The course of westerly winds on the map of Antarctica. ocean currents

The air masses surrounding us are in continuous motion: up and down, horizontally. The horizontal movement of air is what we call wind. Wind currents are formed according to their own specific laws. To characterize them, indicators such as speed, strength and direction are used.

The winds of different climatic regions have their own features and characteristics. The temperate latitudes of the Northern and Southern Hemispheres are blown by westerly winds.

Constants and variables

Wind direction determines areas of high and low pressure. Air masses move from areas of high pressure to areas of low pressure. The direction of the wind also depends on the action of the earth's rotation: in the northern hemisphere, the flows are corrected to the right side, in the southern hemisphere - to the left. Air flows can be either constant or variable.

Western winds of temperate latitudes, trade winds, northeast and southeast belong to the group of constants. If the trade winds are called the winds of the tropics (30 o N - 30 o S), then westerly winds prevail in temperate latitudes from 30 o to 60 o in both hemispheres. In the Northern Hemisphere, these air currents deviate to the right.

In addition to constant winds, there are variable or seasonal winds - breezes and monsoons, as well as local winds that are typical only for a particular region.

The course of the West Winds

Air, moving in a certain direction, has the ability to carry huge masses of water in the ocean, creating strong currents - rivers among the oceans. Wind currents are called wind currents. In temperate latitudes, westerly winds and the rotation of the earth direct surface currents towards the western shores of the continents. In the northern hemisphere they move clockwise, in the southern hemisphere they move counterclockwise. In the Southern Hemisphere, the action of the wind and the earth's rotation have created a strong current of West Winds along the coasts of Antarctica. This is the most powerful ocean current that encircles the entire globe from west to east in the area between 40 o and 50 o south latitude. This current serves as a barrier separating the southern waters of the Atlantic, Indian and Pacific Oceans from the cold waters of the Antarctic.

wind and climate

Western winds have an impact on the climate of a large area of ​​the Eurasian continent, especially on that part of it that is located in the temperate zone. With the breeze of the West, coolness comes to the continent in the midst of summer heat and thaw in winter. It is the winds from the west in cooperation with the warm ocean current that explain the fact that the climate of the north-west of Europe is much warmer than the same latitudes of North America. With advancement deep into the continent to the east, the influence of the Atlantic decreases, but the climate becomes completely continental only beyond the Ural Range.

In the Southern Hemisphere, violent winds from the west are not hindered by any obstacles in the form of continents and mountains, they are free and free: they storm, fight ships, rush east at high speed.

Who is friends with the wind

Indomitable news is especially familiar to sailors on the routes Cape of Good Hope - New Zealand - Cape Horn. Having picked up a passing sailboat, they can disperse it faster than a diesel ship. Sailors call western winds gallant in the Northern Hemisphere and roaring forties in the Southern.

Westerly winds also caused a lot of trouble to the first aviators. They were allowed to fly from America to Europe, as they were on the way. Pilots passed the route without problems. The situation with the flight from Europe to America was quite different. Of course, no wind is a hindrance to modern supersonic liners, but in the 20-30s of the nineteenth century it turned out to be a significant obstacle.

So the French pilots Nengesier and Colli in 1919 made a historic flight across the Atlantic Ocean on the route Newfoundland - Azores - Iceland. But the same way in the opposite direction ended tragically. The pilots intended to repeat the famous path of Columbus by air, only 34 years later the wreckage of their aircraft was discovered on the coast of the United States.

The tragedy is explained by the fact that strong winds significantly delayed the aircraft, and there was simply not enough fuel to reach the destination.

The Soviet pilots Gordienko and Kokkinaki were the first to defeat the oncoming waves in 1939, successfully overcoming the French route.

In the Australo-Oceanian region, the sea prevails over the land. The discovery and settlement of the islands of Oceania proceeded along sea routes, and in order to understand in what direction and in what ways this historical process proceeded, it is first of all necessary to form a clear idea of ​​the currents and winds of the Pacific Ocean and the seas washing the Australian mainland.

In the Pacific Ocean, sea currents form two great rings - one in the northern, the other in the southern hemisphere. In the tropical latitudes of the Northern Hemisphere, the northeast trade winds drive the waters of the warm North Trade Wind Current to the west. At the Philippines, this current turns north and goes to the eastern shores of Japan, here taking the name Kuroshio. To the east of the island of Honshu, Kuroshio passes into the North Pacific Current, which, in a band of persistent westerly winds, crosses the ocean from west to east in the forties. At the California coast, it turns south and merges with the North Tradewind. Thus, in the northern hemisphere, a ring is formed, within which the waters move clockwise.

In the tropical zone of the southern hemisphere, the southeast trade winds cause a warm South Trade Wind Current, which follows the same direction as the North Trade Wind, from east to west. The southern branches of the South Trade Wind current off the eastern coast of Australia deviate to the south and in the fortieth latitudes of the southern hemisphere merge with the West Winds, which drives huge masses of icy waters from west to east. This cold current breaks into the narrow gates of the Drake Passage, which separates Antarctica from Tierra del Fuego. However, the cold oceanic river does not fit into the narrow throat of the strait and, deviating to the north, rushes along the Chilean coast, forming a powerful Peruvian current. The Great Southern Ring closes at the Galapagos Islands, where the jets of the cold Peruvian Current join the warm South Equatorial Current. In the southern ring, unlike the northern one, the water circulates counterclockwise.

Between the northern and southern rings in the equatorial zone of calm, the Pacific Ocean crosses from west to east in the range of 4-10 ° N. latitude. the warm Equatorial countercurrent, also called the Equatorial countercurrent. It runs against the prevailing wind in some areas. Both trade winds and the course of the West Winds are very stable, since both the trade winds and winds in the forties of the southern hemisphere constantly blow in the same directions.

Much less stable is the Equatorial countercurrent, whose strip is often occupied by trade winds blowing in the opposite direction, and long-term calms, although, as studies of recent years show, westerly winds and certain seasons are quite constant.

The winds and currents are very unstable within the southern ring, that is, between the South Equatorial Current and the course of the West Winds. In this area, which, depending on the time of year, captures a strip of the ocean in the range from 15° to 40-45° S, branches of these powerful currents and unstable winds blowing from different points of view form gyres of large and small radius. The wind regime and the regime of currents in the seas of Western Oceania, near the coasts of New Guinea, the Solomon Islands and the Great Barrier Reef, as well as on the far northern periphery of the West Winds current (thirtieth latitudes) and between Easter Island and the Chilean coast are unstable.

Off the eastern shores of New Guinea and the Solomon Islands, currents in winter (June to September) flow from the southeast to the northwest, and in the summer months (November to March) they go in the opposite direction, subject to the monsoon regime, which captures in tropical latitudes throughout the Indian Ocean and the western Pacific. Off the coast of New Zealand, the winds circulate clockwise in winter, and in the summer they follow in the opposite direction, opposite to the direction of the prevailing currents.

Thus, in the southern half of the Pacific Ocean, there are only two stable and powerful currents - the South Trade Wind and the West Winds, which are through waterways. Unlike land highways, great sea currents are “self-propelled roads”.

Consider first the South Equatorial Current. On average, his speed is 18 miles per day. The trade winds blow almost continuously at a speed of five or six meters per second, and the sky in their zone is almost always blue and clear. Not without reason, having made the transition in the jet of this current from the shores of the New World to East Asia, Magellan called the newly discovered ocean the Pacific. The South Trade Wind is an ideal transoceanic route, but this route is favorable only for one-way traffic - from east to west (and southwest), from the northern coasts of Peru to the shores of Asia (and along the side branch to the islands of southwestern Oceania). Does it follow from this that in the belt of the South Trade Wind current two-way traffic, if not through, then "local" is absolutely impossible. Of course not. Wind circulation, especially in the western part of this belt, with a fairly advanced technique of sailing equipment and a high level of navigational art, allows navigation at any angle to the main direction of this current, and sometimes against it. In addition, to the north of the South Equatorial Current passes, capturing the southern periphery of the Caroline Islands and the Marshall Islands, the Equatorial countercurrent, which is not very stable, however, is favorable for navigation in an easterly direction.

From the Marshall Islands, the path south along the island garland of the Gilbert archipelago and further southeast to the islands of central Polynesia is very difficult, although it is possible for fairly stable ships, especially in summer, when winds often blow in these waters from the northwest rhumbs.

Thus, it was possible to get from the islands of the Malay Archipelago to Polynesia, following first to the east, along the Caroline Ridge, and then to the south, along the long chain of the Gilbert archipelago. The second route from the Malay Archipelago to Polynesia runs along the northern coast of New Guinea and further past the Solomon Islands and the New Hebrides to the islands of Fiji, Tonga and Samoa.

The northwest monsoon blows off New Guinea and the Solomon Islands during the summer months. They are far from as stable as the winter southeast trade winds, usually accompanied by showers and fogs, and often, reaching storm strength, are replaced by dead calms. However, for navigation in the east and southeast directions, the summer monsoons create a rather favorable, albeit unstable, situation in these waters.

The second oceanic highway - the course of the West Winds - runs in the fortieth latitudes of the southern hemisphere. This is a through route from Australia and New Zealand to the seas washing the southern tip of South America. But the current of the West Winds crosses the Pacific Ocean far south of the islands of tropical Oceania. In addition, the fortieth latitudes of the southern hemisphere in terms of climatic conditions correspond to the fiftieth, if not even the sixtieth, latitudes of the northern hemisphere. Therefore, the course of the West Winds could not in ancient times connect Oceania with South America, especially South America with Oceania. It received the value of a through trans-Pacific highway only after the second expedition of Cook when this path was opened to European ships.

Major Currents in the Pacific Ocean

As already noted, a significant part of Oceania (and especially its southeastern islands) lies outside the South Trade Wind Current, inside the great southern ring.

Near the archipelagos of southeastern Oceania, changing each other in the most unexpected way, northeast, east and southeast winds blow; in winter, northerly winds are added and the frequency of easterly winds increases. To the southeast of the Tuamotu Archipelago, in the space between the 140th and 90th meridians in subtropical latitudes, the winds describe a complete circulation, and they are especially unstable in winter. To the south of Easter Island, the icy breath of high latitudes is already felt; here in winter the frequency of south winds reaches 40-50%.

Unstable winds, often of gale force, have a very complex effect on currents. On the map of sea currents throughout this area (with the exception of the coastal strip near the South American mainland), currents of different and sometimes directly opposite directions are shown. Directly off the Chilean and Peruvian coasts, steady southerly and southwesterly winds prevail, which drive the cold waters of the Peruvian current northward. Consequently, in Eastern Oceania, inside the ring formed by the South Trade Wind Current, the Western Wind Current and the Peruvian Current, the conditions for long-distance and especially through navigation both in the western and eastern directions are very unfavorable.

Pilots of the Pacific Highly Recommend all navigators, when crossing the Pacific Ocean, keep either the South Equatorial Current (routes South America - Australia; South America - Southeast Asia), or the current of the West Winds (route Australia - South America).

Speaking of currents and winds, we deliberately did not mention Australia for the time being. The Australian mainland is washed not only by the Pacific, but also by the Indian Ocean and its two seas - Timor and Arafura. And in the southern half of the Indian Ocean, between the coasts of Africa and Australia, sea currents form a special closed ring in which water circulates according to the same laws as in the rings of the great currents of the South Pacific Ocean.

At approximately the same latitudes as the Pacific Ocean, the Indian Ocean has a steady, warm South Equatorial Current that follows from east to west. Off the coast of Madagascar, it bifurcates. Its southern branch turns to the south and southeast and merges with the course of the West Winds in the fortieth latitudes. In the thirtieth and fortieth latitudes, approximately at the 80th meridian, a stable and cold West Australian Current departs from the West Winds to the northeast, which reaches the western coast of Australia and then flows into the South Equatorial Current. Thus, through routes go from the coast of Africa to the western and southern coasts of Australia.

It is no coincidence that after the Dutchman Brouwer discovered the Western Australian Current in 1611, the western and southern coasts of Australia were soon put on the map by compatriots and successors of Brouwer.

The East Australian water area presents a completely different picture. The northeastern coast of Australia is bordered along its entire length by the Great Barrier Reef - a coral palisade more than 2 thousand km long. In the narrow, shallow passages between the coast of the mainland and the chain of coral reefs, local, predominantly tidal currents operate, and therefore swimming off the northeastern coast of Australia is fraught with great dangers.

More favorable navigation conditions are in the Tasman Sea, off the southeastern coast of the Australian mainland, which is devoid of coral barriers. Here the warm East Australian current passes from north to south, which then flows into the course of the West Winds. But in order to enter, following from the north, along the eastern coast of Australia, into the Tasman Sea, it is necessary to overcome the terrible Coral Sea. Therefore, before the appearance of Europeans in Australian waters, and in the age of great geographical discoveries, the eastern, most fertile part of the fifth continent was a completely unknown land for the rest of the world. The green shores of New South Wales were discovered more than a century and a half after the Dutch reached the desert coast of Western Australia.

In the seas washing the northern shores of Australia, Timor and Arafura in winter (April - August), southeast monsoons blow, and in summer (September - March) - southwest monsoons. This is an area of ​​stable monsoons, winds that have a huge impact on the climate in the northern part of the Indian Ocean and in South Asia. Monsoons also determine the direction of the prevailing currents in the Timor and Arafura seas.

In addition to winds and currents, the navigational capabilities of ships of all types are also determined by the conditions of navigation in coastal waters. After all, we must anchor in these waters, we must land on the shores of these lands. And in the conditions of Oceania, this is associated with enormous, sometimes insurmountable difficulties, and the greatest dangers are fraught with windward shores of volcanic and especially coral islands.

Here is a far from complete list of "trouble and evil" awaiting sailors in the coastal waters of the oceanic islands:

1. reefs. Flooded and semi-flooded at high tide, invisible at night and in fog. Solid reef rings of coral atolls (narrow passages in these rings are extremely dangerous); "dragon's teeth" scattered along the coastline; "placers" of underwater rocks in interisland straits.

2. Winds. Trade winds and sea breezes on windward shores, southerly and western winds on leeward. Calms and breezes with strong coastal currents. Cyclones in the seas of Western Oceania.

3. currents. Tidal currents along barrier reefs, along high coasts, in bays, inter-island straits and in narrow reef-studded passages. Coastal currents driven by erratic winds, often changing direction suddenly.

The furious rumble of the surf and foamy ridges are dangerous signs of windward shores. In the strip of trade winds, surf and excitement create enormous difficulties for guiding ships to these shores. But the lee shores are no less dangerous.

To the south of the southern group of the Cook Islands and the Tuamotu archipelago, the sea is constantly experiencing waves from the southwestern points. It is caused by the steady westerly winds of the "roaring forties", which have a place to roam in the ocean. Pilots of the Pacific Ocean indicate, for example, that for this reason “on the low islands of the Tuamotu archipelago, a serious obstacle to landing is a strong roll on the shores leeward with respect to the trade winds; it is often more dangerous to seek refuge on leeward shores than on windward ones.

We will never know how many light-winged boats and clumsy rafts perished on the approaches to the treacherous shores of the islands of the South Seas. In ship registers, however, one can find data on shipwrecks that have occurred over the past century and a half, and these losses are calculated in multiple figures. Particularly dangerous are the waters of the Tuamotu Archipelago, the Marquesas, the Central Polynesian Sporades, the Solomon Islands, New Caledonia and northeastern Australia.

The Gulf Stream is the largest warm current

The world ocean absorbs a wide variety of currents, ranging from the smallest to the largest. These currents bypass the continents and form 5 large rings. The circulation, which is closely connected with the general circulation of the atmosphere, is called the system of currents in the oceans. Currents are divided into cold and warm. Perhaps everyone has heard of the most famous ocean current - the Gulf Stream, but what do we know about other ocean currents?

The Gulf Stream is recognized as the largest warm current, it flows through the Gulf of Mexico, heading to the Northern Hemisphere. This current carries with it the warm waters of the Atlantic Ocean, due to which a mild climate is created in Europe. And the most powerful current is the current of the West winds, or, as it is also called, the Antarctic circumpolar, which carries water from West to East.

The course of the westerly winds

The West Wind Drift circles the entire globe, passing through the Atlantic, Pacific and Indian oceans. In these oceans, branchings appear from the largest current, such as the Bengal, Peruvian and West Australian currents. In the upper layer, the water temperature is 12-15 °C in the northern part and 1-2 °C in the southern part of the current. This is the most powerful ocean current, its average water flow is equivalent to 125 Sv.

The wind current that circles the globe

The most powerful current got its name due to the blowing winds from west to east in the spaces of the Southern Hemisphere. The current of the West Winds is the only one of its kind that bypasses the entire globe. The width of this current is about 1,000 km, and the length is about 30,000 km. Such a powerful stream overcomes the entire thickness of the waters in various places of the World Ocean, and even the continents do not weaken its movement.

The winds that cause the current get their incredible strength south of the 40th parallel. Hence the name of the Antarctic Circumpolar Current zone, as the "roaring forties", because of the frequent and ferocious storms. It is in the area of ​​\u200b\u200bthe most powerful current that the Southern Ocean is located.

Western winds flow

current in the Southern Hemisphere, heading from W. to E. approximately between 40 ° and 55 ° S. sh. Due to prevailing westerly winds. It encircles the globe, crossing the Atlantic, Indian and Pacific oceans, in which the cold Benguela, West Australian and Peruvian currents branch off from it. Speed ​​1-2 km/h The water temperature varies from 12 to 15 °С in the northern part of the current, from 1 to 2 °С in the southern part; salinity, respectively, from 35.05 0/00 to 33.9-34.05 0/00. On the northern and southern borders of the Z. century. m., formed by zones of convergence of surface currents, large masses of floating algae accumulate in places.

Great Soviet Encyclopedia. - M.: Soviet Encyclopedia. 1969-1978 .

See what "Western winds flow" in other dictionaries:

The Antarctic Surface Current circles the globe between 40 and 55°S. sh. Length up to 30,000 km, width up to 1000 km. Called dominant in these latitudes west. winds, t changes from 12 15 ° С in the north to 1 2 ° С in the south. In the Atlantic from it ... ... Geographic Encyclopedia

- (Antarctic Circumpolar Current) surface current in the Southern Hemisphere, approximately between 40 and 55.S. sh. Encircles the globe, crossing the Atlantic, Indian and Pacific oceans, in which the cold Benguela, ... ... Big Encyclopedic Dictionary

- (Antarctic Circumpolar Current), surface current in the Southern Hemisphere, approximately between 40 and 55ºS. sh. Encircles the globe, crossing the Atlantic, Indian and Pacific oceans, in which the cold Benguela, ... ... encyclopedic Dictionary

westerly winds- The current in the World Ocean, encircling the Southern Hemisphere between Antarctica and the southern extremities of three other continents, where the resulting water transport is directed to the east. Syn.: southern oceanic ring... Geography Dictionary

COURSE OF WESTERN WINDS- ocean current north of 60°S sh., carrying surface waters mainly to the east and northeast. Covers the area of ​​the oceans between 40 and 60 ° S. sh., the width of the stream reaches 800 miles, only in the Drake Strait up to 300 miles. Average ... ... Dictionary of winds

See Antarctic Circumpolar Current. Geography. Modern illustrated encyclopedia. Moscow: Rosman. Under the editorship of prof. A.P. Gorkina. 2006 ... Geographic Encyclopedia

- ... Wikipedia