<p>It depends on the season. The figures below shows zonal mean temperature for June-July-August <a href="http://old.ecmwf.int/research/era/ERA-40_Atlas/docs/section_D25/parameter_zmtsp.html" rel="nofollow noreferrer">from ECMWF ERA-40 reanalysis</a>.  As you can see, at 100 hPa, the equator is actually <em>colder</em> than the sunlit hemisphere.</p>

<h2>June-July-August</h2>

<p><img src="https://i.sstatic.net/nBQBX.gif" alt="Zonally averaged temperature"></p>

<h2>December-January-February</h2>

<p><img src="https://i.sstatic.net/fT5At.gif" alt="enter image description here"></p>

<p>For getting the "facts" on this kind of questions, the <a href="http://old.ecmwf.int/research/era/ERA-40_Atlas/docs/index.html" rel="nofollow noreferrer">ECMWF ERA-40 atlas</a> is a good source.  Now as to <em>why</em> this is the case; that is a much more involved question on atmospheric dynamics and circulation.  The Earth heats the surface, in particular where it's sunlit.  It also heats the spring and summer stratosphere, where ozone absorbs solar radiation.  Heating causes air to rise from the surface to the tropopause, where it's forced poleward creating a <a href="https://en.wikipedia.org/wiki/Hadley_cell" rel="nofollow noreferrer">Hadley cell</a>.  Meanwhile, the Earth rotates and everything becomes a highly chaotic and dynamical system.  So the fact that winds are strongest near the tropopause (see, for example, <a href="http://old.ecmwf.int/research/era/ERA-40_Atlas/images/full/D25_XS_DJF.gif" rel="nofollow noreferrer">DJF winds</a>) is not a direct consequence of where the heating occurs, but rather the effect of a lot of dynamics.</p>

<p>For further reading on why atmospheric circulation is as it is, one needs to study textbooks.  Some famous textbooks on dynamic meteorology and atmospheric science are:</p>

<ul>
<li><a href="http://books.google.ca/books/about/An_Introduction_to_Dynamic_Meteorology.html?id=fhW5oDv3EPsC" rel="nofollow noreferrer">James Holton, An Introduction to Dynamic Meteorology</a></li>
<li><a href="http://books.google.ca/books?id=HZ2wNtDOU0oC&amp;redir_esc=y" rel="nofollow noreferrer">Wallace &amp; Hobbs, Atmospheric Science: An Introductory Survey</a></li>
</ul>

CC BY-SA 3.0
2014-05-13T23:33:30.797Z
A number of your links appear to be broken, since the ECMWF site has updated to a new version or something.
senshin
CC BY-SA 3.0
2014-05-13T23:36:22.867Z
@senshin Good catch.  I've linked to the old site for now, will stop working in April 2015 though...
gerrit
CC BY-SA 3.0
2014-04-15T20:04:30.393Z
2014-05-13T23:36:02.877Z
2014-05-13T23:36:02.877Z
gerrit
<p>Are the pole-to-equator temperature gradients lower at higher heights than at lower heights (like 850 mb/500 mb)?</p>

<p>If so, why is it the case? Especially given that the zonal circulation tends to be much higher at higher heights, so one could expect there to be less <a href="https://en.wikipedia.org/wiki/Meridional_flow" rel="nofollow">meridional</a> heat transport.</p>

<p>(Bonus question: how is it different in other planetary atmospheres?)</p>

<atmosphere><meteorology><temperature>
How does the pole-to-equator temperature gradient scale with height contours?
InquilineKea
# How does the pole-to-equator temperature gradient scale with height contours?

(Asked by: username_0 on 2014-04-15)

Are the pole-to-equator temperature gradients lower at higher heights than at lower heights (like 850 mb/500 mb)?

If so, why is it the case? Especially given that the zonal circulation tends to be much higher at higher heights, so one could expect there to be less [meridional](https://en.wikipedia.org/wiki/Meridional_flow) heat transport.

(Bonus question: how is it different in other planetary atmospheres?)

**Tags:** atmosphere, meteorology, temperature


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## 1 answers

### Answer by username_1 on 2014-04-15. Score: 13 | Accepted answer

It depends on the season. The figures below shows zonal mean temperature for June-July-August [from ECMWF ERA-40 reanalysis](http://old.ecmwf.int/research/era/ERA-40_Atlas/docs/section_D25/parameter_zmtsp.html). As you can see, at 100 hPa, the equator is actually *colder* than the sunlit hemisphere.

## June-July-August

![Zonally averaged temperature](https://i.sstatic.net/nBQBX.gif)

## December-January-February

![enter image description here](https://i.sstatic.net/fT5At.gif)

For getting the "facts" on this kind of questions, the [ECMWF ERA-40 atlas](http://old.ecmwf.int/research/era/ERA-40_Atlas/docs/index.html) is a good source. Now as to *why* this is the case; that is a much more involved question on atmospheric dynamics and circulation. The Earth heats the surface, in particular where it's sunlit. It also heats the spring and summer stratosphere, where ozone absorbs solar radiation. Heating causes air to rise from the surface to the tropopause, where it's forced poleward creating a [Hadley cell](https://en.wikipedia.org/wiki/Hadley_cell). Meanwhile, the Earth rotates and everything becomes a highly chaotic and dynamical system. So the fact that winds are strongest near the tropopause (see, for example, [DJF winds](http://old.ecmwf.int/research/era/ERA-40_Atlas/images/full/D25_XS_DJF.gif)) is not a direct consequence of where the heating occurs, but rather the effect of a lot of dynamics.

For further reading on why atmospheric circulation is as it is, one needs to study textbooks. Some famous textbooks on dynamic meteorology and atmospheric science are:

* [James Holton, An Introduction to Dynamic Meteorology](http://books.google.ca/books/about/An_Introduction_to_Dynamic_Meteorology.html?id=fhW5oDv3EPsC)
* [Wallace & Hobbs, Atmospheric Science: An Introductory Survey](http://books.google.ca/books?id=HZ2wNtDOU0oC&redir_esc=y)

> **Comments:**
> **username_2**: A number of your links appear to be broken, since the ECMWF site has updated to a new version or something.  
> **username_1**: @username_2 Good catch.  I've linked to the old site for now, will stop working in April 2015 though...  

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