View source for Talk:Jet stream

{{ArticleHistory
| action1       = GAN
| action1date   = 13 May 2008
| action1link   = Talk:Jet stream#GA nomination on hold
| action1result = listed
| action1oldid  = 212206845
| currentstatus = GA
| topic = Natsci
}}
{{meteorology|class=GA|importance=High}}
{{Weather-selected|month=06|year=2008}}

==Discovered by Thaddeus Lowe?==
The article about [[Thaddeus Lowe]] says:
: ''Thaddeus Sobieski Constantine (alt. Coulincourt) Lowe (1832–1913) was an American engineer. He was exactly 29 when he proposed the idea of observation balloons during the American Civil War. During the Civil War, he became the commander of the United States' First Balloon Corps division. He flew the Intrepid, one of six hot air balloons used during the Civil War in addition to the Enterprise. While doing so, he was captured as a spy in North Carolina. He later used his knowledge of balloons to discover the jet stream.''
Actually I doubt that... - [[User:Alureiter|Alureiter]] 18:14, 11 November 2005 (UTC)

===Child, you cut me to the Quick!===
''A quote from the Wizard of Oz just before he took off in a balloon.

I never realized this question about Lowe and the Jet stream existed. In the biographies of Lowe, he is spoken of as having recognized a high wind above winds that always blew to the East. In his Cincinnati to Unionville South Carolina balloon flight, he flew a high wind, in excess of 18,000 feet, to that spot. If that's not the Jet Stream, then I'll redact. Maybe somebody named it "Jet Stream" later on. The best of aviators of the day, 1857-1859, realized that a transatlantic flight could be made by this wind, even though it was never accomplished. Lowe's subsequent period of Civil War ballooning had nothing to do with Jet Stream flight. Add to that, the best scientists from the Smithsonian, including Lowe's mentor Prof. Joseph Henry, were sold on Lowe's meteorological calculations, some of the earliest ever documented. I remain yours truly, editor of the Thaddeus Lowe article--[[User:Magi Media|Magi Media]] ([[User talk:Magi Media|talk]]) 01:15, 25 May 2008 (UTC)

== Ooishi and Esperanto? ==

The article says that Ooishi's work on the Jet Stream "went largely unnoticed outside of Japan as he chose to write in the international language of Esperanto which was little read in scientific circles."

And Japanese *was* widely read in scientific circles in the 1920s??? The way the matter is phrased to me seems boardering on being non-neutral towards Esperanto...

:I don't think so - it would be true if he wrote it in any other language than those commonly used in international science circles (French and German for that era, I think, although I am very much uncertain of that).  It's not a comment on Esperanto, it's a comment on the language used not being a language commonly used in scientific papers of the era. [[User:69.162.59.13|69.162.59.13]] 14:31, 27 February 2006 (UTC)

::In my rewrite I've addressed this. Esperanto was preferred by scientists like Ooishi whose native languages were unlikely to be read by Europeans. Unfortunately, the Europeans didn't get the message. ;-) After WW2 English became the scientific language of choice. --[[User:Dhartung|Dhartung]] | [[User talk:Dhartung|Talk]] 22:24, 7 June 2006 (UTC)

== Fire balloons ==

The article says:

:"It was however utilised during World War II by the Japanese military in the fire balloon attacks on the American mainland (see below)."

But there is nothing below on the fire bombs :( [[User:129.241.11.199|129.241.11.199]] 14:26, 17 March 2006 (UTC)

::This is now hyperlinked to the article [[fire balloon]] [[User:Ma.rkus.nl|Ma.rkus.nl]] 16:01, 21 August 2006 (UTC)

== Factual error about Wiley Post ==

"During World War II the American aviator Wiley Post.."

Wiley Post died in 1935.  WWII started in 1939 and the U.S. entered the war in 1941.  Clearly either the timeframe is wrong or it was not done by Wiley Post.  [[User:MichaelSH|MichaelSH]] 04:27, 27 May 2006 (UTC)
:It's incorrect to write this as a competition between Ooishi and Post. Not even Ooishi fully understood what he had discovered, and the paper that was already linked to as the source did not overstate this, but its description here did. I've used that source to write a fuller history of the process of discovery that gives due credit to others including the German who first coined the term. --[[User:Dhartung|Dhartung]] | [[User talk:Dhartung|Talk]] 22:22, 7 June 2006 (UTC)
::Thanks for clearing this up.  The article now makes sense.  [[User:MichaelSH|MichaelSH]] 23:48, 10 June 2006 (UTC)

== Fastest speed ==

According to Guinness World Records 2006, a jet stream speed of 656 km/h (408 mph) was measured above [[South Uist]] December 13, 1967. More on the subject [http://www.univ-perp.fr/fuseurop/suist_e.htm here].

== Tailwind caused a stall ==
My comment refers to the Jet Stream article found at http://en.wikipedia.org/wiki/Jet_stream.  The text in question is quoted here:

“A 1943 Royal Air Force raid on Gironde, France, encountered tailwinds that sped them to their target, but returning the same headwinds, estimated at 380 km/h, caused their aircraft to stall, and the crews were forced to parachute into occupied Vichy France, where they were captured.”

I’m having trouble with the suggestion that the same headwinds, on the return trip, caused the aircraft to stall.  Airplanes fly within the air mass and as such have air speeds.  It really doesn’t matter which direction the air mass is moving, the aircraft is transiting that air mass at an airspeed that will allow it to continue flying.  If they somehow tried t slow the aircraft’s airspeed to provide a given ground speed, then it would be possible to slow the aircraft (airspeed) sufficiently to allow it to stall (a pretty dumb thing to do).  

There is a phenomenon encountered by airplanes approaching airports for landing (low altitude, slow airspeed, & perhaps hanging numerous lift/drag devices such as flaps and landing gear) in which a headwind quickly changes to a tailwind effectively causing the airspeed to drop to critical levels (and possible the aircraft to crash).  This “wind shear” effectively steals the lift from the wings and unless the pilot can return the airspeed to flying speed quickly, they will likely crash.

Even if the 1943 flight encountered such a wind shear at altitude, it should not have caused the aircraft to stall and the crew to abandon it.  Altitude is your friend in these situations and the 1943 flight should have been able to trade altitude for airspeed sufficient to maintain controlled flight.

If I missed the point of the article, I apologize in advance.  Please accept these thoughts in the spirit in which they were intended.

Thank you for an excellent article. {{unsignedIP|70.188.252.180}}

:Removed the text since no citation was added, and the statement does sound quite unlikely to me. [[User:Kumiankka|Kumiankka]] 22:12, 30 March 2007 (UTC)

::The statement comes from the article on Ooishi in the External links section: 
:::''Flohn (1992, p. 13) [Oral history memoir]''
:::''An English bomber squadron encountered NNE headwinds of 380 km h−1 (~106 m s−1) on return from a raid over Gironde (west coast of France) in 1943. Crews parachute from stalled aircraft and are captured by German Army.''
::The source cited is a German memoir ''Flohn, H., 1992: Meteorologie im Übergang Erfahrungen und Errinerungern (1931–1991). Ferd Dümmlers, 81 pp.'' It is only a report, but it was included in the overview used to rewrite this article, so I thought it significant. Flohn being a meteorologist and not an aerospace engineer I don't think we can determine whether it's realistic or not, but it is sourced. --[[User:Dhartung|Dhartung]] | [[User talk:Dhartung|Talk]] 01:42, 31 March 2007 (UTC)

:::: Wow. I'm surprised to see this aviation myth has even made it into print. The only logical explanation I can think of is them having run out of fuel if the headwind slowed their return enough, however it's not our place to speculate on that since that would be [[WP:OR|original research]]. However I suggest leaving the statement out as '''exceptional claims require exceptional sources''' ([[WP:CITE]]) Thanks for clarifying the matter :) [[User:Kumiankka|Kumiankka]] 22:16, 4 April 2007 (UTC)

::::: Keep in mind this may just be a mistranslation. I think "stalled" just as well implies the simpler case, that they ran out of fuel. The relevant point is that they encountered the extreme headwinds found only at those altitudes. Anyway, this has to have been documented elsewhere, so maybe we can find a better source. --[[User:Dhartung|Dhartung]] | [[User talk:Dhartung|Talk]] 05:29, 5 April 2007 (UTC)

:::::: I posted a question at the [[Wikipedia_talk:WikiProject_Military_history/Military_aviation_task_force#1943_bomber_bailout_over_Gironde|military aviation task force]]. Maybe somebody there has a suggestion. --[[User:Dhartung|Dhartung]] | [[User talk:Dhartung|Talk]] 05:40, 5 April 2007 (UTC)

: I remember a TV program that talked about B-29 crews discovering that they were flying in very strong winds.  The bomb sight calculated the wind from aircraft airspeed and an optical fix (a fixed point) on the ground.  The reported wind speed was off the scale and the crew abandoned the mission.  Fortunately they had an intelligence office on-board to vouch for the crew.  The result was that the B-20 couldn't use this bomb sight for accurate bombing and was obliged to 'carpet' bomb. More on the subject [http://www.weatheronline.co.uk/feature/bb270503.htm here]

----

The very first paragraph states, "Jet streams are fast flowing, relatively narrow air currents found in the atmosphere at around 11 kilometres (36,000 ft) above the surface of the Earth, '''just under the tropopause'''. They form at the boundaries of adjacent air masses with significant differences in temperature, such as of the polar region and the warmer air to the south. '''The jet stream is mainly found in the stratosphere.'''"

Since the stratosphere is found above the tropopause and not just under it, where exactly is the jet stream found?!

:This has been fixed.  [[User:Thegreatdr|Thegreatdr]] ([[User talk:Thegreatdr|talk]]) 20:02, 8 May 2008 (UTC)

== See also BOAC Flight 911 ==

*[[BOAC flight 911]] crashed after hitting severe [[Lee Wave]] [[Clear-air turbulence]] near Mt Fuji. This was a very sad accident. Clear-air turbulence is also encountered around jet streams, but this was not the case for Flight 911 (at just 4,900M) and so I have removed this link.--JollyTom 09:04, 24 August 2007 (UTC)

== Like Birds? ==

"In the Northern Hemisphere the streams are most commonly found between latitudes 30°N and 70°N for the polar jet stream (pilots remember that like birds they go north in the summer and south in the winter),"

What are we talking about here, do pilots go north in the summer and south in the winter, or does the jet stream. In my experiance the jetstream drops further to the south during the winter and gets pushed higher to the north during the summer. I could be... and probobly am... wrong though.
:I worded the passage more appropriately.  It was stated opposite to reality.  [[User:Thegreatdr|Thegreatdr]] ([[User talk:Thegreatdr|talk]]) 20:01, 8 May 2008 (UTC)

== Is there a way to harness energy from the Jet Stream to ease the strain? ==

Harnessing energy from the constant currents of Jet Streams may be a solution to some of Human energy concerns.  Perhaps there is a way to create nanotech instruments that can capture the currents power in the Tropopause. Sort of like Dams.  <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[User:Mahovictor|Mahovictor]] ([[User talk:Mahovictor|talk]] • [[Special:Contributions/Mahovictor|contribs]]) 04:56, 3 December 2007 (UTC)</small><!-- Template:Unsigned --> <!--Autosigned by SineBot-->
:I have added a section concerning this possibility.  [[User:Thegreatdr|Thegreatdr]] ([[User talk:Thegreatdr|talk]]) 21:26, 8 May 2008 (UTC)

Do any birds/insects/creatures use the jet stream besides us?  <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/67.164.65.21|67.164.65.21]] ([[User talk:67.164.65.21|talk]]) 03:17, 12 February 2008 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

== Jetstream direction ==

This article says jet streams flow from east to west.  Other web pages
dealing with jet streams say the opposite, that the winds flow from
west to east.
:This should be fixed now.  [[User:Thegreatdr|Thegreatdr]] ([[User talk:Thegreatdr|talk]]) 21:40, 8 May 2008 (UTC)

==Tropical or subtropical==
The article says "Northern Hemisphere (stream is)  between latitude 20°N and 50°N for the sub[[tropical]] (sic)".  Should that last word be [[subtropical]] or [[tropical]] without the prefix "sub"? [[User:Moriori|Moriori]] 02:27, Apr 9, 2004 (UTC)
:Subtropical.  Sorry for the very long delay.  I'm surprised no one answered you sooner.  [[User:Thegreatdr|Thegreatdr]] ([[User talk:Thegreatdr|talk]]) 17:06, 8 May 2008 (UTC)

==Wiley Post==
article states that jet streams were discovered during WW II by Wiley Post.  He actually died in 1935, but did discover them.
:A user has corrected the discoverer.  It was not him.  [[User:Thegreatdr|Thegreatdr]] ([[User talk:Thegreatdr|talk]]) 17:10, 8 May 2008 (UTC)

== ECMWF data ==

I'm a bit puzzled as to how the page text and piccies fit in with pix like http://www.ecmwf.int/research/era/ERA-40_Atlas/images/full/D25_XS_DJF.gif. Obviously thats a long-term mean and doesn't take account of meandering, but... there is really only one jet per hemisphere... they are clearly far more than a few km wide... and so on [[User:William M. Connolley|William M. Connolley]] ([[User talk:William M. Connolley|talk]]) 20:11, 11 May 2008 (UTC)
:If you average it out like that over 3 months, yeah, only one wind maximum shows up, and it is broad.  That doesn't mean there's only one jet per hemisphere though and that it is a thousand or so km/miles wide.  Of the sources I looked through (let alone personal experience) there are at least 2 main jet streams much of the time...the polar and subtropical...and usually the subtropical is only present in a couple pieces.  The polar is prone to splitting into 2 or more pieces from time to time, in unphased flow.  That graphic might be useful for the climate article though, if it were in the public domain (which it likely is not, being that the ECMWF is the source).  [[User:Thegreatdr|Thegreatdr]] ([[User talk:Thegreatdr|talk]]) 21:10, 11 May 2008 (UTC)

== GA nomination on hold ==
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#:a ''(references)'': {{GAList/check|yes}} b ''(citations to [[WP:RS|reliable sources]])'': {{GAList/check|yes}} c ''([[Wikipedia:No original research|OR]])'': {{GAList/check|yes}}
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Overall, the article is almost there. Here's the things I saw:
* There is a mention of the [[tropopause]] twice in the first paragraph of the lede. It is a little bit redundant to say the same thing twice—can it be condensed somehow? {{done}} [[User:Thegreatdr|Thegreatdr]] ([[User talk:Thegreatdr|talk]]) 12:46, 13 May 2008 (UTC)
* In the Discovery section: what is a pilot balloon? A dirigible, or just a hot-air balloon? {{done}} [[User:Thegreatdr|Thegreatdr]] ([[User talk:Thegreatdr|talk]]) 12:54, 13 May 2008 (UTC)
* A bit more detail about Rossby waves (e.g. that they're created by the Coriolis effect) would be helpful in the Description section. An extra short sentence or two would suffice. {{done}} [[User:Thegreatdr|Thegreatdr]] ([[User talk:Thegreatdr|talk]]) 13:08, 13 May 2008 (UTC)
*''"The CAT is strongest on the cold air side of the jet,[7] usually next to or just below the axis of the jet."'' - I'm confused by "below" here. Does that mean towards the equator? (I guess it makes sense for the Northern Hemisphere, but the directional analogy breaks down for the Southern Hemisphere.) 
**{{done}}  It was simpler than you thought.  The article merely meant underneath (vertically below), not a cardinal direction in the horizontal.  [[User:Thegreatdr|Thegreatdr]] ([[User talk:Thegreatdr|talk]]) 13:12, 13 May 2008 (UTC)
* In the Cause section, the relationship between temperature and pressure is a bit diffuse for non-technical readers. However, I'm not sure whether that should be explained in depth in this article, or if that explanation belongs in another article. Maybe saying "If two air masses of different temperatures and densities meet, the resulting pressure difference (which causes wind) is highest within the transition zone." would be sufficient.
**I made a couple changes to the wording, which should make the description clearer in that first paragraph.  See if that works for you.  [[User:Thegreatdr|Thegreatdr]] ([[User talk:Thegreatdr|talk]]) 13:15, 13 May 2008 (UTC)
* (Not for GA) - the atmospheric parcel description could be made more engaging by adding a picture of a control volume surrounding the atmospheric parcel.
* What are the effects of El Niño / La Niña associated with the jet stream outside North America? (This is the primary reason I put the article on hold)
**I found a reference mentioning that ENSO combined with PDO phase affects the jet stream over Europe.  I also found a reference regarding El Nino and South America.  North America definitely seems to be influenced most from ENSO, since it lies immediately downstream of the warming/cooling signals seen in the tropical Pacific and since it impacts during the Northern Hemisphere cold season.  In searches for Australia, ENSO influences to not extend to the jet stream.  [[User:Thegreatdr|Thegreatdr]] ([[User talk:Thegreatdr|talk]]) 14:42, 13 May 2008 (UTC)
* A few more links in the ENSO section would work (e.g. Gulf coast, Southeast, Rockies, Sierra Nevada, etc.) I didn't do these because I'm running a bit out of time to review the article.{{done}} [[User:Thegreatdr|Thegreatdr]] ([[User talk:Thegreatdr|talk]]) 13:20, 13 May 2008 (UTC)
* Ref #2 needs to be formatted similar to the rest of them (and needs an accessdate too).
**Did you mean ref #1?  Ref #2 looked ok.  {{done}} [[User:Thegreatdr|Thegreatdr]] ([[User talk:Thegreatdr|talk]]) 13:23, 13 May 2008 (UTC)
* Fill out the work parameter for Ref #19, so people can know it comes from the AOML FAQ. {{done}} [[User:Thegreatdr|Thegreatdr]] ([[User talk:Thegreatdr|talk]]) 13:24, 13 May 2008 (UTC)

Again, it shouldn't require that much work to get the article to GA status. [[User:Titoxd|Tito<span style="color:#008000;">xd</span>]]<sup>([[User talk:Titoxd|?!?]] - [[WP:FAC|cool stuff]])</sup> 23:51, 12 May 2008 (UTC)
: Looks good. The only thing that I see now is that since the Forecasting section was split off, it is now a little bit short. Would it be appropriate to mention [[trough (meteorology)|troughs]] and [[Ridge (meteorology)|ridges]] in this section, or not? [[User:Titoxd|Tito<span style="color:#008000;">xd</span>]]<sup>([[User talk:Titoxd|?!?]] - [[WP:FAC|cool stuff]])</sup> 20:56, 13 May 2008 (UTC)
::I moved the short section to description.  It looked out of place where it was initially anyhow.  See if that looks better.  [[User:Thegreatdr|Thegreatdr]] ([[User talk:Thegreatdr|talk]]) 21:03, 13 May 2008 (UTC)
:::Added refs for CAT mishaps.  [[User:Thegreatdr|Thegreatdr]] ([[User talk:Thegreatdr|talk]]) 21:31, 13 May 2008 (UTC)
:::: You edit-conflicted me when I was doing that, heh. It looks really good now, so I'll promote it. [[User:Titoxd|Tito<span style="color:#008000;">xd</span>]]<sup>([[User talk:Titoxd|?!?]] - [[WP:FAC|cool stuff]])</sup> 21:33, 13 May 2008 (UTC)


==Alternative JET STREAM theory==

The jet stream is caused by the rotation of the earth moving faster then the static air above the lower atmosphere]

There is a intermediate layer of stationary  air [fisenne zone?] with sufficient viscosity to interact with the lower atmosphere.  Simple inertia  of this layer  translates to an apparent high speed wind from the ground viewpoint.  Theoretically,  wind speed ranges from zero at the north and south poles to a thousand  miles/hr at the equator.  In fact, the strong heat thermals at the lower latitudes eliminate the static air. It is at the higher latitudes  that the constant dynamic interaction of the  lower atmosphere and the  static air. creates the configuration called the jet stream.


Note:The tremendous power of the jet stream in an easterly direction cannot be fully explained in any other way: yet the powerless static air relies upon the earth's lower atmosphere to provide the apparent  power.



My belief differs from conventional meteorology: but I am willing to bet a buck or two  that I am correct.
Submitted by Charles Fisenne 516-223-8899       2732  Park Ave. Baldwin N.Y.  11510
Replies welcome  cfisenne@verizon.net  <span style="font-size: smaller;" class="autosigned">—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/72.89.100.3|72.89.100.3]] ([[User talk:72.89.100.3|talk]]) 21:01, 6 January 2009 (UTC)</span><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->
:There are locations in the tropics that launch upper air balloons...which typically burst towards the 10 hPa level...or 100000 feet.  Measured winds rarely reach {{convert|200|kn}}, let alone higher, and close to 40000 feet up that occurs offshore Japan and the eastern portion of North America (higher than jet level winds trail off.)  I think the measured wind record aloft is on the order of {{convert|250|kn|mph}}.  If what you are saying were true, those kinds of winds would have been measured as long as 60 years ago (if below 100k feet) or been detected in the drift of rockets/shuttles that have been launched since the 1930s.  It's not a good idea to throw addresses or phone numbers on any of these pages, since there are copies of these pages kept (theoretically) forever.  [[User:Thegreatdr|Thegreatdr]] ([[User talk:Thegreatdr|talk]]) 22:00, 6 January 2009 (UTC)

== Left me scratching my head ==

The article states:

:"They are thought to be caused by a combination of atmospheric heating (by solar radiation and/or internal heat) and a planet's rotation on its own axis."

But if the jet stream moves in this direction, it would be moving faster than the earth is rotating.  The article could use more depth on the jet stream cause?  [[User:Ann arbor street|Ann arbor street]] ([[User talk:Ann arbor street|talk]]) 15:09, 8 June 2009 (UTC)

: It is a combination of overturning (caused by heating) leading to polewards motion in the upper levels which then accelerates the air (by coriolis forces). The jet streams are the fastest bit of this; past that, it breaks up into instability [[User:William M. Connolley|William M. Connolley]] ([[User talk:William M. Connolley|talk]]) 20:03, 26 September 2009 (UTC)

:: I've just re-written the important bit, though I left a lot of (probably rather dubious) stuff behind [[User:William M. Connolley|William M. Connolley]] ([[User talk:William M. Connolley|talk]]) 20:46, 26 September 2009 (UTC)

I disagree with Boris over this [http://en.wikipedia.org/enwiki/w/index.php?title=Jet_stream&curid=16472&diff=316402030&oldid=316387380] (we can leave the Coriolis aside for the moment). The fundamental *cause* is solar heating. Thunderstorms are just one mechanism - they might even be the most important, I don't know - but they aren't the cause [[User:William M. Connolley|William M. Connolley]] ([[User talk:William M. Connolley|talk]]) 08:16, 27 September 2009 (UTC)

:The original wording was "Tropical air heated by solar radiation..." which is wrong; heating of the air by absorption of solar radiation is small, and tropical air is heated mainly by sensible and latent heat fluxes. Introducing the idea that the ultimate heat source is the sun would be fine. [[User:Short Brigade Harvester Boris|Short Brigade Harvester Boris]] ([[User talk:Short Brigade Harvester Boris|talk]]) 14:24, 27 September 2009 (UTC)
:: OK, I left out some of the connecting words of course... it is heated by solar radiation, but that radiation goes via the ground, mostly. Also, of course, there is the element of organisation: a lot of the ground is heated, but ascent only occurs in a limited zone [[User:William M. Connolley|William M. Connolley]] ([[User talk:William M. Connolley|talk]]) 18:19, 27 September 2009 (UTC)

== polar night jet ==

A small number of articles talk about a "polar night jet". This seems to be an additional type of jet which seems to be higher (stratosphere?) than the normal jet stream and to occur only in winter months in the relevant hemisphere (hence "polar night"). Should information on this topic be a different article or in a subsection of this article? [[User:Feline Hymnic|Feline Hymnic]] ([[User talk:Feline Hymnic|talk]]) 23:24, 25 September 2009 (UTC)
:I've begun a section within this article. But I noticed that two sources, both cited in my new text, give very different values for the height: "80,000 feet" (BBC source) and "30 miles" (Alaska source). That seems to be a factor of two difference and clearly incompatible. Any experts out there able to resolve this? [[User:Feline Hymnic|Feline Hymnic]] ([[User talk:Feline Hymnic|talk]]) 17:52, 26 September 2009 (UTC)
:: You might find the pix at http://www.ecmwf.int/research/era/ERA-40/ERA-40_Atlas/docs/section_D25/parameter_zmzwsp.html help (in particular [http://www.ecmwf.int/research/era/ERA-40/ERA-40_Atlas/images/full/D29_XS_DJF.gif] for NH winter and [http://www.ecmwf.int/research/era/ERA-40/ERA-40_Atlas/images/full/D29_XS_JJA.gif] for SH winter). Mind you, those are zonally averaged. The SH winter max appears to be at about 2 hPa, and the NH above 1 hPa. 80,000 feet ~ 30km ~ 10 hPa, and 30 miles ~ 50 km ~ 1 hPa. So thats one down to the beeb. But Ian James's "Introduction to circulating atmospheres" (conveniently available from google books [http://books.google.co.uk/books?id=bZ2ARhIg--MC&pg=PA306&lpg=PA306&dq=polar+night+jet+height&source=bl&ots=3_YTFJP1-D&sig=rOpfSTfdGG_YOdcgH5utWo_oQcs&hl=en&ei=n3G-SvzzN8najQfTneAh&sa=X&oi=book_result&ct=result&resnum=4#v=onepage&q=polar%20night%20jet%20height&f=false] (fig 9.5) would put the core at 0.1 hPa it looks to me, ~60 km [[User:William M. Connolley|William M. Connolley]] ([[User talk:William M. Connolley|talk]]) 19:59, 26 September 2009 (UTC)

Incidentally, I'm not really sure about the "polar jet" stuff in the article. Can you see the polar jet in, e.g., this [http://www.ecmwf.int/research/era/ERA-40/ERA-40_Atlas/images/full/D01_LL_DJF.gif]? [[User:William M. Connolley|William M. Connolley]] ([[User talk:William M. Connolley|talk]]) 20:23, 26 September 2009 (UTC)

::Thanks. The ECMWF pictures are certainly colourful. But taking the perspective of a lay, non-meteorological, reader, what do they mean? I've tried to assemble the text from cited sources in a way that I (a non-met. person) could follow. But it could certainly do with revision, not least the apparent contradiction in altitudes. I get the feeling that the ordinary "polar jet" is reasonably tightly constrained in altitude to the tropopause (I think I now know roughly what that might be) which is itself reasonably tightly constrained in altitude (albeit varying with latitiude as per the picture in this article.) By contrast might the "polar night jet" appear at more or less any altitude (more or less unconstrained) in the stratosphere? Help, I'm struggling! [[User:Feline Hymnic|Feline Hymnic]] ([[User talk:Feline Hymnic|talk]]) 20:33, 26 September 2009 (UTC)

::: I don't think this is easy. The article sez ''Polar jet streams are typically located near the 250 hPa (7.38 inHg) pressure level, or 7 kilometres (4.3 mi) to 12 kilometres (7.5 mi) above sea level, while the weaker subtropical jet streams are much higher, between 10 kilometres (6.2 mi) and 16 kilometres (9.9 mi) above sea level.'' but the "much stronger" polar jets are very hard to reconcile with, e.g. [http://www.ecmwf.int/research/era/ERA-40/ERA-40_Atlas/images/full/D17_PS_DJF.gif] which is at their supposed strongest height of 250 hPa. But since the article links the PJ to the mostly-mythical [[Ferrel cell]] this isn't too surprising. This [http://www.ecmwf.int/research/era/ERA-40_Atlas/images/full/D29_XS_JJA.gif] makes it clear that the polar night jet is quite deep and doesn't have an easily-identifiable single altitude. Though those are both 40-year averages; a single year or day might well look different [[User:William M. Connolley|William M. Connolley]] ([[User talk:William M. Connolley|talk]]) 21:06, 26 September 2009 (UTC)

==Planets==
Lede sez "Jet streams, or just jets in context, are fast flowing, narrow air currents found in the atmosphere of '''planets''' at the tropopause, the transition between the troposphere (where temperature decreases with height) and the stratosphere (where temperature increases with height)." (emphasis added) Which planets other than Earth have a troposphere with a stratosphere above?  Since the lapse rate reversal in the stratosphere is mainly caused by ozone absorption of UV, I'm curious as to whether this generalizes to other planets. [[User:Short Brigade Harvester Boris|Short Brigade Harvester Boris]] ([[User talk:Short Brigade Harvester Boris|talk]]) 21:05, 26 September 2009 (UTC)

== upper-level and lower-level ==

Having done a little recent editing in an attempt to improve the article, it still doesn't seem right to me (a non-met. person who is trying to gain an understanding of the topic).  I think that one of the problems is that it still lacks some structure and, indeed, focus; and that one of the reasons for this is that it has (I think) ended up covering two different topics without realising it.  The major topic seems to be "jet streams" (global weather systems? polar and subtropical? Ooishi (1920s)? WW2? commercial aircraft? etc.)  The other seems to be more localised phenomena (barrier jet? African, Australian winds? etc.)  My guess is that these two topics are really largely different (perhaps a little overlap) but that happen to share a common name "jet".

Might it help it if we consider splitting this article into two separate ones?  Presumably the global weather article (polar, subtropical etc.) would retain the title "jet stream".  What might the other be called?

Just a thought. [[User:Feline Hymnic|Feline Hymnic]] ([[User talk:Feline Hymnic|talk]]) 20:22, 27 September 2009 (UTC)
:A jet is just a maximum of wind.  It could be low level or upper level.  Since both are considered jets, they both belong in the article, even if they're caused by different processes.  [[User:Thegreatdr|Thegreatdr]] ([[User talk:Thegreatdr|talk]]) 13:45, 24 October 2009 (UTC)

::Indeed. And thanks for your reply. I think the distinction, now becoming clearer (to me as a non-met. lay-reader), is a terminological one, between 'jet stream' and 'jet'. It seems that the term 'jet stream' specifically refers to the polar and sub-tropical jets (maybe also other upper-level jets, perhaps?) whereas 'jet' is a more general term describing both the principle of all jets and as a over-arching term to accommodate the known instances (both upper-level 'jet streams' and the various lower-level phenomena).
::Try skim-reading the article, without getting too immersed in detail, and at each paragraph ask the question: ''Is what is being described in this paragraph a 'jet-stream' (global polar/sub-tropical etc.) or one of the other 'jets'?''. This distinction isn't always clear; it is for that reason I'm proposing a split of the article.  (Of course, if we can make this single article clearer to the lay-reader, that would be fine.) [[User:Feline Hymnic|Feline Hymnic]] ([[User talk:Feline Hymnic|talk]]) 16:09, 24 October 2009 (UTC)

== Origin of the name "jet stream" ==

Jet streams may have been known for a long time, but I'd always understood that the term "jet stream" was only coined in the 1950s when jet passenger aircraft flying at altitudes of 30,000ft and higher started to encounter them regularly on the trans-Atlantic crossing.  Can anyone shed some light on this?
--[[User:Recoloniser|Recoloniser]] ([[User talk:Recoloniser|talk]]) 11:52, 3 January 2010 (UTC)

: The answer is in the first numbered subsection "Discovery". (Jetstram translates litarally from "Strahlströmung"). Interestingly, German Wikipedia says the term Jetstream dates from 1944. [[User:Marc1966|Marc1966]] ([[User talk:Marc1966|talk]]) 09:47, 22 February 2010 (UTC)

== What is the 2nd reason for narrow jets ==

[[Jet stream#Cause]] says "There are two factors that contribute to this sharpness of the jets. One is the tendency for developing cyclonic disturbances in midlatitudes to form fronts — sharp localized gradients in temperature."    but doesn't say what the 2nd factor is (or provide a source). [[User:Rod57|Rod57]] ([[User talk:Rod57|talk]]) 18:58, 10 January 2010 (UTC)
:The article was rearranged 2 years ago after GA passage.  The second factor is still there, it was just not labeled as such.  I added in the wording to clarify the situation.  [[User:Thegreatdr|Thegreatdr]] ([[User talk:Thegreatdr|talk]]) 04:27, 17 April 2010 (UTC)

== First discovery? ==

The article credits a Japanese scientist for first noticing the phenomenon, but this evening's [[PBS NewsHour]] has a piece that makes it earlier and links it to following the spectacular sunsets that followed the [[Krakatoa]] explosion in 1883. They interviewed a person who had written a book about this. 

It is probably worthwhile looking into this. [[User:Billjefferys|Bill Jefferys]] ([[User talk:Billjefferys|talk]]) 22:57, 16 April 2010 (UTC)
:Looks like someone just added it.  [[User:Thegreatdr|Thegreatdr]] ([[User talk:Thegreatdr|talk]]) 04:28, 17 April 2010 (UTC)

== Origin of the term ==

A number of pop and news articles say something to the effect that Seilkopf inventer the term "jet stream", and this claim found its way into wikipedia. Notice that [http://en.wikipedia.org/enwiki/w/index.php?title=Jet_stream&action=historysubmit&diff=358693986&oldid=358690040 the cite given (on the left pane)] says nothing like this. Early German books typically write about Seilkopf's term, like, " 'Strahlströmung', English term 'jet stream'". The modern German synonym is "Starhlstrom".

By the way, please do not remove red linking from articles: a red link is useful: it brings an attention to the fact that an article is missing.