The Arctic Circle is a geographical term for The north frigid zone with The north temperate zone The boundary line. its latitude The value is 66°34' north latitude, and The intersection Angle of the yellow Complementary, most of which are The Arctic Ocean . The extent of the Arctic Circle includes Greenland , Nordic and Russia The north, and Canada North. There are many islands in the Arctic Circle, the largest of which is Greenland. Due to the cold, there are relatively few biological species in the Arctic Ocean, and the plants are mainly lichens, lichen Mainly, few trees, famous animals have Polar bear , seal , The whale Let's wait.

Chinese name: Arctic Circle
Foreign name: Arctic Circle
weft: 66°34 'north
vegetation: Mainly lichen and moss

Van Wai: Greenland, Northern Europe, Northern Russia and other regions
animal: Polar bears, seals, whales, etc
climate: Winters are long and cold, and summers are short and cool
Inclusive country: Russia, Canada, Greenland, etc

catalogue

Regional introduction

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Arctic Circle

The Arctic Circle, 66°34 'north latitude, is the southernmost boundary in the Northern Hemisphere where polar day and polar night occur. North of the Arctic Circle, the sun is slanted, the noon sun altitude Angle is very small, and there is a period of long night (polar night), and thus gain little solar heat, the northern cold zone. The Arctic Circle is the dividing line between the northern temperate zone and the northern cold zone.

The Arctic Circle is an imaginary circle at 66°34' north latitude, which is north Frigid zone The boundary with the north temperate zone, and the Angle of the equator (south The Tropic of Cancer Latitude values) are complementary. The area north of the Arctic Circle is called "inside the Arctic Circle." Usually, the area inside the Arctic Circle is called Arctic region , due to The Arctic Ocean And the surrounding land, the land portion of which includes Greenland , the Nordic countries, Northern Russia, America Alaska Northern and northern Canada. There are many islands in the Arctic Circle, the largest of which is Greenland . Because of the cold, there are few kinds of life in the Arctic Circle. plant lichen , lichen The main animals have Polar bear , seal , The whale Let's wait.

So is the Arctic Circle. Polar day Areas north of the Arctic Circle experience maximum daylight in summer and polar night in winter.

history

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majority historian It is believed that civilized human beings have turned their eyes to the Arctic since the earliest Ancient Greek It started. It is said that the Arctic Circle was first identified by the ancient Greeks. They found that the stars in the sky can be divided into two groups, one of which is in the northern part of the world and can be seen all year round. The other group is located near the zenith and further south, and they only cycle periodically with the seasons. The dividing line between the two sets of stars is defined by Ursa Major This circle is the circle of latitude 66°33' north, which is the Arctic Circle. In fact, Pythagoras (582-500 BC) and his school of thought despised the idea that the earth was square or rectangular. Their philosophical thinking led them to firmly believe that the earth was perfect only if it was spherical, in order to meet the needs of "universal harmony" and "number".

while Plato 's student Aristotle (384-322 BC) laid the foundation for the concept of "Earth." He even considered that in order to balance the large land masses of the Northern Hemisphere, the southern Hemisphere should also have a continent. Moreover, in order to avoid the earth's "top-heavy", resulting in the embarrassing situation of the big head (North Pole) facing down, the North Pole area should be a relatively light ocean. So, there's a guy called Pythias As early as more than 2,000 years ago, the Greeks bravely pulled up the sails and began the first impact on the Arctic in the history of civilized mankind. It took him about six years to complete the voyage, reaching as far north as Iceland or central Norway, possibly into the Arctic Circle. In 325 BC, Pythias returned to Marcelia (present-day Marseille, France).

1200 years after Pythias, an Old Norse nobleman named Otar made the first bypass in 870 AD Scandinavia Northernmost cape. Turn around Kola peninsula And into the White Sea. At about the same time as Ota, another Norse named Floki was sent to the northwest in search of new land, and found it Iceland .

while Greenland It was discovered by a Norwegian pirate named Eric the Red. He was deported after two consecutive killings in Iceland, which was already under Norwegian jurisdiction. With no other way to go, he had to pack his family and all their belongings into an uncovered boat and, with a sliver of hope, swam westward. After a rather difficult voyage, he finally came in sight of land. The climate is in the optimal climate phase of the global Little Warm Period (what Europeans call "Little Warm Period"). Medieval warm period "), making high-latitude regions like Greenland hospitable to life. Red Alec lived there for three years and thought it was a good place to live, so he decided to go back to Iceland to recruit immigrants. In order to make the place sound more attractive, he gave it a nice name, called Greenland, the green land. Summer along Greenland's southern coast is likely to be a verdant green indeed. Sure enough, waves of migrants came across the sea, carrying their possessions and livestock.

Since then, Greenland In its heyday, there were more than 280 settlements, thousands of people, 17 churches, not only established trade relations with Europe, the Pope even sent people to collect parish taxes. However, 500 years later, that is, around 1500 AD, with another fluctuation in the world's climate (into the Little Ice Age), the weather there became cold, so that this once prosperous paradise, gradually entered the state of silence. This period of human activity in the Arctic can be called a period of spontaneous regional discovery.

ASSETS

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Influenced by multi-stage and long-term tectonic changes, sedimentation and magmatic activity, various metal deposits (points) are scattered in the Arctic Circle and neighboring regions, including Sweden Kirina iron ore deposit The Norilsk nickel-Copper-platinum group element deposit and Tomtur niobium polymetallic deposit in Russia, the Komi Chromium deposit in Finland, the Isua Iron deposit and Fisknesset Chromium deposit in Greenland, the Mary River Iron deposit and Vois Bay nickel-copper-cobalt deposit in Canada, the Reed Dawg lead-zinc deposit in the United States and the Fortenox gold deposit in the United States are all world-renowned super-large deposits. Statistics show that in the past 10 years, the production of platinum group elements in the Arctic region accounted for more than 50% of the world's total, gem-grade and industrial-grade diamonds were 26% and 28%, nickel, cobalt and chromium were 22%, 21% and 15%, copper, iron and lead-zinc were 8%, 7% and 18%, gold and silver were 7% and 9%, respectively.

In addition, data show that the output of diamond, platinum group elements and nickel in the Russian Arctic Circle accounts for 99%, 98% and 80% of the total national production, respectively, chromium, manganese and gold are 90%, 90% and 40%. With the gradual warming of the climate and the expansion of the land area and the increase of prospecting and exploration efforts, the discovery and development of a large number of metal deposits will certainly greatly increase the annual output of mineral products in this region, and then inject new vitality into the development of the global economy and society. Therefore, it is expected that the international community has always paid great attention to the exploration, development and utilization of ore. ^[1]

Arctic Circle

United States Geological Survey According to the report, the recoverable oil reserves in the Arctic Circle are estimated to be 90 billion barrels, which can meet the world's oil demand for nearly three years. The Financial Times reported that the report is likely to intensify the battle for sovereignty in the Arctic, where Russia, the United States, Denmark, Norway and Canada have all said they have control.

In its first public report on Arctic resources, the Geological Survey said the region holds about 13% of the world's undiscovered oil reserves and 30% of the world's undiscovered natural gas reserves. Of this, the region's natural gas reserves are 47 trillion cubic meters. The US Geological Survey says the vast Arctic continental shelf may constitute the largest undiscovered area of remaining oil on Earth.

In 2007, Russia planted its flag on the seabed 4,000 meters below the North Pole, a move that immediately raised concerns about a scramble for Arctic mineral resources, especially oil and gas. Denmark in May in Greenland Ilulissat Hosted a summit of the five Arctic powers, trying to curb the rivalry and reasserting their commitment United Nations Convention on the Law of the Sea Administering the territorial sea.

At the same time, commercial interest in the Arctic is also gradually surging, Royal Dutch Shell and Anglo-Dutch energy groups have said they want to participate in the energy development of Russia's Yamal Peninsula region. In the United States, many companies are committed to the future development of the Alaska Arctic; On the Danish side, a number of major companies have expressed interest in participating in oil and gas exploration off the coast of Greenland.

Under the current law United Nations Convention on the Law of the Sea Since there is no evidence of any one country Continental shelf It extends to the North Pole, so the North Pole and its vicinity do not belong to any country, and the ice-covered Arctic Ocean around the North Pole is considered international waters.

However, the Arctic Circle Mineral resources Further confirmation of reserves is also worrying some environmentalists.

peculiarity

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The largest port city in the Arctic Circle: Port Narvik Norway's largest port city in the Arctic Circle, too Sweden , Finland North of the important estuary, in Norwegian sea On the southeastern shore of the Uft Fjord, this port city is home to more than 10,000 people.

A unique view of the Arctic Circle snow trees

The world's northernmost botanical garden: The Soviet Union in the Arctic Kara Peninsula Even in normal summer, there is a danger of blizzards or frost. However, the flowers and fruits there still grow very lush. Not far from the city of Kirovsk, there is the "Arctic - Alpine Botanical Garden", which is one of the largest botanical gardens in the former Soviet Union and the northernmost botanical garden in the world.

Arctic Circle airport: Kangerlussuaq, Greenland, 66 degrees 33 'N.

Countries in the Arctic Circle

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Within the Arctic Circle are the Arctic Ocean, islands, and land, which belong to eight countries: Russia , America , Canada , Denmark , Iceland , Norse , Sweden , Finland .

The coldest place in the Arctic: The average winter temperature in the Arctic is -20 Degree Celsius , many places -33 Degree Celsius The coldest point is 2,898 kilometers from the pole, near Omirenzhen, northeast of Siberia, at -53 degrees Celsius.

The northernmost city in the world: It is the capital of Svalbard, Norway Longyear . Longyear was originally an American name. In 1904 Longyear arrived in Svalbard and bought a coal mine on the island from the Norwegians. Two years later, when the Americans built the first house near the coal mine, the mine managers named the place Longyearbyen, after their boss. What was once a single house has now grown into a small town of 1,200 people, with a post office, schools, banks, hospitals, newspapers, restaurants, shopping malls, museums and so on. It's deep inside the Arctic Circle, at 78 degrees north latitude. At this latitude of the Earth, there is hardly any land left. It is a cold place where the sun is invisible for four months of the year, where snow and ice cover the land and darkness accompanies every hour. For the other four months, the sun hardly sets.

Climatic condition

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Arctic Circle

Due to the short sunshine in the Arctic Circle, the low height of the sun (the thickness of the atmosphere through which sunlight passes increases the amount of heat reflected and lost), and the reflection of sunlight by the surface ice sheet, the climate is cold all year round, and it is cold in winter and cool in summer. After the cold air enters the Arctic Circle, it cools and settles, forming the Arctic Polar high pressure zone .

Air flowing from the polar high pressure region to the lower latitudes due to Earth rotation deflection force The effect is always to the east, forming a northeast wind (blowing from northeast to southwest) in the Arctic Circle, called Polar easterly zone . Near the Arctic Circle, cold air carried by the easterly polar winds sinks downward, creating northeasterly winds near the surface, while warm air from the north at low latitudes meets cold polar air from the north, forming a front called a polar front.

The warm air, being lighter, climbs above the heavier southbound cold air, forming a subpolar updraft. The updraft is divided into two branches in the upper air, south and north. The southward branch sinks again at about 30° N, forming the mid-latitude circulation in the Northern Hemisphere. The one heading north is settling near the North Pole. Finished High latitude circulation circle .

Due to the subpolar updraft, the low air pressure near the Arctic Circle is called Subpolar low . But in Eurasia, in the winter Mongol-siberian High The impact was so strong that it spread across Eurasia and northern North America Subfrigid continental climate Subpolar depressions can only remain above the ocean.

vegetation

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Vegetation distribution

10℃ in the Arctic Circle and the Northern Hemisphere in July isotherm Roughly the same, while the latter is the same Arctic tree line Basically overlapping, so all three can be used as criteria to define the Arctic region. Near the Arctic Circle is Subcold coniferous forest zone ( The Taiga Belt ) and Arctic tundra In the transition zone between them, trees have struggled to grow as the soil freezes and the wind blows. From the south to the north, successive tracts of forest begin to disappear, replaced by a sparse arbor-shrub jumble of vegetation that eventually becomes a tundra landscape with only moss and lichen left.

Vegetation growth

On April 1, 2013, American Museum of Natural History , Cornell University and other researchers in the journal Natural climate variation Based on future global temperature trends, they built a set of models that predict vegetation changes in the Arctic Circle over the next few decades. The study predicts that nearly half of the species of surface vegetation in the Arctic will change in the coming decades, and the extent of green vegetation and tree cover will increase significantly. For example, in parts of Siberia, Tree line Will stretch north for hundreds of miles.

The researchers said that the change in vegetation will continue to affect the Arctic ecological environment, the Arctic surface covered by snow and ice, which reflects most of the sunlight, but the green vegetation can absorb much of the sunlight, and the increasing green vegetation could lead to further warming of the Arctic region.

Special phenomenon

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Polar day

Polar day Polar night (also known as perpetual day and perpetual night) is a phenomenon unique to the polar regions of the Earth, which means that there is either daylight (polar day) or darkness (polar night) for 24 hours a day. The Arctic Circle is The northern hemisphere The only thing that can happen Polar day The polar night. annual Gregorian calendar Around the 21st of March, which is Vernal equinox When the sun is directly over the equator. From this day on, the Arctic Circle began to appear in perpetual daylight. At first it was only north, Summer solstice The sun shines directly The Tropic of Cancer At this time, the Northern Hemisphere reaches the maximum range of maximum daylight, which is all the place north of the Arctic Circle. After that, the range of daylight gradually narrowed, to around September 23 Autumnal equinox Only points above the Arctic Circle have maximum daylight. After this day, the polar night begins, first at the point above the Arctic Circle, and then extends throughout the Arctic Circle. During the winter solstice around December 22, the sun is directly above the Tropic of Capricorn, and the entire area north of the Arctic Circle is polar night. Then the polar night range gradually shrank, and around March 21 of the following year, that is, the spring equinox, the polar night ended and the polar day began again.

Polar day

Somewhere inside the Arctic Circle, latitude The higher you go, the longer you have days and nights. Places near the North Pole spend nearly half the year in polar daylight and the other half in polar night. Within the circle, near the Arctic Circle, there are only a few days of polar day and night.

Inside the Arctic Circle, the sun never shines directly, and the sun is not high enough Summer solstice When it reaches its maximum height. At latitude alpha, Solar altitude Angle The maximum is 113°26' − α, less than 46°52'.

On August 5, 2018, temperatures in the Arctic Circle exceeded 30 ° C. ^[2]

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