Misplaced Pages

#278721

109-537: Main five oceans division: Further subdivision: The Arctic Ocean is the smallest and shallowest of the world's five oceanic divisions . It spans an area of approximately 14,060,000 km (5,430,000 sq mi) and is the coldest of the world's oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, although some oceanographers call it the Arctic Mediterranean Sea . It has also been described as an estuary of

218-533: A German liner, rammed an iceberg and suffered a crushed bow, but she was still able to complete her voyage. The advent of watertight compartmentalization in ship construction led designers to declare their ships "unsinkable". During the 1912 sinking of the Titanic , the iceberg that sank the Titanic killed more than 1,500 of its estimated 2,224 passengers and crew, seriously damaging the 'unsinkable' claim. For

327-430: A fizzing sound that some may call "Bergie Seltzer ". This sound results when the water-ice interface reaches compressed air bubbles trapped in the ice. As each bubble bursts it makes a "popping" sound and the acoustic properties of these bubbles can be used to study iceberg melt. An iceberg may flip, or capsize, as it melts and breaks apart, changing the center of gravity . Capsizing can occur shortly after calving when

436-658: A line to Cape Morris Jesup ( Greenland ). Note that these definitions exclude any marginal waterbodies that are separately defined by the IHO (such as the Kara Sea and East Siberian Sea ), though these are usually considered to be part of the Arctic Ocean. The CIA defines the limits of the Arctic Ocean differently, as depicted in the map comparing its definition to the IHO's definition. The Atlantic Ocean separates

545-628: A pressure system that drives the anticyclonic motion of the Beaufort Gyre. During the summer, this area of high pressure is pushed out closer to its Siberian and Canadian sides. In addition, there is a sea level pressure (SLP) ridge over Greenland that drives strong northerly winds through the Fram Strait, facilitating ice export. In the summer, the SLP contrast is smaller, producing weaker winds. A final example of seasonal pressure system movement

654-420: A warming of approximately 5–8 °C (9–14 °F), the region reached an average annual temperature of 10–20 °C (50–68 °F). The surface waters of the northernmost Arctic Ocean warmed, seasonally at least, enough to support tropical lifeforms (the dinoflagellates Apectodinium augustum ) requiring surface temperatures of over 22 °C (72 °F). Borders of the oceans The borders of

763-421: Is a constant based on properties of the iceberg and the ocean and is approximately 0.75 ∘ C − 1 m 0.4 day − 1 s 0.8 {\displaystyle 0.75^{\circ }{\text{C}}^{-1}{\text{m}}^{0.4}{\text{day}}^{-1}{\text{s}}^{0.8}} in the polar ocean. The influence of the shape of an iceberg and of

872-588: Is a key driver in Arctic Ocean circulation and the formation of water masses. With this dependence, the Arctic Ocean experiences variations due to seasonal changes in sea ice cover. Sea ice movement is the result of wind forcing, which is related to a number of meteorological conditions that the Arctic experiences throughout the year. For example, the Beaufort High—an extension of the Siberian High system—is

981-733: Is a water mass referred to as Atlantic Water. Inflow from the North Atlantic Current enters through the Fram Strait, cooling and sinking to form the deepest layer of the halocline, where it circles the Arctic Basin counter-clockwise. This is the highest volumetric inflow to the Arctic Ocean, equalling about 10 times that of the Pacific inflow, and it creates the Arctic Ocean Boundary Current. It flows slowly, at about 0.02 m/s. Atlantic Water has

1090-488: Is also poorly understand and may extend into the Laptev Sea. In large parts of the Arctic Ocean, the top layer (about 50 m [160 ft]) is of lower salinity and lower temperature than the rest. It remains relatively stable because the salinity effect on density is bigger than the temperature effect. It is fed by the freshwater input of the big Siberian and Canadian rivers ( Ob , Yenisei , Lena , Mackenzie ),

1199-486: Is an area of oceanic crust covered by water. See also: List of seas on Earth for the seas included in each oceanic area. Though generally described as several separate oceans, the world's oceanic waters constitute one global, interconnected body of salt water sometimes referred to as the World Ocean or Global Ocean. This concept of a continuous body of water with relatively free interchange among its parts

SECTION 10

#1732766286279

1308-626: Is an area of oceanic crust covered by water. Oceanic crust is the thin layer of solidified volcanic basalt that covers the Earth's mantle . Continental crust is thicker but less dense. From this perspective, the Earth has three oceans: the World Ocean, the Caspian Sea , and the Black Sea . The latter two were formed by the collision of Cimmeria with Laurasia . The Mediterranean Sea

1417-743: Is at times a discrete ocean because tectonic plate movement has repeatedly broken its connection to the World Ocean through the Strait of Gibraltar . The Black Sea is connected to the Mediterranean through the Bosporus , but the Bosporus is a natural canal cut through continental rock some 7,000 years ago, rather than a piece of oceanic sea floor like the Strait of Gibraltar. Despite their names, some smaller landlocked "seas" are not connected with

1526-492: Is called Arctic Bottom Water and begins around 900 m (3,000 ft) depth. It is composed of the densest water in the World Ocean and has two main sources: Arctic shelf water and Greenland Sea Deep Water. Water in the shelf region that begins as inflow from the Pacific passes through the narrow Bering Strait at an average rate of 0.8 Sverdrups and reaches the Chukchi Sea . During the winter, cold Alaskan winds blow over

1635-415: Is cloudy year-round, with mean cloud cover ranging from 60% in winter to over 80% in summer. The temperature of the surface water of the Arctic Ocean is fairly constant at approximately −1.8 °C (28.8 °F), near the freezing point of seawater . The density of sea water, in contrast to fresh water, increases as it nears the freezing point and thus it tends to sink. It is generally necessary that

1744-709: Is connected to the Pacific by the Bering Strait , forming a continuous expanse of water. The five oceans are: The Arctic Ocean covers much of the Arctic and washes upon Northern America and Eurasia . It is sometimes considered a sea or estuary of the Atlantic Ocean. The International Hydrographic Organization (IHO) defines the limits of the Arctic Ocean (excluding the seas it contains) as follows: Between Greenland and West Spitzbergen [ sic ] – The Northern limit of Greenland Sea . Between West Spitzbergen and North East Land –

1853-562: Is contained in a polar climate characterized by persistent cold and relatively narrow annual temperature ranges. Winters are characterized by the polar night , extreme cold, frequent low-level temperature inversions, and stable weather conditions. Cyclones are only common on the Atlantic side. Summers are characterized by continuous daylight ( midnight sun ), and air temperatures can rise slightly above 0 °C (32 °F). Cyclones are more frequent in summer and may bring rain or snow. It

1962-804: Is frequently used, some geographic authorities such as the 10th edition of the World Atlas from the U.S. National Geographic Society generally show the Atlantic, Indian, and Pacific Oceans continuing to Antarctica. If and when adopted, the 2002 definition would be published in the 4th edition of Limits of Oceans and Seas , re-instituting the 2nd edition's "Southern Ocean", omitted from the 3rd edition. Iceberg Icebergs vary considerably in size and shape. Icebergs that calve from glaciers in Greenland are often irregularly shaped while Antarctic ice shelves often produce large tabular (table top) icebergs. The largest iceberg in recent history, named B-15 ,

2071-527: Is made from icebergs found around St. John's, Newfoundland . Although annual iceberg supply in Newfoundland and Labrador exceeds the total freshwater consumption of the United States, in 2016 the province introduced a tax on iceberg harvesting and imposed a limit on how much fresh water can be exported yearly. The freshwater injected into the ocean by melting icebergs can change the density of

2180-484: Is now Prudhoe Bay. At the same time, sediments shed off the rising Canadian Rockies built out the large Mackenzie Delta. The rifting apart of the supercontinent Pangea , beginning in the Triassic period, opened the early Atlantic Ocean. Rifting then extended northward, opening the Arctic Ocean as mafic oceanic crust material erupted out of a branch of Mid-Atlantic Ridge. The Amerasia Basin may have opened first, with

2289-446: Is of fundamental importance to oceanography . The major oceanic divisions are defined in part by the continents , various archipelagos , and other criteria. The principal divisions (in descending order of area) are the: Pacific Ocean , Atlantic Ocean , Indian Ocean , Southern (Antarctic) Ocean , and Arctic Ocean . Smaller regions of the oceans are called seas , gulfs , bays , straits , and other terms. Geologically, an ocean

SECTION 20

#1732766286279

2398-490: Is the iceberg that sank the Titanic . The catastrophe led to the establishment of an International Ice Patrol shortly after. Icebergs in both the northern and southern hemispheres have often been compared in size to multiples of the 59.1 square kilometres (22.8 sq mi)-area of Manhattan Island . Artists have used icebergs as the subject matter for their paintings. Frederic Edwin Church , The Icebergs , 1861

2507-573: Is the low pressure system that exists over the Nordic and Barents Seas. It is an extension of the Icelandic Low , which creates cyclonic ocean circulation in this area. The low shifts to centre over the North Pole in the summer. These variations in the Arctic all contribute to ice drift reaching its weakest point during the summer months. There is also evidence that the drift is associated with

2616-418: Is the melt rate in m/day, Δ u {\displaystyle \Delta u} is the relative velocity between the iceberg and the ocean, T 0 − T {\displaystyle T_{0}-T} is the temperature difference between the ocean and the iceberg, and L {\displaystyle L} is the length of the iceberg. K {\displaystyle K}

2725-665: The Amerasian Basin (sometimes called the North American or Hyperborean Basin), which is about 4,000 m (13,000 ft) deep. The bathymetry of the ocean bottom is marked by fault block ridges, abyssal plains , ocean deeps , and basins. The average depth of the Arctic Ocean is 1,038 m (3,406 ft). The deepest point is Molloy Hole in the Fram Strait , at about 5,550 m (18,210 ft). The two major basins are further subdivided by ridges into

2834-880: The Antarctic Continent ; a line from Cape Virgins ( 52°21′S 68°21′W  /  52.350°S 68.350°W  / -52.350; -68.350 ) to Cape Espiritu Santo , Tierra del Fuego, the Eastern entrance to Magellan Strait . On the West. The limit of the Rio de La Plata . On the North. The Southern limit of the North Atlantic Ocean. On the Northeast. The limit of the Gulf of Guinea . On

2943-739: The Atlantic Ocean . It is also seen as the northernmost part of the all-encompassing world ocean . The Arctic Ocean includes the North Pole region in the middle of the Northern Hemisphere and extends south to about 60°N . The Arctic Ocean is surrounded by Eurasia and North America, and the borders follow topographic features: the Bering Strait on the Pacific side and the Greenland Scotland Ridge on

3052-714: The Canada Basin (between Beaufort Shelf of North America and the Alpha Ridge ), Makarov Basin (between the Alpha and Lomonosov Ridges), Amundsen Basin (between Lomonosov and Gakkel ridges), and Nansen Basin (between the Gakkel Ridge and the continental shelf that includes the Franz Josef Land ). The crystalline basement rocks of mountains around the Arctic Ocean were recrystallized or formed during

3161-746: The Chukchi Borderland moved along to the northeast by transform faults. Additional spreading helped to create the "triple-junction" of the Alpha-Mendeleev Ridge in the Late Cretaceous epoch . Throughout the Cenozoic Era, the subduction of the Pacific plate, the collision of India with Eurasia, and the continued opening of the North Atlantic created new hydrocarbon traps. The seafloor began spreading from

3270-514: The Dutch word ijsberg , literally meaning ice mountain , cognate to Danish isbjerg , German Eisberg , Low Saxon Iesbarg and Swedish isberg . Typically about one-tenth of the volume of an iceberg is above water, which follows from Archimedes's Principle of buoyancy ; the density of pure ice is about 920  kg/m (57 lb/cu ft), and that of seawater about 1,025 kg/m (64 lb/cu ft). The contour of

3379-490: The Grand Banks of Newfoundland and provided the "limits of all known ice" in that vicinity to the maritime community. The IIP published their first records in 1921, which allowed for a year-by-year comparison of iceberg movement. Aerial surveillance of the seas in the early 1930s allowed for the development of charter systems that could accurately detail the ocean currents and iceberg locations. In 1945, experiments tested

Arctic Ocean - Misplaced Pages Continue

3488-543: The Gulf of Alaska and Coral Sea ), though these are usually considered to be part of the Pacific Ocean. In its 2002 draft, the IHO redefined the Pacific Ocean, moving its southern limit to 60°S, with the waters south of that line identified as the Southern Ocean . This new definition has not yet been ratified (and, in addition, a reservation was lodged in 2003 by Australia.) While the name "Southern Ocean"

3597-531: The Independence I and Independence II cultures of northeastern Canada and Greenland ( c.  2400–1800 BC and c.  800–1 BC ); and the Groswater of Labrador and Nunavik . The Dorset culture spread across Arctic North America between 500 BC and AD 1500. The Dorset were the last major Paleo-Eskimo culture in the Arctic before the migration east from present-day Alaska of

3706-670: The Northwest Passage , to " Cathay " ( China ) caused water to win out, and by 1723 mapmakers such as Johann Homann featured an extensive "Oceanus Septentrionalis" at the northern edge of their charts. The few expeditions to penetrate much beyond the Arctic Circle in that era added only small islands, such as Novaya Zemlya (11th century) and Spitzbergen (1596), though, since these were often surrounded by pack-ice , their northern limits were not so clear. The makers of navigational charts , more conservative than some of

3815-1244: The Shetland Islands . On the East. The Northwestern limit of the North Sea , the Northern and Western limits of the Scottish Seas , the Southern limit of the Irish Sea , the Western limits of the Bristol and English Channels , of the Bay of Biscay and of the Mediterranean Sea . On the South. The equator , from the coast of Brazil to the Southwestern limit of the Gulf of Guinea . Note that this definition excludes any marginal waterbodies that are separately defined by

3924-407: The Southern Ocean . This new definition has not yet been ratified (and, in addition, a reservation was lodged in 2003 by Australia.) While the name "Southern Ocean" is frequently used, some geographic authorities such as the 10th edition of the World Atlas from the U.S. National Geographic Society generally show the Atlantic, Indian, and Pacific Oceans continuing to Antarctica. If and when adopted,

4033-641: The Thule people , ancestors of the modern Inuit . The Thule Tradition lasted from about 200 BC to AD 1600, arising around the Bering Strait and later encompassing almost the entire Arctic region of North America. The Thule people were the ancestors of the Inuit, who now live in Alaska, Northwest Territories , Nunavut , Nunavik (northern Quebec), Labrador and Greenland. For much of European history ,

4142-558: The synthetic aperture radar (SAR) on the Sentinel-1 satellites . In Labrador and Newfoundland, iceberg management plans have been developed to protect offshore installations from impacts with icebergs. The idea of towing large icebergs to other regions as a source of water has been raised since at least the 1950s, without having been put into practice. In 2017, a business from the UAE announced plans to tow an iceberg from Antarctica to

4251-699: The "Southern Ocean". This definition was carried through to Australian constitutional law upon the Federation of Australia in 1901. The Pacific is the ocean that separates Asia and Australia from the Americas . It may be further subdivided by the Equator into northern and southern portions. The 3rd edition, currently in force, of the International Hydrographic Organization 's (IHO) Limits of Oceans and Seas defines

4360-471: The 'perfect storm' conditions of the Great Arctic Cyclone of 2012 . Waters originating in the Pacific and Atlantic both exit through the Fram Strait between Greenland and Svalbard Island, which is about 2,700 m (8,900 ft) deep and 350 km (220 mi) wide. This outflow is about 9 Sv. The width of the Fram Strait is what allows for both inflow and outflow on the Atlantic side of

4469-587: The 1980s, drifting buoys were used in Antarctic waters for oceanographic and climate research . They are equipped with sensors that measure ocean temperature and currents. Side looking airborne radar (SLAR) made it possible to acquire images regardless of weather conditions. On November 4, 1995, Canada launched RADARSAT-1 . Developed by the Canadian Space Agency , it provides images of Earth for scientific and commercial purposes. This system

Arctic Ocean - Misplaced Pages Continue

4578-413: The 2002 definition would be published in the 4th edition of Limits of Oceans and Seas , re-instituting the 2nd edition's "Southern Ocean", omitted from the 3rd edition. The boundary of the Indian Ocean is a constitutional issue for Australia. The Imperial South Australia Colonisation Act, 1834 , which established and defined the Colony of South Australia defined South Australia's southern limit as being

4687-401: The Americas from Europe and Africa . It may be further subdivided by the Equator into northern and southern portions. The 3rd edition, currently in force, of the International Hydrographic Organization 's (IHO) Limits of Oceans and Seas defines the limits of the North Atlantic Ocean (excluding the seas it contains) as follows: On the West. The Eastern limits of the Caribbean Sea ,

4796-406: The Arctic Ocean. Because of this, it is influenced by the Coriolis force , which concentrates outflow to the East Greenland Current on the western side and inflow to the Norwegian Current on the eastern side. Pacific water also exits along the west coast of Greenland and the Hudson Strait (1–2 Sv), providing nutrients to the Canadian Archipelago. As noted, the process of ice formation and movement

4905-403: The Arctic Ocean. Much of the Arctic ice pack is also covered in snow for about 10 months of the year. The maximum snow cover is in March or April—about 20–50 cm (7.9–19.7 in) over the frozen ocean. The climate of the Arctic region has varied significantly during the Earth's history. During the Paleocene–Eocene Thermal Maximum 55 million years ago, when the global climate underwent

5014-435: The Arctic Ocean: Different authorities put various marginal seas in either the Arctic Ocean or the Atlantic Ocean, including: Hudson Bay , Baffin Bay , the Norwegian Sea , and Hudson Strait . The main islands and archipelagos in the Arctic Ocean are, from the prime meridian west: There are several ports and harbours on the Arctic Ocean. The ocean's Arctic shelf comprises a number of continental shelves , including

5123-422: The Atlantic Ocean, moving its southern limit to 60°S, with the waters south of that line identified as the Southern Ocean . This new definition has not yet been ratified (and, in addition, a reservation was lodged in 2003 by Australia.) While the name "Southern Ocean" is frequently used, some geographic authorities such as the 10th edition of the World Atlas from the U.S. National Geographic Society generally show

5232-472: The Atlantic side. It is mostly covered by sea ice throughout the year and almost completely in winter . The Arctic Ocean's surface temperature and salinity vary seasonally as the ice cover melts and freezes; its salinity is the lowest on average of the five major oceans, due to low evaporation , heavy fresh water inflow from rivers and streams, and limited connection and outflow to surrounding oceanic waters with higher salinities. The summer shrinking of

5341-478: The Atlantic, Indian, and Pacific Oceans continuing to Antarctica. If and when adopted, the 2002 definition would be published in the 4th edition of Limits of Oceans and Seas , re-instituting the 2nd edition's "Southern Ocean", omitted from the 3rd edition. The Indian Ocean washes upon southern Asia and separates Africa and Australia . The 3rd edition, currently in force, of the International Hydrographic Organization 's (IHO) Limits of Oceans and Seas defines

5450-448: The Canadian Arctic shelf, underlying the Canadian Arctic Archipelago , and the Russian continental shelf , which is sometimes called the "Arctic Shelf" because it is larger. The Russian continental shelf consists of three separate, smaller shelves: the Barents Shelf, Chukchi Sea Shelf and Siberian Shelf . Of these three, the Siberian Shelf is the largest such shelf in the world; it holds large oil and gas reserves. The Chukchi shelf forms

5559-418: The Chukchi Sea due to inflow from large Canadian and Siberian rivers. The final defined water mass in the Arctic Ocean is called Arctic Surface Water and is found in the depth range of 150–200 m (490–660 ft). The most important feature of this water mass is a section referred to as the sub-surface layer. It is a product of Atlantic water that enters through canyons and is subjected to intense mixing on

SECTION 50

#1732766286279

5668-427: The Chukchi Sea, freezing the surface water and pushing this newly formed ice out to the Pacific. The speed of the ice drift is roughly 1–4 cm/s. This process leaves dense, salty waters in the sea that sink over the continental shelf into the western Arctic Ocean and create a halocline. This water is met by Greenland Sea Deep Water, which forms during the passage of winter storms. As temperatures cool dramatically in

5777-497: The Coriolis force on iceberg melting rates has been demonstrated in laboratory experiments. Wave erosion is more poorly constrained but can be estimated by where M e {\displaystyle M_{\text{e}}} is the wave erosion rate in m/day, c = 1 12 m day − 1 {\displaystyle c={\frac {1}{12}}{\text{m day}}^{-1}} , S S {\displaystyle S_{\text{S}}} describes

5886-409: The Earth. The NIC is the only organization that names and tracks all Antarctic Icebergs. It assigns each iceberg larger than 10 nautical miles (19 km) along at least one axis a name composed of a letter indicating its point of origin and a running number. The letters used are as follows: The Danish Meteorological Institute monitors iceberg populations around Greenland using data collected by

5995-427: The Ellesmerian orogeny, the regional phase of the larger Caledonian orogeny in the Paleozoic Era. Regional subsidence in the Jurassic and Triassic periods led to significant sediment deposition, creating many of the reservoirs for current day oil and gas deposits. During the Cretaceous period, the Canadian Basin opened, and tectonic activity due to the assembly of Alaska caused hydrocarbons to migrate toward what

6104-407: The European region of the Arctic Ocean was heavily contested : the Allied commitment to resupply the Soviet Union via its northern ports was opposed by German naval and air forces. Since 1954 commercial airlines have flown over the Arctic Ocean (see Polar route ). The Arctic Ocean occupies a roughly circular basin and covers an area of about 14,056,000 km (5,427,000 sq mi), almost

6213-445: The Fram Strait with the Atlantic Basin , "where the circulation is dominated by thermohaline forcing". The Arctic Ocean has a total volume of 18.07 × 10 km, equal to about 1.3% of the World Ocean. Mean surface circulation is predominantly cyclonic on the Eurasian side and anticyclonic in the Canadian Basin . Water enters from both the Pacific and Atlantic Oceans and can be divided into three unique water masses. The deepest water mass

6322-510: The Gakkel Ridge in the Paleocene Epoch and the Eocene Epoch, causing the Lomonosov Ridge to move farther from land and subside. Because of sea ice and remote conditions, the geology of the Arctic Ocean is still poorly explored. The Arctic Coring Expedition drilling shed some light on the Lomonosov Ridge, which appears to be continental crust separated from the Barents-Kara Shelf in the Paleocene and then starved of sediment. It may contain up to 10 billion barrels of oil. The Gakkel Ridge rift

6431-437: The IHO (such as the Caribbean Sea and North Sea ), though these are usually considered to be part of the Atlantic Ocean. The 3rd edition (currently in force) of the International Hydrographic Organization 's (IHO) Limits of Oceans and Seas defines the limits of the South Atlantic Ocean (excluding the seas it contains) as follows: On the Southwest. The meridian of Cape Horn , Chile (67°16'W) from Tierra del Fuego to

6540-420: The Middle East; in 2019 salvage engineer Nick Sloane announced a plan to move one to South Africa at an estimated cost of $ 200 million. In 2019, a German company, Polewater, announced plans to tow Antarctic icebergs to places like South Africa. Companies have used iceberg water in products such as bottled water , fizzy ice cubes and alcoholic drinks. For example, Iceberg Beer by Quidi Vidi Brewing Company

6649-443: The North American polar region goes back at least 17,000–50,000 years, during the Wisconsin glaciation . At this time, falling sea levels allowed people to move across the Bering land bridge that joined Siberia to northwestern North America (Alaska), leading to the Settlement of the Americas . Early Paleo-Eskimo groups included the Pre-Dorset ( c.  3200–850 BC ); the Saqqaq culture of Greenland (2500–800 BC);

SECTION 60

#1732766286279

6758-414: The Northern limit of East Siberian Sea . From the Northern point of Wrangel Island to Point Barrow – the Northern limit of Chuckchi Sea [ sic ]. From Point Barrow to Cape Land's End on Prince Patrick Island – the Northern limit of Beaufort Sea , through the Northwest coast of Prince Patrick Island to Cape Leopold M'Clintock, thence to Cape Murray ( Brook Island [ sic ]) and along

6867-415: The Northwest coast to the extreme Northerly point; to Cape Mackay ( Borden Island ); through the Northwesterly coast of Borden Island to Cape Malloch, to Cape Isachsen ( Ellef Ringnes Island ); to the Northwest point of Meighen Island to Cape Stallworthy ( Axel Heiberg Island ) to Cape Colgate the extreme West point of Ellesmere Island ; through the North shore of Ellesmere Island to Cape Columbia thence

6976-423: The Siberian Shelf. As it is entrained, it cools and acts a heat shield for the surface layer on account of weak mixing between layers. However, over the past couple of decades a combination of the warming and the shoaling of Atlantic water are leading to the increasing influence of Atlantic water heat in melting sea ice in the eastern Arctic. The most recent estimates, for 2016–2018, indicate the oceanic heat flux to

7085-403: The Southeast. From Cape Agulhas along the meridian of 20° East to the Antarctic continent . On the South. The Antarctic Continent. Note that these definitions exclude any marginal waterbodies that are separately defined by the IHO (such as the Bay of Biscay and Gulf of Guinea ), though these are usually considered to be part of the Atlantic Ocean. In its 2002 draft, the IHO redefined

7194-407: The Southeastern limits of the Gulf of Mexico from the North coast of Cuba to Key West , the Southwestern limit of the Bay of Fundy and the Southeastern and Northeastern limits of the Gulf of St. Lawrence . On the North. The Southern limit of Davis Strait from the coast of Labrador to Greenland and the Southwestern limit of the Greenland Sea and Norwegian Sea from Greenland to

7303-483: The World Ocean, such as the Caspian Sea (which is nevertheless, geologically, itself a full-fledged ocean—see above) and numerous salt lakes such as the Aral Sea . A complete hierarchy showing which seas belong to which oceans, according to the International Hydrographic Organization (IHO), is available at the European Marine Gazetteer website. See also the list of seas article for the seas included in each ocean area. Also note there are many varying definitions of

7412-430: The border between Russian and the United States as stated in the USSR–USA Maritime Boundary Agreement . The whole area is subject to international territorial claims . The Chukchi Plateau extends from the Chukchi Sea Shelf. An underwater ridge , the Lomonosov Ridge , divides the deep sea North Polar Basin into two oceanic basins : the Eurasian Basin , which is 4,000–4,500 m (13,100–14,800 ft) deep, and

7521-474: The case of Pobeda Ice Island . Antarctic icebergs formed by breaking off from an ice shelf , such as the Ross Ice Shelf or Filchner–Ronne Ice Shelf , are typically tabular. The largest icebergs in the world are formed this way. Non-tabular icebergs have different shapes and include: Prior to 1914 there was no system in place to track icebergs to guard ships against collisions despite fatal sinkings of ships by icebergs. In 1907, SS Kronprinz Wilhelm ,

7630-578: The effectiveness of radar in detecting icebergs. A decade later, oceanographic monitoring outposts were established for the purpose of collecting data; these outposts continue to serve in environmental study. A computer was first installed on a ship for the purpose of oceanographic monitoring in 1964, which allowed for a faster evaluation of data. By the 1970s, ice-breaking ships were equipped with automatic transmissions of satellite photographs of ice in Antarctica. Systems for optical satellites had been developed but were still limited by weather conditions. In

7739-436: The explorers who travelled closer and closer to the pole reported, the polar ice cap is quite thick and persists year-round. Fridtjof Nansen was the first to make a nautical crossing of the Arctic Ocean, in the Fram Expedition from 1893 to 1896. The first surface crossing of the ocean was led by Wally Herbert in 1969, in a dog sled expedition from Alaska to Svalbard , with air support. The first nautical transit of

7848-487: The ice can create diverse colors. Sediment can create the dirty black coloration present in some icebergs. In addition to size classification (Table 1), icebergs can be classified on the basis of their shapes. The two basic types of iceberg forms are tabular and non-tabular . Tabular icebergs have steep sides and a flat top, much like a plateau , with a length-to-height ratio of more than 5:1. This type of iceberg, also known as an ice island , can be quite large, as in

7957-453: The ice has been quoted at 50%. The US National Snow and Ice Data Center (NSIDC) uses satellite data to provide a daily record of Arctic sea ice cover and the rate of melting compared to an average period and specific past years, showing a continuous decline in sea ice extent. In September 2012, the Arctic ice extent reached a new record minimum. Compared to the average extent (1979–2000), the sea ice had diminished by 49%. Human habitation in

8066-518: The iceberg is young and establishing balance. Icebergs are unpredictable and can capsize anytime and without warning. Large icebergs that break off from a glacier front and flip onto the glacier face can push the entire glacier backwards momentarily, producing 'glacial earthquakes' that generate as much energy as an atomic bomb. Icebergs are generally white because they are covered in snow, but can be green, blue, yellow, black, striped, or even rainbow -colored. Seawater, algae and lack of air bubbles in

8175-765: The iron contained in sediments, can fuel blooms of phytoplankton. Samples collected from icebergs in Antarctica, Patagonia, Greenland, Svalbard, and Iceland, however, show that iron concentrations vary significantly, complicating efforts to generalize the impacts of icebergs on marine ecosystems. Iceberg B15 calved from the Ross Ice Shelf in 2000 and initially had an area of 11,000 square kilometres (4,200 sq mi). It broke apart in November 2002. The largest remaining piece of it, Iceberg B-15A , with an area of 3,000 square kilometres (1,200 sq mi),

8284-478: The latter being a relatively new addition identified with a distinct ecosystem and a unique impact on global climate. In turn, oceanic waters are interspersed by many smaller seas, gulfs, and bays. If viewed from the southern pole of Earth, the Atlantic, Indian, and Pacific Oceans can be seen as lobes extending northward from the Southern Ocean. Farther north, the Atlantic opens into the Arctic Ocean, which

8393-496: The limits of the Indian Ocean (excluding the seas it contains) as follows: Note that this definition excludes any marginal waterbodies that are separately defined by the IHO (such as the Bay of Bengal and Arabian Sea ), though these are usually considered to be part of the Indian Ocean. In its 2002 draft, the IHO redefined the Indian Ocean, moving its southern limit to 60°S, with the waters south of that line identified as

8502-552: The limits of the North Pacific Ocean (excluding the seas it contains) as follows: The 3rd edition, currently in force, of the International Hydrographic Organization 's (IHO) Limits of Oceans and Seas defines the limits of the South Pacific Ocean (excluding the seas it contains) as follows: Note that these definitions exclude any marginal waterbodies that are separately defined by the IHO (such as

8611-436: The mass m , as well as the surface area, volume, and stability of the iceberg. Iceberg deterioration and drift, therefore, are interconnected ie. iceberg thermodynamics, and fracturing must be considered when modelling iceberg drift. Winds and currents may move icebergs close to coastlines, where they can become frozen into pack ice (one form of sea ice ), or drift into shallow waters, where they can come into contact with

8720-549: The maximum in April and minimum in September. The sea ice is affected by wind and ocean currents, which can move and rotate very large areas of ice. Zones of compression also arise, where the ice piles up to form pack ice. Icebergs occasionally break away from northern Ellesmere Island , and icebergs are formed from glaciers in western Greenland and extreme northeastern Canada. Icebergs are not sea ice but may become embedded in

8829-483: The more fanciful cartographers, tended to leave the region blank, with only fragments of known coastline sketched in. This lack of knowledge of what lay north of the shifting barrier of ice gave rise to a number of conjectures. In England and other European nations, the myth of an " Open Polar Sea " was persistent. John Barrow , longtime Second Secretary of the British Admiralty , promoted exploration of

8938-497: The north polar regions remained largely unexplored and their geography conjectural. Pytheas of Massilia recorded an account of a journey northward in 325 BC, to a land he called " Eschate Thule ", where the Sun only set for three hours each day and the water was replaced by a congealed substance "on which one can neither walk nor sail". He was probably describing loose sea ice known today as " growlers " or "bergy bits"; his "Thule"

9047-399: The north pole was made in 1958 by the submarine USS Nautilus , and the first surface nautical transit occurred in 1977 by the icebreaker NS Arktika . Since 1937, Soviet and Russian manned drifting ice stations have extensively monitored the Arctic Ocean. Scientific settlements were established on the drift ice and carried thousands of kilometres by ice floes . In World War II ,

9156-506: The ocean can be modelled by integrating the equation where m is the iceberg mass, v the drift velocity, and the variables f , k , and F correspond to the Coriolis force , the vertical unit vector, and a given force. The subscripts a, w, r, s, and p correspond to the air drag, water drag, wave radiation force, sea ice drag, and the horizontal pressure gradient force. Icebergs deteriorate through melting and fracturing, which changes

9265-498: The oceans are the limits of Earth 's oceanic waters . The definition and number of oceans can vary depending on the adopted criteria. The principal divisions (in descending order of area) of the five oceans are the Pacific Ocean , Atlantic Ocean , Indian Ocean , Southern (Antarctic) Ocean , and Arctic Ocean . Smaller regions of the oceans are called seas , gulfs , bays , straits , and other terms. Geologically, an ocean

9374-577: The pack ice. Icebergs pose a hazard to ships, of which the Titanic is one of the most famous. The ocean is virtually icelocked from October to June, and the superstructure of ships are subject to icing from October to May. Before the advent of modern icebreakers, ships sailing the Arctic Ocean risked being trapped or crushed by sea ice (although the Baychimo drifted through the Arctic Ocean untended for decades despite these hazards). The Arctic Ocean

9483-410: The parallel of lat. 80° N . From Cape Leigh Smith to Cape Kohlsaat – the Northern limit of Barentsz Sea [ sic ]. From Cape Kohlsaat to Cape Molotov – the Northern limit of Kara Sea . From Cape Molotov to the Northern extremity of Kotelni Island – the Northern limit of Laptev Sea . From the Northern extremity of Kotelni Island to the Northern point of Wrangel Island –

9592-563: The phase of the Arctic Oscillation and Atlantic Multidecadal Oscillation . Much of the Arctic Ocean is covered by sea ice that varies in extent and thickness seasonally. The mean extent of the Arctic sea ice has been continuously decreasing in the last decades, declining at a rate of currently 12.85% per decade since 1980 from the average winter value of 15,600,000 km (6,023,200 sq mi). The seasonal variations are about 7,000,000 km (2,702,700 sq mi), with

9701-527: The region from 1818 to 1845 in search of this. In the United States in the 1850s and 1860s, the explorers Elisha Kane and Isaac Israel Hayes both claimed to have seen part of this elusive body of water. Even quite late in the century, the eminent authority Matthew Fontaine Maury included a description of the Open Polar Sea in his textbook The Physical Geography of the Sea (1883). Nevertheless, as all

9810-934: The remainder of the ice season of that year, the United States Navy patrolled the waters and monitored ice movements. In November 1913, the International Conference on the Safety of Life at Sea met in London to devise a more permanent system of observing icebergs. Within three months the participating maritime nations had formed the International Ice Patrol (IIP). The goal of the IIP was to collect data on meteorology and oceanography to measure currents, ice-flow, ocean temperature , and salinity levels. They monitored iceberg dangers near

9919-442: The same orbit path as RADARSAT-1. Iceberg concentrations and size distributions are monitored worldwide by the U.S. National Ice Center (NIC), established in 1995, which produces analyses and forecasts of Arctic , Antarctic , Great Lakes and Chesapeake Bay ice conditions. More than 95% of the data used in its sea ice analyses are derived from the remote sensors on polar-orbiting satellites that survey these remote regions of

10028-463: The same salinity as Arctic Bottom Water but is much warmer (up to 3 °C [37 °F]). In fact, this water mass is actually warmer than the surface water and remains submerged only due to the role of salinity in density. When water reaches the basin, it is pushed by strong winds into a large circular current called the Beaufort Gyre . Water in the Beaufort Gyre is far less saline than that of

10137-430: The sea state, T S {\displaystyle T_{\text{S}}} is the sea surface temperature, and I c {\displaystyle I_{\text{c}}} is the sea ice concentration. Air trapped in snow forms bubbles as the snow is compressed to form firn and then glacial ice. Icebergs can contain up to 10% air bubbles by volume. These bubbles are released during melting, producing

10246-575: The sea surface are classified as "bergy bits"; smaller than 1 meter—"growlers". The largest known iceberg in the North Atlantic was 168 metres (551 ft) above sea level, reported by the USCG icebreaker Eastwind in 1958, making it the height of a 55-story building. These icebergs originate from the glaciers of western Greenland and may have interior temperatures of −15 to −20 °C (5 to −4 °F). A given iceberg's trajectory through

10355-438: The seabed, a phenomenon called seabed gouging . Icebergs lose mass due to melting, and calving . Melting can be due to solar radiation, or heat and salt transport from the ocean. Iceberg calving is generally enhanced by waves impacting the iceberg. Melting tends to be driven by the ocean, rather than solar radiation. Ocean driven melting is often modelled as where M b {\displaystyle M_{\text{b}}}

10464-426: The seawater in the vicinity of the iceberg. Fresh melt water released at depth is lighter, and therefore more buoyant, than the surrounding seawater causing it to rise towards the surface. Icebergs can also act as floating breakwaters , impacting ocean waves. Icebergs contain variable concentrations of nutrients and minerals that are released into the ocean during melting. Iceberg-derived nutrients, particularly

10573-406: The size of Antarctica . The coastline is 45,390 km (28,200 mi) long. It is the only ocean smaller than Russia , which has a land area of 16,377,742 km (6,323,482 sq mi). The Arctic Ocean is surrounded by the land masses of Eurasia (Russia and Norway), North America ( Canada and the U.S. state of Alaska), Greenland, and Iceland . Note: Some parts of the areas listed in

10682-432: The surface has now overtaken the atmospheric flux in the eastern Eurasian Basin. Over the same period the weakening halocline stratification has coincided with increasing upper ocean currents thought to be associated with declining sea ice, indicate increasing mixing in this region. In contrast direct measurements of mixing in the western Arctic indicate the Atlantic water heat remains isolated at intermediate depths even under

10791-569: The table are located in the Atlantic Ocean . Other consists of Gulfs , Straits , Channels and other parts without specific names and excludes Exclusive Economic Zones . The Arctic Ocean is connected to the Pacific Ocean by the Bering Strait and to the Atlantic Ocean through the Greenland Sea and Labrador Sea . (The Iceland Sea is sometimes considered part of the Greenland Sea, and sometimes separate.) The largest seas in

10900-448: The underwater portion can be difficult to judge by looking at the portion above the surface. The largest icebergs recorded have been calved , or broken off, from the Ross Ice Shelf of Antarctica . Icebergs may reach a height of more than 100 metres (300 ft) above the sea surface and have mass ranging from about 100,000 tonnes up to more than 10 million tonnes. Icebergs or pieces of floating ice smaller than 5 meters above

11009-474: The upper 100–150 m (330–490 ft) of ocean water cools to the freezing point for sea ice to form. In the winter, the relatively warm ocean water exerts a moderating influence, even when covered by ice. This is one reason why the Arctic does not experience the extreme temperatures seen on the Antarctic continent . There is considerable seasonal variation in how much pack ice of the Arctic ice pack covers

11118-490: The water of which quasi floats on the saltier, denser, deeper ocean water. Between this lower salinity layer and the bulk of the ocean lies the so-called halocline , in which both salinity and temperature rise with increasing depth. Because of its relative isolation from other oceans, the Arctic Ocean has a uniquely complex system of water flow. It resembles some hydrological features of the Mediterranean Sea , referring to its deep waters having only limited communication through

11227-423: The winter, ice forms, and intense vertical convection allows the water to become dense enough to sink below the warm saline water below. Arctic Bottom Water is critically important because of its outflow, which contributes to the formation of Atlantic Deep Water. The overturning of this water plays a key role in global circulation and the moderation of climate. In the depth range of 150–900 m (490–2,950 ft)

11336-483: The world's seas and no single authority. The world ocean is divided into a number of principal oceanic areas that are delimited by the continents and various oceanographic features: these divisions are the Atlantic Ocean , Arctic Ocean (sometimes considered an estuary of the Atlantic), Indian Ocean , Pacific Ocean , and the Southern Ocean , defined by the International Hydrographic Organization (IHO) in 2000,

11445-479: Was measured at nearly 300 by 40 kilometres (186 by 25 mi) in 2000. The largest iceberg on record was an Antarctic tabular iceberg measuring 335 by 97 kilometres (208 by 60 mi) sighted 240 kilometres (150 mi) west of Scott Island , in the South Pacific Ocean, by the USS Glacier on November 12, 1956. This iceberg was larger than Belgium . The word iceberg is a partial loan translation from

11554-450: Was painted from sketches Church completed on a boat trip off Newfoundland and Labrador. Caspar David Friedrich , The Sea of Ice , 1823–1824 is polar landscape with an iceberg and ship wreck depicting the dangers of such conditions . William Bradford created detailed paintings of sailing ships set in arctic coasts and was fascinated by icebergs. Albert Bierstadt made studies on arctic trips aboard steamships in 1883 and 1884 that were

11663-673: Was probably Norway , though the Faroe Islands or Shetland have also been suggested. Early cartographers were unsure whether to draw the region around the North Pole as land (as in Johannes Ruysch 's map of 1507, or Gerardus Mercator 's map of 1595) or water (as with Martin Waldseemüller 's world map of 1507). The fervent desire of European merchants for a northern passage, the Northern Sea Route or

11772-419: Was still the largest iceberg on Earth until it ran aground and split into several pieces October 27, 2005, an event that was observed by seismographs both on the iceberg and across Antarctica. It has been hypothesized that this breakup may also have been abetted by ocean swell generated by an Alaskan storm 6 days earlier and 13,500 kilometres (8,400 mi) away. One of the most infamous icebergs in history

11881-578: Was the first to use synthetic aperture radar (SAR), which sends microwave energy to the ocean surface and records the reflections to track icebergs. The European Space Agency launched ENVISAT (an observation satellite that orbits the Earth's poles) on March 1, 2002. ENVISAT employs advanced synthetic aperture radar (ASAR) technology, which can detect changes in surface height accurately. The Canadian Space Agency launched RADARSAT-2 in December 2007, which uses SAR and multi-polarization modes and follows

#278721