Talk:Potential temperature

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Untitled

I would say this is a basic concept/definition in climate science. Which is different from both meterology and physics.

WikiProject class rating

This article was automatically assessed because at least one WikiProject had rated the article as start, and the rating on other projects was brought up to start class. BetacommandBot 10:01, 10 November 2007 (UTC)[reply]

Change in pot. temp. with height

I take issue with the following statement:

"Under almost all circumstances, potential temperature increases upwards in the atmosphere,"

I think that this is partly correct, however under most circumstances I would think that potential temperature would not change with height. The atmosphere is unstable in most locations, and an unstable atmosphere with positive buoyancy of air parcels would result in a constant potential temperature with height. Should we maybe change this? Sean Egan (talk) 04:46, 19 June 2012 (UTC)[reply]

Importance of entropy in Potential Temperature

I think there should be some mention of the importance of potential temperature due to its conservation of entropy.

The main benefit of potential temperature is that entropy remains constant, and therefore we can use isentropic backtrajectory to calculate the origin/future paths of air parcels. Right? It's sort of stated in the article but it needs to be stated more clearly.

Sean Egan (talk) 04:59, 19 June 2012 (UTC)[reply]

I've added something on that with reference. Hoping that it answers your query. Pierre cb (talk) 16:24, 19 June 2012 (UTC)[reply]

Dimensions wrong

The equation must be wrong since the gas constant R and the heat capacity c_p have different dimensions.

I think the problem creeps in when dh is replaced with c_p dT when it should be c_p M dT where M is the molar mass in kg.

If you do this then the exponent ends up as R/(M.c_p) and everything works out alright.

I found this problem because I was trying to use the equation in this to derive the well known fact that the air column is stable if dT/dz stays above g/c_p. But whenever I used the equation shown in this article I always ended up out by a factor of the molar mass.

I'm not an expert so I'm adding a comment to the chat rather than directly editing the article.

Comments? Alzibub (talk) 15:48, 31 October 2021 (UTC)[reply]

I am confused by wording in the section 'Potential temperature perturbations'.

It states there that "This value is called the potential temperature deficit in the case of a katabatic flow, because the surface will always be colder than the free atmosphere and the PT perturbation will be negative".

My issue concerns "surface" and "colder"...

First, the context is clearly a discussion about the atmosphere, not the ocean; then, we are discussing the case of katabatic (downward) flow near the top of the ABL: a parcel of air from the free atmosphere above the ABL flowing down into the ABL. This would not happen if the PT perturbation were positive (which is the stability condition), so the perturbation must be negative... which is the conclusion reached. Fine.

But if the "surface" referred to is the top of the ABL, then a negative PT perturbation implies that that surface must be WARMER, not colder than the free atmosphere above.

So, am I confused, or should the word "colder" be replaced by "warmer"? DrTLesterThomas (talk) 19:22, 15 February 2025 (UTC)[reply]