Arctic Circle

This article is about one of the five major circles of latitude. For other uses, see Arctic Circle (disambiguation).

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.

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, 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  Arctic Ocean Norwegian Sea 66°34′N 012°48′E Norway Nordland County 66°34′N 015°31′E Sweden Norrbotten County 66°34′N 023°51′E Finland Lapland Province 66°34′N 029°28′E Russia Republic of Karelia Murmansk Oblast Karelia again Murmansk again 66°34′N 033°25′E White Sea Kandalaksha Gulf 66°34′N 034°28′E Russia Murmansk Oblast – for about 7 km (4.3 mi) 66°34′N 034°38′E White Sea Kandalaksha Gulf 66°34′N 035°00′E Russia Murmansk Oblast (Kola Peninsula) 66°34′N 040°42′E White Sea 66°34′N 044°23′E Russia Nenets Autonomous Okrug Komi Republic Yamalo-Nenets Autonomous Okrug 66°34′N 071°05′E Gulf of Ob 66°34′N 072°27′E Russia Yamalo-Nenets Autonomous Okrug Krasnoyarsk Krai Sakha Republic Chukotka Autonomous Okrug 66°34′N 171°01′W Arctic Ocean Chukchi Sea 66°34′N 164°38′W United States Alaska (Seward Peninsula) 66°34′N 163°44′W Arctic Ocean Kotzebue Sound 66°34′N 161°56′W United States Alaska – passing through Selawik Lake 66°34′N 141°00′W Canada Yukon Northwest Territories – passing through the Great Bear Lake Nunavut 66°34′N 082°59′W Hudson Bay Foxe Basin 66°34′N 073°25′W Canada Nunavut (Baffin Island – passing through Nettilling Lake) 66°34′N 061°24′W Atlantic Ocean Davis Strait 66°34′N 053°16′W Greenland 66°34′N 034°09′W Atlantic Ocean Denmark Strait Greenland Sea 66°34′N 018°01′W Iceland Island of Grímsey 66°34′N 017°59′W 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

• Antarctic Circle
• Arctic haze
• Scott Polar Research Institute
• Territorial claims in the Arctic
• Tropic of Cancer
• Tropic of Capricorn

External links

• Terra Incognita: Exploration of the Canadian Arctic—Historical essay about early expeditions to the Canadian Arctic, illustrated with maps, photographs and drawings
• Temporal Epoch Calculations ©2006 by James Q. Jacobs Download: Epoch v2009.xls (modify D4)
• Useful constants" See: Obliquity of the ecliptic
• ArcticFocus Facts and news about Arctic