Polar region

The polar regions of Earth, also known as Earth's frigid zones, are the regions of Earth surrounding its geographical poles (the North and South Poles). These regions are dominated by Earth's polar ice caps, the northern resting on the Arctic Ocean and the southern on the continent of Antarctica.

The Arctic has various definitions, including the region north of the Arctic Circle (currently Epoch 2010 at 66°33'44" N), or the region north of 60° north latitude, or the region from the North Pole south to the timberline. The Antarctic is usually defined as south of 60° south latitude, or the continent of Antarctica. The 1959 Antarctic Treaty uses the former definition.

The two polar regions are distinguished from the other two climatic and biomatic belts of Earth, a tropics belt near the equator, and two middle latitude regions located between the tropics and polar regions.

Polar regions receive less intense solar radiation than the other parts of Earth because the sun's energy arrives at an oblique angle, spreading over a larger area, and also travels a longer distance through the Earth's atmosphere in which it may be absorbed, scattered or reflected, which is the same thing that causes winters to be colder than the rest of the year in temperate areas.

The axial tilt of the Earth has a major effect on climate of the polar regions. Since the polar regions are the farthest from the equator, they receive the least amount of sunlight and are therefore frigid. The large amount of ice and snow also reflects a large part of what little sunlight the Polar regions receive, contributing to the cold. Polar regions are characterized by the polar climate, extremely cold temperatures, heavy glaciation wherever there is sufficient precipitation to form permanent ice, and extreme variations in daylight hours, with twenty-four hours of daylight in summer, and complete darkness at mid-winter.

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