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How Jo Nova doesn't get the tropospheric hot spot

Posted on 19 June 2010 by John Cook

Climate models predict that during global warming, the lower atmosphere in the tropics should warm faster than the surface. This phenomenon has been coined the 'tropospheric hot spot'. Unfortunately, that elusive hot spot has been devilishly hard to measure. Both satellites and weather balloons have previously found the warming trend in the tropical troposphere is roughly the same as (or even less than) surface warming. The Skeptics Handbook, published by Jo Nova, labels this a "knockout blow" to human caused global warming.

The biggest misunderstanding about the tropospheric hot spot is the mistaken notion that it's caused by the greenhouse effect. Jo Nova leads with the headline "The greenhouse effect is missing" and refers to the "telltale warming pattern that greenhouse gases would leave". However, the hot spot is not caused by the greenhouse effect. In fact, we expect to see an amplified warming trend in the troposphere no matter what's causing the warming.

The hotspot is actually due to a basic law of physics called the moist adiabatic lapse rate. As air rises to higher altitudes, it cools. When the water vapor in the air cools enough to condense, latent heat is released - this partly offsets the cooling. In the tropics where the air is more moist, more heat is released. The result is we expect to see magnified warming trends in the troposphere compared to the surface, both over short intervals (say months to a year) and long intervals (over decades). Indeed over short periods, observations are consistent with expectations - a tropical hot spot:


Figure 1: Ratio between atmospheric temperature compared surface temperature at different altitudes. Colour lines are various model results. Thick black line is theoretical value. Thin black line is weather balloon measurements from RATPAC. Dashed line is weather balloon measurements from HadAT2 (Santer 2005).

So short-term trends confirm the moist adiabatic lapse rate. However, when we look at long-term trends, satellites and weather balloons have trouble detecting the magnified trend. Why? A likely answer is measurement uncertainty. Satellite measurements are subject to long-term biases caused by orbital decay and the cooling stratosphere. Weather balloon data comes with it's own host of uncertainties. We have few balloon measurements in the tropics, there's been many changes of instruments and there are known biases due to solar heating. A number of teams have used different techniques to account for the biases affecting weather balloon data. The various methods find a similar result - when the biases are adjusted for, the result is closer to the expected moist adiabatic amplification (Titchner 2009, Sherwood 2008, Haimberger 2008).


Figure 2: Bias-corrected weather balloon temperature trend vs pressure over the tropics from 1959 to 2005 (Sherwood 2008).

Independent evidence for the hot spot comes from measurements of wind trends, which aren't subject to the same biases as weather balloon temperature measurements. As there's a direct relationship between temperature gradients and wind shear, this allows calculation of temperature trends from wind data. What is found is a peak warmer trend in the upper troposphere, consistent with climate model simulations (Allen 2008).

That's not to say everything is hunky dory with tropospheric trends. Satellites still show tropospheric trends less than expected, although the RSS trend is broadly consistent with expectations. And there is still much uncertainty in the weather balloon data.

Nevertheless, there are several key points to remember. Detecting the tropospheric hot spot is not a test of the greenhouse effect but of the moist adiabatic lapse rate. Data uncertainty and long-term biases mean detection of the hot spot has been difficult. Nevertheless, there is evidence that the hot spot exists. But if you cannot accept this evidence, to be strictly correct, what you are is a moist adiabatic lapse rate skeptic.

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Comments

Comments 1 to 43:

  1. Same principle applies to cooling (granite) plutons...there referred to as crystallisation heat.

    Derek, FoGT
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  2. It's worth pointing out that radiosondes were never meant for climate work, but like surface stations, were deployed to gather data for improved weather forecasting.

    "Close enough for horseshoes, hand grenades, and weather forecasting" ...

    This particular misunderstanding of the meaning of the "tropospheric hot spot" has been explained so endlessly that Jo Nova has to be intentionally misleading people.
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  3. This treatment is missing some clarity I think. Tropospheric amplification (relative to the surface) means that the lapse rate is itself changing, due to changes in humidity.

    I see it written here that there is a lapse rate, and that dry and moist lapse rates are different from each other. What I don't see here is a discussion of why the observed lapse rates would change over time.
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  4. I second carrot eater´s question. A trend is mentioned, but I failed to understand what causes it. Is there any projection about the hot spot trend as a response to AGW?
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  5. Alexandre,
    AGW has nothing to do with it, in particular.

    If the surface warms, regardless of why, there should be somewhat amplified warming in the troposphere. If the surface cools, regardless of why, there should be somewhat amplified cooling in the troposphere.

    On a perhaps simplistic level: If the lapse rate did not change, then the troposphere and surface would warm or cool at the same rate as each other. But with some warming, the absolute humidity of the air can increase, and this will change the observed lapse rates, due to the moisture effects mentioned above. If the lapse rate is changing over time, then the trends at the surface will be different from the trends further up.

    Take that as a rough sketch, but I hope nothing is fundamentally wrong there. If there is, others will jump in.
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  6. Chris Colose had a nice post on this awhile back.

    Skeptics/Denialists Part 2: Hotspots and Repetition

    He mentions that lack of a tropical tropospheric hotspot (assuming the questionable studies that claimed this were correct) would likely imply a greater climate sensitivity. Any comments on that aspect?
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  7. Great post John and like always I enjoy learning from your site.

    For a long time now I've been struggling with the reason why so many intelligent, well meaning people can't seem to come to the same conclusion with regard to AGW. And based on the people who post on this site I lump roughly 90% of them into that category of general truth seekers and not those on the fringe who only have an interest in confrontation and 'winning' the argument. While reading this article, it has occurred to me that the complexities of Climate Science are so daunting and our understanding of it so in its infancy that we lack the rock-solid data to prove without a shadow of a doubt one side of the argument or the other. I thought the one solid measurement upon which we could agree was OLR but obviously from John's article and the Science of Doom article there is still plenty to debate with regard to measurements and interpretations of OLR reduction due to CO2. Surface temperatures are erroneous and biased by UHI, proxy data are questioned, satellite data is questioned (in this posting), etc. It seems that both sides are 'skeptical' when it comes to measured data that don't support their position. When will this end? When climate science has advanced far enough where the models are complete and account for things such as clouds, aerosols and other variables that are poorly understood? When, after decades, these AGW predictions don't materialize? I have yet to see data in support of a position on either side of the AGW debate go unquestioned. I welcome links to papers/articles that the community feel meet that lofty goal.
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  8. NewYorkJ: I think that's a good question because a 'real' skeptic might conclude from this discussion: no tropospheric hotspot thus no change in adiabatic lapse rate. So apparently the surface hasn't warmed -> see, the surface temperature measurements are all flawed and scientists are just suffering from confirmation bias, or worse; fraud!
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  9. "I have yet to see data in support of a position on either side of the AGW debate go unquestioned."
    And you likely never will. Personally I look at what evidence stands up to the questioning and scrutiny rather than calling it a wash because it is all questionable in some way. To each his own, I suppose.
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  10. Gary, it might help your understanding to carefully consider what is implied by "questioning the data." Many of these questions resolve to doubt without substantial justification for that doubt. UHI is s great example of that phenomenon.

    Published scientific literature is the most useful refuge from confusion. The farther you go from the journals, the more pointless noise you're going to encounter.
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  11. Good post. Perhaps I can shed some more light on the question by NewYorkJ in reference to my article.

    The lapse-rate feedback is defined as the difference between total-temperature feedback and surface-temperature feedback. It is thus a measure of how the radiative budget is perturbed by shifting the vertical thermal structure of the atmosphere. In the isothermal limit where the temperatures aloft are the same as the ground temperature, there is no greenhouse effect and the planet's emission must satisfy equality with the absorbed incoming solar flux. As the atmospheric opacity increases, the atmospheric/surface temperature gradient will increase, with the TOA/surface temperature ratio approaching zero as the atmospheric opacity approaches infinity.

    As the globe warms, the tropical temperature gradient between the surface and free atmosphere must decrease, and consequently, emission increase from upper layers of the atmosphere providing a negative feedback. The situation is reversed at the poles where the low-level anomalies tend to be amplified relative to the free atmosphere since water vapor is so low and surface albedo feedbacks dominate. This thus provides a local positive lapse rate feedback. If the tropics behaved analogously and the upper atmosphere was not amplified relative to the surface, then the lapse rate could only be less negative (or even positive). Note that cynicus' comment does not really make sense in this regard, because the surface can warm independently of the lapse rate. The lapse rate just sets the difference in temperatures between the surface and layers aloft, it says nothing about the absolute temperature at any point.

    In models however, those models with the greatest reduction in outgoing radiation from water vapor also produce the greatest enhancement of emission aloft from temperature feedback (in the tropics). This is the definition of the so-called "hotspot" and it has nothing to do with the direct increase in CO2. For those still not convinced that the lapse rate is intimately connected with water vapor (and thus the WV feedback), you can see from the following diagram that, interestingly, the uncertainty in the WV+LR feedback is actually much smaller than the uncertainties in either the WV or LR feedback considered individually.



    Because of this connection it is quite common to consider the WV+LR feedback collectively. So the hotspot is indeed due to the moist adiabat, and the lack of such amplification is neither a disproof of anthropogenic global warming, nor is an argument against a high sensitivity.

    In some exotic cases, it is conceivable that greenhouse gases themselves can alter the thermal structure of the atmosphere in such a way as to produce a large reduction to the greenhouse effect in condensation. This might happen for example in an atmosphere that was strongly absorbing to incoming solar radiation. If you replace radiation at incident at the surface with radiation absorbed aloft, you can generate an anti-greenhouse effect and make a deep layer that is nearly isothermal. It is thought that if the ratio of methane to CO2 concentrations approaches one, you can get a "haze layer" that absorbs solar radiation in the upper atmosphere and radiates it back to space, whilst cooling the surface. This has implications for early Earth evolution. In the modern however, water vapor does absorb some solar radiation and is dominant in the lower atmosphere where humidity is greatest and the polar regions where you have a good chance of absorbing upwelling photons from high albedo. This shortwave component of the water vapor feedback is positive by causing an increase in shortwave absorption and accounts for about 15% of the total water vapor feedback.
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  12. "we lack the rock-solid data to prove without a shadow of a doubt one side of the argument or the other"

    Science never claims anything to be 100% proven. Uncertainty is always admittedly, explicitly part of the picture. Doubt about science is easy to manufacture.

    Is the science settled?

    Doubt mongering works
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  13. Chris Colose #11

    I´m trying my best to grasp your explanation here and on the Climate Change blog, but my steps forward are still short.

    One particular issue seems to be important, and I could not understand it: why is it that the GHE depends on the lapse rate?

    It´s quite difficult to me to try to imagine an atmosphere without a lapse rate, but it would seem to me that this uniformly warm fluid would have downward radiation and GHE as well...

    What am I missing?
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  14. I'm missing something too, or being particularly thick today. Can John and/or Chris explain why the "tropospheric hot spot" (which in itself is a funny term, shouldn't it be layer rather than spot?) should change with global warming, and how it changes (higher, stronger, thicker?) as the surface warms. The implication of the "moist adiabatic lapse rate skeptic" is that someone is doubting the process, I can (I think) understand the process, what I can't understand is how it relates to global warming.
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  15. Alexandre, you are right that it's hard to imagine a strictly isothermal atmosphere, although a very weak lapse rate is important for the dynamics of the winter hemisphere in a snowball Earth, or winter-time in Mars, but the hypothetical example is only used to illustrate the importance of the vertical temperature structure of the atmosphere in general. This is useful for not only understanding the GHE but interpretation of outgoing spectra.

    Consider the following diagram from Petty's book (which John Cook also used here in discussing the paper I helped co-author with Halpern et al. for the G&T rebuttal):



    What you're seeing in the top figure is the outgoing radiation from a sensor looking down at the Earth (or looking down at 20 km, which is almost the same thing). In the atmospheric window (from about 800 to 1000 inverse centimeters, with wave number being the dimension on the x-axis) the sensor is seeing emission from the surface and lowermost atmosphere, since there is little absorption by atmospheric gases in this spectral region. Thus the emission follows relatively smoothly along the dotted Planck emission line corresponding to the warmest temperatures at the bottom of the atmosphere. In the optically thick regions, such as between 600 and 800 inverse centimeters where the CO2 has strong absorption, the emission is only being detected from the colder layers of the atmosphere. For example, the center of the CO2 band is following along the 225 K Planck emission line. Consider the case where you are situated in a region with a temperature inversion, which is a persistent feature in polar winter for example:

    http://www.sundogpublishing.com/fig8-3ab.pdf (it's a PDF file so I cannot readily display the image via HTML, see bottom graph for the Antarctic ice sheet). Here the temperature is increasing with height in the atmosphere. Now you're still seeing emission from the surface in the window regions. In the CO2 band the emission aloft is coming from warmer areas, and so the CO2 is actually producing somewhat of a "negative greenhouse effect."

    If the planet had no atmosphere with a blackbody surface you would see a smooth emission spectrum at ~255 K (assuming present-day albedo). In the typical case where the temperature declines with height, what the greenhouse gases are doing is taking a bite out the Planck spectrum, and so the total area beneath the curve is reduced, which means the planets emission is reduced. This therefore reduces the emissivity of the planet and so it must heat up until the temperature is such that the area under the Planck curve is the same as before (i.e., it balances the incoming stellar flux). This occurs because increasing the temperature of a body increases the intensity at all wave numbers and so the total area under the Planck curve increases.

    But in order for this "bite" to occur from the CO2 band, the sensor must be looking at emission from a different temperature than the surface. If the whole atmosphere were of uniform temperature, then the emission spectrum the sensor records would simply follow that temperature, and one could make no distinction as to whether or not the emission was coming from the surface or aloft. Since the area under the Planck curve would not change, you would not change the temperature by absorbing more of the outgoing energy. Even if the atmosphere were so optically thick that emission were coming from the uppermost layers, those layers are the surface temperature in the isothermal limit, so top-of-atmosphere radiation balance requires equilibrium with the absorbed solar energy at that temperature.

    By the way, there again are some exotic cases. On planets where you can get CO2 clouds or other very effective infrared scattering, you can get a greenhouse effect through IR scattering rather than through traditional absorption and re-radiation. This could produce a greenhouse effect regardless of the temperature profile. This may have been a big part of getting Early Mars above freezing.

    Re David Horton. Consider this image:



    Here we see three curves which correspond to three hypothetical and idealized temperature profiles. Lines "A" and "B" are the same slope, the only difference is the intercept of the curve, so that the absolute temperature at any height in "B" is warmer than in case "A" (Say, that planet absorbs more solar energy but has the same lapse rate). However, in a global warming situation (in the tropics) we expect the adjustment to look something more like the transition from "B" to "C."

    In this case, not only do you get temperature rise at the surface, but the slope of the adiabat changes in such a way as to produce amplification aloft. If you're looking for a more detailed contour plot that shows the temperature change with height and with latitude, here is a simulation for 2xCO2.
    http://data.giss.nasa.gov/efficacy/Rc_pj.1.06.html

    All of a sudden this change of slope in the adiabat becomes a feedback, because now the air at any given altitude (now at a warmer temperature) would radiate more energy to space. This partially offsets the water vapor absorbing effect.

    Hope that helps
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  16. Gary-to say that anything in science is 100% certain is to betray an ignorance of science. If we only accepted those things we were 100% certain of, then we'd still be living in the Dark Ages! I've worked as a scientist for some 15 years now, in a number of non-controversial fields, & I've yet to come across any where our body of knowledge was based on 100% certainty-or even 90%. Yet this *only* seems to be an issue in Climate Science-WHY?!?!
    The inability to detect a Tropospheric Hot Spot doesn't-by itself-negate the existence of AGW because, as John & Chris have rightly pointed out, this Hot Spot is supposed to exist independent of Global Warming. So our inability to detect it could simply be the result of (a) an incomplete understanding of how this effect responds to a warming climate or (b) a lack of instruments sensitive enough to detect it. Even if the Tropospheric Hot Spot is proven to *not* exist (as unlikely as that might seem), we'd still have more than 100 years of knowledge about how certain gases contribute to the planet's natural energy balance-& how they might contribute to an energy *imbalance*-combined with a strong correlation between near-surface/tropospheric warming & rising CO2-in the absence of rising solar activity; the reduction in detectable outgoing IR radiation & the cooling of the stratosphere. All of which are very consistent with an enhanced Greenhouse Effect being the most likely contributor to global warming over the past 60 years. What Jo Nova-& yourself-are promoting is what is referred to as "manufactured uncertainty"-which is directly antithetical to scientific endeavor IMO.
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  17. By the way, another community very interested in this "hotspot" stuff is the hurricane people, since hurricane strength is a function of SST and the upper level outflow areas. One issue brought up in the recent RealClimate article (in the comments) was stratospheric cooling and its influence on the uptick of tropical cyclones. Similarly, studies have pointed out that you can get more storms by reducing the moist stability of the atmosphere (i.e., by getting rid of the amplification in the upper atmosphere.) See e.g.,

    T. R. Knutson, J. J. Sirutis, S.T. Garner, G. A,. Vecchi, and I. M. Held, 2008: Simulated reduction in Atlantic hurricane frequency under twenty-first century warming conditions, Nature Geosciences, doi:10.1038/ngeo202
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  18. Re the limits of scientific certainty, a recent essay in the Economist (copy here) had an interesting take on how different audiences weigh evidence:

    “In any complex scientific picture of the world there will be gaps, misperceptions and mistakes. Whether your impression is dominated by the whole or the holes will depend on your attitude to the project at hand. You might say that some see a jigsaw where others see a house of cards. [Climate scientists] have in mind an overall picture and are open to bits being taken out, moved around or abandoned should they not fit. Those who see houses of cards [deniers] think that if any piece is removed, the whole lot falls down.”
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  19. Having spent some time over at Jo Nova's site trying to rebut at least some of the more outlandish claims, I can tell you it is a very frustrating experience. But here afficionado's lap it up.

    For example, SHB 1 doesn't 'get' the hotspot, doesn't get how wind shear could actually be a valid method. Why can't you just rely on the thermometers. Then in SHB 2, she rolls out A Watts and the SurfaceStations.org stuff. We can't trust the thermometers because of site specific influences. But we should trust the thermometers on the radiosondes. No site specific influences there.. Then the real howler. Right there on the graphs of the missing or not hotspot is another signature of AGW - Stratospheric Cooling. No comment on that one.

    Also we have the deep historical record of CO2 vs Temps, 500 MYrs worth and NO CORRELATION. Apart from the lack of mention of long term solar output changes. David Archibalds Bar Chart of Temp vs CO2 per 20 ppm and there 'isn't much effect left'. Without connecting the dots... Solar Increase with time explains the deep historical record when CO2 was MUCH higher...Therefore, more CO2 obviously does have an affect for many doublings to come.

    Jo argues that the debate is about the magnitude of feedbacks and climate sensitivity, which it is. But her 'handbooks' drag in a lot of old tired denialist rubbish arguments as well. Sceptics Handbooks they ain't. Denialist recruiting manuals? well...

    Be careful John. Take on Jo and some of her followers will probably come calling. Or she will probably call you all sorts of bad names. Just ask Andrew Glickson or Stephan Lewandowsky.

    On another note, relating to finding the hotspot, and also an analysis of the satellite data, particularly UAH, this paper is interesting.

    http://www.ncdc.noaa.gov/oa/climate/research/nature02524-UW-MSU.pdf

    By Fu et al, written a year or so after the major discrepancy between the satellite and surface data was resolved in the early naughties. They argue that the T2 temperature record from the satellite data, the troposphere, is prone to 'contamination' from part of the temperature reported being due in part to the lower stratosphere. With startospheric cooling, this may be biasing temp records for the troposphere down. They are critical of the T2LT series from UAH which is often used by sceptics. This was produced to try and compensate for the 'bleed' from the stratospheric data and they feel the methods used are not reliable.

    They present an alternate strategy, using Radiosonde data to try and get a temperature profile vertically and use this to produce a weighted combination of T2 (troposphere) data less some of the T4 (lower stratosphere) data to factor out the stratospheric cooling effect. They then apply this to both UAH & RSS series, producing an adjusted set of trends.

    The interesting item to note is Fig 3. Their adjusted trend for the RSS data shows a clear difference between the Surface and the Troposphere for both Tropics & Southern Hemisphere. There is the 'hotspot'.
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  20. Chris Colose #15

    Thank you very much for your response. Now I think I understood it: without a lapse rate, you cannot "see" other temperatures from the top of the atmosphere, so there would be no GHG "bite" in the OLR spctrum.

    So if the hotspot were not there, then the lapse rate would be probably greater (greater temperature drop with altitude), and hence the intuitive conclusion that the climate sensitiviy would also be greater. Thanks.
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  21. A more accurate way of phrasing poptech's synopsis might be "The failure of a warming trend that is entirely consistent with model results has been shown in various papers..."

    A minor quibble, based on other folks such as McLean et al attempting to explain measured temperature anomalies in the tropics via SOA and other means. My point being, if there's no noticeable warming trend in the tropics it's hard to say why McLean would need to be creating alternative explanations for why there's a multi-decadal anomaly in tropic temperatures.

    Incoherence.
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  22. Poptech,
    notice the word "submitted" on two of those papers... notice how its not "accepted"
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  23. How are those papers "devastating," poptech? Here's the conclusion of John's post:

    Detecting the tropospheric hot spot is not a test of the greenhouse effect but of the moist adiabatic lapse rate. Data uncertainty and long-term biases mean detection of the hot spot has been difficult. Nevertheless, there is evidence that the hot spot exists. But if you cannot accept this evidence, to be strictly correct, what you are is a moist adiabatic lapse rate skeptic.

    You've seized an opportunity to highlight some material contradicting McLean and other climate researchers, but I don't see how your argument is "devastating" to John's summary. Can you explain?
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  24. I compiled this list of papers, with the relevent quotes, that detect enhanced tropical troposphere warming within observations. Two are analysese of radiosonde temperature data, one is based on the thermal wind data, and two are based on the satellite MSU data.

    "In the tropical upper troposphere, where the predicted amplification of surface trends is largest, there is no
    significant discrepancy between trends from RICH–RAOBCORE version 1.4 and the range of temperature trends from climate models. This result directly contradicts the conclusions of a recent paper by Douglass et al. (2007)."
    http://ams.allenpress.com/archive/1520-0442/21/18/pdf/i1520-0442-21-18-4587.pdf

    "Insofar as the vertical distributions shown in Fig. 3 are very close to moist adiabatic, as for example predicted by GCMs (Fig. 6), this suggests a systematic bias in at least one MSU channel that has not been fully removed by either group [RSS & UAH]."
    http://web.science.unsw.edu.au/~stevensherwood/sondeanal.pdf

    "The observations at the surface and in the troposphere are consistent with climate model simulations. At middle and high latitudes in the Northern Hemisphere, the zonally averaged temperature at the surface increased faster than in the troposphere while at low latitudes of both hemispheres the temperature increased more slowly at the surface than in the troposphere."
    http://www.nature.com/ngeo/journal/v1/n6/abs/ngeo208.html

    "We find that tropospheric temperature trends in the tropics are greater than the surface warming and increase with height."
    http://www.atmos.washington.edu/~qfu/Publications/grl.fu.2005.pdf

    "At middle and high latitudes in the Northern Hemisphere, the zonally averaged temperature at the surface increased faster than in the troposphere while at low latitudes of both hemispheres the temperature increased more slowly at the surface than in the troposphere."
    http://www.atmos.umd.edu/~kostya/Pdf/VinnikovEtAlTempTrends2005JD006392.pdf
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  25. "satellites and weather balloons have trouble detecting the magnified trend"

    It's a strange choice of words. It sort of sort of suggests that the magnified trend is there it's just that we fail to detect it. Really if you were being balanced here you would say we have looked with the best technology possible and detected no long term warming, followed by the caveats you mention. This may seem trivial but it's the sort of thing that worries me about climate science. It comes under the category of concluding too much from the data. This was discussed a little in a previous post about Scafetta's work. It's something I see in peer-reviewed work on both sides of the arguement.

    "But if you cannot accept this evidence, to be strictly correct, what you are is a moist adiabatic lapse rate skeptic."

    ......or you wish to critically assess the information in front of you. Again it seems a fine and proper thing do when it's Scafetta's work but tainted with irrationalism and oil money when directed at others.

    "A number of teams have used different techniques to account for the biases affecting weather balloon data. The various methods find a similar result - when the biases are adjusted for, the result is closer to the expected moist adiabatic amplification (Titchner 2009, Sherwood 2008, Haimberger 2008)."

    I don't have time to read these paper so I'll just ask a question. Again in relation to Riccardo's recent post. He seemed to dismiss Scafetta's mathematical trick by showing his own trick could be used to generate just about any result he wanted. Wouldn't it also be the case that these 3 mathematical tricks could probably generate any result you wish. It all depends on what are your initial assuptions about the data?
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  26. Gee, I think I understand how Jo Nova got it so wrong. Let's see... satellites have trouble reflecting what the models predict. So the sat data must be wrong. Weather ballons are wrong too. But the wind, steady reliable, proves the models supporting AGW are right. Furthermore, when the sat and ballons don't support the models, they also don't detract from AGW theory. But when ANY data is ...what was the term? "adjusted for" well, then it does support the models and hence support the theory of AGW. Yep, I've got it. How could Jo Nova get it so wrong?
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  27. #29: "Gee, I think I understand ..."

    Might be easier to understand if you actually read the post before commenting.

    the hot spot is not caused by the greenhouse effect. In fact, we expect to see an amplified warming trend in the troposphere no matter what's causing the warming. ... Detecting the tropospheric hot spot is not a test of the greenhouse effect but of the moist adiabatic lapse rate.

    Most folks would agree that its better to do some research before forming opinions. SkS has a search feature; try it, you might like it.
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  28. Schnorkel
    dismissing a complex issue with innuendo brings us nowhere. You can find a good historical perspective here.
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  29. Ricardo and Mouncounter
    Took your advice on board and re-read Thorne et al again. But was puzzled not to see any reference to relevant literature in this meta-review, i.e. no mention of Christy et al ("What Do Observational Datasets Say about Modeled Tropospheric Temperature Trends since 1979?") in Remote Sensing 2010, 2, 2148-2169; doi:10.3390/rs2092148.

    Nor could I see any reference within to McKitrick et al's paper "Panel and Multivariate Methods for Tests of
    Trend Equivalence in Climate Data Series" in Atmospheric Science Letters.

    Or should we just say Christy and McKitrick don't count? That doesn't look good. Surely we can engage the sceptics on their own ground. We risk being seen as too timid to robustly confront contrary arguments.

    I mean, its sort of like Thorne et al just ignored people saying stuff they didn't like and focussed on the work of people who agreed with them, like Santer.

    It makes me think the Thorne meta-review paper you referred me to risks being seen as an attempt to get around the problem that the warming in the upper troposphere which the computer models tell us should be there, is really not there. Also I think that sceptics could see the use of the 'adiabatic' term and the "adjustments" terms as just another way to wriggle out of what they would say is the fact that human-induced climate change's hot spot is away on vacation.

    Surely we can do better than this.
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  30. Schnorkel.

    Those papers you mention were published barely 2 months before the Thorne review was published. There are often journal rules about making substantial changes to papers late in the production process. It's likely those papers appeared too late to be included.

    It's not as if Thorne doesn't quote Christy. I count 31 citations of papers with Christy as coauthor.

    I think you can (and should) do better.
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  31. Great site you have here, load of reading for me..
    Pardon the next question. I am just confused with terminology.
    This page states

    "The biggest misunderstanding about the tropospheric hot spot is the mistaken notion that it's caused by the greenhouse effect."

    I thought the greenhouse effect/greenhouse forcing was was
    1/the same thing.
    2/At the heart of AGWarming science.
    If its not, why is the ipcc using the term as well as the australian govt.?


    Greenhouse gas forcing is expected to produce warming in the troposphere
    http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch9s9-2-2.html

    Such “fingerprints of greenhouse gas forcing” include, for example, the observation that winters are warming more rapidly than summers and that overnight minimum temperatures have risen more rapidly than daytime maximum temperatures (IPCC 2007a)An apparent inconsistency between observations with greenhouse theory was the alleged failure to find a so-called “tropical hot spot”, a warming in the tropical atmosphere about 10-15 km above the Earth’s surface. In reality, there was no inconsistency between observed and modelled changes in tropical upper tropospheric temperatures, allowing for uncertainties in observations and large internal variability in temperature in the region. Furthermore, recent thermal wind calculations have indeed shown greater warming in the region (Allen and Sherwood 2008), confirming that there is no inconsistency and providing another fingerprint of enhanced greenhouse forcing.
    http://climatecommission.govspace.gov.au/files/2011/05/4108-CC-Science-Update-PRINT-CHANGES.pdf
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  32. mike, my understanding is that warming from any forcing would produce the tropospheric hotspot, its not a particular fingerprint of GHG warming. The alleged missing hot spot (not) is an item because of supposed inconsistancy between models and observations. As has been pointed out though, it is detection that is the problem, though there could also be issues in the model detail.
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  33. mike williams @34, the sentence you quote is poorly phrased. As the current warming is predominantly due to the enhanced greenhouse effect, any tropospheric hotspot observed will also be due to that enhanced greenhouse effect.

    What is true is that the tropospheric hotspot is not uniquely caused by the greenhouse effect. In fact, it is directly caused by an increase of specific humidity. That increased humidity increases the efficiency of energy transport to the tropopause, with a resulting reduction in the lapse rate (the rate at which temperature falls with increasing altitude). If the increase in specific humidity where to extend to the tropopause, the reduced lapse rate would mean the high troposphere would have warmed more than the surface. IMO, the jury is still out on whether specific humidity above 5 km altitude has increased, and also on whether the hot spot exists. As the decreased lapse rate with increased humidity is a negative feedback, its absence is hardly cause for comfort to deniers.

    Anyway, as the hotspot is a consequence of the increased humidity, any mechanism that warms the atmosphere will generate a hotspot. Indeed, solar heating which is strongest in tropical regions should generate a more distinct hotspot than does the greenhouse effect (which results in a greater relative warming near the poles).
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  34. mike williams @34, as an addendum to my comment, I would like to refer you to Chris Colose's comments @11 and 15 above.
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  35. scaddenp at 13:51 PM on 24 May, 2011
    Thanks for that, was that where Sherwood combined radiosonde data and added it to wind shear.?
    What other fields is wind shear used for measuring temperature.?

    Tom Curtis at 13:51 PM on 24 May, 2011
    In fact, it is directly caused by an increase of specific humidity.

    Thanks Tom. Wouldn`t that be directy linked to water vapour levels which appear to be dropping.
    http://www.cira.colostate.edu/cira/Climate/NVAP/satconf_2003_tv_poster.jpg

    Tom Curtis at 14:07 PM on 24 May, 2011
    mike williams @34, as an addendum to my comment, I would like to refer you to Chris Colose's comments @11 and 15 above.

    Thanks Tom..without being obtuse..most of it went over my head. :)

    Mike
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  36. Mike Williams @38: In the words of John Cook:

    "To claim that humidity is decreasing requires you ignore a multitude of independent reanalyses that all show increasing humidity. It requires you accept a flawed reanalysis that even its own authors express caution about. It fails to explain how we can have short-term positive feedback and long-term negative feedback. In short, to insist that humidity is decreasing is to neglect the full body of evidence."
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  37. Tom Curtis at 13:51 PM on 24 May, 2011
    mike williams @34, the sentence you quote is poorly phrased. As the current warming is predominantly due to the enhanced greenhouse effect, any tropospheric hotspot observed will also be due to that enhanced greenhouse effect.

    Thanks Tom..perhaps it should be.."the sentence you quote is wrong". : )

    I still dont understand if using "..indirect calculations of temperature based trends in the vertical differential in zonal wind acceleration from radiosonde measurements." is using a novel/ad hoc ? method for measuring temperature.
    When I asked what other areas of science use methods like this no one replied..so i will stay confused.
    Regarding John Cook`s statement "It fails to explain how we can have short-term positive feedback and long-term negative feedback",,
    Thanks for that, it rare to see the term "negative feedback" mentioned in the msm.
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  38. mike williams @40, my statement was correct. If you want to replace it with a falsehood for your own rhetorical purposes, it is only informative about your character.

    As to using wind speed as a measure of temperature, we currently use the following methods to measure temperture:

    a) the expansion of metals in glass tubes;

    b) the differential expansion of different metals;

    c) the change of plasticity in waxs and other compounds;

    d) the change in colour of waxes;

    e) the change in conductivity of metals;

    f) the colour of light from a source; and

    g) the change in the velocity of sound.

    Those methods are just the ones that come immediately to mind, and I am sure they are not exhaustive. Apparently you cannot recognise the use of wind shear data as a valid means of measuring temperature. As you have not advanced a single argument against the method beyond your disbelief, that shows us only that you are rejecting the analysis because you dislike the conclusions.
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  39. mike williams @40, my statement was correct. If you want to replace it with a falsehood for your own rhetorical purposes, it is only informative about your character.

    Hi Tom...

    You have to love postmodernism views on science and the meaning of words.. :)
    "The biggest misunderstanding about the tropospheric hot spot is the mistaken notion that it's caused by the greenhouse effect."
    Turns into
    "enhanced greenhouse effect"
    The IPCC use the term greenhouse effect Tom..
    http://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-1-3.html
    And there doesnt appear to be a difference between greenhouse effect and enhanced greenhouse effect in their interchanging usage in the IPCC papers either Tom..
    As for your strange and slightly juvenile "attack" on my character Tom..I gather you are exempt from the "ad hominem comments will be deleted" policy on the board..or do post modernists have a new interpretation of ad hominem as well as other words. ? : )

    As to using wind speed as a measure of temperature, we currently use the following methods to measure temperture:

    Thanks you very much for those examples Tom..much appreciated. !
    You learn something new every day.!

    "As you have not advanced a single argument against the method beyond your disbelief, that shows us only that you are rejecting the analysis because you dislike the conclusions."

    I had no belief either way..there are papers for it..there are papers against it..their are scientists for and against..
    I was just puzzled about the use of wind for temperature..sorry to express my puzzlement.. :)
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  40. "As to using wind speed as a measure of temperature, we currently use the following methods to measure temperture:"

    Thats correct Tom..but as you are more than aware..I was not asking you what other indirect ways do we measure temperature,I was asking you about using wind.
    My original question was
    What other fields is wind shear used for measuring temperature.?
    And you still didnt answer it..I will not bother you on this "sensitive" point anymore Tom..
    The answer to my question from the silence and evasion was probably...None.. :)
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  41. mike williams, you have been posing as a fair minded enquirer seeking illumination, but it is quite plain from the tenor of your questions and comments that you are in fact a denier trying various rhetorical gambits. For example, let's take your question about in what other fields is wind shear used as a measure of temperature. Clearly your purpose is to delegitimize the method on the basis that it is not used in any other field (if that is in fact the case). That represents an evasion on your part in that you are avoiding discussion of the physical basis of the method, a ground on which, no doubt you have no ground. So rather than tackling the science where it is strong, you use innuendo.

    Now, the correct answer to your question is, who cares? It does not matter that variation in the propagation speeds of sound waves is only used to measure the temperature beneath the surface of the sun (if that is in fact the case). What matters is whether temperature affects the propagation speeds of sound waves, and sufficient data can be gathered from this to determine internal temperatures. So, if it happens to be the case that only the sciences of meteorology and climatology use wind shear to measure temperature, so what? If oceanographers do not use wind shear to measure temperature, that is irrelevant to the use of the method. Likewise if metallurgists have also neglected this technique, or geologists. In fact, only sciences which measure wind (of which their are only three) could conceivably use this technique and two of those are so closely related that in this area they are not separate fields.

    The third science that could conceivably use this technique is astronomy. Whether astronomers ever have or not, well I hardly claim to be up on all the papers in that field, and I doubt many contributors to Skeptical Science are. But it is irrelevant whether they have or not.

    So, the proper interpretation to the silence that met your question (silence, note - not evasion because there was no response to your initial question at all by anybody), is that nobody cared. Your question was irrelevant.

    Of course, when you asked it a second time, it was clear what your rhetorical game was. So I provided an answer to the rhetorical point, your unsubtle suggestion that the method was ad hoc.

    And by the way, the method has been used before, though not in another field. In fact, the method was first used (that I know of) in climatology by that well known champion of AGW denialism, Roger Pielke Snr in 1998. As always, it is not the method deniers really have a problem with - it is the result.
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  42. mike williams @42, the reason I refer adversely to your character is quite simple, you have taken my words and misrepresented their content. I am careful with my wording because I am used to that tactic by both evolution deniers and AGW deniers (not to mention various 911 deniers, lunar landing deniers and other kooks I have had the misfortune of encountering on the internet) I stated that the sentence, "The biggest misunderstanding about the tropospheric hot spot is the mistaken notion that it's caused by the greenhouse effect" was poorly phrased because it did not properly express the intended meaning of its author. That intended meaning was "that the tropospheric hotspot is not uniquely caused by the greenhouse effect", as I stated in my 36. And of course, that is true. Therefore the original sentence was poorly phrased, not "wrong" because that would be incorrectly interpreted as an error of belief by the author, where no such error existed.

    Of course, you wanted that misinterpretation to flourish, hence your post 40.

    You show the same trolling pattern in your 42 when you bring in the term postmodernism as a rhetorical cudgel (which you incorrectly apply, and misdiagnose). What is more, instead of directing it at my actual response to you, you just choose technical terms at random (and evidently without understanding) to support your rhetorical attack. Plainly, for your, effect is far more important than relevance or cogency.
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  43. Mike, I think you're referring to "post-structuralist" views of language. Postmodernism is, as Fredric Jameson has it, "the cultural logic of late [global] capitalism." While the post-structuralism of the 60s and 70s may have been energized by the general postmodern conditions within the larger middle-class segments of the economy, the slipperiness of the link between signified and signifier has been noted for quite a while. Interestingly, post-modernity is expressed (well, one expression) in the rejection of metanarratives, and some view the scientific method as a metanarrative, one that places the mind exclusively within the material context, contradicting all other bases of "reality." Science is not, however, an individual pathway to reality. Science is socially developed. This makes it resistant to postmodern conditions. I strongly suspect, given Tom's record, that you'll find little postmodernity expressed in his comments. What the postmodern boils down to for Jameson, Baudrillard, even Hutcheon, et al., is that the generation of capital has become the central logos. People in the postmodern condition are willing to do anything--revise and mix up history, treat science as a cafeteria, treat anything and everything as commodity, etc.--in order to accomplish the neverending quest to generate more capital [Hi there, Michaels, Lindzen, Watts, et al.].
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