The North Pole

From Wikipedia, the free encyclopedia

http://en.wikipedia.org/wiki/North_Pole

Location

An Azimuthal projection showing the Arctic Ocean and the North Pole.

North Pole scenery

The North Pole, also known as the Geographic North Pole or Terrestrial North Pole is defined as the point in the Northern Hemisphere where the Earth’s axis of rotation meets its surface. It should not be confused with the North Magnetic Pole.

The North Pole is the northernmost point on the Earth, lying diametrically opposite the South Pole. It defines geodetic latitude 90° North, as well as the direction of true north. At the North Pole all directions point south; all lines of longitude converge there, so its longitude can be defined as any degree value.

While the South Pole lies on a continental land mass, the North Pole is located in the middle of the Arctic Ocean amid waters that are almost permanently covered with constantly shifting sea ice. This makes it impractical to construct a permanent station at the North Pole (unlike the South Pole). However, the Soviet Union, and later Russia, constructed a number of manned drifting stations on a generally annual basis since 1937, some of which have passed over or very close to the Pole. Since 2002, the Russians have also annually established a base, Barneo, close to the Pole. This operates for a few weeks during early spring. Studies in the 2000s predicted that the North Pole may become seasonally ice-free due to Arctic ice shrinkage, with timescales varying from 2016 to the late 21st century or later.

The sea depth at the North Pole has been measured at 4,261 m (13,980 ft) by the Russian Mir submersible in 2007 and at 4,087 m (13,410 ft) by USS Nautilus in 1958. The nearest land is usually said to be Kaffeklubben Island, off the northern coast of Greenland about 700 km (430 mi) away, though some perhaps non-permanent gravel banks lie slightly closer. The nearest permanently inhabited place is Alert in the Qikiqtaaluk Region, Nunavut, Canada, which is located 817 km (508 mi) from the Pole.

Day and night

The sun at the North Pole is continuously above the horizon during the summer and continuously below the horizon during the winter. Sunrise is just before the March equinox (around March 20); the sun then takes three months to reach its highest point of near 23½° elevation at the summer solstice (around June 21), after which time it begins to sink, reaching sunset just after the September equinox (around September 23). When the sun is visible in the polar sky, it appears to move in a horizontal circle above the horizon. This circle gradually rises from near the horizon just after the vernal equinox to its maximum elevation (in degrees) above the horizon at summer solstice and then sinks back toward the horizon before sinking below it at the autumnal equinox.

A civil twilight period of about two weeks occurs before sunrise and after sunset, a nautical twilight period of about five weeks occurs before sunrise and after sunset and an astronomical twilight period of about seven weeks occurs before sunrise and after sunset.

These effects are caused by a combination of the Earth’s axial tilt and its revolution around the sun. The direction of the Earth’s axial tilt, as well as its angle relative to the plane of the Earth’s orbit around the sun, remains very nearly constant over the course of a year (both change very slowly over long time periods). At northern midsummer the North Pole is facing towards the sun to its maximum extent. As the year progresses and the Earth moves around the sun, the North Pole gradually turns away from the sun until at midwinter it is facing away from the Sun to its maximum extent. A similar sequence is observed at the South Pole, with a six-month time difference.

Time

In most places on Earth, local time is determined by longitude, such that the time of day is more-or-less synchronised to the position of the sun in the sky (for example, at midday the sun is roughly at its highest). This line of reasoning fails at the North Pole, where the sun rises and sets only once per year, and all lines of longitude, and hence all time zones, converge. There is no permanent human presence at the North Pole and no particular time zone has been assigned. Polar expeditions may use any time zone that is convenient, such as Greenwich Mean Time, or the time zone of the country from which they departed.

Climate

Arctic ice shrinkages of 2007 compared to 2005 and also compared to the 1979–2000 average.

The North Pole is substantially warmer than the South Pole because it lies at sea level in the middle of an ocean (which acts as a reservoir of heat), rather than at altitude in a continental land mass.

Winter (January) temperatures at the North Pole can range from about −43 °C (−45 °F) to −26 °C (−15 °F), perhaps averaging around −34 °C (−29 °F). Summer temperatures (June, July and August) average around the freezing point (0 °C (32 °F)). The highest temperature yet recorded is 5 °C (41 °F), much warmer than the South Pole’s record high of only −12.3 °C (9.9 °F).

The sea ice at the North Pole is typically around 2 to 3 m (6 ft 7 in to 9 ft 10 in) thick, although ice thickness, its spatial extent, and the fraction of open water within the ice pack can vary rapidly and profoundly in response to weather and climate. Studies have shown that the average ice thickness has decreased in recent years. It is likely that global warming has contributed to this, but it is not possible to attribute the recent abrupt decrease in thickness entirely to the observed warming in the Arctic. Reports have also predicted that within a few decades the Arctic Ocean will be entirely free of ice in the summer.  This may have significant commercial implications.

The retreat of the Arctic sea ice will accelerate global warming, as less ice cover reflects less solar radiation, and may have serious climate implications by contributing to Arctic cyclone generation.

Flora and fauna

Polar bears are believed rarely to travel beyond about 82° North owing to the scarcity of food, though tracks have been seen in the vicinity of the North Pole, and a 2006 expedition reported sighting a polar bear just 1 mi (1.6 km) from the Pole. The ringed seal has also been seen at the Pole, and Arctic foxes have been observed less than 60 km (37 mi) away at 89°40′ N.

Birds seen at or very near the Pole include the Snow Bunting, Northern Fulmar and Black-legged Kittiwake, though some bird sightings may be distorted by the tendency of birds to follow ships and expeditions.

Fish have been seen in the waters at the North Pole, but these are probably few in number. A member of the Russian team that descended to the North Pole seabed in August 2007 reported seeing no sea creatures living there. However, it was later reported that a sea anemone had been scooped up from the seabed mud by the Russian team and that video footage from the dive showed unidentified shrimps and amphipods.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s