How not to measure temperature, part 63

One of the strangest things I’ve learned in the past year about the US Historical Climatological Network is the propensity for placement of weather stations at sewage treatment plants.

The reason of course has to do with putting a thermometer at a facility that is staffed 7 days a week. That thermomter must be manually read once a day and the readings transcribed into a logbook. Waste Water Treatment Plants (WWTP’s) fit that requirement (as they have an operator on duty, often 24/7) but they themselves are their own mini islands of waste heat and humidity, especially in winter and overnight. Yet, a significant portion of the US climate data comes from these locations.

Some have grassy areas where a climate monitoring station could be placed, such as the one in Morrison, IL, and you’d think they would place it there, away from the sewage tanks. Unfortunately, no.

Click for a larger image, additional photos available here at

My sincere thanks to volunteer surveyor Scott Finegan for these photos.

The Stevenson Screen housing the thermometer is about 5 feet away from each tank, while the concrete building in the background is some 50 feet away. You’d think that they could have placed the station a little further away. Again, as we’ve seen time and time again, the placement is not often about the best location, it is about convenience for the observer.

The GISS graph of temperature over the station history shows a fairly strong warming trend from about 1980 to the present. The question is, how much of that is from increased throughput of the sewage treatment plant responding to population growth, and how much of it is climate change?

Click for source graph from NASA GISS

According to NCDC’s Multi Metadata System database, this station has been at this location since at least 1948, even though a lat/lon accuracy update makes it appear to have been relocated in 1997, it has in fact been at this location all that time.

A nearby station, 25km away, Clinton, IA, is also in the GISS database and shows less of a trend during the same period:

Separating a climate change signal from the waste heat (and increasing effluent volume of the WWTP due to population growth) may not be a simple matter to disentangle. Since each WWTP has different conditions, coming up with a blanket correction would not be easy. Therefore, since the USA is highly oversampled spatially with weather stations that report daily data which can used for climate, it would be prudent in my opinion, to remove stations like this from the climatic database since the data produced by USHCN stations at WWTP’s may not be truly representative of climate.

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Pierre Gosselin
May 29, 2008 12:35 am

Looking at the photos, what the heck is that grating under the station?
And I always wondered about what kind of material is used for the roof of the Stevenson screen. Is it plastic, metal, wood…? Especially in the summer the material for (and condition of) the roof could have a significant positive heating bias.

May 29, 2008 12:46 am

Wait a second… are you saying this data is CRAP? =) Sorry, couldn’t resist.

May 29, 2008 2:36 am

Global warming may well be caused by an increase in hot showers by teenagers.

May 29, 2008 3:53 am

This is especially bad. Much worse than near asphalt. A parking lot may increase in usage, and thus temperature, over time. But a water treatment plant certainly will. You should see both more heat and humidity emitted and both more energy absorbed and trapped.

May 29, 2008 4:24 am

[…] With thanks to Anthony Watts. […]

May 29, 2008 4:46 am

Are there any photos or specs of/for the Clinton station? Is it near anything?
On a similar vein, I’ve been watching the hourly readings from both O’Hare and Palwaukee fields in Illinois (using my handi dandy Storm Predator software) for some time now. I’ve been also recording measurements taken from three sources around my home including two from different LaCrosse weather stations and one from a clinical thermometer designed for chemistry applications.
Although the readings from my abode and Palwaukee are generally in sync, the O’Hare reading varies greatly depending on wind speed and direction. At first I was puzzled by the large, seemingly random variance.
But then I noticed that when the wind was from the east it would bring Lake Michigan’s cool temperatures over my area, but apparently mixes that same cool air mixes with Chicago’s hot urban air (especially when the city council is in session ) and decidedly impacts the temperatures by the time they reach O’Hare. At least that’s my theory so far.
Are there any photos/specs posted on the O’Hare location?
Jack Koenig, Editor
The Mysterious Climate Project

May 29, 2008 5:16 am

Addendum to my previous post on the temperature variances between O’Hare, Palwaukee field, and my house.
The distance between O’Hare and Palwaukee is ~8.8 miles due north as the birdie flys.
The distance between O’Hare and my house is ~15.4 miles NNE as the birdie flys
The distance between Palwaukee and my house is ~8.9 miles NE as the birdie flys.
Jack Koenig, Editor
The Mysterious Climate Project

Chance Metz
May 29, 2008 5:27 am

This really stinks,no pun intended but it shows why some data is questionable.

May 29, 2008 6:06 am

Could you redo the first graph so they have the same vertical scale? That would make it easier for me to compare them. It is obvious to me that 1998 is different, but I am not so sure of the others. — John M Reynolds
REPLY: Talk to GISS, that what they output. I find it annoying as well.

Evan Jones
May 29, 2008 7:56 am


May 29, 2008 10:07 am

All this reminds me of an episode of Gilligan’s Island. Season 2, episode 6, called “Quick Before it Sinks”, “The professor mistakenly believes that the island is sinking”.
The professor was using a stick in the water (to measure water level). Gilligan was using the stick to anchor a fish trap, and started moving the measurement-stick to deeper water (to catch bigger fish). Very funny…

Scott Finegan
May 29, 2008 10:34 am

The grating is 6+ feet from the Stephenson Screen. Look at the other pictures, for a side view.
Clinton is on the Mississippi.
Clinton is listed in Iowa, yet is measured from the PO in IL (in your spreadsheet).
NOTE —Clinton, IL. is about a third of the way down the state, near but south of Bloomington, IL.
REPLY: It is not a USHCN station, but a GISS station and the nearest to Morrison. See this list of nearby stations within a 200km radius of Morrison:

Scott Finegan
May 30, 2008 5:18 am

Some days I can screw up the simplest of things.
Just before the Clinton #1 graph you wrote
“A nearby station, 25km away, Clinton, IL, is also in the GISS database and shows less of a trend during the same period:”
Should say…
A nearby station, 25km away, Clinton, IA, is also in the GISS database and shows less of a trend during the same period:
REPLY: Fixed, thanks

May 30, 2008 11:32 am


Again, as we’ve seen time and time again, the placement is not often about the best location, it is about convenience for the observer.

Uhm, manual reading the temp between two huge pools of feces? You call that convenience?

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