Arctic

The Arctic

The Arctic

The Arctic consists of ocean surrounded by continental land masses and islands. The central Arctic Ocean is ice-covered year-round, and snow and ice are present on land for most of the year.

The southern limit of the arctic region is commonly placed at the Arctic Circle (latitude 66 degrees, 32 minutes North). The Arctic Circle is an imaginary line that marks the latitude above which the sun does not set on the day of the summer solstice (usually 21 June) and does not rise on the the day of the winter solstice (usually 21 December). North of this latitude, periods of continuous daylight or night last up to six months at the North Pole.

This region of the planet, north of the Arctic Circle, includes the Arctic Ocean, Greenland, Baffin Island, other smaller northern islands, and the far northern parts of Europe, Russia (Siberia), Alaska and Canada.

The Arctic People Plants Animals

The Arctic is a vast, ice-covered ocean, surrounded by tree-less, frozen ground, that teems with life, including organisms living in the ice, fish and marine mammals, birds, land animals and human societies.

The Arctic Map

NSIDC Map

The Arctic consists of the Arctic Ocean, bordered by the northern parts of the mainlands of North American and Eurasia, and their outlying islands. Some of these islands are mountainous with interior icecaps, such as Greenland and the northern half of Novaya Zemlaya. Others are low-lying and not glaciated, such as Wrangel Island and the western islands of the Canadian Arctic.

Topography and Bathymetry

The Arctic Circle is an imaginary line located at 66º, 30'N latitude, and as a guide defines the southernmost part of the Arctic. The climate within the Circle is very cold and much of the area is always covered with ice.

In the mid winter months, the sun never rises and temperatures can easily reach lows of - 50º F in the higher latitudes. In the summer months (further south), 24 hours of sunlight a day melts the seas and topsoil, and is the main cause of icebergs breaking off from the frozen north and floating south, causing havoc in the shipping lanes of the north Atlantic.

The total number of species as well as biological productivity is lower than in more southern latitudes. Strong surface winds occur resulting in a severe wind-chill, and abundant drifting snow in winter. Instead of tree growth there is tundra vegetation that includes grasses, sedges, mosses, lichens, and shrubs...all low-standing plants that exist on permafrost soils that are frozen solid throughout most of the year.

In terms of marine life, because the waters of the Arctic are permanently covered with a layer of drifting pack ice, sunlight never deeply penetrates the surface waters to nourish and encourage biological growth. In addition, the water is vertically stable, offering no upwelling of inorganic salts (like phosphates, nitrates, and silicates,) without which a rich life in the upper sunlit layers cannot exist. The result is that the true marine Arctic remains cold and relatively lifeless. It is only near the land or in the Subarctic where the pack-ice is seasonal and the waters are warmer and richer in nutrients, that there is a proliferation of plant and animal life that encompasses the total spectrum of the food chain from microscopic phytoplankton to walruses and whales.

Siberia feels the heat of global warming Russia Today Video

The primary residents of the Arctic include the Eskimos (Inuits), Lapps and Russians with an overall population (of all peoples) exceeding two million. The indigenous Eskimos have lived in the area for over 9,000 years, and many have now given up much of their traditional hunting and fishing to work in the oil fields and the varied support villages. Some contemporary occupants of the Arctic and the areas they inhabit are shown on the map below.

The Arctic Population Map

The first explorers of the Arctic were Vikings. Norwegians visited the northern regions in the 9th century, and Eric the Red (Icelander) established a settlement in Greenland in 982.

Robert E. Peary

The northernmost point on the earth's surface is the geographic North Pole, also known as true north. It's located at 90° North latitude and all lines of longitude converge at the pole. The earth's axis connects the north and south poles, as its the line around which the earth rotates. The North Pole is about 450 miles (725 km) north of Greenland in the middle of the Arctic Ocean - the sea there has a depth of 13,410 feet (4087 meters). In 1909, after numerous attempts by regional explorers, Robert E. Peary reached the North Pole.

Magnetic North Pole

A magnetic compass does not point toward the true North Pole of the Earth. Rather, it more closely points toward the North Magnetic Pole of the Earth. The North Magnetic Pole is currently located in northern Canada. It wanders in an elliptical path each day, and moves, on the average, more than forty meters northward each day. Evidence indicates that the North Magnetic Pole has wandered over much of the Earth's surface in the 4.5 billion years since the Earth formed. The Earth's magnetic field is created by Earth's partially ionized outer core, which rotates more rapidly than the Earth's surface.

NASA JPL, University of Alaska - Fairbanks Satellite: RADARSAT

Arctic Climate

The arctic climate is characterized by high spatial variability, and includes both polar maritime (influenced by the ocean) and continental (influenced by large land masses) climate subtypes. The main constant is that the climate in all arctic areas is affected by the extreme solar radiation conditions of high latitudes.

For example, the amount of solar radiation received in summer along the Siberian arctic coast compares favorably, by virtue of the long period of daylight, with that in lower middle latitudes. However, the low sun angle (elevation of the sun above the horizon) means that even minor topographic features, such as low hills, can cause major differences in climate at the local level by shading. Even though the Arctic receives a large amount of solar energy in summer, the high reflectivity (albedo) of snow and ice surfaces keeps absorption of solar energy low. Therefore, the heat gained during the long summer days is small and highly dependent on surface properties such as topography and albedo. For instance, wet tundra and bare ground (with low albedo) absorb more solar radiation than do high-albedo ice sheets. Similarly, wet snow absorbs more radiation than dry snow. Solar radiation is small or absent in winter.

Arctic Air Temperature

The annual cycle of global radiation (brown line) and surface air temperature (blue line) at a grid cell location in the central Beaufort Sea. Values were drawn from the Arctic Meteorology and Climate Atlas grided fields for global radiation and two-meter air temperature.

Maritime climate conditions prevail over the Arctic Ocean, coastal Alaska, Iceland, northern Norway and adjoining parts of Russia. In these areas, winters are cold and stormy. Summers are cloudy but mild with mean temperatures about 10 degrees Celsius. Annual precipitation is generally between 60 cm and 125 cm, with a cool season maximum (largely snowfall) and about six months of snow cover.

The interior, continental climates have much more severe winters, although precipitation amounts are less. In these regions, permafrost (permanently frozen ground) is wide-spread and often of great depth. In summer, only the top one to two meters of ground thaw. Since the water cannot readily drain away, this "active layer" often remains waterlogged. Although frost may occur in any month, long summer days usually provide three months with mean temperatures above 10 degrees Celsius, and at some stations in the continental interiors temperatures can exceed 30 degrees Celsius.

In winter, arctic weather is dominated by the frequent occurrence of inversions (when warm air lies above a colder air layer near the surface). The inversion layer decouples the surface wind from the stronger upper layer wind. For this reason, surface wind speeds tend to be lower in winter than one might expect. In summer, inversions are less frequent and weaker, and arctic weather patterns are dominated by the movement of low pressure systems (cyclones) across Siberia and into the Arctic Basin.

In many arctic and subarctic regions, the weather is controlled by semipermanent low pressure systems that are weakly developed in summer, but stronger in winter. The most important of these low pressure systems are the Icelandic Low and the Aleutian Low. In winter, eastern Eurasia is dominated by the semipermanent Siberian High. High pressure is also prevalent over the Canadian Arctic Archipelago during the cold season.

Arctic Mid-Ocean Ridge Graphic

Arctic Mid-Ocean Ridge Expedition Graphic

Arctic Tundra

Vegetation of the circumpolar Arctic . The southern boundary of Arctic vegetation is the treeline. This map gives a good impression of just how closely tied the tundra biome is to the ocean; 61% of lowland tundra is within 50 km of sea ice, 80% is within 100 km, and 100% is within 350 km.

Arctic Report Card 2011

Sea ice and ocean observations over the past decade (2001-2011) suggest that the Arctic Ocean climate has reached a new state, with characteristics different than those observed previously. The new ocean climate has less sea ice (both thickness and summer extent) and, as a result, a warmer and fresher upper ocean. A clockwise ocean circulation regime has dominated the Arctic Ocean for at least 14 years (1997-2011), in contrast to the typical duration of a 5-8 year pattern of circulation shifts observed from 1948-1996. In the Bering Sea, aragonite undersaturation, i.e., ocean acidification, throughout the water column is causing seasonal calcium carbonate mineral suppression in some areas.

The September 2011 Arctic sea ice extent was the second lowest of the past 30 years. The five lowest September ice extents having occurred in the past five years, suggesting that a shift to a new sea ice state continues. The amount of older, thicker multiyear ice continues to decrease and both the Northern Sea Route and the Northwest Passage were ice-free in September.

Observations of the Arctic marine ecosystems provide a glimpse of what can only be described as profound and continuing changes. For example, primary production by phytoplankton in the Arctic Ocean increased ~20% between 1998 and 2009, mainly as a result of increasing open water extent and duration of the open water season. Changes in Arctic Ocean bottom communities include shifts in composition, geographical ranges, and biomass. While polar bears and walrus are experiencing negative impacts due to loss of habitat, whales now have greater access to the Northwest Passage and other northern feeding areas.

There is a direct link between increases and earlier peaks in Arctic tundra vegetation in many parts of the Arctic and increasing duration of the open water season due to decreasing summer sea ice extent. Vegetation productivity ranged from a 26% increase adjacent to the Beaufort Sea to a small decline in several areas. On the North Slope of Alaska, immediately south of the Beaufort Sea, new record high temperatures at 20 m depth were recorded at all permafrost observatories, where measurements began in the late 1970s. River discharge into the Arctic Ocean during 2010 was close to the long-term mean. Despite changes in tundra biomass, migratory barren-ground caribou appear to be within known ranges of natural variation.

In 2011 there was continued widespread warming in the Arctic, where deviations from historical air temperatures are amplified by a factor of two or more relative to lower latitudes. This phenomenon, called Arctic Amplification, is primarily a consequence of increased summer sea ice loss and northward transport of heat by the atmosphere and ocean. December 2010 to January 2011, and summer 2011, repeated the shift in wind patterns observed in December 2009 and February 2010 that resulted in relatively warm Arctic temperatures and severe cold weather in eastern North America, northern Europe and eastern Asia. Related to these shifts, the western slope of the Greenland ice sheet in particular experienced an increase in surface melting in summer 2011, amplified by albedo feedback and below-normal summer snowfall. Satellite gravity measurements show that the mass loss from the entire Greenland ice sheet during 2010-2011 was the largest annual loss in the satellite record of 2002-present. Lake ice cover duration, largely influenced by air temperature changes, was shorter by as much as 4-5 weeks in 2010-2011 compared to the 1997-2010 average in the eastern Canadian Arctic.

Introduction Arctic Ocean

Background:
The Arctic Ocean is the smallest of the world's five oceans (after the Pacific Ocean, Atlantic Ocean, Indian Ocean, and the recently delimited Southern Ocean). The Northwest Passage (US and Canada) and Northern Sea Route (Norway and Russia) are two important seasonal waterways. A sparse network of air, ocean, river, and land routes circumscribes the Arctic Ocean.

Geography Arctic Ocean

Location:
body of water between Europe, Asia, and North America, mostly north of the Arctic Circle

Geographic coordinates:
90 00 N, 0 00 E

Map references:
Arctic Region

Area:
total: 14.056 million sq km
note: includes Baffin Bay, Barents Sea, Beaufort Sea, Chukchi Sea, East Siberian Sea, Greenland Sea, Hudson Bay, Hudson Strait, Kara Sea, Laptev Sea, Northwest Passage, and other tributary water bodies

Area - comparative:
slightly less than 1.5 times the size of the US

Coastline:
45,389 km

Climate:
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

Terrain:
central surface covered by a perennial drifting polar icepack that, on average, is about 3 meters thick, although pressure ridges may be three times that thickness; 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 (highest percentage of any ocean) with the remainder a central basin interrupted by three submarine ridges (Alpha Cordillera, Nansen Cordillera, and Lomonosov Ridge)

Elevation extremes:
lowest point: Fram Basin -4,665 m
highest point: sea level 0 m

Natural resources:
sand and gravel aggregates, placer deposits, polymetallic nodules, oil and gas fields, fish, marine mammals (seals and whales)

Natural hazards:
ice islands occasionally break away from northern Ellesmere Island; icebergs calved from glaciers in western Greenland and extreme northeastern Canada; permafrost in 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

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

Economy Arctic Ocean

Economy - overview:
Economic activity is limited to the exploitation of natural resources, including petroleum, natural gas, fish, and seals.

Transportation Arctic Ocean

Ports and terminals:
Churchill (Canada), Murmansk (Russia), Prudhoe Bay (US)

Transportation - note:
sparse network of air, ocean, river, and land routes; the Northwest Passage (North America) and Northern Sea Route (Eurasia) are important seasonal waterways

Transnational Issues Arctic Ocean

Disputes - international:
the littoral states are engaged in various stages of demonstrating the limits of their continental shelves beyond 200 nautical miles from their declared baselines in accordance with Article 76, paragraph 8, of the United Nations Convention on the Law of the Sea; record summer melting of sea ice in the Arctic has restimulated interest in maritime shipping lanes and sea floor exploration

Credit: NOAA, NASA, UNEP, NSIDC, CIA Factbook