Warm ocean currents. What is the cold current of the Atlantic Ocean? Description of the cold currents of the Atlantic. Currents of the oceans

Marine (oceanic) or simply currents are the translational movements of water masses in the oceans and seas over distances measured in hundreds and thousands of kilometers, due to various forces (gravitational, friction, tide-forming).

There are several classifications of sea currents in the oceanological scientific literature. According to one of them, currents can be classified according to the following criteria (Fig. 1.1.):

1. according to the forces that cause them, that is, according to their origin (genetic classification);

2. stability (variability);

3. by location depth;

4. by the nature of the movement;

5. according to physical and chemical properties.

The main one is the genetic classification, in which three groups of currents are distinguished.

1. In the first group of genetic classification - gradient currents due to horizontal hydrostatic pressure gradients. There are the following gradient currents:

Density, due to the horizontal density gradient (uneven distribution of temperature and salinity of water, and, consequently, density horizontally);

compensation, due to the slope of the sea level, which arose under the influence of the wind;

Barogradient, due to uneven atmospheric pressure above sea level;

· runoff, formed as a result of an excess of water in any area of the sea, as a result of the inflow of river water, heavy precipitation or ice melting;

· seiche, arising from seiche vibrations of the sea (fluctuations in the water of the entire basin as a whole).

Currents that exist when the horizontal gradient of hydrostatic pressure and the Coriolis force are in equilibrium are called geostrophic.

The second group of gradient classification includes currents caused by the action of the wind. They are divided into:

Drift winds are created by prolonged, or prevailing, winds. These include the trade winds of all oceans and the circumpolar current in the southern hemisphere (the current of the West Winds);

wind, caused not only by the action of the direction of the wind, but also by the slope of the level surface and the redistribution of water density caused by the wind.

The third group of classification gradients includes tidal currents caused by tidal phenomena. These currents are most noticeable near the coast, in shallow waters, in the mouths of rivers. They are the strongest.

As a rule, total currents are observed in the oceans and seas, due to the combined action of several forces. Currents that exist after the cessation of the action of the forces that caused the movement of water are called inertial. Under the action of friction forces, inertial flows gradually fade.

2. According to the nature of stability, variability, currents are distinguished as periodic and non-periodic (stable and unstable). Currents, changes of which occur with a certain period, are called periodic. These include tidal currents that vary mainly with a period of approximately half a day (semidiurnal tidal currents) or days (diurnal tidal currents).

Rice. 1.1. Classification of currents of the oceans

Currents whose changes do not have a clear periodic character are usually called non-periodic. They owe their origin to random, unexpected causes (for example, the passage of a cyclone over the sea causes non-periodic wind and barometric currents).

There are no permanent currents in the strict sense of the word in the oceans and seas. Relatively little changing currents in direction and speed for the season are monsoon, for the year - trade winds. A flow that does not change with time is called steady flow, and a flow that changes with time is called unsteady flow.

3. According to the depth of location, surface, deep and near-bottom currents are distinguished. Surface currents are observed in the so-called navigation layer (from the surface to 10 - 15 m), near-bottom currents are near the bottom, and deep ones - between the surface and near-bottom currents. The speed of movement of surface currents is highest in the uppermost layer. Deeper it goes down. Deep waters move much more slowly, and the speed of movement of bottom waters is 3–5 cm/s. The speed of the currents is not the same in different regions of the ocean.

4. According to the nature of the movement, meandering, rectilinear, cyclonic and anticyclonic currents are distinguished. Meandering currents are called currents that do not move in a straight line, but form horizontal undulating bends - meanders. Due to the instability of the flow, meanders can separate from the flow and form independently existing eddies. Rectilinear currents are characterized by the movement of water in relatively straight lines. Circular currents form closed circles. If the movement in them is directed counterclockwise, then these are cyclonic currents, and if clockwise, then they are anticyclonic (for the northern hemisphere).

5. According to the nature of physical and chemical properties, warm, cold, neutral, salty and fresh water currents are distinguished (the division of currents according to these properties is to a certain extent conditional). To assess the specified characteristic of the current, its temperature (salinity) is compared with the temperature (salinity) of the surrounding waters. Thus, a warm (cold) flow is a water temperature in which the temperature of the surrounding waters is higher (lower). For example, the deep current of Atlantic origin in the Arctic Ocean has a temperature of about 2 °C, but belongs to warm currents, and the Peruvian Current off the western coast of South America, which has a water temperature of about 22 °C, belongs to cold currents.

The main characteristics of the sea current: speed and direction. The latter is determined in the reverse way compared to the direction of the wind, i.e., in the case of a current, it indicates where the water flows, while in the case of a wind, it indicates where it blows from. Vertical movements of water masses are usually not taken into account when studying sea currents, since they are not large.

In the oceans there is a single, interconnected system of main stable currents (Fig. 1.2.), which determines the transfer and interaction of waters. This system is called oceanic circulation.

The main force that drives the surface waters of the ocean is the wind. Therefore, surface currents should be considered with prevailing winds.

Within the southern periphery of the oceanic anticyclones of the northern hemisphere and the northern periphery of the southern hemisphere anticyclones (the centers of anticyclones are located at 30 - 35 ° north and south latitude), a system of trade winds operates, under the influence of which stable powerful surface currents are formed, directed to the west (North and South trade winds). currents). Encountering the eastern shores of the continents on their way, these currents create a rise in level and turn to high latitudes (Guiana, Brazil, etc.). In temperate latitudes (about 40°) westerly winds predominate, which intensifies currents going to the east (North Atlantic, North Pacific, etc.). In the eastern parts of the oceans between 40 and 20 ° north and south latitude, the currents are directed towards the equator (Canary, California, Benguela, Peru, etc.).

Thus, stable water circulation systems are formed in the oceans north and south of the equator, which are giant anticyclonic gyres. Thus, in the Atlantic Ocean, the northern anticyclonic gyre extends from south to north from 5 to 50° north latitude and from east to west from 8 to 80° west longitude. The center of this cycle is shifted relative to the center of the Azores anticyclone to the west, which is explained by the increase in the Coriolis force with latitude. This leads to the intensification of currents in the western parts of the oceans, creating conditions for the formation of such powerful currents as the Gulf Stream in the Atlantic and Kuroshio in the Pacific Ocean.

A peculiar division between the North and South trade winds is the Intertrade countercurrent, which carries its waters to the east.

In the northern part of the Indian Ocean, the Hindustan peninsula, which protrudes deeply to the south, and the vast Asian continent create favorable conditions for the development of monsoon circulation. In November - March, the northeast monsoon is observed here, and in May - September - southwest. In this regard, currents north of 8° south latitude have a seasonal course, following the seasonal course of atmospheric circulation. In winter, the western monsoon current is observed at the equator and north of it, i.e., during this season, the direction of surface currents in the northern part of the Indian Ocean corresponds to the direction of currents in other oceans. At the same time, in the zone separating the monsoon and trade winds (3 - 8 ° south latitude), a surface equatorial countercurrent develops. In summer, the western monsoon current is replaced by an eastern one, and the equatorial countercurrent is replaced by weak and unstable currents.

Rice. 1.2.

In temperate latitudes (45 - 65 °) in the northern part of the Atlantic and Pacific oceans, counterclockwise circulation takes place. However, due to the instability of the atmospheric circulation in these latitudes, the currents are also characterized by low stability. In the band 40 - 50 ° south latitude is the Atlantic circumpolar current directed to the east, also called the current of the West Winds.

Off the coast of Antarctica, the currents are predominantly westward and form a narrow strip of coastal circulation along the shores of the mainland.

The North Atlantic Current penetrates into the Arctic Ocean basin in the form of branches of the Norwegian, North Cape and Svalbard currents. In the Arctic Ocean, surface currents are directed from the shores of Asia across the pole to the eastern shores of Greenland. This nature of the currents is caused by the predominance of easterly winds and the compensation of the inflow in the deep layers of the Atlantic waters.

In the ocean, zones of divergence and convergence are distinguished, characterized by the divergence and convergence of surface jets of currents. In the first case, the water rises; in the second, it sinks. Of these zones, convergence zones are more clearly distinguished (for example, the Antarctic convergence at 50 - 60 ° south latitude).

Let us consider the features of the circulation of the waters of individual oceans and the characteristics of the main currents of the World Ocean (table).

In the northern and southern parts of the Atlantic Ocean, in the surface layer, there are closed circulations of currents with centers near 30 ° north and south latitude. (The circulation in the northern part of the ocean will be discussed in the next chapter).

The main currents of the oceans

Name	Temperature gradation	Sustainability	Average speed, cm/s

northern trade wind	Neutral	sustainable
Mindanao	Neutral	sustainable
		Very stable
North Pacific	Neutral	sustainable
		sustainable
Aleutian	Neutral	unstable
Kuril-Kamchatskoye	Cold	sustainable
california	Cold	unstable
Intertrade countercurrent	Neutral	sustainable
southern trade wind	Neutral	sustainable
East Australian		sustainable
South Pacific	Neutral	unstable
Peruvian	Cold	Weakly stable
El Niño		Weakly stable
Antarctic circumpolar	Neutral	sustainable
Indian
southern trade wind	Neutral	sustainable
Cape Agulhas		Very stable
Western Australian	Cold	unstable
Antarctic circumpolar	Neutral	sustainable
Northern	arctic
Norwegian		sustainable
West Spitsbergen		sustainable
East Greenland	Cold	sustainable
West Greenland		sustainable
Atlantic
northern trade wind	Neutral	sustainable
Gulfstream		Very stable
North Atlantic		Very stable
Canarian	Cold	sustainable
Irminger		sustainable
Labrador	Cold	sustainable
Intertrade countercurrent	Neutral	sustainable
southern trade wind	Neutral	sustainable
brazilian		sustainable
Benguela	Cold	sustainable
Falkland	Cold	sustainable
Antarctic circumpolar	Neutral	sustainable

In the southern part of the ocean, the warm Brazilian current carries water (at a speed of up to 0.5 m/s) far to the south, and the Benguela current, branched off from the powerful current of the West Winds, closes the main circulation in the southern part of the Atlantic Ocean and brings cold water to the coast of Africa.

The cold waters of the Falkland Current penetrate the Atlantic, rounding Cape Horn and pouring between the shore and the Brazil Current.

A feature in the circulation of the waters of the surface layer of the Atlantic Ocean is the presence of the Lomonosov subsurface equatorial countercurrent, which moves along the equator from west to east under a relatively thin layer of the South trade wind current (depth from 50 to 300 m) at a speed of up to 1 - 1.5 m/s. The current is stable in direction and exists in all seasons of the year.

Geographical position, climatic features, water circulation systems and good water exchange with Antarctic waters determine the hydrological conditions of the Indian Ocean.

In the northern part of the Indian Ocean, unlike other oceans, the monsoonal circulation of the atmosphere causes a seasonal change in surface currents north of 8 ° south latitude. In winter, the Western Monsoon Current is observed at a speed of 1 - 1.5 m/s. In this season, the Equatorial countercurrent develops (in the zone of separation of the Monsoon and South trade winds) and disappears.

Compared to other oceans in the Indian Ocean, the zone of prevailing southeast winds, under the influence of which the South Trade Wind Current arises, is shifted to the south, so this current moves from east to west (speed 0.5 - 0.8 m / s) between 10 and 20° south latitude. Off the coast of Madagascar, the South Tradewind current splits. One of its branches runs north along the coast of Africa to the equator, where it turns east and in winter gives rise to the Equatorial Countercurrent. In summer, the northern branch of the South Trade Wind Current, moving along the coast of Africa, gives rise to the Somali Current. Another branch of the South Trade Wind Current off the coast of Africa turns south and, under the name of the Mozambique Current, moves along the coast of Africa to the southwest, where its branch gives rise to the Cape Agulhas Current. Most of the Mozambique Current turns east and joins the West Wind Current, from which the West Australian Current branches off off the coast of Australia, completing the circulation of the southern Indian Ocean.

The insignificant inflow of Arctic and Antarctic cold waters, the geographic position and the system of currents determine the features of the hydrological regime of the Pacific Ocean.

A characteristic feature of the general scheme of the surface currents of the Pacific Ocean is the presence of large water cycles in its northern and southern parts.

In the trade winds, under the influence of constant winds, the South and North trade winds arise, going from east to west. Between them, from west to east, the Equatorial (Intertrade) countercurrents move with speeds of 0.5 - 1 m / s.

The northern trade wind current near the Philippine Islands is divided into several branches. One of them turns south, then east and gives rise to the Equatorial (Intertrade) countercurrent. The main branch follows north along the island of Taiwan (Taiwan current), then turns to the northeast and under the name Kuroshio passes along the eastern coast of Japan (speed up to 1 - 1.5 m / s) to Cape Nojima (Honshu Island). Further, it deviates to the east and crosses the ocean as the North Pacific Current. A characteristic feature of the Kuroshio Current, like the Gulf Stream, is meandering and displacement of its axis either to the south or to the north. Off the coast of North America, the North Pacific Current bifurcates into the California Current, directed to the south and closing the main cyclonic circulation of the North Pacific Ocean, and the Alaska Current, going to the north.

The cold Kamchatka Current originates in the Bering Sea and flows along the shores of Kamchatka, the Kuril Islands (Kuril Current), and the coast of Japan, pushing the Kuroshio Current to the east.

The southern trade wind current moves to the west (velocity 0.5 - 0.8 m/s) with numerous branches. Off the coast of New Guinea, part of the flow turns north and then east and, together with the southern branch of the North Trade Wind Current, gives rise to the Equatorial (Intertrade) countercurrent. Most of the South Trade Wind Current is deflected, forming the East Australian Current, which then flows into the powerful West Wind Current, from which the cold Peruvian Current branches off off the coast of South America, completing the circulation in the South Pacific Ocean.

In the summer period of the southern hemisphere, towards the Peruvian current from the Equatorial countercurrent, the warm El Niño current moves south to 1 - 2 ° south latitude, penetrating in some years to 14 - 15 ° south latitude. Such an intrusion of the warm waters of El Niño into the southern regions of the coast of Peru leads to catastrophic consequences due to an increase in the temperature of water and air (heavy showers, death of fish, epidemics).

A characteristic feature in the distribution of currents in the surface layer of the ocean is the presence of the Equatorial subsurface countercurrent - the Cromwell Current. It crosses the ocean along the equator from west to east at a depth of 30 to 300 m at a speed of up to 1.5 m/s. The current covers a strip with a width from 2° north latitude to 2° south latitude.

The most characteristic feature of the Arctic Ocean is that its surface is covered with floating ice throughout the year. The low temperature and salinity of the waters favor the formation of ice. Coastal waters are free of ice only in summer, for two to four months. In the central part of the Arctic, mainly heavy multi-year ice (pack ice) with a thickness of more than 2 - 3 m, covered with numerous hummocks, is observed. In addition to multi-year ice, there are one-year and two-year ice. A rather wide (tens and hundreds of meters) strip of fast ice forms along the Arctic shores in winter. There are no ices only in the area of the warm Norwegian, North Cape and Svalbard currents.

Under the influence of winds and currents, the ice in the Arctic Ocean is in constant motion.

Well-defined areas of cyclonic and anticyclonic water circulation are observed on the surface of the Arctic Ocean.

Under the influence of the polar baric maximum in the Pacific part of the Arctic Basin and the hollow of the Icelandic minimum, a general Transarctic current arises. It carries out the general movement of waters from east to west throughout the polar area. The Transarctic Current originates from the Bering Strait and goes to the Fram Strait (between Greenland and Svalbard). Its continuation is the East Greenland current. Between Alaska and Canada there is an extensive anticyclonic water cycle. The cold Baffin Current is formed mainly due to the removal of Arctic waters through the straits of the Canadian Arctic Archipelago. Its continuation is the Labrador Current.

The average speed of water movement is about 15 - 20 cm / s.

A cyclonic, very intense cycle occurs in the Norwegian and Greenland Seas in the Atlantic part of the Arctic Ocean.

Name the warm and cold currents of the Atlantic Ocean.
Urgent Geography

There are 15 currents in the Atlantic Ocean: 10 warm currents, 5 cold ones. WARM The northern trade wind current is warm. (Sptt) The Gulf Stream is warm. (Gtt) Antilles current is warm (Att) North Atlantic current is warm. (Sutt) Caribbean current is warm. (Kartt) The inter-trade countercurrent is warm. (Mprt) South trade wind current is warm. (Juptt) Lomonosov current is warm (TLt) Guinean current is warm (Gwtt) Brazilian current is warm. (Brtt) COLD Canarian current is cold. (Kanth) Labrador current is cold (Labth) Bengal current is cold. (Benth) The Falkland current is cold (Folth) The current of the westerly winds is cold..
WARM
northern trade wind
Gulfstream
Antilles Current
north atlantic
caribbean current
Intertrade
south trade wind
Lomonosov Current
Guinean
brazilian
COLD
Canarian
Labrador
Bengal
Falkland
The course of the westerly winds

sea currents are masses of water moving under the influence of prevailing winds or due to differences in temperature and salt content in the water. Sometimes they form funnels, rotating clockwise in the northern hemisphere, and on the opposite side - in the south.

There are three main types of flows: superficial, medium and deep.

Surface currents, extending between the surface of the water and a depth of 700 meters, develop rapidly under the influence of prevailing winds such as trade winds (in the Northern Hemisphere, trade winds from the northeast to the southwest in the southern hemisphere - from the southeast to the northwest).

Average runoff depth (from 1000 to 2500 meters) and deep (to depths of more than 2500 meters), with differences in temperature and salinity caused by the mixing of cold water from the Arctic and Antarctic heating pads.

Gulfstream

Originating in the tropics, this warm North Atlantic current must, along the coast of West Africa, then the coast of Brazil, pass between the Antilles and Central America and wing in Florida before reaching Newfoundland (Canada).

One of the Gulf Stream's missiles, the North Atlantic Stream, is partly the basis of the warm climate of Western Europe.

Kurosivo

This flow in the North Pacific Ocean is formed at the latitude of the Philippines and then along the east coast of Japan and is created as the northern Pacific subcontinent that rises to the west coast of the United States.

Humboldt flow

It is a cool current in the Pacific Ocean that follows the coasts of Peru and Chile and contributes to the complex atmosphere of these countries.

brazilian stream

This tropical stream in the southeast warms the waters along the coasts of Argentina and Brazil.

El Niño

It's a warm current in the Pacific, blamed for the worst: floods in Asia and the United States, severe droughts in Australia, and an increase in typhoons in the Pacific; However, expert opinions differ in terms of its actual impact on climate change.

somali stream

The fastest current in the Indian Ocean moves along the east coast of Africa at over 12 km/h.

Antarctic circular flow

The strongest current on the planet moves east between the southern coasts of Africa, South America and Australia and the Antarctic Circle.

Ebb and flow

Birds are sea surface changes caused by the attraction of the moon and sun into water particles.

Normally the water level rises twice a day (tide) and falls twice a day. The most famous example in Europe is the tides on the Atlantic coast and in the English Channel. In the Gulf of San Michele, the difference in water level can be up to 15 meters! Sometimes the sea rises at over 30 km/h, suddenly caught by unwanted swimmers…

The currents influence the monsoon.

GULF STREAM, (eng. Gulf Stream, literally - the course of the bay), a warm current in the North Atlantic. In a broad sense, a powerful system of warm currents, stretching for 10,000 km from the shores of the Florida peninsula to the islands of Svalbard and Novaya Zemlya, is called hydrogeology. G. proper begins in the southern part of the Strait of Florida as a waste current of the Gulf of Mexico at its confluence with the waters of the Antilles Current and continues to the Great Newfoundland Bank.

The reason for its origin is a large surge of trade winds of water through the Yucatan Strait into the Gulf of Mexico and the resulting significant level difference between the Gulf of Mexico and the adjacent part of the Atlantic Ocean. When entering the ocean, the current capacity is 25 million m³ / s. (2160 km³ per day), which is 20 times the flow of all rivers in the world. In the ocean, it connects with the Antilles current, and the power of G.

increases by 38° N. sh. Reaches 82 million m³/sec. One of the features of hydrogeography is that, in violation of the general pattern of movement in the Northern Hemisphere, this current, upon entering the ocean, deviates not to the right under the influence of the force of the Earth's rotation, but to the left. In the ocean, G. moves in a northerly direction, along the edge of the continental shelf of North America, and at Cape Hatteras it deviates to the northeast, to the Newfoundland Bank.

After passing it, at about 40° W. d., G. proper passes into the North Atlantic Current, which, under the influence of western and southwestern winds, crosses the ocean from east to west, gradually changing direction off the coast of Europe to the northeast. When approaching the port of Thomson, a branch separates from the North Atlantic Current - the warm Irminger Current, which partially enters the Greenland Sea, skirting Iceland from the west, but moves westward in its main mass, skirts Greenland from the south and follows along its western coast called the West Greenland Current in the Baffin Sea.

The main flow of the North Atlantic Current continues into the Norwegian Sea and follows north along the western coast of the Scandinavian Peninsula under the name of the Norwegian Current. At the northern tip of the Scandinavian Peninsula, a branch separates from it - the North Cape Current, which follows east along the southern part of the Barents Sea. The main stream of the Norwegian Current continues north and, under the name of the Svalbard Current, runs along the western coast of Svalbard. North of Svalbard, this current sinks to depths and can be traced in the Arctic Ocean under cold and fresh surface waters as a warm and salty intermediate current.

The width of the sea in different parts of the sea is 75–200 km, the flow thickness is 700–800 m, the speed is 80–300 cm/sec, and the water temperature on the surface is from 10 to 28°C. The system of warm water currents has a great influence on the hydrological and biological characteristics of both the seas and the Arctic Ocean itself, and on the climate of the countries of Europe adjacent to the Atlantic Ocean.

Masses of warm water heat the air passing over them, which is carried by western winds to Europe (southern trees grow in the west of Norway at the latitude of Magadan). One of the branches of the Gulf Stream - the North Cape Current - reaches the Kola Peninsula, allowing the Kola Bay and the seaports on Murman, in particular, not to freeze (the air temperature in Murmansk deviates from the average values at this latitude up to 11ºС).
In Russia, about the passage of G.

along the Murmansk coast, for the first time after studies of the temperature regime of the Barents Sea, F. F. Yarzhinsky announced at a meeting of the Russian Geographical Society in 1870 (previously there was a hypothesis by the German geographer A. Peterman). Subsequent observations by Academician A.F. Middendorf confirmed his data, although the capital was of the opinion that "there is no Gulfstrom and cannot be." N. M. Knipovich with employees of the Murmansk scientific and fishing expedition (1898–1908) discovered 4 branches of the North Cape warm current in the Barents Sea.

The southern, Murmansk, ran parallel to the coast of the Kola Peninsula, then splitting into two jets (to Novaya Zemlya and the Kaninsky shallow water).

The expedition established a connection between the migration of juveniles of bottom rocks and their accumulation on the shallows and banks with warm water jets, and it was proposed to expand the fishing area. New opportunities in the study of G.

opened in the middle of the 20th century. with the advent of more advanced scientific equipment.

Lit .: Middendorf A.F.

Gulfstrom to the east of the North Cape. - St. Petersburg, 1871; Shuleikin VV Physics of the sea. - M., 1953; Stommel G. Gulfstream.

M., 1963; Gershman, I.G., The Gulf Stream and Its Influence on the Climate, Meteorology and Hydrology. 1939. No. 7–8.

Scheme of heat transfer by the course of the Gulf Stream Group:

Climate; atmosphere

GLOSSARY > G
THEMATIC INDEX > SCIENCE > Natural (mathematics, physics, geography, geology, chemistry, biology, marine studies, etc.)
THEME INDEX > NATURE > Water resources (seas, rivers, lakes, bays)
THEMATIC INDEX > NATURE > Climate; atmosphere

Diversity climatic conditions on the surface of the Atlantic Ocean is determined by its large meridional extent and the circulation of air masses under the influence of four main atmospheric centers: Greenland and Antarctic max., Icelandic and Antarctic minima.

At the same time, two anticyclones constantly operate in the subtropics: Azores and South Atlantic. Οʜᴎ are separated by an equatorial region of low pressure. This distribution of baric regions determines the system of prevailing winds in the Atlantic. The greatest influence on the temperature regime of the Atlantic Ocean is exerted not only by its large meridional extent, but also by water exchange with the Arctic Ocean, the seas of the Antarctic and the Mediterranean Sea.

Tropical latitudes are characterized by tempera.

— 20 °C. To the north and south of the tropics are subtropical zones with more noticeable seasonal ones (from 10 ° C in winter to 20 ° C in summer). Tropical hurricanes are a frequent occurrence in the subtropical zone. In temperate latitudes, the average temperature of the warmest month is kept within 10-15 °C, and the coldest -10 °C.

Precipitation is about 1000 mm.

surface currents. North Equatorial Current (t)> Antilles (t)> Mexico. Gulf>Florida(t)>Gulf Stream>North Atlantic(t)>Canary(x)>Northern Equatorial Current(t) – northern circle.

South trade winds> Guiana temp.

(North) and the Brazilian Warm. (south)>tech. Western winds (x)> Benguela (x)> South trade winds - southern circle.

There are several levels in the Atlantic Ocean deep currents. A powerful countercurrent passes under the Gulf Stream, the main core of which lies at a depth of up to 3500 m, at a speed of 20 cm / s. The powerful deep Louisiana current is observed in the eastern part of the Atlantic Ocean, formed by the bottom runoff of saltier and warmer Mediterranean waters through the Strait of Gibraltar.

The highest tide values are confined to the Atlantic Ocean, which are noted in the fjord bays of Canada (in Ungava Bay - 12.4 m, in Frobisher Bay - 16.6 m) and Great Britain (up to 14.4 m in Bristol Bay).

The highest tide in the world is recorded in the Bay of Fundy, on the east coast of Canada, where the maximum tide reaches 15.6-18 m.

Salinity. The highest salinity of surface waters in the open ocean is observed in the subtropical zone (up to 37.25 ‰), and the maximum in the Mediterranean Sea is 39 ‰.

In the equatorial zone, where the maximum amount of precipitation is noted, salinity decreases to 34 ‰. A sharp desalination of water occurs in the estuarine areas (for example, at the mouth of La Plata 18-19 ‰).

Ice formation. Ice formation in the Atlantic Ocean occurs in the Greenland and Baffin Seas and Antarctic waters. The main source of icebergs in the South Atlantic is the Filchner Ice Shelf in the Weddell Sea. Floating ice in the northern hemisphere reaches 40°N in July.

Upwellin.

A particularly powerful upwelling zone stretches along the entire western coast of Africa, due to the wind<связан. с пассатной циркуляцией. Также это зоны у Зелёного мыса, у берегов Анголы и Конго.

These areas are most favorable for the development of orᴦ. peace.

The Atlantic Ocean, or the Atlantic, is the second largest (after the Pacific) and the most developed among other water areas. From the east it is limited by the coast of South and North America, from the west - by Africa and Europe, in the north - by Greenland, in the south it merges with the Southern Ocean.

Distinctive features of the Atlantic: a small number of islands, a complex bottom topography and a heavily indented coastline.

Ocean characteristics

Area: 91.66 million sq. km, with 16% of the territory falling on the seas and bays.

Volume: 329.66 million sq. km

Salinity: 35‰.

Depth: average - 3736 m, maximum - 8742 m (Puerto Rico Trench).

Temperature: in the very south and north - about 0 ° C, at the equator - 26-28 ° C.

Currents: conventionally, 2 circulations are distinguished - the Northern (currents move clockwise) and the Southern (counterclockwise). The gyres are separated by the Equatorial inter-trade countercurrent.

Main currents of the Atlantic Ocean

Warm:

Northern trade wind - begins off the western coast of Africa, crosses the ocean from east to west and meets the Gulf Stream near Cuba.

Gulfstream- the most powerful current in the world, which carries 140 million cubic meters of water per second (for comparison: all the rivers of the world carry only 1 million cubic meters of water per second). It originates near the coast of the Bahamas, where the Florida and Antilles currents meet. Together, they give rise to the Gulf Stream, which, through the strait between Cuba and the Florida Peninsula, enters the Atlantic Ocean with a powerful stream. The current then moves north along the US coast. Approximately off the coast of North Carolina, the Gulf Stream turns east and out into the open ocean. After about 1500 km, it meets the cold Labrador Current, which slightly changes the course of the Gulf Stream and carries it to the northeast. Closer to Europe, the current is divided into two branches: Azores and North Atlantic.

It has only recently become known that a reverse current flows 2 km below the Gulf Stream, heading from Greenland to the Sargasso Sea. This stream of icy water was called the Antigulf Stream.

north atlantic- a continuation of the Gulf Stream, which washes the western coast of Europe and brings the warmth of the southern latitudes, providing a mild and warm climate.

Antillean- begins east of the island of Puerto Rico, flows north and joins the Gulf Stream near the Bahamas. Speed — 1-1.9 km/h, water temperature 25-28°C.

Intertrade countercurrent - current around the globe at the equator. In the Atlantic, it separates the North Equatorial and South Equatorial currents.

South trade wind (or South Equatorial) - passes through the southern tropics. The average water temperature is 30°C. When the South Equatorial Current reaches the shores of South America, it divides into two branches: caribbean, or Guiana (flows north to the coast of Mexico) and brazilian- moves south along the coast of Brazil.

Guinean located in the Gulf of Guinea. It flows from west to east and then turns south. Together with the Angolan and South Equatorial forms a cyclic course of the Gulf of Guinea.

Cold:

Lomonosov countercurrent - discovered by a Soviet expedition in 1959. It originates off the coast of Brazil and moves north. A stream 200 km wide crosses the equator and flows into the Gulf of Guinea.

Canarian- flows from north to south, towards the equator along the coast of Africa. This wide stream (up to 1 thousand km) near Madeira and the Canary Islands meets the Azores and Portuguese currents. Approximately in the region of 15°N. joins with the Equatorial Countercurrent.

Labrador - begins in the strait between Canada and Greenland. It flows south to the Newfoundland bank, where it meets the Gulf Stream. The waters of the current carry cold from the Arctic Ocean, and along with the stream, huge icebergs are carried south. In particular, the iceberg that destroyed the famous Titanic was brought by the Labrador Current.

Benguela- is born near the Cape of Good Hope and moves along the coast of Africa to the north.

Falkland (or Malvinas) branches off from the West Wind Current and flows north along the east coast of South America to La Plata Bay. Temperature: 4-15°C.

The course of the westerly winds encircles the globe in the region of 40-50 °S. The stream moves from west to east. In the Atlantic it branches off South Atlantic flow.

Underwater world of the Atlantic Ocean

The underwater world of the Atlantic is poorer in diversity than in the Pacific Ocean. This is due to the fact that the Atlantic Ocean was more frozen during the ice age. But the Atlantic is richer in the number of individuals of each species.

The flora and fauna of the underwater world is clearly distributed across climatic zones.

The flora is represented mainly by algae and flowering plants (Zostera, Posidonia, Fucus). In the northern latitudes, kelp predominates, in temperate latitudes - red algae. Phytoplankton flourishes throughout the ocean at depths of up to 100 m.

The fauna is rich in species. Almost all species and classes of marine animals live in the Atlantic. Of the commercial fish, herring, sardine, and flounder are especially valued. There is an active catch of crustaceans and mollusks, whaling is limited.

The tropical belt of the Atlantic is striking in its abundance. There are many corals and many amazing species of animals: turtles, flying fish, several dozen species of sharks.

For the first time the name of the ocean is found in the writings of Herodotus (5th century BC), who calls it the sea of Atlantis. And in the 1st century AD. Roman scientist Pliny the Elder writes about the vast expanse of water, which he calls Oceanus Atlantikus. But the official name "Atlantic Ocean" was fixed only by the 17th century.

There are 4 stages in the history of Atlantic exploration:

1. From antiquity to the 15th century. The first documents that talk about the ocean date back to the 1st millennium BC. The ancient Phoenicians, Egyptians, Cretans and Greeks knew the coastal zones of the water area well. Preserved maps of those times with detailed measurements of depths, indications of currents.

2. Time of the Great geographical discoveries (XV-XVII centuries). The development of the Atlantic continues, the ocean becomes one of the main trade routes. In 1498, Vasco de Gama, rounding Africa, paved the way to India. 1493-1501 Three voyages of Columbus to America. The Bermuda anomaly has been identified, many currents have been discovered, detailed maps of depths, coastal zones, temperatures, and bottom topography have been compiled.

Expeditions of Franklin in 1770, I. Kruzenshtern and Yu. Lisyansky in 1804-06.

3. XIX-first half of the XX century - the beginning of scientific oceanographic research. Chemistry, physics, biology, geology of the ocean are being studied. A map of currents has been drawn up, and research is being carried out to lay a submarine cable between Europe and America.

4. 1950s - our days. A comprehensive study of all components of oceanography is being carried out. In priority: studying the climate of different zones, identifying global atmospheric problems, ecology, mining, ensuring the movement of ships, seafood.

In the center of the Belize Barrier Reef is a unique underwater cave - the Great Blue Hole. Its depth is 120 meters, and at the very bottom there is a whole gallery of smaller caves connected by tunnels.

The only sea in the world without shores, the Sargasso, is located in the Atlantic. Its borders are formed by ocean currents.

One of the most mysterious places on the planet is located here: the Bermuda Triangle. The Atlantic Ocean is also the birthplace of another myth (or reality?) - the mainland of Atlantis.

4. Ocean currents.

The constant and continuous movement of water masses is the eternal dynamic state of the ocean. If the rivers on Earth flow towards the sea along their inclined channels under the influence of the force of gravity, then the currents in the ocean are caused by various reasons. The main causes of sea currents are: wind (drift currents), unevenness or changes in atmospheric pressure (barogradient), attraction of water masses by the Sun and Moon (tidal), difference in water density (due to the difference in salinity and temperature), level difference created by inflow of river water from the continents (stock).

Not every movement of ocean water can be called a current. Sea currents in oceanography are the translational movement of water masses in the oceans and seas..

Two physical forces cause currents - friction and gravity. Excited by these forces currents called frictional And gravitational.

The current in the World Ocean is usually caused by several reasons at once. For example, the mighty Gulf Stream is formed by the confluence of density, wind and runoff currents.

The initial direction of any current soon changes under the influence of the Earth's rotation, frictional forces, the configuration of the coastline and the bottom.

According to the degree of stability, currents are distinguished sustainable(for example, the North and South trade winds), temporary(surface currents of the northern Indian Ocean caused by monsoons) and periodical(tidal).

According to the position in the thickness of the ocean waters, the currents can be surface, subsurface, intermediate, deep And bottom. In this case, the definition of "surface current" sometimes refers to a sufficiently powerful layer of water. For example, the thickness of the trade wind countercurrents in the equatorial latitudes of the oceans can be 300 m, and the thickness of the Somali current in the northwestern part of the Indian Ocean reaches 1000 meters. It is noted that deep currents are most often directed in the opposite direction compared to surface waters moving above them.

Currents are also divided into warm and cold. warm currents move water masses from low latitudes to higher latitudes, and cold- in the opposite direction. This division of currents is relative: it characterizes only the surface temperature of moving waters in comparison with the surrounding water masses. For example, in the warm North Cape Current (Barents Sea), the temperature of the surface layers is 2–5 °С in winter and 5–8 °С in summer, and in the cold Peruvian Current (Pacific Ocean) it is 15 to 20 °С all year round, in the cold Canary (Atlantic) - from 12 to 26 ° С.

The main data source is ARGO buoys. The fields are obtained using optimal analysis.

Some currents in the oceans are connected with other currents, forming a basin-wide circulation.

In general, the constant movement of water masses in the oceans is a complex system of cold and warm currents and countercurrents, both surface and deep.

The most famous for the inhabitants of America and Europe is, of course, the Gulf Stream. Translated from English, this name means Current from the Gulf. Previously, it was believed that this current begins in the Gulf of Mexico, from where it rushes through the Strait of Florida to the Atlantic. Then it turned out that the Gulf Stream takes out only a small fraction of its flow from this bay. Having reached the latitude of Cape Hatteras on the Atlantic coast of the United States, the current receives a powerful influx of water from the Sargasso Sea. This is where the actual Gulf Stream begins. A feature of the Gulf Stream is that when it enters the ocean, this current deviates to the left, while under the influence of the Earth's rotation it should deviate to the right.

The parameters of this mighty current are very impressive. The surface speed of water in the Gulf Stream reaches 2.0–2.6 meters per second. Even at a depth of up to 2 km, the speed of water layers is 10–20 cm/s. When leaving the Strait of Florida, the current carries 25 million cubic meters of water per second, which is 20 times more than the total flow of all the rivers of our planet. But after joining the flow of water from the Sargasso Sea (Antilles current), the capacity of the Gulf Stream reaches 106 million cubic meters of water per second. This powerful stream moves northeast to the Great Newfoundland Bank, and from here it turns south and, together with the Slope Current separated from it, is included in the North Atlantic water cycle. The depth of the Gulf Stream is 700–800 meters, and the width reaches 110–120 km. The average temperature of the surface layers of the current is 25–26 °С, and at depths of about 400 m it is only 10–12 °С. Therefore, the idea of the Gulf Stream as a warm current is created precisely by the surface layers of this stream.

Note another current in the Atlantic - the North Atlantic. It runs across the ocean to the east, towards Europe. The North Atlantic Current is less powerful than the Gulf Stream. The water flow here is from 20 to 40 million cubic meters per second, and the speed is from 0.5 to 1.8 km/h, depending on the location. However, the influence of the North Atlantic Current on the climate of Europe is very noticeable. Together with the Gulf Stream and other currents (Norwegian, North Cape, Murmansk), the North Atlantic Current softens the climate of Europe and the temperature regime of the seas washing it. Only one warm current, the Gulf Stream, cannot have such an impact on the climate of Europe: after all, the existence of this current ends thousands of kilometers from the coast of Europe.

Now back to the equatorial zone. Here the air heats up much stronger than in other parts of the world. The heated air rises, reaches the upper layers of the troposphere and begins to spread towards the poles. Approximately in the region of 28-30 ° northern and southern latitudes, having cooled, the air begins to descend. Increasingly new air masses flowing in from the equator create excess pressure in subtropical latitudes, while over the equator itself, due to the outflow of heated air masses, the pressure is constantly lowered. From areas of high pressure, air rushes to areas of low pressure, that is, to the equator. The rotation of the Earth around its axis deflects the air from the direct meridional direction to the west. So there are two powerful streams of warm air, called trade winds. In the tropics of the Northern Hemisphere, the trade winds blow from the northeast, and in the tropics of the Southern Hemisphere, from the southeast.

For simplicity of presentation, we do not mention the influence of cyclones and anticyclones in the temperate latitudes of both hemispheres. It is important to emphasize that the trade winds are the most stable winds on Earth, they blow constantly and cause warm equatorial currents that move huge masses of ocean water from east to west.

Equatorial currents are useful in navigation, helping ships to quickly cross the ocean from east to west. At one time, H. Columbus, not knowing anything about the trade winds and equatorial currents, felt their powerful effect during his sea voyages.

Based on the constancy of equatorial currents, the Norwegian ethnographer and archaeologist Thor Heyerdahl put forward a theory about the initial settlement of the islands of Polynesia by the ancient inhabitants of South America. To prove the possibility of sailing on primitive ships, he built a raft, which, in his opinion, was similar to the watercraft that the ancient inhabitants of South America could use when crossing the Pacific Ocean. On this raft, called "Kon-tiki", Heyerdahl, along with five other daredevils, made a dangerous voyage from the coast of Peru to the Tuamotu archipelago in Polynesia in 1947. For 101 days, he swam a distance of about 8 thousand kilometers along one of the branches of the southern equatorial current. The daredevils underestimated the power of the wind and waves and almost paid for it with their lives. Nearby, the warm equatorial current, driven by the trade winds, is not at all gentle, as one might think.

Let us briefly dwell on the characteristics of other currents in the Pacific Ocean. Part of the waters of the northern equatorial current in the Philippine Islands turns north, forming the warm current Kuroshio (Japanese for "Dark Water"), which is directed by a powerful stream past Taiwan and the southern Japanese islands to the northeast. The width of Kuroshio is about 170 km, and the depth of penetration reaches 700 m, but in general, this current is inferior to the Gulf Stream in fashion. About 36°N Kuroshio turns into the ocean, moving into the warm North Pacific Current. Its waters flow east, cross the ocean at about the 40th parallel, and warm the coast of North America all the way to Alaska.

The lapel of Kuroshio from the coast was noticeably affected by the influence of the cold Kuril current, approaching from the north. This current is called Oyashio (Blue Water) in Japanese.

Another remarkable current in the Pacific Ocean is El Niño (Spanish for "Baby"). This name is given because the El Niño current approaches the shores of Ecuador and Peru before Christmas, when the arrival of the baby Christ into the world is celebrated. This current does not occur every year, but when it nevertheless approaches the shores of the countries mentioned, it is not perceived otherwise than as a natural disaster. The fact is that too warm El Niño waters have a detrimental effect on plankton and fish fry. As a result, the catches of local fishermen are reduced tenfold.

Scientists believe that this treacherous current can also cause hurricanes, rainstorms and other natural disasters.

In the Indian Ocean, waters move along an equally complex system of warm currents, which are constantly influenced by monsoons - winds that blow from the ocean to the continent in summer, and in the opposite direction in winter.

In the band of the fortieth latitudes of the Southern Hemisphere in the World Ocean, winds constantly blow in the direction from west to east, which generates cold surface currents. The largest of these currents, where the waves are almost constantly raging, is the current of the West Winds, which circulates in the direction from west to east. The band of these latitudes from 40° to 50° on both sides of the equator is not accidentally called by sailors the “Roaring Forties”.

The Arctic Ocean is mostly covered in ice, but this did not make its waters at all motionless. The currents here are directly observed by scientists and specialists from drifting polar stations. For several months of drifting, the ice floe, on which the polar station is located, sometimes travels many hundreds of kilometers.

The largest cold current in the Arctic is the East Greenland Current, which carries the waters of the Arctic Ocean into the Atlantic.

In areas where warm and cold currents meet, phenomenon of deep water rise (upwelling), in which vertical flows of water carry deep water to the surface of the ocean. Together with them, nutrients rise, which are contained in the lower horizons of the water.

In the open ocean, upwelling occurs in areas where currents diverge. In such places, the ocean level drops and deep water inflow occurs. This process develops slowly - a few millimeters per minute. The most intense rise in deep waters is observed in coastal areas (10-30 km from the coastline). In the World Ocean, there are several permanent upwelling areas that affect the overall dynamics of the oceans and affect fishing conditions, for example: the Canary and Guinean upwellings in the Atlantic, the Peruvian and Californian upwellings in the Pacific Ocean, and the Beaufort Sea upwelling in the Arctic Ocean.

Deep currents and rises of deep waters are reflected in the nature of surface currents. Even such mighty currents as the Gulf Stream and Kuroshio, from time to time, either intensify or weaken. In them, the temperature of the water changes and deviations from the constant direction and huge swirls are formed. Such changes in sea currents affect the climate of the respective land regions, as well as the direction and distance of migration of certain species of fish and other animal organisms.

Despite the apparent randomness and fragmentation of sea currents, in fact they represent a certain system. The currents provide them with the same salt composition and unite all the waters into a single World Ocean.

Sea currents are constant or periodic flows in the thickness of the world's oceans and seas. There are constant, periodic and irregular currents; surface and underwater, warm and cold currents. Depending on the cause of the current, wind and density currents are distinguished.
The direction of the currents is influenced by the force of the Earth's rotation: in the Northern Hemisphere, the currents move to the right, in the Southern - to the left.
The current is called warm if its temperature is warmer than the temperature of the surrounding waters, otherwise, the current is called cold.

Density currents are caused by pressure differences that result from uneven distribution of seawater density. Density currents are formed in the deep layers of the seas and oceans. A striking example of density currents is the warm Gulf Stream.

Wind currents are formed under the action of winds, as a result of the friction forces of water and air, turbulent viscosity, pressure gradient, deflecting forces of the Earth's rotation, and some other factors. Wind currents are always superficial. Northern and South Trade winds, Western Winds, Intertrade Pacific and Atlantic.

1) Gulf Stream - a warm sea current in the Atlantic Ocean. In a broad sense, the Gulf Stream is a system of warm currents in the North Atlantic Ocean from Florida to the Scandinavian Peninsula, Svalbard, the Barents Sea and the Arctic Ocean.
Thanks to the Gulf Stream, the countries of Europe adjacent to the Atlantic Ocean have a milder climate than other regions at the same geographical latitude: masses of warm water heat the air above them, which is transferred to Europe by westerly winds. Deviations of air temperature from average latitude values in January reach 15–20 °C in Norway, and more than 11 °C in Murmansk.

2) The Peruvian current is a cold surface current in the Pacific Ocean. Moves from south to north between 4° and 45° south latitude along the western coasts of Peru and Chile.

3) The Canary Current is a cold and, subsequently, moderately warm sea current in the northeastern part of the Atlantic Ocean. Directed from north to south along the Iberian Peninsula and Northwest Africa as a branch of the North Atlantic Current.

4) The Labrador Current is a cold sea current in the Atlantic Ocean, flowing between the coast of Canada and Greenland and rushing south from the Baffin Sea to the Newfoundland Bank. There it meets the Gulf Stream.

5) The North Atlantic Current is a powerful warm ocean current that is the northeastern continuation of the Gulf Stream. Starts at the Great Newfoundland Bank. West of Ireland, the current is divided into two parts. One branch (the Canary Current) runs south and the other north along the coast of northwestern Europe. The current is believed to have a significant influence on the climate in Europe.

6) The cold California Current emerges from the North Pacific Current, moves along the coast of California from the northwest to the southeast, merges in the south with the North Tradewind Current.

7) Kuroshio, sometimes the Japan Current - a warm current off the southern and eastern coasts of Japan in the Pacific Ocean.

8) The Kuril current or Oyashio is a cold current in the northwest Pacific Ocean, which originates in the waters of the Arctic Ocean. In the south, near the Japanese Islands, it merges with Kuroshio. It flows along Kamchatka, the Kuriles and the Japanese islands.

9) The North Pacific Current is a warm ocean current in the North Pacific Ocean. It is formed as a result of the confluence of the Kuril Current and Kuroshio. Moves from the Japanese islands to the shores of North America.

10) Brazilian current - a warm current of the Atlantic Ocean off the eastern coast of South America, directed to the southwest.

P.S. To understand where the various currents are, study the set of maps. It will also be useful to read this article