Dead reckoning of the ship's path. The essence of graphical notation. Solution of the inverse problem
“There is a river in the ocean. It does not dry out even during the most severe droughts and does not overflow its banks during the largest floods. Its banks and bed are made of cold water, and its rapids are made of warm water.”. So in the middle of the 19th century. American scientist M. F. Mori wrote about the world’s most powerful warm ocean current Gulf Stream .
Ocean currents - horizontal movements of huge masses of water in a certain direction over long distances.
More often ocean currents arise under the influence of constant winds. Such currents are called winds. On both sides of the equator from the 30th latitude, constant trade winds blow in its direction, arising in the equatorial zone of all oceans. The currents caused by these winds are called trade winds(Fig. 80). Moving from east to west, trade wind currents, encountering the shores of continents, deviate to the north and south, and new currents are formed, called stock.
In temperate latitudes, these currents, under the influence of constant westerly winds and the force of the Earth's rotation, deviate to the east and are directed to the western shores of the continents. Then they return to 30 latitudes again as katabatic currents. So, north and south of the equator in zones 50 s. w. and 50° S. w. Two cycles of ocean water arise. In the Northern Hemisphere, currents move clockwise, in the Southern Hemisphere - vice versa. In the Northern Hemisphere, along the coast of Antarctica, under the influence of constant winds of moderate latitudes and the force of the Earth’s rotation, a powerful current of the Western Winds(Fig. 82). The name itself speaks about the reasons for its formation.
Distinguish warm And cold currents. If the temperature of the current water is higher than the temperature of the surrounding ocean waters, then it is considered warm, if below - cold. On maps, warm currents are indicated by red arrows, cold currents by blue arrows. Currents in the oceans significantly influence the climate and weather of the coastal parts of the continents. Cold ones reduce the temperature and amount of precipitation, while warm ones, on the contrary, increase it.
In shipping, it is important to take into account the strength and direction of currents. In the past they were used as "bottle mail". Material from the site
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| Rice. 82. Current of the Western Winds |
- Sea currents arise mainly under the influence of constant winds: trade winds and western temperate latitudes. They form two gyres in the World Ocean between 50 latitudes: in the Northern Hemisphere, the currents move clockwise, and in the Southern Hemisphere, vice versa.
- Currents are divided into cold and warm. On maps, warm currents are indicated by red arrows, cold currents by blue arrows.
- Currents influence the climate and weather of the coastal parts of the continents.
On this page there is material on the following topics:
World map with currents warm red cold blue
Warm katabatic current on the map
Message on the topic of the cold current of the westerly winds
California current wind or katabatic
Abstract on the topic of warm and cold flows
Questions about this material:
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 mid-latitudes of the southern hemisphere.
Dictionary of winds. - Leningrad: Gidrometeoizdat.
L.Z. Shit.
1983. See what “WIND CURRENT” is in other dictionaries: wind current
1983.- drift current A surface current that occurs as a result of the transfer of energy from the wind to surface ocean waters. Sometimes called Ekman drift or wind drift, the true response of surface waters is short-lived... ... Technical Translator's Guide
- Sea current caused by wind pressure on the surface layer of water. Syn.: wave current... Dictionary of Geography
Windshield- Panoramic windshield of a 1959 Edsel Corsair. Windshield, or windshield, is a transparent shield installed in front of the cabin of a car (or other vehicle) to protect the driver and passengers from oncoming... ... Wikipedia Technical Translator's Guide
wave current- Sea current caused by wind pressure on the surface layer of water. Syn.: wind current... Technical Translator's Guide
monsoon current
- Surface (to a depth of about 200 m) wind current in oceans and seas with seasonal changes in direction caused by monsoons... Wind (drift) ocean current south of 65° S. sh., arising under the influence of the prevailing eastern winds. Width of P. a. t. about 250 miles. It covers Antarctica in an almost continuous ring... Dictionary of winds Collier's Encyclopedia
lake- natural pond in a depression earth's surface(lake basin). The lakes are fed atm. precipitation, surface and underground runoff. According to their water balance, lakes are divided into flowing lakes (those with a river or rivers flowing from them) and drainage lakes (without… Geographical encyclopedia
sea currents- translational movements of the waters of the World Ocean caused by the wind and the difference in their pressures at 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- Current in lower layers water, compensating surface wind current... Technical Translator's Guide
Mariners learned about the presence of ocean currents almost as soon as they began to plow the waters of the World Ocean. True, the public paid attention to them only when, thanks to the movement of ocean waters, many great geographical discoveries were made, for example, Christopher Columbus sailed to America thanks to the North Equatorial Current. After this, not only sailors, but also scientists began to pay close attention to ocean currents and strive to study them as best and deeply as possible.
Already in the second half of the 18th century. the sailors studied the Gulf Stream quite well and successfully applied the acquired knowledge in practice: from America to Great Britain they walked with the current, and in the opposite direction they kept a certain distance. This allowed them to stay two weeks ahead of ships whose captains were not familiar with the area.
Ocean or sea currents are large-scale movements of water masses in the World Ocean at speeds from 1 to 9 km/h. These streams do not move chaotically, but in a certain channel and direction, which is the main reason why they are sometimes called rivers of the oceans: the width of the largest currents can be several hundred kilometers, and the length can reach several thousand.
It has been established that water flows do not move straight, but deviate slightly to the side and are subject to the Coriolis force. In the Northern Hemisphere they almost always move clockwise, in the Southern Hemisphere it’s the other way around.. 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 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 different places in the ocean and even its physical and 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 the huge flows 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 of them, when colliding with continents and islands, turn to the north or south.
Warm and cold water currents
It must be taken into account that the concepts of “cold” or “warm” currents are conditional definitions. So, despite the fact that the temperature of the water flows of the Benguela Current, which flows along the Cape of Good Hope, is 20°C, it is considered cold. But the North Cape Current, which is one of the branches of the Gulf Stream, with temperatures from 4 to 6 ° C, is warm.
This happens because cold, warm and neutral currents got their names based on a comparison of the temperature of their water with the temperature of the surrounding ocean:
- If the temperature indicators of the water flow coincide with the temperature of the surrounding waters, 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 high river flows, 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 tropical to subpolar latitudes, for example, the Gulf Stream.
Main water flows
On this moment Scientists have recorded about fifteen main ocean water flows in the Pacific, fourteen in the Atlantic, seven in the Indian and four in the Arctic Ocean.
It is interesting that all currents of the Arctic Ocean move at the same speed - 50 cm/sec, three of them, namely the West Greenland, West Spitsbergen and Norwegian, are warm, and only the East Greenland is a cold current.
But almost all oceanic currents of the Indian Ocean are warm or neutral, with the Monsoon, Somali, Western Australian and Cape Agulhas current (cold) moving at a speed of 70 cm/sec, the speed of the rest varies from 25 to 75 cm/sec. The water flows of this ocean are interesting because, together with the seasonal monsoon winds, which change their direction twice a year, the oceanic rivers also change their course: in winter they mainly flow to the west, in summer - to the 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 flows located in the north move clockwise, in the south - counterclockwise.
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 find themselves in the Barents Sea, they enter the Arctic Ocean, where they cool and turn south in the form of the cold Greenland Current, after which at some stage they deviate to the west and again join the Gulf Stream, forming a vicious circle.
The currents of the Pacific Ocean are mainly in a latitudinal direction 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 much of our planet.
For example, trade wind water currents transport warm waters from the western tropical coasts to the eastern ones, which is why the western part of the Pacific Ocean is much warmer in the tropical zone opposite side. But in the temperate latitudes of the Pacific Ocean, on the contrary, the temperature is higher in the east.
Deep Currents
For quite a long time, scientists believed that deep ocean waters were almost motionless. But soon special underwater vehicles discovered both slow and fast-flowing water streams at great depths.
For example, under the Equatorial Current of the Pacific Ocean at a depth of about one hundred meters, scientists have identified the underwater Cromwell Current, moving eastward at a speed of 112 km/day.
Soviet scientists found a similar movement of water flows, but in the Atlantic Ocean: the width of the Lomonosov Current is about 322 km, and maximum speed 90 km/day was recorded at a depth of about one hundred meters. After this, another underwater flow was discovered in the Indian Ocean, although its speed turned out to be much lower - about 45 km/day.
The discovery of these currents in the ocean gave rise to new theories and mysteries, the main one of which is the question of why they appeared, how they were formed, and whether the entire area of the ocean 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 can hardly 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 driven by solar energy. This machine creates a constant exchange of water between the surface and deep layers of the ocean, providing it with oxygen dissolved in the water and influencing the life of marine inhabitants.
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, resulting in the organization of a food chain. Plankton is eaten by small fish, which, in turn, become prey to larger fish, birds, and marine mammals, which, given 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 ambient temperature 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 disastrous - a huge amount of dead small fish ends up in the ocean, large fish leave, fishing stops, birds leave their nesting places.
