Friday, May 15, 2015


Sou | 6:05 PM Go to the first of 48 comments. Add a comment
There's a new paper in ERL by Steven C Sherwood and Nidhi Nishant, which reports an updated version of their radiosonde dataset. It is probably going to cause quite a ruckus in the deniosphere. From the paper (my formatting):
Temperature trends in the updated data show three noteworthy features.
  • Second, as shown in previous studies, tropospheric warming does not reach quite as high in the tropics and subtropics as predicted in typical models.
  • Third, cooling has slackened in the stratosphere such that linear trends since 1979 are about half as strong as reported earlier for shorter periods.
Wind trends over the period 1979–2012 confirm a strengthening, lifting and poleward shift of both subtropical westerly jets; the Northern one shows more displacement and the southern more intensification, but these details appear sensitive to the time period analysed. There is also a trend toward more easterly winds in the middle and upper troposphere of the deep tropics.

Radiosondes are instruments that are sent aloft in balloons, to take measurements in the atmosphere. (You might have seen Roy Spencer and John Christy combine measures from radiosondes with satellite tropospheric temperatures in their various unscientific attempts to befuddle the US government and readers of blogs.)

On his website, Steve Sherwood wrote about the change in this version from previous versions:
The updated dataset is prepared using the same methodology as the original version, and on the same stations, but with three modifications:
  • We now use straight wind vector data rather than wind shear. This permits us to produce a homogenised wind dataset which was not available previously.
  • Two small bugs were fixed but were not observed to have a significant impact on results.
  • Data are now available at all mandatory levels from 850 hPa to 30 hPa. However, we no longer provide "B" station data whose homogeneity cannot be obtained as confidently as for "A" stations.
  • Structural basis used to represent natural variability within the IUK iterative fitting algorithm now includes a cubic polynomial, which aids in capturing decadal variations more accurately.

I don't have time to write an article about the paper itself right now, but I thought I'd let you know about one aspect of it, which is upsetting the anti-science brigade at WUWT and elsewhere. (I imagine that Jo Nova and David Evans will be particularly upset.)

Tropospheric Hot Spot Observed

The latest update shows up a hot spot in the tropics, the tropospheric hot spot. This is a feature that physics predicts will happen any time there is warming, whether from greenhouse gases, El Nino’s, or solar forcing. The troposphere is highest above the tropics, and with warming, warm air rises up, creating what is known as a "hot spot" (an overly simplistic explanation - see the video and the references below for more).

The warming has been difficult to observe for several reasons. Satellites are coarse, with the temperature being measured in deep vertical bands usually several km deep. Radiosonde instruments are probably the best bet for taking measurements that would show this feature, but until now it's not been conclusive.

In this paper, the scientists report:
A maximum can be seen in the tropical upper troposphere in every latitude band from about 30S–20N, centred near 300 hPa. Because the trend reliability varies significantly among stations (with very scattered results in particular for stations in India), we follow S08 in taking the median of stations in latitude bands, although results are not highly sensitive to this choice.


About the Tropospheric Hot Spot

Thanks to MikeH in the comments, here is a short video about the hot spot:

Nine Denier 101 Techniques from the WUWT Disinformer's Manual

That's about all I have time for in regard to the paper itself. What's interesting is the lesson for Denier 101 that this paper has provided. At WUWT Anthony Watts has written an article full of denierisms (archived here).
  1. If it's science it's wrong: Anthony's headline has the usual "Claim:" right up front. This is mandatory for every scientific paper at WUWT, or almost every paper. It means that his readers are meant to reject science - any science but particularly climate science. That's expected at anti-science blogs all over, and WUWT is no exception.
  2. Halo-effect: In Anthony Watts's first sentence after the "Claim" headline, he links the lead author, Steve Sherwood, with another Professor from the University of New South Wales, and suggests that because on a recent trip to Antarctica, the vessel of that other Professor became stuck in ice, this means that the results of the updated radio-sonde data set reported by Steve Sherwood and Nidhi Nishant in ERL, are wrong. (Yes, really - go check!)
  3. Logic fail: In his next sentence, Anthony Watts claims that Roy Spencer, who reports satellite data, has been "looking for this for years in the satellite data". He provides no evidence. In any case, as indicated above, and in the ERL paper, it is much harder to interpret satellite data at the level needed. For one thing, the satellite data is easily smeared by the temperatures of the cold stratosphere (see the diagram above).
  4. The kitchen sink theory: Anthony knows the first three might not be sufficient for his readers, so he tosses in the kitchen sink, claiming that there aren't enough radiosondes. This is particularly odd, since he follows that up with a chart showing lots and lots of radiosondes all around the world. It's also odd because WUWT will often point to data from one single spot on the globe to argue that the entire world is cooling.
  5. After the kitchen sink: His next argument is because he's got nothing left. He's already used the kitchen sink. What he argues is that it can't be true because - and I quote "if they have really found it, where’s the picture or graph of it in the press release? " Ha ha ha. Seriously - go look and see.
  6. Stereo-typing: Anthony's next argument is that because Steve Sherwood is a climate scientist, his research must be wrong. (Anthony actually wrote: "Fifth, Steve Sherwood is a well known climate alarmist, and his confirmation bias seems quite strong to me.") In denier-speak, a "climate alarmist" is defined as anyone who accepts climate science. In denier-land, evidence can only be trusted when it has been cherry-picked for denier memes. Never, ever accept what the evidence shows.
  7. Made up nonsense - still not sure whether he will convince even his denier rabble of an audience, Anthony resorts to "making up stuff". That's always a good stand-by for deniers whether all else fails or not. He claimed that the scientists "threw out" data. (What he was probably referring to was the homogenisation process described in the paper, which is not the same thing.) This claim of Anthony's again is particularly odd, since Anthony Watts himself has been devoting much energy over several years to try to persuade scientists to "throw out" data of US weather stations as being "no good".
  8. Plea for help: Finally Anthony puts out a public plea to a known disinformer, writing: "Color me skeptical, I’m sure Dr. Roy Spencer will have something to say about it." He really, really wants Roy to come to his aid and deliver him some more denier arguments to prove that scientists (including Roy PhD) "don't know nuffin'".
  9. Can't find the data: Despite the authors pointing to the data, Anthony couldn't find it, and complained that the "The SI is pretty thin, containing a single figure with no explanation"

There you have it - denier 101 with nine examples, straight from the blog of Disinformer Class 1: Anthony Watts. Feel free to use them in your next critical thinking class :)

From the WUWT comments

Latitude is a hard-core denier, but he might not have been convinced that the science should be rejected, despite Anthony's best efforts. He noted that there were no climate models:
May 14, 2015 at 9:02 am
No climate models were used in the process …….they used statistics

Jack Savage wasn't persuaded by Anthony's best efforts either, and implied that he accepted the findings of the paper:
May 14, 2015 at 9:03 am
That will be the same hot spot that became unimportant all the time it did not appear as predicted. Expect it to become important again now it has been magicked into existence.

JimS weaves a convoluted conspiracy theory :)
May 14, 2015 at 9:15 am
Maybe this is all a ploy by “climate deniers” to encourage the IPCC to revive all its hotspot stuff it suppressed from its previous report. And then, when the IPCC does so revive all that hidden stuff, the climate deniers will come out and say, “Fooled ya!” Oh how devious of them there climate deniers, eh?

Salvatore Del Prete doesn't need Anthony Watts bending over backwards in denial to persuade him to reject science. It's his default position.
May 14, 2015 at 9:29 am
false as usual . can not be taken seriously. 

Rob Ricket regards scientific journals as shameless rags "requented by activist-hacks":
May 14, 2015 at 9:30 am (excerpt)
Click on the link below and you will doubtlessly conclude that Environmental Research Letters is a shameless rag frequented by activist-hacks. 

J. Philip Peterson is waiting to hear what Jo "Force X and the Notch" Nova has to say about all this:
May 14, 2015 at 3:52 pm
I’m waiting to see what Jo Nova has to say about this tropospheric hot spot found. She has always claimed that there isn’t any observed data presented to her about this hot spot. One of here major 4 points that the AGW people cannot provide the data to her, she maintains… 

Someone said recently that deniers wouldn't like this paper, and they were right. I wonder how many protest articles it will generate at WUWT?

References and Further Reading


Data for the above paper - from Steve Sherwood

Climate scientists find warming in higher atmosphere: Elusive tropospheric hot spot located - press release at ScienceDaily.com

Tropical tropospheric trends - older article at RealClimate.org

Tropical tropospheric trends again - older article at RealClimate.org

The Key to the Secrets of the Troposphere - older article at RealClimate.org


  1. The atmospheric physics behind the expected "tropical hotspot" and the associated denier myth is explained clearly here by Mark Richardson formerly of the University of Reading and now a postdoctoral scholar at NASA JPL/CalTech as part of the Denial101X MOOC series of videos.


    1. Thanks, Mike. I've added the video to the article. (I've fallen behind in my MOOC classes, I'm ashamed to admit. Work and other things are interfering.)

    2. Appallingly, stunningly poor commentary from Watts and the Wattites.

      The projection implicit in "Steve Sherwood is a well known climate alarmist, and his confirmation bias seems quite strong to me" is beyond parodying.

      In such an endless swamp of foolishness, that Watts got it wrong from the very start of his blog post because he misunderstood the UNSW news release to mean the "tropospheric hot spot" (a sloppy and misleading term not used in the paper) was located over the Southern Ocean rather than being a global phenomenon is barely worth a mention.

    3. Yes, Anthony conflated the "tropospheric hot spot" with the increased winds over the southern ocean from the look of things. More evidence that Anthony doesn't read the articles or press releases he copies and pastes.

      My bad for using the term "tropospheric hot spot" too. My paltry excuse could have been that it was used in the press release from UNSW - except that I wrote the article from the paper, before reading the press release, so that doesn't work :)


    4. Not sure that works either Sou. If the paper is not talking about a tropospheric hotspot where did the idea come from?

    5. 2015-16 will be a confronting year for deniers.

    6. Jammy the paper does talk about the hot spot. The paper found lots of things. One of them was the hot spot (see the article and the paper), another was increased winds over the southern ocean.

      Anthony conflated the two in his headline, as Magma said. He wrote:

      Claim: Climate scientists find elusive tropospheric hot spot over the Southern Ocean

      The hot spot isn't "over the southern ocean". It's the increased winds that are over the southern ocean.

    7. OK, that is clearer now. Thanks.

    8. Clearer.

      But why are you apologising - "My bad for using the term "tropospheric hot spot" too. "?

      You were not conflating with the winds, were you?

    9. Sorry, Jammy, for not being clearer. Magma pointed out that the term "tropospheric hot spot" is not very scientific and isn't used in the paper itself. I was just acknowledging that I used it in the article.

      Does that help?

      (It's not used in the realclimate.org articles either. I'm wondering if it's another case of "seepage" from denier terminology.)

    10. Oh, and for the second part of your question - no, I didn't confuse the hot spot over the tropics with the winds over the southern ocean.

    11. @ Sou, I checked Scopus and Web of Science for "tropospheric hotspot" and "tropospheric hot spot" with zero hits. It appears many university PR departments don't ask researchers to review their news releases prior to issue.

      Your guess seems correct. Christopher Monckton used the term in a 2007 blog post. http://scienceandpublicpolicy.org/monckton/greenhouse_warming_what_greenhouse_warming_.html

    12. Interesting, Magma. At least in this case it's only snuck into science blogs (or one blog) and not into climate science proper :)

    13. Thanks Sou. I had not appreciated that "hotspot" was not used in the scientific literature. Though I thought I had seen it used in "respectable" climate circles. Consulting my copy of "Atmosphere, Clouds, and Climate" (Randall) I see they do not use that description.

      Perhaps an example of seepage as you say.

    14. It is normally called the *tropical* hot spot, not tropospheric hot spot.

    15. It's also not really a hotspot. It's more like a band in the upper troposphere around the equator (centred just above the equator atm).


    17. "It's also not really a hotspot. It's more like a band" - when sliced for a 2D presentation, it looks like a "hotspot". Apparently, according to some, it is Monckton who originally misunderstood and thought it really *is* a hotspot rather than band around the equator, and the term has stuck in the denialsphere. Which is why the literature doesn't use the term but, I guess, why a press release might.

    18. Probably no seepage. First of all the term is not confusing. (Although it distracts a little from the harsh conditions up there, but people who know that that is a problem are not so easily confused.)

      Secondly, Peter Thorne, one of the main experts on this topic, claimed on twitter that the term "hot spot" is older.

      That type of 2D plot is extremely common. Thus that people call it a spot in not that surprising and I had not realised it was technically wrong until someone pointed that out this week.

  2. Replies
    1. Don't be so unnecessarily discourteous PG. I was genuinely puzzled over what the issue was.

      As it is all so crystal clear to you perhaps you could explain the link between the winds and the hotspot and why I should extend to global understanding as hinted at by this in the paper:

      "An attempt to reconstruct tropical warming profiles indirectly from changes in wind ..."

    2. Hi Jammy. Don't take too much notice of PG's jibe :)

      The paper doesn't suggest a link between the tropical hot spot and the winds over the southern ocean. The paper is about a study of radiosonde data. The data shows a number of things, including the two that you mentioned - and others.

      (Those two factors you mention have both been linked to global warming, incidentally. But they are not related to each other.)

      I've put a link to the paper above, plus the press release. Let me know if you have any more questions after reading them.

    3. Correction - the paper links the strengthened winds in the Southern Ocean to ozone depletion, not global warming. (I was going to write that initially then googled and found an article that linked the strengthening to global warming. I should have trusted my judgement/ memory.)

      The quote about "reconstructing tropical warming profiles etc" relates to the tropics, not to the wind over the Southern Ocean.

    4. No, the paper does not mention a hotspot as we have already established.

      It does mention linking winds to temperature profiles as I listed above. Also:

      "... to use shear was motivated by the local thermal-wind relationship between wind shear and horizontal temperature gradients."

      I guess I am just puzzled how you (and the knowledgeable PG of course) can separate out whether it is just Southern Ocean, connected to a hotspot etc etc.

      Perhaps I need to read the paper more assiduously.

    5. My understanding of the "Hotspot" is that it is not a signature of global warming. It should be found anyway. So, is this paper showing evidence of global warming or finding a hotspot? (Rhetorical question.)

    6. Jammy, as I wrote in the article, it is a sign of *any* warming, whether from El Nino, greenhouse warming or increased solar. So yes, it will appear with global warming.

    7. The other part of your question is in the paper. Yes, the paper does find overall warming of the troposphere and cooling of the stratosphere. Both are evidence of greenhouse warming.

  3. "So yes, it will appear with global warming."

    I am not sure what you mean by "it" but I guess you mean a hotspot.

    That is slightly misleading because it will also appear without global warming.

    1. Yes, "it" is the warmer upper troposphere over the tropics. How can what I wrote be misleading? I said it will appear with global warming. It could appear without greenhouse warming if the globe warmed from something else, like El Nino warming or warming from extra energy from the sun. But that doesn't contradict the fact that it will also appear with warming from greenhouse gases (commonly called global warming).

    2. Where you might be getting confused, Jammy, is that some deniers think that it will *only* be expected with greenhouse warming. As you rightly say, it can be with *any* warming - not just from greenhouse gases. Unlike, say, stratospheric cooling, which when combined with tropospheric warming *is* unique to greenhouse warming (AFAIK)

    3. More than that Sou. It will be there with global cooling.

    4. How? By what mechanism?

    5. I suspect he means that warming will strengthen the so-called "hot spot", while some degree of cooling would lead to a weakening of the so-called "hot spot" but that it would still be there.

      The point of all this is the warming "fingerprint" (regardless of the source of the warming) helps validate atmospheric physics. The simple denialist attack is to pretend a strengthening "hotspot" can only be caused by AGW. But Christy and other more sophisticated denialists argue that its absence shows our understanding of atmospheric physics in the face of warming is seriously wrong, and the models based on those physics so seriously wrong as to be useless (or so Christy, in particular, has argued).

      It therefore becomes an argument, in Christy's hands, that GCMs are so flawed that GCM-computed sensitivity to CO2 should be ignored.

    6. I think Jammy is implying that the lapse rate will be reduced at some height due to the exothermic nature of water condensation, whether there be warming of cooling. But what is generally meant by "hot spot" is more than that, it's the fact that upper troposphere in the tropics should experience more warming, due to the above mentioned change in lapse rate, and increased moist convection as explained by Micheal Mann in this post: https://www.facebook.com/MichaelMannScientist/posts/899451636777706
      Please correct me if I'm wrong.

    7. Yes, what they said. (dhogaza and Raoul, thanks).

      This video at 03:10 demonstrates a mechanism. Whether it is the whole story is another discussion.


    8. Jammy, I've added another article, including an explanation of why there wouldn't be a "hot spot" with global cooling. (It wouldn't be there if there was no warming either.)


    9. No with cooling there would be a cold spot. The mechanism amplifies any temperature change at the surface. You can also see it in the seasonal variations, for example.

      This was another reason why climatologists expected that the mechanism was right and that it is simply hard to detect the trend due to all the non-climatic changes in the radiosondes used to measure temperature.

    10. Thanks for doing all this work Sou. I will have a good read.

      I am sure I read somewhere there would not be a cold spot as that was not how it worked. I will have to track that down and see if I can resolve my understanding.

  4. https://www.facebook.com/MichaelMannScientist/posts/899451636777706

    1. Excellent - Thanks, John.

    2. Thanks for the link; fascinating stuff.

    3. Interesting. So, strictly speaking, less cooling isn't necessarily equivalent to greater warming ... :)

    4. I'll see if I can pull together an article about this over the next couple of days (I'm out all day today), and see if I can get a knowledgeable scientist to vet it - though that might be a challenge given it's the weekend. Still there's a lot of material around so I should be able to pull something together.

      (I think some of the comments here are off track.)

  5. What lies beyond the kitchen sink? The disposall, of course. :)

  6. What lies beyond the kitchen sink? The disposall, of course. :)

  7. Hey I think I've found another denier technique to add to the list. Not from Watts this time but from our very own illustrious leader: good old Tony.

    I spotted this story today (yeah I know, I'm a bit late):


    The part of interest is the first few paragraphs. Note that Abbott is not promising to address Australia's emissions. What he's saying is that he wants a strong agreement to limit "carbon leakage". There are two interpretations that spring to mind.

    First, he could have just made an honest mistake, and meant to say carbon emissions. Then again, it's Tony Abbott.

    Number Two interpretation: Since carbon leakage is apparently defined as industry moving offshore to avoid regulation of emissions, it would stand to reason that a strong agreement to prevent "carbon leakage" would have to be a strong agreement that Australia wouldn't do a damned thing about regulating its emissions, because if it did this would merely cause industry to move offshore.

    If you're a climate science denying twat who wants to avoid taking effective action at any cost, this would be the perfect tactic for cultivating a pretense of sanctity while continuing to emit like crazy. He can go to Paris and argue against regulation of Australia's emissions on the grounds of being a wonderful global citizen who wants to prevent carbon leakage. This should also play well at home, since it'll mean keeping industry in Australia, which will be good for jobs, etc.

    Since Australia's commitment proposal for Paris has to be aired in June, about now is a good time to start softening people up with a sleight of hand trick that substitutes "carbon leakage" for "carbon emissions".

    Of course, it's possible I'm being too cynical, but it is the Coalition I'm talking about, and this is exactly the sort of tactic I would expect from them anyway.



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