Reliability of Surface Temperature Records

Anthony Watt has produced a report based on his excellent work at document siting and installation issues at US surface temperature stations that might create errors and biases in the measurements.  The work is important, as these biases don’t tend to be random — they are much more likely to be upwards rather than downwards biases, so that they can’t be assumed to just average out.

We found stations located next to the exhaust fans of air conditioning units, surrounded by asphalt parking lots and roads, on blistering-hot rooftops, and near sidewalks and buildings that absorb and radiate heat. We found 68 stations located at wastewater treatment plants, where the process of waste digestion causes temperatures to be higher than in surrounding areas.

In fact, we found that 89 percent of the stations – nearly 9 of every 10 – fail to meet the National Weather Service’s own siting requirements that stations must be 30 meters (about 100 feet) or more away from an artificial heating or radiating/ reflecting heat source.

In other words, 9 of every 10 stations are likely reporting higher or rising temperatures because they are badly sited. It gets worse. We observed that changes in the technology of temperature stations over time also has caused them to report a false warming trend. We found major gaps in the data record that were filled in with data from nearby sites, a practice that propagates and compounds errors. We found that adjustments to the data by both NOAA and another government agency, NASA, cause recent temperatures to look even higher.

The conclusion is inescapable: The U.S. temperature record is unreliable. The errors in the record exceed by a wide margin the purported rise in temperature of 0.7º C (about 1.2º F) during the twentieth century. Consequently, this record should not be cited as evidence of any trend in temperature that may have occurred across the U.S. during the past century. Since the U.S. record is thought to be “the best in the world,” it follows that the global database is likely similarly compromised and unreliable.

I have performed about ten surveys for the effort, including three highlighted in the report (Gunnison, Wickenberg and the moderately famous Tucson site).  My son did two surveys, including one in the report (Miami) for a school science fair project.

23 thoughts on “Reliability of Surface Temperature Records”

  1. No scientist, committed to fair and honest science, would begin to tell the world what temperatures are without first insuring that his thermometers were accurate and sited properly. The fact that this was never done impeaches the credibility of the scientists involved.

    Of course, the fact that the IPCC embraced the Mann hockey stick without replicating or even auditing the work demonstrates an absence of good faith. They impeached their own credibility.

  2. Stan, the thermometers gave the right result, there was no need to question their accuracy.

  3. I’m not sure that the U.S. temerature record is the best place for skeptics to direct their energy. John V. did a study that pretty much concluded that the U.S. record is fairly accurate and Steve McIntyre seemed to acknowledge as much by then changing his focus to the “Rest of the World” (ROW) where I think it properly belongs. After all, the U.S. record now shows 1934 as being the warmest year on record. The alarmists then responded with “the U.S. is only 2% of the world”. Exactly. All the better to question the ROW record. There are definately some funky things going on with the U.S. data, but I don’t think they’ll add up to much. It’s far from our strongest argument. ROW? I think there’s a LOT wrong there (minimal rural records, Chinese data carefully preserved through the Cultural Revolution but now “lost”, the USSR break-up etc.).

  4. BillB,
    That is not the impression I have gotten from the Watts study at all.
    89% of the surface stations are out of compliance.

  5. Hunter,
    What BillB is saying is that while there is no doubt that 89% of the stations are out of compliance, the degree to which that noncompliance may have effected measurements may be small enough that it can be brushed off.

    What you’re missing is that while the unreliability of US Surface Stations may or may not be a devastating argument or the key to the issue, the fact that there are pictures involved is incredibly important. One of the reasons that so many people have believed Al is that he had pictures to back him up. The pictures may have been cherrypicked to tell his story and he may even have misrepresented some of the pictures, but damn it he had pictures, and people can identify with them. It’s a lot harder for someone who is not scientificaly inclined to identify with and truly believe a concept like negative feedback, especially if the scientific arguments are your opening/only argument.

    These pictures, this study, provide a way to get people thinking critically on a subject before you hit them with the math and science. The fact that the study is atempting to conduct a comprehensive survey is rather important, since it makes the point about a signifigant portion of the stations so a bad siting cannot be brushed off as an anomally.

    This study alone won’t transform national opinion overnight, but it can and will serve as a foot in the door for arguments. Just remember to use it. People find it much easier to ignore words than pictures.

  6. BillB, I’m sorry, but there is no way that with even a relatively minor error at each datapoint of just under 90% of your dataset that anyone should consider that dataset of high enough quality for anything more than a curiosity.

  7. 59% of the stations surveyed have siting errors of > 2 degrees C according to the USHCN’s own criteria. as this is more than 3 X the 100 year trend being measured, it seems astounding that in the face of so much uncertainty one could claim to have correctly accounted for all the error particularly as those maintaining the network have (by their own admission) not done any sort of specific site surveys and, in fact, tend to claim they are not necessary.

    while bill is correct that simply saying that the temperature record has some problems does not disprove AGW, i believe that it does provide an excellent example of the lack of rigor and weak methodology so often used to justify belief in AGW. clever (and likely manipulative and distortionary) statistical manipulation is not a valid substitute for good basic data. a researcher who fails to see this is just wanking.

  8. Okay. It is inconceivable to me that reasonable person would not admit that the surface temperature trend is biased upwards. But that is not the end of the story. The ocean temperatures should not have problems with asphalt, trash burners, building exhaust . . . . It is interesting that according to satellite measurements, the temperatures over the oceans are no higher now than they were in 1980. (Although, applying least squares, you will still get a positive trend of 0.11 degree per decade due to higher temperatures in the last half of the record. Those temperatures may be due to the positive phases of ocean oscillations.) If you feel that is the end of the story – not quite, GW pessimists conjecture that AGW would show up more over land than over the ocean. So looking at the satellite record for land, we see a positive trend of 0.17, and temperatures are a bit higher now than 1980. I have submitted the following question in various forums and have not had any response: when satellites measure near-surface temperatures, might they be picking up UHI? And it would not surprise me if they are picking up trends due to land use changes. Oh, and for the record, since urbanizing areas constitute such a small portion of the earth’s surface, GW alarmists dismiss the impact of UHI on the overall GMT – urban areas are a fraction of the land surface, and land surface is a fraction of the world’s s surface. One chink in the GW alarmist’s position is that the problems with surface temperatures are far more than UHI – local bias affects not only Albuquerque, but also the rural stations in Alaska.

    John V did take an extremely small sample size (not a statistically valid #) of higher quality stations and showed that their trend is very similar to the adjusted trend of all US stations in the GISS methodology. There are many issues with John V’s work, and I will not repeat them here. Steve McIntyre and Anthony Watts (at least initially) have been very polite and apparently appreciative of John V’s work, but lately Watts frequently shows irritation at some of John V’s comments.

  9. “the temperatures over the oceans are no higher now than they were in 1980. (Although, applying least squares, you will still get a positive trend of 0.11 degree per decade due to higher temperatures in the last half of the record”

    That is truly one of the most retarded statements I’ve ever seen.

  10. Stevo,

    translation for dummies of AnInquirer:

    temperatures over oceans went up from about 1980 till the early 2000’s and are now back down to the 1980 level leaving an overall positive trend for the period.

  11. It seems that civilization has had a impact in more ways than just an increase in CO2. Agriculture has affected the reliability of lake sediment proxies. I’m betting civilization has affected tree ring proxies. Atomic bomb tests have affected the usefulness of C14 studies.

    On the tree ring issue. I am wondering if higher altitude trees get a bigger % growth spurt out of just about any positive growth factor. Trees living at lower elevations get plenty of sunlight, fertilizer, warmth, and rain. Extra fertilizer via NOX or enhanced sunlight due to aerosols or more carbon dioxide for the lower altitude trees might not make a big difference in growth rates. But for the resource-starved higher altitude trees, these factors could make a bigger difference. I know one of the more polite AWG proponents claimed there were multiple lines of evidence that the sun does not drive the temperature changes we’ve seen in the last 100 years or so, but a lot of that result depends on proxies and these guys tend to judge the proxies via computer models. The entire process gives me an uneasy feeling, although I do admit there is a lot about it I don’t know.

  12. Jim,
    If you want to read what thoughtful scientist says about the multiple lines of climate forcings that humans make, read Dr. Pielke, Sr’s. blog.

  13. Kuhnkat, thank you for your attempt to increase understanding of statistics. I am reminded of a past discussion with a GW pessimist in which I opined that for chronological GMT series a polynomial fit might be better than OLS for a linear fit. I thought I had a great analogy. If in mid-1944 you did a linear fit of German vs. Russian military success, you would give the future to Germany. However, if you did a polynomial fit, you would get a better handle on the future. His response was that “we are talking about temperature, not about armies whose fortunes can rise or fall on a single battle. Ah, it is better sometime to go to bed rather than to straighten out everybody on the internet who is “wrong.” 🙂

  14. I’m not upset that humans are changing the planet. We are, after all, just as natural as the blue-green algae that began spewing toxic oxygen into the atmosphere a few billion years ago. If we are going to change it in such a way that kills us off, I would be concerned, but otherwise – change is the way of the universe.

  15. Did any one watchthe TV program titled (I think) “raising the baby mamoth”. Any way, the baby was located in ice now but when it was burried there wasn’t permafrost there. The location is in northern Siberia and the baby was dated at 40,00 years old. The baby was to well preserved to have been uncovered by thawing as a result of warming. She was only just starting to become uncovered by surface errosion and most of her was still in ice. My point is that 40,000 years ago a baby mamoth was in a location that is currently Arctic snow and ice where it is possible for only the hardiest of winter animals can survive. It doesn’t look like we will have the conditions at that location that a baby anything will survive unless global warming actually does ake place (which I think is only temporary). I would love to be able to go outside here in the 4 corners area of the US in short pants and tee shirt in February so until then I won’t worry about gloabal warming to much.

  16. This whole JohnV thing is a lie. JohnV used 17 stations with poor geographical distribution and without complete adjustments (agricultural and box construction bias, for example). Many of the stations were closed or had recent equipment changes. Very few actually met the criteria for the entire time period. When he could not get enough category 1 and 2 stations that were not located in Urban areas he started using flawed stations (3’s).

  17. MikeC:
    I think you are unduly harsh with JohnV’s work. It is widely recognized that he did not have a statistically significant sample size to make any valid claims; however, he is recognized as honest, and he did make his data & work publicly available. That later move is quite rare in the AGW camp — of course, it was not his data; it was the data that Anthony Watts had made available. There have been some criticism of John V’s work, and certainly when he used CRN 3 stations, that undermines his point that GISS adjusted trends follow high quality stations. Nevertheless, I do not see how you can call it a lie. Yes, there was poor geographical distribution, but I do not understand your complaints missing adjustments, closures & recent equipment changes. If I understand you correctly, CRN 1 & 2 should not have these issues.

  18. Has anyone surveyed, say, 50 stations where there is heat bias vs 50 stations relatively close, but not within the heat biased area? Also, distributed across the US so as to be somewhat representative?

  19. Jim, I am not aware of any study that you describe. Indeed, it might be tough in the USHCN network to get 50 quality stations outside of “heat biased” areas. One work by David Archibald may interest you — his March 2008 paper that studies the average of four rural stations since 1893. If you add to his study other stations that I know are out of UHI, you would get the same result. Reference: and select the March 2008 paper. Of course, some could argue that his graph is an illustration of what you can do by cherry-picking. However, I do not think you can dismiss his work that easily. Look for stations on the various continents that are not affected by UHI or local site issues, and my examination of them shows the same trend. Lest anybody gets excited that we have clarity on the issue of long range temperature trends — we don’t. Satellite data agree that there has been a positive trend from 1979 to the early 2000s. Of course, that was during positive phases of PDO and AMO, so reasonable people can disagree.

  20. An Inq. – IMHO, the stations that are affected by UHI should just be discarded as tainted. I believe the raw data is available. It would be interesting to create a grid over the US, find the rural stations within each grid, check each rural station for anomalies, throw out anomalous readings (not the entire station), get the monthly average temps of the rural stations within the grid, then average them all together to get a monthly chart. Hopefully, there would be enough rural stations to uniformly cover the country. I guess if there were not, one could make the grids bigger, to a point.

  21. Jim, the problem is not just with UHI. The problem is also with micrositing issues such as locating the station next to exhaust from air conditioning units — and air conditioning was not there 60 years ago. In many places, the thermometers have been moved closer to buildings. Even if the buildings are in rural areas, they still give off heat. Many great examples, but I needed to laugh at one example in rural Alaska — next to the electric coop with plenty of heat being given off.
    What Anthony Watts has done is try to find quality stations that have minimal local siting issues.
    Perhaps very few people realize that the raw, unadjusted data shows that U.S. temperatures are no higher now than they were in the 1930s. However, the official keepers of the record feel that we need to make adjustments for Time of Observation and other issues. The methodology of collecting data has changed, and so programs have been developed to make adjustments for this. The TOBS adjustment process is not without controversy, but the graphs produce do have those adjustments.
    For these and other reasons, the satellite data offers an attractive alternative. However, this data goes back only 30 years; a period over which we have been in positive phases of PDO and AMO, and we would expect an upward trend. One issue that is completely ignored by GW pessimists is that satellite temperatures over oceans (no UHI) is no higher now that it was 30 years ago.

  22. An Inq: Thanks for the clarification. I was aware that different equipment is used at various sites and also of the time of day problem. The fact that time of day of the measurement is critical is obvious and some kind of correction must be made. I am with you on the satellite data, they are the best, truly global temperature measurements we have. I am disturbed at attempts to stretch sparse measurements over the globe to read the T trend, as well as things like Steig’s analysis of the Antarctic temperature trend. It appears to me that sometimes you just have to accept the fact that there isn’t enough data to draw a global or continent wide conclusion and live with it. I am also disturbed when researchers make up new statistical techniques that have not been vetted by the wider scientific and mathematical community. I am more of a doubter than denier. But one thing’s for sure – the debate is not over.

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