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Northern Hemisphere

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The Northern Hemisphere is the half of Earth located north of the equator.

Hemisferio Norte
Hemisferio Norte

This region is defined by its position relative to the equator and the Earth's axial tilt. For other planets in our Solar System, the term "north" refers to the celestial hemisphere relative to the invariable plane of the Solar System. The Northern Hemisphere is a massive part of our planet. It contains 67.3% of Earth's total land area. This is significantly more than the Southern Hemisphere, which is 80.9% water.

Northern Hemisphere LamAz
Northern Hemisphere LamAz

Because of this land distribution, most of the world's continents are located here.

Climate and seasons in this hemisphere are driven by the Earth's axial tilt. The Earth tilts at an angle of 23.439281 degrees. This tilt causes seasonal variations in day and night lengths. It also causes changes in temperature throughout the year. Winter is conventionally defined from the December solstice to the March equinox. Summer is the period from the June solstice to the September equinox. These dates change slightly each year due to the difference between the calendar and astronomical years. The temperature changes often lag behind the changes in day and night length.

Different zones within the hemisphere experience very different environments. The Arctic is the region around the North Pole at 90 degrees latitude. It features cold winters and cool summers with much precipitation as snow. Inside the Arctic Circle, at 66°34′ latitude, the Sun may never set in summer or never rise in winter. Between the Arctic Circle and the Tropic of Cancer (23°26′ latitude) lies the Northern temperate zone. This area has generally mild seasonal changes, though weather can be unpredictable.

Snow covered mountains in Mount Robson (Unsplash)
Snow covered mountains in Mount Robson (Unsplash)

Tropical regions exist between the Tropic of Cancer and the Equator. These areas are hot all year and have rainy and dry seasons.

Movement in the Northern Hemisphere is influenced by the Coriolis effect. This effect causes objects moving across or above the surface to turn to the right. This force creates large-scale clockwise-turning gyres in ocean circulation. You can see these patterns in the North Atlantic and North Pacific oceans. Trade winds blow from east to west just above the equator. They pull surface water westward, creating currents that eventually bend right and head north. At 30 degrees north latitude, the westerlies push these currents back east. This creates a closed, clockwise loop of water.

Atmospheric pressure also follows these patterns due to the Coriolis effect. High-pressure weather cells feature clockwise air circulation. Conversely, air rising from the surface creates a low-pressure region. This rising air draws other air inward in a counterclockwise pattern. Because of this, hurricanes and tropical storms spin counterclockwise in the Northern Hemisphere. These massive low-pressure systems are powerful drivers of weather. Oceanic currents also change weather patterns for many coastal areas. Events like the El Niño–Southern Oscillation can impact these northern coasts.

History shows that the Northern Hemisphere has undergone massive climate shifts. During the Pleistocene, which lasted 2.5 million years, the region experienced many cold phases. These are known as glacials or the Quaternary ice age. These phases involved significant advances of continental ice sheets in Europe and North America.

Northern icesheet hg
Northern icesheet hg

Glacials occurred at intervals of 40,000 to 100,000 years. They were separated by shorter, warmer interglacials lasting 10,000 to 15,000 years. These ice sheets were 3 to 4 kilometers thick. They were so heavy they lowered sea levels by about 120 meters. The last major cold episode ended about 10,000 years ago. We are currently in an interglacial period called the Holocene.

Human life is heavily concentrated in this hemisphere. As of 2015, the Northern Hemisphere was home to approximately 6.4 billion people. This represents about 87.0% of the Earth's total human population of 7.3 billion. The hemisphere includes all of North America and the mainland of Eurasia. It also contains about two-thirds of Africa and a small part of South America. Looking at the sky, the North Pole faces away from the Galactic Center of the Milky Way. This makes the Milky Way appear sparser and dimmer here. This characteristic makes the Northern Hemisphere excellent for deep-space observation.

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🖼️ Images & Media (4)
File:Hemisferio Norte.png
Hemisferio Norte.png
File:Northern Hemisphere LamAz.png
Northern Hemisphere LamAz.png
File:Northern icesheet hg.png
Northern icesheet hg.png
File:Snow covered mountains in Mount Robson (Unsplash).jpg
Snow covered mountains in Mount Robson...
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