Talk:Thermal wind

"The equation also makes obvious that the thermal wind does not apply close to the equator: f is close to zero there."

I am not sure if this is an accurate statement. In the equation used, which is simply the geostrophic wind modified to be used between two pressure levels in the atmosphere rather than the sfc and some final height, when f approaches 0 then the K component of the cross-product becomes infinitely large. Therefore under an equivalent average temperature gradient in the tropics compared to mid-latitudes the wind should actually be stronger in the tropics. The reason we do not see very fast wind shear with height in the tropics is due to the lack of any strong temperature gradients.

24.154.96.47 22:32, 22 November 2005 (UTC)


 * I rewrote it a bit (put the f on the other side). See what you think. James (intro to circ atmos) states that the TWE doesn't determine the wind in the tropics. William M. Connolley 23:09, 22 November 2005 (UTC).

Oy...three articles tackling the same topic!
Wind gradient, wind shear, and thermal wind completely overlap. I propose all three be merged together, with thermal wind being part of the wind shear article. Comments? Thegreatdr 23:15, 28 November 2006 (UTC)


 * Well spotted. Wind gradient barely exists and should be merged into wind shear. But TW shouldn't be merged, being a specific topic of its own not normally considered in the same breath as WS William M. Connolley 23:28, 28 November 2006 (UTC)


 * The merging of wind gradient and wind shear is reasonable, though gradient should go into shear. Thermal wind as well as geostrophic wind, gradient wind, and similar warrant their own articles being separate terms of distinct usages.  They should be expanded if size/content is the concern and you were thinking of consolidating under one umbrella article.  Evolauxia 23:46, 28 November 2006 (UTC)


 * Wind shear is definitely not identical to the thermal wind. Thermal wind is a special case of wind shear, that, on the synoptic scale, under the assumption of geostrophic balance, is due to horizontal temperature gradients, and is defined as the vertical shear of the *geostrophic* wind.  Vertical wind shear can occur on smaller scales that is not in thermal wind balance, if the flow is highly ageostrophic (such as near thunderstorms for example).  I made a minor edit to the article to clarify the definition.

I believe the points above are valid. I'm working on merging out thermal gradient currently... but even without the consideration that thermal wind is only valid for geostrophic wind (which is a very valid reason not to merge), I don't think they can be merged because both have enough material to warrant their own topic. Thermal wind is a mathematical proof of relationship between two things that from layman observation don't seem to be related, while wind shear is more an observational topic. I mean, I suppose I could see thermal wind being a subsection of wind shear, but I think the perspective of the articles are so different that you can't merge them. In reality, we'd have to merge thermal wind into both wind shear and temperature gradients. It'd be like merging out geostrophic wind into coriolis force and pressure gradient force. I'm going to remove the merge tags. JeopardyTempest 02:22, 11 January 2007 (UTC)

Expert tag
Article may benefit from some general cleanup. Also, please check this revision for accuracy. I know nothing about the subject, so I will be unable to assist. - Rjd0060 (talk) 21:40, 23 January 2008 (UTC)

Latest Rewrite
I wrote the last revision of the article. I'm a professor of atmospheric and understand thermal wind very well. It is factually accurate and has illustrations. I wasn't logged into wikipedia when I uploaded it because I'm using at computer in the hotel while at the American Meteorological Society annual meeting and forgot to sign in to wikipedia first. Nedtheprotist (talk) 21:45, 23 January 2008 (UTC)

I'll remove the expert tag and start citation when I return home. —Preceding unsigned comment added by Nedtheprotist (talk • contribs) 21:46, 23 January 2008 (UTC)
 * Once there are enough inline references, it could be considered for GAC. It will be up to the reviewer/s as to whether or not the article is written simply enough for the lay person.  22:54, 23 January 2008 (UTC)

Well professor, you are wrong. The simple thermal wind relation has been history since 1985. It is still taught to undergraduates because it can be derived easily. Hank Stommel's Beta-spiral was the first attempt at removing the constant of integration, or estimating Vref. That is he believed the density field defines the total velocity field, away from boundaries. Some attempts were made at developing inverse methods for data analysis, but with mixed results. George Needler eventually proved Stommel's idea (Progr Oceanogr, 1985) by giving the total material velocity in closed form as a function of density. This discovery has not yet found its way into practical oceanography nor into data assimilation methods. What really interests me is the amount of time it takes for such forefront discoveries to trickle down to the average academic/researcher. When a leading physicist makes a major discovery, every physicist knows about it withing a week. When a climatologist proves some discovery, all the others learn about it 30yrs later.27.33.251.24 (talk) 06:02, 30 December 2015 (UTC)

Approximation
What if the cross product was removed? e.g.:

$$\begin{align} \frac{\partial u}{\partial z} &= -\frac{g}{\rho_\circ f} \frac{\partial \rho}{\partial y}\\ \frac{\partial v}{\partial z} &= \frac{g}{\rho_\circ f} \frac{\partial \rho}{\partial x} \end{align}$$

To me, these expressions are more clearly understood than the current ones. Whatever the case, the variables ($$\phi$$, $$v_T$$) in the equations need to be more clearly defined than they currently are. I also think pointing out that the gradient of $$\rho$$ (or $$\phi$$... is this just $$g\rho/\rho_\circ $$?) should be along constant pressure surfaces is important. —Preceding unsigned comment added by Levikilcher (talk • contribs) 21:04, 11 February 2009 (UTC)

Lead section
Thank you for improving the article. To my eyes, the lead section is still a bit inscrutable to a non-expert reader. I'm glad to know it's now more accurate (taking your word for that part). But is it possible to break down a bit of the jargon and explain it in simpler terms? It could certainly be longer -- a lead section is often several paragraphs. (See WP:LEAD for some general tips on what is desirable in a lead section.)

Also, I see you removed the claim that TW is a misnomer, and that its being a "wind shear" is at odds with the idea of it being a "wind." Was that an inaccurate claim? If it's accurate, I think it should be stated -- but if not, of course it's a good thing to remove it. In any case...thanks for working on this, great to have expert eyes on a significant article! -Pete (talk) 22:43, 6 July 2016 (UTC)


 * Also, do you happen to have access to the ISBN number for the Cushman-Roisin reference you added? That's a nice thing to include, as it will make it easier for readers to track the book down. -Pete (talk) 22:51, 6 July 2016 (UTC)

Pete, I expanded the lead and attempted to improve its accessibility. Also, I put the misnomer concept back in, since it is commonly mentioned by authors. I added the ISBN, too. I hadn't noticed the field in the visual editor, but will know it is there in the future. Thanks! --Mjh2016 (talk) 01:47, 7 July 2016 (UTC)