|Earth's five Oceans|
The Arctic Ocean, located entirely in the north polar region, is the smallest of the world's five oceans (after the Pacific Ocean, Atlantic Ocean, Indian Ocean, and Southern Ocean), and the shallowest.
It occupies a roughly circular basin and covers an area of about 14,090,000 kmē (5,440,000 sq mi). Nearly landlocked, the ocean is surrounded by the land masses of Europe, Asia, North America, and Greenland and a number of islands, as well as by the Barents, Beaufort, Chukchi, Kara, Laptev, East Siberian, Lincoln , Wandel , Greenland , and Norwegian seas. It is connected to the Pacific Ocean by the Bering Strait and to the Atlantic Ocean through the Greenland Sea.
An underwater ocean ridge, the Lomonosov ridge, divides the Arctic Ocean into two basins: the Eurasian, or Nansen, Basin, which is between 4,000 and 4,500 m (13,000 and 15,000 ft) deep, and the North American, or Hyperborean, Basin, which is about 4,000 m deep. The topography of the ocean bottom is marked by fault-block ridges, plains of the abyssal zone, ocean deeps, and basins.
The greatest inflow of water comes from the Atlantic by way of the Norwegian Current , which then flows along the Eurasian coast. Water also enters from the Pacific via the Bering Strait. The East Greenland Current carries the major outflow. Temperature and salinity vary seasonally as the ice cover melts and freezes. Ice covers most of the ocean surface year-round, causing subfreezing temperatures much of the time. The Arctic is a major source of very cold air that inevitably moves toward the equator, meeting with warmer air in the middle latitudes and causing rain and snow. Little marine life exists where the ocean surface is covered with ice throughout the year. Marine life abounds in open areas, especially the more southerly waters. The ocean's major ports are the Russian cities of Murmansk and Arkhangelsk (Archangel). The Arctic Ocean is important as the shortest air route between the Pacific coast of North America and Europe.
Body of water mostly north of the Arctic Circle
90 00 N, 0 00 E
- total:14.056 million kmē
- note: includes Back's River, Baffin Bay, Barents Sea, Beaufort Sea, Chukchi Sea, East Siberian Sea, Greenland Sea , Hudson Bay, Hudson Strait, Kara Sea, Laptev Sea, White Sea, Northwest Passage and other tributary bodies of water
Area - comparative
Slightly less than 1.5 times the size of the US
Polar climate characterized by persistent cold and relatively narrow annual temperature ranges; winters characterized by continuous darkness, cold and stable weather conditions, and clear skies; summers characterized by continuous daylight, damp and foggy weather, and weak cyclones with rain or snow
Central surface covered by a perennial drifting polar icepack that averages about 3 meters in thickness, although pressure ridges may be three times that size; clockwise drift pattern in the Beaufort Gyral Stream , but nearly straight-line movement from the New Siberian Islands (Russia) to Denmark Strait (between Greenland and Iceland); the icepack is surrounded by open seas during the summer, but more than doubles in size during the winter and extends to the encircling landmasses; the ocean floor is about 50% continental shelf (the highest percentage of any ocean) with the remainder a central basin interrupted by three submarine ridges (Alpha Cordillera , Nansen Cordillera , and Lomonosov Ridge )
- lowest point: Fram Basin -4,665 m
- highest point: sea level 0 m
Ice islands occasionally break away from northern Ellesmere Island; icebergs calved from glaciers in western Greenland and extreme northeastern Canada; permafrost on islands; virtually ice locked from October to June; ships subject to superstructure icing from October to May
Environment - current issues
Endangered marine species include walruses and whales; fragile ecosystem slow to change and slow to recover from disruptions or damage; thinning polar icepack; seasonal hole in ozone layer over the North Pole
Reduction of the area of Arctic sea ice will have an effect on the planet's albedo, thus affecting global warming. Many scientists are presently concerned that warming temperatures in the Arctic may cause large amounts of fresh, Arctic Ocean meltwater to enter the North Atlantic, possibly disrupting global ocean current patterns. Potentially severe changes in the Earth's climate might then ensue.
Geography - note
Major chokepoint is the southern Chukchi Sea (northern access to the Pacific Ocean via the Bering Strait); strategic location between North America and Russia; shortest marine link between the extremes of eastern and western Russia; floating research stations operated by the US and Russia; maximum snow cover in March or April about 20 to 50 centimeters over the frozen ocean; snow cover lasts about 10 months.
Extent of the ice-pack
There is considerable seasonal variation in how much pack ice covers the Arctic Ocean.
Ports and harbors
Transportation - note
Bibliography: Neatby, L. H., Discovery in Russian and Siberian Waters (1973); Ray, L., and Stonehouse, B., eds., The Arctic Ocean (1982) Thoren, Ragnar, Picture Atlas of the Arctic (1969).
Based on public domain text by US Naval Oceanographer: http://oceanographer.navy.mil/arctic.html
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