The direction of movement of sea water on the Black Sea coast. Hydrographic map of the Black Sea

When measuring heights on land, the reading starts from sea level. This does not mean that the sea level is exactly the same in all areas of the oceans. In particular, the level of the Black Sea near Odessa is 30 cm higher than near Istanbul, for this reason water rushes from the Black Sea to the Mediterranean (through the Sea of ​​Marmara), and there is a constant current in the Bosphorus Strait that carries the Black Sea water. It is known that the atmosphere is cold air moves down towards warmer, lighter air. The water in the Bosphorus moves in exactly the same way - the heavy Mediterranean flows from below towards the Black Sea. It is interesting that the Mediterranean water is warmer, but, despite this, heavier: the density of water depends more not on temperature, but on salinity. 0.03 sq. km. It is a bit crowded here for two opposite currents. Foreign scientists took measurements in the Bosphorus in the 40-50s of our century and stated that there is no permanent lower current in the strait. Mediterranean water enters the Black Sea allegedly only occasionally, in small quantities. The materials used for such a "revolution in science" turned out to be clearly insufficient. The authors of the "discovery" did not pay attention to such an obvious circumstance: the flow of river waters into the Black Sea far exceeds the evaporation from its surface. So, if the sea did not constantly salt the mediterranean sea ​​water , it would become fresh. This is typical for the Black Sea, since in the Mediterranean, for example, evaporation exceeds river runoff, and the dynamics of the salt balance there is different. Accurate Facts are decisive in scientific disputes, so Soviet scientists, starting in 1958, conducted many years of research, now no longer in the strait, but in the Bosphorus region of the Black Sea. Expedition work was headed by hydrologists of the Institute of Biology of the Southern Seas, located in Sevastopol; our scientific institutions, as well as Bulgarian and Romanian scientists, took part in them. Expeditions in the Bosphorus region made it possible to establish that in all seasons of the year the Mediterranean water enters the Black Sea. After leaving the strait, this heavy water goes near the bottom, to the east, forming a stream 2 to 8 m thick, turns to the northwest after 5-6 miles, and in the region of the continental slope it breaks into separate jets, gradually descends to a great depth and mixes with the Black Sea water. Studies have shown that in the Bosphorus both currents have a speed of about 80 cm / s. The Black Sea receives about 170 cubic meters per year. km of Mediterranean water, and about 360 cubic meters flow out. km of Black Sea water. To fully determine the water balance of the Black Sea, it is also necessary to take into account the exchange with the Sea of ​​Azov, the flow of river waters. precipitation and evaporation. The study of the water balance of the sea is reminiscent of solving a school problem about a pool with pipes. Only the problem of the sea is incomparably more difficult. Nevertheless, it is already possible to fairly accurately predict the changes that will occur to the sea during certain major transformations of nature. The regulation of rivers by dams, the creation of reservoirs and diversion channels leads to a decrease in river flow, since part of the water no longer reaches the sea. The scale of these transformations is enormous. If in the Black Sea salinity does not change very noticeably yet, then in the shallow Azov Sea salinization already leads to a noticeable decrease in fish stocks. The more salty Black Sea water enters the Sea of ​​Azov through the Kerch Strait, in which, as in the Bosporus, there are opposite currents. Previously, the Sea of ​​​​Azov took about 33 cubic meters. km of Black Sea water per year and gave 51 cubic meters. km of its own, less salty water. After the regulation of the Don and Kuban, the ratio changed in favor of the Black Sea water, and the Sea of ​​Azov began to become saline. Salinity exceeded 12‰. This led to a decrease in the food supply for gobies and other fish. The most valuable freshwater fish for fishing began to stay closer to the mouths of the rivers, and the immobile mollusks are destroyed by the saltier water going down. To improve water balance Sea of ​​Azov, it was decided to regulate the exchange of water in the Kerch Strait. This will allow controlling the sea level, its salinity, and will create conditions for increasing the fish stocks of Azov. One of the difficulties is that with reduced river flow, there is nothing to compensate for evaporation. There is still no need to artificially change the water exchange in the Bosporus to regulate the salinity of the Black Sea. But, perhaps, such a problem will someday have to be solved by countries interested in its fate. Near the mouths of the rivers, the Black Sea water is less salty than in the central part of the sea. But in deep-sea regions, far from the coast, does the Black Sea water have the same composition throughout the entire thickness of the sea? Is the water stagnant here or does it mix? It has long been established that currents exist in the upper layers of the seas. They are caused by winds, level differences and differences in water density. Scheme of currents in the Black Sea Some currents are constant and resemble rivers, others often change speed and direction (for example, depending on the nature of the winds). In the Black Sea, one of the causes of currents is the difference in level between its northern and southern parts, which we have already discussed. Water from the northwestern region of the sea "flows" to the south. But the rotation of the earth causes this current to deviate to the west, and it runs counterclockwise along the coast. The width of the current is about 60 km, and the speed of water movement is 0.5 m/s. Part of the water goes into the Bosporus, and the rest of the mass moves on, turning north at the eastern coast of the sea. Where the current bends around the wide ledge of the Anatolian coast, part of the stream forms a branch, heading immediately north; there is a western annular current. The eastern half of the sea also has its own annular counterclockwise current. Currents in the Black Sea are often disturbed by strong winds that move significant masses of water and can noticeably change the water level, sometimes by half a meter. When the wind blows from the shore, it drives the surface warm water into the open sea. The water level is dropping. During such an offshore wind, stones covered with algae are exposed near the shore. Instead of the departed warm water at the surface, it turns out to be cold water that has risen from the depths. A surge wind directed from the sea to the shore brings warm surface water and raises the water level near the coast. The ebbs and flows in the Black Sea are so small that the movement of water under the influence of the wind almost completely obscures them. (Tides arise in the World Ocean under the influence of lunar attraction, but in the inland seas the tidal wave does not reach great heights.)

The main current seen in the Black Sea is called the "Main Black Sea Current". It spreads along all coasts along the perimeter of the sea, directed counterclock-wise and folds into two vortex flows, called rings. These rings, reminiscent of giant glasses and the name of the hydrologist who first noticed and described them, gave the name to this phenomenon - Knipovich glasses.

The basis of the direction of the movement of the Black Sea current is the acceleration received by sea water due to the rotation of the planet. Physicists call this effect the Coriolis force. In addition to cosmic forces, on the movement surface water on the map of the Black Sea, the strength of the wind also influences. This explains the variability of the main Black Sea current: sometimes it is barely noticeable against the background of other, smaller currents, and sometimes its speed reaches one meter per second.

In coastal areas Black Sea anticyclonic gyres are observed - eddy currents directed opposite to the main current. They are most noticeable off the coast of the Caucasus and Anatolia. In these areas of the Black Sea, the direction of alongshore currents is usually determined by the direction of the prevailing wind and can change several times a day.

Vacationers on the Black Sea should be aware of the existence of such a type of local Black Sea currents as " traction". Most often, this current is formed during a storm near sandy, gently sloping shores. The water running ashore does not return evenly, but in jets along the channels spontaneously formed in the sandy bottom. It is dangerous to get into the jet of a drag: even an experienced swimmer, despite all his efforts, can be carried away into the open sea far from the coast. To get out of the drag, you need to swim to the shore not directly perpendicular, but at an angle to reduce the counter resistance of the receding water.

A variety of traction "in action" can be seen in the Black Sea ports. From time to time, ships moored to the pier begin movement along the coast as if controlled by a huge natural force. Sometimes this movement is so powerful that the metal mooring lines cannot withstand the pressure, and the ships have no other choice but to stop loading operations and lay down on the roadstead away from the coast.

The nature of the occurrence of a "port" draft differs from the draft that occurs during a storm. It is caused by special, imperceptible to the naked eye waves approaching the port gates. They are called long-period - the period of oscillation created by them is much longer than the periods of oscillation of ordinary waves.

Scientists from our country and abroad are studying the nature of this phenomenon. The result of their work is scientific and practical recommendations on the correct mooring of ships during the "drafts" and advice on designing safe ports that can extinguish the "evil" energy of long-period waves.

Many people who swim well or keep well on the water do not understand how you can drown near the shore when you can swim ?! Especially when you don’t know how, and therefore you don’t go deeper than waist-deep. Hearing news reports during the holiday season about tourists who “died near the shore”, they think that the victims either did not know how to swim or were intoxicated. But they are wrong. What then is the reason?

We are talking about a very dangerous, but little-known phenomenon - rip currents, which are often also called "pulls" and "rips" (English - rip current). There are rip currents in all corners of the planet, in the Gulf of Mexico, the Black Sea, and the island of Bali. Not only ordinary people can cope with these insidious rips, but also first-class swimmers who do not know how to behave in this situation. sea, etc.). In these places, at low tide, sand bars prevent the return of a mass of water into the sea. The water pressure on the narrow strait connecting the sea with the estuary increases many times over. As a result, a fast stream is formed, along which water moves at a speed of 2.5-3.0 m / s.

You can read about the physics of the occurrence of "rips" on your own in your favorite Wikipedia. Technically, it is enough for incompetent comrades to know that corridors with a reverse (towards the sea) flow constantly appear in one place or another right next to the shore. There are "rips" that are stable, and they are not so dangerous, because, as a rule, all the locals know about them and suggest where you do not need to go swimming. But there are so-called flash rip currents that come and go; they are the ones that pose a mortal danger. In most cases, the "rip" corridor is narrow, 2-3 meters, and it is easy to jump out of it to the right or left. Also, in most cases, the speed of the current in the "rip" is 4-5 km / h, which is also not dangerous. However, several times a day on the same beach, "rips" up to 50 meters wide and up to 200-400 meters long can occur! If a speed of 15 km / h is added to it, then, having got into such a "rip", if you do not know how to deal with it, you can read a prayer. What happens when a person gets into a "rip"? He is about to be dragged into the open ocean. If the "rip" is wide and the speed is even minimal (5 km / h), it is useless to resist, that is, to swim against the current - it will still drag you to the depth. It is sad just the fact that people who do not know about the "rips" begin to desperately resist and frantically swim exactly towards the coast, that is, against the current of the "rip". They, of course, fail, and after 20-30 seconds a MONSTER PANIC sets in! Can you imagine if a person cannot swim?! Here he stands, say, waist-deep in water and thinks: "Kaif! I won't go deeper, it's safe here!" What is there! It will fall into the "rip", the ocean will drag it away and will not ask for the last name, especially if it is a weak woman or old man. It will drag you to where there will be no bottom... But you don't know how to swim... It's better not to think.

How to be? How to deal with "rips"? If you can’t swim at all, there is only one recommendation: do not go into the water alone! Never! Only with someone experienced. Of course, you need to swim where there are lifeguards and red flags. Those who know how to swim should remember that the depth to the chest is already sufficient for a serious "rip" (10 km / h or more), which can drag into the open ocean. What to do if you are still blown away? First and foremost, DON'T PANIC! In no case, because, knowing about the rules of behavior in the "rip" and not panicking, you will get out in 100 cases out of 100. The second main thing is not to resist the reverse current and in no case swim to the shore! It sounds, of course, intimidating, but this is the only correct logic: resisting, you will not achieve anything, you will still continue to drag, but in a minute or two you will be exhausted, exhausted, tired and guaranteed to lose your composure. Hundreds and hundreds of excellent swimmers, athletes, athletes, weightlifters and bodybuilders unknowingly drowned in "rips". In this scenario, the case will not be for you. So, don't panic and don't swim to shore! What are you doing? First: try to get out of the "rip" to the side. That is, you are not swimming towards the shore, but parallel to it. Right or left, it doesn't matter. If the "rip" is narrow, 2-4 meters, then you will quickly get out of it. If it is wide - up to 50 meters, then, of course, it will not work. As soon as you realize that you can’t get out, immediately stop trying and ... relax! Lie on your back, but don't panic. Why? Because in a minute or two the oncoming current will end and leave you alone. After that, you will turn around and swim ... but not immediately to the shore, but first 50-100 meters to the side to bypass the "rip", otherwise you will stick back into it. Oh, and while you're relaxing downstream, don't forget to raise your hand high, then at least a lifeguard will help you on your way back. Another important detail to keep in mind: "rip" will not drag you to the bottom! It's not a whirlpool or a funnel. All the "rips" in the world are dragged from the shore along the surface, but not to the depth.

Finally, the last thing: all "rips" have clear identification marks (signs). If there are no lifeguards with red flags on the beach, you can independently determine the place of the oncoming current by one of the following signs (in any combination). Visible channel of seething water, perpendicular to the shore. A coastal zone with a changed color of the water (say, everything around is blue or green, and some area is white). A section of foam, some kind of marine vegetation, bubbles, which is steadily moving from the coast to the open sea. Gap in overall structure tidal waves (a continuous strip of waves, and in the middle a 5-10-meter gap). If you see any of the above, consider yourself lucky and just don't go swimming in this place. But what if you do not see any of the four signs? So you're out of luck, because 80 percent of dangerous flash rips don't show up visually. That is, professional rescuers will still be able to determine these places, but ordinary tourists are unlikely. Until they are pulled into one of these invisible "rips".

Map of the currents of the Black Sea cold and warm currents

What is a geographic map

A geographic map is an image of the Earth's surface with a coordinate grid and symbols, whose proportions directly depend on the scale. A geography map is a landmark by which you can identify the location of that, the yoke of an array, an object or a person’s place of residence. These are indispensable assistants for geologists, tourists, pilots and the military, whose professions are directly related to travel, trips over long distances.

Types of cards

Conditionally split geographic Maps available in 4 types:

• by coverage of the territory and these are maps of continents, countries;
• by appointment and these are tourism, educational, road, navigation, scientific and reference, technical, tourist maps;
• by content - thematic, general geographical, general political maps;
• by scale - small-scale, medium-scale and large-scale maps.

Each of the maps is devoted to a certain topic, the thematic one reflects islands, seas, vegetation, settlements, weather, soils, taking into account the coverage of the territory. The map can only represent the applied countries, continents or states separately on a certain scale. Taking into account how reduced this or that territory, the scale of the map is 1x1000.1500, which means a decrease in the distance by 20,000 times. Of course, it is easy to guess that the larger the scale, the more detailed the map is drawn. And yet, individual parts of the earth's surface on the map are distorted, in contrast to the globe, which is able to convey the appearance of the surface without changes. The earth is spherical and distortions occur, such as: area, angles, length of objects.

The currents in the sea can be figuratively compared to rivers without banks. In the science of the sea, it is customary to designate the direction of currents according to the principle “where to”. Unlike currents, wind and wave directions are determined by the “where from” principle. For example, a wind blowing from south to north will be called a southerly wind, and the current created by this wind will be called a northerly one.

Map of the currents of the Black Sea

The currents of the Black Sea are weak, their speed rarely exceeds 0.5 meters per second, their main causes are the flow of rivers and the impact of winds. Under the influence of the flow of rivers, the water should move towards the center of the sea, but under the influence of the force of the Earth's rotation, it deviates to the right (in the northern hemisphere) by 90 degrees and goes along the coast in a counterclockwise direction. The main jet of currents has a width of 40-60 kilometers and passes at a distance of 3-7 kilometers from the coast.

In the bays, separate gyres are formed, directed clockwise, their speed reaches 0.5 meters per second.
the central part of the sea is a zone of calm, where the currents are weaker than near the coast, and are not constant in direction. Some researchers distinguish two separate rings in the general flow. The origin of the two rings of currents is associated with the features of the outlines of the Black Sea, which contribute to the deviation to the left of parts of the total flow off the coast of Crimea and Turkey.

An interesting system of currents is observed in the Bosphorus, it has great importance for the Black Sea.

These currents were first studied at the end of the last century by Admiral Makarov. S. O. Makarov was not only an outstanding naval commander, shipbuilder, military theorist, he was also a remarkable scientist who understood how important it was to know the environment in which the navy had to operate.

From conversations with local residents, S. O. Makarov established that there are two currents in the Bosphorus: surface and deep. He verified this fact by successively lowering the load into the water at different depths. The cargo was secured by a cable with a buoy floating on the surface. When the cargo was in the surface layers, the buoy moved to the Sea of ​​Marmara, when the cargo was at the bottom, the buoy was carried to the Black Sea. Thus, it was found that the surface current, carrying desalinated water, goes to the Sea of ​​Marmara, and the deep one, carrying denser salt water, goes to the Black Sea. S. O. Makarov found that the speed of the upper current is 1.5 meters per second, the lower one is 0.75 meters per second; the depth of the current interface is 20 meters. The lower current does not go strictly under the upper one, both of them are reflected from the capes, sometimes the jets of the currents bifurcate.

To explain the causes of these currents, Makarov did the following experiment. Water was poured into a glass box, divided into two parts: salty in one part, desalinated in the other. Two holes were made in the partition one above the other. Salt water began to move through the lower hole, desalinated water - through the upper one. S. O. Makarov was the first to explain the origin of these two layers. The upper course is wastewater, it is formed under the influence of excess water brought by rivers to the Black Sea. The lower one, the so-called density one, is formed as a result of the fact that the denser waters of the Marmara Sea exert more pressure on the underlying layers than the lighter waters of the Black Sea. This causes water to move from an area of ​​higher pressure to an area of ​​lower pressure.