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Northern Hemisphere

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This article is about the Hemisphere of Earth. For astronomical observations of the sky, seeNorthern celestial hemisphere.
Northern Hemisphere shaded blue. The hemispheres appear unequal here becauseAntarcticais not shown.
Northern Hemisphere from above theNorth Pole

TheNorthern Hemisphereis the half ofEarththat isnorthof theEquator.For other planets in theSolar System,north is defined as being in the samecelestial hemisphererelative to theinvariable planeof the Solar System as Earth'sNorth Pole.[1]

Due to Earth'saxial tiltof 23.439281°,winterin the Northern Hemisphere lasts from theDecember solstice(typically December 21UTC) to theMarch equinox(typically March 20 UTC), whilesummerlasts from theJune solsticethrough to theSeptember equinox(typically on 23 September UTC). The dates vary each year due to the difference between thecalendar yearand theastronomical year.Within the Northern Hemisphere, oceanic currents can change the weather patterns that affect many factors within the north coast. Such events includeEl Niño–Southern Oscillation.

Trade windsblow from east to west just above the equator. The winds pull surface water with them, creating currents, which flow westward due to theCoriolis effect.The currents then bend to the right, heading north. At about 30 degrees north latitude, a different set of winds, thewesterlies,push the currents back to the east, producing a closed clockwise loop.[2]

Its surface is 60.7% water, compared with 80.9% water in the case of theSouthern Hemisphere,and it contains 67.3% of Earth's land.[3]The continents ofNorth Americaand mainlandEurasiaare located entirely in the Northern Hemisphere, together with about two-thirds ofAfricaand a small part ofSouth America.

Geography and climate[edit]

During the 2.5 million years of thePleistocene,numerous cold phases calledglacials(Quaternary ice age), or significant advances of continental ice sheets, inEuropeandNorth America,occurred at intervals of approximately 40,000 to 100,000 years. The long glacial periods were separated by more temperate and shorterinterglacialswhich lasted about 10,000–15,000 years. The last cold episode of thelast glacial periodended about 10,000 years ago.[4]Earth is currently in an interglacial period ofthe Quaternary,called theHolocene.[5]The glaciations that occurred during the glacial period covered many areas of the Northern Hemisphere.

Northern hemisphere glaciation during the lastice ages.The setup of 3 to 4 kilometer thick ice sheets caused asea level loweringof about 120 m.

TheArcticis a region around theNorth Pole(90°latitude). Its climate is characterized by cold winters and cool summers. Precipitation mostly comes in the form of snow. Areas inside theArctic Circle(66°34′ latitude) experience some days in summer when the Sun never sets, and some days during the winter when it never rises. The duration of these phases varies from one day for locations right on the Arctic Circle to several months near the Pole, which is the middle of the Northern Hemisphere. Between the Arctic Circle and theTropic of Cancer(23°26′ latitude) lies theNorthern temperate zone.The changes in these regions between summer and winter are generally mild, rather than extreme hot or cold. However, a temperate climate can have very unpredictable weather.

Tropicalregions (between the Tropic of Cancer and the Equator, 0° latitude) are generally hot all year round and tend to experience arainy seasonduring the summer months, and adry seasonduring the winter months.

Canadian Rockiesin North America

In the Northern Hemisphere, objects moving across or above the surface of the Earth tend to turn to the right because of theCoriolis effect.As a result, large-scale horizontal flows of air or water tend to form clockwise-turninggyres.[6]These are best seen in ocean circulation patterns in theNorth AtlanticandNorth Pacificoceans.[6]Within the Northern Hemisphere, oceanic currents can change the weather patterns that affect many factors within the north coast.[7]For the same reason, flows of air down toward the northern surface of the Earth tend to spread across the surface in a clockwise pattern. Thus, clockwise air circulation is characteristic ofhigh pressureweather cells in the Northern Hemisphere. Conversely, air rising from the northern surface of the Earth (creating a region of low pressure) tends to draw air toward it in a counterclockwise pattern.Hurricanesandtropical storms(massive low-pressure systems) spin counterclockwise in the Northern Hemisphere.[8]

The shadow of a sundial moves clockwise on latitudes north of thesubsolar pointand anticlockwise to the south. During the day at these latitudes, the Sun tends to rise to its maximum at a southerly position. Between the Tropic of Cancer and the Equator, the sun can be seen to the north, directly overhead, or to the south at noon, depending on the time of year. In the Southern Hemisphere, the midday Sun is predominantly in the north.

When viewed from the Northern Hemisphere, theMoonappears inverted compared to a view from the Southern Hemisphere.[9][10]The North Pole faces away from theGalactic Centerof theMilky Way.This results in the Milky Way being sparser and dimmer in the Northern Hemisphere compared to the Southern Hemisphere, making the Northern Hemisphere more suitable for deep-space observation, as it is not "blinded" by the Milky Way.[citation needed]

Demographics[edit]

As of 2015, the Northern Hemisphere is home to approximately 6.4 billion people which is around 87.0% of the earth's total human population of 7.3 billion people.[11][12][13]

List of continents, countries or territories, and oceans in the Northern Hemisphere[edit]

Continents
Africa Asia Americas Europe
about two-thirds, from north ofLibrevilleinGabonin the west to south ofMogadishuinSomaliain the east. the entire continental mainland. Part ofIndonesia,and24 out of 26 atollsofMaldivesin theIndian Ocean,are also in the Northern Hemisphere. all ofNorth America,Central America,and theCaribbeanislands. About one-fifth ofSouth America,from north ofQuitoinEcuadorin the west to north of theAmazon Rivermouth inBrazilin the east. entirely in the Northern Hemisphere[note 1]
Countries or Territories
Africa Asia Americas Europe[note 1]
Entirely
Mostly
Partly
Entirely
Mostly
Partly
Entirely
Mostly
Partly
Entirely
Mostly
Ocean
Arctic Atlantic Indian Pacific
Entirely
Entirely
Mostly
Entirely
Mostly
Entirely
Mostly
Partly

See also[edit]

Notes[edit]

  1. ^abThe continent itself is entirely within the Northern Hemisphere. However, some overseas territories of the countries ofFrance,Norwayand theUnited Kingdomare in the Southern Hemisphere.

References[edit]

  1. ^Archinal, Brent A.; A'Hearn, Michael F.; Bowell, Edward G.; Conrad, Albert R.; Consolmagno, Guy J.; et al. (2010)."Report of the IAU Working Group on Cartographic Coordinates and Rotational Elements: 2009"(PDF).Celestial Mechanics and Dynamical Astronomy.109(2): 101–135.Bibcode:2011CeMDA.109..101A.doi:10.1007/s10569-010-9320-4.S2CID189842666.Archived fromthe original(PDF)on 2016-03-04.Retrieved2018-09-26.
  2. ^"Ocean Currents".National Geographic Society.2019-07-01.Archivedfrom the original on 2021-11-20.Retrieved2020-10-16.
  3. ^Life on Earth: A – G.. 1.ABC-CLIO.2002. p. 528.ISBN9781576072868.Archivedfrom the original on 22 January 2023.Retrieved8 September2016.
  4. ^"Quaternary Period".National Geographic.2017-01-06. Archived fromthe originalon 2020-11-29.Retrieved2022-05-06.
  5. ^"How long can we expect the present Interglacial period to last?".U.S. Department of the Interior.Archivedfrom the original on 2022-07-26.Retrieved2022-05-06.
  6. ^abUS Department of Commerce, National Oceanic and Atmospheric Administration."Boundary Currents – Currents: NOAA's National Ocean Service Education".oceanservice.noaa.gov.Archivedfrom the original on 2010-05-15.Retrieved2020-07-31.
  7. ^"How does the ocean affect climate and weather on land?".NOAA Ocean Exploration.U.S. Department of Commerce.Retrieved21 November2023.
  8. ^"Hurricanes: Science and Society: Primary Circulation".hurricanescience.org.Archivedfrom the original on 2010-12-28.Retrieved2021-08-11.
  9. ^Laura Spitler."Does the Moon look different in the northern and southern hemispheres? (Beginner) – Curious About Astronomy? Ask an Astronomer".cornell.edu.Archivedfrom the original on 4 November 2015.Retrieved10 November2015.
  10. ^"Perspective of the Moon from the Northern and Southern Hemispheres".Archived fromthe originalon 9 September 2017.Retrieved22 October2013.
  11. ^Calculated from World Population Yearbook 2019(in thousands) World total population: 7,359,970 Northern Hemisphere population: 6,405,030 87.0% Southern Hemisphere population: 954,940 13.0% Note 1) If there is no data for 2019, the latest data was used. Note 2) Countries with land that straddles the equator are divided into half populations in each of the Northern and Southern Hemispheres.
  12. ^"90% Of People Live In The Northern Hemisphere – Business Insider".Business Insider.4 May 2012.Archivedfrom the original on 19 January 2018.Retrieved10 November2015.
  13. ^"GIC – Article".galegroup.Archivedfrom the original on 18 April 2016.Retrieved10 November2015.
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