Saturday
Jun082013
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Bishop Hill
Bishop Hill A lucky escape for Roy Spencer
Jun 8, 2013 Climate: Surface Roy Spencer's recent post comparing climate model predictions to observations has been providing lots of entertainment in recent days - I really should have posted a link before. David Appell is unamused by Roy's thoughts though, and has taken him to task,declaring his blog post "unprofessional". He also has an interesting point to make about Roy's UAH temperature record:
But then there is this: the linear trend for the entirety of the two datasets on middle tropospheric temperatures in the tropics is
RSS MT 20S-20N: 0.090 ± 0.028 °C/decadeUAH MT 20S-20N: 0.030 ± 0.028 °C/decade
That's right -- their trends differ by a factor of three, with UAH by far the lowest -- a fact which is neatly hidden away in Spencer's graph by taking their average.
Just as well Roy didn't come up with a trend of zero eh?
Reader Comments (110)
@Turning Tide
Exact
Jun 8, 2013 at 9:53 PM | Unregistered Commenter Turning Tide
Why? Because it's a lovely little earner?...
The difference between 0.09 and 0.03 given the standard errors is not significant:
The t statistic for the difference is 0.06 divided by (0.028 times square root of two). That is 0.06 divided by 0.04 or 1.5 which is too small to be significant. It follows that the two estimates are not significantly different and that the best estimate for the temperature trend change is to take the simple mean.
Since the two estimates are not significantly different, the accusation against Spencer for hiding anything is off-target.
Focusing on relative differences violates standard statistical procedure, and is reckless.
The posting of David Allan serves rhetoric rather than enlightenment.
@Radical Rodent
"Are you on the side of reasoned argument, or spiteful name-calling?"
Put me down for the latter. Much easier, and much more fun.
The difference between UAH and RSS is 0.06 Deg C. One is 0.030 and the other 0.090 Deg C/Decade And the error margin for both are 0.028 C/Decade.
Technically UAH could be 0.06 C/Decade and so could also RSS also be.
http://s8.postimg.org/71v03r9w5/UAH_vs_RSS_TMT_Tropics.png
Shows that UAH started out warmer than RSS but quickly turned the same and shortly colder. Or is it the RSS that started colder but ends up with being warmer? Or both?
David Appell said:
"I didn't say models are "superior" to measurements. I said discrepencies should not automatically be assumed to be the fault of models, especially when the measurements are themselves heavily dependent on their own model, when they have a history of needing to be corrected, and when two different datasets trying to measure the same thing do not give the same result."
So UAH, RSS and balloon measurements of reality could all be totally wrong with a factor of 15 to 20?
"Nial: There is precedence for a discrepency between modeled and measured tropospheric temperatures being resolved in favor of the models:...[link to realhahaclimate"] --David Appell
Appellsauce.
> Nial: There is precedence for a discrepency between modeled and measured
> tropospheric temperatures being resolved in favor of the models:
From Spencer's article...
"Note that the observations (which coincidentally give virtually identical trends) come from two very different observational systems: 4 radiosonde datasets, and 2 satellite datasets (UAH and RSS)."
If this does need correction what do you estimate that to be?
When that's taken into account, how far away from reality will the 'model' results still be?
Will you stand back and look at the big picture?
For all of the commenters responding to Appell- you missed the point of Appell's participation here at Bishop Hill.
The point is not to argue or discuss things here at Bishop Hill.
The goal is provoking you into reaching a 'tipping point' where you visit his blog.
Jun 9, 2013 at 2:04 PM | chris y
His blog is not very popular - not that I have ever been there.
http://www.alexa.com/siteinfo/davidappell.blogspot.com#
Only 150 out of every billion internet users have visited his site.
Oh, very clever Chris. Well played sir! :)
Regards
Mailman
So UAH, RSS and balloon measurements of reality could all be totally wrong with a factor of 15 to 20?
That's not how the math works out, but in any case a 2006 report on which John Christy was a lead author says that there was too much uncertainty in the data to draw conclusions about the accuracy of model projections.
Now, 7 years later, the model projections are said to be double what they were then, and the measurement trend is half was it was then. And there is no mention of the uncertainties:
http://davidappell.blogspot.com/2013/06/hot-spot-or-not.html
Something in all that seems fishy.
Thanks for the sensible advice, Chris Y.
I'm already quite careful about not visiting one particular website-that-cannot-be-named (the one run by the dynamic-duo).
Guess it takes a special skill to create an ensemble, and Roy is not it.
David Appell still has not responded to three points:
1. The UAH and RSS are not "identical" measurements, but slightly different ways to measure global temps by satellite, so there is no reason that they should be precisely identical;
2. Both the UAH and RSS measurements, whether or not there is a statistically significant difference between them, are far closer to each other, and far below the "official" land based records (the keepers of which fail to acknowledge satellite or radiosonde measurements when writing or testifying about temperature trends); and
3. While Appell tries to criticize the two different satellite measurements, he fails to address the fact that radiosonde temp measurements closely resemble the satellite measurements, not the "official" measurements of the IPCC and Hadley and NASA. Radiosonde confirmation of satellite temps is telling -- hence if I were Appell, I would ignore them as well.
Bish, if this comment is too late to be seen my Mr. Appell and others, could you find a way to make it more observable, in hopes of compelling Mr. Appell to answer, or shaming him if he does not?
"John": Are you John Christy (and if so, why not say so?).... Will you be submitting this "Epic Fail" finding to peer review, or is a blog post sufficient these days?
Also, aren't RSS and UAH measuring the same thing, albeit by slightly different methods?
If so, why does RSS show a total of 0.31 C of warming for the MT tropics, and UAH 0.10 C of warming? That's a significant difference.
Finally, in 2006, John Christy wrote, about the tropical troposphere, that "large observational uncertainties...make it difficult to determine whether or not models still have significant errors."
http://davidappell.blogspot.com/2013/06/hot-spot-or-not.html
How much has that changed by 2013, and what *are* the errors in Roy Spencer's graph? Measurers are supposed to put error bars on their results.
To David Appell:
No, I'm not John Christy. Call it my Nom de Plume....
And you still haven't answered the questions.
"John": Reveal your identity and I'll answer your questions.
P.S: There are claims that UAH is, yet again, biased low:
Po-Chedley, Stephen, Qiang Fu, 2013: Reply to “Comments on ‘A Bias in the Midtropospheric Channel Warm Target Factor on the NOAA-9 Microwave Sounding Unit’”. J. Atmos. Oceanic Technol., 30, 1014–1020.
http://journals.ametsoc.org/doi/abs/10.1175/JTECH-D-12-00131.1
David, I'm sorry, but I do wish to keep my real identity to myself.
I'm sorry that is an impediment to your answering questions about what you write.
It's not about understanding, it's about honesty. If, in a scientific debate, you can't be honest about your name, who knows what else you won't be honest about.
David, I'm sorry, but there are reasons for wanting to keep one's name private, both personal and professional.
I don't understand, however, why that precludes answering questions highly relevant to issues you have raised.
Because it's professional to use your real name (especially if, as it appears, you're deeply involved in the issue, and perhaps even from UAH), and it's courteous.
To David Appell:
I'm not professionally involved in climate science, although I do research. Obviously, I'm not employed by UAH.
Again, it seems to me that you are hiding from answering questions relevant to what you have written. I can't see why it is so hard to address the three questions I asked above. You brought up the subject of whether the difference in tiny numbers (RSS vs. UAH) was a huge matter. I'm simply asking you questions relevant to the subject matter.
You seem to be digging very hard for reasons not to reply.
Turning Tide
They might have noticed the receding glaciers, the melting ice sheets, the disappearing Arctic ice, the thawing permafrost, the rising sea levels, the changing rainfall patterns, the changing biome boundaries, the droughts and the flooding.
"Both the UAH and RSS measurements, whether or not there is a statistically significant difference between them, are far closer to each other, and far below the "official" land based records"
John
The satellite temperatures are not far below the land based records. They have only been running since 1979 and use a higher baseline to calculate the anomaly readings.
Professionals who do science and then opine about science do so under their real names -- or they're not professionals.
Otherwise, what are they hiding, and why?
@Entropic Man
"They might have noticed the receding glaciers, the melting ice sheets, the disappearing Arctic ice, the thawing permafrost, the rising sea levels, the changing rainfall patterns, the changing biome boundaries, the droughts and the flooding."
All of which are within the bounds of known natural variability (some well within the bounds, e.g. sea level).
@David Appell "Professionals who do science and then opine about science do so under their real names -- or they're not professionals.
Otherwise, what are they hiding, and why?"
Another epic fail. What difference would it make to you if you knew people's real names? Whether people are hiding anything or not, and their reasons for hiding anything, if indeed they are, in no way impinges on your answers to question put to you.
If you only want to communicate with professionals using their real names, why do you blog rather than writing in the peer-reviewed literature? And why do you permit pseudonyms on your own blog?
David Appell
If I supported the consensus opinions expressed by the denizens of this site, I would be too embarassed to give my real name too. "John"s colleagues might find out!
Turning Tide: A professional commenting anonymously immediately raises the question of why. What are they hiding? In whose name are they acting?
Are they a sockpuppet? Based on the log of visitors to my blog, I have my suspicions.
Anonymous commenters simply aren't serious. Including you.
Turning Tide wrote:
All of which are within the bounds of known natural variability (some well within the bounds, e.g. sea level).
Completely false -- nor can you defend your own statement.
All of which are within the bounds of known natural variability (some well within the bounds, e.g. sea level).
Jun 10, 2013 at 10:30 PM | Turning Tide
I keep hearing about this natural variability from sceptics. Where's the evidence?
The historically and currently observed solar vaiations are capable of generating changes around 0.25C. Oceanic cycles such as AMO produce 0.3C. The glacial/interglacial cycle generates a 5C change, but over millennia. Volcanic effects last a couple of years.
Temperature changes do not occur spontaneously. They occur because something drives changes in energy flow and energy budgets.
If natural variability were producing the temperature increase observed since 1880 it would be easy to show which specific mechanisms were involved and their energy contribution. Do not tell us, show us!
You should be able to produce specific data linking obseved temperature changes and measured energy changes due to natural mechanisms. If not, stop hand waving.
If natural variability were producing the temperature increase observed since 1880 it would be easy to show which specific mechanisms were involved and their energy contribution. Do not tell us, show us!
Yes, do. So-called "skeptics" demand to be taken seriously, in every respect except by producing better science.
@David Appell
"Turning Tide: A professional commenting anonymously immediately raises the question of why. What are they hiding? In whose name are they acting?
Are they a sockpuppet? Based on the log of visitors to my blog, I have my suspicions.
Anonymous commenters simply aren't serious. Including you."
So what? Does your answer to a question depend upon who's asking?
@Entropic Man "If natural variability were producing the temperature increase observed since 1880 it would be easy to show which specific mechanisms were involved and their energy contribution. Do not tell us, show us!"
If neither the models nor the observations can be relied upon, how do you know by how much the temperature has increased since 1880? If even that basic fact cannot be established, if seems perverse to speculate upon the nature of the mechanisms involved.
If neither the models nor the observations can be relied upon, how do you know by how much the temperature has increased since 1880?
Because ice is melting. You can't fake that.
"Because ice is melting. You can't fake that."
Ice has melted before, when the effects of anthropogenic emissions couldn't have been responsible.
Ice has melted before, when the effects of anthropogenic emissions couldn't have been responsible.
Dumb responses like this don't help your cause any.
@David Appell
Perhaps you could at least endeavour to be civil?
There is evidence for an ice-free Arctic Ocean in the recent past; for example, see here (there is at least one peer-reviewed paper associated with this research too).
Turning Tide: *Why* did ice melt in the past?
Turning Tide
The reduced Arctic ice extent you reference occured at the peak of the current interglacial, when the forcing due to favourable Milankovich effects was at its peak and temperatures were similar to today's. We are well into the subsequent decline from that peak. Natural variation is generating negative forcing effects which should be pushing both temperature and CO2 lower. There are no natural mechanisms to explain the current long term reversal of that downward trend.
You cannot just refer to a past climatic event as proof that the current warming is natural. It is necessary to put the past event in proper context.
Notice how fast "John" disappeared when I insisted on his real name.
I am still not convinced he wasn't John Christy.
David - I read it as he got bored with you.
I read it that he was a coward.
He answered your question with an explanation which you chose not to accept. That allowed you to avoid answering his questions. I read that as cowardice too, but not on John's part.
What questions? If you read coward-John's first post, there are no question marks in it at all.....
John's post starts with "David Appell still has not responded to three points:" and concludes with a request that the Bish make the post observable by you in order that you should respond. Between the opening and the conclusion he lists three points. Question marks are not required.
I am bored with you now. Good night - if you have a response, particularly on the radiosonde point, I'll read it tomorrow.
There are no questions in "John's" comment, and I am bored with dealing with his cowardice.
If he has questions, he knows how to write to me: david.appell@gmail.com