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 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) Peruvian current - cold surface current in 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 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
wind currents currents of surface waters of oceans and seas, resulting from the action of wind on the water surface. Wind flow develops under the combined influence of friction forces, turbulent viscosity, pressure gradient, deflecting forces of the Earth's rotation, and so on. The wind component of these currents, without taking into account the pressure gradient, is called the drift current. Under conditions of winds that are stable in direction, powerful wind currents develop, such as the North and South Trade-wind currents, the course of westerly winds, and others. N. S. Lineikin, American G. Stoml.
Big soviet encyclopedia. - M.: Soviet Encyclopedia. 1969-1978 .
See what "Wind currents" are in other dictionaries:
DRIFT CURRENTS- wind currents in the ocean caused by sustained long winds. They are distinguished by the constancy of annual characteristics with a noticeable dissimilarity of seasonal ones (Gulf Stream, Kuroshio, trade wind drift currents, etc.). Ecological encyclopedic ... ... Ecological dictionary
sea currents- translational movements of the waters of the World Ocean, caused by the wind and the difference in their pressures on the same horizons. Currents are the main type of water movement and have a huge impact on the distribution of temperature, salinity and ... ... Marine encyclopedic reference book
Translational movements of water masses in the oceans and seas, part of the general water cycle of the oceans. They are caused by the action of the friction force between water and air, pressure gradients that occur in water, and the tide-forming forces of the Moon and the Sun. On ... ... Marine Dictionary
Currents in reservoirs caused by the action of the wind. See wind currents...
DRIFT CURRENTS- wind currents, temporary, periodic or permanent, arising on the surface of the water under the influence of wind. They deviate from the direction of the wind in the northern hemisphere to the right by an angle of 30 45 °. In shallow basins, the angle is much smaller, but on ... ... Wind Dictionary
- ... Wikipedia
Map of currents of the world ocean in 1943 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. In ... ... Wikipedia
- (ocean currents), translational movements of water masses in the seas and oceans, due to various forces (the action of the friction force between water and air, pressure gradients arising in water, tide-forming forces of the Moon and the Sun). On the… … encyclopedic Dictionary
Gradient currents, currents in the seas and oceans, excited by horizontal pressure gradients, which are due to the uneven distribution of the density of sea water. Along with wind currents (See Wind currents), constant P. ... ... Great Soviet Encyclopedia
WIND CURRENT - an ocean current caused by wind over the water surface, especially in those parts of the World Ocean where the wind regime is quite stable, for example, in the middle latitudes of the southern hemisphere.
Dictionary of winds. - Leningrad: Gidrometeoizdat. L.Z. Proh . 1983
See what "WIND CURRENT" is in other dictionaries:
wind current- drift current A surface current that occurs as a result of the transfer of energy from the wind to the surface ocean waters. Sometimes referred to as the Ekman drift or wind drift, the true reaction of surface water is transient... ... Technical Translator's Handbook
wind current- Sea current caused by wind pressure on the surface layer of water. Syn.: wave flow… Geography Dictionary
Windshield- Panoramic windshield of a 1959 Edsel Corsair. The windshield, or windshield, is a transparent shield installed in front of the cab of a car (or other vehicle) to protect the driver and passengers from an oncoming ... ... Wikipedia
wave current- Sea current caused by wind pressure on the surface layer of water. Syn.: wind current… Geography Dictionary
monsoon current- Surface (down to a depth of about 200 m) wind current in the oceans and seas with a seasonal change in direction caused by monsoons ... Geography Dictionary
Wind (drift) ocean current south of 65°S sh., arising under the influence of the prevailing east winds. P.'s width and. t. about 250 miles. It covers Antarctica in an almost continuous ring ... Wind Dictionary
LAKE- a body of water surrounded by land. The lakes range in size from very large, such as the Caspian Sea and the Great Lakes to North America, to tiny reservoirs of several hundred square meters or even less. The water in them can be fresh, ... ... Collier Encyclopedia
lake - natural reservoir in a recess earth's surface(lake basin). Lakes feed on atm. precipitation, surface and underground runoff. According to the water balance, lakes are divided into flowing (having a river or rivers flowing from them) and endorheic (not having ... Geographic Encyclopedia
sea currents- translational movements of the waters of the World Ocean, caused by the wind and the difference in their pressures on the same horizons. Currents are the main type of water movement and have a huge impact on the distribution of temperature, salinity and ... ... Marine encyclopedic reference book
bottom countercurrent- The current in the lower layers of the water, compensating for the surface wind current ... Geography Dictionary
Navigators learned about the presence of ocean currents almost immediately, as soon as they began to surf the waters of the oceans. True, the public paid attention to them only when, thanks to the movement of ocean waters, many great geographical discoveries, for example, Christopher Columbus sailed to America thanks to the North Equatorial Current. After that, not only sailors, but also scientists began to pay close attention to ocean currents and strive to explore them as best and as deeply as possible.
Already in the second half of the XVIII century. sailors studied the Gulf Stream quite well and successfully applied their knowledge in practice: they went with the flow from America to Great Britain, and kept a certain distance in the opposite direction. This allowed them to be two weeks ahead of ships whose captains were not familiar with the terrain.
Oceanic or sea currents are large-scale movements of the water masses of the World Ocean at a speed of 1 to 9 km / h. These streams do not move randomly, but in a certain channel and direction, which is the main reason why they are sometimes called the rivers of the oceans: the width of the largest currents can be several hundred kilometers, and the length can reach more than one thousand.
It has been established that water flows do not move straight, but deviating slightly to the side, they obey the Coriolis force. In the Northern Hemisphere they almost always move clockwise, in the Southern Hemisphere it is vice versa.. At the same time, currents located in tropical latitudes (they are called equatorial or trade winds) move mainly from east to west. The strongest currents were recorded along the eastern coasts of the continents.
Water flows do not circulate on their own, but they are set in motion by a sufficient number of factors - the wind, the rotation of the planet around its axis, the gravitational fields of the Earth and the Moon, the bottom topography, the outlines of continents and islands, the difference in temperature indicators of water, its density, depth in various places of the ocean and even its physico-chemical composition.
Of all types of water flows, the most pronounced are the surface currents of the World Ocean, the depth of which is often several hundred meters. Their occurrence was influenced by trade winds, constantly moving in tropical latitudes in a west-east direction. These trade winds form huge streams of the North and South Equatorial currents near the equator. A smaller part of these flows returns to the east, forming a countercurrent (when the movement of water occurs in the opposite direction from the movement of air masses). Most, colliding with the continents and islands, turns to the north or south.
Warm and cold water streams
It must be taken into account that the concepts of "cold" or "warm" currents are conditional definitions. So, despite the fact that the temperature indicators of the water flows of the Benguela Current, which flows along the Cape of Good Hope, are 20 ° C, it is considered cold. But the North Cape Current, which is one of the branches of the Gulf Stream, with temperatures ranging from 4 to 6 ° C, is warm.
This happens because the cold, warm and neutral currents got their names based on a comparison of the temperature of their water with the temperature indicators of the ocean surrounding them:
- If the temperature indicators of the water flow coincide with the temperature of the waters surrounding it, such a flow is called neutral;
- If the temperature of the currents is lower than the surrounding water, they are called cold. They usually flow from high latitudes to low latitudes (for example, the Labrador Current), or from areas where, due to the large flow of rivers, ocean water has a reduced salinity of surface waters;
- If the temperature of the currents is warmer than the surrounding water, then they are called warm. They move from the tropics to subpolar latitudes, such as the Gulf Stream.
Main water flows
At the moment, scientists have recorded about fifteen major oceanic water flows in the Pacific, fourteen in the Atlantic, seven in the Indian and four in the Arctic Ocean.
It is interesting that all the currents of the Arctic Ocean move at the same speed - 50 cm / s, three of them, namely the West Greenland, West Svalbard and Norwegian, are warm, and only the East Greenland belongs to the cold current.
But almost all the oceanic currents of the Indian Ocean are warm or neutral, while the Monsoon, Somali, West Australian and the Cape of Needles (cold) move at a speed of 70 cm / s, the speed of the rest varies from 25 to 75 cm / s. The water flows of this ocean are interesting because, along with the seasonal monsoon winds, which change their direction twice a year, ocean rivers also change their course: in winter they mainly flow west, in summer - east (a phenomenon characteristic only of the Indian Ocean). ).
Since the Atlantic Ocean stretches from north to south, its currents also have a meridional direction. Water streams located in the north move clockwise, in the south - against it.
A striking example of the flow of the Atlantic Ocean is the Gulf Stream, which, starting in the Caribbean Sea, carries warm waters to the north, breaking up into several side streams along the way. When the waters of the Gulf Stream end up in the Barents Sea, they enter the Arctic Ocean, where they cool and turn south in the form of a cold Greenland current, after which at some stage they deviate to the west and again adjoin the Gulf Stream, forming a vicious circle.
The currents of the Pacific Ocean are mainly latitudinal and form two huge circles: northern and southern. Since the Pacific Ocean is extremely large, it is not surprising that its water flows have a significant impact on most of our planet.
For example, trade winds move warm water from the western tropical coasts to the eastern ones, which is why the western part of the Pacific Ocean in the tropical zone is much warmer than the opposite side. But in the temperate latitudes of the Pacific Ocean, on the contrary, the temperature is higher in the east.
deep currents
Enough long time scientists believed that the deep ocean waters are almost motionless. But soon, special underwater vehicles discovered both slow and fast-flowing water flows at great depths.
For example, under the Equatorial Pacific Ocean at a depth of about one hundred meters, scientists have identified the Cromwell underwater stream, moving eastward at a speed of 112 km / day.
A similar movement of water flows, but already in the Atlantic Ocean, was found by Soviet scientists: the width of the Lomonosov current is about 322 km, and the maximum speed of 90 km / day was recorded at a depth of about one hundred meters. After that, another underwater stream was discovered in Indian Ocean, however, its speed was much lower - about 45 km / day.
The discovery of these currents in the ocean gave rise to new theories and mysteries, the main of which is the question of why they appeared, how they formed, and whether the entire ocean area is covered by currents or there is a point where the water is still.
The influence of the ocean on the life of the planet
The role of ocean currents in the life of our planet cannot be overestimated, since the movement of water flows directly affects the planet's climate, weather, and marine organisms. Many compare the ocean to a huge heat engine powered by solar energy. This machine creates a continuous water exchange between the surface and deep layers of the ocean, providing it with oxygen dissolved in water and affecting the life of marine life.
This process can be traced, for example, by considering the Peruvian Current, which is located in the Pacific Ocean. Thanks to the rise of deep waters, which lift phosphorus and nitrogen upward, animal and plant plankton successfully develop on the ocean surface, as a result of which the food chain is organized. Plankton is eaten by small fish, which, in turn, becomes a victim of larger fish, birds, marine mammals, which, with such food abundance, settle here, making the region one of the most highly productive areas of the World Ocean.
It also happens that a cold current becomes warm: the average temperature environment rises by several degrees, causing warm tropical showers to fall on the ground, which, once in the ocean, kill fish accustomed to cold temperatures. The result is deplorable - a huge amount of dead small fish ends up in the ocean, large fish leave, fishing stops, birds leave their nests. As a result, the local population is deprived of fish, crops that were beaten by downpours, and profits from the sale of guano (bird droppings) as fertilizer. It can often take several years to restore the former ecosystem.