Talk:Atmospheric circulation

Conservation of energy
"The poleward movement of the air in the upper part of the troposphere deviates toward the east due to the coriolis acceleration (a manifestation of conservation of energy). "

The parenthesis makes little sense. The Coriolis effect has very little to do with conservation of energy. Conservation of momentum perhaps, but really that parenthesis should just be removed. — Preceding unsigned comment added by 85.129.91.130 (talk) 05:51, 9 December 2016 (UTC)

naive reader question
One feature of the evening weather reports in the U.S. that is obvious to the naive viewer (me) is that fronts move from west to east. On another discussion page I asked why and was answered "Coriolis effect". I did skim that article and the present one. In a vague way I guess I see why but I would like to see the question addressed directly in a separate early section. I suspect that I am not the only one who would appreciate a full treatment.

naive reader   —Preceding unsigned comment added by 128.241.111.27 (talk) 23:07, 15 April 2008 (UTC)

March 2004 changes
(William M. Connolley 20:54, 2004 Mar 10 (UTC)) I want to make some major-ish changes to this page and a set of linked atmos pages. Just for a novelty, I thought I'd discuss them first...

There are several pages (this one; Hadley cell, wind, perhaps others) all of which have partial descriptions of the atmospheric circulation on them. I think that they should be unified, probably here, and some text stripped from those pages (not all, of course).


 * I would prefer not to see these pages blended. The problem is not that there is anything intrinsically wrong with this, but rather that as it stands, Wikipedia will not do a partial title search and has no effective index. Until those issues are resolved, I believe individual topics should stand as such. Moreover, topics such as 'Wind' are only peripherally related to 'Atmospheric circulation', and in the same way that I would find separate articles for 'hydrological cycle' and 'rain', so too ought 'wind' exist so as to discuss the finer points of advection.


 * (William M. Connolley 19:27, 2004 Mar 12 (UTC)) I've had a bit of a rethink on this. What I shall (probably) do now is to write my own page with what I want on it and see where that fits.

But also: I think there are several problems with the existing text, which needs mods: in particular:


 * The ocean transports heat too
 * Indeed. And I agree mention ought be made of that. However, I have very little knowledge of the exact nature of the ocean/atmosphere interaction except for a few special cases such as Walker circulation/ENSO/etc which have captured my imagination, and rather than just add a sentence which says "And oh, by the way, the ocean is involved too" without explaining further, I felt more comfortable in saying nothing at all.
 * OK, I shall do something then.


 * There is a load of fractal stuff in the intro to atmos circ. Firstly, this stuff is of marginal relevance: on the large aggregated scale the atmos cicr *isn't* fractal. Secondly, it isn't even true on the micro/mesoscale. The exact location of an individual cloud is *random* but on the large scale the convection is organised into patterns - not random at all. See various satellite piccies (err, I'll find one if you doubt this). And soup is the same: you tend to get a pattern of hexagonal cells. *But* this is second-order stuff: not the large scale.
 * Agreed, and no reluctance to accept changes. The main point here was that even short-term meteorological change is not predictable, and it is within chaos theory that we find the reason why.
 * OK, I'll "refactor" (Ed Poors phrase) that bit a bit then.


 * "It is a closed circulation loop, which begins at the equator with warm, moist air lifted aloft as an equatorial low pressure areas" needs rephrasing: the ascent *causes* the low pressure.
 * Again, I agree. Ascent --> low is a fundamental assumption, and I guess the wording there needs to be looked at.


 * "Some of the descending air travels equatorially" is inconsistent with the description of it as a closed cell - it needs to be all, or its not closed...
 * I'm inclined to disagree here, in the sense that I don't agree that the Hadley cell is truly closed. First, there is mixing in the subsidence zones, and while I've not seen hard data to indicate the extent, I would assume it to be measurable. (I would also note that the Nuclear Winter models of several years back show ready hemispheric mixing, with the primary mixing barrier being the ITCZ. Moreover, I found a curious lack of consensus in which way upper airflow at the Rossby/Ferrel cells travelled. I must have looked at a dozen diagrams and summaries; there was an even split between those sources which showed the upper Ferrel flow as poleward (ie, the Hadley cell contributing), and those which showed the flow moving toward the equator. Since all sources are in agreement that the Ferrel cell is a secondary circulation feature, I prefer the more conservative perspective that airflow in this region is consistent with standard models, which would have air descending at the Horse Latitudes and ascending at the Polar front.
 * I think the Ferrel cell is actually quite hard to understand. I'm planning to research this a bit before writing about it :-)


 * Phrases such as "the rising air masses contact the tropopause at about 8 km and move along its underside toward the poles" are too simplistic: this implies air moving at the tropopause and along the surface but not in the mid-atmosphere, which is wrong.
 * I agree that the wording can lead to that conclusion. I encourage you to modify it to eliminate the sense of an inert mid-atmosphere.
 * OK


 * "It can be argued that the Polar cell is the primary weathermaker for regions above the middle northern latitudes" - hmm, sounds wrong. Not for midlatitudes, surely?
 * Surely! At least in North America. Considering 45°N as the center of the mid-latitude zone, we see that it takes in the northern tier, but no more, of the American states, and contains all of Canada. In summer, this zone's weather is almost entirely the result of activity along the polar front, and in winter, that zone drops even further south. There are times during our winter when the entire nation is north of the polar front, yet at roughly the same latitude as Glasgow, I hardly consider my town northerly.
 * Oh great, I missed "above" in the text I quoted. So you're right.

Thats enough nitpicking to be going on with...
 * I'm always willing to pick a nit or two.Denni

Fractal stuff
Took a look at the changes - the article continues to look good. I remember why I included the fractal stuff. I'm sure you appreciate that fractal &#8800; random. Quite the opposite, AAMOF. The point here was to help readers understand the large atmospheric movements by relating them to something human-sized. And, in fact, exactly the same rules of physics apply at the mesoscale as at the microscale. Denni 23:41, 2004 Mar 14 (UTC)

See Air mass
William, you might want to have a go at Air mass - now there's a sad little page that really needs a hand. I'll watch it for a while; if you decide not to tackle it, I'll give it a little help. Denni 05:11, 2004 Mar 15 (UTC)


 * (William M. Connolley 23:03, 2004 Mar 15 (UTC)) Tonight I seem to be busy uploading pics of Stephenson's rocket I took last weekend... so the science will have to wait a day or two.

Does the Ferrel cell exist?
A new page, Ferrel cell is currently up on VfD. It is by an anon who says Ferrel cells do not exist. I am copying the current contents of this page to Talk:Atmospheric circulation/Ferrel cell critique to preserve it for discussion here. [[User:Dpbsmith|Dpbsmith (talk)]] 15:58, 16 Sep 2004 (UTC)

Oh, and please, by all means, anyone knowledgeable in this area please join the VfD discussion at Votes_for_deletion/Ferrel_cell. [[User:Dpbsmith|Dpbsmith (talk)]] 16:01, 16 Sep 2004 (UTC)
 * I am the author of the original article on atmospheric circulation, and did considerable research in preparing this article. Either the vast majority of climatologists is wrong, or the Ferrel cell exists. It is not clearly defined, since it is a secondary circulation feature, but it unambiguously occupies the space between the Hadley cell and the Polar cell, both of which have clearly defined boundaries. The Ferrel cell acts as kind of an "idle gear" between them, and, given that the Earth's circulation pattern is a closed system, is required to exist to balance the forces at work. Denni &#9775; 00:51, 2004 Sep 17 (UTC)


 * Added some text on Ferrel cell, agree that it's a secondary feature, which at many times is cut by Siberian or North American Highs.

Polar cell?
I find myself dubious about the contents of the polar cell bit. Over Antarctica, at least, I think that the bulk of the circulation in this cell is katabatic driven... I might even find a pic to prove this. Not sure about the north William M. Connolley 20:45, 25 June 2006 (UTC)

Fallout hot air rises
How would the prevailing winds distribute nuclear fallout if Iran were attacked? Iran is situated in the area of the 30 parallel where air is generally sinking. However, nuclear fallout would be very hot and have a tendency to rise until it is cooled. —Preceding unsigned comment added by 74.139.33.158 (talk • contribs) 21:08, 7 January 2007


 * This is probably too difficult topic for you.

Coriolis strongest
Just a drive-by edit. I removed "In addition, the coriolis force is strongest in the region where the Ferrel cell is" since this is apropos of nothing and is incorrect as well.

Lkeiner 04:07, 20 March 2007 (UTC)

Orographic circulations?
Nice longitudinal and latitudinal, how about a section on orographic circulations? -- Anonymous 14:23, 10 April 2007 (UTC)

High pressure at Horse Latitudes
I read from several sources stating that there is a high pressure at Horse Latitudes. It stops the flow of aloft warm air of the Hadley cell. It also causes winds blow towards the poles at the surface, known as the Westerlies.

However, I cannot find why there is always a high pressure at Horse Latitudes. Normally locations nearer the equator would be warmer and thus there is a low pressure, just like Hadley cell and polar cell. Why is it different for Horse Latitudes? I think it is important and should be included in the article. Does anyone know the answer? Salt 10:04, 24 May 2007 (UTC)

Atmospheric circulation on other planets
I think there should be a section about this, but when I added some stuff, it got reverted. - J kasd  15:47, 9 April 2008 (UTC) Again, I think it would be useful to have more information about this here; the atmosphere page is about atmospheres in general, and the circulation section there that links to here mentions Jupiter. Any other opinions?  J kasd  00:34, 24 April 2008 (UTC)

AtmosphCirc2.png is blank
This image is black on my Windows XP Pro notebook computer. It shows no detail at all when clicked on, and probably needs to be replaced.

uriel8  (talk)  19:49, 17 January 2009 (UTC)

Number of Cells
Is there any explanation as to why there are three cells in each hemisphere? Why not four or five? Is there something special about +/- 30 and +/- 60 that leads to these divisions? 128.100.76.35 (talk) 21:25, 15 April 2009 (UTC)

Merge with Prevailing Winds
This article is talking essentially about the same phenomenon as Prevailing winds and therefore a merger of two articles should be considered.

abhishek singh (talk) 00:58, 7 March 2011 (UTC)
 * Not really. Atmospheric circulation is three dimensional, talking about vertical winds and winds aloft, while prevailing winds are only talking about surface winds which prevail at certain locations on the Earth's surface.  That means that the Prevailing winds article is a subarticle of this one.  If there was no difference or hierarchy involved, prevailing winds would win hands down since it is GA, and this one is Start class.  My vote for merger would be NO.  Thegreatdr (talk) 23:10, 16 July 2011 (UTC)

Hadley cell diagram needs work
In the Hadley cell diagram, the surface flows appear to be blue on the globe, but red in the cell diagram at the edge. That is extremely confusing. You may be trying to say something about heat transport, but it doesn't work. Burressd (talk) 20:48, 11 December 2011 (UTC)

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Polar Easterlies
There is a discussion that the polar easterlies should be included in the section for atmosperic circulation, my experience has been that this is an important part of our atmospheric circulation between the months of September and February when the atmospheric pressure drops in the United States I am still doing research on this any input would be helpful.

C. A. Levingston 19:36, 6 October 2016 (UTC) — Preceding unsigned comment added by Caleving (talk • contribs)

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Inconsistent colour coding on "An idealised view of three large circulation cells showing surface winds"
Hello: the colour coding on the illustration "An idealised view of three large circulation cells showing surface winds" is misleading. For example, while the easterly wind aloft in the Hadley cell is colour-coded light blue, the same colour is used for its surface "counterpart", the westerly wind on the map. This is confusing, somehow in contrast also with the accompanying text (though no color reference is given there). Moreover, the colours used are typically coding cold and warm temperature, which does not seem to be case here (or is it?). As a scientist with experience in presentation of scientific concepts (although not in meteorology), I would correct this.(Lot56 (talk) 11:31, 20 January 2019 (UTC))

Awful
I am sure a lot of work has gone into this awfully bad article. But a quick look shows some serious problems. First, the first image showing the 3 cells (6 for both N & S latitudes) is simply bad. The list of problems is long: What the heck are the red lines supposed to be indicating? Why is there a small red oval between the Hadley & Mid-lat cells? What does the little red arrow pointing from the Hadley to the ML cells mean? Why does the red line (at about 30 N) drop almost straight down towards ground then rise into a loop-de-loop (a loop on top of a loop, a figure 8) near the edge of the polar cell? Why does the line again drop nearly vertically and then slowly rise inside the polar cell? Why does it appear to collide with itself in the polar cell? I am not asking questions because I want to know the answers but rather to point out how confusing, unclear, and irrelevant these red lines are. Surely anyone with average vision can see that the cells in the eastern half are elevated above the Earth's surface (in the diagram) while in the west they're not. Is that meaningful? What is below them? Why does the entire Hadley cell appear to be at a higher altitude than the other two cells? The southern HC drops at 30 S and logically the diagram shows the ML cell rising there, but the red line in the north suggests that's not the case there. There are a series of light-yellow lines which *might* be taken to be either surface winds (what ever that means) or E-W wind atmospheric motion. Three of the lines which seem to be showing the Northeasterly Tradewinds seem generally consistent, but one line starts above 30N and initially points to the East before curving down and to the West. There is also a problem with the lines depicting (?) the Southeasterly Trades: three of them end at the Equator (rather than the Intertropical Conv. Zone) and one actually makes it to the ICZ. Then there's an extra line which moves south instead of north and while it starts easterly, it curves around till it is westerly (and crosses over 30S) to become a Westerly. In both ML-cells, there are two sets of lines; one set nearest to 30N & 30S is predominantly Westerly and pole-wards of those lines is another set which is predominantly poleward in direction (N above 30N and S below 30S). Then there's the fact that while in the article the term Ferell cell is used (exclusively as far as I can see), in the diagram, AS WELL AS IN THE MAIN ARTICLE ON HADLEY CELLs, the term Mid-latitude cell is used. And one minor quibble, the yellow line at 60N does not lie uniformly on the Earth at 60N, someone needs to improve his photoshopping. The Third Graphic shows the 3 cells (and names the Ferrel cell) but also shows that the Hadley cell is 2.5 to 3 times as high as the other two cells, making the Earth's atmosphere American Football shaped (in cross-section). No explanation is given for this implausible shape. (I doubt if Corriolis forces and/or hot air would cause such a distortion, but I may be wrong here...) Finally, the claim is made that the Hadley cell is a "closed loop". It is not. There is *some* mixing. It is an egregious (imho) blunder to make an absolute statement - unless in context it is absolutely true.40.142.185.108 (talk) 20:36, 18 June 2019 (UTC)
 * I have left a message with commons:User talk:Kaidor inviting the uploader of the image to discuss it, here. HopsonRoad (talk) 23:02, 18 June 2019 (UTC)
 * Hi! I am the one who drew the first picture and I have to apologize for such a long delay in answering. This drawing was made after I discovered its source in the diagram_images_that_should_use_vector_graphics. This source, in turn, was made on the basis of a picture from the NASA page (now deleted, but a copy was preserved in archive.org). I must also say that I have nothing to do with meteorology or climatology. I just decided to vectorize the drawing and transferred all its flaws to the vector. But I am undoubtedly ready to fix them if you tell me exactly what needs to be changed. PS: I speak English very poorly, so all my language errors are on the conscience of Google translator. Kaidor (talk) 13:21, 17 August 2019 (UTC)
 * Thank you for your work in creating this graphic and for responding here! The more you can do to make the graphic reflect the source, the better. Here are some things that you could do to address the above editor's remarks:
 * Remove the red lines in the upper left portion of the image.
 * Flip the 30°N and 60°N lines so that they curve up, rather than down.
 * Remove the two items of text that say "Tropopause in ... zone".
 * Bring the circulation cells in the upper left portion of the image to where they are the same distance away from the planetary surface, as the other cells.
 * Restore the blue oval lines of circulation at the ends of those same cells.
 * If you can do these things, it would be much appreciated! And BTW, Google Translate was very clear! Cheers, HopsonRoad (talk) 20:20, 17 August 2019 (UTC)
 * ✅ File:Earth Global Circulation - en.svg --Kaidor (talk) 16:08, 29 August 2019 (UTC)
 * Nice job! Thanks, Kaidor! Cheers, HopsonRoad (talk) 00:58, 30 August 2019 (UTC)

mistake in first picture
the first heading picture does not show polar east-wind. --Konfressor (talk) 14:58, 25 April 2021 (UTC)