough. The largest rivers of Central Siberia - Lena, Aldan, and Vilyui - flow across the surface of the plain in terraced valleys. The highest altitudes are located on the outskirts of the region and reach 400-700 m, and the lowest are in the Vilyuy and Lena valleys - about 50 m and below.

The Vilyui syneclise and troughs are filled with terrigenous, salt-bearing and carbonate sediments of the Cambrian, Ordovician and Silurian, a thick layer of continental and marine Jurassic and Cretaceous sediments (sands, loose sandstones, clayey shales with layers of brown coal), in the Lower Aldan depression there are coal-bearing and sandy lacustrine-alluvial Neogene deposits. Particularly widespread coal accumulation occurred during the Lower Cretaceous era. The thickness of Mesozoic rocks reaches 200-300 m. The synclinal occurrence of Mesozoic rocks is complicated by folds, which increase as they approach the Verkhoyansk Range. Among the loose Quaternary sediments (lacustrine-marsh, loess-like, etc.), lenses of fossil firn or lake ice are preserved; they melt and subsidence is formed, filled with water.

A large number of lakes are scattered throughout the Leno-Vilyui lowland, on watersheds and in valleys. For economic use, the local population drains lakes into rivers. In the lake basins, beautiful meadows are formed, used for mowing, and pastures, the so-called alas.

The climate is sharply continental. In winter, cold air flows into the Leno-Vilyuiskaya lowland, here the air cools and an anticyclonic weather regime develops. Therefore, winter is very harsh and cruel, with the temperature of the coldest month -35 -45°C, moderately snowy. The duration of snow cover is about 220 days, and the height is 20-40 cm. Summers are warm, slightly dry and arid; the average July temperature reaches +18°C in Vilyuysk, and +18.8°C in Yakutsk. The sum of active temperatures is 1200-1400°C. The annual precipitation decreases from west to east: in Vilyuysk it falls 2.46 mm, and in Yakutsk - 192 mm, humidification coefficient -0.77 -0.55, N=15 - 26.

The entire territory is covered with larch forests, under which predominantly permafrost-taiga carbonate soils are developed, forming on carbonate rocks. In the Leno-Vilyui Lowland, forests are often swampy. Larch-pine and pine forests are common on the sandy terraces of the valleys. Under the forests, frozen-taiga pale (neutral) and solodized soils formed. On the terraces of the valleys of the Lena and Vilyuya rivers, among the larch taiga, there are patches of meadows, among which alas are especially unique. The vegetation of the alas consists of fescue, bluegrass, sedge and a large number of forbs. Some of the alases are covered with saline meadows (turans), formed on the site of lakes.

The vegetation of salt marsh meadows consists of saltworts. There are salt licks and solods. Steppe meadows with dark-colored meadow-chernozem loamy soils containing up to 12 - 17% humus are common on the Lena terraces above the floodplain. Their vegetation cover is formed by feather grass, fescue, thin-legged grass, and xerophytic forbs: Siberian edelweiss and speedwell. Among the wall species, there are local Siberian species, whose origin is associated with the mountainous regions of Siberia, and Mongolian species, which came mainly from Central Asia during one of the xerothermic periods.

The Aldan basement taiga mountain-tundra highland occupies the southeastern part of Central Siberia, between the Lena River and the Stanovoy Range. In the Aldan Highlands, the ridges rise to 1800-2300 m.

The Aldan basement highlands are a reflection in the relief of the Aldan shield, which is composed of crystalline and metamorphic rocks of the Archean. They are covered on the surface by sedimentary rocks of the Lower Cambrian and continental sediments of the Jurassic and Lower Cretaceous. The Aldan shield is riddled with intrusions of various ages. Mesozoic deposits on the shield lie in the Prestanovoy trough, which represents a zone of deep subsidence of the foundation, where the thickness of Mesozoic coal-bearing sediments reaches up to 750 m. In the south of the trough there is a large fault separating the Stanovoy Range from the Aldan Highlands. In relief, the fault line is expressed as a ledge.

To the north, Archean rocks are subducted beneath predominantly carbonate Lower Cambrian strata that gently dip to the north. On the surface of the Cambrian there are patches of Jurassic sediments. The slope of the Aldan shield in relief is expressed by the Leno-Aldan erosional layered plateau, on which the predominant heights are 500-600 m, with some areas reaching 700-1000 m. Ancient and modern karst processes occurring in Cambrian rocks are widespread on the plateau. In the Pliocene-Quaternary, the Aldan Highlands experienced greater uplift than the Leno-Aldan Plateau. The uplifts caused increased erosion and dismemberment of the territory.

The rivers are deeply incised: they have up to 4-8 accumulative and basement terraces (Olyokma, Lena, Aldan). Within the region there are four leveling surfaces (the highest - 1000-1300 m, the lowest - Lenskaya - 300-400 m). Traces of ancient glaciations are expressed on the ridges of the Aldan Highlands with absolute elevations above 1200-1300 m.

The climate is cold and cold-temperate with an average January temperature of -32, -40°C, with prolonged snow cover of 220-240 days. Summer on the Leno-Aldan Plateau is warm, humid and semi-humid, the average July temperature is above +16°C; on the Aldan Highlands - cool and excessively humid; The average temperature in July is about +12°C. The sum of active temperatures is 1200°-1400°C, the humidification coefficient is 1.33-1.00. Annual precipitation is 200-300 mm on the Leno-Aldan plateau and 400-500 mm on the Aldan highlands, N = 9-4.

The Leno-Aldan Plateau is dominated by mid-taiga larch forests on permafrost-taiga fawn (neutral) and solodized soils. Along the river valleys there are larch-pine forests and patches of meadow steppes (Amga Valley). The Aldan Highlands are dominated by mountain larch and larch-cedar forests on mountain permafrost-taiga soils and mountain permafrost-taiga carbonate soils. Forests rise along the slopes of the ridges to a height of 1200-1300 m. Above, the slopes and peaks are covered with mountain tundra on mountain-tundra soils.

The Sayan southern taiga and forest-steppe erosion plateau with a cover of loess-like rocks lies in the foothills of the Eastern Sayan. The plateau reaches its greatest height in the foothills (550-760 m). To the north and northeast, the territory drops to 500 m. The lowest parts of the region (200-240 m) are located in the area of ​​the city of Kansk. The region is located on the southern edge of the Siberian platform - in the Irkutsk amphitheater, where three geostructures are distinguished: the Sayano-Prienisei and Pribaikal-Lena syneclises and the Angara anteclise separating them. Along the northern foot of the Eastern Sayan stretch Mesozoic depressions - the Cape and Irkutsk, filled mainly with terrigenous coal-bearing deposits of Jurassic age; The Cape Depression continues to the west, beyond the Yenisei, and is united by the common name Kansk-Achinsk Depression.

Coal and lignite deposits of the Kansk-Achinsk and Irkutsk basins form the Kansk-Irkutsk coal-bearing province.

The climate is sharply continental, semi-arid: the amplitude of absolute temperatures is about 84°C (-51°C +33°C). Winter is very cold, quite snowy in the west and moderately snowy in the east with an average January temperature of -20.-25 ° C. Summer is warm, the sum of active temperatures is 1400-1600 ° C, the duration of the frost-free period is from 72 days in the northeast of the region to 106 -111 days in the Cape forest-steppe. Precipitation per year is 300-400 mm, the moisture coefficient is 1.00-0.77. Permafrost islands are rare.

Among the southern taiga pine forests there are areas of steppes and steppe meadows: their distribution is related to the dissected topography and the degree of moisture. Significant areas are covered with larch-pine forests on soddy-podzolic soils. Spruce-fir forests of the southern taiga type occupy the northern territories and are found in the valleys. Pine forests of forest-steppes on watersheds and slopes are sparse and have a high grass cover, birch forests with an admixture of larch cover the slopes of northern exposure, and sometimes watersheds.

Forest-steppes occupy the lowest areas of the plateau (Cape Basin) and the slopes of the valleys of the Oka and Angara rivers (Irkutsk and Balagan forest-steppe). The steppes are dominated by perennial turf grasses (fescue fescue, feather grass, wormwood granary) and forbs (speedwell and cinquefoil). Species composition The steppes of Central Siberia are somewhat different from the steppes of Western Siberia: many species are absent, for example meadowsweet, but mountain steppe species appear, for example edelweiss. Leached chernozems predominate, and on the outskirts - gray forest slightly podzolic soils. Meadow saline soils are developed in the ravines.

Conclusion

Based on the studied material, we can conclude that the Central Siberian Plateau is a complex formation in terms of relief and history of formation. Its territory contains both plateaus and mountains with steep river valleys and narrow watershed ridges. Thus, the Putorana Plateau is the highest part of the Central Siberian Plateau.

The Central Siberian Plateau is characterized by river valleys with well-defined terraces and numerous small valleys. The presence of terraces indicates slow movements earth's crust that took place on the plateau.

The climate is sharply continental. Permafrost is widespread everywhere. The formation of permafrost occurred during the Ice Age. Permafrost is a legacy of the Ice Age. The Central Siberian region has a rich material and raw material base, sufficiently prepared for industrial development. The water resources of the Central Siberian Plateau are one of the most valuable natural resources. Groundwater resources can be renewed in accordance with natural cycles characteristic of a particular region. climate zone, geological structure and landscape features of the territory.

Physico-geographical conditions, the significant extent of the Central Siberian Plateau, the complexity and dissect of the relief determine the diversity natural areas. Natural zones represented by forest-tundra and taiga are integrated ecological complexes that arise when plants and animals interact with the environment. Each zone is characterized by its own set of forms of plant life and a specific dominant form.

A week-long tour, one-day hiking and excursions combined with comfort (trekking) in the mountain resort of Khadzhokh (Adygea, Krasnodar Territory). Tourists live at the camp site and visit numerous natural monuments. Rufabgo waterfalls, Lago-Naki plateau, Meshoko gorge, Big Azish cave, Belaya River Canyon, Guam gorge.

Climate

The climate of Western Siberia is determined by the influence of three main factors: solarity, the humidifying role of the Atlantic Ocean from the west and the powerful winter anticyclone of Eastern Siberia from the east. Major climate changes occur in two directions: from north to south (increasing warmth) and from west to east (increasing continentality).

The complex terrain of the Altai-Sayan Mountains contributes to the creation of numerous areas with different climatic features - from warm and humid (the lower part of the western slopes and especially the southern shore of Lake Teletskoye) to dry and cold (the eastern slopes of the mountains and especially the valley steppes and semi-deserts of Altai).

To the east, the amplitudes of air temperatures in Western Siberia increase due to the winter months. To the south, low winter temperatures contrast with high summer temperatures. Average July temperatures range from +22°C in the far south to +4°C in the far north. The average December temperature in Kurgan is -14.8°C, and in Novosibirsk, located somewhat to the south, but significantly to the east, -16.2°C. Maximum daily air temperatures in Western Siberia range from +41 to +27°C, minimum - from -46 to -54°C.

The growing season lasts 175 days in the south and less than 100 days in the north. Spring passes quickly and is characterized by repeated returns of cold weather. Autumn is also short and cold. The first autumn frosts occur at the end of August - in September. In September, temperatures are usually positive everywhere. In October, air temperatures are either negative or close to zero; November is the coldest month of the year, especially in the northern regions.

The greatest amount of precipitation (on average about 500 mm per year) falls at the bend of the Ob riverbed between the mouths of the Irtysh and Tom. To the north and south, annual precipitation amounts decrease. Off the coast of the Kara Sea and on the nearest islands they are 170-160 mm, in the south 270-260 mm. In terms of climate humidity, the West Siberian Lowland occupies a middle position between the East European Plain and the Central Siberian Plateau.

The southern regions of Western Siberia are in the summer under the influence of dry winds blowing from the north, and sometimes hot winds coming from Central Kazakhstan and often bringing with them drought, which has an extremely negative effect on agriculture and the fruiting of tree species. This necessitates artificial irrigation and watering of a number of steppes in Western Siberia and the creation of a system of forest shelterbelts in areas located mainly south of the Siberian Railway. Monsoon-like changes of summer (northern) and winter (southern) winds form constant movements of air masses over the territory of the West Siberian Lowland. In addition to them, there are local wind systems associated with the orographic conditions of the area (river valleys, watersheds, mountain ranges, etc.). Wind speeds in different areas of the West Siberian Lowland are different. It is most significant on the sea coast: 7-8 m/sec on average per year. In the forest zone, wind speed decreases by half, but in the south, in the forest-steppe and steppe, it increases again.

In addition to the factors of the ratio of heat and moisture, in the climate of Western Siberia great importance has a snow cover, which regulates the depth of soil freezing and its temperature regime in winter. The thickness of the snow cover, in addition to the zonality and degree of continental climate, is also influenced by meso- and microrelief and the nature of vegetation. Soil freezing with light snow cover extends to a depth of 20 cm in mid-November, increases to 40 cm by the end of November and reaches 80 cm in early December.

Western Siberia is a country with quite harsh, continental climate. Its large extent from north to south determines a clearly defined climate zonation and significant differences in climatic conditions in the northern and southern parts of Western Siberia, associated with changes in the amount of solar radiation and the nature of the circulation of air masses, especially the westerly transport flows. The southern provinces of the country, located inland, at a great distance from the oceans, are also characterized by a more continental climate.

During the cold period, two pressure systems interact within the country: areas of relatively high atmospheric pressure, located over the southern part of the plain, an area of ​​​​low pressure, which in the first half of winter stretches in the form of a trough of the Icelandic pressure minimum over the Kara Sea and the northern peninsulas. In winter, continental air masses of temperate latitudes predominate, which come from Eastern Siberia or are formed locally as a result of cooling of the air over the plain.

Cyclones often pass through the border zone of areas of high and low pressure. They recur especially often in the first half of winter. Therefore, the weather in the coastal provinces is very unstable; on the coast of Yamal and the Gydan Peninsula there are strong winds, the speed of which reaches 35-40 m/sec. The temperature here is even slightly higher than in neighboring forest-tundra provinces, located between 66 and 69° N. w. However, further south, winter temperatures gradually rise again. In general, winter is characterized by stable low temperatures; there are few thaws here. Minimum temperatures throughout Western Siberia are almost the same. Even near the southern border of the country, in Barnaul, there are frosts down to?50?52°, i.e. almost the same as in the far north, although the distance between these points is more than 2000 km. Spring is short, dry and relatively cold; April, even in the forest-swamp zone, is not yet quite a spring month.

In the warm season, low pressure sets over the country, and an area of ​​higher pressure forms over the Arctic Ocean. In connection with this summer, weak northern or northeastern winds predominate and the role of westerly air transport noticeably increases. In May there is a rapid increase in temperatures, but often, when arctic air masses invade, there are returns of cold weather and frosts. Most warm month- July, the average temperature of which is from 3.6° on Bely Island to 21-22° in the Pavlodar area. The absolute maximum temperature is from 21° in the north (Bely Island) to 40° in the extreme southern regions (Rubtsovsk). High summer temperatures in the southern half of Western Siberia are explained by the arrival of heated continental air from the south - from Kazakhstan and Central Asia. Autumn comes late. Even in September the weather is warm during the day, but November, even in the south, is already a real winter month with frosts down to -20 -35°.

Most of the precipitation falls in the summer and is brought by air masses coming from the west, from the Atlantic. From May to October, Western Siberia receives up to 70-80% of the annual precipitation. There are especially many of them in July and August, which is explained by intense activity on the Arctic and polar fronts. The amount of winter precipitation is relatively small and ranges from 5 to 20-30 mm/month. In the south in some winter months Sometimes snow doesn't fall at all. Significant fluctuations in the amount of precipitation from year to year are typical. Even in the taiga, where these changes are less than in other zones, precipitation, for example, in Tomsk, falls from 339 mm in a dry year up to 769 mm in wet. Especially large ones are observed in the forest-steppe zone, where, with an average long-term precipitation amount of about 300-350 mm/year in wet years it falls up to 550-600 mm/year, and on dry days - only 170-180 mm/year.

There are also significant zonal differences in evaporation values, which depend on the amount of precipitation, air temperature and the evaporative properties of the underlying surface. The most moisture evaporates in the precipitation-rich southern half of the forest-swamp zone (350-400 mm/year). In the north, in the coastal tundras, where air humidity is relatively high in summer, the amount of evaporation does not exceed 150-200 mm/year. It is approximately the same in the south of the steppe zone (200-250 mm), which is explained by the already low amount of precipitation falling in the steppes. However, evaporation here reaches 650-700 mm Therefore, in some months (especially in May) the amount of evaporated moisture can exceed the amount of precipitation by 2-3 times. The lack of precipitation is compensated in this case by reserves of moisture in the soil accumulated due to autumn rains and melting snow cover.

The extreme southern regions of Western Siberia are characterized by droughts, occurring mainly in May and June. They are observed on average every three to four years during periods with anticyclonic circulation and increased frequency of arctic air intrusions. Dry air coming from the Arctic, when passing over Western Siberia, warms up and is enriched with moisture, but its heating is more intense, so the air moves further and further away from the saturation state. In this regard, evaporation increases, which leads to drought. In some cases, droughts are also caused by the arrival of dry and warm air masses from the south - from Kazakhstan and Central Asia.

In winter, the territory of Western Siberia is covered with snow cover for a long time, the duration of which in the northern regions reaches 240-270 days, and in the south - 160-170 days. Due to the fact that the period of solid precipitation lasts more than six months, and thaws begin no earlier than March, the thickness of the snow cover in the tundra and steppe zones in February is 20-40 cm, in the forest-swamp zone - from 50-60 cm in the west up to 70-100 cm in the eastern Yenisei regions. In treeless - tundra and steppe - provinces, where there are strong winds and snowstorms in winter, the snow is distributed very unevenly, as the winds blow it from elevated relief elements into depressions, where powerful snowdrifts form.

The harsh climate of the northern regions of Western Siberia, where the heat entering the soil is not enough to maintain a positive temperature of the rocks, contributes to soil freezing and widespread permafrost. On the Yamal, Tazovsky and Gydansky peninsulas, permafrost is found everywhere. In these areas of continuous (merged) distribution, the thickness of the frozen layer is very significant (up to 300-600 m), and its temperatures are low (in watershed areas? 4, ? 9°, in valleys? 2, ? 8°). To the south, within the northern taiga to a latitude of approximately 64°, permafrost occurs in the form of isolated islands interspersed with taliks. Its thickness decreases, temperatures rise to -0.5 -1°, and the depth of summer thawing also increases, especially in areas composed of mineral rocks.

Western Siberia is an area stretching 2,500 km from the Arctic Ocean to the dry steppes of Kazakhstan and 1,500 km from the Ural Mountains to the Yenisei. About 80% of the area of ​​Western Siberia is located within the West Siberian Plain, which consists of two flat, bowl-shaped, heavily swampy depressions, separated by Siberian Ridges elevated to 175-200 m. In the southeast, the West Siberian Plain, gradually rising, gives way to the foothills of Altai, Salair, Kuznetsk Alatau and Mountain Shoria. The total area of ​​Western Siberia is 2.4 million km2.

Geology and orography
At the base of the West Siberian Plain lies the West Siberian Plate. In the east it borders on the Siberian platform, in the south - on the Paleozoic structures of Central Kazakhstan, Altai and the Salair-Sayan region, in the west - on the folded system of the Urals. The northern boundary of the plate is unclear; it is covered by the waters of the Kara Sea.

At the base of the West Siberian plate there is a Paleozoic foundation, the depth of which is, on average, 7 km. The most ancient Precambrian and Paleozoic rocks in Western Siberia come to the surface only in the mountainous regions of its southeast, while within the West Siberian Plain they are hidden under a thick cover of sedimentary rocks. The West Siberian Plain is a young plunging platform, the rate and magnitude of subsidence of individual sections of which, and consequently the thickness of the cover of loose sediments, are very different.

The formation of the West Siberian plate began in the Upper Jurassic, when, as a result of breaking off, destruction and degeneration, a huge area between the Urals and the Siberian platform subsided, and a huge sedimentation basin arose. During its development, the West Siberian Plate was repeatedly captured by marine transgressions. At the end of the Lower Oligocene, the sea left the West Siberian plate, and it turned into a huge lacustrine-alluvial plain. In the middle and late Oligocene and Neogene, the northern part of the plate experienced uplift, which gave way to subsidence in Quaternary time. The general course of development of the plate with the subsidence of colossal spaces resembles an incomplete process of oceanization. This feature of the slab is emphasized by the phenomenal development of wetlands.

There remains a lot of unclear and controversial issues about the nature, size and number of ancient glaciations in this territory. It is believed that glaciers occupied the entire northern part of the plain north of 60 o N latitude. Due to the continental climate and small quantity glaciers on the West Siberian Plain were thin, inactive, and did not leave behind powerful moraine accumulations.

Climate
Western Siberia is located at almost the same distance from both the Atlantic Ocean and the center of continentality of Eurasia, so its climate is moderately continental. In winter and summer, when cyclonic activity, and with it the supply of Atlantic air, weakens, Arctic air enters Western Siberia. The deep penetration of Arctic air masses is facilitated by the flatness of the area and its openness to the north.

The average January temperature decreases from -15(C in the southwest to -30(C in the northeast of Western Siberia. The average July temperature increases from +5(C in the north to +20(C in the south). The northeast is characterized by the greatest continentality Western Siberia, where the difference in average temperatures in January and July reaches 45 o.

Hydrography
The rivers of Western Siberia belong to the Kara Sea basin. The largest water artery - the Ob with its tributary Irtysh - is one of the greatest rivers on the globe. The Ob River is formed at the confluence of the Biya and Katun, which originate in Altai, and flows into the Ob Bay of the Kara Sea. Among Russian rivers, it ranks first in terms of basin area and third in terms of water content. In the forest zone, up to the mouth of the Irtysh, the Ob receives its main tributaries: on the right - the rivers Tom, Chulym, Ket, Tym, Vakh; on the left are the Parabel, Vasyugan, Bolshoi Yugan and Irtysh rivers. The largest rivers in the north of Western Siberia - Nadym, Pur and Taz - originate in the Siberian Uvaly.

Geographic zoning
Western Siberia covers five natural zones: tundra, forest-tundra, forest, forest-steppe, steppe, as well as low-mountain and mountain regions of Salair, Altai, Kuznetsk Alatau and Mountain Shoria. Perhaps nowhere on the globe is the zonality of natural phenomena manifested with the same regularity as on the West Siberian Plain.

Tundra , which occupies the northernmost part of the Tyumen region (Yamal and Gydansky peninsulas) and has an area of ​​about 160 thousand km2, has no forests. Lichen and moss tundras of Western Siberia are found in combination with hypnum-grass and lichen-sphagnum, as well as large-hilly bog areas.

Forest-tundra zone extends south of the tundra in a strip of approximately 100-150 km. As a transition zone between tundra and taiga, it is a mosaic combination of areas of open forests, swamps, and bushes. The northern limit of tree vegetation is represented by sparse, crooked larch forests, occupying areas along river valleys.

Forest (taiga, forest-swamp) zone covers the space between 66 o and 56 o N. latitude. a strip of approximately 1000 km. It includes the northern and middle parts of the Tyumen region, the Tomsk region, the northern part of the Omsk and Novosibirsk regions, occupying about 62% of the territory of Western Siberia. Forest zone The West Siberian Plain is divided into subzones of northern, middle, southern taiga and birch-aspen forests. The main type of forests in the zone are dark coniferous forests with a predominance of Siberian spruce, Siberian fir and Siberian pine (cedar). Dark coniferous forests are almost always found in ribbons along river valleys, where they find the necessary drainage conditions. On watersheds they are confined only to hilly, elevated places, and flat areas are occupied mainly by swamps. The most important element of taiga landscapes are swamps of lowland, transitional and upland types. The forest cover of Western Siberia is only 30.5% and is a consequence of weak dissection and associated poor drainage of the entire territory of the region, which contributes to the development of not forest-forming, but swamp-forming processes throughout the entire area of ​​the taiga zone. The West Siberian Plain is characterized by exceptional water content and swampiness; its middle and northern parts are among the most waterlogged areas in the world. earth's surface. The world's largest swamp massifs (Vasyugansky) are located in the southern taiga. Along with the dark coniferous taiga, on the West Siberian Plain there are pine forests, confined to the sandy deposits of ancient alluvial plains and to sandy terraces along river valleys. In addition, within the forest zone, pine is a characteristic tree of sphagnum swamps and forms unique associations of sphagnum pine forests on swampy soils.

Forest-steppe zone , adjacent to the deciduous forest subzone of the forest zone, is characterized by the presence of both forest and steppe plant communities, as well as swamps (ryams), salt marshes and meadows. The woody vegetation of the forest-steppe zone is represented by birch and aspen-birch forests, which occur in islands or in the form of ridges, usually confined to saucer-shaped depressions, while the main background is formed by meadow and forb-grass steppe. Only in the Tobol and Ob regions of this zone are natural island pine forests common. A characteristic feature of the forest-steppe of Western Siberia is the grivna-hollow topography and the abundance of salty drainless lakes.

Steppe zone covers southern part Omsk and southwestern parts of the Novosibirsk regions, as well as the western part Altai Territory. It includes the Kulundinskaya, Aleiskaya and Biyskaya steppes. Within the zone, ribbon pine forests grow along ancient hollows of glacial water flow.

The significant height of the mountains of Western Siberia determines the development of altitudinal zones here. In the vegetation cover of the mountains of Western Siberia, the leading position is occupied by forests, covering most of the area of ​​the Salair Ridge and Kuznetsk Alatau and about 50% of the territory of Altai. The high-mountain belt is clearly developed only in the Altai mountains. The forests of Salair, Kuznetsk Alatau, the northeastern and western parts of Altai are characterized by the widespread development of relict taiga formations, which are found only in the mountains of southern Siberia. Among the black taiga in the Kondoma River basin there is a relict “linden island” - an area of ​​linden forest with an area of ​​about 150 km2, considered as a remnant of tertiary vegetation.

Biodiversity
Higher vascular plants are characterized by the least diversity in all zonal areas of Western Siberia. On average, the flora of Western Siberia is approximately 1.5 times poorer compared to adjacent regions; the gap is especially large for the taiga and tundra zones. The fauna of Western Siberia is characterized by higher relative diversity. Thus, in the four main orders of mammals in Western Siberia there are 80 species, for Eastern Siberia and European Russia - 94 and 90, respectively. Species common to Eastern Siberia - 13, with European Russia - 16, common to all three regions - 51; those found only in Western Siberia - no. The bird fauna is most diverse, the majority of species in Western Siberia are migratory. In terms of the total number of bird species, Western Siberia is not significantly inferior to adjacent regions in any zonal area, and surpasses them in waterfowl and semi-aquatic species.

The main reason for the poverty of the flora and fauna of Western Siberia is most often considered to be the consequences of the Pleistocene glaciation, which was the most devastating on its territory, as well as the remoteness of mountain refugia that fed the migration flow in the Holocene.

Administrative division
On the territory of Western Siberia there are Tyumen, Tomsk, Omsk, Novosibirsk, Kemerovo regions, as well as parts of the Kurgan, Chelyabinsk and Sverdlovsk regions and the Altai and Krasnoyarsk territories. Most Big City Western Siberia - Novosibirsk (1.5 million inhabitants) is located on the Ob River.

Economic use(mining, forestry)
The most developed industries in Western Siberia are mining (oil, gas, coal) and forestry. Currently, Western Siberia produces over 70% of all-Russian oil production and natural gas, about 30% of coal production, about 20% of timber harvested in the country.

A powerful oil and gas production complex currently operates in Western Siberia. The largest deposits of oil and natural gas are associated with the thick layer of sedimentary rocks of the West Siberian Plain. The area of ​​oil and gas bearing lands is about 2 million km2. Forest-swamp landscapes, completely untouched by industrial development and practically unexplored until the 60s, are dissected for hundreds of kilometers by pipelines, roads, power lines, dotted with drilling sites, oiled with oil and petroleum product spills, covered with burns and soaked forests resulting from the use of outdated technologies for oil and gas production and transportation.

It should be taken into account that Western Siberia, like no other region in the world, abounds in rivers, lakes and swamps. They contribute to the active migration of chemical pollutants entering the Ob River from numerous sources, which carries them into the Gulf of Ob and further into the Arctic Ocean, endangering the destruction of ecosystems remote from the areas of the oil and gas complex.

In contrast to the West Siberian Plain, the Kuznetsk mountain region is distinguished by its reserves of hard coal: the Kuznetsk coal basin accounts for 40% of the country's industrial coal reserves. The main production centers are the cities of Leninsk-Kuznetsky and Prokopyevsk.

Prepared by E.A. Chelaznova