Another quiet GISS update

Yesterday I surfed to the Datasets and Images page on GISS, something I ordinarily do only around the fifth of each month as I wait for the latest monthly temperature updates from GISS. The information on that page rarely changes, so I was surprised to see the following addition:

June 9, 2008: Effective June 9, 2008, our analysis moved from a 15-year-old machine (soon to be decommissioned) to a newer machine; this will affect some results, though insignificantly. Some sorting routines were modified to minimize such machine dependence in the future. In addition, a typo was discovered and corrected in the program that dealt with a potential discontinuity in the Lihue station record. Finally, some errors were noticed on (set of stations not included in Met READER) that were not present before 8/2007. We replaced those outliers with the originally reported values. Those two changes had about the same impact on the results than switching machines (in each case the 1880-2007 change was affected by 0.002°C).

Now, the thing that caught my eye was the “June 9, 2008″ in bold. Perhaps I am reading more into the use of a specific date and boldface type than I should, but I interpret it to mean the website entry was made on June 9. However, I am 99% certain that entry was not on the GISS website on July 5, which is the date I started looking for the July update (after that date I just did a reload of the tab holding the GLB.Ts+dSST.txt file, so I would not have seen updates to the parent page after July 5). I say 99% because I am almost certain I would notice the additional entry as I scrolled down to the GLB.Ts+dSST.txt link, but I cannot say I am 100% certain. We will need to wait a number of months before the internet archives updates the history for that page.

[Update] I found a cached version of dated June 20 off of Live search. This page is linked directly from and further explains the June 9 update. Thus, I would conclude that the update was made at least as early as June 20. The remaining search engines all have this page and the parent page cached on July 11 or later. [End Update]

Why is this important? For those of you who followed the GISS Step 2 thread on this site, you will recall that on June 19 Steve and I were commenting on a mysterious seventh version of the Chatham Island record. I noticed that the seventh version came from a UK site: (these days, Google will find almost anything). Furthermore I noted:

Here is where it gets interesting. Looking at the Chatham record on the UK site, it still contains the errors described by Steve in comment #61. The version on the GISS website contains the corrections / changes Steve noted.

Steve dryly responded:

So Hansen and his boys are manually editing data. My, my. This GISTEMP thing really is a pig.

We bumped into this by accident a full ten days after the changes were made, and it seems another 19 or so days were required to post the update notice on the GISS website. Right now, if one looks at the bottom of the GISS page, one will find:

GISS Website Curator: Robert B. Schmunk
Responsible NASA Official: James E. Hansen
Page updated: 2008-07-08

I’d love to look at earlier versions of Unfortunately, they are not archived by the wayback machine. I am surprised changes were made after 8/2007, because the file ends with 2006 and the actual Chatham Islands data ends with one entry in 1998. The next latest entry is 1992. Why would the British Antarctic survey change that one dataset during the summer of 2007?


  1. Posted Jul 20, 2008 at 8:05 PM | Permalink | Reply


    This is the third Gistemp sources drop I mentioned in another thread, FWIW. I guess we will have to check the ftp site from time to time ;).

  2. steven mosher
    Posted Jul 20, 2008 at 8:24 PM | Permalink | Reply

    John I have spare crazy pills.

  3. Steve McIntyre
    Posted Jul 20, 2008 at 8:31 PM | Permalink | Reply

    Re the GISS sentence:

    Finally, some errors were noticed on (set of stations not included in Met READER) that were not present before 8/2007. We replaced those outliers with the originally reported values

    I don’t recall that sentence being there before and it’s the sort of weird sentence that I’m inclined to notice :)

  4. Perry
    Posted Jul 21, 2008 at 1:37 AM | Permalink | Reply

    These must be desperate times for Hansen et al and where they seem to lose the plot is in not realising that changing data will not start a rush of sunspots, not can the revised data reverse the PDO. What are they hoping for? A magic spell? This year’s summer in the UK is not very satisfactory and summer next year will be even cooler. The BBC has made no reference to the effect on harvests, but British farmers will be aware of what their potential yields will be.

    You would expect a contractor to take best advice about weather when building a cafeteria at the top of a mountain, but it seems that the AGW scam deceived the management. Naturally, the BBC does not allude to global cooling in the report.

    “Britain’s highest building site on the summit of Snowdon

    The opening of the new £8.35m cafe on the summit of Snowdon has been further delayed because of bad weather.

    The building, to be called Hafod Eryri, was supposed to be completed this summer, but contractors now say they do not know when it will be finished.

    In April workers had to dig snow off the railway track to get to work at the highest spot in Wales or England.

    Snowdonia National Park Authority said since March 70 days’ work were lost to weather on the 3,560ft (1,085m) peak.

    However, the authority said progress on the scheme had been “remarkable” considering the conditions, including snow, heavy rain and winds regularly gusting over 80 mph.”

    See more.


  5. D. Patterson
    Posted Jul 21, 2008 at 2:20 AM | Permalink | Reply

    Perry says:

    July 21st, 2008 at 1:37 am
    These must be desperate times for Hansen et al and where they seem to lose the plot is in not realising that changing data will not start a rush of sunspots, not can the revised data reverse the PDO. What are they hoping for? A magic spell?

    NASA says “The reported temperature is truly meaningful only to a person who happens to visit the weather station at the precise moment when the reported temperature is measured, in other words, to nobody.”

    GISS Surface Temperature Analysis
    The Elusive Absolute Surface Air Temperature (SAT)
    Q. What exactly do we mean by SAT ?
    A. I doubt that there is a general agreement how to answer this question. Even at the same location, the temperature near the ground may be very different from the temperature 5 ft above the ground and different again from 10 ft or 50 ft above the ground. Particularly in the presence of vegetation (say in a rain forest), the temperature above the vegetation may be very different from the temperature below the top of the vegetation. A reasonable suggestion might be to use the average temperature of the first 50 ft of air either above ground or above the top of the vegetation. To measure SAT we have to agree on what it is and, as far as I know, no such standard has been suggested or generally adopted. Even if the 50 ft standard were adopted, I cannot imagine that a weather station would build a 50 ft stack of thermometers to be able to find the true SAT at its location.

    Q. What do we mean by daily mean SAT ?
    A. Again, there is no universally accepted correct answer. Should we note the temperature every 6 hours and report the mean, should we do it every 2 hours, hourly, have a machine record it every second, or simply take the average of the highest and lowest temperature of the day ? On some days the various methods may lead to drastically different results.

    Q. What SAT do the local media report ?
    A. The media report the reading of 1 particular thermometer of a nearby weather station. This temperature may be very different from the true SAT even at that location and has certainly nothing to do with the true regional SAT. To measure the true regional SAT, we would have to use many 50 ft stacks of thermometers distributed evenly over the whole region, an obvious practical impossibility.

    Q. If the reported SATs are not the true SATs, why are they still useful ?
    A. The reported temperature is truly meaningful only to a person who happens to visit the weather station at the precise moment when the reported temperature is measured, in other words, to nobody. However, in addition to the SAT the reports usually also mention whether the current temperature is unusually high or unusually low, how much it differs from the normal temperature, and that information (the anomaly) is meaningful for the whole region. Also, if we hear a temperature (say 70F), we instinctively translate it into hot or cold, but our translation key depends on the season and region, the same temperature may be ‘hot’ in winter and ‘cold’ in July, since by ‘hot’ we always mean ‘hotter than normal’, i.e. we all translate absolute temperatures automatically into anomalies whether we are aware of it or not.

    Q. If SATs cannot be measured, how are SAT maps created ?
    A. This can only be done with the help of computer models, the same models that are used to create the daily weather forecasts. We may start out the model with the few observed data that are available and fill in the rest with guesses (also called extrapolations) and then let the model run long enough so that the initial guesses no longer matter, but not too long in order to avoid that the inaccuracies of the model become relevant. This may be done starting from conditions from many years, so that the average (called a ‘climatology’) hopefully represents a typical map for the particular month or day of the year.

    Q. What do I do if I need absolute SATs, not anomalies ?
    A. In 99.9% of the cases you’ll find that anomalies are exactly what you need, not absolute temperatures. In the remaining cases, you have to pick one of the available climatologies and add the anomalies (with respect to the proper base period) to it. For the global mean, the most trusted models produce a value of roughly 14 Celsius, i.e. 57.2 F, but it may easily be anywhere between 56 and 58 F and regionally, let alone locally, the situation is even worse.

    Now you can see why NASA is untroubled by the use of computer models and constantly adjusted temperature datasets in place of the absolute temperatures reported by weather observations.

  6. cce
    Posted Jul 21, 2008 at 2:43 AM | Permalink | Reply

    It’s the first line on the main page. It’s also three quarters down the main page. It’s been there since early June, presumably June 7th.

  7. Scott-in-WA
    Posted Jul 21, 2008 at 4:07 AM | Permalink | Reply

    With each similar topic which appears on CA concerning the use of computer modeling for both climate data collection and long-term climate prediction, I continue to gain confidence in Scott’s Practical Alternative Model (SPAM): “Warming will continue at the long-term mean rate experienced since the end of the Little Ice Age until reaching the same peak as the Medievel Warm Period, at which point it will either continue or reverse.”

  8. Posted Jul 21, 2008 at 4:08 AM | Permalink | Reply

    Curiously, I searched through all of the “pdf” file links on the “Data Sets Images” link and right clicked them to look for their properties—-the ONLY date stamp for any “pdf” files is located on the mysterious June 9 update, but the time stamp on those pdf files is 10 June, 2008.(????)

  9. John Goetz
    Posted Jul 21, 2008 at 5:58 AM | Permalink | Reply

    #6 cce

    It is possible that the page went live on June 7th (remember, I am not 100% certain it was missing on July 5), but I think we won’t know for sure until the archives appear online. To add further doubt, the graph and maps page linked to by the update says June 10 at the bottom.

  10. Keith W.
    Posted Jul 21, 2008 at 10:29 AM | Permalink | Reply

    D. Patterson #5 -
    snip – politic

    Seriously, I haven’t read that much philosophical-based redefinition of reality since reading “1984″ back in high school. If you want to have a scientific basis for comparing two data sets, the sets have to based upon similar general physical criteria involved in the collection of those sets. So, set the criteria, and if they are not met, throw out the comparison.

  11. SteveSadlov
    Posted Jul 21, 2008 at 12:24 PM | Permalink | Reply

    Well, we’ve all heard plenty about options backdating. Why not backdate “corrections” to “the surface record?” Equally sleazy.

  12. dearieme
    Posted Jul 21, 2008 at 1:42 PM | Permalink | Reply

    “The reported temperature is truly meaningful only..”: ‘truly meaningful’ is presumably distinct from ‘true’. Crooks!

  13. bernie
    Posted Jul 21, 2008 at 2:13 PM | Permalink | Reply

    Pinpointing when, why and how these changes occurred makes good sense, but it is counterproductive for “auditors” to be perennially in “attack” or “gotcha” mode. Given that there is to date no evidence of the NASA/GISS people “cooking the books” as opposed to making mistakes, being very uncooperative or even using what some see as problematic methods and assumptions – the primary concern should be to encourage more transparency and accessibility. To use the financial audit metaphor, the more you beat up those who surface inconsistencies or errors in the records, the more reluctant they will be to continue doing so and the fewer chances you will be able to fix the things that produced the errors, etc. It is great that John Goetz noted the correction but how about toning down the rhetoric and simply expressing interest in what led to these changes rather than continuing to pound on these guys like they are part of some nefarious scheme – as opposed to say the natural inclination to minimize or avoid embarrassment when inconsistencies emerge or a natural disinclination to give credit to some potent critics. It is a plus that they appear to be more forthright in identifying errors and changes, perhaps it is even the forerunner of more openness about how adjustments are actually being made.

  14. chris
    Posted Jul 21, 2008 at 2:43 PM | Permalink | Reply

    As far as I can tell, the only Chatham Island is the one that is east of New Zealand. This has a full weather station maintained by NIWA. Why is the record only partial and then reported from a secondary source? I note the weather there is now 8.1°C and 96% humidity so the weather station is live and they do radiosondes and the like there. I am sure David Wratt, an occasional commenter to your blogs, could comment on the quality and location of the data as he is in charge of NIWA

    It also should be one of the stations used to “correct” the Wellington data, also the subject of previous blogs

  15. cce
    Posted Jul 21, 2008 at 4:32 PM | Permalink | Reply


    I remember reading the notice on the main page between the time it was first posted, and the time when the changes took effect. I don’t remember the exact date, but I remember noting that the change hadn’t taken effect yet. That is, I had to have read it on June 7, or 8th.

  16. Dave Clarke
    Posted Jul 21, 2008 at 6:49 PM | Permalink | Reply


    I’m having a hard time following the point. It seems pretty clear that you simply missed it the first time around. I follow the GISS pages closely as well, and I’ve never noticed any mysteriously appearing updates, unlike, say, the Fraser Institute.

    Original ISPM news release, dated February 5, 2007:

    Current ISPM news release (also dated February 5, although it was obviously changed long after that):

    The very first finding in the original read:
    Data collected by weather satellites since 1979 continue to exhibit little evidence of atmospheric warming, with estimated trends ranging from nearly zero to the low end of past IPCC forecasts.

    Somewhere along the way, that got changed to:
    Data collected by weather satellites since 1979 continue to exhibit some evidence of lower atmospheric warming, with estimated trends ranging near the low end of past IPCC forecasts.

    Now there’s a real scandal for CA readers to get their teeth into!

  17. kuhnkat
    Posted Jul 21, 2008 at 7:28 PM | Permalink | Reply

    #16, Dave Clarke,

    What DATA was changed in the release??

    rewording a clumsily phrased opinion just doesn’t reach my alarm meter.

  18. John Goetz
    Posted Jul 21, 2008 at 7:39 PM | Permalink | Reply

    #16 David Clarke, you are very well likely correct in that I missed it the first time around, as did most others on this blog. Certainly I was looking for a specific section of that page and could have easily skimmed past the update. A lesson learned on my part.

    I applaud GISS for recording the update in what appears to be a timely manner, and I kick myself for not noticing it before June 19. It would have been helpful if the process change was noted somewhere in the GISStemp source directories, which is where we were all looking. Unfortunately, I have yet to locate a change log, which may be filed in a directory in which the public does not have access.

    Nevertheless, the readers of CA eventually did discover the change on June 19 by scouring the data. In the end, I think CA did a much better job describing the change than what is noted on GISS.

    As for scandals at the Frasier Institute, alas, I have never heard of them.

  19. Posted Jul 21, 2008 at 8:28 PM | Permalink | Reply

    Re #17
    Undoubtedly this refers to the early UAH MSU data which showed approximately zero trend, however errors were uncovered and subsequent reprocessing led to a positive trend.

  20. Geoff Sherrington
    Posted Jul 21, 2008 at 9:05 PM | Permalink | Reply

    The matter of frequent alteration of the record leads to moderately difficult consequences.

    We have had a major Australian review of Global Warming by economist Ross Garnaut, nearly 600 pages of it. The main evidence of the part of man in adding to global warming is a comparison of surface temperature change trends in the last 3 decades compared to the last 10 decades.

    The mathematics of the trend, of course, is influenced by the set of numbers used. If at a future date one wishes to revisit the trend analysis, then there could be problems in getting the correct numbers.

    The model that was used for global temperatures was attributed to Brohan et al updated 2008. From what I can glean (and I could be wrong) the most recent data might be later than the report was published.

    A simple question or two for you specialists on CA, if I may. Are these the best global temperature data? Question 2: What is the possibility that global error bars (not just those calculated on the final graph, but incorporating errors of measurement from the beginning, like thermometer quality variation), likely to be greater or less than the sprad of the data over the last 100 years or so? That is, is the signal buried in the noise and adjustments, or have we come to live with envisaged and discussed imperfections?

  21. Geoff Sherrington
    Posted Jul 21, 2008 at 9:21 PM | Permalink | Reply

    Re # 20 self

    Forgot to add the reference that I think pertains:

    Brohan, P., J J Kennedy, I Harris, S F B Tett, and P D Jones. 2006, Uncertainty estimates in regional and global observed temperature changes: A new data set from 1850. Journal of Geophysical Research 111 D12106.doi:1020/2005JD006546

  22. Ade
    Posted Jul 22, 2008 at 6:33 AM | Permalink | Reply

    The “last updated date” now reads “2008-06-10″… I wonder, does someone at GISS have a clock that’s running backwards?

    More to the point, why would they fiddle the website date like this? It seems such a stupid thing to do when the weird date(s) have already been noticed. Of course, maybe I’m crediting them with not being stupid, and perhaps that’s my error…

  23. Dave Clarke
    Posted Jul 23, 2008 at 2:24 PM | Permalink | Reply

    Re: #17, 19

    This is not a mere “rephrasing”. The original ISPM cited the raw MSU T2 data channel as a measure of tropospheric temperature instead of the TLT data (adjusted for stratospheric cooling). This mistake occurred not only in the text body, but also in the summary of findings and the news release.

    The original ISPM noted a low-end estimate (from the University of Alabama team) of 0.4 deg C/decade (or “nearly zero”); the revised ISPM replaced this with the correct figure (0.12 deg. C/decade) and dropped the reference to “nearly zero.”

    See the original reference in #16 for all the details.

    The Fraser Institute and lead author have never admitted the error, apparently preferring to cover it up and hoping no one would notice.

    Of course, there remain numerous other (uncorrected) errors and discrepancies in the ISPM, but this was the most obvious.

  24. Dave Clarke
    Posted Jul 25, 2008 at 12:05 AM | Permalink | Reply

    Sorry that should have read:
    The original ISPM noted a low-end estimate (from the University of Alabama team) of *0.04* deg C/decade (or “nearly zero”); the revised ISPM replaced this with the correct figure (0.12 deg. C/decade) and dropped the reference to “nearly zero.”

    BTW, Some entertaining howlers in Gunter’s National Post piece of July 21; perhaps some eagle-eyed CA readers can find all of them. I found two without really trying:

    “Indeed, worldwide, there are nearly half as many glaciers advancing as retreating.”

    “Snow coverage in North America this winter was greater than at any time in recorded history.”

    No references, so we can’t check his supposed data sources, but the statemenrs are completely wrong of course. Now there’s a guy who needs to be audited – where on earth does he get this stuff?

  25. Sean
    Posted Jul 26, 2008 at 6:56 AM | Permalink | Reply

    Dave Clark
    Funny you should complain about Lorne Gunter not providing a source and then not provide a link to the article in question. Here it is:
    I agree with you however in that his statement “Snow coverage in North America this winter was greater than at any time in recorded history.” appears to be incorrect. According to the Rutgers University Global Snow Lab;
    The first three months of 2008 was the 10th highest out of 42 years

  26. RomanM
    Posted Jul 26, 2008 at 11:48 AM | Permalink | Reply

    Mr. Gunter may have gotten his place names mixed up a bit. In fact, the following statement does appear to be true:

    “Snow coverage in the Northern Hemisphere this January was greater than at any other January in the Rutger’s data set (and second only to February, 1978 for the greatest overall amount).”

    Of course, not being a climate scientist, he can’t go back and “adjust” past history. :)

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