What a great USHCN station looks like: Tucumcari

I’ve spent a lot of time on this blog showing how badly maintained and situated the stations in the USHCN network are. And rightly so, the majority of them have issues. But, finding the good ones is actually more important, because they are the ones that hold the true unpolluted temperature signal. Unfortunately, the “good ones” are few and far between.

But when one comes along that is a real gem, it deserves to be highlighted. I present the USHCN climate station of record for Tucumcari New Mexico, COOP ID # 299156, located at the Agricultural Experiment station about 3 miles outside of the edge of town.

I “had” (he just moved to St. Louis) a nephew who lived in Tucumcari, and he just happened to be friends with the director of the experiment farm. Before my nephew left they both helped me get this survey done.

Click picture for additional images

Surfacestations.org image gallery link

This station has several advantages:

  • Length of continuous record – going back to at least 1946 at this location, possibly to 1905 but NCDC MMS metadata stops at 1946.
  • Length of continuous instrumentation – using mercury max/min thermometers
  • Length of continuous data record – there doesn’t appear to be any missing years
  • Lack of encroachment – 3 miles from the northeast edge of town, little development, little UHI. Tucumcari is well off the beaten path of development. Population actually declined 12% in recent years.
  • Good siting – the station rates a CRN2 due to distant trees and sun angle, and one small asphalt road 70 meters away.

See the station survey report here (PDF) You can also make out the station on Google Earth using this link. After opening Google Earth, zoom in and the fenced outline and screen will be visible.

Eyeballing, you can see that the temperature data trend for Tucumcari is slightly positive over the last century, about 0.5°C, but there is a “bump” in 2000, which brings it to about 0.9°C. This same bump appears in neighboring stations such as in San Jon (33km away) and in Boys Ranch (135km away). There is nothing in the metadata location or equipment record to suggest a reason for the bump. So, either the bump is naturally occurring, or there is something we don’t know about that changed in the local environment, or we have another data set splicing error like the GISS Y2K debacle from last year.

Click for larger graph from NASA GISTEMP

I plotted the data provided by GISS (which you can find here) to show the effect of the “bump” at year 2000 on the overall trend:

Click for larger graph

Here is the data plot after the GISS homogeneity adjustment, I’ve hue shifted my saved version to red to help keep the graphs visually separate:

Click for larger graph from NASA GISTEMP

And here is the overlay of the USHCN data from GISTEMP and the data from the GISTEMP homogenization process:

In this case, the GISTEMP homogenization code appears to do what would be reasonably expected; reduce temperatures in the present to account for population growth and UHI. I’ve pointed out more than a few times that the GISTEMP homogenization adjustment often becomes flawed for truly rural sites like this when there are large cities within the 250km up to 1200km (depending on process) adjustment zone that Hansen uses, that have accelerating UHI trends. Due to these cities, often the past of a rural station gets adjusted cooler, resulting in an increased temperature trend, such as what happens at Cedarville, CA. Hopefully we’ll have a detailed analysis of that adjustment from John Goetz soon.

If you look at this list, you’ll see that there are a lot of rural stations within 250km. Tucumcari has the advantage of being truly in the middle of nowhere when it comes to other big cities. The closest big cities are Amarillo and Lubbock, but as I understand the algorithm used, when they are near the edge of the 250 km zone, their weighted value decreases.

In this case though, the GISTEMP homogeneity adjustment doesn’t take Tucumcari’s declining population into account, it only uses nightlights, and while the population may dwindle, town infrastructure usually doesn’t; streetlights counted around the station likely remain.

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June 29, 2008 5:10 pm

Well at least the adjustments brought the recent temperatures down this time.

June 29, 2008 6:15 pm

Could you run trend-lines to see the impact of the homogenization process? By looking at it, it seems to have turned a warming trend into a cooling one!
REPLY: Sorry, I don’t take requests from “spam”

June 29, 2008 6:21 pm

Just by eyeball, but it doesn’t look like the homogenized GISS was adjusted downward. If you check the original graph, the 2000 figure looks like it’s halfway between 16.0 and 16.5. But in the homogenized graph, the 2000 figure is almost at 16.5. In the original graph, the “peak” in the 1950s is just past 15.5, but in the homogenized graph it’s close to 16.5. Also, the “peak” in the 1930s doesn’t reach 16.5 in the original, but is halfway between 17.0 and 17.5 in the homogenized graph.
REPLY: The absolutes change, but not identically over the time series. Hence the overlay to see where the magnitude of adjusment differs. Look again. We are after trends, not absolutes.

Bill Newberry
June 29, 2008 6:45 pm

I’m getting somewhat confused on these “changes.” The GISTEMP data adjusted Farmington and Orono Maine to look like the 30’s and 40’s were much cooler than what was actually documented which in turn makes the past decade look significantly warmer than it really was. When I looked 10 years ago, Farmington was showing a cooling trend. This has been reversed with GISTEMP figures and now this humongous metropolis in central Maine is showing warming. Is that what the Tucumcari adjustments are about???

June 29, 2008 7:14 pm

[…] wattsupwiththat.wordpress.com Tags: temperature Related Posts […]

June 29, 2008 7:31 pm

It’s what you can’t see that may well be affecting the temperature at this site. There is extensive irrigation in the area and hence increases in humidity. And as we all know water vapour is the most potent GHG of all.
The periods in which the irrigation scheme was implemented seem to correspond with upward trends in temperature (1944 to 1950 and up to 1976). Interestingly, temps don’t then plateau after these periods, when presumably the extent of irrigation stays about the same, but decline back down, which indicates the overall trend is cooling. And the cooling is being masked by periods when irrigation increases.
I’d be interested to see volume of water from the Tucumcari Project used for irrigation overlayed on the temperature history.

Eric Gamberg
June 29, 2008 7:41 pm

Here’s a quick plot using the raw data from the site without any NOAA or GISS adjustments.
Looks like a negative slope including the most recent data. It’d be interesting to do a comparison of monthly data from the WCDC to the GISS raw and adjusted similar to this:

June 29, 2008 8:08 pm

A point to bear in mind about irrigation. Most studies show a modest cooling effect over the the area irrigated, which is what you would expect from evaporation and transpiration. However, this cooling is counteracted by increased humidity causing GH warming. Generally, the humidity will move away from the irrigated area into ajacent non-irrigated areas where there is no evaporative cooling and just the GH warming from increased water vapour.
Therefore areas around irrigated farmland will show warming. I don’t know of any studies that try to measure this effect, but regional analyses show an overall warming effect from irrigation. Which indicates to me that the wider warming effect effect from irrigation is substantially larger than the local cooling effect.

James S
June 29, 2008 8:19 pm

The question is why is a good rural site being adjusted at all? Surely this is one of those sites which don’t need adjusting?

Mike Bryant
June 29, 2008 8:23 pm

Great News!!! According to Lucia’s latest efforts, the temperatures are following Hansen’s “C” scenario most closely! This means that the temperatures are responding as if the Earth’s CO2 levels have been drastically reduced. ( Even though they have not been reduced. )

June 29, 2008 11:47 pm

REPLY: Sorry, I don’t take requests from “spam”
Is that because its a pseudonym? Unfortunately, after a border-line stalking incident (related to my work), I found a need to adopt one. But if that’s your policy….

June 30, 2008 12:17 am

I believe Anthony meant it as a tongue in cheek joke on your username, however, if he was interested in doing as you ask, he probably would have responded positively.
I can assure you, the man is overworked and is picking his tasks carefully.

June 30, 2008 4:09 am

Anthony, I guess I was confused because the plot points in your overlay don’t match the actual values in the individual graph for the homogenized GISS. So if you’re looking at the trend, the homogenized data was adjusted upward by almost 1°C for the period up to the 1930s, then by smaller increments from the late 1930s onward, making for a much flatter trend.
But as James S points out, why the adjustment in the first place, when the site and the data record is good? And why should the GISTEMP homogenization code adjust the pre-1940s readings upward? If the purpose is to reduce temperatures in the *present* to account for population growth and UHI, shouldn’t the historical readings have remained unchanged?
REPLY: Bingo. This site should not have been adjusted at all.

June 30, 2008 6:15 am

Perhaps I’m missing something, but it appears to me that the temperature trend starting at the peak around 1934 and going to 2000 is on a downward slope.
And I agree with James S who wrote: “The question is why is a good rural site being adjusted at all? Surely this is one of those sites which don’t need adjusting?”
Jack Koenig, Editor
The Mysterious Climate Project

June 30, 2008 6:21 am

Anthony wrote: “REPLY: Sorry, I don’t take requests from “spam” ”
It is one of those names a moderator has to be wary of! HOWEVER, as a network consultant, I routinly name wireless access points with identification such as “Virus Generator,” “Spam Generator,” “Address Harvester,” and the like to ward off potential hackers (in addition to the highest password security each particular system will accept).
But on a blog? Bad pick!
Jack Koenig, Editor
The Mysterious Climate Project

steven mosher
June 30, 2008 6:31 am

James S. this site is adjusted by NASA for the following reason.
1. in 1995 a picture was taken from space. Not from a guy on on the ground, a picture was taken from space.
2.that picture showed that there were lights turned on at night around this site
3. Hansen concluded from this picture that the site was NOT RURAL.
4. Hansen then adjusts sites that he thinks are not Rural, based on a photo
from space.
Then Anthony and team go out and take pictures of sites. at ground level.
Then Hansen fans say, hey Anthony your pictures prove nothing.
Well here they prove one thing. NIGHTLIGHTS is a flawed methodology.
It doesn’t get any simpler than that. Nightlights is supposed to identify non rural sites. You would think that a NASA scientist would do a cross check.
Maybe we should mail him some O rings.

Dan Evens
June 30, 2008 6:59 am

It looks like there’s something wrong with the graph showing both raw and homog. Is it possible the homog is shifted down by about 1 degree?

David Segesta
June 30, 2008 8:02 am

Off topic
Anthony. I don’t mean to burden you any further, but I’m wondering if you ever did the experiment to measure the temperature of tree leaves to see if they maintain a temperature different than the surrounding air.
REPLY: Not yet, we have so much smoke in the air here that I’m concerned it will affect the measurement. Waiting.

Bill P
June 30, 2008 9:09 am

RE: “Hansen concluded from this (satellite) picture that the site was NOT RURAL. 4. Hansen then adjusts sites that he thinks are not Rural, based on a photo from space.”
1. Was this adjustment known to take place in 1995?
2. Hansen would retroactively adjust for a supposed urban site by lowering (?) the temp, using a certain formula?
3. From the comments above on humiditity and temperature, it seems the interrelationship of irrigation / surface moisture / temp are numerous, overlapping and conflicting.
4. With the uncertainties created by Hansen’s manipulations and the unknown agricultural history, aren’t there still some questions about this site? A “gem” still in the rough?

Bill in Vigo
June 30, 2008 11:54 am

Sort of tongue in cheek, I have long suggested that we turn off about 1/2 the street lights in the world and see what that would do to the temp in a year. I wonder just how much heat say 500,000,000 500W street lamps would produce and how much heat it would use to produce the energy to light the lamps? If Hansen uses them to determine rural and urban it might make a difference. I wonder how much of a close up picture they use for the determination. Just food for thought.
Bill Derryberry

Evan Jones
June 30, 2008 2:20 pm

I notice temps have gone up 1.5ºC or so since 1980. That’s around four times the national average–according to GISS results. NOAA shows a lesser increase ( c. 1ºC ).

Evan Jones
June 30, 2008 2:24 pm

Well here they prove one thing. NIGHTLIGHTS is a flawed methodology.
As he rolled down the tarmac we heard him to shout,
“Happy Earth Day to all, Lights 0, and OUT!”

Leon Brozyna
June 30, 2008 3:50 pm

This post, as well as the preceding post on SIM/barycentric ideas, are illustrative of why this is my favorite place to read daily. It has the open approach I expect when matters of science are being discussed. Even the comments are {for the most part} quite civil, even when differing viewpoints are being discussed. Plus it’s no where near as depressing as reading the daily listings at JunkScience with all the lunacy that passes for science is revealed. Or all the coding issues covered at Climate Audit.
You could have buried this particular station in the surfacestation database, if you were agenda driven. But in the true spirit of science and understanding the real world, you post this as an example of what’s being done right. And when that bump around 2000 is noted, there’s none of “the science is settled and this proves it,” or “it’s data manipulation”.
Or in the previous article on the SIM hypothesis. You post it while expressing your reservations. Now, while I like the ideas in this hypothesis {it does have a certain aesthetic appeal}, it raises as many questions as it tries to answer. Even here the comments cover quite a range of positions regarding this hypothesis, yet are discussed in a manner that does great credit to you.
Kudos to you and keep up the great work.

June 30, 2008 4:16 pm

Heads up, CA is refusing connections again.

steven mosher
June 30, 2008 6:20 pm

bill P
1. Was this adjustment known to take place in 1995?
No the satillite photos were taken in 1995. Those photos capture lights at night. Hansen uses those photos to say ” bright equal urban” “dark equal rural” grunt grunt.
2. Hansen would retroactively adjust for a supposed urban site by lowering (?) the temp, using a certain formula?
Dont get me started. read CA on hansens magical mushroom adjustment dance.
3. From the comments above on humiditity and temperature, it seems the interrelationship of irrigation / surface moisture / temp are numerous, overlapping and conflicting.
Shrugs. i do code not watering.
4. With the uncertainties created by Hansen’s manipulations and the unknown agricultural history, aren’t there still some questions about this site? A “gem” still in the rough?
The point is THIS. hansen’s adjsutment methodolofy takes a perfectly good site and adjusts it. I could care less whether it is up or down. This site is rural. It it well sited. It has a long record. DONT EFF WITH GOOD DATA.
rant off.

June 30, 2008 6:53 pm

Anthony, you say over at CA that you will look into irrigation changes as a possible cause of the warming in the 1990s.
Given Christy’s study (linked above), which finds a regional warming effect from irrigation, the total volume of water used in irrigation from the Tucumcari Project would be an interesting comparison to the temperature record.
All I could find online is 10 years data of total irrigated land in acres, which ends in 1992. Full records doubtless exist somewhere. Also I think volume of water used in irrigation is a better metric than area irrigated because volume will determine the amount of water vapour introduced into the atmosphere. The 2 may be closely related. However, one description of the scheme says,
“Irrigated pastures fill a niche in this area because of their ability to produce under varying levels of irrigation,” said Rex Kirksey, superintendent of NMSU’s Agricultural Science Center in Tucumcari. “Pastures remain a viable option in many situations where irrigation water is too limited or unpredictable for corn or alfalfa production.”
Which makes me think there isn’t a good relationship between area irrigated and water volume.
And at the risk of belabouring the point, the significance of Tucumcari may be that it shows the effect of irrigation without any other significant local effect. For those of you who didn’t read the Christy paper, he found, in a region remote from irrigation, temperatures declined over the 20th century.
BTW, what clued me into the irrigation effect is that here in Perth Western Australia a typical sunny day in summer is 35C to 38C. However, we get a few days each year when we go into the 40s. I think 44C was the hottest day this year. These hot days are invariably humid, although without cloud, and nights are much hotter than normal in summer; +10C or more on some nights. I realized the 40C+ days occur after rain in the interior and the normally dry winds from the interior become relatively humid.
Its hot because the air is humid and the sky is clear. The extra heat results from a near ground greenhouse effect from the extra water vapour.
REPLY: I just completed my basic research, posted on the main page, and like you could not find the overall water volume numbers for the entire project, only a portion. But I did find something else. Leakage. The irrigation canal system that serves the area near the USHCN station loses HALF of the water to the surrounding area, and it is getting worse.

Jeff Alberts
June 30, 2008 7:37 pm

Mosher, of course you mean you “couldn’t care less…” Totally opposite meaning from “could care less”.

June 30, 2008 8:38 pm

[…] Sunday I posted about the USHCN climate station of record in Tucumcari, NM highlighting its positive points since it has all the hallmarks of a well sited station with a long […]

Bill P
June 30, 2008 10:14 pm

Anthony, I don’t know if you’ve addressed this already here or on Surface Stations, but seems germane to all the rural monitoring sites.
It’s interesting to me that NOAA acknowledges the importance of avoiding agriculturally developed sites in their licensing agreement handbook:
“Licensor and Licensee recognize the importance of maintaining Site integrity for among other things, to… minimize potential impacts from long-term land use and land cover changes on the climate record at the USCRN Site, such as irrigation and tilling of the land near the site, typically within 100 meters.” —From U. S. Climate Reference Network Site Information Handbook, Pg. 17.
But cultivation and irrigation, considered “natural” land uses, might tend to creep past these 100-meter barriers over time, and if Christy’s essay is right, these land uses affect temperature readings more than I realized.
Thanks for your ongoing investigation (I read on to part two of this).

June 30, 2008 11:08 pm

I’m willing to bet irrigation affects temperatures kilometers away from the source.

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