This is why you don't put an official NOAA temperature sensor over concrete

You’d think the answer would be obvious, but here we have a NOAA operated USHCN climate station of record providing a live experiment. It always helps to illustrate with photos. Today I surveyed a sewage treatment plant, one of 4 stations surveyed today (though I tried for 5) and found that for convenience, they had made a nice concrete walkway to allow servicing the Fisher-Porter rain gauge, which needs a paper punch tape replaced one a month.

Here is what you see in visible light:

 

Here is what the infrared camera sees:

Note that the concrete surface is around 22-24°C, while the grassy areas are between 12-19°C

This station will be rated a CRN5 by this definition from the NOAA Climate Reference Network handbook, section 2.2.1:

Class 5 (error >~= 5C) – Temperature sensor located next to/above an artificial heating source, such a building, roof top, parking lot, or concrete surface.”

Now a caveat: There had just been a light rain, and skies had been overcast, it had just started to clear and you can see some light shadows in the visible image. Had this rainfall and overcast not occurred, the differences between grass and concrete temperatures would likely be greater. Unfortunately I was unable to wait around for full sun conditions. The air temperature was 58°F (14.4°C) according to my thermometer at the time.

Here is another view which shows the NOAA sensor array, the sky, and the evidence of recent rainfall as evidenced by the wet parking lot:

Why NOAA allows installations like this I’ll never understand. And this station is a USHCN climate station of record, used in who knows how many climate studies.

I’ll tell you more on this station and others I surveyed tomorrow.

 

0 0 votes
Article Rating

Discover more from Watts Up With That?

Subscribe to get the latest posts sent to your email.

103 Comments
Inline Feedbacks
View all comments
Evan Jones
Editor
April 21, 2008 9:24 pm

Well I think that adds some additional buckshot to what the Rev (and i) have been banging on about concerning the LeRoy CRN “estimates”.
Not to mention the Yilmaz (2008) and LaDochy (Dec. 2007).
And the Rev’s earlier accounting of the “Baltimore rooftop” comparisons.
A picture is worth a thousand words! (And I will indeed be adding a few thou on this particular subject!)

April 21, 2008 9:38 pm

The color on the MMTS shield is a shade of purple that, from eyeballing the color scale, leads me to think it is 1/3 of the way from 10 to 24, or about 14.5C. When you say that “The air temperature was 58°F “, does that mean the air temperature at the MMTS, or is that a representative average of the surrounding area?
If it’s the former you could have measured the microsite bias at this station if you wanted to, but you didn’t. Take the temperatures over the concrete, and then over the grass and show us how much they changed.
If the latter, then we can reasonably conclude that the microclimate issues with this station are small.
REPLY: I don’t think you can conclude that at all and I think you miss the point. There’s a standard, (CRN1-5 or COOP 100 foot rule, take your pick) that has been ignored. There’s good reasons for such standards. Though given your defense last year of your UofA USHCN station in the parking lot, I suppose I can see why you don’t see much issue here. Your defense of the UofA station suggested you don’t think siting is important.
Unfortunately, I didn’t have a portable calibrated thermometer and portable aspirated IR shield with me, which would be required to do a proper job of air temperature measurement. The air temperature value I gave came from the vehicle thermometer, as I drove up. I’d call it anecdotal.
You aren’t the first person to ask why comparative temperatures aren’t being taken at these sites at time of surveys. The answer is that I (and volunteers) can’t do the job of a complete study when often there are only a few minutes of time at these stations. A couple of spot readings isn’t enough.
But the new datalogger and shield (see previous blog post) I’ve designed has just completed its first parallel trial at a COOP site, so we’ll see what it says when I get back and get the data from the COOP.
This really should be NOAA’s job of understanding microsite bias issues. And it wouldn’t be needed at all if exposure/placement standards were adhered to. But they aren’t paying attention or even enforcing their own 100 foot rule.
The key here is not any instantaneous air temperature, but the average of Tmax/Tmin for the day. What does that heat sink of concrete (and the environment of the sewage treatment plant) do for the Tmin which is much more capable of being affected than Tmax and how does that affect the daily average?
Its all about artificial heat sources. That concrete mass releases heat slowly. The IR shows that even the light rain didn’t do much for cooling it similarly to nearby things. We don’t know what the picture looked like before the rain (which would affect the low mass gill shield more than the concrete) so how do you know it wasn’t reading higher before? How do you know that the air temperature will read accurately in full sun with no rain? I don’t and you don’t. But the siting standard suggests there is an issue. The IR picture shows the heat sink effect clearly.
The point here is siting: don’t put a thermometer next to a heat sink like a walkway, driveway, active parking lot, or building and you don’t have to do the disentanglments in the first place.

Jennifer Marohasy
April 21, 2008 9:50 pm

Fascinating.

Philip_B
April 21, 2008 11:41 pm

Note how weathered the concrete is. Its albedo will have changed substantially from when it was laid, introducing a spurious cooling trend to daytime temperatures and probably a warming trend to nighttime temperatures.
That picture goes a long way toward explaining the long term decrease in diurnal range seen in the temperature record.
http://climate.uvic.ca/common/papers/cldyn.2003.20.435-445.pdf
(read it for a description of long term changes in diurnal range)

kim
April 22, 2008 12:59 am

R2D2
====

kim
April 22, 2008 1:00 am

The White Knight disarmed.
=================

kim
April 22, 2008 1:09 am

You betcha there had already been a lot of cooling of the sidewalk from energy of evaporation.
=============================

Bob_L
April 22, 2008 5:45 am

Look at the temp of the galvanized post! If this is typical of most installations, a calm wind situation would have heat rising into the MMTS on any site not in the shade. That post would be warm for hours after sunset. Those posts should be white fiberglass.
What a mess!

SlyFoxDude
April 22, 2008 5:48 am

Do you think that Al Gore, when he was Vice President, knowingly had the sidewalks installed, resulting in higher recorded temperatures in order to bolster his “Global Warming” farce.
😉

Mike Bryant
April 22, 2008 6:21 am

Atmoz,
Sheesh,
Mike Bryant

Wondering Aloud
April 22, 2008 6:22 am

What I think… is that anyone who uses any of these grade 4 and 5 sites, and pretends they represent anything other than distortion and bias, is attempting to commit fraud.

April 22, 2008 6:43 am

Leave it to the scientists to form a consensus based on garbage. I’m sure more than one PoorHaplessDope reviews the data.

Bill in Vigo
April 22, 2008 7:30 am

I may be a bit confused here. I keep hearing (from some of the warmers) that just because the station has a CRN of 3,4,or 5 doesn’t really mean anything because the error would have been over a long term and wouldn’t effect the trend. I have some thoughts on this an may be confused.
1. If the average reading is elevated 3f degrees above a station with out micro-site bias and this happens at enough stations would that increase the average regional/global average? (3f is an arbitrary picked our of the air number)
2. If the average regional/global average is increased due to micro-site bias introduced in the last 40/50 years it would appear to make readings increase over that time frame.
3. If more and more sites are being upgraded with new equipment but also for convenience of operation micro-site bias is being unintentionally introduced to the sites would tend to make the regional/global average increase even more again due to micro-site bias.
My thoughts would be that the USHCN record has been compromised and I doubt that any algorithm would be able to completely remove all micro-site bias. With the introduction of more and more sites with micro-site bias that the trend would artificially be upward and would be man made due to the introduction of the bias.
Let me state that I agree that the climate has been warming for the last 100+ years. I do believe that we (humans) have caused a small part of that warming by producing heat to produce energy and using energy which produces more heat. I also believe that most of the warming is part of a cyclical rhythm that nature is in control of and that we will not be able to any time in the near future be able to change to any significant amount.
I do believe that elimination of pollution should be one of our priorities. Declaring a naturally produced gas (CO2) that is required to sustain life on this planet makes no sense to me. There are many more harmful pollutants that need to be controlled and that is where we should be putting our resources. I do believe in conservation and have changed many of my daily activities to conserve. I have changed over to mostly fluorescent lighting, I have reduced daily travel, I grow much of my food at home in the garden. I do believe that we need to develop alternate energy sources but not because of CO2 levels but for national security and economic reasons.
Perhaps I am confused but to me common sense is needed in this area and open not closed scientific study with no replication possible. Our controlling authority (NOAA) should enforce its own rules controlling the placement of weather stations. They should also insure that stations that have problems are either
A. repaired
B. relocated
C. removed from service if A and B can not be accomplished due to
urban encroachment or commercial site development.
We just need to get it right before we make a big mistake and cause more harm than the natural progression of climate would.
Just some thoughts from some one not a scientist.
Bill Derryberry

April 22, 2008 7:31 am

Bob_L, the metal post would not stay warm for hours after sunset. Metal’s effect is more short term. That is why it makes a poor insulator. — John M Reynolds

April 22, 2008 7:36 am

RE the comment by ATMOZ above, am I correct in concluding (he she) they don’t know the difference between surface temps of an object vs ambient air temps, and why the two may not be the same?

John B
April 22, 2008 7:51 am

I believe in the work as it’s been an eye opener for me. I agree with the concept that many of these sites are contaminated (badly) and that they may not be providing accurate results. I also agree that without visual evidence and exhaustive study how would someone be able to adjust a station back to where it should be (70% + of the US stations receive adjustments and who knows if they aren’t just adjusting the few good stations up to match the contaminated stations). Some of these stations have seen a great deal of change around them (Baltimore rooftop, U of A parking lot), but my question is about those that are contaminated that haven’t had a lot change around them.
I look at the CRN Rating Pie Chart and you can see the percentage of stations suffering from 1-5+ degree differentials, but is this differential a constant or is it a delta over the course of a century? In other words, a station like what we see above, is it 5 degrees off of average every year or is it a site that would suffer from a 5 degree temperature shift over a century? If it is the former, then it doesn’t matter as the delta over time would not change. I have had someone ask this in a conversation I had while explaining your project.
Thanks!

Harold Vance
April 22, 2008 7:53 am

The response by Atmoz immediately popped this question into my head: Where have all the skeptics gone?

steven mosher
April 22, 2008 8:06 am

Faced with the evidence of siting violations you have THREE options.
1. Ignore them, wave your arms, say the warming bias will be balanced by the cooling bias. This is Jones. This is Hansen.
2. Quantify them and adjust. In the same way Karl quantified the TOBS bias, the microsite bias could be evaluated. This is hard work fellows, but a person could get a PHD proposing an approach.
3. Eliminate the class5 from official datasets. Do this at the Quality control
level of data processing.
I prefer #3. I prefer it because #1 is pure bullshit and #2 will take time.
If your standard says, dont collect temps over concrete, then………DUHHHHH
dont collect temps over concrete.

Evan Jones
Editor
April 22, 2008 8:23 am

we can reasonably conclude that the microclimate issues with this station are small.
Yilmaz et alia (2008) would argue otherwise.
Jennifer Marohasy: I confess that have been a bit of a fan ever since that writeup in the Australian. I have tried to locate the negative feedback info from the AquaSat that you cite but I have come p sompletely empty. In fact the sites covering Aqua seem to avoid listing results entirely (a cynical individual might almost be led to wonder why this should be the case). I have seen many references to the negative feedback/homeostasis conclusions, but they all lead back to that same article–no independent confirmation whatever. So if you could put up any links that would help us here out in this regard, we’d be very happy! Keep up the good work (you have the support of at least one liberal).
What I think… is that anyone who uses any of these grade 4 and 5 sites, and pretends they represent anything other than distortion and bias, is attempting to commit fraud.
Think what you like. Who Decides? It is we, the laymen who decide. The expert witnesses merely inform; it is the laymen jurors who determine the policy verdict.
I will further observe that if the “experts” (supported by our taxes) had been doing their jobs properly in the first place, microsite issues would never have arisen, and if they had, they would be scrupulously adjusted for, and the adjustments would be well studied/calculated/confirmed, not merely “estimated”. Hint: “Yilmaz”–a name to remember.

Evan Jones
Editor
April 22, 2008 8:31 am

Note how weathered the concrete is.
However, the darkness of the concrete isn’t from weathering. It’s wet! That’s a cooling bias.
According to the Yilmaz measurements, tempertures 2 meters over concrete or asphalt are radically higher. This would confirm the the LeRoy “estimates”.

SteveSadlov
April 22, 2008 9:13 am

(Energizer Bunny)Hrumph, hrumph … a minor effect … washed out by the law of large numbers … hrumph, hrumph. (/Energizer Bunny)

William
April 22, 2008 9:14 am

ATMOZ tries to conclude that the sensor shield temperature is representative of the air temperature. The sensor shield is doing its job; it is not changing the temperature of the air flowing across it and onto the sensor inside. The concrete walkway, on the other hand is warming the air that is flowing across the sensor.
Anthony, I disagree with you that ATMOZ defense of the U of A site in the parking lot shows he believes siting is not important. Instead, it shows he is willing to go to great lengths to argue rhetorically to diminish the importance and relevance of your work on the surface stations project. It is consistent with his little April Fools joke that was intended to harass you by drawing you into a situation where his friends such as TCO would then extend you written abuse. It is also consistent with when he was masquerading about the internet as a climate scientist when in fact it turns out he is just a student. He is obviously polarized and has no credibility with me, which is why I no longer visit his blog.

Bill P
April 22, 2008 9:47 am

The pictures do speak volumes. I agree with the reader who notes the post temperature problem. Something needs to be addressed there. Has there been a gradual “creep” of these UHI / methods / materials problems, or was the system poorly-designed from the beginning? Regardless, it looks like it’ll be hard to do patchwork fixes after the visibility of your study.

Jerker Andersson
April 22, 2008 9:51 am

Interesting and very revealing infra red picture.
Now, how much does it actually raise temperature?
It would be intersting to actually have two temperature sensors for experimental use and then put one in similar conditions as above and the other over grass at a safe distance. When both show stable temperature the concrete piece is moved away and the sensors are read again to see what actual impact it has.
REPLY: I agree and I hope to accomplish such an experiment.

J. Peden
April 22, 2008 10:27 am

Have I finally gone over the edge in thinking that a site involving manicured, green grass can’t be very desireable either?

1 2 3 5