Whitewash and bias, Painting over the historical record

[Chris Knight]

Why is is a different process - I've got a satellite receiver here and if you select the temperature measurement view it will display the temperature of the cloud tops if there is cloudcover and the temperature of the ground if there is not. That same cloud top temperature is used by the satellite to define where cloud is and at what height it is.

Calibration of cloud height temperatures are presumably compared to airborne sensors, not ground stations.

And now we got to use the right type of paint. I doubt very much a white washed one than a painted one would show much difference if any to the human eye. For the record our last one came from Castella and that was finished with gloss paint not whitewash.

Next thing we'll be talking about is people wearing glasses not reading correctly

Not to the human eye, but to the thermometric recorder within the box, if you read the original post with your correct glasses on!

[Paul]

Calibration of cloud height temperatures are presumably compared to airborne sensors, not ground stations.

I really do think you're barking up the wrong tree on this one, as I understand it satellites are not calibrated against ground stations, they measure temperature in a very different way to what you expect and in truth that is probably the place to look if you're wanting to show that satellite data isn't infallible. This wikipedia article explains it a bit:

http://en.wikipedia.org/wiki/Satellite_tem...re_measurements

[Chris Knight]

What are we talking about then? Are you saying this alleged paint effect is in fact large?

about 0.5deg C rise in the twentieth century, about 0.17 deg C per decade since 1970, according to the figures

[Devonian]

On the LWC see all the posts in the 30C this summer thread, especially posts from the likes of John Holmes (who also greatly respects the UKMO for obvious reasons)

On theproblems of standardisation and homogeneity in the Met Office Hadley CET, there are many papers and discussions about this issue. Check out:

(Warning - the Met Office paper is in pdf and lengthy, but well worth careful reading)

http://www.climate-uk.com/CETcheck.htm

http://www.climate-uk.com/CETcheck.htm

http://www.metoffice.gov.uk/research/hadle...CTN/HCTN_50.pdf

Even the greatest fans of the Met Office, like myself, struggle to disagree with Philip Eden's critique:

Since Professor Manley’s death the Meteorological Office seems to have become the self-appointed guardian of the CET series, although one wonders whether it is a guardianship of which Manley would have approved. Their continuation of the series from 1974 onwards uses observations from a variety of stations in the English Midlands (including the southeast Midlands); neither Oxford nor stations on the Lancashire Plain have been utilised, and for 30 years one coastal site was included. It is therefore manifestly not the same series, and large inhomogeneities are apparent.

The Hadley Centre's CET calculation has recently undergone a major change, involving the replacement of several of the

contributing stations. Their series is now based on Stonyhurst (Lancs), Pershore (Worcs) and Rothamsted (Herts), all of

which are Campbell Automatic Weather Stations. The Philip Eden series continues to emulate Manley's original work

which calculates the mean between the Oxford district and the Lancashire Plain, and no changes have been introduced

to this series in recent months. You can draw your own conclusions as to the efficacy of the Hadley Centre's change.

Anyway, whilst this does relate in terms of standardisation we had better be careful not to wander off course.

This is, as you say, rather OT. But I think Philip is talking about how data is used rather than data itself. I'm halfway to agreeing with Philip, but, again, it's about how the data is used (Philip isn't saying the data is faulty), not obtained.

This thread is about how data is obtained.

I will read the .pdf.

about 0.5deg C rise in the twentieth century, about 0.17 deg C per decade since 1970, according to the figures

The question was about the paint effect. You say it is .17C per decade? I think not. How big is the paint effect iyo?

[Chris Knight]

I really do think you're barking up the wrong tree on this one, as I understand it satellites are not calibrated against ground stations, they measure temperature in a very different way to what you expect and in truth that is probably the place to look if you're wanting to show that satellite data isn't infallible. This wikipedia article explains it a bit:

http://en.wikipedia.org/wiki/Satellite_tem...re_measurements

Try searching google rather than wikipedia - caveats over Wikis are well known -

google on calibration of satellite radiometer to see how its done.

This is, as you say, rather OT. But I think Philip is talking about how data is used rather than data itself. I'm halfway to agreeing with Philip, but, again, it's about how the data is used (Philip isn't saying the data is faulty), not obtained.

This thread is about how data is obtained.

I will read the .pdf.

The question was about the paint effect. You say it is .17C per decade? I think not. How big is the paint effect iyo?

Apologies I was being flippant - that is just one of the many estimates of the rate of global warming. I have no data, thus no valued opinion, it needs looking into.

[The PIT]

I'm just thinking how much paint you have to over paint over the years to make such a huge difference.

[West is Best]

This is, as you say, rather OT. But I think Philip is talking about how data is used rather than data itself. I'm halfway to agreeing with Philip, but, again, it's about how the data is used (Philip isn't saying the data is faulty), not obtained.

I'm not actually sure the two things are completely separate or separable. Where you site a station has huge implications for how you measure ... the history of the MetO's use of the CET seems to me to centre around this, not merely in terms of things like urbanisation but also in attempting homogeneity with stations and readings from the past which themselves may well be suspect for various reasons.

On the other hand, one specfic aspect of this surrounds the paint on the SC, so fair enough if we stick to that! What did they do in the C17th ...?!

Edited October 14, 2007 by West is Best

[Paul]

Try searching google rather than wikipedia - caveats over Wikis are well known -

google on calibration of satellite radiometer to see how its done

Lol, I'm well aware of the issues with wikipedia, but used that as an example as from what I can see it contains good information.

[Stratos Ferric]

Looks simplistically good doesn't it? And then you stop and think, 'hmmmm .... don't think they had satellites in the C16th'. Satellites have only been measuring global temperatures in a matter of years. Sea temperatures have not been properly and systematically measured over sufficient time. Arctic ice has indeed hit a minimum this year, but antarctic ice which accounts for 90% on the planet hit a maximum this summer (albeit with the same caveats over measurement). Snow cover is untested as a theory of proof of GW, and is as patchy science as the alleged snow cover.

The reason many of us use the CET as a benchmark is because it is long lived, but it's therefore entirely valid to raise issues about the measurements.

The more you look at the so-called solid science, the more valid questions are raised.

WiB, Chris's point isn't about calibration of telemetry. You'll be suggesting the polar stationary satellites have had their optics changed next, and that the ice isn't actually melting.

...

Then maybe we can examine the facts rationally.

Aside fromn the fact that I don't think 50,000 people looking at this would have missed thius chink, can you clarify one thing.

Are you actually suggesting that the climate is not warming, and that everythiung we're seeing in the numbers is down to faulty measurement?

...I have no data, thus no valued opinion...

At last!

[Paul]

Just out of fairness, it's probably best to use quotes from other people in the context they were meant, what Chris Knight actually said was:

I have no data, thus no valued opinion, it needs looking into

That last bit is fairly important I think!

[West is Best]

You'll be suggesting the polar stationary satellites have had their optics changed next, and that the ice isn't actually melting.

It isn't in antarctica where it's been at a record high according to CT. Anyway, going very off topic lol!

[Guest Viking141]

Just out of fairness, it's probably best to use quotes from other people in the context they were meant, what Chris Knight actually said was:

That last bit is fairly important I think!

Absolutely Paul, Straw Man point and quite probably a Burden of Proof Fallacy as well ("absence of evidence is not evidence of absence") and also an implied if not actual ad-hominem. Can I again appeal to people to stick to arguments of fact and science leaving aside any personal remarks which add absolutely zero to the "debate?"

[Richie V]

At the rates currently proposed, yes, but I do not doubt that there is warming going on, it has been since the last ice age, with various ups and downs. I doubt the early 20th century data is as warm as it should have been, and I doubt the current temperatures are as high as the records show, on the basis of artificially introduced bias as in #1 above.

I agree. The problem I have is wether It's day or night my temp readings are always at least a clear 1C lower than the "experts" readings, and sometimes much more!. I have a verity of single bulb mercury thermometers and 15 of those oregon scientific white 30 sec pulse electric thermometer sensors 433Mhz, all vary no more than + - 0.2C on each other.

I record in the same place all the time IN THE SHADE with no screens or boxes at an elevation of 2.5 meters. I've felt for a while that the met office and various tv forecasts always over do their max temps, Not very scientific I know!

[Chris Knight]

All I can say that the kit needs to be maintained properly. So you'll need to keep it painted as that will reflect the heat and also prevent the wood rotting. Comments have been about the airflow. There will be airflow through the screen but this will also depend on the amount of breeze outside the screen somewhat. A still day and a screen that's not been painted which is standing in the full hot sun would more likely than not give a slightly higher reading.

Sorry, TP, I missed your post in the flood. Before modern paint, the kit had a standard coating of whitewash, which has radically different heat response physics to modern paint as explained in the first post. White to the eye is not white to a radiation sensor such as a thermometer. White paint reflects visible wavelengths, but is transparent to infrared. Feel how warm your paintwork gets, in the sun and compare that to the feel of whitewash under similar sun, if you can. There is a noticeable difference, especially if the whitewash gets damp. Wood is a good insulator, but variable if damp or dry, if dense or light timber is used. Averaged out over thousands of global stations, under different conditions, you might expect that indifferently standardised screens would be least compromised in the tropics, and most in the temperate and arctic regions, over the time that global records have been have been amassed, averaged and corrected for known bias.

The last comment: "a screen that's not been painted which is standing in the full hot sun would more likely than not give a slightly higher reading" applies equally to a freshly repainted screen, if the coating is transparent to IR.

I agree. The problem I have is wether It's day or night my temp readings are always at least a clear 1C lower than the "experts" readings, and sometimes much more!. I have a verity of single bulb mercury thermometers and 15 of those oregon scientific white 30 sec pulse electric thermometer sensors 433Mhz, all vary no more than + - 0.2C on each other.

I record in the same place all the time IN THE SHADE with no screens or boxes at an elevation of 2.5 meters. I've felt for a while that the met office and various tv forecasts always over do their max temps, Not very scientific I know!

I think that this is by far the simplest option - shade the Screen from direct sunlight at all times of the year during daylight, expose at all times during the night. But that doesn't correct any possible historical bias, sadly.

Edited October 14, 2007 by Chris Knight

[Stratos Ferric]

I agree. The problem I have is wether It's day or night my temp readings are always at least a clear 1C lower than the "experts" readings, and sometimes much more!. I have a verity of single bulb mercury thermometers and 15 of those oregon scientific white 30 sec pulse electric thermometer sensors 433Mhz, all vary no more than + - 0.2C on each other.

I record in the same place all the time IN THE SHADE with no screens or boxes at an elevation of 2.5 meters. I've felt for a while that the met office and various tv forecasts always over do their max temps, Not very scientific I know!

Yes, but the BBC tend to show city temperatures, as evidenced, particularly on cold nights, by the invariably rider "probably a few degrees lower than this out in the country". In any case, you don't calibrate instruments against forecasts.

...Averaged out over thousands of global stations, under different conditions, you might expect that indifferently standardised screens would be least compromised in the tropics, and most in the temperate and arctic regions, over the time that global records have been have been amassed, averaged and corrected for known bias.

...

But you continue to labour under tow presuppositions which I am certain will not test out in practice.

1 - that nobody checks data for relative consistency over time - very easy nowadays given processing power available and exactly the sort of routines that banks use to spot irregular activity on credit cards; and

2 - that the error of any effect you're mentioning (and I very much doubt that it's significant anyway) develops in all adjacent places consistently over time, so that the error becomes undetectable.

You still haven't answered the question above. Are you suggesting that all recent warming is measurement error?

[Chris Knight]

Yes, but the BBC tend to show city temperatures, as evidenced, particularly on cold nights, by the invariably rider "probably a few degrees lower than this out in the country". In any case, you don't calibrate instruments against forecasts.

Isn't Chassisbot out in the rural wilds of south Barnsley? Sorry OT

[Stratos Ferric]

Isn't Chassisbot out in the rural wilds of south Barnsley? Sorry OT

Well, if he's in suburban Barnsley he still won't be as warm as an urban core: gardens, smaller stone surfaces etc, freer movement of air.

Are you deliberately not answering my question re warming?

[Richie V]

Isn't Chassisbot out in the rural wilds of south Barnsley? Sorry OT

Fairly high up, I'm at J38 M1 if this means owt to anyone. 2 miles from Tarn centre

[Chris Knight]

Yes, but the BBC tend to show city temperatures, as evidenced, particularly on cold nights, by the invariably rider "probably a few degrees lower than this out in the country". In any case, you don't calibrate instruments against forecasts.

But you continue to labour under tow presuppositions which I am certain will not test out in practice.

1 - that nobody checks data for relative consistency over time - very easy nowadays given processing power available and exactly the sort of routines that banks use to spot irregular activity on credit cards; and

2 - that the error of any effect you're mentioning (and I very much doubt that it's significant anyway) develops in all adjacent places consistently over time, so that the error becomes undetectable.

You still haven't answered the question above. Are you suggesting that all recent warming is measurement error?

I answered in the post Chassisbot referred to in your top reply on your last post. Warming is currently going on. By how much in the 20th and and 21st centuries, I believe the biases in post #1 obscure the real picture. Until the ground station data is verified against a better standard, and the corrections applied consistently to the record, if at all possible, the record in my opinion, for the reasons given, remains in error.

And then we shall need to refine P. Brohan, J.J. Kennedy, I. Harris, S.F.B. Tett and P.D. Jones, Uncertainty estimates in regional and global observed temperature changes: a new dataset from 1850. J. Geophys. Res, 111, D12106, doi:10.1029/2005JD006548. (pdf 1.2Mb)

Unless my responses are being bumped off for being OT, which they are. The calibration is not in question, the effects of the change from historical housing of instrumentation on the data is.

Edited October 14, 2007 by Chris Knight

[Devonian]

I answered in the post Chassisbot referred to in your top reply on your last post. Warming is currently going on. By how much in the 20th and and 21st centuries, I believe the biases in post #1 obscure the real picture. Until the ground station data is verified against a better standard, and the corrections applied consistently to the record, if at all possible, the record in my opinion, for the reasons given, remains in error.

And then we shall need to refine P. Brohan, J.J. Kennedy, I. Harris, S.F.B. Tett and P.D. Jones, Uncertainty estimates in regional and global observed temperature changes: a new dataset from 1850. J. Geophys. Res, 111, D12106, doi:10.1029/2005JD006548. (pdf 1.2Mb)

It's no good going around saying the work of eminent others should be refined or that the temp record remains in error if you're not prepared to do the necessary research and put a figure on that error. It looks look you're trying to run before you've taken your first step.

[Chris Knight]

It's no good going around saying the work of eminent others should be refined or that the temp record remains in error if you're not prepared to do the necessary research and put a figure on that error. It looks look you're trying to run before you've taken your first step.

Are you saying that science shouldn't move on? HADCRUT3 is a refinement of previous versions. I do not presume to say I could do better, having at length pointed out why the current record may be questioned. But I guess there are eminent others out there who may be interested in setting the record straight.

[West is Best]

It's no good going around saying the work of eminent others should be refined or that the temp record remains in error if you're not prepared to do the necessary research and put a figure on that error. It looks look you're trying to run before you've taken your first step.

I'm not sure that's really fair to Chris, nor that it stands up academically.

It's perfectly acceptable in academia to question things, even to expose flaws in an argument, without producing the definitive research paper of your own. The world wouldn't advance its knowledge much if we all had to wait to produce the Summa Theologica before uttering a word of critique.

[Chris Knight]

Are you saying that science shouldn't move on? HADCRUT3 is a refinement of previous versions. I do not presume to say I could do better, having at length pointed out why the current record may be questioned. But I guess there are eminent others out there who may be interested in setting the record straight.

I am not suggesting that the record is a straight line, flatline or any other line here

[BrickFielder]

A great deal of work has been done to align satellite tropospheric measurements to radiosonde measurements. This means as far as possible satellite calculated temperatures match up to actual measurements taken with balloon thermometers. One thing that has become evident is that tropospheric temperatures do not seem to have risen as much as surface temperatures. A number of theories have been put forward for this including paint , heat island affects,lack of polar and sea measurements, but to me the most likely seems to be dust in the lowest ten meters of the atmosphere. Removal of forest and greater activity by humans has increased dust levels. What ever the reason for the discrepancy surface based temperature records whilst accurate are thought to be less accurate in portraying global warming when compared to satellite measurements.

[West is Best]

BF - do you think sea surface measurements are actually worth anything at all? I've become sceptical about their efficacy and suspect they are incredibly random. I read some articles on this but haven't the time to look them up right now.

Edited October 14, 2007 by West is Best