Brief information about the Sea of ​​Japan. Sea of ​​Japan, map

The main ports of the Sea of ​​Japan are Vladivostok, Nakhodka, Vostochny, Sovetskaya Gavan, Vanino, Aleksandrovsk-Sakhalinsky, Kholmsk, Niigata, Tsuruga, Maizuru, Wonsan, Hungnam, Chongjin and Busan, through which not only various cargoes are delivered, but also fish are caught, crabs, trepangs, algae, sea ​​urchins, scallops and much more.

The Sea of ​​Japan has a temperate and monsoonal climate, with its northern and parts much cooler than the southern and eastern parts. The Sea of ​​​​Japan is also rich in typhoons caused by hurricane winds, which often fall on the coast of countries washed by the sea.

The degree of salinity of the Sea of ​​Japan is somewhat lower than that of other waters of the World Ocean - about 33.7-34.3%.

Which islands are located in the Sea of ​​Japan

In total, over 3 thousand islands of various sizes are located in the Sea of ​​Japan, most of which belong to the Japanese archipelago.

The main islands of the sea are Hokkaido (an area of ​​83.4 thousand square kilometers, on which 5.5 million people lived in 2010), Honshu (227.969 thousand square kilometers), Shikoku (18.8 thousand square kilometers and 4.141 million people as of 2005) and Kyushu (40.6 thousand square kilometers and 12 million people living on the island by the end of 2010).

To the islands of the so-called Inland Sea of ​​Japan, connecting with Pacific Ocean through the four straits of Hayasui, Bungo, Kii and Naruto, are the following - Kasado, Hime, Heigun, Yashiro, Itsukushima (area of ​​30.39 square kilometers and 2 thousand inhabitants), Nishinomi, Etajima, Kurahashi, Innoshima, Teshima, Sedo and Awaji (592.17 thousand square kilometers and 157 thousand people as of 2005).

It is quite difficult to list the remaining 3 thousand relatively small islands of the Sea of ​​Japan, but geographers divide them into several groups:
- small islands along the island of Hokkaido;
- along the island of Honshu;
- the islands of the Korea Strait (connects the Japan and East China Seas with a length of 324 kilometers);
- islands of the East China Sea;
- along the island of Shikoku;
- along Kyushu;
- the Ryukyu archipelago (another name is the Likey Islands, a total of 96 large and small ones) also includes several island subgroups - Osumi, Tokara, Amami, Okinawa, Sakishima, Yaeyama, Miyako, Senkaku, Daito and the Borodin Islands.

There are also several artificial islands in the Sea of ​​Japan. One of them - Dejima - was created in the form of a century and served as a port for Dutch ships from the 17th to the middle of the 19th century.

The Sea of ​​Japan lies between the mainland Asia, the peninsula of Korea, about. 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 of Cape Sushcheva - Cape Tyk on Sakhalin. In the Laperouse Strait, the boundary line is Cape Soya - Cape Crillon. In the Sangar Strait, the border runs along the line of Cape Syria - Cape Estan, and in the Korea Strait - along the line of Cape Nomo (Kyushu Island) - Cape Fukae (Goto Island) - about. Jeju - Korean Peninsula.

The Sea of ​​Japan is one of the largest and deepest seas in the world. Its area is 1062 km 2, volume - 1631 thousand km 3, average depth - 1536 m, maximum depth - 3699 m. This is a marginal oceanic sea.

There are no large islands in the Sea of ​​Japan. Of the smaller ones, the most significant are the islands of Moneron, Rishiri, Okushiri, Ojima, Sado, Okinoshima, Ullyndo, Askold, Russian, 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 comparatively slightly indented. The most simple in outline is the coast of Sakhalin, the coasts of Primorye and the Japanese Islands are more sinuous. Large bays of the mainland coast include De-Kastri, Sovetskaya Gavan, Vladimir, Olga, Peter the Great, Posyet, Korean, on about. Hokkaido - Ishikari, on about. Honshu - Toyama and Wakasa.

Landscapes of the Sea of ​​Japan

Coastal boundaries cut through the straits that connect the Sea of ​​Japan with the Pacific Ocean, the Sea of ​​Okhotsk and the East China Sea. The straits are different in length, width and, most importantly, in depth, which determines the nature of the 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 maximum depths are, about 400 m. The Nevelskoy and Laperouse straits connect the Sea of ​​Japan and the Sea of ​​Okhotsk. The Korean Strait, divided by the islands of Jejudo, Tsushima and Ikizuki into the western (Broughton Passage with the greatest depth of about 12.5 m) and the eastern (Krusenstern Passage with the greatest depth of about 110 m) parts, connects the Sea of ​​Japan and the East China Sea. 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, at 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.

Diverse in structure and external forms, the coast of the Sea of ​​Japan in different areas belongs to different morphometric types of coasts. Mostly these are abrasion, mostly little-changed, coasts. To a lesser extent, the Sea of ​​Japan is characterized by accumulative shores. This sea is surrounded by mostly mountainous shores. In places, single rocks rise out of the water - kekurs - characteristic formations of the Sea of ​​Japan coast. Low-lying shores are found only in certain parts of the coast.

Bottom relief

Bottom relief and currents of the Sea of ​​Japan

According to the nature of the bottom topography, the Sea of ​​Japan is divided into three parts: the northern one - north of 44 ° N, the central one - between 40 and 44 ° N. and southern - south of 40 ° N.L.

The northern part of the sea is like a wide trough, gradually rising and narrowing towards the north. Its bottom in the direction from north to south forms three steps, which are separated from one another by clearly defined ledges. The northern step is at a depth of 900-1400 m, the middle step is at a depth of 1700-2000 m, and the southern step is at a depth of 2300-2600 m. The surfaces of the steps are slightly inclined to the south.

The coastal shoal of Primorye in the northern part of the sea is approximately 20 to 50 km long, the edge of the shoal is located at a depth of about 200 m.

The surfaces of the northern and middle steps of the central trough are more or less level. The relief of the southern step is significantly complicated by numerous individual uplifts up to 500 m high. Here, on the edge of the southern step, at a latitude of 44 °, there is a vast Vityaz upland with a minimum depth above it of 1086 m.

The southern step of the northern part of the Sea of ​​Japan breaks off as a steep ledge to the bottom of the central basin. The steepness of the ledge is on average 10-12°, in some places 25-30°, and the height is approximately 800-900 m.

The central part of the sea is a deep closed basin, slightly elongated in an east-northeast direction. From the west, north, and east, it is bounded by the steep slopes of the mountain structures of Primorye, the Korean Peninsula, the islands of Hokkaido and Honshu, descending into the sea, and from the south, by the slopes of the underwater height of Yamato.

In the central part of the sea, coastal shallows are very poorly developed. A relatively wide shoal is located only in the region of southern Primorye. The edge of the shoal in the central part of the sea is very clearly expressed throughout its length. The bottom of the basin, located at a depth of about 3500 m, is leveled in contrast to the complexly dissected surrounding slopes. On the surface of this plain, separate hills are noted. Approximately in the center of the basin there is an underwater ridge stretched from north to south with a height of up to 2300 m. The southern part of the sea has a very complex relief, since in this area there are marginal parts of large mountain systems - the Kuril-Kamchatka, Japanese and Ryu-Kyu. Here is located the vast Yamato Upland, which consists of two ridges elongated in the east-north-east direction with a closed basin located between them. From the south, the Yamato Rise is adjoined by a wide underwater ridge of approximately meridional strike.

In many areas of the southern part of the sea, the structure of the underwater slope is complicated by the presence of underwater ridges. On the underwater slope of the Korean Peninsula, wide underwater valleys can be traced between the ridges. The continental shelf almost throughout its length has a width of no more than 40 km. In the area of ​​the Korea Strait, the shoals of the Korean Peninsula and about. Honshu merge and form shallow water with depths of no more than 150 m.

Climate

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 atmospheric pressure gradients. In this regard, strong northwestern winds with speeds of 12-15 m/s and more dominate the sea. Local conditions change the wind conditions. In some areas, under the influence of the relief of the coasts, a large frequency of northern winds is noted, in others, calms are often observed. On the southeast coast, the regularity of the monsoon is violated, west and northwest winds prevail here.

During the cold season, continental cyclones enter the Sea of ​​Japan. They cause strong storms, and sometimes severe hurricanes that last for 2-3 days. In early autumn (September), tropical typhoon cyclones sweep over the sea, accompanied by hurricane-force 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 effects of the Hawaiian High and, to a lesser extent, by the depression that forms over Eastern Siberia in summer. In this regard, south and south-west winds prevail over the sea. However, pressure gradients between high and low pressure areas are relatively small, so the average wind speed is 2-7 m/s. A significant increase in wind is associated with the release of oceanic, less often continental cyclones to the sea. In summer and early autumn (July-October), the number (with a maximum in September) of typhoons increases over the sea, which cause 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 parts of the sea. They are mainly due to the peculiarities of the orography of the coasts and are most noticeable in the coastal zone.

In the Far Eastern seas

The summer monsoon brings with it warm and humid air. The average monthly temperature of the warmest month - August - in the northern part of the sea is about 15 °, and in the southern regions about 25 °. Significant cooling is observed in the northwestern part of the sea with cold air inflows brought by continental cyclones. Cloudy weather with frequent fogs prevails in spring and summer.

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. The continental runoff into the Sea of ​​Japan is approximately 210 km 3 /year and is fairly evenly distributed throughout the year. Only in July the river runoff slightly increases.

Geographical position, outlines of the basin of the sea, separated from the Pacific Ocean and adjacent seas by high thresholds in the straits, pronounced monsoons, water exchange through the straits only in upper layers- the main factors in the formation of the hydrological conditions of the Sea of ​​Japan.

The Sea of ​​Japan receives a lot of heat from the sun. However, the total heat consumption for effective radiation and evaporation exceeds the solar heat input, therefore, as a result of the processes occurring at the water-air interface, the sea annually loses heat. It is replenished due to the heat brought by the 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 inflow from outside.

Hydrology

Significant natural factors are the exchange of waters through the straits, the flow of precipitation to the sea surface and evaporation. The main inflow 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 goes through the Sangar Strait - 64% of the total flow; 34% flows out through the La Perouse and Korean straits. Only about 1% remains for the share of fresh components of the water balance (mainland runoff, precipitation). Thus, leading role in the water balance of the sea plays water exchange through the straits.

Scheme of water exchange through the straits in the Sea of ​​Japan

Features of the bottom topography, water exchange through the straits, 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 regions of the Pacific Ocean, but has its own characteristics, which have developed under the influence of local conditions.

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. Characteristics of surface water under the influence of climatic and hydrological factors change in time and space much more intensively.

Three water masses are distinguished in the Sea of ​​Japan: two in the surface zone: the surface Pacific Ocean, 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 distribution area gradually decrease, and approximately at about 48 ° N. latitude. due to a sharp decrease in depth, it wedges out in shallow water. In winter, when the Tsushima current weakens, the northern boundary of the Pacific waters is located approximately at 46-47 ° N.L.

Water temperature and salinity

The surface Pacific water is characterized by high values temperature (about 15-20°) and salinity (34-34.5‰). In this water mass, several layers are distinguished, the hydrological characteristics of which and the thickness change throughout the year:

the surface layer, where the temperature during the year varies from 10 to 25 °, and salinity - 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. Significant temperature, salinity and density gradients are noted in it;

the lower layer has a thickness of 100 to 150 m. During the year, its depth and distribution boundaries change; temperature varies from 4 to 12°, salinity - from 34 to 34.2‰. The lower intermediate layer has very small vertical gradients in temperature, salinity and density. It separates the surface Pacific water mass from the deep Sea of ​​Japan.

As we move north, the characteristics of the Pacific Ocean water gradually change under the influence of climatic factors as a result of its mixing with the underlying deep water of the Sea of ​​Japan. During cooling and desalination of Pacific water at latitudes 46-48 ° N.L. the surface water mass of the Sea of ​​Japan is formed. It is characterized by relatively low temperature (about 5-8°C on average) 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, in the surface Japanese-sea water biggest changes hydrological characteristics occur in the surface layer with a thickness of 10 to 150 m or more. The temperature here during the year varies 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 sink to depths due to the process of winter convection. Depth Japano stat changes sea ​​water very small vertically. The bulk of these waters has a temperature of 0.1-0.2° in winter, 0.3-0.5° in summer, salinity during the year 34.1-34.15‰.

Water temperature on the surface of the seas of Japan, Yellow, East China, South China, Philippine, Sulu, Sulawesi in summer

The features of the structure of the waters of the Sea of ​​Japan are well illustrated by the distribution of oceanological characteristics in it. Surface water temperatures generally rise from northwest to southeast.

In winter, the surface water temperature rises 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-pronounced water temperature contrast between the western and eastern parts of the sea, and in the south it is less pronounced than in the north and in the central part of the sea. So, 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 rapidly. At this time, the 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.

Near the western shores, the surface water temperature is 1-2° lower than near 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 until the horizons of 100-150 m, from which it gradually decreases with depth to about 2-4° at the horizons of 200-250 m, then it decreases very slowly - to 1-1, 5° at the horizons of 400-500 m, deeper the temperature decreases somewhat (to values ​​less than 1°) and remains approximately the same to the bottom.

In summer, in the north and north-west of the sea, a high surface temperature (18-20°) is observed in the 0-15 m layer, from here it sharply decreases with a depth of up to 4° at a 50 m horizon, then it decreases very slowly 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 rather smoothly with depth and at a horizon of 200 m it is approximately 6 °, from here it decreases somewhat faster and at the horizons of 250-260 m it is 1.5-2 °, then it decreases very slowly and at horizons 750-1500 m (in some areas on the horizons of 1000-1500 m) reaches a minimum equal to 0.04-0.14°, from here the temperature rises to the bottom up to 0.3°. The formation of an intermediate layer of minimum temperatures is presumably associated with the subsidence of waters in the northern part of the sea, which are cooled in severe winters. This layer is quite stable and is observed all year round.

Salinity on the surface of the Seas of Japan, Yellow, East China, South China, Philippine, Sulu, Sulawesi in summer

The average salinity of the Sea of ​​Japan, which is approximately 34.1‰, is somewhat 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 heavy precipitation causes some freshening. In most of the sea, salinity is 34.l‰. In springtime, in the north and northwest, surface water desalination occurs due to ice melting, while in other areas it is associated with increased precipitation. Relatively high (34.6-34.7‰) salinity remains in the south, where at this time the inflow of more saline waters flowing 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 about. 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 course of salinity is generally characterized by small changes in its values ​​with depth.

In winter, most of the sea has a uniform salinity from the surface to the bottom, equal to approximately 34.1‰. Only in coastal waters is there a weakly pronounced minimum of salinity in the surface horizons, below which the salinity slightly increases and remains almost the same to the bottom. At this time of the year, vertical salinity changes in most of the sea do not exceed 0.6-0.7‰, and in its central part do not reach

Spring-summer desalination of surface waters forms the main features of the summer vertical distribution of salinity.

In summer, the minimum salinity is observed on the surface as a result of a noticeable desalination of surface waters. In the subsurface layers, salinity increases with depth, and noticeable vertical salinity gradients are created. The maximum salinity at this time is observed at the horizons of 50-100 m in the northern regions and at the horizons of 500-1500 m in the south. Below these layers, salinity decreases somewhat and almost does not change 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.

Water circulation and currents

The density of the 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 parts.

In winter, the density on the surface is quite uniform throughout the sea, especially in its northwestern part.

In spring, the uniformity of surface density values ​​is disturbed due to different heating of the upper water layer.

In summer, the horizontal differences in surface density values ​​are greatest. They are especially significant in the area of ​​mixing of waters with different characteristics. In winter, the density is approximately the same from the surface to the bottom in the northwestern part of the sea. In the southeastern regions, the density slightly increases at the horizons of 50-100 m, deeper and to the bottom, it increases very slightly. The maximum density is observed in March.

In summer, in the northwest, the waters are noticeably stratified in density. It is small on the surface, rises sharply at the horizons of 50-100 m, and deeper to the bottom increases more smoothly. In the southwestern part of the sea, the density noticeably increases in the subsurface (up to 50 m) layers; at the 100-150 m horizons, it is quite uniform; below, the density slightly increases to the bottom. This transition occurs at the 150-200 m horizons in the northwest and at the 300-400 m horizons in the southeast of the sea.

In autumn, the density begins to level off, which means the transition to winter look density distribution with depth. The spring-summer density stratification determines a rather stable state of the waters of the Sea of ​​Japan, although it is expressed to different degrees in different regions. In accordance with this, more or less favorable conditions 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 the order of 20 m. In less stratified waters of the southern and southwestern regions, the wind mixes the upper layers to the horizons 25-30 m. In autumn, the stratification decreases, and the winds intensify, but at this time of the year, the thickness of the upper homogeneous layer increases due to density mixing.

Autumn-winter cooling and ice formation in the north 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 for a short time. With the onset of ice formation, this process intensifies, and in December the 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, which are cooled to a lesser extent in autumn and winter, convection mainly extends to horizons of 200 m. as a result of which density mixing penetrates to horizons of 300-400 m. Below, mixing is limited by the density structure of waters, and ventilation of the bottom layers occurs due to turbulence, vertical movements and other dynamic processes.

On the roads of Tokyo port

The nature of the circulation of the waters of the sea is determined not only by the influence of the winds acting directly over 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 inflow of Pacific waters depends on it. In the summer, the southeast monsoon increases the circulation of water due to the influx of large amounts of water. In winter, the persistent northwest monsoon prevents water from entering the sea through the Korea Strait, causing a weakening of water circulation.

The waters of the western branch of the Kuroshio, which passed through the Yellow Sea, enter the Sea of ​​Japan through the Korea Strait and spread to the northeast along the Japanese Islands in a wide stream. This stream 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 zone of divergence, which is especially pronounced in summer. Deep water rises in this zone. Having rounded the hill, both branches are connected in the area located to the north-west 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, into the region of the Korea Strait, and passes into a countercurrent along the coasts of the Korean Peninsula. The bulk of the Pacific waters are carried out of the Sea of ​​Japan through the Sangarsky and La Perouse straits, while part of the waters, having reached the Tatar Strait, give rise to the cold Primorsky current, moving south. South of the Peter the Great Bay, the Primorskoye Current turns east and merges with the northern branch of the Tsushima Current. An insignificant part of the waters continues to move south to the Korean Bay, where it flows into the countercurrent formed by the waters of the Tsushima Current.

Thus, moving along the Japan 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 circulation centered in the northwestern part of the sea. In the center of the cycle, the rise of waters is also possible.

Two frontal zones are distinguished in the Sea of ​​Japan - the main polar front formed by the warm and saline 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 have a higher temperature and lower salinity in summer. than the waters of the Primorsky Current. IN winter time the polar front runs somewhat south of the 40 ° north latitude, and near the Japanese islands it runs approximately parallel to them almost to the northern tip of about. Hokkaido. In summer, the location of the front is approximately the same, it only slightly shifts to the south, and off the coast of Japan - to the west. The secondary front passes near the coast of 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 Sangara Straits.

Semidiurnal, diurnal and mixed tides are observed in the sea. In the Korean Strait and in the north of the Tatar Strait - semi-diurnal tides, on the eastern coast of Korea, on the coast of Primorye, near the islands of Honshu and Hokkaido - diurnal, in the Peter the Great and Korean bays - mixed.

Tidal currents correspond to the nature of the tide. 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. So, in the Sangar Strait, tidal currents 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 does not exceed 1.5 m.

In the middle part of the sea, the tides are small. Along the eastern shores of the Korean Peninsula and Soviet 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. In the northern part of the Tatar Strait, the heights of the tides increase, which is due to its funnel-shaped shape.

In addition to tidal fluctuations in the Sea of ​​Japan, seasonal level fluctuations are well expressed. In summer (August - September) there is a maximum rise in the level on all seashores, in winter and early spring (January - April) there is a minimum level position.

In the Sea of ​​Japan, surge fluctuations in the level are observed. During the winter monsoon, the level can rise by 20-25 cm off the western coast of Japan, and decrease by the same amount near the mainland coast. In summer, on the contrary, off the coast of North Korea and Primorye, the level rises by 20-25 cm, and off the coast of Japan 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 prevail in autumn and winter, and eastern waves prevail in spring and summer. Most often, there is a wave with a force of 1-3 points, the frequency of which varies from 60 to 80% per year. In winter, strong excitement prevails - 6 points or more, the frequency of which is about 10%.

In the southeastern part of the sea, due to the stable northwestern monsoon, waves develop from the northwest and north in winter. In summer, weak, most often southwestern, 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 noted in the Sea of ​​Japan.

The northern and northwestern parts of the sea, adjacent to the mainland coast, are annually covered with ice for 4-5 months, the area of ​​\u200b\u200bwhich occupies about 1/4 of the space of the entire sea.

ice coverage

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 is formed in closed bays and gulfs of the continental coast, for example, in Sovetskaya Gavan Bay, De-Kastri and Olga bays. In October - November, the ice cover mainly develops within the bays and gulfs, and from the end of November - the beginning of December, ice begins to form in the open sea.

At the end of December, ice formation in the coastal and open areas of the sea extends to Peter the Great Bay.

Fast ice in the Sea of ​​Japan is not widespread. First of all, it forms 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.

Only the northern bays of the mainland coast freeze completely every year. To the 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 immobile 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 propagating from the mainland. In the east of the sea, the influence of these masses significantly weakens, and at the same time, the role of warm and humid marine air masses increases. The ice cover reaches its maximum development around mid-February. From February to May, conditions are created throughout the sea that favor the melting of ice (on the spot). In the eastern part of the sea, the melting of ice "begins earlier and is more intense than at the same latitudes in the west.

The ice cover of the Sea of ​​Japan varies considerably from year to year. There are cases when the ice cover of one winter is 2 times or more higher than the ice cover of another.

Economic importance

Inhabitants of the Sea of ​​Japan

The fish population of the Sea of ​​Japan includes 615 species. The main commercial species of the southern part of the sea are sardine, anchovy, mackerel, horse mackerel. In the northern regions, mainly mussels, flounder, herring, greenlings and salmon are mined. In summer, tuna, hammerhead fish, and saury penetrate the northern part of the sea. The leading place in the species composition of fish catches is occupied by pollock, sardine and anchovy.

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 by the 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. more development the shelf reaches in the Peter the Great Bay, in the northern part of the Tatar Strait, 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 the 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 the northern regions of the sea, winds of eastern and northeastern directions prevail, and in the southern regions - southerly 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 climatic 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. The west coast is colder throughout the year than the east coast, 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°. The number of cold days (with an 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 the coastal regions of the sea.

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 seawater temperature and salinity, water masses, currents, tides and ice conditions in the Sea of ​​Japan, based on published works and analysis. graphic material Atlas. 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 near the southern coast of Primorye is intensively developed in late October - early November, however, individual cases of its rapid 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 surface water parameters, as well as to intra-annual variability of the intensity and spatial position of the Tsushima Current water branch. 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 Primorye, in the summer, the lower boundary of the UML is at a depth of 5–10 m, and in the southern regions of 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 Pacific waters, saline at this time, from the East China Sea intensifies. 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. The maximum depth of penetration of seasonal salinity fluctuations (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. General idea of vertical structure salinity fields give spatial sections of the distribution of this characteristic and 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.”

Characteristics of water structures and water masses in the northwestern part
Sea of ​​Japan (numerator - February, denominator - August)
The structure of the waters	water masses	Depths, m	Temperature, °С	Salinity, ‰
subtropical		0-200	> 8	33,9-34,0
		0-20	> 21	33,6-33,8
		missing	missing	missing
		30-200	10-15	34,1-34,5
	Deep	>200	0-2	33,9-34,1
		>200		34,0-34,1
Polar zones		0-50	3 - 6	33,9-34,0
		0-30	18-20	33,5-33,9
		missing	missing	missing
		30-200		33,8-34,1
	Deep	>50	0-2	33,9-34,1
		>200		33,9-34,1
Subarctic		0-bottom	0-3	33,6-34,1
		0-20	16-18	33,1-33,7
	Deep	0-bottom	0-3	33,6-34,1
				33,9-34,1
coastal		missing	missing	missing
		0-20	16-19	>32,9
		0-bottom	-2 - -1	>34,0
			missing	missing
		missing	missing	missing
			1 - 5	33,2-33,7
	convection zones	0-bottom	-1 - 1	33,7-34,0
	offshore
Shelf		missing	missing	missing
		0-20		33,0-33,5
		missing	missing	missing
				33,4-33,8

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 the islands lying to the southwest of the latter. 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 best time years - 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 level (during the day) in the bay is 40-50 cm. The most well-developed tidal level fluctuations are developed in the Amur Bay, in its northwestern region, where the maximum level slightly exceeds 50 cm, and least of all - in the Ussuri 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 ​​were noted in the southern and southeastern parts of the sea, while the minimum values ​​were recorded in the northern and northwestern parts. 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.

And the Japanese islands are the frontiers delimiting the waters of the Sea of ​​Japan from the Pacific basin. The Sea of ​​Japan mainly has natural boundaries, only some areas are separated by imaginary lines. The Sea of ​​Japan, although it is the smallest of the Far Eastern seas, belongs to the largest. The area of ​​the water surface is 1062 thousand km2, while the volume of water is about 1630 thousand km3. The depth of the Sea of ​​Japan is on average 1535 m, the maximum depth is 3699 m. This sea belongs to the marginal oceanic seas.

A small number of rivers carry their waters to the Sea of ​​Japan. The largest rivers are: Rudnaya, Samarga, Partizanskaya and Tumnin. Mostly all of this. During the year it is about 210 km 3. Throughout the year fresh water evenly flows into the sea. In July, the full flow of the rivers reaches its maximum. Between the Pacific Ocean and the water exchange is carried out only in the upper layers.

Refers to the Pacific Ocean, or rather, to its western part. Located near Sakhalin Island, between Asia and Japan. Washes the 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 (the contribution is small: 1%).

It is connected with other water bodies 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 its northern part is covered with ice in winter.

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

The problems of the Sea of ​​Japan are directly related to the environment. 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 of people also varies. Among the main problems are the following:

• industrial production;
• release of radioactive substances and oil products;
• oil slicks.

Climatic conditions

The Sea of ​​Japan is divided into three parts by glaciation:

• Tatar vs.;
• Gulf of Peter the Great;
• area from Cape Povorotny to Belkin.

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

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

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

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

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

Thaw often begins in March. The depth of the Sea of ​​Japan contributes to the rapid process of getting rid of ice. It may start at the end of April. If the temperature is kept low, then thawing begins in early June. First, parts of the Gulf of Peter the Great are "opened", in particular, its open water areas, and the coast of the Golden Cape. While the ice begins to recede in the Tatar Strait, it thaws in its eastern part.

Resources of the Sea of ​​Japan

Biological resources are used by man to the maximum extent. Fishing is developed near the shelf. Valuable fish species are herring, tuna and sardines. In the central regions, squids are caught, in the north and southwest - salmon. The algae of 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 characteristics. Due to the climatic conditions in the north and northwest, nature has moderate characteristics, in the south the faunistic complex prevails. Near the Far East there are plants and animals that are characteristic of a warm-water and temperate climate. Here you can see squids and octopuses. In addition to them, there are brown algae, sea urchins, stars, shrimps and crabs. Yet the resources of the Sea of ​​Japan squeak with diversity. There are few places where you can find red ascidians. Scallops, ruffs and dogs are common.

Sea problems

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

In addition, careless fishing can lead to death. Due to fuel and lubricant waste, Wastewater and oil products, fish die, mutate or become contaminated, which great danger for consumers.

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

Ports of companies, enterprises and settlements are the main source of water pollution with 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 contamination with hydrogen sulfide.

tides

Complex tides are characteristic of the Sea of ​​Japan. Their cyclicity in different areas is significantly different. Semi-diurnal is found near the Korean Strait and near the Tatar Strait. Daily tides are inherent in areas adjacent to the coast Russian Federation, Republic of Korea and North Korea, as well as near Hokkaido and Honshu (Japan). Near Peter the Great Bay, the tides are mixed.

The tide level is low: from 1 to 3 meters. In some areas, the amplitude varies from 2.2 to 2.7 m.

Seasonal fluctuations are also not uncommon. They are observed most often in summer; there are fewer in winter. The nature of the wind, its strength also affects the water level. Why are the resources of the Sea of ​​Japan highly dependent.

Transparency

Throughout the sea, the water is of different colors: from blue to blue with a green tint. As a rule, transparency is maintained at a depth of up to 10 m. There is a lot of oxygen in the waters of the Sea of ​​Japan, 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 already by 3 thousand meters it is 70%.