Everything about Arctic Sea totally explained
The
Arctic Ocean, located in the
northern hemisphere and mostly in the
Arctic north polar region, is the smallest of the world's five major
oceanic divisions and the shallowest. The
International Hydrographic Organization (IHO) recognizes it as an ocean, although some
oceanographers may call it the
Arctic Mediterranean Sea or simply the
Arctic Sea, classifying it as one of the
mediterranean seas of the
Atlantic Ocean. Alternatively, the Arctic Ocean can be seen as the northernmost lobe of the all-encompassing
World Ocean.
Almost completely surrounded by
Eurasia and
North America, the Arctic Ocean is largely covered by
sea ice throughout the year. The Arctic Ocean's
temperature and
salinity vary
seasonally as the ice cover melts and freezes; its salinity is the lowest on average of the five major seas, due to low
evaporation, heavy freshwater inflow from rivers and streams, and limited connection and outflow to surrounding oceanic waters with higher salinities. The summer shrinking of the icepack has been quoted at 50%. The coastline length is 45,390 kilometers (28,203 mi). the limits of the Arctic Ocean proper are (see
the map
):
- A great circle line running from Cape Morris Jesup, the northernmost point of Greenland to the northernmost point of Spitsbergen (south of which line lies the Greenland Sea).
- Parallel 80° North to North East Land (Nordaustlandet).
- The north shore of Nordaustlandet to its easternmost point, Cape Leigh Smith .
- A line running from Cape Leigh Smith to Cape Kohlsaat, the easternmost point of Franz Josef Land (south of which line lies the Barents Sea).
- A line running from Cape Kohlsaat to Cape Molotov (Arctic Cape), the northernmost point of Komsomolets Island (south of which line lies the Kara Sea).
- A line running from Arctic Cape to the northernmost point of Kotelni Island (south of which line lies the Laptev Sea).
- A line running from the northernmost point of Kotelni Island to the northernmost point of Wrangel Island (south of which line lies the East Siberian Sea).
- A line running from the northernmost point of Wrangel Island to Point Barrow, the northernmost point of Alaska (south of which line lies the Chuckchi Sea).
- A line running from Point Barrow to Cape Land's End on Prince Patrick Island, Northwest Territories (south of which line lies the Beaufort Sea).
- The northwest coast of Prince Patrick Island north to Cape Leopold M'Clintock, its northernmost point .
- A line running from Cape Leopold M'Clintock to Cape Murray on Brock Island .
- The northwest coast of Brock Island north, to its northernmost point .
- A line running from the northernmost point of Brook Island to Cape Mackay on Borden Island, its westernmost point .
- The northwest coast of Borden Island north to Cape Malloch (the northernmost point of the Northwest Territories).
- A line running from Cape Malloch to Cape Isachsen on Ellef Ringnes Island, Nunavut, its northwesternmost point .
- A line running from Cape Isachsen to the northwesternmost point of Meighen Island .
- A line running from the northwesternmost point of Meighen Island to Cape Stallworthy on Axel Heiberg Island, its northernmost point .
- A line running from Cape Stallworthy to Cape Colgate on Ellesmere Island, its westernmost point .
- The north coast of Ellesmere Island north to Cape Columbia, its northernmost point .
- A line running from Cape Columbia to Cape Morris Jesup (south of which line lies the Lincoln Sea).
An underwater ridge, the
Lomonosov Ridge, divides the deep sea
North Polar Basin into two basins: the
Eurasian Basin, which is between 4,000 and 4,500 meters (13,000 and 15,000 ft) deep, and the
Amerasian Basin (sometimes called
North American, or
Hyperborean), which is about 4,000 meters (13,000 ft) deep. The
bathymetry of the ocean bottom is marked by
fault-block ridges,
plains of the abyssal zone, ocean deeps, and basins. The average depth of the Arctic Ocean is 1,038 meters (3,407 ft). The deepest point is in the Eurasian Basin, at 5,450 meters (17,881 ft).
The two major basins are further subdivided by ridges into the
Canada Basin (between
Alaska/
Canada and the
Alpha Ridge),
Makarov Basin (between the Alpha and Lomonosov Ridges),
Fram Basin (between Lomonosov and
Nansen-Gakkel ridges), and
Nansen Basin (
Amundsen Basin) (between the Nansen-Gakkel Ridge and the
continental shelf that includes the
Franz Joseph Land).
The Arctic Ocean contains a major chokepoint in the southern Chukchi Sea, which provides northern access to the
Pacific Ocean via the
Bering Strait between North America and
Russian city of
Arkhangelsk. The Arctic Ocean also provides the shortest marine link between the extremes of eastern and western Russia. There are several floating research stations in the Arctic, operated by the U.S. and Russia.
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.
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. Marine life abounds in open areas, especially the more southerly waters. The ocean's major ports are the
Russian cities of
Murmansk and
Arkhangelsk,
Churchill, Manitoba (Canada) and
Prudhoe Bay, Alaska (US).
Early cartographers were unsure whether to draw the region around the
North Pole as land (as in
Johannes Ruysch's, or
Gerardus Mercator's ) or water (as with
Martin Waldseemüller's ). The fervent desire of Europeans for a northern 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 this era added only small islands, such as
Nova Zemlya (11th century) and
Spitsbergen (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 the more fanciful cartographers, tended to leave the region blank, with only the bits 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 long-lived and persistent.
John Barrow, longtime Second Secretary of the
British Admiralty, made this belief the cornerstone of his campaign of
Arctic exploration from 1818 to 1845. In the
United States in the 1850s and '60s, the explorers
Elisha Kent Kane and
Isaac Israel Hayes both claimed to have seen the outskirts 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 the explorers who trekked closer and closer to the pole reported, the Polar Ice Cap was ultimately quite thick, and persists year-round.
Fridtjof Nansen was the first to make a naval crossing of the Arctic Ocean in 1896. The first surface crossing of the Arctic Ocean was led by
Wally Herbert in 1969, in a
dog sled expedition from
Alaska to
Svalbard with air support.
Since 1937
Soviet and Russian manned drifting ice stations extensively monitored the Arctic Ocean. Scientific settlements were established on the
drift ice and carried thousands of kilometers by ice floes.
Climate
| The images compare late summer and late winter ice cover, averaged between the years 1978 and 2002. |
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Under the influence of the present
ice age, the ocean is contained in a
polar climate characterized by persistent cold and relatively narrow annual temperature ranges. Winters are characterized by continuous darkness, cold and stable weather conditions, and clear skies; summers are characterized by continuous daylight, damp and foggy weather, and weak cyclones with rain or snow.
The temperature of the surface of the Arctic Ocean is fairly constant, near the freezing point of seawater, slightly below zero degrees Celsius. In the winter the relatively warm ocean water exerts a moderating influence, even when covered by ice. This is one reason why the Arctic doesn't experience the extremes of temperature seen on the
Antarctic continent.
There is considerable seasonal variation in how much
pack ice of the
Arctic ice pack covers the Arctic Ocean. Much of the ocean is also covered in snow for about 10 months of the year. The maximum snow cover is in March or April — about 20 to 50 centimeters (8 to 20 in) over the frozen ocean.
Climate has varied significantly in the past; as recently as 55 million years ago, during the
Paleocene–Eocene Thermal Maximum the region reached an average annual temperature of 10-20; the surface waters of the northernmost Arctic ocean warmed, seasonally at least, enough to support tropical lifeforms requiring surface temperatures of over 22°C.
Natural resources
See also Territorial claims in the Arctic
Petroleum and gas fields,
placer deposits,
polymetallic nodules, sand and gravel aggregates,
fish,
seals and
whales can all be found in abundance in the region. It is considered significant because of its potential to contain as much as or more than a quarter of the world's undiscovered oil and gas resources, the tapping of which could greatly alter the flow of the global energy market.
Natural hazards
Ice islands occasionally break away from northern
Ellesmere Island, and icebergs are formed from glaciers in western Greenland and extreme northeastern Canada.
Permafrost is found on most islands. The ocean is virtually ice locked from October to June, and ships are subject to superstructure icing from October to May. During summer, the sun is out day and night, thus enabling the phytoplankton to
photosynthesize for long periods of time and reproduce quickly. However, the reverse is true in winter where they struggle to get enough light to survive.]]
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The
polar ice pack is thinning, and there's a seasonal hole in
ozone layer in many years.
Reduction of the area of Arctic sea ice will have an effect on the planet's
albedo, thus possibly affecting
global warming within a positive feedback mechanism. Many scientists are presently concerned that warming temperatures in the Arctic may cause large amounts of fresh meltwater to enter the North Atlantic, possibly disrupting global
ocean current patterns. Potentially severe changes in the Earth's climate might then ensue. and
Cold War nuclear test sites such as
Novaya Zemlya.
Major ports and harbors
Churchill, Manitoba, Canada[
Inuvik, Canada
Prudhoe Bay, Alaska, United States][
Barrow, Alaska, United States
Pevek, Russia
Tiksi, Russia
Dikson, Russia
Dudinka, Russia
Murmansk, Russia][
Arkhangelsk, Russia
Kirkenes, Norway
Vardø, Norway
Longyearbyen, Spitsbergen, NorwayFurther Information]
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