Talk:Jet stream

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Contents

[edit] 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... - Alureiter 18:14, 11 November 2005 (UTC)

[edit] 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--Magi Media (talk) 01:15, 25 May 2008 (UTC)

[edit] 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. 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. --Dhartung | Talk 22:24, 7 June 2006 (UTC)

[edit] 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 :( 129.241.11.199 14:26, 17 March 2006 (UTC)

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

[edit] 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. 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. --Dhartung | Talk 22:22, 7 June 2006 (UTC)
Thanks for clearing this up. The article now makes sense. MichaelSH 23:48, 10 June 2006 (UTC)

[edit] 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 here.

[edit] 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. —Preceding unsigned comment added by 70.188.252.180 (talk)

Removed the text since no citation was added, and the statement does sound quite unlikely to me. 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. --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 original research. However I suggest leaving the statement out as exceptional claims require exceptional sources (WP:CITE) Thanks for clarifying the matter :) 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. --Dhartung | Talk 05:29, 5 April 2007 (UTC)
I posted a question at the military aviation task force. Maybe somebody there has a suggestion. --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 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. Thegreatdr (talk) 20:02, 8 May 2008 (UTC)

[edit] 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)

[edit] 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. Thegreatdr (talk) 20:01, 8 May 2008 (UTC)

[edit] 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. —Preceding unsigned comment added by Mahovictor (talk • contribs) 04:56, 3 December 2007 (UTC)

I have added a section concerning this possibility. Thegreatdr (talk) 21:26, 8 May 2008 (UTC)

Do any birds/insects/creatures use the jet stream besides us? —Preceding unsigned comment added by 67.164.65.21 (talk) 03:17, 12 February 2008 (UTC)

[edit] 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. Thegreatdr (talk) 21:40, 8 May 2008 (UTC)

[edit] Tropical or subtropical

The article says "Northern Hemisphere (stream is) between latitude 20°N and 50°N for the subtropical (sic)". Should that last word be subtropical or tropical without the prefix "sub"? Moriori 02:27, Apr 9, 2004 (UTC)

Subtropical. Sorry for the very long delay. I'm surprised no one answered you sooner. Thegreatdr (talk) 17:06, 8 May 2008 (UTC)

[edit] 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. Thegreatdr (talk) 17:10, 8 May 2008 (UTC)

[edit] 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 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). Thegreatdr (talk) 21:10, 11 May 2008 (UTC)

[edit] GA nomination on hold

GA review (see here for criteria)
  1. It is reasonably well written.
    a (prose): b (MoS):
  2. It is factually accurate and verifiable.
    a (references): b (citations to reliable sources): c (OR):
  3. It is broad in its coverage.
    a (major aspects): b (focused):
  4. It follows the neutral point of view policy.
    Fair representation without bias:
  5. It is stable.
    No edit wars etc.:
  6. It is illustrated by images, where possible and appropriate.
    a (images are tagged and non-free images have fair use rationales): b (appropriate use with suitable captions):
  7. Overall:
    Pass/Fail:

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? Y Done 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? Y Done 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. Y Done 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.)
    • Y Done It was simpler than you thought. The article merely meant underneath (vertically below), not a cardinal direction in the horizontal. 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. 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. 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.Y Done 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. Y Done 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. Y Done Thegreatdr (talk) 13:24, 13 May 2008 (UTC)

Again, it shouldn't require that much work to get the article to GA status. Titoxd(?!? - cool stuff) 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 troughs and ridges in this section, or not? Titoxd(?!? - cool stuff) 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. Thegreatdr (talk) 21:03, 13 May 2008 (UTC)
Added refs for CAT mishaps. 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. Titoxd(?!? - cool stuff) 21:33, 13 May 2008 (UTC)