2005-11-07

Sh*t* frm Lindzen

Lindzen is a bit of a contrarian, but I had thought he mainly kept his skepticism within the bounds of reason and deserved his "k". I now find I'm wrong: I recently found Lindzens testimony for the House of Lords. Its so bad its funny. Consider:

Lord Kingsdown: Can I just go on to ask you how far your view of the role of water vapour is shared by other scientists?

Professor Lindzen: That is shared universally.


What utter bilge! Lindzen is out on a limb on his Iris Hypothesis, which has by now been discarded by just about everyone. He's welcome to like his own research himself, of course, but pretending that anyone else does is dishonest. The rest of it is cr*p too.

30 Comments:

Blogger Dano said...

That IR iris was smacked down almost immediately and never really got back up. If'n that's not a lie, the truth is stretched so thin as to be effectively transparent.

D

12:02 am  
Blogger James Annan said...

He's even still claiming a climate sensitivity of about half a degree (p23)!

1:31 am  
Anonymous Steve Bloom said...

After I posted the abstract of that recent Science water vapor paper on Ask Stoat, I took a look around and discovered that there have been a couple of papers which directly refuted the Iris idea and to which Lindzen has made no reply. The upper tropical troposphere is wet, wet, wet and there is no possible distortion of the Iris that can adapt to that fact. Lindzen hasn't even put any kind of defense to this stuff on his MIT web site. To all appearances, it's been something like five years since he actively defended the Iris or even published much of anything on any subject. Just so we're all clear on this (since I wasn't), Lindzen was a serious skeptic way before he came up with it. He had an attitude in search of a rationale, and from the Lords crap it doesn't appear that much has changed.

1:36 am  
Blogger Belette said...

Dano - yes, and I rather suspect that Lindzen doesn't even believe it any more.

James - ah, indeed, do you think he might bet on it :-)?

Steve - I haven't forgotten that paper, just waiting for time to read it properly. As to L's attitude... I really did think he was more reasonable and careful, despite his contrarian tendencies. I think I may have to re-evaluate my opinion of him (gosh what a threat!)

9:53 am  
Anonymous Willis Eschenbach said...

Y'all might be better advised to actually read what Lindzen said before jumping on the bandwagon. He said:

Q144 Lord Kingsdown: "Can I just go on to ask you how far your view of the role of water
vapour is shared by other scientists?"


Professor Lindzen: "That is shared universally. All of them agree, no model gets a lot of
response to CO2, much more than you would expect on basic physics, unless water vapour
and cloud kick in to make the system much more sensitive than it would be in the basic
physics. That is true and accepted."

Now I ask: is that true and accepted, that no model gets a lot of response to CO2 without the hypothetical water feedback? That's what he said was "shared universally", nothing about the Iris, that was his statement.

Is it true? Yes, as far as I know. And since it is ... why are you slagging Lindzen?

2:11 pm  
Blogger Belette said...

Willis - you need to look at the full context - his comments *before* the question. I agree: Lindzens reply is structured so as to have a defensible fall back position, when its pointed out that the obvious interpretation of his comments is indefensible: ie, he talks about the now-junked Iris stuff as if it was still current, pretends that follow-ups have been positive instead of critical; then gets asked about how his fellow scientists view his views and says "oh they all agree". The HoL folks will have taken his words to mean *agree with what has just been said*, and thats what L meant them to think. The comment *after* (WV feedback) is anodyne; where he misrepresents the state of the science is that he is about the only scientist to think it doesn't apply in real life.

2:34 pm  
Anonymous Willis Eschenbach said...

Belette, thanks for the post. I read very carefully what Lindzen said. He was extremely clear about exactly what he was claiming was shared by other scientists.

Yes, he had been talking about the Iris effect before. But he was not asked about the Iris effect. He was asked if his views were shared, and he listed the views he thought were shared.

Your claim that he was busy manufacturing a "defensible fallback position" might be believable if he were writing the answer and could spend a half hour figuring out exactly how to word a tricky response. However, it was an off-the-cuff answer to oral questioning, so that interpretation is both laboured and highly unlikely -- none of us think that fast on our feet, to simultaneously answer the question and craft a complex fallback position in real time.

He said what he said. If you start reading "complex fallback positions" into what he said, you can interpret it any way you choose.

Me, I'd rather stick with the claim he made. He said exactly what he thought was accepted. I accept it. All climate modelers I know of accept it.

Do you?

2:46 pm  
Blogger Belette said...

Willis - you're welcome to your opinion, of course. Calling this off the cuff won't work though - this junk is the core of Lindzens position: it is carefully pre-planned stuff.

7:51 pm  
Blogger Peter Hearnden said...

I see on page 23 of the report Prof Lindzen say's this "It is true that the models are predicting four degrees, but
the same models predict three degrees for today, and we do not see that." It's news to me! What models predict three degrees warming for today?

8:36 pm  
Blogger Belette said...

Peter - I share your confusion. What seems to have happened is that Lindzen has noticed that current GCMs do accurately predict temperature change over the past century, but since this won't fit into his septical viewpoint (see, he's lost his k now) he has had to throw out those data points. What he has replaced it with seems to be his own view that *if* you ignore important forcings (sulphate aerosols) and *if* you shuffle a whole pile of uncertainties onto the side you want and *if* you confuse equilibrium and transient climate sensitivity *then* you can just about persuade yourself (even if no-one else) that GCMs predict 3 oC T change today. Since they don't, it s patent nonsense, and its rather hard to understand why the HoL people, ignorant of the science as they obviously are, didn't notice this.

Sorry about the rant. I find it rather irritating that this stuff gets put around. It does illustrate how hopelessly out of their depth the HoL people were though.

8:52 pm  
Anonymous Steve Bloom said...

I would agree with William that it's very obvious that Lindzen was speaking from prepared notes, and that the conflation of the WV/Iris business was thus intentional.

(Willis, people don't just show up and blather randomly at hearings like this. The committee staff if not the chair would have known exactly what Lindzen was going to say. Given Lindzen's written material, my conclusion is that the staff/chair wanted to use Lindzen's oral testimony to impress on committee members that there's a real qualified climate scientist who thinks the consensus is wrong. Willie Soon, Pat Michaels, Fred Singer etc. wouldn't have had quite the same impact, so Lindzen played an important role that we can be fairly concerned will be repeated in other venues.)

The Lords report itself does not appear to have conflated these issues, but did mention both the Iris effect and the 3 degree business rather prominently (although pointing out that they are minority views) as part of their case for uncertainty in the science. The hockey stick of course also got a prominent mention in this regard, but I was confused by their reference (repeated a couple of times) to a "Dr." McIntyre. Does anyone know of such a person? :)

10:58 pm  
Anonymous Thomas Palm said...

Willis, even the Linzen fallback position is untenable. He says "unless water vapour and cloud kick in to make the system much more sensitive than it would be in the basic physics."

The water vapor increase is part of the basic physics. Only by some very contrieved mechanisms have Lindzen been able to claim that water vapor will not increase as the world warms. Everyone else from Arrhenius onwards have concluded differently.

10:08 am  
Blogger crandles said...

Is the 'three quarters' accurate?

380ppm/280ppm=1.357
1.357^2.27=2

So I would have thought that we would have had (1/2.27) =44% of the radiative effect of doubling, not 75%.

(You have already made the point that we haven't seen the full temperature and other effects of the radiative effect.)

Have I screwed up my maths?

Trying to use my figures:
If we have seen .6C temperature rise and there is a further .5C if we kept CO2 at current levels, and had there been no CO2 increase there would have been a slight cooling (taken as negligable because I don't remember seeing a figure quoted),

then sensitivity = (0.6+0.5--0)/.44=2.5C

I'd like to see error bars on those numbers. Also, if the sensitivity is more likely to be 6 than 0.5 does that mean there is similar distribution for estimates of the amount of further warming we would get if CO2 held steady at 380ppm?

3:01 pm  
Anonymous Willis Eschenbach said...

Before claiming so passionately that Lindzen is wrong, you might consider the following study:

On the decadal increase in the tropical mean outgoing longwave radiation for the period 1984–2000

D. Hatzidimitriou, I. Vardavas, K. G. Pavlakis, N. Hatzianastassiou, C. Matsoukas, and E. Drakakis, Atmos. Chem. Phys., 4, 1419–1425, 2004
www.atmos-chem-phys.org/acp/4/1419/SRef-ID: 1680-7324/acp/2004-4-1419


Hatzidimitriou and his team have produced two other studies of the same period, one for global downwelling long wave, and one for global downwelling shortwave. His team's results are widely considered the best analyses to date of those variables.

As the title states, the study found that OLR in the tropics increased over the period. Here is the abstract:

Abstract. In the present paper, we have calculated the outgoing longwave radiation at the top of the atmosphere (OLR at TOA) using a deterministic radiation transfer model, cloud data from ISCCP-D, and atmospheric temperature and humidity data from NCEP/NCAR reanalysis, for the seventeen-year period 1984–2000. We constructed anomaly time-series of the OLR at TOA, as well as of all of the key input climatological data, averaged in the tropical region between 20 N and 20 S. We compared the anomaly time series of the model calculated OLR at TOA with that obtained from the ERBE S-10N (WFOV NF edition 2) non-scanner measurements.

The model results display very similar seasonal and inter-annual variability as the ERBS data, and indicate a decadal increase of OLR at TOA of 1.9±0.2Wm−2/decade, which is lower than that displayed by the ERBS time-series (3.5±0.3Wm−2).

Analysis of the inter-annual and long-term variability of the various parameters determining the OLR at TOA, showed that the most important contribution to the observed trend comes from a decrease in high-level cloud cover over the period 1984–2000, followed by an apparent drying of the upper troposphere and a decrease in low-level cloudiness.

Opposite but small trends are introduced by a decrease in low-level cloud top pressure, an apparent cooling of the lower stratosphere (at the 50 mbar level) and a small decadal increase in mid-level cloud cover.


Now there's a couple of things I'd like to highlight.

Earlier, someone on this blog confidently stated that "The upper tropical troposphere is wet, wet, wet and there is no possible distortion of the Iris that can adapt to that fact." Well ... no. As the abstract above shows, not only is it wet, wet, wet, it is also drying, drying, drying ...

Now Lindzen said that what was happening was that the iris was opening, which increases the OLR. He also stated that the mechanism was the decrease in the cirrus (high) cloud cover.

This study says that OLR is increasing, and that the reason is the decrease in the high-level (cirrus) clouds.

Seems to me that Lindzen's position has been strongly upheld.

But in any case, why the vitriol? Lindzen is a scientist who believes in his hypothesis. Perhaps he is wrong, perhaps not. The Hatzdimitriou study says Lindzen is absolutely right, so he is not just operating in a vacuum with his hypothesis.

Meanwhile, some of you guys here seem just to want to make nasty about him. Even the title of the thread. What's up with this mean spiritedness? Did he come and piss on your flowers or something? I don't understand why y'all are so upset.

w.

6:33 am  
Blogger Belette said...

Willis - the reason people are p*ss*d off with Lindzen is because he uses his reputation as a scientist to talk cr*p to non-scientists (like the HoL): he grossly misrepresents the state of the science. I'm surprised you can't see this. Quite why he does this is unclear: most likely because he has pained himself into a corner.

10:16 am  
Anonymous Willis Eschenbach said...

Well, that's wierd. I posted last night, and it didn't appear. Then I checked this morning, still no post, so I reposted, only to find both, along with a reply from Belette ... go figure.

Belette, thanks for your comment. You say:

Willis - the reason people are p*ss*d off with Lindzen is because he uses his reputation as a scientist to talk cr*p to non-scientists (like the HoL): he grossly misrepresents the state of the science. I'm surprised you can't see this. Quite why he does this is unclear: most likely because he has pained himself into a corner.

As I have just shown, at least three parts of what you thought was "crap" actually turn out to be true. 1) The OLR is increasing. 2) It is from the "Iris Effect" of decreasing cirrus clouds". 3) The upper troposphere is drying out.

Now that we know that those ideas of Lindzens are not "crap", now that they have been clearly shown to be true, does that mean the contrary ideas which you have been espousing are "crap"?

And now that we know that Lindzens ideas are not "crap", could we please dial back the rhetoric a bit? Lindzen believes what he believes. He has a responsibility as a scientist to state and defend those beliefs.

For you to abuse him for doing just that is unjustified and unwarranted. For you to call his ideas "crap" can only hurt you, as in this case when his ideas are upheld and you are left with the "crap" on your faces ... for me, it's preferable to assume that the other man is honestly upholding an idea he believes in. That way, when his idea is proven to be right, I don't end up looking like an irate third-grade student ...

Finally, a question. You say Lindzen uses his position "to talk cr*p to non-scientists (like the HoL): he grossly misrepresents the state of the science."

Now y'all have been claiming that

:: increasing temperature will inevitably increase water vapour (gross misrepresentation)

:: the troposphere is wet, wet, wet, and there's nothing the Iris can do about it (gross misrepresentation)

:: Lindzens Iris hypothesis, that OLR is increasing because cirrus clouds are decreasing, is ridiculous and wrong (gross misrepresentation)

This makes me a little suspicious when you claim that Lindzen is guily of gross misrepresentation, so my final question is:

Now that we know that Lindzen is right and y'all were wrong about cirrus clouds, about the OLR, and about the decrease in water vapour, what further "gross misrepresentations" is Lindzen guilty of?

w.

8:32 pm  
Blogger Belette said...

Willis - you can believe Lindzens stuff if you like. I've deleted your duplicate. But quoting one paper using NNR reanalyses is not convincing, I wouldn't trust them for upper trop moisture (their ppn around Antarctica is poor).

So how about some observations instead?

The Radiative Signature of Upper Tropospheric Moistening

Brian J. Soden, Darren L. Jackson, V. Ramaswamy, M. D. Schwarzkopf, Xianglei Huang

Climate models predict that the concentration of water vapor in the upper troposphere could double by the end of the century as a result of increases in greenhouse gases. Such moistening plays a key role in amplifying the rate at
which the climate warms in response to anthropogenic activities but has been difficult to detect because of deficiencies in conventional observing systems. We use satellite measurements to highlight a distinct radiative signature of upper tropospheric moistening over the period 1982 to 2004. The observed moistening is accurately captured by climate model simulations and lends further credence to model projections of future global warming.

Helpfully provided by Steve Bloom.

So... we (and now you too) know that Lindzen is wrong.

9:40 pm  
Anonymous Willis Eschenbach said...

Belette, thank you for removing the duplicate, and for your post. You say:

Willis - you can believe Lindzens stuff if you like. I've deleted your duplicate. But quoting one paper using NNR reanalyses is not convincing, I wouldn't trust them for upper trop moisture (their ppn around Antarctica is poor).

Not quite sure how Antarctica came into the picture, as far as I knew we were only discussing the tropics. Is that correct?

So how about some observations instead?

The Radiative Signature of Upper Tropospheric Moistening

Brian J. Soden, Darren L. Jackson, V. Ramaswamy, M. D. Schwarzkopf, Xianglei Huang

Climate models predict that the concentration of water vapor in the upper troposphere could double by the end of the century as a result of increases in greenhouse gases. Such moistening plays a key role in amplifying the rate at
which the climate warms in response to anthropogenic activities but has been difficult to detect because of deficiencies in conventional observing systems. We use satellite measurements to highlight a distinct radiative signature of upper tropospheric moistening over the period 1982 to 2004. The observed moistening is accurately captured by climate model simulations and lends further credence to model projections of future global warming.

Helpfully provided by Steve Bloom.

So... we (and now you too) know that Lindzen is wrong.


My thanks to you for this citation, and to Steve as well. OK, this is actually an excellent example. You have presented a study saying that the water vapor in the upper troposphere is rising. It's a good paper, because it highlights many of the issues of the current discussion of climate.

Upon first examination, I have four problems with the study. The first one was this. The most curious thing to me about the study was this quote in the middle:

"Under clear skies, T12 is primarily sensitive to changes in relative humidity averaged over a deep layer of the upper troposphere (roughly 200 to 500 hPa) (21)."

I read that about four times before I thought "relative humidity? Why relative humidity? Isn't the absolute number of molecules, that is to say parts per million, the variable?" So I went to look at the authority for their claim that T12 is a proxy for relative humidity, that is, their reference (21).

Well, (21) turns out to be their own online supporting material, located at:

http://www.sciencemag.org/cgi/data/1115602/DC1/1

It's a single PDF, 9 pages long, and there is not a word in there to justify using T12 as a measurement of relative humidity. In fact, the term "relative humidity" doesn't appear in the document at all. They say, instead: "The HIRS channel 12 is sensitive to water vapor over a broad layer of the upper troposphere which shifts from ~200-500 mb in the tropics to ~350-700 mb in the mid-latitudes." Not relative humidity, but water vapor.

Now, I don't like this. Their whole argument rests on the claim that T12 measures relative humidity. But their citation for the claim is to themselves, and when examined, the cited document doesn't say a word about the question.

Let me say that, as a frequent victim, I am not unfamiliar with the idea of the stupid error, like where you mix up your citations, and this may be just that. I've made many stupid errors in the past.

But the confusion gets deeper on further investigation. In fact, T12 is not proportional to relative humidity. It is best approximated by

T12 ~ (H/(T6-T4))^(1/1.13)

SOURCE:http://www.aero.jussieu.fr/~sparc/WAVASFINAL_000206/WWW_wavas/Chapitre1/1_4_SatelliteSensors.html

where H is relative humidity, and T4 and T6 are the HIRS brightness channels 4 and 6 in the lower and upper troposphere (a measure of the tropospheric lapse rate). While this dependence on the lapse rate is smaller in clear-sky conditions, it is by no means removed. The IPCC TAR says "Convection also in large measure determines the vertical temperature lapse rate of the atmosphere, and particularly so in the tropics." Thus, without information on the lapse rate, the T12 temperature tells us nothing.



The second problem I have with the study relates to the computer models. The study is based around the HIRS satellite channel 12 brightness temperature (T12). The study states that there has been very little overall change in T12 over time, and that this lack of any trend in T12 is verified by several studies. It then gives a table (Table 1) containing the following information:

Change in T12 (K/decade)

0.00 ± 0.04 (HIRS Channel 12)

This agrees with the text, showing absolutely no change in T12.

Then they say the 4 GCM results are:

0.06 ± 0.04
0.07 ± 0.04
0.08 ± 0.04
0.06 ± 0.04

All four of these show a significant increase in the T12 temperature, with two of them being significant at the 99.7% level and two at 95%.

Now stop and consider this a moment.

1) The T12 trend is a central part of the study.

2) The data shows no change in T12.

3) The model results all show a significant increase in T12.

For me, the story ends there. If the models can't even get the trend of the T12 data correct, how can they possibly be used to support or oppose any conclusions on other aspects of the T12 question? Perhaps someone might shed some light on this conundrum, but until then, I consider any results from these GCMs as being worthless for resolving the question at hand.



The third problem is best shown by the following study:

A cautionary note on the use of Gaussian statistics
in satellite based UTH climatologies
V. O. John, S. A. Buehler, and N. Courcoux
http://www.sat.uni-bremen.de/members/viju/publication/uth-diff-mcarlo/GRSL-00110-2005.pdf

Abstract— This article presents a cautionary note on the as-
sumption of Gaussian behavior for upper tropospheric humidity
(UTH) derived from satellite data in climatological studies,
which can introduce a wet bias in the climatology. An example
study using ECMWF reanalysis data shows that this wet bias
can reach up to 6 %RH, which is significant for climatological
applications. A simple Monte Carlo approach demonstrates that
these differences and their link to the variability of brightness
temperatures are due to a log-normal distribution of the UTH.
This problem can be solved by using robust estimators such as
the median instead of the arithmetic mean.


This study clearly shows that the UTH distribution is not Gaussian, and that using Gaussian statistics can "introduce a wet bias in the climatology". If the authors of the Soden et. al. study are aware of this problem, they have chosen to ignore it.



The fourth problem is that the study only covers clear sky conditions. While this may be adequate for temperate zones, the average moisture content of the tropical air is ruled by what is happening in the clouds, in particular thunderstorms. These are the main engines of the tropical circulation, hoisting huge amounts of water into the sky and then raining it back down again. The area in between these thunderstorm columns of rising air consists of clear-sky, downward moving, generally dry air. (It is not widely realized that much of the tropical upper tropospheric air is at about 20% RH ...) The moisture has been mostly removed from this air, and it is descending to pick up more moisture. Any analysis of this descending, dry air must perforce give a very distorted view of what is happening on average in the tropics, because the real action is taking place in the thunderstorm towers.



OK, so what can we conclude from this study? My first conclusion is that Soden's case must be very weak, as he has used both erroneous computer models and inappropriate Gaussian statistics to try to support it. My second conclusion is that, because of the bad models and and bad statistics, it should not have made it past the referees.

However, it did. So now we have two studies, showing the tropical upper troposphere as either moistening or drying depending on which study one believes. This, to me, could stand as a central theme of the climate debate -- the science, as we see from these two studies, is not yet settled.

In large part, this is because the signal we are looking for is unbelievably tiny. Let us assume that the 0.6°C of theoretical warming from a CO2 doubling is somehow kicked up by a hypothetical feedback to say 1.5 - 2 degrees. There is no evidence to say that this will happen, and there are theoretical arguments on both sides to say either it will or won't. But let's say that it does.

The IPCC projections put the doubling (from the present value) out about 100-150 years, depending on the "scenario". This means that the maximum signal we are looking for is about 2°/100 years = 0.02° per year. Since our weather records generally are only to the nearest degree, this is a long ways below instrumental accuracy. In addition, the noise in the system is huge. The day-night temperature swing at any given location is typically about a thousand times larger than the signal we are trying to find.

Which is a major reason why the debate rages on, because the signal is so small. Consider Kyoto in this regard. Both supporters and opponents of Kyoto figure that if the signatories are able to make the specified reductions, it will make a maximum of about 0.06° difference in the temperature by 2050. This is far, far too small a change to measure, which means that we will never know if Kyoto has had any effect at all.



Now, I'm not putting all of this up on the silver screen to argue one side over the other. My point is simply that Lindzen has studies that support his hypothesis, as do you. Given the generally poor quality of many of the papers presented by both sides in the discussion, and given that there is no scientific certainty or agreement on the basic heads of discussion, and given that we do not even know all of the forcings involved in climate, much less their size and sign, to call your scientific opponent's results "cr*p" while insisting that your own sh*t don't st*nk is pompous and arrogant.

But much more to the point, you are only hurting yourselves with these kind of claims. Disagree with the science, by all means. But when you start these ad hominem attacks, real scientists just start laughing ...

So unless you want the scientific world to continue to laugh behind closed doors at your childishness, unless you really enjoy having scientists roll their eyes when your name is mentioned, I'd suggest a bit of humility and some respect for those who don't happen to believe the gospel truth as revealed by you ... you might think it's the gospel, but there are many people out here who are unconvinced. Your nastiness will not ever convince them, in fact it has the other effect -- it makes you look desperate. Humorously desperate, but desperate nonetheless ... that the image you want to project?

w.

11:23 pm  
Blogger Peter Hearnden said...

Well, if mere words and exhorations could convince...

Wills, infact you must be being amazingly disingenuous. You must know, surely, how temperature averages are produced? You must know, surely, that a quick 2C is an *enormous* amount in climate terms? The way you talk, I think you'd find it hard to detect an ice age! Indeed you could have said (I haven't time to figure out the exact multiplier) "The day-night temperature swing at any given location is typically about about a hundred times larger than the signal we are trying to find if were looking for an ice age"! So what?

Still, you did manage to get your ad homs in :)

10:10 am  
Anonymous Willis Eschenbach said...

Peter, thanks for your post. You say:

Wills, infact you must be being amazingly disingenuous. You must know, surely, how temperature averages are produced? You must know, surely, that a quick 2C is an *enormous* amount in climate terms? The way you talk, I think you'd find it hard to detect an ice age! Indeed you could have said (I haven't time to figure out the exact multiplier) "The day-night temperature swing at any given location is typically about about a hundred times larger than the signal we are trying to find if were looking for an ice age"! So what?

Peter, the successful extraction of a signal from "noise" (which is comprised of other signals plus instrument error plus random noise) has been studied very extensively as a part of many disciplines.

The success in identifying the signal depends on many factors -- the size of the signal being searched for, the size of the other dominant signals, the number of other signals present, the accuracy of the instrument used to detect the signal, and the size of the random "noise".

Since you clearly don't understand the difficulties in extracting such a signal, you might profitably start with any good textbook on signals and noise. It is far from the trivial problem that you assume.

Bear in mind that it is not enough to say "the earth is warming, and therefore that is the 0.02°/yr signal I'm looking for."

Also bear in mind that the earth has cooled, at times for a couple of decades, while the CO2 increased. You need to extract the warming signal from these cooling times as well.

If in all of this you can point and say "that's it, right there, that's the 0.02°C per year increase I'm talking about", more power to you. No one else has been able to do so to date. If the problem were as trivial as you claim, we'd all have gone home long ago.

All the best,

w.

PS - yes, I know how temperature averages are produced. I'm also aware of the size of the error bars of those averaged temperatures. I assure you, they are much, much larger than the signal we are looking for. The fact that you can average temperatures and get an answer like, say, 11.3714 degrees does not mean that the answer is accurate to the nearest ten thousandth of a degree.

The problem in part is instrument accuracy. Although you can improve it a bit by repeated measurements, you cannot get more than about one more decimal by this process. Temperatures are measured to the nearest degree, so the best our averaging can do is maybe a tenth of a degree. But we are looking for a signal ten times smaller than that.

Another part of the problem is coverage. Our temperature coverage of the world is bad, and getting worse. We only have a third of the stations in the GISS network that we had in 1975. At present, we have an average of one GISS temperature station for every 85,000 square kilometres of land area. How accurate is a single temperature reading for each 85,000 sq. km.? A long ways from accurate enough to detect a 0.02°/yr signal, I'll guarantee you that.

Please study up on the difficulties inherent in the measurement of temperature, it should prove interesting reading. Thanks again for posting.

w.

11:54 pm  
Blogger Belette said...

Willis - its pretty weird the way you can drill down in a study you don't like to find something to quibble about, then come out with a howler like Since our weather records generally are only to the nearest degree, this is a long ways below instrumental accuracy. You are completely ignoring the averaging-reducing-noise stuff; indeed you're ignoring all the literature on producing global T trends. Read Jones et al. stuff; refs in the TAR, as ever.

10:32 am  
Blogger Belette said...

Willis - I think you must have read the wrong supporting material file. http://www.sciencemag.org/cgi/data/1115602/DC1/1 mentions relative humidity frequently.

2:57 pm  
Anonymous Willis Eschenbach said...

Belette, thanks for your comment. You seem mystified that instrumental accuracy would affect weather records. It seems that you may not be familiar with the concept of how instrument accuracy limits measurements, and how this is not improved by increasing the sample size. I can best explain this by looking at another kind of measurement device, a ruler.

Now, I have a mechanical pencil. The thickness of the lead is 0.7mm. Think about trying to measure the thickness of this lead using an ordinary ruler. I look at it and I say “about 0.8 mm”. OK, one measurement. Can we improve on that?

Sure we can. I ask you, and you say “0.7″, and someone else says “three quarters of a mm”, and so on. And for the first few additional measurements, our accuracy does improve. But soon a limit is reached.

We will never, for example, be able to detect the difference between two pencil leads that differ by a few thousandths of a mm by using an ordinary ruler in the ordinary way. No matter how many measurements we take. We can ask a million people, and have a statistical error of … just a sec, call the standard deviation of the readings say 0.1, error of the mean = SD/sqrt(n) … Standard Error of the Mean (SEM) ~ 0.0001 mm.

Doesn’t matter if the SEM is a ten thousandth of a mm, the results are not that accurate. The limit is not in the sample size. The limit is in the accuracy of the instrument. We still can’t tell the difference between the two pencil leads using a ruler.

Similarly, the fact that we can average temperature records to a hundred thousandth or something does not mean that our error is that small. Like with the ruler, the limit is not in the number of measurements taken -- the limit is in the accuracy of the measuring instrument itself.

w.

PS - calling another man's statement a "howler" is not generally done in the circles I move in. Other than being unpleasant, it is unwise. Like the spanish proverb has it, "Be careful of your words .. you may have to eat them ..."

6:19 pm  
Anonymous Willis Eschenbach said...

Belette, sorry I was not clear about the relative humidity. What I meant was that the supporting material does not say anything at all regarding T12 being a proxy for relative humidity. It makes no argument to support the claim, nor does it even repeat the claim.

w.

6:25 pm  
Blogger Belette said...

Willis - as to the measurement stuff, you're talking nonsense. I'd give it up: there must be better things to argue about. In fact its perfectly clear (http://www-pcmdi.llnl.gov/ipcc/project_detail.php?ipcc_subproject_id=417) that you don't believe it either.

As to T12: when you said "In fact, the term "relative humidity" doesn't appear in the document at all." I assumed thats what you meant. It seemed clear enough.

7:12 pm  
Anonymous Willis Eschenbach said...

This comment has been removed by a blog administrator.

8:12 pm  
Blogger Belette said...

Hi Willis. Sorry, you didn't take the gentle hint, so I've given you a rather stronger one. What you say about the measurement accuracy is not only wrong but also uninteresting, to me. You were better off with the humidity stuff. Try sci.env, or M&M, or somewhere.

9:45 am  
Blogger Barry said...

Actually Belette, what Willis says about accuracy is correct. If you had taken even an elementary level science course in chemistry or physics you would understand what he says is true. Willis knows his science. Anyone with any scientific training whatsoever should understand the basic principles that Willis so eloquently demonstrated to you. I imagine my post will make it to the trash bin as well.

You so rampantly assassinate Lindzen. Then when shown to be incorrect place your finger's in your ears and shout la, la, la. Just who is full of c**p? Typical of the character assassinating alarmist breed that refuses to look at all the facts. If the facts are contradictory or the methods shown inaccurate, those in this crowd always shift to ad hominem attacks to cover their tracks.

12:13 pm  
Blogger Dano said...

Barry,

it is interesting that you adopt as an argument that Wm should take an elementary science course. I take it you pulled this argument out of somewhere before looking at Wm.'s CV.

Willis and Dano have gone around and around many times, and I'd correct you, Barry, and suggest you consider Willis is a typical injuneer and fails to notice Lindzen's statements are always extremely carefully worded; perhaps this failing to notice is a product of disciplinarity...

Best,


D

4:31 pm  
Blogger Barry said...

Hi Dano,

Let me just say this. It doesn't matter what kind of scientist you claim to be. If you didn't get the part about accuracy of instrumental measurement which Willis tries to explain, then you must have been a poorly trained scientist.

I don't believe you could have graduated in a hard science field from my university without being able to understand this.

5:49 pm  

Post a Comment

Links to this post:

Create a Link

<< Home