What is the South China Sea. What is the sea in Vietnam? South China - the best sea off the coast of Vietnam
China is the largest state in Asia. In terms of area, it is second only to Russia and Canada. And it would be strange if it did not have access to the sea.
And he really is. China, in addition to two straits, Korean and Taiwan, is washed by three seas at once:
East China;
South China.
All the seas of China are of a semi-closed type, surrounded by the mainland on one side, and belong to the basin Pacific Ocean from which they are separated by islands. At the same time, the total length of the coastline is 12 thousand kilometers, if you do not take into account the islands, the number of which reaches 3.5 thousand.
Yellow Sea
The Yellow Sea in China got its name from the fact that periodically its waters turn yellow. The coloration appears more in spring and summer, when rivers, including the Huang He, carry a huge amount of sand and silt from the continent. Another phenomenon of these waters is that they "bloom". The secret is in green algae that grow several kilometers from the coast. This leads to the death of fish and other animals.
The climate here is quite mild. One of the most famous beach resorts coast of the Yellow Sea - Qingdao, which is sometimes called "Eastern Switzerland". It attracts tourists with numerous beaches with fine white sand and amazingly clear coastal waters.
On the shores of the Yellow Sea, on the southern ledge of the Liaodong Peninsula, the city of Dalian was built. It used to be Russian and was called "Far". There are also very beautiful beaches and parks. They also come here to heal and relax.
South China Sea
It is a pity that many Russians do not know what seas are in China. But wonderful holiday offers the coast of the South China Sea. One of the most popular islands it has Hainan. Clear sea water, healthy air, a lot of greenery - this is what every tourist can enjoy here. bathe in sea waves you can even at the peak of the calendar winter - in January. And not only swim, but also go diving, surfing, yachting. The water temperature remains quite comfortable all year round. Also in the waters of the South China Sea, you can indulge yourself with a traditional Russian hobby - fishing.
East China Sea
This sea is much deeper than the Yellow Sea, on average, from the surface of the water to the bottom, there are 349 meters. It has a more severe character than other seas in China. From May to October, several times a year, typhoons occur here, causing very severe storms. Marine vegetation near the coast is rather poor. However, dolphins, sharks and even whales are found in these waters. The sea is rich in commercial fish. Tuna, flounder, sardine, mackerel, mullet, eels, herring are found in abundance in it, which successfully share the living environment with crabs, lobsters, sea cucumbers - exquisite delicacies.
Asking what kind of sea is in Vietnam, any person by no means betrays his ignorance. On the contrary, it shows interest in one of the geographical problems. At first glance, the answer is obvious - Vietnam washes the South China Sea in the east of the Pacific Ocean. And what basin does the Sinai Gulf in the southwest of the country belong to? It turns out that scientists have been deciding for a long time how to draw the border between the two parts of the oceans south of the peninsulas of Indochina and Malacca.
What is the sea in Vietnam?
In the east of the Pacific Ocean there are many ledges of land and islands that limit the water areas that have received their names. The archipelagos separate the large South China Sea from the basin. On its shores there is a country with beautiful nature, ancient history and rich culture. This is Vietnam - a state whose coastline stretches for 3,000 km along the shelf of the South China Sea. Its coast is famous for its convenient bays, azure bays and dozens of kilometers of wonderful beaches.
As you move away from the coast, the relief of the territory of Vietnam rises. Near the coast, rocks rise from the water, reminiscent of famous mountains from James Cameron's Avatar. Answering the question “Is there a sea or an ocean in Vietnam?”, some features of the South China Sea should be clarified. It is semi-enclosed, surrounded by large and small islands, other seas. Behind the chain of the Philippine archipelago are the sea of the same name and deep sea trench, at the bottom of which Cameron visited. The famous American-Canadian director and producer also dived alone on board deep-sea vehicle in the Challenger Basin at the bottom of the Mariana Trench in the eastern Philippine Sea.
Bakbo Bay (Tonkinsky)
The South China Sea in the northwest deeply protrudes into the land. The length of this water area is 330 km, the depth reaches 82 m. To the east is the Leizhou Peninsula, to the south is Hainan Island, separated from the mainland by the strait of the same name. On different maps, such Vietnamese and Chinese names of the bay can be indicated: Vinbakbo, Vinhainam, Beibuvan, Tonkin. The last hydronym on the list comes from former name Hanoi - Tonkin. The term is sometimes applied to all of North Vietnam. The largest port city in Bakbo Bay is Haiphong. It happens that the question “What is the sea in Vietnam?” there are several different answers. The thing is that each of the many peoples in this basin gave its name to the water area.
Gulf of Thailand
Between Indochina and the Malacca Peninsula lies the Gulf of Thailand, which is sometimes referred to as the Indian Ocean basin. The abundance of seas, bays, bays and islands between Asia and Australia sometimes makes it difficult to accurately draw the boundaries between the two parts of the oceans. As the researchers note, the biggest problems arise when delimiting in the area Malay Archipelago. The fact is that geographers, biologists and oceanographers had different opinions on the question of the dividing line between the Indian and Pacific oceans.
Usually, the waters of the Gulf of Thailand and further southeast to the Java Sea are considered to be the boundary. Some researchers consider the Makassar Strait, which separates the islands of Kalimantan and Sulawesi, to be the boundary. Only to the question "What is the sea in Vietnam?" scientists give an unequivocal answer: "South China!" Other water areas washing the shores of the country are bays and straits.
South China - the best sea in Vietnam
The country's coastline abounds beautiful beaches strewn with silky sand. The depth of the South China Sea is impressive - about 5500 meters. Swimming near the coast is safe if you do not swim far. Salinity sea water- about 34 ppm, which corresponds to the average for the entire oceans. Even in winter, the sea off the coast of Vietnam is warm, its temperature is 20-22 °C. In summer, the water on the beaches heats up to 28-30 °C.
Hainan Island in the South China Sea is one of largest resorts pool. But this beautiful piece of land belongs to the territory of China. To the east, the depth of the water area increases, in the west it is shallower, and numerous coral structures come to the surface. Like everything Pacific coast monsoon climate prevails in Vietnam. Constant winds from the ocean bring heavy rainfall at the beginning of summer, sometimes there are typhoons. In winter, the monsoons blow in reverse direction from land to sea.
coral islands
South China is a calm sea in Vietnam. The water area is very beautiful, it looks unusual due to the numerous islands and different shades of water. Near the shore, azure and greenish colors predominate. As the depth increases, the bright emerald hue intensifies. The underwater world of coral buildings in the South China Sea surprises and amazes with its diversity. There are predatory fish - moray eel, stone fish and others, which bathers and divers should be wary of.
Holidays on the coast of Vietnam
The most important and most popular Vietnamese resorts: Ha Long Bay, Nha Trang, Phan Thiet. The coastline in the south-east of the country enjoys the favorable attention of tourists. Nha Trang is one of the most famous resorts where the sea is better in Vietnam - clean, gentle and warm. Here you can swim and sunbathe on well-maintained beaches with white and golden sand, improve your health. This is one of tourist centers countries, with big amount historical sights, beautiful nature, colorful national traditions.
This is a very large sea, its area is 3537 thousand square kilometers. In the southern part, the marine area is located on the continental shallow shelf, and only in the north can one find a deep-water basin (a depth of more than 4000 meters). Interestingly, in the South China Sea, surface water currents are seasonal, so they often change direction. Average tides in some places reach six meters. Since the sea is warm climate zone, then its temperature ranges from 20 to 29 degrees. What are useful?
The coast line is slightly indented, so they are mostly low-lying. The largest bays include Tonkin and Siam. The many rivers that flow into this sea include the Mekong, Hongha and Xijiang rivers. In the South China Sea a large number of small islands, a significant part of them are of coral origin. The seabed is silty-sandy or just sandy, in some places rocky and pebbly. If you go down to a great depth, then the bottom is muddy. Admire the .
Inhabitants of the South China Sea
Along with others south seas, undersea world The South China Sea is rich in a variety of aquatic life. Only here each species is present in small numbers. The rich flora includes algae. This sea is also inhabited by phytoplankton. Since the surface of the waters is poorly saturated with minerals and oxygen, organisms are supported and developed. The variety of coastal vegetation is impressive in many places.
It is not even worth starting to list the inhabitants of the coastal regions and shallow waters of the South China Sea. After all, there are more than one thousand species of fish in Tokin Bay alone. Therefore, if you try to count all the species of the inhabitants of this sea, you can get an impressive figure. First of all, it is worth noting mollusks of all stripes, a large number of aquatic worms, representatives of arthropods, snakes. Here you can see echinoderm inhabitants - these are serpentine, stars and sea urchins. Of course, the richness of the fish world is striking.
These areas mainly produce southern herring, tuna, conger eel, mackerel, sardines and croaker. In some areas, trepang and sea turtles. The largest fish in the South China Sea include: rays, tuna, moray eels, marlin, swordfish and sharks. In the waters of this sea are found different kinds predators, for example: bearded, spiny, reef, zebra, hammerhead and cat sharks. Of course, such a neighborhood of local residents and toothy predators sometimes leads to unpleasant consequences.
For this reason, when planning a vacation in the South China Sea, you should carefully read the description of all types of dangerous animals that you are likely to encounter. It is important to remember about safety measures and follow the instructions of the guides. Only in this case, you can enjoy all the sights of the South China Sea.
One of the most big seas The World Ocean - South China - is located in the western part of the tropical zone of the Pacific Ocean and is connected to it and adjacent seas by straits.
In the west, the sea is limited by the eastern coast of the Malay Peninsula and the Asian mainland. northern border runs from the northern tip of Taiwan to about. Haitandao. In the east, the Philippine Islands (Luzon, Palawan) and about. Kalimantan. The southern boundary runs along the uplift between the islands of Kalimantan and Sumatra (about 3° S).
Coast of the South China Sea
Sea area - 3537 thousand km 2, volume - 3623 thousand km 3, average depth - 1024 m, maximum depth - 5560 m.
The coastline of the sea (with the exception of some areas) is not very indented. Most large bays- Bakbo (Tonkinese) and Siamese. Large rivers flow into the sea: Xinjiang and Hongha (Red) in the north and Mekong in the south. Mekong - the most major river peninsula of Indochina. The area of its basin is about 1 million km 2, the length is 4500 km. At the exit to the sea, the river forms a branched delta, the width of the watercourses of which is from 2 to 20 km. During floods, the Mekong carries a large amount of suspended sediment (up to 250 g/m3) into the sea.
Island off the coast of Vietnam
Most large island- Hainan is located at the entrance to Bakbo Bay. In the open sea there are numerous groups of islands and individual small islands. coastal islands in most cases represent a continuation of the mainland mountain systems. At the same time, in the sea (especially in the eastern part), many islands are of coral origin.
Bottom relief
Large areas are distinguished in the relief of the seabed: shelf, continental slope South-East Asia, the slopes of the islands and the deep-water basin. The shelf reaches its greatest width in the northern part of the sea and in the southwest, and stretches in a narrow strip near Philippine Islands. The shelf zone with depths up to 200 m accounts for more than half of the sea area. The continental slope has a stepped character and extends to depths of 3000-3600 m, where it smoothly passes into the bottom of a deep-water basin, which occupies vast spaces in the northeastern part of the sea, with depths in individual depressions up to 5000-5400 m.
Bottom relief and currents (in summer) of the South China Sea
A steep ledge up to 1500 m high separates from the northern part of the sea the southern, very shallow, with a complex mountainous terrain, many islands, reefs and banks. Depths in the southern part of the sea do not exceed 200 m. The bays of Bakbo and Siam are also shallow, where depths up to 50-70 m predominate.
The South China Sea is characterized by active tectonic activity. Underwater earthquakes and volcanic eruptions often occur here, affecting changes in the bottom topography.
Halong Bay, Vietnam
Climate
Located in the tropical zone, between the equator and 25°N, the sea is characterized by a warm and humid monsoonal climate, with heavy rainfall and frequent typhoons.
The air temperature in February varies from 15° in the north to 25° in the south of the sea. In August, over the entire water area, the average temperature is 27-28 °.
From November to March, stable northeast winds of the winter monsoon dominate the sea. From May to September, southwesterly winds are observed, characteristic of the summer monsoon. The northeast monsoon is stronger and longer than the southwest monsoon.
During the northeast monsoon, the highest wind speed in the northern part of the sea reaches 16-18 m/s, in the central part - 12-14 m/s, and in the south - 13-15 m/s. During the southwest monsoon, there is a gradual decrease in wind speed from south to north. Light winds prevail for about half of this season.
The South China Sea is one of the areas of the World Ocean where tropical cyclones - typhoons - are regularly encountered. They sometimes form over the sea itself, but more often come from the western Pacific. On average, 10-11 typhoons are observed over the sea per year, with the largest number (up to 65%) occurring in the summer and autumn months. The duration of the stay of the typhoon over the sea is from 5 to 10-12 days.
In connection with the movements of the intratropical convergence zone, the position of the area of the most frequent occurrence of typhoons changes from summer to autumn. In summer, the greatest number of typhoons is formed north of 15°N, and in autumn, when the convergence shifts to the south, to the south of this parallel.
The features of the wind regime of the South China Sea determine the possibility of the development of strong wind waves. This is facilitated by the coincidence of the general direction of the extent of the sea with the direction of the monsoons. Thus, the duration and dispersal of the wind over the sea during the winter monsoon are sufficient for the excitement to reach full development at a certain wind speed. In the northern part of the sea, waves can have a length of 170 and a height of 7 m. The frequency of waves with a force of 5 points or more in winter is 20-30%.
IN summer season the excitement is relatively weak: the frequency of excitement with a force of 5 points is reduced to 10-20%, and in 60% of cases there is a slight swell or calm. However, even during the southwestern monsoon, the wave height in the northern part of the sea can reach up to 5-6 m or more.
In Bakbo Bay, with winds from the sea, the wave height is 3-4 m. Gulf of Thailand the development of waves is limited by a small wind acceleration and shallow depths, but with a westerly wind, waves develop up to 4-5 m.
The strongest excitement is observed during the passage of typhoons. When the wind speed reaches 50 m/s, the wave height increases to 7-8 m. During typhoons in the northern part of the sea and in Bakbo Bay, waves 8-9 m high were observed.
Water circulation and currents
Monsoon circulation is the main cause of seasonal sea level changes. The annual course of the level is in good agreement with the nature of the monsoon winds. On the western coast of the sea, the maximum level is observed from October to March, and the minimum - from June to August. On the eastern shores, near the Philippine Islands, the highest level is in August - September, and the lowest - in January - March. Range of annual level fluctuations in coastal areas sea - 50-80 cm.
In the sea, under the influence of monsoons, especially the northeast, long waves spread, causing surges. The largest surges are observed in western coasts seas, especially in the southwestern part, where the shelf is wide and the coastline is almost perpendicular to the direction of the northeast monsoon.
Strong surges of water cause typhoons. Storm surges from typhoons are most dangerous when they coincide with high tide water, especially at high tides. A dangerous surge during the passage of typhoons occurs on average once in three. The magnitude of storm surges off the coast of Vietnam during severe typhoons can exceed 2-2.5 m, and in the southern part of the coast of China, cases of storm surges almost 6 m high have been noted.
During storm surges, the area of maximum level rise is usually 5-15 km to the right along the coast from the place where the typhoon makes landfall. Storm surges can lead to the sudden intrusion of salt water into estuarine areas, causing great damage to the economy of coastal areas. In the Mekong Delta, for example, salt water can spread, flooding rice fields, at a distance of about 100 km from the sea, depending on the nature of the wind and tide.
The tides in the South China Sea are complex. Basically, regular and irregular diurnal tides prevail, only in the Taiwan Strait are semi-diurnal tides.
The main features of tidal phenomena in the sea are the large magnitude of the diurnal wave entering from the Pacific Ocean and the influence of the coast and bottom relief on the tide, causing an increase in its magnitude (for example, in areas with a wide shelf).
The tide in the sea varies from 50 cm to 6 m or more (in the Taiwan Strait). On the coast of Vietnam, the highest tides (3-4.5 m) are observed in northern regions. In the central part of the coast, the height of the tides decreases to 1.2-1.6 m, and in the south it again increases to 2.1-4.2 m. The velocities of tidal currents vary from 10 to 150 cm/s and more.
The influence of tides in rivers affects a considerable distance from the sea. The limits of tidal wave propagation are about 150-180 km for the Red River and about 350-400 km for the Mekong system. The speed of the tidal wave on different rivers varies from 15 to 25 km/h.
The impact of typhoons, monsoons, and tides greatly complicates the hydrological conditions in the mouth areas of the rivers flowing into the South China Sea.
Surface circulation in the sea and its seasonal variability are in full accordance with the change of monsoons. At the same time, at times, the general circulation pattern is disturbed due to strong local winds. Thus, significant currents can develop during the passage of typhoons.
From November to February, under the influence of northeast winds, the waters of the North Trade Wind Current from the Pacific Ocean through the Bashi Strait enter the South China Sea, where they merge with the current coming from the Taiwan Strait. The combined stream moves along about. Hainan to the coast of Vietnam and further south and southwest to southern part seas. At the same time, a western intensification of the current is noted - off the coast of Vietnam, its speeds reach 100 cm/s. A countercurrent develops in the middle of the sea, reaching Luzon, where it merges with the main current. In the central part of the sea, a cyclonic gyre is formed. A small amount of water enters the South China Sea from the Sulu Sea and mixes with the main current. Along the coast of Kalimantan, a very weak current moves to the southwest.
In April, the entire system of currents characteristic of the northeast monsoon breaks up into two large cyclonic gyres, one of which is located in the northeast part of the sea, and the other is located southeast of the coast of Vietnam. The inflow of water from the Sulu Sea and outflow through the Taiwan Strait is noted. A weak current also goes to the Java Sea.
From June to August, with the greatest development of the southwest monsoon, the current enters the South China Sea through the Karimata Strait and moves northward along the Malay Peninsula and further along the coast of Vietnam in a wide steady stream. Near the parallel 11 ° N part of the flow turns to the east and forms a countercurrent associated with the western intensification of the main current. The other part of the stream continues to move along the coast of Vietnam to the north and northeast and exits the sea through the Vashi and Taiwan straits. An anticyclonic gyre forms in the center of the southern part of the sea. In the eastern part of the sea, the currents are unstable. Along the islands of Kalimantan and Palawan, there is a weak flow to the northeast, part of which enters the Sulu Sea north of Palawan.
Current velocities in the winter season are usually higher than in summer and reach 70-100 cm/s, and sometimes reach 200 cm/s during typhoons.
The currents in the bays of Bakbo and Siam are complex due to shallow water and the influence of the relief of the coast and bottom. However, in autumn and winter the current is mainly cyclonic, while in the spring and summer months it is anticyclonic.
The physiographic and hydrometeorological conditions of the South China Sea are such that three types of water circulation develop in it:
Surface monsoon current, which flows through the sea as a whole and is strongest in the western part of the sea;
Horizontal circulation caused by transverse wind ripples in the sea. It manifests itself mainly during the northeast monsoon, when a countercurrent is observed in the eastern part of the sea, going to the north;
Vertical circulation caused by the accumulation of water in the direction of the monsoon. It causes oppositely directed transport in the surface and deep layers, as well as vertical displacements of water layers. This circulation is developed during both monsoon seasons, but stronger during the northeast monsoon.
All types of circulation are interconnected and generally provide an active exchange in the water column of the sea.
The water exchange of the sea with adjacent water areas is very significantly limited by the depths of the straits. The Taiwan Strait, which connects the South China Sea with the East China Sea, has a width of about 180 km in the northern part, and a maximum depth of 70 m. The main exchange of deep waters between the ocean and South China Sea It is carried out through the Vashi Strait between the islands of Taiwan and Luzon, the depths in the trench of which reach up to 2500 m. In the east, through the Mindoro Strait (with a threshold depth of 450 m) and Balabak, the South China Sea is connected to the Sulu Sea, but water exchange with it is negligible. In the south, the South China Sea communicates with the Yavan Sea through the shallow straits of Karimata and Gelas (with depths up to 40 m), which limits water exchange only to the upper layers. The Strait of Malacca connects the South China Sea with the Andaman Indian Ocean. In the narrowest part, the strait is 30 km wide and about 30 m deep.
Water temperature and salinity
In the structure of the sea waters, an upper homogeneous layer and a well-defined temperature jump layer below it are clearly distinguished. In the northern and central parts of the sea, these layers are subject to significant seasonal fluctuations. Below 200 m, thermohaline characteristics react weakly to changes in external conditions.
Annual changes in water temperature on the sea surface increase significantly towards the north. It is related to the flow cold water through the Taiwan Strait during the winter monsoon, and also due to the fact that during this season in the northern regions, evaporation and heat transfer from the sea surface increase. The range of annual temperature fluctuations off the southwestern coast of Vietnam, equal to 4°, increases to 10° near Hong Kong and to 14° in the Taiwan Strait. The surface water temperature in February rises from 18° in the northern part of the sea to 27° in the south. In summer, the temperature field is uniform, and in most of the water area on the surface it is about 29°.
Seasonal features of temperature distribution in the upper layer of the sea are associated with monsoon circulation. During the winter, under the influence of northeast winds, the upper layer of water is transferred to the south in the coastal zone. In this case, the thickness of the water layer above the thermocline increases to 70-90 m, and near the coast it can reach up to 150 m. The shock layer in winter is less pronounced than in summer. Its thickness is 70-90 m, and the temperature in it drops from 26 to 12 °.
The summer monsoon winds develop a northern current that passes through the entire sea and carries surface water out of it. For this reason, the temperature jump layer rises closer to the surface, which is especially noticeable near the coast, where the temperature of the surface layer is below 28°. The greatest rise of deep waters to the surface occurs in the middle of summer, seaward of the southern part of the Indochina Peninsula. The thickness of the quasi-homogeneous layer in summer is 30-40 m, and the thickness of the jump layer is 120-140 m. The temperature in the thermocline drops from 29 to 12°. On the horizon of 400 m the temperature in the sea is about 10° almost everywhere.
In the southern, shallow part of the sea, the temperature remains uniform from the surface to the bottom in large areas.
Salinity distribution in surface layer sea, as well as temperature, depends on the monsoon circulation. In addition, salinity is influenced by a large amount of precipitation, and in coastal areas - by river runoff.
in winter in northern part sea from the ocean comes water with a salinity of 34.5‰. During this season, the salinity in the upper layer of the sea also slightly increases due to intensive evaporation (by about 0.3‰). The language of the waters of such salinity, capturing coastal zone, extends to the south; salinity gradually decreases and does not exceed 32‰ near the southern boundary of the sea. The lower salinity in the eastern part of the sea is associated with the presence of a countercurrent to the north.
In the western part of the sea, salinity decreases to 30.5-31‰ in summer due to an increase in the inflow of the Mekong and other rivers and the spread of desalinated water to the north by a steady coastal current. In the eastern part of the sea, salinity is higher due to weak south current. In the south, during the summer rainy season, salinity decreases by about 0.7‰.
The central part of the sea is filled with waters with different salinity. During the winter monsoon, water with oceanic salinity is transported along the coast of Vietnam to the south, and in the central part of the sea, the countercurrent brings less salt water to the northeast. During the summer monsoon, water with low salinity moves along the coast of Vietnam to the north, and in the central part of the sea, a countercurrent carries more saline water to the southeast. The average monthly salinity on the surface in the northern part of the sea varies from 33.9‰ in February - March to 33.3‰ in September, and in the southern part - from 32.6‰ in March - April to 31.9‰ in August.
The water of the South China Sea, which has a relatively high salinity, is transported through the Malacca Strait during the northeast monsoon, and water with low salinity due to the influence of the Sumatra rivers during the southwest monsoon.
The salinity jump layer in the sea is formed by subtropical bottom water characterized by a salinity maximum. It is formed in the zone of trade winds, where the highest salinity is observed on the surface. The depth of the core of this water increases from 150 m at the entrance to the sea to more than 175 m in the sea. In the region of the Vash Strait, the salinity in the maximum layer is 34.9‰, the temperature is 23°C, and the oxygen content is 4.5 ml/l. As we move southwest, the salinity decreases when mixed with the overlying water to 34.5‰, the temperature and the amount of oxygen also decrease. In the southernmost part of the sea, the salinity maximum is no longer distinguished, the temperature of the subtropical lower water is about 15 °, and the oxygen content is less than 2.5 ml / l.
A remarkable feature is the oxygen minimum in the lower part of the jump layer, below the core of the salinity maximum. The oxygen content in the minimum layer is 1.4-2 ml/l, and the location depth is about 200 m, which corresponds well to the dynamic boundary between subtropical lower and intermediate water. Due to the fact that the oxygen content is higher in the upper layer of intermediate water, an oxygen inversion is formed, to the west of about. Luzon reaching 0.9 ml / l.
The reduced salinity northern intermediate water mass in the South China Sea is an intermediate water formed in Antarctica. The depth of the minimum salinity layer decreases from 500 m in the Vash Strait to less than 400 m in the sea itself, and the salinity in the core increases from 34.3 to 34.5‰. The temperature of the northern intermediate water is from 7.5 to 9.5°. The amount of oxygen in the layer of minimum salinity decreases from 2.5 ml/l in the area of the strait to 1.5 ml/l in the south of the sea.
The deep waters of the South China Sea are very homogeneous in structure. In the water column, at depths above 2000 m, the temperature remains within the range of 2.32-2.46 °, and salinity - 34.5-34.68‰. The values of these characteristics rule out the possibility of formation of deep waters in the sea area. Studies have found that the waters filling the basin of the South China Sea are the deep waters of the Philippine Sea, which have the same characteristics. These waters enter the South China Sea through three deep water passages in the Bashi Strait.
A rather high oxygen content (2.5 ml/l) at a depth slightly below the threshold of the strait (about 2500 m) indicates relatively good ventilation of the South China Sea deep-water basin.
Economic importance
The South China Sea is rich in fish. There are up to 900 species of fish here. The fish species composition of Bakbo Bay is of interest, as it is typical of the ichthyofauna of the coastal waters of the entire northwestern part of the South China Sea. The bulk of the ichthyofauna of Bakbo Bay are species that are widespread in the tropical zone of the Pacific and Indian Oceans(about 60%), as well as warm-water species of temperate latitudes. In total, up to 750 species of fish live in the bay.
The number of commercial fish species in the South China Sea is not very large (about 20 species). Bottom fish play the main role in the fishery. These are reef perch, threadfins, crucian carp, croaker, horse mackerel, stone perch, eel, etc. Of the bottom fish, saurid, red mullet, flounder, sea catfish are more common in catches; sardine, herring, horse mackerel, hammerhead fish are most important among pelagic fish , numerous gray sharks, bonito, etc. Small tuna, southern mackerel, flying fish are of commercial importance.
The ecological conditions of the sea in recent decades have deteriorated significantly due to the pollution of the water area with oil films. Oil lumps are common in the surface 10-meter water layer not only in the coastal, but also in the open part of the sea.
The South China Sea in Vietnam is called East Sea and, rarely, the Vietnam Sea. It is one of the marginal seas of the Western Pacific Ocean. It has essential for Vietnam and neighboring countries. This is due to the fact that it is the only sea washing Vietnam and has a large amount of bio-resources and hydrocarbon deposits. In addition, it forms the climate of the Indochinese Peninsula and is an important transport corridor.
The sea near the Vietnamese city of Cam Ranh south of Nha Trang
Geographical position
On the western side, the South China Sea is limited by the line of the Asian mainland. On this side, China, Vietnam, Cambodia, Thailand, Malaysia and Singapore have a coastline. From the east it is limited by many islands. Taiwan, the Philippines, Malaysia, Brunei and Indonesia have coasts here. It refers to semi-enclosed seas, because there are many straits between the islands, including wide ones.
Fishermen of the South China Sea (Vung Tau)
From north to south, the sea extends from the Tropic of Capricorn to the equator and even extends a little into the southern hemisphere. From west to east, its length is not so great. From the northeastern to the southwestern extremity of the sea runs the Main Sea Route - perhaps the most intense of the sea routes, with the exception of straits and channels.
The largest bays of the South China Sea are Tonkin and Siam, which is sometimes called Thailand.
Inside the sea there is only one large island - Hainan. Most of the rest of the islands are of coral origin. The islands lying on the sides of the Main Sea Route have a different structure. The Paracel Islands and the Spratly Islands are low, made of coral sand and covered with stunted vegetation.
Vietnam occupies an advantageous central position in the South China Sea and has the most great length coast.
natural characteristics
The area of the South China Sea is 3,537,289 km². Max Depth- 5560 m. However, approximately two thirds of the sea area has a depth of less than two hundred meters. Deep water is the northeastern part. Typhoons are frequent in summer and autumn. The tides are irregular, diurnal and semidiurnal, up to 4 m.
The water temperature on the surface in January is from 14 °С in the north to 27 °С in the south, in August it reaches 28-30 °С over the entire area. The average salinity of water is 32-34 ‰.
The climate in the South China Sea and adjacent territories is monsoonal. This means that air masses during the wet season move from the sea to the mainland, and during the dry season - from the depths of the mainland to the sea. By temperature characteristics the sea is located mainly in the subtropical, tropical, subequatorial zones, and also a little - in the temperate and equatorial zones.
Typhoons pose a great danger to navigation and to the economy and life of people on land. Most intensively they pass through it in October-November.
The sea is rich biological resources. Commercial fish - tuna, herring, sardines, some types of sharks, sole and others. In addition to fish, squids, crabs, shrimps, lobsters (lobsters) are caught. On the coastal farms, various types of shellfish are grown, as well as shrimp.
Sea of Vietnam
Sometimes the South China Sea is called the Sea of Vietnam. This is because its mainland coastline is the longest.
For many centuries, the Vietnamese poorly mastered their sea. Conducted coastal fishing for seafood and that was it. There was even a saying: "The Vietnamese stand with their backs to the sea." Among the Vietnamese, it is not very common and the rest is not the sea, although for the majority it is always nearby.
Under the Nguyen dynasty, a sea expedition was undertaken to the Pracel Islands, and from that time they began to be considered the territories of Vietnam.
After the August Revolution, the "Sea of Vietnam" began to be developed more actively. A fishing fleet appeared, albeit small, but numerous. His ships were already far from the shore.
The navy also consisted of small boats for various purposes. At present, the "Sea of Vietnam" is being plied by medium-sized naval vessels and several of the latest Russian-built submarines.
The tonnage of the merchant fleet is significant. Most of the ships are built in Vietnam.
Economic importance
IN Lately The main economic factor of the South China Sea is the production of oil and gas on its shelf. It is carried out by several countries. China is especially interested in the production of hydrocarbons because of the instability of the situation in the Persian Gulf, from where it receives most of its fuel resources.
Since ancient times, the South China Sea has been a source of fish and other seafood for the coastal population. In modern conditions, on numerous farms in coastal waters, mollusks and arthropods are grown and exported in frozen form to many countries of the world.
Main sea route The South China Sea transports a huge amount of cargo. On it from China, South Korea, Japan and Taiwan to the countries of Europe, Asia and Africa go manufactured goods, rice and seafood. In the opposite direction, oil (half of the world's production) is transported from the Persian Gulf, and manufactured goods from Europe.
holiday seasons
In countries washed by the South China Sea, a large number of foreign tourists. Due to the monsoon climate, not all months of the year are equal in terms of comfort.
IN southern China and northern Vietnam, temperature seasonality is felt, so the period from November to March for beach holiday does not fit. The rest of the coast, approximately south of Da Nang, is comfortable year-round in terms of air and water temperature. But due to the monsoon factor, there is an increased amount of precipitation for several months.
In Malaysia, the wet season in the Malacca Peninsula is summer. Borneo has a wet winter season.
In Cambodia, the wet season lasts from May-June to October.
In Thailand, from late April to mid-November, the summer wet monsoon dominates.
In the Philippines, the wet season is from July to December.
The best holiday season along much of Vietnam's South China Sea coast is from March to May, though Russian tourists traditionally go there in autumn and winter. This is probably due to the fact that beach destinations to Europe and the Middle East at this time are unattractive.
History and modernity
For a long time until the 19th century, the South China Sea was quite peaceful, except for local pirates. The maritime trade routes between China, India and other countries passed through the sea. With the development of the fleet in Europe, European ships began to walk on it for Chinese goods.
Since the 19th century, the countries of Southeast Asia, which are washed by the South China Sea, began to fall into colonial dependence on Great Britain, France and smaller European countries.
During World War II, US and British naval operations against Japan were carried out in the sea and on the coast. During the Vietnam War, the Americans kept a significant part of their 7th Fleet by the sea, primarily for the bombing of northern Vietnam.
At present, the main core of the political and economic struggle of the neighboring countries is the dispute over the Spratly Islands in connection with deposits of oil and gas off their coasts.
