Climatic conditions of the Sea of ​​Japan. Sea of ​​Japan (shores in Russia). Water circulation and currents

The Sea of ​​Japan is inherently semi-enclosed inland. The Sea of ​​Japan is connected in the south through the Korea Strait with the East China and Yellow Seas, in the east through the Tsugaru (Sangara) Strait with the Pacific Ocean, in the north and northeast through the La Perouse and Nevelskoy Straits with Sea of ​​Okhotsk. The length of the Sea of ​​Japan from north to south is 2255 km, from west to east about 1070 km. The area of ​​the water surface is 1062 thousand km².

The Sea of ​​Japan enters the Pacific Ocean, is located between the mainland of Eurasia and its Korean Peninsula in the west, the Japanese Islands and about. Sakhalin in the east and southeast. Washes the shores of Russia, North Korea, South Korea and Japan. Length coastline 7600km

The boundaries of the sea pass through the following points:

• 1. Cape Lazarev 46°42"57"N 143°12"41"E
• 2. Cape swivel 42°40"23"N 133°2"26"E
• 3. Cape Gromov 74°18"23"N 111°12"32"E
• 4. Cape Perish 52°13"26"N 141°38"41"E
• 5. Cape Korsakov 50°1"12"N 142°8"23"E
• 6. Cape Belkin 45°49"13"N 137°41"27"E

There are no large skeletons in the waters of the Sea of ​​Japan. Among the small islands, the most famous are: Moner, Rebun, Oshima, Sado, Askold, Russian, Putyatin. All these islands are located near the coast. The predominant part of the islands is located in the east of the sea.

Most large bays: Peter the Great, East Korean, Ishikari (Hokkaido), Toyama and Wakasa (Honshu).

Characteristics of the bottom topography (maximum depth, average depth, soil, main banks, basins, hollows).

The greatest depth is 3742m (41°20? N 137°42? E).

The average depth is 1536m.

In the relief of the bottom of the Sea of ​​Japan, there are: a shelf, a continental slope, deep-water basins and underwater heights. The deep-water basin is divided by the Yamato, Kita-Oki and Oka underwater heights into 3 depressions - the Central (maximum depth 3699m), Honshu (3063m) and Tsushima (2300m).

The soil is predominantly rocky-sandy;

Primorsky current:

The Primorskoye Current begins in the Tatar Strait and runs from north to south along the eastern coast of Primorsky Krai. The waters of the current are cold, dense, heavy; in the Tatar Strait, they are heavily desalinated by the waters of the Amur River. At Cape Povorotnoy, the current branches, the stronger part goes to the open sea, and the other branch, which merges with the North Korean Current, heads to the coast of Korea. The speed of the Primorsky Current is about 1 km/h, in places 2-2.5 km/h. The width of the current is approximately 100 km, the thickness of the layer carried by it is 50 m.

The Tsushima Current enters the Sea of ​​Japan through a rather narrow one (47 km). Tsushima Strait, which causes a relatively low current speed - about 0.5 - 1 km / h. Further, the current runs from south to north in the eastern part of the Sea of ​​Japan. It is the Tsushima Current that determines the noticeable temperature difference in the eastern part of the Sea of ​​Japan (Japanese coast) compared to its colder western part (Russian Federation), where the cold waters of the Sea of ​​Okhotsk penetrate through the Tatar Strait. The temperature difference reaches 5--6 °C in winter, and 1--3 °C in summer. Therefore, the Japanese coast has a subtropical climate, while the Russian coast has a temperate one.

The Primorsky and Tsushima currents create the main counterclockwise circulation of the waters of the Sea of ​​Japan.

The water temperature on the surface in winter varies from -1.3 - 0 ° C in the north and northwest to 11 - 12 ° C in the south and southeast. In summer the temperature varies from 17°C in the north to 26°C in the south. Wherein East End the sea is 2--3 °C warmer than the western one. Salinity in the east is 34.1--34.8‰, in the west 33.7--33.9, in the north in some areas it decreases to 27.5‰.

According to ice conditions, the Sea of ​​Japan can be divided into three areas: the Tatar Strait, the area along the coast of Primorye from Cape Povorotny to Cape Belkin, and Peter the Great Bay. In winter, ice is constantly observed only in the Tatar Strait and Peter the Great Bay, in the rest of the water area, with the exception of closed bays and bays in the northwestern part of the sea, it is not always formed. According to long-term data, the duration of the period with ice in Peter the Great Bay is 120 days, and in the Tatar Strait - from 40-80 days in the southern part of the strait, to 140-170 days in its northern part.

In the Sea of ​​Japan, the ice cover reaches its maximum development in mid-February. On average, 52% of the area of ​​the Tatar Strait and 56% of the Peter the Great Bay are covered with ice.

The melting of ice begins in the first half of March. In mid-March, the open waters of Peter the Great Bay are cleared of ice and all seaside to Cape Zolotoy. The boundary of the ice cover in the Tatar Strait recedes to the northwest, and in the eastern part of the strait, ice is clearing at this time. Early clearing of the sea from ice occurs in the second decade of April, later - in late May - early June.

The main ports and their brief characteristics.

Main ports: Vladivostok, Nakhodka, Vostochny, Sovetskaya Gavan Vanino, Alexandrovsk-Sakhalinsky, Kholmsk, Niigata, Tsuruga, Maizuru, Wonsan, Hyungnam, Chongjin, Busan.

The Sea of ​​Japan is inhabited by the usual set of commercial fish for the Far Eastern seas - flounder, cod, mackerel, smelt, herring, saury, cod, pollock, etc. Crustaceans - shrimp and crabs are also fished.

Physical and geographical characteristics and hydrometeorological conditions

The Sea of ​​Japan is located in the northwestern part of the Pacific Ocean between the mainland coast of Asia, the Japanese Islands and Sakhalin Island at the geographical coordinates 34°26"-51°41" N, 127°20"-142°15" E. According to its physical and geographical position, it belongs to the marginal oceanic seas and is fenced off from adjacent basins by shallow water barriers. In the north and northeast, the Sea of ​​Japan connects with the Sea of ​​Okhotsk straits Nevelskoy and Laperouse (Soya), in the east - with the Pacific Ocean by the Sangar (Tsugaru) Strait, in the south - with the East China Sea Korean (Tsushima) Strait. The shallowest of them, the Nevelskoy Strait, has a maximum depth of 10 m, and the deepest Sangar Strait is about 200 m. Subtropical waters coming through the Korea Strait from the East China Sea have the greatest influence on the hydrological regime of the basin. The width of this strait is 185 km, and the greatest depth of the threshold is 135 m. The second largest water exchange, the Sangar Strait, has a width of 19 km. The La Perouse Strait, the third largest in terms of water exchange, has a width of 44 km and a depth of up to 50 m. The surface area of ​​the sea surface is 1062 thousand km 2, and the total volume of sea water is 1631 thousand km 3.

The nature bottom topography The Sea of ​​Japan is divided into three parts: northern - north of 44° N, central - between 40° and 44° N. and southern - south of 40 ° N.L. The bottom surface of the northern bathymetric step, which is a wide trench, gradually rising to the north, merges at 49 ° 30 "N with the surface of the shallows of the Tatar Strait. The basin of the central part with maximum depths for the sea (up to 3700 m) has a flat bottom and is elongated from west to east, northeast. From the south, its boundary is defined by the Yamato Sea Rise. The southern part of the sea has the most complex bottom relief. The main geological feature here is the Yamato Sea Rise, formed by two ridges elongated in an east-northeast direction and located between between the Yamato Rise and the slope of Honshu Island lies the Honshu Basin with depths of about 3000 m. depths of 120-140 m.

A feature of the bottom morphology of the Sea of ​​Japan is a poorly developed shelf, which stretches along the coast in a strip from 15 to 70 km in most of the water area. The narrowest shelf strip with a width of 15 to 25 km is observed along the southern coast of Primorye. The shelf is most developed in Peter the Great Bay, in the northern part of the Tatar Strait, in the East Korean Bay and in the area of ​​the Korea Strait.

The total length of the coastline of the sea is 7531 km. It is slightly indented (with the exception of Peter the Great Bay), sometimes almost straight. A few islands lie mainly near the Japanese Islands and in Peter the Great Bay.

The Sea of ​​Japan is located in two climatic zones: subtropical and temperate. Within these zones, two sectors with different climatic and hydrological conditions are distinguished: the severe cold northern sector (partially covered with ice in winter) and the soft, warm sector adjacent to Japan and the coast of Korea. The main factor that forms the climate of the sea is the monsoon circulation of the atmosphere.

The main baric formations that determine atmospheric circulation over the Sea of ​​Japan are the Aleutian Depression, the Pacific Subtropical High, and the Asian Atmospheric Action Center located above the mainland. Changes in their position during the year determine the monsoonal nature of the climate in the Far East. In distribution atmospheric pressure over the Sea of ​​Japan, determined by the main baric formations, the following features are found: a general decrease in pressure from west to east, an increase in pressure from north to south, an increase in the excess of winter pressure values ​​over summer pressure in the direction from northeast to southwest, as well as a pronounced seasonal variability. In the annual course of pressure, most of the sea is characterized by the existence of a maximum pressure in winter and a minimum in summer. In the northeastern part of the sea - near the northern half of about. Khonshu, oh Hokkaido and off the southern coast of Sakhalin have two pressure maxima: the first - in February and the second - in October, with a minimum in summer. The amplitudes of the annual pressure variation, as a rule, decrease from south to north. Along the mainland coast, the amplitude decreases from 15 mb in the south to 6 mb in the north, and along the coast of Japan, from 12 to 6 mb, respectively. The absolute amplitude of pressure fluctuations in Vladivostok is 65 mb, and on about. Hokkaido - 89 mb. To the southeast, in the central and southern parts of Japan, it increases to 100 mb. The main reason for the increase in the amplitudes of pressure fluctuations in the southeast direction is the passage of deep cyclones and typhoons.

The above features of the distribution of atmospheric pressure determine General characteristics wind regime over the Sea of ​​Japan. Near the mainland coast in the cold season, strong winds of the north-western direction prevail with speeds of 12-15 m/s. The frequency of these winds in the period from November to February is 60 - 70%. In January and February, the frequency of prevailing winds at some points on the coast reaches 75 - 90%. From north to south, wind speeds gradually decrease from 8 m/s to 2.5 m/s. Along the insular east coast, the winds of the cold season are not as pronounced in direction as they are off the mainland coast. Wind speeds are less here, but also decrease on average from north to south. Every year, in late summer and early autumn, tropical cyclones (typhoons) enter the Sea of ​​Japan, accompanied by hurricane-force winds. During the cold season, the frequency of storm winds caused by deep cyclones sharply increases. In the warm period of the year, south and southeast winds prevail over the sea. Their frequency is 40 - 60%, and the speeds, as in winter, on average decrease from north to south. In general, the wind speed in the warm season is much less than in winter. During the transitional seasons (spring and autumn), the direction and speed of the wind undergo significant changes.

For open areas of the northwestern regions of the sea, winds of northwestern and northern directions are predominant in winter. In the direction to the southwest, the winds turn from northwest to west, and in the areas adjacent to southern Sakhalin and Hokkaido, from northwest to north and even to northeast. In the warm season, such a regular picture of the general structure of the wind field cannot be established for the entire sea. However, it is found that in northern regions the seas are dominated by east and northeast winds, and in the south - south directions.

In the Sea of ​​Japan air temperature regularly changes both from north to south, and from west to east. In the northern, more severe climate zone, the average annual temperature is 2 °, and in the south, in the subtropics - + 15 °. In the seasonal course of air temperature, the minimum takes place in the winter months (January - February), and the maximum - in August. In the north, the average monthly temperature in January is about -19°, and the absolute minimum is -32°. In the south, the average monthly temperature in January is 5°, and the absolute minimum is -10°. In August, in the north, the average temperature is 15 °, and the absolute maximum is + 24 °; in the south, respectively, 25° and 39°. Temperature changes from west to east have a smaller amplitude. West Coast throughout the year it is colder than the east, with temperature differences increasing from south to north. In winter they are larger than in summer, and average 2°, but at some latitudes they can reach 4 - 5°. Number of cold days (with average temperature below 0°) decreases sharply from north to south.

On the whole, the sea has a negative (about 50 W/m) annual radiative heat balance on the surface, which is compensated by a constant heat inflow from the waters flowing through the Korea Strait. The water balance of the sea is determined mainly by its water exchange with adjacent basins through three straits: Korea (tributary), Sangar and La Perouse (drain). Compared to the value of water exchange through the straits, the contribution to the water balance of precipitation, evaporation, and continental runoff is negligibly small. The continental runoff, due to its insignificance, exerts its influence only in coastal areas seas .

The main factors determining hydrological regime Sea of ​​Japan are the interaction of its surface waters with the atmosphere against the background of changing climatic conditions and water exchange through the straits with adjacent water basins. The first of these factors is decisive for the northern and northwestern parts of the sea. Here, under the action of the northwestern monsoon winds, which bring cold air masses from the continental regions in the winter season, surface waters cool significantly as a result of heat exchange with the atmosphere. At the same time, an ice cover is formed in the shallow areas of the mainland coast, Peter the Great Bay and the Tatar Strait, and convection processes develop in the adjacent open areas of the sea. Convection covers significant layers of water (down to depths of 400-600 m), and in some abnormally cold years it reaches the bottom layers of the deep-water basin, ventilating the cold, relatively homogeneous deep water mass, which makes up 80% of the total volume of sea water. Throughout the year, the northern and northwestern parts of the sea remain colder than the southern and southeastern parts.

Water exchange through the straits has a dominant effect on the hydrological regime of the southern and eastern half of the sea. The subtropical waters of the Kuroshio branches flowing through the Korea Strait throughout the year warm the southern regions of the sea and the waters adjacent to the coast of the Japanese Islands up to the La Perouse Strait, as a result of which the waters of the eastern part of the sea are always warmer than the western.

This section summarizes the basic information about the spatial distribution and variability of temperature and salinity. sea ​​water, water masses, currents, tides and ice conditions of the Sea of ​​Japan, based on published works and analysis of the Atlas graphic material. All values ​​of air and water temperature are given in degrees Celsius (o C), and salinity - in ppm (1 g/kg = 1‰).

On maps of the horizontal distribution of water temperature on the surface, the northern and southern parts of the sea are clearly separated by thermal front, whose position during all seasons of the year remains approximately constant. This front separates the warm and saline waters of the southern sector of the sea from the colder and fresher waters of the northern part of the sea. The horizontal temperature gradient on the surface across the front changes throughout the year from maximum values ​​of 16°/100 km in February to minimum values ​​of 8°/100 km in August. In November-December, north of the main front, a secondary front forms parallel to the Russian coast with a gradient of 4°/100 km. The temperature difference within the entire sea area in all seasons remains almost constant and equal to 13-15°. The warmest month is August, when temperatures in the north are 13-14°, and in the south, in the Korea Strait, they reach 27°. The lowest temperatures (0 ... -1.5 0) are typical for February, when ice forms in the northern shallow areas, and in the Korea Strait the temperature drops to 12-14 °. Quantities seasonal changes surface water temperatures generally increase from southeast to northwest from minimum values ​​(12-14 0) near the Korea Strait to maximum values ​​(18-21 0) in the central part of the sea and near the bay. Peter the Great. Relative to the average annual values, negative temperature anomalies occur from December to May (during the winter monsoon), and positive ones - from June to November (summer monsoon). The strongest cooling (negative anomalies up to -9°) occurs in February in the area of ​​40-42° N, 135-137° E, and the greatest heating (positive anomalies over 11°) is observed in August near Petra Bay Great.

With increasing depth, the range of spatial changes in temperature and its seasonal fluctuations at different horizons narrows significantly. Already at the horizon of 50 m, seasonal temperature fluctuations do not exceed 4-10 0 . The maximum amplitudes of temperature fluctuations at this depth are observed in the southwestern part of the sea. At a horizon of 200 meters, the average monthly values ​​of water temperature in all seasons increase from 0-1 0 in the north of the sea - up to 4-7 ° in the south. The position of the main front here does not change with respect to the surface front, but its meandering is manifested in the area between 131° and 138° E. In the central part of the basin to the north of the main front, the temperature at this horizon is 1-2 0 , and to the south it increases abruptly to 4-5°. At a depth of 500 m, the temperature within the entire sea varies slightly. It is 0.3-0.9 ° and practically does not experience seasonal variations. The frontal separation zone does not manifest itself at this depth, although in the area adjacent to the coast of Japan and Korea, there is a slight increase in temperature due to the transfer of heat to the deep layers by eddy formations that are actively formed in this area of ​​the sea.

Of the regional features of the horizontal temperature distribution, upwelling zones, eddy formations, and coastal fronts should be noted.

Upwelling southern shores Primorye is intensively developed in late October - early November, however, individual cases of its fleeting manifestation can be identified in September - early October. The diameter of the cold water spot in the upwelling zone is 300 km, and the temperature difference between its center and the surrounding waters can reach 90. The occurrence of upwelling is due not only to an increase in deep-water circulation, but also, mainly, to the monsoon change of winds, which is timed precisely for this period of time. Strong northwest winds blowing from the mainland create favorable conditions for the development of upwelling in this area. At the end of November, under the influence of cooling, the stratification in the upwelling zone is destroyed and the temperature distribution on the surface becomes more uniform.

In the coastal zone of the northwestern part of the Sea of ​​Japan (in the region of the Primorsky current), the frontal section is formed at the beginning of summer against the background of a general increase in the temperature of the surface layer. The main front runs parallel to the coastline. In addition to it, there are secondary fronts oriented perpendicular to the coast. In September-October, the main front is present only in the northern part of the sea, and to the south there are separate patches of cold water, limited by fronts. It is possible that the appearance of cold water cells near the coast is due to the rapid cooling of the surface layer in shallow water areas. These waters, after the final destruction of the thermocline, spread towards the open part of the sea in the form of continuous intrusions.

The most active eddy formations are formed on both sides of the front and, covering a significant water column, introduce anomalies into the field of the horizontal temperature distribution.

The absence of water exchange between the Sea of ​​Japan and neighboring basins at depths of more than 200 m, as well as active ventilation of deep layers due to autumn-winter convection in the northern and northwestern regions, lead to a clear division of the water column into two layers: active layer, characterized by seasonal variability, and deep, where both seasonal and spatial variability are almost non-existent. According to existing estimates, the boundary between these layers is located at depths of 300-500 m. Extreme depths (400-500 m) are confined to the southern part of the sea. This is due to the downward movement of water observed here in the center of the vast anticyclonic meander of the East Korea Current, as well as to variations in the position of the frontal zone at its northern and eastern boundaries. Up to a horizon of 400 m, seasonal temperature fluctuations are traced off the coast of Japan, which is a consequence of the subsidence of waters in anticyclonic gyres formed during the interaction of the Tsushima current with the continental slope. High penetration depths of seasonal temperature fluctuations (up to 400-500 m) are found in the Tatar Strait. This is mainly due to convective processes and significant seasonal variability of parameters. surface water, as well as with the intra-annual variability of the intensity and spatial position of the branch of the waters of the Tsushima Current. Off the coast of southern Primorye, seasonal variations in water temperature appear only in the upper three hundred meter layer. Below this limit, seasonal temperature fluctuations are almost not traced. As can be seen from the vertical sections of the temperature field, the characteristics of the active layer undergo significant changes not only in the seasonal course, but also from region to region. The waters of the deep layer, which occupies about 80% of the volume of the sea, are weakly stratified and have a temperature of 0.2 to 0.7°.

The thermal structure of the waters of the active layer consists of the following elements (layers): quasi-homogeneous layer(VKS), seasonal jump layer temperature and main thermocline. The characteristics of these layers in different seasons in the sea have regional differences. Off the coast of Primorsky Krai in the summer, the lower boundary of the UQL is at a depth of 5-10 m, and in southern regions in the sea, it deepens to 20–25 m. In February, the lower boundary of the UML in the southern sector is at depths of 50–150 m. The seasonal thermocline intensifies from spring to summer. In August, the vertical gradient in it reaches a maximum of 0.36°/m. In October, the seasonal thermocline collapses and merges with the main thermocline, which is located throughout the year at depths of 90-130 m. In the central regions of the sea, the noted patterns persist against the background of a general decrease in contrasts. In the northern and northwestern parts of the sea, the main thermocline is weakened, and sometimes completely absent. The seasonal thermocline begins to form here with the beginning of the spring warming of the waters and exists until the winter period, when it is completely destroyed by convection within the entire water column of the active layer.

Horizontal distribution of salinity

Large-scale features of salinity distribution on the surface are determined by the water exchange of the sea with neighboring sea basins, the balance of precipitation and evaporation, ice formation and ice melting, as well as continental runoff in coastal areas.

In the winter season, on most of the sea surface, the salinity of the waters exceeds 34, which is mainly due to the inflow of high-salinity waters (34.6) from the East China Sea. Less saline waters are concentrated in the coastal regions of the Asian continent and islands, where their salinity decreases to 33.5-33.8. In the coastal areas of the southern half of the sea, the salinity minimum on the surface is observed in the second half of summer and early autumn, which is associated with heavy rainfall in the second half of summer and desalination of water brought from the East Kamchatka Sea. In the northern part of the sea, in addition to the summer-autumn decrease, a second salinity minimum is formed in spring during the period of ice melting in the Tatar Strait and Peter the Great Bay. The highest salinity values ​​in the southern half of the sea fall in the spring summer season when the inflow of saline Pacific waters from East China Sea. Characterized by a gradual delay in salinity maxima from south to north. If in the Korea Strait the maximum occurs in March-April, then off the northern coast of Honshu Island it is observed in June, and near the La Perouse Strait - in August. Along the mainland coast, the maximum salinity occurs in August. The most saline waters are located near the Korea Strait. In spring, these features are mostly preserved, but the area of ​​low salinity values ​​in coastal areas increases due to the melting of ice and an increase in continental runoff, as well as the amount of precipitation. Further, by summer, following the entry into the sea through the Korea Strait of freshened surface waters of the East China Sea due to the abundance of precipitation, the general background of salinity in the sea water area decreases to values ​​less than 34. In August, the range of salinity variability within the entire sea is 32.9-33.9. At this time, in the north of the Tatar Strait, salinity decreases to 31.5, and in some parts of the coastal zone - to 25-30. In autumn, with the strengthening of the northern winds, the waters of the upper layer are displaced and mixed, and a slight increase in salinity is observed. The minimum seasonal changes in salinity on the surface (0.5-1.0) are observed in the central part of the sea, and the maximum (2-15) - in the coastal areas of the northern, northwestern parts and in the Korea Strait. At greater depths, along with a general increase in salinity values, there is a sharp decrease in the range of its variability both in space and in time. According to long-term average data, already at a depth of 50 m, seasonal changes in salinity in the central part of the sea do not exceed 0.2-0.4, and in the north and south of the water area - 1-3. At the 100 m horizon, horizontal changes in salinity fit into the range of 0.5, and at the 200 m horizon (Fig. 3.10) in all seasons of the year they do not exceed 0.1, i.e. values ​​characteristic of deep waters. Somewhat higher values ​​are observed only in the southwestern part of the sea. It should be noted that the horizontal salinity distributions at depths greater than 150–250 m are very similar: the minimum salinities are confined to the northern and northwestern parts of the sea, and the maximum salinities are confined to the southern and southeastern parts. At the same time, the haline front, which is weakly expressed at these depths, completely repeats the outlines of the thermal one.

Vertical distribution of salinity

The vertical structure of the salinity field in different parts of the Sea of ​​Japan is characterized by significant diversity. In the northwestern part of the sea, a monotonous increase in salinity with depth is observed in all seasons of the year, with the exception of winter, when it is practically constant throughout the entire water column. In the southern and southeastern parts of the sea, during the warm period of the year, an intermediate layer of increased salinity is clearly distinguished below the freshened surface waters, formed by highly saline waters (34.3-34.5) entering through the Korea Strait. Its core is located at depths of 60-100 m in the north and somewhat deeper - in the south of the sea. To the north, the salinity in the core of this layer decreases and reaches 34.1 on the periphery. In the winter season, this layer is not expressed. At this time of the year, vertical changes in salinity in most of the water area do not exceed 0.6-0.7. In a limited area located to the east of the Korean Peninsula at depths of 100-400 m, an intermediate layer of low salinity is distinguished, which is formed in the winter season due to the subsidence of surface waters in the frontal section zone. The salinity in the core of this layer is 34.00-34.06. Seasonal changes in the vertical structure of the salinity field are clearly visible only in the upper 100–250 m layer. Max Depth penetration of seasonal fluctuations in salinity (200-250 m) is noted in the zone of distribution of the waters of the Tsushima current. This is due to the peculiarities of the intra-annual variation of salinity in the subsurface Pacific waters entering the sea through the Korea Strait. At the top of the Tatar Strait, off the coast of Primorye, Korea, as well as in the area to the south and southwest of the hall. Peter the Great, seasonal salinity variations appear only in the upper 100-150-meter layer. Here, the influence of the waters of the Tsushima Current is weakened, and intra-annual changes in the salinity of the surface water layer, associated with the processes of ice formation and river runoff, are limited to the waters of bays and bays. This area with minimum values ​​of the depth of manifestation of seasonal salinity fluctuations is interspersed with zones with higher values, the origin of which is associated with the penetration of branches of high-salinity waters of the Tsushima Current to the northwestern shores of the sea. A general idea of ​​the vertical structure of the salinity field is given by the spatial sections of the distribution of this characteristic and the tabular values ​​given in the atlas.

water masses

In accordance with the considered features of the spatiotemporal variability of temperature and salinity, the water column of the Sea of ​​Japan is composed of various water masses, the classification of which is carried out mainly according to the extreme elements of the vertical distribution of salinity.

By vertical the water masses of the open part of the Sea of ​​Japan are divided into surface, intermediate and deep. superficial the water mass (its varieties: PSA - subarctic, PVF - front zones, PST - subtropical) is located within the upper mixed layer and is bounded from below by the seasonal thermocline. In the southern warm sector, it (PST) is formed as a result of mixing of waters coming from the East China Sea and the coastal waters of the Japanese Islands, and in the cold northern sector (PSA), it is formed by mixing of coastal waters freshened by continental runoff with waters of open areas of the adjacent part of the sea. As shown above, during the year the temperature and salinity of surface waters vary in a wide range, and their thickness varies from 0 to 120 m.

In the below intermediate During the warm period of the year, a water mass of increased salinity is released in the water layer in most of the sea (its varieties: PPST - subtropical, PPST - transformed), the core of which is located at a depth of 60-100 m, and the lower boundary at a depth of 120-200 meters. Salinity in its core is 34.1-34.8. In a local area to the east of the coast of the Korean Peninsula, at depths of 200-400 m, a water mass of low (34.0-34.06) salinity is sometimes released.

Deep the water mass, usually called the water of the Sea of ​​Japan itself, covers the entire lower layer (deeper than 400 m) and is characterized by uniform temperature (0.2-0.7 °) and salinity (34.07-34.10). The high content of dissolved oxygen in it indicates an active renewal of the deep layers by surface waters.

IN coastal areas in the northwestern part of the sea, due to significant freshening by continental runoff, aggravation of tidal phenomena, wind upwellings and winter convection, a specific coastal water structure is formed, represented by a vertical combination of surface waters (SS) that are less saline than the waters of adjacent areas of the open sea, and have more significant fluctuations in temperature, as well as subsurface water (SSW) of higher salinity and low temperature, formed during winter convection. In some areas (Tatar Strait, Peter the Great Bay), during intense ice formation in winter, highly saline (up to 34.7 and very cold (up to -1.9 0) water mass (LS) is formed. Spreading near the bottom, it can reach the edge of the shelf and drain along the continental slope, participating in the ventilation of the deep layers.

In the part of the shelf, where freshening by continental runoff is small, the water stratification is weakened or even destroyed by tidal mixing. As a result, a weakly stratified shelf structure is formed, consisting of a relatively cold desalinated surface shelf water mass (SH) and a relatively warm and desalinated deep water shelf modification (DSW). With certain directions of the prevailing winds, this structure is distorted by the upwelling phenomenon. In winter, it is destroyed by a more powerful mechanism - convection. The waters formed in the zones of tidal mixing are drawn into the circulation existing in the northwestern part of the sea and propagate beyond the area of ​​their formation, usually considered as the “waters of the Primorsky current.”

Note: In February, the surface and deep water masses of the subarctic structure do not differ in their thermohaline characteristics.

Water circulation and currents

The main elements of the water circulation scheme given in the atlas are the warm currents of the southern and eastern and cold currents of the northwestern sectors of the sea. Warm currents are initiated by the influx of subtropical waters entering through the Korea Strait and are represented by two streams: the Tsushima Current, consisting of two branches - calm-seaward and more turbulent, moving under the very shore of the island of Honshu, and the East Korean Current, propagating in a single stream along the coast of the Korean Peninsula. At a latitude of 38-39 ° N The East Korean current divides into two branches, one of which, going around the Yamato Rise from the north, follows the direction of the Sangar Strait, the other, deviating to the southeast, closes the anticyclonic circulation near the southern coast of Korea with part of the water, and the other merges with the seaward branch Tsushima current. The union of all branches of the Tsushima and East Korean currents into a single flow occurs at the Sangar Strait, through which the main part (70%) of the incoming warm subtropical waters is carried out. The rest of these waters move further north towards the Tatar Strait. Upon reaching the La Perouse Strait, the bulk of this flow is carried out of the sea, and only an insignificant part of it, spreading within the Tatar Strait, gives rise to a cold current that spreads southward along the mainland coast of Primorye. Divergence zone at 45-46°N this current is divided into two parts: the northern - the Limannoye (Shrenk) current and the southern - the Primorsky current, which is divided into two branches south of Peter the Great Bay, one of which gives rise to the cold North Korean current, and the other turns south and, in contact with northern flow of the East Korea Current, forms a large-scale cyclonic gyre centered at 42°N, 138°E. over the Sea of ​​Japan basin. The cold North Korean Current reaches 37° N, and then merges with the powerful flow of the warm East Korean Current, forming, together with the southern branch of the Primorsky Current, a frontal separation zone. The least pronounced element of the general circulation pattern is the West Sakhalin Current, which follows southward from latitude 48°N. along the south coast of Sakhalin and transferring part of the water flow of the Tsushima Current, which separated from it in the waters of the Tatar Strait.

During the year, the noted features of water circulation are practically preserved, but the power of the main currents changes. In winter, due to a decrease in the inflow of water, the speed of both branches of the Tsushima current does not exceed 25 cm/s, and the coastal branch has a greater intensity. The total current width of about 200 km remains in summer, but the velocities increase to 45 cm/s. The East Korean Current also intensifies in summer, when its velocities reach 20 cm/s and its width is 100 km, and attenuates in winter to 15 cm/s and decreases in width to 50 km. The velocities of cold currents throughout the year do not exceed 10 cm/s, and their width is limited to 50-70 km (with a maximum in summer). In the transitional seasons (spring, autumn), the characteristics of the currents have average values ​​between summer and winter. The current velocities in layer 0-25 are almost constant, and with a further increase in depth, they decrease to half the surface value at a depth of 100 meters. The atlas contains schemes of water circulation on the surface of the Sea of ​​Japan in different seasons, obtained by calculation methods.

Tidal phenomena

Tidal motions in the Sea of ​​Japan are predominantly formed by the semidiurnal tidal wave M, which is almost purely standing, with two amphidromic systems located near the boundaries of the Korea and Tatar Straits. Synchronous fluctuations in the tidal profile of the sea level and tidal currents in the Tatar and Korea straits are carried out according to the law of a two-nodal seiche, the antinode of which covers the entire central deep-water part of the sea, and the nodal lines are located near the boundaries of these straits.

In turn, the relationship of the sea with adjacent basins through three main straits contributes to the formation of an induced tide in it, the influence of which, based on morphological features (the shallowness of the straits compared to the depth of the sea), affects the straits and areas immediately adjacent to them. Semidiurnal, diurnal and mixed tides are observed in the sea. The greatest level fluctuations are observed in the extreme southern and northern regions of the sea. At the southern entrance to the Korea Strait, the tide reaches 3 m. As you move north, it quickly decreases and does not exceed 1.5 m near Pusan. In the middle part of the sea, the tides are small. Along the eastern shores of Korea and the Russian Primorye, to the entrance to the Tatar Strait, they are no more than 0.5 m. The tides are of the same magnitude near the western shores of Honshu, Hokkaido and southwestern Sakhalin. In the Tatar Strait, the magnitude of the tides is 2.3-2.8 m. The increase in the magnitude of the tides in the northern part of the Tatar Strait is due to its funnel-shaped shape.

In the open areas of the sea, semidiurnal tidal currents with velocities of 10-25 cm/s are mainly manifested. The tidal currents in the straits are more complex, where they also have very significant velocities. Thus, in the Sangar Strait, tidal currents reach 100–200 cm/s, in the La Perouse Strait, 50–100 cm/s, and in the Korean Strait, 40–60 cm/s.

Ice conditions

According to ice conditions, the Sea of ​​Japan can be divided into three areas: the Tatar Strait, the area along the coast of Primorye from Cape Povorotny to Cape Belkin, and Peter the Great Bay. In winter, ice is constantly observed only in the Tatar Strait and Peter the Great Bay, in the rest of the water area, with the exception of closed bays and bays in the northwestern part of the sea, it is not always formed. The coldest region is the Tatar Strait, where more than 90% of all ice observed in the sea is formed and localized in the winter season. According to long-term data, the duration of the period with ice in Peter the Great Bay is 120 days, and in the Tatar Strait - from 40-80 days in the southern part of the strait, to 140-170 days in its northern part.

The first appearance of ice occurs at the tops of bays and gulfs, closed from the wind, waves and having a desalinated surface layer. In moderate winters, in Peter the Great Bay, the first ice forms in the second decade of November, and in the Tatar Strait, in the tops of Sovetskaya Gavan, Chekhachev and Nevelskoy Straits, primary ice forms are observed already in early November. Early ice formation in Peter the Great Bay (Amur Bay) occurs in early November, in the Tatar Strait - in the second half of October. Later - at the end of November. In early December, the development of ice cover along the coast of Sakhalin Island is faster than near the mainland coast. Accordingly, in the eastern part of the Tatar Strait at this time there is more ice than in the western part. By the end of December, the amount of ice in the eastern and western parts equalizes, and after reaching the parallel of Cape Surkum, the direction of the edge changes: its displacement along the Sakhalin coast slows down, and along the mainland it becomes more active.

In the Sea of ​​Japan, the ice cover reaches its maximum development in mid-February. On average, 52% of the area of ​​the Tatar Strait and 56% of the Peter the Great Bay are covered with ice.

The melting of ice begins in the first half of March. In mid-March, the open waters of Peter the Great Bay and the entire seaside coast to Cape Zolotoy are cleared of ice. The boundary of the ice cover in the Tatar Strait recedes to the northwest, and in the eastern part of the strait, ice is clearing at this time. Early clearing of the sea from ice occurs in the second decade of April, later - in late May - early June.

Hydrological conditions of the hall. Peter the Great and coastal

zones of Primorsky Krai

Peter the Great Bay is the largest in the Sea of ​​Japan. It is located in the northwestern part of the sea between the parallels 42 0 17 "and 43 ° 20" N. sh. and meridians 130°41" and 133°02" E. e. The waters of Peter the Great Bay are limited from the sea side by a line connecting the mouth of the Tumannaya River (Tyumen-Ula) with Cape Povorotny. Along this line, the width of the bay reaches almost 200 km.

The Muraviev-Amursky peninsula and a group of islands located to the south-west of it, Peter the Great Bay is divided into two large bays: Amursky and Ussuriysky. Amur Bay represents the northwestern part of Peter the Great Bay. From the west, it is bounded by the coast of the mainland, and from the east - by the mountainous Muravyov-Amursky peninsula and the Russky, Popov, Reinike, and Rikord islands. The southern boundary of the Amur Bay is the line connecting Cape Bruce with the islands of Tsivolko and Zheltukhin. The bay extends in a northwesterly direction for about 70 km, and its width, averaging 15 km, varies from 13 to 18 km. Ussuri Bay occupies the northeastern part of Peter the Great Bay. From the northwest, it is bounded by the Muravyov-Amursky Peninsula, Russky Island, and southwest of last islands. The southern boundary of the bay is considered to be a line connecting the southern ends of the Zheltukhin and Askold islands.

The area of ​​Peter the Great Bay is about 9 thousand km2, and the total length of the coastline, including the islands, is about 1500 km. On the vast water area of ​​the bay there are many different areas islands, concentrated mainly in the western part of the bay in the form of two groups. The northern group is located southwest of the Muravyov-Amursky Peninsula and is separated from it by the Bosphorus-Vostochny Strait. This group consists of four large and many small islands. Russky Island is the largest in this group. The southern group - the Rimsky-Korsakov Islands - includes eight islands and many islets and rocks. The most significant in it is the island of Big Pelis. In the eastern part of the bay there are two more large islands: Putyatina, located in the middle of Strelok Bay, and Askold, lying southwest of Putyatina Island.

most significant strait is the Bosphorus-East, separating the Russky Island from the Muravyov-Amur Peninsula. The straits between the Rimsky-Korsakov Islands are deep and wide; between the islands adjacent directly to the Muravyov-Amursky peninsula, the straits are narrower.

The coastline of Peter the Great Bay is very winding and forms many secondary bays and coves. The most significant of them are the bays of Posyet, Amursky, Ussuriysky, Strelok, Vostok and Nakhodka (America). Slavyansky Bay, Tabunnaya, Narva and Perevoznaya bays jut into the western shore of the southern part of the Amur Bay. The coastline of the northeastern part of the Amur and northwestern parts of the Ussuri Bay is relatively slightly indented. On the eastern shore of the Ussuri Bay, the bays of Sukhodol, Andreeva, Telyakovsky, Vampausu and Podyapolsky stand out. Capes protruding far into the sea form rocky, mostly steep coasts, bordered by stones. The largest of peninsulas are: Gamow, Bruce and Muravyov-Amursky.

Bottom relief Peter the Great Bay is characterized by developed shallow water and a steep continental slope cut by underwater canyons. The continental slope runs 18 and 26 miles south of the Askold and Rikord Islands almost parallel to the line connecting the mouth of the Tumannaya River and Cape Povorotny. The bottom in Peter the Great Bay is quite flat and gradually rises from south to north. In the eastern part of the bay, the depths reach 100 m or more, and in the western part they do not exceed 100 m. Seaward from the entrance to the bay, the depths increase sharply. On the continental slope, in a strip 3 to 10 miles wide, the depths vary from 200 to 2000 m. The secondary bays - Amur, Ussuri, Nakhodka - are shallow. In the Amur Bay, the bottom topography is quite even. Extensive shallows stretch from the shores of the bay's summit. From the northwestern coast of Russky Island to the opposite shore of the bay, an underwater rapid stretches with depths of 13-15 m. At the entrance to the Ussuri Bay, the depths are 60-70 m, then they decrease to 35 m in the middle part of the bay and to 2-10 m at the top . In the Nakhodka Bay, the depths at the entrance reach 23-42 m, in the middle part 20-70 m, and the top of the bay is occupied by shallow water with depths of less than 10 m.

Meteorological regime Peter the Great Bay, determine the monsoon circulation of the atmosphere, the geographical position of the area, the impact of the cold Primorsky and warm Tsushima (in the south) currents. cold continental air from the mainland to the sea (winter monsoon). As a result, frosty, slightly cloudy weather with a small amount of precipitation and a predominance of northerly and northwesterly winds sets in Peter the Great Bay. In spring, the wind regime is unstable, the air temperature is relatively low and long periods of dry weather are possible. The summer monsoon operates from May-June to August-September. At the same time, sea air is transported to the mainland and warm weather is observed with a relatively large amount of precipitation and fog. Autumn in Peter the Great Bay is the best time of the year - usually warm, dry, with a predominance of clear, sunny weather. Warm weather lasts in some years until the end of November. The generally stable monsoonal weather pattern is often disrupted by intense cyclonic activity. The passage of cyclones is accompanied by an increase in cloudiness to continuous, rainfall, deterioration in visibility and significant storm activity. The average annual rainfall in the Vladivostok region reaches 830 mm. Atmospheric precipitation is minimal in January and February (10-13 mm). The summer period accounts for 85% of the annual precipitation and in August an average of 145 mm falls. In some years, precipitation, comparable in amount to monthly norms, can be bursty, short-term in nature and lead to natural disasters.

In the annual course of long-term average monthly values atmospheric pressure the minimum (1007-1009 mb) is observed in June-July, and the maximum (1020-1023 mb) in December-January. In the Amursky and Ussuriysky bays, the range of pressure fluctuations from maximum to minimum values ​​gradually increases with distance from coastal areas to more continental ones. Short-term changes in pressure during the daily course reach 30-35 mb and are accompanied by sharp fluctuations in wind speed and direction. The actually recorded maximum pressure values ​​in the Vladivostok region are 1050-1055 mb.

Average annual t air temperature is approximately 6 °. The coldest month of the year is January, when the average monthly air temperature in the northern part of the Amur and Ussuri bays is -16°…-17°. At the top of the Amur and Ussuri bays, the air temperature can drop to -37°. The warmest month of the year is August, when the average monthly temperature rises to +21°C.

During the winter monsoons, from October-November to March, winds northern and northwestern directions. In the spring, when the winter monsoon changes to the summer monsoon, the winds are not very stable. In summer, southeasterly winds prevail in the bay. Calm is more often observed in summer. The average annual wind speed varies from 1 m/s (at the top of the Amur Bay) to 8 m/s (Askold Island). On some days the wind speed can reach 40 m/s. In summer, the wind speed is less. In the peaks of the Amur and Ussuri bays, the average monthly wind speed is 1 m/s, in bays and gulfs - 3-5 m/s. Storms are mainly associated with cyclonic activity and are observed mainly in the cold season. The largest number of days with a storm wind is observed in December-January and is 9-16 per month. In the peaks of the Amur and Ussuri bays, storm winds are not observed annually.

They come to Peter the Great Bay typhoons, originating in tropical latitudes, in the region of the Philippine Islands. Approximately 16% of all tropical cyclones originating there predominantly in August-September come to the Sea of ​​Japan and Primorsky Krai. Their paths of movement are very diverse, but none repeats the trajectory of the other exactly. If the typhoon does not enter Peter the Great Bay and is still observed only in the southern part of the Sea of ​​Japan, it still affects the weather in this area: it rains heavily and the wind increases to a storm.

Hydrological characteristic

Horizontal temperature distribution

Surface water temperatures experience significant seasonal variability, mainly due to the interaction of the surface layer with the atmosphere. In spring, the water temperature in the surface layer in the water area of ​​the bay varies within 4-14°. At the tops of the Amur and Ussuri bays, it reaches 13-14° and 12°, respectively. In general, the Amur Bay is characterized by higher temperatures than the Ussuri Bay. In summer, the waters of the bay warm up well. At this time, it reaches 24-26° in the tops of the Amur and Ussuri Bays, 18° in the America Bay, and 17° in the open part of the bay. In autumn, the temperature drops to 10-14° in the secondary bays and to 8-9° in the open part. In winter, the entire mass of water cools, its temperature fluctuates from 0 to -1.9 °. Negative temperatures occur throughout the shallow waters, as well as in secondary bays. The position of the 0° isotherm approximately coincides with the 50-meter isobath. At this time, the waters of the open part of the bay are warmer than the coastal ones and are characterized by positive temperature values. With increasing depth, the range of temperature change decreases and already at a depth of 50 m does not exceed 3 °, and at depths of more than 70 meters, seasonal changes almost do not appear.

Vertical temperature distribution

In the warm period of the year (April-November) there is a monotonous decrease in temperature with depth. At this time, a layer of seasonal thermocline is formed on the subsurface horizons - everywhere, except for shallow water, where the entire water column warms up and mixes well. In autumn, from the beginning of the winter monsoon and cooling, cold deep waters rise in shallow water and a second layer of temperature jump forms at a depth of 40 m. In December, both layers of the temperature jump are destroyed under the influence of convection, and the temperature remains constant throughout the entire winter period (from December to March) within the entire water column of the bay.

Salinity distribution

The orographic conditions of the bay and the influence of continental runoff create a peculiar regime of salinity distribution and variability. The water in some coastal areas of the bay desalinates to brackish, and in open areas it is close to the salinity of the adjacent part of the sea. The annual course of salinity is characterized by a minimum in summer and a maximum in winter. In spring, on the surface, the minimum salinity values ​​are confined to the top of the Amur Bay, where they are 28. At the top of the Ussuri Bay, salinity is 32.5, while in the rest of the water area it rises to -33-34. In summer, the surface layer is exposed to the greatest freshening. At the head of the Amur Bay, salinity is 20%, and in general in coastal waters and secondary bays it does not exceed 32.5 and increases in open areas to 33.5. In autumn, the horizontal distribution of salinity is similar to that in spring. In winter, salinity is close to 34 throughout the entire water area of ​​the bay. At depths of more than 50 meters, salinity varies within the water area of ​​the bay in the range of 33.5-34.0.

With increasing depth, salinity, as a rule, increases (spring-autumn) or remains constant (winter). In the bottom layer of the bay, due to the process of salinization during the formation of ice in the winter months, high-density waters are formed with a temperature of less than -1.5°C and a salinity of 34.2-34.7. In extremely ice years, high-density waters, spreading near the bottom, reach the edge of the shelf, roll down the slope and ventilate the deep layers of the sea.

water masses

In the winter season, in the Peter the Great Bay, the characteristics of water within the entire thickness correspond to the deep water mass of the Sea of ​​Japan (temperature is less than 1 °, salinity is about 34). In the near-bottom 20-meter layer during this period of time, a water mass of increased density with low (up to -1.9 °) temperature and high (up to 34.8º) salinity is released, which disappears already in mid-March, mixing with the surrounding waters.

In the summer season, due to an increase in heat inflow and continental runoff, the water column is stratified. In coastal areas, especially in areas where fresh water flows from river mouths, there is an estuary water mass with low (average 25) salinity, high (average 20°) temperature in the summer season, and depth of distribution up to 5-7 meters. The water masses of the open areas of the bay are divided by a seasonal thermocline into: surface coastal, which extends to the limit from the surface to a depth of 40 m and has indices in summer: temperature - 17-22 °, salinity - 30-33; subsurface - up to a depth of 70 m with a temperature of 2-16 ° and salinity of 33.5-34.0; and deep shelf - below the horizon of 70 m to the bottom with a temperature of - 1-2 ° and a salinity of about 34.

currents

The water circulation in the Peter the Great Bay is formed under the influence of the constant currents of the Sea of ​​Japan, tidal, wind and runoff currents. In the open part of the bay, the Primorsky Current is clearly visible, which propagates in a southwestern direction at velocities of 10-15 cm/s. In the southwestern part of the bay, it turns south and gives rise to the North Korean Current, which is most pronounced on subsurface horizons. In the Amursky and Ussuriysky bays, the influence of the Primorsky current is clearly manifested only in the absence of wind, when an anticyclonic water circulation is formed in the Ussuriysky bay, and a cyclonic one in the Amursky one. Wind, tidal phenomena and the runoff of the Razdolnaya River (in the Amur Bay) cause a significant restructuring of the current field. Schemes of the main components of the total currents of the Amur and Ussuri Bays, given in the atlas, show that the greatest contribution is made by wind currents, which in the winter season enhance the anticyclonic circulation in the Ussuri Bay, and change it to cyclonic in summer. During the passage of cyclones, the velocities of the total currents on the surface can reach 50 cm/s.

Tidal phenomena

A semidiurnal tidal wave enters Peter the Great Bay from the southwest and spreads to the secondary bays of Posyet, Ussuriysky and America. She circles the bay in less than one hour. The time of the onset of high water of the semidiurnal tide is slowed down in closed bays and secondary bays separated by islands and peninsulas. The maximum possible tide value (during the day) in the bay is 40-50 cm. northwestern region, where the maximum level slightly exceeds 50 cm, and least of all - in the Ussuriysky Bay and the strait between about. Putyatin and the mainland (tide up to 39 cm). Tidal currents in the bay are insignificant and their maximum velocities do not exceed 10 cm/s.

Ice conditions

The ice regime of the area practically does not prevent regular navigation throughout the year. In the bay, ice occurs in the winter season in the form of fast ice and drift ice. The beginning of ice formation begins in mid-November in the bays of the Amur Bay. At the end of December, most of the bays of the Amur and partly of the Ussuri bays are completely covered with ice. Drifting ice is observed in the open part of the sea. The maximum development of the ice cover reaches in late January - mid-February. From the end of February, the ice situation becomes lighter, and in the first half of April, the bay water area is usually completely cleared of ice. In severe winters, especially in the first ten days of February, the ice reaches great concentration, which excludes the possibility of ships navigating without the use of an icebreaker.

Hydrochemical characteristics

In this version of the atlas, hydrochemical characteristics are presented in the form of maps of the distribution of average annual values ​​of dissolved oxygen (ml/l), phosphates (μM), nitrates (μM), silicates (μM) and chlorophyll (μg/l) at different horizons for winter, spring , summer and autumn without additional description. In the source of data used (WOA"98), the time frames of the hydrological seasons are defined as follows: Winter: January-March. Spring: April-June. Summer: July-September. Autumn: October-December.

Hydrological-acoustic characteristics

The main changes in sound speed values, both seasonal and spatial, occur in the 0-500 m layer. The difference in sound speed values ​​in the same season on the sea surface reaches 40-50 m/s, and at a depth of 500 m - 5 m/s. With. The maximum values ​​are noted in the southern and southeastern parts seas, and the minimum - in the northern and northwestern. The range of seasonal changes in the speed of sound in both zones is approximately the same and reaches 35-45 m/s. The frontal zone runs from the southwest to the northeast through the central part of the sea. Here, in the 0-200 m layer, the maximum horizontal gradients of sound speed values ​​are observed at any time of the year (from 0.2 s‾¹ in summer to 0.5 s‾¹ in winter). At the same time, the maximum changes in the horizontal sound speed values ​​are observed in summer at a depth of 100 m.

According to the vertical distribution of the speed of sound in the southern and southeastern parts of the sea, we can distinguish:

• the upper homogeneous layer, the thickness of which varies from 50 to 150 m during the year, with sound speeds of more than 1490-1500 m/s;
• a jump layer of sound speed values ​​with large negative gradients (on average 0.2-0.4 s‾¹), extending to a depth of 300 m;
• layer 300-600 m with minimum values ​​(and gradients) of sound speed;
• deeper than 600 m, there is a constant increase in the speed of sound, mainly due to an increase in hydrostatic pressure.

The PZK axis is located at depths of 300–500 m, and off the coast of Japan at 40º N. sh. drops to 600 m. The sound channel extends from the surface to the bottom.

In the northern and northwestern parts of the sea, a homogeneous layer, but with minimal sound speeds (less than 1455 m/s) is formed in winter and is associated with winter convection. The layer thickness can reach 600 m, thus forming a surface sound channel. In the rest of the year, changes in sound speed with depth are characterized by negative gradients, increasing from spring to autumn up to 0.5–0.8 s constant value of the gradient. The UZK axis with minimum sound speeds of 1455-1460 m/s in this part of the sea comes to the surface in winter, and from spring to autumn it gradually drops to a depth of 200-300 m. When moving south in the front area, the UZK axis sharply deepens to 300 m In the central part of the sea, the width of the sound channel in winter does not exceed 1000-1200 m, in spring it increases to 1500 m, and in summer and early autumn it is determined only by the depth of the place.

The Sea of ​​Japan belongs to the Pacific Ocean basin and is a marginal sea, which is separated from the Pacific Ocean by the Japanese Islands and Sakhalin Island. The Sea of ​​Japan washes the shores of Russia and Japan.

Sea characteristic

Major port cities at sea: Vladivostok, Nakhodka, Vanino and Sovetskaya Gavan.

The coastline of the sea is slightly indented, but has several bays, the largest of which are the bays of Olga, Peter the Great, Ishikari and East Korea Bay.

More than 600 species of fish live in the waters of the Sea of ​​Japan.

Economic use of the sea

Along with industrial fishing, mussels, scallops, squid and seaweed (kelp and seaweed) are harvested.
Vladivostok is final destination Trans-Siberian Railway, where the transshipment base is located, where cargo is reloaded from railway cars to sea cargo ships.

Ecology of the Sea of ​​Japan

In ancient times, tribes of the Mongolian race lived on the western shores of the Sea of ​​Japan. At the same time, the Japanese islands were settled by the ancestors of the Japanese - the Malay and Polynesian Yamato tribes.

Archaeological research was first carried out on Sakhalin Island in 1867, when during archaeological excavations at the southern tip near Lake Lebyazhye, the first artifacts were found confirming the existence of ancient settlements on Sakhalin Island.

The Sea of ​​Japan is a marginal sea of ​​the Pacific Ocean and is limited by the shores of Japan, Russia and Korea. The Sea of ​​Japan communicates through the Korea Strait in the south with the East China and Yellow Seas, through the Tsugaru (Sangara) Strait in the East with the Pacific Ocean, and through the La Perouse and Tatar Straits in the north with the Sea of ​​Okhotsk. The area of ​​the Sea of ​​Japan is 980,000 km2, the average depth is 1361 m. The northern boundary of the Sea of ​​Japan runs along 51 ° 45 "N (from Cape Tyk on Sakhalin to Cape South on the mainland). The southern boundary runs from Kyushu Island to the Goto Islands and from there to Korea [Cape Kolcholkap (Izgunov)]

The Sea of ​​Japan has an almost elliptical shape with a major axis in the southwest to northeast direction. Along the coast there are a number of islands or island groups - these are the islands of Iki and Tsushima in the middle part of the Korean Strait. (between Korea and the island of Kyushu), Ulleungdo and Takashima off the east coast of Korea, Oki and Sado off the west coast of the island of Honshu (Hondo) and Tobi Island off the northwestern coast of Honshu (Hondo).

Bottom relief

The straits connecting the Sea of ​​Japan with the marginal seas of the Pacific Ocean are characterized by shallow depths; only the Korea Strait has depths of more than 100 m. Bathymetrically, the Sea of ​​Japan can be divided by 40°N. sh. into two parts: north and south.

The northern part has a relatively flat bottom relief and is characterized by a general smooth slope. The maximum depth (4224 m) is observed in the region of 43°00" N, 137°39" E. d.
The bottom relief of the southern part of the Sea of ​​Japan is quite complex. In addition to the shallow waters around the islands of Iki, Tsushima, Oki, Takashima and Ulleungdo, there are two large isolated
banks separated by deep grooves. This is the Yamato Bank, opened in 1924, in the region of 39°N, 135°E. and the Shunpu Bank (also called the Yamato North Bank), discovered in 1930 and located at about 40 ° N. sh., 134 ° in. e. The smallest depths of the first and second banks are 285 and 435 m, respectively. A depression more than 3000 m deep was found between the Yamato Bank and the island of Honshu.

Hydrological regime

water masses

Sea of ​​Japan can be divided into surface, intermediate and deep. The surface water mass occupies a layer up to approximately 25 m and is separated from the underlying waters in summer by a clearly defined thermocline layer. The surface water mass in the warm sector of the Sea of ​​Japan is formed by the mixing of surface waters of high temperature and low salinity coming from the East China Sea and the coastal waters of the Japan Islands region, in the cold sector - by the mixing of waters formed during the melting of ice from early summer to autumn , and waters of Siberian rivers.

For the surface water mass, the largest fluctuations in temperature and salinity are observed depending on the season of the year and the region. Thus, in the Korea Strait, the salinity of surface waters in April and May exceeds 35.0 ppm. which is higher than the salinity in the deeper layers, but in August and September the salinity of surface waters drops to 32.5 ppm. At the same time, in the area of ​​the island of Hokkaido, salinity varies only from 33.7 to 34.1 ppm. In summer surface water temperature 25°C, but in winter it varies from 15°C in the Korea Strait to 5°C near the sea. Hokkaido. In coastal areas near Korea and Primorye, salinity changes are small (33.7-34 ppm). The intermediate water mass below the surface water in the warm sector of the Sea of ​​Japan has a high temperature and salinity. It is formed in the intermediate layers of Kuroshio west of Kyushu and flows from there into the Sea of ​​Japan from early winter to early summer.

However, according to the distribution of dissolved oxygen, intermediate water can also be observed in the cold sector. In the warm sector, the core of the intermediate water mass is located approximately in the 50 m layer; salinity is about 34.5 ppm. The intermediate water mass is characterized by a rather strong decrease in temperature along the vertical - from 17 ° C at a depth of 25 m to 2 ° C at a depth of 200 m. The thickness of the layer of intermediate water decreases from the warm sector to the cold; in this case, the vertical temperature gradient for the latter becomes much more pronounced. The salinity of intermediate waters is 34.5–34.8 ppm. in the warm sector and about 34.1 prom. in the cold. The highest salinity values ​​are noted here at all depths - from the surface to the bottom.

The deep water mass, commonly referred to as the water of the Sea of ​​Japan itself, has extremely uniform temperature (about 0-0.5 ° C) and salinity (34.0-34.1 ppm). More detailed studies by K. Nishida, however, showed that the temperature of deep waters below 1500 m rises slightly due to adiabatic heating. At the same horizon, a decrease in the oxygen content to a minimum is observed, in connection with which it is more logical to consider waters above 1500 m as deep, and below 1500 m as near-bottom. Compared with the waters of other seas, the oxygen content in the Sea of ​​Japan at the same depths is exceptionally high (5.8–6.0 cm3/l), which indicates an active renewal of water in the deep layers of the Sea of ​​Japan. The deep waters of the Sea of ​​Japan are formed mainly in February and March as a result of the subsidence of surface waters in the northern part of the Sea of ​​Japan due to horizontal diffusion, cooling in winter and subsequent convection, after which their salinity rises to approximately 34.0 ppm.

Sometimes surface waters of low salinity in the cold sector (1-4°C, 33.9 p.m.) wedged into the polar front and deepened to the south, leaving under the intermediate waters of the warm sector. This phenomenon is analogous to the intrusion of subarctic intermediate water below the warm Kuroshio layer in the Pacific Ocean in the region north of Japan.

Salinity in spring and summer warm waters from the East China Sea and cold waters east of Korea is decreasing due to precipitation and ice melting. These less saline waters mix with the surrounding waters and the overall salinity of the surface waters of the Sea of ​​Japan decreases. In addition, these surface waters gradually warm up during the warmer months. As a result, the density of surface waters decreases, which leads to the formation of a well-defined upper thermocline layer separating surface waters from underlying intermediate waters. The layer of the upper thermocline is located in the summer season at a depth of 25 m. In autumn, heat is transferred from the sea surface to the atmosphere. As a result of mixing with the underlying water masses, the temperature of surface waters decreases, and their salinity increases. The emerging intense convection leads to the deepening of the upper thermocline layer to 25–50 m in September and 50–100 m in November. In autumn, the intermediate waters of the warm sector are characterized by a decrease in salinity due to the inflow of waters from the Tsushima Current with lower salinity. At the same time, convection in the surface water layer intensifies during this period. As a result, the thickness of the intermediate water layer decreases. In November, the layer of the upper thermocline disappears completely due to the mixing of the overlying and underlying waters. Therefore, in autumn and spring, only the upper homogeneous layer of water and the underlying cold layer are observed, separated by a layer of the lower thermocline. The latter for most of the warm sector is located at a depth of 200–250, but to the north it rises and near the coast of Hokkaido is located at a depth of about 100 m. In the warm sector of the surface layer, temperatures reach a maximum in mid-August, although in the northern part of the Sea of ​​Japan they spread to the depths. The minimum temperature is observed in February-March. On the other hand, the maximum temperature of the surface layer near the coast of Korea is observed in August. However, due to the strong development of the upper thermocline layer, only a very thin surface layer is heated. Thus, temperature changes in the 50–100 m layer are almost entirely due to advection. Due to the low temperatures characteristic of most of the Sea of ​​Japan at fairly great depths, the waters of the Tsushima Current cool down significantly as they move north.

The waters of the Sea of ​​Japan are characterized by exceptionally high levels of dissolved oxygen, partly due to abundant phytoplankton. The oxygen content at almost all horizons is about 6 cm3/l and more. Particularly high oxygen content is observed in surface and intermediate waters, with maximum value at the horizon of 200 m (8 cm3/l). These values ​​are much higher than at the same and lower levels in the Pacific Ocean and the Sea of ​​Okhotsk (1-2 cm3/l).

Surface and intermediate waters are most saturated with oxygen. The percentage of saturation in the warm sector is 100% or slightly lower, and the waters near Primorsky Krai and Korea are oversaturated with oxygen due to low temperatures. Off the northern coast of Korea, it is 110% or even higher. In deep waters, there is a very high oxygen content to the very bottom.

Color and transparency

The color of the water of the Sea of ​​Japan (according to the color scale) in the warm sector is more blue than in the cold one, corresponding to the region of 36-38 ° N. latitude, 133–136° E e. index III and even II. In the cold sector, this is mainly the color of indices IV-VI, and in the Vladivostok region it is above III. In the northern part of the Sea of ​​Japan, a greenish color of sea water is noted. Transparency (according to the white disk) in the region of the Tsushima current is more than 25 m. In the cold sector, it sometimes drops to 10 m.

Currents of the Sea of ​​Japan

The Tsushima Current, about 200 km wide, washes the coast of Japan and moves further to the NE at a speed of 0.5 to 1.0 knots. Then it is divided into two branches - the warm Sangara current and the warm La Perouse current, which exit respectively into the Pacific Ocean through the Tsugaru (Sangarsky) Strait and into the Sea of ​​Okhotsk through the La Perouse Strait. Both of these currents, after passing through the straits, turn to the east and run respectively near the eastern coast of the island of Honshu and the northern coast of the island of Hokkaido.

Three cold currents are observed in the Sea of ​​Japan: the Liman current, which moves at low speed to the southwest in the area north of Primorsky Krai, the North Korean current, which goes south in the Vladivostok region to eastern Korea, and the Primorskoye, or cold current in the middle part of the Sea of ​​Japan, which originates in the area Tatar Strait and goes to the central part of the Sea of ​​Japan, mainly to the entrance to the Tsugaru (Sangara) Strait. These cold currents form a counterclockwise circulation and in the cold sector of the Sea of ​​Japan contains clearly defined layers of surface and intermediate water masses. Between the warm and cold currents there is a clear boundary of the "polar" front.

Since the Tsushima current contains surface and intermediate water masses, which are about 200 m thick, and is separated from the underlying deep water, the thickness of this current is basically of the same order.

The current velocity to a depth of 25 m is almost constant, and then decreases with depth to 1/6 of the surface value at a depth of 75 m. The flow rate of the Tsushima Current is less than 1/20 of the Kuroshio Current flow rate.

The speed of cold currents is about 0.3 knots for the Liman Current and less than 0.3 knots for the Primorsky Current. The cold North Korea Current, which is the strongest, has a speed of 0.5 knots. This current is 100 km wide and 50 m thick. In general, cold currents in the Sea of ​​Japan are much weaker than warm ones. The average speed of the Tsushima Current passing through the Korean Strait is less in winter, and increases to 1.5 knots in summer (in August). For the Tsushima current, interannual changes are also noted, with a clear period of 7 years being distinguished. The inflow of water into the Sea of ​​Japan mainly occurs through the Korea Strait, since the inflow through the Tatar Strait is very insignificant. The flow of water from the Sea of ​​Japan occurs through the Tsugaru (Sangara) Strait and La Perouse.

Tides and tidal currents

Tidal waves propagate at right angles to these cotidal lines. To the west of Sakhalin and in the area of ​​the Korean Strait. two points of amphidromy are observed. A similar cotidal map can be constructed for the lunisolar diurnal tide. In this case, the point of amphidromy is in the Korea Strait. Since total area cross section of the La Perouse and Tsugaru straits is only 1/8 of the cross section of the Korea Strait, and the cross section of the Tatar Strait is generally insignificant, then the tidal wave comes here from the East China Sea mainly through east passage(Tsushima Strait). The magnitude of forced fluctuations in the mass of water in the entire Sea of ​​Japan is practically negligible. The resulting component of tidal currents and the Tsushima Current going to the east sometimes reaches 2.8 knots. In the Tsugaru (Soigaru) Strait, a diurnal tidal current prevails, but the magnitude of the semidiurnal tide is greater here.

In tidal currents, diurnal inequality is clearly expressed. tidal current in the La Perouse Strait is less pronounced due to the difference in levels between the Sea of ​​Okhotsk and the Sea of ​​Japan. There is also a daily disparity here. In the La Perouse Strait, the current is directed mainly to the east; its speed sometimes exceeds 3.5 knots.

Ice Conditions

The melting of ice begins in the areas most distant from the coast. In the second half of March, the Sea of ​​Japan, with the exception of areas close to the coast, is already free of ice. In the northern part of the Sea of ​​Japan, ice off the coast usually melts in mid-April, at which time navigation resumes in Vladivostok. The last ice in the Tatar Strait is observed in early-mid May. The period of ice cover along the coast of Primorsky Krai is 120 days, and at the De-Kastri harbor in the Tatar Strait - 201 days. Along the northern coast of the DPRK, a large amount of ice is not observed. Near the western coast of Sakhalin, only the city of Kholmsk is free of ice, since a branch of the Tsushima Current enters this area. The remaining areas of this coast freeze for almost 3 months, during which navigation stops.

Geology

The continental slopes of the Japanese Sea basin are characterized by many submarine canyons. From the side of the mainland, these canyons stretch to depths of more than 2000 m, and from the side of the Japanese islands, only up to 800 m. The Sea of ​​Japan is composed of bedrocks consisting of Precambrian granites and other Paleozoic rocks and overlying igneous and sedimentary rocks of the Neogene. According to paleogeographic studies, the southern part of the modern Sea of ​​Japan, probably in the Paleozoic and Mesozoic and during most of the Paleogene, was dry land. From this it follows that the Sea of ​​Japan was formed during the Neogene and early Quaternary period. The absence of a granite layer in the earth's crust in the northern part of the Sea of ​​Japan indicates the transformation of the granite layer into a basalt layer due to basification, accompanied by the subsidence of the earth's crust. The presence of a "new" oceanic crust here can be explained by the stretching of the continents that accompanies the general expansion of the Earth (Agayed's theory).

Thus, we can conclude that the northern part of the Sea of ​​Japan was once dry land. The present presence of such a large amount of continental material at the bottom of the Sea of ​​Japan at depths of more than 3000 m should indicate that the land was lowered to a depth of 2000–3000 m in the Pleistocene.

The Sea of ​​Japan is currently connected to the Pacific Ocean and the marginal seas surrounding it through the Korean, Tsugaru (Saigarsky), La Perouse and Tatar Straits. However, the formation of these four straits took place in very recent geological periods. The oldest strait is the Tsugaru (Sangara) strait; it already existed during the Wisconsin glaciation, although after that it may have been repeatedly clogged with ice and used in the migration of land animals. The Korea Strait was also dry land at the end of the Tertiary period, and through it the migration of elephants of the southern breed to the Japanese islands was carried out. This strait opened only at the beginning of the Wisconsin glaciation. The La Perouse Strait is the youngest. Fossilized remains of mammoths found on the island of Hokkaido indicate the existence of an isthmus. land on the site of this strait until the end of the Wisconsin glaciation

Geographic Encyclopedia

JAPANESE SEA- JAPANESE SEA, a semi-enclosed sea of ​​the Pacific Ocean, between the mainland of Eurasia and the Japanese islands. It washes the shores of Russia, North Korea, the Republic of Korea and Japan. It is connected by the straits: Tatar, Nevelskoy and La Perouse with the Sea of ​​Okhotsk, Tsugaru (Sangara) ... Russian history

JAPANESE SEA Modern Encyclopedia

JAPANESE SEA- Quiet ok. between the mainland of Eurasia and the Japanese about you. It washes the shores of Russia, North Korea, the Republic of Korea and Japan. It is connected by the straits: Tatar, Nevelsk and La Perouse with the Okhotsk m., Tsugaru (Sangar) with the Pacific Ocean, Korean with East China ... Big Encyclopedic Dictionary

Japanese Sea- JAPANESE SEA, the Pacific Ocean, between the mainland of Eurasia and the Japanese islands. It is connected by the Tatar, Nevel and La Perouse straits with the Sea of ​​Okhotsk, Tsugaru (Sangar) with the Pacific Ocean, Korea with the East China Sea. Area 1062 thousand ... ... Illustrated Encyclopedic Dictionary

Japanese Sea- belonging to the Pacific Ocean basin, on the 3rd washes east coast Korea and its continuation to the Russian coast of the Asian continent; on E it is separated from the Pacific Ocean by a group of Japanese islands. The southern boundary of the Ya. Sea is the Korea Strait, ... ... Encyclopedic Dictionary F.A. Brockhaus and I.A. Efron

Japanese Sea- a semi-enclosed sea of ​​the Pacific Ocean between the mainland of Eurasia and its Korean Peninsula in the west, the Japanese Islands and about. Sakhalin in the east and south. It washes the shores of the USSR, North Korea, South Korea, and Japan. The length of the coastline is 7600 km (of which 3240 km ... ... Great Soviet Encyclopedia

Japanese Sea- Japanese Sea. Rudnaya bay. The Sea of ​​Japan, a semi-enclosed sea of ​​the Pacific Ocean, between the mainland of Eurasia and its Korean Peninsula, the Japanese Islands and Sakhalin Island. It washes the shores of Russia, North Korea, the Republic of Korea and Japan. Connects with... ... Dictionary "Geography of Russia"

Japanese Sea- Pacific Ocean, between the mainland of Eurasia and the Japanese islands. It washes the shores of Russia, North Korea, the Republic of Korea and Japan. It is connected by the straits: Tatar, Nevelskoy and La Perouse with the Sea of ​​Okhotsk, Tsugaru (Sangara) with the Pacific Ocean, Korean with ... ... encyclopedic Dictionary

Japanese Sea- Pacific Ocean, east. shores of Eurasia. The name of the sea was given by the Japanese islands, which limit it from the east. Since, in addition to Japan, the sea also washes the shores of Russia and Korea, the use of a name associated with only one of the countries of the basin, South ... ... Toponymic Dictionary

Books

• Japanese Sea. Encyclopedia, Zonn Igor Sergeevich, Kostyanoy Andrey Gennadievich. The publication is dedicated to the Far East natural object- The Sea of ​​Japan, one of the seas of the Pacific Ocean, and the countries surrounding it. The encyclopedia contains more than 1000 articles about ... Buy for 964 rubles
• Japanese Sea. Encyclopedia, I. S. Zonn, A. G. Kostyanoy. The publication is dedicated to the Far Eastern natural object - the Sea of ​​Japan, one of the seas of the Pacific Ocean, and the countries surrounding it. The encyclopedia contains over 1000 articles about…