Editing Jet stream (section)

== Uses ==

The northern polar jet stream is the most important one for aviation and weather forecasting, as it is much stronger and at a much lower altitude than the subtropical jet streams and also covers many countries in the northern hemisphere,<ref name="Osborne 2020"/> while the southern polar jet stream mostly circles [[Antarctica]] and sometimes the southern tip of [[South America]].<ref>{{cite web |title=The Polar Jet Stream and Polar Vortex |url=https://climate.mit.edu/explainers/polar-jet-stream-and-polar-vortex |website=MIT Climate Portal |date=21 May 2024 |access-date=2 December 2024}}</ref>

=== Aviation ===

[[File:Greatcircle Jetstream routes.svg|thumb|250px|Flights between [[Tokyo]] and [[Los Angeles, California|Los Angeles]] using the jet stream eastbound and a [[great circle]] route westbound.]]

The location of the jet stream is important for aviation. Aircraft flight time can be dramatically affected by either flying with the flow or against it. Often, airlines work to fly with the jet stream to obtain significant fuel cost and time savings.<ref name="Osborne 2020">{{cite news |last=Osborne |first=Tony |title=Strong Jet Streams Prompt Record Breaking Transatlantic Crossings |publisher=Aviation Week|date= 10 February 2020 |url=https://aviationweek.com/air-transport/strong-jet-streams-prompt-record-breaking-transatlantic-crossings |archive-url=https://web.archive.org/web/20200211165218/https://aviationweek.com/air-transport/strong-jet-streams-prompt-record-breaking-transatlantic-crossings |archive-date= 11 February 2020 |access-date=11 February 2020 |url-status=live}}</ref><ref>Ned Rozell. [http://www.gi.alaska.edu/ScienceForum/ASF17/1727.html Amazing flying machines allow time travel.] {{Webarchive |url=https://web.archive.org/web/20080605031147/http://www.gi.alaska.edu/ScienceForum/ASF17/1727.html |date=5 June 2008 }} Retrieved on 8 May 2008.</ref>

Commercial use of the jet stream began on 18 November 1952, when [[Pan Am]] flew from Tokyo to Honolulu at an altitude of {{convert|7600|m|ft}}. It cut the trip time by over one-third, from 18 to 11.5 hours.<ref>{{cite journal |last=Taylor |first=Frank J. |title=The Jet Stream Is The Villain |journal=Popular Mechanics |year=1958 |pages=97 |url=https://books.google.com/books?id=5d0DAAAAMBAJ&q=1952+tokyo+honolulu&pg=PA96 |access-date=13 December 2010}}</ref>

Within North America, the time needed to fly east across the continent can be decreased by about 30 minutes if an airplane can fly with the jet stream.<ref>{{cite news |title=Flying east from Dallas-Fort Worth? Strong jet-stream winds could get you there early |url=https://www.dallasnews.com/news/weather/2019/02/21/flying-east-from-dallas-fort-worth-strong-jet-stream-winds-could-get-you-there-early/ |last=Jimenez |first=Jesus |date=21 February 2019 |publisher=The Dallas Morning News |access-date=2 December 2024}}</ref> Across the [[Atlantic Ocean]] the [[North Atlantic Tracks]] service allows airlines and [[air traffic control]] to accommodate the jet stream for the benefit for airlines and other users.<ref>{{cite web |title=North Atlantic Operations - Organised Track System |url=https://skybrary.aero/articles/north-atlantic-operations-organised-track-system |publisher=SKYbrary Aviation Safety |access-date=2 December 2024}}</ref>

Associated with jet streams is a phenomenon known as [[clear-air turbulence]] (CAT), caused by vertical and horizontal [[wind shear]] caused by jet streams.<ref>[[BBC]]. [http://www.bbc.co.uk/weather/features/understanding/jetstreams_uk.shtml Jet Streams in the UK.] {{webarchive |url=https://web.archive.org/web/20080118235955/http://www.bbc.co.uk/weather/features/understanding/jetstreams_uk.shtml |date=18 January 2008 }} Retrieved on 8 May 2008.</ref> The CAT is strongest on the cold [[air]] side of the jet,<ref>M. P. de Villiers and J. van Heerden. [http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=73339 Clear air turbulence over South Africa.] {{Webarchive|url=https://web.archive.org/web/20131115004322/http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=73339 |date=15 November 2013 }} Retrieved on 8 May 2008.</ref> next to and just under the axis of the jet.<ref>Clark T. L., Hall W. D., Kerr R. M., Middleton D., Radke L., Ralph F. M., Neiman P. J., Levinson D. [http://cat.inist.fr/?aModele=afficheN&cpsidt=1345004 Origins of aircraft-damaging clear-air turbulence during the 9 December 1992 Colorado downslope windstorm : Numerical simulations and comparison with observations.] {{Webarchive|url=https://web.archive.org/web/20120127002040/http://cat.inist.fr/?aModele=afficheN&cpsidt=1345004 |date=27 January 2012 }} Retrieved on 8 May 2008.</ref> Clear-air turbulence can cause aircraft to plunge and so present a passenger safety hazard that has caused fatal accidents, such as the death of one passenger on [[United Airlines Flight 826]] in 1997.<ref>[[National Transportation Safety Board]]. [https://www.ntsb.gov/Pressrel/1997/971230.htm Aircraft Accident Investigation United Airlines flight 826, Pacific Ocean 28 December 1997.] {{Webarchive|url=https://web.archive.org/web/20090902231609/http://ntsb.gov/Pressrel/1997/971230.htm |date=2 September 2009 }} Retrieved on 13 May 2008.</ref><ref name="CNN UAF826">{{Cite news| url = http://www.cnn.com/US/9712/29/united.turbulence/ | title = NTSB investigates United Airlines plunge | author = Staff writer | publisher = [[CNN]] | date = 29 December 1997 | access-date =13 May 2008 |archive-url = https://web.archive.org/web/20080412021327/http://www.cnn.com/US/9712/29/united.turbulence/ |archive-date = 12 April 2008}}</ref> Unusual wind speed in the jet stream in late February 2024 pushed commercial jets to excess of {{cvt|800|mph|km/h kn}} relative to the ground.<ref>{{Cite news |last= Cerullo |first=Megan |date=23 February 2024 |editor-last= Picchi  |editor-first=Aimee |title=Some international flights are exceeding 800 mph due to high winds. One flight arrived almost an hour early |url=https://www.cbsnews.com/news/flights-over-800-mph-high-winds-early-arrival/ |url-status=live |archive-url=https://web.archive.org/web/20240301225339/https://www.cbsnews.com/news/flights-over-800-mph-high-winds-early-arrival/ |archive-date=1 March 2024 |access-date=14 June 2024 |work=CBS News}}</ref><ref>{{Cite news |last= Longo |first=Adam |date=20 February 2024 |title=Flight from Dulles to London hits 800 mph due to near-record winds |url=https://www.wusa9.com/article/weather/flight-dulles-london-800-mph-due-near-record-winds/65-d249e946-4e66-4abb-9de5-4df9bfaa8cb4 |url-status=live |archive-url=https://web.archive.org/web/20240221004928/https://www.wusa9.com/article/weather/flight-dulles-london-800-mph-due-near-record-winds/65-d249e946-4e66-4abb-9de5-4df9bfaa8cb4 |archive-date=21 February 2024 |access-date=14 June 2024 |work=WUSA9}}</ref>

===Possible future power generation===

{{See also|High-altitude wind power}}
Scientists are investigating ways to harness the wind energy within the jet stream. According to one estimate of the potential wind energy in the jet stream, only one percent would be needed to meet the world's current energy needs. In the late 2000s it was estimated that the required technology would reportedly take 10–20 years to develop.<ref>Keay Davidson. [http://www.sfgate.com/cgi-bin/article.cgi?file=/c/a/2007/05/07/MNGNEPMD801.DTL Scientists look high in the sky for power.] {{Webarchive|url=https://web.archive.org/web/20080607212714/http://www.sfgate.com/cgi-bin/article.cgi?file=%2Fc%2Fa%2F2007%2F05%2F07%2FMNGNEPMD801.DTL |date=7 June 2008 }} Retrieved on 8 May 2008.</ref>
There are two major but divergent scientific articles about jet stream power. Archer & Caldeira<ref>Archer, C. L. and Caldeira, K. {{usurped|1=[https://web.archive.org/web/20110915075738/http://www.awec2010.com/public/img/media/archer_caldeira.pdf Global assessment of high-altitude wind power, IEEE T. Energy Conver., 2, 307–319, 2009.]}} Retrieved on 24 October 2012.</ref> claim that the Earth's jet streams could generate a total power of 1700 [[Watt#Terawatt|terawatts (TW)]] and that the climatic impact of harnessing this amount would be negligible. However, Miller, Gans, & Kleidon<ref name="MGK">L.M. Miller, F. Gans, & A. Kleidon [http://www.earth-syst-dynam.net/2/201/2011/esd-2-201-2011.pdf Jet stream wind power as a renewable energy resource: little power, big impacts. Earth Syst. Dynam. Discuss. 2. 201–212. 2011.] {{Webarchive|url=https://web.archive.org/web/20120118233208/http://www.earth-syst-dynam.net/2/201/2011/esd-2-201-2011.pdf |date=18 January 2012 }} Retrieved on 16 January 201208.</ref> claim that the jet streams could generate a total power of only 7.5 TW and lacks the potential to make a significant contribution to renewable energy.<ref name="MGK" />

===Unpowered aerial attack===
Near the end of [[World War II]], from late 1944 until early 1945, the Japanese [[Fu-Go balloon bomb]], a type of [[fire balloon]], was designed as a cheap weapon intended to make use of the jet stream over the [[Pacific Ocean]] to reach the west coast of [[Canada]] and the [[United States]]. Relatively ineffective as weapons, they were used in one of the few [[American Theater (1939–1945)#Fire balloon attacks|attacks on North America during World War II]], causing six deaths and a small amount of damage.<ref>{{Cite web |url=http://www.faqs.org/docs/air/avfusen.html |title=The Fire Balloons |access-date=3 October 2009 |archive-date=3 March 2016 |archive-url=https://web.archive.org/web/20160303175214/http://www.faqs.org/docs/air/avfusen.html |url-status=live }}</ref> American scientists studying the balloons thought the Japanese might be preparing a biological attack.<ref>{{cite magazine |last=McPhee |first=John |date=29 January 1996|title=Balloons of War |magazine=The New Yorker|url=https://archives.newyorker.com/newyorker/1996-01-29|access-date=27 January 2024}}</ref>