Monday, February 15, 2010

Climate Change Skepticism: You're doing it wrong

The following is a popular picture used by climate change skeptics to attempt to show that there's something seriously wrong with the the surface temperature record which is used to show that the world is getting hotter.

It appears to show that two weather stations with Stevenson screens are situated right at the end of the runway of Rome Ciampino. It's not hard to put two and two together and see that the wash from the engines of departing jets would cause the temperature indicated by the thermometers to be much too high.

Between the two Stevenson screened boxes is an automated weather observation station used by the airport. So it too would be affected by aircraft wash.

Now, any pilot will tell you that knowing the barometric pressure at the airport (as reported by the QFE code) and the local temperature are vital data in setting the altimeter correctly when landing. Aircraft altimeters work on atmospheric pressure and when approaching the airport the pilot is told the current pressure so they can set their instrument correctly.

The temperature also matters because it can affect the altimeter reading when the weather is cold. Pilots need to know both accurately to land safely. So does it seem likely that at Rome airport the weather station is heated by aircraft wash?

Of course not, and if you zoom out from that picture and orient it North/South (rather than South/North) you'll see a different picture:

You can make our the stations near the top left-middle of the picture. They are far from the runway and positioned near an aircraft parking area.

If you are going to be a skeptic go with the Wikipedia definition: A scientific (or empirical) skeptic is one who questions the reliability of certain kinds of claims by subjecting them to a systematic investigation.. One picture does not a systematic investigation make.

Update That picture was alluded to in a Sunday Times article this weekend:

Watts has also found examples overseas, such as the weather station at Rome airport, which catches the hot exhaust fumes emitted by taxiing jets.

And The Daily Telegraph has a similar story:

A weather station at Rome airport was found to catch the hot exhaust fumes emitted by taxiing jets.

That statement is inaccurate. The weather station is not near a taxiway, it's near a parking area. And not even a parking area next to the terminal building.

And even if it was, one bad thermometer doesn't mean climate change can be thrown out the window.


Simon Zerafa said...


I do have to wonder if the "heat island" effect does have an effect on reported weather conditions.

Does this eventually impact climate models or are these effects taken into account?

Kind Regards


Peter Risdon said...

"... subjecting them to a systematic investigation" is exactly what Anthony Watts has been doing, though, with his surface stations project. Could your criticism of sceptics not be made of your own post?

Béla Pátkai said...

The two photos are not identical, they are two different planes. Anyway, it is true that this is not an evidence.

John Graham-Cumming said...


The problem with is that it doesn't actually give any useful data. For example, all it's doing is taking pictures of where the stations are located and then making sure that they meet NOAA rules. They don't, AFAIK, actually take any temperature measurements to help understand the effect of their findings.

Real Climate addresses this issue:

Peter Risdon said...

John: "They don't, AFAIK, actually take any temperature measurements to help understand the effect of their findings."

That's my understanding too. But since the purpose of the survey is just that - to survey the sites and compare them to the NOAA rules (which a frighteningly large number score badly on) - this cannot really be a reasonable criticism.

It does, though, surely amount to a "systematic investigation".

A broader point is that criticism of Watts' survey on the grounds that it doesn't do something it does not set out to do is characteristic of a mission to discredit rather than engage with his activities.

Sean T. McBeth said...

The problem isn't one bad thermometer, it's that the vast majority of weather stations are bad.

John Graham-Cumming said...

@Peter That's fair comment, but I don't believe that the Surface Stations project provides much useful information.

Peter Risdon said...

John, I don't want to worry at this beyond the point where it's interesting, but isn't it useful to have established that there may be problems with the surface record, without having been equipped to quantify these possible problems?

veronica_milvus said...

But it isn't just one climate station. Many other stations are in areas recently urbanised and therefore now subject to urban heat island effects. Since 1990, 4500 out of approximately 6000 surface stations have been excluded from the dataset used to calcuate global average temperatures. Those omited are generally in least accessible, rural and higher altitude areas, more likely to be cooler than those remaining in the calculation. And then the data from these stations is adjusted and homogenised and all the adjustments seem to be upwards. See Watts Up With That? for specific details of the problems.

John Graham-Cumming said...

Yes, it's interesting to know, but without analysis it could just be noise. The fact is that noise and uncertainty are the climate change denier's friend, they are not the scientists friend.

Phil said...

"On the reliability of the U.S. Surface Temperature Record"
The above links to the paper of the same name by NOAA's Matthew J. Menne et al. recently published in the Journal of Geophysical Research, and has additional useful commentary.

tz said...

Am I completely alone for calling for a timeout and do-over for the whole thing?

Instead of "peer review" we've had obfuscation, coverup, and soft censorship.

Drag all the data out into the open at a common website, with enough detail for supporters and critics alike to agree on what is or is not valid, create models and debate them, and see what comes out with a completely open process and the various results.

Of course being in a panic is a lot more fun. Burning witches at the mere accusation is far easier than establishing cause and effect. OTOH, the mideval warm period ended about the time we started burning witches...

Edward said...

John - I suspect the goal of was to identify if there is problem or not. Then, if there is, is further investigation warranted? The findings of suggest that further investigation of accuracy of the surface network in the U.S. is needed.

The suggestion to begin measuring temperatures and actual effects, if any, at affected stations is a good one. But may be difficult to do solely with volunteers who often cannot get access to the specific location. Perhaps the result of will be funding to do a "proper" survey. Roger Pielke, Sr, at the Univ of Colorado, has done such a survey in Colorado and did find some problems there.

Charlie said...

So you are happy with the position of the Stevenson screen, so near the large expanse of concrete?

It appears to me that the guide lines on the tarmac would have a aircraft headed for that spot putting its engine exhaust directly on the Stevenson screen as it turns into the park pad. Is this acceptable station location per your standards?

CM said...

John, when the Ciampino photographs first came to my attention almost a year ago at WUWT, they were accurately described as being close to a jet parking area, tarmac and a truck parking lot. (Link to

The words ‘right at the end of the runway’ were nowhere in sight.

silburnl said...

"The findings of suggest that further investigation of accuracy of the surface network in the U.S. is needed."

Which investigation has been done, see the cite to the Menne paper two posts prior to yours. Menne's conclusion was that badly sited stations per Watts' characterisation have introduced a slight cooling bias to the monitoring network.

If Watts has data that will overturn this result then he needs to put a paper together in response. Meanwhile he should think about submitting a comment on Menne's paper to JGR whilst his paper is being prepared for publication.


Frontiers of Faith and Science said...

Do you think the jets in the parking area do not run up their engines to move out of the parking area? Are they towed in or out?
But to the more interesting point, made in your responses, that the temp site survey is
It is a survey to assess if the temp record is gathered according to established standards. Surely, if one is claiming accuracy and validity and credibility, one would be interested in quality of data.
To sit back and pooh-pooh a wide ranging survey that shows significant problems as meaningless is not moving the issue forward at all.
In any industry that requires accurate data, a survey like this would be of value and welcomed by those caring about accuracy and valid results.
But not, apparently, claimte science.

Professor Mandia said...

So how does the ocean exhibit UHI or a microclimate? Strangely enough, the trend in ocean temps derived by satellite data closely matches the trend reported from the global surface data.

A rising tide lifts all boats - even artificially warmed boats.

DavidB said...

I'm curious to know how you can 'zoom out' of an oblique view and get a vertical view. Have you patented that?

DavidB said...

I'm curious to know how you can 'zoom out' of an oblique view and get a vertical view. Have you patented that?

apolytongp said...

There's a habit of the skeptics doing this, that distresses me. Becuase I am sort of "on their side". But when I see Watts reccurrently make errors and fail to acknowledge them. When I see McI with his Tucson airport errors and truculence to correct...then I just get almost physically disgusted at my own side.

Guys like you, JohnV, EdZ are way more my taste. I honestly think you would report an insight whichever side it helped. I don't trust McI to do that. REally I DON'T. And Watts is not just biased...he's DUMB. Really.