The average water temperature of the Sea of ​​Japan. Sea of ​​Japan (shores in Russia)

The Sea of ​​Japan lies between the mainland Asia, the peninsula of Korea, about. Sakhalin and Japanese islands separating it from the ocean and two neighboring seas. In the north, the border between Japan and Seas 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 deep seas peace. Its area is 1062 km 2, volume - 1631 thousand km 3, average depth- 1536 m, the greatest 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. Korea Strait, divided by the islands of Jeju, Tsushima and Ikizuki to the west (Broughton passage from greatest depth approximately 12.5 m) and eastern (passage of Kruzenshtern 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 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 ° minimum depth above it 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 up to 2300 m high. mountain systems- 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. To the south- east coast the regularity of the monsoon is violated, western and northwestern 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, 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 formed in summer over Eastern Siberia. 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 gale-force winds associated with the passage of cyclones and typhoons, in different areas seas are observed local winds. 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. Average monthly temperature 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. In spring- summer time cloudy weather prevails with frequent fogs.

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.

The geographical position, the outlines of the sea basin, separated from the Pacific Ocean and adjacent seas by high thresholds in the straits, pronounced monsoons, water exchange through the straits only in the upper layers are 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

Essential natural factors- exchange of waters through the straits, the flow of atmospheric 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, the main role in the water balance of the sea is played by 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, northern border Pacific waters is located approximately at 46-47 ° N.L.

Water temperature and salinity

The surface Pacific water is characterized by high temperatures (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, the greatest changes hydrological characteristics take place in surface layer thickness from 10 to 150 m and 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. Changes in the characteristics of the deep water of the Sea of ​​Japan along the vertical are extremely small. 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 sea, and in the south it manifests itself weaker 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 northern and northwestern regions 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 sea ​​temperature decreases quite smoothly with depth and at the 200 m horizon it is approximately 6 °, from here it decreases somewhat faster and at the 250-260 m horizons it is 1.5-2 °, then it decreases very slowly and at the 750-1500 m horizons ( in some areas at 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 northern regions and on the horizons of 500-1500 m in the southern ones. 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 fairly stable state of the waters of the Sea of ​​Japan, although in different areas it is expressed in varying degrees. 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 contributes to increased water circulation due to the influx of a large number 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 of speed 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 eastern shores The Korean Peninsula and the Soviet Primorye before entering the Tatar Strait, they are no more than 0.5 m. 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 near Japanese shores decreases 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 West Side The sea in winter is under the predominant influence of cold and dry air masses spreading from the mainland. In the east of the sea, the influence of these masses 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. Summer in northern part seas penetrate tuna, hammer-fish, saury. Leading place pollock, sardine and anchovy occupy the species composition of fish catches.

And the Japanese islands are the frontiers delimiting the waters of the Sea of ​​Japan from the Pacific basin. The Sea of ​​Japan is predominantly 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. by the most big rivers are: Rudnaya, Samarga, Partizanskaya and Tumnin. Mostly all of this. During the year it is about 210 km 3. During 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.

It is located between the Asian mainland, the Japanese archipelago and Sakhalin Island. Its shores belong to such countries as Japan, South Korea, North Korea and Russia.

The reservoir is significantly isolated from the Pacific waters. Such isolation is reflected both in the fauna and in the salinity of the water. The latter is below the oceanic. The water balance is regulated by inflows and outflows through the straits connecting the sea with neighboring seas and the ocean. Reset fresh water makes an insignificant contribution to water exchange and is no more than 1%.

Geography

The area of ​​the reservoir is 979 thousand square meters. km. The maximum depth is 3742 meters. The average depth corresponds to 1752 meters. The volume of water is 1630 thousand cubic meters. km. The length of the coastline is 7600 km. Of these, 3240 km belong to Russia. From north to south, the length of the sea is 2255 km. Maximum Width corresponds to 1070 km.

Islands

There are no major islands. Most of small islands located off the east coast. The most significant islands are: Moneron (30 sq. km), Okushiri (142 sq. km), Oshima (9.73 sq. km), Sado (855 sq. km), Ulleungdo (73.15 sq. km) , Russian (97.6 sq. km).

gulfs

The coastline is relatively straight. One of the largest is Peter the Great Bay with a total area of ​​about 9 thousand square meters. km. The length from north to south is 80 km, from west to east it is 200 km. The length of the coastline is 1230 km. The cities of Vladivostok and Nakhodka are located in the bay. IN North Korea East Korea Bay is located, and on the island of Hokkaido there is Ishikari Bay. In addition, there are many small bays.

Straits

The Sea of ​​Japan is connected with the East China Sea, the Sea of ​​Okhotsk and the Pacific Ocean by straits. This is the Tatar Strait between Asia and Sakhalin Island with a length of 900 km. La Perouse Strait between Sakhalin Island and Hokkaido Island with a length of 40 km. Sangar Strait between the islands of Honshu and Hokkaido. Its length is 96 km.

The Shimonoseki Strait separates the islands of Honshu and Kyushu. Railway, automobile and pedestrian tunnels are laid under it. The Korea Strait with a length of 324 km connects the reservoir we are considering with East China Sea. It is divided by the Tsushima Islands into 2 parts: the Western Passage and the Eastern Passage (Tsushima Strait). Through this strait, the warm Pacific Kuroshio current enters the reservoir.

Sea of ​​Japan on the map

Climate

The maritime climate is characterized warm water and monsoons. It is colder in the northern and western regions than in the southern and eastern regions. During the winter months, the average air temperature in the north is minus 20 degrees Celsius, and in the south it is plus 5 degrees Celsius. In summer, humid and warm air blows from the northern regions of the Pacific Ocean. August is considered the warmest month. At this time, the average temperature in the north is 15 degrees Celsius, and in the south it is 25 degrees Celsius.

Annual precipitation is minimal in the northwest and maximal in the southeast. Autumn is characterized by typhoons. The height of the waves during this period reaches 8-12 meters. Ice in winter period the Tatar Strait (90% of all ice) and Peter the Great Bay are covered. The ice crust stays on the water for about 4 months.

Ebb and flow

The reservoir is characterized by complex tides. They have a semi-diurnal cycle in the Korea Strait and in the north of the Tatar Strait. On the east coast of Korea, the Far East coast of Russia, on the coast of the Japanese islands of Hokkaido and Honshu, they are diurnal. Mixed tides are typical for Peter the Great Bay.

The amplitude of the tides is relatively low. It varies from 0.5 to 3 meters. In the Tatar Strait, the amplitude ranges from 2.3 to 2.8 meters due to its funnel-shaped shape. The water level also experiences seasonal fluctuations. The highest is observed in summer, and the lowest in winter. The level is also affected by the wind. He is able to change it by 20-25 cm in relation to the Korean coast to the Japanese one.

Water transparency

Sea water has a color from blue to green-blue. Transparency is about 10 meters. The water of the Sea of ​​Japan is rich in dissolved oxygen. This is especially true for the western and northern regions. They are colder and contain more phytoplankton than eastern and southern regions. The oxygen concentration is 95% near the surface and decreases to 70% at a depth of 3,000 meters.

Fishing in the Sea of ​​Japan

Fishing

The main economic activity is fishing. It is carried out near the continental shelf, and priority is given to such fish as herring, tuna, sardines. Squid are caught mainly in the central sea areas, and salmon off the southwestern and northern shores. Along with fishing, the production of algae is well developed. The Russian whaling fleet is based in Vladivostok, although it fishes in the northern seas.

In size, it is inferior to the sea and, its area is up to 1,062 tons km2, and the most deep depression reaches up to 3745 m. It is generally accepted that the average depth is 1535 m. geographic location indicate that the sea belongs to the marginal oceanic seas.

There are medium and small islands in the sea. The most significant of them are Rishiri, Oshima, Sado, Momeron, Russian. Almost all islands are located along the mainland in the eastern part.

The coastline is slightly indented, the outlines of Sakhalin Island are especially simple. with the Japanese islands has a more indented coastline. Main major ports the seas are Eastern port, Wonsan, Kholmsk, Vladivostok, Tsuruga, Chongjin.

Currents of the Sea of ​​Japan

Tides in the Sea of ​​Japan

In different areas of the sea, the tides are expressed differently, they are especially distinct in the summer and reach up to three meters in the Korea Strait. To the north, the tides decrease and do not exceed 1.5 m. This is due to the fact that the bottom has a funnel shape. The greatest fluctuation is observed in the northern and southern extreme areas of the sea in summer.

I offer you interesting video"Parallel world - the Sea of ​​Japan" from the series "Russian underwater expeditions".

—