A Tale of Two Altitudes


Any serious discussion about the Theory of Global Warming will eventually include the absorption band argument that started more than 100 years ago between Arrhenius and Ångström.  One of the arguments presented by Ångström was that the main CO2 absorption band is between 14-16 micron and that band is also absorbed by water vapor (which is correct).  The counter to this by Arrhenius was that it didn’t matter in the upper atmosphere where there was no water vapor.  Of course none of this matters because radiative heat transfer is only 20% of the energy transferred to the atmosphere, but that is generally ignored by both sides of the argument.

At the time there was no way to measure the temperature in the upper atmosphere so there was no way to determine what was going on there, but of course now there are many ways to measure the temperature there.  When I started looking at the annual temperature behavior of the stratosphere and the top of the troposphere I found something very interesting that is as usual, bad for the warmists.

Here is the average daily temperature of the troposphere (at ~4.2 km) and the stratosphere (41 km).

The Inconvenient Skeptic

Daily average temperature of the: (Brown) Troposphere at 4.2km and (Blue) Stratosphere at 41km).

What makes this so interesting is that they are completely out of phase with each other.  The tropospheric temperature is matched to the natural global temperature cycle.  This is highly dependent on the geography of the Earth’s surface.  The stratospheric temperature is not in phase at all with the surface temperature.  It is however in phase with the Earth’s orbit around the Sun.  The distance the Earth is from the Sun determines how much energy the Earth gets from the Sun.  Here is the stratospheric temperature and the solar constant over the course of the year.

The Inconvenient Skeptic

Stratospheric temperature is dependent on the solar constant and not the lower atmosphere's temperature. (Orange) Solar Cosntant. (Blue) Stratospheric Temperature.

While I would not say that the upper atmospheric temperature is completely independent, it is mostly independent of the of the lower atmosphere.  The cooling in the stratosphere each spring is exactly what would be expected based on the changing solar constant.  The warming that takes place in July is likely caused by the peak atmospheric temperatures in the NH that take place during the summer months.  That warming stops in October, but by that point the increasing solar constant warms the stratosphere.

What determines the stratospheric temperature is absolutely critical to understanding why it has been cooling over the past 60 years (which is about how long it’s temperature has been measured).  If the stratosphere’s temperature is primarily dictated by the incoming solar energy then the argument made by Arrhenius is meaningless.  That is because the increase in CO2 would never have an impact on the temperature there, simply because so little of the energy needed to warm the stratosphere comes from the Earth’s surface.

Based on the scientific data, the stratosphere is mostly influenced by the solar constant (basically the distance from the Sun for this discussion).  There appears to be some influence from the lower atmosphere, but it is clearly marginal.  This is not really a surprise since the energy transfer mechanisms are very limited above 12km.  The low atmospheric density results in low vertical mixing rates which only leaves radiative transfer which is a poor method for heat transfer when low absolute temperatures are involved.

When the temperature of the stratosphere and the troposphere are compared for the period from 2003-2011 it is also interesting to note that the peak stratospheric temperature was lowest of the whole period in early 2009.  This also matches the period of minimal solar activity over the entire period of time.  All of these pieces together clearly demonstrate the importance of the solar constant on the stratospheric temperature.  This also means that any impact by atmospheric CO2 levels on the stratospheric temperatures is very limited.

The Inconvenient Skeptic

Tropospheric and Stratospheric temperatures from 2003-2011

Total Solar Insolation

Posted in Climate and Science Overviews by inconvenientskeptic on April 29th, 2012 at 9:28 pm.

16 comments

This post has 16 comments

  1. Colin Aldridge Apr 30th 2012

    1.Is this synching of the stratospheric temperature with Solar distance generally accepted and
    2. Why is this bad news for warmists.

  2. inconvenientskeptic Apr 30th 2012

    Colin,

    I have not seen any other explanation for the de-coupled stratospheric temperatures, but I also have not seen many people discussing this topic.

    It is bad news for warmists because one of the foundations of global warming is that increasing the CO2 in the upper atmosphere is supposed to the primary mechanism of back-radiation that causes the feedback.. This is because the water vapor in the lower atmosphere interferes with the absorption band of CO2.

    The whole upper atmosphere part has always been a weak argument, but the fact that the temperature is independent of the lower atmosphere is a wrecking ball on the upper atmosphere theory.

  3. AndyG55 Apr 30th 2012

    Being that the troposhere is warmest in June, I’m assuming this comparison is done somewhere in the northern hemisphere ??

    Or is it a global average.. which would mean that it is highly biased toward the NH?

    Sorry, just a bit puzzled..

    If it is NH data.. what do SH graphs look like ??

  4. inconvenientskeptic Apr 30th 2012

    This is global average temperature.

    I don’t yet have raw daily temperature data by hemisphere for the stratosphere.

  5. AndyG55 Apr 30th 2012

    They my assumption would be that the greater land mass in the NH is biasing the result so its maximum is in June. ie the much greater sea area in the SH regulates the temperture of the SH during the HN winter. (sorry, just trying to figure out why a GLOBAL average should have a peak in the HN summer.)

    The troposhere warming in that peaks in June would push up the height of the tropopause, I think, and something like this might happen ….

    http://members.optusnet.com.au/~gradds55/Stratocooling.jpg

    which would explain the inversion of the graphs.

    Sorry, not arguing, just trying to get this into my skull !! 🙂

  6. inconvenientskeptic Apr 30th 2012

    Andy,

    You are correct. The Earth’s surface experiences the maximum temperature as a direct result of the NH summer and the coldest period with the NH winter. This is due to the difference in geography between the two hemispheres.

    That the stratosphere doesn’t show that behavior indicates that different forces control it’s cycle. What matches is the total daily energy. Since the Sun is mostly constant, that variation is due to the orbit.

  7. Richard111 May 1st 2012

    All good stuff to stir up the brain cells. Thanks John. Now to add more wotsits 🙂 isn’t the Earth closer to the sun during SH summer period? This will mostly effect the ‘deep heat’ in the oceans I think. And ocean heat transport is rather more effective than atmospheric heat transport, at least across the equator. Ach! Now I’m confusing myself trying to think while I type.

  8. inconvenientskeptic May 1st 2012

    Contrary to popular belief both the NH and SH oceans warm up immensely during the respective summer seasons, but only the surface water. Most of the heating takes place in the top 60m of ocean and then that water cools the following winter.

    Not a lot of energy crosses the equator from what I have seen. Energy from the each side of the equator tends to flow towards the poles in both hemispheres in the ocean and the atmosphere.

  9. Eric Anderson May 8th 2012

    AndyG55: “which would explain the inversion of the graphs.”

    No. It would explain why the troposphere temperature peaks in July-August (assuming a few weeks lag in temperature maximums from the NH summer solstice), but you would not have a near half-year offset in the stratosphere temperature due to an increase in height of the tropopause. Also, the troposphere temperature peak follows in time the stratosphere temperature trough, rather than leading it, so it can’t be causing it.

    The stratosphere measurement seems to closely correlate with insolation, which is greatest in January when the Earth is closest to the Sun.

    I’m interested, however, in your comment about the increase in the height of the tropopause. Just wondering how, or if, that would affect the temperature measurement at a constant 41km up . . . Anyone have any thoughts?

  10. Eric Anderson May 8th 2012

    Incidentally, John, thanks for sharing this. I hadn’t seen the stratosphere temperature measurement compared with the troposphere or the solar constant before. Very interesting and, potentially, a very important piece of information.

  11. AndyG55 May 8th 2012

    What i would like to see is the full height graph of measurements, not just one in the troposphere and one in the stratosphere, at set heights.

    I still think that the change in height of the tropopause and the fact that there is a positive temperature gradient above that would explain the inversion of the graphs.

    full height data please, not just 2 set heights.

  12. AndyG55 May 8th 2012

    ps.. or at least full height temperature profiles for say January and June… that would be enough

  13. inconvenientskeptic May 8th 2012

    I will try to get something put together since this topic has interested people. I wasn’t sure it would do that. 😉

  14. AndyG55 May 8th 2012

    Eric , if the tropopause is always at about the same temperature (is it?, if so, why?) and changes height due to temperture below it,…. the since there is a negative lapse below the tropopause and a positive lapse above the tropopause, then it make sense that the 40km reading would get colder as the 4km reading gets warmer. The question is, does a point at the same distance above the tropopause get colder.?

    I can see there appears to be an offset of some sort,
    again, why?. The tropopause can be a wide band, maybe it has some elesticity as it changes height, which could cause the offset.
    I can see that there is also a coincidence with the solar value.?

    But what is causing what?

    just trying to get a handle on this is all…

  15. AndyG55 May 8th 2012

    elasticity.. darn typoing !!

  16. Eric Anderson May 10th 2012

    AndyG55:

    Excellent questions, and I certainly don’t have all the answers. Just trying to think through things as well.

    I was focusing on the fact that the 41km temperature starts a deep decline and hits its lowest temperature *before* the 4km temperature reaches its maximum. I agree with your point that the increased height of the tropopause could, potentially, affect the 41km temperature (assuming the stratospheric bands also increase in height correspondingly). However, the timing wouldn’t make sense, because the “cause” would precede the effect.

    Seems that a more simple answer is that the 41km temperature is affected primarily (if not exclusively) by the insolation. And, similarly, the 4km temperature is also affected primarily (if not exclusively) by insolation as it interacts with the greater land surface than ocean (i.e., greater NH land surface than SH). If this is the case, then the regular and relatively straight-forward insolation variance throughout the year would neatly explain both cycles as a natural process, withouth need to resort to additional mechanisms or to postulate unnatural (e.g., human) influence on the temperatures.

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