The Phoenix official measuring station was located in a parking lot on Buckeye Road for many years – next to the NWS office at Sky Harbor. It has since been moved twice away from the pavement into the desert near Sky Harbor. Sorry I don’t know the exact years. One location was a few hundred meters NE of the E end of the N runway. Don’t know where it is now.

I suspect moving it has lowered our temps a couple of degrees.

John in Paradise Valley

The Phoenix official measuring station was located in a parking lot on Buckeye Road for many years – next to the NWS office at Sky Harbor. It has since been moved twice away from the pavement into the desert near Sky Harbor. Sorry I don’t know the exact years. One location was a few hundred meters NE of the E end of the N runway. Don’t know where it is now.

I suspect moving it has lowered our temps a couple of degrees.

John in Paradise Valley

The fundamental misconception that you have is that there IS some calibrated gold standard and other instruments are being given offsets to it. That’s not the case.

POPULATIONS of instruments are being adjusted based on populations of other instruments. And while the reference instruments are posited to be clear (or clearer) in terms of UHI contamination, they are not perfect to other effects (other confounding factors evident as noise). So even if you compare rural to rural, they are not identical in trend.

Therefore averages are used. Also, therefore some specific adjusted spots will be OVERCOMPENSATED FOR (as part of a normal distribution). And therefore some will be undercompensated. And you have to leave them, because otherwise, you are pruning undercompensated and leaving overcompensated. You’re pruning the data preferentially.

BTW, none of this is new!!! We’ve had this movied before! But the average commenter here doesn’t even get the basics. In some cases, doesn’t even read previous posts.

There are a lot of OTHER topics that ARE INTERESTING. For instance, why adjust, versus just using the reference population? Is the non-independance of adjusted stations noted? If there is minimal UHI impact, why go through an adjusting mechanism? If there is minimal UHI impact, does that mean that it’s not that prominent (as a time dependant influencer of the global average) or does it mean that the reference populations are similarly biased by small scale UHI? These are all the obvious interesting next scale questions. But we can’t even get there with the hoi polloi idiocy of the average skeptic commenter. We can’t get there with Steve McI not playing fair and “cherrypicking points of criticism” (and in this case in a method that has already been shown before several months ago to be sophistry…to be argument for effect versus understanding and exploitation of MISUNDERSTANDING such as Bill’s for effect.

Let’s be GOOD SKEPTICs. Not dummies. Not sophists.

I understand / misunderstand instrument corrections to be applied so the corrected reading represents the actual physical state of the thing measured. I picture in 1900 a wooden shelter on the lawn of the sewage treatment plant (far) out of town. I can imagine the sun heats the shelter and the LIG [liquid in glass] thermometers inside are warmer than the air so you would want to apply a negative correction to the instrumental readings to get the actual temperature of the air. But what circumstances would lead one to believe the thermometers were ever cooler than the ambient air? Can anyone explain the physics of this?

Did the scientists of 100 years ago realize their thermometers were not accurately measuring air temperatures? Did they correct data? In what year did thermometer corrections like these begin? Did someone place a “gold standard” instrument next to one of these shelters and find some sort sf systematic difference that would justify adjusting all of the temperatures for a whole year? Century?

[I] also wonder[s] if anyone has a physical, climatological or instrumental reason the measured / computed difference between the air and the thermometer should change linearly (and stepwise) with time?

If there is such a mechanism, did anyone notice it change sign in 1980?

Source web page: Climate Audit – by Steve McIntyre » Positive and Negative Urban Adjustments ( http://www.climateaudit.org/?p=2815 )

For the other commenter: if you don’t know who Burger is…you’re clueless. Get hot.

Posted by: TCO | February 29, 2008 at 05:47 PM

What a singularly nasty and foolish comment. JohnV has been working with Steve McIntyre on code puzzles. As to TCO and Gerd Burger getting information, I have never seen either name on CA, so I don’t know where they are asking for this info.
Fists Sreve McI is claimed to be an oil company shill, then this reversed insulting comment.
If I were Steve McI, I think I’d sue, but, anyway, Warren, can you please block this foul-mouthed object and spare the rest of us from this muck?

It’s ridiculous. It might cause a negative jump, but certainly not a trend (except in rare instances).