Why is the Sea of ​​Japan called that? The nature of the Japanese Sea and its economic importance

The Sea of ​​Japan is considered one of the deepest bodies of water in the world. Its waters spread between Eurasia, Sakhalin and the Japanese islands. WITH geographical point From a perspective, this water area is considered to be a marginal oceanic sea. In Korea, it is customary to call this body of water the East or East Korean Sea.

Shores of the Sea of ​​Japan

The scale of the Sea of ​​Japan is confirmed by its indicators. The total size of the reservoir exceeds 1000 km 2, and the greatest depth reaches almost 4000 meters. The border between the Sea of ​​Japan and Pacific Ocean are Japanese islands, and the reservoir is fenced from the Sea of ​​Okhotsk by the island of Sakhalin. The Korean Peninsula is located between the Yellow and Sea of ​​Japan.

The waters of this sea wash the borders of Japan, Korea, North Korea and Russia.

The northern half of the water area freezes in the winter season, but in the south this does not happen due to the heat brought by the Kuroshio Current. Coastline quite simple and flat, especially near Sakhalin. There are several small islands in the sea, for example, Okushiri, Rebun, Sado. Several mountain rivers also flow into the water area.

Cities of the Sea of ​​Japan

As already mentioned, on the territory of the sea itself there are no large islands, which would have important settlements or ports. The main part of the small land areas is located in the eastern waters near the coast. Russian borders The Sea of ​​Japan touches the Primorsky Territory, the southeastern part Khabarovsk Territory and southwestern regions of Sakhalin. The main ports of the Sea of ​​Japan can be considered:

• Nakhodka;
• Vladivostok;
• Oriental;
• Alexandrovsk-Sakhalinsky;
• Niigata;
• Tsuruga;
• Wonsan;
• Hungnam;
• Chongjin;
• Busan.

Fisheries of the Sea of ​​Japan

The waters of this area are considered one of the richest in terms of diversity. fish species. Huge quantities of fish are caught here throughout the year. Here you can find sardines, flounder, mussels, mackerel, tuna, saury, horse mackerel. As for minerals, there are not too many of them. In particular, a gas field was discovered, but no one is developing it. On the shore sea ​​of ​​japan There is a wide transport network, a fishing fleet and quite a few industrial enterprises, due to which the waters are constantly polluted.

IN Lately in the Sea of ​​Japan, the production of kelp, crabs, sea ​​urchins and scallops. The tourism industry is also growing.

Part of the Pacific Ocean basin and separated from it by Sakhalin and the Japanese Islands, the Sea of ​​Japan splashes off the coasts of Russia, Japan, China and Korea. The climatic conditions here are harsh. In the northern and western parts, ice appears already by the third ten days of November, and in some years the ice formed by the 20th of October. Temperatures in these areas can drop to -20 degrees Celsius. Ice melting begins in March and continues until the end of April. There were years when the sea surface was completely cleared of ice cover only in June.

However, in summer the Sea of ​​Japan in its southern borders pleases with a water temperature of +27 (even higher than in the Aegean Sea!). In the northern part, the water temperature is about +20 degrees, the same as in May in the south of Greece. A characteristic feature of the Sea of ​​Japan is its extremely unstable weather. In the morning the sun can shine brightly, and by lunchtime a strong wind rises and a storm with thunderstorms begins. This happens especially often in the fall. Then during a storm the wave can reach 10-12 meters in height.

The Sea of ​​Japan is rich in fish. Mackerel, flounder, herring, saury, and cod are caught here. But the most popular, of course, is pollock. During spawning, coastal waters literally boil with a huge amount of this fish. Shrimp is also produced here and has become very popular in last years seaweed, or rather, in addition, in the Sea of ​​Japan you can find squid and octopus, which can be found weighing up to 50 kilograms. And the huge eels found here, also called herring kings, were in years past mistaken for underwater monsters.

Holidays on the Sea of ​​Japan will appeal more to those who are not looking for noisy entertainment. The beauty of the reefs and crystal clear waters are ideal for snorkeling enthusiasts. Equipment here can be obtained from special diving centers. They also give it out at many tourist centers.

The only thing divers need to take into account is that the water temperature drops sharply with depth. In the northern waters, already at a depth of 50 meters it reaches only +4 degrees Celsius. In the southern part, the temperature reaches this level at a depth of approximately 200 meters. And a little deeper it equals zero.

Those who choose the Sea of ​​Japan for vacation can not only go diving, but also make interesting forays into the Ussuri taiga. It keeps a lot of secrets and mysteries, so you won’t be bored here. Just look at the footprint of a giant left in a stone. Its length is incredible for our perception - it is one and a half meters! The Dragon Park is also of great interest. Locals We are sure that the unusual accumulation of huge boulders was once created by aliens. On sea ​​coast Near the city of Nakhodka there are two hills called Brother and Sister. According to legend, they were made by the Titans as a gate through which the Prince of Light would one day come to Earth. For lovers of everything mysterious and unusual, a holiday on the Sea of ​​Japan will seem like paradise. And the exotic beauty of these places will remain in the memory for a long time.

The Inland Sea of ​​Japan splashes between Kyushu and Shikoku. It is small, only 18 thousand square kilometers, but is the most important transport artery between these islands. On its banks rise Hiroshima, Fukuyama, Osaka, Niihama and other major industrial centers of Japan. This sea is considered warm. The water temperature here, even in the winter months, never falls below +16 degrees Celsius, and in the summer it rises to +27. Tourism on this small sea is very well developed. Every year thousands of people from all over the world come here to admire the magnificent landscapes, visit ancient samurai shrines, and get acquainted with the original Japanese culture.

Refers to the Pacific Ocean, or more precisely, to its western part. Located near the island of Sakhalin, between Asia and Japan. It washes South and North Korea, Japan and the Russian Federation.

Although the reservoir belongs to the ocean basin, it is well isolated from it. This affects both the salinity of the Sea of ​​Japan and its fauna. The overall balance of water is regulated by outflows and inflows through straits. It practically does not participate in water exchange (small contribution: 1%).

It is connected to other bodies of water and the Pacific Ocean by 4 straits (Tsushima, Soyu, Mamaia, Tsugaru). is about 1062 km 2. The average depth of the Sea of ​​Japan is 1753 m, the greatest is 3742 m. It is difficult to freeze, only it Northern part In winter it is covered with ice.

The hydronym is generally accepted, but is disputed by the Korean powers. They claim that the name was literally imposed by the Japanese side on the whole world. IN South Korea it is called East Sea, and the North uses the name Korean East Sea.

The problems of the Sea of ​​Japan are directly related to ecology. They could be called typical, if not for the fact that the reservoir washes several states at once. They have different policies on the sea, so the influence from people also varies. Among the main problems are the following:

• industrial mining;
• release of radioactive substances and petroleum products;
• oil spills.

Climatic conditions

According to glaciation, the Sea of ​​Japan is divided into three parts:

• Tatarsky is against;
• Peter the Great Bay;
• area from Povorotny Cape to Belkin.

As already described above, ice is always localized in part of a given strait and bay. In other places it practically does not form (if you do not take into account the bays and northwestern waters).

An interesting fact is that ice initially appears in places where there is fresh water Sea of ​​Japan, and only then does it spread to other parts of the reservoir.

Glaciation lasts in the south for about 80 days, in the north - 170 days; in Peter the Great Bay - 120 days.

If winter is not characterized by severe frosts, then areas are covered with ice in early to late November; If the temperature drops to critical levels, then freezing occurs earlier.

By February, the formation of the cover stops. At this moment, the Tartary Strait is covered by about 50%, and the Peter the Great Gulf by 55%.

Thawing often begins in March. The depth of the Sea of ​​Japan facilitates the rapid process of getting rid of ice. It could start at the end of April. If temperatures remain low, thawing begins in early June. First, parts of the Peter the Great Bay are “opened,” in particular, its open waters, and the coast of the Golden Cape. While the ice in the Tatar Strait begins to retreat, in its eastern part it thaws.

Resources of the Sea of ​​Japan

Biological resources are used by humans to the maximum extent. Fishing is developed near the shelf. Herring, tuna and sardines are considered valuable fish species. In the central regions, squid are caught, in the north and southwest - salmon. Algae from the Sea of ​​Japan also play an important role.

Flora and fauna

The biological resources of the Sea of ​​Japan in different parts have their own characteristic features. Due to the climatic conditions in the north and northwest, nature has moderate characteristics; in the south, the faunal complex predominates. Near Far East There are plants and animals native to warm-water and temperate climates. Here you can see squid and octopus. In addition to them, there are brown algae, sea urchins, stars, shrimp and crabs. Still, the resources of the Sea of ​​Japan are bursting with diversity. There are few places where you can find red sea squirts. Scallops, ruffs and dogs are common.

Sea problems

The main problem is the consumption of sea resources due to the constant fishing of fish and crabs, algae, scallops, and sea urchins. Along with state fleets, poaching is flourishing. The overuse of fish and shellfish production leads to the constant extinction of some species of marine animals.

In addition, careless fishing can lead to death. Due to fuel and lubricating waste, wastewater and petroleum products, fish die, mutate or become contaminated, which poses a great danger to consumers.

Several years ago, this problem was overcome thanks to coherent actions and agreements between the Russian Federation and Japan.

Ports of companies, enterprises and settlements- the main source of water pollution containing chlorine, oil, mercury, nitrogen and other hazardous substances. Due to the high concentration of these substances, blue-green algae develop. Because of them, there is a danger of hydrogen sulfide contamination.

Tides

Complex tides are characteristic of the Sea of ​​Japan. Their cyclical nature different areas is significantly different. The semi-diurnal one is found near the Korea Strait and near the Tatar Strait. Daytime tides are characteristic of areas adjacent to the coast Russian Federation, the Republic of Korea and the DPRK, as well as near Hokkaido and Honshu (Japan). Near Peter the Great Bay, the tides are mixed.

Tidal levels are low: from 1 to 3 meters. In some areas the amplitude varies from 2.2 to 2.7 m.

Seasonal variations are also not uncommon. They are observed most often in summer; in winter there are fewer of them. The water level is also affected by the nature of the wind and its strength. Why do the resources of the Sea of ​​Japan depend so much?

Transparency

Throughout the entire length of the sea, the water is of different colors: from blue to blue with a green tint. As a rule, transparency remains at a depth of up to 10 m. The waters of the Sea of ​​Japan have a lot of oxygen, which contributes to the development of resources. Phytoplankton is more common in the north and west of the reservoir. On the surface of the water, the oxygen concentration reaches almost 95%, but this figure gradually decreases with depth, and by 3 thousand meters it is equal to 70%.

The nature of our planet is beautiful and amazing. You can admire its beauty endlessly.

One of the most attractive, unknown, unpredictable elements for humans at all times has been water. Among the diversity of rivers, seas and oceans interesting object to study is the Sea of ​​Japan, whose resources belong to several countries and play a large role in their development.

Description

This sea belongs to the Pacific Ocean basin. Along with Bering and Okhotsk, it is considered one of the largest and deep seas Russia. It is of great importance in transport and cargo transportation and is a source of mineral resources. The Sea of ​​Japan is also different high level production of commercial fish species.

Its area stretches over an area of ​​approximately 1,100 square kilometers, and its volume is 1,700 cubic kilometers. The average depth of the Sea of ​​Japan is 1550 meters, while the greatest depth is more than 3500 meters.

The sea is connected to other seas and the ocean by straits. Nevelsky connects it with the Sea of ​​Okhotsk, Korean with East China. Shimonoseki divides the Sea of ​​Japan and the Inland Sea of ​​Japan, and is also connected to the Pacific Ocean through the Sangar Strait.

Location

The Sea of ​​Japan lies between the Asian mainland and the Korean Peninsula. It washes the land of several countries: Russia, Japan, North Korea, and the Republic of Korea.

A characteristic of the Sea of ​​Japan is also the presence small islands, such as Popov, Okushiri, Russian, Oshima, Putyatin, Sado and others. The cluster of islands is mainly concentrated in the eastern part.

The waters form bays, such as Sovetskaya Gavan, Ishikari, and Peter the Great. And also capes, the most famous of which are Cape Lazarev, Korsakov, Soya.

The Sea of ​​Japan has many shipping ports. Some of the most significant are Vladivostok, Nakhodka, Aleksandrovsk-Sakhalinsky, Tsuruga, Chongjin and others. They organize the transportation of goods not only across the Sea of ​​Japan, but also beyond its borders.

Climate

The weather characteristics of the Sea of ​​Japan are temperate and subtropical climate, stable winds.

Its geographical location and large extent divided it into two climatic parts: the northwestern and southeastern zone.

The water temperature in different parts depends on the circulation of streams, heat exchange with the atmosphere, the time of year, and also on the depth of the Sea of ​​Japan. In the northern and western parts, the water and air temperatures are much lower due to the influence of the cold Sea of ​​Okhotsk. The eastern and southern zones are affected by water and air masses, coming from the Pacific Ocean, so temperatures are much higher.

In winter, the sea is prone to hurricanes and storms, which can last for several days. The autumn period is typical strong winds, which form high, powerful waves. IN summer time During the year, stable warm weather prevails in both climatic zones.

Water characteristics

During the winter season, the water temperature in different areas varies greatly. The northern part is characterized by an icy surface surface, while in the southern part the approximate temperature is 15 degrees.

In summer, the northern waters of the Sea of ​​Japan warm up to 20 degrees, the southern ones - up to 27.

The water balance consists of two important components: the amount of precipitation, evaporation of water from the surface, and water exchange, which is carried out through straits.

Salinity consists of the resources of the Sea of ​​Japan, water exchange with other seas, the Pacific Ocean, the amount of precipitation, ice melting, time of year, and some other factors. The average salinity is about 35 ppm.

The transparency of water depends on its temperature. In winter it is higher than in the warm period of the year, so in the northern part the density is always higher than in the southern part. According to this principle, the oxygen saturation of water is distributed.

Development of transport routes

The role of the Sea of ​​Japan in organizing cargo transportation is very great both for Russia and for other countries.

Maritime transport and cargo transportation is characterized by high development, which has for Russia great importance. The Trans-Siberian Railway ends in the city of Vladivostok. railway track. Here the railway is unloaded and loaded maritime transport. In the future according to sea ​​routes passengers and cargo are sent to other ports in different countries.

Fishing

The fishery resources of the Sea of ​​Japan are highly productive and diverse, including a large number of fish species. Its waters accommodate more than 3,000 inhabitants. Their population depends on climate conditions in different areas.

In the warm southeastern part, fishing for mackerel, saury, sardines, mackerel, anchovies, flounder, and some other types of fish is common. You can also find a large number of octopuses here. Squid and crabs live in the central regions. In the northwest, salmon, pollock, cod, and herring are caught. The sea also abounds in sea cucumbers, mussels, and oysters.

Recently, production has been actively developing, where crayfish and sea urchins are bred, as well as algae, seaweed, kelp, mollusks, and scallops. These aquacultures are also resources of the Sea of ​​Japan.

In addition to commercial species, the Sea of ​​Japan is rich in other inhabitants. Here you can find seahorses, dolphins, whales, seals, sperm whales, beluga whales, small species of sharks and other types of marine life.

Ecology

Like the resources of the Sea of ​​Japan, ecological problems require separate study. The impact of population life on the environment differs in different areas.

The main source of pollution is the discharge of industrial and domestic wastewater. The greatest negative impact comes from the release of radioactive substances, petroleum products, chemical and coal industries, and metalworking. Waste from various industries flows into the waters of the Sea of ​​Japan.

Oil production and transportation is associated with great risks for environment. If there is a leak, the oil stain is quite difficult to remove. It causes enormous damage to the ecology of the sea and its inhabitants.

Transport waste from numerous ports and sewage from cities that flow into the sea also cause considerable harm.

Studies of the water of the Sea of ​​Japan show quite high pollution. The composition contains many chemical elements discharged by industries, as well as heavy metals, phenol, zinc, copper, lead, mercury, ammonium nitrogen compounds and other substances. All this contributes to enormous environmental pollution.

The leaders of the countries with which the sea borders are taking targeted operational and preventive actions in order to preserve unique nature, cleanliness and its inhabitants. It is necessary to control, suppress, and severely punish cases of releases of chemical and oil waste into waters. Enterprises and sewage systems must be equipped with purification filters.

These control measures will be able to prevent environmental pollution, protect numerous inhabitants from death, and also preserve human health.

The Sea of ​​Japan is one of the most valuable resources that must not only be actively used, but also protected from the negative consequences of human activity.

The information provided will help to assess the resources of the Sea of ​​Japan, study its characteristics, recognize its inhabitants, and clarify environmental aspects.

The study of this sea has been going on for a long time. Nevertheless, many questions and problems remain that require research and targeted measures.

The Sea of ​​Japan is a marginal sea of ​​the Pacific Ocean and is limited by the coasts of Japan, Russia and Korea. The Sea of ​​Japan is connected 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 Sea of ​​Okhotsk. The area of ​​the Sea of ​​Japan is 980,000 km2, average depth 1361 m. The northern border of the Sea of ​​Japan runs along 51°45" N latitude (from Cape Tyk on Sakhalin to Cape Yuzhny on the mainland). Southern border goes from Kyushu Island to the Goto Islands and from there to Korea [Cape Kolcholkap (Izgunova)]

The Sea of ​​Japan has an almost elliptical shape with the major axis in the direction from southwest to northeast. 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 Kyushu Island), Ulleungdo and Takashima east coast Korea, Oki and Sado off the west coast of Honshu Island (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. w. into two parts: northern and southern.

The northern part has a relatively flat bottom topography and is characterized by an overall smooth slope. Maximum depth(4224 m) is observed in the area of ​​43°00"N, 137°39"E. d.
The bottom topography 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
jars separated by deep grooves. This is the Yamato Bank, opened in 1924, in the area of ​​39°N, 135°E. etc., and the Shunpu Bank (also called the Northern Yamato Bank), opened in 1930 and located approximately 40° N. latitude, 134° east. d. The smallest depths of the first and second banks are 285 and 435 m, respectively. A depression with a depth of more than 3000 m was discovered between the Yamato Bank and the island of Honshu.

Hydrological regime

Water masses, temperature and salinity. The Sea of ​​Japan can be divided into two sectors: warm (from Japan) and cold (from Korea and Russia (Primorsky Territory). The boundary between the sectors is the polar front, running approximately along the parallel of 38-40 ° N, i.e. almost along the same latitudes along which the polar front passes in the Pacific Ocean east of Japan.

Water masses

The Sea of ​​Japan can be divided into surface, intermediate and deep. The surface water mass occupies a layer up to approximately 25 m and in summer is separated from the underlying waters 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 when ice melts from early summer to autumn , and the waters of Siberian rivers.

The surface water mass exhibits the largest fluctuations in temperature and salinity depending on the season and 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 island. Hokkaido. In the coastal areas of Korea and Primorye, changes in salinity are small (33.7-34 ppm). The intermediate water mass, which lies below the surface water in the warm sector of the Sea of ​​Japan, has high temperature and salinity. It is formed in the intermediate layers of Kuroshio west of Kyushu Island and enters the Sea of ​​Japan from there during the period of early winter to early summer.

However, based on 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 vertical temperature - 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 to the cold sector; 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 industrial. in the cold. The highest salinity values ​​are observed here at all depths - from the surface to the bottom.

The deep water mass, usually called 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 increases slightly due to adiabatic heating. At the same horizon, a decrease in oxygen content to a minimum is observed, and therefore it is more logical to consider waters above 1500 m as deep, and below 1500 m as bottom. Compared to 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 the 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 increases to approximately 34.0 ppm.

Sometimes the low-salinity surface waters of the cold sector (1-4° C, 33.9 ppm) wedge into the polar front and deepen in a southerly direction, going under the intermediate waters of the warm sector. This phenomenon is similar to the penetration of subarctic intermediate water below the warm Kuroshio layer in the Pacific Ocean in the area north of Japan.

In spring and summer, the salinity of warm waters from the East China Sea and cold waters east of Korea decreases due to precipitation and melting ice. These less saline waters mix with surrounding waters and the overall salinity of the surface waters of the Sea of ​​Japan decreases. Additionally, 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 clearly defined upper thermocline layer that separates the surface waters from the underlying intermediate waters. The upper thermocline layer is located in summer season at a depth of 25 m. In autumn, heat is transferred from the sea surface to the atmosphere. Due to mixing with underlying water masses, the temperature of surface waters decreases and their salinity increases. The resulting intense convection leads to a deepening of the upper thermocline layer to 25–50 m in September and 50–100 m in November. In autumn, intermediate waters of the warm sector are characterized by a decrease in salinity due to the influx of waters of 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 upper thermocline layer disappears completely due to the mixing of overlying and underlying waters. Therefore, in autumn and spring there is only an upper homogeneous layer of water and an underlying cold layer, separated by a layer of 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 off the coast of the island 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 surface layer temperature off the Korean coast 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 large depths, the waters of the Tsushima Current are greatly cooled as they move north.

The waters of the Sea of ​​Japan are characterized by exceptionally high levels of dissolved oxygen, partly due to the abundance of phytoplankton. The oxygen content at almost all horizons here is about 6 cm3/l or more. Particularly high oxygen content is observed in surface and intermediate waters, with a maximum value at the horizon of 200 m (8 cm3/l). These values ​​are much higher than at the same and lower horizons 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. north coast In Korea it is 110% and even higher. In deep waters there is a very high oxygen content right down to the bottom.

Color and transparency

The color of the water of the Sea of ​​Japan (according to the color scale) in the warm sector is bluer than in the cold sector, corresponding to the region of 36-38° N. latitude, 133-136° east. etc. 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. The northern part of the Sea of ​​Japan shows a greenish color sea ​​water. Transparency (by the white disk) in the Tsushima Current region is more than 25 m. In the cold sector it sometimes drops to 10 m.

Currents of the Sea of ​​Japan

The main current of the Sea of ​​Japan is the Tsushima Current, which originates in the East China Sea. It is strengthened mainly by the branch of the Kuroshio Current, going to the SOUTHWEST of the island. Kyushu, as well as partially by coastal runoff from China. The Tsushima Current contains surface and intermediate water masses. The current enters the Sea of ​​Japan through the Korea Strait and is directed along the north west bank Japan. There, a branch of the warm current, called the East Korean Current, separates from it, which goes in the north, to the coast of Korea, to the Korean Gulf and Ulleungdo Island, then turns to the SE and connects with the main flow.

The Tsushima Current, about 200 km wide, washes the shores of Japan and goes further to the NE at a speed of 0.5 to 1.0 knots. Then it divides into two branches - the warm Sangar Current and the warm La Perouse Current, which respectively exit 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 east and go, respectively, close to eastern shore the island of Honshu and the northern coast of Hokkaido.

There are three cold currents in the Sea of ​​Japan: the Liman current, moving at low speed to the southwest in the area north of the Primorsky Territory, the North Korean current, going south in the Vladivostok area to eastern Korea, and the Primorsky current, or the 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, contain clearly defined layers of surface and intermediate water masses. There is a clear boundary of the “polar” front between the warm and cold currents.

Because the Tsushima Current contains surface and intermediate water masses that 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 speed is almost constant to a depth of 25 m, 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 flow rate of the Kuroshio Current.

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 Korean Current, which is the strongest, has a speed of 0.5 knots. The width of this current is 100 km, thickness - 50 m. In general, cold currents in the Sea of ​​Japan are much weaker than warm ones. average speed The Tsushima Current passing through the Korean Strait is less in winter, and in summer it increases to 1.5 knots (in August). For the Tsushima Current, interannual changes are also observed, with a clear period of 7 years being distinguished. The flow of water into the Sea of ​​Japan mainly occurs through the Korea Strait, since the inflow through the Tartary Strait is very insignificant. The flow of water from the Sea of ​​Japan occurs through the Tsugaru (Sangara) and La Perouse Straits.

Tides and tidal currents

Tides are low for the Sea of ​​Japan. While off the coast of the Pacific Ocean the tide is 1-2 m, in the Sea of ​​Japan it reaches only 0.2 m. Slightly higher values ​​are observed off the coast of the Primorsky Territory - up to 0.4-0.5 m. In the Korean and Tatar Territories In the straits, the tide increases, reaching more than 2 m in some places.

Tidal waves propagate at right angles to these cotidal lines. 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 amphidromic point is located in the Korea Strait Since the total area cross section Since the La Perouse and Tsugaru straits are only 1/8 of the cross-sectional area of ​​the Korea Strait, and the cross-section of the Tartary Strait is generally insignificant, the tidal wave comes here from the East China Sea mainly through the Eastern 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 eastward Tsushima Current sometimes reaches 2.8 knots. In the Tsugaru (Soigarsky) Strait, a tidal current of the diurnal type predominates, but the magnitude of the semidiurnal tide is greater here.

There is a clear diurnal inequality in tidal currents. 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 diurnal inequality here. In the La Perouse Strait, the current is directed mainly to the east; its speed sometimes exceeds 3.5 knots.

Ice Conditions

Freezing of the Sea of ​​Japan begins in mid-November in the area of ​​the Tatar Strait and in early December in the upper reaches of Peter the Great Bay. In mid-December, areas near the northern part of Primorsky Krai and Peter the Great Bay freeze. In mid-December, ice appears in the coastal areas of Primorsky Krai. In January, the area of ​​ice cover increases further from the coast to the side open sea. With the formation of ice, navigation in these areas naturally becomes difficult or stops. The freezing of the northern part of the Sea of ​​Japan is somewhat delayed: it begins in early to mid-February.

Ice melting begins in areas furthest 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 in Vladivostok resumes. Last Ice in the Tatar Strait is observed in early to mid-May. The period of ice cover along the coast of the Primorsky Territory is 120 days, and near the De-Kastri harbor in the Strait of Tartary - 201 days. Along the northern coast of the DPRK large quantity no ice is observed. On 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 Sea of ​​Japan basin are characterized by many submarine canyons. On the mainland side, these canyons stretch to depths of more than 2000 m, and on the side of the Japanese Islands only to 800 m. The mainland shoals of the Sea of ​​Japan are poorly developed, the edge runs at a depth of 140 m on the mainland side and at a depth of more than 200 m. Yamato Bank and other banks The Sea of ​​Japan is composed of bedrock consisting of Precambrian granites and other Paleozoic rocks and overlying Neogene igneous and sedimentary rocks. According to paleogeographic studies, the southern part of the modern Sea of ​​Japan was probably dry land in the Paleozoic and Mesozoic and during most of the Paleogene. It follows from this that the Sea of ​​Japan was formed during the Neogene and early Quaternary periods. The absence of a granite layer in the earth's crust of the northern part of the Sea of ​​Japan indicates the transformation of the granite layer into a basalt layer due to basification, accompanied by subsidence of the earth's crust. The presence of “new” oceanic crust here can be explained by the stretching of continents accompanying the general expansion of the Earth (Egayed’s theory).

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

The Sea of ​​Japan currently has a connection with the Pacific Ocean and the surrounding marginal seas through the Korean, Tsugaru (Saigarsky), La Perouse and Tatar straits. However, the formation of these four straits occurred in very recent times. geological periods. The oldest strait is the Tsugaru (Sangara) Strait; it already existed during the Wisconsinian glaciation, although it may have been filled with ice several times after that 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 southern elephants to the Japanese islands took place; 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