Jump to content

Arctic Circle: Difference between revisions

From Wikipedia, the free encyclopedia
Content deleted Content added
Thesevenseas (talk | contribs)
Removed Northern Hemisphere Bias
Fix
Line 12: Line 12:
The Arctic Circle marks the southern extremity of the [[midnight sun|polar day]] (24-hour sunlit day, often referred to as the "midnight sun") and [[polar night]] (24-hour sunless night). North of the Arctic Circle, the [[sun]] is above the [[horizon]] for 24 continuous [[hour]]s at least once per [[year]] and below the horizon for 24 continuous hours at least once per year. On the Arctic Circle those events occur, in principle, exactly once per year, at the June and December [[solstice]]s, respectively.
The Arctic Circle marks the southern extremity of the [[midnight sun|polar day]] (24-hour sunlit day, often referred to as the "midnight sun") and [[polar night]] (24-hour sunless night). North of the Arctic Circle, the [[sun]] is above the [[horizon]] for 24 continuous [[hour]]s at least once per [[year]] and below the horizon for 24 continuous hours at least once per year. On the Arctic Circle those events occur, in principle, exactly once per year, at the June and December [[solstice]]s, respectively.


In fact, because of [[atmospheric refraction]] and because the sun appears as a disk and not a point, part of the midnight sun may be seen on the night of the [[June Solstice]] up to about 50[[Minute|′]] ({{convert|90|km|abbr=on}}) south of the Arctic Circle; similarly, on the day of the [[December Solstice]], part of the sun may be seen up to about 50′ north of the Arctic Circle. That is true at sea level; those limits increase with elevation above sea level although in mountainous regions, there is often no direct view of the horizon.
In fact, because of [[atmospheric refraction]] and because the sun appears as a disk and not a point, part of the midnight sun may be seen on the night of the [[summer solstice]] ([[Northern Hemisphere]]) up to about 50[[Minute|′]] ({{convert|90|km|abbr=on}}) south of the Arctic Circle; similarly, on the day of the [[winter solstice]] (Northern Hemisphere), part of the sun may be seen up to about 50′ north of the Arctic Circle. That is true at sea level; those limits increase with elevation above sea level although in mountainous regions, there is often no direct view of the horizon.


The position of the Arctic Circle is not fixed, but directly depends on the Earth's [[axial tilt]], which fluctuates within a margin of 2° over a 40,000 year period,<ref>[http://www.communique.se/polcirkel/arctic.html Arctic Circle]</ref> notably due to [[tidal force]]s resulting from the [[orbit of the Moon]]. The Arctic Circle is currently drifting northwards at a speed of about {{convert|15|m|abbr=on}} per year, see [[circle of latitude#Movement_of_the_Tropical_and_Polar_circles|''Circle of latitude'']] for more information.
The position of the Arctic Circle is not fixed, but directly depends on the Earth's [[axial tilt]], which fluctuates within a margin of 2° over a 40,000 year period,<ref>[http://www.communique.se/polcirkel/arctic.html Arctic Circle]</ref> notably due to [[tidal force]]s resulting from the [[orbit of the Moon]]. The Arctic Circle is currently drifting northwards at a speed of about {{convert|15|m|abbr=on}} per year, see [[circle of latitude#Movement_of_the_Tropical_and_Polar_circles|''Circle of latitude'']] for more information.

Revision as of 01:16, 12 September 2010

World map showing the Arctic Circle in red.
Map of the Arctic with the Arctic Circle in blue.

The Arctic Circle is one of the five major circles of latitude that mark maps of the Earth. For Epoch 2010, it is the parallel of latitude that runs 66°33′50.2″ (or 66.56394°) north of the Equator.[1]

The region north of this circle is known as the Arctic, and the zone just to the south is called the Northern Temperate Zone. The equivalent polar circle in the Southern Hemisphere is called the Antarctic Circle.

The Arctic Circle marks the southern extremity of the polar day (24-hour sunlit day, often referred to as the "midnight sun") and polar night (24-hour sunless night). North of the Arctic Circle, the sun is above the horizon for 24 continuous hours at least once per year and below the horizon for 24 continuous hours at least once per year. On the Arctic Circle those events occur, in principle, exactly once per year, at the June and December solstices, respectively.

In fact, because of atmospheric refraction and because the sun appears as a disk and not a point, part of the midnight sun may be seen on the night of the summer solstice (Northern Hemisphere) up to about 50 (90 km (56 mi)) south of the Arctic Circle; similarly, on the day of the winter solstice (Northern Hemisphere), part of the sun may be seen up to about 50′ north of the Arctic Circle. That is true at sea level; those limits increase with elevation above sea level although in mountainous regions, there is often no direct view of the horizon.

The position of the Arctic Circle is not fixed, but directly depends on the Earth's axial tilt, which fluctuates within a margin of 2° over a 40,000 year period,[2] notably due to tidal forces resulting from the orbit of the Moon. The Arctic Circle is currently drifting northwards at a speed of about 15 m (49 ft) per year, see Circle of latitude for more information.


Geography

Relatively few people live north of the Arctic Circle due to the Arctic climate. The three largest communities above the Arctic Circle are situated in Russia; Murmansk (population 325,100), Norilsk (135,000), and Vorkuta (85,000). Tromsø (in Norway) has about 62,000 inhabitants. In contrast, the largest North American community north of the circle, Barrow, Alaska, has approximately 4,000 inhabitants. Rovaniemi (in Finland), which lies slightly south of the line, has a population of approximately 58,000, and is the largest settlement in the immediate vicinity of the Arctic Circle.

The Arctic Circle passes through the Arctic Ocean, the Scandinavian Peninsula, North Asia, Northern America and Greenland. The land on the Arctic Circle is divided among eight countries: Norway, Sweden, Finland, Russia, the United States (i.e. Alaska), Canada, Denmark (i.e. Greenland) and passes through the small Icelandic island of Grímsey just north of Iceland.

Starting at the Prime Meridian and heading eastwards, the Arctic Circle passes through:

Co-ordinates Country, territory or sea Notes
66°34′N 000°00′E / 66.567°N 0.000°E / 66.567; 0.000 (01 Prime Meridian)  Arctic Ocean Norwegian Sea
66°34′N 012°48′E / 66.567°N 12.800°E / 66.567; 12.800 (02 Nordland County, Norway)  Norway Nordland County
66°34′N 015°31′E / 66.567°N 15.517°E / 66.567; 15.517 (03 Norrbotten County, Sweden)  Sweden Norrbotten County
66°34′N 023°51′E / 66.567°N 23.850°E / 66.567; 23.850 (04 Lapland Province, Finland)  Finland Lapland Province
66°34′N 029°28′E / 66.567°N 29.467°E / 66.567; 29.467 (05 Karelia & Murmansk, Russia)  Russia Republic of Karelia
Murmansk Oblast
Karelia again
Murmansk again
66°34′N 033°25′E / 66.567°N 33.417°E / 66.567; 33.417 (06 Kandalaksha Gulf, White Sea) White Sea Kandalaksha Gulf
66°34′N 034°28′E / 66.567°N 34.467°E / 66.567; 34.467 (07 Murmansk Oblast, Russia)  Russia Murmansk Oblast – for about 7 km (4.3 mi)
66°34′N 034°38′E / 66.567°N 34.633°E / 66.567; 34.633 (08 Kandalaksha Gulf, White Sea) White Sea Kandalaksha Gulf
66°34′N 035°00′E / 66.567°N 35.000°E / 66.567; 35.000 (09 Murmansk Oblast, Kola Peninsula, Russia)  Russia Murmansk Oblast (Kola Peninsula)
66°34′N 040°42′E / 66.567°N 40.700°E / 66.567; 40.700 (10 White Sea) White Sea
66°34′N 044°23′E / 66.567°N 44.383°E / 66.567; 44.383 (11 Nenets Autonomous Okrug, Komi Republic & Yamalo-Nenets Autonomous Okrug, Russia)  Russia Nenets Autonomous Okrug
Komi Republic
Yamalo-Nenets Autonomous Okrug
66°34′N 071°05′E / 66.567°N 71.083°E / 66.567; 71.083 (12 Gulf of Ob) Gulf of Ob
66°34′N 072°27′E / 66.567°N 72.450°E / 66.567; 72.450 (13 Yamalo-Nenets Autonomous Okrug, Krasnoyarsk Krai, Sakha Republic & Chukotka Autonomous Okrug, Russia)  Russia Yamalo-Nenets Autonomous Okrug
Krasnoyarsk Krai
Sakha Republic
Chukotka Autonomous Okrug
66°34′N 171°01′W / 66.567°N 171.017°W / 66.567; -171.017 (14 Chukchi Sea, Arctic Ocean) Arctic Ocean Chukchi Sea
66°34′N 164°38′W / 66.567°N 164.633°W / 66.567; -164.633 (15 Seward Peninsula, Alaska, United States)  United States Alaska (Seward Peninsula)
66°34′N 163°44′W / 66.567°N 163.733°W / 66.567; -163.733 (18 Kotzebue Sound, Arctic Ocean) Arctic Ocean Kotzebue Sound
66°34′N 161°56′W / 66.567°N 161.933°W / 66.567; -161.933 (17 Selawik Lake, Alaska, United States)  United States Alaska – passing through Selawik Lake
66°34′N 141°00′W / 66.567°N 141.000°W / 66.567; -141.000 (18 Yukon, Northwest Territories & Nunavut, Canada)  Canada Yukon
Northwest Territories – passing through the Great Bear Lake
Nunavut
66°34′N 082°59′W / 66.567°N 82.983°W / 66.567; -82.983 (19 Foxe Basin, Hudson Bay) Hudson Bay Foxe Basin
66°34′N 073°25′W / 66.567°N 73.417°W / 66.567; -73.417 (20 Nettilling Lake, Baffin Island, Nunavut, Canada)  Canada Nunavut (Baffin Island – passing through Nettilling Lake)
66°34′N 061°24′W / 66.567°N 61.400°W / 66.567; -61.400 (21 Davis Strait, Atlantic Ocean) Atlantic Ocean Davis Strait
66°34′N 053°16′W / 66.567°N 53.267°W / 66.567; -53.267 (22 Greenland)  Greenland
66°34′N 034°09′W / 66.567°N 34.150°W / 66.567; -34.150 (23 Denmark Strait, Greenland Sea, Atlantic Ocean) Atlantic Ocean Denmark Strait
Greenland Sea
66°34′N 018°01′W / 66.567°N 18.017°W / 66.567; -18.017 (24 Grímsey, Iceland)  Iceland Island of Grímsey
66°34′N 017°59′W / 66.567°N 17.983°W / 66.567; -17.983 (25 Greenland Sea & Norwegian Sea, Atlantic Ocean) Atlantic Ocean Greenland Sea
Norwegian Sea
A sign along the Dalton Highway marking the location of the Arctic Circle in Alaska.
Arctic Circle line in Rovaniemi, Finland
Aurora Borealis above Arctic Circle sign in Yukon, Canada
A sign on the Vikingen island marking the Arctic Circle in Norway

See also

References