Characteristics of the Laptev Sea PTC. Laptev Sea: description and characteristics, islands and map, flowing rivers. Bottom relief of the Laptev Sea
The Laptev Sea is a peripheral or marginal sea of the Arctic Ocean, which is located near the northern coast of Russia, in Asia. In the west it is limited by the Taimyr Peninsula and the Severnaya Zemlya Islands, in the east by the New Siberian Islands.
The neighboring sea is the Kara Sea, with which the Laptev Sea is connected by the Vilkitsky Strait, as well as the East Siberian Sea, with which it is connected by the Sannikov and Dmitry Laptev Straits. The Laptev Sea is named after the Russian navigators and explorers of the north Khariton and Dmitry Laptev, who explored this harsh territory back in the 18th century. In the language of the indigenous people, the Yakuts, the name sounds like Laptevtar. One of the previous names is Nordenskiöld.
Sea area - 672 thousand. km.sq.
The prevailing depths are 30 – 80 m.
Average depth – 540 m.
The greatest depth is 3385 m.
Geographic coordinates: 76°16’07”N. 125°38’23”E
The salinity of the water is low.
The coastline has a length of 1300 km and is quite indented. Because of this, there are many bays and bays on the coast. Main bays: Olenksky, Khatanga, Thaddeya.
The climate here is Arctic continental and very harsh. Temperatures remain below zero degrees Celsius for more than nine months of the year. And only for two months, August and September, the sea is freed from the ice that binds it. Water temperature in summer in the south is from +12 to +15°, in the north from +1 to +6°. In winter, the water temperature under the ice: -1.5°C. The polar night and day last more than three months each. The air temperature in January reaches -50°C, and in July it rarely reaches +5°C
The density of the indigenous population (Yukaghirs, Chuvans, Evenks and Evens) is very low. Their traditional activities are reindeer herding, fishing, and hunting. And this despite the fact that the local flora and fauna are very scarce. In the Laptev Sea there are 39 species of fish, the main ones being char, omul, whitefish, sturgeon, vendace, nelma and sea animals - seal, walrus, beluga. On the islands and coast - polar bear, arctic fox.
On the territory of the sea there are a couple of dozen islands on which the remains of mammoths were found, which were preserved in good condition. The largest port village is Tiksi.
The following rivers flow into the Laptev Sea: Lena, Anabar, Khatanga, Olenk, Yana and other smaller rivers.
Today, the main human activity in this region is navigation and mining.
Video: Tiksi. Laptev sea.
Group “Lips” - Laptev Sea (Reggae with Adriano Celentano. Comedy Club
This sea is limited by natural boundaries and conventional lines. Sea waters are well connected with. This sea has the status of a continental marginal sea.
There are about several dozen islands in the waters of the Laptev Sea. Most of them are located in the western zone of the sea. Here the islands are located both in small groups and individually. Here are the following groups skeletons: Komsomolskaya Pravda, Vilkitsky and Thaddeus. Among the single skeletons, the largest are: Starokadomsky, Maly Taimyr, Bolshoy Begichev, Peschany, Stolbovoy and Belkovsky. A large number of small islands are located in river deltas.
The coastline of the sea is quite uneven; there are a large number of bays, bays, and capes. The eastern shores of the Severnaya Zemlya islands and the Taimyr Peninsula are heavily indented. To the east of it there are large bays: Khatanga, Anabarsky, Oleneksky and Yansky. There are also bays (Kozhevnikova, Nordvik, Tiksi), bays (Vankina and Buor-Khaya) and peninsulas (Khara-Tumus, Nordvik). The shores washed by the Laptev Sea have different... Some shores have low mountains, some are lowlands.
The Laptev Sea is located in the shelf zone, the continental slope, and occupies a small area of the ocean floor. Due to this location, it ends abruptly in the north. On this plain there are several hills and banks. There is a short trench opposite the mouth. A narrow and fairly long trench extends from Stolbovoy Island to the north. Another trench is located near Oleneksky Bay. In the east of the Laptev Sea there are two banks, Semenovskaya and Vasilievskaya.
Most of the sea is shallow. The shallowest part is located in the south of the sea. Half of the sea has a depth of up to 50 m. When moving north, the depth of the sea increases. First there are minor changes in depth (from 50 m to 100), and then the depth increases sharply from 2000 m or more.
Climatic conditions The Laptev Seas are quite harsh compared to other seas. This is due to the location of the sea near, the distance from the waters and the neighboring location of the mainland. The climatic conditions of the sea are close to continental ones. Although there are also features of the sea. In the Laptev Sea, such a continental climate feature can be traced as a strong change in air temperature throughout the year. But under the influence of the sea this fluctuation is not as clearly expressed as on land.
IN different time different centers influence the climate of the sea each year. During the cold period, the sea is predominantly dominated by a high area. In autumn, the winds of alternating direction give way to southern ones, and their strength increases to gale force.
In winter, three zones can be distinguished at sea, which have slightly different climatic conditions. The southeastern part of the sea is dominated by the Siberian Sea. In the north, the influence of the Polar Maximum is felt. West Side is periodically influenced by the Icelandic low. The Siberian Anticyclone has the greatest impact on the expanses of the Laptev Sea. Thus, in winter, southern and southwestern winds blow predominantly, the speed of which is about 8 m/s. At the end of winter, their strength weakens and calms are observed. During this period, a strong cooling is noticeable. in January it drops to – 26 – 29°C. In general, the weather in winter is cloudless and calm. Sometimes formed south of the sea, contribute to the emergence of powerful northern ones. Such storms continue for several days and then cease.
During the warm period, the area of high pressure is replaced by a trough of low pressure. Spring winds do not have a constant direction. Along with the southern winds, there are also northern ones. Such winds are usually gusty and not strong. The air temperature is constantly increasing. But the weather is still quite cold. In summer, northern winds prevail, the speed of which does not exceed 3 - 4 m/s. Powerful winds are not typical for summer. At this time it rises and reaches its highest point in August +1-5°C. In enclosed spaces, the air temperature can be significantly higher. For example, in Tiksi Bay the temperature was recorded at +32.5°C. Summer is very often dominated by cyclones, making it cloudy and rainy.
Fishing and hunting of sea animals is poorly developed; marine fishing is mainly carried out near river mouths. The Laptev Sea is of economic importance as transport operations take place here. The port of Tisci is of great importance in the departure and delivery of goods.
The coastal waters of the Laptev Sea contain a high concentration of phenol, which comes along with the waters. The high content of phenol in river and coastal waters is due to the huge number of sunken trees. The most polluted waters are the Neelov Bay. The water spaces of Tiksi and Buor-Khaya bays are polluted. The ecological situation of Bulunkan Bay is noted as catastrophic. The content of large amounts of toxic substances in coastal waters is due to the discharge of untreated water from Tiksi. The sea also contains a large amount of petroleum products in areas of developed shipping.
Between the Severnaya Zemlya archipelago and the Taimyr Peninsula in the west and the New Siberian Islands in the east lies the sea, which bears the name of the Russian navigators the Laptev brothers. Its western border runs along the eastern shores of the Severnaya Zemlya islands from Cape Arktichesky (Komsomolets Island), through the Strait of the Red Army along the eastern shore of the island. October Revolution to cape Anuchina, through the Shokalsky Strait to cape Peschany on the island. Bolshevik and along its eastern shore to Cape Vaygach, then along the eastern border of the Vilkitsky Strait and further along the mainland shore to the top of Khatanga Bay. The northern border of the sea runs from Cape Arkticheskiy to the point of intersection of the meridian of the northern tip of the island. Kotelny (Cape Anisiy) with the edge of the continental shallows (79° N, 139° E), the eastern border is from this point along the meridian to the island. Kotelny, further along its western shore, through the Sannikov Strait, along the western shores of the Bolshoi and Maly Lyakhovsky islands and along the western border of the Dmitry Laptev Strait to Cape Svyatoy Nos. The southern border of the sea runs along the mainland coast from this cape to the top of Khatanga Bay.
The Laptev Sea is a type of continental marginal sea. Its area is 662 thousand km 2, its volume is 353 thousand km 3, its average depth is 533 m, its greatest depth is 3385 m.
There are several dozen islands in the Laptev Sea, most of which are located in the western part of the sea. The largest islands are Komsomolskaya Pravda, Vilkitsky and Thaddeus. Among the single islands, the islands of Starokadomsky, Maly Taimyr, Bolshoy Begichev, Peschany, Stolbovoy and Belkovsky stand out for their size. Many small islands are located in river deltas.
The seashores are quite indented and form bays, lips, bays, peninsulas and capes of various shapes and sizes. The eastern shores of the Severnaya Zemlya islands and the Taimyr Peninsula are significantly dismembered. East of it coastline forms several large bays (Khatansky, Anabarsky, Oleneksky, Yansky), bays (Kozhevnikova, Nordvik, Tiksi), lips (Buor-Khaya, Vankina) and peninsulas (Khara-Tumus, Nordvik). The western coast of the New Siberian Islands is much less indented.
The nature of the seashores is quite diverse. There are both abrasive and accumulative ones, and there are also icy shores. Sometimes low mountains approach the water; most of the coast is low-lying.
Climate
The Laptev Sea is one of the harshest Arctic seas. Its climate, generally maritime polar, also has signs of continentality, which is most clearly manifested in relatively large annual fluctuations in air temperature.
In the cold season, the sea is located mainly in the area of high atmospheric pressure - the Siberian anticyclone. In autumn, unstable winds gradually become south direction and intensify to storm conditions. Cyclones pass less frequently and cloud cover decreases.
In winter, the Laptev Sea is affected by three large pressure systems. Above the southeastern part lies a spur of the Siberian anticyclone, the center of which is located near the Yana Bay. The ridge of the polar maximum extends from the north. In the western part of the sea, the influence of the Icelandic low is sometimes observed. In accordance with such pressure conditions, southern and southwestern winds with an average speed of about 8 m/s predominate this season. Towards the end of winter, their speed decreases, and calms are often observed. The air is becoming very cold. The air temperature over the sea generally decreases from northwest to southeast in January and in the Tiksi Bay area is -26 - 29°. Calm and partly cloudy winter weather sometimes interrupted by cyclones passing slightly south of the sea. They cause severe cold north winds and snowstorms that last only a few days.
At the beginning of the warm season, the destruction of atmospheric pressure areas begins. The pressure environment is generally similar to the winter one, but somewhat more diffuse, so the spring winds are very unstable in direction. In addition to the southern ones, sometimes northern winds also blow. Usually the winds are gusty, but not strong. The air temperature is steadily rising. Cloudy and rather cold weather prevails. In summer, the Siberian maximum is absent, and the polar maximum appears rather faintly. To the south of the sea the pressure is slightly reduced, above the sea itself it is slightly increased. As a result, northern winds most often blow at a speed of 3-4 m/s. Strong winds (with speeds greater than 20 m/s) are not observed in summer. Average monthly temperature air in August is the highest of the year; in the central part of the sea the temperature is 1-5°. On the coast in closed bays, the air sometimes (though very rarely) warms up quite significantly (up to 32.7° in Tiksi). Summer is characterized by increased cyclonic activity. At this time over southern part There are cyclones in the seas, which fill up here. Then cloudy weather with continuously drizzling rain sets in over the sea. At the end of August, the Siberian maximum pressure begins to form, which marks the transition to autumn.
Thus, the Laptev Sea is under the influence of the Siberian anticyclone for most of the year. This causes relatively weak cyclonic activity and predominantly weak winds of a monsoon nature.
Long-term and strong cooling with a calm wind regime in winter is the most important climatic feature of the sea. Another very important factor in the formation of the natural appearance of the Laptev Sea is continental runoff. Many small and several large rivers flow into this sea. The largest of them - Lena - annually brings on average about 515 km 3 of water, Khatanga - over 100, Yana - more than 30, Olenek - about 35 and Anabar - about 20 km 3. All other rivers provide about 20 km 3 of water per year. The total annual flow into the sea is approximately 720 km 3, which is 30% of the total flow into all Arctic seas. However, the distribution of runoff is very uneven in time and space. About 90% of the annual flow occurs in the summer months (June-September), of which about 35 - 40% of the annual flow falls in August, while in January it barely reaches 5%. This nature of the flow distribution throughout the year is explained by the fact that the rivers flowing into the Laptev Sea are fed by snow, and the overwhelming majority of their waters flow into the southeastern part of the sea (Lena alone provides 70% of the total coastal runoff). Depending on the amount of water brought by the rivers and the hydrometeorological situation, river waters spread either to the northeast, reaching the northern tip of the island. Kotelny, then far to the east, going through the straits into the East Siberian Sea. Large continental runoff leads to desalination of water over vast areas of the sea, especially in its southern and eastern parts.
Water temperature and salinity
The Laptev Sea (like the Kara Sea) is dominated by Arctic surface waters. In zones of strong influence of coastal runoff, as a result of the mixing of river and surface Arctic waters, water with a relatively high temperature and low salinity is formed. At their interface (5-7 m horizon) large gradients of salinity and density are created. In the north, in a deep trench, warm Atlantic waters are distributed above the surface Arctic water, but their temperature is somewhat lower than in the trenches of the Kara Sea. They penetrate here 2.5 - 3 years after they begin their journey near Spitsbergen. In the deeper (compared to the Kara) Laptev Sea, the horizons from 800-1000 m to the bottom are occupied by cold bottom Arctic water with a temperature of –0.4-0.9° and almost uniform (34.90-34.95‰) salinity.
For most of the year, water temperatures are close to freezing and drop quickly after the summer high. In winter, the surface water temperature varies from –0.8° (near Mostakh Island) to –1.7° (near Cape Chelyuskin), which is due to differences in salinity in these areas.
In the first spring months, the ice melts, so the water temperature remains almost the same as in winter. Only in coastal areas (especially in estuary areas), which are cleared of ice earlier than others, the water temperature is slightly higher than in central regions. It generally decreases from south to north and from east to west. During the summer, the sea surface warms up noticeably. In August in the south (Buor-Khaya Bay) the water temperature on the surface can reach 10 and even 14°; in the central regions it is 3–5°; at the northern tip of the island. Kotelny 0.8° and at metro Chelyuskin 1°. In general, the western part of the sea, where the cold waters of the Arctic basin arrive, is characterized by a lower (2 - 3°) water temperature than the eastern part, where the bulk of warm river waters is concentrated, and the surface temperature here can reach 6 - 8°.
The water temperature decreases quickly with depth. In winter, in areas with depths of up to 50 - 60 m, the water temperature is the same from surface to bottom. In the coastal zone it is –1-1.2°, and in the open sea about –1.6°. In the northern regions, at horizons of 50-60 m, the water temperature rises by 0.1-0.2° due to the influx of other waters.
In the north, in the area of the deep trench, negative temperature observed from the surface to 100 m. Below it begins to rise (to 0.6-0.8°) to approximately 300 m and then slowly decreases towards the bottom. High temperature values (above zero) in the 100-300 m layer are associated with the penetration of warm Atlantic waters from the Central Arctic Basin into the Laptev Sea.
In summer upper layer 10-15 m thick, it warms up well and has a temperature of 8-10° in the southeastern part and 3-4° in the central regions. Deeper than these horizons, the temperature drops sharply and reaches –1.4-1.5° at a horizon of 25 m. These values or values close to them are maintained until the very bottom. In the western part of the sea, where the heating is less, such sharp differences in temperature are not observed.
Salinity in the Laptev Sea is very heterogeneous: in summer it varies from 1 to almost 31‰, but in the surface layer desalinated waters with a salinity of 20-30‰ predominate, and its distribution is very complex. In general, it increases from southeast to northwest and north.
In winter, with minimal river flow and intense ice formation, salinity increases. At the same time (as in summer) in the west it is higher (at Cape Chelyuskin - 34‰) than in the east (at Kotelny Island - 25‰). This high salinity lasts for quite a long time, only in June with the beginning of the melting of the ice does it begin to decrease .
In summer, the southeastern part of the sea is the most desalinated. In Buor-Khaya Bay, salinity drops to 5‰ and below, to the west of the Lyakhovsky Islands it increases (10-15‰). In the west of the sea, saltier waters spread (30 - 32‰). They are located slightly north of the island line. Petra - m. Anisiy. Thus, desalinated waters flow to the north in the eastern part of the sea, and salty waters flow down to the south in the western part of the sea.
Salinity increases with depth, but there are seasonal differences in its distribution. In winter, in shallow water, it increases from the surface to horizons of 10 - 15 m, and below and to the bottom it remains almost unchanged. At great depths, salinity increases noticeably not from the surface itself, but from the underlying horizons. The spring vertical distribution of salinity begins with the intensive melting of snow and ice. At this time, salinity quickly decreases in the surface layer and retains winter values in the lower horizons.
In summer, in the zone of distribution of river waters, the upper layer (5 - 10 m) is very strongly desalinated; below, a very sharp increase in salinity is observed. In the layer from 10 to 25 m, the salinity gradient in some places reaches 20‰ per 1 m. In the northern part of the sea, salinity increases relatively quickly from the surface to 50 m, from here to 300 m salinity increases more slowly (ranging from 29 to 33 - 34‰) , deeper it almost does not change.
In autumn, in the southern regions, the summer jump in salinity is gradually eroded.
In the Laptev Sea, the density distribution is more related to salinity than to temperature. This is explained by the wide range of salinity and the weak effect of low water temperature on density.
Density increases from southeast to northwest. In winter and autumn, the water is denser than in summer and spring. In winter and early spring, the density is almost the same from surface to bottom. In summer, large gradients of salinity and temperature on horizons of 10-15 m also determine a sharp drop in density. In autumn, due to cooling and salinization of surface waters, their density increases.
Density stratification of waters is clearly visible from late spring to early autumn. It is most pronounced in the southeastern and central regions of the sea and at the edge of the ice.
Port in the Arctic
Bottom relief
The bottom of the Laptev Sea is an almost undivided plain, gently sloping to the north. There are several gutters, low hills and banks. A wide but short trench is located against the Lena delta, a funnel-shaped trench is located near Oleneksky Bay, a narrow and long trench goes away from the island. Stolbovoy to the north. In the eastern part of the sea the Semenovskaya and Vasilievskaya banks rise. Half of the entire sea area is occupied by depths of up to 50 m, and to the south 76° N. latitude. they do not exceed 25 m. The northern part of the sea is much deeper. At a depth of 100 m, the bottom drops sharply. The appearance of the sea is formed mainly by the waters of the southern part with depths of 25-100 m.
Bottom topography and currents of the Laptev Sea
Currents
Wind mixing in ice-free areas of the sea is poorly developed due to relatively weak winds in the warm season and high sea ice cover. During spring and summer, the wind mixes only the uppermost layers up to 5-7 m thick in the east and up to 10 m in the western part of the sea.
Strong autumn-winter cooling and intense ice formation cause active development convective mixing. Due to the relatively high degree of water homogeneity and early ice formation, density mixing penetrates most deeply (to horizons of 90-100 m) in the north of the sea. In the central part, convection reaches the bottom (40-50 m) by the beginning of winter, and in the southern part, due to large vertical salinity gradients, even at small (up to 25 m) depths, it spreads to the bottom only at the end of winter.
In general, the sea is characterized by the usual cyclonic circulation. The coastal flow, moving along the coast of the continent from west to east, deviates to the north and northwest at the eastern shores and, in the form of the Novosibirsk Current, goes beyond the sea, connecting with the Trans-Arctic Current of the Central Arctic Basin. From it, at the northern tip of Severnaya Zemlya, the East Taimyr Current branches off to the south, which moves south along the eastern shores of Severnaya Zemlya and the Taimyr Peninsula and closes the cyclonic ring. A small part of the waters of the coastal stream flows through the Dmitry Laptev and Sannikov straits into the East Siberian Sea.
Current velocities in this gyre are low (2 cm/s). Depending on the large-scale pressure situation, the center of cyclonic circulation may shift from the middle of the northern part of the sea towards Severnaya Zemlya. Accordingly, branches arise from the main flows. Tidal currents are superimposed on the constant currents.
In the Laptev Sea, the tides are well defined and have an irregular semidiurnal pattern everywhere. The tidal wave enters from the north from the Central Arctic Basin, attenuating and deforming as it moves south. The magnitude of the tide is usually small, mostly about 0.5 m. Only in the Khatanga Bay the range of tidal level fluctuations exceeds 2 m at syzygy. This is explained by the well-known “funnel” effect observed, for example, in the Bay of Fundy. The tidal wave that arrived in the Khatanga Bay (“funnel”) grows in size and spreads almost 500 km up the river. Khatanga. This is one of the cases of deep penetration of a tidal wave up the river. However, boron phenomena are not observed in Khatanga. In other rivers flowing into the Laptev Sea, the tide almost never enters. It fades very close to the mouths, since the tidal wave is extinguished in the deltas of these rivers.
In addition to tidal fluctuations, seasonal and surge level fluctuations are observed in the Laptev Sea. Seasonal changes in levels are generally insignificant. They are most pronounced in the south-eastern part of the sea, in areas close to river mouths, where the range of fluctuations reaches 40 cm. The minimum level is observed in winter, the maximum in summer.
Surge level fluctuations are observed everywhere and at any time of the year, but they are most significant in the southeastern part. Surges and surges cause the largest decreases and increases in the level in the Laptev Sea. The range of fluctuations in the surge level reaches 1-2 m, and sometimes reaches 2.5 m (Tiksi Bay). Most often, surges and surges are observed in the fall with strong and stable winds. In general, northern winds cause surge, and southern winds cause surge, but depending on the configuration of the coasts, surge-level fluctuations in each specific area create winds in certain directions. Thus, in the southeastern part of the sea, the most effective surge winds are western and northwestern.
On average, the Laptev Sea is dominated by waves of 2-4 points with wave heights of about 1 m. In summer (July - August) storms of 5-7 points occasionally develop in the western and central parts of the sea, during which wave heights reach 4-5 m. Autumn - the stormiest time of the year, when the maximum number of high waves(up to 6 m). However, even in this season, waves with a height of about 4 m predominate, which is determined by the acceleration length and depths.
Ice cover
Most of the year (from October to May) the Laptev Sea is covered with ice. Ice formation begins at the end of September and occurs simultaneously throughout the entire sea. In winter, in its shallow eastern part, extensive fast ice up to 2 m thick is developed. The limit of the distribution of fast ice is a depth of approximately 25 m, which in this area of the sea is several hundred kilometers away from the coast. The area of fast ice is approximately 30% of the area of the entire sea. In the western and northwestern parts of the sea, fast ice is small, and in some winters it is completely absent. To the north of the fast ice zone there are drifting ice.
With the almost constant removal of ice from the sea to the north in winter behind the fast ice, significant areas of polynyas and young ice. The width of this zone varies from tens to several hundred kilometers. Its individual sections are called the East Severozemelskaya, Taimyr, Lena and Novosibirsk polynyas. The last two reach enormous sizes (thousands of km2) at the beginning of the warm season. Ice melting begins in June - July, and by August large areas of the sea are free of ice. In summer, the ice edge often changes its position under the influence of winds and currents. The western part of the sea is generally more icy than the eastern. From the north along the eastern coast of Taimyr, the oceanic Taimyr ice massif descends into the sea, in which heavy multi-year ice is often found. It persists steadily until new ice formation, moving either north or south depending on the prevailing winds. The local Yana ice massif, formed by fast ice, usually melts “in place” by the second half of August or is partially carried north out of the sea.
Economic importance
Due to severe natural conditions The biological productivity of the Laptev Sea is low, and life in its waters is generally poor in quantity and quality. 37 species of fish live here. Vendace, omul, and partly muksun are caught in very small quantities.
The Laptev Sea is one of the marginal seas of the Arctic Ocean. It stretches between the Taimyr Peninsula, the Severnaya Zemlya Islands and the New Siberian Islands. The sea area has an area of about 672 thousand square meters. km. The maximum depth is almost 3390 m, and the average depth is 540 m. This sea got its name thanks to Russian explorers and navigators - Dmitry and Khariton Laptev. They carried out explorations of the North Sea back in the 18th century. The Yakuts (indigenous people) call this body of water “Laptevtar”.
Features of the sea
A map of the Laptev Sea shows that its shores are heavily indented. The sea has large bays: Khatanga, Anabarsky, Yansky, Oleneksky, etc. There are many islands in its vast water area. They are concentrated mainly in its western part. The largest island groups: Thaddeus, Vilkitsky and Komsomolskaya Pravda. Single islands include Maly Taimyr, Peschany, Bolshoi Begichev, Starokadomskogo, etc.
The rugged coast of the Laptev Sea forms a variety of peninsulas, lips, capes, bays and bays. The following rivers carry their waters into this sea: Yana, Anabar, Khatanga, Olenek and Lena. They form vast deltas where they flow into the sea. The salinity of sea water is low.
Climatic conditions
The Laptev Sea is considered the harshest among the Arctic seas. The climate there is close to continental, but has pronounced polar and marine features. Continentality is expressed in significant fluctuations in annual temperature. The climate in different areas of the sea is heterogeneous. In autumn, winds form over the sea, which easily intensify into storms. In winter it is calm and partly cloudy. Rare cyclones occur, causing cold and strong winds.
Use of the Laptev Sea
The sea is located far from the center of the country, in a harsh climate. Therefore, its economic use is difficult. The Laptev Sea is of great importance for the Russian economy, since cargo is transported in this area along the northern sea route. Here the transit of goods takes place and their delivery to the port of Tiksi. Locals are engaged in fishing. The density of indigenous people is very low. Evenks, Yukaghirs and other nationalities live on the banks. The Laptev Sea is the site of various scientific research. Scientists study how water circulates, monitor ice balance, and make hydrometeorological forecasts.
LAPTEV SEA, a marginal sea of the Arctic Ocean, off the northeastern coast of Asia, between the Severnaya Zemlya archipelago, the Taimyr Peninsula, the coast of Siberia and the New Siberian Islands. It communicates through the straits with the seas: in the west with the Kara, in the east with the East Siberian. The western border runs from Cape Arktichesky (the northern point of Komsomolets Island) along the eastern shores of the islands of the Severnaya Zemlya archipelago and the Red Army, Shokalsky, Vilkitsky straits, then along east coasts Taimyr Peninsula to the mouth of Khatanga; southern - further along the mainland coast to Cape Svyatoy Nos (141° east longitude); eastern - along the Dmitry Laptev Strait, the western shore of the Bolshoi Lyakhovsky Island, the Eterikan Strait, the western shore of the Maly Lyakhovsky Island, the Sannikov Strait, west coast Kotelny Island to Cape Anisiy, then in the open sea along the meridian of 139° east longitude to the parallel of 79° north latitude; northern - from this point along the arc of a great circle to Cape Arctic. Within these boundaries, the area of the Laptev Sea is 662 thousand km 2, the volume is 353 thousand km 3. The greatest depth is 3385 m (79°35'N, 124°40'E).
The heavily indented shores of the Laptev Sea form many bays, bays, and peninsulas. Large bays - Khatanga, Anabarsky, Olenyoksky, Yansky, Faddeya; bays - Pronchishchevoy, Kozhevnikova, Nordvik, Tiksi; lips - Buor-Khaya, Vankina, Sellyakhskaya, Ebelyakhskaya; peninsulas - Khara-Tumus, Nordvik, Shirokostan. There are several dozen islands (mostly small ones) located off the western and southern coast; the largest islands are Bolshoy Begichev, Maly Taimyr, Starokadomskogo, Belkovsky, Stolbovoy; groups of islands - Thaddeus, Komsomolskaya Pravda, Petra, Danube. Many small islands are located in the mouths and deltas of rivers. The nature of the coasts is varied, abrasion and accumulative predominate; large sections of the coasts are composed of fossil ice and are subject to intense erosion; Thus, the islands of Vasilievsky and Semenovsky, discovered in 1815, were completely washed away and by the mid-1950s they turned into sand banks with the same names. Coasts for the most part low-lying, but in some areas low mountains come close to the coastline.
Relief and geological structure bottom. The bottom of the Laptev Sea is represented by a plain weakly dissected by several troughs, gently sloping from south to north. The sea is shallow, about half of the bottom is at depths less than 50 m, the shelf (along the isobath of 200 m) occupies 72%. The continental slope is cut through by the deep-sea Sadko Trench, which to the north turns into the Nansen Basin. Areas with depths of more than 2000 m (northwestern part of the sea) account for only 13%. The large, shallow part of the Laptev Sea is located in the area of the junction of the Taimyr, Verkhoyansk-Kolyma and Novosibirsk-Chukchi fold systems, the Mesozoic complexes of which are dissected by a branched Cenozoic rift system of northwest strike and covered by a cover of Upper Cretaceous - Cenozoic sediments with a thickness of 1-1.5 km per uplifts up to 8-12 km in troughs. In the northern, deep-sea part of the sea, the sedimentary cover rests on igneous rocks of the oceanic crust. Modern bottom sediments on the shelf are represented by sands, silty silts, sometimes with inclusions of pebbles and boulders; in deep-sea areas, predominantly silty-clayey and clayey silts are observed at the bottom. Sedimentation in coastal areas is significantly influenced by solid river runoff. Lena and Yana alone annually bring up to 17.5 million tons of suspended sediment to the southeastern part of the sea. The eastern part of the Laptev Sea is seismically active (earthquakes with a magnitude of up to 6 occur); increased seismicity of the coast is noted.
Climate. The climate is Arctic marine, with features of continental in the southern coastal areas; high-latitude position, proximity to the mainland, isolation from the moderating influence of the Atlantic and Pacific Oceans determine its severity. polar night lasts from three to five months. For most of the year, the sea is under the influence of the Siberian High, which causes weak cyclonic activity and the monsoon nature of the wind situation. In winter, southern and southwestern winds prevail at a speed of 8-10 m/s, the air becomes very cold, the temperature in January drops to -34 °C, the absolute minimum was -61 °C. In summer, predominantly northern winds (speed 3-4 m/s), air temperature in July from 0 ° C at the northern borders to 4 ° C at southern coasts. In small bays well protected from the wind, the air warms up to 12-15 °C in summer, maximum temperatures in summer reach 22-24 °C, minimum temperatures drop to -4 °C.
Hydrological regime. Many small and several large rivers flow into the Laptev Sea, so fresh runoff has a noticeable impact on the hydrological regime of the shallow sea. One of the largest rivers in the Arctic Ocean basin, the Lena annually brings 520 km 3 of water, Khatanga - 105 km 3, Olenyok - 38 km 3, Yana - 31.5 km 3. In total, over 700 km 3 enters the Laptev Sea annually fresh water, or over 30% of the river flow of the Arctic basin. The flow is unevenly distributed across the seasons: in January, about 36 km 3 (over 5% of the annual value) flows into the sea, and in August up to 290 km 3 (over 40%) of water flows into the sea. In coastal areas with a strong influence of river runoff, highly desalinated water is formed in the surface layer in summer, when in the Lena estuary the salinity drops to 10‰. Salinity increases towards the north and northwest, reaching 31‰ at the Arctic Cape. The surface water temperature at this time varies from 4 to -1 °C. In winter, salinity everywhere increases noticeably due to a decrease in fresh runoff and salinization of the surface layer during the process of ice formation: in the Tiksi area up to 15‰, near the Arctic Cape up to 33‰. The surface water temperature in winter is everywhere close to the freezing point and is determined by the salinity of the water, varying accordingly from -1 to -1.8 °C. With depth, the temperature quickly decreases and deeper than 15-20 m, even in summer it takes negative values everywhere. Only in deep-sea areas, in a layer of 100-300 m, is the water temperature above 0 ° C due to the warming influence of intermediate Atlantic waters.
Most of the year the sea is covered with ice. The ice-forming season lasts from 7-8 months in the south to 9-11 months in the north. In cold years, ice can form in all seasons, very warm years at the end of August - beginning of September the sea is completely free of ice. Vast coastal areas, especially in the southeastern part, are covered with stationary fast ice in winter.
Typically, the width of the fast ice strip is determined by an isobath of 25 m, so in the Laptev Sea fast ice can occupy up to 30% of the water area. On the rest of the sea the ice is drifting. By the end of winter, fast ice and drifting ice can (in one season) grow in thickness up to 1.8-2.0 m. The concentration of drifting ice strongly depends on the prevailing winds. Steady easterly winds often drive away drifting ice from the fast ice, creating a space of open water even in the most severe frosts - the so-called fast ice polynya. This phenomenon in the past was called the Great Siberian Polynya. With the cessation of the eastern winds, the polynya is quickly covered with young ice.
Due to weak winds in summer and high ice concentration in winter, wind mixing is poorly developed and usually does not penetrate deeper than 8-10 m. Autumn-winter cooling and ice formation contribute to the development of convective mixing, which in shallow southern areas penetrates to the bottom by the end of winter, and in northern ones - to a depth of 90-100 m. The horizontal circulation is mainly cyclonic in nature. Along the mainland coast the flow moves from west to east. Near the New Siberian Islands, most of the flow goes north in the form of the Novosibirsk Current, where it splits into two branches: one turns east, into the East Siberian Sea, the other goes west. Near Severnaya Zemlya, the current deviates to the south and, under the name of the East Taimyr Current, closes the cycle.
The tides are of an irregular semi-diurnal nature, the height is 0.3-0.8 m. Only at the top of the funnel of the Khatanga Bay during syzygy does the tide exceed 2 m. Up the Khatanga tidal wave penetrates 200-300 km. Surge level fluctuations usually do not exceed 2.0-2.5 m. Seasonal level fluctuations are small, observed mainly only in the south-eastern regions, where they reach 0.4 m (the minimum level is observed in winter, the maximum in summer). The prevailing waves are 2-4 points with a wave height of about 1 m. In the central part of the sea, during autumn storms with a force of 5-7 points, the wave height reaches 4-5 m, their maximum height is 6 m.
History of the study. The Laptev Sea has been known to Russian explorers since the 1st half of the 17th century. Traces of a Pomeranian artel found on the shores of the Taimyr Peninsula indicate that the Russians entered the Laptev Sea no later than 1620. In 1633-34, explorers Ilya Perfilyev and I.I. Rebrov, going down the Lena, discovered Olenyok Bay, the mouth of the Olenyok River, Yansky Bay, and the mouth of the Yana River. The first surveys of the shores of the Laptev Sea from the mouth of the Lena to the northern shores of Taimyr were carried out in 1735-36 by Lieutenant V.V. Pronchishchev. The previous names of the sea were Siberian, from the end of the 19th century - Nordenskiöld, established in 1935 modern name in honor of naval officers, participants in the 2nd Kamchatka expedition of V.I. Bering, cousins D.Ya. Laptev and Kh.P. Laptev, who completed surveys of its continental coasts and compiled the first reliable map of this area. The New Siberian Islands were discovered by Siberian hunters in 1712-1812. The first reliable maps of the islands were compiled by the government expedition of Lieutenant P. F. Anjou in 1821-23. The Severnaya Zemlya archipelago was discovered in 1913 by a hydrographic expedition of the Arctic Ocean, led by Senior Lieutenant B.A. Vilkitsky. A map of the coasts of Severnaya Zemlya was compiled by the expedition of G. A. Ushakov in 1930-32.
Economic use. The Laptev Sea is characterized as an area of low economic use. Fishing has local significance. Among the commercial species are Arctic char, Siberian whitefish, omul, nelma, sturgeon, vendace, and muksun. Mammals are represented by walruses, seals, and beluga whales. Polar bears breed on the islands. On the banks there are white arctic fox and lemmings. The world of birds is diverse, especially in bird colonies, where guillemots and guillemots nest; numerous species of gulls and skuas; common polar owl, etc.
Laptev Sea - part of the Northern sea route. The main port is Tiksi, where cargo is transshipped between river and sea. Cargo transportation is dominated by timber, building materials, furs, and food products. Sea freight transportation is carried out under icebreaker assistance. The Laptev Sea is promising in terms of oil and gas content, but its development is difficult due to harsh natural conditions.
Ecological situation. In general, the ecological situation in the Laptev Sea is characterized as favorable due to the weak economic use of this area. The shallow parts of the sea are slightly polluted, resulting in eutrophication of bays, gulfs, and coastal areas of the sea; a decrease in the size of aquatic organisms is observed.
Lit.: Dobrovolsky A.D., Zalogin B.S. Seas of the USSR. M., 1982; Atlas of the Arctic. M., 1985; Tectonic map of the Kara and Laptev seas and northern Siberia / Edited by N. A. Bogdanov, V. E. Khain. M., 1998; Zalogin B.S., Kosarev A.N. Seas. M., 1999; Geoecology of the shelf and coasts of the seas of Russia / Edited by N. A. Aibulatov. M., 2001.