Sea of Japan (shores in Russia).
The Sea of Japan belongs to the Pacific Ocean basin and is a marginal sea, which is separated from the Pacific Ocean by the Japanese Islands and Sakhalin Island. The Sea of Japan washes the shores of Russia and Japan.
Characteristics of the sea
The area of the Sea of Japan is 1062 sq. Km. The volume of water is 1630 thousand cubic km. The depth of the sea ranges from 1753 to 3742 meters.The northern waters of the Sea of Japan are covered with ice in winter.
Major port cities by the sea: Vladivostok, Nakhodka, Vanino and Sovetskaya Gavan.
The coastline of the sea is weakly indented, but it has several bays, the largest of which are bays: Olga, Peter the Great, Ishikari and the East Korean Gulf.
More than 600 species of fish live in the waters of the Sea of Japan.
Commercial use of the sea
For economic purposes, the waters of the Sea of Japan are used in two directions - industrial fishing and transport shipping.Along with the industrial fishing, there is the extraction of mussels, scallops, squid and seaweed (kelp and seaweed).
Vladivostok is the end point of the Trans-Siberian railway, where there is a transshipment base where cargo is reloaded from railway wagons to sea cargo ships.
Ecology of the Sea of Japan
Due to the large number of sea transport vessels and oil tankers in the waters of port cities, there are frequent cases of oil pollution of sea waters. Waste products of people and port industrial enterprises also contribute to the pollution.Archaeological research in the Sea of Japan.
In ancient times, tribes of the Mongol race lived on the western shores of the Sea of Japan. At the same time, the Japanese islands were settled by the ancestors of the Japanese - the Malay and Polynesian Yamato tribes.
In Russia, for the first time, information about the Sea of Japan appeared in the 17th century, after the famous Russian traveler Vasily Poluyarkov in 1644-1645 carried out a rafting down the Amur to its mouth.
Archaeological research for the first time on Sakhalin Island was carried out in 1867, then during archaeological excavations at the southern end of Lake Lebyazhye, the first artifacts were found confirming the presence of ancient settlements on Sakhalin Island.
It is separated from it by the Japanese Islands and Sakhalin Island. Washes the shores of Russia, Korea and Japan, the DPRK. In the south, a branch of the warm Kuroshio current enters.
Area - 1.062 million sq. Km.
The greatest depth is 3742 m.
The northern part of the sea freezes in winter.
Fishing; catch of crabs, trepangs, algae.
japan sea map
japan sea map
The main ports are Vladivostok, Nakhodka, Vostochny, Sovetskaya Gavan, Vanino, Aleksandrovsk-Sakhalinsky, Kholmsk, Niigata, Tsuruga, Maizuru, Wonsan, Hinnam, Chongjin, Busan.
Climate of the Sea of Japan
moderate, monsoon. The northern and western parts of the sea are much colder than the southern and eastern ones. In the coldest months (January-February), the average air temperature in the northern part of the sea is about −20 ° С, and in the south it is about + 5 ° С. The summer monsoon brings with it a warm and wet air.
The average air temperature of the warmest month (August) in the northern part is about + 15 ° С, in the southern regions it is about + 25 ° С. In autumn, the number of typhoons caused by hurricane winds increases. The largest waves have a height of 8-10 m, and during typhoons, the maximum waves reach a height of 12 m.
In summer, the surface water temperature rises from 18-20 ° C in the north to 25-27 ° C in the south of the sea.
Salinity of water Sea of Japan 33.7-34.3%, which is slightly lower than the salinity of the waters of the World Ocean.
Tides in Sea of Japan expressed clearly, to a greater or lesser extent in different areas. The greatest level fluctuations are observed in the extreme northern and extreme southern regions. Seasonal sea level fluctuations occur simultaneously over the entire sea surface, the maximum level rise is observed in summer.
Flora and fauna
The underwater world of the northern and southern regions Sea of Japan is very different. In the cold northern and northwestern regions, the flora and fauna of temperate latitudes has formed, and in the southern part of the sea, south of Vladivostok, a warm-water faunistic complex prevails. Warm-water and temperate fauna mixes off the shores of the Far East. Here you can find octopuses and squids - typical representatives of warm seas. At the same time, vertical walls, overgrown with anemones, gardens of brown algae - kelp - all this resembles the landscapes of the White and Barents Seas.
V Sea of Japan a huge abundance of starfish and sea urchins, of various colors and different sizes, there are ophiuras, shrimps, small crabs (Kamchatka crabs are found here only in May, and then they go further into the sea). On the rocks and stones live bright red ascidians. The most common shellfish are scallops. Of the fish, blend dogs and sea ruffs are often found.
In the Sea of Japan, the ice cover reaches its maximum development in mid-February. On average, ice covers 52% of the Tatar Strait and 56% of the Peter the Great Gulf.
Ice melting begins in the first half of March. In mid-March, the open waters of the Peter the Great Gulf and the entire coastal area up to Cape Zolotoi are cleared of ice. The boundary of the ice cover in the Tatar Strait is retreating to the northwest, and ice is cleared in the eastern part of the strait at this time. The early clearing of ice from the sea begins in the second decade of April, later - at the end of May - beginning of June.
The nature of our planet is beautiful and amazing. You can admire its beauty indefinitely.
One of the most attractive, unexplored, unpredictable elements for a person at all times was water. Among the diversity of rivers, seas and oceans, an interesting object for study is the Sea of Japan, the resources of which belong to several countries and play an important role in their development.
Description
This sea belongs to the Pacific Ocean basin. Along with the Bering and Okhotsk, it is listed as one of the largest and deepest seas in Russia. It is of great importance in the implementation of transport and cargo transportation, it is a source of mineral resources. The Sea of Japan is also distinguished by a high level of production of commercial fish species.
Its area stretches over an area of approximately 1,100 square kilometers, with a volume of 1,700 cubic kilometers. The average depth of the Sea of Japan is 1550 meters, the greatest is more than 3500 meters.
The sea is connected with other seas and the ocean by straits. Nevelsky connects it with the Sea of Okhotsk, the Korean one with the East China. Shimonoseki separates the Sea of Japan and the Inland Sea of Japan, and is also connected with the Pacific Ocean through the Sangar Strait.
Location
The Sea of Japan lies between the Asian mainland and the Korean Peninsula. Washes the land of several countries: Russia, Japan, DPRK, Republic of Korea.
A characteristic of the Sea of Japan is also the presence of small islands such as Popov, Okushiri, Russian, Oshima, Putyatin, Sado and others. Basically, the cluster of islands is concentrated in the eastern part.
Waters form bays, for example, Sovetskaya Gavan, Isikari, Peter the Great. And also capes, the most famous of them are Cape Lazarev, Korsakov, Soya.
The Sea of Japan has many shipping ports. Some of the most significant are Vladivostok, Nakhodka, Aleksandrovsk-Sakhalinsky, Tsuruga, Chkhondzhin and others. They organize the transportation of goods not only across the Sea of Japan, but also beyond its borders.
Climate
The weather characteristics of the Sea of Japan are temperate and subtropical climate, stable winds.
Its geographical position and great length have divided it into two climatic parts: the northwestern and southeastern zones.
Water temperature in different parts depends on the circulation of streams, heat exchange with the atmosphere, the time of the year, as well as the depth of the Sea of Japan. In the northern and western parts, the water and air temperature is much lower due to the influence of the cold Sea of Okhotsk. Water and air masses coming from the Pacific Ocean play an important role in the eastern and southern zones, so the temperatures are much higher.
In winter, the sea is prone to hurricanes, storms, the duration of which can be several days. Autumn period characterized by strong winds that form high, powerful waves. In summer, stable warm weather prevails in both climatic zones.
Water characteristics
In the winter season, the water temperature in different regions is very different. The northern part is characterized by ice coverage of the surface, while in the southern part the approximate temperature is 15 degrees.
In summer, the northern waters of the Sea of Japan warm up to 20 degrees, the southern - up to 27.
The water balance consists of two important components: the amount of precipitation, the evaporation of water from the surface, and the exchange of water, which is carried out with the help of straits.
Salinity consists of the resources of the Sea of Japan, water exchange with other seas, the Pacific Ocean, the amount of precipitation, ice melting, the season, and some other factors. The average salinity is about 35 ppm.
The clarity of the water depends on its temperature. In winter, it is higher than in the warm season, therefore, in the northern part, the density always has higher rates than in the southern part. According to this principle, the oxygen saturation of the water is distributed.
Development of transport routes
The role of the Sea of Japan in organizing cargo transportation is very great both for Russia and for other countries.
Sea transport and cargo transportation is highly developed, which is of great importance for Russia. The Trans-Siberian railway ends in the city of Vladivostok. Here, unloading of railroad and loading of sea transport is carried out. In the future, along the sea routes, passengers and cargo are sent to other ports of different countries.
Fishing
The fish resources of the Sea of Japan are distinguished by high productivity, diversity, including a large number of fish species. Its waters can accommodate over 3000 inhabitants. Their population depends on the climate conditions in different regions.
In the warm southeastern part, the catch of mackerel, saury, sardine, horse mackerel, anchovies, flounder, and some other species of fish is widespread. A large number of octopuses can also be found here. The central regions are inhabited by squid and crabs. In the northwest, salmon, pollock, cod and herring are caught. The sea is also teeming with trepangs, mussels, oysters.
Recently, production facilities have been actively developing, where crayfish, sea urchins are cultivated, as well as algae, seaweed, kelp, molluscs, scallops are grown. These aquacultures are also resources in the Sea of Japan.
In addition to commercial species, the Sea of Japan is rich in other inhabitants. Here you can find seahorses, dolphins, whales, seals, sperm whales, beluga whales, small shark species and other types of marine inhabitants.
Ecology
Like the resources of the Sea of Japan, ecological problems need separate study. The impact of the life of the population on the environment is different in different regions.
The main source of pollution is the discharge of industrial and domestic wastewater. The greatest negative impact is exerted by the release of radioactive substances, petroleum products, chemical and coal industries, and metalworking. Waste of various production flows into the waters of the Sea of Japan.
Extraction and transportation of oil is associated with great risks for the environment. In the event of a leak, the oil stain is difficult to remove. It causes enormous damage to the ecology of the sea and its inhabitants.
Transport waste from numerous ports, sewerage cities that fall into the sea also cause considerable harm.
Studies of the water of the Sea of Japan show a fairly high level of pollution. The composition contains many chemical elements discharged by industries, as well as heavy metals, phenol, zinc, copper, lead, mercury, ammonium nitrogen compounds and other substances. All this contributes to the enormous pollution of the environment.
The leaders of the countries with which the sea borders, carry out targeted operational and preventive actions in order to preserve the unique nature, purity and its inhabitants. It is necessary to control, suppress, and severely punish the cases of chemical and oil waste emissions into the waters. Enterprises and sewage drains must be equipped with cleaning filters.
These control measures will be able to prevent environmental pollution, protect numerous inhabitants from death, and also preserve human health.
The Sea of Japan is one of the most valuable resources that must not only be actively used, but also protected from the negative consequences of human life.
The information provided will help assess the resources of the Sea of Japan, study its characteristics, get to know the inhabitants, and find out the ecological aspects.
The study of this sea has been going on for a long time. Nevertheless, there are many questions and problems that require research and targeted action.
The Sea of Japan is a sea within the Pacific Ocean, separated from it by the Japanese Islands and Sakhalin Island. It is connected with other seas and the Pacific Ocean through 4 straits: Korean (Tsushima), Sangar (Tsugaru), La Perouse (Soya), Nevelskoy (Mamiya). Washes the shores of Russia, Korea, Japan and North Korea. In the south, a branch of the warm Kuroshio current enters.
Physical and geographical characteristics and hydrometeorological conditions
The Sea of Japan is located in the northwestern part of the Pacific Ocean between the Asian mainland, the Japanese Islands and Sakhalin Island in geographic coordinates 34 ° 26 "-51 ° 41" N, 127 ° 20 "-142 ° 15" E In terms of 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 joins the Sea of Okhotsk straits Nevelskoy and La Perouse (Soy), in the east - with the Pacific Ocean of the Sangar (Tsugaru) Strait, in the south - with the East China Sea and the Korea (Tsushima) Strait. The shallowest of them, the Nevelskoy Strait, has a maximum depth of 10 m, and the deepest Sangarsky Strait is about 200 m. Subtropical waters flowing 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 maximum depth of the rapids is 135 m. The second largest water exchange is the Sangar Strait, which is 19 km wide. The La Perouse Strait, the third largest water exchange, has a width of 44 km and a depth of up to 50 m. The area of the sea surface is 1062 thousand km 2, and the total volume of sea waters is 1631 thousand km 3.
The nature bottom relief The Sea of Japan is subdivided into three parts: northern - north of 44 ° N, central - between 40 ° and 44 ° N. and south - south of 40 ° N. 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 Tatar Strait shallow. from west to east, northeast. From the south, its border is defined by the Yamato Rise. The most complex bottom relief is the southern part of the sea. Between the Yamato Upland and the slope of Honshu Island, the Honshu Basin stretches with a depth of about 3000 m. depths of 120-140 m.
A feature of the morphology of the Sea of Japan bottom 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, 15 to 25 km wide, is noted along the southern coast of Primorye. The shelf reaches greater development in the Peter the Great Gulf, in the northern part of the Tatar Strait, the East Korea Gulf and in the Korea Strait region.
total length the coastline of the sea is 7531 km. It is weakly indented (with the exception of the Peter the Great Gulf), sometimes almost straight. The few islands lie mainly near the Japanese Islands and in the Peter the Great Gulf.
The Sea of Japan is located in two climatic zones: subtropical and temperate. Within these zones, two sectors are distinguished with different climatic and hydrological conditions: the harsh cold northern one (partially covered with ice in winter) and the soft, warm one adjacent to Japan and the coast of Korea. The main factor shaping the sea climate is the monsoon circulation of the atmosphere.
The main baric formations that determine the atmospheric circulation over the Sea of Japan are the Aleutian depression, the Pacific subtropical maximum, and the Asian center of atmospheric action located above the mainland. Changes in their position during the year determine the monsoon 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 values of winter pressure over summer in the direction from north-east to south-west, as well as a pronounced seasonal variability. In the annual course of pressure, most of the sea is characterized by the existence of a pressure maximum in winter and a minimum in summer. In the northeastern part of the sea - at the northern half of the island. Honshu, about. Hokkaido and off the southern coast of Sakhalin have two pressure peaks: 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 features of the distribution of atmospheric pressure considered above determine General characteristics wind regime over the waters of the Sea of Japan. Off the mainland coast during the cold season, strong northwestern winds prevail at speeds of 12-15 m / s. The frequency of occurrence 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 eastern coast, the winds of the cold season are not as pronounced in direction as they are off the mainland coast. Wind speeds are lower here, but also decrease on average from north to south. Every year in late summer and early autumn, tropical cyclones (typhoons) emerge on the Sea of Japan, accompanied by hurricane winds. During the cold season, the frequency of storm winds caused by deep cyclones increases sharply. In the warm period of the year, southerly and southeasterly winds prevail over the sea. Their frequency is 40 - 60%, and their speeds, as in winter, decrease on average from north to south. In general, the wind speed in the warm season is much lower than in winter. During the transitional seasons (spring and autumn), the direction and speed of the wind undergo significant changes.
For the open areas of the northwestern regions of the sea in winter, the prevailing winds are northwestern and northern directions. In the southwest direction, the winds turn from northwest to west, and in areas adjacent to southern Sakhalin and Hokkaido, from northwest to north and even to northeast. V warm season such a natural picture general structure wind fields cannot be established for the entire sea. However, it is found that in the northern regions of the sea, winds from the east and north-east prevail, and in the south - from the south.
In the sea of Japan air temperature changes naturally both from north to south and from west not east. In the northern, more severe climatic zone, moderate annual temperature is 2 °, and in the south, in the subtropics - + 15 °. In the seasonal course of air temperature, the minimum occurs in the winter months (January - February), and the maximum in August. In the north, the average monthly January temperature 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 than the east coast throughout the year, with temperature differences increasing from south to north. In winter they are higher 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 radiation balance of heat on the surface, which is compensated by a constant inflow of heat with waters coming through the Korea Strait. The water balance of the sea is mainly determined by its water exchange with adjacent basins through three straits: Korean (tributary), Sangar and La Perouse (runoff). Compared to the amount of water exchange through the straits, the contribution to the water balance of precipitation, evaporation and continental runoff is negligible. Due to its insignificance, the continental runoff exerts its influence only in the coastal areas of the sea.
The main factors determining hydrological regime The Sea of Japan is characterized by the interaction of its surface waters with the atmosphere against the background of changing climatic conditions and water exchange through straits with adjacent water basins. The first of these factors is decisive for the northern and northwestern part of the sea. Here, under the influence of northwestern monsoon winds that bring cold air masses from the mainland in the winter season, surface waters are significantly cooled 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, the 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 (up 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 waters. 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 branch 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 one.
This section summarizes the basic information about the spatial distribution and variability of temperature and salinity. sea water, water masses, currents, tides and ice conditions of the Sea of Japan, based on published works and analysis of the Atlas graphic material. All values of air and water temperature are given in degrees Celsius (o С), and salinity - in ppm (1 g / kg = 1 ‰).
On the 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, the position of which during all seasons of the year remains approximately constant. This front separates the warm and salty waters of the southern sector of the sea from the colder and freshened waters of the northern part of the sea. The horizontal temperature gradient on the surface across the front varies throughout the year from the maximum values of 16 ° / 100 km in February, to the minimum - 8 ° / 100 km in August. In November-December, a secondary front with a gradient of 4 ° / 100 km forms to the north of the main front, parallel to the Russian coast. The temperature drop within the entire water area of the sea 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 the temperature in the Korea Strait drops to 12-14 °. The magnitudes of seasonal changes in water temperature on the surface generally increase from the southeast to the northwest from the minimum values (12-14 0) near the Korea Strait - to the maximum (18-21 0) in the central part of the sea and near the bay. Peter the Great. Relative to the average annual values, below zero air temperature anomalies occur in the period from December to May (during the winter monsoon), and positive temperature anomalies occur from June to November (summer monsoon). The strongest cooling (negative anomalies up to -9 °) occurs in February in the region of 40-42 ° N, 135-137 ° E, and the greatest heating (positive anomalies over 11 °) is observed in August near the Petra Bay Great.
With increasing depth, the range of spatial changes in temperature and its seasonal fluctuations at different horizons significantly narrows. Already at the 50 m horizon, seasonal temperature fluctuations do not exceed 4-10 0. The maximum amplitudes of temperature fluctuations at this depth are noted in the southwestern part of the sea. On the 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, but its meandering is manifested in the section between 131 ° and 138 ° E. In the central part of the basin to the north of the main front, the temperature on this horizon is 1–2 0, and to the south it increases abruptly to 4–5 °. At a depth of 500 m, the temperature throughout the sea changes insignificantly. It is 0.3-0.9 ° and practically does not experience seasonal variations. The frontal division zone does not appear at this depth, although in the area adjacent to the coast of Japan and Korea, a slight increase in temperature is noted, due to the transfer of heat into the deep layers by vortex formations actively forming in this area of the sea.
Among the regional features of the horizontal temperature distribution, upwelling zones, eddy formations, and coastal fronts should be noted.
Upwelling near the southern shores of Primorye is intensively developed in late October - early November, but individual cases of its fleeting manifestation can be identified in September - early October. The diameter of a cold water spot in the upwelling zone is 300 km, and the temperature difference between its center and the surrounding waters can reach 9 0. The emergence of upwelling is caused not only by the intensification of deep-water circulation, but also, mainly, by the monsoon change of winds, which is confined to this particular period of time. Strong northwest winds blowing from the mainland create favorable conditions for the development of upwelling in the 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 area of the Primorsky Current), the frontal section is formed in early 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 bounded 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 regions. These waters, after the final destruction of the thermocline, spread towards the open 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 in the field of the horizontal temperature distribution.
The lack 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 separation of the water column into two layers: active layer characterized by seasonal variability, and deep, where both seasonal and spatial variability are almost not traced. 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 associated with the downward movement of waters observed here in the center of the vast anticyclonic meander of the East Korean Current, as well as with variations in the position of the frontal zone at its northern and eastern borders. Seasonal temperature fluctuations are traced up to the horizon of 400 m off the coast of Japan, which is a consequence of the sinking of water in anticyclonic gyres formed during the interaction of the Tsushima Current with the continental slope. High values of the penetration depth of seasonal temperature fluctuations (up to 400-500 m) are found in the Tatar Strait. This is mainly associated with convective processes and significant seasonal variability of surface water parameters, as well as with intra-annual variability of the intensity and spatial position of the water branch of the Tsushima Current. Off the coast of southern Primorye, seasonal variations in water temperature are manifested only in the upper three hundred meter layer. Below this border, seasonal temperature fluctuations are almost not traced. As can be seen in 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 sea volume, 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): upper quasi-uniform layer(Videoconferencing), seasonal jump layer temperature and main thermocline... The characteristics of these layers in different seasons in the sea area have regional differences. Near the coast of Primorye in the summer season, 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 is intensified 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, 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 even absent. The seasonal thermocline here begins to form with the onset of the spring warming of 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 the distribution of salinity 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 waters exceeds 34 ‰, which is mainly due to the influx of highly saline waters (34.6 ‰) from the East China Sea. Less saline waters are concentrated in the coastal regions of the Asian mainland and islands, where their salinity decreases to 33.5 ‰ -33.8 ‰. In the coastal regions of the southern half of the sea, the minimum salinity 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 waters brought in from the East Kamchatka Sea. In the northern part of the sea, in addition to the summer-autumn decrease, a second minimum of salinity is formed in spring during the melting ice of the Tatar Strait and Peter the Great Bay. The highest salinity values in the southern half of the sea occur in the spring-summer season, when the inflow of salty Pacific waters from the East China Sea increases. A gradual retardation of the salinity maxima from south to north is typical. If in the Korea Strait the maximum occurs in March-April, then near 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 saltiest waters are located near the Korea Strait. In spring, these features are generally preserved, but the area of low salinity values in coastal areas due to ice melting and an increase in continental runoff, as well as the amount of precipitation, increases. Further, by summer, following the influx of surface waters of the East China Sea, freshened due to the abundance of precipitation, into the sea through the Korea Strait, the general background of salinity in the sea 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, when the northern winds intensify, the waters of the upper layer are driven off and mixed, and a slight increase in salinity is observed. The minimum seasonal changes in salinity on the surface (0.5-1.0 ‰) are noted in the central part of the sea, and the maximum (2-15 ‰) - in the coastal areas of the northern, northwestern part and in the Korea Strait. At great 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, even 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 a horizon of 100 m, horizontal salinity changes fall within the range of 0.5 ‰, and at a horizon of 200 m (Fig. 3.10), in all seasons of the year, they do not exceed 0.1 ‰, i.e. value typical for deep waters... Somewhat higher values are observed only in the southwestern part of the sea. It should be noted that the horizontal distributions of salinity at depths greater than 150-250 m are very similar: the minimum salinity is confined to the northern and northwestern parts of the sea, and the maximum - to the southern and southeastern parts. At the same time, the halin front, 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 monotonic increase in salinity with depth is observed in all seasons of the year, except for the winter, when it is practically constant throughout the entire water column. In the southern and southeastern parts of the sea, in the warm season, below the freshened surface waters, an intermediate layer of increased salinity is clearly distinguished, formed by highly saline waters (34.3-34.5 ‰) flowing 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, salinity in the core of this layer decreases and reaches 34.1 ‰ at the periphery. In the winter season, this layer is not pronounced. At this time of the year, vertical salinity changes 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 forms in the winter season due to the immersion of surface waters in the frontal division 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 penetration depth of seasonal salinity fluctuations (200-250 m) is observed in the zone of distribution of Tsushima Current waters. 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 south and southwest of the bay. Peter the Great seasonal variations in salinity appear only in the upper 100-150 m layer. Here, the influence of the Tsushima Current waters is weakened, and the 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 water areas of bays and bays. This area with the minimum values of the depth of manifestation of seasonal fluctuations in salinity is interspersed with zones with higher values, the origin of which is associated with the penetration of branches of the highly saline waters of the Tsushima Current to the northwestern shores of the sea. A general idea of the vertical structure of the salinity field is given by the spatial sections of the distribution of this characteristic and table values given in the atlas.
Water masses
In accordance with the considered features of the spatio-temporal 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 limited 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 coastal waters of the Japanese Islands, and in the cold northern one (PSA) - by mixing of coastal waters freshened by the continental runoff with the waters of the 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 ranges from 0 to 120 m.
In the below intermediate In the warm season, a water mass of increased salinity (its varieties: PPST - subtropical, PPSTT - transformed), the core of which is located at depths of 60-100 m, and the lower boundary at a depth of 120-200 meters, is released to the layer of waters in most of the sea during the warm season. Salinity in its core is 34.1-34.8 ‰. In the 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 allocated.
Deep The water mass, usually called the water of the Sea of Japan proper, covers the entire lower layer (deeper than 400 m) and is characterized by uniform values of temperature (0.2-0.7 °) and salinity (34.07-34.10 ‰). The high content of dissolved oxygen in it indicates the active renewal of deep layers by surface waters.
V coastal areas In the northwestern part of the sea, due to significant freshening by continental runoff, exacerbation of tidal phenomena, wind upwellings and winter convection, a specific coastal structure of waters is formed, represented by a vertical combination of surface waters (SP), which are less saline than the waters of adjacent areas of the open sea, and have more significant fluctuations in temperature, as well as subsurface waters (SPS) of higher salinity and lower temperatures, formed during winter convection. In some areas (Tatar Strait, Peter the Great Bay), in the course of intensive ice formation in winter, a highly saline (up to 34.7 ‰ and very cold (up to -1.9 0) water mass (LW)) is formed. and drain along the continental slope, participating in the ventilation of the deep layers.
On the part of the shelf, where freshening by continental runoff is small, the weakening or even destruction of water stratification by tidal mixing occurs. As a result, a weakly stratified shelf structure is formed, consisting of a relatively cold freshened surface shelf water mass (PS) and a relatively warm and freshened shelf modification of deep waters (HS). At 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 forming in the zones of tidal mixing are drawn into the circulation existing in the northwestern part of the sea and spread beyond the boundaries of the area of their formation, usually considered as “waters of the Primorsky Current”.
| Characterization of the structures of waters and water masses in the northwestern part |
||||
| Sea of Japan (numerator - February, denominator - August) |
||||
| Water structure |
Water masses |
Depth of occurrence, m |
Temperature, |
Salinity, ‰ |
| Subtropical |
0-200 |
> 8 |
33,9-34,0 |
|
| 0-20 |
> 21 |
33,6-33,8 |
||
| absent |
absent |
absent |
||
| 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 |
||
| absent |
absent |
absent |
||
| 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 |
absent |
absent |
absent |
|
| 0-20 |
16-19 |
>32,9 |
||
| 0-bottom |
-2 - -1 |
>34,0 |
||
| absent |
absent |
|||
| absent |
absent |
absent |
||
| 1 - 5 |
33,2-33,7 |
|||
| Convection zones |
0-bottom |
-1 - 1 |
33,7-34,0 |
|
| on the shelf |
||||
| Shelf |
absent |
absent |
absent |
|
| 0-20 |
33,0-33,5 |
|||
| absent |
absent |
absent |
||
| 33,4-33,8 |
||||
Note: In February, the surface and deep water masses of the subarctic structure do not differ in their thermohaline characteristics.
Circulation of waters and currents
The main elements of the water circulation scheme given in the atlas are warm currents in the southern and eastern sectors and cold currents in 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, which consists of two branches - a calm seaward and more turbulent, moving under the very coast of Honshu Island, and the East Korean Current, spreading as a single stream along the coast of the Korean Peninsula. At a latitude of 38-39 ° N The East Korean Current is divided into two branches, one of which, skirting the Yamato Rise from the north, follows in the direction of the Sangar Strait, the other, deviating to the southeast, partly closes the anticyclonic circulation off the southern coast of Korea, and the other merges with the seaward branch Tsushima current. The unification of all branches of the Tsushima and East Korean currents into a single stream occurs near 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 in the direction of the Tatar Strait. Upon reaching the La Perouse Strait, the bulk of this flow is carried out from the sea, and only a small part of it, spreading within the Tatar Strait, gives rise to a cold current spreading southward along the mainland coast of Primorye. The divergence zone at 45-46 ° N this current is divided into two parts: the northern - the Limanny (Shrenka) current and the southern - the Primorsky current, which divides into two branches to the south of the Peter the Great Gulf, one of which gives rise to the cold North Korean Current, and the other turns to the south and, in contact with north stream of the East Korean Current, forms a large-scale cyclonic gyre centered at 42 ° N, 138 ° E over the Japan Sea 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 division zone. Least expressed element general scheme circulation is the West Sakhalin Current, following in a southern direction from latitude 48 ° N. along the southern coast of about. Sakhalin and the carrying part of the water flow of the Tsushima current separated from it in the water area 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 water inflow, 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 is retained 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 dies down 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). During the transitional seasons (spring, autumn), the characteristics of currents have average values between summer and winter. The velocities of the currents in the 0-25 layer are almost constant, and with a further increase in depth they decrease to half of the surface value at a depth of 100 meters. The atlas shows the schemes of water circulation on the surface of the Sea of Japan in different seasons, obtained by calculation methods.
Tidal phenomena
Tidal movements in the Sea of Japan are mainly formed by the semidiurnal tidal wave M, which is almost purely stagnant, with two amphidromic systems located near the borders of the Korea and Tatar straits. Synchronous fluctuations of the tidal profile of the sea level and tidal currents in the Tatar and Korean 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 interconnection of the sea with adjacent basins through three main straits contributes to the formation of an induced tide in it, the effect of which, based on morphological features (shallowness of the straits compared to the sea depth), affects the straits and areas immediately adjacent to them. Semi-diurnal, 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 already at Busan does not exceed 1.5 m. In the middle part of the sea, the tides are low. Along the eastern shores of Korea and the Russian Primorye, up to the entrance to the Tatar Strait, they are no more than 0.5 m. The same magnitude of tides are 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 shape.
In the open areas of the sea, semi-daily tidal currents with velocities of 10-25 cm / s are mainly manifested. More complex tidal currents in the straits, where they have very significant velocities. So, in the Sangar Strait, the tidal current velocities reach 100-200 cm / s, in the La Perouse Strait - 50-100 cm / s, in the Korean Strait - 40-60 cm / s.
Ice conditions
According to ice conditions, the Sea of Japan can be divided into three regions: the Tatar Strait, the region 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 Gulf; in the rest of the water area, with the exception of closed bays and bays in the northwestern part of the sea, it does not always form. The coldest region is the Tatar Strait, where in the winter season more than 90% of all ice observed in the sea is formed and localized. According to long-term data, the duration of the ice period in the 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 in the tops of bays and bays, closed from wind, waves and having a freshened 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 Strait, 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 the ice cover along the coast of Sakhalin Island occurs faster than near the mainland coast. Accordingly, there is more ice in the eastern part of the Tatar Strait at this time than in the western one. By the end of December, the amount of ice in the eastern and western parts is leveled, 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, ice covers 52% of the Tatar Strait and 56% of the Peter the Great Gulf.
Ice melting begins in the first half of March. In mid-March, the open waters of the Peter the Great Gulf and the entire coastal area up to Cape Zolotoi are cleared of ice. The boundary of the ice cover in the Tatar Strait is retreating to the northwest, while ice is cleared in the eastern part of the strait at this time. The early clearing of ice from the sea occurs in the second decade of April, later - at the end of May - beginning of June.
Hydrological conditions 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 parallels 42 0 17 "and 43 ° 20" N. NS. and meridians 130 ° 41 "and 133 ° 02" E. The waters of the Peter the Great Gulf are bounded from the sea side by a line connecting the mouth of the Tumannaya River (Tyumen-Ula) with the Povorotny Cape. Along this line, the width of the bay reaches almost 200 km.
By the Muravyov-Amursky peninsula and a group of islands located to the south-west of it, the Peter the Great Bay is divided into two large bays: Amursky and Ussuriysky. Amur Bay represents the northwestern part of the 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 islands of Russian, Popov, Reinike, Rikorda. The southern border of the Amur Bay is the line connecting Cape Bruce with the Tsivolko and Zheltukhin Islands. The bay stretches northwestward for about 70 km, and its width, averaging 15 km, ranges from 13 to 18 km. Ussuri Bay occupies the northeastern part of the Peter the Great Bay. From the north-west, it is bounded by the Muravyov-Amursky peninsula, the Russian island and the islands lying to the south-west of the latter. The southern border of the bay is considered to be the line connecting the southern extremities of the Zheltukhin and Askold islands.
The area of the Peter the Great Bay is about 9 thousand km 2, and the total length of the coastline, including the islands, is about 1500 km. The vast waters of the bay have 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 Vostochny Bosphorus strait. This group consists of four large and many small islands. The largest in this group is Russky Island. The southern group - the Rimsky-Korsakov Islands - includes eight islands and many islets and rocks. The most significant in it is the island of Bolshoi Pelis. In the eastern part of the bay there are two more large islands: Putyatin, located among Strelok Bay, and Askold, lying to the south-west of Putyatin Island.
The most significant strait is the Eastern Bosphorus, which separates the Russian island from the Muravyov-Amursky 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 bays. The most significant of them are Posiet, Amursky, Ussuriysky, Strelok, Vostok and Nakhodka (America) bays. Slavyansky Bay, Tabunnaya, Narva and Perevoznaya bays protrude into the western coast of the southern part of the Amur Bay. The coastline of the northeastern part of the Amur Bay and the northwestern part of the Ussuriisk Bay is relatively weakly indented. Sukhodol, Andreeva, Telyakovsky, Vampausu and Podyapolsky bays are distinguished on the eastern coast of the Ussuriysky Bay. Headlands protruding far into the sea form rocky, mostly steep shores, bordered by stones. The largest of peninsulas are: Gamow, Bruce and Muravyov-Amursky.
Bottom relief Peter the Great Bay is characterized by developed shallow waters and a steep continental slope, indented by underwater canyons. The continental slope runs 18 and 26 miles south of the islands of Askold and Rikord, 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 rises smoothly from south to north. In the eastern part of the bay, the depths reach 100 m and more, and in the western part they do not exceed 100 m. Seaward of 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. Secondary bays - Amur, Ussuri, Nakhodka - are shallow. In the Amur Bay, the bottom relief is quite even. From the shores of the summit of the bay, there are extensive shallows. From the north-western coast of Russkiy Island to the opposite coast of the bay stretches an underwater rapids with depths of 13-15 m.At the entrance to the Ussuriisk bay, the depths are 60-70 m, then decrease to 35 m in the middle part of the bay and to 2-10 m at the top ... In 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 less than 10 m.
Meteorological regime Peter the Great Bay, the monsoon circulation of the atmosphere, the geographical position of the region, the impact of the cold Primorsky and warm Tsushima (in the south) currents are determined. cold continental air from the mainland to the sea (winter monsoon). As a result, frosty, slightly cloudy weather with no big amount precipitation and the prevalence of winds from the north and northwest directions. In spring, the wind regime is unstable, the air temperature is relatively low and long periods of dry weather are possible. The summer monsoon runs from May-June to August-September. In this case, the sea air is transferred to the mainland and warm weather is observed with a relatively large amount of precipitation and fog. Autumn in Peter the Great Bay is the best time of the year - usually warm, dry, with a predominance of clear, sunny weather. Warm weather lasts in some years until the end of November. In general, the stable monsoon nature of the weather is often disturbed by intense cyclonic activity. The passage of cyclones is accompanied by an increase in cloud cover to continuous, heavy rainfall, reduced 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, on average, 145 mm falls. In some years, precipitation, comparable in quantity with monthly norms, can be of a volley, short-term nature and lead to natural disasters.
In the annual course of mean annual 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 regions to more continental ones. Short-term changes in pressure in the daily course reach 30-35 mb and are accompanied by sharp fluctuations in wind speed and direction. In fact, the recorded maximum pressure values in the Vladivostok area 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 Ussuriysky bays, the air temperature can drop to -37 °. The warmest month of the year is August, when the average monthly temperature rises to + 21 °.
During the winter monsoons, from October-November to March, prevail winds north and northwest directions. In spring, when the winter monsoon changes to the summer one, the winds are not very stable. Southeast winds prevail in the bay in summer. 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 tops of the Amur and Ussuriysk bays, the average monthly wind speed is 1 m / s, in bays and bays - 3-5 m / s. Storms are mainly associated with cyclonic activity and are observed mainly during the cold season. The largest number days with a stormy wind is observed in December-January and is 9-16 per month. In the tops of the Amur and Ussuriisky bays, storm winds are not observed every year.
They come to the Gulf of Peter the Great typhoons, originating in tropical latitudes, in the region of the Philippine Islands. About 16% of all tropical cyclones originating there emerge on the Sea of Japan and the Primorsky Territory mainly in August-September. The paths of their movement are very diverse, but none of them follows the trajectory of the other exactly. If the typhoon does not enter the Peter the Great Gulf and is still observed only in the southern part of the Sea of Japan, it still affects the weather in this area: there are heavy rains and the wind intensifies to a stormy one.
Hydrological characteristics
Horizontal temperature distribution
Surface water temperatures experience significant seasonal variability, mainly due to the interaction of the surface layer with the atmosphere. In the 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 more high temperatures than Ussuriysk. In summer, the waters of the bay warm up well. At this time, in the tops of the Amur and Ussuriysky bays, it reaches 24-26 °, in America Gulf - 18 °, and in the open part of the bay - 17 °. In autumn, the temperature drops to 10-14 ° in secondary bays and to 8-9 ° in the open part. In winter, the entire mass of water is cooled, its temperature ranges from 0 to -1.9 °. Subzero temperatures occur throughout the shallow waters, as well as in secondary bays. The position of the 0 ° isotherm roughly 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 values of temperature. With increasing depth, the range of temperature changes decreases and already at a depth of 50 m does not exceed 3 °, and at depths of more than 70 meters, seasonal changes are almost not manifested.
Vertical temperature distribution
In the warm period of the year (April-November), a monotonic decrease in temperature with depth is observed. 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, the cold deep waters rise in shallow water, and at a depth of 40 m, a second layer of temperature jump is formed. In December, both layers of the temperature jump under the influence of convection are destroyed, and throughout the winter period (from December to March) the temperature remains constant 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 distribution and variability of salinity. The water in some coastal areas of the bay is freshened to brackish, and in open areas it is close to the salinity of the adjacent part of the sea. The annual salinity variation 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 summit of the Amur Bay, where they are 28 ‰. At the top of the Ussuri Bay, salinity is 32.5 ‰, and in the rest of the water area it rises to -33-34 ‰. In summer, the surface layer undergoes the greatest freshening. At the top 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 the spring one. In winter, the 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, waters of high density are formed with a temperature of less than -1.5 °, and a salinity of 34.2-34.7 ‰. In extreme ice years, high-density waters, spreading at the bottom, reach the shelf edge, slide down the slope and ventilate the deep sea layers.
Water masses
In the winter season, in the Peter the Great Bay, the water characteristics within the entire stratum correspond to the deep water mass of the Sea of Japan (temperature is less than 1 °, salinity is about 34 ‰). In the bottom 20-meter layer during this period of time, a water mass of increased density is released with a low (up to –1.9 °) temperature and high (up to 34.8 ‰) salinity, 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 stratifies. In coastal areas, especially in intake areas fresh water estuarine water mass with low (on average 25 ‰) salinity, high (on average 20 °) temperature in the summer season and a depth of distribution up to 5-7 meters is released from the mouths of rivers. The water masses of the open areas of the bay are divided by seasonal thermocline into: superficial coastal, which is extremely spreading from the surface to a depth of 40 m and in summer has indices: temperature - 17-22 °, salinity - 30-33 ‰; subsurface - to a depth of 70 m with a temperature of 2-16 ° and a salinity of 33.5-34.0 ‰; and deep shelf - below the horizon 70 m to the bottom with a temperature of 1-2 ° and a salinity of about 34 ‰.
Currents
The circulation of waters 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 Primorskoe Current is clearly traced, which spreads in the southwestern direction at a speed of 10-15 cm / s. In the southwestern part of the bay, it turns to the south and gives rise to the North Korean Current, which is most pronounced at the 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 forms in the Ussuriysky bay, and a cyclonic one in the Amursky. Wind, tidal phenomena and the runoff of the Razdolnaya River (in the Amur Bay) cause a significant restructuring of the current field. The diagrams of the main components of the total currents of the Amursky and Ussuriysky bays, given in the atlas, show that the greatest contribution is made by wind currents, which in the winter season increase the anticyclonic circulation in the Ussuriysky Bay, and in the summer change it to cyclonic. When cyclones pass, 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 Posiet, Ussuriisky and America bays. It runs around the bay in less than one hour. Time of arrival full of water the semidiurnal tide is slowed down in closed bays and secondary bays separated by islands and peninsulas. The maximum possible tidal value (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 north-western region, where the maximum level is slightly higher than 50 cm, and least of all - in the Ussuriysky Bay and the strait between about. Putyatin and the mainland (the tide is 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 interfere with regular navigation throughout the year. In the bay, ice occurs in the winter season in the form of fast ice and drifting ice. Ice formation begins in mid-November in the bays of the Amur Bay. At the end of December, most of the bays of the Amursky and partly Ussuriysky bays are completely covered with ice. Drifting ice is observed in the open part of the sea. The ice cover reaches its maximum development in late January - mid-February. Since the end of February, the ice situation has eased, and in the first half of April, the entire water area of the bay is usually completely ice-free. In severe winters, especially in the first ten days of February, the ice reaches a high concentration, which makes it impossible for ships to sail without using an icebreaker.
Hydrochemical characteristics
In this version of the atlas, the hydrochemical characteristics are presented in the form of distribution maps at different horizons of mean long-term values of dissolved oxygen (ml / l), phosphates (μM), nitrates (μM), silicates (μM) and chlorophyll (μg / l) for winter and spring. , summer and autumn without further description. The source of data used (WOA "98) defines the time frames for hydrological seasons as follows: Winter: January-March Spring: April-June Summer: July-September Autumn: October-December.
Hydrological and acoustic characteristics
The main changes in the values of the speed of sound, both seasonal and spatial, occur in the 0-500 m layer.The difference in the values of the speed of sound in the same season at the sea surface reaches 40-50 m / s, and at a depth of 500 m - 5 m / with. The maximum values are noted in the southern and southeastern parts of the sea, and the minimum - 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 southwest to northeast through the central part of the sea. Here, in the 0-200 m layer, the maximum horizontal gradients of the sound speed are observed at any time of the year (from 0.2 s‾¹ in summer to 0.5 s‾¹ in winter). In this case, the maximum changes in the values of the speed of sound along the horizontal are observed in summer at a depth of 100 m.
The vertical distribution of the speed of sound in the southern and southeastern parts of the sea can be distinguished:
- the upper homogeneous layer, the thickness of which varies from 50 to 150 m during the year, with the sound speed values exceeding 1490-1500 m / s;
- a layer of a jump in the values of the speed of sound with large negative gradients (on average 0.2-0.4 s‾¹), spreading to a depth of 300 m;
- layer 300-600 m with minimum values (and gradients) of the speed of sound;
- 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. NS. drops to 600 m. The sound channel extends from the surface to the bottom.
In the northern and northwestern part of the sea, a homogeneous layer, but with minimum values of the speed of sound (less than 1455 m / s), is formed in winter and is associated with winter convection. The layer thickness can reach 600 m, and a surface sound channel is formed. In the rest of the year, changes in the speed of sound with depth are characterized by negative gradients increasing from spring to autumn to 0.5-0.8 s constant gradient value. The axis of the SZK with the minimum values of the speed of sound 1455-1460 m / s in this part of the sea comes to the surface in winter, and from spring to autumn it gradually sinks to a depth of 200-300 m.When moving to the south in the area of the front, the axis of the SZK 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 is determined only by the depth of the place.
