Is there a 5 ocean. The Southern Ocean is officially recognized as a geographical community or is it just a convention
In 2000, the International Hydrographic Organization adopted a division into five oceans, highlighting South ocean from the Atlantic, Indian and Pacific. In its southern part, the boundaries between the three oceans are very arbitrary, while the waters adjacent to Antarctica have their own specifics, and are also united by the Antarctic circumpolar current.
In the Soviet and Russian tradition, the Antarctic Convergence Zone (the northern border of the Antarctic surface water). In other countries, the border is also blurred - the latitude is south of Cape Horn, the border floating ice, Antarctic Convention area (area south of 60 degrees south latitude).
This term repeatedly appeared in the 18th century, when a systematic study of the region began.
Intensive cyclonic activity is developed over the water area of the Southern Ocean. Most cyclones move from West to East. The air temperature in January off the coast of Antarctica does not exceed 0°C (–6°C in the Weddell and Ross Seas), at 50°S. rises to 7°C in the Indian and Atlantic sectors and to 12°C in the Pacific. In winter, the contrasts are even greater: in the coastal zone of the environment. the temperature drops to -20 °С (in the Weddell and Ross seas to -30 °С), and at 50 ° S.l. is 2-3 °C in the Atlantic and Indian sectors and 6-7 °C in the Pacific.
IcebergThe main feature of the Southern Ocean is the current Western winds, which spreads throughout the entire water column and carries them eastward. South of this current, the Western coastal current. Cold and dense water masses from the coast of Antarctica flow down the ocean floor far to the North. The ice cover of the Southern Ocean is more developed in the Western Hemisphere and varies greatly by season: in September - October its area is 18-19 million km², and in January - February - only 2-3 million km². The average width of the drifting ice belt in November at 30° W. is 2000 km, at 170° W. - 1500 km, at 90-150 ° E - 250-550 km.
Icebergs are constantly breaking off from the Antarctic Ice Sheet. At the same time, more than 200 thousand icebergs and their environments are located in the Southern Ocean. the length is 500 m, but there are giants up to 180 km long and several tens of kilometers wide. Icebergs are brought to the North and can be found even at 35-40°S. They exist in the ocean for an average of 6 years, but in some cases their age can exceed 12-15 years.
How deep do penguins swim?Despite the harsh climate, the Southern Ocean is rich in life. There are huge masses of phyto- and zooplankton, krill, sponges and echinoderms are abundant, several families of fish, especially notothenia. Of the birds, petrels, skuas, and penguins are numerous. There are many whales in the ocean blue whale, fin whale, sei whale, humpback whale, etc.) and seals (Weddell seal, crabeater seal, sea leopard, fur seal). Whaling is prohibited, but a lot of krill and fish are caught.
The most little-studied and, perhaps, the most interesting from the point of view of science is the Southern or Antarctic Ocean. Until 2000, the concept of the "Southern Ocean" was conditional - this is how oceanologists called the part of the world's oceans, consisting of southern parts Pacific, Atlantic and Indian Oceans and washing the coast of Antarctica.
The study of the specifics of this part of the world ocean, associated with the originality hydrological regime Antarctic waters between the convergence zone and the northern coasts of Antarctica, which are united by the circumpolar current, the uniqueness of the bottom shelf, animal and flora, as well as its special influence on the planet's climate, gave scientists reason to single out in 2000 the fifth Southern or Antarctic Ocean.
The boundary of the Southern Ocean runs along the 60th parallel of south latitude and corresponds to the northern boundary of the Antarctic convergence zone and the uniqueness of the bottom topography. Its area is 20,327 thousand square meters. km. and it is the fourth largest ocean globe. Its water part includes the Amundsen, Bellingshausen, Ross, Weddel-la seas, part of the Drake Passage, a small part of the Scottish Sea and others. bodies of water Antarctica. The relief of the Southern Ocean for the most part has a depth of 4,000 to 5,000 m with minor areas of shallow water. Its continental shelf is extremely deep, narrow and lies at depths from 400 to 800 m. The deepest point of the Antarctic Ocean is the southern tip of the Sandwich Basin - 7,235 m.
The largest ocean current in the world, which affects the formation and change of climate throughout the earth, is the Antarctic Polar Current. It moves east around Antarctica and carries 130 million cubic meters of water per second. This figure is a hundred times greater than the amount of water carried by all the rivers of the globe. The climate of the Southern Ocean is distinguished by its severity.
Fashionable direction of the 20-21 centuries - tours to Antarctica
The water temperature in the surface layers of the ocean varies from +10?C to -2?C. Due to the strong temperature contrast between the area of ice and the open ocean, cyclonic storms are almost constantly observed here, which move around Antarctica in an easterly direction. Harsh cold winds here blow much stronger than anywhere else on the planet. AT winter time The Southern Ocean freezes up to 65 degrees south in the Pacific and 55 degrees in the Atlantic, with surface temperatures well below freezing.
The Roaring Forties…
Antarctic pack ice covers an average area from a low of 2.6 million square kilometers in March to a maximum of 18.8 million square kilometers in September, increasing about sevenfold during this time. They represent a vast store of the purest fresh water on the planet. Fragments of ice shelves and continental glaciers form icebergs and floating ice. Individual Antarctic icebergs can exist for 10 or more years.
Despite the harsh climatic conditions southern ocean, living life in Antarctic waters is rich and distinctive. The waters of the southern ocean are extremely saturated with phyto- and zooplankton, represented primarily by krill. Krill is the basis of nutrition for many species of fish, cetaceans, penguins, squids, sponges, echinoderms, seals and other animals. Among the mammals that have adapted to living in such harsh conditions, it should be noted penguins, fur seals, seals. The waters of the Southern Ocean are favorite place habitats of many species of whales, such as the blue whale, fin whale, sei whale, humpback whale. extremely rich species diversity valuable breeds ocean fish, which are represented by endemic families of notothenia and white-blooded fish.
The non-vertebrate animals that live in the South Ocean waters are very peculiar. Of particular interest are huge jellyfish, reaching a weight of up to 150 kilograms. Penguins are a symbol of Antarctica and the Southern Ocean. These peculiar birds with a vertical body position are represented by 17 species. They lead a semi-terrestrial lifestyle, they feed in water. small crustaceans and fish and do not know how to fly at all like their relatives.
The Southern Ocean, due to its very harsh climate, is still little studied and represents huge interest for science and scientific discoveries. The secrets kept in the waters of the Southern Ocean will amaze humanity with their discoveries and sensations more than once.
The Southern Ocean is considered the youngest on the planet. It is located in the Southern Hemisphere and is adjacent to other oceans. The waters of the Southern Ocean wash only one continent - Antarctica.
History of the discovery of the Southern Ocean
Interest in the Southern Ocean arose a very long time ago. For the first time, they tried to explore it in the 18th century, but travelers were stopped by large-scale accumulations of ice - the technology of that time did not allow to overcome this obstacle. But it appeared on the map even earlier, in 1650.
English and Norwegian whalers visited polar Antarctica in the 19th century, and in the 20th century, the Southern Ocean became the site of whaling and scientific research. The International Geographical Organization singled out the Southern Ocean in 2000, uniting the waters of the southern regions of the Atlantic, Pacific and Indian oceans into one. And although the Southern Ocean has only conditional boundaries (this is due to the fact that there are no islands and continents in its southern part), its existence has long been proven, although the decision of the hydrological organization has not been legalized.
Characteristics of the Southern Ocean
The Southern Ocean covers an area of more than 20 million square kilometers. m. In the south it borders on the coast of the southern polar continent, in the west and east it has no clearly defined boundaries. Most deep place ocean - the South Sandwich Trench (Meteor depression). His maximum depth is 8428 m, and the average is 3503 m. Near the coast of Antarctica, 14 marginal seas are distinguished, which are part of the ocean: Somov, Durville, Mawson, Commonwealth, Cosmonauts, King Haakon VII, Riiser-Larsen, Lazarev, Davis, Amundsen, Ross, Bellingshausen, Skosh and Weddell.
The main feature of the Southern Ocean is the change in its conditional geographical boundaries in time and space due to interseasonal and interannual changes in the position of the Antarctic convergence lines. Another feature of the ocean area is a large number of icebergs (scientists record more than 200 thousand annually).
Climate of the Southern Ocean
The coast of the Southern Ocean is an area where harsh elements reign. Above the water, a predominantly maritime climate is observed, while on the coast it is closer to the Antarctic. Throughout the year it is cloudy, windy and cold. Snow falls in any season.
Closer to the Arctic Circle, the most powerful winds on the planet are formed. Big difference temperatures contributes to frequent storms. In winter, the air temperature can drop to 65 degrees below zero. Scientists classify the atmosphere over the Southern Ocean as environmentally friendly.
Such weather conditions are due to a number of factors: the close location of Antarctica, the lack of warm currents, the permanent presence of ice cover. A zone is constantly formed over land high blood pressure, and around it is a zone reduced pressure.
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The youngest ocean on the planet is the South or Antarctic. It is located in the Southern Hemisphere, has points of contact with other oceans, excluding northern ocean. The waters of the Southern Ocean wash Antarctica. The International Geographical Organization identified it in 2000, uniting the waters of the southern regions of the Indian, Pacific and Atlantic Oceans. This ocean has conditional boundaries, since there are no continents and islands in the northern part of its water area.
Discovery history
The Southern Ocean has been an object of human interest for a very long time. They tried to explore it back in the 18th century, but at that time the ice shell was an insurmountable obstacle for travelers. It appeared on the map even earlier, in 1650. In the 19th century, whalers from England and Norway managed to visit polar Antarctica. In the 20th century, the Southern Ocean was a whaling area and a site for scientific research.
The existence of the Southern Ocean is now a proven fact, but this decision hydrological organization is not legalized. Thus, legally there is no such area on the planet. At the same time, the Southern Ocean is marked on the world map. The southern border of its water area is Antarctica, the northern border is considered to be 60 degrees south latitude.
Geographic details
The ocean occupies more than 20 million square meters. km. The South Sandwich Trench is the deepest place in the ocean, where the maximum elevation reaches 8428 m. A map of the Southern Ocean shows that it was formed next seas: Commonwealth, Mawson, Ross, Durvel, Somov, Skosh, Lazarev, Cosmonauts, Riiser-Larsen, Amundsen, Weddell, Davis and Bellingshausen. There are many islands of different sizes in the water area. Almost all of them are of volcanic origin. The largest islands include South Shetland, South Orkney, Kerguelen.
Climatic features
The coast of the Southern Ocean is an area dominated by harsh elements. Conditions prevail over water maritime climate, and on the coast there is an Antarctic climate. All year round It's cold, windy and overcast here. Snow falls in any season.
Closer to the Arctic Circle, the most powerful winds on the planet are formed. Storms are formed due to the huge temperature difference between the waters of the ocean and the air. In winter, the air reaches 60-65 degrees below zero. The atmosphere above the water area is characterized by ecological cleanliness.
Weather due to a number of reasons: the proximity of Antarctica, the permanent ice cover, the absence of warm sea currents. A zone of high pressure constantly forms over land. At the same time, an area of low pressure, or the Antarctic depression, is forming around Antarctica. A feature of the water area is a large number of icebergs, which are formed as a result of breaking off parts of glaciers under the influence of tsunamis, swells and waves. There are more than 200,000 icebergs annually in the Southern Ocean.
And often distinguished as the "fifth ocean", which, however, does not have a northern border clearly defined by islands and continents. The area of the Southern Ocean can be determined by an oceanological feature: as a line of convergence of cold Antarctic currents with warmer ones. waters of three oceans. But such a border constantly changes its position and depends on the season, so it is inconvenient for practical purposes. In 2000, the member states of the International Hydrographic Organization decided to single out the Southern Ocean as an independent fifth ocean, uniting the southern parts of the Atlantic, Indian and Pacific Oceans, within the limits limited from the north by the 60th parallel of south latitude, and also limited by the Antarctic Treaty. The accepted area of the Southern Ocean is 20.327 million km² (between the coast of Antarctica and the 60th parallel of south latitude).
The greatest depth of the ocean lies in the South Sandwich Trench and is 8264 m. The average depth is 3270 m. The length of the coastline is 17,968 km.
As of 1978, in all Russian-language practical maritime manuals (nautical navigation charts, sailing directions, lights and signs, etc.), the concept of "Southern Ocean" was absent, the term was not used among sailors.
Since the end of the 20th century, the Southern Ocean has been signed on maps and in atlases published by Roskartografiya. In particular, it is signed in the 3rd edition of the fundamental Atlas of the World and in other atlases published already in the 21st century.
Seas around Antarctica
Usually, 13 seas are distinguished off the coast of Antarctica: Weddell, Scotia, Bellingshausen, Ross, Amundsen, Davis, Lazarev, Riiser-Larsen, Cosmonauts, Commonwealth, Mawson, D'Urville, Somov; in Norway, it is also customary to single out the Sea of King Haakon VII. The most important islands of the Southern Ocean: Kerguelen, South Shetland, South Orkney. The Antarctic shelf is submerged to a depth of 500 meters.
All the seas washing Antarctica, except for the Scotia and Weddell Seas, are marginal. In the tradition accepted in most countries, they divide its coast into sectors as follows:
| Name | Sector | In whose honor is it named | |||
|---|---|---|---|---|---|
| . | |||||
| Sea of Lazarev | 0-14° in. d. | Mikhail Lazarev | |||
| Riiser-Larsen Sea | 14-34° in. d. | Hjalmar Riiser-Larsen, major general, creator of the Norwegian Air Force | |||
| Sea of Cosmonauts | 34-45° in. d. | First cosmonauts (1961-1962) | |||
| Commonwealth Sea | 70-87° in. d. | The international cooperation in Antarctica | |||
| Davis Sea | 87-98° in. d. | J. K. Davies, Captain of the Aurora, Mawson Expedition (1911-14) | |||
| Mawson Sea | 98-113° in. d. | Douglas Mawson, geologist, leader of three expeditions | |||
| Sea of D'Urville | 136-148° in. d. | Jules Dumont-Durville, oceanographer, rear admiral | |||
| Sea of Somov | 148-170° in. d. | Mikhail Somov, head of the first Soviet expedition (1955-57) | |||
| Ross Sea | 170° in. - 158°W d. | James Ross, Rear Admiral, first crossed 78°S sh. | |||
| Amundsen Sea | 100-123°W d. | Roald Amundsen, first to reach the south pole | |||
| Bellingshausen Sea | 70-100°W d. | Thaddeus Bellingshausen, admiral, discoverer of Antarctica | |||
| sea scotia | 30-50°W 55-60°S sh. | "Scotia" (eng. Scotia), ship of the Bruce expedition (1902-1904) | |||
| Weddell Sea | 10-60°W d., 78-60°S sh. | James Weddell, whaler who explored the region in the 1820s | |||
| Sea of King Haakon VII (rarely used) | 20° in. 67°S sh. | Haakon VII, King of Norway | |||
| . | |||||
Southern Ocean in cartography
Many maps of Australia refer to the "Southern Ocean" as the sea immediately south of Australia.
The Southern Ocean was first identified in 1650 by the Dutch geographer Bernhard Varenius and included as yet undiscovered by Europeans " southern mainland”, and all areas above the Antarctic Circle.
At present, the ocean itself continues to be considered a water mass, which is mostly surrounded by land. In 2000, the International Hydrographic Organization adopted a five-ocean division, but this decision has never been ratified. The current 1953 definition of the oceans does not include the Southern Ocean.
In the Soviet tradition (1969), the approximate boundary of the conditional "Southern Ocean" was considered to be the northern boundary of the Antarctic Convergence Zone, located near 55 ° south latitude. In other countries, the border is also blurred - the latitude south of Cape Horn, the border of floating ice, the Antarctic Convention zone (the area south of 60 parallel south latitude). The Australian Government considers the "Southern Ocean" to be the waters immediately south of the Australian continent.
in atlases and geographic Maps the name "Southern Ocean" was included until the first quarter of the 20th century. AT Soviet time this term was not used ], however, since the end of the 20th century, he began to sign on maps published by Roskartografiya.
History of Southern Ocean exploration
XVI-XIX centuries
The first ship to cross the border of the Southern Ocean belonged to the Dutch; it was commanded by Dirk Geeritz, who sailed in the squadron of Jacob Magyu. In 1559, in the Strait of Magellan, the ship Geeritz, after a storm, lost sight of the squadron and went south. Having descended to 64 ° south latitude, it saw high ground- Possibly South Orkney. In 1671, Anthony de la Roche discovered South Georgia; in 1739 Bouvet Island was discovered; in 1772 French Marine officer Kerguelen discovered an island in the Indian Ocean named after him.
Almost simultaneously with the voyage of Kerguelen from England, he set off on his first trip to Southern Hemisphere James Cook, and already in January 1773, his ships Adventure and Resolution crossed the Antarctic Circle at the meridian 37 ° 33 "E. After a hard struggle with ice, he reached 67 ° 15" south latitude, where he was forced to turn north. In December of the same year, Cook again went to the Southern Ocean, on December 8 he crossed the Antarctic Circle at 150 ° 6 "West longitude and at the parallel of 67 ° 5" S. latitude was covered with ice, freed from which, went further south and, in late January 1774, reached 71°15" south latitude, at 109°14" west longitude, southwest of Tierra del Fuego. Here an impenetrable wall of ice prevented him from going further. On his second voyage in the Southern Ocean, Cook crossed the Antarctic Circle twice. During both voyages, he became convinced that the abundance ice mountains indicates the existence of a significant Antarctic continent. The difficulties of polar navigation were described by him in such a way that only whalers continued to visit these latitudes and the southern polar scientific expeditions ceased for a long time.
In 1819, the Russian navigator Bellingshausen, commanding the warships Vostok and Mirny, visited South Georgia and tried to penetrate deep into the Southern Ocean; for the first time, in January 1820, almost on the Greenwich meridian, he reached 69 ° 21 "south latitude; then, having gone beyond the limits of the southern polar circle, Bellingshausen passed along it to the east to 19 ° east longitude, where he crossed it again and reached in February again almost the same latitude (69°6"). Further east, it rose only to 62 ° parallel and continued its journey along the margin of the floating ice, then, on the meridian of the Balleny Islands, it reached 64 ° 55 ", in December 1820, at 161 ° west longitude, passed the southern polar circle and reached 67 ° 15 "south latitude, and in January 1821, between the meridians 99 ° and 92 ° west longitude, reached 69 ° 53" south latitude; then, almost on the meridian 81 °, opened in 68 ° 40 "south latitude, a high coast islands of Peter I, and passing even to the east, inside the southern polar circle - the coast of Alexander I Land. Thus, Bellingshausen was the first to make a full voyage around the South Arctic continent, discovered by him, almost all the time between latitudes 60 ° - 70 °, on small sailing ships.
steam ship L'Astrolabe in 1838
At the end of 1837, a French expedition, under the command of Dumont-Durville, consisting of two steam ships - the Astrolabe (L'Astrolabe) and the Zele (La Zélée), set off to explore Oceania, to verify information Veddel and others. In January 1838, Dumont-D'Urville took the path of Weddel, but ice blocked his path at the parallel of 63 ° south latitude. South of the South Shetland Islands, he saw a high coast called Louis Philippe Land; later it turned out that this land is an island, the western shores of which are called Trinity Land and Palmer Land. After wintering in Tasmania, on the way to the south, Dumont-D'Urville met the first ice and after a difficult navigation between them, on January 9, 1840, in latitudes 66 ° - 67 °, almost on the Arctic Circle, and 141 ° E. D. saw a high mountainous coast. This land, called Land Adélie, Dumont-D'Urville traced along the Arctic Circle to the meridian 134 ° east longitude On January 17, at 65 ° south latitude and 131 ° east longitude, another coast was discovered, called the Clary Coast.
An American expedition, consisting of three ships: "Vincennes", "Peacock" and "Porpoise", under the command of Lieutenant Willis, set out from the Tierra del Fuego archipelago in February 1839 in order to try to pass the Weddel route to the south, but she was met with the same insurmountable obstacles , like Dumont-Durville, and she was forced to return without any special results to Chile (on the meridian of 103 ° west longitude, she reached almost 70 ° south latitude and then, as if, she saw the earth). In January 1840, the American explorer Charles Wilkes went almost due south along longitude 160° east. Already at the parallel of 64 ° 11 "S, the ice blocked his further path. Turning to the west and reaching the meridian 153 ° 6" East longitude, at 66 ° South latitude, he saw a mountain 120 km away, which was named by Ringold Knoll. Ross, who visited these places a little later, disputed Wilkes' discovery, but without foundation. Opening honor various parts The land of Wilkes actually belongs to each of the three navigators - Wilkes, Dumont-Durville and Ross - separately. During January and February 1840, Wilkes traveled a considerable distance along the margins of the Antarctic continent and reached the meridian 96° East. For all the time of the voyage, he did not manage to land on the shore anywhere.
A third English expedition, under the command of James Clark Ross, on the steam ships Erebus (Erebus) and Terror (Erebus commander was Crozier), was equipped to explore the south polar countries in general. In August 1840, Ross was in Tasmania, where he learned that Dumont-D'Urville had just discovered the coast of Adélie's Land; this prompted him to begin his explorations further east, on the meridian of the Balleny Islands. In December 1840, the expedition crossed the Antarctic Circle on the meridian 169 ° 40 "E. and soon began to struggle with ice. After 10 days, the ice strip was passed, and on December 31 (old style) they saw the high coast of Victoria Land, one of the highest mountain peaks which Ross named after the initiator of the expedition - Sabina, and the entire chain of mountains with a height of 2000 - 3000 m - the Admiralty ridge. All the valleys of this chain were littered with snow and huge glaciers descending to the sea. Behind Cape Adar, the coast turned south, remaining mountainous and impregnable Ross landed on one of the Possession Islands, at 71 ° 56 "south latitude and 171 ° 7" east longitude, completely devoid of vegetation and inhabited by a mass of penguins that covered its shores with a thick layer of guano. Continuing his navigation further south, Ross discovered the Kuhlman Islands and Franklin (the latter - at 76 ° 8 "south latitude) and saw the coast directly to the south and high mountain(Erebus volcano) with a height of 3794 meters, and a little to the east another volcano was seen, already extinct, called Terror, 3230 meters high. The further way to the south was blocked by the coast, turning to the east and bordered by a continuous vertical ice wall, up to 60 meters high above the water, which, according to Ross, descends to a depth of about 300 meters. This ice barrier was distinguished by the absence of any significant depressions, bays or capes; its nearly level, vertical wall stretched for a vast distance. Beyond the ice shore to the south were the peaks of a high mountain range, which went deep into the southern polar continent; it is named after Parry. Ross passed from Victoria Land to the east for about 840 km, and throughout this length the character of the ice coast remained unchanged. Finally, the late season forced Ross to return to Tasmania. On this voyage, he reached 78 ° 4 "south latitude, between meridians 173 ° -174 ° west longitude. On the second voyage, his ships crossed the Antarctic Circle again on December 20, 1841 and went south. In early February 1842, on meridian 165 ° west, they reached a more open sea and headed directly south, approaching the ice coast a little more east than in 1841. At 161 ° 27 "W they reached 78 ° 9" S, that is, they approached south pole closer than anyone so far. Further navigation to the east was blocked solid ice(pak), and the expedition turned to the north. In December 1842, Ross made a third attempt to penetrate south; this time he chose the path of Weddel and headed for the Land of Louis-Philippe. Going east, Ross crossed the Arctic Circle on meridian 8° west and on February 21 reached 71°30" south latitude, 14°51 west longitude.
Almost 30 years later, an expedition on the Challenger corvette visited, among other things, the southern polar countries. Having visited Kerguelen Island, the Challenger headed south and reached 65° 42 "S. should have been at a distance of only 30 kilometers, it was not visible.
Climate and weather
Sea temperatures vary from about −2 to 10 °C. The cyclonic movement of storms is eastward around the continent and often becomes intense due to the temperature contrast between the ice and the open ocean. The ocean region from 40 degrees south latitude to the Antarctic Circle has the strongest average winds on Earth. In winter, the ocean freezes to 65 degrees south latitude in the Pacific sector and 55 degrees south latitude in the Atlantic sector, dropping surface temperatures well below 0 °C; at some coastal points permanent strong winds leave the coastline ice-free during the winter.
Icebergs can be found at any time of the year throughout the Southern Ocean. Some of them are capable of reaching several hundred meters; smaller icebergs, iceberg fragments and sea ice (typically 0.5 to 1 meter) also pose problems for ships. The icebergs encountered are 6-15 years old, which implies the simultaneous existence of more than 200,000 icebergs in the waters of the ocean, ranging in length from 500 meters to 180 km and a width of up to several tens of kilometers.