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Temperature Adjustments At USCRN1 Stations

March 16, 2015

By Paul Homewood


Guest Post by Ron Clutz



Adjustments Multiply Warming at US CRN1 Stations



A study of US CRN1 stations, top-rated for their siting quality, shows that GHCN adjusted data produces warming trends several times larger than unadjusted data.


The unadjusted files from ghcn.v3.qcu have been scrutinized for outlier values, and for step changes indicative of non-climatic biases. In no case was the normal variability pattern interrupted by step changes. Coverages were strong, the typical history exceeding 95%, and some achieved 100%.(Measured by the % of months with a reported Tavg value out of the total months in the station’s lifetime.)


The adjusted files are another story. Typically, years of data are deleted, often several years in a row. Entire rows are erased including the year identifier, so finding the missing years is a tedious manual process looking for gaps in the sequence of years. All stations except one lost years of data through adjustments, often in recent years. At one station, four years of data from 2007 to 2010 were deleted; in another case, 5 years of data from 2002 to 2006 went missing. Strikingly, 9 stations that show no 2014 data in the adjusted file have fully reported 2014 in the unadjusted file.


It is instructive to see the effect of adjustments upon individual stations.



A prime example is 350412 Baker City, Oregon.


Over 125 years GHCN v.3 unadjusted shows a trend of -0.0051 C/century. The adjusted data shows +1.48C/century. How does the difference arise? The coverage is about the same, though 7 years of data are dropped in the adjusted file. However, the values are systematically lowered in the adjusted version: Average annual temperature is +6C +/-2C for the adjusted file; +9.4C +/-1.7C unadjusted.


How then is a warming trend produced? In the distant past, prior to 1911, adjusted temperatures decade by decade are cooler by more than -2C each month. That adjustment changes to -1.8C 1912-1935, then changes to -2.2 for 1936 to 1943. The rate ranges from -1.2 to -1.5C 1944-1988, then changes to -1C. From 2002 onward, adjusted and unadjusted values are the same.


Some apologists for the adjustments have stated that cooling is done as much as warming. Here it is demonstrated that by cooling selectively in the past, a warming trend can be created, even though the adjusted record ends up cooler on average over the 20th Century.


A different kind of example is provided by 417945 San Antonio, Texas. Here the unadjusted record had a complete 100% coverage, and the adjustments deleted 262 months of data, reducing the coverage to 83%. In addition, the past was cooled, adjustments ranging from -1.2C per month in 1885 gradually coming to -0.2C by 1970. These cooling adjustments were minor, only reducing the average annual temperature by 0.16C. Due to deleted years of data, San Antonio went from an unadjusted trend of +0.30C/century to an adjusted trend of +0.92C/century, tripling the warming at that location.


The overall comparison for the set of CRN1 stations:





1874 to 2014






Average Trend




Std. Deviation




Max Trend




Min Trend




Ave. Length




These stations are sited away from urban heat sources, and the unadjusted records reveal a diversity of local climates, as shown by the deviation and contrasting Max and Min results. Six stations showed negative trends over their lifetimes.


Adjusted data reduces the diversity and shifts the results toward warming. The average trend is 4 times warmer, only 2 stations show any cooling, and at smaller rates. Many stations had warming rates increased by multiples from the unadjusted rates. Whereas 4 months had negative trends in the unadjusted dataset, no months show cooling after adjustments.


Periodic Rates from US CRN1 Stations





























Looking at periodic trends within the series, it is clear that adjustments at these stations increased the trend over the last 100 years from flat to +0.68 C/Century. This was achieved by reducing the cooling mid-century and accelerating the warming prior to 1998. provides a list of 23 stations that have the CRN#1 Rating for the quality of the sites. I obtained the records from the latest GHCNv3 monthly qcu report, did my own data quality review and built a Temperature Trend Analysis workbook. I made a companion workbook using the CHCNv3 qca report. Both datasets are available here: 


As it happens, the stations are spread out across the continental US (CONUS): NW: Oregon, North Dakota, Montana; SW: California, Nevada, Colorado, Texas; MW: Indiana, Missouri, Arkansas, Louisiana; NE: New York, Rhode Island, Pennsylvania; SE: Georgia, Alabama, Mississippi, Florida.


In conclusion, it is not only a matter of concern that individual station histories are altered by adjustments. But also the adjusted dataset is the one used as input into programs computing global anomalies and averages. This much diminished dataset does not inspire confidence in the temperature reconstruction products built upon it.


The excel workbooks with data and analyses are provided for your interest and review.





PH Comments


What is particularly interesting is the example of Baker City. According to the USHCN data, there has been no ore than 0.1C adjustment for TOBS, the excuse usually wheeled out to explain cooling of the past.

This tallies with the station metadata, which confirms that there has only been a minor change in observation times, from 22.00 to 24.00, a change made in 1999.

As the location has not changed since at least 1930, on the face of it, there is no reason at all for any adjustments to be made.

  1. Rud Istvan permalink
    March 16, 2015 6:42 pm

    I did a similar analysis for a draft guest post submitted last month to Judith Curry. In the surface stations project there are 14 CRN1 stations. 4 urban, 3 suburban, 7 rural. The 4 urban might still have signifiant UHI. Of the remaining 10, none showed meaningful warming in the raw. 9 of 10 did in the homogenized, including Baker City of this post. Laramie WY also had the present warmed. Only Apalachicola FL escaped unscathed with raw and homogenized similar.

    • Brad permalink
      March 17, 2015 4:25 am

      So how do we get this corruption exposed by the MSM???
      Can someone start running full-page ads in papers with an ethical editorial board?

      What if everyone who was fed up with our goats( govts, love that predictive spelling) simply quit paying taxes?

      • Windchaser6 permalink
        March 21, 2015 6:17 am

        The problem is that no matter what facts you show people, if those facts contradict what they feel is the truth, they will dismiss said facts as unimportant, and continue on with their rhetoric. Conversely, if they find facts that support their ideals and beliefs, they will wave them around and scream about how right they are…

        I have never thought that global warming was an issue. I know there is climate change, has been since the beginning of time, regardless of what man does on this planet, the idea that we could impact the environment so dramatically over the past 150 years, is just idiocy to me.

  2. Newsel permalink
    March 16, 2015 7:17 pm

    Another case of “homogenized” data that paints the picture the warmers wish to portray.

    More Scientific fraud and a case of the end justifies the means? The more one digs the deeper the cesspit.

  3. March 16, 2015 7:30 pm

    Great work Paul! Too busy right now to look at your work in any kind of detail; but am looking forward to it when I can break free. (darned day job!)

    • A C Osborn permalink
      March 16, 2015 7:46 pm

      Actually the work is by Ron Clutz.

      • March 16, 2015 10:05 pm

        Sorry about that Ron! Too much of a hurry on my part.

  4. March 16, 2015 11:23 pm

    Reblogged this on Tallbloke's Talkshop and commented:
    More ‘Adustments’ to temperature data that look unustified.

  5. Anto permalink
    March 17, 2015 2:52 am

    That’s what happens when you leave the arsonists in charge of the fireworks factory.

  6. March 17, 2015 5:45 am

    fantastic detective work! keep it coming. maybe one day we’ll adjust the stockmarket too so that a down day will be homogenized to an up day! free money for all! 🙂 hahahaha

  7. Boyfromtottenham permalink
    March 17, 2015 6:23 am

    Hi from Oz. how the hell do they get away with this? It clearly isn’t accidental, so it’s systematic manipulation of key scientific data. Are these people above the law?

  8. Arthur Ellingsen permalink
    March 17, 2015 11:06 am


  9. Arthur Ellingsen permalink
    March 17, 2015 1:36 pm

    Manipulating data is wrong. They should be brought to court and put in jail!

  10. March 17, 2015 5:46 pm

    Anyone interested in the Excel workbooks supporting this report can access them at blog.

  11. March 18, 2015 9:36 am

    I liked the comment about a homogenised stock market; isn’t that what the ongoing banking crisis was. Another case of a pseudo scientific model being manipulated by people who had public trust.

  12. DD More permalink
    March 18, 2015 11:00 pm

    So these adjustments are only made in a few stations and only show up at every station you look at? Coincidence or should you be running a lotter prediction service at the rate you find stations with errors.

    • March 19, 2015 12:54 pm

      Not sure of your point. The stations were chosen solely because of their CRN#1 rating. A year ago I looked at the unadjusted trends. This year I updated to include 2014 values and decided to compare to adjusted data. 22 of 23 records were altered by adjustments, and the net result was warming of the average station.

      Maybe you are suggesting I should look at station by station results.

  13. March 19, 2015 1:27 pm

    DD More, here’s additional info.

    In response to a comment, this post shows the effect of adjustments on each of the 23 stations. The average station was warmed by +0.58 C/Century, from +.18 to +.76, comparing adjusted to unadjusted records.

    19 station records were warmed, 6 of them by more than +1 C/century. 4 stations were cooled, most of the total cooing coming at one station, Tallahassee.

    So for this set of stations, the chance of adjustments producing warming is 19/22 or 86%.

    Details here:

  14. March 19, 2015 1:35 pm

    Correction: 19/23 or 83%

  15. March 23, 2015 2:52 pm

    Reblogged this on Globalcooler's Weblog.


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