Sea of Japan (shores in Russia). The nature of the Japanese Sea and its economic importance
The Sea of Japan is, by its nature, internal, semi-enclosed. 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 Nevelsk Straits with the Sea of Okhotsk. The length of the Sea of Japan from north to south is 2,255 km, from west to east about 1,070 km. The area of the water surface is 1062 thousand km².
The Sea of Japan enters the Pacific Ocean, located between the Eurasian mainland and its Korean Peninsula in the west, the Japanese Islands and the island. Sakhalin in the east and southeast. It washes the shores of Russia, North Korea, South Korea and Japan. The length of the coastline is 7600 km
The boundaries of the sea pass through the following points:
- 1. Cape Lazarev 46°42"57"N 143°12"41"E
- 2. Turning cape 42°40"23"N 133°2"26"E
- 3. Cape Gromov 74°18"23"N 111°12"32"E
- 4. Cape Pogibi 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 wrecks in the waters of the Sea of Japan. Among the small islands, the most famous are: Monerom, Rebun, Oshima, Sado, Askold, Russky, Putyatin. All these islands are located near the coast. The predominant part of the islands is located in the east of the sea.
The largest bays are: Peter the Great, East Korean, Ishikari (Hokkaido Island), Toyama and Wakasa (Honshu Island).
Characteristics of the bottom topography (maximum depth, average depth, soil, main banks, basins, depressions).
The greatest depth is 3742 m (41°20? N, 137°42? E).
Average depth 1536m.
The bottom topography of the Sea of Japan is divided into: shelf, continental slope, deep-sea basins and underwater hills. The deep-sea basin is divided by the underwater heights of Yamato, Kita-Oki and Oki into 3 depressions - Central (maximum depth 3699m), Honshu (3063m) and Tsushima (2300m).
The soil is predominantly rocky-sandy;
Primorsky Current:
The Primorsky Current begins in the Tatar Strait and is directed from north to south along the eastern coast of the Primorsky Territory. The waters of the current are cold, dense, heavy, in the Tatar Strait they are highly desalinated by the waters of the Amur River. At Cape Povorotny the current branches, the stronger part goes into the open sea, and the other branch, merging with the North Korean Current, heads towards the shores of Korea. The speed of the Primorsky Current is about 1 km/h, in some places 2-2.5 km/h. The width of the current is approximately 100 km, the thickness of the layer it transports 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 passes 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 Strait of Tartary. The temperature difference reaches 5--6 °C in winter, and 1--3 °C in summer. Therefore, the Japanese coast has a subtropical climate, and the Russian coast has a temperate climate.
The Primorye and Tsushima currents create the main circulation of the waters of the Sea of Japan, directed counterclockwise.
The surface water temperature in winter varies from -1.3--0 °C in the north and northwest to 11--12 °C in the south and southeast. In summer, temperatures vary from 17 °C in the north to 26 °C in the south. At the same time, the eastern part of the sea is 2--3 °C warmer than the western part. 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 Strait of Tartary, 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 does not always form. According to long-term data, the duration of the period with ice in the Peter the Great Gulf 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, ice covers 52% of the area of the Tatar Strait and 56% of the Peter the Great Bay.
Ice melting begins in the first half of March. In mid-March, the open waters of Peter the Great Bay and the entire coastal coast up to Cape Zolotoy are cleared of ice. The ice boundary in the Tatar Strait retreats to the northwest, and in the eastern part of the strait clearing of ice occurs at this time. Early clearing of ice from the sea occurs in the second ten days of April, later - at the end of May - beginning of June.
Main ports and their brief characteristics.
Main ports: Vladivostok, Nakhodka, Vostochny, Sovetskaya Gavan Vanino, Aleksandrovsk-Sakhalinsky, Kholmsk, Niigata, Tsuruga, Maizuru, Wonsan, Hungnam, Chongjin, Busan.
The Sea of Japan is home to the usual range of commercial fish for the Far Eastern seas - flounder, cod, mackerel, smelt, herring, saury, cod, pollock, etc. Crustaceans - shrimp and crabs - are also fished.
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.
Characteristics of the sea
The area of the Sea of Japan is 1062 sq. km. The volume of water is 1630 thousand cubic km. The depth of the sea ranges from 1753 to 3742 meters.The northern waters of the Sea of Japan are covered with ice in winter.
Large 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 the East Korean Gulf.
More than 600 species of fish live in the waters of the Sea of Japan.
Economic use of the sea
For economic purposes, the waters of the Sea of Japan are used in two directions - industrial fishing And transport shipping.Along with industrial fishing, mussels, scallops, squid and seaweed (kelp and seaweed) are harvested.
Vladivostok is the terminus of the Trans-Siberian railway, where there is a transshipment base where cargo is reloaded from railway cars to sea cargo ships.
Ecology of the Sea of Japan
Due to the large number of sea transport vessels and oil tankers in the waters of port cities, cases of pollution of sea waters with oil are not uncommon. The waste products of people and port industrial enterprises also contribute their share to the pollution.Archaeological research on the Sea of Japan.
In ancient times, tribes of the Mongol race lived on the western shores of the Sea of Japan. At the same time, the Japanese islands were populated by the ancestors of the Japanese - the Malay and Polynesian Yamato tribes.
In Russia, information about the Sea of Japan first appeared in the 17th century, after the famous Russian traveler Vasily Poluyarkov rafted down the Amur to its mouth in 1644-1645.
Archaeological research was first carried out on Sakhalin Island in 1867, when during archaeological excavations at the southern tip of Lake Lebyazhye the first artifacts were found confirming the presence of ancient settlements on Sakhalin Island.
In size it is inferior to the sea and, its area is up to 1,062 tons km2, and the deepest depression reaches up to 3,745 m. It is generally accepted that the average depth is 1,535 m. Large depths with a geographical location indicate that the sea belongs to the marginal oceanic seas.
There are medium and small islands in the sea. The most significant of them are Rishiri, Oshima, Sado, Momeron, Russian. Almost all the islands are located along the mainland in the eastern part.
The coastline is slightly indented, the outlines of Sakhalin Island are especially simple. with the Japanese Islands it has a more indented coastline. The main major seaports are Vostochny Port, Wonsan, Kholmsk, Vladivostok, Tsuruga, Chongjin.
Currents of the Sea of Japan
Tides in the Sea of Japan
Tides are expressed differently in different areas of the sea; they are especially pronounced in the summer and reach up to three meters in the Korea Strait. To the north, the tides decrease and do not exceed 1.5 m. This is explained by the fact that the bottom has a funnel shape. The greatest fluctuations are observed in the northern and southern extreme regions of the sea in the summer.
I offer you an interesting video “Parallel World - Sea of Japan” from the “Russian underwater expeditions” series.
—
For many centuries, Japan was isolated from the Asian continent. The first to try to cross the Sea of Japan were the ubiquitous Mongols. At the end of the 13th century. Genghis Khan's grandson Kublai tried to take possession of the islands twice - in 1274 and 1281. Both attempts were unsuccessful. It was not only the courage of the Japanese that stopped the Mongols. The first time, when attacking the island of Kyushu, the invaders were thwarted by a typhoon, and they retreated.
The second time, having thoroughly prepared, the Mongols assembled an army of one hundred thousand and unleashed a fleet of 4,000 ships on the Japanese. But the Sea of Japan hit them with an even more powerful typhoon than the first time. After seven weeks of battle, a storm scattered and destroyed the entire Mongol fleet.
This could not be interpreted otherwise as God’s providence. The Japanese called this wind “kamikaze”, which translated means “divine wind”.
This is one of the few historical dangers that threatened Japan from the outside. Another arose during the Russo-Japanese War. In the waters of the Sea of Japan, near the island of Tsushima, a major battle took place in May 1905, as a result of which the Russian fleet was destroyed.
During the Cold War, both branches of the Korea Strait in the southern Sea of Japan were under US control. The United States Navy, which wanted to maintain control of the Pacific Ocean, observed the actions of the Soviet fleet in Vladivostok.
Today, only passenger and fishing vessels sail in the peaceful waters of the Sea of Japan.
The surface area of this sea is more than a million square kilometers.
It washes the shores of the Russian Far East, both Korean powers and the island of Japan.
The Sea of Japan is part of the Pacific Ocean, but is separated from it by Sakhalin Island and the Japanese Islands. Through the La Perouse Strait (the Japanese call it Soya) between the islands of Sakhalin and Hokkaido, the Sea of Japan is connected to the Sea of Okhotsk, through the Korean Strait to the East China Sea, and the Sangar Strait between Hokkaido and Honshu connects it to the Pacific Ocean. On the Russian shore of the Sea of Japan, Vladivostok is the last point of the Trans-Siberian Railway and an important commercial and military port in Russia.
The greatest depth of the Sea of Japan is 3742 m. In the middle of the basin, the bottom rises and forms the ridges of the Yamato underwater rise. The minimum depth in this place is 285 m. The islands of Hokkaido, Honshu and Kyushu have the craters of 36 still active volcanoes, most of them about 3000 m high. This is one of the areas of the highest seismic activity in the world. Earthquakes often occur here, including underwater ones.
Due to strong geological activity, this area is called the Pacific "hot ring".
On the southwestern coast of the Sea of Japan there are two Korean states - communist North Korea, isolated from the outside world, and South Korea, which is currently experiencing economic prosperity.
The Korea Strait, which separates South Korea from the island of Kyushu, is 180 km wide at its narrowest point, and two currents collide here. Powerful typhoons from the south often besiege Kyushu.
The whole world is in your hands 14-2010
Characteristics of the Sea of Japan
The Sea of Japan lies between the continent of Asia, the Korean Peninsula, and Sakhalin and the Japanese islands, separating it from the ocean and two neighboring seas. In the north, the border between the Sea of Japan and the Sea of Okhotsk runs along the line between Cape Sushchev and Cape Tyk on Sakhalin. In the La Perouse Strait, the border is the line of Cape Soya-m. Crillon. In the Sangar Strait, the border runs along the line of Cape Syria - Cape Estan, and in the Korean Strait - along the line of Cape Nomo (about Kyushu) - Cape Fukae (about Goto) - about. Jeju - Korean Peninsula.
The Sea of Japan is one of the largest and deepest seas in the world. Its area is 1062 km², volume - 1631 thousand km³, average depth -1536 m, greatest depth - 3699 m. This is a marginal oceanic sea.
There are no large islands in the Sea of Japan. Of the small ones, the most significant are the islands of Moneron, Risirn, Okushiri, Ojima, Sado, Okinoshima, Ullyndo, Askold, Russky, and Putyatina. Tsushima Island is located in the Korea Strait. All islands (except Ulleungdo) are located near the coast. Most of them are located in the eastern part of the sea.
The coastline of the Sea of Japan is relatively slightly indented. The simplest in outline is the coast of Sakhalin; the coasts of Primorye and the Japanese Islands are more winding. The large bays of the mainland coast include De-Kastri, Sovetskaya Gavan, Vladimir, Olyi, Peter the Great Posyet, Koreysky, on the island. Hokkaido - Ishikari, on the island. Honshu - Toyama and Wakasa.
The coastal boundaries are cut through by straits that connect the Sea of Japan with the Pacific Ocean, the Sea of Okhotsk and the East China Sea. The straits vary in length, width and, most importantly, depth, which determines the nature of water exchange in the Sea of Japan. Through the Sangar Strait, the Sea of Japan communicates directly with the Pacific Ocean. The depth of the strait in the western part is about 130 m, in the eastern part, where its maximal depths are located, about 400 m. The Nevelskoy and La Perouse straits connect the Sea of Japan and the Sea of Okhotsk. The Korea Strait, divided by the islands of Jeju, Tsushima and Ikizuki into the western (Broughton passage with the greatest depth of about 12.5 m) and eastern (Kruzenshtern passage with the greatest depth of about 110 m) parts, connects the Sea of Japan and the East China Sea. The Shimonoseki Strait, with depths of 2-3 m, connects the Sea of Japan with the Inland Sea of Japan. Due to the shallow depths of the straits and the great depths of the sea itself, conditions are created for isolating its deep waters from the Pacific Ocean and adjacent seas, which is the most important natural feature of the Sea of Japan
The coast of the Sea of Japan, varied in structure and external forms in different areas, belongs to different morphometric types of coasts. These are predominantly abrasive, mostly unaltered, shores. To a lesser extent, the Sea of Japan is characterized by accumulative shores. This sea is surrounded by predominantly mountainous shores. In some places, single rocks - kekurs - characteristic formations of the Sea of Japan coast rise from the water. Low-lying shores are found only on certain sections of the coast.
Climate of the Sea of Japan
The Sea of Japan lies entirely in the monsoon climate zone of temperate latitudes. In the cold season (from October to March) it is influenced by the Siberian anticyclone and the Aleutian low, which is associated with significant horizontal gradients of atmospheric pressure. In this regard, strong northwest winds with speeds of 12-15 m/s and more dominate over the sea. Local conditions change wind conditions. In some areas, under the influence of coastal topography, there is a high frequency of northern winds, while in others, calms are often observed. On the southeast coast, the regularity of the monsoon is disrupted; western and northwestern winds predominate here.
During the cold season, continental cyclones enter the Sea of Japan. They cause strong storms, and sometimes severe hurricanes, which last for 2-3 days. At the beginning of autumn (September), tropical cyclones-typhoons sweep over the sea, accompanied by hurricane winds
The winter monsoon brings dry and cold air to the Sea of Japan, the temperature of which increases from south to north and from west to east. In the coldest months - January and February - the average monthly air temperature in the north is about -20°, and in the south about 5°, although significant deviations from these values are often observed. During the cold seasons, the weather is dry and clear in the northwestern part of the sea, wet and cloudy in the southeast.
In warm seasons, the Sea of Japan is affected by the Hawaiian High and, to a lesser extent, by the depression that forms in the summer over Eastern Siberia. In this regard, southern and southwestern winds prevail over the sea. However, pressure gradients between areas of high and low pressure are relatively small, so wind speeds average 2-7 m/s. A significant increase in wind is associated with the entry of oceanic, and less often continental, cyclones into the sea. In summer and early autumn (July-October), the number of typhoons over the sea increases (with a maximum in September), causing hurricane-force winds. In addition to the summer monsoon, strong and hurricane winds associated with the passage of cyclones and typhoons, local winds are observed in different areas of the sea. They are mainly caused by the peculiarities of coastal orography and are most noticeable in the coastal zone.
The summer monsoon brings warm and humid air. The average monthly temperature of the warmest month - August - in the northern part of the sea is approximately 15°, and in the southern regions about 25°. In the northwestern part of the sea, significant cooling is observed due to the influx of cold air brought by continental cyclones. In spring and summer, cloudy weather with frequent fogs prevails.
A distinctive feature of the Sea of Japan is the relatively small number of rivers flowing into it. The largest of them is Suchan. Almost all rivers are mountainous. Continental flow into the Sea of Japan is approximately 210 km³/year and is fairly evenly distributed throughout the year. Only in July does the river flow increase slightly
Geographical location, the outlines of the sea basin, separated from the Pacific Ocean and adjacent seas by high thresholds in the straits, pronounced monsoons, water exchange through the straits only in the upper layers - the main factors in the formation of the hydrological conditions of the Sea of Japan
The Sea of Japan receives a large amount of heat from the sun. However, the total heat consumption for effective radiation and evaporation exceeds the supply of solar heat; therefore, as a result of processes occurring at the water-air interface, the sea loses heat annually. It is replenished by the heat brought by Pacific waters entering the sea through the straits, therefore, on the average long-term value, the sea is in a state of thermal equilibrium. This indicates the important role of water heat exchange, mainly heat influx from outside.
Significant natural factors are the exchange of water through the straits, the flow of precipitation onto the sea surface and evaporation. The main flow of water into the Sea of Japan occurs through the Korea Strait - about 97% of the total annual amount of incoming water. The largest flow of water flows through the Sangar Strait - 64% of the total flow; 34% flows through the La Perouse and Korean Straits. The share of fresh components of the water balance (continental runoff, precipitation) remains only about 1%. Thus, the main role in the water balance of the sea is played by water exchange through the straits.
Features of the bottom topography, water exchange through the straits, and climatic conditions form the main features of the hydrological structure of the Sea of Japan. It is similar to the subarctic type of structure of the adjacent areas of the Pacific Ocean, but has its own characteristics that have developed under the influence of local conditions.
Temperature and salinity of the Sea of Japan
The entire thickness of its waters is divided into two zones, surface - to a depth of an average of 200 m and deep - from 200 m to the bottom. The waters of the deep zone are relatively uniform in physical properties throughout the year. The characteristics of surface water under the influence of climatic and hydrological factors change in time and space much more intensely.
In the Sea of Japan, three water masses are distinguished: two in the surface zone - the surface Pacific, characteristic of the southeastern part of the sea, and the surface Sea of Japan - for the northwestern part of the sea, and one in the deep part - the deep Sea of Japan water mass.
The surface Pacific water mass is formed by the water of the Tsushima Current; it has the largest volume in the south and southeast of the sea. As you move north, its thickness and area of distribution gradually decrease, and at approximately 48° N, due to a sharp decrease in depth, it pinches out in shallow water. In winter, when the Tsushima Current weakens, the northern boundary of the Pacific waters is located approximately 46-47° from latitude.
Surface Pacific water is characterized by high temperatures (about 15-20°) and salinity (34-34.5°/͚). This water mass contains several layers, the hydrological characteristics of which and thickness vary throughout the year: the surface layer, where the temperature is during the year the temperature varies from 10 to 25°, and the salinity varies from 33.5 to 34.5°/͚. The thickness of the surface layer varies from 10 to 100 m, the upper intermediate layer has a thickness varying from 50 to 150 m. It exhibits significant gradients in temperature, salinity and density, the lower layer has a thickness from 100 to 150 m. Its depth varies throughout the year occurrence and distribution boundaries, temperature varies from 4 to 12°, salinity - from 34 to 34.2°/͚. The lower intermediate layer has very slight vertical gradients in temperature, salinity and density. It separates the surface Pacific water mass from the deep Sea of Japan.
As you move north, the characteristics of Pacific water gradually change under the influence of climatic factors as a result of its mixing with the underlying deep Sea of Japan water. With the cooling and desalination of Pacific water at latitudes 46-48° N, the surface water mass of the Sea of Japan is formed. It is characterized by relatively low temperature (on average about 5-8°) and salinity (32.5-33.5°/͚). The entire thickness of this water mass is divided into three layers: surface, intermediate and deep. As in the Pacific Ocean, in the surface water of the Japanese Sea, the greatest changes in hydrological characteristics occur in the surface layer with a thickness of 10 to 150 m or more. The temperature here varies throughout the year from 0 to 21°, salinity - from 32 to 34°/͚. In the intermediate and deep layers, seasonal changes in hydrological characteristics are insignificant
Deep Sea of Japan water is formed as a result of the transformation of surface waters that descend to depths due to the process of winter convection. The vertical changes in the characteristics of the deep Sea of Japan water are extremely small. The bulk of these waters have a temperature of 0.1-0.2° in winter, 0.3-0.5° in summer, and a salinity throughout the year of 34.1-34.15°/͚.
The structural features of the waters of the Sea of Japan are well illustrated by the distribution of oceanological characteristics in it. Surface water temperatures generally increase from northwest to southeast
In winter, the water temperature on the surface increases from negative values close to 0° in the north and northwest to 10-14° in the south and southeast. This season is characterized by a well-defined contrast in water temperature between the western and eastern parts of the sea, and in the south it is weaker than in the north and central part of the sea. Thus, at the latitude of Peter the Great Bay, the water temperature in the west is close to 0°, and in the east it reaches 5-6°. This is explained, in particular, by the influence of warm waters moving from south to north in the eastern part of the sea.
As a result of spring warming, the surface water temperature throughout the sea rises quite quickly. At this time, temperature differences between the western and eastern parts of the sea begin to smooth out.
In summer, the surface water temperature rises from 18-20° in the north to 25-27° in the south of the sea. Temperature differences across latitude are relatively small
On the western shores, the surface water temperature is 1-2° lower than on the eastern shores, where warm waters spread from south to north.
In winter, in the northern and northwestern regions of the sea, the vertical water temperature changes slightly, and its values are close to 0.2-0.4°. In the central, southern and southeastern parts of the sea, the change in water temperature with depth is more pronounced. In general, the surface temperature, equal to 8-10°, remains up to horizons of 100-150 m, from which it gradually decreases with depth to approximately 2-4° at horizons of 200-250 m, then it decreases very slowly - to 1-1. 5° at horizons of 400-500 m, deeper the temperature drops slightly (to values less than 1°) and remains approximately the same to the bottom.
In summer, in the north and northwest of the sea, high surface temperature (18-20°) is observed in the 0--15 m layer, from here it drops sharply with a depth of up to 4° at a horizon of 50 m, then its decrease is very slow to a horizon of 250 m where it is approximately 1°, deeper and to the bottom the temperature does not exceed 1°.
In the central and southern parts of the sea, the temperature decreases quite smoothly with depth and at a horizon of 200 m is approximately 6°, from here it decreases somewhat faster and at horizons of 250-260 m it is equal to 1.5-2°, then it decreases very slowly at horizons 750-1500 m (in some areas at horizons of 1000-1500 m) reaches a minimum of 0.04-0.14°, from here the temperature rises towards the bottom to 0.3°. The formation of an intermediate layer of minimum temperature values is presumably associated with the immersion of the waters of the northern part of the sea, cooled during severe winters. This layer is quite stable and is observed all year round.
The average salinity of the Sea of Japan, approximately 34.1°/͚, is slightly lower than the average salinity of the waters of the World Ocean.
In winter, the highest salinity of the surface layer (about 34.5°/͚) is observed in the south. The lowest salinity on the surface (about 33.8°/͚) is observed along the southeastern and southwestern coasts, where some desalination is caused by heavy precipitation. In most of the sea, the salinity is 34.1°/͚. In spring, in the north and northwest, desalination of surface water occurs due to melting ice, and in other areas it is associated with an increase in precipitation. Salinity remains relatively high (34.6-34.7°/͚) in the south, where at this time the influx of saltier waters entering through the Korea Strait increases. In summer, the average salinity on the surface varies from 32.5°/͚ in the north of the Tatar Strait to 34.5°/͚ off the coast of the island. Honshu.
In the central and southern regions of the sea, precipitation significantly exceeds evaporation, which leads to desalination of surface waters. By autumn, the amount of precipitation decreases, the sea begins to cool, and therefore the salinity on the surface increases. The vertical variation of salinity is generally characterized by small changes in its values along the depth. In winter, most of the sea experiences a uniform salinity from surface to bottom, equal to approximately 34.1°/͚. Only in coastal waters is there a weakly expressed minimum salinity in the surface horizons, below which the salinity increases slightly and remains almost the same to the bottom. At this time of year, vertical changes in salinity in most of the sea do not exceed 0.6-0.7°/͚, and in its central part do not reach 0.1°/͚.
Spring-summer desalination of surface waters forms the main features of the summer vertical distribution of salinity.
In summer, minimal salinity is observed on the surface as a result of noticeable desalination of surface waters. In subsurface layers, salinity increases with depth, creating noticeable vertical salinity gradients. The maximum salinity at this time is observed at horizons of 50-100 m in the northern regions and at horizons of 500-1500 m in the southern regions. Below these layers, salinity decreases slightly and remains almost unchanged to the bottom, remaining within the range of 33.9-34.1°/͚. In summer, the salinity of deep waters is 0.1°/͚ less than in winter.
The density of water in the Sea of Japan depends mainly on temperature. The highest density is observed in winter, and the lowest in summer. In the northwestern part of the sea the density is higher than in the southern and southeastern
In winter, the surface density is quite uniform throughout the sea, especially in its northwestern part.
In spring, the uniformity of surface density values is disrupted due to different heating of the upper layer of water.
In summer, horizontal differences in surface density values are greatest. They are especially significant in the area of mixing waters with different characteristics. In winter, the density is approximately the same from surface to bottom in the northwestern part of the sea. In the southeastern regions, the density increases slightly at horizons of 50-100 m; deeper and to the bottom it increases very slightly. Maximum density is observed in March
In summer in the northwest, the waters are noticeably interlayered in density. It is small on the surface, rises sharply at horizons of 50-100 m and increases more gradually deeper to the bottom. In the southwestern part of the sea, the density increases noticeably in the subsurface (up to 50 m) layers, at horizons of 100-150 m it is quite uniform, below the density increases slightly to the bottom. This transition occurs at horizons of 150-200 m in the northwest and at horizons of 300-400 m in the southeast of the sea.
In autumn, the density begins to level out, which means a transition to a winter type of density distribution with depth. Spring-summer density stratification determines a fairly stable state of the waters of the Sea of Japan, although it is expressed to varying degrees in different areas. In accordance with this, more or less favorable preconditions are created in the sea for the emergence and development of mixing.
Due to the predominance of winds of relatively low strength and their significant intensification during the passage of cyclones under conditions of water stratification in the north and northwest of the sea, wind mixing penetrates here to horizons of about 20 m. In the less stratified waters of the southern and southwestern regions, the wind mixes the upper layers to the horizons 25-30 m. In autumn, stratification decreases and winds increase, but at this time of year the thickness of the upper homogeneous layer increases due to density mixing.
Autumn-winter cooling, and in the north, ice formation, cause intense convection in the Sea of Japan. In its northern and northwestern parts, as a result of rapid autumn cooling of the surface, convective mixing develops, which covers deep layers within a short time. With the onset of ice formation, this process intensifies, and in December convection penetrates to the bottom. At great depths, it extends to horizons of 2000-3000 m. In the southern and southeastern regions of the sea, cooled to a lesser extent in autumn and winter, convection extends mainly to horizons of 200 m. In areas of sharp changes in depth, convection is enhanced by the sliding of water along slopes, as a result of which density mixing penetrates to horizons of 300-400 m. Below mixing is limited by the density structure of water, and ventilation of the bottom layers occurs due to turbulence, vertical movements and other dynamic processes.
The nature of the circulation of sea waters is determined not only by the influence of the winds acting directly above the sea, but also by the circulation of the atmosphere over the northern part of the Pacific Ocean, since the strengthening or weakening of the influx of Pacific waters depends on it. In summer, the southeast monsoon increases water circulation due to the influx of large amounts of water. In winter, the persistent northwest monsoon prevents the flow of water into the sea through the Korea Strait, causing a weakening of water circulation.
Through the Korea Strait, the waters of the western branch of the Kuroshio, which passed through the Yellow Sea, enter the Sea of Japan and spread in a wide stream to the northeast along the Japanese islands. This flow is called the Tsushima Current. In the central part of the sea, the Yamato Rise divides the flow of Pacific waters into two branches, forming a divergence zone, which is especially pronounced in the summer. In this zone, deep water rises. Having gone around the hill, both branches connect in an area located in the northwest of the Noto Peninsula.
At a latitude of 38-39°, a small flow separates from the northern branch of the Tsushima Current to the west, towards the Korea Strait, and turns into a countercurrent along the coast of the Korean Peninsula. The bulk of the Pacific waters are carried out from the Sea of Japan through the Sangarsky and La Perouse straits, while some of the waters, having reached the Tatar Strait, give rise to the cold Primorsky Current, moving south. South of Peter the Great Bay, the Primorsky Current turns east and merges with the northern branch of the Tsushima Current. A small part of the water continues to move south to Korea Bay, where it flows into the countercurrent formed by the waters of the Tsushima Current.
Thus, moving along the Japanese Islands from south to north, and along the coast of Primorye - from north to south, the waters of the Sea of Japan form a cyclonic gyre centered in the northwestern part of the sea. In the center of the gyre, rising waters are also possible.
In the Sea of Japan, two frontal zones are distinguished - the main polar front, formed by the warm and salty waters of the Tsushima Current and the cold, less saline waters of the Primorsky Current, and the secondary front, formed by the waters of the Primorsky Current and coastal waters, which in summer have a higher temperature and lower salinity than the waters of the Primorsky Current. In winter, the polar front passes slightly south of the parallel of 40° N. w, and near the Japanese Islands it runs approximately parallel to them almost to the northern tip of the island. Hokkaido. In summer, the location of the front is approximately the same, it only moves slightly to the south, and off the coast of Japan - to the west. The secondary front passes close to the coast. Primorye, approximately parallel to them.
The tides in the Sea of Japan are quite distinct. They are created mainly by the Pacific tidal wave entering the sea through the Korea and Sangar Straits.
The sea experiences semi-diurnal, diurnal and mixed tides. In the Korea Strait and in the north of the Tatar Strait there are semi-diurnal tides, on the eastern coast of Korea, on the coast of Primorye, near the islands of Honshu and Hokkaido - diurnal tides, in Peter the Great and Korean Gulfs - mixed.
The nature of the tide corresponds to tidal currents. In open areas of the sea, semidiurnal tidal currents with speeds of 10-25 cm/s are mainly observed. Tidal currents in the straits are more complex, where they have very significant speeds. Thus, in the Sangar Strait, tidal current speeds reach 100-200 cm/s, in the La Perouse Strait - 50-100, in the Korea Strait - 40-60 cm/s.
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 already at Busan it does not exceed 1.5 m.
In the middle part of the sea the tides are low. Along the eastern coasts of the Korean Peninsula and Soviet Primorye, up to the entrance to the Tatar Strait, they are no more than 0.5 m. The tides are of the same magnitude off the western coasts of Honshu, Hokkaido and Southwestern Sakhalin. In the Tatar Strait, the tide height is 2.3-2.8 m. In the northern part of the Tatar Strait, the tide heights increase, which is determined by its funnel-shaped shape.
In addition to tidal fluctuations, seasonal level fluctuations are well expressed in the Sea of Japan. In summer (August - September) the maximum rise in level is observed on all shores of the sea; in winter and early spring (January - April) the minimum level is observed.
In the Sea of Japan, surge level fluctuations are observed. During the winter monsoon off the western coast of Japan, the level can rise by 20-25 cm, and off the mainland coast it can drop by the same amount. In summer, on the contrary, off the coast of North Korea and Primorye the level rises by 20-25 cm, and off the Japanese coast it drops by the same amount.
Strong winds caused by the passage of cyclones and especially typhoons over the sea develop very significant waves, while monsoons cause less strong waves. In the northwestern part of the sea, northwestern waves predominate in autumn and winter, and eastern waves predominate in spring and summer. Most often, disturbances with a force of 1-3 points are observed, the frequency of which varies from 60 to 80% per year. In winter, strong waves prevail - 6 points or more, the frequency of which is about 10%.
In the southeastern part of the sea, thanks to the stable northwest monsoon, waves from the northwest and north develop in winter. In summer, weak, most often southwesterly, waves prevail. The largest waves have a height of 8-10 m, and during typhoons the maximum waves reach a height of 12 m. Tsunami waves are observed in the Sea of Japan.
The northern and northwestern parts of the sea, adjacent to the mainland coast, are covered with ice annually for 4-5 months, the area of which occupies about 1/4 of the entire sea.
The appearance of ice in the Sea of Japan is possible as early as October, and the last ice lingers in the north sometimes until mid-June. Thus, the sea is completely ice-free only during the summer months - July, August and September.
The first ice in the sea forms in closed bays and bays of the mainland coast, for example in Sovetskaya Gavan Bay, De-Kastri and Olga Bays. In October - November, ice cover mainly develops within bays and bays, and from late November - early December, ice begins to form in the open sea.
At the end of December, ice formation in coastal and open sea areas extends to Peter the Great Bay.
Fast ice is not widespread in the Sea of Japan. It forms first in the bays of De-Kastri, Sovetskaya Gavan and Olga; in the bays of Peter the Great Bay and Posyet it appears after about a month.
Every year, only the northern bays of the mainland coast freeze completely. South of Sovetskaya Gavan, the fast ice in the bays is unstable and can break up repeatedly during the winter. In the western part of the sea, floating and stationary ice appears earlier than in the eastern part; it is more stable. This is explained by the fact that the western part of the sea in winter is under the predominant influence of cold and dry air masses spreading from the mainland. In the east of the sea, the influence of these masses weakens significantly, and at the same time the role of warm and humid marine air masses increases. The ice cover reaches its greatest development around mid-February. From February to May, conditions favorable for ice melting (in situ) are created throughout the sea. In the eastern part of the sea, ice melting begins earlier and occurs more intensely than at the same latitudes in the west.
Ice cover in the Sea of Japan varies significantly from year to year. There may be cases when the ice cover in one winter is 2 times or more greater than the ice cover in another.
The fish population of the Sea of Japan includes 615 species. The main commercial species of the southern part of the sea include sardine, anchovy, mackerel, and horse mackerel. In the northern regions, the main fish caught are mussels, flounder, herring, greenling and salmon. In summer, tuna, hammerfish, and saury penetrate into the northern part of the sea. The leading place in the species composition of fish catches is occupied by pollock, sardine and anchovy.
B.S. Zalogin, A.N. Kosarev "Sea" 1999