Black sea currents map cold and warm currents. All about Crimea Black sea currents warm and cold map

Main current of the Black Sea, the most extensive is called - "Main Black Sea current"... Having a counterclockwise direction, it extends over the entire perimeter of the sea. This current forms two rings, in the scientific community referred to as "Glasses of Knipovich". Knipovich is the first hydrologist to notice and describe such a phenomenon in his works. The movement, as well as its characteristic directionality, arises due to the acceleration transmitted to the water from the rotation of the Earth. "Coriolis force"- the scientific name for such an effect in physics.

An additional significant effect on water flows is both the strength of the wind and its direction, because the Black Sea's water area is relatively small in area. Considering these factors, one can speak of a strong variability of the main Black Sea current. It happens that its severity drops sharply in comparison with other, smaller currents. And at other times, the speed of its flow can reach 100 cm per second.

The coastal zones of the Black Sea are the place of frequent occurrence of eddies directed in the direction opposite to the main Black Sea current. This anticyclonic gyres, which are most characteristic of the Anatolian and Caucasian coasts. Coastal currents at the surface of the water are generally wind driven. Their direction can change during the day.

Tyagun or reverse current in the Black Sea

One of the types of such currents is called "Pull"... The place of its appearance is the gentle coastline with sand beaches, formed during a storm. After hitting the shore, the water recedes unevenly, and flows in strong streams along the channels formed in the sandy bottom. Such jets are very dangerous for swimmers, because they carry away very far from the shore. Tyagun is rare in the Black Sea.

BLACK SEA COLOR

The Black Sea "is not the bluest in the world" (Sargasso Sea, some areas of the Indian Ocean) - even in the Red Sea the water is blue than in the Black Sea. The color of water depends on the scattering of the rays of the solar spectrum by water particles and impurities.
Beams different colors have different wavelengths, red - long-wavelengths are absorbed in the surface layer; blue - shortwave - are reflected and fall into the eye. Near the coast, where there are many impurities, green and yellow rays are reflected.
Also, the color of the water depends on the amount of suspended particles. There are more of them in the Azov Sea than in the Black Sea, so the water in the Azov Sea is greenish-brown, and in the Black - greenish-blue.
The transparency of water is determined by lowering to a depth of a standard white disc with a diameter of 30 centimeters, the depth at which this disc is hidden from view and is called the transparency of water. The largest - 27 meters, in the eastern part - in the summer, the smallest 2-3 meters - in the north-western part - in the spring. At a depth of 25 meters, the illumination is 1-4 percent of the illumination on the surface.

BLACK SEA CURRENTS

1. Weak, the speed rarely exceeds 0.5 meters per second, the reasons for them - the flow of rivers and the effects of winds. Under the influence of river runoff and under the influence of the earth's rotation force, it deviates to the right by 90 degrees (to the northern hemisphere) and goes counterclockwise along the banks. The main stream of currents has a width of 40-60 kilometers and passes at a distance of 3-7 kilometers from the coast.
2. Separate clockwise gyres are formed in the bays, their speed is 0.5 meters per second.
3. In the central part of the sea - zones of calm, there are 2 rings: in the eastern and western half.
4. Winds form temporary currents.

5. In the Bosphorus, Admiral Makarov established 2 currents:
a) surface - carrying desalinated water from the Black Sea to the Marmara Sea, at a speed of 1.5 meters per second;
b) deep - carrying dense saline to the Black, a speed of 0.75 meters per second.

BLACK SEA WATER POLLUTION

a) semi-closed, weak exchange of waters with the ocean.
b) lack of vertical movement of water.
c) oil (oil pouring out; ballast water gives the greatest amount of oil; after unloading oil, tanker tanks are filled with ballast - sea ​​water, and before reloading it is poured into the sea; oil has a neuroparalytic effect on marine organisms: fish - 15 milligrams of oil per 1 liter of water, mussels - 40 milligrams.
d) discharge of untreated waste water into the sea. Purification systems are needed, especially water, plastics and other synthetic substances.

The material used for the article:
Encyclopedic Dictionary of Brockhaus and Efron: In 86 volumes - St. Petersburg, 1890-1907.
Agbunov M.V. Antique sailing of the Black Sea. Academy of Sciences of the USSR. Science, Moscow, 1987.
Kuzminskaya G. Black Sea. Krasnodar 1977.
Beasts of the Black Sea. Simferopol: Tavria, 1996.
Wikipedia

In the Black Sea there is Main Black Sea Current(Rim Current) - it is directed counterclockwise along the entire perimeter of the sea, forming two noticeable rings ("Knipovich glasses", named after one of the hydrologists who described these currents). This movement of water and its direction is based on the acceleration imparted to water by the rotation of the Earth - Coriolis force. True, in such a relatively small area as the Black Sea, the direction and strength of the wind are of no less importance. Therefore, the Rim Current is very changeable, sometimes it becomes poorly distinguishable against the background of currents of a smaller scale, and sometimes - the speed of its jet reaches 100 cm / s.

In the coastal waters of the Black Sea, eddies of the opposite Rim Current direction are formed - anticyclonic gyres, they are especially pronounced near the Caucasian and Anatolian coasts.

Local alongshore currents in the surface water layer are usually determined by the wind, their direction can change even during the day.

A special kind of local coastal current - tyagun- is formed near gentle sandy shores during strong sea waves: the water running onto the shore recedes back not evenly, but along the channels formed in the sandy bottom. It is dangerous to get into the stream of such a current - despite the efforts of the swimmer, he can be carried away from the shore; to get out, you have to swim not directly to the shore, but obliquely.

Vertical currents: the rise of waters from the depth - upwelling, most often occurs when drive away coastal surface waters from the coast by strong winds from the coast; at the same time, water rises from the depth to replace the surface water driven off into the sea. Since the water in the depths is colder than the surface water heated by the sun, as a result of the displacement, the water near the coast becomes colder. The drainage of water off the Caucasian coast of the Black Sea, caused by a strong northeasterly wind (this wind is called bora here), is so powerful that the sea level near the coast can drop by forty centimeters per day.

In the oceans, upwellings arise when the Coriolis force (created by the movement of the Earth around its axis) acts on the masses of water carried by currents in the meridional direction (from the poles to the equator) along the coasts of the continents: Peruvian current and Peruvian upwelling (the most powerful in the world) off the Pacific coast South America, Benguela Current and Benguela upwelling off the east coast of South Africa .

Upwellings lift water enriched with biogenic minerals (salt ions containing nitrogen, phosphorus, silicon) into the surface, illuminated layer of the ocean (or sea), which are necessary for the growth and reproduction of phytoplankton microalgae - the basis of life in the sea. Therefore, upwelling areas are the most productive water areas - there are more plankton, and fish - and everything that is found in the ocean.

Surface currents of the Black Sea originate in estuaries big rivers and in the Kerch Strait. River waters, entering the sea, are deflected to the right by the Coriolis force. In the future, the direction of the currents is influenced by the wind and the configuration of the coast. In spring, when river runoff is at its maximum, it is the main cause of surface circulation in the sea. In autumn, when surface currents depend only on the wind, currents in the underlying layers can have a different direction.

Most of the river water flows into the northwestern part of the sea. Here the coastal current arises. Having collected the waters of the Dnieper, Southern Bug and Dniester, it reaches its true scale when it receives the Danube waters. Near the Romanian and Bulgarian shores, this current is directed to the south. To the east of Varna, where the Crimean current flows into it, a current is formed directed to the south, towards the Bosphorus. A few miles from the coast, where the axis of the current passes, it becomes the most powerful, the salinity is the smallest. From the axis of the current to the coast, salinity slightly increases, the speed of the current weakens, conditions appear for the occurrence of a countercurrent (directed to the north). Directly off the coast, depending on its configuration, there are local currents. Under the influence of the local river runoff, salinity here decreases. The currents adjacent to the coast are weak and are more strongly influenced by the winds. Overall, however, dominated by south current... Due to the seasonal change of winds and the influx of river waters, the southern current is most intense in winter and spring. In summer, when it weakens, the northern countercurrent is more pronounced. The latter also intensifies in the fall, sometimes even more significantly.

From the Bosphorus, the main part of the coastal current continues to move around Anatolia. The prevailing winds favor the easterly direction of the current. From Cape Kerempe, one stream of the current deviates northward to the Crimea, the other continues to move eastward, capturing the runoff of Turkish rivers along the way.

Surface current is usually in southwest part of the sea forms a vortex, arising mainly under the influence of southeastern and northerly winds.

Near the shores of the Caucasus, the current prevails in the northwestern direction. In the area of ​​the Kerch Strait, it merges with the Azov Current. At the southeastern coast of Crimea, the current is divided. One branch, descending to the south, diverges with the current from Cape Kerempe, and in the Sinop region flows into the Anatolian current. Thus, the circle of the East Black Sea cyclonic circulation is closed. Another branch of the Azov Current from the Crimea is directed to the west and is divided into currents of the north-western direction (towards Odessa) and the south-western direction (towards Varna). The latter is called the Crimean Current, and when it merges with the “river current” created by the waters of the Dnieper, Southern Bug, Dniester and Danube, it closes the circle of the western Black Sea cyclonic circulation.

Under cyclonic surface currents Compensatory anticyclonic currents are often formed at a depth of 150-200 m. Such currents also exist near the mouths of large rivers. The speed of the current decreases towards the central regions of the sea.

In the central regions, there are practically no definitely directed currents; there is only a drift movement of water masses, which occurs under the influence of the wind.

With strong winds from the land, the outflow of surface waters from the coast and the rise of waters of the underlying layers is sometimes observed.

In case of strong winds from the sea, besides that there is roughness, the surface coastal current also intensifies, but insignificantly in all seasons, except for the winter one. In winter, the surge effect in combination with strong cooling of coastal water creates conditions for the formation of vertical circulation and lowering of water along the shelf slope to great depths.

Excitement. The intensity of the waves, the height of the waves and their speed depend on the speed of the wind, its duration and wave acceleration.

The maximum excitement near the Bulgarian coast, obviously, should be with the easterly winds, and the Caucasian - with the westerly. With a wind of 7-8 points, lasting two days, waves with a height of 7 m and a length of about 90 m should form near the Bulgarian shores. In fact, even with very strong storms, the maximum waves are less - due to the influence of coastal shallow water.

At the Caucasian coast, where there are significant depths, the waves are higher; Thus, in the Poti region, waves with a height of about 5 m were recorded, and in the Sochi region, during a strong storm on January 28-29, 1968, a wave with a height of 7 m with a period of 9-10 s was recorded.

Near the Bulgarian coast, waves of approximately this height were observed only on January 17-18, 1977 and October 18, 1979.

In the open sea, with a 5-7-point wind, the Black Sea wave has the following average values: a period of 6-7 s, a speed of 2.4-5 m / s, a length of 10-30 m and a height of 1.5-2.5 m. in rare "cases with strong storms, the height of the waves reaches 5-6 m," and the length is 70-80 m.

The impact force of the waves is very high. According to the record of a dynamometer installed on a breakwater in Tuapse, with a westerly wind of 4-5 points and a wave with a period of 11 s, the impact force was 5.7 tons per 1 m2.

The intensity of the excitement changes / according to the seasons - it is maximum in autumn and winter, and minimum - in ma? and June.

In the mode of excitement, diurnal changes are also observed. In most cases, the height of the waves in the afternoon is higher than in the morning. This is most pronounced in summer, when breeze circulation develops - in the afternoon the wave becomes 10 cm higher than in the morning. In winter, such differences are insignificant - on average 1 cm, and even at night the waves are higher than in the afternoon.

After the wind has stopped, the excitement does not subside immediately, the swell persists - gentle, smoothly moving waves. If a strong wind causes a surge in one part of the sea and a surge in another, level fluctuations occur, similar to the fluctuations of scales. These fluctuations are called seiches. They can also be caused by a sharp change in atmospheric pressure. The excitement that began on the surface of the sea penetrates into the deep layers and gradually, with depth, fades away. At the boundaries of layers differing in density, internal waves of large amplitude and length are formed. They cause rapid changes in temperature, salinity and other hydrological and hydrochemical parameters of water, most often at depths of 150-200 m.

Vertical exchange

Analyzing the data on the seasonal distribution of the stability of the layers, it can be noted that in winter, when conditions are favorable for maximum vertical mixing, even with strong storms, it is limited to the upper 100-meter layer; only occasionally, weakening, the mixing can penetrate to a depth of 150-200 m. Despite the strong winter cooling, the waters of the upper 200-m layer are less dense than the waters of the underlying more saline layers. As a result, winter vertical mixing in the Black Sea develops only up to a depth of 200 m. Below this horizon, vertical water exchange is difficult.

Main role in vertical water exchange between the 200-meter upper layer and the deep waters of the Black Sea, there is an inflow of the marble sea water. Many authors are of the opinion that its role is not so significant, since in a year from the Sea of ​​Marmara, approximately 1/2000 of the volume of the deep Black Sea waters That is, the marble-sea tributary completely replaces the deep waters in about 2000 years. However, such conclusions were made for the case when the salinity of the marble sea stream is about 35 and / oo. In fact, according to the Bulgarian scientists, the salinity of the lower Bosporus jet in most cases is about 24-25 - the sea waters are intensively mixed with the Black Sea waters, the salinity of which is about 18 ° / o- Consequently, less saline waters enter the deep layers of the Black Sea, but in a larger volume - not 229 km3 per year, but about 1000 km3. Thus, the complete renewal of deep water should occur in about 480 years. In reality, it will proceed faster due to the compensatory outflow of water, vertical mixing, under the influence of internal waves, turbulence, exothermic processes, the rise and fall of water in systems of cyclonic and anticyclonic currents and a number of other reasons.

Summer vacations on the Black Sea - this is what many Russians dream of during their working days. However, the southern beaches are fraught with dangers. Each tourist season Media reports of people who have died while swimming in shallow water. The main cause of such accidents is bottom currents. Locals call them drags because these streams of water can easily drag even experienced swimmers to the next world.

What the rips and pulls

The strength and speed of the wind have a great influence on the Black Sea currents. Under the influence of storms and other meteorological phenomena, the direction of water flows in this hydrological object is rapidly changing.

Group of scientists: A.G. Zatsepin, V.V. Kremenetsky, S.V. Stanichny and V.M. Burdyugov, representing the Moscow Institute of Oceanology named after P.P. Shirshova and the Sevastopol Marine Hydrophysical Institute, wrote scientific article“Basin circulation and mesoscale dynamics of the Black Sea under wind influence”. This scientific work was published in the collection " Contemporary problems dynamics of the ocean and atmosphere ”(Moscow, 2010 edition).

The authors of the study noted that, depending on the wind, the structure and intensity of the coastal current can repeatedly change from "jet" to "wave-vortex" regime of water circulation. And this is confirmed by the data of long-term observations.

The instability and variability of the Black Sea often leads to the formation of so-called rip currents in the coastal zone (rip current). As a result of the storm, waves appear near the gently sloping sandy beaches, which move not towards the coast, but, on the contrary, away from it. And swimmers caught in such rips or pulls cannot get to land in any way: the current nullifies all their efforts. In the end, exhausted and panicked people drown in shallow water, very close to the coast.

Such dangerous phenomena occur on many beaches, where the gently sloping bottom is framed by sandbanks and spits. Rips are often found in the Gulf of Mexico, the Pacific Islands, in the resorts of India, in the Mediterranean, Black and Azov seas, the inhabitants of the Far East also know about them.

Although the dimensions of the draft are usually small, it reaches 10-15 meters in width and no more than 100 meters in length, the speed of the current is quite high - up to 3 meters per second. So even a trained swimmer may not be able to cope with such a flow.

Vacationers should be careful. If some area of ​​the sea surface located next to the coast is noticeably different from the rest of the water area in terms of the color and nature of water movement, and white foam has formed on its surface, then it is absolutely impossible to climb into the water in this place.

How do they arise

Scientists argue about the reasons for the formation of drafts throughout the history of meteorological observations. Most experts believe that it is a matter of wind strength and speed. This point of view is shared, for example, by Natalya Balinets, a hydrologist of the Hydrometeorological Center of the Black Sea Fleet of the Russian Federation. Her article “Conditions for the occurrence of traction in the ports of the Black Sea” was published in the specialized journal “Ecological safety of coastal and shelf zones and integrated use of shelf resources” (No. 15 for 2007).

ON THE. Balinets called the rift current a particularly dangerous hydrometeorological phenomenon. After analyzing the conditions for the occurrence of tractors over a long period of observations, she determined what atmospheric processes precede them. It turned out that in almost 80% of cases, such currents arise as a result of storms formed by Mediterranean cyclones that came to the southwestern part of the Black Sea.

But the most powerful drafts arise in such a situation: “Above the northwestern, northern or central regions of the European territory of Russia is the center of a vast cyclone, its hollow covers the northern part of the Black Sea. An anticyclone or ridge extends over Turkey or the Balkans. Southerly winds prevail over the sea. "

As N.A. Balinets, in this case, the speed of storm winds can reach a special force, and the excitement of the water in some places is recorded at around five points. After such meteorological phenomena, in a seemingly calm water area, drafts appear.

Why are they dangerous

Tourists are killed on the Black Sea every year. After the beginning of the swimming season, local authorities and employees of the Russian Emergencies Ministry regularly publish warnings in the media that swimming in certain places after severe storms is prohibited, but vacationers tend to ignore such messages. People don't want to waste their long-awaited vacation days no matter what.

This topic, for example, was devoted to the plot regional TV channel"360", which is called "Tourists in Anapa ignored the warning about the bottom current. And it is deadly ”(release date - July 1, 2019).

The authors of the TV report Anastasia Kukova and Yekaterina Andronova talked with the head of the Krasnodar Regional Hydrometeorological Center, Andrey Bondar. The specialist said that the tourist season of 2019 is just beginning, and several cases have already been recorded on the beaches of Anapa when vacationers were carried out to sea. This is because people do not pay attention to storm warnings and behave inadvertently.

“The wind is strong enough now. On our coast, the current is mainly of the western direction, and it catches up the surface water to the coast. Therefore, the bottom countercurrent increases. If you dive, you can be carried far enough from the shore, and it will be very difficult to swim out, ”A.N. Cooper.

How to escape from such a tide

Experienced swimmers and lifeguards say that people who are trapped in a reverse flow should not panic. The main thing is to soberly assess the current situation.

Maksim Selinsky, the author of the daily educational journal ShkolaZhizni.ru, wrote an article “The rip current is the main danger for swimming in the ocean or sea” (published on September 7, 2017). It says that it is panic that most often leads to the death of a swimmer, who desperately rushes to the shore, losing his last strength and completely exhausted. People should remember that an ordinary draft is only 5-10 meters wide, it is not able to carry a person far into the open sea: the rip current, as a rule, completely weakens less than 100 meters from the coast.

“Don't try to fight the tide. Its speed can be such that even an Olympic swimming champion cannot cope with it. Once in the opposite current, one should swim not directly towards the coast, but parallel to it, that is, away from the current. In this way, you can get out of the trap, after which you can swim towards the shore. Or, realizing that you are being carried away by the rip current, swim at an angle of 45 degrees to the shore and gradually get ashore, "advises Maksim Selinsky.

And of course, you should be careful not to ignore the warnings of the rescuers, carefully observe the coastal water area. If in any place water moves in reverse side from the coast, this can be seen by the change in color of the wave and the white foam (lambs) appearing on the surface.